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1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of version 2 of the GNU General Public
6  * License as published by the Free Software Foundation.
7  */
8 #ifndef _UAPI__LINUX_BPF_H__
9 #define _UAPI__LINUX_BPF_H__
10 
11 #include <linux/types.h>
12 #include <linux/bpf_common.h>
13 
14 /* Extended instruction set based on top of classic BPF */
15 
16 /* instruction classes */
17 #define BPF_JMP32	0x06	/* jmp mode in word width */
18 #define BPF_ALU64	0x07	/* alu mode in double word width */
19 
20 /* ld/ldx fields */
21 #define BPF_DW		0x18	/* double word (64-bit) */
22 #define BPF_ATOMIC	0xc0	/* atomic memory ops - op type in immediate */
23 #define BPF_XADD	0xc0	/* exclusive add - legacy name */
24 
25 /* alu/jmp fields */
26 #define BPF_MOV		0xb0	/* mov reg to reg */
27 #define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
28 
29 /* change endianness of a register */
30 #define BPF_END		0xd0	/* flags for endianness conversion: */
31 #define BPF_TO_LE	0x00	/* convert to little-endian */
32 #define BPF_TO_BE	0x08	/* convert to big-endian */
33 #define BPF_FROM_LE	BPF_TO_LE
34 #define BPF_FROM_BE	BPF_TO_BE
35 
36 /* jmp encodings */
37 #define BPF_JNE		0x50	/* jump != */
38 #define BPF_JLT		0xa0	/* LT is unsigned, '<' */
39 #define BPF_JLE		0xb0	/* LE is unsigned, '<=' */
40 #define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
41 #define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
42 #define BPF_JSLT	0xc0	/* SLT is signed, '<' */
43 #define BPF_JSLE	0xd0	/* SLE is signed, '<=' */
44 #define BPF_CALL	0x80	/* function call */
45 #define BPF_EXIT	0x90	/* function return */
46 
47 /* atomic op type fields (stored in immediate) */
48 #define BPF_FETCH	0x01	/* not an opcode on its own, used to build others */
49 #define BPF_XCHG	(0xe0 | BPF_FETCH)	/* atomic exchange */
50 #define BPF_CMPXCHG	(0xf0 | BPF_FETCH)	/* atomic compare-and-write */
51 
52 /* Register numbers */
53 enum {
54 	BPF_REG_0 = 0,
55 	BPF_REG_1,
56 	BPF_REG_2,
57 	BPF_REG_3,
58 	BPF_REG_4,
59 	BPF_REG_5,
60 	BPF_REG_6,
61 	BPF_REG_7,
62 	BPF_REG_8,
63 	BPF_REG_9,
64 	BPF_REG_10,
65 	__MAX_BPF_REG,
66 };
67 
68 /* BPF has 10 general purpose 64-bit registers and stack frame. */
69 #define MAX_BPF_REG	__MAX_BPF_REG
70 
71 struct bpf_insn {
72 	__u8	code;		/* opcode */
73 	__u8	dst_reg:4;	/* dest register */
74 	__u8	src_reg:4;	/* source register */
75 	__s16	off;		/* signed offset */
76 	__s32	imm;		/* signed immediate constant */
77 };
78 
79 /* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
80 struct bpf_lpm_trie_key {
81 	__u32	prefixlen;	/* up to 32 for AF_INET, 128 for AF_INET6 */
82 	__u8	data[0];	/* Arbitrary size */
83 };
84 
85 struct bpf_cgroup_storage_key {
86 	__u64	cgroup_inode_id;	/* cgroup inode id */
87 	__u32	attach_type;		/* program attach type (enum bpf_attach_type) */
88 };
89 
90 union bpf_iter_link_info {
91 	struct {
92 		__u32	map_fd;
93 	} map;
94 };
95 
96 /* BPF syscall commands, see bpf(2) man-page for more details. */
97 /**
98  * DOC: eBPF Syscall Preamble
99  *
100  * The operation to be performed by the **bpf**\ () system call is determined
101  * by the *cmd* argument. Each operation takes an accompanying argument,
102  * provided via *attr*, which is a pointer to a union of type *bpf_attr* (see
103  * below). The size argument is the size of the union pointed to by *attr*.
104  */
105 /**
106  * DOC: eBPF Syscall Commands
107  *
108  * BPF_MAP_CREATE
109  *	Description
110  *		Create a map and return a file descriptor that refers to the
111  *		map. The close-on-exec file descriptor flag (see **fcntl**\ (2))
112  *		is automatically enabled for the new file descriptor.
113  *
114  *		Applying **close**\ (2) to the file descriptor returned by
115  *		**BPF_MAP_CREATE** will delete the map (but see NOTES).
116  *
117  *	Return
118  *		A new file descriptor (a nonnegative integer), or -1 if an
119  *		error occurred (in which case, *errno* is set appropriately).
120  *
121  * BPF_MAP_LOOKUP_ELEM
122  *	Description
123  *		Look up an element with a given *key* in the map referred to
124  *		by the file descriptor *map_fd*.
125  *
126  *		The *flags* argument may be specified as one of the
127  *		following:
128  *
129  *		**BPF_F_LOCK**
130  *			Look up the value of a spin-locked map without
131  *			returning the lock. This must be specified if the
132  *			elements contain a spinlock.
133  *
134  *	Return
135  *		Returns zero on success. On error, -1 is returned and *errno*
136  *		is set appropriately.
137  *
138  * BPF_MAP_UPDATE_ELEM
139  *	Description
140  *		Create or update an element (key/value pair) in a specified map.
141  *
142  *		The *flags* argument should be specified as one of the
143  *		following:
144  *
145  *		**BPF_ANY**
146  *			Create a new element or update an existing element.
147  *		**BPF_NOEXIST**
148  *			Create a new element only if it did not exist.
149  *		**BPF_EXIST**
150  *			Update an existing element.
151  *		**BPF_F_LOCK**
152  *			Update a spin_lock-ed map element.
153  *
154  *	Return
155  *		Returns zero on success. On error, -1 is returned and *errno*
156  *		is set appropriately.
157  *
158  *		May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**,
159  *		**E2BIG**, **EEXIST**, or **ENOENT**.
160  *
161  *		**E2BIG**
162  *			The number of elements in the map reached the
163  *			*max_entries* limit specified at map creation time.
164  *		**EEXIST**
165  *			If *flags* specifies **BPF_NOEXIST** and the element
166  *			with *key* already exists in the map.
167  *		**ENOENT**
168  *			If *flags* specifies **BPF_EXIST** and the element with
169  *			*key* does not exist in the map.
170  *
171  * BPF_MAP_DELETE_ELEM
172  *	Description
173  *		Look up and delete an element by key in a specified map.
174  *
175  *	Return
176  *		Returns zero on success. On error, -1 is returned and *errno*
177  *		is set appropriately.
178  *
179  * BPF_MAP_GET_NEXT_KEY
180  *	Description
181  *		Look up an element by key in a specified map and return the key
182  *		of the next element. Can be used to iterate over all elements
183  *		in the map.
184  *
185  *	Return
186  *		Returns zero on success. On error, -1 is returned and *errno*
187  *		is set appropriately.
188  *
189  *		The following cases can be used to iterate over all elements of
190  *		the map:
191  *
192  *		* If *key* is not found, the operation returns zero and sets
193  *		  the *next_key* pointer to the key of the first element.
194  *		* If *key* is found, the operation returns zero and sets the
195  *		  *next_key* pointer to the key of the next element.
196  *		* If *key* is the last element, returns -1 and *errno* is set
197  *		  to **ENOENT**.
198  *
199  *		May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or
200  *		**EINVAL** on error.
201  *
202  * BPF_PROG_LOAD
203  *	Description
204  *		Verify and load an eBPF program, returning a new file
205  *		descriptor associated with the program.
206  *
207  *		Applying **close**\ (2) to the file descriptor returned by
208  *		**BPF_PROG_LOAD** will unload the eBPF program (but see NOTES).
209  *
210  *		The close-on-exec file descriptor flag (see **fcntl**\ (2)) is
211  *		automatically enabled for the new file descriptor.
212  *
213  *	Return
214  *		A new file descriptor (a nonnegative integer), or -1 if an
215  *		error occurred (in which case, *errno* is set appropriately).
216  *
217  * BPF_OBJ_PIN
218  *	Description
219  *		Pin an eBPF program or map referred by the specified *bpf_fd*
220  *		to the provided *pathname* on the filesystem.
221  *
222  *		The *pathname* argument must not contain a dot (".").
223  *
224  *		On success, *pathname* retains a reference to the eBPF object,
225  *		preventing deallocation of the object when the original
226  *		*bpf_fd* is closed. This allow the eBPF object to live beyond
227  *		**close**\ (\ *bpf_fd*\ ), and hence the lifetime of the parent
228  *		process.
229  *
230  *		Applying **unlink**\ (2) or similar calls to the *pathname*
231  *		unpins the object from the filesystem, removing the reference.
232  *		If no other file descriptors or filesystem nodes refer to the
233  *		same object, it will be deallocated (see NOTES).
234  *
235  *		The filesystem type for the parent directory of *pathname* must
236  *		be **BPF_FS_MAGIC**.
237  *
238  *	Return
239  *		Returns zero on success. On error, -1 is returned and *errno*
240  *		is set appropriately.
241  *
242  * BPF_OBJ_GET
243  *	Description
244  *		Open a file descriptor for the eBPF object pinned to the
245  *		specified *pathname*.
246  *
247  *	Return
248  *		A new file descriptor (a nonnegative integer), or -1 if an
249  *		error occurred (in which case, *errno* is set appropriately).
250  *
251  * BPF_PROG_ATTACH
252  *	Description
253  *		Attach an eBPF program to a *target_fd* at the specified
254  *		*attach_type* hook.
255  *
256  *		The *attach_type* specifies the eBPF attachment point to
257  *		attach the program to, and must be one of *bpf_attach_type*
258  *		(see below).
259  *
260  *		The *attach_bpf_fd* must be a valid file descriptor for a
261  *		loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
262  *		or sock_ops type corresponding to the specified *attach_type*.
263  *
264  *		The *target_fd* must be a valid file descriptor for a kernel
265  *		object which depends on the attach type of *attach_bpf_fd*:
266  *
267  *		**BPF_PROG_TYPE_CGROUP_DEVICE**,
268  *		**BPF_PROG_TYPE_CGROUP_SKB**,
269  *		**BPF_PROG_TYPE_CGROUP_SOCK**,
270  *		**BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
271  *		**BPF_PROG_TYPE_CGROUP_SOCKOPT**,
272  *		**BPF_PROG_TYPE_CGROUP_SYSCTL**,
273  *		**BPF_PROG_TYPE_SOCK_OPS**
274  *
275  *			Control Group v2 hierarchy with the eBPF controller
276  *			enabled. Requires the kernel to be compiled with
277  *			**CONFIG_CGROUP_BPF**.
278  *
279  *		**BPF_PROG_TYPE_FLOW_DISSECTOR**
280  *
281  *			Network namespace (eg /proc/self/ns/net).
282  *
283  *		**BPF_PROG_TYPE_LIRC_MODE2**
284  *
285  *			LIRC device path (eg /dev/lircN). Requires the kernel
286  *			to be compiled with **CONFIG_BPF_LIRC_MODE2**.
287  *
288  *		**BPF_PROG_TYPE_SK_SKB**,
289  *		**BPF_PROG_TYPE_SK_MSG**
290  *
291  *			eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
292  *
293  *	Return
294  *		Returns zero on success. On error, -1 is returned and *errno*
295  *		is set appropriately.
296  *
297  * BPF_PROG_DETACH
298  *	Description
299  *		Detach the eBPF program associated with the *target_fd* at the
300  *		hook specified by *attach_type*. The program must have been
301  *		previously attached using **BPF_PROG_ATTACH**.
302  *
303  *	Return
304  *		Returns zero on success. On error, -1 is returned and *errno*
305  *		is set appropriately.
306  *
307  * BPF_PROG_TEST_RUN
308  *	Description
309  *		Run the eBPF program associated with the *prog_fd* a *repeat*
310  *		number of times against a provided program context *ctx_in* and
311  *		data *data_in*, and return the modified program context
312  *		*ctx_out*, *data_out* (for example, packet data), result of the
313  *		execution *retval*, and *duration* of the test run.
314  *
315  *		The sizes of the buffers provided as input and output
316  *		parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must
317  *		be provided in the corresponding variables *ctx_size_in*,
318  *		*ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any
319  *		of these parameters are not provided (ie set to NULL), the
320  *		corresponding size field must be zero.
321  *
322  *		Some program types have particular requirements:
323  *
324  *		**BPF_PROG_TYPE_SK_LOOKUP**
325  *			*data_in* and *data_out* must be NULL.
326  *
327  *		**BPF_PROG_TYPE_RAW_TRACEPOINT**,
328  *		**BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**
329  *
330  *			*ctx_out*, *data_in* and *data_out* must be NULL.
331  *			*repeat* must be zero.
332  *
333  *	Return
334  *		Returns zero on success. On error, -1 is returned and *errno*
335  *		is set appropriately.
336  *
337  *		**ENOSPC**
338  *			Either *data_size_out* or *ctx_size_out* is too small.
339  *		**ENOTSUPP**
340  *			This command is not supported by the program type of
341  *			the program referred to by *prog_fd*.
342  *
343  * BPF_PROG_GET_NEXT_ID
344  *	Description
345  *		Fetch the next eBPF program currently loaded into the kernel.
346  *
347  *		Looks for the eBPF program with an id greater than *start_id*
348  *		and updates *next_id* on success. If no other eBPF programs
349  *		remain with ids higher than *start_id*, returns -1 and sets
350  *		*errno* to **ENOENT**.
351  *
352  *	Return
353  *		Returns zero on success. On error, or when no id remains, -1
354  *		is returned and *errno* is set appropriately.
355  *
356  * BPF_MAP_GET_NEXT_ID
357  *	Description
358  *		Fetch the next eBPF map currently loaded into the kernel.
359  *
360  *		Looks for the eBPF map with an id greater than *start_id*
361  *		and updates *next_id* on success. If no other eBPF maps
362  *		remain with ids higher than *start_id*, returns -1 and sets
363  *		*errno* to **ENOENT**.
364  *
365  *	Return
366  *		Returns zero on success. On error, or when no id remains, -1
367  *		is returned and *errno* is set appropriately.
368  *
369  * BPF_PROG_GET_FD_BY_ID
370  *	Description
371  *		Open a file descriptor for the eBPF program corresponding to
372  *		*prog_id*.
373  *
374  *	Return
375  *		A new file descriptor (a nonnegative integer), or -1 if an
376  *		error occurred (in which case, *errno* is set appropriately).
377  *
378  * BPF_MAP_GET_FD_BY_ID
379  *	Description
380  *		Open a file descriptor for the eBPF map corresponding to
381  *		*map_id*.
382  *
383  *	Return
384  *		A new file descriptor (a nonnegative integer), or -1 if an
385  *		error occurred (in which case, *errno* is set appropriately).
386  *
387  * BPF_OBJ_GET_INFO_BY_FD
388  *	Description
389  *		Obtain information about the eBPF object corresponding to
390  *		*bpf_fd*.
391  *
392  *		Populates up to *info_len* bytes of *info*, which will be in
393  *		one of the following formats depending on the eBPF object type
394  *		of *bpf_fd*:
395  *
396  *		* **struct bpf_prog_info**
397  *		* **struct bpf_map_info**
398  *		* **struct bpf_btf_info**
399  *		* **struct bpf_link_info**
400  *
401  *	Return
402  *		Returns zero on success. On error, -1 is returned and *errno*
403  *		is set appropriately.
404  *
405  * BPF_PROG_QUERY
406  *	Description
407  *		Obtain information about eBPF programs associated with the
408  *		specified *attach_type* hook.
409  *
410  *		The *target_fd* must be a valid file descriptor for a kernel
411  *		object which depends on the attach type of *attach_bpf_fd*:
412  *
413  *		**BPF_PROG_TYPE_CGROUP_DEVICE**,
414  *		**BPF_PROG_TYPE_CGROUP_SKB**,
415  *		**BPF_PROG_TYPE_CGROUP_SOCK**,
416  *		**BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
417  *		**BPF_PROG_TYPE_CGROUP_SOCKOPT**,
418  *		**BPF_PROG_TYPE_CGROUP_SYSCTL**,
419  *		**BPF_PROG_TYPE_SOCK_OPS**
420  *
421  *			Control Group v2 hierarchy with the eBPF controller
422  *			enabled. Requires the kernel to be compiled with
423  *			**CONFIG_CGROUP_BPF**.
424  *
425  *		**BPF_PROG_TYPE_FLOW_DISSECTOR**
426  *
427  *			Network namespace (eg /proc/self/ns/net).
428  *
429  *		**BPF_PROG_TYPE_LIRC_MODE2**
430  *
431  *			LIRC device path (eg /dev/lircN). Requires the kernel
432  *			to be compiled with **CONFIG_BPF_LIRC_MODE2**.
433  *
434  *		**BPF_PROG_QUERY** always fetches the number of programs
435  *		attached and the *attach_flags* which were used to attach those
436  *		programs. Additionally, if *prog_ids* is nonzero and the number
437  *		of attached programs is less than *prog_cnt*, populates
438  *		*prog_ids* with the eBPF program ids of the programs attached
439  *		at *target_fd*.
440  *
441  *		The following flags may alter the result:
442  *
443  *		**BPF_F_QUERY_EFFECTIVE**
444  *			Only return information regarding programs which are
445  *			currently effective at the specified *target_fd*.
446  *
447  *	Return
448  *		Returns zero on success. On error, -1 is returned and *errno*
449  *		is set appropriately.
450  *
451  * BPF_RAW_TRACEPOINT_OPEN
452  *	Description
453  *		Attach an eBPF program to a tracepoint *name* to access kernel
454  *		internal arguments of the tracepoint in their raw form.
455  *
456  *		The *prog_fd* must be a valid file descriptor associated with
457  *		a loaded eBPF program of type **BPF_PROG_TYPE_RAW_TRACEPOINT**.
458  *
459  *		No ABI guarantees are made about the content of tracepoint
460  *		arguments exposed to the corresponding eBPF program.
461  *
462  *		Applying **close**\ (2) to the file descriptor returned by
463  *		**BPF_RAW_TRACEPOINT_OPEN** will delete the map (but see NOTES).
464  *
465  *	Return
466  *		A new file descriptor (a nonnegative integer), or -1 if an
467  *		error occurred (in which case, *errno* is set appropriately).
468  *
469  * BPF_BTF_LOAD
470  *	Description
471  *		Verify and load BPF Type Format (BTF) metadata into the kernel,
472  *		returning a new file descriptor associated with the metadata.
473  *		BTF is described in more detail at
474  *		https://www.kernel.org/doc/html/latest/bpf/btf.html.
475  *
476  *		The *btf* parameter must point to valid memory providing
477  *		*btf_size* bytes of BTF binary metadata.
478  *
479  *		The returned file descriptor can be passed to other **bpf**\ ()
480  *		subcommands such as **BPF_PROG_LOAD** or **BPF_MAP_CREATE** to
481  *		associate the BTF with those objects.
482  *
483  *		Similar to **BPF_PROG_LOAD**, **BPF_BTF_LOAD** has optional
484  *		parameters to specify a *btf_log_buf*, *btf_log_size* and
485  *		*btf_log_level* which allow the kernel to return freeform log
486  *		output regarding the BTF verification process.
487  *
488  *	Return
489  *		A new file descriptor (a nonnegative integer), or -1 if an
490  *		error occurred (in which case, *errno* is set appropriately).
491  *
492  * BPF_BTF_GET_FD_BY_ID
493  *	Description
494  *		Open a file descriptor for the BPF Type Format (BTF)
495  *		corresponding to *btf_id*.
496  *
497  *	Return
498  *		A new file descriptor (a nonnegative integer), or -1 if an
499  *		error occurred (in which case, *errno* is set appropriately).
500  *
501  * BPF_TASK_FD_QUERY
502  *	Description
503  *		Obtain information about eBPF programs associated with the
504  *		target process identified by *pid* and *fd*.
505  *
506  *		If the *pid* and *fd* are associated with a tracepoint, kprobe
507  *		or uprobe perf event, then the *prog_id* and *fd_type* will
508  *		be populated with the eBPF program id and file descriptor type
509  *		of type **bpf_task_fd_type**. If associated with a kprobe or
510  *		uprobe, the  *probe_offset* and *probe_addr* will also be
511  *		populated. Optionally, if *buf* is provided, then up to
512  *		*buf_len* bytes of *buf* will be populated with the name of
513  *		the tracepoint, kprobe or uprobe.
514  *
515  *		The resulting *prog_id* may be introspected in deeper detail
516  *		using **BPF_PROG_GET_FD_BY_ID** and **BPF_OBJ_GET_INFO_BY_FD**.
517  *
518  *	Return
519  *		Returns zero on success. On error, -1 is returned and *errno*
520  *		is set appropriately.
521  *
522  * BPF_MAP_LOOKUP_AND_DELETE_ELEM
523  *	Description
524  *		Look up an element with the given *key* in the map referred to
525  *		by the file descriptor *fd*, and if found, delete the element.
526  *
527  *		For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map
528  *		types, the *flags* argument needs to be set to 0, but for other
529  *		map types, it may be specified as:
530  *
531  *		**BPF_F_LOCK**
532  *			Look up and delete the value of a spin-locked map
533  *			without returning the lock. This must be specified if
534  *			the elements contain a spinlock.
535  *
536  *		The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types
537  *		implement this command as a "pop" operation, deleting the top
538  *		element rather than one corresponding to *key*.
539  *		The *key* and *key_len* parameters should be zeroed when
540  *		issuing this operation for these map types.
541  *
542  *		This command is only valid for the following map types:
543  *		* **BPF_MAP_TYPE_QUEUE**
544  *		* **BPF_MAP_TYPE_STACK**
545  *		* **BPF_MAP_TYPE_HASH**
546  *		* **BPF_MAP_TYPE_PERCPU_HASH**
547  *		* **BPF_MAP_TYPE_LRU_HASH**
548  *		* **BPF_MAP_TYPE_LRU_PERCPU_HASH**
549  *
550  *	Return
551  *		Returns zero on success. On error, -1 is returned and *errno*
552  *		is set appropriately.
553  *
554  * BPF_MAP_FREEZE
555  *	Description
556  *		Freeze the permissions of the specified map.
557  *
558  *		Write permissions may be frozen by passing zero *flags*.
559  *		Upon success, no future syscall invocations may alter the
560  *		map state of *map_fd*. Write operations from eBPF programs
561  *		are still possible for a frozen map.
562  *
563  *		Not supported for maps of type **BPF_MAP_TYPE_STRUCT_OPS**.
564  *
565  *	Return
566  *		Returns zero on success. On error, -1 is returned and *errno*
567  *		is set appropriately.
568  *
569  * BPF_BTF_GET_NEXT_ID
570  *	Description
571  *		Fetch the next BPF Type Format (BTF) object currently loaded
572  *		into the kernel.
573  *
574  *		Looks for the BTF object with an id greater than *start_id*
575  *		and updates *next_id* on success. If no other BTF objects
576  *		remain with ids higher than *start_id*, returns -1 and sets
577  *		*errno* to **ENOENT**.
578  *
579  *	Return
580  *		Returns zero on success. On error, or when no id remains, -1
581  *		is returned and *errno* is set appropriately.
582  *
583  * BPF_MAP_LOOKUP_BATCH
584  *	Description
585  *		Iterate and fetch multiple elements in a map.
586  *
587  *		Two opaque values are used to manage batch operations,
588  *		*in_batch* and *out_batch*. Initially, *in_batch* must be set
589  *		to NULL to begin the batched operation. After each subsequent
590  *		**BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant
591  *		*out_batch* as the *in_batch* for the next operation to
592  *		continue iteration from the current point.
593  *
594  *		The *keys* and *values* are output parameters which must point
595  *		to memory large enough to hold *count* items based on the key
596  *		and value size of the map *map_fd*. The *keys* buffer must be
597  *		of *key_size* * *count*. The *values* buffer must be of
598  *		*value_size* * *count*.
599  *
600  *		The *elem_flags* argument may be specified as one of the
601  *		following:
602  *
603  *		**BPF_F_LOCK**
604  *			Look up the value of a spin-locked map without
605  *			returning the lock. This must be specified if the
606  *			elements contain a spinlock.
607  *
608  *		On success, *count* elements from the map are copied into the
609  *		user buffer, with the keys copied into *keys* and the values
610  *		copied into the corresponding indices in *values*.
611  *
612  *		If an error is returned and *errno* is not **EFAULT**, *count*
613  *		is set to the number of successfully processed elements.
614  *
615  *	Return
616  *		Returns zero on success. On error, -1 is returned and *errno*
617  *		is set appropriately.
618  *
619  *		May set *errno* to **ENOSPC** to indicate that *keys* or
620  *		*values* is too small to dump an entire bucket during
621  *		iteration of a hash-based map type.
622  *
623  * BPF_MAP_LOOKUP_AND_DELETE_BATCH
624  *	Description
625  *		Iterate and delete all elements in a map.
626  *
627  *		This operation has the same behavior as
628  *		**BPF_MAP_LOOKUP_BATCH** with two exceptions:
629  *
630  *		* Every element that is successfully returned is also deleted
631  *		  from the map. This is at least *count* elements. Note that
632  *		  *count* is both an input and an output parameter.
633  *		* Upon returning with *errno* set to **EFAULT**, up to
634  *		  *count* elements may be deleted without returning the keys
635  *		  and values of the deleted elements.
636  *
637  *	Return
638  *		Returns zero on success. On error, -1 is returned and *errno*
639  *		is set appropriately.
640  *
641  * BPF_MAP_UPDATE_BATCH
642  *	Description
643  *		Update multiple elements in a map by *key*.
644  *
645  *		The *keys* and *values* are input parameters which must point
646  *		to memory large enough to hold *count* items based on the key
647  *		and value size of the map *map_fd*. The *keys* buffer must be
648  *		of *key_size* * *count*. The *values* buffer must be of
649  *		*value_size* * *count*.
650  *
651  *		Each element specified in *keys* is sequentially updated to the
652  *		value in the corresponding index in *values*. The *in_batch*
653  *		and *out_batch* parameters are ignored and should be zeroed.
654  *
655  *		The *elem_flags* argument should be specified as one of the
656  *		following:
657  *
658  *		**BPF_ANY**
659  *			Create new elements or update a existing elements.
660  *		**BPF_NOEXIST**
661  *			Create new elements only if they do not exist.
662  *		**BPF_EXIST**
663  *			Update existing elements.
664  *		**BPF_F_LOCK**
665  *			Update spin_lock-ed map elements. This must be
666  *			specified if the map value contains a spinlock.
667  *
668  *		On success, *count* elements from the map are updated.
669  *
670  *		If an error is returned and *errno* is not **EFAULT**, *count*
671  *		is set to the number of successfully processed elements.
672  *
673  *	Return
674  *		Returns zero on success. On error, -1 is returned and *errno*
675  *		is set appropriately.
676  *
677  *		May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or
678  *		**E2BIG**. **E2BIG** indicates that the number of elements in
679  *		the map reached the *max_entries* limit specified at map
680  *		creation time.
681  *
682  *		May set *errno* to one of the following error codes under
683  *		specific circumstances:
684  *
685  *		**EEXIST**
686  *			If *flags* specifies **BPF_NOEXIST** and the element
687  *			with *key* already exists in the map.
688  *		**ENOENT**
689  *			If *flags* specifies **BPF_EXIST** and the element with
690  *			*key* does not exist in the map.
691  *
692  * BPF_MAP_DELETE_BATCH
693  *	Description
694  *		Delete multiple elements in a map by *key*.
695  *
696  *		The *keys* parameter is an input parameter which must point
697  *		to memory large enough to hold *count* items based on the key
698  *		size of the map *map_fd*, that is, *key_size* * *count*.
699  *
700  *		Each element specified in *keys* is sequentially deleted. The
701  *		*in_batch*, *out_batch*, and *values* parameters are ignored
702  *		and should be zeroed.
703  *
704  *		The *elem_flags* argument may be specified as one of the
705  *		following:
706  *
707  *		**BPF_F_LOCK**
708  *			Look up the value of a spin-locked map without
709  *			returning the lock. This must be specified if the
710  *			elements contain a spinlock.
711  *
712  *		On success, *count* elements from the map are updated.
713  *
714  *		If an error is returned and *errno* is not **EFAULT**, *count*
715  *		is set to the number of successfully processed elements. If
716  *		*errno* is **EFAULT**, up to *count* elements may be been
717  *		deleted.
718  *
719  *	Return
720  *		Returns zero on success. On error, -1 is returned and *errno*
721  *		is set appropriately.
722  *
723  * BPF_LINK_CREATE
724  *	Description
725  *		Attach an eBPF program to a *target_fd* at the specified
726  *		*attach_type* hook and return a file descriptor handle for
727  *		managing the link.
728  *
729  *	Return
730  *		A new file descriptor (a nonnegative integer), or -1 if an
731  *		error occurred (in which case, *errno* is set appropriately).
732  *
733  * BPF_LINK_UPDATE
734  *	Description
735  *		Update the eBPF program in the specified *link_fd* to
736  *		*new_prog_fd*.
737  *
738  *	Return
739  *		Returns zero on success. On error, -1 is returned and *errno*
740  *		is set appropriately.
741  *
742  * BPF_LINK_GET_FD_BY_ID
743  *	Description
744  *		Open a file descriptor for the eBPF Link corresponding to
745  *		*link_id*.
746  *
747  *	Return
748  *		A new file descriptor (a nonnegative integer), or -1 if an
749  *		error occurred (in which case, *errno* is set appropriately).
750  *
751  * BPF_LINK_GET_NEXT_ID
752  *	Description
753  *		Fetch the next eBPF link currently loaded into the kernel.
754  *
755  *		Looks for the eBPF link with an id greater than *start_id*
756  *		and updates *next_id* on success. If no other eBPF links
757  *		remain with ids higher than *start_id*, returns -1 and sets
758  *		*errno* to **ENOENT**.
759  *
760  *	Return
761  *		Returns zero on success. On error, or when no id remains, -1
762  *		is returned and *errno* is set appropriately.
763  *
764  * BPF_ENABLE_STATS
765  *	Description
766  *		Enable eBPF runtime statistics gathering.
767  *
768  *		Runtime statistics gathering for the eBPF runtime is disabled
769  *		by default to minimize the corresponding performance overhead.
770  *		This command enables statistics globally.
771  *
772  *		Multiple programs may independently enable statistics.
773  *		After gathering the desired statistics, eBPF runtime statistics
774  *		may be disabled again by calling **close**\ (2) for the file
775  *		descriptor returned by this function. Statistics will only be
776  *		disabled system-wide when all outstanding file descriptors
777  *		returned by prior calls for this subcommand are closed.
778  *
779  *	Return
780  *		A new file descriptor (a nonnegative integer), or -1 if an
781  *		error occurred (in which case, *errno* is set appropriately).
782  *
783  * BPF_ITER_CREATE
784  *	Description
785  *		Create an iterator on top of the specified *link_fd* (as
786  *		previously created using **BPF_LINK_CREATE**) and return a
787  *		file descriptor that can be used to trigger the iteration.
788  *
789  *		If the resulting file descriptor is pinned to the filesystem
790  *		using  **BPF_OBJ_PIN**, then subsequent **read**\ (2) syscalls
791  *		for that path will trigger the iterator to read kernel state
792  *		using the eBPF program attached to *link_fd*.
793  *
794  *	Return
795  *		A new file descriptor (a nonnegative integer), or -1 if an
796  *		error occurred (in which case, *errno* is set appropriately).
797  *
798  * BPF_LINK_DETACH
799  *	Description
800  *		Forcefully detach the specified *link_fd* from its
801  *		corresponding attachment point.
802  *
803  *	Return
804  *		Returns zero on success. On error, -1 is returned and *errno*
805  *		is set appropriately.
806  *
807  * BPF_PROG_BIND_MAP
808  *	Description
809  *		Bind a map to the lifetime of an eBPF program.
810  *
811  *		The map identified by *map_fd* is bound to the program
812  *		identified by *prog_fd* and only released when *prog_fd* is
813  *		released. This may be used in cases where metadata should be
814  *		associated with a program which otherwise does not contain any
815  *		references to the map (for example, embedded in the eBPF
816  *		program instructions).
817  *
818  *	Return
819  *		Returns zero on success. On error, -1 is returned and *errno*
820  *		is set appropriately.
821  *
822  * NOTES
823  *	eBPF objects (maps and programs) can be shared between processes.
824  *
825  *	* After **fork**\ (2), the child inherits file descriptors
826  *	  referring to the same eBPF objects.
827  *	* File descriptors referring to eBPF objects can be transferred over
828  *	  **unix**\ (7) domain sockets.
829  *	* File descriptors referring to eBPF objects can be duplicated in the
830  *	  usual way, using **dup**\ (2) and similar calls.
831  *	* File descriptors referring to eBPF objects can be pinned to the
832  *	  filesystem using the **BPF_OBJ_PIN** command of **bpf**\ (2).
833  *
834  *	An eBPF object is deallocated only after all file descriptors referring
835  *	to the object have been closed and no references remain pinned to the
836  *	filesystem or attached (for example, bound to a program or device).
837  */
838 enum bpf_cmd {
839 	BPF_MAP_CREATE,
840 	BPF_MAP_LOOKUP_ELEM,
841 	BPF_MAP_UPDATE_ELEM,
842 	BPF_MAP_DELETE_ELEM,
843 	BPF_MAP_GET_NEXT_KEY,
844 	BPF_PROG_LOAD,
845 	BPF_OBJ_PIN,
846 	BPF_OBJ_GET,
847 	BPF_PROG_ATTACH,
848 	BPF_PROG_DETACH,
849 	BPF_PROG_TEST_RUN,
850 	BPF_PROG_RUN = BPF_PROG_TEST_RUN,
851 	BPF_PROG_GET_NEXT_ID,
852 	BPF_MAP_GET_NEXT_ID,
853 	BPF_PROG_GET_FD_BY_ID,
854 	BPF_MAP_GET_FD_BY_ID,
855 	BPF_OBJ_GET_INFO_BY_FD,
856 	BPF_PROG_QUERY,
857 	BPF_RAW_TRACEPOINT_OPEN,
858 	BPF_BTF_LOAD,
859 	BPF_BTF_GET_FD_BY_ID,
860 	BPF_TASK_FD_QUERY,
861 	BPF_MAP_LOOKUP_AND_DELETE_ELEM,
862 	BPF_MAP_FREEZE,
863 	BPF_BTF_GET_NEXT_ID,
864 	BPF_MAP_LOOKUP_BATCH,
865 	BPF_MAP_LOOKUP_AND_DELETE_BATCH,
866 	BPF_MAP_UPDATE_BATCH,
867 	BPF_MAP_DELETE_BATCH,
868 	BPF_LINK_CREATE,
869 	BPF_LINK_UPDATE,
870 	BPF_LINK_GET_FD_BY_ID,
871 	BPF_LINK_GET_NEXT_ID,
872 	BPF_ENABLE_STATS,
873 	BPF_ITER_CREATE,
874 	BPF_LINK_DETACH,
875 	BPF_PROG_BIND_MAP,
876 };
877 
878 enum bpf_map_type {
879 	BPF_MAP_TYPE_UNSPEC,
880 	BPF_MAP_TYPE_HASH,
881 	BPF_MAP_TYPE_ARRAY,
882 	BPF_MAP_TYPE_PROG_ARRAY,
883 	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
884 	BPF_MAP_TYPE_PERCPU_HASH,
885 	BPF_MAP_TYPE_PERCPU_ARRAY,
886 	BPF_MAP_TYPE_STACK_TRACE,
887 	BPF_MAP_TYPE_CGROUP_ARRAY,
888 	BPF_MAP_TYPE_LRU_HASH,
889 	BPF_MAP_TYPE_LRU_PERCPU_HASH,
890 	BPF_MAP_TYPE_LPM_TRIE,
891 	BPF_MAP_TYPE_ARRAY_OF_MAPS,
892 	BPF_MAP_TYPE_HASH_OF_MAPS,
893 	BPF_MAP_TYPE_DEVMAP,
894 	BPF_MAP_TYPE_SOCKMAP,
895 	BPF_MAP_TYPE_CPUMAP,
896 	BPF_MAP_TYPE_XSKMAP,
897 	BPF_MAP_TYPE_SOCKHASH,
898 	BPF_MAP_TYPE_CGROUP_STORAGE,
899 	BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
900 	BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
901 	BPF_MAP_TYPE_QUEUE,
902 	BPF_MAP_TYPE_STACK,
903 	BPF_MAP_TYPE_SK_STORAGE,
904 	BPF_MAP_TYPE_DEVMAP_HASH,
905 	BPF_MAP_TYPE_STRUCT_OPS,
906 	BPF_MAP_TYPE_RINGBUF,
907 	BPF_MAP_TYPE_INODE_STORAGE,
908 	BPF_MAP_TYPE_TASK_STORAGE,
909 };
910 
911 /* Note that tracing related programs such as
912  * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
913  * are not subject to a stable API since kernel internal data
914  * structures can change from release to release and may
915  * therefore break existing tracing BPF programs. Tracing BPF
916  * programs correspond to /a/ specific kernel which is to be
917  * analyzed, and not /a/ specific kernel /and/ all future ones.
918  */
919 enum bpf_prog_type {
920 	BPF_PROG_TYPE_UNSPEC,
921 	BPF_PROG_TYPE_SOCKET_FILTER,
922 	BPF_PROG_TYPE_KPROBE,
923 	BPF_PROG_TYPE_SCHED_CLS,
924 	BPF_PROG_TYPE_SCHED_ACT,
925 	BPF_PROG_TYPE_TRACEPOINT,
926 	BPF_PROG_TYPE_XDP,
927 	BPF_PROG_TYPE_PERF_EVENT,
928 	BPF_PROG_TYPE_CGROUP_SKB,
929 	BPF_PROG_TYPE_CGROUP_SOCK,
930 	BPF_PROG_TYPE_LWT_IN,
931 	BPF_PROG_TYPE_LWT_OUT,
932 	BPF_PROG_TYPE_LWT_XMIT,
933 	BPF_PROG_TYPE_SOCK_OPS,
934 	BPF_PROG_TYPE_SK_SKB,
935 	BPF_PROG_TYPE_CGROUP_DEVICE,
936 	BPF_PROG_TYPE_SK_MSG,
937 	BPF_PROG_TYPE_RAW_TRACEPOINT,
938 	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
939 	BPF_PROG_TYPE_LWT_SEG6LOCAL,
940 	BPF_PROG_TYPE_LIRC_MODE2,
941 	BPF_PROG_TYPE_SK_REUSEPORT,
942 	BPF_PROG_TYPE_FLOW_DISSECTOR,
943 	BPF_PROG_TYPE_CGROUP_SYSCTL,
944 	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
945 	BPF_PROG_TYPE_CGROUP_SOCKOPT,
946 	BPF_PROG_TYPE_TRACING,
947 	BPF_PROG_TYPE_STRUCT_OPS,
948 	BPF_PROG_TYPE_EXT,
949 	BPF_PROG_TYPE_LSM,
950 	BPF_PROG_TYPE_SK_LOOKUP,
951 	BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
952 };
953 
954 enum bpf_attach_type {
955 	BPF_CGROUP_INET_INGRESS,
956 	BPF_CGROUP_INET_EGRESS,
957 	BPF_CGROUP_INET_SOCK_CREATE,
958 	BPF_CGROUP_SOCK_OPS,
959 	BPF_SK_SKB_STREAM_PARSER,
960 	BPF_SK_SKB_STREAM_VERDICT,
961 	BPF_CGROUP_DEVICE,
962 	BPF_SK_MSG_VERDICT,
963 	BPF_CGROUP_INET4_BIND,
964 	BPF_CGROUP_INET6_BIND,
965 	BPF_CGROUP_INET4_CONNECT,
966 	BPF_CGROUP_INET6_CONNECT,
967 	BPF_CGROUP_INET4_POST_BIND,
968 	BPF_CGROUP_INET6_POST_BIND,
969 	BPF_CGROUP_UDP4_SENDMSG,
970 	BPF_CGROUP_UDP6_SENDMSG,
971 	BPF_LIRC_MODE2,
972 	BPF_FLOW_DISSECTOR,
973 	BPF_CGROUP_SYSCTL,
974 	BPF_CGROUP_UDP4_RECVMSG,
975 	BPF_CGROUP_UDP6_RECVMSG,
976 	BPF_CGROUP_GETSOCKOPT,
977 	BPF_CGROUP_SETSOCKOPT,
978 	BPF_TRACE_RAW_TP,
979 	BPF_TRACE_FENTRY,
980 	BPF_TRACE_FEXIT,
981 	BPF_MODIFY_RETURN,
982 	BPF_LSM_MAC,
983 	BPF_TRACE_ITER,
984 	BPF_CGROUP_INET4_GETPEERNAME,
985 	BPF_CGROUP_INET6_GETPEERNAME,
986 	BPF_CGROUP_INET4_GETSOCKNAME,
987 	BPF_CGROUP_INET6_GETSOCKNAME,
988 	BPF_XDP_DEVMAP,
989 	BPF_CGROUP_INET_SOCK_RELEASE,
990 	BPF_XDP_CPUMAP,
991 	BPF_SK_LOOKUP,
992 	BPF_XDP,
993 	BPF_SK_SKB_VERDICT,
994 	BPF_SK_REUSEPORT_SELECT,
995 	BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
996 	BPF_PERF_EVENT,
997 	__MAX_BPF_ATTACH_TYPE
998 };
999 
1000 #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
1001 
1002 enum bpf_link_type {
1003 	BPF_LINK_TYPE_UNSPEC = 0,
1004 	BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
1005 	BPF_LINK_TYPE_TRACING = 2,
1006 	BPF_LINK_TYPE_CGROUP = 3,
1007 	BPF_LINK_TYPE_ITER = 4,
1008 	BPF_LINK_TYPE_NETNS = 5,
1009 	BPF_LINK_TYPE_XDP = 6,
1010 	BPF_LINK_TYPE_PERF_EVENT = 7,
1011 
1012 	MAX_BPF_LINK_TYPE,
1013 };
1014 
1015 /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
1016  *
1017  * NONE(default): No further bpf programs allowed in the subtree.
1018  *
1019  * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
1020  * the program in this cgroup yields to sub-cgroup program.
1021  *
1022  * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
1023  * that cgroup program gets run in addition to the program in this cgroup.
1024  *
1025  * Only one program is allowed to be attached to a cgroup with
1026  * NONE or BPF_F_ALLOW_OVERRIDE flag.
1027  * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
1028  * release old program and attach the new one. Attach flags has to match.
1029  *
1030  * Multiple programs are allowed to be attached to a cgroup with
1031  * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
1032  * (those that were attached first, run first)
1033  * The programs of sub-cgroup are executed first, then programs of
1034  * this cgroup and then programs of parent cgroup.
1035  * When children program makes decision (like picking TCP CA or sock bind)
1036  * parent program has a chance to override it.
1037  *
1038  * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
1039  * programs for a cgroup. Though it's possible to replace an old program at
1040  * any position by also specifying BPF_F_REPLACE flag and position itself in
1041  * replace_bpf_fd attribute. Old program at this position will be released.
1042  *
1043  * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
1044  * A cgroup with NONE doesn't allow any programs in sub-cgroups.
1045  * Ex1:
1046  * cgrp1 (MULTI progs A, B) ->
1047  *    cgrp2 (OVERRIDE prog C) ->
1048  *      cgrp3 (MULTI prog D) ->
1049  *        cgrp4 (OVERRIDE prog E) ->
1050  *          cgrp5 (NONE prog F)
1051  * the event in cgrp5 triggers execution of F,D,A,B in that order.
1052  * if prog F is detached, the execution is E,D,A,B
1053  * if prog F and D are detached, the execution is E,A,B
1054  * if prog F, E and D are detached, the execution is C,A,B
1055  *
1056  * All eligible programs are executed regardless of return code from
1057  * earlier programs.
1058  */
1059 #define BPF_F_ALLOW_OVERRIDE	(1U << 0)
1060 #define BPF_F_ALLOW_MULTI	(1U << 1)
1061 #define BPF_F_REPLACE		(1U << 2)
1062 
1063 /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
1064  * verifier will perform strict alignment checking as if the kernel
1065  * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
1066  * and NET_IP_ALIGN defined to 2.
1067  */
1068 #define BPF_F_STRICT_ALIGNMENT	(1U << 0)
1069 
1070 /* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
1071  * verifier will allow any alignment whatsoever.  On platforms
1072  * with strict alignment requirements for loads ands stores (such
1073  * as sparc and mips) the verifier validates that all loads and
1074  * stores provably follow this requirement.  This flag turns that
1075  * checking and enforcement off.
1076  *
1077  * It is mostly used for testing when we want to validate the
1078  * context and memory access aspects of the verifier, but because
1079  * of an unaligned access the alignment check would trigger before
1080  * the one we are interested in.
1081  */
1082 #define BPF_F_ANY_ALIGNMENT	(1U << 1)
1083 
1084 /* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
1085  * Verifier does sub-register def/use analysis and identifies instructions whose
1086  * def only matters for low 32-bit, high 32-bit is never referenced later
1087  * through implicit zero extension. Therefore verifier notifies JIT back-ends
1088  * that it is safe to ignore clearing high 32-bit for these instructions. This
1089  * saves some back-ends a lot of code-gen. However such optimization is not
1090  * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
1091  * hence hasn't used verifier's analysis result. But, we really want to have a
1092  * way to be able to verify the correctness of the described optimization on
1093  * x86_64 on which testsuites are frequently exercised.
1094  *
1095  * So, this flag is introduced. Once it is set, verifier will randomize high
1096  * 32-bit for those instructions who has been identified as safe to ignore them.
1097  * Then, if verifier is not doing correct analysis, such randomization will
1098  * regress tests to expose bugs.
1099  */
1100 #define BPF_F_TEST_RND_HI32	(1U << 2)
1101 
1102 /* The verifier internal test flag. Behavior is undefined */
1103 #define BPF_F_TEST_STATE_FREQ	(1U << 3)
1104 
1105 /* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
1106  * restrict map and helper usage for such programs. Sleepable BPF programs can
1107  * only be attached to hooks where kernel execution context allows sleeping.
1108  * Such programs are allowed to use helpers that may sleep like
1109  * bpf_copy_from_user().
1110  */
1111 #define BPF_F_SLEEPABLE		(1U << 4)
1112 
1113 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
1114  * the following extensions:
1115  *
1116  * insn[0].src_reg:  BPF_PSEUDO_MAP_[FD|IDX]
1117  * insn[0].imm:      map fd or fd_idx
1118  * insn[1].imm:      0
1119  * insn[0].off:      0
1120  * insn[1].off:      0
1121  * ldimm64 rewrite:  address of map
1122  * verifier type:    CONST_PTR_TO_MAP
1123  */
1124 #define BPF_PSEUDO_MAP_FD	1
1125 #define BPF_PSEUDO_MAP_IDX	5
1126 
1127 /* insn[0].src_reg:  BPF_PSEUDO_MAP_[IDX_]VALUE
1128  * insn[0].imm:      map fd or fd_idx
1129  * insn[1].imm:      offset into value
1130  * insn[0].off:      0
1131  * insn[1].off:      0
1132  * ldimm64 rewrite:  address of map[0]+offset
1133  * verifier type:    PTR_TO_MAP_VALUE
1134  */
1135 #define BPF_PSEUDO_MAP_VALUE		2
1136 #define BPF_PSEUDO_MAP_IDX_VALUE	6
1137 
1138 /* insn[0].src_reg:  BPF_PSEUDO_BTF_ID
1139  * insn[0].imm:      kernel btd id of VAR
1140  * insn[1].imm:      0
1141  * insn[0].off:      0
1142  * insn[1].off:      0
1143  * ldimm64 rewrite:  address of the kernel variable
1144  * verifier type:    PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
1145  *                   is struct/union.
1146  */
1147 #define BPF_PSEUDO_BTF_ID	3
1148 /* insn[0].src_reg:  BPF_PSEUDO_FUNC
1149  * insn[0].imm:      insn offset to the func
1150  * insn[1].imm:      0
1151  * insn[0].off:      0
1152  * insn[1].off:      0
1153  * ldimm64 rewrite:  address of the function
1154  * verifier type:    PTR_TO_FUNC.
1155  */
1156 #define BPF_PSEUDO_FUNC		4
1157 
1158 /* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
1159  * offset to another bpf function
1160  */
1161 #define BPF_PSEUDO_CALL		1
1162 /* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,
1163  * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
1164  */
1165 #define BPF_PSEUDO_KFUNC_CALL	2
1166 
1167 /* flags for BPF_MAP_UPDATE_ELEM command */
1168 enum {
1169 	BPF_ANY		= 0, /* create new element or update existing */
1170 	BPF_NOEXIST	= 1, /* create new element if it didn't exist */
1171 	BPF_EXIST	= 2, /* update existing element */
1172 	BPF_F_LOCK	= 4, /* spin_lock-ed map_lookup/map_update */
1173 };
1174 
1175 /* flags for BPF_MAP_CREATE command */
1176 enum {
1177 	BPF_F_NO_PREALLOC	= (1U << 0),
1178 /* Instead of having one common LRU list in the
1179  * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
1180  * which can scale and perform better.
1181  * Note, the LRU nodes (including free nodes) cannot be moved
1182  * across different LRU lists.
1183  */
1184 	BPF_F_NO_COMMON_LRU	= (1U << 1),
1185 /* Specify numa node during map creation */
1186 	BPF_F_NUMA_NODE		= (1U << 2),
1187 
1188 /* Flags for accessing BPF object from syscall side. */
1189 	BPF_F_RDONLY		= (1U << 3),
1190 	BPF_F_WRONLY		= (1U << 4),
1191 
1192 /* Flag for stack_map, store build_id+offset instead of pointer */
1193 	BPF_F_STACK_BUILD_ID	= (1U << 5),
1194 
1195 /* Zero-initialize hash function seed. This should only be used for testing. */
1196 	BPF_F_ZERO_SEED		= (1U << 6),
1197 
1198 /* Flags for accessing BPF object from program side. */
1199 	BPF_F_RDONLY_PROG	= (1U << 7),
1200 	BPF_F_WRONLY_PROG	= (1U << 8),
1201 
1202 /* Clone map from listener for newly accepted socket */
1203 	BPF_F_CLONE		= (1U << 9),
1204 
1205 /* Enable memory-mapping BPF map */
1206 	BPF_F_MMAPABLE		= (1U << 10),
1207 
1208 /* Share perf_event among processes */
1209 	BPF_F_PRESERVE_ELEMS	= (1U << 11),
1210 
1211 /* Create a map that is suitable to be an inner map with dynamic max entries */
1212 	BPF_F_INNER_MAP		= (1U << 12),
1213 };
1214 
1215 /* Flags for BPF_PROG_QUERY. */
1216 
1217 /* Query effective (directly attached + inherited from ancestor cgroups)
1218  * programs that will be executed for events within a cgroup.
1219  * attach_flags with this flag are returned only for directly attached programs.
1220  */
1221 #define BPF_F_QUERY_EFFECTIVE	(1U << 0)
1222 
1223 /* Flags for BPF_PROG_TEST_RUN */
1224 
1225 /* If set, run the test on the cpu specified by bpf_attr.test.cpu */
1226 #define BPF_F_TEST_RUN_ON_CPU	(1U << 0)
1227 
1228 /* type for BPF_ENABLE_STATS */
1229 enum bpf_stats_type {
1230 	/* enabled run_time_ns and run_cnt */
1231 	BPF_STATS_RUN_TIME = 0,
1232 };
1233 
1234 enum bpf_stack_build_id_status {
1235 	/* user space need an empty entry to identify end of a trace */
1236 	BPF_STACK_BUILD_ID_EMPTY = 0,
1237 	/* with valid build_id and offset */
1238 	BPF_STACK_BUILD_ID_VALID = 1,
1239 	/* couldn't get build_id, fallback to ip */
1240 	BPF_STACK_BUILD_ID_IP = 2,
1241 };
1242 
1243 #define BPF_BUILD_ID_SIZE 20
1244 struct bpf_stack_build_id {
1245 	__s32		status;
1246 	unsigned char	build_id[BPF_BUILD_ID_SIZE];
1247 	union {
1248 		__u64	offset;
1249 		__u64	ip;
1250 	};
1251 };
1252 
1253 #define BPF_OBJ_NAME_LEN 16U
1254 
1255 union bpf_attr {
1256 	struct { /* anonymous struct used by BPF_MAP_CREATE command */
1257 		__u32	map_type;	/* one of enum bpf_map_type */
1258 		__u32	key_size;	/* size of key in bytes */
1259 		__u32	value_size;	/* size of value in bytes */
1260 		__u32	max_entries;	/* max number of entries in a map */
1261 		__u32	map_flags;	/* BPF_MAP_CREATE related
1262 					 * flags defined above.
1263 					 */
1264 		__u32	inner_map_fd;	/* fd pointing to the inner map */
1265 		__u32	numa_node;	/* numa node (effective only if
1266 					 * BPF_F_NUMA_NODE is set).
1267 					 */
1268 		char	map_name[BPF_OBJ_NAME_LEN];
1269 		__u32	map_ifindex;	/* ifindex of netdev to create on */
1270 		__u32	btf_fd;		/* fd pointing to a BTF type data */
1271 		__u32	btf_key_type_id;	/* BTF type_id of the key */
1272 		__u32	btf_value_type_id;	/* BTF type_id of the value */
1273 		__u32	btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
1274 						   * struct stored as the
1275 						   * map value
1276 						   */
1277 	};
1278 
1279 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
1280 		__u32		map_fd;
1281 		__aligned_u64	key;
1282 		union {
1283 			__aligned_u64 value;
1284 			__aligned_u64 next_key;
1285 		};
1286 		__u64		flags;
1287 	};
1288 
1289 	struct { /* struct used by BPF_MAP_*_BATCH commands */
1290 		__aligned_u64	in_batch;	/* start batch,
1291 						 * NULL to start from beginning
1292 						 */
1293 		__aligned_u64	out_batch;	/* output: next start batch */
1294 		__aligned_u64	keys;
1295 		__aligned_u64	values;
1296 		__u32		count;		/* input/output:
1297 						 * input: # of key/value
1298 						 * elements
1299 						 * output: # of filled elements
1300 						 */
1301 		__u32		map_fd;
1302 		__u64		elem_flags;
1303 		__u64		flags;
1304 	} batch;
1305 
1306 	struct { /* anonymous struct used by BPF_PROG_LOAD command */
1307 		__u32		prog_type;	/* one of enum bpf_prog_type */
1308 		__u32		insn_cnt;
1309 		__aligned_u64	insns;
1310 		__aligned_u64	license;
1311 		__u32		log_level;	/* verbosity level of verifier */
1312 		__u32		log_size;	/* size of user buffer */
1313 		__aligned_u64	log_buf;	/* user supplied buffer */
1314 		__u32		kern_version;	/* not used */
1315 		__u32		prog_flags;
1316 		char		prog_name[BPF_OBJ_NAME_LEN];
1317 		__u32		prog_ifindex;	/* ifindex of netdev to prep for */
1318 		/* For some prog types expected attach type must be known at
1319 		 * load time to verify attach type specific parts of prog
1320 		 * (context accesses, allowed helpers, etc).
1321 		 */
1322 		__u32		expected_attach_type;
1323 		__u32		prog_btf_fd;	/* fd pointing to BTF type data */
1324 		__u32		func_info_rec_size;	/* userspace bpf_func_info size */
1325 		__aligned_u64	func_info;	/* func info */
1326 		__u32		func_info_cnt;	/* number of bpf_func_info records */
1327 		__u32		line_info_rec_size;	/* userspace bpf_line_info size */
1328 		__aligned_u64	line_info;	/* line info */
1329 		__u32		line_info_cnt;	/* number of bpf_line_info records */
1330 		__u32		attach_btf_id;	/* in-kernel BTF type id to attach to */
1331 		union {
1332 			/* valid prog_fd to attach to bpf prog */
1333 			__u32		attach_prog_fd;
1334 			/* or valid module BTF object fd or 0 to attach to vmlinux */
1335 			__u32		attach_btf_obj_fd;
1336 		};
1337 		__u32		:32;		/* pad */
1338 		__aligned_u64	fd_array;	/* array of FDs */
1339 	};
1340 
1341 	struct { /* anonymous struct used by BPF_OBJ_* commands */
1342 		__aligned_u64	pathname;
1343 		__u32		bpf_fd;
1344 		__u32		file_flags;
1345 	};
1346 
1347 	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
1348 		__u32		target_fd;	/* container object to attach to */
1349 		__u32		attach_bpf_fd;	/* eBPF program to attach */
1350 		__u32		attach_type;
1351 		__u32		attach_flags;
1352 		__u32		replace_bpf_fd;	/* previously attached eBPF
1353 						 * program to replace if
1354 						 * BPF_F_REPLACE is used
1355 						 */
1356 	};
1357 
1358 	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
1359 		__u32		prog_fd;
1360 		__u32		retval;
1361 		__u32		data_size_in;	/* input: len of data_in */
1362 		__u32		data_size_out;	/* input/output: len of data_out
1363 						 *   returns ENOSPC if data_out
1364 						 *   is too small.
1365 						 */
1366 		__aligned_u64	data_in;
1367 		__aligned_u64	data_out;
1368 		__u32		repeat;
1369 		__u32		duration;
1370 		__u32		ctx_size_in;	/* input: len of ctx_in */
1371 		__u32		ctx_size_out;	/* input/output: len of ctx_out
1372 						 *   returns ENOSPC if ctx_out
1373 						 *   is too small.
1374 						 */
1375 		__aligned_u64	ctx_in;
1376 		__aligned_u64	ctx_out;
1377 		__u32		flags;
1378 		__u32		cpu;
1379 	} test;
1380 
1381 	struct { /* anonymous struct used by BPF_*_GET_*_ID */
1382 		union {
1383 			__u32		start_id;
1384 			__u32		prog_id;
1385 			__u32		map_id;
1386 			__u32		btf_id;
1387 			__u32		link_id;
1388 		};
1389 		__u32		next_id;
1390 		__u32		open_flags;
1391 	};
1392 
1393 	struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
1394 		__u32		bpf_fd;
1395 		__u32		info_len;
1396 		__aligned_u64	info;
1397 	} info;
1398 
1399 	struct { /* anonymous struct used by BPF_PROG_QUERY command */
1400 		__u32		target_fd;	/* container object to query */
1401 		__u32		attach_type;
1402 		__u32		query_flags;
1403 		__u32		attach_flags;
1404 		__aligned_u64	prog_ids;
1405 		__u32		prog_cnt;
1406 	} query;
1407 
1408 	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
1409 		__u64 name;
1410 		__u32 prog_fd;
1411 	} raw_tracepoint;
1412 
1413 	struct { /* anonymous struct for BPF_BTF_LOAD */
1414 		__aligned_u64	btf;
1415 		__aligned_u64	btf_log_buf;
1416 		__u32		btf_size;
1417 		__u32		btf_log_size;
1418 		__u32		btf_log_level;
1419 	};
1420 
1421 	struct {
1422 		__u32		pid;		/* input: pid */
1423 		__u32		fd;		/* input: fd */
1424 		__u32		flags;		/* input: flags */
1425 		__u32		buf_len;	/* input/output: buf len */
1426 		__aligned_u64	buf;		/* input/output:
1427 						 *   tp_name for tracepoint
1428 						 *   symbol for kprobe
1429 						 *   filename for uprobe
1430 						 */
1431 		__u32		prog_id;	/* output: prod_id */
1432 		__u32		fd_type;	/* output: BPF_FD_TYPE_* */
1433 		__u64		probe_offset;	/* output: probe_offset */
1434 		__u64		probe_addr;	/* output: probe_addr */
1435 	} task_fd_query;
1436 
1437 	struct { /* struct used by BPF_LINK_CREATE command */
1438 		__u32		prog_fd;	/* eBPF program to attach */
1439 		union {
1440 			__u32		target_fd;	/* object to attach to */
1441 			__u32		target_ifindex; /* target ifindex */
1442 		};
1443 		__u32		attach_type;	/* attach type */
1444 		__u32		flags;		/* extra flags */
1445 		union {
1446 			__u32		target_btf_id;	/* btf_id of target to attach to */
1447 			struct {
1448 				__aligned_u64	iter_info;	/* extra bpf_iter_link_info */
1449 				__u32		iter_info_len;	/* iter_info length */
1450 			};
1451 			struct {
1452 				/* black box user-provided value passed through
1453 				 * to BPF program at the execution time and
1454 				 * accessible through bpf_get_attach_cookie() BPF helper
1455 				 */
1456 				__u64		bpf_cookie;
1457 			} perf_event;
1458 		};
1459 	} link_create;
1460 
1461 	struct { /* struct used by BPF_LINK_UPDATE command */
1462 		__u32		link_fd;	/* link fd */
1463 		/* new program fd to update link with */
1464 		__u32		new_prog_fd;
1465 		__u32		flags;		/* extra flags */
1466 		/* expected link's program fd; is specified only if
1467 		 * BPF_F_REPLACE flag is set in flags */
1468 		__u32		old_prog_fd;
1469 	} link_update;
1470 
1471 	struct {
1472 		__u32		link_fd;
1473 	} link_detach;
1474 
1475 	struct { /* struct used by BPF_ENABLE_STATS command */
1476 		__u32		type;
1477 	} enable_stats;
1478 
1479 	struct { /* struct used by BPF_ITER_CREATE command */
1480 		__u32		link_fd;
1481 		__u32		flags;
1482 	} iter_create;
1483 
1484 	struct { /* struct used by BPF_PROG_BIND_MAP command */
1485 		__u32		prog_fd;
1486 		__u32		map_fd;
1487 		__u32		flags;		/* extra flags */
1488 	} prog_bind_map;
1489 
1490 } __attribute__((aligned(8)));
1491 
1492 /* The description below is an attempt at providing documentation to eBPF
1493  * developers about the multiple available eBPF helper functions. It can be
1494  * parsed and used to produce a manual page. The workflow is the following,
1495  * and requires the rst2man utility:
1496  *
1497  *     $ ./scripts/bpf_doc.py \
1498  *             --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
1499  *     $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
1500  *     $ man /tmp/bpf-helpers.7
1501  *
1502  * Note that in order to produce this external documentation, some RST
1503  * formatting is used in the descriptions to get "bold" and "italics" in
1504  * manual pages. Also note that the few trailing white spaces are
1505  * intentional, removing them would break paragraphs for rst2man.
1506  *
1507  * Start of BPF helper function descriptions:
1508  *
1509  * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
1510  * 	Description
1511  * 		Perform a lookup in *map* for an entry associated to *key*.
1512  * 	Return
1513  * 		Map value associated to *key*, or **NULL** if no entry was
1514  * 		found.
1515  *
1516  * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
1517  * 	Description
1518  * 		Add or update the value of the entry associated to *key* in
1519  * 		*map* with *value*. *flags* is one of:
1520  *
1521  * 		**BPF_NOEXIST**
1522  * 			The entry for *key* must not exist in the map.
1523  * 		**BPF_EXIST**
1524  * 			The entry for *key* must already exist in the map.
1525  * 		**BPF_ANY**
1526  * 			No condition on the existence of the entry for *key*.
1527  *
1528  * 		Flag value **BPF_NOEXIST** cannot be used for maps of types
1529  * 		**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
1530  * 		elements always exist), the helper would return an error.
1531  * 	Return
1532  * 		0 on success, or a negative error in case of failure.
1533  *
1534  * long bpf_map_delete_elem(struct bpf_map *map, const void *key)
1535  * 	Description
1536  * 		Delete entry with *key* from *map*.
1537  * 	Return
1538  * 		0 on success, or a negative error in case of failure.
1539  *
1540  * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
1541  * 	Description
1542  * 		For tracing programs, safely attempt to read *size* bytes from
1543  * 		kernel space address *unsafe_ptr* and store the data in *dst*.
1544  *
1545  * 		Generally, use **bpf_probe_read_user**\ () or
1546  * 		**bpf_probe_read_kernel**\ () instead.
1547  * 	Return
1548  * 		0 on success, or a negative error in case of failure.
1549  *
1550  * u64 bpf_ktime_get_ns(void)
1551  * 	Description
1552  * 		Return the time elapsed since system boot, in nanoseconds.
1553  * 		Does not include time the system was suspended.
1554  * 		See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
1555  * 	Return
1556  * 		Current *ktime*.
1557  *
1558  * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
1559  * 	Description
1560  * 		This helper is a "printk()-like" facility for debugging. It
1561  * 		prints a message defined by format *fmt* (of size *fmt_size*)
1562  * 		to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
1563  * 		available. It can take up to three additional **u64**
1564  * 		arguments (as an eBPF helpers, the total number of arguments is
1565  * 		limited to five).
1566  *
1567  * 		Each time the helper is called, it appends a line to the trace.
1568  * 		Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
1569  * 		open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
1570  * 		The format of the trace is customizable, and the exact output
1571  * 		one will get depends on the options set in
1572  * 		*\/sys/kernel/debug/tracing/trace_options* (see also the
1573  * 		*README* file under the same directory). However, it usually
1574  * 		defaults to something like:
1575  *
1576  * 		::
1577  *
1578  * 			telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
1579  *
1580  * 		In the above:
1581  *
1582  * 			* ``telnet`` is the name of the current task.
1583  * 			* ``470`` is the PID of the current task.
1584  * 			* ``001`` is the CPU number on which the task is
1585  * 			  running.
1586  * 			* In ``.N..``, each character refers to a set of
1587  * 			  options (whether irqs are enabled, scheduling
1588  * 			  options, whether hard/softirqs are running, level of
1589  * 			  preempt_disabled respectively). **N** means that
1590  * 			  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
1591  * 			  are set.
1592  * 			* ``419421.045894`` is a timestamp.
1593  * 			* ``0x00000001`` is a fake value used by BPF for the
1594  * 			  instruction pointer register.
1595  * 			* ``<formatted msg>`` is the message formatted with
1596  * 			  *fmt*.
1597  *
1598  * 		The conversion specifiers supported by *fmt* are similar, but
1599  * 		more limited than for printk(). They are **%d**, **%i**,
1600  * 		**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
1601  * 		**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
1602  * 		of field, padding with zeroes, etc.) is available, and the
1603  * 		helper will return **-EINVAL** (but print nothing) if it
1604  * 		encounters an unknown specifier.
1605  *
1606  * 		Also, note that **bpf_trace_printk**\ () is slow, and should
1607  * 		only be used for debugging purposes. For this reason, a notice
1608  * 		block (spanning several lines) is printed to kernel logs and
1609  * 		states that the helper should not be used "for production use"
1610  * 		the first time this helper is used (or more precisely, when
1611  * 		**trace_printk**\ () buffers are allocated). For passing values
1612  * 		to user space, perf events should be preferred.
1613  * 	Return
1614  * 		The number of bytes written to the buffer, or a negative error
1615  * 		in case of failure.
1616  *
1617  * u32 bpf_get_prandom_u32(void)
1618  * 	Description
1619  * 		Get a pseudo-random number.
1620  *
1621  * 		From a security point of view, this helper uses its own
1622  * 		pseudo-random internal state, and cannot be used to infer the
1623  * 		seed of other random functions in the kernel. However, it is
1624  * 		essential to note that the generator used by the helper is not
1625  * 		cryptographically secure.
1626  * 	Return
1627  * 		A random 32-bit unsigned value.
1628  *
1629  * u32 bpf_get_smp_processor_id(void)
1630  * 	Description
1631  * 		Get the SMP (symmetric multiprocessing) processor id. Note that
1632  * 		all programs run with preemption disabled, which means that the
1633  * 		SMP processor id is stable during all the execution of the
1634  * 		program.
1635  * 	Return
1636  * 		The SMP id of the processor running the program.
1637  *
1638  * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
1639  * 	Description
1640  * 		Store *len* bytes from address *from* into the packet
1641  * 		associated to *skb*, at *offset*. *flags* are a combination of
1642  * 		**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
1643  * 		checksum for the packet after storing the bytes) and
1644  * 		**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
1645  * 		**->swhash** and *skb*\ **->l4hash** to 0).
1646  *
1647  * 		A call to this helper is susceptible to change the underlying
1648  * 		packet buffer. Therefore, at load time, all checks on pointers
1649  * 		previously done by the verifier are invalidated and must be
1650  * 		performed again, if the helper is used in combination with
1651  * 		direct packet access.
1652  * 	Return
1653  * 		0 on success, or a negative error in case of failure.
1654  *
1655  * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
1656  * 	Description
1657  * 		Recompute the layer 3 (e.g. IP) checksum for the packet
1658  * 		associated to *skb*. Computation is incremental, so the helper
1659  * 		must know the former value of the header field that was
1660  * 		modified (*from*), the new value of this field (*to*), and the
1661  * 		number of bytes (2 or 4) for this field, stored in *size*.
1662  * 		Alternatively, it is possible to store the difference between
1663  * 		the previous and the new values of the header field in *to*, by
1664  * 		setting *from* and *size* to 0. For both methods, *offset*
1665  * 		indicates the location of the IP checksum within the packet.
1666  *
1667  * 		This helper works in combination with **bpf_csum_diff**\ (),
1668  * 		which does not update the checksum in-place, but offers more
1669  * 		flexibility and can handle sizes larger than 2 or 4 for the
1670  * 		checksum to update.
1671  *
1672  * 		A call to this helper is susceptible to change the underlying
1673  * 		packet buffer. Therefore, at load time, all checks on pointers
1674  * 		previously done by the verifier are invalidated and must be
1675  * 		performed again, if the helper is used in combination with
1676  * 		direct packet access.
1677  * 	Return
1678  * 		0 on success, or a negative error in case of failure.
1679  *
1680  * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
1681  * 	Description
1682  * 		Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
1683  * 		packet associated to *skb*. Computation is incremental, so the
1684  * 		helper must know the former value of the header field that was
1685  * 		modified (*from*), the new value of this field (*to*), and the
1686  * 		number of bytes (2 or 4) for this field, stored on the lowest
1687  * 		four bits of *flags*. Alternatively, it is possible to store
1688  * 		the difference between the previous and the new values of the
1689  * 		header field in *to*, by setting *from* and the four lowest
1690  * 		bits of *flags* to 0. For both methods, *offset* indicates the
1691  * 		location of the IP checksum within the packet. In addition to
1692  * 		the size of the field, *flags* can be added (bitwise OR) actual
1693  * 		flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
1694  * 		untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
1695  * 		for updates resulting in a null checksum the value is set to
1696  * 		**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
1697  * 		the checksum is to be computed against a pseudo-header.
1698  *
1699  * 		This helper works in combination with **bpf_csum_diff**\ (),
1700  * 		which does not update the checksum in-place, but offers more
1701  * 		flexibility and can handle sizes larger than 2 or 4 for the
1702  * 		checksum to update.
1703  *
1704  * 		A call to this helper is susceptible to change the underlying
1705  * 		packet buffer. Therefore, at load time, all checks on pointers
1706  * 		previously done by the verifier are invalidated and must be
1707  * 		performed again, if the helper is used in combination with
1708  * 		direct packet access.
1709  * 	Return
1710  * 		0 on success, or a negative error in case of failure.
1711  *
1712  * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
1713  * 	Description
1714  * 		This special helper is used to trigger a "tail call", or in
1715  * 		other words, to jump into another eBPF program. The same stack
1716  * 		frame is used (but values on stack and in registers for the
1717  * 		caller are not accessible to the callee). This mechanism allows
1718  * 		for program chaining, either for raising the maximum number of
1719  * 		available eBPF instructions, or to execute given programs in
1720  * 		conditional blocks. For security reasons, there is an upper
1721  * 		limit to the number of successive tail calls that can be
1722  * 		performed.
1723  *
1724  * 		Upon call of this helper, the program attempts to jump into a
1725  * 		program referenced at index *index* in *prog_array_map*, a
1726  * 		special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
1727  * 		*ctx*, a pointer to the context.
1728  *
1729  * 		If the call succeeds, the kernel immediately runs the first
1730  * 		instruction of the new program. This is not a function call,
1731  * 		and it never returns to the previous program. If the call
1732  * 		fails, then the helper has no effect, and the caller continues
1733  * 		to run its subsequent instructions. A call can fail if the
1734  * 		destination program for the jump does not exist (i.e. *index*
1735  * 		is superior to the number of entries in *prog_array_map*), or
1736  * 		if the maximum number of tail calls has been reached for this
1737  * 		chain of programs. This limit is defined in the kernel by the
1738  * 		macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
1739  * 		which is currently set to 32.
1740  * 	Return
1741  * 		0 on success, or a negative error in case of failure.
1742  *
1743  * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
1744  * 	Description
1745  * 		Clone and redirect the packet associated to *skb* to another
1746  * 		net device of index *ifindex*. Both ingress and egress
1747  * 		interfaces can be used for redirection. The **BPF_F_INGRESS**
1748  * 		value in *flags* is used to make the distinction (ingress path
1749  * 		is selected if the flag is present, egress path otherwise).
1750  * 		This is the only flag supported for now.
1751  *
1752  * 		In comparison with **bpf_redirect**\ () helper,
1753  * 		**bpf_clone_redirect**\ () has the associated cost of
1754  * 		duplicating the packet buffer, but this can be executed out of
1755  * 		the eBPF program. Conversely, **bpf_redirect**\ () is more
1756  * 		efficient, but it is handled through an action code where the
1757  * 		redirection happens only after the eBPF program has returned.
1758  *
1759  * 		A call to this helper is susceptible to change the underlying
1760  * 		packet buffer. Therefore, at load time, all checks on pointers
1761  * 		previously done by the verifier are invalidated and must be
1762  * 		performed again, if the helper is used in combination with
1763  * 		direct packet access.
1764  * 	Return
1765  * 		0 on success, or a negative error in case of failure. Positive
1766  * 		error indicates a potential drop or congestion in the target
1767  * 		device. The particular positive error codes are not defined.
1768  *
1769  * u64 bpf_get_current_pid_tgid(void)
1770  * 	Return
1771  * 		A 64-bit integer containing the current tgid and pid, and
1772  * 		created as such:
1773  * 		*current_task*\ **->tgid << 32 \|**
1774  * 		*current_task*\ **->pid**.
1775  *
1776  * u64 bpf_get_current_uid_gid(void)
1777  * 	Return
1778  * 		A 64-bit integer containing the current GID and UID, and
1779  * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
1780  *
1781  * long bpf_get_current_comm(void *buf, u32 size_of_buf)
1782  * 	Description
1783  * 		Copy the **comm** attribute of the current task into *buf* of
1784  * 		*size_of_buf*. The **comm** attribute contains the name of
1785  * 		the executable (excluding the path) for the current task. The
1786  * 		*size_of_buf* must be strictly positive. On success, the
1787  * 		helper makes sure that the *buf* is NUL-terminated. On failure,
1788  * 		it is filled with zeroes.
1789  * 	Return
1790  * 		0 on success, or a negative error in case of failure.
1791  *
1792  * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
1793  * 	Description
1794  * 		Retrieve the classid for the current task, i.e. for the net_cls
1795  * 		cgroup to which *skb* belongs.
1796  *
1797  * 		This helper can be used on TC egress path, but not on ingress.
1798  *
1799  * 		The net_cls cgroup provides an interface to tag network packets
1800  * 		based on a user-provided identifier for all traffic coming from
1801  * 		the tasks belonging to the related cgroup. See also the related
1802  * 		kernel documentation, available from the Linux sources in file
1803  * 		*Documentation/admin-guide/cgroup-v1/net_cls.rst*.
1804  *
1805  * 		The Linux kernel has two versions for cgroups: there are
1806  * 		cgroups v1 and cgroups v2. Both are available to users, who can
1807  * 		use a mixture of them, but note that the net_cls cgroup is for
1808  * 		cgroup v1 only. This makes it incompatible with BPF programs
1809  * 		run on cgroups, which is a cgroup-v2-only feature (a socket can
1810  * 		only hold data for one version of cgroups at a time).
1811  *
1812  * 		This helper is only available is the kernel was compiled with
1813  * 		the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
1814  * 		"**y**" or to "**m**".
1815  * 	Return
1816  * 		The classid, or 0 for the default unconfigured classid.
1817  *
1818  * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
1819  * 	Description
1820  * 		Push a *vlan_tci* (VLAN tag control information) of protocol
1821  * 		*vlan_proto* to the packet associated to *skb*, then update
1822  * 		the checksum. Note that if *vlan_proto* is different from
1823  * 		**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
1824  * 		be **ETH_P_8021Q**.
1825  *
1826  * 		A call to this helper is susceptible to change the underlying
1827  * 		packet buffer. Therefore, at load time, all checks on pointers
1828  * 		previously done by the verifier are invalidated and must be
1829  * 		performed again, if the helper is used in combination with
1830  * 		direct packet access.
1831  * 	Return
1832  * 		0 on success, or a negative error in case of failure.
1833  *
1834  * long bpf_skb_vlan_pop(struct sk_buff *skb)
1835  * 	Description
1836  * 		Pop a VLAN header from the packet associated to *skb*.
1837  *
1838  * 		A call to this helper is susceptible to change the underlying
1839  * 		packet buffer. Therefore, at load time, all checks on pointers
1840  * 		previously done by the verifier are invalidated and must be
1841  * 		performed again, if the helper is used in combination with
1842  * 		direct packet access.
1843  * 	Return
1844  * 		0 on success, or a negative error in case of failure.
1845  *
1846  * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1847  * 	Description
1848  * 		Get tunnel metadata. This helper takes a pointer *key* to an
1849  * 		empty **struct bpf_tunnel_key** of **size**, that will be
1850  * 		filled with tunnel metadata for the packet associated to *skb*.
1851  * 		The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
1852  * 		indicates that the tunnel is based on IPv6 protocol instead of
1853  * 		IPv4.
1854  *
1855  * 		The **struct bpf_tunnel_key** is an object that generalizes the
1856  * 		principal parameters used by various tunneling protocols into a
1857  * 		single struct. This way, it can be used to easily make a
1858  * 		decision based on the contents of the encapsulation header,
1859  * 		"summarized" in this struct. In particular, it holds the IP
1860  * 		address of the remote end (IPv4 or IPv6, depending on the case)
1861  * 		in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
1862  * 		this struct exposes the *key*\ **->tunnel_id**, which is
1863  * 		generally mapped to a VNI (Virtual Network Identifier), making
1864  * 		it programmable together with the **bpf_skb_set_tunnel_key**\
1865  * 		() helper.
1866  *
1867  * 		Let's imagine that the following code is part of a program
1868  * 		attached to the TC ingress interface, on one end of a GRE
1869  * 		tunnel, and is supposed to filter out all messages coming from
1870  * 		remote ends with IPv4 address other than 10.0.0.1:
1871  *
1872  * 		::
1873  *
1874  * 			int ret;
1875  * 			struct bpf_tunnel_key key = {};
1876  *
1877  * 			ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
1878  * 			if (ret < 0)
1879  * 				return TC_ACT_SHOT;	// drop packet
1880  *
1881  * 			if (key.remote_ipv4 != 0x0a000001)
1882  * 				return TC_ACT_SHOT;	// drop packet
1883  *
1884  * 			return TC_ACT_OK;		// accept packet
1885  *
1886  * 		This interface can also be used with all encapsulation devices
1887  * 		that can operate in "collect metadata" mode: instead of having
1888  * 		one network device per specific configuration, the "collect
1889  * 		metadata" mode only requires a single device where the
1890  * 		configuration can be extracted from this helper.
1891  *
1892  * 		This can be used together with various tunnels such as VXLan,
1893  * 		Geneve, GRE or IP in IP (IPIP).
1894  * 	Return
1895  * 		0 on success, or a negative error in case of failure.
1896  *
1897  * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1898  * 	Description
1899  * 		Populate tunnel metadata for packet associated to *skb.* The
1900  * 		tunnel metadata is set to the contents of *key*, of *size*. The
1901  * 		*flags* can be set to a combination of the following values:
1902  *
1903  * 		**BPF_F_TUNINFO_IPV6**
1904  * 			Indicate that the tunnel is based on IPv6 protocol
1905  * 			instead of IPv4.
1906  * 		**BPF_F_ZERO_CSUM_TX**
1907  * 			For IPv4 packets, add a flag to tunnel metadata
1908  * 			indicating that checksum computation should be skipped
1909  * 			and checksum set to zeroes.
1910  * 		**BPF_F_DONT_FRAGMENT**
1911  * 			Add a flag to tunnel metadata indicating that the
1912  * 			packet should not be fragmented.
1913  * 		**BPF_F_SEQ_NUMBER**
1914  * 			Add a flag to tunnel metadata indicating that a
1915  * 			sequence number should be added to tunnel header before
1916  * 			sending the packet. This flag was added for GRE
1917  * 			encapsulation, but might be used with other protocols
1918  * 			as well in the future.
1919  *
1920  * 		Here is a typical usage on the transmit path:
1921  *
1922  * 		::
1923  *
1924  * 			struct bpf_tunnel_key key;
1925  * 			     populate key ...
1926  * 			bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
1927  * 			bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
1928  *
1929  * 		See also the description of the **bpf_skb_get_tunnel_key**\ ()
1930  * 		helper for additional information.
1931  * 	Return
1932  * 		0 on success, or a negative error in case of failure.
1933  *
1934  * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
1935  * 	Description
1936  * 		Read the value of a perf event counter. This helper relies on a
1937  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
1938  * 		the perf event counter is selected when *map* is updated with
1939  * 		perf event file descriptors. The *map* is an array whose size
1940  * 		is the number of available CPUs, and each cell contains a value
1941  * 		relative to one CPU. The value to retrieve is indicated by
1942  * 		*flags*, that contains the index of the CPU to look up, masked
1943  * 		with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1944  * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
1945  * 		current CPU should be retrieved.
1946  *
1947  * 		Note that before Linux 4.13, only hardware perf event can be
1948  * 		retrieved.
1949  *
1950  * 		Also, be aware that the newer helper
1951  * 		**bpf_perf_event_read_value**\ () is recommended over
1952  * 		**bpf_perf_event_read**\ () in general. The latter has some ABI
1953  * 		quirks where error and counter value are used as a return code
1954  * 		(which is wrong to do since ranges may overlap). This issue is
1955  * 		fixed with **bpf_perf_event_read_value**\ (), which at the same
1956  * 		time provides more features over the **bpf_perf_event_read**\
1957  * 		() interface. Please refer to the description of
1958  * 		**bpf_perf_event_read_value**\ () for details.
1959  * 	Return
1960  * 		The value of the perf event counter read from the map, or a
1961  * 		negative error code in case of failure.
1962  *
1963  * long bpf_redirect(u32 ifindex, u64 flags)
1964  * 	Description
1965  * 		Redirect the packet to another net device of index *ifindex*.
1966  * 		This helper is somewhat similar to **bpf_clone_redirect**\
1967  * 		(), except that the packet is not cloned, which provides
1968  * 		increased performance.
1969  *
1970  * 		Except for XDP, both ingress and egress interfaces can be used
1971  * 		for redirection. The **BPF_F_INGRESS** value in *flags* is used
1972  * 		to make the distinction (ingress path is selected if the flag
1973  * 		is present, egress path otherwise). Currently, XDP only
1974  * 		supports redirection to the egress interface, and accepts no
1975  * 		flag at all.
1976  *
1977  * 		The same effect can also be attained with the more generic
1978  * 		**bpf_redirect_map**\ (), which uses a BPF map to store the
1979  * 		redirect target instead of providing it directly to the helper.
1980  * 	Return
1981  * 		For XDP, the helper returns **XDP_REDIRECT** on success or
1982  * 		**XDP_ABORTED** on error. For other program types, the values
1983  * 		are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
1984  * 		error.
1985  *
1986  * u32 bpf_get_route_realm(struct sk_buff *skb)
1987  * 	Description
1988  * 		Retrieve the realm or the route, that is to say the
1989  * 		**tclassid** field of the destination for the *skb*. The
1990  * 		identifier retrieved is a user-provided tag, similar to the
1991  * 		one used with the net_cls cgroup (see description for
1992  * 		**bpf_get_cgroup_classid**\ () helper), but here this tag is
1993  * 		held by a route (a destination entry), not by a task.
1994  *
1995  * 		Retrieving this identifier works with the clsact TC egress hook
1996  * 		(see also **tc-bpf(8)**), or alternatively on conventional
1997  * 		classful egress qdiscs, but not on TC ingress path. In case of
1998  * 		clsact TC egress hook, this has the advantage that, internally,
1999  * 		the destination entry has not been dropped yet in the transmit
2000  * 		path. Therefore, the destination entry does not need to be
2001  * 		artificially held via **netif_keep_dst**\ () for a classful
2002  * 		qdisc until the *skb* is freed.
2003  *
2004  * 		This helper is available only if the kernel was compiled with
2005  * 		**CONFIG_IP_ROUTE_CLASSID** configuration option.
2006  * 	Return
2007  * 		The realm of the route for the packet associated to *skb*, or 0
2008  * 		if none was found.
2009  *
2010  * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
2011  * 	Description
2012  * 		Write raw *data* blob into a special BPF perf event held by
2013  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
2014  * 		event must have the following attributes: **PERF_SAMPLE_RAW**
2015  * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
2016  * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
2017  *
2018  * 		The *flags* are used to indicate the index in *map* for which
2019  * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
2020  * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
2021  * 		to indicate that the index of the current CPU core should be
2022  * 		used.
2023  *
2024  * 		The value to write, of *size*, is passed through eBPF stack and
2025  * 		pointed by *data*.
2026  *
2027  * 		The context of the program *ctx* needs also be passed to the
2028  * 		helper.
2029  *
2030  * 		On user space, a program willing to read the values needs to
2031  * 		call **perf_event_open**\ () on the perf event (either for
2032  * 		one or for all CPUs) and to store the file descriptor into the
2033  * 		*map*. This must be done before the eBPF program can send data
2034  * 		into it. An example is available in file
2035  * 		*samples/bpf/trace_output_user.c* in the Linux kernel source
2036  * 		tree (the eBPF program counterpart is in
2037  * 		*samples/bpf/trace_output_kern.c*).
2038  *
2039  * 		**bpf_perf_event_output**\ () achieves better performance
2040  * 		than **bpf_trace_printk**\ () for sharing data with user
2041  * 		space, and is much better suitable for streaming data from eBPF
2042  * 		programs.
2043  *
2044  * 		Note that this helper is not restricted to tracing use cases
2045  * 		and can be used with programs attached to TC or XDP as well,
2046  * 		where it allows for passing data to user space listeners. Data
2047  * 		can be:
2048  *
2049  * 		* Only custom structs,
2050  * 		* Only the packet payload, or
2051  * 		* A combination of both.
2052  * 	Return
2053  * 		0 on success, or a negative error in case of failure.
2054  *
2055  * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
2056  * 	Description
2057  * 		This helper was provided as an easy way to load data from a
2058  * 		packet. It can be used to load *len* bytes from *offset* from
2059  * 		the packet associated to *skb*, into the buffer pointed by
2060  * 		*to*.
2061  *
2062  * 		Since Linux 4.7, usage of this helper has mostly been replaced
2063  * 		by "direct packet access", enabling packet data to be
2064  * 		manipulated with *skb*\ **->data** and *skb*\ **->data_end**
2065  * 		pointing respectively to the first byte of packet data and to
2066  * 		the byte after the last byte of packet data. However, it
2067  * 		remains useful if one wishes to read large quantities of data
2068  * 		at once from a packet into the eBPF stack.
2069  * 	Return
2070  * 		0 on success, or a negative error in case of failure.
2071  *
2072  * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
2073  * 	Description
2074  * 		Walk a user or a kernel stack and return its id. To achieve
2075  * 		this, the helper needs *ctx*, which is a pointer to the context
2076  * 		on which the tracing program is executed, and a pointer to a
2077  * 		*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
2078  *
2079  * 		The last argument, *flags*, holds the number of stack frames to
2080  * 		skip (from 0 to 255), masked with
2081  * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2082  * 		a combination of the following flags:
2083  *
2084  * 		**BPF_F_USER_STACK**
2085  * 			Collect a user space stack instead of a kernel stack.
2086  * 		**BPF_F_FAST_STACK_CMP**
2087  * 			Compare stacks by hash only.
2088  * 		**BPF_F_REUSE_STACKID**
2089  * 			If two different stacks hash into the same *stackid*,
2090  * 			discard the old one.
2091  *
2092  * 		The stack id retrieved is a 32 bit long integer handle which
2093  * 		can be further combined with other data (including other stack
2094  * 		ids) and used as a key into maps. This can be useful for
2095  * 		generating a variety of graphs (such as flame graphs or off-cpu
2096  * 		graphs).
2097  *
2098  * 		For walking a stack, this helper is an improvement over
2099  * 		**bpf_probe_read**\ (), which can be used with unrolled loops
2100  * 		but is not efficient and consumes a lot of eBPF instructions.
2101  * 		Instead, **bpf_get_stackid**\ () can collect up to
2102  * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
2103  * 		this limit can be controlled with the **sysctl** program, and
2104  * 		that it should be manually increased in order to profile long
2105  * 		user stacks (such as stacks for Java programs). To do so, use:
2106  *
2107  * 		::
2108  *
2109  * 			# sysctl kernel.perf_event_max_stack=<new value>
2110  * 	Return
2111  * 		The positive or null stack id on success, or a negative error
2112  * 		in case of failure.
2113  *
2114  * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
2115  * 	Description
2116  * 		Compute a checksum difference, from the raw buffer pointed by
2117  * 		*from*, of length *from_size* (that must be a multiple of 4),
2118  * 		towards the raw buffer pointed by *to*, of size *to_size*
2119  * 		(same remark). An optional *seed* can be added to the value
2120  * 		(this can be cascaded, the seed may come from a previous call
2121  * 		to the helper).
2122  *
2123  * 		This is flexible enough to be used in several ways:
2124  *
2125  * 		* With *from_size* == 0, *to_size* > 0 and *seed* set to
2126  * 		  checksum, it can be used when pushing new data.
2127  * 		* With *from_size* > 0, *to_size* == 0 and *seed* set to
2128  * 		  checksum, it can be used when removing data from a packet.
2129  * 		* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
2130  * 		  can be used to compute a diff. Note that *from_size* and
2131  * 		  *to_size* do not need to be equal.
2132  *
2133  * 		This helper can be used in combination with
2134  * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
2135  * 		which one can feed in the difference computed with
2136  * 		**bpf_csum_diff**\ ().
2137  * 	Return
2138  * 		The checksum result, or a negative error code in case of
2139  * 		failure.
2140  *
2141  * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2142  * 	Description
2143  * 		Retrieve tunnel options metadata for the packet associated to
2144  * 		*skb*, and store the raw tunnel option data to the buffer *opt*
2145  * 		of *size*.
2146  *
2147  * 		This helper can be used with encapsulation devices that can
2148  * 		operate in "collect metadata" mode (please refer to the related
2149  * 		note in the description of **bpf_skb_get_tunnel_key**\ () for
2150  * 		more details). A particular example where this can be used is
2151  * 		in combination with the Geneve encapsulation protocol, where it
2152  * 		allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
2153  * 		and retrieving arbitrary TLVs (Type-Length-Value headers) from
2154  * 		the eBPF program. This allows for full customization of these
2155  * 		headers.
2156  * 	Return
2157  * 		The size of the option data retrieved.
2158  *
2159  * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2160  * 	Description
2161  * 		Set tunnel options metadata for the packet associated to *skb*
2162  * 		to the option data contained in the raw buffer *opt* of *size*.
2163  *
2164  * 		See also the description of the **bpf_skb_get_tunnel_opt**\ ()
2165  * 		helper for additional information.
2166  * 	Return
2167  * 		0 on success, or a negative error in case of failure.
2168  *
2169  * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
2170  * 	Description
2171  * 		Change the protocol of the *skb* to *proto*. Currently
2172  * 		supported are transition from IPv4 to IPv6, and from IPv6 to
2173  * 		IPv4. The helper takes care of the groundwork for the
2174  * 		transition, including resizing the socket buffer. The eBPF
2175  * 		program is expected to fill the new headers, if any, via
2176  * 		**skb_store_bytes**\ () and to recompute the checksums with
2177  * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
2178  * 		(). The main case for this helper is to perform NAT64
2179  * 		operations out of an eBPF program.
2180  *
2181  * 		Internally, the GSO type is marked as dodgy so that headers are
2182  * 		checked and segments are recalculated by the GSO/GRO engine.
2183  * 		The size for GSO target is adapted as well.
2184  *
2185  * 		All values for *flags* are reserved for future usage, and must
2186  * 		be left at zero.
2187  *
2188  * 		A call to this helper is susceptible to change the underlying
2189  * 		packet buffer. Therefore, at load time, all checks on pointers
2190  * 		previously done by the verifier are invalidated and must be
2191  * 		performed again, if the helper is used in combination with
2192  * 		direct packet access.
2193  * 	Return
2194  * 		0 on success, or a negative error in case of failure.
2195  *
2196  * long bpf_skb_change_type(struct sk_buff *skb, u32 type)
2197  * 	Description
2198  * 		Change the packet type for the packet associated to *skb*. This
2199  * 		comes down to setting *skb*\ **->pkt_type** to *type*, except
2200  * 		the eBPF program does not have a write access to *skb*\
2201  * 		**->pkt_type** beside this helper. Using a helper here allows
2202  * 		for graceful handling of errors.
2203  *
2204  * 		The major use case is to change incoming *skb*s to
2205  * 		**PACKET_HOST** in a programmatic way instead of having to
2206  * 		recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
2207  * 		example.
2208  *
2209  * 		Note that *type* only allows certain values. At this time, they
2210  * 		are:
2211  *
2212  * 		**PACKET_HOST**
2213  * 			Packet is for us.
2214  * 		**PACKET_BROADCAST**
2215  * 			Send packet to all.
2216  * 		**PACKET_MULTICAST**
2217  * 			Send packet to group.
2218  * 		**PACKET_OTHERHOST**
2219  * 			Send packet to someone else.
2220  * 	Return
2221  * 		0 on success, or a negative error in case of failure.
2222  *
2223  * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
2224  * 	Description
2225  * 		Check whether *skb* is a descendant of the cgroup2 held by
2226  * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2227  * 	Return
2228  * 		The return value depends on the result of the test, and can be:
2229  *
2230  * 		* 0, if the *skb* failed the cgroup2 descendant test.
2231  * 		* 1, if the *skb* succeeded the cgroup2 descendant test.
2232  * 		* A negative error code, if an error occurred.
2233  *
2234  * u32 bpf_get_hash_recalc(struct sk_buff *skb)
2235  * 	Description
2236  * 		Retrieve the hash of the packet, *skb*\ **->hash**. If it is
2237  * 		not set, in particular if the hash was cleared due to mangling,
2238  * 		recompute this hash. Later accesses to the hash can be done
2239  * 		directly with *skb*\ **->hash**.
2240  *
2241  * 		Calling **bpf_set_hash_invalid**\ (), changing a packet
2242  * 		prototype with **bpf_skb_change_proto**\ (), or calling
2243  * 		**bpf_skb_store_bytes**\ () with the
2244  * 		**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
2245  * 		the hash and to trigger a new computation for the next call to
2246  * 		**bpf_get_hash_recalc**\ ().
2247  * 	Return
2248  * 		The 32-bit hash.
2249  *
2250  * u64 bpf_get_current_task(void)
2251  * 	Return
2252  * 		A pointer to the current task struct.
2253  *
2254  * long bpf_probe_write_user(void *dst, const void *src, u32 len)
2255  * 	Description
2256  * 		Attempt in a safe way to write *len* bytes from the buffer
2257  * 		*src* to *dst* in memory. It only works for threads that are in
2258  * 		user context, and *dst* must be a valid user space address.
2259  *
2260  * 		This helper should not be used to implement any kind of
2261  * 		security mechanism because of TOC-TOU attacks, but rather to
2262  * 		debug, divert, and manipulate execution of semi-cooperative
2263  * 		processes.
2264  *
2265  * 		Keep in mind that this feature is meant for experiments, and it
2266  * 		has a risk of crashing the system and running programs.
2267  * 		Therefore, when an eBPF program using this helper is attached,
2268  * 		a warning including PID and process name is printed to kernel
2269  * 		logs.
2270  * 	Return
2271  * 		0 on success, or a negative error in case of failure.
2272  *
2273  * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
2274  * 	Description
2275  * 		Check whether the probe is being run is the context of a given
2276  * 		subset of the cgroup2 hierarchy. The cgroup2 to test is held by
2277  * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2278  * 	Return
2279  * 		The return value depends on the result of the test, and can be:
2280  *
2281  *		* 1, if current task belongs to the cgroup2.
2282  *		* 0, if current task does not belong to the cgroup2.
2283  * 		* A negative error code, if an error occurred.
2284  *
2285  * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
2286  * 	Description
2287  * 		Resize (trim or grow) the packet associated to *skb* to the
2288  * 		new *len*. The *flags* are reserved for future usage, and must
2289  * 		be left at zero.
2290  *
2291  * 		The basic idea is that the helper performs the needed work to
2292  * 		change the size of the packet, then the eBPF program rewrites
2293  * 		the rest via helpers like **bpf_skb_store_bytes**\ (),
2294  * 		**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
2295  * 		and others. This helper is a slow path utility intended for
2296  * 		replies with control messages. And because it is targeted for
2297  * 		slow path, the helper itself can afford to be slow: it
2298  * 		implicitly linearizes, unclones and drops offloads from the
2299  * 		*skb*.
2300  *
2301  * 		A call to this helper is susceptible to change the underlying
2302  * 		packet buffer. Therefore, at load time, all checks on pointers
2303  * 		previously done by the verifier are invalidated and must be
2304  * 		performed again, if the helper is used in combination with
2305  * 		direct packet access.
2306  * 	Return
2307  * 		0 on success, or a negative error in case of failure.
2308  *
2309  * long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
2310  * 	Description
2311  * 		Pull in non-linear data in case the *skb* is non-linear and not
2312  * 		all of *len* are part of the linear section. Make *len* bytes
2313  * 		from *skb* readable and writable. If a zero value is passed for
2314  * 		*len*, then the whole length of the *skb* is pulled.
2315  *
2316  * 		This helper is only needed for reading and writing with direct
2317  * 		packet access.
2318  *
2319  * 		For direct packet access, testing that offsets to access
2320  * 		are within packet boundaries (test on *skb*\ **->data_end**) is
2321  * 		susceptible to fail if offsets are invalid, or if the requested
2322  * 		data is in non-linear parts of the *skb*. On failure the
2323  * 		program can just bail out, or in the case of a non-linear
2324  * 		buffer, use a helper to make the data available. The
2325  * 		**bpf_skb_load_bytes**\ () helper is a first solution to access
2326  * 		the data. Another one consists in using **bpf_skb_pull_data**
2327  * 		to pull in once the non-linear parts, then retesting and
2328  * 		eventually access the data.
2329  *
2330  * 		At the same time, this also makes sure the *skb* is uncloned,
2331  * 		which is a necessary condition for direct write. As this needs
2332  * 		to be an invariant for the write part only, the verifier
2333  * 		detects writes and adds a prologue that is calling
2334  * 		**bpf_skb_pull_data()** to effectively unclone the *skb* from
2335  * 		the very beginning in case it is indeed cloned.
2336  *
2337  * 		A call to this helper is susceptible to change the underlying
2338  * 		packet buffer. Therefore, at load time, all checks on pointers
2339  * 		previously done by the verifier are invalidated and must be
2340  * 		performed again, if the helper is used in combination with
2341  * 		direct packet access.
2342  * 	Return
2343  * 		0 on success, or a negative error in case of failure.
2344  *
2345  * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
2346  * 	Description
2347  * 		Add the checksum *csum* into *skb*\ **->csum** in case the
2348  * 		driver has supplied a checksum for the entire packet into that
2349  * 		field. Return an error otherwise. This helper is intended to be
2350  * 		used in combination with **bpf_csum_diff**\ (), in particular
2351  * 		when the checksum needs to be updated after data has been
2352  * 		written into the packet through direct packet access.
2353  * 	Return
2354  * 		The checksum on success, or a negative error code in case of
2355  * 		failure.
2356  *
2357  * void bpf_set_hash_invalid(struct sk_buff *skb)
2358  * 	Description
2359  * 		Invalidate the current *skb*\ **->hash**. It can be used after
2360  * 		mangling on headers through direct packet access, in order to
2361  * 		indicate that the hash is outdated and to trigger a
2362  * 		recalculation the next time the kernel tries to access this
2363  * 		hash or when the **bpf_get_hash_recalc**\ () helper is called.
2364  *
2365  * long bpf_get_numa_node_id(void)
2366  * 	Description
2367  * 		Return the id of the current NUMA node. The primary use case
2368  * 		for this helper is the selection of sockets for the local NUMA
2369  * 		node, when the program is attached to sockets using the
2370  * 		**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
2371  * 		but the helper is also available to other eBPF program types,
2372  * 		similarly to **bpf_get_smp_processor_id**\ ().
2373  * 	Return
2374  * 		The id of current NUMA node.
2375  *
2376  * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
2377  * 	Description
2378  * 		Grows headroom of packet associated to *skb* and adjusts the
2379  * 		offset of the MAC header accordingly, adding *len* bytes of
2380  * 		space. It automatically extends and reallocates memory as
2381  * 		required.
2382  *
2383  * 		This helper can be used on a layer 3 *skb* to push a MAC header
2384  * 		for redirection into a layer 2 device.
2385  *
2386  * 		All values for *flags* are reserved for future usage, and must
2387  * 		be left at zero.
2388  *
2389  * 		A call to this helper is susceptible to change the underlying
2390  * 		packet buffer. Therefore, at load time, all checks on pointers
2391  * 		previously done by the verifier are invalidated and must be
2392  * 		performed again, if the helper is used in combination with
2393  * 		direct packet access.
2394  * 	Return
2395  * 		0 on success, or a negative error in case of failure.
2396  *
2397  * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
2398  * 	Description
2399  * 		Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
2400  * 		it is possible to use a negative value for *delta*. This helper
2401  * 		can be used to prepare the packet for pushing or popping
2402  * 		headers.
2403  *
2404  * 		A call to this helper is susceptible to change the underlying
2405  * 		packet buffer. Therefore, at load time, all checks on pointers
2406  * 		previously done by the verifier are invalidated and must be
2407  * 		performed again, if the helper is used in combination with
2408  * 		direct packet access.
2409  * 	Return
2410  * 		0 on success, or a negative error in case of failure.
2411  *
2412  * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
2413  * 	Description
2414  * 		Copy a NUL terminated string from an unsafe kernel address
2415  * 		*unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
2416  * 		more details.
2417  *
2418  * 		Generally, use **bpf_probe_read_user_str**\ () or
2419  * 		**bpf_probe_read_kernel_str**\ () instead.
2420  * 	Return
2421  * 		On success, the strictly positive length of the string,
2422  * 		including the trailing NUL character. On error, a negative
2423  * 		value.
2424  *
2425  * u64 bpf_get_socket_cookie(struct sk_buff *skb)
2426  * 	Description
2427  * 		If the **struct sk_buff** pointed by *skb* has a known socket,
2428  * 		retrieve the cookie (generated by the kernel) of this socket.
2429  * 		If no cookie has been set yet, generate a new cookie. Once
2430  * 		generated, the socket cookie remains stable for the life of the
2431  * 		socket. This helper can be useful for monitoring per socket
2432  * 		networking traffic statistics as it provides a global socket
2433  * 		identifier that can be assumed unique.
2434  * 	Return
2435  * 		A 8-byte long unique number on success, or 0 if the socket
2436  * 		field is missing inside *skb*.
2437  *
2438  * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
2439  * 	Description
2440  * 		Equivalent to bpf_get_socket_cookie() helper that accepts
2441  * 		*skb*, but gets socket from **struct bpf_sock_addr** context.
2442  * 	Return
2443  * 		A 8-byte long unique number.
2444  *
2445  * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
2446  * 	Description
2447  * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2448  * 		*skb*, but gets socket from **struct bpf_sock_ops** context.
2449  * 	Return
2450  * 		A 8-byte long unique number.
2451  *
2452  * u64 bpf_get_socket_cookie(struct sock *sk)
2453  * 	Description
2454  * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2455  * 		*sk*, but gets socket from a BTF **struct sock**. This helper
2456  * 		also works for sleepable programs.
2457  * 	Return
2458  * 		A 8-byte long unique number or 0 if *sk* is NULL.
2459  *
2460  * u32 bpf_get_socket_uid(struct sk_buff *skb)
2461  * 	Return
2462  * 		The owner UID of the socket associated to *skb*. If the socket
2463  * 		is **NULL**, or if it is not a full socket (i.e. if it is a
2464  * 		time-wait or a request socket instead), **overflowuid** value
2465  * 		is returned (note that **overflowuid** might also be the actual
2466  * 		UID value for the socket).
2467  *
2468  * long bpf_set_hash(struct sk_buff *skb, u32 hash)
2469  * 	Description
2470  * 		Set the full hash for *skb* (set the field *skb*\ **->hash**)
2471  * 		to value *hash*.
2472  * 	Return
2473  * 		0
2474  *
2475  * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2476  * 	Description
2477  * 		Emulate a call to **setsockopt()** on the socket associated to
2478  * 		*bpf_socket*, which must be a full socket. The *level* at
2479  * 		which the option resides and the name *optname* of the option
2480  * 		must be specified, see **setsockopt(2)** for more information.
2481  * 		The option value of length *optlen* is pointed by *optval*.
2482  *
2483  * 		*bpf_socket* should be one of the following:
2484  *
2485  * 		* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2486  * 		* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2487  * 		  and **BPF_CGROUP_INET6_CONNECT**.
2488  *
2489  * 		This helper actually implements a subset of **setsockopt()**.
2490  * 		It supports the following *level*\ s:
2491  *
2492  * 		* **SOL_SOCKET**, which supports the following *optname*\ s:
2493  * 		  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
2494  * 		  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
2495  * 		  **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
2496  * 		* **IPPROTO_TCP**, which supports the following *optname*\ s:
2497  * 		  **TCP_CONGESTION**, **TCP_BPF_IW**,
2498  * 		  **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
2499  * 		  **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
2500  *		  **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
2501  * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2502  * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2503  * 	Return
2504  * 		0 on success, or a negative error in case of failure.
2505  *
2506  * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
2507  * 	Description
2508  * 		Grow or shrink the room for data in the packet associated to
2509  * 		*skb* by *len_diff*, and according to the selected *mode*.
2510  *
2511  * 		By default, the helper will reset any offloaded checksum
2512  * 		indicator of the skb to CHECKSUM_NONE. This can be avoided
2513  * 		by the following flag:
2514  *
2515  * 		* **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
2516  * 		  checksum data of the skb to CHECKSUM_NONE.
2517  *
2518  *		There are two supported modes at this time:
2519  *
2520  *		* **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
2521  *		  (room space is added or removed below the layer 2 header).
2522  *
2523  * 		* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
2524  * 		  (room space is added or removed below the layer 3 header).
2525  *
2526  *		The following flags are supported at this time:
2527  *
2528  *		* **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
2529  *		  Adjusting mss in this way is not allowed for datagrams.
2530  *
2531  *		* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
2532  *		  **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
2533  *		  Any new space is reserved to hold a tunnel header.
2534  *		  Configure skb offsets and other fields accordingly.
2535  *
2536  *		* **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
2537  *		  **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
2538  *		  Use with ENCAP_L3 flags to further specify the tunnel type.
2539  *
2540  *		* **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
2541  *		  Use with ENCAP_L3/L4 flags to further specify the tunnel
2542  *		  type; *len* is the length of the inner MAC header.
2543  *
2544  *		* **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
2545  *		  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
2546  *		  L2 type as Ethernet.
2547  *
2548  * 		A call to this helper is susceptible to change the underlying
2549  * 		packet buffer. Therefore, at load time, all checks on pointers
2550  * 		previously done by the verifier are invalidated and must be
2551  * 		performed again, if the helper is used in combination with
2552  * 		direct packet access.
2553  * 	Return
2554  * 		0 on success, or a negative error in case of failure.
2555  *
2556  * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
2557  * 	Description
2558  * 		Redirect the packet to the endpoint referenced by *map* at
2559  * 		index *key*. Depending on its type, this *map* can contain
2560  * 		references to net devices (for forwarding packets through other
2561  * 		ports), or to CPUs (for redirecting XDP frames to another CPU;
2562  * 		but this is only implemented for native XDP (with driver
2563  * 		support) as of this writing).
2564  *
2565  * 		The lower two bits of *flags* are used as the return code if
2566  * 		the map lookup fails. This is so that the return value can be
2567  * 		one of the XDP program return codes up to **XDP_TX**, as chosen
2568  * 		by the caller. The higher bits of *flags* can be set to
2569  * 		BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
2570  *
2571  * 		With BPF_F_BROADCAST the packet will be broadcasted to all the
2572  * 		interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
2573  * 		interface will be excluded when do broadcasting.
2574  *
2575  * 		See also **bpf_redirect**\ (), which only supports redirecting
2576  * 		to an ifindex, but doesn't require a map to do so.
2577  * 	Return
2578  * 		**XDP_REDIRECT** on success, or the value of the two lower bits
2579  * 		of the *flags* argument on error.
2580  *
2581  * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
2582  * 	Description
2583  * 		Redirect the packet to the socket referenced by *map* (of type
2584  * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2585  * 		egress interfaces can be used for redirection. The
2586  * 		**BPF_F_INGRESS** value in *flags* is used to make the
2587  * 		distinction (ingress path is selected if the flag is present,
2588  * 		egress path otherwise). This is the only flag supported for now.
2589  * 	Return
2590  * 		**SK_PASS** on success, or **SK_DROP** on error.
2591  *
2592  * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
2593  * 	Description
2594  * 		Add an entry to, or update a *map* referencing sockets. The
2595  * 		*skops* is used as a new value for the entry associated to
2596  * 		*key*. *flags* is one of:
2597  *
2598  * 		**BPF_NOEXIST**
2599  * 			The entry for *key* must not exist in the map.
2600  * 		**BPF_EXIST**
2601  * 			The entry for *key* must already exist in the map.
2602  * 		**BPF_ANY**
2603  * 			No condition on the existence of the entry for *key*.
2604  *
2605  * 		If the *map* has eBPF programs (parser and verdict), those will
2606  * 		be inherited by the socket being added. If the socket is
2607  * 		already attached to eBPF programs, this results in an error.
2608  * 	Return
2609  * 		0 on success, or a negative error in case of failure.
2610  *
2611  * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
2612  * 	Description
2613  * 		Adjust the address pointed by *xdp_md*\ **->data_meta** by
2614  * 		*delta* (which can be positive or negative). Note that this
2615  * 		operation modifies the address stored in *xdp_md*\ **->data**,
2616  * 		so the latter must be loaded only after the helper has been
2617  * 		called.
2618  *
2619  * 		The use of *xdp_md*\ **->data_meta** is optional and programs
2620  * 		are not required to use it. The rationale is that when the
2621  * 		packet is processed with XDP (e.g. as DoS filter), it is
2622  * 		possible to push further meta data along with it before passing
2623  * 		to the stack, and to give the guarantee that an ingress eBPF
2624  * 		program attached as a TC classifier on the same device can pick
2625  * 		this up for further post-processing. Since TC works with socket
2626  * 		buffers, it remains possible to set from XDP the **mark** or
2627  * 		**priority** pointers, or other pointers for the socket buffer.
2628  * 		Having this scratch space generic and programmable allows for
2629  * 		more flexibility as the user is free to store whatever meta
2630  * 		data they need.
2631  *
2632  * 		A call to this helper is susceptible to change the underlying
2633  * 		packet buffer. Therefore, at load time, all checks on pointers
2634  * 		previously done by the verifier are invalidated and must be
2635  * 		performed again, if the helper is used in combination with
2636  * 		direct packet access.
2637  * 	Return
2638  * 		0 on success, or a negative error in case of failure.
2639  *
2640  * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
2641  * 	Description
2642  * 		Read the value of a perf event counter, and store it into *buf*
2643  * 		of size *buf_size*. This helper relies on a *map* of type
2644  * 		**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
2645  * 		counter is selected when *map* is updated with perf event file
2646  * 		descriptors. The *map* is an array whose size is the number of
2647  * 		available CPUs, and each cell contains a value relative to one
2648  * 		CPU. The value to retrieve is indicated by *flags*, that
2649  * 		contains the index of the CPU to look up, masked with
2650  * 		**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
2651  * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
2652  * 		current CPU should be retrieved.
2653  *
2654  * 		This helper behaves in a way close to
2655  * 		**bpf_perf_event_read**\ () helper, save that instead of
2656  * 		just returning the value observed, it fills the *buf*
2657  * 		structure. This allows for additional data to be retrieved: in
2658  * 		particular, the enabled and running times (in *buf*\
2659  * 		**->enabled** and *buf*\ **->running**, respectively) are
2660  * 		copied. In general, **bpf_perf_event_read_value**\ () is
2661  * 		recommended over **bpf_perf_event_read**\ (), which has some
2662  * 		ABI issues and provides fewer functionalities.
2663  *
2664  * 		These values are interesting, because hardware PMU (Performance
2665  * 		Monitoring Unit) counters are limited resources. When there are
2666  * 		more PMU based perf events opened than available counters,
2667  * 		kernel will multiplex these events so each event gets certain
2668  * 		percentage (but not all) of the PMU time. In case that
2669  * 		multiplexing happens, the number of samples or counter value
2670  * 		will not reflect the case compared to when no multiplexing
2671  * 		occurs. This makes comparison between different runs difficult.
2672  * 		Typically, the counter value should be normalized before
2673  * 		comparing to other experiments. The usual normalization is done
2674  * 		as follows.
2675  *
2676  * 		::
2677  *
2678  * 			normalized_counter = counter * t_enabled / t_running
2679  *
2680  * 		Where t_enabled is the time enabled for event and t_running is
2681  * 		the time running for event since last normalization. The
2682  * 		enabled and running times are accumulated since the perf event
2683  * 		open. To achieve scaling factor between two invocations of an
2684  * 		eBPF program, users can use CPU id as the key (which is
2685  * 		typical for perf array usage model) to remember the previous
2686  * 		value and do the calculation inside the eBPF program.
2687  * 	Return
2688  * 		0 on success, or a negative error in case of failure.
2689  *
2690  * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
2691  * 	Description
2692  * 		For en eBPF program attached to a perf event, retrieve the
2693  * 		value of the event counter associated to *ctx* and store it in
2694  * 		the structure pointed by *buf* and of size *buf_size*. Enabled
2695  * 		and running times are also stored in the structure (see
2696  * 		description of helper **bpf_perf_event_read_value**\ () for
2697  * 		more details).
2698  * 	Return
2699  * 		0 on success, or a negative error in case of failure.
2700  *
2701  * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2702  * 	Description
2703  * 		Emulate a call to **getsockopt()** on the socket associated to
2704  * 		*bpf_socket*, which must be a full socket. The *level* at
2705  * 		which the option resides and the name *optname* of the option
2706  * 		must be specified, see **getsockopt(2)** for more information.
2707  * 		The retrieved value is stored in the structure pointed by
2708  * 		*opval* and of length *optlen*.
2709  *
2710  * 		*bpf_socket* should be one of the following:
2711  *
2712  * 		* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2713  * 		* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2714  * 		  and **BPF_CGROUP_INET6_CONNECT**.
2715  *
2716  * 		This helper actually implements a subset of **getsockopt()**.
2717  * 		It supports the following *level*\ s:
2718  *
2719  * 		* **IPPROTO_TCP**, which supports *optname*
2720  * 		  **TCP_CONGESTION**.
2721  * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2722  * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2723  * 	Return
2724  * 		0 on success, or a negative error in case of failure.
2725  *
2726  * long bpf_override_return(struct pt_regs *regs, u64 rc)
2727  * 	Description
2728  * 		Used for error injection, this helper uses kprobes to override
2729  * 		the return value of the probed function, and to set it to *rc*.
2730  * 		The first argument is the context *regs* on which the kprobe
2731  * 		works.
2732  *
2733  * 		This helper works by setting the PC (program counter)
2734  * 		to an override function which is run in place of the original
2735  * 		probed function. This means the probed function is not run at
2736  * 		all. The replacement function just returns with the required
2737  * 		value.
2738  *
2739  * 		This helper has security implications, and thus is subject to
2740  * 		restrictions. It is only available if the kernel was compiled
2741  * 		with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
2742  * 		option, and in this case it only works on functions tagged with
2743  * 		**ALLOW_ERROR_INJECTION** in the kernel code.
2744  *
2745  * 		Also, the helper is only available for the architectures having
2746  * 		the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
2747  * 		x86 architecture is the only one to support this feature.
2748  * 	Return
2749  * 		0
2750  *
2751  * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
2752  * 	Description
2753  * 		Attempt to set the value of the **bpf_sock_ops_cb_flags** field
2754  * 		for the full TCP socket associated to *bpf_sock_ops* to
2755  * 		*argval*.
2756  *
2757  * 		The primary use of this field is to determine if there should
2758  * 		be calls to eBPF programs of type
2759  * 		**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
2760  * 		code. A program of the same type can change its value, per
2761  * 		connection and as necessary, when the connection is
2762  * 		established. This field is directly accessible for reading, but
2763  * 		this helper must be used for updates in order to return an
2764  * 		error if an eBPF program tries to set a callback that is not
2765  * 		supported in the current kernel.
2766  *
2767  * 		*argval* is a flag array which can combine these flags:
2768  *
2769  * 		* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
2770  * 		* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
2771  * 		* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
2772  * 		* **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
2773  *
2774  * 		Therefore, this function can be used to clear a callback flag by
2775  * 		setting the appropriate bit to zero. e.g. to disable the RTO
2776  * 		callback:
2777  *
2778  * 		**bpf_sock_ops_cb_flags_set(bpf_sock,**
2779  * 			**bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
2780  *
2781  * 		Here are some examples of where one could call such eBPF
2782  * 		program:
2783  *
2784  * 		* When RTO fires.
2785  * 		* When a packet is retransmitted.
2786  * 		* When the connection terminates.
2787  * 		* When a packet is sent.
2788  * 		* When a packet is received.
2789  * 	Return
2790  * 		Code **-EINVAL** if the socket is not a full TCP socket;
2791  * 		otherwise, a positive number containing the bits that could not
2792  * 		be set is returned (which comes down to 0 if all bits were set
2793  * 		as required).
2794  *
2795  * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
2796  * 	Description
2797  * 		This helper is used in programs implementing policies at the
2798  * 		socket level. If the message *msg* is allowed to pass (i.e. if
2799  * 		the verdict eBPF program returns **SK_PASS**), redirect it to
2800  * 		the socket referenced by *map* (of type
2801  * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2802  * 		egress interfaces can be used for redirection. The
2803  * 		**BPF_F_INGRESS** value in *flags* is used to make the
2804  * 		distinction (ingress path is selected if the flag is present,
2805  * 		egress path otherwise). This is the only flag supported for now.
2806  * 	Return
2807  * 		**SK_PASS** on success, or **SK_DROP** on error.
2808  *
2809  * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
2810  * 	Description
2811  * 		For socket policies, apply the verdict of the eBPF program to
2812  * 		the next *bytes* (number of bytes) of message *msg*.
2813  *
2814  * 		For example, this helper can be used in the following cases:
2815  *
2816  * 		* A single **sendmsg**\ () or **sendfile**\ () system call
2817  * 		  contains multiple logical messages that the eBPF program is
2818  * 		  supposed to read and for which it should apply a verdict.
2819  * 		* An eBPF program only cares to read the first *bytes* of a
2820  * 		  *msg*. If the message has a large payload, then setting up
2821  * 		  and calling the eBPF program repeatedly for all bytes, even
2822  * 		  though the verdict is already known, would create unnecessary
2823  * 		  overhead.
2824  *
2825  * 		When called from within an eBPF program, the helper sets a
2826  * 		counter internal to the BPF infrastructure, that is used to
2827  * 		apply the last verdict to the next *bytes*. If *bytes* is
2828  * 		smaller than the current data being processed from a
2829  * 		**sendmsg**\ () or **sendfile**\ () system call, the first
2830  * 		*bytes* will be sent and the eBPF program will be re-run with
2831  * 		the pointer for start of data pointing to byte number *bytes*
2832  * 		**+ 1**. If *bytes* is larger than the current data being
2833  * 		processed, then the eBPF verdict will be applied to multiple
2834  * 		**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
2835  * 		consumed.
2836  *
2837  * 		Note that if a socket closes with the internal counter holding
2838  * 		a non-zero value, this is not a problem because data is not
2839  * 		being buffered for *bytes* and is sent as it is received.
2840  * 	Return
2841  * 		0
2842  *
2843  * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
2844  * 	Description
2845  * 		For socket policies, prevent the execution of the verdict eBPF
2846  * 		program for message *msg* until *bytes* (byte number) have been
2847  * 		accumulated.
2848  *
2849  * 		This can be used when one needs a specific number of bytes
2850  * 		before a verdict can be assigned, even if the data spans
2851  * 		multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
2852  * 		case would be a user calling **sendmsg**\ () repeatedly with
2853  * 		1-byte long message segments. Obviously, this is bad for
2854  * 		performance, but it is still valid. If the eBPF program needs
2855  * 		*bytes* bytes to validate a header, this helper can be used to
2856  * 		prevent the eBPF program to be called again until *bytes* have
2857  * 		been accumulated.
2858  * 	Return
2859  * 		0
2860  *
2861  * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
2862  * 	Description
2863  * 		For socket policies, pull in non-linear data from user space
2864  * 		for *msg* and set pointers *msg*\ **->data** and *msg*\
2865  * 		**->data_end** to *start* and *end* bytes offsets into *msg*,
2866  * 		respectively.
2867  *
2868  * 		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2869  * 		*msg* it can only parse data that the (**data**, **data_end**)
2870  * 		pointers have already consumed. For **sendmsg**\ () hooks this
2871  * 		is likely the first scatterlist element. But for calls relying
2872  * 		on the **sendpage** handler (e.g. **sendfile**\ ()) this will
2873  * 		be the range (**0**, **0**) because the data is shared with
2874  * 		user space and by default the objective is to avoid allowing
2875  * 		user space to modify data while (or after) eBPF verdict is
2876  * 		being decided. This helper can be used to pull in data and to
2877  * 		set the start and end pointer to given values. Data will be
2878  * 		copied if necessary (i.e. if data was not linear and if start
2879  * 		and end pointers do not point to the same chunk).
2880  *
2881  * 		A call to this helper is susceptible to change the underlying
2882  * 		packet buffer. Therefore, at load time, all checks on pointers
2883  * 		previously done by the verifier are invalidated and must be
2884  * 		performed again, if the helper is used in combination with
2885  * 		direct packet access.
2886  *
2887  * 		All values for *flags* are reserved for future usage, and must
2888  * 		be left at zero.
2889  * 	Return
2890  * 		0 on success, or a negative error in case of failure.
2891  *
2892  * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
2893  * 	Description
2894  * 		Bind the socket associated to *ctx* to the address pointed by
2895  * 		*addr*, of length *addr_len*. This allows for making outgoing
2896  * 		connection from the desired IP address, which can be useful for
2897  * 		example when all processes inside a cgroup should use one
2898  * 		single IP address on a host that has multiple IP configured.
2899  *
2900  * 		This helper works for IPv4 and IPv6, TCP and UDP sockets. The
2901  * 		domain (*addr*\ **->sa_family**) must be **AF_INET** (or
2902  * 		**AF_INET6**). It's advised to pass zero port (**sin_port**
2903  * 		or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
2904  * 		behavior and lets the kernel efficiently pick up an unused
2905  * 		port as long as 4-tuple is unique. Passing non-zero port might
2906  * 		lead to degraded performance.
2907  * 	Return
2908  * 		0 on success, or a negative error in case of failure.
2909  *
2910  * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
2911  * 	Description
2912  * 		Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
2913  * 		possible to both shrink and grow the packet tail.
2914  * 		Shrink done via *delta* being a negative integer.
2915  *
2916  * 		A call to this helper is susceptible to change the underlying
2917  * 		packet buffer. Therefore, at load time, all checks on pointers
2918  * 		previously done by the verifier are invalidated and must be
2919  * 		performed again, if the helper is used in combination with
2920  * 		direct packet access.
2921  * 	Return
2922  * 		0 on success, or a negative error in case of failure.
2923  *
2924  * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
2925  * 	Description
2926  * 		Retrieve the XFRM state (IP transform framework, see also
2927  * 		**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
2928  *
2929  * 		The retrieved value is stored in the **struct bpf_xfrm_state**
2930  * 		pointed by *xfrm_state* and of length *size*.
2931  *
2932  * 		All values for *flags* are reserved for future usage, and must
2933  * 		be left at zero.
2934  *
2935  * 		This helper is available only if the kernel was compiled with
2936  * 		**CONFIG_XFRM** configuration option.
2937  * 	Return
2938  * 		0 on success, or a negative error in case of failure.
2939  *
2940  * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
2941  * 	Description
2942  * 		Return a user or a kernel stack in bpf program provided buffer.
2943  * 		To achieve this, the helper needs *ctx*, which is a pointer
2944  * 		to the context on which the tracing program is executed.
2945  * 		To store the stacktrace, the bpf program provides *buf* with
2946  * 		a nonnegative *size*.
2947  *
2948  * 		The last argument, *flags*, holds the number of stack frames to
2949  * 		skip (from 0 to 255), masked with
2950  * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2951  * 		the following flags:
2952  *
2953  * 		**BPF_F_USER_STACK**
2954  * 			Collect a user space stack instead of a kernel stack.
2955  * 		**BPF_F_USER_BUILD_ID**
2956  * 			Collect buildid+offset instead of ips for user stack,
2957  * 			only valid if **BPF_F_USER_STACK** is also specified.
2958  *
2959  * 		**bpf_get_stack**\ () can collect up to
2960  * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
2961  * 		to sufficient large buffer size. Note that
2962  * 		this limit can be controlled with the **sysctl** program, and
2963  * 		that it should be manually increased in order to profile long
2964  * 		user stacks (such as stacks for Java programs). To do so, use:
2965  *
2966  * 		::
2967  *
2968  * 			# sysctl kernel.perf_event_max_stack=<new value>
2969  * 	Return
2970  * 		A non-negative value equal to or less than *size* on success,
2971  * 		or a negative error in case of failure.
2972  *
2973  * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
2974  * 	Description
2975  * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
2976  * 		it provides an easy way to load *len* bytes from *offset*
2977  * 		from the packet associated to *skb*, into the buffer pointed
2978  * 		by *to*. The difference to **bpf_skb_load_bytes**\ () is that
2979  * 		a fifth argument *start_header* exists in order to select a
2980  * 		base offset to start from. *start_header* can be one of:
2981  *
2982  * 		**BPF_HDR_START_MAC**
2983  * 			Base offset to load data from is *skb*'s mac header.
2984  * 		**BPF_HDR_START_NET**
2985  * 			Base offset to load data from is *skb*'s network header.
2986  *
2987  * 		In general, "direct packet access" is the preferred method to
2988  * 		access packet data, however, this helper is in particular useful
2989  * 		in socket filters where *skb*\ **->data** does not always point
2990  * 		to the start of the mac header and where "direct packet access"
2991  * 		is not available.
2992  * 	Return
2993  * 		0 on success, or a negative error in case of failure.
2994  *
2995  * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
2996  *	Description
2997  *		Do FIB lookup in kernel tables using parameters in *params*.
2998  *		If lookup is successful and result shows packet is to be
2999  *		forwarded, the neighbor tables are searched for the nexthop.
3000  *		If successful (ie., FIB lookup shows forwarding and nexthop
3001  *		is resolved), the nexthop address is returned in ipv4_dst
3002  *		or ipv6_dst based on family, smac is set to mac address of
3003  *		egress device, dmac is set to nexthop mac address, rt_metric
3004  *		is set to metric from route (IPv4/IPv6 only), and ifindex
3005  *		is set to the device index of the nexthop from the FIB lookup.
3006  *
3007  *		*plen* argument is the size of the passed in struct.
3008  *		*flags* argument can be a combination of one or more of the
3009  *		following values:
3010  *
3011  *		**BPF_FIB_LOOKUP_DIRECT**
3012  *			Do a direct table lookup vs full lookup using FIB
3013  *			rules.
3014  *		**BPF_FIB_LOOKUP_OUTPUT**
3015  *			Perform lookup from an egress perspective (default is
3016  *			ingress).
3017  *
3018  *		*ctx* is either **struct xdp_md** for XDP programs or
3019  *		**struct sk_buff** tc cls_act programs.
3020  *	Return
3021  *		* < 0 if any input argument is invalid
3022  *		*   0 on success (packet is forwarded, nexthop neighbor exists)
3023  *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
3024  *		  packet is not forwarded or needs assist from full stack
3025  *
3026  *		If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
3027  *		was exceeded and output params->mtu_result contains the MTU.
3028  *
3029  * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
3030  *	Description
3031  *		Add an entry to, or update a sockhash *map* referencing sockets.
3032  *		The *skops* is used as a new value for the entry associated to
3033  *		*key*. *flags* is one of:
3034  *
3035  *		**BPF_NOEXIST**
3036  *			The entry for *key* must not exist in the map.
3037  *		**BPF_EXIST**
3038  *			The entry for *key* must already exist in the map.
3039  *		**BPF_ANY**
3040  *			No condition on the existence of the entry for *key*.
3041  *
3042  *		If the *map* has eBPF programs (parser and verdict), those will
3043  *		be inherited by the socket being added. If the socket is
3044  *		already attached to eBPF programs, this results in an error.
3045  *	Return
3046  *		0 on success, or a negative error in case of failure.
3047  *
3048  * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
3049  *	Description
3050  *		This helper is used in programs implementing policies at the
3051  *		socket level. If the message *msg* is allowed to pass (i.e. if
3052  *		the verdict eBPF program returns **SK_PASS**), redirect it to
3053  *		the socket referenced by *map* (of type
3054  *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3055  *		egress interfaces can be used for redirection. The
3056  *		**BPF_F_INGRESS** value in *flags* is used to make the
3057  *		distinction (ingress path is selected if the flag is present,
3058  *		egress path otherwise). This is the only flag supported for now.
3059  *	Return
3060  *		**SK_PASS** on success, or **SK_DROP** on error.
3061  *
3062  * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
3063  *	Description
3064  *		This helper is used in programs implementing policies at the
3065  *		skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
3066  *		if the verdict eBPF program returns **SK_PASS**), redirect it
3067  *		to the socket referenced by *map* (of type
3068  *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3069  *		egress interfaces can be used for redirection. The
3070  *		**BPF_F_INGRESS** value in *flags* is used to make the
3071  *		distinction (ingress path is selected if the flag is present,
3072  *		egress otherwise). This is the only flag supported for now.
3073  *	Return
3074  *		**SK_PASS** on success, or **SK_DROP** on error.
3075  *
3076  * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
3077  *	Description
3078  *		Encapsulate the packet associated to *skb* within a Layer 3
3079  *		protocol header. This header is provided in the buffer at
3080  *		address *hdr*, with *len* its size in bytes. *type* indicates
3081  *		the protocol of the header and can be one of:
3082  *
3083  *		**BPF_LWT_ENCAP_SEG6**
3084  *			IPv6 encapsulation with Segment Routing Header
3085  *			(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
3086  *			the IPv6 header is computed by the kernel.
3087  *		**BPF_LWT_ENCAP_SEG6_INLINE**
3088  *			Only works if *skb* contains an IPv6 packet. Insert a
3089  *			Segment Routing Header (**struct ipv6_sr_hdr**) inside
3090  *			the IPv6 header.
3091  *		**BPF_LWT_ENCAP_IP**
3092  *			IP encapsulation (GRE/GUE/IPIP/etc). The outer header
3093  *			must be IPv4 or IPv6, followed by zero or more
3094  *			additional headers, up to **LWT_BPF_MAX_HEADROOM**
3095  *			total bytes in all prepended headers. Please note that
3096  *			if **skb_is_gso**\ (*skb*) is true, no more than two
3097  *			headers can be prepended, and the inner header, if
3098  *			present, should be either GRE or UDP/GUE.
3099  *
3100  *		**BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
3101  *		of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
3102  *		be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
3103  *		**BPF_PROG_TYPE_LWT_XMIT**.
3104  *
3105  * 		A call to this helper is susceptible to change the underlying
3106  * 		packet buffer. Therefore, at load time, all checks on pointers
3107  * 		previously done by the verifier are invalidated and must be
3108  * 		performed again, if the helper is used in combination with
3109  * 		direct packet access.
3110  *	Return
3111  * 		0 on success, or a negative error in case of failure.
3112  *
3113  * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
3114  *	Description
3115  *		Store *len* bytes from address *from* into the packet
3116  *		associated to *skb*, at *offset*. Only the flags, tag and TLVs
3117  *		inside the outermost IPv6 Segment Routing Header can be
3118  *		modified through this helper.
3119  *
3120  * 		A call to this helper is susceptible to change the underlying
3121  * 		packet buffer. Therefore, at load time, all checks on pointers
3122  * 		previously done by the verifier are invalidated and must be
3123  * 		performed again, if the helper is used in combination with
3124  * 		direct packet access.
3125  *	Return
3126  * 		0 on success, or a negative error in case of failure.
3127  *
3128  * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
3129  *	Description
3130  *		Adjust the size allocated to TLVs in the outermost IPv6
3131  *		Segment Routing Header contained in the packet associated to
3132  *		*skb*, at position *offset* by *delta* bytes. Only offsets
3133  *		after the segments are accepted. *delta* can be as well
3134  *		positive (growing) as negative (shrinking).
3135  *
3136  * 		A call to this helper is susceptible to change the underlying
3137  * 		packet buffer. Therefore, at load time, all checks on pointers
3138  * 		previously done by the verifier are invalidated and must be
3139  * 		performed again, if the helper is used in combination with
3140  * 		direct packet access.
3141  *	Return
3142  * 		0 on success, or a negative error in case of failure.
3143  *
3144  * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
3145  *	Description
3146  *		Apply an IPv6 Segment Routing action of type *action* to the
3147  *		packet associated to *skb*. Each action takes a parameter
3148  *		contained at address *param*, and of length *param_len* bytes.
3149  *		*action* can be one of:
3150  *
3151  *		**SEG6_LOCAL_ACTION_END_X**
3152  *			End.X action: Endpoint with Layer-3 cross-connect.
3153  *			Type of *param*: **struct in6_addr**.
3154  *		**SEG6_LOCAL_ACTION_END_T**
3155  *			End.T action: Endpoint with specific IPv6 table lookup.
3156  *			Type of *param*: **int**.
3157  *		**SEG6_LOCAL_ACTION_END_B6**
3158  *			End.B6 action: Endpoint bound to an SRv6 policy.
3159  *			Type of *param*: **struct ipv6_sr_hdr**.
3160  *		**SEG6_LOCAL_ACTION_END_B6_ENCAP**
3161  *			End.B6.Encap action: Endpoint bound to an SRv6
3162  *			encapsulation policy.
3163  *			Type of *param*: **struct ipv6_sr_hdr**.
3164  *
3165  * 		A call to this helper is susceptible to change the underlying
3166  * 		packet buffer. Therefore, at load time, all checks on pointers
3167  * 		previously done by the verifier are invalidated and must be
3168  * 		performed again, if the helper is used in combination with
3169  * 		direct packet access.
3170  *	Return
3171  * 		0 on success, or a negative error in case of failure.
3172  *
3173  * long bpf_rc_repeat(void *ctx)
3174  *	Description
3175  *		This helper is used in programs implementing IR decoding, to
3176  *		report a successfully decoded repeat key message. This delays
3177  *		the generation of a key up event for previously generated
3178  *		key down event.
3179  *
3180  *		Some IR protocols like NEC have a special IR message for
3181  *		repeating last button, for when a button is held down.
3182  *
3183  *		The *ctx* should point to the lirc sample as passed into
3184  *		the program.
3185  *
3186  *		This helper is only available is the kernel was compiled with
3187  *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3188  *		"**y**".
3189  *	Return
3190  *		0
3191  *
3192  * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
3193  *	Description
3194  *		This helper is used in programs implementing IR decoding, to
3195  *		report a successfully decoded key press with *scancode*,
3196  *		*toggle* value in the given *protocol*. The scancode will be
3197  *		translated to a keycode using the rc keymap, and reported as
3198  *		an input key down event. After a period a key up event is
3199  *		generated. This period can be extended by calling either
3200  *		**bpf_rc_keydown**\ () again with the same values, or calling
3201  *		**bpf_rc_repeat**\ ().
3202  *
3203  *		Some protocols include a toggle bit, in case the button was
3204  *		released and pressed again between consecutive scancodes.
3205  *
3206  *		The *ctx* should point to the lirc sample as passed into
3207  *		the program.
3208  *
3209  *		The *protocol* is the decoded protocol number (see
3210  *		**enum rc_proto** for some predefined values).
3211  *
3212  *		This helper is only available is the kernel was compiled with
3213  *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3214  *		"**y**".
3215  *	Return
3216  *		0
3217  *
3218  * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
3219  * 	Description
3220  * 		Return the cgroup v2 id of the socket associated with the *skb*.
3221  * 		This is roughly similar to the **bpf_get_cgroup_classid**\ ()
3222  * 		helper for cgroup v1 by providing a tag resp. identifier that
3223  * 		can be matched on or used for map lookups e.g. to implement
3224  * 		policy. The cgroup v2 id of a given path in the hierarchy is
3225  * 		exposed in user space through the f_handle API in order to get
3226  * 		to the same 64-bit id.
3227  *
3228  * 		This helper can be used on TC egress path, but not on ingress,
3229  * 		and is available only if the kernel was compiled with the
3230  * 		**CONFIG_SOCK_CGROUP_DATA** configuration option.
3231  * 	Return
3232  * 		The id is returned or 0 in case the id could not be retrieved.
3233  *
3234  * u64 bpf_get_current_cgroup_id(void)
3235  * 	Return
3236  * 		A 64-bit integer containing the current cgroup id based
3237  * 		on the cgroup within which the current task is running.
3238  *
3239  * void *bpf_get_local_storage(void *map, u64 flags)
3240  *	Description
3241  *		Get the pointer to the local storage area.
3242  *		The type and the size of the local storage is defined
3243  *		by the *map* argument.
3244  *		The *flags* meaning is specific for each map type,
3245  *		and has to be 0 for cgroup local storage.
3246  *
3247  *		Depending on the BPF program type, a local storage area
3248  *		can be shared between multiple instances of the BPF program,
3249  *		running simultaneously.
3250  *
3251  *		A user should care about the synchronization by himself.
3252  *		For example, by using the **BPF_ATOMIC** instructions to alter
3253  *		the shared data.
3254  *	Return
3255  *		A pointer to the local storage area.
3256  *
3257  * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
3258  *	Description
3259  *		Select a **SO_REUSEPORT** socket from a
3260  *		**BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
3261  *		It checks the selected socket is matching the incoming
3262  *		request in the socket buffer.
3263  *	Return
3264  *		0 on success, or a negative error in case of failure.
3265  *
3266  * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
3267  *	Description
3268  *		Return id of cgroup v2 that is ancestor of cgroup associated
3269  *		with the *skb* at the *ancestor_level*.  The root cgroup is at
3270  *		*ancestor_level* zero and each step down the hierarchy
3271  *		increments the level. If *ancestor_level* == level of cgroup
3272  *		associated with *skb*, then return value will be same as that
3273  *		of **bpf_skb_cgroup_id**\ ().
3274  *
3275  *		The helper is useful to implement policies based on cgroups
3276  *		that are upper in hierarchy than immediate cgroup associated
3277  *		with *skb*.
3278  *
3279  *		The format of returned id and helper limitations are same as in
3280  *		**bpf_skb_cgroup_id**\ ().
3281  *	Return
3282  *		The id is returned or 0 in case the id could not be retrieved.
3283  *
3284  * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3285  *	Description
3286  *		Look for TCP socket matching *tuple*, optionally in a child
3287  *		network namespace *netns*. The return value must be checked,
3288  *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3289  *
3290  *		The *ctx* should point to the context of the program, such as
3291  *		the skb or socket (depending on the hook in use). This is used
3292  *		to determine the base network namespace for the lookup.
3293  *
3294  *		*tuple_size* must be one of:
3295  *
3296  *		**sizeof**\ (*tuple*\ **->ipv4**)
3297  *			Look for an IPv4 socket.
3298  *		**sizeof**\ (*tuple*\ **->ipv6**)
3299  *			Look for an IPv6 socket.
3300  *
3301  *		If the *netns* is a negative signed 32-bit integer, then the
3302  *		socket lookup table in the netns associated with the *ctx*
3303  *		will be used. For the TC hooks, this is the netns of the device
3304  *		in the skb. For socket hooks, this is the netns of the socket.
3305  *		If *netns* is any other signed 32-bit value greater than or
3306  *		equal to zero then it specifies the ID of the netns relative to
3307  *		the netns associated with the *ctx*. *netns* values beyond the
3308  *		range of 32-bit integers are reserved for future use.
3309  *
3310  *		All values for *flags* are reserved for future usage, and must
3311  *		be left at zero.
3312  *
3313  *		This helper is available only if the kernel was compiled with
3314  *		**CONFIG_NET** configuration option.
3315  *	Return
3316  *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3317  *		For sockets with reuseport option, the **struct bpf_sock**
3318  *		result is from *reuse*\ **->socks**\ [] using the hash of the
3319  *		tuple.
3320  *
3321  * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3322  *	Description
3323  *		Look for UDP socket matching *tuple*, optionally in a child
3324  *		network namespace *netns*. The return value must be checked,
3325  *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3326  *
3327  *		The *ctx* should point to the context of the program, such as
3328  *		the skb or socket (depending on the hook in use). This is used
3329  *		to determine the base network namespace for the lookup.
3330  *
3331  *		*tuple_size* must be one of:
3332  *
3333  *		**sizeof**\ (*tuple*\ **->ipv4**)
3334  *			Look for an IPv4 socket.
3335  *		**sizeof**\ (*tuple*\ **->ipv6**)
3336  *			Look for an IPv6 socket.
3337  *
3338  *		If the *netns* is a negative signed 32-bit integer, then the
3339  *		socket lookup table in the netns associated with the *ctx*
3340  *		will be used. For the TC hooks, this is the netns of the device
3341  *		in the skb. For socket hooks, this is the netns of the socket.
3342  *		If *netns* is any other signed 32-bit value greater than or
3343  *		equal to zero then it specifies the ID of the netns relative to
3344  *		the netns associated with the *ctx*. *netns* values beyond the
3345  *		range of 32-bit integers are reserved for future use.
3346  *
3347  *		All values for *flags* are reserved for future usage, and must
3348  *		be left at zero.
3349  *
3350  *		This helper is available only if the kernel was compiled with
3351  *		**CONFIG_NET** configuration option.
3352  *	Return
3353  *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3354  *		For sockets with reuseport option, the **struct bpf_sock**
3355  *		result is from *reuse*\ **->socks**\ [] using the hash of the
3356  *		tuple.
3357  *
3358  * long bpf_sk_release(void *sock)
3359  *	Description
3360  *		Release the reference held by *sock*. *sock* must be a
3361  *		non-**NULL** pointer that was returned from
3362  *		**bpf_sk_lookup_xxx**\ ().
3363  *	Return
3364  *		0 on success, or a negative error in case of failure.
3365  *
3366  * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
3367  * 	Description
3368  * 		Push an element *value* in *map*. *flags* is one of:
3369  *
3370  * 		**BPF_EXIST**
3371  * 			If the queue/stack is full, the oldest element is
3372  * 			removed to make room for this.
3373  * 	Return
3374  * 		0 on success, or a negative error in case of failure.
3375  *
3376  * long bpf_map_pop_elem(struct bpf_map *map, void *value)
3377  * 	Description
3378  * 		Pop an element from *map*.
3379  * 	Return
3380  * 		0 on success, or a negative error in case of failure.
3381  *
3382  * long bpf_map_peek_elem(struct bpf_map *map, void *value)
3383  * 	Description
3384  * 		Get an element from *map* without removing it.
3385  * 	Return
3386  * 		0 on success, or a negative error in case of failure.
3387  *
3388  * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3389  *	Description
3390  *		For socket policies, insert *len* bytes into *msg* at offset
3391  *		*start*.
3392  *
3393  *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
3394  *		*msg* it may want to insert metadata or options into the *msg*.
3395  *		This can later be read and used by any of the lower layer BPF
3396  *		hooks.
3397  *
3398  *		This helper may fail if under memory pressure (a malloc
3399  *		fails) in these cases BPF programs will get an appropriate
3400  *		error and BPF programs will need to handle them.
3401  *	Return
3402  *		0 on success, or a negative error in case of failure.
3403  *
3404  * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3405  *	Description
3406  *		Will remove *len* bytes from a *msg* starting at byte *start*.
3407  *		This may result in **ENOMEM** errors under certain situations if
3408  *		an allocation and copy are required due to a full ring buffer.
3409  *		However, the helper will try to avoid doing the allocation
3410  *		if possible. Other errors can occur if input parameters are
3411  *		invalid either due to *start* byte not being valid part of *msg*
3412  *		payload and/or *pop* value being to large.
3413  *	Return
3414  *		0 on success, or a negative error in case of failure.
3415  *
3416  * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
3417  *	Description
3418  *		This helper is used in programs implementing IR decoding, to
3419  *		report a successfully decoded pointer movement.
3420  *
3421  *		The *ctx* should point to the lirc sample as passed into
3422  *		the program.
3423  *
3424  *		This helper is only available is the kernel was compiled with
3425  *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3426  *		"**y**".
3427  *	Return
3428  *		0
3429  *
3430  * long bpf_spin_lock(struct bpf_spin_lock *lock)
3431  *	Description
3432  *		Acquire a spinlock represented by the pointer *lock*, which is
3433  *		stored as part of a value of a map. Taking the lock allows to
3434  *		safely update the rest of the fields in that value. The
3435  *		spinlock can (and must) later be released with a call to
3436  *		**bpf_spin_unlock**\ (\ *lock*\ ).
3437  *
3438  *		Spinlocks in BPF programs come with a number of restrictions
3439  *		and constraints:
3440  *
3441  *		* **bpf_spin_lock** objects are only allowed inside maps of
3442  *		  types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
3443  *		  list could be extended in the future).
3444  *		* BTF description of the map is mandatory.
3445  *		* The BPF program can take ONE lock at a time, since taking two
3446  *		  or more could cause dead locks.
3447  *		* Only one **struct bpf_spin_lock** is allowed per map element.
3448  *		* When the lock is taken, calls (either BPF to BPF or helpers)
3449  *		  are not allowed.
3450  *		* The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
3451  *		  allowed inside a spinlock-ed region.
3452  *		* The BPF program MUST call **bpf_spin_unlock**\ () to release
3453  *		  the lock, on all execution paths, before it returns.
3454  *		* The BPF program can access **struct bpf_spin_lock** only via
3455  *		  the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
3456  *		  helpers. Loading or storing data into the **struct
3457  *		  bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
3458  *		* To use the **bpf_spin_lock**\ () helper, the BTF description
3459  *		  of the map value must be a struct and have **struct
3460  *		  bpf_spin_lock** *anyname*\ **;** field at the top level.
3461  *		  Nested lock inside another struct is not allowed.
3462  *		* The **struct bpf_spin_lock** *lock* field in a map value must
3463  *		  be aligned on a multiple of 4 bytes in that value.
3464  *		* Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
3465  *		  the **bpf_spin_lock** field to user space.
3466  *		* Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
3467  *		  a BPF program, do not update the **bpf_spin_lock** field.
3468  *		* **bpf_spin_lock** cannot be on the stack or inside a
3469  *		  networking packet (it can only be inside of a map values).
3470  *		* **bpf_spin_lock** is available to root only.
3471  *		* Tracing programs and socket filter programs cannot use
3472  *		  **bpf_spin_lock**\ () due to insufficient preemption checks
3473  *		  (but this may change in the future).
3474  *		* **bpf_spin_lock** is not allowed in inner maps of map-in-map.
3475  *	Return
3476  *		0
3477  *
3478  * long bpf_spin_unlock(struct bpf_spin_lock *lock)
3479  *	Description
3480  *		Release the *lock* previously locked by a call to
3481  *		**bpf_spin_lock**\ (\ *lock*\ ).
3482  *	Return
3483  *		0
3484  *
3485  * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
3486  *	Description
3487  *		This helper gets a **struct bpf_sock** pointer such
3488  *		that all the fields in this **bpf_sock** can be accessed.
3489  *	Return
3490  *		A **struct bpf_sock** pointer on success, or **NULL** in
3491  *		case of failure.
3492  *
3493  * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
3494  *	Description
3495  *		This helper gets a **struct bpf_tcp_sock** pointer from a
3496  *		**struct bpf_sock** pointer.
3497  *	Return
3498  *		A **struct bpf_tcp_sock** pointer on success, or **NULL** in
3499  *		case of failure.
3500  *
3501  * long bpf_skb_ecn_set_ce(struct sk_buff *skb)
3502  *	Description
3503  *		Set ECN (Explicit Congestion Notification) field of IP header
3504  *		to **CE** (Congestion Encountered) if current value is **ECT**
3505  *		(ECN Capable Transport). Otherwise, do nothing. Works with IPv6
3506  *		and IPv4.
3507  *	Return
3508  *		1 if the **CE** flag is set (either by the current helper call
3509  *		or because it was already present), 0 if it is not set.
3510  *
3511  * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
3512  *	Description
3513  *		Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
3514  *		**bpf_sk_release**\ () is unnecessary and not allowed.
3515  *	Return
3516  *		A **struct bpf_sock** pointer on success, or **NULL** in
3517  *		case of failure.
3518  *
3519  * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3520  *	Description
3521  *		Look for TCP socket matching *tuple*, optionally in a child
3522  *		network namespace *netns*. The return value must be checked,
3523  *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3524  *
3525  *		This function is identical to **bpf_sk_lookup_tcp**\ (), except
3526  *		that it also returns timewait or request sockets. Use
3527  *		**bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
3528  *		full structure.
3529  *
3530  *		This helper is available only if the kernel was compiled with
3531  *		**CONFIG_NET** configuration option.
3532  *	Return
3533  *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3534  *		For sockets with reuseport option, the **struct bpf_sock**
3535  *		result is from *reuse*\ **->socks**\ [] using the hash of the
3536  *		tuple.
3537  *
3538  * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3539  * 	Description
3540  * 		Check whether *iph* and *th* contain a valid SYN cookie ACK for
3541  * 		the listening socket in *sk*.
3542  *
3543  * 		*iph* points to the start of the IPv4 or IPv6 header, while
3544  * 		*iph_len* contains **sizeof**\ (**struct iphdr**) or
3545  * 		**sizeof**\ (**struct ip6hdr**).
3546  *
3547  * 		*th* points to the start of the TCP header, while *th_len*
3548  * 		contains **sizeof**\ (**struct tcphdr**).
3549  * 	Return
3550  * 		0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
3551  * 		error otherwise.
3552  *
3553  * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
3554  *	Description
3555  *		Get name of sysctl in /proc/sys/ and copy it into provided by
3556  *		program buffer *buf* of size *buf_len*.
3557  *
3558  *		The buffer is always NUL terminated, unless it's zero-sized.
3559  *
3560  *		If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
3561  *		copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
3562  *		only (e.g. "tcp_mem").
3563  *	Return
3564  *		Number of character copied (not including the trailing NUL).
3565  *
3566  *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3567  *		truncated name in this case).
3568  *
3569  * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3570  *	Description
3571  *		Get current value of sysctl as it is presented in /proc/sys
3572  *		(incl. newline, etc), and copy it as a string into provided
3573  *		by program buffer *buf* of size *buf_len*.
3574  *
3575  *		The whole value is copied, no matter what file position user
3576  *		space issued e.g. sys_read at.
3577  *
3578  *		The buffer is always NUL terminated, unless it's zero-sized.
3579  *	Return
3580  *		Number of character copied (not including the trailing NUL).
3581  *
3582  *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3583  *		truncated name in this case).
3584  *
3585  *		**-EINVAL** if current value was unavailable, e.g. because
3586  *		sysctl is uninitialized and read returns -EIO for it.
3587  *
3588  * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3589  *	Description
3590  *		Get new value being written by user space to sysctl (before
3591  *		the actual write happens) and copy it as a string into
3592  *		provided by program buffer *buf* of size *buf_len*.
3593  *
3594  *		User space may write new value at file position > 0.
3595  *
3596  *		The buffer is always NUL terminated, unless it's zero-sized.
3597  *	Return
3598  *		Number of character copied (not including the trailing NUL).
3599  *
3600  *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3601  *		truncated name in this case).
3602  *
3603  *		**-EINVAL** if sysctl is being read.
3604  *
3605  * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
3606  *	Description
3607  *		Override new value being written by user space to sysctl with
3608  *		value provided by program in buffer *buf* of size *buf_len*.
3609  *
3610  *		*buf* should contain a string in same form as provided by user
3611  *		space on sysctl write.
3612  *
3613  *		User space may write new value at file position > 0. To override
3614  *		the whole sysctl value file position should be set to zero.
3615  *	Return
3616  *		0 on success.
3617  *
3618  *		**-E2BIG** if the *buf_len* is too big.
3619  *
3620  *		**-EINVAL** if sysctl is being read.
3621  *
3622  * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
3623  *	Description
3624  *		Convert the initial part of the string from buffer *buf* of
3625  *		size *buf_len* to a long integer according to the given base
3626  *		and save the result in *res*.
3627  *
3628  *		The string may begin with an arbitrary amount of white space
3629  *		(as determined by **isspace**\ (3)) followed by a single
3630  *		optional '**-**' sign.
3631  *
3632  *		Five least significant bits of *flags* encode base, other bits
3633  *		are currently unused.
3634  *
3635  *		Base must be either 8, 10, 16 or 0 to detect it automatically
3636  *		similar to user space **strtol**\ (3).
3637  *	Return
3638  *		Number of characters consumed on success. Must be positive but
3639  *		no more than *buf_len*.
3640  *
3641  *		**-EINVAL** if no valid digits were found or unsupported base
3642  *		was provided.
3643  *
3644  *		**-ERANGE** if resulting value was out of range.
3645  *
3646  * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
3647  *	Description
3648  *		Convert the initial part of the string from buffer *buf* of
3649  *		size *buf_len* to an unsigned long integer according to the
3650  *		given base and save the result in *res*.
3651  *
3652  *		The string may begin with an arbitrary amount of white space
3653  *		(as determined by **isspace**\ (3)).
3654  *
3655  *		Five least significant bits of *flags* encode base, other bits
3656  *		are currently unused.
3657  *
3658  *		Base must be either 8, 10, 16 or 0 to detect it automatically
3659  *		similar to user space **strtoul**\ (3).
3660  *	Return
3661  *		Number of characters consumed on success. Must be positive but
3662  *		no more than *buf_len*.
3663  *
3664  *		**-EINVAL** if no valid digits were found or unsupported base
3665  *		was provided.
3666  *
3667  *		**-ERANGE** if resulting value was out of range.
3668  *
3669  * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
3670  *	Description
3671  *		Get a bpf-local-storage from a *sk*.
3672  *
3673  *		Logically, it could be thought of getting the value from
3674  *		a *map* with *sk* as the **key**.  From this
3675  *		perspective,  the usage is not much different from
3676  *		**bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
3677  *		helper enforces the key must be a full socket and the map must
3678  *		be a **BPF_MAP_TYPE_SK_STORAGE** also.
3679  *
3680  *		Underneath, the value is stored locally at *sk* instead of
3681  *		the *map*.  The *map* is used as the bpf-local-storage
3682  *		"type". The bpf-local-storage "type" (i.e. the *map*) is
3683  *		searched against all bpf-local-storages residing at *sk*.
3684  *
3685  *		*sk* is a kernel **struct sock** pointer for LSM program.
3686  *		*sk* is a **struct bpf_sock** pointer for other program types.
3687  *
3688  *		An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
3689  *		used such that a new bpf-local-storage will be
3690  *		created if one does not exist.  *value* can be used
3691  *		together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
3692  *		the initial value of a bpf-local-storage.  If *value* is
3693  *		**NULL**, the new bpf-local-storage will be zero initialized.
3694  *	Return
3695  *		A bpf-local-storage pointer is returned on success.
3696  *
3697  *		**NULL** if not found or there was an error in adding
3698  *		a new bpf-local-storage.
3699  *
3700  * long bpf_sk_storage_delete(struct bpf_map *map, void *sk)
3701  *	Description
3702  *		Delete a bpf-local-storage from a *sk*.
3703  *	Return
3704  *		0 on success.
3705  *
3706  *		**-ENOENT** if the bpf-local-storage cannot be found.
3707  *		**-EINVAL** if sk is not a fullsock (e.g. a request_sock).
3708  *
3709  * long bpf_send_signal(u32 sig)
3710  *	Description
3711  *		Send signal *sig* to the process of the current task.
3712  *		The signal may be delivered to any of this process's threads.
3713  *	Return
3714  *		0 on success or successfully queued.
3715  *
3716  *		**-EBUSY** if work queue under nmi is full.
3717  *
3718  *		**-EINVAL** if *sig* is invalid.
3719  *
3720  *		**-EPERM** if no permission to send the *sig*.
3721  *
3722  *		**-EAGAIN** if bpf program can try again.
3723  *
3724  * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3725  *	Description
3726  *		Try to issue a SYN cookie for the packet with corresponding
3727  *		IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
3728  *
3729  *		*iph* points to the start of the IPv4 or IPv6 header, while
3730  *		*iph_len* contains **sizeof**\ (**struct iphdr**) or
3731  *		**sizeof**\ (**struct ip6hdr**).
3732  *
3733  *		*th* points to the start of the TCP header, while *th_len*
3734  *		contains the length of the TCP header.
3735  *	Return
3736  *		On success, lower 32 bits hold the generated SYN cookie in
3737  *		followed by 16 bits which hold the MSS value for that cookie,
3738  *		and the top 16 bits are unused.
3739  *
3740  *		On failure, the returned value is one of the following:
3741  *
3742  *		**-EINVAL** SYN cookie cannot be issued due to error
3743  *
3744  *		**-ENOENT** SYN cookie should not be issued (no SYN flood)
3745  *
3746  *		**-EOPNOTSUPP** kernel configuration does not enable SYN cookies
3747  *
3748  *		**-EPROTONOSUPPORT** IP packet version is not 4 or 6
3749  *
3750  * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3751  * 	Description
3752  * 		Write raw *data* blob into a special BPF perf event held by
3753  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3754  * 		event must have the following attributes: **PERF_SAMPLE_RAW**
3755  * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3756  * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3757  *
3758  * 		The *flags* are used to indicate the index in *map* for which
3759  * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
3760  * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3761  * 		to indicate that the index of the current CPU core should be
3762  * 		used.
3763  *
3764  * 		The value to write, of *size*, is passed through eBPF stack and
3765  * 		pointed by *data*.
3766  *
3767  * 		*ctx* is a pointer to in-kernel struct sk_buff.
3768  *
3769  * 		This helper is similar to **bpf_perf_event_output**\ () but
3770  * 		restricted to raw_tracepoint bpf programs.
3771  * 	Return
3772  * 		0 on success, or a negative error in case of failure.
3773  *
3774  * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr)
3775  * 	Description
3776  * 		Safely attempt to read *size* bytes from user space address
3777  * 		*unsafe_ptr* and store the data in *dst*.
3778  * 	Return
3779  * 		0 on success, or a negative error in case of failure.
3780  *
3781  * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
3782  * 	Description
3783  * 		Safely attempt to read *size* bytes from kernel space address
3784  * 		*unsafe_ptr* and store the data in *dst*.
3785  * 	Return
3786  * 		0 on success, or a negative error in case of failure.
3787  *
3788  * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr)
3789  * 	Description
3790  * 		Copy a NUL terminated string from an unsafe user address
3791  * 		*unsafe_ptr* to *dst*. The *size* should include the
3792  * 		terminating NUL byte. In case the string length is smaller than
3793  * 		*size*, the target is not padded with further NUL bytes. If the
3794  * 		string length is larger than *size*, just *size*-1 bytes are
3795  * 		copied and the last byte is set to NUL.
3796  *
3797  * 		On success, returns the number of bytes that were written,
3798  * 		including the terminal NUL. This makes this helper useful in
3799  * 		tracing programs for reading strings, and more importantly to
3800  * 		get its length at runtime. See the following snippet:
3801  *
3802  * 		::
3803  *
3804  * 			SEC("kprobe/sys_open")
3805  * 			void bpf_sys_open(struct pt_regs *ctx)
3806  * 			{
3807  * 			        char buf[PATHLEN]; // PATHLEN is defined to 256
3808  * 			        int res = bpf_probe_read_user_str(buf, sizeof(buf),
3809  * 				                                  ctx->di);
3810  *
3811  * 				// Consume buf, for example push it to
3812  * 				// userspace via bpf_perf_event_output(); we
3813  * 				// can use res (the string length) as event
3814  * 				// size, after checking its boundaries.
3815  * 			}
3816  *
3817  * 		In comparison, using **bpf_probe_read_user**\ () helper here
3818  * 		instead to read the string would require to estimate the length
3819  * 		at compile time, and would often result in copying more memory
3820  * 		than necessary.
3821  *
3822  * 		Another useful use case is when parsing individual process
3823  * 		arguments or individual environment variables navigating
3824  * 		*current*\ **->mm->arg_start** and *current*\
3825  * 		**->mm->env_start**: using this helper and the return value,
3826  * 		one can quickly iterate at the right offset of the memory area.
3827  * 	Return
3828  * 		On success, the strictly positive length of the output string,
3829  * 		including the trailing NUL character. On error, a negative
3830  * 		value.
3831  *
3832  * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr)
3833  * 	Description
3834  * 		Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
3835  * 		to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
3836  * 	Return
3837  * 		On success, the strictly positive length of the string, including
3838  * 		the trailing NUL character. On error, a negative value.
3839  *
3840  * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
3841  *	Description
3842  *		Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
3843  *		*rcv_nxt* is the ack_seq to be sent out.
3844  *	Return
3845  *		0 on success, or a negative error in case of failure.
3846  *
3847  * long bpf_send_signal_thread(u32 sig)
3848  *	Description
3849  *		Send signal *sig* to the thread corresponding to the current task.
3850  *	Return
3851  *		0 on success or successfully queued.
3852  *
3853  *		**-EBUSY** if work queue under nmi is full.
3854  *
3855  *		**-EINVAL** if *sig* is invalid.
3856  *
3857  *		**-EPERM** if no permission to send the *sig*.
3858  *
3859  *		**-EAGAIN** if bpf program can try again.
3860  *
3861  * u64 bpf_jiffies64(void)
3862  *	Description
3863  *		Obtain the 64bit jiffies
3864  *	Return
3865  *		The 64 bit jiffies
3866  *
3867  * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
3868  *	Description
3869  *		For an eBPF program attached to a perf event, retrieve the
3870  *		branch records (**struct perf_branch_entry**) associated to *ctx*
3871  *		and store it in the buffer pointed by *buf* up to size
3872  *		*size* bytes.
3873  *	Return
3874  *		On success, number of bytes written to *buf*. On error, a
3875  *		negative value.
3876  *
3877  *		The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
3878  *		instead return the number of bytes required to store all the
3879  *		branch entries. If this flag is set, *buf* may be NULL.
3880  *
3881  *		**-EINVAL** if arguments invalid or **size** not a multiple
3882  *		of **sizeof**\ (**struct perf_branch_entry**\ ).
3883  *
3884  *		**-ENOENT** if architecture does not support branch records.
3885  *
3886  * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
3887  *	Description
3888  *		Returns 0 on success, values for *pid* and *tgid* as seen from the current
3889  *		*namespace* will be returned in *nsdata*.
3890  *	Return
3891  *		0 on success, or one of the following in case of failure:
3892  *
3893  *		**-EINVAL** if dev and inum supplied don't match dev_t and inode number
3894  *              with nsfs of current task, or if dev conversion to dev_t lost high bits.
3895  *
3896  *		**-ENOENT** if pidns does not exists for the current task.
3897  *
3898  * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3899  *	Description
3900  *		Write raw *data* blob into a special BPF perf event held by
3901  *		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3902  *		event must have the following attributes: **PERF_SAMPLE_RAW**
3903  *		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3904  *		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3905  *
3906  *		The *flags* are used to indicate the index in *map* for which
3907  *		the value must be put, masked with **BPF_F_INDEX_MASK**.
3908  *		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3909  *		to indicate that the index of the current CPU core should be
3910  *		used.
3911  *
3912  *		The value to write, of *size*, is passed through eBPF stack and
3913  *		pointed by *data*.
3914  *
3915  *		*ctx* is a pointer to in-kernel struct xdp_buff.
3916  *
3917  *		This helper is similar to **bpf_perf_eventoutput**\ () but
3918  *		restricted to raw_tracepoint bpf programs.
3919  *	Return
3920  *		0 on success, or a negative error in case of failure.
3921  *
3922  * u64 bpf_get_netns_cookie(void *ctx)
3923  * 	Description
3924  * 		Retrieve the cookie (generated by the kernel) of the network
3925  * 		namespace the input *ctx* is associated with. The network
3926  * 		namespace cookie remains stable for its lifetime and provides
3927  * 		a global identifier that can be assumed unique. If *ctx* is
3928  * 		NULL, then the helper returns the cookie for the initial
3929  * 		network namespace. The cookie itself is very similar to that
3930  * 		of **bpf_get_socket_cookie**\ () helper, but for network
3931  * 		namespaces instead of sockets.
3932  * 	Return
3933  * 		A 8-byte long opaque number.
3934  *
3935  * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
3936  * 	Description
3937  * 		Return id of cgroup v2 that is ancestor of the cgroup associated
3938  * 		with the current task at the *ancestor_level*. The root cgroup
3939  * 		is at *ancestor_level* zero and each step down the hierarchy
3940  * 		increments the level. If *ancestor_level* == level of cgroup
3941  * 		associated with the current task, then return value will be the
3942  * 		same as that of **bpf_get_current_cgroup_id**\ ().
3943  *
3944  * 		The helper is useful to implement policies based on cgroups
3945  * 		that are upper in hierarchy than immediate cgroup associated
3946  * 		with the current task.
3947  *
3948  * 		The format of returned id and helper limitations are same as in
3949  * 		**bpf_get_current_cgroup_id**\ ().
3950  * 	Return
3951  * 		The id is returned or 0 in case the id could not be retrieved.
3952  *
3953  * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
3954  *	Description
3955  *		Helper is overloaded depending on BPF program type. This
3956  *		description applies to **BPF_PROG_TYPE_SCHED_CLS** and
3957  *		**BPF_PROG_TYPE_SCHED_ACT** programs.
3958  *
3959  *		Assign the *sk* to the *skb*. When combined with appropriate
3960  *		routing configuration to receive the packet towards the socket,
3961  *		will cause *skb* to be delivered to the specified socket.
3962  *		Subsequent redirection of *skb* via  **bpf_redirect**\ (),
3963  *		**bpf_clone_redirect**\ () or other methods outside of BPF may
3964  *		interfere with successful delivery to the socket.
3965  *
3966  *		This operation is only valid from TC ingress path.
3967  *
3968  *		The *flags* argument must be zero.
3969  *	Return
3970  *		0 on success, or a negative error in case of failure:
3971  *
3972  *		**-EINVAL** if specified *flags* are not supported.
3973  *
3974  *		**-ENOENT** if the socket is unavailable for assignment.
3975  *
3976  *		**-ENETUNREACH** if the socket is unreachable (wrong netns).
3977  *
3978  *		**-EOPNOTSUPP** if the operation is not supported, for example
3979  *		a call from outside of TC ingress.
3980  *
3981  *		**-ESOCKTNOSUPPORT** if the socket type is not supported
3982  *		(reuseport).
3983  *
3984  * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags)
3985  *	Description
3986  *		Helper is overloaded depending on BPF program type. This
3987  *		description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs.
3988  *
3989  *		Select the *sk* as a result of a socket lookup.
3990  *
3991  *		For the operation to succeed passed socket must be compatible
3992  *		with the packet description provided by the *ctx* object.
3993  *
3994  *		L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must
3995  *		be an exact match. While IP family (**AF_INET** or
3996  *		**AF_INET6**) must be compatible, that is IPv6 sockets
3997  *		that are not v6-only can be selected for IPv4 packets.
3998  *
3999  *		Only TCP listeners and UDP unconnected sockets can be
4000  *		selected. *sk* can also be NULL to reset any previous
4001  *		selection.
4002  *
4003  *		*flags* argument can combination of following values:
4004  *
4005  *		* **BPF_SK_LOOKUP_F_REPLACE** to override the previous
4006  *		  socket selection, potentially done by a BPF program
4007  *		  that ran before us.
4008  *
4009  *		* **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip
4010  *		  load-balancing within reuseport group for the socket
4011  *		  being selected.
4012  *
4013  *		On success *ctx->sk* will point to the selected socket.
4014  *
4015  *	Return
4016  *		0 on success, or a negative errno in case of failure.
4017  *
4018  *		* **-EAFNOSUPPORT** if socket family (*sk->family*) is
4019  *		  not compatible with packet family (*ctx->family*).
4020  *
4021  *		* **-EEXIST** if socket has been already selected,
4022  *		  potentially by another program, and
4023  *		  **BPF_SK_LOOKUP_F_REPLACE** flag was not specified.
4024  *
4025  *		* **-EINVAL** if unsupported flags were specified.
4026  *
4027  *		* **-EPROTOTYPE** if socket L4 protocol
4028  *		  (*sk->protocol*) doesn't match packet protocol
4029  *		  (*ctx->protocol*).
4030  *
4031  *		* **-ESOCKTNOSUPPORT** if socket is not in allowed
4032  *		  state (TCP listening or UDP unconnected).
4033  *
4034  * u64 bpf_ktime_get_boot_ns(void)
4035  * 	Description
4036  * 		Return the time elapsed since system boot, in nanoseconds.
4037  * 		Does include the time the system was suspended.
4038  * 		See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
4039  * 	Return
4040  * 		Current *ktime*.
4041  *
4042  * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4043  * 	Description
4044  * 		**bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
4045  * 		out the format string.
4046  * 		The *m* represents the seq_file. The *fmt* and *fmt_size* are for
4047  * 		the format string itself. The *data* and *data_len* are format string
4048  * 		arguments. The *data* are a **u64** array and corresponding format string
4049  * 		values are stored in the array. For strings and pointers where pointees
4050  * 		are accessed, only the pointer values are stored in the *data* array.
4051  * 		The *data_len* is the size of *data* in bytes.
4052  *
4053  *		Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
4054  *		Reading kernel memory may fail due to either invalid address or
4055  *		valid address but requiring a major memory fault. If reading kernel memory
4056  *		fails, the string for **%s** will be an empty string, and the ip
4057  *		address for **%p{i,I}{4,6}** will be 0. Not returning error to
4058  *		bpf program is consistent with what **bpf_trace_printk**\ () does for now.
4059  * 	Return
4060  * 		0 on success, or a negative error in case of failure:
4061  *
4062  *		**-EBUSY** if per-CPU memory copy buffer is busy, can try again
4063  *		by returning 1 from bpf program.
4064  *
4065  *		**-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
4066  *
4067  *		**-E2BIG** if *fmt* contains too many format specifiers.
4068  *
4069  *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
4070  *
4071  * long bpf_seq_write(struct seq_file *m, const void *data, u32 len)
4072  * 	Description
4073  * 		**bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
4074  * 		The *m* represents the seq_file. The *data* and *len* represent the
4075  * 		data to write in bytes.
4076  * 	Return
4077  * 		0 on success, or a negative error in case of failure:
4078  *
4079  *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
4080  *
4081  * u64 bpf_sk_cgroup_id(void *sk)
4082  *	Description
4083  *		Return the cgroup v2 id of the socket *sk*.
4084  *
4085  *		*sk* must be a non-**NULL** pointer to a socket, e.g. one
4086  *		returned from **bpf_sk_lookup_xxx**\ (),
4087  *		**bpf_sk_fullsock**\ (), etc. The format of returned id is
4088  *		same as in **bpf_skb_cgroup_id**\ ().
4089  *
4090  *		This helper is available only if the kernel was compiled with
4091  *		the **CONFIG_SOCK_CGROUP_DATA** configuration option.
4092  *	Return
4093  *		The id is returned or 0 in case the id could not be retrieved.
4094  *
4095  * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
4096  *	Description
4097  *		Return id of cgroup v2 that is ancestor of cgroup associated
4098  *		with the *sk* at the *ancestor_level*.  The root cgroup is at
4099  *		*ancestor_level* zero and each step down the hierarchy
4100  *		increments the level. If *ancestor_level* == level of cgroup
4101  *		associated with *sk*, then return value will be same as that
4102  *		of **bpf_sk_cgroup_id**\ ().
4103  *
4104  *		The helper is useful to implement policies based on cgroups
4105  *		that are upper in hierarchy than immediate cgroup associated
4106  *		with *sk*.
4107  *
4108  *		The format of returned id and helper limitations are same as in
4109  *		**bpf_sk_cgroup_id**\ ().
4110  *	Return
4111  *		The id is returned or 0 in case the id could not be retrieved.
4112  *
4113  * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
4114  * 	Description
4115  * 		Copy *size* bytes from *data* into a ring buffer *ringbuf*.
4116  * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4117  * 		of new data availability is sent.
4118  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4119  * 		of new data availability is sent unconditionally.
4120  * 		If **0** is specified in *flags*, an adaptive notification
4121  * 		of new data availability is sent.
4122  *
4123  * 		An adaptive notification is a notification sent whenever the user-space
4124  * 		process has caught up and consumed all available payloads. In case the user-space
4125  * 		process is still processing a previous payload, then no notification is needed
4126  * 		as it will process the newly added payload automatically.
4127  * 	Return
4128  * 		0 on success, or a negative error in case of failure.
4129  *
4130  * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
4131  * 	Description
4132  * 		Reserve *size* bytes of payload in a ring buffer *ringbuf*.
4133  * 		*flags* must be 0.
4134  * 	Return
4135  * 		Valid pointer with *size* bytes of memory available; NULL,
4136  * 		otherwise.
4137  *
4138  * void bpf_ringbuf_submit(void *data, u64 flags)
4139  * 	Description
4140  * 		Submit reserved ring buffer sample, pointed to by *data*.
4141  * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4142  * 		of new data availability is sent.
4143  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4144  * 		of new data availability is sent unconditionally.
4145  * 		If **0** is specified in *flags*, an adaptive notification
4146  * 		of new data availability is sent.
4147  *
4148  * 		See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4149  * 	Return
4150  * 		Nothing. Always succeeds.
4151  *
4152  * void bpf_ringbuf_discard(void *data, u64 flags)
4153  * 	Description
4154  * 		Discard reserved ring buffer sample, pointed to by *data*.
4155  * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4156  * 		of new data availability is sent.
4157  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4158  * 		of new data availability is sent unconditionally.
4159  * 		If **0** is specified in *flags*, an adaptive notification
4160  * 		of new data availability is sent.
4161  *
4162  * 		See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4163  * 	Return
4164  * 		Nothing. Always succeeds.
4165  *
4166  * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
4167  *	Description
4168  *		Query various characteristics of provided ring buffer. What
4169  *		exactly is queries is determined by *flags*:
4170  *
4171  *		* **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
4172  *		* **BPF_RB_RING_SIZE**: The size of ring buffer.
4173  *		* **BPF_RB_CONS_POS**: Consumer position (can wrap around).
4174  *		* **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
4175  *
4176  *		Data returned is just a momentary snapshot of actual values
4177  *		and could be inaccurate, so this facility should be used to
4178  *		power heuristics and for reporting, not to make 100% correct
4179  *		calculation.
4180  *	Return
4181  *		Requested value, or 0, if *flags* are not recognized.
4182  *
4183  * long bpf_csum_level(struct sk_buff *skb, u64 level)
4184  * 	Description
4185  * 		Change the skbs checksum level by one layer up or down, or
4186  * 		reset it entirely to none in order to have the stack perform
4187  * 		checksum validation. The level is applicable to the following
4188  * 		protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
4189  * 		| ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
4190  * 		through **bpf_skb_adjust_room**\ () helper with passing in
4191  * 		**BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one	call
4192  * 		to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
4193  * 		the UDP header is removed. Similarly, an encap of the latter
4194  * 		into the former could be accompanied by a helper call to
4195  * 		**bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
4196  * 		skb is still intended to be processed in higher layers of the
4197  * 		stack instead of just egressing at tc.
4198  *
4199  * 		There are three supported level settings at this time:
4200  *
4201  * 		* **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
4202  * 		  with CHECKSUM_UNNECESSARY.
4203  * 		* **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
4204  * 		  with CHECKSUM_UNNECESSARY.
4205  * 		* **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
4206  * 		  sets CHECKSUM_NONE to force checksum validation by the stack.
4207  * 		* **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
4208  * 		  skb->csum_level.
4209  * 	Return
4210  * 		0 on success, or a negative error in case of failure. In the
4211  * 		case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
4212  * 		is returned or the error code -EACCES in case the skb is not
4213  * 		subject to CHECKSUM_UNNECESSARY.
4214  *
4215  * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk)
4216  *	Description
4217  *		Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
4218  *	Return
4219  *		*sk* if casting is valid, or **NULL** otherwise.
4220  *
4221  * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)
4222  *	Description
4223  *		Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
4224  *	Return
4225  *		*sk* if casting is valid, or **NULL** otherwise.
4226  *
4227  * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)
4228  * 	Description
4229  *		Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
4230  *	Return
4231  *		*sk* if casting is valid, or **NULL** otherwise.
4232  *
4233  * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)
4234  * 	Description
4235  *		Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
4236  *	Return
4237  *		*sk* if casting is valid, or **NULL** otherwise.
4238  *
4239  * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
4240  * 	Description
4241  *		Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
4242  *	Return
4243  *		*sk* if casting is valid, or **NULL** otherwise.
4244  *
4245  * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags)
4246  *	Description
4247  *		Return a user or a kernel stack in bpf program provided buffer.
4248  *		Note: the user stack will only be populated if the *task* is
4249  *		the current task; all other tasks will return -EOPNOTSUPP.
4250  *		To achieve this, the helper needs *task*, which is a valid
4251  *		pointer to **struct task_struct**. To store the stacktrace, the
4252  *		bpf program provides *buf* with a nonnegative *size*.
4253  *
4254  *		The last argument, *flags*, holds the number of stack frames to
4255  *		skip (from 0 to 255), masked with
4256  *		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
4257  *		the following flags:
4258  *
4259  *		**BPF_F_USER_STACK**
4260  *			Collect a user space stack instead of a kernel stack.
4261  *			The *task* must be the current task.
4262  *		**BPF_F_USER_BUILD_ID**
4263  *			Collect buildid+offset instead of ips for user stack,
4264  *			only valid if **BPF_F_USER_STACK** is also specified.
4265  *
4266  *		**bpf_get_task_stack**\ () can collect up to
4267  *		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
4268  *		to sufficient large buffer size. Note that
4269  *		this limit can be controlled with the **sysctl** program, and
4270  *		that it should be manually increased in order to profile long
4271  *		user stacks (such as stacks for Java programs). To do so, use:
4272  *
4273  *		::
4274  *
4275  *			# sysctl kernel.perf_event_max_stack=<new value>
4276  *	Return
4277  *		A non-negative value equal to or less than *size* on success,
4278  *		or a negative error in case of failure.
4279  *
4280  * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags)
4281  *	Description
4282  *		Load header option.  Support reading a particular TCP header
4283  *		option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
4284  *
4285  *		If *flags* is 0, it will search the option from the
4286  *		*skops*\ **->skb_data**.  The comment in **struct bpf_sock_ops**
4287  *		has details on what skb_data contains under different
4288  *		*skops*\ **->op**.
4289  *
4290  *		The first byte of the *searchby_res* specifies the
4291  *		kind that it wants to search.
4292  *
4293  *		If the searching kind is an experimental kind
4294  *		(i.e. 253 or 254 according to RFC6994).  It also
4295  *		needs to specify the "magic" which is either
4296  *		2 bytes or 4 bytes.  It then also needs to
4297  *		specify the size of the magic by using
4298  *		the 2nd byte which is "kind-length" of a TCP
4299  *		header option and the "kind-length" also
4300  *		includes the first 2 bytes "kind" and "kind-length"
4301  *		itself as a normal TCP header option also does.
4302  *
4303  *		For example, to search experimental kind 254 with
4304  *		2 byte magic 0xeB9F, the searchby_res should be
4305  *		[ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
4306  *
4307  *		To search for the standard window scale option (3),
4308  *		the *searchby_res* should be [ 3, 0, 0, .... 0 ].
4309  *		Note, kind-length must be 0 for regular option.
4310  *
4311  *		Searching for No-Op (0) and End-of-Option-List (1) are
4312  *		not supported.
4313  *
4314  *		*len* must be at least 2 bytes which is the minimal size
4315  *		of a header option.
4316  *
4317  *		Supported flags:
4318  *
4319  *		* **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
4320  *		  saved_syn packet or the just-received syn packet.
4321  *
4322  *	Return
4323  *		> 0 when found, the header option is copied to *searchby_res*.
4324  *		The return value is the total length copied. On failure, a
4325  *		negative error code is returned:
4326  *
4327  *		**-EINVAL** if a parameter is invalid.
4328  *
4329  *		**-ENOMSG** if the option is not found.
4330  *
4331  *		**-ENOENT** if no syn packet is available when
4332  *		**BPF_LOAD_HDR_OPT_TCP_SYN** is used.
4333  *
4334  *		**-ENOSPC** if there is not enough space.  Only *len* number of
4335  *		bytes are copied.
4336  *
4337  *		**-EFAULT** on failure to parse the header options in the
4338  *		packet.
4339  *
4340  *		**-EPERM** if the helper cannot be used under the current
4341  *		*skops*\ **->op**.
4342  *
4343  * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags)
4344  *	Description
4345  *		Store header option.  The data will be copied
4346  *		from buffer *from* with length *len* to the TCP header.
4347  *
4348  *		The buffer *from* should have the whole option that
4349  *		includes the kind, kind-length, and the actual
4350  *		option data.  The *len* must be at least kind-length
4351  *		long.  The kind-length does not have to be 4 byte
4352  *		aligned.  The kernel will take care of the padding
4353  *		and setting the 4 bytes aligned value to th->doff.
4354  *
4355  *		This helper will check for duplicated option
4356  *		by searching the same option in the outgoing skb.
4357  *
4358  *		This helper can only be called during
4359  *		**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4360  *
4361  *	Return
4362  *		0 on success, or negative error in case of failure:
4363  *
4364  *		**-EINVAL** If param is invalid.
4365  *
4366  *		**-ENOSPC** if there is not enough space in the header.
4367  *		Nothing has been written
4368  *
4369  *		**-EEXIST** if the option already exists.
4370  *
4371  *		**-EFAULT** on failrue to parse the existing header options.
4372  *
4373  *		**-EPERM** if the helper cannot be used under the current
4374  *		*skops*\ **->op**.
4375  *
4376  * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
4377  *	Description
4378  *		Reserve *len* bytes for the bpf header option.  The
4379  *		space will be used by **bpf_store_hdr_opt**\ () later in
4380  *		**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4381  *
4382  *		If **bpf_reserve_hdr_opt**\ () is called multiple times,
4383  *		the total number of bytes will be reserved.
4384  *
4385  *		This helper can only be called during
4386  *		**BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
4387  *
4388  *	Return
4389  *		0 on success, or negative error in case of failure:
4390  *
4391  *		**-EINVAL** if a parameter is invalid.
4392  *
4393  *		**-ENOSPC** if there is not enough space in the header.
4394  *
4395  *		**-EPERM** if the helper cannot be used under the current
4396  *		*skops*\ **->op**.
4397  *
4398  * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
4399  *	Description
4400  *		Get a bpf_local_storage from an *inode*.
4401  *
4402  *		Logically, it could be thought of as getting the value from
4403  *		a *map* with *inode* as the **key**.  From this
4404  *		perspective,  the usage is not much different from
4405  *		**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
4406  *		helper enforces the key must be an inode and the map must also
4407  *		be a **BPF_MAP_TYPE_INODE_STORAGE**.
4408  *
4409  *		Underneath, the value is stored locally at *inode* instead of
4410  *		the *map*.  The *map* is used as the bpf-local-storage
4411  *		"type". The bpf-local-storage "type" (i.e. the *map*) is
4412  *		searched against all bpf_local_storage residing at *inode*.
4413  *
4414  *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4415  *		used such that a new bpf_local_storage will be
4416  *		created if one does not exist.  *value* can be used
4417  *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4418  *		the initial value of a bpf_local_storage.  If *value* is
4419  *		**NULL**, the new bpf_local_storage will be zero initialized.
4420  *	Return
4421  *		A bpf_local_storage pointer is returned on success.
4422  *
4423  *		**NULL** if not found or there was an error in adding
4424  *		a new bpf_local_storage.
4425  *
4426  * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
4427  *	Description
4428  *		Delete a bpf_local_storage from an *inode*.
4429  *	Return
4430  *		0 on success.
4431  *
4432  *		**-ENOENT** if the bpf_local_storage cannot be found.
4433  *
4434  * long bpf_d_path(struct path *path, char *buf, u32 sz)
4435  *	Description
4436  *		Return full path for given **struct path** object, which
4437  *		needs to be the kernel BTF *path* object. The path is
4438  *		returned in the provided buffer *buf* of size *sz* and
4439  *		is zero terminated.
4440  *
4441  *	Return
4442  *		On success, the strictly positive length of the string,
4443  *		including the trailing NUL character. On error, a negative
4444  *		value.
4445  *
4446  * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
4447  * 	Description
4448  * 		Read *size* bytes from user space address *user_ptr* and store
4449  * 		the data in *dst*. This is a wrapper of **copy_from_user**\ ().
4450  * 	Return
4451  * 		0 on success, or a negative error in case of failure.
4452  *
4453  * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
4454  *	Description
4455  *		Use BTF to store a string representation of *ptr*->ptr in *str*,
4456  *		using *ptr*->type_id.  This value should specify the type
4457  *		that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
4458  *		can be used to look up vmlinux BTF type ids. Traversing the
4459  *		data structure using BTF, the type information and values are
4460  *		stored in the first *str_size* - 1 bytes of *str*.  Safe copy of
4461  *		the pointer data is carried out to avoid kernel crashes during
4462  *		operation.  Smaller types can use string space on the stack;
4463  *		larger programs can use map data to store the string
4464  *		representation.
4465  *
4466  *		The string can be subsequently shared with userspace via
4467  *		bpf_perf_event_output() or ring buffer interfaces.
4468  *		bpf_trace_printk() is to be avoided as it places too small
4469  *		a limit on string size to be useful.
4470  *
4471  *		*flags* is a combination of
4472  *
4473  *		**BTF_F_COMPACT**
4474  *			no formatting around type information
4475  *		**BTF_F_NONAME**
4476  *			no struct/union member names/types
4477  *		**BTF_F_PTR_RAW**
4478  *			show raw (unobfuscated) pointer values;
4479  *			equivalent to printk specifier %px.
4480  *		**BTF_F_ZERO**
4481  *			show zero-valued struct/union members; they
4482  *			are not displayed by default
4483  *
4484  *	Return
4485  *		The number of bytes that were written (or would have been
4486  *		written if output had to be truncated due to string size),
4487  *		or a negative error in cases of failure.
4488  *
4489  * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags)
4490  *	Description
4491  *		Use BTF to write to seq_write a string representation of
4492  *		*ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
4493  *		*flags* are identical to those used for bpf_snprintf_btf.
4494  *	Return
4495  *		0 on success or a negative error in case of failure.
4496  *
4497  * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
4498  * 	Description
4499  * 		See **bpf_get_cgroup_classid**\ () for the main description.
4500  * 		This helper differs from **bpf_get_cgroup_classid**\ () in that
4501  * 		the cgroup v1 net_cls class is retrieved only from the *skb*'s
4502  * 		associated socket instead of the current process.
4503  * 	Return
4504  * 		The id is returned or 0 in case the id could not be retrieved.
4505  *
4506  * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
4507  * 	Description
4508  * 		Redirect the packet to another net device of index *ifindex*
4509  * 		and fill in L2 addresses from neighboring subsystem. This helper
4510  * 		is somewhat similar to **bpf_redirect**\ (), except that it
4511  * 		populates L2 addresses as well, meaning, internally, the helper
4512  * 		relies on the neighbor lookup for the L2 address of the nexthop.
4513  *
4514  * 		The helper will perform a FIB lookup based on the skb's
4515  * 		networking header to get the address of the next hop, unless
4516  * 		this is supplied by the caller in the *params* argument. The
4517  * 		*plen* argument indicates the len of *params* and should be set
4518  * 		to 0 if *params* is NULL.
4519  *
4520  * 		The *flags* argument is reserved and must be 0. The helper is
4521  * 		currently only supported for tc BPF program types, and enabled
4522  * 		for IPv4 and IPv6 protocols.
4523  * 	Return
4524  * 		The helper returns **TC_ACT_REDIRECT** on success or
4525  * 		**TC_ACT_SHOT** on error.
4526  *
4527  * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu)
4528  *     Description
4529  *             Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4530  *             pointer to the percpu kernel variable on *cpu*. A ksym is an
4531  *             extern variable decorated with '__ksym'. For ksym, there is a
4532  *             global var (either static or global) defined of the same name
4533  *             in the kernel. The ksym is percpu if the global var is percpu.
4534  *             The returned pointer points to the global percpu var on *cpu*.
4535  *
4536  *             bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
4537  *             kernel, except that bpf_per_cpu_ptr() may return NULL. This
4538  *             happens if *cpu* is larger than nr_cpu_ids. The caller of
4539  *             bpf_per_cpu_ptr() must check the returned value.
4540  *     Return
4541  *             A pointer pointing to the kernel percpu variable on *cpu*, or
4542  *             NULL, if *cpu* is invalid.
4543  *
4544  * void *bpf_this_cpu_ptr(const void *percpu_ptr)
4545  *	Description
4546  *		Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4547  *		pointer to the percpu kernel variable on this cpu. See the
4548  *		description of 'ksym' in **bpf_per_cpu_ptr**\ ().
4549  *
4550  *		bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
4551  *		the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
4552  *		never return NULL.
4553  *	Return
4554  *		A pointer pointing to the kernel percpu variable on this cpu.
4555  *
4556  * long bpf_redirect_peer(u32 ifindex, u64 flags)
4557  * 	Description
4558  * 		Redirect the packet to another net device of index *ifindex*.
4559  * 		This helper is somewhat similar to **bpf_redirect**\ (), except
4560  * 		that the redirection happens to the *ifindex*' peer device and
4561  * 		the netns switch takes place from ingress to ingress without
4562  * 		going through the CPU's backlog queue.
4563  *
4564  * 		The *flags* argument is reserved and must be 0. The helper is
4565  * 		currently only supported for tc BPF program types at the ingress
4566  * 		hook and for veth device types. The peer device must reside in a
4567  * 		different network namespace.
4568  * 	Return
4569  * 		The helper returns **TC_ACT_REDIRECT** on success or
4570  * 		**TC_ACT_SHOT** on error.
4571  *
4572  * void *bpf_task_storage_get(struct bpf_map *map, struct task_struct *task, void *value, u64 flags)
4573  *	Description
4574  *		Get a bpf_local_storage from the *task*.
4575  *
4576  *		Logically, it could be thought of as getting the value from
4577  *		a *map* with *task* as the **key**.  From this
4578  *		perspective,  the usage is not much different from
4579  *		**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
4580  *		helper enforces the key must be an task_struct and the map must also
4581  *		be a **BPF_MAP_TYPE_TASK_STORAGE**.
4582  *
4583  *		Underneath, the value is stored locally at *task* instead of
4584  *		the *map*.  The *map* is used as the bpf-local-storage
4585  *		"type". The bpf-local-storage "type" (i.e. the *map*) is
4586  *		searched against all bpf_local_storage residing at *task*.
4587  *
4588  *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4589  *		used such that a new bpf_local_storage will be
4590  *		created if one does not exist.  *value* can be used
4591  *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4592  *		the initial value of a bpf_local_storage.  If *value* is
4593  *		**NULL**, the new bpf_local_storage will be zero initialized.
4594  *	Return
4595  *		A bpf_local_storage pointer is returned on success.
4596  *
4597  *		**NULL** if not found or there was an error in adding
4598  *		a new bpf_local_storage.
4599  *
4600  * long bpf_task_storage_delete(struct bpf_map *map, struct task_struct *task)
4601  *	Description
4602  *		Delete a bpf_local_storage from a *task*.
4603  *	Return
4604  *		0 on success.
4605  *
4606  *		**-ENOENT** if the bpf_local_storage cannot be found.
4607  *
4608  * struct task_struct *bpf_get_current_task_btf(void)
4609  *	Description
4610  *		Return a BTF pointer to the "current" task.
4611  *		This pointer can also be used in helpers that accept an
4612  *		*ARG_PTR_TO_BTF_ID* of type *task_struct*.
4613  *	Return
4614  *		Pointer to the current task.
4615  *
4616  * long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
4617  *	Description
4618  *		Set or clear certain options on *bprm*:
4619  *
4620  *		**BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
4621  *		which sets the **AT_SECURE** auxv for glibc. The bit
4622  *		is cleared if the flag is not specified.
4623  *	Return
4624  *		**-EINVAL** if invalid *flags* are passed, zero otherwise.
4625  *
4626  * u64 bpf_ktime_get_coarse_ns(void)
4627  * 	Description
4628  * 		Return a coarse-grained version of the time elapsed since
4629  * 		system boot, in nanoseconds. Does not include time the system
4630  * 		was suspended.
4631  *
4632  * 		See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
4633  * 	Return
4634  * 		Current *ktime*.
4635  *
4636  * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size)
4637  *	Description
4638  *		Returns the stored IMA hash of the *inode* (if it's avaialable).
4639  *		If the hash is larger than *size*, then only *size*
4640  *		bytes will be copied to *dst*
4641  *	Return
4642  *		The **hash_algo** is returned on success,
4643  *		**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
4644  *		invalid arguments are passed.
4645  *
4646  * struct socket *bpf_sock_from_file(struct file *file)
4647  *	Description
4648  *		If the given file represents a socket, returns the associated
4649  *		socket.
4650  *	Return
4651  *		A pointer to a struct socket on success or NULL if the file is
4652  *		not a socket.
4653  *
4654  * long bpf_check_mtu(void *ctx, u32 ifindex, u32 *mtu_len, s32 len_diff, u64 flags)
4655  *	Description
4656  *		Check packet size against exceeding MTU of net device (based
4657  *		on *ifindex*).  This helper will likely be used in combination
4658  *		with helpers that adjust/change the packet size.
4659  *
4660  *		The argument *len_diff* can be used for querying with a planned
4661  *		size change. This allows to check MTU prior to changing packet
4662  *		ctx. Providing an *len_diff* adjustment that is larger than the
4663  *		actual packet size (resulting in negative packet size) will in
4664  *		principle not exceed the MTU, why it is not considered a
4665  *		failure.  Other BPF-helpers are needed for performing the
4666  *		planned size change, why the responsability for catch a negative
4667  *		packet size belong in those helpers.
4668  *
4669  *		Specifying *ifindex* zero means the MTU check is performed
4670  *		against the current net device.  This is practical if this isn't
4671  *		used prior to redirect.
4672  *
4673  *		On input *mtu_len* must be a valid pointer, else verifier will
4674  *		reject BPF program.  If the value *mtu_len* is initialized to
4675  *		zero then the ctx packet size is use.  When value *mtu_len* is
4676  *		provided as input this specify the L3 length that the MTU check
4677  *		is done against. Remember XDP and TC length operate at L2, but
4678  *		this value is L3 as this correlate to MTU and IP-header tot_len
4679  *		values which are L3 (similar behavior as bpf_fib_lookup).
4680  *
4681  *		The Linux kernel route table can configure MTUs on a more
4682  *		specific per route level, which is not provided by this helper.
4683  *		For route level MTU checks use the **bpf_fib_lookup**\ ()
4684  *		helper.
4685  *
4686  *		*ctx* is either **struct xdp_md** for XDP programs or
4687  *		**struct sk_buff** for tc cls_act programs.
4688  *
4689  *		The *flags* argument can be a combination of one or more of the
4690  *		following values:
4691  *
4692  *		**BPF_MTU_CHK_SEGS**
4693  *			This flag will only works for *ctx* **struct sk_buff**.
4694  *			If packet context contains extra packet segment buffers
4695  *			(often knows as GSO skb), then MTU check is harder to
4696  *			check at this point, because in transmit path it is
4697  *			possible for the skb packet to get re-segmented
4698  *			(depending on net device features).  This could still be
4699  *			a MTU violation, so this flag enables performing MTU
4700  *			check against segments, with a different violation
4701  *			return code to tell it apart. Check cannot use len_diff.
4702  *
4703  *		On return *mtu_len* pointer contains the MTU value of the net
4704  *		device.  Remember the net device configured MTU is the L3 size,
4705  *		which is returned here and XDP and TC length operate at L2.
4706  *		Helper take this into account for you, but remember when using
4707  *		MTU value in your BPF-code.
4708  *
4709  *	Return
4710  *		* 0 on success, and populate MTU value in *mtu_len* pointer.
4711  *
4712  *		* < 0 if any input argument is invalid (*mtu_len* not updated)
4713  *
4714  *		MTU violations return positive values, but also populate MTU
4715  *		value in *mtu_len* pointer, as this can be needed for
4716  *		implementing PMTU handing:
4717  *
4718  *		* **BPF_MTU_CHK_RET_FRAG_NEEDED**
4719  *		* **BPF_MTU_CHK_RET_SEGS_TOOBIG**
4720  *
4721  * long bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, void *callback_ctx, u64 flags)
4722  *	Description
4723  *		For each element in **map**, call **callback_fn** function with
4724  *		**map**, **callback_ctx** and other map-specific parameters.
4725  *		The **callback_fn** should be a static function and
4726  *		the **callback_ctx** should be a pointer to the stack.
4727  *		The **flags** is used to control certain aspects of the helper.
4728  *		Currently, the **flags** must be 0.
4729  *
4730  *		The following are a list of supported map types and their
4731  *		respective expected callback signatures:
4732  *
4733  *		BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
4734  *		BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
4735  *		BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
4736  *
4737  *		long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
4738  *
4739  *		For per_cpu maps, the map_value is the value on the cpu where the
4740  *		bpf_prog is running.
4741  *
4742  *		If **callback_fn** return 0, the helper will continue to the next
4743  *		element. If return value is 1, the helper will skip the rest of
4744  *		elements and return. Other return values are not used now.
4745  *
4746  *	Return
4747  *		The number of traversed map elements for success, **-EINVAL** for
4748  *		invalid **flags**.
4749  *
4750  * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len)
4751  *	Description
4752  *		Outputs a string into the **str** buffer of size **str_size**
4753  *		based on a format string stored in a read-only map pointed by
4754  *		**fmt**.
4755  *
4756  *		Each format specifier in **fmt** corresponds to one u64 element
4757  *		in the **data** array. For strings and pointers where pointees
4758  *		are accessed, only the pointer values are stored in the *data*
4759  *		array. The *data_len* is the size of *data* in bytes.
4760  *
4761  *		Formats **%s** and **%p{i,I}{4,6}** require to read kernel
4762  *		memory. Reading kernel memory may fail due to either invalid
4763  *		address or valid address but requiring a major memory fault. If
4764  *		reading kernel memory fails, the string for **%s** will be an
4765  *		empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
4766  *		Not returning error to bpf program is consistent with what
4767  *		**bpf_trace_printk**\ () does for now.
4768  *
4769  *	Return
4770  *		The strictly positive length of the formatted string, including
4771  *		the trailing zero character. If the return value is greater than
4772  *		**str_size**, **str** contains a truncated string, guaranteed to
4773  *		be zero-terminated except when **str_size** is 0.
4774  *
4775  *		Or **-EBUSY** if the per-CPU memory copy buffer is busy.
4776  *
4777  * long bpf_sys_bpf(u32 cmd, void *attr, u32 attr_size)
4778  * 	Description
4779  * 		Execute bpf syscall with given arguments.
4780  * 	Return
4781  * 		A syscall result.
4782  *
4783  * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags)
4784  * 	Description
4785  * 		Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
4786  * 	Return
4787  * 		Returns btf_id and btf_obj_fd in lower and upper 32 bits.
4788  *
4789  * long bpf_sys_close(u32 fd)
4790  * 	Description
4791  * 		Execute close syscall for given FD.
4792  * 	Return
4793  * 		A syscall result.
4794  *
4795  * long bpf_timer_init(struct bpf_timer *timer, struct bpf_map *map, u64 flags)
4796  *	Description
4797  *		Initialize the timer.
4798  *		First 4 bits of *flags* specify clockid.
4799  *		Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
4800  *		All other bits of *flags* are reserved.
4801  *		The verifier will reject the program if *timer* is not from
4802  *		the same *map*.
4803  *	Return
4804  *		0 on success.
4805  *		**-EBUSY** if *timer* is already initialized.
4806  *		**-EINVAL** if invalid *flags* are passed.
4807  *		**-EPERM** if *timer* is in a map that doesn't have any user references.
4808  *		The user space should either hold a file descriptor to a map with timers
4809  *		or pin such map in bpffs. When map is unpinned or file descriptor is
4810  *		closed all timers in the map will be cancelled and freed.
4811  *
4812  * long bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn)
4813  *	Description
4814  *		Configure the timer to call *callback_fn* static function.
4815  *	Return
4816  *		0 on success.
4817  *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4818  *		**-EPERM** if *timer* is in a map that doesn't have any user references.
4819  *		The user space should either hold a file descriptor to a map with timers
4820  *		or pin such map in bpffs. When map is unpinned or file descriptor is
4821  *		closed all timers in the map will be cancelled and freed.
4822  *
4823  * long bpf_timer_start(struct bpf_timer *timer, u64 nsecs, u64 flags)
4824  *	Description
4825  *		Set timer expiration N nanoseconds from the current time. The
4826  *		configured callback will be invoked in soft irq context on some cpu
4827  *		and will not repeat unless another bpf_timer_start() is made.
4828  *		In such case the next invocation can migrate to a different cpu.
4829  *		Since struct bpf_timer is a field inside map element the map
4830  *		owns the timer. The bpf_timer_set_callback() will increment refcnt
4831  *		of BPF program to make sure that callback_fn code stays valid.
4832  *		When user space reference to a map reaches zero all timers
4833  *		in a map are cancelled and corresponding program's refcnts are
4834  *		decremented. This is done to make sure that Ctrl-C of a user
4835  *		process doesn't leave any timers running. If map is pinned in
4836  *		bpffs the callback_fn can re-arm itself indefinitely.
4837  *		bpf_map_update/delete_elem() helpers and user space sys_bpf commands
4838  *		cancel and free the timer in the given map element.
4839  *		The map can contain timers that invoke callback_fn-s from different
4840  *		programs. The same callback_fn can serve different timers from
4841  *		different maps if key/value layout matches across maps.
4842  *		Every bpf_timer_set_callback() can have different callback_fn.
4843  *
4844  *	Return
4845  *		0 on success.
4846  *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
4847  *		or invalid *flags* are passed.
4848  *
4849  * long bpf_timer_cancel(struct bpf_timer *timer)
4850  *	Description
4851  *		Cancel the timer and wait for callback_fn to finish if it was running.
4852  *	Return
4853  *		0 if the timer was not active.
4854  *		1 if the timer was active.
4855  *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4856  *		**-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
4857  *		own timer which would have led to a deadlock otherwise.
4858  *
4859  * u64 bpf_get_func_ip(void *ctx)
4860  * 	Description
4861  * 		Get address of the traced function (for tracing and kprobe programs).
4862  * 	Return
4863  * 		Address of the traced function.
4864  *
4865  * u64 bpf_get_attach_cookie(void *ctx)
4866  * 	Description
4867  * 		Get bpf_cookie value provided (optionally) during the program
4868  * 		attachment. It might be different for each individual
4869  * 		attachment, even if BPF program itself is the same.
4870  * 		Expects BPF program context *ctx* as a first argument.
4871  *
4872  * 		Supported for the following program types:
4873  *			- kprobe/uprobe;
4874  *			- tracepoint;
4875  *			- perf_event.
4876  * 	Return
4877  *		Value specified by user at BPF link creation/attachment time
4878  *		or 0, if it was not specified.
4879  *
4880  * long bpf_task_pt_regs(struct task_struct *task)
4881  *	Description
4882  *		Get the struct pt_regs associated with **task**.
4883  *	Return
4884  *		A pointer to struct pt_regs.
4885  */
4886 #define __BPF_FUNC_MAPPER(FN)		\
4887 	FN(unspec),			\
4888 	FN(map_lookup_elem),		\
4889 	FN(map_update_elem),		\
4890 	FN(map_delete_elem),		\
4891 	FN(probe_read),			\
4892 	FN(ktime_get_ns),		\
4893 	FN(trace_printk),		\
4894 	FN(get_prandom_u32),		\
4895 	FN(get_smp_processor_id),	\
4896 	FN(skb_store_bytes),		\
4897 	FN(l3_csum_replace),		\
4898 	FN(l4_csum_replace),		\
4899 	FN(tail_call),			\
4900 	FN(clone_redirect),		\
4901 	FN(get_current_pid_tgid),	\
4902 	FN(get_current_uid_gid),	\
4903 	FN(get_current_comm),		\
4904 	FN(get_cgroup_classid),		\
4905 	FN(skb_vlan_push),		\
4906 	FN(skb_vlan_pop),		\
4907 	FN(skb_get_tunnel_key),		\
4908 	FN(skb_set_tunnel_key),		\
4909 	FN(perf_event_read),		\
4910 	FN(redirect),			\
4911 	FN(get_route_realm),		\
4912 	FN(perf_event_output),		\
4913 	FN(skb_load_bytes),		\
4914 	FN(get_stackid),		\
4915 	FN(csum_diff),			\
4916 	FN(skb_get_tunnel_opt),		\
4917 	FN(skb_set_tunnel_opt),		\
4918 	FN(skb_change_proto),		\
4919 	FN(skb_change_type),		\
4920 	FN(skb_under_cgroup),		\
4921 	FN(get_hash_recalc),		\
4922 	FN(get_current_task),		\
4923 	FN(probe_write_user),		\
4924 	FN(current_task_under_cgroup),	\
4925 	FN(skb_change_tail),		\
4926 	FN(skb_pull_data),		\
4927 	FN(csum_update),		\
4928 	FN(set_hash_invalid),		\
4929 	FN(get_numa_node_id),		\
4930 	FN(skb_change_head),		\
4931 	FN(xdp_adjust_head),		\
4932 	FN(probe_read_str),		\
4933 	FN(get_socket_cookie),		\
4934 	FN(get_socket_uid),		\
4935 	FN(set_hash),			\
4936 	FN(setsockopt),			\
4937 	FN(skb_adjust_room),		\
4938 	FN(redirect_map),		\
4939 	FN(sk_redirect_map),		\
4940 	FN(sock_map_update),		\
4941 	FN(xdp_adjust_meta),		\
4942 	FN(perf_event_read_value),	\
4943 	FN(perf_prog_read_value),	\
4944 	FN(getsockopt),			\
4945 	FN(override_return),		\
4946 	FN(sock_ops_cb_flags_set),	\
4947 	FN(msg_redirect_map),		\
4948 	FN(msg_apply_bytes),		\
4949 	FN(msg_cork_bytes),		\
4950 	FN(msg_pull_data),		\
4951 	FN(bind),			\
4952 	FN(xdp_adjust_tail),		\
4953 	FN(skb_get_xfrm_state),		\
4954 	FN(get_stack),			\
4955 	FN(skb_load_bytes_relative),	\
4956 	FN(fib_lookup),			\
4957 	FN(sock_hash_update),		\
4958 	FN(msg_redirect_hash),		\
4959 	FN(sk_redirect_hash),		\
4960 	FN(lwt_push_encap),		\
4961 	FN(lwt_seg6_store_bytes),	\
4962 	FN(lwt_seg6_adjust_srh),	\
4963 	FN(lwt_seg6_action),		\
4964 	FN(rc_repeat),			\
4965 	FN(rc_keydown),			\
4966 	FN(skb_cgroup_id),		\
4967 	FN(get_current_cgroup_id),	\
4968 	FN(get_local_storage),		\
4969 	FN(sk_select_reuseport),	\
4970 	FN(skb_ancestor_cgroup_id),	\
4971 	FN(sk_lookup_tcp),		\
4972 	FN(sk_lookup_udp),		\
4973 	FN(sk_release),			\
4974 	FN(map_push_elem),		\
4975 	FN(map_pop_elem),		\
4976 	FN(map_peek_elem),		\
4977 	FN(msg_push_data),		\
4978 	FN(msg_pop_data),		\
4979 	FN(rc_pointer_rel),		\
4980 	FN(spin_lock),			\
4981 	FN(spin_unlock),		\
4982 	FN(sk_fullsock),		\
4983 	FN(tcp_sock),			\
4984 	FN(skb_ecn_set_ce),		\
4985 	FN(get_listener_sock),		\
4986 	FN(skc_lookup_tcp),		\
4987 	FN(tcp_check_syncookie),	\
4988 	FN(sysctl_get_name),		\
4989 	FN(sysctl_get_current_value),	\
4990 	FN(sysctl_get_new_value),	\
4991 	FN(sysctl_set_new_value),	\
4992 	FN(strtol),			\
4993 	FN(strtoul),			\
4994 	FN(sk_storage_get),		\
4995 	FN(sk_storage_delete),		\
4996 	FN(send_signal),		\
4997 	FN(tcp_gen_syncookie),		\
4998 	FN(skb_output),			\
4999 	FN(probe_read_user),		\
5000 	FN(probe_read_kernel),		\
5001 	FN(probe_read_user_str),	\
5002 	FN(probe_read_kernel_str),	\
5003 	FN(tcp_send_ack),		\
5004 	FN(send_signal_thread),		\
5005 	FN(jiffies64),			\
5006 	FN(read_branch_records),	\
5007 	FN(get_ns_current_pid_tgid),	\
5008 	FN(xdp_output),			\
5009 	FN(get_netns_cookie),		\
5010 	FN(get_current_ancestor_cgroup_id),	\
5011 	FN(sk_assign),			\
5012 	FN(ktime_get_boot_ns),		\
5013 	FN(seq_printf),			\
5014 	FN(seq_write),			\
5015 	FN(sk_cgroup_id),		\
5016 	FN(sk_ancestor_cgroup_id),	\
5017 	FN(ringbuf_output),		\
5018 	FN(ringbuf_reserve),		\
5019 	FN(ringbuf_submit),		\
5020 	FN(ringbuf_discard),		\
5021 	FN(ringbuf_query),		\
5022 	FN(csum_level),			\
5023 	FN(skc_to_tcp6_sock),		\
5024 	FN(skc_to_tcp_sock),		\
5025 	FN(skc_to_tcp_timewait_sock),	\
5026 	FN(skc_to_tcp_request_sock),	\
5027 	FN(skc_to_udp6_sock),		\
5028 	FN(get_task_stack),		\
5029 	FN(load_hdr_opt),		\
5030 	FN(store_hdr_opt),		\
5031 	FN(reserve_hdr_opt),		\
5032 	FN(inode_storage_get),		\
5033 	FN(inode_storage_delete),	\
5034 	FN(d_path),			\
5035 	FN(copy_from_user),		\
5036 	FN(snprintf_btf),		\
5037 	FN(seq_printf_btf),		\
5038 	FN(skb_cgroup_classid),		\
5039 	FN(redirect_neigh),		\
5040 	FN(per_cpu_ptr),		\
5041 	FN(this_cpu_ptr),		\
5042 	FN(redirect_peer),		\
5043 	FN(task_storage_get),		\
5044 	FN(task_storage_delete),	\
5045 	FN(get_current_task_btf),	\
5046 	FN(bprm_opts_set),		\
5047 	FN(ktime_get_coarse_ns),	\
5048 	FN(ima_inode_hash),		\
5049 	FN(sock_from_file),		\
5050 	FN(check_mtu),			\
5051 	FN(for_each_map_elem),		\
5052 	FN(snprintf),			\
5053 	FN(sys_bpf),			\
5054 	FN(btf_find_by_name_kind),	\
5055 	FN(sys_close),			\
5056 	FN(timer_init),			\
5057 	FN(timer_set_callback),		\
5058 	FN(timer_start),		\
5059 	FN(timer_cancel),		\
5060 	FN(get_func_ip),		\
5061 	FN(get_attach_cookie),		\
5062 	FN(task_pt_regs),		\
5063 	/* */
5064 
5065 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
5066  * function eBPF program intends to call
5067  */
5068 #define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
5069 enum bpf_func_id {
5070 	__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
5071 	__BPF_FUNC_MAX_ID,
5072 };
5073 #undef __BPF_ENUM_FN
5074 
5075 /* All flags used by eBPF helper functions, placed here. */
5076 
5077 /* BPF_FUNC_skb_store_bytes flags. */
5078 enum {
5079 	BPF_F_RECOMPUTE_CSUM		= (1ULL << 0),
5080 	BPF_F_INVALIDATE_HASH		= (1ULL << 1),
5081 };
5082 
5083 /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
5084  * First 4 bits are for passing the header field size.
5085  */
5086 enum {
5087 	BPF_F_HDR_FIELD_MASK		= 0xfULL,
5088 };
5089 
5090 /* BPF_FUNC_l4_csum_replace flags. */
5091 enum {
5092 	BPF_F_PSEUDO_HDR		= (1ULL << 4),
5093 	BPF_F_MARK_MANGLED_0		= (1ULL << 5),
5094 	BPF_F_MARK_ENFORCE		= (1ULL << 6),
5095 };
5096 
5097 /* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
5098 enum {
5099 	BPF_F_INGRESS			= (1ULL << 0),
5100 };
5101 
5102 /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
5103 enum {
5104 	BPF_F_TUNINFO_IPV6		= (1ULL << 0),
5105 };
5106 
5107 /* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
5108 enum {
5109 	BPF_F_SKIP_FIELD_MASK		= 0xffULL,
5110 	BPF_F_USER_STACK		= (1ULL << 8),
5111 /* flags used by BPF_FUNC_get_stackid only. */
5112 	BPF_F_FAST_STACK_CMP		= (1ULL << 9),
5113 	BPF_F_REUSE_STACKID		= (1ULL << 10),
5114 /* flags used by BPF_FUNC_get_stack only. */
5115 	BPF_F_USER_BUILD_ID		= (1ULL << 11),
5116 };
5117 
5118 /* BPF_FUNC_skb_set_tunnel_key flags. */
5119 enum {
5120 	BPF_F_ZERO_CSUM_TX		= (1ULL << 1),
5121 	BPF_F_DONT_FRAGMENT		= (1ULL << 2),
5122 	BPF_F_SEQ_NUMBER		= (1ULL << 3),
5123 };
5124 
5125 /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
5126  * BPF_FUNC_perf_event_read_value flags.
5127  */
5128 enum {
5129 	BPF_F_INDEX_MASK		= 0xffffffffULL,
5130 	BPF_F_CURRENT_CPU		= BPF_F_INDEX_MASK,
5131 /* BPF_FUNC_perf_event_output for sk_buff input context. */
5132 	BPF_F_CTXLEN_MASK		= (0xfffffULL << 32),
5133 };
5134 
5135 /* Current network namespace */
5136 enum {
5137 	BPF_F_CURRENT_NETNS		= (-1L),
5138 };
5139 
5140 /* BPF_FUNC_csum_level level values. */
5141 enum {
5142 	BPF_CSUM_LEVEL_QUERY,
5143 	BPF_CSUM_LEVEL_INC,
5144 	BPF_CSUM_LEVEL_DEC,
5145 	BPF_CSUM_LEVEL_RESET,
5146 };
5147 
5148 /* BPF_FUNC_skb_adjust_room flags. */
5149 enum {
5150 	BPF_F_ADJ_ROOM_FIXED_GSO	= (1ULL << 0),
5151 	BPF_F_ADJ_ROOM_ENCAP_L3_IPV4	= (1ULL << 1),
5152 	BPF_F_ADJ_ROOM_ENCAP_L3_IPV6	= (1ULL << 2),
5153 	BPF_F_ADJ_ROOM_ENCAP_L4_GRE	= (1ULL << 3),
5154 	BPF_F_ADJ_ROOM_ENCAP_L4_UDP	= (1ULL << 4),
5155 	BPF_F_ADJ_ROOM_NO_CSUM_RESET	= (1ULL << 5),
5156 	BPF_F_ADJ_ROOM_ENCAP_L2_ETH	= (1ULL << 6),
5157 };
5158 
5159 enum {
5160 	BPF_ADJ_ROOM_ENCAP_L2_MASK	= 0xff,
5161 	BPF_ADJ_ROOM_ENCAP_L2_SHIFT	= 56,
5162 };
5163 
5164 #define BPF_F_ADJ_ROOM_ENCAP_L2(len)	(((__u64)len & \
5165 					  BPF_ADJ_ROOM_ENCAP_L2_MASK) \
5166 					 << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
5167 
5168 /* BPF_FUNC_sysctl_get_name flags. */
5169 enum {
5170 	BPF_F_SYSCTL_BASE_NAME		= (1ULL << 0),
5171 };
5172 
5173 /* BPF_FUNC_<kernel_obj>_storage_get flags */
5174 enum {
5175 	BPF_LOCAL_STORAGE_GET_F_CREATE	= (1ULL << 0),
5176 	/* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
5177 	 * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
5178 	 */
5179 	BPF_SK_STORAGE_GET_F_CREATE  = BPF_LOCAL_STORAGE_GET_F_CREATE,
5180 };
5181 
5182 /* BPF_FUNC_read_branch_records flags. */
5183 enum {
5184 	BPF_F_GET_BRANCH_RECORDS_SIZE	= (1ULL << 0),
5185 };
5186 
5187 /* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and
5188  * BPF_FUNC_bpf_ringbuf_output flags.
5189  */
5190 enum {
5191 	BPF_RB_NO_WAKEUP		= (1ULL << 0),
5192 	BPF_RB_FORCE_WAKEUP		= (1ULL << 1),
5193 };
5194 
5195 /* BPF_FUNC_bpf_ringbuf_query flags */
5196 enum {
5197 	BPF_RB_AVAIL_DATA = 0,
5198 	BPF_RB_RING_SIZE = 1,
5199 	BPF_RB_CONS_POS = 2,
5200 	BPF_RB_PROD_POS = 3,
5201 };
5202 
5203 /* BPF ring buffer constants */
5204 enum {
5205 	BPF_RINGBUF_BUSY_BIT		= (1U << 31),
5206 	BPF_RINGBUF_DISCARD_BIT		= (1U << 30),
5207 	BPF_RINGBUF_HDR_SZ		= 8,
5208 };
5209 
5210 /* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */
5211 enum {
5212 	BPF_SK_LOOKUP_F_REPLACE		= (1ULL << 0),
5213 	BPF_SK_LOOKUP_F_NO_REUSEPORT	= (1ULL << 1),
5214 };
5215 
5216 /* Mode for BPF_FUNC_skb_adjust_room helper. */
5217 enum bpf_adj_room_mode {
5218 	BPF_ADJ_ROOM_NET,
5219 	BPF_ADJ_ROOM_MAC,
5220 };
5221 
5222 /* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
5223 enum bpf_hdr_start_off {
5224 	BPF_HDR_START_MAC,
5225 	BPF_HDR_START_NET,
5226 };
5227 
5228 /* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
5229 enum bpf_lwt_encap_mode {
5230 	BPF_LWT_ENCAP_SEG6,
5231 	BPF_LWT_ENCAP_SEG6_INLINE,
5232 	BPF_LWT_ENCAP_IP,
5233 };
5234 
5235 /* Flags for bpf_bprm_opts_set helper */
5236 enum {
5237 	BPF_F_BPRM_SECUREEXEC	= (1ULL << 0),
5238 };
5239 
5240 /* Flags for bpf_redirect_map helper */
5241 enum {
5242 	BPF_F_BROADCAST		= (1ULL << 3),
5243 	BPF_F_EXCLUDE_INGRESS	= (1ULL << 4),
5244 };
5245 
5246 #define __bpf_md_ptr(type, name)	\
5247 union {					\
5248 	type name;			\
5249 	__u64 :64;			\
5250 } __attribute__((aligned(8)))
5251 
5252 /* user accessible mirror of in-kernel sk_buff.
5253  * new fields can only be added to the end of this structure
5254  */
5255 struct __sk_buff {
5256 	__u32 len;
5257 	__u32 pkt_type;
5258 	__u32 mark;
5259 	__u32 queue_mapping;
5260 	__u32 protocol;
5261 	__u32 vlan_present;
5262 	__u32 vlan_tci;
5263 	__u32 vlan_proto;
5264 	__u32 priority;
5265 	__u32 ingress_ifindex;
5266 	__u32 ifindex;
5267 	__u32 tc_index;
5268 	__u32 cb[5];
5269 	__u32 hash;
5270 	__u32 tc_classid;
5271 	__u32 data;
5272 	__u32 data_end;
5273 	__u32 napi_id;
5274 
5275 	/* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
5276 	__u32 family;
5277 	__u32 remote_ip4;	/* Stored in network byte order */
5278 	__u32 local_ip4;	/* Stored in network byte order */
5279 	__u32 remote_ip6[4];	/* Stored in network byte order */
5280 	__u32 local_ip6[4];	/* Stored in network byte order */
5281 	__u32 remote_port;	/* Stored in network byte order */
5282 	__u32 local_port;	/* stored in host byte order */
5283 	/* ... here. */
5284 
5285 	__u32 data_meta;
5286 	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
5287 	__u64 tstamp;
5288 	__u32 wire_len;
5289 	__u32 gso_segs;
5290 	__bpf_md_ptr(struct bpf_sock *, sk);
5291 	__u32 gso_size;
5292 };
5293 
5294 struct bpf_tunnel_key {
5295 	__u32 tunnel_id;
5296 	union {
5297 		__u32 remote_ipv4;
5298 		__u32 remote_ipv6[4];
5299 	};
5300 	__u8 tunnel_tos;
5301 	__u8 tunnel_ttl;
5302 	__u16 tunnel_ext;	/* Padding, future use. */
5303 	__u32 tunnel_label;
5304 };
5305 
5306 /* user accessible mirror of in-kernel xfrm_state.
5307  * new fields can only be added to the end of this structure
5308  */
5309 struct bpf_xfrm_state {
5310 	__u32 reqid;
5311 	__u32 spi;	/* Stored in network byte order */
5312 	__u16 family;
5313 	__u16 ext;	/* Padding, future use. */
5314 	union {
5315 		__u32 remote_ipv4;	/* Stored in network byte order */
5316 		__u32 remote_ipv6[4];	/* Stored in network byte order */
5317 	};
5318 };
5319 
5320 /* Generic BPF return codes which all BPF program types may support.
5321  * The values are binary compatible with their TC_ACT_* counter-part to
5322  * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
5323  * programs.
5324  *
5325  * XDP is handled seprately, see XDP_*.
5326  */
5327 enum bpf_ret_code {
5328 	BPF_OK = 0,
5329 	/* 1 reserved */
5330 	BPF_DROP = 2,
5331 	/* 3-6 reserved */
5332 	BPF_REDIRECT = 7,
5333 	/* >127 are reserved for prog type specific return codes.
5334 	 *
5335 	 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
5336 	 *    BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
5337 	 *    changed and should be routed based on its new L3 header.
5338 	 *    (This is an L3 redirect, as opposed to L2 redirect
5339 	 *    represented by BPF_REDIRECT above).
5340 	 */
5341 	BPF_LWT_REROUTE = 128,
5342 };
5343 
5344 struct bpf_sock {
5345 	__u32 bound_dev_if;
5346 	__u32 family;
5347 	__u32 type;
5348 	__u32 protocol;
5349 	__u32 mark;
5350 	__u32 priority;
5351 	/* IP address also allows 1 and 2 bytes access */
5352 	__u32 src_ip4;
5353 	__u32 src_ip6[4];
5354 	__u32 src_port;		/* host byte order */
5355 	__be16 dst_port;	/* network byte order */
5356 	__u16 :16;		/* zero padding */
5357 	__u32 dst_ip4;
5358 	__u32 dst_ip6[4];
5359 	__u32 state;
5360 	__s32 rx_queue_mapping;
5361 };
5362 
5363 struct bpf_tcp_sock {
5364 	__u32 snd_cwnd;		/* Sending congestion window		*/
5365 	__u32 srtt_us;		/* smoothed round trip time << 3 in usecs */
5366 	__u32 rtt_min;
5367 	__u32 snd_ssthresh;	/* Slow start size threshold		*/
5368 	__u32 rcv_nxt;		/* What we want to receive next		*/
5369 	__u32 snd_nxt;		/* Next sequence we send		*/
5370 	__u32 snd_una;		/* First byte we want an ack for	*/
5371 	__u32 mss_cache;	/* Cached effective mss, not including SACKS */
5372 	__u32 ecn_flags;	/* ECN status bits.			*/
5373 	__u32 rate_delivered;	/* saved rate sample: packets delivered */
5374 	__u32 rate_interval_us;	/* saved rate sample: time elapsed */
5375 	__u32 packets_out;	/* Packets which are "in flight"	*/
5376 	__u32 retrans_out;	/* Retransmitted packets out		*/
5377 	__u32 total_retrans;	/* Total retransmits for entire connection */
5378 	__u32 segs_in;		/* RFC4898 tcpEStatsPerfSegsIn
5379 				 * total number of segments in.
5380 				 */
5381 	__u32 data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
5382 				 * total number of data segments in.
5383 				 */
5384 	__u32 segs_out;		/* RFC4898 tcpEStatsPerfSegsOut
5385 				 * The total number of segments sent.
5386 				 */
5387 	__u32 data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
5388 				 * total number of data segments sent.
5389 				 */
5390 	__u32 lost_out;		/* Lost packets			*/
5391 	__u32 sacked_out;	/* SACK'd packets			*/
5392 	__u64 bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
5393 				 * sum(delta(rcv_nxt)), or how many bytes
5394 				 * were acked.
5395 				 */
5396 	__u64 bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
5397 				 * sum(delta(snd_una)), or how many bytes
5398 				 * were acked.
5399 				 */
5400 	__u32 dsack_dups;	/* RFC4898 tcpEStatsStackDSACKDups
5401 				 * total number of DSACK blocks received
5402 				 */
5403 	__u32 delivered;	/* Total data packets delivered incl. rexmits */
5404 	__u32 delivered_ce;	/* Like the above but only ECE marked packets */
5405 	__u32 icsk_retransmits;	/* Number of unrecovered [RTO] timeouts */
5406 };
5407 
5408 struct bpf_sock_tuple {
5409 	union {
5410 		struct {
5411 			__be32 saddr;
5412 			__be32 daddr;
5413 			__be16 sport;
5414 			__be16 dport;
5415 		} ipv4;
5416 		struct {
5417 			__be32 saddr[4];
5418 			__be32 daddr[4];
5419 			__be16 sport;
5420 			__be16 dport;
5421 		} ipv6;
5422 	};
5423 };
5424 
5425 struct bpf_xdp_sock {
5426 	__u32 queue_id;
5427 };
5428 
5429 #define XDP_PACKET_HEADROOM 256
5430 
5431 /* User return codes for XDP prog type.
5432  * A valid XDP program must return one of these defined values. All other
5433  * return codes are reserved for future use. Unknown return codes will
5434  * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
5435  */
5436 enum xdp_action {
5437 	XDP_ABORTED = 0,
5438 	XDP_DROP,
5439 	XDP_PASS,
5440 	XDP_TX,
5441 	XDP_REDIRECT,
5442 };
5443 
5444 /* user accessible metadata for XDP packet hook
5445  * new fields must be added to the end of this structure
5446  */
5447 struct xdp_md {
5448 	__u32 data;
5449 	__u32 data_end;
5450 	__u32 data_meta;
5451 	/* Below access go through struct xdp_rxq_info */
5452 	__u32 ingress_ifindex; /* rxq->dev->ifindex */
5453 	__u32 rx_queue_index;  /* rxq->queue_index  */
5454 
5455 	__u32 egress_ifindex;  /* txq->dev->ifindex */
5456 };
5457 
5458 /* DEVMAP map-value layout
5459  *
5460  * The struct data-layout of map-value is a configuration interface.
5461  * New members can only be added to the end of this structure.
5462  */
5463 struct bpf_devmap_val {
5464 	__u32 ifindex;   /* device index */
5465 	union {
5466 		int   fd;  /* prog fd on map write */
5467 		__u32 id;  /* prog id on map read */
5468 	} bpf_prog;
5469 };
5470 
5471 /* CPUMAP map-value layout
5472  *
5473  * The struct data-layout of map-value is a configuration interface.
5474  * New members can only be added to the end of this structure.
5475  */
5476 struct bpf_cpumap_val {
5477 	__u32 qsize;	/* queue size to remote target CPU */
5478 	union {
5479 		int   fd;	/* prog fd on map write */
5480 		__u32 id;	/* prog id on map read */
5481 	} bpf_prog;
5482 };
5483 
5484 enum sk_action {
5485 	SK_DROP = 0,
5486 	SK_PASS,
5487 };
5488 
5489 /* user accessible metadata for SK_MSG packet hook, new fields must
5490  * be added to the end of this structure
5491  */
5492 struct sk_msg_md {
5493 	__bpf_md_ptr(void *, data);
5494 	__bpf_md_ptr(void *, data_end);
5495 
5496 	__u32 family;
5497 	__u32 remote_ip4;	/* Stored in network byte order */
5498 	__u32 local_ip4;	/* Stored in network byte order */
5499 	__u32 remote_ip6[4];	/* Stored in network byte order */
5500 	__u32 local_ip6[4];	/* Stored in network byte order */
5501 	__u32 remote_port;	/* Stored in network byte order */
5502 	__u32 local_port;	/* stored in host byte order */
5503 	__u32 size;		/* Total size of sk_msg */
5504 
5505 	__bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
5506 };
5507 
5508 struct sk_reuseport_md {
5509 	/*
5510 	 * Start of directly accessible data. It begins from
5511 	 * the tcp/udp header.
5512 	 */
5513 	__bpf_md_ptr(void *, data);
5514 	/* End of directly accessible data */
5515 	__bpf_md_ptr(void *, data_end);
5516 	/*
5517 	 * Total length of packet (starting from the tcp/udp header).
5518 	 * Note that the directly accessible bytes (data_end - data)
5519 	 * could be less than this "len".  Those bytes could be
5520 	 * indirectly read by a helper "bpf_skb_load_bytes()".
5521 	 */
5522 	__u32 len;
5523 	/*
5524 	 * Eth protocol in the mac header (network byte order). e.g.
5525 	 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
5526 	 */
5527 	__u32 eth_protocol;
5528 	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
5529 	__u32 bind_inany;	/* Is sock bound to an INANY address? */
5530 	__u32 hash;		/* A hash of the packet 4 tuples */
5531 	/* When reuse->migrating_sk is NULL, it is selecting a sk for the
5532 	 * new incoming connection request (e.g. selecting a listen sk for
5533 	 * the received SYN in the TCP case).  reuse->sk is one of the sk
5534 	 * in the reuseport group. The bpf prog can use reuse->sk to learn
5535 	 * the local listening ip/port without looking into the skb.
5536 	 *
5537 	 * When reuse->migrating_sk is not NULL, reuse->sk is closed and
5538 	 * reuse->migrating_sk is the socket that needs to be migrated
5539 	 * to another listening socket.  migrating_sk could be a fullsock
5540 	 * sk that is fully established or a reqsk that is in-the-middle
5541 	 * of 3-way handshake.
5542 	 */
5543 	__bpf_md_ptr(struct bpf_sock *, sk);
5544 	__bpf_md_ptr(struct bpf_sock *, migrating_sk);
5545 };
5546 
5547 #define BPF_TAG_SIZE	8
5548 
5549 struct bpf_prog_info {
5550 	__u32 type;
5551 	__u32 id;
5552 	__u8  tag[BPF_TAG_SIZE];
5553 	__u32 jited_prog_len;
5554 	__u32 xlated_prog_len;
5555 	__aligned_u64 jited_prog_insns;
5556 	__aligned_u64 xlated_prog_insns;
5557 	__u64 load_time;	/* ns since boottime */
5558 	__u32 created_by_uid;
5559 	__u32 nr_map_ids;
5560 	__aligned_u64 map_ids;
5561 	char name[BPF_OBJ_NAME_LEN];
5562 	__u32 ifindex;
5563 	__u32 gpl_compatible:1;
5564 	__u32 :31; /* alignment pad */
5565 	__u64 netns_dev;
5566 	__u64 netns_ino;
5567 	__u32 nr_jited_ksyms;
5568 	__u32 nr_jited_func_lens;
5569 	__aligned_u64 jited_ksyms;
5570 	__aligned_u64 jited_func_lens;
5571 	__u32 btf_id;
5572 	__u32 func_info_rec_size;
5573 	__aligned_u64 func_info;
5574 	__u32 nr_func_info;
5575 	__u32 nr_line_info;
5576 	__aligned_u64 line_info;
5577 	__aligned_u64 jited_line_info;
5578 	__u32 nr_jited_line_info;
5579 	__u32 line_info_rec_size;
5580 	__u32 jited_line_info_rec_size;
5581 	__u32 nr_prog_tags;
5582 	__aligned_u64 prog_tags;
5583 	__u64 run_time_ns;
5584 	__u64 run_cnt;
5585 	__u64 recursion_misses;
5586 } __attribute__((aligned(8)));
5587 
5588 struct bpf_map_info {
5589 	__u32 type;
5590 	__u32 id;
5591 	__u32 key_size;
5592 	__u32 value_size;
5593 	__u32 max_entries;
5594 	__u32 map_flags;
5595 	char  name[BPF_OBJ_NAME_LEN];
5596 	__u32 ifindex;
5597 	__u32 btf_vmlinux_value_type_id;
5598 	__u64 netns_dev;
5599 	__u64 netns_ino;
5600 	__u32 btf_id;
5601 	__u32 btf_key_type_id;
5602 	__u32 btf_value_type_id;
5603 } __attribute__((aligned(8)));
5604 
5605 struct bpf_btf_info {
5606 	__aligned_u64 btf;
5607 	__u32 btf_size;
5608 	__u32 id;
5609 	__aligned_u64 name;
5610 	__u32 name_len;
5611 	__u32 kernel_btf;
5612 } __attribute__((aligned(8)));
5613 
5614 struct bpf_link_info {
5615 	__u32 type;
5616 	__u32 id;
5617 	__u32 prog_id;
5618 	union {
5619 		struct {
5620 			__aligned_u64 tp_name; /* in/out: tp_name buffer ptr */
5621 			__u32 tp_name_len;     /* in/out: tp_name buffer len */
5622 		} raw_tracepoint;
5623 		struct {
5624 			__u32 attach_type;
5625 			__u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */
5626 			__u32 target_btf_id; /* BTF type id inside the object */
5627 		} tracing;
5628 		struct {
5629 			__u64 cgroup_id;
5630 			__u32 attach_type;
5631 		} cgroup;
5632 		struct {
5633 			__aligned_u64 target_name; /* in/out: target_name buffer ptr */
5634 			__u32 target_name_len;	   /* in/out: target_name buffer len */
5635 			union {
5636 				struct {
5637 					__u32 map_id;
5638 				} map;
5639 			};
5640 		} iter;
5641 		struct  {
5642 			__u32 netns_ino;
5643 			__u32 attach_type;
5644 		} netns;
5645 		struct {
5646 			__u32 ifindex;
5647 		} xdp;
5648 	};
5649 } __attribute__((aligned(8)));
5650 
5651 /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
5652  * by user and intended to be used by socket (e.g. to bind to, depends on
5653  * attach type).
5654  */
5655 struct bpf_sock_addr {
5656 	__u32 user_family;	/* Allows 4-byte read, but no write. */
5657 	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.
5658 				 * Stored in network byte order.
5659 				 */
5660 	__u32 user_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.
5661 				 * Stored in network byte order.
5662 				 */
5663 	__u32 user_port;	/* Allows 1,2,4-byte read and 4-byte write.
5664 				 * Stored in network byte order
5665 				 */
5666 	__u32 family;		/* Allows 4-byte read, but no write */
5667 	__u32 type;		/* Allows 4-byte read, but no write */
5668 	__u32 protocol;		/* Allows 4-byte read, but no write */
5669 	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read and 4-byte write.
5670 				 * Stored in network byte order.
5671 				 */
5672 	__u32 msg_src_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.
5673 				 * Stored in network byte order.
5674 				 */
5675 	__bpf_md_ptr(struct bpf_sock *, sk);
5676 };
5677 
5678 /* User bpf_sock_ops struct to access socket values and specify request ops
5679  * and their replies.
5680  * Some of this fields are in network (bigendian) byte order and may need
5681  * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
5682  * New fields can only be added at the end of this structure
5683  */
5684 struct bpf_sock_ops {
5685 	__u32 op;
5686 	union {
5687 		__u32 args[4];		/* Optionally passed to bpf program */
5688 		__u32 reply;		/* Returned by bpf program	    */
5689 		__u32 replylong[4];	/* Optionally returned by bpf prog  */
5690 	};
5691 	__u32 family;
5692 	__u32 remote_ip4;	/* Stored in network byte order */
5693 	__u32 local_ip4;	/* Stored in network byte order */
5694 	__u32 remote_ip6[4];	/* Stored in network byte order */
5695 	__u32 local_ip6[4];	/* Stored in network byte order */
5696 	__u32 remote_port;	/* Stored in network byte order */
5697 	__u32 local_port;	/* stored in host byte order */
5698 	__u32 is_fullsock;	/* Some TCP fields are only valid if
5699 				 * there is a full socket. If not, the
5700 				 * fields read as zero.
5701 				 */
5702 	__u32 snd_cwnd;
5703 	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
5704 	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
5705 	__u32 state;
5706 	__u32 rtt_min;
5707 	__u32 snd_ssthresh;
5708 	__u32 rcv_nxt;
5709 	__u32 snd_nxt;
5710 	__u32 snd_una;
5711 	__u32 mss_cache;
5712 	__u32 ecn_flags;
5713 	__u32 rate_delivered;
5714 	__u32 rate_interval_us;
5715 	__u32 packets_out;
5716 	__u32 retrans_out;
5717 	__u32 total_retrans;
5718 	__u32 segs_in;
5719 	__u32 data_segs_in;
5720 	__u32 segs_out;
5721 	__u32 data_segs_out;
5722 	__u32 lost_out;
5723 	__u32 sacked_out;
5724 	__u32 sk_txhash;
5725 	__u64 bytes_received;
5726 	__u64 bytes_acked;
5727 	__bpf_md_ptr(struct bpf_sock *, sk);
5728 	/* [skb_data, skb_data_end) covers the whole TCP header.
5729 	 *
5730 	 * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
5731 	 * BPF_SOCK_OPS_HDR_OPT_LEN_CB:   Not useful because the
5732 	 *                                header has not been written.
5733 	 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
5734 	 *				  been written so far.
5735 	 * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:  The SYNACK that concludes
5736 	 *					the 3WHS.
5737 	 * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
5738 	 *					the 3WHS.
5739 	 *
5740 	 * bpf_load_hdr_opt() can also be used to read a particular option.
5741 	 */
5742 	__bpf_md_ptr(void *, skb_data);
5743 	__bpf_md_ptr(void *, skb_data_end);
5744 	__u32 skb_len;		/* The total length of a packet.
5745 				 * It includes the header, options,
5746 				 * and payload.
5747 				 */
5748 	__u32 skb_tcp_flags;	/* tcp_flags of the header.  It provides
5749 				 * an easy way to check for tcp_flags
5750 				 * without parsing skb_data.
5751 				 *
5752 				 * In particular, the skb_tcp_flags
5753 				 * will still be available in
5754 				 * BPF_SOCK_OPS_HDR_OPT_LEN even though
5755 				 * the outgoing header has not
5756 				 * been written yet.
5757 				 */
5758 };
5759 
5760 /* Definitions for bpf_sock_ops_cb_flags */
5761 enum {
5762 	BPF_SOCK_OPS_RTO_CB_FLAG	= (1<<0),
5763 	BPF_SOCK_OPS_RETRANS_CB_FLAG	= (1<<1),
5764 	BPF_SOCK_OPS_STATE_CB_FLAG	= (1<<2),
5765 	BPF_SOCK_OPS_RTT_CB_FLAG	= (1<<3),
5766 	/* Call bpf for all received TCP headers.  The bpf prog will be
5767 	 * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5768 	 *
5769 	 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5770 	 * for the header option related helpers that will be useful
5771 	 * to the bpf programs.
5772 	 *
5773 	 * It could be used at the client/active side (i.e. connect() side)
5774 	 * when the server told it that the server was in syncookie
5775 	 * mode and required the active side to resend the bpf-written
5776 	 * options.  The active side can keep writing the bpf-options until
5777 	 * it received a valid packet from the server side to confirm
5778 	 * the earlier packet (and options) has been received.  The later
5779 	 * example patch is using it like this at the active side when the
5780 	 * server is in syncookie mode.
5781 	 *
5782 	 * The bpf prog will usually turn this off in the common cases.
5783 	 */
5784 	BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG	= (1<<4),
5785 	/* Call bpf when kernel has received a header option that
5786 	 * the kernel cannot handle.  The bpf prog will be called under
5787 	 * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
5788 	 *
5789 	 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5790 	 * for the header option related helpers that will be useful
5791 	 * to the bpf programs.
5792 	 */
5793 	BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5),
5794 	/* Call bpf when the kernel is writing header options for the
5795 	 * outgoing packet.  The bpf prog will first be called
5796 	 * to reserve space in a skb under
5797 	 * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB.  Then
5798 	 * the bpf prog will be called to write the header option(s)
5799 	 * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5800 	 *
5801 	 * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
5802 	 * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
5803 	 * related helpers that will be useful to the bpf programs.
5804 	 *
5805 	 * The kernel gets its chance to reserve space and write
5806 	 * options first before the BPF program does.
5807 	 */
5808 	BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
5809 /* Mask of all currently supported cb flags */
5810 	BPF_SOCK_OPS_ALL_CB_FLAGS       = 0x7F,
5811 };
5812 
5813 /* List of known BPF sock_ops operators.
5814  * New entries can only be added at the end
5815  */
5816 enum {
5817 	BPF_SOCK_OPS_VOID,
5818 	BPF_SOCK_OPS_TIMEOUT_INIT,	/* Should return SYN-RTO value to use or
5819 					 * -1 if default value should be used
5820 					 */
5821 	BPF_SOCK_OPS_RWND_INIT,		/* Should return initial advertized
5822 					 * window (in packets) or -1 if default
5823 					 * value should be used
5824 					 */
5825 	BPF_SOCK_OPS_TCP_CONNECT_CB,	/* Calls BPF program right before an
5826 					 * active connection is initialized
5827 					 */
5828 	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,	/* Calls BPF program when an
5829 						 * active connection is
5830 						 * established
5831 						 */
5832 	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,	/* Calls BPF program when a
5833 						 * passive connection is
5834 						 * established
5835 						 */
5836 	BPF_SOCK_OPS_NEEDS_ECN,		/* If connection's congestion control
5837 					 * needs ECN
5838 					 */
5839 	BPF_SOCK_OPS_BASE_RTT,		/* Get base RTT. The correct value is
5840 					 * based on the path and may be
5841 					 * dependent on the congestion control
5842 					 * algorithm. In general it indicates
5843 					 * a congestion threshold. RTTs above
5844 					 * this indicate congestion
5845 					 */
5846 	BPF_SOCK_OPS_RTO_CB,		/* Called when an RTO has triggered.
5847 					 * Arg1: value of icsk_retransmits
5848 					 * Arg2: value of icsk_rto
5849 					 * Arg3: whether RTO has expired
5850 					 */
5851 	BPF_SOCK_OPS_RETRANS_CB,	/* Called when skb is retransmitted.
5852 					 * Arg1: sequence number of 1st byte
5853 					 * Arg2: # segments
5854 					 * Arg3: return value of
5855 					 *       tcp_transmit_skb (0 => success)
5856 					 */
5857 	BPF_SOCK_OPS_STATE_CB,		/* Called when TCP changes state.
5858 					 * Arg1: old_state
5859 					 * Arg2: new_state
5860 					 */
5861 	BPF_SOCK_OPS_TCP_LISTEN_CB,	/* Called on listen(2), right after
5862 					 * socket transition to LISTEN state.
5863 					 */
5864 	BPF_SOCK_OPS_RTT_CB,		/* Called on every RTT.
5865 					 */
5866 	BPF_SOCK_OPS_PARSE_HDR_OPT_CB,	/* Parse the header option.
5867 					 * It will be called to handle
5868 					 * the packets received at
5869 					 * an already established
5870 					 * connection.
5871 					 *
5872 					 * sock_ops->skb_data:
5873 					 * Referring to the received skb.
5874 					 * It covers the TCP header only.
5875 					 *
5876 					 * bpf_load_hdr_opt() can also
5877 					 * be used to search for a
5878 					 * particular option.
5879 					 */
5880 	BPF_SOCK_OPS_HDR_OPT_LEN_CB,	/* Reserve space for writing the
5881 					 * header option later in
5882 					 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5883 					 * Arg1: bool want_cookie. (in
5884 					 *       writing SYNACK only)
5885 					 *
5886 					 * sock_ops->skb_data:
5887 					 * Not available because no header has
5888 					 * been	written yet.
5889 					 *
5890 					 * sock_ops->skb_tcp_flags:
5891 					 * The tcp_flags of the
5892 					 * outgoing skb. (e.g. SYN, ACK, FIN).
5893 					 *
5894 					 * bpf_reserve_hdr_opt() should
5895 					 * be used to reserve space.
5896 					 */
5897 	BPF_SOCK_OPS_WRITE_HDR_OPT_CB,	/* Write the header options
5898 					 * Arg1: bool want_cookie. (in
5899 					 *       writing SYNACK only)
5900 					 *
5901 					 * sock_ops->skb_data:
5902 					 * Referring to the outgoing skb.
5903 					 * It covers the TCP header
5904 					 * that has already been written
5905 					 * by the kernel and the
5906 					 * earlier bpf-progs.
5907 					 *
5908 					 * sock_ops->skb_tcp_flags:
5909 					 * The tcp_flags of the outgoing
5910 					 * skb. (e.g. SYN, ACK, FIN).
5911 					 *
5912 					 * bpf_store_hdr_opt() should
5913 					 * be used to write the
5914 					 * option.
5915 					 *
5916 					 * bpf_load_hdr_opt() can also
5917 					 * be used to search for a
5918 					 * particular option that
5919 					 * has already been written
5920 					 * by the kernel or the
5921 					 * earlier bpf-progs.
5922 					 */
5923 };
5924 
5925 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
5926  * changes between the TCP and BPF versions. Ideally this should never happen.
5927  * If it does, we need to add code to convert them before calling
5928  * the BPF sock_ops function.
5929  */
5930 enum {
5931 	BPF_TCP_ESTABLISHED = 1,
5932 	BPF_TCP_SYN_SENT,
5933 	BPF_TCP_SYN_RECV,
5934 	BPF_TCP_FIN_WAIT1,
5935 	BPF_TCP_FIN_WAIT2,
5936 	BPF_TCP_TIME_WAIT,
5937 	BPF_TCP_CLOSE,
5938 	BPF_TCP_CLOSE_WAIT,
5939 	BPF_TCP_LAST_ACK,
5940 	BPF_TCP_LISTEN,
5941 	BPF_TCP_CLOSING,	/* Now a valid state */
5942 	BPF_TCP_NEW_SYN_RECV,
5943 
5944 	BPF_TCP_MAX_STATES	/* Leave at the end! */
5945 };
5946 
5947 enum {
5948 	TCP_BPF_IW		= 1001,	/* Set TCP initial congestion window */
5949 	TCP_BPF_SNDCWND_CLAMP	= 1002,	/* Set sndcwnd_clamp */
5950 	TCP_BPF_DELACK_MAX	= 1003, /* Max delay ack in usecs */
5951 	TCP_BPF_RTO_MIN		= 1004, /* Min delay ack in usecs */
5952 	/* Copy the SYN pkt to optval
5953 	 *
5954 	 * BPF_PROG_TYPE_SOCK_OPS only.  It is similar to the
5955 	 * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
5956 	 * to only getting from the saved_syn.  It can either get the
5957 	 * syn packet from:
5958 	 *
5959 	 * 1. the just-received SYN packet (only available when writing the
5960 	 *    SYNACK).  It will be useful when it is not necessary to
5961 	 *    save the SYN packet for latter use.  It is also the only way
5962 	 *    to get the SYN during syncookie mode because the syn
5963 	 *    packet cannot be saved during syncookie.
5964 	 *
5965 	 * OR
5966 	 *
5967 	 * 2. the earlier saved syn which was done by
5968 	 *    bpf_setsockopt(TCP_SAVE_SYN).
5969 	 *
5970 	 * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
5971 	 * SYN packet is obtained.
5972 	 *
5973 	 * If the bpf-prog does not need the IP[46] header,  the
5974 	 * bpf-prog can avoid parsing the IP header by using
5975 	 * TCP_BPF_SYN.  Otherwise, the bpf-prog can get both
5976 	 * IP[46] and TCP header by using TCP_BPF_SYN_IP.
5977 	 *
5978 	 *      >0: Total number of bytes copied
5979 	 * -ENOSPC: Not enough space in optval. Only optlen number of
5980 	 *          bytes is copied.
5981 	 * -ENOENT: The SYN skb is not available now and the earlier SYN pkt
5982 	 *	    is not saved by setsockopt(TCP_SAVE_SYN).
5983 	 */
5984 	TCP_BPF_SYN		= 1005, /* Copy the TCP header */
5985 	TCP_BPF_SYN_IP		= 1006, /* Copy the IP[46] and TCP header */
5986 	TCP_BPF_SYN_MAC         = 1007, /* Copy the MAC, IP[46], and TCP header */
5987 };
5988 
5989 enum {
5990 	BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0),
5991 };
5992 
5993 /* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and
5994  * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5995  */
5996 enum {
5997 	BPF_WRITE_HDR_TCP_CURRENT_MSS = 1,	/* Kernel is finding the
5998 						 * total option spaces
5999 						 * required for an established
6000 						 * sk in order to calculate the
6001 						 * MSS.  No skb is actually
6002 						 * sent.
6003 						 */
6004 	BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2,	/* Kernel is in syncookie mode
6005 						 * when sending a SYN.
6006 						 */
6007 };
6008 
6009 struct bpf_perf_event_value {
6010 	__u64 counter;
6011 	__u64 enabled;
6012 	__u64 running;
6013 };
6014 
6015 enum {
6016 	BPF_DEVCG_ACC_MKNOD	= (1ULL << 0),
6017 	BPF_DEVCG_ACC_READ	= (1ULL << 1),
6018 	BPF_DEVCG_ACC_WRITE	= (1ULL << 2),
6019 };
6020 
6021 enum {
6022 	BPF_DEVCG_DEV_BLOCK	= (1ULL << 0),
6023 	BPF_DEVCG_DEV_CHAR	= (1ULL << 1),
6024 };
6025 
6026 struct bpf_cgroup_dev_ctx {
6027 	/* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
6028 	__u32 access_type;
6029 	__u32 major;
6030 	__u32 minor;
6031 };
6032 
6033 struct bpf_raw_tracepoint_args {
6034 	__u64 args[0];
6035 };
6036 
6037 /* DIRECT:  Skip the FIB rules and go to FIB table associated with device
6038  * OUTPUT:  Do lookup from egress perspective; default is ingress
6039  */
6040 enum {
6041 	BPF_FIB_LOOKUP_DIRECT  = (1U << 0),
6042 	BPF_FIB_LOOKUP_OUTPUT  = (1U << 1),
6043 };
6044 
6045 enum {
6046 	BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
6047 	BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
6048 	BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
6049 	BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
6050 	BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
6051 	BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
6052 	BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
6053 	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
6054 	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6055 };
6056 
6057 struct bpf_fib_lookup {
6058 	/* input:  network family for lookup (AF_INET, AF_INET6)
6059 	 * output: network family of egress nexthop
6060 	 */
6061 	__u8	family;
6062 
6063 	/* set if lookup is to consider L4 data - e.g., FIB rules */
6064 	__u8	l4_protocol;
6065 	__be16	sport;
6066 	__be16	dport;
6067 
6068 	union {	/* used for MTU check */
6069 		/* input to lookup */
6070 		__u16	tot_len; /* L3 length from network hdr (iph->tot_len) */
6071 
6072 		/* output: MTU value */
6073 		__u16	mtu_result;
6074 	};
6075 	/* input: L3 device index for lookup
6076 	 * output: device index from FIB lookup
6077 	 */
6078 	__u32	ifindex;
6079 
6080 	union {
6081 		/* inputs to lookup */
6082 		__u8	tos;		/* AF_INET  */
6083 		__be32	flowinfo;	/* AF_INET6, flow_label + priority */
6084 
6085 		/* output: metric of fib result (IPv4/IPv6 only) */
6086 		__u32	rt_metric;
6087 	};
6088 
6089 	union {
6090 		__be32		ipv4_src;
6091 		__u32		ipv6_src[4];  /* in6_addr; network order */
6092 	};
6093 
6094 	/* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
6095 	 * network header. output: bpf_fib_lookup sets to gateway address
6096 	 * if FIB lookup returns gateway route
6097 	 */
6098 	union {
6099 		__be32		ipv4_dst;
6100 		__u32		ipv6_dst[4];  /* in6_addr; network order */
6101 	};
6102 
6103 	/* output */
6104 	__be16	h_vlan_proto;
6105 	__be16	h_vlan_TCI;
6106 	__u8	smac[6];     /* ETH_ALEN */
6107 	__u8	dmac[6];     /* ETH_ALEN */
6108 };
6109 
6110 struct bpf_redir_neigh {
6111 	/* network family for lookup (AF_INET, AF_INET6) */
6112 	__u32 nh_family;
6113 	/* network address of nexthop; skips fib lookup to find gateway */
6114 	union {
6115 		__be32		ipv4_nh;
6116 		__u32		ipv6_nh[4];  /* in6_addr; network order */
6117 	};
6118 };
6119 
6120 /* bpf_check_mtu flags*/
6121 enum  bpf_check_mtu_flags {
6122 	BPF_MTU_CHK_SEGS  = (1U << 0),
6123 };
6124 
6125 enum bpf_check_mtu_ret {
6126 	BPF_MTU_CHK_RET_SUCCESS,      /* check and lookup successful */
6127 	BPF_MTU_CHK_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6128 	BPF_MTU_CHK_RET_SEGS_TOOBIG,  /* GSO re-segmentation needed to fwd */
6129 };
6130 
6131 enum bpf_task_fd_type {
6132 	BPF_FD_TYPE_RAW_TRACEPOINT,	/* tp name */
6133 	BPF_FD_TYPE_TRACEPOINT,		/* tp name */
6134 	BPF_FD_TYPE_KPROBE,		/* (symbol + offset) or addr */
6135 	BPF_FD_TYPE_KRETPROBE,		/* (symbol + offset) or addr */
6136 	BPF_FD_TYPE_UPROBE,		/* filename + offset */
6137 	BPF_FD_TYPE_URETPROBE,		/* filename + offset */
6138 };
6139 
6140 enum {
6141 	BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG		= (1U << 0),
6142 	BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL		= (1U << 1),
6143 	BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP		= (1U << 2),
6144 };
6145 
6146 struct bpf_flow_keys {
6147 	__u16	nhoff;
6148 	__u16	thoff;
6149 	__u16	addr_proto;			/* ETH_P_* of valid addrs */
6150 	__u8	is_frag;
6151 	__u8	is_first_frag;
6152 	__u8	is_encap;
6153 	__u8	ip_proto;
6154 	__be16	n_proto;
6155 	__be16	sport;
6156 	__be16	dport;
6157 	union {
6158 		struct {
6159 			__be32	ipv4_src;
6160 			__be32	ipv4_dst;
6161 		};
6162 		struct {
6163 			__u32	ipv6_src[4];	/* in6_addr; network order */
6164 			__u32	ipv6_dst[4];	/* in6_addr; network order */
6165 		};
6166 	};
6167 	__u32	flags;
6168 	__be32	flow_label;
6169 };
6170 
6171 struct bpf_func_info {
6172 	__u32	insn_off;
6173 	__u32	type_id;
6174 };
6175 
6176 #define BPF_LINE_INFO_LINE_NUM(line_col)	((line_col) >> 10)
6177 #define BPF_LINE_INFO_LINE_COL(line_col)	((line_col) & 0x3ff)
6178 
6179 struct bpf_line_info {
6180 	__u32	insn_off;
6181 	__u32	file_name_off;
6182 	__u32	line_off;
6183 	__u32	line_col;
6184 };
6185 
6186 struct bpf_spin_lock {
6187 	__u32	val;
6188 };
6189 
6190 struct bpf_timer {
6191 	__u64 :64;
6192 	__u64 :64;
6193 } __attribute__((aligned(8)));
6194 
6195 struct bpf_sysctl {
6196 	__u32	write;		/* Sysctl is being read (= 0) or written (= 1).
6197 				 * Allows 1,2,4-byte read, but no write.
6198 				 */
6199 	__u32	file_pos;	/* Sysctl file position to read from, write to.
6200 				 * Allows 1,2,4-byte read an 4-byte write.
6201 				 */
6202 };
6203 
6204 struct bpf_sockopt {
6205 	__bpf_md_ptr(struct bpf_sock *, sk);
6206 	__bpf_md_ptr(void *, optval);
6207 	__bpf_md_ptr(void *, optval_end);
6208 
6209 	__s32	level;
6210 	__s32	optname;
6211 	__s32	optlen;
6212 	__s32	retval;
6213 };
6214 
6215 struct bpf_pidns_info {
6216 	__u32 pid;
6217 	__u32 tgid;
6218 };
6219 
6220 /* User accessible data for SK_LOOKUP programs. Add new fields at the end. */
6221 struct bpf_sk_lookup {
6222 	union {
6223 		__bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
6224 		__u64 cookie; /* Non-zero if socket was selected in PROG_TEST_RUN */
6225 	};
6226 
6227 	__u32 family;		/* Protocol family (AF_INET, AF_INET6) */
6228 	__u32 protocol;		/* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */
6229 	__u32 remote_ip4;	/* Network byte order */
6230 	__u32 remote_ip6[4];	/* Network byte order */
6231 	__u32 remote_port;	/* Network byte order */
6232 	__u32 local_ip4;	/* Network byte order */
6233 	__u32 local_ip6[4];	/* Network byte order */
6234 	__u32 local_port;	/* Host byte order */
6235 };
6236 
6237 /*
6238  * struct btf_ptr is used for typed pointer representation; the
6239  * type id is used to render the pointer data as the appropriate type
6240  * via the bpf_snprintf_btf() helper described above.  A flags field -
6241  * potentially to specify additional details about the BTF pointer
6242  * (rather than its mode of display) - is included for future use.
6243  * Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately.
6244  */
6245 struct btf_ptr {
6246 	void *ptr;
6247 	__u32 type_id;
6248 	__u32 flags;		/* BTF ptr flags; unused at present. */
6249 };
6250 
6251 /*
6252  * Flags to control bpf_snprintf_btf() behaviour.
6253  *     - BTF_F_COMPACT: no formatting around type information
6254  *     - BTF_F_NONAME: no struct/union member names/types
6255  *     - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
6256  *       equivalent to %px.
6257  *     - BTF_F_ZERO: show zero-valued struct/union members; they
6258  *       are not displayed by default
6259  */
6260 enum {
6261 	BTF_F_COMPACT	=	(1ULL << 0),
6262 	BTF_F_NONAME	=	(1ULL << 1),
6263 	BTF_F_PTR_RAW	=	(1ULL << 2),
6264 	BTF_F_ZERO	=	(1ULL << 3),
6265 };
6266 
6267 #endif /* _UAPI__LINUX_BPF_H__ */
6268