1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /* Copyright (c) 2021 Facebook */
3 #ifndef __SKEL_INTERNAL_H
4 #define __SKEL_INTERNAL_H
5
6 #ifdef __KERNEL__
7 #include <linux/fdtable.h>
8 #include <linux/mm.h>
9 #include <linux/mman.h>
10 #include <linux/slab.h>
11 #include <linux/bpf.h>
12 #else
13 #include <unistd.h>
14 #include <sys/syscall.h>
15 #include <sys/mman.h>
16 #include <stdlib.h>
17 #include "bpf.h"
18 #endif
19
20 #ifndef __NR_bpf
21 # if defined(__mips__) && defined(_ABIO32)
22 # define __NR_bpf 4355
23 # elif defined(__mips__) && defined(_ABIN32)
24 # define __NR_bpf 6319
25 # elif defined(__mips__) && defined(_ABI64)
26 # define __NR_bpf 5315
27 # endif
28 #endif
29
30 /* This file is a base header for auto-generated *.lskel.h files.
31 * Its contents will change and may become part of auto-generation in the future.
32 *
33 * The layout of bpf_[map|prog]_desc and bpf_loader_ctx is feature dependent
34 * and will change from one version of libbpf to another and features
35 * requested during loader program generation.
36 */
37 struct bpf_map_desc {
38 /* output of the loader prog */
39 int map_fd;
40 /* input for the loader prog */
41 __u32 max_entries;
42 __aligned_u64 initial_value;
43 };
44 struct bpf_prog_desc {
45 int prog_fd;
46 };
47
48 enum {
49 BPF_SKEL_KERNEL = (1ULL << 0),
50 };
51
52 struct bpf_loader_ctx {
53 __u32 sz;
54 __u32 flags;
55 __u32 log_level;
56 __u32 log_size;
57 __u64 log_buf;
58 };
59
60 struct bpf_load_and_run_opts {
61 struct bpf_loader_ctx *ctx;
62 const void *data;
63 const void *insns;
64 __u32 data_sz;
65 __u32 insns_sz;
66 const char *errstr;
67 };
68
69 long kern_sys_bpf(__u32 cmd, void *attr, __u32 attr_size);
70
skel_sys_bpf(enum bpf_cmd cmd,union bpf_attr * attr,unsigned int size)71 static inline int skel_sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
72 unsigned int size)
73 {
74 #ifdef __KERNEL__
75 return kern_sys_bpf(cmd, attr, size);
76 #else
77 return syscall(__NR_bpf, cmd, attr, size);
78 #endif
79 }
80
81 #ifdef __KERNEL__
close(int fd)82 static inline int close(int fd)
83 {
84 return close_fd(fd);
85 }
86
skel_alloc(size_t size)87 static inline void *skel_alloc(size_t size)
88 {
89 struct bpf_loader_ctx *ctx = kzalloc(size, GFP_KERNEL);
90
91 if (!ctx)
92 return NULL;
93 ctx->flags |= BPF_SKEL_KERNEL;
94 return ctx;
95 }
96
skel_free(const void * p)97 static inline void skel_free(const void *p)
98 {
99 kfree(p);
100 }
101
102 /* skel->bss/rodata maps are populated the following way:
103 *
104 * For kernel use:
105 * skel_prep_map_data() allocates kernel memory that kernel module can directly access.
106 * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
107 * The loader program will perform probe_read_kernel() from maps.rodata.initial_value.
108 * skel_finalize_map_data() sets skel->rodata to point to actual value in a bpf map and
109 * does maps.rodata.initial_value = ~0ULL to signal skel_free_map_data() that kvfree
110 * is not nessary.
111 *
112 * For user space:
113 * skel_prep_map_data() mmaps anon memory into skel->rodata that can be accessed directly.
114 * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
115 * The loader program will perform copy_from_user() from maps.rodata.initial_value.
116 * skel_finalize_map_data() remaps bpf array map value from the kernel memory into
117 * skel->rodata address.
118 *
119 * The "bpftool gen skeleton -L" command generates lskel.h that is suitable for
120 * both kernel and user space. The generated loader program does
121 * either bpf_probe_read_kernel() or bpf_copy_from_user() from initial_value
122 * depending on bpf_loader_ctx->flags.
123 */
skel_free_map_data(void * p,__u64 addr,size_t sz)124 static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
125 {
126 if (addr != ~0ULL)
127 kvfree(p);
128 /* When addr == ~0ULL the 'p' points to
129 * ((struct bpf_array *)map)->value. See skel_finalize_map_data.
130 */
131 }
132
skel_prep_map_data(const void * val,size_t mmap_sz,size_t val_sz)133 static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
134 {
135 void *addr;
136
137 addr = kvmalloc(val_sz, GFP_KERNEL);
138 if (!addr)
139 return NULL;
140 memcpy(addr, val, val_sz);
141 return addr;
142 }
143
skel_finalize_map_data(__u64 * init_val,size_t mmap_sz,int flags,int fd)144 static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
145 {
146 struct bpf_map *map;
147 void *addr = NULL;
148
149 kvfree((void *) (long) *init_val);
150 *init_val = ~0ULL;
151
152 /* At this point bpf_load_and_run() finished without error and
153 * 'fd' is a valid bpf map FD. All sanity checks below should succeed.
154 */
155 map = bpf_map_get(fd);
156 if (IS_ERR(map))
157 return NULL;
158 if (map->map_type != BPF_MAP_TYPE_ARRAY)
159 goto out;
160 addr = ((struct bpf_array *)map)->value;
161 /* the addr stays valid, since FD is not closed */
162 out:
163 bpf_map_put(map);
164 return addr;
165 }
166
167 #else
168
skel_alloc(size_t size)169 static inline void *skel_alloc(size_t size)
170 {
171 return calloc(1, size);
172 }
173
skel_free(void * p)174 static inline void skel_free(void *p)
175 {
176 free(p);
177 }
178
skel_free_map_data(void * p,__u64 addr,size_t sz)179 static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
180 {
181 munmap(p, sz);
182 }
183
skel_prep_map_data(const void * val,size_t mmap_sz,size_t val_sz)184 static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
185 {
186 void *addr;
187
188 addr = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
189 MAP_SHARED | MAP_ANONYMOUS, -1, 0);
190 if (addr == (void *) -1)
191 return NULL;
192 memcpy(addr, val, val_sz);
193 return addr;
194 }
195
skel_finalize_map_data(__u64 * init_val,size_t mmap_sz,int flags,int fd)196 static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
197 {
198 void *addr;
199
200 addr = mmap((void *) (long) *init_val, mmap_sz, flags, MAP_SHARED | MAP_FIXED, fd, 0);
201 if (addr == (void *) -1)
202 return NULL;
203 return addr;
204 }
205 #endif
206
skel_closenz(int fd)207 static inline int skel_closenz(int fd)
208 {
209 if (fd > 0)
210 return close(fd);
211 return -EINVAL;
212 }
213
214 #ifndef offsetofend
215 #define offsetofend(TYPE, MEMBER) \
216 (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
217 #endif
218
skel_map_create(enum bpf_map_type map_type,const char * map_name,__u32 key_size,__u32 value_size,__u32 max_entries)219 static inline int skel_map_create(enum bpf_map_type map_type,
220 const char *map_name,
221 __u32 key_size,
222 __u32 value_size,
223 __u32 max_entries)
224 {
225 const size_t attr_sz = offsetofend(union bpf_attr, map_extra);
226 union bpf_attr attr;
227
228 memset(&attr, 0, attr_sz);
229
230 attr.map_type = map_type;
231 strncpy(attr.map_name, map_name, sizeof(attr.map_name));
232 attr.key_size = key_size;
233 attr.value_size = value_size;
234 attr.max_entries = max_entries;
235
236 return skel_sys_bpf(BPF_MAP_CREATE, &attr, attr_sz);
237 }
238
skel_map_update_elem(int fd,const void * key,const void * value,__u64 flags)239 static inline int skel_map_update_elem(int fd, const void *key,
240 const void *value, __u64 flags)
241 {
242 const size_t attr_sz = offsetofend(union bpf_attr, flags);
243 union bpf_attr attr;
244
245 memset(&attr, 0, attr_sz);
246 attr.map_fd = fd;
247 attr.key = (long) key;
248 attr.value = (long) value;
249 attr.flags = flags;
250
251 return skel_sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, attr_sz);
252 }
253
skel_map_delete_elem(int fd,const void * key)254 static inline int skel_map_delete_elem(int fd, const void *key)
255 {
256 const size_t attr_sz = offsetofend(union bpf_attr, flags);
257 union bpf_attr attr;
258
259 memset(&attr, 0, attr_sz);
260 attr.map_fd = fd;
261 attr.key = (long)key;
262
263 return skel_sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
264 }
265
skel_map_get_fd_by_id(__u32 id)266 static inline int skel_map_get_fd_by_id(__u32 id)
267 {
268 const size_t attr_sz = offsetofend(union bpf_attr, flags);
269 union bpf_attr attr;
270
271 memset(&attr, 0, attr_sz);
272 attr.map_id = id;
273
274 return skel_sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz);
275 }
276
skel_raw_tracepoint_open(const char * name,int prog_fd)277 static inline int skel_raw_tracepoint_open(const char *name, int prog_fd)
278 {
279 const size_t attr_sz = offsetofend(union bpf_attr, raw_tracepoint.prog_fd);
280 union bpf_attr attr;
281
282 memset(&attr, 0, attr_sz);
283 attr.raw_tracepoint.name = (long) name;
284 attr.raw_tracepoint.prog_fd = prog_fd;
285
286 return skel_sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, attr_sz);
287 }
288
skel_link_create(int prog_fd,int target_fd,enum bpf_attach_type attach_type)289 static inline int skel_link_create(int prog_fd, int target_fd,
290 enum bpf_attach_type attach_type)
291 {
292 const size_t attr_sz = offsetofend(union bpf_attr, link_create.iter_info_len);
293 union bpf_attr attr;
294
295 memset(&attr, 0, attr_sz);
296 attr.link_create.prog_fd = prog_fd;
297 attr.link_create.target_fd = target_fd;
298 attr.link_create.attach_type = attach_type;
299
300 return skel_sys_bpf(BPF_LINK_CREATE, &attr, attr_sz);
301 }
302
303 #ifdef __KERNEL__
304 #define set_err
305 #else
306 #define set_err err = -errno
307 #endif
308
bpf_load_and_run(struct bpf_load_and_run_opts * opts)309 static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
310 {
311 const size_t prog_load_attr_sz = offsetofend(union bpf_attr, fd_array);
312 const size_t test_run_attr_sz = offsetofend(union bpf_attr, test);
313 int map_fd = -1, prog_fd = -1, key = 0, err;
314 union bpf_attr attr;
315
316 err = map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1);
317 if (map_fd < 0) {
318 opts->errstr = "failed to create loader map";
319 set_err;
320 goto out;
321 }
322
323 err = skel_map_update_elem(map_fd, &key, opts->data, 0);
324 if (err < 0) {
325 opts->errstr = "failed to update loader map";
326 set_err;
327 goto out;
328 }
329
330 memset(&attr, 0, prog_load_attr_sz);
331 attr.prog_type = BPF_PROG_TYPE_SYSCALL;
332 attr.insns = (long) opts->insns;
333 attr.insn_cnt = opts->insns_sz / sizeof(struct bpf_insn);
334 attr.license = (long) "Dual BSD/GPL";
335 memcpy(attr.prog_name, "__loader.prog", sizeof("__loader.prog"));
336 attr.fd_array = (long) &map_fd;
337 attr.log_level = opts->ctx->log_level;
338 attr.log_size = opts->ctx->log_size;
339 attr.log_buf = opts->ctx->log_buf;
340 attr.prog_flags = BPF_F_SLEEPABLE;
341 err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, prog_load_attr_sz);
342 if (prog_fd < 0) {
343 opts->errstr = "failed to load loader prog";
344 set_err;
345 goto out;
346 }
347
348 memset(&attr, 0, test_run_attr_sz);
349 attr.test.prog_fd = prog_fd;
350 attr.test.ctx_in = (long) opts->ctx;
351 attr.test.ctx_size_in = opts->ctx->sz;
352 err = skel_sys_bpf(BPF_PROG_RUN, &attr, test_run_attr_sz);
353 if (err < 0 || (int)attr.test.retval < 0) {
354 opts->errstr = "failed to execute loader prog";
355 if (err < 0) {
356 set_err;
357 } else {
358 err = (int)attr.test.retval;
359 #ifndef __KERNEL__
360 errno = -err;
361 #endif
362 }
363 goto out;
364 }
365 err = 0;
366 out:
367 if (map_fd >= 0)
368 close(map_fd);
369 if (prog_fd >= 0)
370 close(prog_fd);
371 return err;
372 }
373
374 #endif
375