1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2 /* Copyright (c) 2019 Netronome Systems, Inc. */
3
4 #include <errno.h>
5 #include <fcntl.h>
6 #include <string.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <net/if.h>
10 #include <sys/utsname.h>
11
12 #include <linux/btf.h>
13 #include <linux/filter.h>
14 #include <linux/kernel.h>
15
16 #include "bpf.h"
17 #include "libbpf.h"
18 #include "libbpf_internal.h"
19
grep(const char * buffer,const char * pattern)20 static bool grep(const char *buffer, const char *pattern)
21 {
22 return !!strstr(buffer, pattern);
23 }
24
get_vendor_id(int ifindex)25 static int get_vendor_id(int ifindex)
26 {
27 char ifname[IF_NAMESIZE], path[64], buf[8];
28 ssize_t len;
29 int fd;
30
31 if (!if_indextoname(ifindex, ifname))
32 return -1;
33
34 snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname);
35
36 fd = open(path, O_RDONLY | O_CLOEXEC);
37 if (fd < 0)
38 return -1;
39
40 len = read(fd, buf, sizeof(buf));
41 close(fd);
42 if (len < 0)
43 return -1;
44 if (len >= (ssize_t)sizeof(buf))
45 return -1;
46 buf[len] = '\0';
47
48 return strtol(buf, NULL, 0);
49 }
50
probe_prog_load(enum bpf_prog_type prog_type,const struct bpf_insn * insns,size_t insns_cnt,char * log_buf,size_t log_buf_sz,__u32 ifindex)51 static int probe_prog_load(enum bpf_prog_type prog_type,
52 const struct bpf_insn *insns, size_t insns_cnt,
53 char *log_buf, size_t log_buf_sz,
54 __u32 ifindex)
55 {
56 LIBBPF_OPTS(bpf_prog_load_opts, opts,
57 .log_buf = log_buf,
58 .log_size = log_buf_sz,
59 .log_level = log_buf ? 1 : 0,
60 .prog_ifindex = ifindex,
61 );
62 int fd, err, exp_err = 0;
63 const char *exp_msg = NULL;
64 char buf[4096];
65
66 switch (prog_type) {
67 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
68 opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
69 break;
70 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
71 opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
72 break;
73 case BPF_PROG_TYPE_SK_LOOKUP:
74 opts.expected_attach_type = BPF_SK_LOOKUP;
75 break;
76 case BPF_PROG_TYPE_KPROBE:
77 opts.kern_version = get_kernel_version();
78 break;
79 case BPF_PROG_TYPE_LIRC_MODE2:
80 opts.expected_attach_type = BPF_LIRC_MODE2;
81 break;
82 case BPF_PROG_TYPE_TRACING:
83 case BPF_PROG_TYPE_LSM:
84 opts.log_buf = buf;
85 opts.log_size = sizeof(buf);
86 opts.log_level = 1;
87 if (prog_type == BPF_PROG_TYPE_TRACING)
88 opts.expected_attach_type = BPF_TRACE_FENTRY;
89 else
90 opts.expected_attach_type = BPF_MODIFY_RETURN;
91 opts.attach_btf_id = 1;
92
93 exp_err = -EINVAL;
94 exp_msg = "attach_btf_id 1 is not a function";
95 break;
96 case BPF_PROG_TYPE_EXT:
97 opts.log_buf = buf;
98 opts.log_size = sizeof(buf);
99 opts.log_level = 1;
100 opts.attach_btf_id = 1;
101
102 exp_err = -EINVAL;
103 exp_msg = "Cannot replace kernel functions";
104 break;
105 case BPF_PROG_TYPE_SYSCALL:
106 opts.prog_flags = BPF_F_SLEEPABLE;
107 break;
108 case BPF_PROG_TYPE_STRUCT_OPS:
109 exp_err = -524; /* -ENOTSUPP */
110 break;
111 case BPF_PROG_TYPE_UNSPEC:
112 case BPF_PROG_TYPE_SOCKET_FILTER:
113 case BPF_PROG_TYPE_SCHED_CLS:
114 case BPF_PROG_TYPE_SCHED_ACT:
115 case BPF_PROG_TYPE_TRACEPOINT:
116 case BPF_PROG_TYPE_XDP:
117 case BPF_PROG_TYPE_PERF_EVENT:
118 case BPF_PROG_TYPE_CGROUP_SKB:
119 case BPF_PROG_TYPE_CGROUP_SOCK:
120 case BPF_PROG_TYPE_LWT_IN:
121 case BPF_PROG_TYPE_LWT_OUT:
122 case BPF_PROG_TYPE_LWT_XMIT:
123 case BPF_PROG_TYPE_SOCK_OPS:
124 case BPF_PROG_TYPE_SK_SKB:
125 case BPF_PROG_TYPE_CGROUP_DEVICE:
126 case BPF_PROG_TYPE_SK_MSG:
127 case BPF_PROG_TYPE_RAW_TRACEPOINT:
128 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
129 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
130 case BPF_PROG_TYPE_SK_REUSEPORT:
131 case BPF_PROG_TYPE_FLOW_DISSECTOR:
132 case BPF_PROG_TYPE_CGROUP_SYSCTL:
133 break;
134 default:
135 return -EOPNOTSUPP;
136 }
137
138 fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts);
139 err = -errno;
140 if (fd >= 0)
141 close(fd);
142 if (exp_err) {
143 if (fd >= 0 || err != exp_err)
144 return 0;
145 if (exp_msg && !strstr(buf, exp_msg))
146 return 0;
147 return 1;
148 }
149 return fd >= 0 ? 1 : 0;
150 }
151
libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type,const void * opts)152 int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts)
153 {
154 struct bpf_insn insns[] = {
155 BPF_MOV64_IMM(BPF_REG_0, 0),
156 BPF_EXIT_INSN()
157 };
158 const size_t insn_cnt = ARRAY_SIZE(insns);
159 int ret;
160
161 if (opts)
162 return libbpf_err(-EINVAL);
163
164 ret = probe_prog_load(prog_type, insns, insn_cnt, NULL, 0, 0);
165 return libbpf_err(ret);
166 }
167
bpf_probe_prog_type(enum bpf_prog_type prog_type,__u32 ifindex)168 bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
169 {
170 struct bpf_insn insns[2] = {
171 BPF_MOV64_IMM(BPF_REG_0, 0),
172 BPF_EXIT_INSN()
173 };
174
175 /* prefer libbpf_probe_bpf_prog_type() unless offload is requested */
176 if (ifindex == 0)
177 return libbpf_probe_bpf_prog_type(prog_type, NULL) == 1;
178
179 if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS)
180 /* nfp returns -EINVAL on exit(0) with TC offload */
181 insns[0].imm = 2;
182
183 errno = 0;
184 probe_prog_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex);
185
186 return errno != EINVAL && errno != EOPNOTSUPP;
187 }
188
libbpf__load_raw_btf(const char * raw_types,size_t types_len,const char * str_sec,size_t str_len)189 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
190 const char *str_sec, size_t str_len)
191 {
192 struct btf_header hdr = {
193 .magic = BTF_MAGIC,
194 .version = BTF_VERSION,
195 .hdr_len = sizeof(struct btf_header),
196 .type_len = types_len,
197 .str_off = types_len,
198 .str_len = str_len,
199 };
200 int btf_fd, btf_len;
201 __u8 *raw_btf;
202
203 btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
204 raw_btf = malloc(btf_len);
205 if (!raw_btf)
206 return -ENOMEM;
207
208 memcpy(raw_btf, &hdr, sizeof(hdr));
209 memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
210 memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
211
212 btf_fd = bpf_btf_load(raw_btf, btf_len, NULL);
213
214 free(raw_btf);
215 return btf_fd;
216 }
217
load_local_storage_btf(void)218 static int load_local_storage_btf(void)
219 {
220 const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
221 /* struct bpf_spin_lock {
222 * int val;
223 * };
224 * struct val {
225 * int cnt;
226 * struct bpf_spin_lock l;
227 * };
228 */
229 __u32 types[] = {
230 /* int */
231 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
232 /* struct bpf_spin_lock */ /* [2] */
233 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
234 BTF_MEMBER_ENC(15, 1, 0), /* int val; */
235 /* struct val */ /* [3] */
236 BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
237 BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
238 BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
239 };
240
241 return libbpf__load_raw_btf((char *)types, sizeof(types),
242 strs, sizeof(strs));
243 }
244
probe_map_create(enum bpf_map_type map_type,__u32 ifindex)245 static int probe_map_create(enum bpf_map_type map_type, __u32 ifindex)
246 {
247 LIBBPF_OPTS(bpf_map_create_opts, opts);
248 int key_size, value_size, max_entries;
249 __u32 btf_key_type_id = 0, btf_value_type_id = 0;
250 int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err;
251
252 opts.map_ifindex = ifindex;
253
254 key_size = sizeof(__u32);
255 value_size = sizeof(__u32);
256 max_entries = 1;
257
258 switch (map_type) {
259 case BPF_MAP_TYPE_STACK_TRACE:
260 value_size = sizeof(__u64);
261 break;
262 case BPF_MAP_TYPE_LPM_TRIE:
263 key_size = sizeof(__u64);
264 value_size = sizeof(__u64);
265 opts.map_flags = BPF_F_NO_PREALLOC;
266 break;
267 case BPF_MAP_TYPE_CGROUP_STORAGE:
268 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
269 key_size = sizeof(struct bpf_cgroup_storage_key);
270 value_size = sizeof(__u64);
271 max_entries = 0;
272 break;
273 case BPF_MAP_TYPE_QUEUE:
274 case BPF_MAP_TYPE_STACK:
275 key_size = 0;
276 break;
277 case BPF_MAP_TYPE_SK_STORAGE:
278 case BPF_MAP_TYPE_INODE_STORAGE:
279 case BPF_MAP_TYPE_TASK_STORAGE:
280 btf_key_type_id = 1;
281 btf_value_type_id = 3;
282 value_size = 8;
283 max_entries = 0;
284 opts.map_flags = BPF_F_NO_PREALLOC;
285 btf_fd = load_local_storage_btf();
286 if (btf_fd < 0)
287 return btf_fd;
288 break;
289 case BPF_MAP_TYPE_RINGBUF:
290 key_size = 0;
291 value_size = 0;
292 max_entries = 4096;
293 break;
294 case BPF_MAP_TYPE_STRUCT_OPS:
295 /* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
296 opts.btf_vmlinux_value_type_id = 1;
297 exp_err = -524; /* -ENOTSUPP */
298 break;
299 case BPF_MAP_TYPE_BLOOM_FILTER:
300 key_size = 0;
301 max_entries = 1;
302 break;
303 case BPF_MAP_TYPE_HASH:
304 case BPF_MAP_TYPE_ARRAY:
305 case BPF_MAP_TYPE_PROG_ARRAY:
306 case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
307 case BPF_MAP_TYPE_PERCPU_HASH:
308 case BPF_MAP_TYPE_PERCPU_ARRAY:
309 case BPF_MAP_TYPE_CGROUP_ARRAY:
310 case BPF_MAP_TYPE_LRU_HASH:
311 case BPF_MAP_TYPE_LRU_PERCPU_HASH:
312 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
313 case BPF_MAP_TYPE_HASH_OF_MAPS:
314 case BPF_MAP_TYPE_DEVMAP:
315 case BPF_MAP_TYPE_DEVMAP_HASH:
316 case BPF_MAP_TYPE_SOCKMAP:
317 case BPF_MAP_TYPE_CPUMAP:
318 case BPF_MAP_TYPE_XSKMAP:
319 case BPF_MAP_TYPE_SOCKHASH:
320 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
321 break;
322 case BPF_MAP_TYPE_UNSPEC:
323 default:
324 return -EOPNOTSUPP;
325 }
326
327 if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
328 map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
329 /* TODO: probe for device, once libbpf has a function to create
330 * map-in-map for offload
331 */
332 if (ifindex)
333 goto cleanup;
334
335 fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
336 sizeof(__u32), sizeof(__u32), 1, NULL);
337 if (fd_inner < 0)
338 goto cleanup;
339
340 opts.inner_map_fd = fd_inner;
341 }
342
343 if (btf_fd >= 0) {
344 opts.btf_fd = btf_fd;
345 opts.btf_key_type_id = btf_key_type_id;
346 opts.btf_value_type_id = btf_value_type_id;
347 }
348
349 fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts);
350 err = -errno;
351
352 cleanup:
353 if (fd >= 0)
354 close(fd);
355 if (fd_inner >= 0)
356 close(fd_inner);
357 if (btf_fd >= 0)
358 close(btf_fd);
359
360 if (exp_err)
361 return fd < 0 && err == exp_err ? 1 : 0;
362 else
363 return fd >= 0 ? 1 : 0;
364 }
365
libbpf_probe_bpf_map_type(enum bpf_map_type map_type,const void * opts)366 int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts)
367 {
368 int ret;
369
370 if (opts)
371 return libbpf_err(-EINVAL);
372
373 ret = probe_map_create(map_type, 0);
374 return libbpf_err(ret);
375 }
376
bpf_probe_map_type(enum bpf_map_type map_type,__u32 ifindex)377 bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
378 {
379 return probe_map_create(map_type, ifindex) == 1;
380 }
381
libbpf_probe_bpf_helper(enum bpf_prog_type prog_type,enum bpf_func_id helper_id,const void * opts)382 int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type, enum bpf_func_id helper_id,
383 const void *opts)
384 {
385 struct bpf_insn insns[] = {
386 BPF_EMIT_CALL((__u32)helper_id),
387 BPF_EXIT_INSN(),
388 };
389 const size_t insn_cnt = ARRAY_SIZE(insns);
390 char buf[4096];
391 int ret;
392
393 if (opts)
394 return libbpf_err(-EINVAL);
395
396 /* we can't successfully load all prog types to check for BPF helper
397 * support, so bail out with -EOPNOTSUPP error
398 */
399 switch (prog_type) {
400 case BPF_PROG_TYPE_TRACING:
401 case BPF_PROG_TYPE_EXT:
402 case BPF_PROG_TYPE_LSM:
403 case BPF_PROG_TYPE_STRUCT_OPS:
404 return -EOPNOTSUPP;
405 default:
406 break;
407 }
408
409 buf[0] = '\0';
410 ret = probe_prog_load(prog_type, insns, insn_cnt, buf, sizeof(buf), 0);
411 if (ret < 0)
412 return libbpf_err(ret);
413
414 /* If BPF verifier doesn't recognize BPF helper ID (enum bpf_func_id)
415 * at all, it will emit something like "invalid func unknown#181".
416 * If BPF verifier recognizes BPF helper but it's not supported for
417 * given BPF program type, it will emit "unknown func bpf_sys_bpf#166".
418 * In both cases, provided combination of BPF program type and BPF
419 * helper is not supported by the kernel.
420 * In all other cases, probe_prog_load() above will either succeed (e.g.,
421 * because BPF helper happens to accept no input arguments or it
422 * accepts one input argument and initial PTR_TO_CTX is fine for
423 * that), or we'll get some more specific BPF verifier error about
424 * some unsatisfied conditions.
425 */
426 if (ret == 0 && (strstr(buf, "invalid func ") || strstr(buf, "unknown func ")))
427 return 0;
428 return 1; /* assume supported */
429 }
430
bpf_probe_helper(enum bpf_func_id id,enum bpf_prog_type prog_type,__u32 ifindex)431 bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type,
432 __u32 ifindex)
433 {
434 struct bpf_insn insns[2] = {
435 BPF_EMIT_CALL(id),
436 BPF_EXIT_INSN()
437 };
438 char buf[4096] = {};
439 bool res;
440
441 probe_prog_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf), ifindex);
442 res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
443
444 if (ifindex) {
445 switch (get_vendor_id(ifindex)) {
446 case 0x19ee: /* Netronome specific */
447 res = res && !grep(buf, "not supported by FW") &&
448 !grep(buf, "unsupported function id");
449 break;
450 default:
451 break;
452 }
453 }
454
455 return res;
456 }
457
458 /*
459 * Probe for availability of kernel commit (5.3):
460 *
461 * c04c0d2b968a ("bpf: increase complexity limit and maximum program size")
462 */
bpf_probe_large_insn_limit(__u32 ifindex)463 bool bpf_probe_large_insn_limit(__u32 ifindex)
464 {
465 struct bpf_insn insns[BPF_MAXINSNS + 1];
466 int i;
467
468 for (i = 0; i < BPF_MAXINSNS; i++)
469 insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1);
470 insns[BPF_MAXINSNS] = BPF_EXIT_INSN();
471
472 errno = 0;
473 probe_prog_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0,
474 ifindex);
475
476 return errno != E2BIG && errno != EINVAL;
477 }
478