1#include <stdio.h>
2#include <sys/types.h>
3#include <sys/stat.h>
4#include <fcntl.h>
5#include <libelf.h>
6#include <gelf.h>
7#include <errno.h>
8#include <unistd.h>
9#include <string.h>
10#include <stdbool.h>
11#include <stdlib.h>
12#include <linux/bpf.h>
13#include <linux/filter.h>
14#include <linux/perf_event.h>
15#include <linux/netlink.h>
16#include <linux/rtnetlink.h>
17#include <sys/types.h>
18#include <sys/socket.h>
19#include <sys/syscall.h>
20#include <sys/ioctl.h>
21#include <sys/mman.h>
22#include <poll.h>
23#include <ctype.h>
24#include "libbpf.h"
25#include "bpf_load.h"
26#include "perf-sys.h"
27
28#define DEBUGFS "/sys/kernel/debug/tracing/"
29
30static char license[128];
31static int kern_version;
32static bool processed_sec[128];
33char bpf_log_buf[BPF_LOG_BUF_SIZE];
34int map_fd[MAX_MAPS];
35int prog_fd[MAX_PROGS];
36int event_fd[MAX_PROGS];
37int prog_cnt;
38int prog_array_fd = -1;
39
40struct bpf_map_def {
41 unsigned int type;
42 unsigned int key_size;
43 unsigned int value_size;
44 unsigned int max_entries;
45 unsigned int map_flags;
46};
47
48static int populate_prog_array(const char *event, int prog_fd)
49{
50 int ind = atoi(event), err;
51
52 err = bpf_map_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);
53 if (err < 0) {
54 printf("failed to store prog_fd in prog_array\n");
55 return -1;
56 }
57 return 0;
58}
59
60static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
61{
62 bool is_socket = strncmp(event, "socket", 6) == 0;
63 bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
64 bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
65 bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
66 bool is_xdp = strncmp(event, "xdp", 3) == 0;
67 bool is_perf_event = strncmp(event, "perf_event", 10) == 0;
68 bool is_cgroup_skb = strncmp(event, "cgroup/skb", 10) == 0;
69 bool is_cgroup_sk = strncmp(event, "cgroup/sock", 11) == 0;
70 size_t insns_cnt = size / sizeof(struct bpf_insn);
71 enum bpf_prog_type prog_type;
72 char buf[256];
73 int fd, efd, err, id;
74 struct perf_event_attr attr = {};
75
76 attr.type = PERF_TYPE_TRACEPOINT;
77 attr.sample_type = PERF_SAMPLE_RAW;
78 attr.sample_period = 1;
79 attr.wakeup_events = 1;
80
81 if (is_socket) {
82 prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
83 } else if (is_kprobe || is_kretprobe) {
84 prog_type = BPF_PROG_TYPE_KPROBE;
85 } else if (is_tracepoint) {
86 prog_type = BPF_PROG_TYPE_TRACEPOINT;
87 } else if (is_xdp) {
88 prog_type = BPF_PROG_TYPE_XDP;
89 } else if (is_perf_event) {
90 prog_type = BPF_PROG_TYPE_PERF_EVENT;
91 } else if (is_cgroup_skb) {
92 prog_type = BPF_PROG_TYPE_CGROUP_SKB;
93 } else if (is_cgroup_sk) {
94 prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
95 } else {
96 printf("Unknown event '%s'\n", event);
97 return -1;
98 }
99
100 fd = bpf_load_program(prog_type, prog, insns_cnt, license, kern_version,
101 bpf_log_buf, BPF_LOG_BUF_SIZE);
102 if (fd < 0) {
103 printf("bpf_load_program() err=%d\n%s", errno, bpf_log_buf);
104 return -1;
105 }
106
107 prog_fd[prog_cnt++] = fd;
108
109 if (is_xdp || is_perf_event || is_cgroup_skb || is_cgroup_sk)
110 return 0;
111
112 if (is_socket) {
113 event += 6;
114 if (*event != '/')
115 return 0;
116 event++;
117 if (!isdigit(*event)) {
118 printf("invalid prog number\n");
119 return -1;
120 }
121 return populate_prog_array(event, fd);
122 }
123
124 if (is_kprobe || is_kretprobe) {
125 if (is_kprobe)
126 event += 7;
127 else
128 event += 10;
129
130 if (*event == 0) {
131 printf("event name cannot be empty\n");
132 return -1;
133 }
134
135 if (isdigit(*event))
136 return populate_prog_array(event, fd);
137
138 snprintf(buf, sizeof(buf),
139 "echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
140 is_kprobe ? 'p' : 'r', event, event);
141 err = system(buf);
142 if (err < 0) {
143 printf("failed to create kprobe '%s' error '%s'\n",
144 event, strerror(errno));
145 return -1;
146 }
147
148 strcpy(buf, DEBUGFS);
149 strcat(buf, "events/kprobes/");
150 strcat(buf, event);
151 strcat(buf, "/id");
152 } else if (is_tracepoint) {
153 event += 11;
154
155 if (*event == 0) {
156 printf("event name cannot be empty\n");
157 return -1;
158 }
159 strcpy(buf, DEBUGFS);
160 strcat(buf, "events/");
161 strcat(buf, event);
162 strcat(buf, "/id");
163 }
164
165 efd = open(buf, O_RDONLY, 0);
166 if (efd < 0) {
167 printf("failed to open event %s\n", event);
168 return -1;
169 }
170
171 err = read(efd, buf, sizeof(buf));
172 if (err < 0 || err >= sizeof(buf)) {
173 printf("read from '%s' failed '%s'\n", event, strerror(errno));
174 return -1;
175 }
176
177 close(efd);
178
179 buf[err] = 0;
180 id = atoi(buf);
181 attr.config = id;
182
183 efd = sys_perf_event_open(&attr, -1, 0, -1, 0);
184 if (efd < 0) {
185 printf("event %d fd %d err %s\n", id, efd, strerror(errno));
186 return -1;
187 }
188 event_fd[prog_cnt - 1] = efd;
189 ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
190 ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
191
192 return 0;
193}
194
195static int load_maps(struct bpf_map_def *maps, int len)
196{
197 int i;
198
199 for (i = 0; i < len / sizeof(struct bpf_map_def); i++) {
200
201 map_fd[i] = bpf_create_map(maps[i].type,
202 maps[i].key_size,
203 maps[i].value_size,
204 maps[i].max_entries,
205 maps[i].map_flags);
206 if (map_fd[i] < 0) {
207 printf("failed to create a map: %d %s\n",
208 errno, strerror(errno));
209 return 1;
210 }
211
212 if (maps[i].type == BPF_MAP_TYPE_PROG_ARRAY)
213 prog_array_fd = map_fd[i];
214 }
215 return 0;
216}
217
218static int get_sec(Elf *elf, int i, GElf_Ehdr *ehdr, char **shname,
219 GElf_Shdr *shdr, Elf_Data **data)
220{
221 Elf_Scn *scn;
222
223 scn = elf_getscn(elf, i);
224 if (!scn)
225 return 1;
226
227 if (gelf_getshdr(scn, shdr) != shdr)
228 return 2;
229
230 *shname = elf_strptr(elf, ehdr->e_shstrndx, shdr->sh_name);
231 if (!*shname || !shdr->sh_size)
232 return 3;
233
234 *data = elf_getdata(scn, 0);
235 if (!*data || elf_getdata(scn, *data) != NULL)
236 return 4;
237
238 return 0;
239}
240
241static int parse_relo_and_apply(Elf_Data *data, Elf_Data *symbols,
242 GElf_Shdr *shdr, struct bpf_insn *insn)
243{
244 int i, nrels;
245
246 nrels = shdr->sh_size / shdr->sh_entsize;
247
248 for (i = 0; i < nrels; i++) {
249 GElf_Sym sym;
250 GElf_Rel rel;
251 unsigned int insn_idx;
252
253 gelf_getrel(data, i, &rel);
254
255 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
256
257 gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym);
258
259 if (insn[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
260 printf("invalid relo for insn[%d].code 0x%x\n",
261 insn_idx, insn[insn_idx].code);
262 return 1;
263 }
264 insn[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
265 insn[insn_idx].imm = map_fd[sym.st_value / sizeof(struct bpf_map_def)];
266 }
267
268 return 0;
269}
270
271int load_bpf_file(char *path)
272{
273 int fd, i;
274 Elf *elf;
275 GElf_Ehdr ehdr;
276 GElf_Shdr shdr, shdr_prog;
277 Elf_Data *data, *data_prog, *symbols = NULL;
278 char *shname, *shname_prog;
279
280 if (elf_version(EV_CURRENT) == EV_NONE)
281 return 1;
282
283 fd = open(path, O_RDONLY, 0);
284 if (fd < 0)
285 return 1;
286
287 elf = elf_begin(fd, ELF_C_READ, NULL);
288
289 if (!elf)
290 return 1;
291
292 if (gelf_getehdr(elf, &ehdr) != &ehdr)
293 return 1;
294
295
296 i = system("echo \"\" > /sys/kernel/debug/tracing/kprobe_events");
297
298
299 for (i = 1; i < ehdr.e_shnum; i++) {
300
301 if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
302 continue;
303
304 if (0)
305 printf("section %d:%s data %p size %zd link %d flags %d\n",
306 i, shname, data->d_buf, data->d_size,
307 shdr.sh_link, (int) shdr.sh_flags);
308
309 if (strcmp(shname, "license") == 0) {
310 processed_sec[i] = true;
311 memcpy(license, data->d_buf, data->d_size);
312 } else if (strcmp(shname, "version") == 0) {
313 processed_sec[i] = true;
314 if (data->d_size != sizeof(int)) {
315 printf("invalid size of version section %zd\n",
316 data->d_size);
317 return 1;
318 }
319 memcpy(&kern_version, data->d_buf, sizeof(int));
320 } else if (strcmp(shname, "maps") == 0) {
321 processed_sec[i] = true;
322 if (load_maps(data->d_buf, data->d_size))
323 return 1;
324 } else if (shdr.sh_type == SHT_SYMTAB) {
325 symbols = data;
326 }
327 }
328
329
330 for (i = 1; i < ehdr.e_shnum; i++) {
331
332 if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
333 continue;
334 if (shdr.sh_type == SHT_REL) {
335 struct bpf_insn *insns;
336
337 if (get_sec(elf, shdr.sh_info, &ehdr, &shname_prog,
338 &shdr_prog, &data_prog))
339 continue;
340
341 if (shdr_prog.sh_type != SHT_PROGBITS ||
342 !(shdr_prog.sh_flags & SHF_EXECINSTR))
343 continue;
344
345 insns = (struct bpf_insn *) data_prog->d_buf;
346
347 processed_sec[shdr.sh_info] = true;
348 processed_sec[i] = true;
349
350 if (parse_relo_and_apply(data, symbols, &shdr, insns))
351 continue;
352
353 if (memcmp(shname_prog, "kprobe/", 7) == 0 ||
354 memcmp(shname_prog, "kretprobe/", 10) == 0 ||
355 memcmp(shname_prog, "tracepoint/", 11) == 0 ||
356 memcmp(shname_prog, "xdp", 3) == 0 ||
357 memcmp(shname_prog, "perf_event", 10) == 0 ||
358 memcmp(shname_prog, "socket", 6) == 0 ||
359 memcmp(shname_prog, "cgroup/", 7) == 0)
360 load_and_attach(shname_prog, insns, data_prog->d_size);
361 }
362 }
363
364
365 for (i = 1; i < ehdr.e_shnum; i++) {
366
367 if (processed_sec[i])
368 continue;
369
370 if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
371 continue;
372
373 if (memcmp(shname, "kprobe/", 7) == 0 ||
374 memcmp(shname, "kretprobe/", 10) == 0 ||
375 memcmp(shname, "tracepoint/", 11) == 0 ||
376 memcmp(shname, "xdp", 3) == 0 ||
377 memcmp(shname, "perf_event", 10) == 0 ||
378 memcmp(shname, "socket", 6) == 0 ||
379 memcmp(shname, "cgroup/", 7) == 0)
380 load_and_attach(shname, data->d_buf, data->d_size);
381 }
382
383 close(fd);
384 return 0;
385}
386
387void read_trace_pipe(void)
388{
389 int trace_fd;
390
391 trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
392 if (trace_fd < 0)
393 return;
394
395 while (1) {
396 static char buf[4096];
397 ssize_t sz;
398
399 sz = read(trace_fd, buf, sizeof(buf));
400 if (sz > 0) {
401 buf[sz] = 0;
402 puts(buf);
403 }
404 }
405}
406
407#define MAX_SYMS 300000
408static struct ksym syms[MAX_SYMS];
409static int sym_cnt;
410
411static int ksym_cmp(const void *p1, const void *p2)
412{
413 return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
414}
415
416int load_kallsyms(void)
417{
418 FILE *f = fopen("/proc/kallsyms", "r");
419 char func[256], buf[256];
420 char symbol;
421 void *addr;
422 int i = 0;
423
424 if (!f)
425 return -ENOENT;
426
427 while (!feof(f)) {
428 if (!fgets(buf, sizeof(buf), f))
429 break;
430 if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
431 break;
432 if (!addr)
433 continue;
434 syms[i].addr = (long) addr;
435 syms[i].name = strdup(func);
436 i++;
437 }
438 sym_cnt = i;
439 qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
440 return 0;
441}
442
443struct ksym *ksym_search(long key)
444{
445 int start = 0, end = sym_cnt;
446 int result;
447
448 while (start < end) {
449 size_t mid = start + (end - start) / 2;
450
451 result = key - syms[mid].addr;
452 if (result < 0)
453 end = mid;
454 else if (result > 0)
455 start = mid + 1;
456 else
457 return &syms[mid];
458 }
459
460 if (start >= 1 && syms[start - 1].addr < key &&
461 key < syms[start].addr)
462
463 return &syms[start - 1];
464
465
466 return &syms[0];
467}
468
469int set_link_xdp_fd(int ifindex, int fd)
470{
471 struct sockaddr_nl sa;
472 int sock, seq = 0, len, ret = -1;
473 char buf[4096];
474 struct nlattr *nla, *nla_xdp;
475 struct {
476 struct nlmsghdr nh;
477 struct ifinfomsg ifinfo;
478 char attrbuf[64];
479 } req;
480 struct nlmsghdr *nh;
481 struct nlmsgerr *err;
482
483 memset(&sa, 0, sizeof(sa));
484 sa.nl_family = AF_NETLINK;
485
486 sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
487 if (sock < 0) {
488 printf("open netlink socket: %s\n", strerror(errno));
489 return -1;
490 }
491
492 if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
493 printf("bind to netlink: %s\n", strerror(errno));
494 goto cleanup;
495 }
496
497 memset(&req, 0, sizeof(req));
498 req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
499 req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
500 req.nh.nlmsg_type = RTM_SETLINK;
501 req.nh.nlmsg_pid = 0;
502 req.nh.nlmsg_seq = ++seq;
503 req.ifinfo.ifi_family = AF_UNSPEC;
504 req.ifinfo.ifi_index = ifindex;
505 nla = (struct nlattr *)(((char *)&req)
506 + NLMSG_ALIGN(req.nh.nlmsg_len));
507 nla->nla_type = NLA_F_NESTED | 43;
508
509 nla_xdp = (struct nlattr *)((char *)nla + NLA_HDRLEN);
510 nla_xdp->nla_type = 1;
511 nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
512 memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
513 nla->nla_len = NLA_HDRLEN + nla_xdp->nla_len;
514
515 req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
516
517 if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
518 printf("send to netlink: %s\n", strerror(errno));
519 goto cleanup;
520 }
521
522 len = recv(sock, buf, sizeof(buf), 0);
523 if (len < 0) {
524 printf("recv from netlink: %s\n", strerror(errno));
525 goto cleanup;
526 }
527
528 for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
529 nh = NLMSG_NEXT(nh, len)) {
530 if (nh->nlmsg_pid != getpid()) {
531 printf("Wrong pid %d, expected %d\n",
532 nh->nlmsg_pid, getpid());
533 goto cleanup;
534 }
535 if (nh->nlmsg_seq != seq) {
536 printf("Wrong seq %d, expected %d\n",
537 nh->nlmsg_seq, seq);
538 goto cleanup;
539 }
540 switch (nh->nlmsg_type) {
541 case NLMSG_ERROR:
542 err = (struct nlmsgerr *)NLMSG_DATA(nh);
543 if (!err->error)
544 continue;
545 printf("nlmsg error %s\n", strerror(-err->error));
546 goto cleanup;
547 case NLMSG_DONE:
548 break;
549 }
550 }
551
552 ret = 0;
553
554cleanup:
555 close(sock);
556 return ret;
557}
558
