1 /*
2 * m_ematch.c Extended Matches
3 *
4 * This program is free software; you can distribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Thomas Graf <tgraf@suug.ch>
10 */
11
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <unistd.h>
15 #include <syslog.h>
16 #include <fcntl.h>
17 #include <sys/socket.h>
18 #include <netinet/in.h>
19 #include <arpa/inet.h>
20 #include <string.h>
21 #include <dlfcn.h>
22 #include <stdarg.h>
23 #include <errno.h>
24
25 #include "utils.h"
26 #include "tc_util.h"
27 #include "m_ematch.h"
28
29 #define EMATCH_MAP "/etc/iproute2/ematch_map"
30
31 static struct ematch_util *ematch_list;
32
33 /* export to bison parser */
34 int ematch_argc;
35 char **ematch_argv;
36 char *ematch_err = NULL;
37 struct ematch *ematch_root;
38
39 static int begin_argc;
40 static char **begin_argv;
41
map_warning(int num,char * kind)42 static inline void map_warning(int num, char *kind)
43 {
44 fprintf(stderr,
45 "Error: Unable to find ematch \"%s\" in %s\n" \
46 "Please assign a unique ID to the ematch kind the suggested " \
47 "entry is:\n" \
48 "\t%d\t%s\n",
49 kind, EMATCH_MAP, num, kind);
50 }
51
lookup_map(__u16 num,char * dst,int len,const char * file)52 static int lookup_map(__u16 num, char *dst, int len, const char *file)
53 {
54 int err = -EINVAL;
55 char buf[512];
56 FILE *fd = fopen(file, "r");
57
58 if (fd == NULL)
59 return -errno;
60
61 while (fgets(buf, sizeof(buf), fd)) {
62 char namebuf[512], *p = buf;
63 int id;
64
65 while (*p == ' ' || *p == '\t')
66 p++;
67 if (*p == '#' || *p == '\n' || *p == 0)
68 continue;
69
70 if (sscanf(p, "%d %s", &id, namebuf) != 2) {
71 fprintf(stderr, "ematch map %s corrupted at %s\n",
72 file, p);
73 goto out;
74 }
75
76 if (id == num) {
77 if (dst)
78 strncpy(dst, namebuf, len - 1);
79 err = 0;
80 goto out;
81 }
82 }
83
84 err = -ENOENT;
85 out:
86 fclose(fd);
87 return err;
88 }
89
lookup_map_id(char * kind,int * dst,const char * file)90 static int lookup_map_id(char *kind, int *dst, const char *file)
91 {
92 int err = -EINVAL;
93 char buf[512];
94 FILE *fd = fopen(file, "r");
95
96 if (fd == NULL)
97 return -errno;
98
99 while (fgets(buf, sizeof(buf), fd)) {
100 char namebuf[512], *p = buf;
101 int id;
102
103 while (*p == ' ' || *p == '\t')
104 p++;
105 if (*p == '#' || *p == '\n' || *p == 0)
106 continue;
107
108 if (sscanf(p, "%d %s", &id, namebuf) != 2) {
109 fprintf(stderr, "ematch map %s corrupted at %s\n",
110 file, p);
111 goto out;
112 }
113
114 if (!strcasecmp(namebuf, kind)) {
115 if (dst)
116 *dst = id;
117 err = 0;
118 goto out;
119 }
120 }
121
122 err = -ENOENT;
123 *dst = 0;
124 out:
125 fclose(fd);
126 return err;
127 }
128
get_ematch_kind(char * kind)129 static struct ematch_util *get_ematch_kind(char *kind)
130 {
131 static void *body;
132 void *dlh;
133 char buf[256];
134 struct ematch_util *e;
135
136 for (e = ematch_list; e; e = e->next) {
137 if (strcmp(e->kind, kind) == 0)
138 return e;
139 }
140
141 snprintf(buf, sizeof(buf), "em_%s.so", kind);
142 dlh = dlopen(buf, RTLD_LAZY);
143 if (dlh == NULL) {
144 dlh = body;
145 if (dlh == NULL) {
146 dlh = body = dlopen(NULL, RTLD_LAZY);
147 if (dlh == NULL)
148 return NULL;
149 }
150 }
151
152 snprintf(buf, sizeof(buf), "%s_ematch_util", kind);
153 e = dlsym(dlh, buf);
154 if (e == NULL)
155 return NULL;
156
157 e->next = ematch_list;
158 ematch_list = e;
159
160 return e;
161 }
162
get_ematch_kind_num(__u16 kind)163 static struct ematch_util *get_ematch_kind_num(__u16 kind)
164 {
165 char name[32];
166
167 if (lookup_map(kind, name, sizeof(name), EMATCH_MAP) < 0)
168 return NULL;
169
170 return get_ematch_kind(name);
171 }
172
parse_tree(struct nlmsghdr * n,struct ematch * tree)173 static int parse_tree(struct nlmsghdr *n, struct ematch *tree)
174 {
175 int index = 1;
176 struct ematch *t;
177
178 for (t = tree; t; t = t->next) {
179 struct rtattr *tail = NLMSG_TAIL(n);
180 struct tcf_ematch_hdr hdr = {
181 .flags = t->relation
182 };
183
184 if (t->inverted)
185 hdr.flags |= TCF_EM_INVERT;
186
187 addattr_l(n, MAX_MSG, index++, NULL, 0);
188
189 if (t->child) {
190 __u32 r = t->child_ref;
191 addraw_l(n, MAX_MSG, &hdr, sizeof(hdr));
192 addraw_l(n, MAX_MSG, &r, sizeof(r));
193 } else {
194 int num = 0, err;
195 char buf[64];
196 struct ematch_util *e;
197
198 if (t->args == NULL)
199 return -1;
200
201 strncpy(buf, (char*) t->args->data, sizeof(buf)-1);
202 e = get_ematch_kind(buf);
203 if (e == NULL) {
204 fprintf(stderr, "Unknown ematch \"%s\"\n",
205 buf);
206 return -1;
207 }
208
209 err = lookup_map_id(buf, &num, EMATCH_MAP);
210 if (err < 0) {
211 if (err == -ENOENT)
212 map_warning(e->kind_num, buf);
213 return err;
214 }
215
216 hdr.kind = num;
217 if (e->parse_eopt(n, &hdr, t->args->next) < 0)
218 return -1;
219 }
220
221 tail->rta_len = (void*) NLMSG_TAIL(n) - (void*) tail;
222 }
223
224 return 0;
225 }
226
flatten_tree(struct ematch * head,struct ematch * tree)227 static int flatten_tree(struct ematch *head, struct ematch *tree)
228 {
229 int i, count = 0;
230 struct ematch *t;
231
232 for (;;) {
233 count++;
234
235 if (tree->child) {
236 for (t = head; t->next; t = t->next);
237 t->next = tree->child;
238 count += flatten_tree(head, tree->child);
239 }
240
241 if (tree->relation == 0)
242 break;
243
244 tree = tree->next;
245 }
246
247 for (i = 0, t = head; t; t = t->next, i++)
248 t->index = i;
249
250 for (t = head; t; t = t->next)
251 if (t->child)
252 t->child_ref = t->child->index;
253
254 return count;
255 }
256
em_parse_error(int err,struct bstr * args,struct bstr * carg,struct ematch_util * e,char * fmt,...)257 int em_parse_error(int err, struct bstr *args, struct bstr *carg,
258 struct ematch_util *e, char *fmt, ...)
259 {
260 va_list a;
261
262 va_start(a, fmt);
263 vfprintf(stderr, fmt, a);
264 va_end(a);
265
266 if (ematch_err)
267 fprintf(stderr, ": %s\n... ", ematch_err);
268 else
269 fprintf(stderr, "\n... ");
270
271 while (ematch_argc < begin_argc) {
272 if (ematch_argc == (begin_argc - 1))
273 fprintf(stderr, ">>%s<< ", *begin_argv);
274 else
275 fprintf(stderr, "%s ", *begin_argv);
276 begin_argv++;
277 begin_argc--;
278 }
279
280 fprintf(stderr, "...\n");
281
282 if (args) {
283 fprintf(stderr, "... %s(", e->kind);
284 while (args) {
285 fprintf(stderr, "%s", args == carg ? ">>" : "");
286 bstr_print(stderr, args, 1);
287 fprintf(stderr, "%s%s", args == carg ? "<<" : "",
288 args->next ? " " : "");
289 args = args->next;
290 }
291 fprintf(stderr, ")...\n");
292
293 }
294
295 if (e == NULL) {
296 fprintf(stderr,
297 "Usage: EXPR\n" \
298 "where: EXPR := TERM [ { and | or } EXPR ]\n" \
299 " TERM := [ not ] { MATCH | '(' EXPR ')' }\n" \
300 " MATCH := module '(' ARGS ')'\n" \
301 " ARGS := ARG1 ARG2 ...\n" \
302 "\n" \
303 "Example: a(x y) and not (b(x) or c(x y z))\n");
304 } else
305 e->print_usage(stderr);
306
307 return -err;
308 }
309
free_ematch_err(void)310 static inline void free_ematch_err(void)
311 {
312 if (ematch_err) {
313 free(ematch_err);
314 ematch_err = NULL;
315 }
316 }
317
318 extern int ematch_parse(void);
319
parse_ematch(int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)320 int parse_ematch(int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
321 {
322 begin_argc = ematch_argc = *argc_p;
323 begin_argv = ematch_argv = *argv_p;
324
325 if (ematch_parse()) {
326 int err = em_parse_error(EINVAL, NULL, NULL, NULL,
327 "Parse error");
328 free_ematch_err();
329 return err;
330 }
331
332 free_ematch_err();
333
334 /* undo look ahead by parser */
335 ematch_argc++;
336 ematch_argv--;
337
338 if (ematch_root) {
339 struct rtattr *tail, *tail_list;
340
341 struct tcf_ematch_tree_hdr hdr = {
342 .nmatches = flatten_tree(ematch_root, ematch_root),
343 .progid = TCF_EM_PROG_TC
344 };
345
346 tail = NLMSG_TAIL(n);
347 addattr_l(n, MAX_MSG, tca_id, NULL, 0);
348 addattr_l(n, MAX_MSG, TCA_EMATCH_TREE_HDR, &hdr, sizeof(hdr));
349
350 tail_list = NLMSG_TAIL(n);
351 addattr_l(n, MAX_MSG, TCA_EMATCH_TREE_LIST, NULL, 0);
352
353 if (parse_tree(n, ematch_root) < 0)
354 return -1;
355
356 tail_list->rta_len = (void*) NLMSG_TAIL(n) - (void*) tail_list;
357 tail->rta_len = (void*) NLMSG_TAIL(n) - (void*) tail;
358 }
359
360 *argc_p = ematch_argc;
361 *argv_p = ematch_argv;
362
363 return 0;
364 }
365
print_ematch_seq(FILE * fd,struct rtattr ** tb,int start,int prefix)366 static int print_ematch_seq(FILE *fd, struct rtattr **tb, int start,
367 int prefix)
368 {
369 int n, i = start;
370 struct tcf_ematch_hdr *hdr;
371 int dlen;
372 void *data;
373
374 for (;;) {
375 if (tb[i] == NULL)
376 return -1;
377
378 dlen = RTA_PAYLOAD(tb[i]) - sizeof(*hdr);
379 data = (void *) RTA_DATA(tb[i]) + sizeof(*hdr);
380
381 if (dlen < 0)
382 return -1;
383
384 hdr = RTA_DATA(tb[i]);
385
386 if (hdr->flags & TCF_EM_INVERT)
387 fprintf(fd, "NOT ");
388
389 if (hdr->kind == 0) {
390 __u32 ref;
391
392 if (dlen < sizeof(__u32))
393 return -1;
394
395 ref = *(__u32 *) data;
396 fprintf(fd, "(\n");
397 for (n = 0; n <= prefix; n++)
398 fprintf(fd, " ");
399 if (print_ematch_seq(fd, tb, ref + 1, prefix + 1) < 0)
400 return -1;
401 for (n = 0; n < prefix; n++)
402 fprintf(fd, " ");
403 fprintf(fd, ") ");
404
405 } else {
406 struct ematch_util *e;
407
408 e = get_ematch_kind_num(hdr->kind);
409 if (e == NULL)
410 fprintf(fd, "[unknown ematch %d]\n",
411 hdr->kind);
412 else {
413 fprintf(fd, "%s(", e->kind);
414 if (e->print_eopt(fd, hdr, data, dlen) < 0)
415 return -1;
416 fprintf(fd, ")\n");
417 }
418 if (hdr->flags & TCF_EM_REL_MASK)
419 for (n = 0; n < prefix; n++)
420 fprintf(fd, " ");
421 }
422
423 switch (hdr->flags & TCF_EM_REL_MASK) {
424 case TCF_EM_REL_AND:
425 fprintf(fd, "AND ");
426 break;
427
428 case TCF_EM_REL_OR:
429 fprintf(fd, "OR ");
430 break;
431
432 default:
433 return 0;
434 }
435
436 i++;
437 }
438
439 return 0;
440 }
441
print_ematch_list(FILE * fd,struct tcf_ematch_tree_hdr * hdr,struct rtattr * rta)442 static int print_ematch_list(FILE *fd, struct tcf_ematch_tree_hdr *hdr,
443 struct rtattr *rta)
444 {
445 int err = -1;
446 struct rtattr **tb;
447
448 tb = malloc((hdr->nmatches + 1) * sizeof(struct rtattr *));
449 if (tb == NULL)
450 return -1;
451
452 if (parse_rtattr_nested(tb, hdr->nmatches, rta) < 0)
453 goto errout;
454
455 fprintf(fd, "\n ");
456 if (print_ematch_seq(fd, tb, 1, 1) < 0)
457 goto errout;
458
459 err = 0;
460 errout:
461 free(tb);
462 return err;
463 }
464
print_ematch(FILE * fd,const struct rtattr * rta)465 int print_ematch(FILE *fd, const struct rtattr *rta)
466 {
467 struct rtattr *tb[TCA_EMATCH_TREE_MAX+1];
468 struct tcf_ematch_tree_hdr *hdr;
469
470 if (parse_rtattr_nested(tb, TCA_EMATCH_TREE_MAX, rta) < 0)
471 return -1;
472
473 if (tb[TCA_EMATCH_TREE_HDR] == NULL) {
474 fprintf(stderr, "Missing ematch tree header\n");
475 return -1;
476 }
477
478 if (tb[TCA_EMATCH_TREE_LIST] == NULL) {
479 fprintf(stderr, "Missing ematch tree list\n");
480 return -1;
481 }
482
483 if (RTA_PAYLOAD(tb[TCA_EMATCH_TREE_HDR]) < sizeof(*hdr)) {
484 fprintf(stderr, "Ematch tree header size mismatch\n");
485 return -1;
486 }
487
488 hdr = RTA_DATA(tb[TCA_EMATCH_TREE_HDR]);
489
490 return print_ematch_list(fd, hdr, tb[TCA_EMATCH_TREE_LIST]);
491 }
492
bstr_alloc(const char * text)493 struct bstr * bstr_alloc(const char *text)
494 {
495 struct bstr *b = calloc(1, sizeof(*b));
496
497 if (b == NULL)
498 return NULL;
499
500 b->data = strdup(text);
501 if (b->data == NULL) {
502 free(b);
503 return NULL;
504 }
505
506 b->len = strlen(text);
507
508 return b;
509 }
510
bstrtoul(const struct bstr * b)511 unsigned long bstrtoul(const struct bstr *b)
512 {
513 char *inv = NULL;
514 unsigned long l;
515 char buf[b->len+1];
516
517 memcpy(buf, b->data, b->len);
518 buf[b->len] = '\0';
519
520 l = strtoul(buf, &inv, 0);
521 if (l == ULONG_MAX || inv == buf)
522 return ULONG_MAX;
523
524 return l;
525 }
526
bstr_print(FILE * fd,const struct bstr * b,int ascii)527 void bstr_print(FILE *fd, const struct bstr *b, int ascii)
528 {
529 int i;
530 char *s = b->data;
531
532 if (ascii)
533 for (i = 0; i < b->len; i++)
534 fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.');
535 else {
536 for (i = 0; i < b->len; i++)
537 fprintf(fd, "%02x", s[i]);
538 fprintf(fd, "\"");
539 for (i = 0; i < b->len; i++)
540 fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.');
541 fprintf(fd, "\"");
542 }
543 }
544
print_ematch_tree(const struct ematch * tree)545 void print_ematch_tree(const struct ematch *tree)
546 {
547 const struct ematch *t;
548
549 for (t = tree; t; t = t->next) {
550 if (t->inverted)
551 printf("NOT ");
552
553 if (t->child) {
554 printf("(");
555 print_ematch_tree(t->child);
556 printf(")");
557 } else {
558 struct bstr *b;
559 for (b = t->args; b; b = b->next)
560 printf("%s%s", b->data, b->next ? " " : "");
561 }
562
563 if (t->relation == TCF_EM_REL_AND)
564 printf(" AND ");
565 else if (t->relation == TCF_EM_REL_OR)
566 printf(" OR ");
567 }
568 }
569