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 (hdr->nmatches > 0) { 453 if (parse_rtattr_nested(tb, hdr->nmatches, rta) < 0) 454 goto errout; 455 456 fprintf(fd, "\n "); 457 if (print_ematch_seq(fd, tb, 1, 1) < 0) 458 goto errout; 459 } 460 461 err = 0; 462 errout: 463 free(tb); 464 return err; 465 } 466 print_ematch(FILE * fd,const struct rtattr * rta)467 int print_ematch(FILE *fd, const struct rtattr *rta) 468 { 469 struct rtattr *tb[TCA_EMATCH_TREE_MAX+1]; 470 struct tcf_ematch_tree_hdr *hdr; 471 472 if (parse_rtattr_nested(tb, TCA_EMATCH_TREE_MAX, rta) < 0) 473 return -1; 474 475 if (tb[TCA_EMATCH_TREE_HDR] == NULL) { 476 fprintf(stderr, "Missing ematch tree header\n"); 477 return -1; 478 } 479 480 if (tb[TCA_EMATCH_TREE_LIST] == NULL) { 481 fprintf(stderr, "Missing ematch tree list\n"); 482 return -1; 483 } 484 485 if (RTA_PAYLOAD(tb[TCA_EMATCH_TREE_HDR]) < sizeof(*hdr)) { 486 fprintf(stderr, "Ematch tree header size mismatch\n"); 487 return -1; 488 } 489 490 hdr = RTA_DATA(tb[TCA_EMATCH_TREE_HDR]); 491 492 return print_ematch_list(fd, hdr, tb[TCA_EMATCH_TREE_LIST]); 493 } 494 bstr_alloc(const char * text)495 struct bstr * bstr_alloc(const char *text) 496 { 497 struct bstr *b = calloc(1, sizeof(*b)); 498 499 if (b == NULL) 500 return NULL; 501 502 b->data = strdup(text); 503 if (b->data == NULL) { 504 free(b); 505 return NULL; 506 } 507 508 b->len = strlen(text); 509 510 return b; 511 } 512 bstrtoul(const struct bstr * b)513 unsigned long bstrtoul(const struct bstr *b) 514 { 515 char *inv = NULL; 516 unsigned long l; 517 char buf[b->len+1]; 518 519 memcpy(buf, b->data, b->len); 520 buf[b->len] = '\0'; 521 522 l = strtoul(buf, &inv, 0); 523 if (l == ULONG_MAX || inv == buf) 524 return ULONG_MAX; 525 526 return l; 527 } 528 bstr_print(FILE * fd,const struct bstr * b,int ascii)529 void bstr_print(FILE *fd, const struct bstr *b, int ascii) 530 { 531 int i; 532 char *s = b->data; 533 534 if (ascii) 535 for (i = 0; i < b->len; i++) 536 fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.'); 537 else { 538 for (i = 0; i < b->len; i++) 539 fprintf(fd, "%02x", s[i]); 540 fprintf(fd, "\""); 541 for (i = 0; i < b->len; i++) 542 fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.'); 543 fprintf(fd, "\""); 544 } 545 } 546 print_ematch_tree(const struct ematch * tree)547 void print_ematch_tree(const struct ematch *tree) 548 { 549 const struct ematch *t; 550 551 for (t = tree; t; t = t->next) { 552 if (t->inverted) 553 printf("NOT "); 554 555 if (t->child) { 556 printf("("); 557 print_ematch_tree(t->child); 558 printf(")"); 559 } else { 560 struct bstr *b; 561 for (b = t->args; b; b = b->next) 562 printf("%s%s", b->data, b->next ? " " : ""); 563 } 564 565 if (t->relation == TCF_EM_REL_AND) 566 printf(" AND "); 567 else if (t->relation == TCF_EM_REL_OR) 568 printf(" OR "); 569 } 570 } 571