tc/m_ipt.c

   1 /*
   2  * m_ipt.c      iptables based targets
   3  *              utilities mostly ripped from iptables <duh, its the linux way>
   4  *
   5  *              This program is free software; you can distribute it and/or
   6  *              modify it under the terms of the GNU General Public License
   7  *              as published by the Free Software Foundation; either version
   8  *              2 of the License, or (at your option) any later version.
   9  *
  10  * Authors:  J Hadi Salim (hadi@cyberus.ca)
  11  */
  12
  13 #include <syslog.h>
  14 #include <sys/socket.h>
  15 #include <netinet/in.h>
  16 #include <arpa/inet.h>
  17 #include <linux/if.h>
  18 #include <iptables.h>
  19 #include <linux/netfilter.h>
  20 #include <linux/netfilter_ipv4/ip_tables.h>
  21 #include "utils.h"
  22 #include "tc_util.h"
  23 #include <linux/tc_act/tc_ipt.h>
  24 #include <stdio.h>
  25 #include <dlfcn.h>
  26 #include <getopt.h>
  27 #include <errno.h>
  28 #include <string.h>
  29 #include <netdb.h>
  30 #include <stdlib.h>
  31 #include <ctype.h>
  32 #include <stdarg.h>
  33 #include <limits.h>
  34 #include <unistd.h>
  35 #include <fcntl.h>
  36 #include <sys/wait.h>
  37
  38 static const char *pname = "tc-ipt";
  39 static const char *tname = "mangle";
  40 static const char *pversion = "0.1";
  41
  42 static const char *ipthooks[] = {
  43         "NF_IP_PRE_ROUTING",
  44         "NF_IP_LOCAL_IN",
  45         "NF_IP_FORWARD",
  46         "NF_IP_LOCAL_OUT",
  47         "NF_IP_POST_ROUTING",
  48 };
  49
  50 static struct option original_opts[] = {
  51         {"jump", 1, 0, 'j'},
  52         {0, 0, 0, 0}
  53 };
  54
  55 static struct iptables_target *t_list = NULL;
  56 static struct option *opts = original_opts;
  57 static unsigned int global_option_offset = 0;
  58 #define OPTION_OFFSET 256
  59
  60 char *lib_dir;
  61
  62 void
  63 register_target(struct iptables_target *me)
  64 {
  65 /*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
  66 */
  67         me->next = t_list;
  68         t_list = me;
  69
  70 }
  71
  72 void
  73 xtables_register_target(struct iptables_target *me)
  74 {
  75         me->next = t_list;
  76         t_list = me;
  77 }
  78
  79 void
  80 exit_tryhelp(int status)
  81 {
  82         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  83                 pname, pname);
  84         exit(status);
  85 }
  86
  87 void
  88 exit_error(enum exittype status, char *msg, ...)
  89 {
  90         va_list args;
  91
  92         va_start(args, msg);
  93         fprintf(stderr, "%s v%s: ", pname, pversion);
  94         vfprintf(stderr, msg, args);
  95         va_end(args);
  96         fprintf(stderr, "\n");
  97         if (status == PARAMETER_PROBLEM)
  98                 exit_tryhelp(status);
  99         if (status == VERSION_PROBLEM)
 100                 fprintf(stderr,
 101                         "Perhaps iptables or your kernel needs to be upgraded.\n");
 102         exit(status);
 103 }
 104
 105 /* stolen from iptables 1.2.11
 106 They should really have them as a library so i can link to them
 107 Email them next time i remember
 108 */
 109
 110 char *
 111 addr_to_dotted(const struct in_addr *addrp)
 112 {
 113         static char buf[20];
 114         const unsigned char *bytep;
 115
 116         bytep = (const unsigned char *) &(addrp->s_addr);
 117         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 118         return buf;
 119 }
 120
 121 int string_to_number_ll(const char *s, unsigned long long min,
 122                         unsigned long long max,
 123                  unsigned long long *ret)
 124 {
 125         unsigned long long number;
 126         char *end;
 127
 128         /* Handle hex, octal, etc. */
 129         errno = 0;
 130         number = strtoull(s, &end, 0);
 131         if (*end == '\0' && end != s) {
 132                 /* we parsed a number, let's see if we want this */
 133                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 134                         *ret = number;
 135                         return 0;
 136                 }
 137         }
 138         return -1;
 139 }
 140
 141 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 142                        unsigned long *ret)
 143 {
 144         int result;
 145         unsigned long long number;
 146
 147         result = string_to_number_ll(s, min, max, &number);
 148         *ret = (unsigned long)number;
 149
 150         return result;
 151 }
 152
 153 int string_to_number(const char *s, unsigned int min, unsigned int max,
 154                 unsigned int *ret)
 155 {
 156         int result;
 157         unsigned long number;
 158
 159         result = string_to_number_l(s, min, max, &number);
 160         *ret = (unsigned int)number;
 161
 162         return result;
 163 }
 164
 165 static void free_opts(struct option *opts)
 166 {
 167         if (opts != original_opts) {
 168                 free(opts);
 169                 opts = original_opts;
 170                 global_option_offset = 0;
 171         }
 172 }
 173
 174 static struct option *
 175 merge_options(struct option *oldopts, const struct option *newopts,
 176               unsigned int *option_offset)
 177 {
 178         struct option *merge;
 179         unsigned int num_old, num_new, i;
 180
 181         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 182         for (num_new = 0; newopts[num_new].name; num_new++) ;
 183
 184         *option_offset = global_option_offset + OPTION_OFFSET;
 185
 186         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 187         memcpy(merge, oldopts, num_old * sizeof (struct option));
 188         for (i = 0; i < num_new; i++) {
 189                 merge[num_old + i] = newopts[i];
 190                 merge[num_old + i].val += *option_offset;
 191         }
 192         memset(merge + num_old + num_new, 0, sizeof (struct option));
 193
 194         return merge;
 195 }
 196
 197 static void *
 198 fw_calloc(size_t count, size_t size)
 199 {
 200         void *p;
 201
 202         if ((p = (void *) calloc(count, size)) == NULL) {
 203                 perror("iptables: calloc failed");
 204                 exit(1);
 205         }
 206         return p;
 207 }
 208
 209 static struct iptables_target *
 210 find_t(char *name)
 211 {
 212         struct iptables_target *m;
 213         for (m = t_list; m; m = m->next) {
 214                 if (strcmp(m->name, name) == 0)
 215                         return m;
 216         }
 217
 218         return NULL;
 219 }
 220
 221 static struct iptables_target *
 222 get_target_name(const char *name)
 223 {
 224         void *handle;
 225         char *error;
 226         char *new_name, *lname;
 227         struct iptables_target *m;
 228         char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
 229
 230         new_name = malloc(strlen(name) + 1);
 231         lname = malloc(strlen(name) + 1);
 232         if (new_name)
 233                 memset(new_name, '\0', strlen(name) + 1);
 234         else
 235                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 236
 237         if (lname)
 238                 memset(lname, '\0', strlen(name) + 1);
 239         else
 240                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 241
 242         strcpy(new_name, name);
 243         strcpy(lname, name);
 244
 245         if (isupper(lname[0])) {
 246                 int i;
 247                 for (i = 0; i < strlen(name); i++) {
 248                         lname[i] = tolower(lname[i]);
 249                 }
 250         }
 251
 252         if (islower(new_name[0])) {
 253                 int i;
 254                 for (i = 0; i < strlen(new_name); i++) {
 255                         new_name[i] = toupper(new_name[i]);
 256                 }
 257         }
 258
 259         /* try libxt_xx first */
 260         sprintf(path, "%s/libxt_%s.so", lib_dir, new_name);
 261         handle = dlopen(path, RTLD_LAZY);
 262         if (!handle) {
 263                 /* try libipt_xx next */
 264                 sprintf(path, "%s/libipt_%s.so", lib_dir, new_name);
 265                 handle = dlopen(path, RTLD_LAZY);
 266
 267                 if (!handle) {
 268                         sprintf(path, "%s/libxt_%s.so", lib_dir , lname);
 269                         handle = dlopen(path, RTLD_LAZY);
 270                 }
 271
 272                 if (!handle) {
 273                         sprintf(path, "%s/libipt_%s.so", lib_dir , lname);
 274                         handle = dlopen(path, RTLD_LAZY);
 275                 }
 276                 /* ok, lets give up .. */
 277                 if (!handle) {
 278                         fputs(dlerror(), stderr);
 279                         printf("\n");
 280                         free(new_name);
 281                         return NULL;
 282                 }
 283         }
 284
 285         m = dlsym(handle, new_name);
 286         if ((error = dlerror()) != NULL) {
 287                 m = (struct iptables_target *) dlsym(handle, lname);
 288                 if ((error = dlerror()) != NULL) {
 289                         m = find_t(new_name);
 290                         if (NULL == m) {
 291                                 m = find_t(lname);
 292                                 if (NULL == m) {
 293                                         fputs(error, stderr);
 294                                         fprintf(stderr, "\n");
 295                                         dlclose(handle);
 296                                         free(new_name);
 297                                         return NULL;
 298                                 }
 299                         }
 300                 }
 301         }
 302
 303         free(new_name);
 304         return m;
 305 }
 306
 307
 308 struct in_addr *dotted_to_addr(const char *dotted)
 309 {
 310         static struct in_addr addr;
 311         unsigned char *addrp;
 312         char *p, *q;
 313         unsigned int onebyte;
 314         int i;
 315         char buf[20];
 316
 317         /* copy dotted string, because we need to modify it */
 318         strncpy(buf, dotted, sizeof (buf) - 1);
 319         addrp = (unsigned char *) &(addr.s_addr);
 320
 321         p = buf;
 322         for (i = 0; i < 3; i++) {
 323                 if ((q = strchr(p, '.')) == NULL)
 324                         return (struct in_addr *) NULL;
 325
 326                 *q = '\0';
 327                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 328                         return (struct in_addr *) NULL;
 329
 330                 addrp[i] = (unsigned char) onebyte;
 331                 p = q + 1;
 332         }
 333
 334         /* we've checked 3 bytes, now we check the last one */
 335         if (string_to_number(p, 0, 255, &onebyte) == -1)
 336                 return (struct in_addr *) NULL;
 337
 338         addrp[3] = (unsigned char) onebyte;
 339
 340         return &addr;
 341 }
 342
 343 static void set_revision(char *name, u_int8_t revision)
 344 {
 345         /* Old kernel sources don't have ".revision" field,
 346         *  but we stole a byte from name. */
 347         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 348         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 349 }
 350
 351 /*
 352  * we may need to check for version mismatch
 353 */
 354 int
 355 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 356 {
 357         unsigned int nfcache = 0;
 358
 359         if (target) {
 360                 size_t size;
 361
 362                 size =
 363                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 364
 365                 if (NULL == t) {
 366                         target->t = fw_calloc(1, size);
 367                         target->t->u.target_size = size;
 368
 369                         if (target->init != NULL)
 370                                 target->init(target->t, &nfcache);
 371                         set_revision(target->t->u.user.name, target->revision);
 372                 } else {
 373                         target->t = t;
 374                 }
 375                 strcpy(target->t->u.user.name, target->name);
 376                 return 0;
 377         }
 378
 379         return -1;
 380 }
 381
 382 static int parse_ipt(struct action_util *a,int *argc_p,
 383                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 384 {
 385         struct iptables_target *m = NULL;
 386         struct ipt_entry fw;
 387         struct rtattr *tail;
 388         int c;
 389         int rargc = *argc_p;
 390         char **argv = *argv_p;
 391         int argc = 0, iargc = 0;
 392         char k[16];
 393         int res = -1;
 394         int size = 0;
 395         int iok = 0, ok = 0;
 396         __u32 hook = 0, index = 0;
 397         res = 0;
 398
 399         lib_dir = getenv("IPTABLES_LIB_DIR");
 400         if (!lib_dir)
 401                 lib_dir = IPT_LIB_DIR;
 402
 403         {
 404                 int i;
 405                 for (i = 0; i < rargc; i++) {
 406                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 407                                 break;
 408                         }
 409                 }
 410                 iargc = argc = i;
 411         }
 412
 413         if (argc <= 2) {
 414                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 415                 return -1;
 416         }
 417
 418         while (1) {
 419                 c = getopt_long(argc, argv, "j:", opts, NULL);
 420                 if (c == -1)
 421                         break;
 422                 switch (c) {
 423                 case 'j':
 424                         m = get_target_name(optarg);
 425                         if (NULL != m) {
 426
 427                                 if (0 > build_st(m, NULL)) {
 428                                         printf(" %s error \n", m->name);
 429                                         return -1;
 430                                 }
 431                                 opts =
 432                                     merge_options(opts, m->extra_opts,
 433                                                   &m->option_offset);
 434                         } else {
 435                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 436                                 return -1;
 437                         }
 438                         ok++;
 439                         break;
 440
 441                 default:
 442                         memset(&fw, 0, sizeof (fw));
 443                         if (m) {
 444                                 m->parse(c - m->option_offset, argv, 0,
 445                                          &m->tflags, NULL, &m->t);
 446                         } else {
 447                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 448                                 return -1;
 449
 450                         }
 451                         ok++;
 452                         break;
 453
 454                 }
 455         }
 456
 457         if (iargc > optind) {
 458                 if (matches(argv[optind], "index") == 0) {
 459                         if (get_u32(&index, argv[optind + 1], 10)) {
 460                                 fprintf(stderr, "Illegal \"index\"\n");
 461                                 free_opts(opts);
 462                                 return -1;
 463                         }
 464                         iok++;
 465
 466                         optind += 2;
 467                 }
 468         }
 469
 470         if (!ok && !iok) {
 471                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 472                 return -1;
 473         }
 474
 475         /* check that we passed the correct parameters to the target */
 476         if (m)
 477                 m->final_check(m->tflags);
 478
 479         {
 480                 struct tcmsg *t = NLMSG_DATA(n);
 481                 if (t->tcm_parent != TC_H_ROOT
 482                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 483                         hook = NF_IP_PRE_ROUTING;
 484                 } else {
 485                         hook = NF_IP_POST_ROUTING;
 486                 }
 487         }
 488
 489         tail = NLMSG_TAIL(n);
 490         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 491         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 492         fprintf(stdout, "\ttarget: ");
 493
 494         if (m)
 495                 m->print(NULL, m->t, 0);
 496         fprintf(stdout, " index %d\n", index);
 497
 498         if (strlen(tname) > 16) {
 499                 size = 16;
 500                 k[15] = 0;
 501         } else {
 502                 size = 1 + strlen(tname);
 503         }
 504         strncpy(k, tname, size);
 505
 506         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 507         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 508         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 509         if (m)
 510                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 511         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 512
 513         argc -= optind;
 514         argv += optind;
 515         *argc_p = rargc - iargc;
 516         *argv_p = argv;
 517
 518         optind = 0;
 519         free_opts(opts);
 520         /* Clear flags if target will be used again */
 521         m->tflags=0;
 522         m->used=0;
 523         /* Free allocated memory */
 524         if (m->t)
 525             free(m->t);
 526
 527
 528         return 0;
 529
 530 }
 531
 532 static int
 533 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 534 {
 535         struct rtattr *tb[TCA_IPT_MAX + 1];
 536         struct ipt_entry_target *t = NULL;
 537
 538         if (arg == NULL)
 539                 return -1;
 540
 541         lib_dir = getenv("IPTABLES_LIB_DIR");
 542         if (!lib_dir)
 543                 lib_dir = IPT_LIB_DIR;
 544
 545         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 546
 547         if (tb[TCA_IPT_TABLE] == NULL) {
 548                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 549         } else {
 550                 fprintf(f, "tablename: %s ",
 551                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 552         }
 553
 554         if (tb[TCA_IPT_HOOK] == NULL) {
 555                 fprintf(f, "[NULL ipt hook name ]\n ");
 556                 return -1;
 557         } else {
 558                 __u32 hook;
 559                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 560                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 561         }
 562
 563         if (tb[TCA_IPT_TARG] == NULL) {
 564                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 565                 return -1;
 566         } else {
 567                 struct iptables_target *m = NULL;
 568                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 569                 m = get_target_name(t->u.user.name);
 570                 if (NULL != m) {
 571                         if (0 > build_st(m, t)) {
 572                                 fprintf(stderr, " %s error \n", m->name);
 573                                 return -1;
 574                         }
 575
 576                         opts =
 577                             merge_options(opts, m->extra_opts,
 578                                           &m->option_offset);
 579                 } else {
 580                         fprintf(stderr, " failed to find target %s\n\n",
 581                                 t->u.user.name);
 582                         return -1;
 583                 }
 584                 fprintf(f, "\ttarget ");
 585                 m->print(NULL, m->t, 0);
 586                 if (tb[TCA_IPT_INDEX] == NULL) {
 587                         fprintf(f, " [NULL ipt target index ]\n");
 588                 } else {
 589                         __u32 index;
 590                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 591                         fprintf(f, " \n\tindex %d", index);
 592                 }
 593
 594                 if (tb[TCA_IPT_CNT]) {
 595                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 596                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 597                 }
 598                 if (show_stats) {
 599                         if (tb[TCA_IPT_TM]) {
 600                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 601                                 print_tm(f,tm);
 602                         }
 603                 }
 604                 fprintf(f, " \n");
 605
 606         }
 607         free_opts(opts);
 608
 609         return 0;
 610 }
 611
 612 struct action_util ipt_action_util = {
 613         .id = "ipt",
 614         .parse_aopt = parse_ipt,
 615         .print_aopt = print_ipt,
 616 };
 617