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 <unistd.h>
  34 #include <fcntl.h>
  35 #include <sys/wait.h>
  36
  37 static const char *pname = "tc-ipt";
  38 static const char *tname = "mangle";
  39 static const char *pversion = "0.1";
  40
  41 static const char *ipthooks[] = {
  42         "NF_IP_PRE_ROUTING",
  43         "NF_IP_LOCAL_IN",
  44         "NF_IP_FORWARD",
  45         "NF_IP_LOCAL_OUT",
  46         "NF_IP_POST_ROUTING",
  47 };
  48
  49 static struct option original_opts[] = {
  50         {"jump", 1, 0, 'j'},
  51         {0, 0, 0, 0}
  52 };
  53
  54 static struct iptables_target *t_list = NULL;
  55 static struct option *opts = original_opts;
  56 static unsigned int global_option_offset = 0;
  57 #define OPTION_OFFSET 256
  58
  59 char *lib_dir;
  60
  61 void
  62 register_target(struct iptables_target *me)
  63 {
  64 /*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
  65 */
  66         me->next = t_list;
  67         t_list = me;
  68
  69 }
  70
  71 void
  72 xtables_register_target(struct iptables_target *me)
  73 {
  74         me->next = t_list;
  75         t_list = me;
  76 }
  77
  78 void
  79 exit_tryhelp(int status)
  80 {
  81         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  82                 pname, pname);
  83         exit(status);
  84 }
  85
  86 void
  87 exit_error(enum exittype status, char *msg, ...)
  88 {
  89         va_list args;
  90
  91         va_start(args, msg);
  92         fprintf(stderr, "%s v%s: ", pname, pversion);
  93         vfprintf(stderr, msg, args);
  94         va_end(args);
  95         fprintf(stderr, "\n");
  96         if (status == PARAMETER_PROBLEM)
  97                 exit_tryhelp(status);
  98         if (status == VERSION_PROBLEM)
  99                 fprintf(stderr,
 100                         "Perhaps iptables or your kernel needs to be upgraded.\n");
 101         exit(status);
 102 }
 103
 104 /* stolen from iptables 1.2.11
 105 They should really have them as a library so i can link to them
 106 Email them next time i remember
 107 */
 108
 109 char *
 110 addr_to_dotted(const struct in_addr *addrp)
 111 {
 112         static char buf[20];
 113         const unsigned char *bytep;
 114
 115         bytep = (const unsigned char *) &(addrp->s_addr);
 116         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 117         return buf;
 118 }
 119
 120 int string_to_number_ll(const char *s, unsigned long long min,
 121                         unsigned long long max,
 122                  unsigned long long *ret)
 123 {
 124         unsigned long long number;
 125         char *end;
 126
 127         /* Handle hex, octal, etc. */
 128         errno = 0;
 129         number = strtoull(s, &end, 0);
 130         if (*end == '\0' && end != s) {
 131                 /* we parsed a number, let's see if we want this */
 132                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 133                         *ret = number;
 134                         return 0;
 135                 }
 136         }
 137         return -1;
 138 }
 139
 140 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 141                        unsigned long *ret)
 142 {
 143         int result;
 144         unsigned long long number;
 145
 146         result = string_to_number_ll(s, min, max, &number);
 147         *ret = (unsigned long)number;
 148
 149         return result;
 150 }
 151
 152 int string_to_number(const char *s, unsigned int min, unsigned int max,
 153                 unsigned int *ret)
 154 {
 155         int result;
 156         unsigned long number;
 157
 158         result = string_to_number_l(s, min, max, &number);
 159         *ret = (unsigned int)number;
 160
 161         return result;
 162 }
 163
 164 static void free_opts(struct option *local_opts)
 165 {
 166         if (local_opts != original_opts) {
 167                 free(local_opts);
 168                 opts = original_opts;
 169                 global_option_offset = 0;
 170         }
 171 }
 172
 173 static struct option *
 174 merge_options(struct option *oldopts, const struct option *newopts,
 175               unsigned int *option_offset)
 176 {
 177         struct option *merge;
 178         unsigned int num_old, num_new, i;
 179
 180         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 181         for (num_new = 0; newopts[num_new].name; num_new++) ;
 182
 183         *option_offset = global_option_offset + OPTION_OFFSET;
 184
 185         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 186         memcpy(merge, oldopts, num_old * sizeof (struct option));
 187         for (i = 0; i < num_new; i++) {
 188                 merge[num_old + i] = newopts[i];
 189                 merge[num_old + i].val += *option_offset;
 190         }
 191         memset(merge + num_old + num_new, 0, sizeof (struct option));
 192
 193         return merge;
 194 }
 195
 196 static void *
 197 fw_calloc(size_t count, size_t size)
 198 {
 199         void *p;
 200
 201         if ((p = (void *) calloc(count, size)) == NULL) {
 202                 perror("iptables: calloc failed");
 203                 exit(1);
 204         }
 205         return p;
 206 }
 207
 208 static struct iptables_target *
 209 find_t(char *name)
 210 {
 211         struct iptables_target *m;
 212         for (m = t_list; m; m = m->next) {
 213                 if (strcmp(m->name, name) == 0)
 214                         return m;
 215         }
 216
 217         return NULL;
 218 }
 219
 220 static struct iptables_target *
 221 get_target_name(const char *name)
 222 {
 223         void *handle;
 224         char *error;
 225         char *new_name, *lname;
 226         struct iptables_target *m;
 227         char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
 228
 229 #ifdef NO_SHARED_LIBS
 230         return NULL;
 231 #endif
 232
 233         new_name = malloc(strlen(name) + 1);
 234         lname = malloc(strlen(name) + 1);
 235         if (new_name)
 236                 memset(new_name, '\0', strlen(name) + 1);
 237         else
 238                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 239
 240         if (lname)
 241                 memset(lname, '\0', strlen(name) + 1);
 242         else
 243                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 244
 245         strcpy(new_name, name);
 246         strcpy(lname, name);
 247
 248         if (isupper(lname[0])) {
 249                 int i;
 250                 for (i = 0; i < strlen(name); i++) {
 251                         lname[i] = tolower(lname[i]);
 252                 }
 253         }
 254
 255         if (islower(new_name[0])) {
 256                 int i;
 257                 for (i = 0; i < strlen(new_name); i++) {
 258                         new_name[i] = toupper(new_name[i]);
 259                 }
 260         }
 261
 262         /* try libxt_xx first */
 263         sprintf(path, "%s/libxt_%s.so", lib_dir, new_name);
 264         handle = dlopen(path, RTLD_LAZY);
 265         if (!handle) {
 266                 /* try libipt_xx next */
 267                 sprintf(path, "%s/libipt_%s.so", lib_dir, new_name);
 268                 handle = dlopen(path, RTLD_LAZY);
 269
 270                 if (!handle) {
 271                         sprintf(path, "%s/libxt_%s.so", lib_dir , lname);
 272                         handle = dlopen(path, RTLD_LAZY);
 273                 }
 274
 275                 if (!handle) {
 276                         sprintf(path, "%s/libipt_%s.so", lib_dir , lname);
 277                         handle = dlopen(path, RTLD_LAZY);
 278                 }
 279                 /* ok, lets give up .. */
 280                 if (!handle) {
 281                         fputs(dlerror(), stderr);
 282                         printf("\n");
 283                         free(new_name);
 284                         free(lname);
 285                         return NULL;
 286                 }
 287         }
 288
 289         m = dlsym(handle, new_name);
 290         if ((error = dlerror()) != NULL) {
 291                 m = (struct iptables_target *) dlsym(handle, lname);
 292                 if ((error = dlerror()) != NULL) {
 293                         m = find_t(new_name);
 294                         if (NULL == m) {
 295                                 m = find_t(lname);
 296                                 if (NULL == m) {
 297                                         fputs(error, stderr);
 298                                         fprintf(stderr, "\n");
 299                                         dlclose(handle);
 300                                         free(new_name);
 301                                         free(lname);
 302                                         return NULL;
 303                                 }
 304                         }
 305                 }
 306         }
 307
 308         free(new_name);
 309         free(lname);
 310         return m;
 311 }
 312
 313
 314 struct in_addr *dotted_to_addr(const char *dotted)
 315 {
 316         static struct in_addr addr;
 317         unsigned char *addrp;
 318         char *p, *q;
 319         unsigned int onebyte;
 320         int i;
 321         char buf[20];
 322
 323         /* copy dotted string, because we need to modify it */
 324         strncpy(buf, dotted, sizeof (buf) - 1);
 325         addrp = (unsigned char *) &(addr.s_addr);
 326
 327         p = buf;
 328         for (i = 0; i < 3; i++) {
 329                 if ((q = strchr(p, '.')) == NULL)
 330                         return (struct in_addr *) NULL;
 331
 332                 *q = '\0';
 333                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 334                         return (struct in_addr *) NULL;
 335
 336                 addrp[i] = (unsigned char) onebyte;
 337                 p = q + 1;
 338         }
 339
 340         /* we've checked 3 bytes, now we check the last one */
 341         if (string_to_number(p, 0, 255, &onebyte) == -1)
 342                 return (struct in_addr *) NULL;
 343
 344         addrp[3] = (unsigned char) onebyte;
 345
 346         return &addr;
 347 }
 348
 349 static void set_revision(char *name, u_int8_t revision)
 350 {
 351         /* Old kernel sources don't have ".revision" field,
 352         *  but we stole a byte from name. */
 353         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 354         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 355 }
 356
 357 /*
 358  * we may need to check for version mismatch
 359 */
 360 int
 361 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 362 {
 363         unsigned int nfcache = 0;
 364
 365         if (target) {
 366                 size_t size;
 367
 368                 size =
 369                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 370
 371                 if (NULL == t) {
 372                         target->t = fw_calloc(1, size);
 373                         target->t->u.target_size = size;
 374
 375                         if (target->init != NULL)
 376                                 target->init(target->t, &nfcache);
 377                         set_revision(target->t->u.user.name, target->revision);
 378                 } else {
 379                         target->t = t;
 380                 }
 381                 strcpy(target->t->u.user.name, target->name);
 382                 return 0;
 383         }
 384
 385         return -1;
 386 }
 387
 388 static int parse_ipt(struct action_util *a,int *argc_p,
 389                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 390 {
 391         struct iptables_target *m = NULL;
 392         struct ipt_entry fw;
 393         struct rtattr *tail;
 394         int c;
 395         int rargc = *argc_p;
 396         char **argv = *argv_p;
 397         int argc = 0, iargc = 0;
 398         char k[16];
 399         int size = 0;
 400         int iok = 0, ok = 0;
 401         __u32 hook = 0, index = 0;
 402
 403         lib_dir = getenv("IPTABLES_LIB_DIR");
 404         if (!lib_dir)
 405                 lib_dir = IPT_LIB_DIR;
 406
 407         {
 408                 int i;
 409                 for (i = 0; i < rargc; i++) {
 410                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 411                                 break;
 412                         }
 413                 }
 414                 iargc = argc = i;
 415         }
 416
 417         if (argc <= 2) {
 418                 fprintf(stderr,"bad arguments to ipt %d vs %d \n", argc, rargc);
 419                 return -1;
 420         }
 421
 422         while (1) {
 423                 c = getopt_long(argc, argv, "j:", opts, NULL);
 424                 if (c == -1)
 425                         break;
 426                 switch (c) {
 427                 case 'j':
 428                         m = get_target_name(optarg);
 429                         if (NULL != m) {
 430
 431                                 if (0 > build_st(m, NULL)) {
 432                                         printf(" %s error \n", m->name);
 433                                         return -1;
 434                                 }
 435                                 opts =
 436                                     merge_options(opts, m->extra_opts,
 437                                                   &m->option_offset);
 438                         } else {
 439                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 440                                 return -1;
 441                         }
 442                         ok++;
 443                         break;
 444
 445                 default:
 446                         memset(&fw, 0, sizeof (fw));
 447                         if (m) {
 448                                 m->parse(c - m->option_offset, argv, 0,
 449                                          &m->tflags, NULL, &m->t);
 450                         } else {
 451                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 452                                 return -1;
 453
 454                         }
 455                         ok++;
 456                         break;
 457
 458                 }
 459         }
 460
 461         if (iargc > optind) {
 462                 if (matches(argv[optind], "index") == 0) {
 463                         if (get_u32(&index, argv[optind + 1], 10)) {
 464                                 fprintf(stderr, "Illegal \"index\"\n");
 465                                 free_opts(opts);
 466                                 return -1;
 467                         }
 468                         iok++;
 469
 470                         optind += 2;
 471                 }
 472         }
 473
 474         if (!ok && !iok) {
 475                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 476                 return -1;
 477         }
 478
 479         /* check that we passed the correct parameters to the target */
 480         if (m)
 481                 m->final_check(m->tflags);
 482
 483         {
 484                 struct tcmsg *t = NLMSG_DATA(n);
 485                 if (t->tcm_parent != TC_H_ROOT
 486                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 487                         hook = NF_IP_PRE_ROUTING;
 488                 } else {
 489                         hook = NF_IP_POST_ROUTING;
 490                 }
 491         }
 492
 493         tail = NLMSG_TAIL(n);
 494         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 495         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 496         fprintf(stdout, "\ttarget: ");
 497
 498         if (m)
 499                 m->print(NULL, m->t, 0);
 500         fprintf(stdout, " index %d\n", index);
 501
 502         if (strlen(tname) > 16) {
 503                 size = 16;
 504                 k[15] = 0;
 505         } else {
 506                 size = 1 + strlen(tname);
 507         }
 508         strncpy(k, tname, size);
 509
 510         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 511         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 512         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 513         if (m)
 514                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 515         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 516
 517         argc -= optind;
 518         argv += optind;
 519         *argc_p = rargc - iargc;
 520         *argv_p = argv;
 521
 522         optind = 0;
 523         free_opts(opts);
 524         /* Clear flags if target will be used again */
 525         m->tflags=0;
 526         m->used=0;
 527         /* Free allocated memory */
 528         if (m->t)
 529             free(m->t);
 530
 531
 532         return 0;
 533
 534 }
 535
 536 static int
 537 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 538 {
 539         struct rtattr *tb[TCA_IPT_MAX + 1];
 540         struct ipt_entry_target *t = NULL;
 541
 542         if (arg == NULL)
 543                 return -1;
 544
 545         lib_dir = getenv("IPTABLES_LIB_DIR");
 546         if (!lib_dir)
 547                 lib_dir = IPT_LIB_DIR;
 548
 549         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 550
 551         if (tb[TCA_IPT_TABLE] == NULL) {
 552                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 553         } else {
 554                 fprintf(f, "tablename: %s ",
 555                         rta_getattr_str(tb[TCA_IPT_TABLE]));
 556         }
 557
 558         if (tb[TCA_IPT_HOOK] == NULL) {
 559                 fprintf(f, "[NULL ipt hook name ]\n ");
 560                 return -1;
 561         } else {
 562                 __u32 hook;
 563                 hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);
 564                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 565         }
 566
 567         if (tb[TCA_IPT_TARG] == NULL) {
 568                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 569                 return -1;
 570         } else {
 571                 struct iptables_target *m = NULL;
 572                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 573                 m = get_target_name(t->u.user.name);
 574                 if (NULL != m) {
 575                         if (0 > build_st(m, t)) {
 576                                 fprintf(stderr, " %s error \n", m->name);
 577                                 return -1;
 578                         }
 579
 580                         opts =
 581                             merge_options(opts, m->extra_opts,
 582                                           &m->option_offset);
 583                 } else {
 584                         fprintf(stderr, " failed to find target %s\n\n",
 585                                 t->u.user.name);
 586                         return -1;
 587                 }
 588                 fprintf(f, "\ttarget ");
 589                 m->print(NULL, m->t, 0);
 590                 if (tb[TCA_IPT_INDEX] == NULL) {
 591                         fprintf(f, " [NULL ipt target index ]\n");
 592                 } else {
 593                         __u32 index;
 594                         index = rta_getattr_u32(tb[TCA_IPT_INDEX]);
 595                         fprintf(f, " \n\tindex %d", index);
 596                 }
 597
 598                 if (tb[TCA_IPT_CNT]) {
 599                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 600                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 601                 }
 602                 if (show_stats) {
 603                         if (tb[TCA_IPT_TM]) {
 604                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 605                                 print_tm(f,tm);
 606                         }
 607                 }
 608                 fprintf(f, " \n");
 609
 610         }
 611         free_opts(opts);
 612
 613         return 0;
 614 }
 615
 616 struct action_util ipt_action_util = {
 617         .id = "ipt",
 618         .parse_aopt = parse_ipt,
 619         .print_aopt = print_ipt,
 620 };