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_ipv4/ip_tables.h>
  20 #include "utils.h"
  21 #include "tc_util.h"
  22 #include <linux/tc_act/tc_ipt.h>
  23 #include <stdio.h>
  24 #include <dlfcn.h>
  25 #include <getopt.h>
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <netdb.h>
  29 #include <stdlib.h>
  30 #include <ctype.h>
  31 #include <stdarg.h>
  32 #include <limits.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 exit_tryhelp(int status)
  73 {
  74         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  75                 pname, pname);
  76         exit(status);
  77 }
  78
  79 void
  80 exit_error(enum exittype status, char *msg, ...)
  81 {
  82         va_list args;
  83
  84         va_start(args, msg);
  85         fprintf(stderr, "%s v%s: ", pname, pversion);
  86         vfprintf(stderr, msg, args);
  87         va_end(args);
  88         fprintf(stderr, "\n");
  89         if (status == PARAMETER_PROBLEM)
  90                 exit_tryhelp(status);
  91         if (status == VERSION_PROBLEM)
  92                 fprintf(stderr,
  93                         "Perhaps iptables or your kernel needs to be upgraded.\n");
  94         exit(status);
  95 }
  96
  97 /* stolen from iptables 1.2.11
  98 They should really have them as a library so i can link to them
  99 Email them next time i remember
 100 */
 101
 102 char *
 103 addr_to_dotted(const struct in_addr *addrp)
 104 {
 105         static char buf[20];
 106         const unsigned char *bytep;
 107
 108         bytep = (const unsigned char *) &(addrp->s_addr);
 109         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 110         return buf;
 111 }
 112
 113 int string_to_number_ll(const char *s, unsigned long long min,
 114                         unsigned long long max,
 115                  unsigned long long *ret)
 116 {
 117         unsigned long long number;
 118         char *end;
 119
 120         /* Handle hex, octal, etc. */
 121         errno = 0;
 122         number = strtoull(s, &end, 0);
 123         if (*end == '\0' && end != s) {
 124                 /* we parsed a number, let's see if we want this */
 125                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 126                         *ret = number;
 127                         return 0;
 128                 }
 129         }
 130         return -1;
 131 }
 132
 133 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 134                        unsigned long *ret)
 135 {
 136         int result;
 137         unsigned long long number;
 138
 139         result = string_to_number_ll(s, min, max, &number);
 140         *ret = (unsigned long)number;
 141
 142         return result;
 143 }
 144
 145 int string_to_number(const char *s, unsigned int min, unsigned int max,
 146                 unsigned int *ret)
 147 {
 148         int result;
 149         unsigned long number;
 150
 151         result = string_to_number_l(s, min, max, &number);
 152         *ret = (unsigned int)number;
 153
 154         return result;
 155 }
 156
 157 static void free_opts(struct option *opts)
 158 {
 159         if (opts != original_opts) {
 160                 free(opts);
 161                 opts = original_opts;
 162                 global_option_offset = 0;
 163         }
 164 }
 165
 166 static struct option *
 167 merge_options(struct option *oldopts, const struct option *newopts,
 168               unsigned int *option_offset)
 169 {
 170         struct option *merge;
 171         unsigned int num_old, num_new, i;
 172
 173         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 174         for (num_new = 0; newopts[num_new].name; num_new++) ;
 175
 176         *option_offset = global_option_offset + OPTION_OFFSET;
 177
 178         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 179         memcpy(merge, oldopts, num_old * sizeof (struct option));
 180         for (i = 0; i < num_new; i++) {
 181                 merge[num_old + i] = newopts[i];
 182                 merge[num_old + i].val += *option_offset;
 183         }
 184         memset(merge + num_old + num_new, 0, sizeof (struct option));
 185
 186         return merge;
 187 }
 188
 189 static void *
 190 fw_calloc(size_t count, size_t size)
 191 {
 192         void *p;
 193
 194         if ((p = (void *) calloc(count, size)) == NULL) {
 195                 perror("iptables: calloc failed");
 196                 exit(1);
 197         }
 198         return p;
 199 }
 200
 201 static struct iptables_target *
 202 find_t(char *name)
 203 {
 204         struct iptables_target *m;
 205         for (m = t_list; m; m = m->next) {
 206                 if (strcmp(m->name, name) == 0)
 207                         return m;
 208         }
 209
 210         return NULL;
 211 }
 212
 213 static struct iptables_target *
 214 get_target_name(const char *name)
 215 {
 216         void *handle;
 217         char *error;
 218         char *new_name, *lname;
 219         struct iptables_target *m;
 220         char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
 221
 222         new_name = malloc(strlen(name) + 1);
 223         lname = malloc(strlen(name) + 1);
 224         if (new_name)
 225                 memset(new_name, '\0', strlen(name) + 1);
 226         else
 227                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 228
 229         if (lname)
 230                 memset(lname, '\0', strlen(name) + 1);
 231         else
 232                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 233
 234         strcpy(new_name, name);
 235         strcpy(lname, name);
 236
 237         if (isupper(lname[0])) {
 238                 int i;
 239                 for (i = 0; i < strlen(name); i++) {
 240                         lname[i] = tolower(lname[i]);
 241                 }
 242         }
 243
 244         if (islower(new_name[0])) {
 245                 int i;
 246                 for (i = 0; i < strlen(new_name); i++) {
 247                         new_name[i] = toupper(new_name[i]);
 248                 }
 249         }
 250
 251         sprintf(path,  "%s/libipt_%s.so",lib_dir, new_name);
 252         handle = dlopen(path, RTLD_LAZY);
 253         if (!handle) {
 254                 sprintf(path, lib_dir, "/libipt_%s.so", lname);
 255                 handle = dlopen(path, RTLD_LAZY);
 256                 if (!handle) {
 257                         fputs(dlerror(), stderr);
 258                         printf("\n");
 259                         return NULL;
 260                 }
 261         }
 262
 263         m = dlsym(handle, new_name);
 264         if ((error = dlerror()) != NULL) {
 265                 m = (struct iptables_target *) dlsym(handle, lname);
 266                 if ((error = dlerror()) != NULL) {
 267                         m = find_t(new_name);
 268                         if (NULL == m) {
 269                                 m = find_t(lname);
 270                                 if (NULL == m) {
 271                                         fputs(error, stderr);
 272                                         fprintf(stderr, "\n");
 273                                         dlclose(handle);
 274                                         return NULL;
 275                                 }
 276                         }
 277                 }
 278         }
 279
 280         return m;
 281 }
 282
 283
 284 struct in_addr *dotted_to_addr(const char *dotted)
 285 {
 286         static struct in_addr addr;
 287         unsigned char *addrp;
 288         char *p, *q;
 289         unsigned int onebyte;
 290         int i;
 291         char buf[20];
 292
 293         /* copy dotted string, because we need to modify it */
 294         strncpy(buf, dotted, sizeof (buf) - 1);
 295         addrp = (unsigned char *) &(addr.s_addr);
 296
 297         p = buf;
 298         for (i = 0; i < 3; i++) {
 299                 if ((q = strchr(p, '.')) == NULL)
 300                         return (struct in_addr *) NULL;
 301
 302                 *q = '\0';
 303                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 304                         return (struct in_addr *) NULL;
 305
 306                 addrp[i] = (unsigned char) onebyte;
 307                 p = q + 1;
 308         }
 309
 310         /* we've checked 3 bytes, now we check the last one */
 311         if (string_to_number(p, 0, 255, &onebyte) == -1)
 312                 return (struct in_addr *) NULL;
 313
 314         addrp[3] = (unsigned char) onebyte;
 315
 316         return &addr;
 317 }
 318
 319 static void set_revision(char *name, u_int8_t revision)
 320 {
 321         /* Old kernel sources don't have ".revision" field,
 322         *  but we stole a byte from name. */
 323         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 324         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 325 }
 326
 327 /*
 328  * we may need to check for version mismatch
 329 */
 330 int
 331 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 332 {
 333         unsigned int nfcache = 0;
 334
 335         if (target) {
 336                 size_t size;
 337
 338                 size =
 339                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 340
 341                 if (NULL == t) {
 342                         target->t = fw_calloc(1, size);
 343                         target->t->u.target_size = size;
 344
 345                         if (target->init != NULL)
 346                                 target->init(target->t, &nfcache);
 347                         set_revision(target->t->u.user.name, target->revision);
 348                 } else {
 349                         target->t = t;
 350                 }
 351                 strcpy(target->t->u.user.name, target->name);
 352                 return 0;
 353         }
 354
 355         return -1;
 356 }
 357
 358 static int parse_ipt(struct action_util *a,int *argc_p,
 359                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 360 {
 361         struct iptables_target *m = NULL;
 362         struct ipt_entry fw;
 363         struct rtattr *tail;
 364         int c;
 365         int rargc = *argc_p;
 366         char **argv = *argv_p;
 367         int argc = 0, iargc = 0;
 368         char k[16];
 369         int res = -1;
 370         int size = 0;
 371         int iok = 0, ok = 0;
 372         __u32 hook = 0, index = 0;
 373         res = 0;
 374
 375         lib_dir = getenv("IPTABLES_LIB_DIR");
 376         if (!lib_dir)
 377                 lib_dir = IPT_LIB_DIR;
 378
 379         {
 380                 int i;
 381                 for (i = 0; i < rargc; i++) {
 382                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 383                                 break;
 384                         }
 385                 }
 386                 iargc = argc = i;
 387         }
 388
 389         if (argc <= 2) {
 390                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 391                 return -1;
 392         }
 393
 394         while (1) {
 395                 c = getopt_long(argc, argv, "j:", opts, NULL);
 396                 if (c == -1)
 397                         break;
 398                 switch (c) {
 399                 case 'j':
 400                         m = get_target_name(optarg);
 401                         if (NULL != m) {
 402
 403                                 if (0 > build_st(m, NULL)) {
 404                                         printf(" %s error \n", m->name);
 405                                         return -1;
 406                                 }
 407                                 opts =
 408                                     merge_options(opts, m->extra_opts,
 409                                                   &m->option_offset);
 410                         } else {
 411                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 412                                 return -1;
 413                         }
 414                         ok++;
 415                         break;
 416
 417                 default:
 418                         memset(&fw, 0, sizeof (fw));
 419                         if (m) {
 420                                 m->parse(c - m->option_offset, argv, 0,
 421                                          &m->tflags, NULL, &m->t);
 422                         } else {
 423                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 424                                 return -1;
 425
 426                         }
 427                         ok++;
 428                         break;
 429
 430                 }
 431         }
 432
 433         if (iargc > optind) {
 434                 if (matches(argv[optind], "index") == 0) {
 435                         if (get_u32(&index, argv[optind + 1], 10)) {
 436                                 fprintf(stderr, "Illegal \"index\"\n");
 437                                 free_opts(opts);
 438                                 return -1;
 439                         }
 440                         iok++;
 441
 442                         optind += 2;
 443                 }
 444         }
 445
 446         if (!ok && !iok) {
 447                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 448                 return -1;
 449         }
 450
 451         /* check that we passed the correct parameters to the target */
 452         if (m)
 453                 m->final_check(m->tflags);
 454
 455         {
 456                 struct tcmsg *t = NLMSG_DATA(n);
 457                 if (t->tcm_parent != TC_H_ROOT
 458                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 459                         hook = NF_IP_PRE_ROUTING;
 460                 } else {
 461                         hook = NF_IP_POST_ROUTING;
 462                 }
 463         }
 464
 465         tail = NLMSG_TAIL(n);
 466         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 467         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 468         fprintf(stdout, "\ttarget: ");
 469
 470         if (m)
 471                 m->print(NULL, m->t, 0);
 472         fprintf(stdout, " index %d\n", index);
 473
 474         if (strlen(tname) > 16) {
 475                 size = 16;
 476                 k[15] = 0;
 477         } else {
 478                 size = 1 + strlen(tname);
 479         }
 480         strncpy(k, tname, size);
 481
 482         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 483         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 484         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 485         if (m)
 486                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 487         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 488
 489         argc -= optind;
 490         argv += optind;
 491         *argc_p = rargc - iargc;
 492         *argv_p = argv;
 493
 494         optind = 1;
 495         free_opts(opts);
 496
 497         return 0;
 498
 499 }
 500
 501 static int
 502 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 503 {
 504         struct rtattr *tb[TCA_IPT_MAX + 1];
 505         struct ipt_entry_target *t = NULL;
 506
 507         if (arg == NULL)
 508                 return -1;
 509
 510         lib_dir = getenv("IPTABLES_LIB_DIR");
 511         if (!lib_dir)
 512                 lib_dir = IPT_LIB_DIR;
 513
 514         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 515
 516         if (tb[TCA_IPT_TABLE] == NULL) {
 517                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 518         } else {
 519                 fprintf(f, "tablename: %s ",
 520                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 521         }
 522
 523         if (tb[TCA_IPT_HOOK] == NULL) {
 524                 fprintf(f, "[NULL ipt hook name ]\n ");
 525                 return -1;
 526         } else {
 527                 __u32 hook;
 528                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 529                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 530         }
 531
 532         if (tb[TCA_IPT_TARG] == NULL) {
 533                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 534                 return -1;
 535         } else {
 536                 struct iptables_target *m = NULL;
 537                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 538                 m = get_target_name(t->u.user.name);
 539                 if (NULL != m) {
 540                         if (0 > build_st(m, t)) {
 541                                 fprintf(stderr, " %s error \n", m->name);
 542                                 return -1;
 543                         }
 544
 545                         opts =
 546                             merge_options(opts, m->extra_opts,
 547                                           &m->option_offset);
 548                 } else {
 549                         fprintf(stderr, " failed to find target %s\n\n",
 550                                 t->u.user.name);
 551                         return -1;
 552                 }
 553                 fprintf(f, "\ttarget ");
 554                 m->print(NULL, m->t, 0);
 555                 if (tb[TCA_IPT_INDEX] == NULL) {
 556                         fprintf(f, " [NULL ipt target index ]\n");
 557                 } else {
 558                         __u32 index;
 559                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 560                         fprintf(f, " \n\tindex %d", index);
 561                 }
 562
 563                 if (tb[TCA_IPT_CNT]) {
 564                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 565                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 566                 }
 567                 if (show_stats) {
 568                         if (tb[TCA_IPT_TM]) {
 569                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 570                                 print_tm(f,tm);
 571                         }
 572                 }
 573                 fprintf(f, " \n");
 574
 575         }
 576         free_opts(opts);
 577
 578         return 0;
 579 }
 580
 581 struct action_util ipt_action_util = {
 582         .id = "ipt",
 583         .parse_aopt = parse_ipt,
 584         .print_aopt = print_ipt,
 585 };
 586