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 <sys/socket.h>
  14 #include <netinet/in.h>
  15 #include <arpa/inet.h>
  16 #include <iptables.h>
  17 #include <linux/netfilter.h>
  18 #include <linux/netfilter_ipv4/ip_tables.h>
  19 #include "utils.h"
  20 #include "tc_util.h"
  21 #include <linux/tc_act/tc_ipt.h>
  22 #include <stdio.h>
  23 #include <dlfcn.h>
  24 #include <getopt.h>
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <netdb.h>
  28 #include <stdlib.h>
  29 #include <ctype.h>
  30 #include <stdarg.h>
  31 #include <unistd.h>
  32 #include <fcntl.h>
  33 #include <sys/wait.h>
  34
  35 static const char *pname = "tc-ipt";
  36 static const char *tname = "mangle";
  37 static const char *pversion = "0.1";
  38
  39 static const char *ipthooks[] = {
  40         "NF_IP_PRE_ROUTING",
  41         "NF_IP_LOCAL_IN",
  42         "NF_IP_FORWARD",
  43         "NF_IP_LOCAL_OUT",
  44         "NF_IP_POST_ROUTING",
  45 };
  46
  47 static struct option original_opts[] = {
  48         {"jump", 1, 0, 'j'},
  49         {0, 0, 0, 0}
  50 };
  51
  52 static struct xtables_target *t_list;
  53 static struct option *opts = original_opts;
  54 static unsigned int global_option_offset;
  55 #define OPTION_OFFSET 256
  56
  57 char *lib_dir;
  58
  59 void
  60 xtables_register_target(struct xtables_target *me)
  61 {
  62         me->next = t_list;
  63         t_list = me;
  64
  65 }
  66
  67 static void exit_tryhelp(int status)
  68 {
  69         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  70                 pname, pname);
  71         exit(status);
  72 }
  73
  74 static void exit_error(enum xtables_exittype status, char *msg, ...)
  75 {
  76         va_list args;
  77
  78         va_start(args, msg);
  79         fprintf(stderr, "%s v%s: ", pname, pversion);
  80         vfprintf(stderr, msg, args);
  81         va_end(args);
  82         fprintf(stderr, "\n");
  83         if (status == PARAMETER_PROBLEM)
  84                 exit_tryhelp(status);
  85         if (status == VERSION_PROBLEM)
  86                 fprintf(stderr,
  87                         "Perhaps iptables or your kernel needs to be upgraded.\n");
  88         exit(status);
  89 }
  90
  91 /* stolen from iptables 1.2.11
  92 They should really have them as a library so i can link to them
  93 Email them next time i remember
  94 */
  95
  96 static void free_opts(struct option *local_opts)
  97 {
  98         if (local_opts != original_opts) {
  99                 free(local_opts);
 100                 opts = original_opts;
 101                 global_option_offset = 0;
 102         }
 103 }
 104
 105 static struct option *
 106 merge_options(struct option *oldopts, const struct option *newopts,
 107               unsigned int *option_offset)
 108 {
 109         struct option *merge;
 110         unsigned int num_old, num_new, i;
 111
 112         for (num_old = 0; oldopts[num_old].name; num_old++);
 113         for (num_new = 0; newopts[num_new].name; num_new++);
 114
 115         *option_offset = global_option_offset + OPTION_OFFSET;
 116
 117         merge = malloc(sizeof(struct option) * (num_new + num_old + 1));
 118         memcpy(merge, oldopts, num_old * sizeof(struct option));
 119         for (i = 0; i < num_new; i++) {
 120                 merge[num_old + i] = newopts[i];
 121                 merge[num_old + i].val += *option_offset;
 122         }
 123         memset(merge + num_old + num_new, 0, sizeof(struct option));
 124
 125         return merge;
 126 }
 127
 128 static void *
 129 fw_calloc(size_t count, size_t size)
 130 {
 131         void *p;
 132
 133         if ((p = (void *) calloc(count, size)) == NULL) {
 134                 perror("iptables: calloc failed");
 135                 exit(1);
 136         }
 137         return p;
 138 }
 139
 140 static struct xtables_target *
 141 find_t(char *name)
 142 {
 143         struct xtables_target *m;
 144
 145         for (m = t_list; m; m = m->next) {
 146                 if (strcmp(m->name, name) == 0)
 147                         return m;
 148         }
 149
 150         return NULL;
 151 }
 152
 153 static struct xtables_target *
 154 get_target_name(const char *name)
 155 {
 156         void *handle;
 157         char *error;
 158         char *new_name, *lname;
 159         struct xtables_target *m;
 160         char path[strlen(lib_dir) + sizeof("/libipt_.so") + strlen(name)];
 161
 162 #ifdef NO_SHARED_LIBS
 163         return NULL;
 164 #endif
 165
 166         new_name = calloc(1, strlen(name) + 1);
 167         lname = calloc(1, strlen(name) + 1);
 168         if (!new_name)
 169                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 170         if (!lname)
 171                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 172
 173         strcpy(new_name, name);
 174         strcpy(lname, name);
 175
 176         if (isupper(lname[0])) {
 177                 int i;
 178
 179                 for (i = 0; i < strlen(name); i++) {
 180                         lname[i] = tolower(lname[i]);
 181                 }
 182         }
 183
 184         if (islower(new_name[0])) {
 185                 int i;
 186
 187                 for (i = 0; i < strlen(new_name); i++) {
 188                         new_name[i] = toupper(new_name[i]);
 189                 }
 190         }
 191
 192         /* try libxt_xx first */
 193         sprintf(path, "%s/libxt_%s.so", lib_dir, new_name);
 194         handle = dlopen(path, RTLD_LAZY);
 195         if (!handle) {
 196                 /* try libipt_xx next */
 197                 sprintf(path, "%s/libipt_%s.so", lib_dir, new_name);
 198                 handle = dlopen(path, RTLD_LAZY);
 199
 200                 if (!handle) {
 201                         sprintf(path, "%s/libxt_%s.so", lib_dir, lname);
 202                         handle = dlopen(path, RTLD_LAZY);
 203                 }
 204
 205                 if (!handle) {
 206                         sprintf(path, "%s/libipt_%s.so", lib_dir, lname);
 207                         handle = dlopen(path, RTLD_LAZY);
 208                 }
 209                 /* ok, lets give up .. */
 210                 if (!handle) {
 211                         fputs(dlerror(), stderr);
 212                         printf("\n");
 213                         free(new_name);
 214                         free(lname);
 215                         return NULL;
 216                 }
 217         }
 218
 219         m = dlsym(handle, new_name);
 220         if ((error = dlerror()) != NULL) {
 221                 m = (struct xtables_target *) dlsym(handle, lname);
 222                 if ((error = dlerror()) != NULL) {
 223                         m = find_t(new_name);
 224                         if (m == NULL) {
 225                                 m = find_t(lname);
 226                                 if (m == NULL) {
 227                                         fputs(error, stderr);
 228                                         fprintf(stderr, "\n");
 229                                         dlclose(handle);
 230                                         free(new_name);
 231                                         free(lname);
 232                                         return NULL;
 233                                 }
 234                         }
 235                 }
 236         }
 237
 238         free(new_name);
 239         free(lname);
 240         return m;
 241 }
 242
 243 static void set_revision(char *name, u_int8_t revision)
 244 {
 245         /* Old kernel sources don't have ".revision" field,
 246         *  but we stole a byte from name. */
 247         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 248         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 249 }
 250
 251 /*
 252  * we may need to check for version mismatch
 253 */
 254 static int build_st(struct xtables_target *target, struct ipt_entry_target *t)
 255 {
 256         if (target) {
 257                 size_t size;
 258
 259                 size =
 260                     XT_ALIGN(sizeof(struct ipt_entry_target)) + target->size;
 261
 262                 if (t == NULL) {
 263                         target->t = fw_calloc(1, size);
 264                         target->t->u.target_size = size;
 265
 266                         if (target->init != NULL)
 267                                 target->init(target->t);
 268                         set_revision(target->t->u.user.name, target->revision);
 269                 } else {
 270                         target->t = t;
 271                 }
 272                 strcpy(target->t->u.user.name, target->name);
 273                 return 0;
 274         }
 275
 276         return -1;
 277 }
 278
 279 static int parse_ipt(struct action_util *a, int *argc_p,
 280                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 281 {
 282         struct xtables_target *m = NULL;
 283         struct ipt_entry fw;
 284         struct rtattr *tail;
 285         int c;
 286         int rargc = *argc_p;
 287         char **argv = *argv_p;
 288         int argc = 0, iargc = 0;
 289         char k[FILTER_NAMESZ];
 290         int size = 0;
 291         int iok = 0, ok = 0;
 292         __u32 hook = 0, index = 0;
 293
 294         lib_dir = getenv("IPTABLES_LIB_DIR");
 295         if (!lib_dir)
 296                 lib_dir = IPT_LIB_DIR;
 297
 298         {
 299                 int i;
 300
 301                 for (i = 0; i < rargc; i++) {
 302                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 303                                 break;
 304                         }
 305                 }
 306                 iargc = argc = i;
 307         }
 308
 309         if (argc <= 2) {
 310                 fprintf(stderr, "bad arguments to ipt %d vs %d\n", argc, rargc);
 311                 return -1;
 312         }
 313
 314         while (1) {
 315                 c = getopt_long(argc, argv, "j:", opts, NULL);
 316                 if (c == -1)
 317                         break;
 318                 switch (c) {
 319                 case 'j':
 320                         m = get_target_name(optarg);
 321                         if (m != NULL) {
 322
 323                                 if (build_st(m, NULL) < 0) {
 324                                         printf(" %s error\n", m->name);
 325                                         return -1;
 326                                 }
 327                                 opts =
 328                                     merge_options(opts, m->extra_opts,
 329                                                   &m->option_offset);
 330                         } else {
 331                                 fprintf(stderr, " failed to find target %s\n\n", optarg);
 332                                 return -1;
 333                         }
 334                         ok++;
 335                         break;
 336
 337                 default:
 338                         memset(&fw, 0, sizeof(fw));
 339                         if (m) {
 340                                 m->parse(c - m->option_offset, argv, 0,
 341                                          &m->tflags, NULL, &m->t);
 342                         } else {
 343                                 fprintf(stderr, " failed to find target %s\n\n", optarg);
 344                                 return -1;
 345
 346                         }
 347                         ok++;
 348                         break;
 349
 350                 }
 351         }
 352
 353         if (iargc > optind) {
 354                 if (matches(argv[optind], "index") == 0) {
 355                         if (get_u32(&index, argv[optind + 1], 10)) {
 356                                 fprintf(stderr, "Illegal \"index\"\n");
 357                                 free_opts(opts);
 358                                 return -1;
 359                         }
 360                         iok++;
 361
 362                         optind += 2;
 363                 }
 364         }
 365
 366         if (!ok && !iok) {
 367                 fprintf(stderr, " ipt Parser BAD!! (%s)\n", *argv);
 368                 return -1;
 369         }
 370
 371         /* check that we passed the correct parameters to the target */
 372         if (m)
 373                 m->final_check(m->tflags);
 374
 375         {
 376                 struct tcmsg *t = NLMSG_DATA(n);
 377
 378                 if (t->tcm_parent != TC_H_ROOT
 379                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 380                         hook = NF_IP_PRE_ROUTING;
 381                 } else {
 382                         hook = NF_IP_POST_ROUTING;
 383                 }
 384         }
 385
 386         tail = addattr_nest(n, MAX_MSG, tca_id);
 387         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 388         fprintf(stdout, "\ttarget: ");
 389
 390         if (m)
 391                 m->print(NULL, m->t, 0);
 392         fprintf(stdout, " index %d\n", index);
 393
 394         if (strlen(tname) > 16) {
 395                 size = 16;
 396                 k[15] = 0;
 397         } else {
 398                 size = 1 + strlen(tname);
 399         }
 400         strncpy(k, tname, size);
 401
 402         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 403         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 404         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 405         if (m)
 406                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 407         addattr_nest_end(n, tail);
 408
 409         argc -= optind;
 410         argv += optind;
 411         *argc_p = rargc - iargc;
 412         *argv_p = argv;
 413
 414         optind = 0;
 415         free_opts(opts);
 416         /* Clear flags if target will be used again */
 417         m->tflags = 0;
 418         m->used = 0;
 419         /* Free allocated memory */
 420         if (m->t)
 421             free(m->t);
 422
 423
 424         return 0;
 425
 426 }
 427
 428 static int
 429 print_ipt(struct action_util *au, FILE * f, struct rtattr *arg)
 430 {
 431         struct rtattr *tb[TCA_IPT_MAX + 1];
 432         struct ipt_entry_target *t = NULL;
 433
 434         if (arg == NULL)
 435                 return -1;
 436
 437         lib_dir = getenv("IPTABLES_LIB_DIR");
 438         if (!lib_dir)
 439                 lib_dir = IPT_LIB_DIR;
 440
 441         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 442
 443         if (tb[TCA_IPT_TABLE] == NULL) {
 444                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 445         } else {
 446                 fprintf(f, "tablename: %s ",
 447                         rta_getattr_str(tb[TCA_IPT_TABLE]));
 448         }
 449
 450         if (tb[TCA_IPT_HOOK] == NULL) {
 451                 fprintf(f, "[NULL ipt hook name ]\n ");
 452                 return -1;
 453         } else {
 454                 __u32 hook;
 455
 456                 hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);
 457                 fprintf(f, " hook: %s\n", ipthooks[hook]);
 458         }
 459
 460         if (tb[TCA_IPT_TARG] == NULL) {
 461                 fprintf(f, "\t[NULL ipt target parameters ]\n");
 462                 return -1;
 463         } else {
 464                 struct xtables_target *m = NULL;
 465
 466                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 467                 m = get_target_name(t->u.user.name);
 468                 if (m != NULL) {
 469                         if (build_st(m, t) < 0) {
 470                                 fprintf(stderr, " %s error\n", m->name);
 471                                 return -1;
 472                         }
 473
 474                         opts =
 475                             merge_options(opts, m->extra_opts,
 476                                           &m->option_offset);
 477                 } else {
 478                         fprintf(stderr, " failed to find target %s\n\n",
 479                                 t->u.user.name);
 480                         return -1;
 481                 }
 482                 fprintf(f, "\ttarget ");
 483                 m->print(NULL, m->t, 0);
 484                 if (tb[TCA_IPT_INDEX] == NULL) {
 485                         fprintf(f, " [NULL ipt target index ]\n");
 486                 } else {
 487                         __u32 index;
 488
 489                         index = rta_getattr_u32(tb[TCA_IPT_INDEX]);
 490                         fprintf(f, "\n\tindex %u", index);
 491                 }
 492
 493                 if (tb[TCA_IPT_CNT]) {
 494                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);
 495
 496                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 497                 }
 498                 if (show_stats) {
 499                         if (tb[TCA_IPT_TM]) {
 500                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 501
 502                                 print_tm(f, tm);
 503                         }
 504                 }
 505                 fprintf(f, "\n");
 506
 507         }
 508         free_opts(opts);
 509
 510         return 0;
 511 }
 512
 513 struct action_util ipt_action_util = {
 514         .id = "ipt",
 515         .parse_aopt = parse_ipt,
 516         .print_aopt = print_ipt,
 517 };