tc/m_xt.c

   1 /*
   2  * m_xt.c       xtables 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 <net/if.h>
  17 #include <limits.h>
  18 #include <linux/netfilter.h>
  19 #include <linux/netfilter_ipv4/ip_tables.h>
  20 #include <xtables.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 #ifndef XT_LIB_DIR
  37 #       define XT_LIB_DIR "/lib/xtables"
  38 #endif
  39
  40 #ifndef __ALIGN_KERNEL
  41 #define __ALIGN_KERNEL(x, a)    \
  42         __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
  43 #define __ALIGN_KERNEL_MASK(x, mask) \
  44         (((x) + (mask)) & ~(mask))
  45 #endif
  46
  47 #ifndef ALIGN
  48 #define ALIGN(x, a)     __ALIGN_KERNEL((x), (a))
  49 #endif
  50
  51 static const char *tname = "mangle";
  52
  53 char *lib_dir;
  54
  55 static const char * const ipthooks[] = {
  56         "NF_IP_PRE_ROUTING",
  57         "NF_IP_LOCAL_IN",
  58         "NF_IP_FORWARD",
  59         "NF_IP_LOCAL_OUT",
  60         "NF_IP_POST_ROUTING",
  61 };
  62
  63 static struct option original_opts[] = {
  64         {
  65                 .name = "jump",
  66                 .has_arg = 1,
  67                 .val = 'j'
  68         },
  69         {0, 0, 0, 0}
  70 };
  71
  72 static struct xtables_globals tcipt_globals = {
  73         .option_offset = 0,
  74         .program_name = "tc-ipt",
  75         .program_version = "0.2",
  76         .orig_opts = original_opts,
  77         .opts = original_opts,
  78         .exit_err = NULL,
  79 #if XTABLES_VERSION_CODE >= 11
  80         .compat_rev = xtables_compatible_revision,
  81 #endif
  82 };
  83
  84 /*
  85  * we may need to check for version mismatch
  86 */
  87 static int
  88 build_st(struct xtables_target *target, struct xt_entry_target *t)
  89 {
  90
  91         size_t size =
  92                     XT_ALIGN(sizeof(struct xt_entry_target)) + target->size;
  93
  94         if (t == NULL) {
  95                 target->t = xtables_calloc(1, size);
  96                 target->t->u.target_size = size;
  97                 strncpy(target->t->u.user.name, target->name,
  98                         sizeof(target->t->u.user.name) - 1);
  99                 target->t->u.user.revision = target->revision;
 100
 101                 if (target->init != NULL)
 102                         target->init(target->t);
 103         } else {
 104                 target->t = t;
 105         }
 106         return 0;
 107
 108 }
 109
 110 static void set_lib_dir(void)
 111 {
 112
 113         lib_dir = getenv("XTABLES_LIBDIR");
 114         if (!lib_dir) {
 115                 lib_dir = getenv("IPTABLES_LIB_DIR");
 116                 if (lib_dir)
 117                         fprintf(stderr, "using deprecated IPTABLES_LIB_DIR\n");
 118         }
 119         if (lib_dir == NULL)
 120                 lib_dir = XT_LIB_DIR;
 121
 122 }
 123
 124 static int get_xtables_target_opts(struct xtables_globals *globals,
 125                                    struct xtables_target *m)
 126 {
 127         struct option *opts;
 128
 129 #if XTABLES_VERSION_CODE >= 6
 130         opts = xtables_options_xfrm(globals->orig_opts,
 131                                     globals->opts,
 132                                     m->x6_options,
 133                                     &m->option_offset);
 134 #else
 135         opts = xtables_merge_options(globals->opts,
 136                                      m->extra_opts,
 137                                      &m->option_offset);
 138 #endif
 139         if (!opts)
 140                 return -1;
 141         globals->opts = opts;
 142         return 0;
 143 }
 144
 145 static int parse_ipt(struct action_util *a, int *argc_p,
 146                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 147 {
 148         struct xtables_target *m = NULL;
 149 #if XTABLES_VERSION_CODE >= 6
 150         struct ipt_entry fw = {};
 151 #endif
 152         struct rtattr *tail;
 153
 154         int c;
 155         char **argv = *argv_p;
 156         int argc;
 157         char k[FILTER_NAMESZ];
 158         int size = 0;
 159         int iok = 0, ok = 0;
 160         __u32 hook = 0, index = 0;
 161
 162         /* copy tcipt_globals because .opts will be modified by iptables */
 163         struct xtables_globals tmp_tcipt_globals = tcipt_globals;
 164
 165         xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
 166         set_lib_dir();
 167
 168         /* parse only up until the next action */
 169         for (argc = 0; argc < *argc_p; argc++) {
 170                 if (!argv[argc] || !strcmp(argv[argc], "action"))
 171                         break;
 172         }
 173
 174         if (argc <= 2) {
 175                 fprintf(stderr,
 176                         "too few arguments for xt, need at least '-j <target>'\n");
 177                 return -1;
 178         }
 179
 180         while (1) {
 181                 c = getopt_long(argc, argv, "j:", tmp_tcipt_globals.opts, NULL);
 182                 if (c == -1)
 183                         break;
 184                 switch (c) {
 185                 case 'j':
 186                         m = xtables_find_target(optarg, XTF_TRY_LOAD);
 187                         if (!m) {
 188                                 fprintf(stderr,
 189                                         " failed to find target %s\n\n",
 190                                         optarg);
 191                                 return -1;
 192                         }
 193
 194                         if (build_st(m, NULL) < 0) {
 195                                 printf(" %s error\n", m->name);
 196                                 return -1;
 197                         }
 198
 199                         if (get_xtables_target_opts(&tmp_tcipt_globals,
 200                                                     m) < 0) {
 201                                 fprintf(stderr,
 202                                         " failed to find additional options for target %s\n\n",
 203                                         optarg);
 204                                 return -1;
 205                         }
 206                         ok++;
 207                         break;
 208
 209                 default:
 210 #if XTABLES_VERSION_CODE >= 6
 211                         if (m != NULL && m->x6_parse != NULL) {
 212                                 xtables_option_tpcall(c, argv, 0, m, &fw);
 213 #else
 214                         if (m != NULL && m->parse != NULL) {
 215                                 m->parse(c - m->option_offset, argv, 0,
 216                                          &m->tflags, NULL, &m->t);
 217 #endif
 218                         } else {
 219                                 fprintf(stderr,
 220                                         "failed to find target %s\n\n", optarg);
 221                                 return -1;
 222
 223                         }
 224                         ok++;
 225                         break;
 226                 }
 227         }
 228
 229         if (argc > optind) {
 230                 if (matches(argv[optind], "index") == 0) {
 231                         if (get_u32(&index, argv[optind + 1], 10)) {
 232                                 fprintf(stderr, "Illegal \"index\"\n");
 233                                 xtables_free_opts(1);
 234                                 return -1;
 235                         }
 236                         iok++;
 237
 238                         optind += 2;
 239                 }
 240         }
 241
 242         if (!ok && !iok) {
 243                 fprintf(stderr, " ipt Parser BAD!! (%s)\n", *argv);
 244                 return -1;
 245         }
 246
 247         /* check that we passed the correct parameters to the target */
 248 #if XTABLES_VERSION_CODE >= 6
 249         if (m)
 250                 xtables_option_tfcall(m);
 251 #else
 252         if (m && m->final_check)
 253                 m->final_check(m->tflags);
 254 #endif
 255
 256         {
 257                 struct tcmsg *t = NLMSG_DATA(n);
 258
 259                 if (t->tcm_parent != TC_H_ROOT
 260                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 261                         hook = NF_IP_PRE_ROUTING;
 262                 } else {
 263                         hook = NF_IP_POST_ROUTING;
 264                 }
 265         }
 266
 267         tail = addattr_nest(n, MAX_MSG, tca_id);
 268         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 269         fprintf(stdout, "\ttarget: ");
 270
 271         if (m) {
 272                 if (m->print)
 273                         m->print(NULL, m->t, 0);
 274                 else
 275                         printf("%s ", m->name);
 276         }
 277         fprintf(stdout, " index %d\n", index);
 278
 279         if (strlen(tname) >= 16) {
 280                 size = 15;
 281                 k[15] = 0;
 282         } else {
 283                 size = 1 + strlen(tname);
 284         }
 285         strncpy(k, tname, size);
 286
 287         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 288         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 289         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 290         if (m)
 291                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 292         addattr_nest_end(n, tail);
 293
 294         argv += optind;
 295         *argc_p -= argc;
 296         *argv_p = argv;
 297
 298         optind = 0;
 299         xtables_free_opts(1);
 300
 301         if (m) {
 302                 /* Clear flags if target will be used again */
 303                 m->tflags = 0;
 304                 m->used = 0;
 305                 /* Free allocated memory */
 306                 if (m->t)
 307                         free(m->t);
 308         }
 309
 310         return 0;
 311
 312 }
 313
 314 static int
 315 print_ipt(struct action_util *au, FILE *f, struct rtattr *arg)
 316 {
 317         struct xtables_target *m;
 318         struct rtattr *tb[TCA_IPT_MAX + 1];
 319         struct xt_entry_target *t = NULL;
 320         __u32 hook;
 321
 322         if (arg == NULL)
 323                 return -1;
 324
 325         /* copy tcipt_globals because .opts will be modified by iptables */
 326         struct xtables_globals tmp_tcipt_globals = tcipt_globals;
 327
 328         xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
 329         set_lib_dir();
 330
 331         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 332
 333         if (tb[TCA_IPT_TABLE] == NULL) {
 334                 fprintf(stderr, "Missing ipt table name, assuming mangle\n");
 335         } else {
 336                 fprintf(f, "tablename: %s ",
 337                         rta_getattr_str(tb[TCA_IPT_TABLE]));
 338         }
 339
 340         if (tb[TCA_IPT_HOOK] == NULL) {
 341                 fprintf(stderr, "Missing ipt hook name\n ");
 342                 return -1;
 343         }
 344
 345         if (tb[TCA_IPT_TARG] == NULL) {
 346                 fprintf(stderr, "Missing ipt target parameters\n");
 347                 return -1;
 348         }
 349
 350         hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);
 351         fprintf(f, " hook: %s\n", ipthooks[hook]);
 352
 353         t = RTA_DATA(tb[TCA_IPT_TARG]);
 354         m = xtables_find_target(t->u.user.name, XTF_TRY_LOAD);
 355         if (!m) {
 356                 fprintf(stderr, " failed to find target %s\n\n",
 357                         t->u.user.name);
 358                 return -1;
 359         }
 360         if (build_st(m, t) < 0) {
 361                 fprintf(stderr, " %s error\n", m->name);
 362                 return -1;
 363         }
 364
 365         if (get_xtables_target_opts(&tmp_tcipt_globals, m) < 0) {
 366                 fprintf(stderr,
 367                         " failed to find additional options for target %s\n\n",
 368                         t->u.user.name);
 369                 return -1;
 370         }
 371         fprintf(f, "\ttarget ");
 372         m->print(NULL, m->t, 0);
 373         if (tb[TCA_IPT_INDEX] == NULL) {
 374                 fprintf(f, " [NULL ipt target index ]\n");
 375         } else {
 376                 __u32 index;
 377
 378                 index = rta_getattr_u32(tb[TCA_IPT_INDEX]);
 379                 fprintf(f, "\n\tindex %u", index);
 380         }
 381
 382         if (tb[TCA_IPT_CNT]) {
 383                 struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);
 384
 385                 fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 386         }
 387         if (show_stats) {
 388                 if (tb[TCA_IPT_TM]) {
 389                         struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 390
 391                         print_tm(f, tm);
 392                 }
 393         }
 394         fprintf(f, "\n");
 395
 396         xtables_free_opts(1);
 397
 398         return 0;
 399 }
 400
 401 struct action_util xt_action_util = {
 402         .id = "xt",
 403         .parse_aopt = parse_ipt,
 404         .print_aopt = print_ipt,
 405 };