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