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 ipt_entry fw;
 124         struct rtattr *tail;
 125
 126         int c;
 127         int rargc = *argc_p;
 128         char **argv = *argv_p;
 129         int argc = 0, iargc = 0;
 130         char k[16];
 131         int size = 0;
 132         int iok = 0, ok = 0;
 133         __u32 hook = 0, index = 0;
 134         struct option *opts = NULL;
 135
 136         /* copy tcipt_globals because .opts will be modified by iptables */
 137         struct xtables_globals tmp_tcipt_globals = tcipt_globals;
 138         xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
 139         set_lib_dir();
 140
 141         {
 142                 int i;
 143
 144                 for (i = 0; i < rargc; i++) {
 145                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 146                                 break;
 147                         }
 148                 }
 149                 iargc = argc = i;
 150         }
 151
 152         if (argc <= 2) {
 153                 fprintf(stderr, "bad arguments to ipt %d vs %d\n", argc, rargc);
 154                 return -1;
 155         }
 156
 157         while (1) {
 158                 c = getopt_long(argc, argv, "j:", tmp_tcipt_globals.opts, NULL);
 159                 if (c == -1)
 160                         break;
 161                 switch (c) {
 162                 case 'j':
 163                         m = xtables_find_target(optarg, XTF_TRY_LOAD);
 164                         if (m != NULL) {
 165
 166                                 if (build_st(m, NULL) < 0) {
 167                                         printf(" %s error\n", m->name);
 168                                         return -1;
 169                                 }
 170 #if (XTABLES_VERSION_CODE >= 6)
 171                         opts = xtables_options_xfrm(tmp_tcipt_globals.orig_opts,
 172                                                     tmp_tcipt_globals.opts,
 173                                                     m->x6_options,
 174                                                     &m->option_offset);
 175 #else
 176                         opts = xtables_merge_options(tmp_tcipt_globals.opts,
 177                                                      m->extra_opts,
 178                                                      &m->option_offset);
 179 #endif
 180                         if (opts == NULL) {
 181                                 fprintf(stderr, " failed to find additional options for target %s\n\n", optarg);
 182                                 return -1;
 183                         } else
 184                                 tmp_tcipt_globals.opts = opts;
 185                         } else {
 186                                 fprintf(stderr, " failed to find target %s\n\n", optarg);
 187                                 return -1;
 188                         }
 189                         ok++;
 190                         break;
 191
 192                 default:
 193                         memset(&fw, 0, sizeof(fw));
 194 #if (XTABLES_VERSION_CODE >= 6)
 195                 if (m != NULL && m->x6_parse != NULL) {
 196                         xtables_option_tpcall(c, argv, 0, m, NULL);
 197 #else
 198                 if (m != NULL && m->parse != NULL) {
 199                         m->parse(c - m->option_offset, argv, 0, &m->tflags,
 200                                  NULL, &m->t);
 201 #endif
 202                         } else {
 203                                 fprintf(stderr, "failed to find target %s\n\n", optarg);
 204                                 return -1;
 205
 206                         }
 207                         ok++;
 208                         break;
 209                 }
 210         }
 211
 212         if (iargc > optind) {
 213                 if (matches(argv[optind], "index") == 0) {
 214                         if (get_u32(&index, argv[optind + 1], 10)) {
 215                                 fprintf(stderr, "Illegal \"index\"\n");
 216                                 xtables_free_opts(1);
 217                                 return -1;
 218                         }
 219                         iok++;
 220
 221                         optind += 2;
 222                 }
 223         }
 224
 225         if (!ok && !iok) {
 226                 fprintf(stderr, " ipt Parser BAD!! (%s)\n", *argv);
 227                 return -1;
 228         }
 229
 230         /* check that we passed the correct parameters to the target */
 231 #if (XTABLES_VERSION_CODE >= 6)
 232         if (m)
 233                 xtables_option_tfcall(m);
 234 #else
 235         if (m && m->final_check)
 236                 m->final_check(m->tflags);
 237 #endif
 238
 239         {
 240                 struct tcmsg *t = NLMSG_DATA(n);
 241
 242                 if (t->tcm_parent != TC_H_ROOT
 243                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 244                         hook = NF_IP_PRE_ROUTING;
 245                 } else {
 246                         hook = NF_IP_POST_ROUTING;
 247                 }
 248         }
 249
 250         tail = NLMSG_TAIL(n);
 251         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 252         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 253         fprintf(stdout, "\ttarget: ");
 254
 255         if (m) {
 256                 if (m->print)
 257                         m->print(NULL, m->t, 0);
 258                 else
 259                         printf("%s ", m->name);
 260         }
 261         fprintf(stdout, " index %d\n", index);
 262
 263         if (strlen(tname) > 16) {
 264                 size = 16;
 265                 k[15] = 0;
 266         } else {
 267                 size = 1 + strlen(tname);
 268         }
 269         strncpy(k, tname, size);
 270
 271         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 272         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 273         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 274         if (m)
 275                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 276         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 277
 278         argc -= optind;
 279         argv += optind;
 280         *argc_p = rargc - iargc;
 281         *argv_p = argv;
 282
 283         optind = 0;
 284         xtables_free_opts(1);
 285
 286         if (m) {
 287                 /* Clear flags if target will be used again */
 288                 m->tflags = 0;
 289                 m->used = 0;
 290                 /* Free allocated memory */
 291                 if (m->t)
 292                         free(m->t);
 293         }
 294
 295         return 0;
 296
 297 }
 298
 299 static int
 300 print_ipt(struct action_util *au, FILE * f, struct rtattr *arg)
 301 {
 302         struct rtattr *tb[TCA_IPT_MAX + 1];
 303         struct xt_entry_target *t = NULL;
 304         struct option *opts = NULL;
 305
 306         if (arg == NULL)
 307                 return -1;
 308
 309         /* copy tcipt_globals because .opts will be modified by iptables */
 310         struct xtables_globals tmp_tcipt_globals = tcipt_globals;
 311
 312         xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
 313         set_lib_dir();
 314
 315         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 316
 317         if (tb[TCA_IPT_TABLE] == NULL) {
 318                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 319         } else {
 320                 fprintf(f, "tablename: %s ",
 321                         rta_getattr_str(tb[TCA_IPT_TABLE]));
 322         }
 323
 324         if (tb[TCA_IPT_HOOK] == NULL) {
 325                 fprintf(f, "[NULL ipt hook name ]\n ");
 326                 return -1;
 327         } else {
 328                 __u32 hook;
 329
 330                 hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);
 331                 fprintf(f, " hook: %s\n", ipthooks[hook]);
 332         }
 333
 334         if (tb[TCA_IPT_TARG] == NULL) {
 335                 fprintf(f, "\t[NULL ipt target parameters ]\n");
 336                 return -1;
 337         } else {
 338                 struct xtables_target *m = NULL;
 339
 340                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 341                 m = xtables_find_target(t->u.user.name, XTF_TRY_LOAD);
 342                 if (m != NULL) {
 343                         if (build_st(m, t) < 0) {
 344                                 fprintf(stderr, " %s error\n", m->name);
 345                                 return -1;
 346                         }
 347
 348 #if (XTABLES_VERSION_CODE >= 6)
 349                 opts = xtables_options_xfrm(tmp_tcipt_globals.orig_opts,
 350                                             tmp_tcipt_globals.opts,
 351                                             m->x6_options,
 352                                             &m->option_offset);
 353 #else
 354                 opts = xtables_merge_options(tmp_tcipt_globals.opts,
 355                                              m->extra_opts,
 356                                              &m->option_offset);
 357 #endif
 358         if (opts == NULL) {
 359                 fprintf(stderr, " failed to find additional options for target %s\n\n", optarg);
 360                 return -1;
 361         } else
 362                 tmp_tcipt_globals.opts = opts;
 363                 } else {
 364                         fprintf(stderr, " failed to find target %s\n\n",
 365                                 t->u.user.name);
 366                         return -1;
 367                 }
 368                 fprintf(f, "\ttarget ");
 369                 m->print(NULL, m->t, 0);
 370                 if (tb[TCA_IPT_INDEX] == NULL) {
 371                         fprintf(f, " [NULL ipt target index ]\n");
 372                 } else {
 373                         __u32 index;
 374
 375                         index = rta_getattr_u32(tb[TCA_IPT_INDEX]);
 376                         fprintf(f, "\n\tindex %d", index);
 377                 }
 378
 379                 if (tb[TCA_IPT_CNT]) {
 380                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);
 381
 382                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 383                 }
 384                 if (show_stats) {
 385                         if (tb[TCA_IPT_TM]) {
 386                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 387
 388                                 print_tm(f, tm);
 389                         }
 390                 }
 391                 fprintf(f, "\n");
 392
 393         }
 394         xtables_free_opts(1);
 395
 396         return 0;
 397 }
 398
 399 struct action_util xt_action_util = {
 400         .id = "xt",
 401         .parse_aopt = parse_ipt,
 402         .print_aopt = print_ipt,
 403 };