src/libiptc/libip6tc.c

   1 /**
   2  * This file was imported from the iptables sources.
   3  * Copyright (C) 1999-2008 Netfilter Core Team
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; only version 2 of the License is applicable.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  17  */
  18
  19 /* Library which manipulates firewall rules.  Version 0.1. */
  20
  21 /* Architecture of firewall rules is as follows:
  22  *
  23  * Chains go INPUT, FORWARD, OUTPUT then user chains.
  24  * Each user chain starts with an ERROR node.
  25  * Every chain ends with an unconditional jump: a RETURN for user chains,
  26  * and a POLICY for built-ins.
  27  */
  28
  29 /* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See
  30    COPYING for details). */
  31
  32 #include <assert.h>
  33 #include <string.h>
  34 #include <errno.h>
  35 #include <stdlib.h>
  36 #include <stdio.h>
  37 #include <unistd.h>
  38 #include <arpa/inet.h>
  39
  40 #ifdef DEBUG_CONNTRACK
  41 #define inline
  42 #endif
  43
  44 #if !defined(__GLIBC__) || (__GLIBC__ < 2)
  45 typedef unsigned int socklen_t;
  46 #endif
  47
  48 #include "libip6tc.h"
  49
  50 #define HOOK_PRE_ROUTING        NF_IP6_PRE_ROUTING
  51 #define HOOK_LOCAL_IN           NF_IP6_LOCAL_IN
  52 #define HOOK_FORWARD            NF_IP6_FORWARD
  53 #define HOOK_LOCAL_OUT          NF_IP6_LOCAL_OUT
  54 #define HOOK_POST_ROUTING       NF_IP6_POST_ROUTING
  55
  56 #define STRUCT_ENTRY_TARGET     struct ip6t_entry_target
  57 #define STRUCT_ENTRY            struct ip6t_entry
  58 #define STRUCT_ENTRY_MATCH      struct ip6t_entry_match
  59 #define STRUCT_GETINFO          struct ip6t_getinfo
  60 #define STRUCT_GET_ENTRIES      struct ip6t_get_entries
  61 #define STRUCT_COUNTERS         struct ip6t_counters
  62 #define STRUCT_COUNTERS_INFO    struct ip6t_counters_info
  63 #define STRUCT_STANDARD_TARGET  struct ip6t_standard_target
  64 #define STRUCT_REPLACE          struct ip6t_replace
  65
  66 #define STRUCT_TC_HANDLE        struct ip6tc_handle
  67 #define TC_HANDLE_T             ip6tc_handle_t
  68
  69 #define ENTRY_ITERATE           IP6T_ENTRY_ITERATE
  70 #define TABLE_MAXNAMELEN        IP6T_TABLE_MAXNAMELEN
  71 #define FUNCTION_MAXNAMELEN     IP6T_FUNCTION_MAXNAMELEN
  72
  73 #define GET_TARGET              ip6t_get_target
  74
  75 #define ERROR_TARGET            IP6T_ERROR_TARGET
  76 #define NUMHOOKS                NF_IP6_NUMHOOKS
  77
  78 #define IPT_CHAINLABEL          ip6t_chainlabel
  79
  80 #define TC_DUMP_ENTRIES         dump_entries6
  81 #define TC_IS_CHAIN             ip6tc_is_chain
  82 #define TC_FIRST_CHAIN          ip6tc_first_chain
  83 #define TC_NEXT_CHAIN           ip6tc_next_chain
  84 #define TC_FIRST_RULE           ip6tc_first_rule
  85 #define TC_NEXT_RULE            ip6tc_next_rule
  86 #define TC_GET_TARGET           ip6tc_get_target
  87 #define TC_BUILTIN              ip6tc_builtin
  88 #define TC_GET_POLICY           ip6tc_get_policy
  89 #define TC_INSERT_ENTRY         ip6tc_insert_entry
  90 #define TC_REPLACE_ENTRY        ip6tc_replace_entry
  91 #define TC_APPEND_ENTRY         ip6tc_append_entry
  92 #define TC_DELETE_ENTRY         ip6tc_delete_entry
  93 #define TC_DELETE_NUM_ENTRY     ip6tc_delete_num_entry
  94 #define TC_CHECK_PACKET         ip6tc_check_packet
  95 #define TC_FLUSH_ENTRIES        ip6tc_flush_entries
  96 #define TC_ZERO_ENTRIES         ip6tc_zero_entries
  97 #define TC_ZERO_COUNTER         ip6tc_zero_counter
  98 #define TC_READ_COUNTER         ip6tc_read_counter
  99 #define TC_SET_COUNTER          ip6tc_set_counter
 100 #define TC_CREATE_CHAIN         ip6tc_create_chain
 101 #define TC_GET_REFERENCES       ip6tc_get_references
 102 #define TC_DELETE_CHAIN         ip6tc_delete_chain
 103 #define TC_RENAME_CHAIN         ip6tc_rename_chain
 104 #define TC_SET_POLICY           ip6tc_set_policy
 105 #define TC_GET_RAW_SOCKET       ip6tc_get_raw_socket
 106 #define TC_INIT                 ip6tc_init
 107 #define TC_FREE                 ip6tc_free
 108 #define TC_COMMIT               ip6tc_commit
 109 #define TC_STRERROR             ip6tc_strerror
 110 #define TC_NUM_RULES            ip6tc_num_rules
 111 #define TC_GET_RULE             ip6tc_get_rule
 112
 113 #define TC_AF                   AF_INET6
 114 #define TC_IPPROTO              IPPROTO_IPV6
 115
 116 #define SO_SET_REPLACE          IP6T_SO_SET_REPLACE
 117 #define SO_SET_ADD_COUNTERS     IP6T_SO_SET_ADD_COUNTERS
 118 #define SO_GET_INFO             IP6T_SO_GET_INFO
 119 #define SO_GET_ENTRIES          IP6T_SO_GET_ENTRIES
 120 #define SO_GET_VERSION          IP6T_SO_GET_VERSION
 121
 122 #define STANDARD_TARGET         IP6T_STANDARD_TARGET
 123 #define LABEL_RETURN            IP6TC_LABEL_RETURN
 124 #define LABEL_ACCEPT            IP6TC_LABEL_ACCEPT
 125 #define LABEL_DROP              IP6TC_LABEL_DROP
 126 #define LABEL_QUEUE             IP6TC_LABEL_QUEUE
 127
 128 #define ALIGN                   IP6T_ALIGN
 129 #define RETURN                  IP6T_RETURN
 130
 131 #include "libiptc.c"
 132
 133 #define BIT6(a, l) \
 134  ((ntohl(a->s6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1)
 135
 136 int
 137 ipv6_prefix_length(const struct in6_addr *a)
 138 {
 139         int l, i;
 140         for (l = 0; l < 128; l++) {
 141                 if (BIT6(a, l) == 0)
 142                         break;
 143         }
 144         for (i = l + 1; i < 128; i++) {
 145                 if (BIT6(a, i) == 1)
 146                         return -1;
 147         }
 148         return l;
 149 }
 150
 151 static int
 152 dump_entry(struct ip6t_entry *e, const ip6tc_handle_t handle)
 153 {
 154         size_t i;
 155         char buf[40];
 156         int len;
 157         struct ip6t_entry_target *t;
 158
 159         printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
 160                iptcb_entry2offset(handle, e));
 161         puts("SRC IP: ");
 162         inet_ntop(AF_INET6, &e->ipv6.src, buf, sizeof buf);
 163         puts(buf);
 164         putchar('/');
 165         len = ipv6_prefix_length(&e->ipv6.smsk);
 166         if (len != -1)
 167                 printf("%d", len);
 168         else {
 169                 inet_ntop(AF_INET6, &e->ipv6.smsk, buf, sizeof buf);
 170                 puts(buf);
 171         }
 172         putchar('\n');
 173
 174         puts("DST IP: ");
 175         inet_ntop(AF_INET6, &e->ipv6.dst, buf, sizeof buf);
 176         puts(buf);
 177         putchar('/');
 178         len = ipv6_prefix_length(&e->ipv6.dmsk);
 179         if (len != -1)
 180                 printf("%d", len);
 181         else {
 182                 inet_ntop(AF_INET6, &e->ipv6.dmsk, buf, sizeof buf);
 183                 puts(buf);
 184         }
 185         putchar('\n');
 186
 187         printf("Interface: `%s'/", e->ipv6.iniface);
 188         for (i = 0; i < IFNAMSIZ; i++)
 189                 printf("%c", e->ipv6.iniface_mask[i] ? 'X' : '.');
 190         printf("to `%s'/", e->ipv6.outiface);
 191         for (i = 0; i < IFNAMSIZ; i++)
 192                 printf("%c", e->ipv6.outiface_mask[i] ? 'X' : '.');
 193         printf("\nProtocol: %u\n", e->ipv6.proto);
 194         if (e->ipv6.flags & IP6T_F_TOS)
 195                 printf("TOS: %u\n", e->ipv6.tos);
 196         printf("Flags: %02X\n", e->ipv6.flags);
 197         printf("Invflags: %02X\n", e->ipv6.invflags);
 198         printf("Counters: %llu packets, %llu bytes\n",
 199                (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
 200         printf("Cache: %08X\n", e->nfcache);
 201
 202         IP6T_MATCH_ITERATE(e, print_match);
 203
 204         t = ip6t_get_target(e);
 205         printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
 206         if (strcmp(t->u.user.name, IP6T_STANDARD_TARGET) == 0) {
 207                 int pos = *(int *)t->data;
 208                 if (pos < 0)
 209                         printf("verdict=%s\n",
 210                                pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
 211                                : pos == -NF_DROP-1 ? "NF_DROP"
 212                                : pos == IP6T_RETURN ? "RETURN"
 213                                : "UNKNOWN");
 214                 else
 215                         printf("verdict=%u\n", pos);
 216         } else if (strcmp(t->u.user.name, IP6T_ERROR_TARGET) == 0)
 217                 printf("error=`%s'\n", t->data);
 218
 219         printf("\n");
 220         return 0;
 221 }
 222
 223 static unsigned char *
 224 is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b,
 225         unsigned char *matchmask)
 226 {
 227         unsigned int i;
 228         unsigned char *mptr;
 229
 230         /* Always compare head structures: ignore mask here. */
 231         if (memcmp(&a->ipv6.src, &b->ipv6.src, sizeof(struct in6_addr))
 232             || memcmp(&a->ipv6.dst, &b->ipv6.dst, sizeof(struct in6_addr))
 233             || memcmp(&a->ipv6.smsk, &b->ipv6.smsk, sizeof(struct in6_addr))
 234             || memcmp(&a->ipv6.dmsk, &b->ipv6.dmsk, sizeof(struct in6_addr))
 235             || a->ipv6.proto != b->ipv6.proto
 236             || a->ipv6.tos != b->ipv6.tos
 237             || a->ipv6.flags != b->ipv6.flags
 238             || a->ipv6.invflags != b->ipv6.invflags)
 239                 return NULL;
 240
 241         for (i = 0; i < IFNAMSIZ; i++) {
 242                 if (a->ipv6.iniface_mask[i] != b->ipv6.iniface_mask[i])
 243                         return NULL;
 244                 if ((a->ipv6.iniface[i] & a->ipv6.iniface_mask[i])
 245                     != (b->ipv6.iniface[i] & b->ipv6.iniface_mask[i]))
 246                         return NULL;
 247                 if (a->ipv6.outiface_mask[i] != b->ipv6.outiface_mask[i])
 248                         return NULL;
 249                 if ((a->ipv6.outiface[i] & a->ipv6.outiface_mask[i])
 250                     != (b->ipv6.outiface[i] & b->ipv6.outiface_mask[i]))
 251                         return NULL;
 252         }
 253
 254         if (a->target_offset != b->target_offset
 255             || a->next_offset != b->next_offset)
 256                 return NULL;
 257
 258         mptr = matchmask + sizeof(STRUCT_ENTRY);
 259         if (IP6T_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
 260                 return NULL;
 261         mptr += IP6T_ALIGN(sizeof(struct ip6t_entry_target));
 262
 263         return mptr;
 264 }
 265
 266 /* All zeroes == unconditional rule. */
 267 static inline int
 268 unconditional(const struct ip6t_ip6 *ipv6)
 269 {
 270         unsigned int i;
 271
 272         for (i = 0; i < sizeof(*ipv6); i++)
 273                 if (((char *)ipv6)[i])
 274                         break;
 275
 276         return (i == sizeof(*ipv6));
 277 }
 278
 279 #ifdef IPTC_DEBUG
 280 /* Do every conceivable sanity check on the handle */
 281 static void
 282 do_check(TC_HANDLE_T h, unsigned int line)
 283 {
 284         unsigned int i, n;
 285         unsigned int user_offset; /* Offset of first user chain */
 286         int was_return;
 287
 288         assert(h->changed == 0 || h->changed == 1);
 289         if (strcmp(h->info.name, "filter") == 0) {
 290                 assert(h->info.valid_hooks
 291                        == (1 << NF_IP6_LOCAL_IN
 292                            | 1 << NF_IP6_FORWARD
 293                            | 1 << NF_IP6_LOCAL_OUT));
 294
 295                 /* Hooks should be first three */
 296                 assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == 0);
 297
 298                 n = get_chain_end(h, 0);
 299                 n += get_entry(h, n)->next_offset;
 300                 assert(h->info.hook_entry[NF_IP6_FORWARD] == n);
 301
 302                 n = get_chain_end(h, n);
 303                 n += get_entry(h, n)->next_offset;
 304                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 305
 306                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 307         } else if (strcmp(h->info.name, "nat") == 0) {
 308                 assert((h->info.valid_hooks
 309                         == (1 << NF_IP6_PRE_ROUTING
 310                             | 1 << NF_IP6_LOCAL_OUT
 311                             | 1 << NF_IP6_POST_ROUTING)) ||
 312                        (h->info.valid_hooks
 313                         == (1 << NF_IP6_PRE_ROUTING
 314                             | 1 << NF_IP6_LOCAL_IN
 315                             | 1 << NF_IP6_LOCAL_OUT
 316                             | 1 << NF_IP6_POST_ROUTING)));
 317
 318                 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
 319
 320                 n = get_chain_end(h, 0);
 321
 322                 n += get_entry(h, n)->next_offset;
 323                 assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n);
 324                 n = get_chain_end(h, n);
 325
 326                 n += get_entry(h, n)->next_offset;
 327                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 328                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 329
 330                 if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) {
 331                         n = get_chain_end(h, n);
 332                         n += get_entry(h, n)->next_offset;
 333                         assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n);
 334                         user_offset = h->info.hook_entry[NF_IP6_LOCAL_IN];
 335                 }
 336
 337         } else if (strcmp(h->info.name, "mangle") == 0) {
 338                 /* This code is getting ugly because linux < 2.4.18-pre6 had
 339                  * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
 340                  * */
 341                 assert((h->info.valid_hooks
 342                         == (1 << NF_IP6_PRE_ROUTING
 343                             | 1 << NF_IP6_LOCAL_OUT)) ||
 344                        (h->info.valid_hooks
 345                         == (1 << NF_IP6_PRE_ROUTING
 346                             | 1 << NF_IP6_LOCAL_IN
 347                             | 1 << NF_IP6_FORWARD
 348                             | 1 << NF_IP6_LOCAL_OUT
 349                             | 1 << NF_IP6_POST_ROUTING)));
 350
 351                 /* Hooks should be first five */
 352                 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
 353
 354                 n = get_chain_end(h, 0);
 355
 356                 if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) {
 357                         n += get_entry(h, n)->next_offset;
 358                         assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n);
 359                         n = get_chain_end(h, n);
 360                 }
 361
 362                 if (h->info.valid_hooks & (1 << NF_IP6_FORWARD)) {
 363                         n += get_entry(h, n)->next_offset;
 364                         assert(h->info.hook_entry[NF_IP6_FORWARD] == n);
 365                         n = get_chain_end(h, n);
 366                 }
 367
 368                 n += get_entry(h, n)->next_offset;
 369                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 370                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 371
 372                 if (h->info.valid_hooks & (1 << NF_IP6_POST_ROUTING)) {
 373                         n = get_chain_end(h, n);
 374                         n += get_entry(h, n)->next_offset;
 375                         assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n);
 376                         user_offset = h->info.hook_entry[NF_IP6_POST_ROUTING];
 377                 }
 378         } else if (strcmp(h->info.name, "raw") == 0) {
 379                 assert(h->info.valid_hooks
 380                        == (1 << NF_IP6_PRE_ROUTING
 381                            | 1 << NF_IP6_LOCAL_OUT));
 382
 383                 /* Hooks should be first three */
 384                 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
 385
 386                 n = get_chain_end(h, n);
 387                 n += get_entry(h, n)->next_offset;
 388                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 389
 390                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 391         } else {
 392                 fprintf(stderr, "Unknown table `%s'\n", h->info.name);
 393                 abort();
 394         }
 395
 396         /* User chain == end of last builtin + policy entry */
 397         user_offset = get_chain_end(h, user_offset);
 398         user_offset += get_entry(h, user_offset)->next_offset;
 399
 400         /* Overflows should be end of entry chains, and unconditional
 401            policy nodes. */
 402         for (i = 0; i < NUMHOOKS; i++) {
 403                 STRUCT_ENTRY *e;
 404                 STRUCT_STANDARD_TARGET *t;
 405
 406                 if (!(h->info.valid_hooks & (1 << i)))
 407                         continue;
 408                 assert(h->info.underflow[i]
 409                        == get_chain_end(h, h->info.hook_entry[i]));
 410
 411                 e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
 412                 assert(unconditional(&e->ipv6));
 413                 assert(e->target_offset == sizeof(*e));
 414                 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
 415                 printf("target_size=%u, align=%u\n",
 416                         t->target.u.target_size, ALIGN(sizeof(*t)));
 417                 assert(t->target.u.target_size == ALIGN(sizeof(*t)));
 418                 assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
 419
 420                 assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
 421                 assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
 422
 423                 /* Hooks and underflows must be valid entries */
 424                 iptcb_entry2index(h, get_entry(h, h->info.hook_entry[i]));
 425                 iptcb_entry2index(h, get_entry(h, h->info.underflow[i]));
 426         }
 427
 428         assert(h->info.size
 429                >= h->info.num_entries * (sizeof(STRUCT_ENTRY)
 430                                          +sizeof(STRUCT_STANDARD_TARGET)));
 431
 432         assert(h->entries.size
 433                >= (h->new_number
 434                    * (sizeof(STRUCT_ENTRY)
 435                       + sizeof(STRUCT_STANDARD_TARGET))));
 436         assert(strcmp(h->info.name, h->entries.name) == 0);
 437
 438         i = 0; n = 0;
 439         was_return = 0;
 440
 441 #if 0
 442         /* Check all the entries. */
 443         ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
 444                       check_entry, &i, &n, user_offset, &was_return, h);
 445
 446         assert(i == h->new_number);
 447         assert(n == h->entries.size);
 448
 449         /* Final entry must be error node */
 450         assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
 451                       ->u.user.name,
 452                       ERROR_TARGET) == 0);
 453 #endif
 454 }
 455 #endif /*IPTC_DEBUG*/