release/src/router/iptables/libiptc/libip6tc.c

   1 /* Library which manipulates firewall rules.  Version 0.1. */
   2
   3 /* Architecture of firewall rules is as follows:
   4  *
   5  * Chains go INPUT, FORWARD, OUTPUT then user chains.
   6  * Each user chain starts with an ERROR node.
   7  * Every chain ends with an unconditional jump: a RETURN for user chains,
   8  * and a POLICY for built-ins.
   9  */
  10
  11 /* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See
  12    COPYING for details). */
  13
  14 #include <assert.h>
  15 #include <string.h>
  16 #include <errno.h>
  17 #include <stdlib.h>
  18 #include <stdio.h>
  19 #include <unistd.h>
  20 #include <arpa/inet.h>
  21
  22 #ifdef DEBUG_CONNTRACK
  23 #define inline
  24 #endif
  25
  26 #if !defined(__GLIBC__) || (__GLIBC__ < 2)
  27 typedef unsigned int socklen_t;
  28 #endif
  29
  30 #include "libiptc/libip6tc.h"
  31
  32 #define HOOK_PRE_ROUTING        NF_IP6_PRE_ROUTING
  33 #define HOOK_LOCAL_IN           NF_IP6_LOCAL_IN
  34 #define HOOK_FORWARD            NF_IP6_FORWARD
  35 #define HOOK_LOCAL_OUT          NF_IP6_LOCAL_OUT
  36 #define HOOK_POST_ROUTING       NF_IP6_POST_ROUTING
  37
  38 #define STRUCT_ENTRY_TARGET     struct ip6t_entry_target
  39 #define STRUCT_ENTRY            struct ip6t_entry
  40 #define STRUCT_ENTRY_MATCH      struct ip6t_entry_match
  41 #define STRUCT_GETINFO          struct ip6t_getinfo
  42 #define STRUCT_GET_ENTRIES      struct ip6t_get_entries
  43 #define STRUCT_COUNTERS         struct ip6t_counters
  44 #define STRUCT_COUNTERS_INFO    struct ip6t_counters_info
  45 #define STRUCT_STANDARD_TARGET  struct ip6t_standard_target
  46 #define STRUCT_REPLACE          struct ip6t_replace
  47
  48 #define STRUCT_TC_HANDLE        struct ip6tc_handle
  49 #define TC_HANDLE_T             ip6tc_handle_t
  50
  51 #define ENTRY_ITERATE           IP6T_ENTRY_ITERATE
  52 #define TABLE_MAXNAMELEN        IP6T_TABLE_MAXNAMELEN
  53 #define FUNCTION_MAXNAMELEN     IP6T_FUNCTION_MAXNAMELEN
  54
  55 #define GET_TARGET              ip6t_get_target
  56
  57 #define ERROR_TARGET            IP6T_ERROR_TARGET
  58 #define NUMHOOKS                NF_IP6_NUMHOOKS
  59
  60 #define IPT_CHAINLABEL          ip6t_chainlabel
  61
  62 #define TC_DUMP_ENTRIES         dump_entries6
  63 #define TC_IS_CHAIN             ip6tc_is_chain
  64 #define TC_FIRST_CHAIN          ip6tc_first_chain
  65 #define TC_NEXT_CHAIN           ip6tc_next_chain
  66 #define TC_FIRST_RULE           ip6tc_first_rule
  67 #define TC_NEXT_RULE            ip6tc_next_rule
  68 #define TC_GET_TARGET           ip6tc_get_target
  69 #define TC_BUILTIN              ip6tc_builtin
  70 #define TC_GET_POLICY           ip6tc_get_policy
  71 #define TC_INSERT_ENTRY         ip6tc_insert_entry
  72 #define TC_REPLACE_ENTRY        ip6tc_replace_entry
  73 #define TC_APPEND_ENTRY         ip6tc_append_entry
  74 #define TC_DELETE_ENTRY         ip6tc_delete_entry
  75 #define TC_DELETE_NUM_ENTRY     ip6tc_delete_num_entry
  76 #define TC_CHECK_PACKET         ip6tc_check_packet
  77 #define TC_FLUSH_ENTRIES        ip6tc_flush_entries
  78 #define TC_ZERO_ENTRIES         ip6tc_zero_entries
  79 #define TC_ZERO_COUNTER         ip6tc_zero_counter
  80 #define TC_READ_COUNTER         ip6tc_read_counter
  81 #define TC_SET_COUNTER          ip6tc_set_counter
  82 #define TC_CREATE_CHAIN         ip6tc_create_chain
  83 #define TC_GET_REFERENCES       ip6tc_get_references
  84 #define TC_DELETE_CHAIN         ip6tc_delete_chain
  85 #define TC_RENAME_CHAIN         ip6tc_rename_chain
  86 #define TC_SET_POLICY           ip6tc_set_policy
  87 #define TC_GET_RAW_SOCKET       ip6tc_get_raw_socket
  88 #define TC_INIT                 ip6tc_init
  89 #define TC_FREE                 ip6tc_free
  90 #define TC_COMMIT               ip6tc_commit
  91 #define TC_STRERROR             ip6tc_strerror
  92 #define TC_NUM_RULES            ip6tc_num_rules
  93 #define TC_GET_RULE             ip6tc_get_rule
  94
  95 #define TC_AF                   AF_INET6
  96 #define TC_IPPROTO              IPPROTO_IPV6
  97
  98 #define SO_SET_REPLACE          IP6T_SO_SET_REPLACE
  99 #define SO_SET_ADD_COUNTERS     IP6T_SO_SET_ADD_COUNTERS
 100 #define SO_GET_INFO             IP6T_SO_GET_INFO
 101 #define SO_GET_ENTRIES          IP6T_SO_GET_ENTRIES
 102 #define SO_GET_VERSION          IP6T_SO_GET_VERSION
 103
 104 #define STANDARD_TARGET         IP6T_STANDARD_TARGET
 105 #define LABEL_RETURN            IP6TC_LABEL_RETURN
 106 #define LABEL_ACCEPT            IP6TC_LABEL_ACCEPT
 107 #define LABEL_DROP              IP6TC_LABEL_DROP
 108 #define LABEL_QUEUE             IP6TC_LABEL_QUEUE
 109
 110 #define ALIGN                   IP6T_ALIGN
 111 #define RETURN                  IP6T_RETURN
 112
 113 #include "libiptc.c"
 114
 115 #define BIT6(a, l) \
 116  ((ntohl(a->in6_u.u6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1)
 117
 118 int
 119 ipv6_prefix_length(const struct in6_addr *a)
 120 {
 121         int l, i;
 122         for (l = 0; l < 128; l++) {
 123                 if (BIT6(a, l) == 0)
 124                         break;
 125         }
 126         for (i = l + 1; i < 128; i++) {
 127                 if (BIT6(a, i) == 1)
 128                         return -1;
 129         }
 130         return l;
 131 }
 132
 133 #if 0
 134 static int
 135 dump_entry(struct ip6t_entry *e, const ip6tc_handle_t handle)
 136 {
 137         size_t i;
 138         char buf[40];
 139         int len;
 140         struct ip6t_entry_target *t;
 141
 142         printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
 143                iptcb_entry2offset(handle, e));
 144         puts("SRC IP: ");
 145         inet_ntop(AF_INET6, &e->ipv6.src, buf, sizeof buf);
 146         puts(buf);
 147         putchar('/');
 148         len = ipv6_prefix_length(&e->ipv6.smsk);
 149         if (len != -1)
 150                 printf("%d", len);
 151         else {
 152                 inet_ntop(AF_INET6, &e->ipv6.smsk, buf, sizeof buf);
 153                 puts(buf);
 154         }
 155         putchar('\n');
 156
 157         puts("DST IP: ");
 158         inet_ntop(AF_INET6, &e->ipv6.dst, buf, sizeof buf);
 159         puts(buf);
 160         putchar('/');
 161         len = ipv6_prefix_length(&e->ipv6.dmsk);
 162         if (len != -1)
 163                 printf("%d", len);
 164         else {
 165                 inet_ntop(AF_INET6, &e->ipv6.dmsk, buf, sizeof buf);
 166                 puts(buf);
 167         }
 168         putchar('\n');
 169
 170         printf("Interface: `%s'/", e->ipv6.iniface);
 171         for (i = 0; i < IFNAMSIZ; i++)
 172                 printf("%c", e->ipv6.iniface_mask[i] ? 'X' : '.');
 173         printf("to `%s'/", e->ipv6.outiface);
 174         for (i = 0; i < IFNAMSIZ; i++)
 175                 printf("%c", e->ipv6.outiface_mask[i] ? 'X' : '.');
 176         printf("\nProtocol: %u\n", e->ipv6.proto);
 177         if (e->ipv6.flags & IP6T_F_TOS)
 178                 printf("TOS: %u\n", e->ipv6.tos);
 179         printf("Flags: %02X\n", e->ipv6.flags);
 180         printf("Invflags: %02X\n", e->ipv6.invflags);
 181         printf("Counters: %llu packets, %llu bytes\n",
 182                (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
 183         printf("Cache: %08X ", e->nfcache);
 184         if (e->nfcache & NFC_ALTERED) printf("ALTERED ");
 185         if (e->nfcache & NFC_UNKNOWN) printf("UNKNOWN ");
 186         printf("\n");
 187
 188         IP6T_MATCH_ITERATE(e, print_match);
 189
 190         t = ip6t_get_target(e);
 191         printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
 192         if (strcmp(t->u.user.name, IP6T_STANDARD_TARGET) == 0) {
 193                 int pos = *(int *)t->data;
 194                 if (pos < 0)
 195                         printf("verdict=%s\n",
 196                                pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
 197                                : pos == -NF_DROP-1 ? "NF_DROP"
 198                                : pos == IP6T_RETURN ? "RETURN"
 199                                : "UNKNOWN");
 200                 else
 201                         printf("verdict=%u\n", pos);
 202         } else if (strcmp(t->u.user.name, IP6T_ERROR_TARGET) == 0)
 203                 printf("error=`%s'\n", t->data);
 204
 205         printf("\n");
 206         return 0;
 207 }
 208 #endif
 209
 210 static unsigned char *
 211 is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b,
 212         unsigned char *matchmask)
 213 {
 214         unsigned int i;
 215         unsigned char *mptr;
 216
 217         /* Always compare head structures: ignore mask here. */
 218         if (memcmp(&a->ipv6.src, &b->ipv6.src, sizeof(struct in6_addr))
 219             || memcmp(&a->ipv6.dst, &b->ipv6.dst, sizeof(struct in6_addr))
 220             || memcmp(&a->ipv6.smsk, &b->ipv6.smsk, sizeof(struct in6_addr))
 221             || memcmp(&a->ipv6.dmsk, &b->ipv6.dmsk, sizeof(struct in6_addr))
 222             || a->ipv6.proto != b->ipv6.proto
 223             || a->ipv6.tos != b->ipv6.tos
 224             || a->ipv6.flags != b->ipv6.flags
 225             || a->ipv6.invflags != b->ipv6.invflags)
 226                 return NULL;
 227
 228         for (i = 0; i < IFNAMSIZ; i++) {
 229                 if (a->ipv6.iniface_mask[i] != b->ipv6.iniface_mask[i])
 230                         return NULL;
 231                 if ((a->ipv6.iniface[i] & a->ipv6.iniface_mask[i])
 232                     != (b->ipv6.iniface[i] & b->ipv6.iniface_mask[i]))
 233                         return NULL;
 234                 if (a->ipv6.outiface_mask[i] != b->ipv6.outiface_mask[i])
 235                         return NULL;
 236                 if ((a->ipv6.outiface[i] & a->ipv6.outiface_mask[i])
 237                     != (b->ipv6.outiface[i] & b->ipv6.outiface_mask[i]))
 238                         return NULL;
 239         }
 240
 241         if (a->nfcache != b->nfcache
 242             || a->target_offset != b->target_offset
 243             || a->next_offset != b->next_offset)
 244                 return NULL;
 245
 246         mptr = matchmask + sizeof(STRUCT_ENTRY);
 247         if (IP6T_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
 248                 return NULL;
 249         mptr += IP6T_ALIGN(sizeof(struct ip6t_entry_target));
 250
 251         return mptr;
 252 }
 253
 254 /* All zeroes == unconditional rule. */
 255 static inline int
 256 unconditional(const struct ip6t_ip6 *ipv6)
 257 {
 258         unsigned int i;
 259
 260         for (i = 0; i < sizeof(*ipv6); i++)
 261                 if (((char *)ipv6)[i])
 262                         break;
 263
 264         return (i == sizeof(*ipv6));
 265 }
 266
 267 #ifdef IPTC_DEBUG
 268 /* Do every conceivable sanity check on the handle */
 269 static void
 270 do_check(TC_HANDLE_T h, unsigned int line)
 271 {
 272         unsigned int i, n;
 273         unsigned int user_offset; /* Offset of first user chain */
 274         int was_return;
 275
 276         assert(h->changed == 0 || h->changed == 1);
 277         if (strcmp(h->info.name, "filter") == 0) {
 278                 assert(h->info.valid_hooks
 279                        == (1 << NF_IP6_LOCAL_IN
 280                            | 1 << NF_IP6_FORWARD
 281                            | 1 << NF_IP6_LOCAL_OUT));
 282
 283                 /* Hooks should be first three */
 284                 assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == 0);
 285
 286                 n = get_chain_end(h, 0);
 287                 n += get_entry(h, n)->next_offset;
 288                 assert(h->info.hook_entry[NF_IP6_FORWARD] == n);
 289
 290                 n = get_chain_end(h, n);
 291                 n += get_entry(h, n)->next_offset;
 292                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 293
 294                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 295         } else if (strcmp(h->info.name, "nat") == 0) {
 296                 assert((h->info.valid_hooks
 297                         == (1 << NF_IP6_PRE_ROUTING
 298                             | 1 << NF_IP6_LOCAL_OUT
 299                             | 1 << NF_IP6_POST_ROUTING)) ||
 300                        (h->info.valid_hooks
 301                         == (1 << NF_IP6_PRE_ROUTING
 302                             | 1 << NF_IP6_LOCAL_IN
 303                             | 1 << NF_IP6_LOCAL_OUT
 304                             | 1 << NF_IP6_POST_ROUTING)));
 305
 306                 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
 307
 308                 n = get_chain_end(h, 0);
 309
 310                 n += get_entry(h, n)->next_offset;
 311                 assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n);
 312                 n = get_chain_end(h, n);
 313
 314                 n += get_entry(h, n)->next_offset;
 315                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 316                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 317
 318                 if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) {
 319                         n = get_chain_end(h, n);
 320                         n += get_entry(h, n)->next_offset;
 321                         assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n);
 322                         user_offset = h->info.hook_entry[NF_IP6_LOCAL_IN];
 323                 }
 324
 325         } else if (strcmp(h->info.name, "mangle") == 0) {
 326                 /* This code is getting ugly because linux < 2.4.18-pre6 had
 327                  * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
 328                  * */
 329                 assert((h->info.valid_hooks
 330                         == (1 << NF_IP6_PRE_ROUTING
 331                             | 1 << NF_IP6_LOCAL_OUT)) ||
 332                        (h->info.valid_hooks
 333                         == (1 << NF_IP6_PRE_ROUTING
 334                             | 1 << NF_IP6_LOCAL_IN
 335                             | 1 << NF_IP6_FORWARD
 336                             | 1 << NF_IP6_LOCAL_OUT
 337                             | 1 << NF_IP6_POST_ROUTING)));
 338
 339                 /* Hooks should be first five */
 340                 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
 341
 342                 n = get_chain_end(h, 0);
 343
 344                 if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) {
 345                         n += get_entry(h, n)->next_offset;
 346                         assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n);
 347                         n = get_chain_end(h, n);
 348                 }
 349
 350                 if (h->info.valid_hooks & (1 << NF_IP6_FORWARD)) {
 351                         n += get_entry(h, n)->next_offset;
 352                         assert(h->info.hook_entry[NF_IP6_FORWARD] == n);
 353                         n = get_chain_end(h, n);
 354                 }
 355
 356                 n += get_entry(h, n)->next_offset;
 357                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 358                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 359
 360                 if (h->info.valid_hooks & (1 << NF_IP6_POST_ROUTING)) {
 361                         n = get_chain_end(h, n);
 362                         n += get_entry(h, n)->next_offset;
 363                         assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n);
 364                         user_offset = h->info.hook_entry[NF_IP6_POST_ROUTING];
 365                 }
 366         } else if (strcmp(h->info.name, "raw") == 0) {
 367                 assert(h->info.valid_hooks
 368                        == (1 << NF_IP6_PRE_ROUTING
 369                            | 1 << NF_IP6_LOCAL_OUT));
 370
 371                 /* Hooks should be first three */
 372                 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
 373
 374                 n = get_chain_end(h, n);
 375                 n += get_entry(h, n)->next_offset;
 376                 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
 377
 378                 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
 379         } else {
 380                 fprintf(stderr, "Unknown table `%s'\n", h->info.name);
 381                 abort();
 382         }
 383
 384         /* User chain == end of last builtin + policy entry */
 385         user_offset = get_chain_end(h, user_offset);
 386         user_offset += get_entry(h, user_offset)->next_offset;
 387
 388         /* Overflows should be end of entry chains, and unconditional
 389            policy nodes. */
 390         for (i = 0; i < NUMHOOKS; i++) {
 391                 STRUCT_ENTRY *e;
 392                 STRUCT_STANDARD_TARGET *t;
 393
 394                 if (!(h->info.valid_hooks & (1 << i)))
 395                         continue;
 396                 assert(h->info.underflow[i]
 397                        == get_chain_end(h, h->info.hook_entry[i]));
 398
 399                 e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
 400                 assert(unconditional(&e->ipv6));
 401                 assert(e->target_offset == sizeof(*e));
 402                 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
 403                 printf("target_size=%u, align=%u\n",
 404                         t->target.u.target_size, ALIGN(sizeof(*t)));
 405                 assert(t->target.u.target_size == ALIGN(sizeof(*t)));
 406                 assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
 407
 408                 assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
 409                 assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
 410
 411                 /* Hooks and underflows must be valid entries */
 412                 iptcb_entry2index(h, get_entry(h, h->info.hook_entry[i]));
 413                 iptcb_entry2index(h, get_entry(h, h->info.underflow[i]));
 414         }
 415
 416         assert(h->info.size
 417                >= h->info.num_entries * (sizeof(STRUCT_ENTRY)
 418                                          +sizeof(STRUCT_STANDARD_TARGET)));
 419
 420         assert(h->entries.size
 421                >= (h->new_number
 422                    * (sizeof(STRUCT_ENTRY)
 423                       + sizeof(STRUCT_STANDARD_TARGET))));
 424         assert(strcmp(h->info.name, h->entries.name) == 0);
 425
 426         i = 0; n = 0;
 427         was_return = 0;
 428
 429 #if 0
 430         /* Check all the entries. */
 431         ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
 432                       check_entry, &i, &n, user_offset, &was_return, h);
 433
 434         assert(i == h->new_number);
 435         assert(n == h->entries.size);
 436
 437         /* Final entry must be error node */
 438         assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
 439                       ->u.user.name,
 440                       ERROR_TARGET) == 0);
 441 #endif
 442 }
 443 #endif /*IPTC_DEBUG*/