libip6tc.c revision 51651b64fffc58d4f58d005fa7dc0d9669147c57
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) 27typedef 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 xtc_handle ip6tc_handle 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_FLUSH_ENTRIES ip6tc_flush_entries 77#define TC_ZERO_ENTRIES ip6tc_zero_entries 78#define TC_ZERO_COUNTER ip6tc_zero_counter 79#define TC_READ_COUNTER ip6tc_read_counter 80#define TC_SET_COUNTER ip6tc_set_counter 81#define TC_CREATE_CHAIN ip6tc_create_chain 82#define TC_GET_REFERENCES ip6tc_get_references 83#define TC_DELETE_CHAIN ip6tc_delete_chain 84#define TC_RENAME_CHAIN ip6tc_rename_chain 85#define TC_SET_POLICY ip6tc_set_policy 86#define TC_GET_RAW_SOCKET ip6tc_get_raw_socket 87#define TC_INIT ip6tc_init 88#define TC_FREE ip6tc_free 89#define TC_COMMIT ip6tc_commit 90#define TC_STRERROR ip6tc_strerror 91#define TC_NUM_RULES ip6tc_num_rules 92#define TC_GET_RULE ip6tc_get_rule 93 94#define TC_AF AF_INET6 95#define TC_IPPROTO IPPROTO_IPV6 96 97#define SO_SET_REPLACE IP6T_SO_SET_REPLACE 98#define SO_SET_ADD_COUNTERS IP6T_SO_SET_ADD_COUNTERS 99#define SO_GET_INFO IP6T_SO_GET_INFO 100#define SO_GET_ENTRIES IP6T_SO_GET_ENTRIES 101#define SO_GET_VERSION IP6T_SO_GET_VERSION 102 103#define STANDARD_TARGET IP6T_STANDARD_TARGET 104#define LABEL_RETURN IP6TC_LABEL_RETURN 105#define LABEL_ACCEPT IP6TC_LABEL_ACCEPT 106#define LABEL_DROP IP6TC_LABEL_DROP 107#define LABEL_QUEUE IP6TC_LABEL_QUEUE 108 109#define ALIGN IP6T_ALIGN 110#define RETURN IP6T_RETURN 111 112#include "libiptc.c" 113 114#define BIT6(a, l) \ 115 ((ntohl(a->s6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1) 116 117int 118ipv6_prefix_length(const struct in6_addr *a) 119{ 120 int l, i; 121 for (l = 0; l < 128; l++) { 122 if (BIT6(a, l) == 0) 123 break; 124 } 125 for (i = l + 1; i < 128; i++) { 126 if (BIT6(a, i) == 1) 127 return -1; 128 } 129 return l; 130} 131 132static int 133dump_entry(struct ip6t_entry *e, struct ip6tc_handle *const handle) 134{ 135 size_t i; 136 char buf[40]; 137 int len; 138 struct ip6t_entry_target *t; 139 140 printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e), 141 iptcb_entry2offset(handle, e)); 142 puts("SRC IP: "); 143 inet_ntop(AF_INET6, &e->ipv6.src, buf, sizeof buf); 144 puts(buf); 145 putchar('/'); 146 len = ipv6_prefix_length(&e->ipv6.smsk); 147 if (len != -1) 148 printf("%d", len); 149 else { 150 inet_ntop(AF_INET6, &e->ipv6.smsk, buf, sizeof buf); 151 puts(buf); 152 } 153 putchar('\n'); 154 155 puts("DST IP: "); 156 inet_ntop(AF_INET6, &e->ipv6.dst, buf, sizeof buf); 157 puts(buf); 158 putchar('/'); 159 len = ipv6_prefix_length(&e->ipv6.dmsk); 160 if (len != -1) 161 printf("%d", len); 162 else { 163 inet_ntop(AF_INET6, &e->ipv6.dmsk, buf, sizeof buf); 164 puts(buf); 165 } 166 putchar('\n'); 167 168 printf("Interface: `%s'/", e->ipv6.iniface); 169 for (i = 0; i < IFNAMSIZ; i++) 170 printf("%c", e->ipv6.iniface_mask[i] ? 'X' : '.'); 171 printf("to `%s'/", e->ipv6.outiface); 172 for (i = 0; i < IFNAMSIZ; i++) 173 printf("%c", e->ipv6.outiface_mask[i] ? 'X' : '.'); 174 printf("\nProtocol: %u\n", e->ipv6.proto); 175 if (e->ipv6.flags & IP6T_F_TOS) 176 printf("TOS: %u\n", e->ipv6.tos); 177 printf("Flags: %02X\n", e->ipv6.flags); 178 printf("Invflags: %02X\n", e->ipv6.invflags); 179 printf("Counters: %llu packets, %llu bytes\n", 180 (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt); 181 printf("Cache: %08X\n", e->nfcache); 182 183 IP6T_MATCH_ITERATE(e, print_match); 184 185 t = ip6t_get_target(e); 186 printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size); 187 if (strcmp(t->u.user.name, IP6T_STANDARD_TARGET) == 0) { 188 const unsigned char *data = t->data; 189 int pos = *(const int *)data; 190 if (pos < 0) 191 printf("verdict=%s\n", 192 pos == -NF_ACCEPT-1 ? "NF_ACCEPT" 193 : pos == -NF_DROP-1 ? "NF_DROP" 194 : pos == IP6T_RETURN ? "RETURN" 195 : "UNKNOWN"); 196 else 197 printf("verdict=%u\n", pos); 198 } else if (strcmp(t->u.user.name, IP6T_ERROR_TARGET) == 0) 199 printf("error=`%s'\n", t->data); 200 201 printf("\n"); 202 return 0; 203} 204 205static unsigned char * 206is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, 207 unsigned char *matchmask) 208{ 209 unsigned int i; 210 unsigned char *mptr; 211 212 /* Always compare head structures: ignore mask here. */ 213 if (memcmp(&a->ipv6.src, &b->ipv6.src, sizeof(struct in6_addr)) 214 || memcmp(&a->ipv6.dst, &b->ipv6.dst, sizeof(struct in6_addr)) 215 || memcmp(&a->ipv6.smsk, &b->ipv6.smsk, sizeof(struct in6_addr)) 216 || memcmp(&a->ipv6.dmsk, &b->ipv6.dmsk, sizeof(struct in6_addr)) 217 || a->ipv6.proto != b->ipv6.proto 218 || a->ipv6.tos != b->ipv6.tos 219 || a->ipv6.flags != b->ipv6.flags 220 || a->ipv6.invflags != b->ipv6.invflags) 221 return NULL; 222 223 for (i = 0; i < IFNAMSIZ; i++) { 224 if (a->ipv6.iniface_mask[i] != b->ipv6.iniface_mask[i]) 225 return NULL; 226 if ((a->ipv6.iniface[i] & a->ipv6.iniface_mask[i]) 227 != (b->ipv6.iniface[i] & b->ipv6.iniface_mask[i])) 228 return NULL; 229 if (a->ipv6.outiface_mask[i] != b->ipv6.outiface_mask[i]) 230 return NULL; 231 if ((a->ipv6.outiface[i] & a->ipv6.outiface_mask[i]) 232 != (b->ipv6.outiface[i] & b->ipv6.outiface_mask[i])) 233 return NULL; 234 } 235 236 if (a->target_offset != b->target_offset 237 || a->next_offset != b->next_offset) 238 return NULL; 239 240 mptr = matchmask + sizeof(STRUCT_ENTRY); 241 if (IP6T_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr)) 242 return NULL; 243 mptr += IP6T_ALIGN(sizeof(struct ip6t_entry_target)); 244 245 return mptr; 246} 247 248/* All zeroes == unconditional rule. */ 249static inline int 250unconditional(const struct ip6t_ip6 *ipv6) 251{ 252 unsigned int i; 253 254 for (i = 0; i < sizeof(*ipv6); i++) 255 if (((char *)ipv6)[i]) 256 break; 257 258 return (i == sizeof(*ipv6)); 259} 260 261#ifdef IPTC_DEBUG 262/* Do every conceivable sanity check on the handle */ 263static void 264do_check(struct xtc_handle *h, unsigned int line) 265{ 266 unsigned int i, n; 267 unsigned int user_offset; /* Offset of first user chain */ 268 int was_return; 269 270 assert(h->changed == 0 || h->changed == 1); 271 if (strcmp(h->info.name, "filter") == 0) { 272 assert(h->info.valid_hooks 273 == (1 << NF_IP6_LOCAL_IN 274 | 1 << NF_IP6_FORWARD 275 | 1 << NF_IP6_LOCAL_OUT)); 276 277 /* Hooks should be first three */ 278 assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == 0); 279 280 n = get_chain_end(h, 0); 281 n += get_entry(h, n)->next_offset; 282 assert(h->info.hook_entry[NF_IP6_FORWARD] == n); 283 284 n = get_chain_end(h, n); 285 n += get_entry(h, n)->next_offset; 286 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n); 287 288 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT]; 289 } else if (strcmp(h->info.name, "nat") == 0) { 290 assert((h->info.valid_hooks 291 == (1 << NF_IP6_PRE_ROUTING 292 | 1 << NF_IP6_LOCAL_OUT 293 | 1 << NF_IP6_POST_ROUTING)) || 294 (h->info.valid_hooks 295 == (1 << NF_IP6_PRE_ROUTING 296 | 1 << NF_IP6_LOCAL_IN 297 | 1 << NF_IP6_LOCAL_OUT 298 | 1 << NF_IP6_POST_ROUTING))); 299 300 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0); 301 302 n = get_chain_end(h, 0); 303 304 n += get_entry(h, n)->next_offset; 305 assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n); 306 n = get_chain_end(h, n); 307 308 n += get_entry(h, n)->next_offset; 309 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n); 310 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT]; 311 312 if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) { 313 n = get_chain_end(h, n); 314 n += get_entry(h, n)->next_offset; 315 assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n); 316 user_offset = h->info.hook_entry[NF_IP6_LOCAL_IN]; 317 } 318 319 } else if (strcmp(h->info.name, "mangle") == 0) { 320 /* This code is getting ugly because linux < 2.4.18-pre6 had 321 * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks 322 * */ 323 assert((h->info.valid_hooks 324 == (1 << NF_IP6_PRE_ROUTING 325 | 1 << NF_IP6_LOCAL_OUT)) || 326 (h->info.valid_hooks 327 == (1 << NF_IP6_PRE_ROUTING 328 | 1 << NF_IP6_LOCAL_IN 329 | 1 << NF_IP6_FORWARD 330 | 1 << NF_IP6_LOCAL_OUT 331 | 1 << NF_IP6_POST_ROUTING))); 332 333 /* Hooks should be first five */ 334 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0); 335 336 n = get_chain_end(h, 0); 337 338 if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) { 339 n += get_entry(h, n)->next_offset; 340 assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n); 341 n = get_chain_end(h, n); 342 } 343 344 if (h->info.valid_hooks & (1 << NF_IP6_FORWARD)) { 345 n += get_entry(h, n)->next_offset; 346 assert(h->info.hook_entry[NF_IP6_FORWARD] == n); 347 n = get_chain_end(h, n); 348 } 349 350 n += get_entry(h, n)->next_offset; 351 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n); 352 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT]; 353 354 if (h->info.valid_hooks & (1 << NF_IP6_POST_ROUTING)) { 355 n = get_chain_end(h, n); 356 n += get_entry(h, n)->next_offset; 357 assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n); 358 user_offset = h->info.hook_entry[NF_IP6_POST_ROUTING]; 359 } 360 } else if (strcmp(h->info.name, "raw") == 0) { 361 assert(h->info.valid_hooks 362 == (1 << NF_IP6_PRE_ROUTING 363 | 1 << NF_IP6_LOCAL_OUT)); 364 365 /* Hooks should be first three */ 366 assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0); 367 368 n = get_chain_end(h, n); 369 n += get_entry(h, n)->next_offset; 370 assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n); 371 372 user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT]; 373 } else { 374 fprintf(stderr, "Unknown table `%s'\n", h->info.name); 375 abort(); 376 } 377 378 /* User chain == end of last builtin + policy entry */ 379 user_offset = get_chain_end(h, user_offset); 380 user_offset += get_entry(h, user_offset)->next_offset; 381 382 /* Overflows should be end of entry chains, and unconditional 383 policy nodes. */ 384 for (i = 0; i < NUMHOOKS; i++) { 385 STRUCT_ENTRY *e; 386 STRUCT_STANDARD_TARGET *t; 387 388 if (!(h->info.valid_hooks & (1 << i))) 389 continue; 390 assert(h->info.underflow[i] 391 == get_chain_end(h, h->info.hook_entry[i])); 392 393 e = get_entry(h, get_chain_end(h, h->info.hook_entry[i])); 394 assert(unconditional(&e->ipv6)); 395 assert(e->target_offset == sizeof(*e)); 396 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e); 397 printf("target_size=%u, align=%u\n", 398 t->target.u.target_size, ALIGN(sizeof(*t))); 399 assert(t->target.u.target_size == ALIGN(sizeof(*t))); 400 assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t))); 401 402 assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0); 403 assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1); 404 405 /* Hooks and underflows must be valid entries */ 406 iptcb_entry2index(h, get_entry(h, h->info.hook_entry[i])); 407 iptcb_entry2index(h, get_entry(h, h->info.underflow[i])); 408 } 409 410 assert(h->info.size 411 >= h->info.num_entries * (sizeof(STRUCT_ENTRY) 412 +sizeof(STRUCT_STANDARD_TARGET))); 413 414 assert(h->entries.size 415 >= (h->new_number 416 * (sizeof(STRUCT_ENTRY) 417 + sizeof(STRUCT_STANDARD_TARGET)))); 418 assert(strcmp(h->info.name, h->entries.name) == 0); 419 420 i = 0; n = 0; 421 was_return = 0; 422 423#if 0 424 /* Check all the entries. */ 425 ENTRY_ITERATE(h->entries.entrytable, h->entries.size, 426 check_entry, &i, &n, user_offset, &was_return, h); 427 428 assert(i == h->new_number); 429 assert(n == h->entries.size); 430 431 /* Final entry must be error node */ 432 assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1)) 433 ->u.user.name, 434 ERROR_TARGET) == 0); 435#endif 436} 437#endif /*IPTC_DEBUG*/ 438