1 /* Library which manipulates firewall rules. Version 0.1. */
3 /* Architecture of firewall rules is as follows:
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.
11 /* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See
12 COPYING for details). */
21 #ifdef DEBUG_CONNTRACK
25 #if !defined(__GLIBC__) || (__GLIBC__ < 2)
26 typedef unsigned int socklen_t;
29 #include "libiptc/libiptc.h"
32 #define IP_OFFSET 0x1FFF
34 #define HOOK_PRE_ROUTING NF_IP_PRE_ROUTING
35 #define HOOK_LOCAL_IN NF_IP_LOCAL_IN
36 #define HOOK_FORWARD NF_IP_FORWARD
37 #define HOOK_LOCAL_OUT NF_IP_LOCAL_OUT
38 #define HOOK_POST_ROUTING NF_IP_POST_ROUTING
40 #define HOOK_DROPPING NF_IP_DROPPING
43 #define STRUCT_ENTRY_TARGET struct ipt_entry_target
44 #define STRUCT_ENTRY struct ipt_entry
45 #define STRUCT_ENTRY_MATCH struct ipt_entry_match
46 #define STRUCT_GETINFO struct ipt_getinfo
47 #define STRUCT_GET_ENTRIES struct ipt_get_entries
48 #define STRUCT_COUNTERS struct ipt_counters
49 #define STRUCT_COUNTERS_INFO struct ipt_counters_info
50 #define STRUCT_STANDARD_TARGET struct ipt_standard_target
51 #define STRUCT_REPLACE struct ipt_replace
53 #define STRUCT_TC_HANDLE struct iptc_handle
54 #define TC_HANDLE_T iptc_handle_t
56 #define ENTRY_ITERATE IPT_ENTRY_ITERATE
57 #define TABLE_MAXNAMELEN IPT_TABLE_MAXNAMELEN
58 #define FUNCTION_MAXNAMELEN IPT_FUNCTION_MAXNAMELEN
60 #define GET_TARGET ipt_get_target
62 #define ERROR_TARGET IPT_ERROR_TARGET
63 #define NUMHOOKS NF_IP_NUMHOOKS
65 #define IPT_CHAINLABEL ipt_chainlabel
67 #define TC_DUMP_ENTRIES dump_entries
68 #define TC_IS_CHAIN iptc_is_chain
69 #define TC_FIRST_CHAIN iptc_first_chain
70 #define TC_NEXT_CHAIN iptc_next_chain
71 #define TC_FIRST_RULE iptc_first_rule
72 #define TC_NEXT_RULE iptc_next_rule
73 #define TC_GET_TARGET iptc_get_target
74 #define TC_BUILTIN iptc_builtin
75 #define TC_GET_POLICY iptc_get_policy
76 #define TC_INSERT_ENTRY iptc_insert_entry
77 #define TC_REPLACE_ENTRY iptc_replace_entry
78 #define TC_APPEND_ENTRY iptc_append_entry
79 #define TC_DELETE_ENTRY iptc_delete_entry
80 #define TC_DELETE_NUM_ENTRY iptc_delete_num_entry
81 #define TC_CHECK_PACKET iptc_check_packet
82 #define TC_FLUSH_ENTRIES iptc_flush_entries
83 #define TC_ZERO_ENTRIES iptc_zero_entries
84 #define TC_READ_COUNTER iptc_read_counter
85 #define TC_ZERO_COUNTER iptc_zero_counter
86 #define TC_SET_COUNTER iptc_set_counter
87 #define TC_CREATE_CHAIN iptc_create_chain
88 #define TC_GET_REFERENCES iptc_get_references
89 #define TC_DELETE_CHAIN iptc_delete_chain
90 #define TC_RENAME_CHAIN iptc_rename_chain
91 #define TC_SET_POLICY iptc_set_policy
92 #define TC_GET_RAW_SOCKET iptc_get_raw_socket
93 #define TC_INIT iptc_init
94 #define TC_FREE iptc_free
95 #define TC_COMMIT iptc_commit
96 #define TC_STRERROR iptc_strerror
97 #define TC_NUM_RULES iptc_num_rules
98 #define TC_GET_RULE iptc_get_rule
100 #define TC_AF AF_INET
101 #define TC_IPPROTO IPPROTO_IP
103 #define SO_SET_REPLACE IPT_SO_SET_REPLACE
104 #define SO_SET_ADD_COUNTERS IPT_SO_SET_ADD_COUNTERS
105 #define SO_GET_INFO IPT_SO_GET_INFO
106 #define SO_GET_ENTRIES IPT_SO_GET_ENTRIES
107 #define SO_GET_VERSION IPT_SO_GET_VERSION
109 #define STANDARD_TARGET IPT_STANDARD_TARGET
110 #define LABEL_RETURN IPTC_LABEL_RETURN
111 #define LABEL_ACCEPT IPTC_LABEL_ACCEPT
112 #define LABEL_DROP IPTC_LABEL_DROP
113 #define LABEL_QUEUE IPTC_LABEL_QUEUE
115 #define ALIGN IPT_ALIGN
116 #define RETURN IPT_RETURN
120 #define IP_PARTS_NATIVE(n) \
121 (unsigned int)((n)>>24)&0xFF, \
122 (unsigned int)((n)>>16)&0xFF, \
123 (unsigned int)((n)>>8)&0xFF, \
124 (unsigned int)((n)&0xFF)
126 #define IP_PARTS(n) IP_PARTS_NATIVE(ntohl(n))
129 dump_entry(STRUCT_ENTRY *e, const TC_HANDLE_T handle)
132 STRUCT_ENTRY_TARGET *t;
134 printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
135 iptcb_entry2offset(handle, e));
136 printf("SRC IP: %u.%u.%u.%u/%u.%u.%u.%u\n",
137 IP_PARTS(e->ip.src.s_addr),IP_PARTS(e->ip.smsk.s_addr));
138 printf("DST IP: %u.%u.%u.%u/%u.%u.%u.%u\n",
139 IP_PARTS(e->ip.dst.s_addr),IP_PARTS(e->ip.dmsk.s_addr));
140 printf("Interface: `%s'/", e->ip.iniface);
141 for (i = 0; i < IFNAMSIZ; i++)
142 printf("%c", e->ip.iniface_mask[i] ? 'X' : '.');
143 printf("to `%s'/", e->ip.outiface);
144 for (i = 0; i < IFNAMSIZ; i++)
145 printf("%c", e->ip.outiface_mask[i] ? 'X' : '.');
146 printf("\nProtocol: %u\n", e->ip.proto);
147 printf("Flags: %02X\n", e->ip.flags);
148 printf("Invflags: %02X\n", e->ip.invflags);
149 printf("Counters: %llu packets, %llu bytes\n",
150 (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
151 printf("Cache: %08X\n", e->nfcache);
153 IPT_MATCH_ITERATE(e, print_match);
156 printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
157 if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) {
158 int pos = *(int *)t->data;
160 printf("verdict=%s\n",
161 pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
162 : pos == -NF_DROP-1 ? "NF_DROP"
163 : pos == -NF_QUEUE-1 ? "NF_QUEUE"
164 : pos == RETURN ? "RETURN"
167 printf("verdict=%u\n", pos);
168 } else if (strcmp(t->u.user.name, IPT_ERROR_TARGET) == 0)
169 printf("error=`%s'\n", t->data);
175 static unsigned char *
176 is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, unsigned char *matchmask)
181 /* Always compare head structures: ignore mask here. */
182 if (a->ip.src.s_addr != b->ip.src.s_addr
183 || a->ip.dst.s_addr != b->ip.dst.s_addr
184 || a->ip.smsk.s_addr != b->ip.smsk.s_addr
185 || a->ip.dmsk.s_addr != b->ip.dmsk.s_addr
186 || a->ip.proto != b->ip.proto
187 || a->ip.flags != b->ip.flags
188 || a->ip.invflags != b->ip.invflags)
191 for (i = 0; i < IFNAMSIZ; i++) {
192 if (a->ip.iniface_mask[i] != b->ip.iniface_mask[i])
194 if ((a->ip.iniface[i] & a->ip.iniface_mask[i])
195 != (b->ip.iniface[i] & b->ip.iniface_mask[i]))
197 if (a->ip.outiface_mask[i] != b->ip.outiface_mask[i])
199 if ((a->ip.outiface[i] & a->ip.outiface_mask[i])
200 != (b->ip.outiface[i] & b->ip.outiface_mask[i]))
204 if (a->target_offset != b->target_offset
205 || a->next_offset != b->next_offset)
208 mptr = matchmask + sizeof(STRUCT_ENTRY);
209 if (IPT_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
211 mptr += IPT_ALIGN(sizeof(struct ipt_entry_target));
217 /***************************** DEBUGGING ********************************/
219 unconditional(const struct ipt_ip *ip)
223 for (i = 0; i < sizeof(*ip)/sizeof(u_int32_t); i++)
224 if (((u_int32_t *)ip)[i])
231 check_match(const STRUCT_ENTRY_MATCH *m, unsigned int *off)
233 assert(m->u.match_size >= sizeof(STRUCT_ENTRY_MATCH));
234 assert(ALIGN(m->u.match_size) == m->u.match_size);
236 (*off) += m->u.match_size;
241 check_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off,
242 unsigned int user_offset, int *was_return,
246 STRUCT_STANDARD_TARGET *t;
248 assert(e->target_offset >= sizeof(STRUCT_ENTRY));
249 assert(e->next_offset >= e->target_offset
250 + sizeof(STRUCT_ENTRY_TARGET));
251 toff = sizeof(STRUCT_ENTRY);
252 IPT_MATCH_ITERATE(e, check_match, &toff);
254 assert(toff == e->target_offset);
256 t = (STRUCT_STANDARD_TARGET *)
257 GET_TARGET((STRUCT_ENTRY *)e);
258 /* next_offset will have to be multiple of entry alignment. */
259 assert(e->next_offset == ALIGN(e->next_offset));
260 assert(e->target_offset == ALIGN(e->target_offset));
261 assert(t->target.u.target_size == ALIGN(t->target.u.target_size));
262 assert(!TC_IS_CHAIN(t->target.u.user.name, h));
264 if (strcmp(t->target.u.user.name, STANDARD_TARGET) == 0) {
265 assert(t->target.u.target_size
266 == ALIGN(sizeof(STRUCT_STANDARD_TARGET)));
268 assert(t->verdict == -NF_DROP-1
269 || t->verdict == -NF_ACCEPT-1
270 || t->verdict == RETURN
271 || t->verdict < (int)h->entries->size);
273 if (t->verdict >= 0) {
274 STRUCT_ENTRY *te = get_entry(h, t->verdict);
277 idx = iptcb_entry2index(h, te);
278 assert(strcmp(GET_TARGET(te)->u.user.name,
283 /* Prior node must be error node, or this node. */
284 assert(t->verdict == iptcb_entry2offset(h, e)+e->next_offset
285 || strcmp(GET_TARGET(index2entry(h, idx-1))
286 ->u.user.name, IPT_ERROR_TARGET)
290 if (t->verdict == RETURN
291 && unconditional(&e->ip)
292 && e->target_offset == sizeof(*e))
296 } else if (strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0) {
297 assert(t->target.u.target_size
298 == ALIGN(sizeof(struct ipt_error_target)));
300 /* If this is in user area, previous must have been return */
301 if (*off > user_offset)
306 else *was_return = 0;
308 if (*off == user_offset)
309 assert(strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0);
311 (*off) += e->next_offset;
317 /* Do every conceivable sanity check on the handle */
319 do_check(TC_HANDLE_T h, unsigned int line)
322 unsigned int user_offset; /* Offset of first user chain */
325 assert(h->changed == 0 || h->changed == 1);
326 if (strcmp(h->info.name, "filter") == 0) {
327 assert(h->info.valid_hooks
328 == (1 << NF_IP_LOCAL_IN
330 | 1 << NF_IP_LOCAL_OUT));
332 /* Hooks should be first three */
333 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == 0);
335 n = get_chain_end(h, 0);
336 n += get_entry(h, n)->next_offset;
337 assert(h->info.hook_entry[NF_IP_FORWARD] == n);
339 n = get_chain_end(h, n);
340 n += get_entry(h, n)->next_offset;
341 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
343 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
344 } else if (strcmp(h->info.name, "nat") == 0) {
345 assert((h->info.valid_hooks
346 == (1 << NF_IP_PRE_ROUTING
347 | 1 << NF_IP_POST_ROUTING
348 | 1 << NF_IP_LOCAL_OUT)) ||
350 == (1 << NF_IP_PRE_ROUTING
351 | 1 << NF_IP_LOCAL_IN
352 | 1 << NF_IP_POST_ROUTING
353 | 1 << NF_IP_LOCAL_OUT)));
355 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
357 n = get_chain_end(h, 0);
359 n += get_entry(h, n)->next_offset;
360 assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
361 n = get_chain_end(h, n);
363 n += get_entry(h, n)->next_offset;
364 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
365 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
367 if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
368 n = get_chain_end(h, n);
369 n += get_entry(h, n)->next_offset;
370 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
371 user_offset = h->info.hook_entry[NF_IP_LOCAL_IN];
374 } else if (strcmp(h->info.name, "mangle") == 0) {
375 /* This code is getting ugly because linux < 2.4.18-pre6 had
376 * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
378 assert((h->info.valid_hooks
379 == (1 << NF_IP_PRE_ROUTING
380 | 1 << NF_IP_LOCAL_OUT)) ||
382 == (1 << NF_IP_PRE_ROUTING
383 | 1 << NF_IP_LOCAL_IN
385 | 1 << NF_IP_LOCAL_OUT
386 | 1 << NF_IP_POST_ROUTING)));
388 /* Hooks should be first five */
389 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
391 n = get_chain_end(h, 0);
393 if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
394 n += get_entry(h, n)->next_offset;
395 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
396 n = get_chain_end(h, n);
399 if (h->info.valid_hooks & (1 << NF_IP_FORWARD)) {
400 n += get_entry(h, n)->next_offset;
401 assert(h->info.hook_entry[NF_IP_FORWARD] == n);
402 n = get_chain_end(h, n);
405 n += get_entry(h, n)->next_offset;
406 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
407 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
409 if (h->info.valid_hooks & (1 << NF_IP_POST_ROUTING)) {
410 n = get_chain_end(h, n);
411 n += get_entry(h, n)->next_offset;
412 assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
413 user_offset = h->info.hook_entry[NF_IP_POST_ROUTING];
415 } else if (strcmp(h->info.name, "raw") == 0) {
416 assert(h->info.valid_hooks
417 == (1 << NF_IP_PRE_ROUTING
418 | 1 << NF_IP_LOCAL_OUT));
420 /* Hooks should be first three */
421 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
423 n = get_chain_end(h, n);
424 n += get_entry(h, n)->next_offset;
425 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
427 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
429 #ifdef NF_IP_DROPPING
430 } else if (strcmp(h->info.name, "drop") == 0) {
431 assert(h->info.valid_hooks == (1 << NF_IP_DROPPING));
433 /* Hook should be first */
434 assert(h->info.hook_entry[NF_IP_DROPPING] == 0);
438 fprintf(stderr, "Unknown table `%s'\n", h->info.name);
442 /* User chain == end of last builtin + policy entry */
443 user_offset = get_chain_end(h, user_offset);
444 user_offset += get_entry(h, user_offset)->next_offset;
446 /* Overflows should be end of entry chains, and unconditional
448 for (i = 0; i < NUMHOOKS; i++) {
450 STRUCT_STANDARD_TARGET *t;
452 if (!(h->info.valid_hooks & (1 << i)))
454 assert(h->info.underflow[i]
455 == get_chain_end(h, h->info.hook_entry[i]));
457 e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
458 assert(unconditional(&e->ip));
459 assert(e->target_offset == sizeof(*e));
460 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
461 assert(t->target.u.target_size == ALIGN(sizeof(*t)));
462 assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
464 assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
465 assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
467 /* Hooks and underflows must be valid entries */
468 entry2index(h, get_entry(h, h->info.hook_entry[i]));
469 entry2index(h, get_entry(h, h->info.underflow[i]));
473 >= h->info.num_entries * (sizeof(STRUCT_ENTRY)
474 +sizeof(STRUCT_STANDARD_TARGET)));
476 assert(h->entries.size
478 * (sizeof(STRUCT_ENTRY)
479 + sizeof(STRUCT_STANDARD_TARGET))));
480 assert(strcmp(h->info.name, h->entries.name) == 0);
484 /* Check all the entries. */
485 ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
486 check_entry, &i, &n, user_offset, &was_return, h);
488 assert(i == h->new_number);
489 assert(n == h->entries.size);
491 /* Final entry must be error node */
492 assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
496 #endif /*IPTC_DEBUG*/