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
99 #define TC_IPPROTO IPPROTO_IP
101 #define SO_SET_REPLACE IPT_SO_SET_REPLACE
102 #define SO_SET_ADD_COUNTERS IPT_SO_SET_ADD_COUNTERS
103 #define SO_GET_INFO IPT_SO_GET_INFO
104 #define SO_GET_ENTRIES IPT_SO_GET_ENTRIES
105 #define SO_GET_VERSION IPT_SO_GET_VERSION
107 #define STANDARD_TARGET IPT_STANDARD_TARGET
108 #define LABEL_RETURN IPTC_LABEL_RETURN
109 #define LABEL_ACCEPT IPTC_LABEL_ACCEPT
110 #define LABEL_DROP IPTC_LABEL_DROP
111 #define LABEL_QUEUE IPTC_LABEL_QUEUE
113 #define ALIGN IPT_ALIGN
114 #define RETURN IPT_RETURN
118 #define IP_PARTS_NATIVE(n) \
119 (unsigned int)((n)>>24)&0xFF, \
120 (unsigned int)((n)>>16)&0xFF, \
121 (unsigned int)((n)>>8)&0xFF, \
122 (unsigned int)((n)&0xFF)
124 #define IP_PARTS(n) IP_PARTS_NATIVE(ntohl(n))
127 dump_entry(STRUCT_ENTRY *e, const TC_HANDLE_T handle)
130 STRUCT_ENTRY_TARGET *t;
132 printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
133 iptcb_entry2offset(handle, e));
134 printf("SRC IP: %u.%u.%u.%u/%u.%u.%u.%u\n",
135 IP_PARTS(e->ip.src.s_addr),IP_PARTS(e->ip.smsk.s_addr));
136 printf("DST IP: %u.%u.%u.%u/%u.%u.%u.%u\n",
137 IP_PARTS(e->ip.dst.s_addr),IP_PARTS(e->ip.dmsk.s_addr));
138 printf("Interface: `%s'/", e->ip.iniface);
139 for (i = 0; i < IFNAMSIZ; i++)
140 printf("%c", e->ip.iniface_mask[i] ? 'X' : '.');
141 printf("to `%s'/", e->ip.outiface);
142 for (i = 0; i < IFNAMSIZ; i++)
143 printf("%c", e->ip.outiface_mask[i] ? 'X' : '.');
144 printf("\nProtocol: %u\n", e->ip.proto);
145 printf("Flags: %02X\n", e->ip.flags);
146 printf("Invflags: %02X\n", e->ip.invflags);
147 printf("Counters: %llu packets, %llu bytes\n",
148 (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
149 printf("Cache: %08X ", e->nfcache);
150 if (e->nfcache & NFC_ALTERED) printf("ALTERED ");
151 if (e->nfcache & NFC_UNKNOWN) printf("UNKNOWN ");
154 IPT_MATCH_ITERATE(e, print_match);
157 printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
158 if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) {
159 int pos = *(int *)t->data;
161 printf("verdict=%s\n",
162 pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
163 : pos == -NF_DROP-1 ? "NF_DROP"
164 : pos == -NF_QUEUE-1 ? "NF_QUEUE"
165 : pos == RETURN ? "RETURN"
168 printf("verdict=%u\n", pos);
169 } else if (strcmp(t->u.user.name, IPT_ERROR_TARGET) == 0)
170 printf("error=`%s'\n", t->data);
176 static unsigned char *
177 is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, unsigned char *matchmask)
182 /* Always compare head structures: ignore mask here. */
183 if (a->ip.src.s_addr != b->ip.src.s_addr
184 || a->ip.dst.s_addr != b->ip.dst.s_addr
185 || a->ip.smsk.s_addr != b->ip.smsk.s_addr
186 || a->ip.dmsk.s_addr != b->ip.dmsk.s_addr
187 || a->ip.proto != b->ip.proto
188 || a->ip.flags != b->ip.flags
189 || a->ip.invflags != b->ip.invflags)
192 for (i = 0; i < IFNAMSIZ; i++) {
193 if (a->ip.iniface_mask[i] != b->ip.iniface_mask[i])
195 if ((a->ip.iniface[i] & a->ip.iniface_mask[i])
196 != (b->ip.iniface[i] & b->ip.iniface_mask[i]))
198 if (a->ip.outiface_mask[i] != b->ip.outiface_mask[i])
200 if ((a->ip.outiface[i] & a->ip.outiface_mask[i])
201 != (b->ip.outiface[i] & b->ip.outiface_mask[i]))
205 if (a->nfcache != b->nfcache
206 || a->target_offset != b->target_offset
207 || a->next_offset != b->next_offset)
210 mptr = matchmask + sizeof(STRUCT_ENTRY);
211 if (IPT_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
213 mptr += IPT_ALIGN(sizeof(struct ipt_entry_target));
219 /***************************** DEBUGGING ********************************/
221 unconditional(const struct ipt_ip *ip)
225 for (i = 0; i < sizeof(*ip)/sizeof(u_int32_t); i++)
226 if (((u_int32_t *)ip)[i])
233 check_match(const STRUCT_ENTRY_MATCH *m, unsigned int *off)
235 assert(m->u.match_size >= sizeof(STRUCT_ENTRY_MATCH));
236 assert(ALIGN(m->u.match_size) == m->u.match_size);
238 (*off) += m->u.match_size;
243 check_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off,
244 unsigned int user_offset, int *was_return,
248 STRUCT_STANDARD_TARGET *t;
250 assert(e->target_offset >= sizeof(STRUCT_ENTRY));
251 assert(e->next_offset >= e->target_offset
252 + sizeof(STRUCT_ENTRY_TARGET));
253 toff = sizeof(STRUCT_ENTRY);
254 IPT_MATCH_ITERATE(e, check_match, &toff);
256 assert(toff == e->target_offset);
258 t = (STRUCT_STANDARD_TARGET *)
259 GET_TARGET((STRUCT_ENTRY *)e);
260 /* next_offset will have to be multiple of entry alignment. */
261 assert(e->next_offset == ALIGN(e->next_offset));
262 assert(e->target_offset == ALIGN(e->target_offset));
263 assert(t->target.u.target_size == ALIGN(t->target.u.target_size));
264 assert(!TC_IS_CHAIN(t->target.u.user.name, h));
266 if (strcmp(t->target.u.user.name, STANDARD_TARGET) == 0) {
267 assert(t->target.u.target_size
268 == ALIGN(sizeof(STRUCT_STANDARD_TARGET)));
270 assert(t->verdict == -NF_DROP-1
271 || t->verdict == -NF_ACCEPT-1
272 || t->verdict == RETURN
273 || t->verdict < (int)h->entries->size);
275 if (t->verdict >= 0) {
276 STRUCT_ENTRY *te = get_entry(h, t->verdict);
279 idx = iptcb_entry2index(h, te);
280 assert(strcmp(GET_TARGET(te)->u.user.name,
285 /* Prior node must be error node, or this node. */
286 assert(t->verdict == iptcb_entry2offset(h, e)+e->next_offset
287 || strcmp(GET_TARGET(index2entry(h, idx-1))
288 ->u.user.name, IPT_ERROR_TARGET)
292 if (t->verdict == RETURN
293 && unconditional(&e->ip)
294 && e->target_offset == sizeof(*e))
298 } else if (strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0) {
299 assert(t->target.u.target_size
300 == ALIGN(sizeof(struct ipt_error_target)));
302 /* If this is in user area, previous must have been return */
303 if (*off > user_offset)
308 else *was_return = 0;
310 if (*off == user_offset)
311 assert(strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0);
313 (*off) += e->next_offset;
319 /* Do every conceivable sanity check on the handle */
321 do_check(TC_HANDLE_T h, unsigned int line)
324 unsigned int user_offset; /* Offset of first user chain */
327 assert(h->changed == 0 || h->changed == 1);
328 if (strcmp(h->info.name, "filter") == 0) {
329 assert(h->info.valid_hooks
330 == (1 << NF_IP_LOCAL_IN
332 | 1 << NF_IP_LOCAL_OUT));
334 /* Hooks should be first three */
335 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == 0);
337 n = get_chain_end(h, 0);
338 n += get_entry(h, n)->next_offset;
339 assert(h->info.hook_entry[NF_IP_FORWARD] == n);
341 n = get_chain_end(h, n);
342 n += get_entry(h, n)->next_offset;
343 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
345 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
346 } else if (strcmp(h->info.name, "nat") == 0) {
347 assert((h->info.valid_hooks
348 == (1 << NF_IP_PRE_ROUTING
349 | 1 << NF_IP_POST_ROUTING
350 | 1 << NF_IP_LOCAL_OUT)) ||
352 == (1 << NF_IP_PRE_ROUTING
353 | 1 << NF_IP_LOCAL_IN
354 | 1 << NF_IP_POST_ROUTING
355 | 1 << NF_IP_LOCAL_OUT)));
357 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
359 n = get_chain_end(h, 0);
361 n += get_entry(h, n)->next_offset;
362 assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
363 n = get_chain_end(h, n);
365 n += get_entry(h, n)->next_offset;
366 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
367 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
369 if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
370 n = get_chain_end(h, n);
371 n += get_entry(h, n)->next_offset;
372 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
373 user_offset = h->info.hook_entry[NF_IP_LOCAL_IN];
376 } else if (strcmp(h->info.name, "mangle") == 0) {
377 /* This code is getting ugly because linux < 2.4.18-pre6 had
378 * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
380 assert((h->info.valid_hooks
381 == (1 << NF_IP_PRE_ROUTING
382 | 1 << NF_IP_LOCAL_OUT)) ||
384 == (1 << NF_IP_PRE_ROUTING
385 | 1 << NF_IP_LOCAL_IN
387 | 1 << NF_IP_LOCAL_OUT
388 | 1 << NF_IP_POST_ROUTING)));
390 /* Hooks should be first five */
391 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
393 n = get_chain_end(h, 0);
395 if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
396 n += get_entry(h, n)->next_offset;
397 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
398 n = get_chain_end(h, n);
401 if (h->info.valid_hooks & (1 << NF_IP_FORWARD)) {
402 n += get_entry(h, n)->next_offset;
403 assert(h->info.hook_entry[NF_IP_FORWARD] == n);
404 n = get_chain_end(h, n);
407 n += get_entry(h, n)->next_offset;
408 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
409 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
411 if (h->info.valid_hooks & (1 << NF_IP_POST_ROUTING)) {
412 n = get_chain_end(h, n);
413 n += get_entry(h, n)->next_offset;
414 assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
415 user_offset = h->info.hook_entry[NF_IP_POST_ROUTING];
417 } else if (strcmp(h->info.name, "raw") == 0) {
418 assert(h->info.valid_hooks
419 == (1 << NF_IP_PRE_ROUTING
420 | 1 << NF_IP_LOCAL_OUT));
422 /* Hooks should be first three */
423 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
425 n = get_chain_end(h, n);
426 n += get_entry(h, n)->next_offset;
427 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
429 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
431 #ifdef NF_IP_DROPPING
432 } else if (strcmp(h->info.name, "drop") == 0) {
433 assert(h->info.valid_hooks == (1 << NF_IP_DROPPING));
435 /* Hook should be first */
436 assert(h->info.hook_entry[NF_IP_DROPPING] == 0);
440 fprintf(stderr, "Unknown table `%s'\n", h->info.name);
444 /* User chain == end of last builtin + policy entry */
445 user_offset = get_chain_end(h, user_offset);
446 user_offset += get_entry(h, user_offset)->next_offset;
448 /* Overflows should be end of entry chains, and unconditional
450 for (i = 0; i < NUMHOOKS; i++) {
452 STRUCT_STANDARD_TARGET *t;
454 if (!(h->info.valid_hooks & (1 << i)))
456 assert(h->info.underflow[i]
457 == get_chain_end(h, h->info.hook_entry[i]));
459 e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
460 assert(unconditional(&e->ip));
461 assert(e->target_offset == sizeof(*e));
462 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
463 assert(t->target.u.target_size == ALIGN(sizeof(*t)));
464 assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
466 assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
467 assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
469 /* Hooks and underflows must be valid entries */
470 entry2index(h, get_entry(h, h->info.hook_entry[i]));
471 entry2index(h, get_entry(h, h->info.underflow[i]));
475 >= h->info.num_entries * (sizeof(STRUCT_ENTRY)
476 +sizeof(STRUCT_STANDARD_TARGET)));
478 assert(h->entries.size
480 * (sizeof(STRUCT_ENTRY)
481 + sizeof(STRUCT_STANDARD_TARGET))));
482 assert(strcmp(h->info.name, h->entries.name) == 0);
486 /* Check all the entries. */
487 ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
488 check_entry, &i, &n, user_offset, &was_return, h);
490 assert(i == h->new_number);
491 assert(n == h->entries.size);
493 /* Final entry must be error node */
494 assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
498 #endif /*IPTC_DEBUG*/