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", entry2index(handle, e),
133 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 e->counters.pcnt, 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 ");
152 if (e->nfcache & NFC_IP_SRC) printf("IP_SRC ");
153 if (e->nfcache & NFC_IP_DST) printf("IP_DST ");
154 if (e->nfcache & NFC_IP_IF_IN) printf("IP_IF_IN ");
155 if (e->nfcache & NFC_IP_IF_OUT) printf("IP_IF_OUT ");
156 if (e->nfcache & NFC_IP_TOS) printf("IP_TOS ");
157 if (e->nfcache & NFC_IP_PROTO) printf("IP_PROTO ");
158 if (e->nfcache & NFC_IP_OPTIONS) printf("IP_OPTIONS ");
159 if (e->nfcache & NFC_IP_TCPFLAGS) printf("IP_TCPFLAGS ");
160 if (e->nfcache & NFC_IP_SRC_PT) printf("IP_SRC_PT ");
161 if (e->nfcache & NFC_IP_DST_PT) printf("IP_DST_PT ");
162 if (e->nfcache & NFC_IP_PROTO_UNKNOWN) printf("IP_PROTO_UNKNOWN ");
165 IPT_MATCH_ITERATE(e, print_match);
168 printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
169 if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) {
170 int pos = *(int *)t->data;
172 printf("verdict=%s\n",
173 pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
174 : pos == -NF_DROP-1 ? "NF_DROP"
175 : pos == -NF_QUEUE-1 ? "NF_QUEUE"
176 : pos == RETURN ? "RETURN"
179 printf("verdict=%u\n", pos);
180 } else if (strcmp(t->u.user.name, IPT_ERROR_TARGET) == 0)
181 printf("error=`%s'\n", t->data);
188 is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, unsigned char *matchmask)
191 STRUCT_ENTRY_TARGET *ta, *tb;
194 /* Always compare head structures: ignore mask here. */
195 if (a->ip.src.s_addr != b->ip.src.s_addr
196 || a->ip.dst.s_addr != b->ip.dst.s_addr
197 || a->ip.smsk.s_addr != b->ip.smsk.s_addr
198 || a->ip.dmsk.s_addr != b->ip.dmsk.s_addr
199 || a->ip.proto != b->ip.proto
200 || a->ip.flags != b->ip.flags
201 || a->ip.invflags != b->ip.invflags)
204 for (i = 0; i < IFNAMSIZ; i++) {
205 if (a->ip.iniface_mask[i] != b->ip.iniface_mask[i])
207 if ((a->ip.iniface[i] & a->ip.iniface_mask[i])
208 != (b->ip.iniface[i] & b->ip.iniface_mask[i]))
210 if (a->ip.outiface_mask[i] != b->ip.outiface_mask[i])
212 if ((a->ip.outiface[i] & a->ip.outiface_mask[i])
213 != (b->ip.outiface[i] & b->ip.outiface_mask[i]))
217 if (a->nfcache != b->nfcache
218 || a->target_offset != b->target_offset
219 || a->next_offset != b->next_offset)
222 mptr = matchmask + sizeof(STRUCT_ENTRY);
223 if (IPT_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
226 ta = GET_TARGET((STRUCT_ENTRY *)a);
227 tb = GET_TARGET((STRUCT_ENTRY *)b);
228 if (ta->u.target_size != tb->u.target_size)
230 if (strcmp(ta->u.user.name, tb->u.user.name) != 0)
234 if (target_different(ta->data, tb->data,
235 ta->u.target_size - sizeof(*ta), mptr))
241 /***************************** DEBUGGING ********************************/
243 unconditional(const struct ipt_ip *ip)
247 for (i = 0; i < sizeof(*ip)/sizeof(u_int32_t); i++)
248 if (((u_int32_t *)ip)[i])
255 check_match(const STRUCT_ENTRY_MATCH *m, unsigned int *off)
257 assert(m->u.match_size >= sizeof(STRUCT_ENTRY_MATCH));
258 assert(ALIGN(m->u.match_size) == m->u.match_size);
260 (*off) += m->u.match_size;
265 check_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off,
266 unsigned int user_offset, int *was_return,
270 STRUCT_STANDARD_TARGET *t;
272 assert(e->target_offset >= sizeof(STRUCT_ENTRY));
273 assert(e->next_offset >= e->target_offset
274 + sizeof(STRUCT_ENTRY_TARGET));
275 toff = sizeof(STRUCT_ENTRY);
276 IPT_MATCH_ITERATE(e, check_match, &toff);
278 assert(toff == e->target_offset);
280 t = (STRUCT_STANDARD_TARGET *)
281 GET_TARGET((STRUCT_ENTRY *)e);
282 /* next_offset will have to be multiple of entry alignment. */
283 assert(e->next_offset == ALIGN(e->next_offset));
284 assert(e->target_offset == ALIGN(e->target_offset));
285 assert(t->target.u.target_size == ALIGN(t->target.u.target_size));
286 assert(!TC_IS_CHAIN(t->target.u.user.name, h));
288 if (strcmp(t->target.u.user.name, STANDARD_TARGET) == 0) {
289 assert(t->target.u.target_size
290 == ALIGN(sizeof(STRUCT_STANDARD_TARGET)));
292 assert(t->verdict == -NF_DROP-1
293 || t->verdict == -NF_ACCEPT-1
294 || t->verdict == RETURN
295 || t->verdict < (int)h->entries.size);
297 if (t->verdict >= 0) {
298 STRUCT_ENTRY *te = get_entry(h, t->verdict);
301 idx = entry2index(h, te);
302 assert(strcmp(GET_TARGET(te)->u.user.name,
307 /* Prior node must be error node, or this node. */
308 assert(t->verdict == entry2offset(h, e)+e->next_offset
309 || strcmp(GET_TARGET(index2entry(h, idx-1))
310 ->u.user.name, IPT_ERROR_TARGET)
314 if (t->verdict == RETURN
315 && unconditional(&e->ip)
316 && e->target_offset == sizeof(*e))
320 } else if (strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0) {
321 assert(t->target.u.target_size
322 == ALIGN(sizeof(struct ipt_error_target)));
324 /* If this is in user area, previous must have been return */
325 if (*off > user_offset)
330 else *was_return = 0;
332 if (*off == user_offset)
333 assert(strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0);
335 (*off) += e->next_offset;
341 /* Do every conceivable sanity check on the handle */
343 do_check(TC_HANDLE_T h, unsigned int line)
346 unsigned int user_offset; /* Offset of first user chain */
349 assert(h->changed == 0 || h->changed == 1);
350 if (strcmp(h->info.name, "filter") == 0) {
351 assert(h->info.valid_hooks
352 == (1 << NF_IP_LOCAL_IN
354 | 1 << NF_IP_LOCAL_OUT));
356 /* Hooks should be first three */
357 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == 0);
359 n = get_chain_end(h, 0);
360 n += get_entry(h, n)->next_offset;
361 assert(h->info.hook_entry[NF_IP_FORWARD] == n);
363 n = get_chain_end(h, n);
364 n += get_entry(h, n)->next_offset;
365 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
367 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
368 } else if (strcmp(h->info.name, "nat") == 0) {
369 assert((h->info.valid_hooks
370 == (1 << NF_IP_PRE_ROUTING
371 | 1 << NF_IP_POST_ROUTING
372 | 1 << NF_IP_LOCAL_OUT)) ||
374 == (1 << NF_IP_PRE_ROUTING
375 | 1 << NF_IP_LOCAL_IN
376 | 1 << NF_IP_POST_ROUTING
377 | 1 << NF_IP_LOCAL_OUT)));
379 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
381 n = get_chain_end(h, 0);
383 n += get_entry(h, n)->next_offset;
384 assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
385 n = get_chain_end(h, n);
387 n += get_entry(h, n)->next_offset;
388 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
389 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
391 if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
392 n = get_chain_end(h, n);
393 n += get_entry(h, n)->next_offset;
394 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
395 user_offset = h->info.hook_entry[NF_IP_LOCAL_IN];
398 } else if (strcmp(h->info.name, "mangle") == 0) {
399 /* This code is getting ugly because linux < 2.4.18-pre6 had
400 * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
402 assert((h->info.valid_hooks
403 == (1 << NF_IP_PRE_ROUTING
404 | 1 << NF_IP_LOCAL_OUT)) ||
406 == (1 << NF_IP_PRE_ROUTING
407 | 1 << NF_IP_LOCAL_IN
409 | 1 << NF_IP_LOCAL_OUT
410 | 1 << NF_IP_POST_ROUTING)));
412 /* Hooks should be first five */
413 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
415 n = get_chain_end(h, 0);
417 if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
418 n += get_entry(h, n)->next_offset;
419 assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
420 n = get_chain_end(h, n);
423 if (h->info.valid_hooks & (1 << NF_IP_FORWARD)) {
424 n += get_entry(h, n)->next_offset;
425 assert(h->info.hook_entry[NF_IP_FORWARD] == n);
426 n = get_chain_end(h, n);
429 n += get_entry(h, n)->next_offset;
430 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
431 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
433 if (h->info.valid_hooks & (1 << NF_IP_POST_ROUTING)) {
434 n = get_chain_end(h, n);
435 n += get_entry(h, n)->next_offset;
436 assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
437 user_offset = h->info.hook_entry[NF_IP_POST_ROUTING];
439 } else if (strcmp(h->info.name, "raw") == 0) {
440 assert(h->info.valid_hooks
441 == (1 << NF_IP_PRE_ROUTING
442 | 1 << NF_IP_LOCAL_OUT));
444 /* Hooks should be first three */
445 assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
447 n = get_chain_end(h, n);
448 n += get_entry(h, n)->next_offset;
449 assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
451 user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
453 #ifdef NF_IP_DROPPING
454 } else if (strcmp(h->info.name, "drop") == 0) {
455 assert(h->info.valid_hooks == (1 << NF_IP_DROPPING));
457 /* Hook should be first */
458 assert(h->info.hook_entry[NF_IP_DROPPING] == 0);
462 fprintf(stderr, "Unknown table `%s'\n", h->info.name);
466 /* User chain == end of last builtin + policy entry */
467 user_offset = get_chain_end(h, user_offset);
468 user_offset += get_entry(h, user_offset)->next_offset;
470 /* Overflows should be end of entry chains, and unconditional
472 for (i = 0; i < NUMHOOKS; i++) {
474 STRUCT_STANDARD_TARGET *t;
476 if (!(h->info.valid_hooks & (1 << i)))
478 assert(h->info.underflow[i]
479 == get_chain_end(h, h->info.hook_entry[i]));
481 e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
482 assert(unconditional(&e->ip));
483 assert(e->target_offset == sizeof(*e));
484 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
485 assert(t->target.u.target_size == ALIGN(sizeof(*t)));
486 assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
488 assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
489 assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
491 /* Hooks and underflows must be valid entries */
492 entry2index(h, get_entry(h, h->info.hook_entry[i]));
493 entry2index(h, get_entry(h, h->info.underflow[i]));
497 >= h->info.num_entries * (sizeof(STRUCT_ENTRY)
498 +sizeof(STRUCT_STANDARD_TARGET)));
500 assert(h->entries.size
502 * (sizeof(STRUCT_ENTRY)
503 + sizeof(STRUCT_STANDARD_TARGET))));
504 assert(strcmp(h->info.name, h->entries.name) == 0);
508 /* Check all the entries. */
509 ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
510 check_entry, &i, &n, user_offset, &was_return, h);
512 assert(i == h->new_number);
513 assert(n == h->entries.size);
515 /* Final entry must be error node */
516 assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
520 #endif /*IPTC_DEBUG*/