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5dea21f7c9cff72a4e8b0e8c0bae837305cb39cb
[project/firewall3.git] / redirects.c
1 /*
2 * firewall3 - 3rd OpenWrt UCI firewall implementation
3 *
4 * Copyright (C) 2013-2014 Jo-Philipp Wich <jow@openwrt.org>
5 *
6 * Permission to use, copy, modify, and/or distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include "redirects.h"
20
21
22 const struct fw3_option fw3_redirect_opts[] = {
23 FW3_OPT("enabled", bool, redirect, enabled),
24
25 FW3_OPT("name", string, redirect, name),
26 FW3_OPT("family", family, redirect, family),
27
28 FW3_OPT("src", device, redirect, src),
29 FW3_OPT("dest", device, redirect, dest),
30
31 FW3_OPT("ipset", setmatch, redirect, ipset),
32
33 FW3_LIST("proto", protocol, redirect, proto),
34
35 FW3_OPT("src_ip", network, redirect, ip_src),
36 FW3_LIST("src_mac", mac, redirect, mac_src),
37 FW3_OPT("src_port", port, redirect, port_src),
38
39 FW3_OPT("src_dip", network, redirect, ip_dest),
40 FW3_OPT("src_dport", port, redirect, port_dest),
41
42 FW3_OPT("dest_ip", network, redirect, ip_redir),
43 FW3_OPT("dest_port", port, redirect, port_redir),
44
45 FW3_OPT("extra", string, redirect, extra),
46
47 FW3_OPT("limit", limit, redirect, limit),
48 FW3_OPT("limit_burst", int, redirect, limit.burst),
49
50 FW3_OPT("utc_time", bool, redirect, time.utc),
51 FW3_OPT("start_date", date, redirect, time.datestart),
52 FW3_OPT("stop_date", date, redirect, time.datestop),
53 FW3_OPT("start_time", time, redirect, time.timestart),
54 FW3_OPT("stop_time", time, redirect, time.timestop),
55 FW3_OPT("weekdays", weekdays, redirect, time.weekdays),
56 FW3_OPT("monthdays", monthdays, redirect, time.monthdays),
57
58 FW3_OPT("mark", mark, redirect, mark),
59
60 FW3_OPT("reflection", bool, redirect, reflection),
61 FW3_OPT("reflection_src", reflection_source,
62 redirect, reflection_src),
63
64 FW3_OPT("target", target, redirect, target),
65
66 { }
67 };
68
69
70 static bool
71 check_families(struct uci_element *e, struct fw3_redirect *r)
72 {
73 if (r->family == FW3_FAMILY_ANY)
74 return true;
75
76 if (r->_src && r->_src->family && r->_src->family != r->family)
77 {
78 warn_elem(e, "refers to source zone with different family");
79 return false;
80 }
81
82 if (r->_dest && r->_dest->family && r->_dest->family != r->family)
83 {
84 warn_elem(e, "refers to destination zone with different family");
85 return false;
86 }
87
88 if (r->ipset.ptr && r->ipset.ptr->family &&
89 r->ipset.ptr->family != r->family)
90 {
91 warn_elem(e, "refers to ipset with different family");
92 return false;
93 }
94
95 if (r->ip_src.family && r->ip_src.family != r->family)
96 {
97 warn_elem(e, "uses source ip with different family");
98 return false;
99 }
100
101 if (r->ip_dest.family && r->ip_dest.family != r->family)
102 {
103 warn_elem(e, "uses destination ip with different family");
104 return false;
105 }
106
107 if (r->ip_redir.family && r->ip_redir.family != r->family)
108 {
109 warn_elem(e, "uses redirect ip with different family");
110 return false;
111 }
112
113 return true;
114 }
115
116 static bool
117 compare_addr(struct fw3_address *a, struct fw3_address *b)
118 {
119 if (a->family != FW3_FAMILY_V4 || b->family != FW3_FAMILY_V4)
120 return false;
121
122 return ((a->address.v4.s_addr & a->mask.v4.s_addr) ==
123 (b->address.v4.s_addr & a->mask.v4.s_addr));
124 }
125
126 static bool
127 resolve_dest(struct uci_element *e, struct fw3_redirect *redir,
128 struct fw3_state *state)
129 {
130 struct fw3_zone *zone;
131 struct fw3_address *addr;
132 struct list_head *addrs;
133
134 if (!redir->ip_redir.set)
135 return false;
136
137 list_for_each_entry(zone, &state->zones, list)
138 {
139 addrs = fw3_resolve_zone_addresses(zone);
140
141 if (!addrs)
142 continue;
143
144 list_for_each_entry(addr, addrs, list)
145 {
146 if (!compare_addr(addr, &redir->ip_redir))
147 continue;
148
149 strncpy(redir->dest.name, zone->name, sizeof(redir->dest.name));
150 redir->dest.set = true;
151 redir->_dest = zone;
152
153 break;
154 }
155
156 fw3_free_list(addrs);
157
158 if (redir->_dest)
159 return true;
160 }
161
162 return false;
163 }
164
165 static bool
166 check_local(struct uci_element *e, struct fw3_redirect *redir,
167 struct fw3_state *state)
168 {
169 struct fw3_zone *zone;
170 struct fw3_device *net;
171 struct fw3_address *addr, *tmp;
172
173 if (redir->target != FW3_FLAG_DNAT)
174 return false;
175
176 if (!redir->ip_redir.set)
177 redir->local = true;
178
179 if (redir->local)
180 return true;
181
182 list_for_each_entry(zone, &state->zones, list)
183 {
184 list_for_each_entry(net, &zone->networks, list)
185 {
186 LIST_HEAD(addrs);
187
188 fw3_ubus_address(&addrs, net->name);
189 list_for_each_entry_safe(addr, tmp, &addrs, list)
190 {
191 if (compare_addr(&redir->ip_redir, addr)) {
192 warn_elem(e, "refers to a destination address on this router, "
193 "assuming port redirection");
194
195 redir->local = true;
196 continue;
197 }
198
199 list_del(&addr->list);
200 free(addr);
201 }
202
203 if (redir->local)
204 return true;
205 }
206 }
207
208 return false;
209 }
210
211 void
212 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
213 {
214 struct uci_section *s;
215 struct uci_element *e;
216 struct fw3_redirect *redir;
217
218 bool valid;
219
220 INIT_LIST_HEAD(&state->redirects);
221
222 uci_foreach_element(&p->sections, e)
223 {
224 s = uci_to_section(e);
225
226 if (strcmp(s->type, "redirect"))
227 continue;
228
229 redir = calloc(1, sizeof(*redir));
230 if (!redir)
231 continue;
232
233 INIT_LIST_HEAD(&redir->proto);
234 INIT_LIST_HEAD(&redir->mac_src);
235
236 redir->enabled = true;
237 redir->reflection = true;
238
239 valid = false;
240
241 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
242 {
243 warn_elem(e, "skipped due to invalid options");
244 fw3_free_redirect(redir);
245 continue;
246 }
247
248 if (!redir->enabled)
249 {
250 fw3_free_redirect(redir);
251 continue;
252 }
253
254 if (redir->src.invert)
255 {
256 warn_elem(e, "must not have an inverted source");
257 fw3_free_redirect(redir);
258 continue;
259 }
260 else if (redir->src.set && !redir->src.any &&
261 !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
262 {
263 warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
264 fw3_free_redirect(redir);
265 continue;
266 }
267 else if (redir->dest.set && !redir->dest.any &&
268 !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
269 {
270 warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
271 fw3_free_redirect(redir);
272 continue;
273 }
274 else if (redir->ipset.set && state->disable_ipsets)
275 {
276 warn_elem(e, "skipped due to disabled ipset support");
277 fw3_free_redirect(redir);
278 continue;
279 }
280 else if (redir->ipset.set &&
281 !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
282 {
283 warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
284 fw3_free_redirect(redir);
285 continue;
286 }
287
288 if (!check_families(e, redir))
289 {
290 fw3_free_redirect(redir);
291 continue;
292 }
293
294 if (redir->target == FW3_FLAG_UNSPEC)
295 {
296 warn_elem(e, "has no target specified, defaulting to DNAT");
297 redir->target = FW3_FLAG_DNAT;
298 }
299 else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
300 {
301 warn_elem(e, "has invalid target specified, defaulting to DNAT");
302 redir->target = FW3_FLAG_DNAT;
303 }
304
305 if (redir->target == FW3_FLAG_DNAT)
306 {
307 if (redir->src.any)
308 warn_elem(e, "must not have source '*' for DNAT target");
309 else if (!redir->_src)
310 warn_elem(e, "has no source specified");
311 else
312 {
313 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
314 redir->_src->conntrack = true;
315 valid = true;
316 }
317
318 if (!check_local(e, redir, state) && !redir->dest.set &&
319 resolve_dest(e, redir, state))
320 {
321 warn_elem(e, "does not specify a destination, assuming '%s'",
322 redir->dest.name);
323 }
324
325 if (redir->reflection && redir->_dest && redir->_src->masq)
326 {
327 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
328 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
329 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
330 }
331 }
332 else
333 {
334 if (redir->dest.any)
335 warn_elem(e, "must not have destination '*' for SNAT target");
336 else if (!redir->_dest)
337 warn_elem(e, "has no destination specified");
338 else if (!redir->ip_dest.set)
339 warn_elem(e, "has no src_dip option specified");
340 else if (!list_empty(&redir->mac_src))
341 warn_elem(e, "must not use 'src_mac' option for SNAT target");
342 else
343 {
344 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
345 redir->_dest->conntrack = true;
346 valid = true;
347 }
348 }
349
350 if (list_empty(&redir->proto))
351 {
352 warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
353 fw3_parse_protocol(&redir->proto, "tcpudp", true);
354 }
355
356 if (!valid)
357 {
358 fw3_free_redirect(redir);
359 continue;
360 }
361
362 if (!redir->port_redir.set)
363 redir->port_redir = redir->port_dest;
364
365 list_add_tail(&redir->list, &state->redirects);
366 }
367 }
368
369 static void
370 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
371 {
372 if (redir->target == FW3_FLAG_DNAT)
373 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
374 else
375 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
376 }
377
378 static void
379 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
380 struct fw3_address *addr, struct fw3_port *port)
381 {
382 char buf[sizeof("255.255.255.255:65535-65535\0")];
383
384 buf[0] = '\0';
385
386 if (addr && addr->set)
387 {
388 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
389 }
390
391 if (port && port->set)
392 {
393 if (port->port_min == port->port_max)
394 sprintf(buf + strlen(buf), ":%u", port->port_min);
395 else
396 sprintf(buf + strlen(buf), ":%u-%u",
397 port->port_min, port->port_max);
398 }
399
400 if (target == FW3_FLAG_DNAT)
401 {
402 fw3_ipt_rule_target(r, "DNAT");
403 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
404 }
405 else
406 {
407 fw3_ipt_rule_target(r, "SNAT");
408 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
409 }
410 }
411
412 static void
413 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
414 {
415 if (redir->target == FW3_FLAG_DNAT)
416 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
417 else
418 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
419 }
420
421 static void
422 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
423 {
424 if (name)
425 {
426 if (ref)
427 fw3_ipt_rule_comment(r, "%s (reflection)", name);
428 else
429 fw3_ipt_rule_comment(r, name);
430 }
431 else
432 {
433 if (ref)
434 fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
435 else
436 fw3_ipt_rule_comment(r, "@redirect[%u]", num);
437 }
438 }
439
440 static void
441 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
442 struct fw3_redirect *redir, int num,
443 struct fw3_protocol *proto, struct fw3_mac *mac)
444 {
445 struct fw3_ipt_rule *r;
446 struct fw3_address *src, *dst;
447 struct fw3_port *spt, *dpt;
448
449 switch (h->table)
450 {
451 case FW3_TABLE_NAT:
452 src = &redir->ip_src;
453 dst = &redir->ip_dest;
454 spt = &redir->port_src;
455 dpt = &redir->port_dest;
456
457 if (redir->target == FW3_FLAG_SNAT)
458 {
459 dst = &redir->ip_redir;
460 dpt = &redir->port_redir;
461 }
462
463 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
464 fw3_ipt_rule_sport_dport(r, spt, dpt);
465 fw3_ipt_rule_mac(r, mac);
466 fw3_ipt_rule_ipset(r, &redir->ipset);
467 fw3_ipt_rule_limit(r, &redir->limit);
468 fw3_ipt_rule_time(r, &redir->time);
469 fw3_ipt_rule_mark(r, &redir->mark);
470 set_target_nat(r, redir);
471 fw3_ipt_rule_extra(r, redir->extra);
472 set_comment(r, redir->name, num, false);
473 append_chain_nat(r, redir);
474 break;
475
476 default:
477 break;
478 }
479 }
480
481 static void
482 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
483 struct fw3_redirect *redir, int num,
484 struct fw3_protocol *proto, struct fw3_address *ra,
485 struct fw3_address *ia, struct fw3_address *ea)
486 {
487 struct fw3_ipt_rule *r;
488
489 switch (h->table)
490 {
491 case FW3_TABLE_NAT:
492 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
493 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
494 fw3_ipt_rule_limit(r, &redir->limit);
495 fw3_ipt_rule_time(r, &redir->time);
496 set_comment(r, redir->name, num, true);
497 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
498 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
499
500 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
501 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
502 fw3_ipt_rule_limit(r, &redir->limit);
503 fw3_ipt_rule_time(r, &redir->time);
504 set_comment(r, redir->name, num, true);
505 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
506 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
507 break;
508
509 default:
510 break;
511 }
512 }
513
514 static void
515 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
516 struct fw3_redirect *redir, int num)
517 {
518 struct list_head *ext_addrs, *int_addrs;
519 struct fw3_address *ext_addr, *int_addr, ref_addr;
520 struct fw3_protocol *proto;
521 struct fw3_mac *mac;
522
523 if (redir->name)
524 info(" * Redirect '%s'", redir->name);
525 else
526 info(" * Redirect #%u", num);
527
528 if (!fw3_is_family(redir->_src, handle->family) ||
529 !fw3_is_family(redir->_dest, handle->family))
530 {
531 info(" ! Skipping due to different family of zone");
532 return;
533 }
534
535 if (!fw3_is_family(&redir->ip_src, handle->family) ||
536 !fw3_is_family(&redir->ip_dest, handle->family) ||
537 !fw3_is_family(&redir->ip_redir, handle->family))
538 {
539 if (!redir->ip_src.resolved ||
540 !redir->ip_dest.resolved ||
541 !redir->ip_redir.resolved)
542 info(" ! Skipping due to different family of ip address");
543
544 return;
545 }
546
547 if (redir->ipset.ptr)
548 {
549 if (!fw3_is_family(redir->ipset.ptr, handle->family))
550 {
551 info(" ! Skipping due to different family in ipset");
552 return;
553 }
554
555 if (!fw3_check_ipset(redir->ipset.ptr))
556 {
557 info(" ! Skipping due to missing ipset '%s'",
558 redir->ipset.ptr->external ?
559 redir->ipset.ptr->external : redir->ipset.ptr->name);
560 return;
561 }
562
563 set(redir->ipset.ptr->flags, handle->family, handle->family);
564 }
565
566 fw3_foreach(proto, &redir->proto)
567 fw3_foreach(mac, &redir->mac_src)
568 print_redirect(handle, state, redir, num, proto, mac);
569
570 /* reflection rules */
571 if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
572 return;
573
574 if (!redir->_dest || !redir->_src->masq)
575 return;
576
577 ext_addrs = fw3_resolve_zone_addresses(redir->_src);
578 int_addrs = fw3_resolve_zone_addresses(redir->_dest);
579
580 if (!ext_addrs || !int_addrs)
581 goto out;
582
583 list_for_each_entry(ext_addr, ext_addrs, list)
584 {
585 if (!fw3_is_family(ext_addr, handle->family))
586 continue;
587
588 list_for_each_entry(int_addr, int_addrs, list)
589 {
590 if (!fw3_is_family(int_addr, handle->family))
591 continue;
592
593 fw3_foreach(proto, &redir->proto)
594 {
595 if (!proto)
596 continue;
597
598 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
599 ref_addr = *int_addr;
600 else
601 ref_addr = *ext_addr;
602
603 ref_addr.mask.v4.s_addr = 0xFFFFFFFF;
604 ext_addr->mask.v4.s_addr = 0xFFFFFFFF;
605
606 print_reflection(handle, state, redir, num, proto,
607 &ref_addr, int_addr, ext_addr);
608 }
609 }
610 }
611
612 out:
613 fw3_free_list(ext_addrs);
614 fw3_free_list(int_addrs);
615 }
616
617 void
618 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
619 {
620 int num = 0;
621 struct fw3_redirect *redir;
622
623 if (handle->family == FW3_FAMILY_V6)
624 return;
625
626 if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
627 return;
628
629 list_for_each_entry(redir, &state->redirects, list)
630 expand_redirect(handle, state, redir, num++);
631 }
OpenWrt firewall configuration utility