18666a3c7dfd5940bbf66a94b1bd8accbb2d818e
[project/firewall3.git] / redirects.c
1 /*
2  * firewall3 - 3rd OpenWrt UCI firewall implementation
3  *
4  *   Copyright (C) 2013 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         uint32_t mask;
120
121         if (a->family != FW3_FAMILY_V4 || b->family != FW3_FAMILY_V4)
122                 return false;
123
124         mask = htonl(~((1 << (32 - a->mask)) - 1));
125
126         return ((a->address.v4.s_addr & mask) == (b->address.v4.s_addr & mask));
127 }
128
129 static bool
130 resolve_dest(struct uci_element *e, struct fw3_redirect *redir,
131              struct fw3_state *state)
132 {
133         struct fw3_zone *zone;
134         struct fw3_address *addr;
135         struct list_head *addrs;
136
137         if (!redir->ip_redir.set)
138                 return false;
139
140         list_for_each_entry(zone, &state->zones, list)
141         {
142                 addrs = fw3_resolve_zone_addresses(zone);
143
144                 if (!addrs)
145                         continue;
146
147                 list_for_each_entry(addr, addrs, list)
148                 {
149                         if (!compare_addr(addr, &redir->ip_redir))
150                                 continue;
151
152                         strncpy(redir->dest.name, zone->name, sizeof(redir->dest.name));
153                         redir->dest.set = true;
154                         redir->_dest = zone;
155
156                         break;
157                 }
158
159                 fw3_free_list(addrs);
160
161                 if (redir->_dest)
162                         return true;
163         }
164
165         return false;
166 }
167
168 static bool
169 check_local(struct uci_element *e, struct fw3_redirect *redir,
170             struct fw3_state *state)
171 {
172         struct fw3_zone *zone;
173         struct fw3_device *net;
174         struct fw3_address *addr;
175         struct list_head *addrs;
176
177         if (redir->target != FW3_FLAG_DNAT)
178                 return false;
179
180         if (!redir->ip_redir.set)
181                 redir->local = true;
182
183         if (redir->local)
184                 return true;
185
186         list_for_each_entry(zone, &state->zones, list)
187         {
188                 list_for_each_entry(net, &zone->networks, list)
189                 {
190                         addrs = fw3_ubus_address(net->name);
191
192                         if (!addrs)
193                                 continue;
194
195                         list_for_each_entry(addr, addrs, list)
196                         {
197                                 if (!compare_addr(&redir->ip_redir, addr))
198                                         continue;
199
200                                 warn_elem(e, "refers to a destination address on this router, "
201                                              "assuming port redirection");
202
203                                 redir->local = true;
204                                 break;
205                         }
206
207                         fw3_free_list(addrs);
208
209                         if (redir->local)
210                                 return true;
211                 }
212         }
213
214         return false;
215 }
216
217 void
218 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
219 {
220         struct uci_section *s;
221         struct uci_element *e;
222         struct fw3_redirect *redir;
223
224         bool valid;
225
226         INIT_LIST_HEAD(&state->redirects);
227
228         uci_foreach_element(&p->sections, e)
229         {
230                 s = uci_to_section(e);
231
232                 if (strcmp(s->type, "redirect"))
233                         continue;
234
235                 redir = malloc(sizeof(*redir));
236
237                 if (!redir)
238                         continue;
239
240                 memset(redir, 0, sizeof(*redir));
241
242                 INIT_LIST_HEAD(&redir->proto);
243                 INIT_LIST_HEAD(&redir->mac_src);
244
245                 redir->enabled = true;
246                 redir->reflection = true;
247
248                 valid = false;
249
250                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
251                 {
252                         warn_elem(e, "skipped due to invalid options");
253                         fw3_free_redirect(redir);
254                         continue;
255                 }
256
257                 if (!redir->enabled)
258                 {
259                         fw3_free_redirect(redir);
260                         continue;
261                 }
262
263                 if (redir->src.invert)
264                 {
265                         warn_elem(e, "must not have an inverted source");
266                         fw3_free_redirect(redir);
267                         continue;
268                 }
269                 else if (redir->src.set && !redir->src.any &&
270                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
271                 {
272                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
273                         fw3_free_redirect(redir);
274                         continue;
275                 }
276                 else if (redir->dest.set && !redir->dest.any &&
277                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
278                 {
279                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
280                         fw3_free_redirect(redir);
281                         continue;
282                 }
283                 else if (redir->ipset.set && state->disable_ipsets)
284                 {
285                         warn_elem(e, "skipped due to disabled ipset support");
286                         fw3_free_redirect(redir);
287                         continue;
288                 }
289                 else if (redir->ipset.set &&
290                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
291                 {
292                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
293                         fw3_free_redirect(redir);
294                         continue;
295                 }
296
297                 if (!check_families(e, redir))
298                 {
299                         fw3_free_redirect(redir);
300                         continue;
301                 }
302
303                 if (redir->target == FW3_FLAG_UNSPEC)
304                 {
305                         warn_elem(e, "has no target specified, defaulting to DNAT");
306                         redir->target = FW3_FLAG_DNAT;
307                 }
308                 else if (redir->target < FW3_FLAG_DNAT)
309                 {
310                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
311                         redir->target = FW3_FLAG_DNAT;
312                 }
313
314                 if (redir->target == FW3_FLAG_DNAT)
315                 {
316                         if (redir->src.any)
317                                 warn_elem(e, "must not have source '*' for DNAT target");
318                         else if (!redir->_src)
319                                 warn_elem(e, "has no source specified");
320                         else
321                         {
322                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
323                                 redir->_src->conntrack = true;
324                                 valid = true;
325                         }
326
327                         if (!check_local(e, redir, state) && !redir->dest.set &&
328                             resolve_dest(e, redir, state))
329                         {
330                                 warn_elem(e, "does not specify a destination, assuming '%s'",
331                                           redir->dest.name);
332                         }
333
334                         if (redir->reflection && redir->_dest && redir->_src->masq)
335                         {
336                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
337                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
338                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
339                         }
340                 }
341                 else
342                 {
343                         if (redir->dest.any)
344                                 warn_elem(e, "must not have destination '*' for SNAT target");
345                         else if (!redir->_dest)
346                                 warn_elem(e, "has no destination specified");
347                         else if (!redir->ip_dest.set)
348                                 warn_elem(e, "has no src_dip option specified");
349                         else if (!list_empty(&redir->mac_src))
350                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
351                         else
352                         {
353                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
354                                 redir->_dest->conntrack = true;
355                                 valid = true;
356                         }
357                 }
358
359                 if (list_empty(&redir->proto))
360                 {
361                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
362                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
363                 }
364
365                 if (!valid)
366                 {
367                         fw3_free_redirect(redir);
368                         continue;
369                 }
370
371                 if (!redir->port_redir.set)
372                         redir->port_redir = redir->port_dest;
373
374                 list_add_tail(&redir->list, &state->redirects);
375         }
376 }
377
378 static void
379 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
380 {
381         if (redir->target == FW3_FLAG_DNAT)
382                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
383         else
384                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
385 }
386
387 static void
388 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
389               struct fw3_address *addr, struct fw3_port *port)
390 {
391         char buf[sizeof("255.255.255.255:65535-65535\0")];
392
393         buf[0] = '\0';
394
395         if (addr && addr->set)
396         {
397                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
398         }
399
400         if (port && port->set)
401         {
402                 if (port->port_min == port->port_max)
403                         sprintf(buf + strlen(buf), ":%u", port->port_min);
404                 else
405                         sprintf(buf + strlen(buf), ":%u-%u",
406                                 port->port_min, port->port_max);
407         }
408
409         if (target == FW3_FLAG_DNAT)
410         {
411                 fw3_ipt_rule_target(r, "DNAT");
412                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
413         }
414         else
415         {
416                 fw3_ipt_rule_target(r, "SNAT");
417                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
418         }
419 }
420
421 static void
422 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
423 {
424         if (redir->target == FW3_FLAG_DNAT)
425                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
426         else
427                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
428 }
429
430 static void
431 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
432 {
433         if (name)
434         {
435                 if (ref)
436                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
437                 else
438                         fw3_ipt_rule_comment(r, name);
439         }
440         else
441         {
442                 if (ref)
443                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
444                 else
445                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
446         }
447 }
448
449 static void
450 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
451                struct fw3_redirect *redir, int num,
452                struct fw3_protocol *proto, struct fw3_mac *mac)
453 {
454         struct fw3_ipt_rule *r;
455         struct fw3_address *src, *dst;
456         struct fw3_port *spt, *dpt;
457
458         switch (h->table)
459         {
460         case FW3_TABLE_NAT:
461                 src = &redir->ip_src;
462                 dst = &redir->ip_dest;
463                 spt = &redir->port_src;
464                 dpt = &redir->port_dest;
465
466                 if (redir->target == FW3_FLAG_SNAT)
467                 {
468                         dst = &redir->ip_redir;
469                         dpt = &redir->port_redir;
470                 }
471
472                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
473                 fw3_ipt_rule_sport_dport(r, spt, dpt);
474                 fw3_ipt_rule_mac(r, mac);
475                 fw3_ipt_rule_ipset(r, &redir->ipset);
476                 fw3_ipt_rule_limit(r, &redir->limit);
477                 fw3_ipt_rule_time(r, &redir->time);
478                 fw3_ipt_rule_mark(r, &redir->mark);
479                 set_target_nat(r, redir);
480                 fw3_ipt_rule_extra(r, redir->extra);
481                 set_comment(r, redir->name, num, false);
482                 append_chain_nat(r, redir);
483                 break;
484
485         default:
486                 break;
487         }
488 }
489
490 static void
491 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
492                  struct fw3_redirect *redir, int num,
493                  struct fw3_protocol *proto, struct fw3_address *ra,
494                  struct fw3_address *ia, struct fw3_address *ea)
495 {
496         struct fw3_ipt_rule *r;
497
498         switch (h->table)
499         {
500         case FW3_TABLE_NAT:
501                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
502                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
503                 fw3_ipt_rule_limit(r, &redir->limit);
504                 fw3_ipt_rule_time(r, &redir->time);
505                 set_comment(r, redir->name, num, true);
506                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
507                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
508
509                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
510                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
511                 fw3_ipt_rule_limit(r, &redir->limit);
512                 fw3_ipt_rule_time(r, &redir->time);
513                 set_comment(r, redir->name, num, true);
514                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
515                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
516                 break;
517
518         default:
519                 break;
520         }
521 }
522
523 static void
524 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
525                 struct fw3_redirect *redir, int num)
526 {
527         struct list_head *ext_addrs, *int_addrs;
528         struct fw3_address *ext_addr, *int_addr, ref_addr;
529         struct fw3_protocol *proto;
530         struct fw3_mac *mac;
531
532         if (redir->name)
533                 info("   * Redirect '%s'", redir->name);
534         else
535                 info("   * Redirect #%u", num);
536
537         if (!fw3_is_family(redir->_src, handle->family) ||
538                 !fw3_is_family(redir->_dest, handle->family))
539         {
540                 info("     ! Skipping due to different family of zone");
541                 return;
542         }
543
544         if (!fw3_is_family(&redir->ip_src, handle->family) ||
545             !fw3_is_family(&redir->ip_dest, handle->family) ||
546                 !fw3_is_family(&redir->ip_redir, handle->family))
547         {
548                 if (!redir->ip_src.resolved ||
549                     !redir->ip_dest.resolved ||
550                     !redir->ip_redir.resolved)
551                         info("     ! Skipping due to different family of ip address");
552
553                 return;
554         }
555
556         if (redir->ipset.ptr)
557         {
558                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
559                 {
560                         info("     ! Skipping due to different family in ipset");
561                         return;
562                 }
563
564                 if (!fw3_check_ipset(redir->ipset.ptr))
565                 {
566                         info("     ! Skipping due to missing ipset '%s'",
567                              redir->ipset.ptr->external ?
568                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
569                         return;
570                 }
571
572                 set(redir->ipset.ptr->flags, handle->family, handle->family);
573         }
574
575         fw3_foreach(proto, &redir->proto)
576         fw3_foreach(mac, &redir->mac_src)
577                 print_redirect(handle, state, redir, num, proto, mac);
578
579         /* reflection rules */
580         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
581                 return;
582
583         if (!redir->_dest || !redir->_src->masq)
584                 return;
585
586         ext_addrs = fw3_resolve_zone_addresses(redir->_src);
587         int_addrs = fw3_resolve_zone_addresses(redir->_dest);
588
589         if (!ext_addrs || !int_addrs)
590                 goto out;
591
592         list_for_each_entry(ext_addr, ext_addrs, list)
593         {
594                 if (!fw3_is_family(ext_addr, handle->family))
595                         continue;
596
597                 list_for_each_entry(int_addr, int_addrs, list)
598                 {
599                         if (!fw3_is_family(int_addr, handle->family))
600                                 continue;
601
602                         fw3_foreach(proto, &redir->proto)
603                         {
604                                 if (!proto)
605                                         continue;
606
607                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
608                                         ref_addr = *int_addr;
609                                 else
610                                         ref_addr = *ext_addr;
611
612                                 ref_addr.mask = 32;
613                                 ext_addr->mask = 32;
614
615                                 print_reflection(handle, state, redir, num, proto,
616                                                                  &ref_addr, int_addr, ext_addr);
617                         }
618                 }
619         }
620
621 out:
622         fw3_free_list(ext_addrs);
623         fw3_free_list(int_addrs);
624 }
625
626 void
627 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
628 {
629         int num = 0;
630         struct fw3_redirect *redir;
631
632         if (handle->family == FW3_FAMILY_V6)
633                 return;
634
635         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
636                 return;
637
638         list_for_each_entry(redir, &state->redirects, list)
639                 expand_redirect(handle, state, redir, num++);
640 }