1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/ipv6/fib6_rules.c IPv6 Routing Policy Rules
4 *
5 * Copyright (C)2003-2006 Helsinki University of Technology
6 * Copyright (C)2003-2006 USAGI/WIDE Project
7 *
8 * Authors
9 * Thomas Graf <tgraf@suug.ch>
10 * Ville Nuorvala <vnuorval@tcs.hut.fi>
11 */
12
13 #include <linux/netdevice.h>
14 #include <linux/notifier.h>
15 #include <linux/export.h>
16 #include <linux/indirect_call_wrapper.h>
17
18 #include <net/fib_rules.h>
19 #include <net/inet_dscp.h>
20 #include <net/ipv6.h>
21 #include <net/addrconf.h>
22 #include <net/ip6_route.h>
23 #include <net/netlink.h>
24
25 struct fib6_rule {
26 struct fib_rule common;
27 struct rt6key src;
28 struct rt6key dst;
29 dscp_t dscp;
30 };
31
32 static bool fib6_rule_matchall(const struct fib_rule *rule)
33 {
34 struct fib6_rule *r = container_of(rule, struct fib6_rule, common);
35
36 if (r->dst.plen || r->src.plen || r->dscp)
37 return false;
38 return fib_rule_matchall(rule);
39 }
40
41 bool fib6_rule_default(const struct fib_rule *rule)
42 {
43 if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
44 rule->l3mdev)
45 return false;
46 if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
47 return false;
48 return true;
49 }
50 EXPORT_SYMBOL_GPL(fib6_rule_default);
51
52 int fib6_rules_dump(struct net *net, struct notifier_block *nb,
53 struct netlink_ext_ack *extack)
54 {
55 return fib_rules_dump(net, nb, AF_INET6, extack);
56 }
57
58 unsigned int fib6_rules_seq_read(struct net *net)
59 {
60 return fib_rules_seq_read(net, AF_INET6);
61 }
62
63 /* called with rcu lock held; no reference taken on fib6_info */
64 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
65 struct fib6_result *res, int flags)
66 {
67 int err;
68
69 if (net->ipv6.fib6_has_custom_rules) {
70 struct fib_lookup_arg arg = {
71 .lookup_ptr = fib6_table_lookup,
72 .lookup_data = &oif,
73 .result = res,
74 .flags = FIB_LOOKUP_NOREF,
75 };
76
77 l3mdev_update_flow(net, flowi6_to_flowi(fl6));
78
79 err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
80 flowi6_to_flowi(fl6), flags, &arg);
81 } else {
82 err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
83 fl6, res, flags);
84 if (err || res->f6i == net->ipv6.fib6_null_entry)
85 err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
86 oif, fl6, res, flags);
87 }
88
89 return err;
90 }
91
92 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
93 const struct sk_buff *skb,
94 int flags, pol_lookup_t lookup)
95 {
96 if (net->ipv6.fib6_has_custom_rules) {
97 struct fib6_result res = {};
98 struct fib_lookup_arg arg = {
99 .lookup_ptr = lookup,
100 .lookup_data = skb,
101 .result = &res,
102 .flags = FIB_LOOKUP_NOREF,
103 };
104
105 /* update flow if oif or iif point to device enslaved to l3mdev */
106 l3mdev_update_flow(net, flowi6_to_flowi(fl6));
107
108 fib_rules_lookup(net->ipv6.fib6_rules_ops,
109 flowi6_to_flowi(fl6), flags, &arg);
110
111 if (res.rt6)
112 return &res.rt6->dst;
113 } else {
114 struct rt6_info *rt;
115
116 rt = pol_lookup_func(lookup,
117 net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
118 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
119 return &rt->dst;
120 ip6_rt_put_flags(rt, flags);
121 rt = pol_lookup_func(lookup,
122 net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
123 if (rt->dst.error != -EAGAIN)
124 return &rt->dst;
125 ip6_rt_put_flags(rt, flags);
126 }
127
128 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
129 dst_hold(&net->ipv6.ip6_null_entry->dst);
130 return &net->ipv6.ip6_null_entry->dst;
131 }
132
133 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags,
134 struct flowi6 *flp6, const struct net_device *dev)
135 {
136 struct fib6_rule *r = (struct fib6_rule *)rule;
137
138 /* If we need to find a source address for this traffic,
139 * we check the result if it meets requirement of the rule.
140 */
141 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
142 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
143 struct in6_addr saddr;
144
145 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr,
146 rt6_flags2srcprefs(flags), &saddr))
147 return -EAGAIN;
148
149 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen))
150 return -EAGAIN;
151
152 flp6->saddr = saddr;
153 }
154
155 return 0;
156 }
157
158 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
159 int flags, struct fib_lookup_arg *arg)
160 {
161 struct fib6_result *res = arg->result;
162 struct flowi6 *flp6 = &flp->u.ip6;
163 struct net *net = rule->fr_net;
164 struct fib6_table *table;
165 int err, *oif;
166 u32 tb_id;
167
168 switch (rule->action) {
169 case FR_ACT_TO_TBL:
170 break;
171 case FR_ACT_UNREACHABLE:
172 return -ENETUNREACH;
173 case FR_ACT_PROHIBIT:
174 return -EACCES;
175 case FR_ACT_BLACKHOLE:
176 default:
177 return -EINVAL;
178 }
179
180 tb_id = fib_rule_get_table(rule, arg);
181 table = fib6_get_table(net, tb_id);
182 if (!table)
183 return -EAGAIN;
184
185 oif = (int *)arg->lookup_data;
186 err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
187 if (!err && res->f6i != net->ipv6.fib6_null_entry)
188 err = fib6_rule_saddr(net, rule, flags, flp6,
189 res->nh->fib_nh_dev);
190 else
191 err = -EAGAIN;
192
193 return err;
194 }
195
196 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
197 int flags, struct fib_lookup_arg *arg)
198 {
199 struct fib6_result *res = arg->result;
200 struct flowi6 *flp6 = &flp->u.ip6;
201 struct rt6_info *rt = NULL;
202 struct fib6_table *table;
203 struct net *net = rule->fr_net;
204 pol_lookup_t lookup = arg->lookup_ptr;
205 int err = 0;
206 u32 tb_id;
207
208 switch (rule->action) {
209 case FR_ACT_TO_TBL:
210 break;
211 case FR_ACT_UNREACHABLE:
212 err = -ENETUNREACH;
213 rt = net->ipv6.ip6_null_entry;
214 goto discard_pkt;
215 default:
216 case FR_ACT_BLACKHOLE:
217 err = -EINVAL;
218 rt = net->ipv6.ip6_blk_hole_entry;
219 goto discard_pkt;
220 case FR_ACT_PROHIBIT:
221 err = -EACCES;
222 rt = net->ipv6.ip6_prohibit_entry;
223 goto discard_pkt;
224 }
225
226 tb_id = fib_rule_get_table(rule, arg);
227 table = fib6_get_table(net, tb_id);
228 if (!table) {
229 err = -EAGAIN;
230 goto out;
231 }
232
233 rt = pol_lookup_func(lookup,
234 net, table, flp6, arg->lookup_data, flags);
235 if (rt != net->ipv6.ip6_null_entry) {
236 struct inet6_dev *idev = ip6_dst_idev(&rt->dst);
237
238 if (!idev)
239 goto again;
240 err = fib6_rule_saddr(net, rule, flags, flp6,
241 idev->dev);
242
243 if (err == -EAGAIN)
244 goto again;
245
246 err = rt->dst.error;
247 if (err != -EAGAIN)
248 goto out;
249 }
250 again:
251 ip6_rt_put_flags(rt, flags);
252 err = -EAGAIN;
253 rt = NULL;
254 goto out;
255
256 discard_pkt:
257 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
258 dst_hold(&rt->dst);
259 out:
260 res->rt6 = rt;
261 return err;
262 }
263
264 INDIRECT_CALLABLE_SCOPE int fib6_rule_action(struct fib_rule *rule,
265 struct flowi *flp, int flags,
266 struct fib_lookup_arg *arg)
267 {
268 if (arg->lookup_ptr == fib6_table_lookup)
269 return fib6_rule_action_alt(rule, flp, flags, arg);
270
271 return __fib6_rule_action(rule, flp, flags, arg);
272 }
273
274 INDIRECT_CALLABLE_SCOPE bool fib6_rule_suppress(struct fib_rule *rule,
275 int flags,
276 struct fib_lookup_arg *arg)
277 {
278 struct fib6_result *res = arg->result;
279 struct rt6_info *rt = res->rt6;
280 struct net_device *dev = NULL;
281
282 if (!rt)
283 return false;
284
285 if (rt->rt6i_idev)
286 dev = rt->rt6i_idev->dev;
287
288 /* do not accept result if the route does
289 * not meet the required prefix length
290 */
291 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
292 goto suppress_route;
293
294 /* do not accept result if the route uses a device
295 * belonging to a forbidden interface group
296 */
297 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
298 goto suppress_route;
299
300 return false;
301
302 suppress_route:
303 ip6_rt_put_flags(rt, flags);
304 return true;
305 }
306
307 INDIRECT_CALLABLE_SCOPE int fib6_rule_match(struct fib_rule *rule,
308 struct flowi *fl, int flags)
309 {
310 struct fib6_rule *r = (struct fib6_rule *) rule;
311 struct flowi6 *fl6 = &fl->u.ip6;
312
313 if (r->dst.plen &&
314 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
315 return 0;
316
317 /*
318 * If FIB_RULE_FIND_SADDR is set and we do not have a
319 * source address for the traffic, we defer check for
320 * source address.
321 */
322 if (r->src.plen) {
323 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
324 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
325 r->src.plen))
326 return 0;
327 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
328 return 0;
329 }
330
331 if (r->dscp && r->dscp != ip6_dscp(fl6->flowlabel))
332 return 0;
333
334 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
335 return 0;
336
337 if (fib_rule_port_range_set(&rule->sport_range) &&
338 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
339 return 0;
340
341 if (fib_rule_port_range_set(&rule->dport_range) &&
342 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
343 return 0;
344
345 return 1;
346 }
347
348 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
349 struct fib_rule_hdr *frh,
350 struct nlattr **tb,
351 struct netlink_ext_ack *extack)
352 {
353 int err = -EINVAL;
354 struct net *net = sock_net(skb->sk);
355 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
356
357 if (!inet_validate_dscp(frh->tos)) {
358 NL_SET_ERR_MSG(extack,
359 "Invalid dsfield (tos): ECN bits must be 0");
360 goto errout;
361 }
362 rule6->dscp = inet_dsfield_to_dscp(frh->tos);
363
364 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
365 if (rule->table == RT6_TABLE_UNSPEC) {
366 NL_SET_ERR_MSG(extack, "Invalid table");
367 goto errout;
368 }
369
370 if (fib6_new_table(net, rule->table) == NULL) {
371 err = -ENOBUFS;
372 goto errout;
373 }
374 }
375
376 if (frh->src_len)
377 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);
378
379 if (frh->dst_len)
380 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);
381
382 rule6->src.plen = frh->src_len;
383 rule6->dst.plen = frh->dst_len;
384
385 if (fib_rule_requires_fldissect(rule))
386 net->ipv6.fib6_rules_require_fldissect++;
387
388 net->ipv6.fib6_has_custom_rules = true;
389 err = 0;
390 errout:
391 return err;
392 }
393
394 static int fib6_rule_delete(struct fib_rule *rule)
395 {
396 struct net *net = rule->fr_net;
397
398 if (net->ipv6.fib6_rules_require_fldissect &&
399 fib_rule_requires_fldissect(rule))
400 net->ipv6.fib6_rules_require_fldissect--;
401
402 return 0;
403 }
404
405 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
406 struct nlattr **tb)
407 {
408 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
409
410 if (frh->src_len && (rule6->src.plen != frh->src_len))
411 return 0;
412
413 if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
414 return 0;
415
416 if (frh->tos && inet_dscp_to_dsfield(rule6->dscp) != frh->tos)
417 return 0;
418
419 if (frh->src_len &&
420 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
421 return 0;
422
423 if (frh->dst_len &&
424 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
425 return 0;
426
427 return 1;
428 }
429
430 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
431 struct fib_rule_hdr *frh)
432 {
433 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
434
435 frh->dst_len = rule6->dst.plen;
436 frh->src_len = rule6->src.plen;
437 frh->tos = inet_dscp_to_dsfield(rule6->dscp);
438
439 if ((rule6->dst.plen &&
440 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
441 (rule6->src.plen &&
442 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
443 goto nla_put_failure;
444 return 0;
445
446 nla_put_failure:
447 return -ENOBUFS;
448 }
449
450 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
451 {
452 return nla_total_size(16) /* dst */
453 + nla_total_size(16); /* src */
454 }
455
456 static void fib6_rule_flush_cache(struct fib_rules_ops *ops)
457 {
458 rt_genid_bump_ipv6(ops->fro_net);
459 }
460
461 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
462 .family = AF_INET6,
463 .rule_size = sizeof(struct fib6_rule),
464 .addr_size = sizeof(struct in6_addr),
465 .action = fib6_rule_action,
466 .match = fib6_rule_match,
467 .suppress = fib6_rule_suppress,
468 .configure = fib6_rule_configure,
469 .delete = fib6_rule_delete,
470 .compare = fib6_rule_compare,
471 .fill = fib6_rule_fill,
472 .nlmsg_payload = fib6_rule_nlmsg_payload,
473 .flush_cache = fib6_rule_flush_cache,
474 .nlgroup = RTNLGRP_IPV6_RULE,
475 .owner = THIS_MODULE,
476 .fro_net = &init_net,
477 };
478
479 static int __net_init fib6_rules_net_init(struct net *net)
480 {
481 struct fib_rules_ops *ops;
482 int err;
483
484 ops = fib_rules_register(&fib6_rules_ops_template, net);
485 if (IS_ERR(ops))
486 return PTR_ERR(ops);
487
488 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL);
489 if (err)
490 goto out_fib6_rules_ops;
491
492 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN);
493 if (err)
494 goto out_fib6_rules_ops;
495
496 net->ipv6.fib6_rules_ops = ops;
497 net->ipv6.fib6_rules_require_fldissect = 0;
498 out:
499 return err;
500
501 out_fib6_rules_ops:
502 fib_rules_unregister(ops);
503 goto out;
504 }
505
506 static void __net_exit fib6_rules_net_exit_batch(struct list_head *net_list)
507 {
508 struct net *net;
509
510 rtnl_lock();
511 list_for_each_entry(net, net_list, exit_list) {
512 fib_rules_unregister(net->ipv6.fib6_rules_ops);
513 cond_resched();
514 }
515 rtnl_unlock();
516 }
517
518 static struct pernet_operations fib6_rules_net_ops = {
519 .init = fib6_rules_net_init,
520 .exit_batch = fib6_rules_net_exit_batch,
521 };
522
523 int __init fib6_rules_init(void)
524 {
525 return register_pernet_subsys(&fib6_rules_net_ops);
526 }
527
528
529 void fib6_rules_cleanup(void)
530 {
531 unregister_pernet_subsys(&fib6_rules_net_ops);
532 }
533
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.