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/ipv6.h>
20 #include <net/addrconf.h>
21 #include <net/ip6_route.h>
22 #include <net/netlink.h>
23
24 struct fib6_rule {
25 struct fib_rule common;
26 struct rt6key src;
27 struct rt6key dst;
28 u8 tclass;
29 };
30
fib6_rule_matchall(const struct fib_rule * rule)31 static bool fib6_rule_matchall(const struct fib_rule *rule)
32 {
33 struct fib6_rule *r = container_of(rule, struct fib6_rule, common);
34
35 if (r->dst.plen || r->src.plen || r->tclass)
36 return false;
37 return fib_rule_matchall(rule);
38 }
39
fib6_rule_default(const struct fib_rule * rule)40 bool fib6_rule_default(const struct fib_rule *rule)
41 {
42 if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
43 rule->l3mdev)
44 return false;
45 if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
46 return false;
47 return true;
48 }
49 EXPORT_SYMBOL_GPL(fib6_rule_default);
50
fib6_rules_dump(struct net * net,struct notifier_block * nb,struct netlink_ext_ack * extack)51 int fib6_rules_dump(struct net *net, struct notifier_block *nb,
52 struct netlink_ext_ack *extack)
53 {
54 return fib_rules_dump(net, nb, AF_INET6, extack);
55 }
56
fib6_rules_seq_read(struct net * net)57 unsigned int fib6_rules_seq_read(struct net *net)
58 {
59 return fib_rules_seq_read(net, AF_INET6);
60 }
61
62 /* called with rcu lock held; no reference taken on fib6_info */
fib6_lookup(struct net * net,int oif,struct flowi6 * fl6,struct fib6_result * res,int flags)63 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
64 struct fib6_result *res, int flags)
65 {
66 int err;
67
68 if (net->ipv6.fib6_has_custom_rules) {
69 struct fib_lookup_arg arg = {
70 .lookup_ptr = fib6_table_lookup,
71 .lookup_data = &oif,
72 .result = res,
73 .flags = FIB_LOOKUP_NOREF,
74 };
75
76 l3mdev_update_flow(net, flowi6_to_flowi(fl6));
77
78 err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
79 flowi6_to_flowi(fl6), flags, &arg);
80 } else {
81 err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
82 fl6, res, flags);
83 if (err || res->f6i == net->ipv6.fib6_null_entry)
84 err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
85 oif, fl6, res, flags);
86 }
87
88 return err;
89 }
90
fib6_rule_lookup(struct net * net,struct flowi6 * fl6,const struct sk_buff * skb,int flags,pol_lookup_t lookup)91 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
92 const struct sk_buff *skb,
93 int flags, pol_lookup_t lookup)
94 {
95 if (net->ipv6.fib6_has_custom_rules) {
96 struct fib6_result res = {};
97 struct fib_lookup_arg arg = {
98 .lookup_ptr = lookup,
99 .lookup_data = skb,
100 .result = &res,
101 .flags = FIB_LOOKUP_NOREF,
102 };
103
104 /* update flow if oif or iif point to device enslaved to l3mdev */
105 l3mdev_update_flow(net, flowi6_to_flowi(fl6));
106
107 fib_rules_lookup(net->ipv6.fib6_rules_ops,
108 flowi6_to_flowi(fl6), flags, &arg);
109
110 if (res.rt6)
111 return &res.rt6->dst;
112 } else {
113 struct rt6_info *rt;
114
115 rt = pol_lookup_func(lookup,
116 net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
117 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
118 return &rt->dst;
119 ip6_rt_put_flags(rt, flags);
120 rt = pol_lookup_func(lookup,
121 net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
122 if (rt->dst.error != -EAGAIN)
123 return &rt->dst;
124 ip6_rt_put_flags(rt, flags);
125 }
126
127 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
128 dst_hold(&net->ipv6.ip6_null_entry->dst);
129 return &net->ipv6.ip6_null_entry->dst;
130 }
131
fib6_rule_saddr(struct net * net,struct fib_rule * rule,int flags,struct flowi6 * flp6,const struct net_device * dev)132 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags,
133 struct flowi6 *flp6, const struct net_device *dev)
134 {
135 struct fib6_rule *r = (struct fib6_rule *)rule;
136
137 /* If we need to find a source address for this traffic,
138 * we check the result if it meets requirement of the rule.
139 */
140 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
141 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
142 struct in6_addr saddr;
143
144 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr,
145 rt6_flags2srcprefs(flags), &saddr))
146 return -EAGAIN;
147
148 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen))
149 return -EAGAIN;
150
151 flp6->saddr = saddr;
152 }
153
154 return 0;
155 }
156
fib6_rule_action_alt(struct fib_rule * rule,struct flowi * flp,int flags,struct fib_lookup_arg * arg)157 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
158 int flags, struct fib_lookup_arg *arg)
159 {
160 struct fib6_result *res = arg->result;
161 struct flowi6 *flp6 = &flp->u.ip6;
162 struct net *net = rule->fr_net;
163 struct fib6_table *table;
164 int err, *oif;
165 u32 tb_id;
166
167 switch (rule->action) {
168 case FR_ACT_TO_TBL:
169 break;
170 case FR_ACT_UNREACHABLE:
171 return -ENETUNREACH;
172 case FR_ACT_PROHIBIT:
173 return -EACCES;
174 case FR_ACT_BLACKHOLE:
175 default:
176 return -EINVAL;
177 }
178
179 tb_id = fib_rule_get_table(rule, arg);
180 table = fib6_get_table(net, tb_id);
181 if (!table)
182 return -EAGAIN;
183
184 oif = (int *)arg->lookup_data;
185 err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
186 if (!err && res->f6i != net->ipv6.fib6_null_entry)
187 err = fib6_rule_saddr(net, rule, flags, flp6,
188 res->nh->fib_nh_dev);
189 else
190 err = -EAGAIN;
191
192 return err;
193 }
194
__fib6_rule_action(struct fib_rule * rule,struct flowi * flp,int flags,struct fib_lookup_arg * arg)195 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
196 int flags, struct fib_lookup_arg *arg)
197 {
198 struct fib6_result *res = arg->result;
199 struct flowi6 *flp6 = &flp->u.ip6;
200 struct rt6_info *rt = NULL;
201 struct fib6_table *table;
202 struct net *net = rule->fr_net;
203 pol_lookup_t lookup = arg->lookup_ptr;
204 int err = 0;
205 u32 tb_id;
206
207 switch (rule->action) {
208 case FR_ACT_TO_TBL:
209 break;
210 case FR_ACT_UNREACHABLE:
211 err = -ENETUNREACH;
212 rt = net->ipv6.ip6_null_entry;
213 goto discard_pkt;
214 default:
215 case FR_ACT_BLACKHOLE:
216 err = -EINVAL;
217 rt = net->ipv6.ip6_blk_hole_entry;
218 goto discard_pkt;
219 case FR_ACT_PROHIBIT:
220 err = -EACCES;
221 rt = net->ipv6.ip6_prohibit_entry;
222 goto discard_pkt;
223 }
224
225 tb_id = fib_rule_get_table(rule, arg);
226 table = fib6_get_table(net, tb_id);
227 if (!table) {
228 err = -EAGAIN;
229 goto out;
230 }
231
232 rt = pol_lookup_func(lookup,
233 net, table, flp6, arg->lookup_data, flags);
234 if (rt != net->ipv6.ip6_null_entry) {
235 err = fib6_rule_saddr(net, rule, flags, flp6,
236 ip6_dst_idev(&rt->dst)->dev);
237
238 if (err == -EAGAIN)
239 goto again;
240
241 err = rt->dst.error;
242 if (err != -EAGAIN)
243 goto out;
244 }
245 again:
246 ip6_rt_put_flags(rt, flags);
247 err = -EAGAIN;
248 rt = NULL;
249 goto out;
250
251 discard_pkt:
252 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
253 dst_hold(&rt->dst);
254 out:
255 res->rt6 = rt;
256 return err;
257 }
258
fib6_rule_action(struct fib_rule * rule,struct flowi * flp,int flags,struct fib_lookup_arg * arg)259 INDIRECT_CALLABLE_SCOPE int fib6_rule_action(struct fib_rule *rule,
260 struct flowi *flp, int flags,
261 struct fib_lookup_arg *arg)
262 {
263 if (arg->lookup_ptr == fib6_table_lookup)
264 return fib6_rule_action_alt(rule, flp, flags, arg);
265
266 return __fib6_rule_action(rule, flp, flags, arg);
267 }
268
fib6_rule_suppress(struct fib_rule * rule,int flags,struct fib_lookup_arg * arg)269 INDIRECT_CALLABLE_SCOPE bool fib6_rule_suppress(struct fib_rule *rule,
270 int flags,
271 struct fib_lookup_arg *arg)
272 {
273 struct fib6_result *res = arg->result;
274 struct rt6_info *rt = res->rt6;
275 struct net_device *dev = NULL;
276
277 if (!rt)
278 return false;
279
280 if (rt->rt6i_idev)
281 dev = rt->rt6i_idev->dev;
282
283 /* do not accept result if the route does
284 * not meet the required prefix length
285 */
286 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
287 goto suppress_route;
288
289 /* do not accept result if the route uses a device
290 * belonging to a forbidden interface group
291 */
292 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
293 goto suppress_route;
294
295 return false;
296
297 suppress_route:
298 ip6_rt_put_flags(rt, flags);
299 return true;
300 }
301
fib6_rule_match(struct fib_rule * rule,struct flowi * fl,int flags)302 INDIRECT_CALLABLE_SCOPE int fib6_rule_match(struct fib_rule *rule,
303 struct flowi *fl, int flags)
304 {
305 struct fib6_rule *r = (struct fib6_rule *) rule;
306 struct flowi6 *fl6 = &fl->u.ip6;
307
308 if (r->dst.plen &&
309 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
310 return 0;
311
312 /*
313 * If FIB_RULE_FIND_SADDR is set and we do not have a
314 * source address for the traffic, we defer check for
315 * source address.
316 */
317 if (r->src.plen) {
318 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
319 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
320 r->src.plen))
321 return 0;
322 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
323 return 0;
324 }
325
326 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel))
327 return 0;
328
329 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
330 return 0;
331
332 if (fib_rule_port_range_set(&rule->sport_range) &&
333 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
334 return 0;
335
336 if (fib_rule_port_range_set(&rule->dport_range) &&
337 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
338 return 0;
339
340 return 1;
341 }
342
343 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
344 FRA_GENERIC_POLICY,
345 };
346
fib6_rule_configure(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh,struct nlattr ** tb,struct netlink_ext_ack * extack)347 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
348 struct fib_rule_hdr *frh,
349 struct nlattr **tb,
350 struct netlink_ext_ack *extack)
351 {
352 int err = -EINVAL;
353 struct net *net = sock_net(skb->sk);
354 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
355
356 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
357 if (rule->table == RT6_TABLE_UNSPEC) {
358 NL_SET_ERR_MSG(extack, "Invalid table");
359 goto errout;
360 }
361
362 if (fib6_new_table(net, rule->table) == NULL) {
363 err = -ENOBUFS;
364 goto errout;
365 }
366 }
367
368 if (frh->src_len)
369 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);
370
371 if (frh->dst_len)
372 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);
373
374 rule6->src.plen = frh->src_len;
375 rule6->dst.plen = frh->dst_len;
376 rule6->tclass = frh->tos;
377
378 if (fib_rule_requires_fldissect(rule))
379 net->ipv6.fib6_rules_require_fldissect++;
380
381 net->ipv6.fib6_has_custom_rules = true;
382 err = 0;
383 errout:
384 return err;
385 }
386
fib6_rule_delete(struct fib_rule * rule)387 static int fib6_rule_delete(struct fib_rule *rule)
388 {
389 struct net *net = rule->fr_net;
390
391 if (net->ipv6.fib6_rules_require_fldissect &&
392 fib_rule_requires_fldissect(rule))
393 net->ipv6.fib6_rules_require_fldissect--;
394
395 return 0;
396 }
397
fib6_rule_compare(struct fib_rule * rule,struct fib_rule_hdr * frh,struct nlattr ** tb)398 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
399 struct nlattr **tb)
400 {
401 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
402
403 if (frh->src_len && (rule6->src.plen != frh->src_len))
404 return 0;
405
406 if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
407 return 0;
408
409 if (frh->tos && (rule6->tclass != frh->tos))
410 return 0;
411
412 if (frh->src_len &&
413 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
414 return 0;
415
416 if (frh->dst_len &&
417 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
418 return 0;
419
420 return 1;
421 }
422
fib6_rule_fill(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh)423 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
424 struct fib_rule_hdr *frh)
425 {
426 struct fib6_rule *rule6 = (struct fib6_rule *) rule;
427
428 frh->dst_len = rule6->dst.plen;
429 frh->src_len = rule6->src.plen;
430 frh->tos = rule6->tclass;
431
432 if ((rule6->dst.plen &&
433 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
434 (rule6->src.plen &&
435 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
436 goto nla_put_failure;
437 return 0;
438
439 nla_put_failure:
440 return -ENOBUFS;
441 }
442
fib6_rule_nlmsg_payload(struct fib_rule * rule)443 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
444 {
445 return nla_total_size(16) /* dst */
446 + nla_total_size(16); /* src */
447 }
448
449 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
450 .family = AF_INET6,
451 .rule_size = sizeof(struct fib6_rule),
452 .addr_size = sizeof(struct in6_addr),
453 .action = fib6_rule_action,
454 .match = fib6_rule_match,
455 .suppress = fib6_rule_suppress,
456 .configure = fib6_rule_configure,
457 .delete = fib6_rule_delete,
458 .compare = fib6_rule_compare,
459 .fill = fib6_rule_fill,
460 .nlmsg_payload = fib6_rule_nlmsg_payload,
461 .nlgroup = RTNLGRP_IPV6_RULE,
462 .policy = fib6_rule_policy,
463 .owner = THIS_MODULE,
464 .fro_net = &init_net,
465 };
466
fib6_rules_net_init(struct net * net)467 static int __net_init fib6_rules_net_init(struct net *net)
468 {
469 struct fib_rules_ops *ops;
470 int err = -ENOMEM;
471
472 ops = fib_rules_register(&fib6_rules_ops_template, net);
473 if (IS_ERR(ops))
474 return PTR_ERR(ops);
475
476 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
477 if (err)
478 goto out_fib6_rules_ops;
479
480 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
481 if (err)
482 goto out_fib6_rules_ops;
483
484 net->ipv6.fib6_rules_ops = ops;
485 net->ipv6.fib6_rules_require_fldissect = 0;
486 out:
487 return err;
488
489 out_fib6_rules_ops:
490 fib_rules_unregister(ops);
491 goto out;
492 }
493
fib6_rules_net_exit(struct net * net)494 static void __net_exit fib6_rules_net_exit(struct net *net)
495 {
496 rtnl_lock();
497 fib_rules_unregister(net->ipv6.fib6_rules_ops);
498 rtnl_unlock();
499 }
500
501 static struct pernet_operations fib6_rules_net_ops = {
502 .init = fib6_rules_net_init,
503 .exit = fib6_rules_net_exit,
504 };
505
fib6_rules_init(void)506 int __init fib6_rules_init(void)
507 {
508 return register_pernet_subsys(&fib6_rules_net_ops);
509 }
510
511
fib6_rules_cleanup(void)512 void fib6_rules_cleanup(void)
513 {
514 unregister_pernet_subsys(&fib6_rules_net_ops);
515 }
516