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, fl: 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, table: net->ipv6.fib6_local_tbl, oif, |
83 | fl6, res, strict: flags); |
84 | if (err || res->f6i == net->ipv6.fib6_null_entry) |
85 | err = fib6_table_lookup(net, table: net->ipv6.fib6_main_tbl, |
86 | oif, fl6, res, strict: 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, fl: 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, table: 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, table: 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(dst: &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, daddr: &flp6->daddr, |
146 | srcprefs: rt6_flags2srcprefs(flags), saddr: &saddr)) |
147 | return -EAGAIN; |
148 | |
149 | if (!ipv6_prefix_equal(addr1: &saddr, addr2: &r->src.addr, prefixlen: 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, id: tb_id); |
182 | if (!table) |
183 | return -EAGAIN; |
184 | |
185 | oif = (int *)arg->lookup_data; |
186 | err = fib6_table_lookup(net, table, oif: *oif, fl6: flp6, res, strict: flags); |
187 | if (!err && res->f6i != net->ipv6.fib6_null_entry) |
188 | err = fib6_rule_saddr(net, rule, flags, flp6, |
189 | dev: 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, id: tb_id); |
228 | if (!table) { |
229 | err = -EAGAIN; |
230 | goto out; |
231 | } |
232 | |
233 | rt = pol_lookup_func(lookup, |
234 | net, table, fl6: flp6, skb: arg->lookup_data, flags); |
235 | if (rt != net->ipv6.ip6_null_entry) { |
236 | err = fib6_rule_saddr(net, rule, flags, flp6, |
237 | dev: ip6_dst_idev(dst: &rt->dst)->dev); |
238 | |
239 | if (err == -EAGAIN) |
240 | goto again; |
241 | |
242 | err = rt->dst.error; |
243 | if (err != -EAGAIN) |
244 | goto out; |
245 | } |
246 | again: |
247 | ip6_rt_put_flags(rt, flags); |
248 | err = -EAGAIN; |
249 | rt = NULL; |
250 | goto out; |
251 | |
252 | discard_pkt: |
253 | if (!(flags & RT6_LOOKUP_F_DST_NOREF)) |
254 | dst_hold(dst: &rt->dst); |
255 | out: |
256 | res->rt6 = rt; |
257 | return err; |
258 | } |
259 | |
260 | INDIRECT_CALLABLE_SCOPE int fib6_rule_action(struct fib_rule *rule, |
261 | struct flowi *flp, int flags, |
262 | struct fib_lookup_arg *arg) |
263 | { |
264 | if (arg->lookup_ptr == fib6_table_lookup) |
265 | return fib6_rule_action_alt(rule, flp, flags, arg); |
266 | |
267 | return __fib6_rule_action(rule, flp, flags, arg); |
268 | } |
269 | |
270 | INDIRECT_CALLABLE_SCOPE bool fib6_rule_suppress(struct fib_rule *rule, |
271 | int flags, |
272 | struct fib_lookup_arg *arg) |
273 | { |
274 | struct fib6_result *res = arg->result; |
275 | struct rt6_info *rt = res->rt6; |
276 | struct net_device *dev = NULL; |
277 | |
278 | if (!rt) |
279 | return false; |
280 | |
281 | if (rt->rt6i_idev) |
282 | dev = rt->rt6i_idev->dev; |
283 | |
284 | /* do not accept result if the route does |
285 | * not meet the required prefix length |
286 | */ |
287 | if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) |
288 | goto suppress_route; |
289 | |
290 | /* do not accept result if the route uses a device |
291 | * belonging to a forbidden interface group |
292 | */ |
293 | if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) |
294 | goto suppress_route; |
295 | |
296 | return false; |
297 | |
298 | suppress_route: |
299 | ip6_rt_put_flags(rt, flags); |
300 | return true; |
301 | } |
302 | |
303 | INDIRECT_CALLABLE_SCOPE int fib6_rule_match(struct fib_rule *rule, |
304 | struct flowi *fl, int flags) |
305 | { |
306 | struct fib6_rule *r = (struct fib6_rule *) rule; |
307 | struct flowi6 *fl6 = &fl->u.ip6; |
308 | |
309 | if (r->dst.plen && |
310 | !ipv6_prefix_equal(addr1: &fl6->daddr, addr2: &r->dst.addr, prefixlen: r->dst.plen)) |
311 | return 0; |
312 | |
313 | /* |
314 | * If FIB_RULE_FIND_SADDR is set and we do not have a |
315 | * source address for the traffic, we defer check for |
316 | * source address. |
317 | */ |
318 | if (r->src.plen) { |
319 | if (flags & RT6_LOOKUP_F_HAS_SADDR) { |
320 | if (!ipv6_prefix_equal(addr1: &fl6->saddr, addr2: &r->src.addr, |
321 | prefixlen: r->src.plen)) |
322 | return 0; |
323 | } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) |
324 | return 0; |
325 | } |
326 | |
327 | if (r->dscp && r->dscp != ip6_dscp(flowinfo: fl6->flowlabel)) |
328 | return 0; |
329 | |
330 | if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) |
331 | return 0; |
332 | |
333 | if (fib_rule_port_range_set(range: &rule->sport_range) && |
334 | !fib_rule_port_inrange(a: &rule->sport_range, port: fl6->fl6_sport)) |
335 | return 0; |
336 | |
337 | if (fib_rule_port_range_set(range: &rule->dport_range) && |
338 | !fib_rule_port_inrange(a: &rule->dport_range, port: fl6->fl6_dport)) |
339 | return 0; |
340 | |
341 | return 1; |
342 | } |
343 | |
344 | static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, |
345 | struct fib_rule_hdr *frh, |
346 | struct nlattr **tb, |
347 | struct netlink_ext_ack *extack) |
348 | { |
349 | int err = -EINVAL; |
350 | struct net *net = sock_net(sk: skb->sk); |
351 | struct fib6_rule *rule6 = (struct fib6_rule *) rule; |
352 | |
353 | if (!inet_validate_dscp(val: frh->tos)) { |
354 | NL_SET_ERR_MSG(extack, |
355 | "Invalid dsfield (tos): ECN bits must be 0" ); |
356 | goto errout; |
357 | } |
358 | rule6->dscp = inet_dsfield_to_dscp(dsfield: frh->tos); |
359 | |
360 | if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { |
361 | if (rule->table == RT6_TABLE_UNSPEC) { |
362 | NL_SET_ERR_MSG(extack, "Invalid table" ); |
363 | goto errout; |
364 | } |
365 | |
366 | if (fib6_new_table(net, id: rule->table) == NULL) { |
367 | err = -ENOBUFS; |
368 | goto errout; |
369 | } |
370 | } |
371 | |
372 | if (frh->src_len) |
373 | rule6->src.addr = nla_get_in6_addr(nla: tb[FRA_SRC]); |
374 | |
375 | if (frh->dst_len) |
376 | rule6->dst.addr = nla_get_in6_addr(nla: tb[FRA_DST]); |
377 | |
378 | rule6->src.plen = frh->src_len; |
379 | rule6->dst.plen = frh->dst_len; |
380 | |
381 | if (fib_rule_requires_fldissect(rule)) |
382 | net->ipv6.fib6_rules_require_fldissect++; |
383 | |
384 | net->ipv6.fib6_has_custom_rules = true; |
385 | err = 0; |
386 | errout: |
387 | return err; |
388 | } |
389 | |
390 | static int fib6_rule_delete(struct fib_rule *rule) |
391 | { |
392 | struct net *net = rule->fr_net; |
393 | |
394 | if (net->ipv6.fib6_rules_require_fldissect && |
395 | fib_rule_requires_fldissect(rule)) |
396 | net->ipv6.fib6_rules_require_fldissect--; |
397 | |
398 | return 0; |
399 | } |
400 | |
401 | static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, |
402 | struct nlattr **tb) |
403 | { |
404 | struct fib6_rule *rule6 = (struct fib6_rule *) rule; |
405 | |
406 | if (frh->src_len && (rule6->src.plen != frh->src_len)) |
407 | return 0; |
408 | |
409 | if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) |
410 | return 0; |
411 | |
412 | if (frh->tos && inet_dscp_to_dsfield(dscp: rule6->dscp) != frh->tos) |
413 | return 0; |
414 | |
415 | if (frh->src_len && |
416 | nla_memcmp(nla: tb[FRA_SRC], data: &rule6->src.addr, size: sizeof(struct in6_addr))) |
417 | return 0; |
418 | |
419 | if (frh->dst_len && |
420 | nla_memcmp(nla: tb[FRA_DST], data: &rule6->dst.addr, size: sizeof(struct in6_addr))) |
421 | return 0; |
422 | |
423 | return 1; |
424 | } |
425 | |
426 | static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, |
427 | struct fib_rule_hdr *frh) |
428 | { |
429 | struct fib6_rule *rule6 = (struct fib6_rule *) rule; |
430 | |
431 | frh->dst_len = rule6->dst.plen; |
432 | frh->src_len = rule6->src.plen; |
433 | frh->tos = inet_dscp_to_dsfield(dscp: rule6->dscp); |
434 | |
435 | if ((rule6->dst.plen && |
436 | nla_put_in6_addr(skb, attrtype: FRA_DST, addr: &rule6->dst.addr)) || |
437 | (rule6->src.plen && |
438 | nla_put_in6_addr(skb, attrtype: FRA_SRC, addr: &rule6->src.addr))) |
439 | goto nla_put_failure; |
440 | return 0; |
441 | |
442 | nla_put_failure: |
443 | return -ENOBUFS; |
444 | } |
445 | |
446 | static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) |
447 | { |
448 | return nla_total_size(payload: 16) /* dst */ |
449 | + nla_total_size(payload: 16); /* src */ |
450 | } |
451 | |
452 | static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { |
453 | .family = AF_INET6, |
454 | .rule_size = sizeof(struct fib6_rule), |
455 | .addr_size = sizeof(struct in6_addr), |
456 | .action = fib6_rule_action, |
457 | .match = fib6_rule_match, |
458 | .suppress = fib6_rule_suppress, |
459 | .configure = fib6_rule_configure, |
460 | .delete = fib6_rule_delete, |
461 | .compare = fib6_rule_compare, |
462 | .fill = fib6_rule_fill, |
463 | .nlmsg_payload = fib6_rule_nlmsg_payload, |
464 | .nlgroup = RTNLGRP_IPV6_RULE, |
465 | .owner = THIS_MODULE, |
466 | .fro_net = &init_net, |
467 | }; |
468 | |
469 | static int __net_init fib6_rules_net_init(struct net *net) |
470 | { |
471 | struct fib_rules_ops *ops; |
472 | int err; |
473 | |
474 | ops = fib_rules_register(&fib6_rules_ops_template, net); |
475 | if (IS_ERR(ptr: ops)) |
476 | return PTR_ERR(ptr: ops); |
477 | |
478 | err = fib_default_rule_add(ops, pref: 0, RT6_TABLE_LOCAL, flags: 0); |
479 | if (err) |
480 | goto out_fib6_rules_ops; |
481 | |
482 | err = fib_default_rule_add(ops, pref: 0x7FFE, RT6_TABLE_MAIN, flags: 0); |
483 | if (err) |
484 | goto out_fib6_rules_ops; |
485 | |
486 | net->ipv6.fib6_rules_ops = ops; |
487 | net->ipv6.fib6_rules_require_fldissect = 0; |
488 | out: |
489 | return err; |
490 | |
491 | out_fib6_rules_ops: |
492 | fib_rules_unregister(ops); |
493 | goto out; |
494 | } |
495 | |
496 | static void __net_exit fib6_rules_net_exit_batch(struct list_head *net_list) |
497 | { |
498 | struct net *net; |
499 | |
500 | rtnl_lock(); |
501 | list_for_each_entry(net, net_list, exit_list) { |
502 | fib_rules_unregister(net->ipv6.fib6_rules_ops); |
503 | cond_resched(); |
504 | } |
505 | rtnl_unlock(); |
506 | } |
507 | |
508 | static struct pernet_operations fib6_rules_net_ops = { |
509 | .init = fib6_rules_net_init, |
510 | .exit_batch = fib6_rules_net_exit_batch, |
511 | }; |
512 | |
513 | int __init fib6_rules_init(void) |
514 | { |
515 | return register_pernet_subsys(&fib6_rules_net_ops); |
516 | } |
517 | |
518 | |
519 | void fib6_rules_cleanup(void) |
520 | { |
521 | unregister_pernet_subsys(&fib6_rules_net_ops); |
522 | } |
523 | |