1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: FIB frontend.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/module.h>
13 #include <linux/uaccess.h>
14 #include <linux/bitops.h>
15 #include <linux/capability.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/string.h>
20 #include <linux/socket.h>
21 #include <linux/sockios.h>
22 #include <linux/errno.h>
23 #include <linux/in.h>
24 #include <linux/inet.h>
25 #include <linux/inetdevice.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_addr.h>
28 #include <linux/if_arp.h>
29 #include <linux/skbuff.h>
30 #include <linux/cache.h>
31 #include <linux/init.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34
35 #include <net/ip.h>
36 #include <net/protocol.h>
37 #include <net/route.h>
38 #include <net/tcp.h>
39 #include <net/sock.h>
40 #include <net/arp.h>
41 #include <net/ip_fib.h>
42 #include <net/nexthop.h>
43 #include <net/rtnetlink.h>
44 #include <net/xfrm.h>
45 #include <net/l3mdev.h>
46 #include <net/lwtunnel.h>
47 #include <trace/events/fib.h>
48
49 #ifndef CONFIG_IP_MULTIPLE_TABLES
50
fib4_rules_init(struct net * net)51 static int __net_init fib4_rules_init(struct net *net)
52 {
53 struct fib_table *local_table, *main_table;
54
55 main_table = fib_trie_table(RT_TABLE_MAIN, NULL);
56 if (!main_table)
57 return -ENOMEM;
58
59 local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
60 if (!local_table)
61 goto fail;
62
63 hlist_add_head_rcu(&local_table->tb_hlist,
64 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
65 hlist_add_head_rcu(&main_table->tb_hlist,
66 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
67 return 0;
68
69 fail:
70 fib_free_table(main_table);
71 return -ENOMEM;
72 }
73 #else
74
fib_new_table(struct net * net,u32 id)75 struct fib_table *fib_new_table(struct net *net, u32 id)
76 {
77 struct fib_table *tb, *alias = NULL;
78 unsigned int h;
79
80 if (id == 0)
81 id = RT_TABLE_MAIN;
82 tb = fib_get_table(net, id);
83 if (tb)
84 return tb;
85
86 if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
87 alias = fib_new_table(net, RT_TABLE_MAIN);
88
89 tb = fib_trie_table(id, alias);
90 if (!tb)
91 return NULL;
92
93 switch (id) {
94 case RT_TABLE_MAIN:
95 rcu_assign_pointer(net->ipv4.fib_main, tb);
96 break;
97 case RT_TABLE_DEFAULT:
98 rcu_assign_pointer(net->ipv4.fib_default, tb);
99 break;
100 default:
101 break;
102 }
103
104 h = id & (FIB_TABLE_HASHSZ - 1);
105 hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
106 return tb;
107 }
108 EXPORT_SYMBOL_GPL(fib_new_table);
109
110 /* caller must hold either rtnl or rcu read lock */
fib_get_table(struct net * net,u32 id)111 struct fib_table *fib_get_table(struct net *net, u32 id)
112 {
113 struct fib_table *tb;
114 struct hlist_head *head;
115 unsigned int h;
116
117 if (id == 0)
118 id = RT_TABLE_MAIN;
119 h = id & (FIB_TABLE_HASHSZ - 1);
120
121 head = &net->ipv4.fib_table_hash[h];
122 hlist_for_each_entry_rcu(tb, head, tb_hlist,
123 lockdep_rtnl_is_held()) {
124 if (tb->tb_id == id)
125 return tb;
126 }
127 return NULL;
128 }
129 #endif /* CONFIG_IP_MULTIPLE_TABLES */
130
fib_replace_table(struct net * net,struct fib_table * old,struct fib_table * new)131 static void fib_replace_table(struct net *net, struct fib_table *old,
132 struct fib_table *new)
133 {
134 #ifdef CONFIG_IP_MULTIPLE_TABLES
135 switch (new->tb_id) {
136 case RT_TABLE_MAIN:
137 rcu_assign_pointer(net->ipv4.fib_main, new);
138 break;
139 case RT_TABLE_DEFAULT:
140 rcu_assign_pointer(net->ipv4.fib_default, new);
141 break;
142 default:
143 break;
144 }
145
146 #endif
147 /* replace the old table in the hlist */
148 hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
149 }
150
fib_unmerge(struct net * net)151 int fib_unmerge(struct net *net)
152 {
153 struct fib_table *old, *new, *main_table;
154
155 /* attempt to fetch local table if it has been allocated */
156 old = fib_get_table(net, RT_TABLE_LOCAL);
157 if (!old)
158 return 0;
159
160 new = fib_trie_unmerge(old);
161 if (!new)
162 return -ENOMEM;
163
164 /* table is already unmerged */
165 if (new == old)
166 return 0;
167
168 /* replace merged table with clean table */
169 fib_replace_table(net, old, new);
170 fib_free_table(old);
171
172 /* attempt to fetch main table if it has been allocated */
173 main_table = fib_get_table(net, RT_TABLE_MAIN);
174 if (!main_table)
175 return 0;
176
177 /* flush local entries from main table */
178 fib_table_flush_external(main_table);
179
180 return 0;
181 }
182
fib_flush(struct net * net)183 void fib_flush(struct net *net)
184 {
185 int flushed = 0;
186 unsigned int h;
187
188 for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
189 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
190 struct hlist_node *tmp;
191 struct fib_table *tb;
192
193 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
194 flushed += fib_table_flush(net, tb, false);
195 }
196
197 if (flushed)
198 rt_cache_flush(net);
199 }
200
201 /*
202 * Find address type as if only "dev" was present in the system. If
203 * on_dev is NULL then all interfaces are taken into consideration.
204 */
__inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr,u32 tb_id)205 static inline unsigned int __inet_dev_addr_type(struct net *net,
206 const struct net_device *dev,
207 __be32 addr, u32 tb_id)
208 {
209 struct flowi4 fl4 = { .daddr = addr };
210 struct fib_result res;
211 unsigned int ret = RTN_BROADCAST;
212 struct fib_table *table;
213
214 if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
215 return RTN_BROADCAST;
216 if (ipv4_is_multicast(addr))
217 return RTN_MULTICAST;
218
219 rcu_read_lock();
220
221 table = fib_get_table(net, tb_id);
222 if (table) {
223 ret = RTN_UNICAST;
224 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
225 struct fib_nh_common *nhc = fib_info_nhc(res.fi, 0);
226
227 if (!dev || dev == nhc->nhc_dev)
228 ret = res.type;
229 }
230 }
231
232 rcu_read_unlock();
233 return ret;
234 }
235
inet_addr_type_table(struct net * net,__be32 addr,u32 tb_id)236 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
237 {
238 return __inet_dev_addr_type(net, NULL, addr, tb_id);
239 }
240 EXPORT_SYMBOL(inet_addr_type_table);
241
inet_addr_type(struct net * net,__be32 addr)242 unsigned int inet_addr_type(struct net *net, __be32 addr)
243 {
244 return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
245 }
246 EXPORT_SYMBOL(inet_addr_type);
247
inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr)248 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
249 __be32 addr)
250 {
251 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
252
253 return __inet_dev_addr_type(net, dev, addr, rt_table);
254 }
255 EXPORT_SYMBOL(inet_dev_addr_type);
256
257 /* inet_addr_type with dev == NULL but using the table from a dev
258 * if one is associated
259 */
inet_addr_type_dev_table(struct net * net,const struct net_device * dev,__be32 addr)260 unsigned int inet_addr_type_dev_table(struct net *net,
261 const struct net_device *dev,
262 __be32 addr)
263 {
264 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
265
266 return __inet_dev_addr_type(net, NULL, addr, rt_table);
267 }
268 EXPORT_SYMBOL(inet_addr_type_dev_table);
269
fib_compute_spec_dst(struct sk_buff * skb)270 __be32 fib_compute_spec_dst(struct sk_buff *skb)
271 {
272 struct net_device *dev = skb->dev;
273 struct in_device *in_dev;
274 struct fib_result res;
275 struct rtable *rt;
276 struct net *net;
277 int scope;
278
279 rt = skb_rtable(skb);
280 if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
281 RTCF_LOCAL)
282 return ip_hdr(skb)->daddr;
283
284 in_dev = __in_dev_get_rcu(dev);
285
286 net = dev_net(dev);
287
288 scope = RT_SCOPE_UNIVERSE;
289 if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
290 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
291 struct flowi4 fl4 = {
292 .flowi4_iif = LOOPBACK_IFINDEX,
293 .flowi4_oif = l3mdev_master_ifindex_rcu(dev),
294 .daddr = ip_hdr(skb)->saddr,
295 .flowi4_tos = ip_hdr(skb)->tos & IPTOS_RT_MASK,
296 .flowi4_scope = scope,
297 .flowi4_mark = vmark ? skb->mark : 0,
298 };
299 if (!fib_lookup(net, &fl4, &res, 0))
300 return fib_result_prefsrc(net, &res);
301 } else {
302 scope = RT_SCOPE_LINK;
303 }
304
305 return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
306 }
307
fib_info_nh_uses_dev(struct fib_info * fi,const struct net_device * dev)308 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
309 {
310 bool dev_match = false;
311 #ifdef CONFIG_IP_ROUTE_MULTIPATH
312 if (unlikely(fi->nh)) {
313 dev_match = nexthop_uses_dev(fi->nh, dev);
314 } else {
315 int ret;
316
317 for (ret = 0; ret < fib_info_num_path(fi); ret++) {
318 const struct fib_nh_common *nhc = fib_info_nhc(fi, ret);
319
320 if (nhc_l3mdev_matches_dev(nhc, dev)) {
321 dev_match = true;
322 break;
323 }
324 }
325 }
326 #else
327 if (fib_info_nhc(fi, 0)->nhc_dev == dev)
328 dev_match = true;
329 #endif
330
331 return dev_match;
332 }
333 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
334
335 /* Given (packet source, input interface) and optional (dst, oif, tos):
336 * - (main) check, that source is valid i.e. not broadcast or our local
337 * address.
338 * - figure out what "logical" interface this packet arrived
339 * and calculate "specific destination" address.
340 * - check, that packet arrived from expected physical interface.
341 * called with rcu_read_lock()
342 */
__fib_validate_source(struct sk_buff * skb,__be32 src,__be32 dst,u8 tos,int oif,struct net_device * dev,int rpf,struct in_device * idev,u32 * itag)343 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
344 u8 tos, int oif, struct net_device *dev,
345 int rpf, struct in_device *idev, u32 *itag)
346 {
347 struct net *net = dev_net(dev);
348 struct flow_keys flkeys;
349 int ret, no_addr;
350 struct fib_result res;
351 struct flowi4 fl4;
352 bool dev_match;
353
354 fl4.flowi4_oif = 0;
355 fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev);
356 if (!fl4.flowi4_iif)
357 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
358 fl4.daddr = src;
359 fl4.saddr = dst;
360 fl4.flowi4_tos = tos;
361 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
362 fl4.flowi4_tun_key.tun_id = 0;
363 fl4.flowi4_flags = 0;
364 fl4.flowi4_uid = sock_net_uid(net, NULL);
365 fl4.flowi4_multipath_hash = 0;
366
367 no_addr = idev->ifa_list == NULL;
368
369 fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
370 if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
371 fl4.flowi4_proto = 0;
372 fl4.fl4_sport = 0;
373 fl4.fl4_dport = 0;
374 } else {
375 swap(fl4.fl4_sport, fl4.fl4_dport);
376 }
377
378 if (fib_lookup(net, &fl4, &res, 0))
379 goto last_resort;
380 if (res.type != RTN_UNICAST &&
381 (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
382 goto e_inval;
383 fib_combine_itag(itag, &res);
384
385 dev_match = fib_info_nh_uses_dev(res.fi, dev);
386 /* This is not common, loopback packets retain skb_dst so normally they
387 * would not even hit this slow path.
388 */
389 dev_match = dev_match || (res.type == RTN_LOCAL &&
390 dev == net->loopback_dev);
391 if (dev_match) {
392 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_LINK;
393 return ret;
394 }
395 if (no_addr)
396 goto last_resort;
397 if (rpf == 1)
398 goto e_rpf;
399 fl4.flowi4_oif = dev->ifindex;
400
401 ret = 0;
402 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
403 if (res.type == RTN_UNICAST)
404 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_LINK;
405 }
406 return ret;
407
408 last_resort:
409 if (rpf)
410 goto e_rpf;
411 *itag = 0;
412 return 0;
413
414 e_inval:
415 return -EINVAL;
416 e_rpf:
417 return -EXDEV;
418 }
419
420 /* Ignore rp_filter for packets protected by IPsec. */
fib_validate_source(struct sk_buff * skb,__be32 src,__be32 dst,u8 tos,int oif,struct net_device * dev,struct in_device * idev,u32 * itag)421 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
422 u8 tos, int oif, struct net_device *dev,
423 struct in_device *idev, u32 *itag)
424 {
425 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
426 struct net *net = dev_net(dev);
427
428 if (!r && !fib_num_tclassid_users(net) &&
429 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
430 if (IN_DEV_ACCEPT_LOCAL(idev))
431 goto ok;
432 /* with custom local routes in place, checking local addresses
433 * only will be too optimistic, with custom rules, checking
434 * local addresses only can be too strict, e.g. due to vrf
435 */
436 if (net->ipv4.fib_has_custom_local_routes ||
437 fib4_has_custom_rules(net))
438 goto full_check;
439 if (inet_lookup_ifaddr_rcu(net, src))
440 return -EINVAL;
441
442 ok:
443 *itag = 0;
444 return 0;
445 }
446
447 full_check:
448 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
449 }
450
sk_extract_addr(struct sockaddr * addr)451 static inline __be32 sk_extract_addr(struct sockaddr *addr)
452 {
453 return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
454 }
455
put_rtax(struct nlattr * mx,int len,int type,u32 value)456 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
457 {
458 struct nlattr *nla;
459
460 nla = (struct nlattr *) ((char *) mx + len);
461 nla->nla_type = type;
462 nla->nla_len = nla_attr_size(4);
463 *(u32 *) nla_data(nla) = value;
464
465 return len + nla_total_size(4);
466 }
467
rtentry_to_fib_config(struct net * net,int cmd,struct rtentry * rt,struct fib_config * cfg)468 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
469 struct fib_config *cfg)
470 {
471 __be32 addr;
472 int plen;
473
474 memset(cfg, 0, sizeof(*cfg));
475 cfg->fc_nlinfo.nl_net = net;
476
477 if (rt->rt_dst.sa_family != AF_INET)
478 return -EAFNOSUPPORT;
479
480 /*
481 * Check mask for validity:
482 * a) it must be contiguous.
483 * b) destination must have all host bits clear.
484 * c) if application forgot to set correct family (AF_INET),
485 * reject request unless it is absolutely clear i.e.
486 * both family and mask are zero.
487 */
488 plen = 32;
489 addr = sk_extract_addr(&rt->rt_dst);
490 if (!(rt->rt_flags & RTF_HOST)) {
491 __be32 mask = sk_extract_addr(&rt->rt_genmask);
492
493 if (rt->rt_genmask.sa_family != AF_INET) {
494 if (mask || rt->rt_genmask.sa_family)
495 return -EAFNOSUPPORT;
496 }
497
498 if (bad_mask(mask, addr))
499 return -EINVAL;
500
501 plen = inet_mask_len(mask);
502 }
503
504 cfg->fc_dst_len = plen;
505 cfg->fc_dst = addr;
506
507 if (cmd != SIOCDELRT) {
508 cfg->fc_nlflags = NLM_F_CREATE;
509 cfg->fc_protocol = RTPROT_BOOT;
510 }
511
512 if (rt->rt_metric)
513 cfg->fc_priority = rt->rt_metric - 1;
514
515 if (rt->rt_flags & RTF_REJECT) {
516 cfg->fc_scope = RT_SCOPE_HOST;
517 cfg->fc_type = RTN_UNREACHABLE;
518 return 0;
519 }
520
521 cfg->fc_scope = RT_SCOPE_NOWHERE;
522 cfg->fc_type = RTN_UNICAST;
523
524 if (rt->rt_dev) {
525 char *colon;
526 struct net_device *dev;
527 char devname[IFNAMSIZ];
528
529 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
530 return -EFAULT;
531
532 devname[IFNAMSIZ-1] = 0;
533 colon = strchr(devname, ':');
534 if (colon)
535 *colon = 0;
536 dev = __dev_get_by_name(net, devname);
537 if (!dev)
538 return -ENODEV;
539 cfg->fc_oif = dev->ifindex;
540 cfg->fc_table = l3mdev_fib_table(dev);
541 if (colon) {
542 const struct in_ifaddr *ifa;
543 struct in_device *in_dev;
544
545 in_dev = __in_dev_get_rtnl(dev);
546 if (!in_dev)
547 return -ENODEV;
548
549 *colon = ':';
550
551 rcu_read_lock();
552 in_dev_for_each_ifa_rcu(ifa, in_dev) {
553 if (strcmp(ifa->ifa_label, devname) == 0)
554 break;
555 }
556 rcu_read_unlock();
557
558 if (!ifa)
559 return -ENODEV;
560 cfg->fc_prefsrc = ifa->ifa_local;
561 }
562 }
563
564 addr = sk_extract_addr(&rt->rt_gateway);
565 if (rt->rt_gateway.sa_family == AF_INET && addr) {
566 unsigned int addr_type;
567
568 cfg->fc_gw4 = addr;
569 cfg->fc_gw_family = AF_INET;
570 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
571 if (rt->rt_flags & RTF_GATEWAY &&
572 addr_type == RTN_UNICAST)
573 cfg->fc_scope = RT_SCOPE_UNIVERSE;
574 }
575
576 if (!cfg->fc_table)
577 cfg->fc_table = RT_TABLE_MAIN;
578
579 if (cmd == SIOCDELRT)
580 return 0;
581
582 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
583 return -EINVAL;
584
585 if (cfg->fc_scope == RT_SCOPE_NOWHERE)
586 cfg->fc_scope = RT_SCOPE_LINK;
587
588 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
589 struct nlattr *mx;
590 int len = 0;
591
592 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
593 if (!mx)
594 return -ENOMEM;
595
596 if (rt->rt_flags & RTF_MTU)
597 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
598
599 if (rt->rt_flags & RTF_WINDOW)
600 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
601
602 if (rt->rt_flags & RTF_IRTT)
603 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
604
605 cfg->fc_mx = mx;
606 cfg->fc_mx_len = len;
607 }
608
609 return 0;
610 }
611
612 /*
613 * Handle IP routing ioctl calls.
614 * These are used to manipulate the routing tables
615 */
ip_rt_ioctl(struct net * net,unsigned int cmd,struct rtentry * rt)616 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
617 {
618 struct fib_config cfg;
619 int err;
620
621 switch (cmd) {
622 case SIOCADDRT: /* Add a route */
623 case SIOCDELRT: /* Delete a route */
624 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
625 return -EPERM;
626
627 rtnl_lock();
628 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
629 if (err == 0) {
630 struct fib_table *tb;
631
632 if (cmd == SIOCDELRT) {
633 tb = fib_get_table(net, cfg.fc_table);
634 if (tb)
635 err = fib_table_delete(net, tb, &cfg,
636 NULL);
637 else
638 err = -ESRCH;
639 } else {
640 tb = fib_new_table(net, cfg.fc_table);
641 if (tb)
642 err = fib_table_insert(net, tb,
643 &cfg, NULL);
644 else
645 err = -ENOBUFS;
646 }
647
648 /* allocated by rtentry_to_fib_config() */
649 kfree(cfg.fc_mx);
650 }
651 rtnl_unlock();
652 return err;
653 }
654 return -EINVAL;
655 }
656
657 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
658 [RTA_UNSPEC] = { .strict_start_type = RTA_DPORT + 1 },
659 [RTA_DST] = { .type = NLA_U32 },
660 [RTA_SRC] = { .type = NLA_U32 },
661 [RTA_IIF] = { .type = NLA_U32 },
662 [RTA_OIF] = { .type = NLA_U32 },
663 [RTA_GATEWAY] = { .type = NLA_U32 },
664 [RTA_PRIORITY] = { .type = NLA_U32 },
665 [RTA_PREFSRC] = { .type = NLA_U32 },
666 [RTA_METRICS] = { .type = NLA_NESTED },
667 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
668 [RTA_FLOW] = { .type = NLA_U32 },
669 [RTA_ENCAP_TYPE] = { .type = NLA_U16 },
670 [RTA_ENCAP] = { .type = NLA_NESTED },
671 [RTA_UID] = { .type = NLA_U32 },
672 [RTA_MARK] = { .type = NLA_U32 },
673 [RTA_TABLE] = { .type = NLA_U32 },
674 [RTA_IP_PROTO] = { .type = NLA_U8 },
675 [RTA_SPORT] = { .type = NLA_U16 },
676 [RTA_DPORT] = { .type = NLA_U16 },
677 [RTA_NH_ID] = { .type = NLA_U32 },
678 };
679
fib_gw_from_via(struct fib_config * cfg,struct nlattr * nla,struct netlink_ext_ack * extack)680 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
681 struct netlink_ext_ack *extack)
682 {
683 struct rtvia *via;
684 int alen;
685
686 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
687 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
688 return -EINVAL;
689 }
690
691 via = nla_data(nla);
692 alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
693
694 switch (via->rtvia_family) {
695 case AF_INET:
696 if (alen != sizeof(__be32)) {
697 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
698 return -EINVAL;
699 }
700 cfg->fc_gw_family = AF_INET;
701 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
702 break;
703 case AF_INET6:
704 #if IS_ENABLED(CONFIG_IPV6)
705 if (alen != sizeof(struct in6_addr)) {
706 NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
707 return -EINVAL;
708 }
709 cfg->fc_gw_family = AF_INET6;
710 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
711 #else
712 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
713 return -EINVAL;
714 #endif
715 break;
716 default:
717 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
718 return -EINVAL;
719 }
720
721 return 0;
722 }
723
rtm_to_fib_config(struct net * net,struct sk_buff * skb,struct nlmsghdr * nlh,struct fib_config * cfg,struct netlink_ext_ack * extack)724 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
725 struct nlmsghdr *nlh, struct fib_config *cfg,
726 struct netlink_ext_ack *extack)
727 {
728 bool has_gw = false, has_via = false;
729 struct nlattr *attr;
730 int err, remaining;
731 struct rtmsg *rtm;
732
733 err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
734 rtm_ipv4_policy, extack);
735 if (err < 0)
736 goto errout;
737
738 memset(cfg, 0, sizeof(*cfg));
739
740 rtm = nlmsg_data(nlh);
741 cfg->fc_dst_len = rtm->rtm_dst_len;
742 cfg->fc_tos = rtm->rtm_tos;
743 cfg->fc_table = rtm->rtm_table;
744 cfg->fc_protocol = rtm->rtm_protocol;
745 cfg->fc_scope = rtm->rtm_scope;
746 cfg->fc_type = rtm->rtm_type;
747 cfg->fc_flags = rtm->rtm_flags;
748 cfg->fc_nlflags = nlh->nlmsg_flags;
749
750 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
751 cfg->fc_nlinfo.nlh = nlh;
752 cfg->fc_nlinfo.nl_net = net;
753
754 if (cfg->fc_type > RTN_MAX) {
755 NL_SET_ERR_MSG(extack, "Invalid route type");
756 err = -EINVAL;
757 goto errout;
758 }
759
760 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
761 switch (nla_type(attr)) {
762 case RTA_DST:
763 cfg->fc_dst = nla_get_be32(attr);
764 break;
765 case RTA_OIF:
766 cfg->fc_oif = nla_get_u32(attr);
767 break;
768 case RTA_GATEWAY:
769 has_gw = true;
770 cfg->fc_gw4 = nla_get_be32(attr);
771 if (cfg->fc_gw4)
772 cfg->fc_gw_family = AF_INET;
773 break;
774 case RTA_VIA:
775 has_via = true;
776 err = fib_gw_from_via(cfg, attr, extack);
777 if (err)
778 goto errout;
779 break;
780 case RTA_PRIORITY:
781 cfg->fc_priority = nla_get_u32(attr);
782 break;
783 case RTA_PREFSRC:
784 cfg->fc_prefsrc = nla_get_be32(attr);
785 break;
786 case RTA_METRICS:
787 cfg->fc_mx = nla_data(attr);
788 cfg->fc_mx_len = nla_len(attr);
789 break;
790 case RTA_MULTIPATH:
791 err = lwtunnel_valid_encap_type_attr(nla_data(attr),
792 nla_len(attr),
793 extack);
794 if (err < 0)
795 goto errout;
796 cfg->fc_mp = nla_data(attr);
797 cfg->fc_mp_len = nla_len(attr);
798 break;
799 case RTA_FLOW:
800 cfg->fc_flow = nla_get_u32(attr);
801 break;
802 case RTA_TABLE:
803 cfg->fc_table = nla_get_u32(attr);
804 break;
805 case RTA_ENCAP:
806 cfg->fc_encap = attr;
807 break;
808 case RTA_ENCAP_TYPE:
809 cfg->fc_encap_type = nla_get_u16(attr);
810 err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
811 extack);
812 if (err < 0)
813 goto errout;
814 break;
815 case RTA_NH_ID:
816 cfg->fc_nh_id = nla_get_u32(attr);
817 break;
818 }
819 }
820
821 if (cfg->fc_nh_id) {
822 if (cfg->fc_oif || cfg->fc_gw_family ||
823 cfg->fc_encap || cfg->fc_mp) {
824 NL_SET_ERR_MSG(extack,
825 "Nexthop specification and nexthop id are mutually exclusive");
826 return -EINVAL;
827 }
828 }
829
830 if (has_gw && has_via) {
831 NL_SET_ERR_MSG(extack,
832 "Nexthop configuration can not contain both GATEWAY and VIA");
833 return -EINVAL;
834 }
835
836 if (!cfg->fc_table)
837 cfg->fc_table = RT_TABLE_MAIN;
838
839 return 0;
840 errout:
841 return err;
842 }
843
inet_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)844 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
845 struct netlink_ext_ack *extack)
846 {
847 struct net *net = sock_net(skb->sk);
848 struct fib_config cfg;
849 struct fib_table *tb;
850 int err;
851
852 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
853 if (err < 0)
854 goto errout;
855
856 if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
857 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
858 err = -EINVAL;
859 goto errout;
860 }
861
862 tb = fib_get_table(net, cfg.fc_table);
863 if (!tb) {
864 NL_SET_ERR_MSG(extack, "FIB table does not exist");
865 err = -ESRCH;
866 goto errout;
867 }
868
869 err = fib_table_delete(net, tb, &cfg, extack);
870 errout:
871 return err;
872 }
873
inet_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)874 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
875 struct netlink_ext_ack *extack)
876 {
877 struct net *net = sock_net(skb->sk);
878 struct fib_config cfg;
879 struct fib_table *tb;
880 int err;
881
882 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
883 if (err < 0)
884 goto errout;
885
886 tb = fib_new_table(net, cfg.fc_table);
887 if (!tb) {
888 err = -ENOBUFS;
889 goto errout;
890 }
891
892 err = fib_table_insert(net, tb, &cfg, extack);
893 if (!err && cfg.fc_type == RTN_LOCAL)
894 net->ipv4.fib_has_custom_local_routes = true;
895 errout:
896 return err;
897 }
898
ip_valid_fib_dump_req(struct net * net,const struct nlmsghdr * nlh,struct fib_dump_filter * filter,struct netlink_callback * cb)899 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
900 struct fib_dump_filter *filter,
901 struct netlink_callback *cb)
902 {
903 struct netlink_ext_ack *extack = cb->extack;
904 struct nlattr *tb[RTA_MAX + 1];
905 struct rtmsg *rtm;
906 int err, i;
907
908 ASSERT_RTNL();
909
910 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
911 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
912 return -EINVAL;
913 }
914
915 rtm = nlmsg_data(nlh);
916 if (rtm->rtm_dst_len || rtm->rtm_src_len || rtm->rtm_tos ||
917 rtm->rtm_scope) {
918 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
919 return -EINVAL;
920 }
921
922 if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
923 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
924 return -EINVAL;
925 }
926 if (rtm->rtm_flags & RTM_F_CLONED)
927 filter->dump_routes = false;
928 else
929 filter->dump_exceptions = false;
930
931 filter->flags = rtm->rtm_flags;
932 filter->protocol = rtm->rtm_protocol;
933 filter->rt_type = rtm->rtm_type;
934 filter->table_id = rtm->rtm_table;
935
936 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
937 rtm_ipv4_policy, extack);
938 if (err < 0)
939 return err;
940
941 for (i = 0; i <= RTA_MAX; ++i) {
942 int ifindex;
943
944 if (!tb[i])
945 continue;
946
947 switch (i) {
948 case RTA_TABLE:
949 filter->table_id = nla_get_u32(tb[i]);
950 break;
951 case RTA_OIF:
952 ifindex = nla_get_u32(tb[i]);
953 filter->dev = __dev_get_by_index(net, ifindex);
954 if (!filter->dev)
955 return -ENODEV;
956 break;
957 default:
958 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
959 return -EINVAL;
960 }
961 }
962
963 if (filter->flags || filter->protocol || filter->rt_type ||
964 filter->table_id || filter->dev) {
965 filter->filter_set = 1;
966 cb->answer_flags = NLM_F_DUMP_FILTERED;
967 }
968
969 return 0;
970 }
971 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
972
inet_dump_fib(struct sk_buff * skb,struct netlink_callback * cb)973 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
974 {
975 struct fib_dump_filter filter = { .dump_routes = true,
976 .dump_exceptions = true };
977 const struct nlmsghdr *nlh = cb->nlh;
978 struct net *net = sock_net(skb->sk);
979 unsigned int h, s_h;
980 unsigned int e = 0, s_e;
981 struct fib_table *tb;
982 struct hlist_head *head;
983 int dumped = 0, err;
984
985 if (cb->strict_check) {
986 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
987 if (err < 0)
988 return err;
989 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
990 struct rtmsg *rtm = nlmsg_data(nlh);
991
992 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
993 }
994
995 /* ipv4 does not use prefix flag */
996 if (filter.flags & RTM_F_PREFIX)
997 return skb->len;
998
999 if (filter.table_id) {
1000 tb = fib_get_table(net, filter.table_id);
1001 if (!tb) {
1002 if (rtnl_msg_family(cb->nlh) != PF_INET)
1003 return skb->len;
1004
1005 NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1006 return -ENOENT;
1007 }
1008
1009 rcu_read_lock();
1010 err = fib_table_dump(tb, skb, cb, &filter);
1011 rcu_read_unlock();
1012 return skb->len ? : err;
1013 }
1014
1015 s_h = cb->args[0];
1016 s_e = cb->args[1];
1017
1018 rcu_read_lock();
1019
1020 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1021 e = 0;
1022 head = &net->ipv4.fib_table_hash[h];
1023 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1024 if (e < s_e)
1025 goto next;
1026 if (dumped)
1027 memset(&cb->args[2], 0, sizeof(cb->args) -
1028 2 * sizeof(cb->args[0]));
1029 err = fib_table_dump(tb, skb, cb, &filter);
1030 if (err < 0) {
1031 if (likely(skb->len))
1032 goto out;
1033
1034 goto out_err;
1035 }
1036 dumped = 1;
1037 next:
1038 e++;
1039 }
1040 }
1041 out:
1042 err = skb->len;
1043 out_err:
1044 rcu_read_unlock();
1045
1046 cb->args[1] = e;
1047 cb->args[0] = h;
1048
1049 return err;
1050 }
1051
1052 /* Prepare and feed intra-kernel routing request.
1053 * Really, it should be netlink message, but :-( netlink
1054 * can be not configured, so that we feed it directly
1055 * to fib engine. It is legal, because all events occur
1056 * only when netlink is already locked.
1057 */
fib_magic(int cmd,int type,__be32 dst,int dst_len,struct in_ifaddr * ifa,u32 rt_priority)1058 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1059 struct in_ifaddr *ifa, u32 rt_priority)
1060 {
1061 struct net *net = dev_net(ifa->ifa_dev->dev);
1062 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1063 struct fib_table *tb;
1064 struct fib_config cfg = {
1065 .fc_protocol = RTPROT_KERNEL,
1066 .fc_type = type,
1067 .fc_dst = dst,
1068 .fc_dst_len = dst_len,
1069 .fc_priority = rt_priority,
1070 .fc_prefsrc = ifa->ifa_local,
1071 .fc_oif = ifa->ifa_dev->dev->ifindex,
1072 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1073 .fc_nlinfo = {
1074 .nl_net = net,
1075 },
1076 };
1077
1078 if (!tb_id)
1079 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1080
1081 tb = fib_new_table(net, tb_id);
1082 if (!tb)
1083 return;
1084
1085 cfg.fc_table = tb->tb_id;
1086
1087 if (type != RTN_LOCAL)
1088 cfg.fc_scope = RT_SCOPE_LINK;
1089 else
1090 cfg.fc_scope = RT_SCOPE_HOST;
1091
1092 if (cmd == RTM_NEWROUTE)
1093 fib_table_insert(net, tb, &cfg, NULL);
1094 else
1095 fib_table_delete(net, tb, &cfg, NULL);
1096 }
1097
fib_add_ifaddr(struct in_ifaddr * ifa)1098 void fib_add_ifaddr(struct in_ifaddr *ifa)
1099 {
1100 struct in_device *in_dev = ifa->ifa_dev;
1101 struct net_device *dev = in_dev->dev;
1102 struct in_ifaddr *prim = ifa;
1103 __be32 mask = ifa->ifa_mask;
1104 __be32 addr = ifa->ifa_local;
1105 __be32 prefix = ifa->ifa_address & mask;
1106
1107 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1108 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1109 if (!prim) {
1110 pr_warn("%s: bug: prim == NULL\n", __func__);
1111 return;
1112 }
1113 }
1114
1115 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1116
1117 if (!(dev->flags & IFF_UP))
1118 return;
1119
1120 /* Add broadcast address, if it is explicitly assigned. */
1121 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) {
1122 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1123 prim, 0);
1124 arp_invalidate(dev, ifa->ifa_broadcast, false);
1125 }
1126
1127 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1128 (prefix != addr || ifa->ifa_prefixlen < 32)) {
1129 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1130 fib_magic(RTM_NEWROUTE,
1131 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1132 prefix, ifa->ifa_prefixlen, prim,
1133 ifa->ifa_rt_priority);
1134
1135 /* Add network specific broadcasts, when it takes a sense */
1136 if (ifa->ifa_prefixlen < 31) {
1137 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32,
1138 prim, 0);
1139 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1140 32, prim, 0);
1141 arp_invalidate(dev, prefix | ~mask, false);
1142 }
1143 }
1144 }
1145
fib_modify_prefix_metric(struct in_ifaddr * ifa,u32 new_metric)1146 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1147 {
1148 __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1149 struct in_device *in_dev = ifa->ifa_dev;
1150 struct net_device *dev = in_dev->dev;
1151
1152 if (!(dev->flags & IFF_UP) ||
1153 ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1154 ipv4_is_zeronet(prefix) ||
1155 (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1156 return;
1157
1158 /* add the new */
1159 fib_magic(RTM_NEWROUTE,
1160 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1161 prefix, ifa->ifa_prefixlen, ifa, new_metric);
1162
1163 /* delete the old */
1164 fib_magic(RTM_DELROUTE,
1165 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1166 prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1167 }
1168
1169 /* Delete primary or secondary address.
1170 * Optionally, on secondary address promotion consider the addresses
1171 * from subnet iprim as deleted, even if they are in device list.
1172 * In this case the secondary ifa can be in device list.
1173 */
fib_del_ifaddr(struct in_ifaddr * ifa,struct in_ifaddr * iprim)1174 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1175 {
1176 struct in_device *in_dev = ifa->ifa_dev;
1177 struct net_device *dev = in_dev->dev;
1178 struct in_ifaddr *ifa1;
1179 struct in_ifaddr *prim = ifa, *prim1 = NULL;
1180 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1181 __be32 any = ifa->ifa_address & ifa->ifa_mask;
1182 #define LOCAL_OK 1
1183 #define BRD_OK 2
1184 #define BRD0_OK 4
1185 #define BRD1_OK 8
1186 unsigned int ok = 0;
1187 int subnet = 0; /* Primary network */
1188 int gone = 1; /* Address is missing */
1189 int same_prefsrc = 0; /* Another primary with same IP */
1190
1191 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1192 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1193 if (!prim) {
1194 /* if the device has been deleted, we don't perform
1195 * address promotion
1196 */
1197 if (!in_dev->dead)
1198 pr_warn("%s: bug: prim == NULL\n", __func__);
1199 return;
1200 }
1201 if (iprim && iprim != prim) {
1202 pr_warn("%s: bug: iprim != prim\n", __func__);
1203 return;
1204 }
1205 } else if (!ipv4_is_zeronet(any) &&
1206 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1207 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1208 fib_magic(RTM_DELROUTE,
1209 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1210 any, ifa->ifa_prefixlen, prim, 0);
1211 subnet = 1;
1212 }
1213
1214 if (in_dev->dead)
1215 goto no_promotions;
1216
1217 /* Deletion is more complicated than add.
1218 * We should take care of not to delete too much :-)
1219 *
1220 * Scan address list to be sure that addresses are really gone.
1221 */
1222 rcu_read_lock();
1223 in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1224 if (ifa1 == ifa) {
1225 /* promotion, keep the IP */
1226 gone = 0;
1227 continue;
1228 }
1229 /* Ignore IFAs from our subnet */
1230 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1231 inet_ifa_match(ifa1->ifa_address, iprim))
1232 continue;
1233
1234 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1235 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1236 /* Another address from our subnet? */
1237 if (ifa1->ifa_mask == prim->ifa_mask &&
1238 inet_ifa_match(ifa1->ifa_address, prim))
1239 prim1 = prim;
1240 else {
1241 /* We reached the secondaries, so
1242 * same_prefsrc should be determined.
1243 */
1244 if (!same_prefsrc)
1245 continue;
1246 /* Search new prim1 if ifa1 is not
1247 * using the current prim1
1248 */
1249 if (!prim1 ||
1250 ifa1->ifa_mask != prim1->ifa_mask ||
1251 !inet_ifa_match(ifa1->ifa_address, prim1))
1252 prim1 = inet_ifa_byprefix(in_dev,
1253 ifa1->ifa_address,
1254 ifa1->ifa_mask);
1255 if (!prim1)
1256 continue;
1257 if (prim1->ifa_local != prim->ifa_local)
1258 continue;
1259 }
1260 } else {
1261 if (prim->ifa_local != ifa1->ifa_local)
1262 continue;
1263 prim1 = ifa1;
1264 if (prim != prim1)
1265 same_prefsrc = 1;
1266 }
1267 if (ifa->ifa_local == ifa1->ifa_local)
1268 ok |= LOCAL_OK;
1269 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1270 ok |= BRD_OK;
1271 if (brd == ifa1->ifa_broadcast)
1272 ok |= BRD1_OK;
1273 if (any == ifa1->ifa_broadcast)
1274 ok |= BRD0_OK;
1275 /* primary has network specific broadcasts */
1276 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1277 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1278 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1279
1280 if (!ipv4_is_zeronet(any1)) {
1281 if (ifa->ifa_broadcast == brd1 ||
1282 ifa->ifa_broadcast == any1)
1283 ok |= BRD_OK;
1284 if (brd == brd1 || brd == any1)
1285 ok |= BRD1_OK;
1286 if (any == brd1 || any == any1)
1287 ok |= BRD0_OK;
1288 }
1289 }
1290 }
1291 rcu_read_unlock();
1292
1293 no_promotions:
1294 if (!(ok & BRD_OK))
1295 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1296 prim, 0);
1297 if (subnet && ifa->ifa_prefixlen < 31) {
1298 if (!(ok & BRD1_OK))
1299 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1300 prim, 0);
1301 if (!(ok & BRD0_OK))
1302 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1303 prim, 0);
1304 }
1305 if (!(ok & LOCAL_OK)) {
1306 unsigned int addr_type;
1307
1308 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1309
1310 /* Check, that this local address finally disappeared. */
1311 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1312 ifa->ifa_local);
1313 if (gone && addr_type != RTN_LOCAL) {
1314 /* And the last, but not the least thing.
1315 * We must flush stray FIB entries.
1316 *
1317 * First of all, we scan fib_info list searching
1318 * for stray nexthop entries, then ignite fib_flush.
1319 */
1320 if (fib_sync_down_addr(dev, ifa->ifa_local))
1321 fib_flush(dev_net(dev));
1322 }
1323 }
1324 #undef LOCAL_OK
1325 #undef BRD_OK
1326 #undef BRD0_OK
1327 #undef BRD1_OK
1328 }
1329
nl_fib_lookup(struct net * net,struct fib_result_nl * frn)1330 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1331 {
1332
1333 struct fib_result res;
1334 struct flowi4 fl4 = {
1335 .flowi4_mark = frn->fl_mark,
1336 .daddr = frn->fl_addr,
1337 .flowi4_tos = frn->fl_tos,
1338 .flowi4_scope = frn->fl_scope,
1339 };
1340 struct fib_table *tb;
1341
1342 rcu_read_lock();
1343
1344 tb = fib_get_table(net, frn->tb_id_in);
1345
1346 frn->err = -ENOENT;
1347 if (tb) {
1348 local_bh_disable();
1349
1350 frn->tb_id = tb->tb_id;
1351 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1352
1353 if (!frn->err) {
1354 frn->prefixlen = res.prefixlen;
1355 frn->nh_sel = res.nh_sel;
1356 frn->type = res.type;
1357 frn->scope = res.scope;
1358 }
1359 local_bh_enable();
1360 }
1361
1362 rcu_read_unlock();
1363 }
1364
nl_fib_input(struct sk_buff * skb)1365 static void nl_fib_input(struct sk_buff *skb)
1366 {
1367 struct net *net;
1368 struct fib_result_nl *frn;
1369 struct nlmsghdr *nlh;
1370 u32 portid;
1371
1372 net = sock_net(skb->sk);
1373 nlh = nlmsg_hdr(skb);
1374 if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1375 skb->len < nlh->nlmsg_len ||
1376 nlmsg_len(nlh) < sizeof(*frn))
1377 return;
1378
1379 skb = netlink_skb_clone(skb, GFP_KERNEL);
1380 if (!skb)
1381 return;
1382 nlh = nlmsg_hdr(skb);
1383
1384 frn = (struct fib_result_nl *) nlmsg_data(nlh);
1385 nl_fib_lookup(net, frn);
1386
1387 portid = NETLINK_CB(skb).portid; /* netlink portid */
1388 NETLINK_CB(skb).portid = 0; /* from kernel */
1389 NETLINK_CB(skb).dst_group = 0; /* unicast */
1390 netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
1391 }
1392
nl_fib_lookup_init(struct net * net)1393 static int __net_init nl_fib_lookup_init(struct net *net)
1394 {
1395 struct sock *sk;
1396 struct netlink_kernel_cfg cfg = {
1397 .input = nl_fib_input,
1398 };
1399
1400 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1401 if (!sk)
1402 return -EAFNOSUPPORT;
1403 net->ipv4.fibnl = sk;
1404 return 0;
1405 }
1406
nl_fib_lookup_exit(struct net * net)1407 static void nl_fib_lookup_exit(struct net *net)
1408 {
1409 netlink_kernel_release(net->ipv4.fibnl);
1410 net->ipv4.fibnl = NULL;
1411 }
1412
fib_disable_ip(struct net_device * dev,unsigned long event,bool force)1413 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1414 bool force)
1415 {
1416 if (fib_sync_down_dev(dev, event, force))
1417 fib_flush(dev_net(dev));
1418 else
1419 rt_cache_flush(dev_net(dev));
1420 arp_ifdown(dev);
1421 }
1422
fib_inetaddr_event(struct notifier_block * this,unsigned long event,void * ptr)1423 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1424 {
1425 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1426 struct net_device *dev = ifa->ifa_dev->dev;
1427 struct net *net = dev_net(dev);
1428
1429 switch (event) {
1430 case NETDEV_UP:
1431 fib_add_ifaddr(ifa);
1432 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1433 fib_sync_up(dev, RTNH_F_DEAD);
1434 #endif
1435 atomic_inc(&net->ipv4.dev_addr_genid);
1436 rt_cache_flush(dev_net(dev));
1437 break;
1438 case NETDEV_DOWN:
1439 fib_del_ifaddr(ifa, NULL);
1440 atomic_inc(&net->ipv4.dev_addr_genid);
1441 if (!ifa->ifa_dev->ifa_list) {
1442 /* Last address was deleted from this interface.
1443 * Disable IP.
1444 */
1445 fib_disable_ip(dev, event, true);
1446 } else {
1447 rt_cache_flush(dev_net(dev));
1448 }
1449 break;
1450 }
1451 return NOTIFY_DONE;
1452 }
1453
fib_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1454 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1455 {
1456 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1457 struct netdev_notifier_changeupper_info *upper_info = ptr;
1458 struct netdev_notifier_info_ext *info_ext = ptr;
1459 struct in_device *in_dev;
1460 struct net *net = dev_net(dev);
1461 struct in_ifaddr *ifa;
1462 unsigned int flags;
1463
1464 if (event == NETDEV_UNREGISTER) {
1465 fib_disable_ip(dev, event, true);
1466 rt_flush_dev(dev);
1467 return NOTIFY_DONE;
1468 }
1469
1470 in_dev = __in_dev_get_rtnl(dev);
1471 if (!in_dev)
1472 return NOTIFY_DONE;
1473
1474 switch (event) {
1475 case NETDEV_UP:
1476 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1477 fib_add_ifaddr(ifa);
1478 }
1479 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1480 fib_sync_up(dev, RTNH_F_DEAD);
1481 #endif
1482 atomic_inc(&net->ipv4.dev_addr_genid);
1483 rt_cache_flush(net);
1484 break;
1485 case NETDEV_DOWN:
1486 fib_disable_ip(dev, event, false);
1487 break;
1488 case NETDEV_CHANGE:
1489 flags = dev_get_flags(dev);
1490 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1491 fib_sync_up(dev, RTNH_F_LINKDOWN);
1492 else
1493 fib_sync_down_dev(dev, event, false);
1494 rt_cache_flush(net);
1495 break;
1496 case NETDEV_CHANGEMTU:
1497 fib_sync_mtu(dev, info_ext->ext.mtu);
1498 rt_cache_flush(net);
1499 break;
1500 case NETDEV_CHANGEUPPER:
1501 upper_info = ptr;
1502 /* flush all routes if dev is linked to or unlinked from
1503 * an L3 master device (e.g., VRF)
1504 */
1505 if (upper_info->upper_dev &&
1506 netif_is_l3_master(upper_info->upper_dev))
1507 fib_disable_ip(dev, NETDEV_DOWN, true);
1508 break;
1509 }
1510 return NOTIFY_DONE;
1511 }
1512
1513 static struct notifier_block fib_inetaddr_notifier = {
1514 .notifier_call = fib_inetaddr_event,
1515 };
1516
1517 static struct notifier_block fib_netdev_notifier = {
1518 .notifier_call = fib_netdev_event,
1519 };
1520
ip_fib_net_init(struct net * net)1521 static int __net_init ip_fib_net_init(struct net *net)
1522 {
1523 int err;
1524 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1525
1526 err = fib4_notifier_init(net);
1527 if (err)
1528 return err;
1529
1530 /* Avoid false sharing : Use at least a full cache line */
1531 size = max_t(size_t, size, L1_CACHE_BYTES);
1532
1533 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1534 if (!net->ipv4.fib_table_hash) {
1535 err = -ENOMEM;
1536 goto err_table_hash_alloc;
1537 }
1538
1539 err = fib4_rules_init(net);
1540 if (err < 0)
1541 goto err_rules_init;
1542 return 0;
1543
1544 err_rules_init:
1545 kfree(net->ipv4.fib_table_hash);
1546 err_table_hash_alloc:
1547 fib4_notifier_exit(net);
1548 return err;
1549 }
1550
ip_fib_net_exit(struct net * net)1551 static void ip_fib_net_exit(struct net *net)
1552 {
1553 int i;
1554
1555 rtnl_lock();
1556 #ifdef CONFIG_IP_MULTIPLE_TABLES
1557 RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1558 RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1559 #endif
1560 /* Destroy the tables in reverse order to guarantee that the
1561 * local table, ID 255, is destroyed before the main table, ID
1562 * 254. This is necessary as the local table may contain
1563 * references to data contained in the main table.
1564 */
1565 for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1566 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1567 struct hlist_node *tmp;
1568 struct fib_table *tb;
1569
1570 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1571 hlist_del(&tb->tb_hlist);
1572 fib_table_flush(net, tb, true);
1573 fib_free_table(tb);
1574 }
1575 }
1576
1577 #ifdef CONFIG_IP_MULTIPLE_TABLES
1578 fib4_rules_exit(net);
1579 #endif
1580 rtnl_unlock();
1581 kfree(net->ipv4.fib_table_hash);
1582 fib4_notifier_exit(net);
1583 }
1584
fib_net_init(struct net * net)1585 static int __net_init fib_net_init(struct net *net)
1586 {
1587 int error;
1588
1589 #ifdef CONFIG_IP_ROUTE_CLASSID
1590 atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
1591 #endif
1592 error = ip_fib_net_init(net);
1593 if (error < 0)
1594 goto out;
1595 error = nl_fib_lookup_init(net);
1596 if (error < 0)
1597 goto out_nlfl;
1598 error = fib_proc_init(net);
1599 if (error < 0)
1600 goto out_proc;
1601 out:
1602 return error;
1603
1604 out_proc:
1605 nl_fib_lookup_exit(net);
1606 out_nlfl:
1607 ip_fib_net_exit(net);
1608 goto out;
1609 }
1610
fib_net_exit(struct net * net)1611 static void __net_exit fib_net_exit(struct net *net)
1612 {
1613 fib_proc_exit(net);
1614 nl_fib_lookup_exit(net);
1615 ip_fib_net_exit(net);
1616 }
1617
1618 static struct pernet_operations fib_net_ops = {
1619 .init = fib_net_init,
1620 .exit = fib_net_exit,
1621 };
1622
ip_fib_init(void)1623 void __init ip_fib_init(void)
1624 {
1625 fib_trie_init();
1626
1627 register_pernet_subsys(&fib_net_ops);
1628
1629 register_netdevice_notifier(&fib_netdev_notifier);
1630 register_inetaddr_notifier(&fib_inetaddr_notifier);
1631
1632 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1633 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1634 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1635 }
1636