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 = RT_TOS(ip_hdr(skb)->tos),
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 }
375
376 if (fib_lookup(net, &fl4, &res, 0))
377 goto last_resort;
378 if (res.type != RTN_UNICAST &&
379 (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
380 goto e_inval;
381 fib_combine_itag(itag, &res);
382
383 dev_match = fib_info_nh_uses_dev(res.fi, dev);
384 /* This is not common, loopback packets retain skb_dst so normally they
385 * would not even hit this slow path.
386 */
387 dev_match = dev_match || (res.type == RTN_LOCAL &&
388 dev == net->loopback_dev);
389 if (dev_match) {
390 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
391 return ret;
392 }
393 if (no_addr)
394 goto last_resort;
395 if (rpf == 1)
396 goto e_rpf;
397 fl4.flowi4_oif = dev->ifindex;
398
399 ret = 0;
400 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
401 if (res.type == RTN_UNICAST)
402 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
403 }
404 return ret;
405
406 last_resort:
407 if (rpf)
408 goto e_rpf;
409 *itag = 0;
410 return 0;
411
412 e_inval:
413 return -EINVAL;
414 e_rpf:
415 return -EXDEV;
416 }
417
418 /* 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)419 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
420 u8 tos, int oif, struct net_device *dev,
421 struct in_device *idev, u32 *itag)
422 {
423 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
424 struct net *net = dev_net(dev);
425
426 if (!r && !fib_num_tclassid_users(net) &&
427 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
428 if (IN_DEV_ACCEPT_LOCAL(idev))
429 goto ok;
430 /* with custom local routes in place, checking local addresses
431 * only will be too optimistic, with custom rules, checking
432 * local addresses only can be too strict, e.g. due to vrf
433 */
434 if (net->ipv4.fib_has_custom_local_routes ||
435 fib4_has_custom_rules(net))
436 goto full_check;
437 if (inet_lookup_ifaddr_rcu(net, src))
438 return -EINVAL;
439
440 ok:
441 *itag = 0;
442 return 0;
443 }
444
445 full_check:
446 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
447 }
448
sk_extract_addr(struct sockaddr * addr)449 static inline __be32 sk_extract_addr(struct sockaddr *addr)
450 {
451 return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
452 }
453
put_rtax(struct nlattr * mx,int len,int type,u32 value)454 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
455 {
456 struct nlattr *nla;
457
458 nla = (struct nlattr *) ((char *) mx + len);
459 nla->nla_type = type;
460 nla->nla_len = nla_attr_size(4);
461 *(u32 *) nla_data(nla) = value;
462
463 return len + nla_total_size(4);
464 }
465
rtentry_to_fib_config(struct net * net,int cmd,struct rtentry * rt,struct fib_config * cfg)466 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
467 struct fib_config *cfg)
468 {
469 __be32 addr;
470 int plen;
471
472 memset(cfg, 0, sizeof(*cfg));
473 cfg->fc_nlinfo.nl_net = net;
474
475 if (rt->rt_dst.sa_family != AF_INET)
476 return -EAFNOSUPPORT;
477
478 /*
479 * Check mask for validity:
480 * a) it must be contiguous.
481 * b) destination must have all host bits clear.
482 * c) if application forgot to set correct family (AF_INET),
483 * reject request unless it is absolutely clear i.e.
484 * both family and mask are zero.
485 */
486 plen = 32;
487 addr = sk_extract_addr(&rt->rt_dst);
488 if (!(rt->rt_flags & RTF_HOST)) {
489 __be32 mask = sk_extract_addr(&rt->rt_genmask);
490
491 if (rt->rt_genmask.sa_family != AF_INET) {
492 if (mask || rt->rt_genmask.sa_family)
493 return -EAFNOSUPPORT;
494 }
495
496 if (bad_mask(mask, addr))
497 return -EINVAL;
498
499 plen = inet_mask_len(mask);
500 }
501
502 cfg->fc_dst_len = plen;
503 cfg->fc_dst = addr;
504
505 if (cmd != SIOCDELRT) {
506 cfg->fc_nlflags = NLM_F_CREATE;
507 cfg->fc_protocol = RTPROT_BOOT;
508 }
509
510 if (rt->rt_metric)
511 cfg->fc_priority = rt->rt_metric - 1;
512
513 if (rt->rt_flags & RTF_REJECT) {
514 cfg->fc_scope = RT_SCOPE_HOST;
515 cfg->fc_type = RTN_UNREACHABLE;
516 return 0;
517 }
518
519 cfg->fc_scope = RT_SCOPE_NOWHERE;
520 cfg->fc_type = RTN_UNICAST;
521
522 if (rt->rt_dev) {
523 char *colon;
524 struct net_device *dev;
525 char devname[IFNAMSIZ];
526
527 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
528 return -EFAULT;
529
530 devname[IFNAMSIZ-1] = 0;
531 colon = strchr(devname, ':');
532 if (colon)
533 *colon = 0;
534 dev = __dev_get_by_name(net, devname);
535 if (!dev)
536 return -ENODEV;
537 cfg->fc_oif = dev->ifindex;
538 cfg->fc_table = l3mdev_fib_table(dev);
539 if (colon) {
540 const struct in_ifaddr *ifa;
541 struct in_device *in_dev;
542
543 in_dev = __in_dev_get_rtnl(dev);
544 if (!in_dev)
545 return -ENODEV;
546
547 *colon = ':';
548
549 rcu_read_lock();
550 in_dev_for_each_ifa_rcu(ifa, in_dev) {
551 if (strcmp(ifa->ifa_label, devname) == 0)
552 break;
553 }
554 rcu_read_unlock();
555
556 if (!ifa)
557 return -ENODEV;
558 cfg->fc_prefsrc = ifa->ifa_local;
559 }
560 }
561
562 addr = sk_extract_addr(&rt->rt_gateway);
563 if (rt->rt_gateway.sa_family == AF_INET && addr) {
564 unsigned int addr_type;
565
566 cfg->fc_gw4 = addr;
567 cfg->fc_gw_family = AF_INET;
568 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
569 if (rt->rt_flags & RTF_GATEWAY &&
570 addr_type == RTN_UNICAST)
571 cfg->fc_scope = RT_SCOPE_UNIVERSE;
572 }
573
574 if (cmd == SIOCDELRT)
575 return 0;
576
577 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
578 return -EINVAL;
579
580 if (cfg->fc_scope == RT_SCOPE_NOWHERE)
581 cfg->fc_scope = RT_SCOPE_LINK;
582
583 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
584 struct nlattr *mx;
585 int len = 0;
586
587 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
588 if (!mx)
589 return -ENOMEM;
590
591 if (rt->rt_flags & RTF_MTU)
592 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
593
594 if (rt->rt_flags & RTF_WINDOW)
595 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
596
597 if (rt->rt_flags & RTF_IRTT)
598 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
599
600 cfg->fc_mx = mx;
601 cfg->fc_mx_len = len;
602 }
603
604 return 0;
605 }
606
607 /*
608 * Handle IP routing ioctl calls.
609 * These are used to manipulate the routing tables
610 */
ip_rt_ioctl(struct net * net,unsigned int cmd,struct rtentry * rt)611 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
612 {
613 struct fib_config cfg;
614 int err;
615
616 switch (cmd) {
617 case SIOCADDRT: /* Add a route */
618 case SIOCDELRT: /* Delete a route */
619 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
620 return -EPERM;
621
622 rtnl_lock();
623 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
624 if (err == 0) {
625 struct fib_table *tb;
626
627 if (cmd == SIOCDELRT) {
628 tb = fib_get_table(net, cfg.fc_table);
629 if (tb)
630 err = fib_table_delete(net, tb, &cfg,
631 NULL);
632 else
633 err = -ESRCH;
634 } else {
635 tb = fib_new_table(net, cfg.fc_table);
636 if (tb)
637 err = fib_table_insert(net, tb,
638 &cfg, NULL);
639 else
640 err = -ENOBUFS;
641 }
642
643 /* allocated by rtentry_to_fib_config() */
644 kfree(cfg.fc_mx);
645 }
646 rtnl_unlock();
647 return err;
648 }
649 return -EINVAL;
650 }
651
652 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
653 [RTA_UNSPEC] = { .strict_start_type = RTA_DPORT + 1 },
654 [RTA_DST] = { .type = NLA_U32 },
655 [RTA_SRC] = { .type = NLA_U32 },
656 [RTA_IIF] = { .type = NLA_U32 },
657 [RTA_OIF] = { .type = NLA_U32 },
658 [RTA_GATEWAY] = { .type = NLA_U32 },
659 [RTA_PRIORITY] = { .type = NLA_U32 },
660 [RTA_PREFSRC] = { .type = NLA_U32 },
661 [RTA_METRICS] = { .type = NLA_NESTED },
662 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
663 [RTA_FLOW] = { .type = NLA_U32 },
664 [RTA_ENCAP_TYPE] = { .type = NLA_U16 },
665 [RTA_ENCAP] = { .type = NLA_NESTED },
666 [RTA_UID] = { .type = NLA_U32 },
667 [RTA_MARK] = { .type = NLA_U32 },
668 [RTA_TABLE] = { .type = NLA_U32 },
669 [RTA_IP_PROTO] = { .type = NLA_U8 },
670 [RTA_SPORT] = { .type = NLA_U16 },
671 [RTA_DPORT] = { .type = NLA_U16 },
672 [RTA_NH_ID] = { .type = NLA_U32 },
673 };
674
fib_gw_from_via(struct fib_config * cfg,struct nlattr * nla,struct netlink_ext_ack * extack)675 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
676 struct netlink_ext_ack *extack)
677 {
678 struct rtvia *via;
679 int alen;
680
681 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
682 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
683 return -EINVAL;
684 }
685
686 via = nla_data(nla);
687 alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
688
689 switch (via->rtvia_family) {
690 case AF_INET:
691 if (alen != sizeof(__be32)) {
692 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
693 return -EINVAL;
694 }
695 cfg->fc_gw_family = AF_INET;
696 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
697 break;
698 case AF_INET6:
699 #if IS_ENABLED(CONFIG_IPV6)
700 if (alen != sizeof(struct in6_addr)) {
701 NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
702 return -EINVAL;
703 }
704 cfg->fc_gw_family = AF_INET6;
705 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
706 #else
707 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
708 return -EINVAL;
709 #endif
710 break;
711 default:
712 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
713 return -EINVAL;
714 }
715
716 return 0;
717 }
718
rtm_to_fib_config(struct net * net,struct sk_buff * skb,struct nlmsghdr * nlh,struct fib_config * cfg,struct netlink_ext_ack * extack)719 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
720 struct nlmsghdr *nlh, struct fib_config *cfg,
721 struct netlink_ext_ack *extack)
722 {
723 bool has_gw = false, has_via = false;
724 struct nlattr *attr;
725 int err, remaining;
726 struct rtmsg *rtm;
727
728 err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
729 rtm_ipv4_policy, extack);
730 if (err < 0)
731 goto errout;
732
733 memset(cfg, 0, sizeof(*cfg));
734
735 rtm = nlmsg_data(nlh);
736 cfg->fc_dst_len = rtm->rtm_dst_len;
737 cfg->fc_tos = rtm->rtm_tos;
738 cfg->fc_table = rtm->rtm_table;
739 cfg->fc_protocol = rtm->rtm_protocol;
740 cfg->fc_scope = rtm->rtm_scope;
741 cfg->fc_type = rtm->rtm_type;
742 cfg->fc_flags = rtm->rtm_flags;
743 cfg->fc_nlflags = nlh->nlmsg_flags;
744
745 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
746 cfg->fc_nlinfo.nlh = nlh;
747 cfg->fc_nlinfo.nl_net = net;
748
749 if (cfg->fc_type > RTN_MAX) {
750 NL_SET_ERR_MSG(extack, "Invalid route type");
751 err = -EINVAL;
752 goto errout;
753 }
754
755 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
756 switch (nla_type(attr)) {
757 case RTA_DST:
758 cfg->fc_dst = nla_get_be32(attr);
759 break;
760 case RTA_OIF:
761 cfg->fc_oif = nla_get_u32(attr);
762 break;
763 case RTA_GATEWAY:
764 has_gw = true;
765 cfg->fc_gw4 = nla_get_be32(attr);
766 if (cfg->fc_gw4)
767 cfg->fc_gw_family = AF_INET;
768 break;
769 case RTA_VIA:
770 has_via = true;
771 err = fib_gw_from_via(cfg, attr, extack);
772 if (err)
773 goto errout;
774 break;
775 case RTA_PRIORITY:
776 cfg->fc_priority = nla_get_u32(attr);
777 break;
778 case RTA_PREFSRC:
779 cfg->fc_prefsrc = nla_get_be32(attr);
780 break;
781 case RTA_METRICS:
782 cfg->fc_mx = nla_data(attr);
783 cfg->fc_mx_len = nla_len(attr);
784 break;
785 case RTA_MULTIPATH:
786 err = lwtunnel_valid_encap_type_attr(nla_data(attr),
787 nla_len(attr),
788 extack);
789 if (err < 0)
790 goto errout;
791 cfg->fc_mp = nla_data(attr);
792 cfg->fc_mp_len = nla_len(attr);
793 break;
794 case RTA_FLOW:
795 cfg->fc_flow = nla_get_u32(attr);
796 break;
797 case RTA_TABLE:
798 cfg->fc_table = nla_get_u32(attr);
799 break;
800 case RTA_ENCAP:
801 cfg->fc_encap = attr;
802 break;
803 case RTA_ENCAP_TYPE:
804 cfg->fc_encap_type = nla_get_u16(attr);
805 err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
806 extack);
807 if (err < 0)
808 goto errout;
809 break;
810 case RTA_NH_ID:
811 cfg->fc_nh_id = nla_get_u32(attr);
812 break;
813 }
814 }
815
816 if (cfg->fc_nh_id) {
817 if (cfg->fc_oif || cfg->fc_gw_family ||
818 cfg->fc_encap || cfg->fc_mp) {
819 NL_SET_ERR_MSG(extack,
820 "Nexthop specification and nexthop id are mutually exclusive");
821 return -EINVAL;
822 }
823 }
824
825 if (has_gw && has_via) {
826 NL_SET_ERR_MSG(extack,
827 "Nexthop configuration can not contain both GATEWAY and VIA");
828 return -EINVAL;
829 }
830
831 return 0;
832 errout:
833 return err;
834 }
835
inet_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)836 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
837 struct netlink_ext_ack *extack)
838 {
839 struct net *net = sock_net(skb->sk);
840 struct fib_config cfg;
841 struct fib_table *tb;
842 int err;
843
844 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
845 if (err < 0)
846 goto errout;
847
848 if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
849 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
850 err = -EINVAL;
851 goto errout;
852 }
853
854 tb = fib_get_table(net, cfg.fc_table);
855 if (!tb) {
856 NL_SET_ERR_MSG(extack, "FIB table does not exist");
857 err = -ESRCH;
858 goto errout;
859 }
860
861 err = fib_table_delete(net, tb, &cfg, extack);
862 errout:
863 return err;
864 }
865
inet_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)866 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
867 struct netlink_ext_ack *extack)
868 {
869 struct net *net = sock_net(skb->sk);
870 struct fib_config cfg;
871 struct fib_table *tb;
872 int err;
873
874 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
875 if (err < 0)
876 goto errout;
877
878 tb = fib_new_table(net, cfg.fc_table);
879 if (!tb) {
880 err = -ENOBUFS;
881 goto errout;
882 }
883
884 err = fib_table_insert(net, tb, &cfg, extack);
885 if (!err && cfg.fc_type == RTN_LOCAL)
886 net->ipv4.fib_has_custom_local_routes = true;
887 errout:
888 return err;
889 }
890
ip_valid_fib_dump_req(struct net * net,const struct nlmsghdr * nlh,struct fib_dump_filter * filter,struct netlink_callback * cb)891 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
892 struct fib_dump_filter *filter,
893 struct netlink_callback *cb)
894 {
895 struct netlink_ext_ack *extack = cb->extack;
896 struct nlattr *tb[RTA_MAX + 1];
897 struct rtmsg *rtm;
898 int err, i;
899
900 ASSERT_RTNL();
901
902 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
903 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
904 return -EINVAL;
905 }
906
907 rtm = nlmsg_data(nlh);
908 if (rtm->rtm_dst_len || rtm->rtm_src_len || rtm->rtm_tos ||
909 rtm->rtm_scope) {
910 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
911 return -EINVAL;
912 }
913
914 if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
915 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
916 return -EINVAL;
917 }
918 if (rtm->rtm_flags & RTM_F_CLONED)
919 filter->dump_routes = false;
920 else
921 filter->dump_exceptions = false;
922
923 filter->flags = rtm->rtm_flags;
924 filter->protocol = rtm->rtm_protocol;
925 filter->rt_type = rtm->rtm_type;
926 filter->table_id = rtm->rtm_table;
927
928 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
929 rtm_ipv4_policy, extack);
930 if (err < 0)
931 return err;
932
933 for (i = 0; i <= RTA_MAX; ++i) {
934 int ifindex;
935
936 if (!tb[i])
937 continue;
938
939 switch (i) {
940 case RTA_TABLE:
941 filter->table_id = nla_get_u32(tb[i]);
942 break;
943 case RTA_OIF:
944 ifindex = nla_get_u32(tb[i]);
945 filter->dev = __dev_get_by_index(net, ifindex);
946 if (!filter->dev)
947 return -ENODEV;
948 break;
949 default:
950 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
951 return -EINVAL;
952 }
953 }
954
955 if (filter->flags || filter->protocol || filter->rt_type ||
956 filter->table_id || filter->dev) {
957 filter->filter_set = 1;
958 cb->answer_flags = NLM_F_DUMP_FILTERED;
959 }
960
961 return 0;
962 }
963 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
964
inet_dump_fib(struct sk_buff * skb,struct netlink_callback * cb)965 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
966 {
967 struct fib_dump_filter filter = { .dump_routes = true,
968 .dump_exceptions = true };
969 const struct nlmsghdr *nlh = cb->nlh;
970 struct net *net = sock_net(skb->sk);
971 unsigned int h, s_h;
972 unsigned int e = 0, s_e;
973 struct fib_table *tb;
974 struct hlist_head *head;
975 int dumped = 0, err;
976
977 if (cb->strict_check) {
978 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
979 if (err < 0)
980 return err;
981 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
982 struct rtmsg *rtm = nlmsg_data(nlh);
983
984 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
985 }
986
987 /* ipv4 does not use prefix flag */
988 if (filter.flags & RTM_F_PREFIX)
989 return skb->len;
990
991 if (filter.table_id) {
992 tb = fib_get_table(net, filter.table_id);
993 if (!tb) {
994 if (rtnl_msg_family(cb->nlh) != PF_INET)
995 return skb->len;
996
997 NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
998 return -ENOENT;
999 }
1000
1001 rcu_read_lock();
1002 err = fib_table_dump(tb, skb, cb, &filter);
1003 rcu_read_unlock();
1004 return skb->len ? : err;
1005 }
1006
1007 s_h = cb->args[0];
1008 s_e = cb->args[1];
1009
1010 rcu_read_lock();
1011
1012 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1013 e = 0;
1014 head = &net->ipv4.fib_table_hash[h];
1015 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1016 if (e < s_e)
1017 goto next;
1018 if (dumped)
1019 memset(&cb->args[2], 0, sizeof(cb->args) -
1020 2 * sizeof(cb->args[0]));
1021 err = fib_table_dump(tb, skb, cb, &filter);
1022 if (err < 0) {
1023 if (likely(skb->len))
1024 goto out;
1025
1026 goto out_err;
1027 }
1028 dumped = 1;
1029 next:
1030 e++;
1031 }
1032 }
1033 out:
1034 err = skb->len;
1035 out_err:
1036 rcu_read_unlock();
1037
1038 cb->args[1] = e;
1039 cb->args[0] = h;
1040
1041 return err;
1042 }
1043
1044 /* Prepare and feed intra-kernel routing request.
1045 * Really, it should be netlink message, but :-( netlink
1046 * can be not configured, so that we feed it directly
1047 * to fib engine. It is legal, because all events occur
1048 * only when netlink is already locked.
1049 */
fib_magic(int cmd,int type,__be32 dst,int dst_len,struct in_ifaddr * ifa,u32 rt_priority)1050 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1051 struct in_ifaddr *ifa, u32 rt_priority)
1052 {
1053 struct net *net = dev_net(ifa->ifa_dev->dev);
1054 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1055 struct fib_table *tb;
1056 struct fib_config cfg = {
1057 .fc_protocol = RTPROT_KERNEL,
1058 .fc_type = type,
1059 .fc_dst = dst,
1060 .fc_dst_len = dst_len,
1061 .fc_priority = rt_priority,
1062 .fc_prefsrc = ifa->ifa_local,
1063 .fc_oif = ifa->ifa_dev->dev->ifindex,
1064 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1065 .fc_nlinfo = {
1066 .nl_net = net,
1067 },
1068 };
1069
1070 if (!tb_id)
1071 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1072
1073 tb = fib_new_table(net, tb_id);
1074 if (!tb)
1075 return;
1076
1077 cfg.fc_table = tb->tb_id;
1078
1079 if (type != RTN_LOCAL)
1080 cfg.fc_scope = RT_SCOPE_LINK;
1081 else
1082 cfg.fc_scope = RT_SCOPE_HOST;
1083
1084 if (cmd == RTM_NEWROUTE)
1085 fib_table_insert(net, tb, &cfg, NULL);
1086 else
1087 fib_table_delete(net, tb, &cfg, NULL);
1088 }
1089
fib_add_ifaddr(struct in_ifaddr * ifa)1090 void fib_add_ifaddr(struct in_ifaddr *ifa)
1091 {
1092 struct in_device *in_dev = ifa->ifa_dev;
1093 struct net_device *dev = in_dev->dev;
1094 struct in_ifaddr *prim = ifa;
1095 __be32 mask = ifa->ifa_mask;
1096 __be32 addr = ifa->ifa_local;
1097 __be32 prefix = ifa->ifa_address & mask;
1098
1099 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1100 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1101 if (!prim) {
1102 pr_warn("%s: bug: prim == NULL\n", __func__);
1103 return;
1104 }
1105 }
1106
1107 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1108
1109 if (!(dev->flags & IFF_UP))
1110 return;
1111
1112 /* Add broadcast address, if it is explicitly assigned. */
1113 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
1114 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1115 prim, 0);
1116
1117 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1118 (prefix != addr || ifa->ifa_prefixlen < 32)) {
1119 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1120 fib_magic(RTM_NEWROUTE,
1121 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1122 prefix, ifa->ifa_prefixlen, prim,
1123 ifa->ifa_rt_priority);
1124
1125 /* Add network specific broadcasts, when it takes a sense */
1126 if (ifa->ifa_prefixlen < 31) {
1127 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32,
1128 prim, 0);
1129 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1130 32, prim, 0);
1131 }
1132 }
1133 }
1134
fib_modify_prefix_metric(struct in_ifaddr * ifa,u32 new_metric)1135 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1136 {
1137 __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1138 struct in_device *in_dev = ifa->ifa_dev;
1139 struct net_device *dev = in_dev->dev;
1140
1141 if (!(dev->flags & IFF_UP) ||
1142 ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1143 ipv4_is_zeronet(prefix) ||
1144 (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1145 return;
1146
1147 /* add the new */
1148 fib_magic(RTM_NEWROUTE,
1149 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1150 prefix, ifa->ifa_prefixlen, ifa, new_metric);
1151
1152 /* delete the old */
1153 fib_magic(RTM_DELROUTE,
1154 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1155 prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1156 }
1157
1158 /* Delete primary or secondary address.
1159 * Optionally, on secondary address promotion consider the addresses
1160 * from subnet iprim as deleted, even if they are in device list.
1161 * In this case the secondary ifa can be in device list.
1162 */
fib_del_ifaddr(struct in_ifaddr * ifa,struct in_ifaddr * iprim)1163 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1164 {
1165 struct in_device *in_dev = ifa->ifa_dev;
1166 struct net_device *dev = in_dev->dev;
1167 struct in_ifaddr *ifa1;
1168 struct in_ifaddr *prim = ifa, *prim1 = NULL;
1169 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1170 __be32 any = ifa->ifa_address & ifa->ifa_mask;
1171 #define LOCAL_OK 1
1172 #define BRD_OK 2
1173 #define BRD0_OK 4
1174 #define BRD1_OK 8
1175 unsigned int ok = 0;
1176 int subnet = 0; /* Primary network */
1177 int gone = 1; /* Address is missing */
1178 int same_prefsrc = 0; /* Another primary with same IP */
1179
1180 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1181 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1182 if (!prim) {
1183 /* if the device has been deleted, we don't perform
1184 * address promotion
1185 */
1186 if (!in_dev->dead)
1187 pr_warn("%s: bug: prim == NULL\n", __func__);
1188 return;
1189 }
1190 if (iprim && iprim != prim) {
1191 pr_warn("%s: bug: iprim != prim\n", __func__);
1192 return;
1193 }
1194 } else if (!ipv4_is_zeronet(any) &&
1195 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1196 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1197 fib_magic(RTM_DELROUTE,
1198 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1199 any, ifa->ifa_prefixlen, prim, 0);
1200 subnet = 1;
1201 }
1202
1203 if (in_dev->dead)
1204 goto no_promotions;
1205
1206 /* Deletion is more complicated than add.
1207 * We should take care of not to delete too much :-)
1208 *
1209 * Scan address list to be sure that addresses are really gone.
1210 */
1211 rcu_read_lock();
1212 in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1213 if (ifa1 == ifa) {
1214 /* promotion, keep the IP */
1215 gone = 0;
1216 continue;
1217 }
1218 /* Ignore IFAs from our subnet */
1219 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1220 inet_ifa_match(ifa1->ifa_address, iprim))
1221 continue;
1222
1223 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1224 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1225 /* Another address from our subnet? */
1226 if (ifa1->ifa_mask == prim->ifa_mask &&
1227 inet_ifa_match(ifa1->ifa_address, prim))
1228 prim1 = prim;
1229 else {
1230 /* We reached the secondaries, so
1231 * same_prefsrc should be determined.
1232 */
1233 if (!same_prefsrc)
1234 continue;
1235 /* Search new prim1 if ifa1 is not
1236 * using the current prim1
1237 */
1238 if (!prim1 ||
1239 ifa1->ifa_mask != prim1->ifa_mask ||
1240 !inet_ifa_match(ifa1->ifa_address, prim1))
1241 prim1 = inet_ifa_byprefix(in_dev,
1242 ifa1->ifa_address,
1243 ifa1->ifa_mask);
1244 if (!prim1)
1245 continue;
1246 if (prim1->ifa_local != prim->ifa_local)
1247 continue;
1248 }
1249 } else {
1250 if (prim->ifa_local != ifa1->ifa_local)
1251 continue;
1252 prim1 = ifa1;
1253 if (prim != prim1)
1254 same_prefsrc = 1;
1255 }
1256 if (ifa->ifa_local == ifa1->ifa_local)
1257 ok |= LOCAL_OK;
1258 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1259 ok |= BRD_OK;
1260 if (brd == ifa1->ifa_broadcast)
1261 ok |= BRD1_OK;
1262 if (any == ifa1->ifa_broadcast)
1263 ok |= BRD0_OK;
1264 /* primary has network specific broadcasts */
1265 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1266 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1267 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1268
1269 if (!ipv4_is_zeronet(any1)) {
1270 if (ifa->ifa_broadcast == brd1 ||
1271 ifa->ifa_broadcast == any1)
1272 ok |= BRD_OK;
1273 if (brd == brd1 || brd == any1)
1274 ok |= BRD1_OK;
1275 if (any == brd1 || any == any1)
1276 ok |= BRD0_OK;
1277 }
1278 }
1279 }
1280 rcu_read_unlock();
1281
1282 no_promotions:
1283 if (!(ok & BRD_OK))
1284 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1285 prim, 0);
1286 if (subnet && ifa->ifa_prefixlen < 31) {
1287 if (!(ok & BRD1_OK))
1288 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1289 prim, 0);
1290 if (!(ok & BRD0_OK))
1291 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1292 prim, 0);
1293 }
1294 if (!(ok & LOCAL_OK)) {
1295 unsigned int addr_type;
1296
1297 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1298
1299 /* Check, that this local address finally disappeared. */
1300 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1301 ifa->ifa_local);
1302 if (gone && addr_type != RTN_LOCAL) {
1303 /* And the last, but not the least thing.
1304 * We must flush stray FIB entries.
1305 *
1306 * First of all, we scan fib_info list searching
1307 * for stray nexthop entries, then ignite fib_flush.
1308 */
1309 if (fib_sync_down_addr(dev, ifa->ifa_local))
1310 fib_flush(dev_net(dev));
1311 }
1312 }
1313 #undef LOCAL_OK
1314 #undef BRD_OK
1315 #undef BRD0_OK
1316 #undef BRD1_OK
1317 }
1318
nl_fib_lookup(struct net * net,struct fib_result_nl * frn)1319 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1320 {
1321
1322 struct fib_result res;
1323 struct flowi4 fl4 = {
1324 .flowi4_mark = frn->fl_mark,
1325 .daddr = frn->fl_addr,
1326 .flowi4_tos = frn->fl_tos,
1327 .flowi4_scope = frn->fl_scope,
1328 };
1329 struct fib_table *tb;
1330
1331 rcu_read_lock();
1332
1333 tb = fib_get_table(net, frn->tb_id_in);
1334
1335 frn->err = -ENOENT;
1336 if (tb) {
1337 local_bh_disable();
1338
1339 frn->tb_id = tb->tb_id;
1340 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1341
1342 if (!frn->err) {
1343 frn->prefixlen = res.prefixlen;
1344 frn->nh_sel = res.nh_sel;
1345 frn->type = res.type;
1346 frn->scope = res.scope;
1347 }
1348 local_bh_enable();
1349 }
1350
1351 rcu_read_unlock();
1352 }
1353
nl_fib_input(struct sk_buff * skb)1354 static void nl_fib_input(struct sk_buff *skb)
1355 {
1356 struct net *net;
1357 struct fib_result_nl *frn;
1358 struct nlmsghdr *nlh;
1359 u32 portid;
1360
1361 net = sock_net(skb->sk);
1362 nlh = nlmsg_hdr(skb);
1363 if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1364 skb->len < nlh->nlmsg_len ||
1365 nlmsg_len(nlh) < sizeof(*frn))
1366 return;
1367
1368 skb = netlink_skb_clone(skb, GFP_KERNEL);
1369 if (!skb)
1370 return;
1371 nlh = nlmsg_hdr(skb);
1372
1373 frn = (struct fib_result_nl *) nlmsg_data(nlh);
1374 nl_fib_lookup(net, frn);
1375
1376 portid = NETLINK_CB(skb).portid; /* netlink portid */
1377 NETLINK_CB(skb).portid = 0; /* from kernel */
1378 NETLINK_CB(skb).dst_group = 0; /* unicast */
1379 netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
1380 }
1381
nl_fib_lookup_init(struct net * net)1382 static int __net_init nl_fib_lookup_init(struct net *net)
1383 {
1384 struct sock *sk;
1385 struct netlink_kernel_cfg cfg = {
1386 .input = nl_fib_input,
1387 };
1388
1389 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1390 if (!sk)
1391 return -EAFNOSUPPORT;
1392 net->ipv4.fibnl = sk;
1393 return 0;
1394 }
1395
nl_fib_lookup_exit(struct net * net)1396 static void nl_fib_lookup_exit(struct net *net)
1397 {
1398 netlink_kernel_release(net->ipv4.fibnl);
1399 net->ipv4.fibnl = NULL;
1400 }
1401
fib_disable_ip(struct net_device * dev,unsigned long event,bool force)1402 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1403 bool force)
1404 {
1405 if (fib_sync_down_dev(dev, event, force))
1406 fib_flush(dev_net(dev));
1407 else
1408 rt_cache_flush(dev_net(dev));
1409 arp_ifdown(dev);
1410 }
1411
fib_inetaddr_event(struct notifier_block * this,unsigned long event,void * ptr)1412 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1413 {
1414 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1415 struct net_device *dev = ifa->ifa_dev->dev;
1416 struct net *net = dev_net(dev);
1417
1418 switch (event) {
1419 case NETDEV_UP:
1420 fib_add_ifaddr(ifa);
1421 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1422 fib_sync_up(dev, RTNH_F_DEAD);
1423 #endif
1424 atomic_inc(&net->ipv4.dev_addr_genid);
1425 rt_cache_flush(dev_net(dev));
1426 break;
1427 case NETDEV_DOWN:
1428 fib_del_ifaddr(ifa, NULL);
1429 atomic_inc(&net->ipv4.dev_addr_genid);
1430 if (!ifa->ifa_dev->ifa_list) {
1431 /* Last address was deleted from this interface.
1432 * Disable IP.
1433 */
1434 fib_disable_ip(dev, event, true);
1435 } else {
1436 rt_cache_flush(dev_net(dev));
1437 }
1438 break;
1439 }
1440 return NOTIFY_DONE;
1441 }
1442
fib_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1443 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1444 {
1445 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1446 struct netdev_notifier_changeupper_info *upper_info = ptr;
1447 struct netdev_notifier_info_ext *info_ext = ptr;
1448 struct in_device *in_dev;
1449 struct net *net = dev_net(dev);
1450 struct in_ifaddr *ifa;
1451 unsigned int flags;
1452
1453 if (event == NETDEV_UNREGISTER) {
1454 fib_disable_ip(dev, event, true);
1455 rt_flush_dev(dev);
1456 return NOTIFY_DONE;
1457 }
1458
1459 in_dev = __in_dev_get_rtnl(dev);
1460 if (!in_dev)
1461 return NOTIFY_DONE;
1462
1463 switch (event) {
1464 case NETDEV_UP:
1465 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1466 fib_add_ifaddr(ifa);
1467 }
1468 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1469 fib_sync_up(dev, RTNH_F_DEAD);
1470 #endif
1471 atomic_inc(&net->ipv4.dev_addr_genid);
1472 rt_cache_flush(net);
1473 break;
1474 case NETDEV_DOWN:
1475 fib_disable_ip(dev, event, false);
1476 break;
1477 case NETDEV_CHANGE:
1478 flags = dev_get_flags(dev);
1479 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1480 fib_sync_up(dev, RTNH_F_LINKDOWN);
1481 else
1482 fib_sync_down_dev(dev, event, false);
1483 rt_cache_flush(net);
1484 break;
1485 case NETDEV_CHANGEMTU:
1486 fib_sync_mtu(dev, info_ext->ext.mtu);
1487 rt_cache_flush(net);
1488 break;
1489 case NETDEV_CHANGEUPPER:
1490 upper_info = ptr;
1491 /* flush all routes if dev is linked to or unlinked from
1492 * an L3 master device (e.g., VRF)
1493 */
1494 if (upper_info->upper_dev &&
1495 netif_is_l3_master(upper_info->upper_dev))
1496 fib_disable_ip(dev, NETDEV_DOWN, true);
1497 break;
1498 }
1499 return NOTIFY_DONE;
1500 }
1501
1502 static struct notifier_block fib_inetaddr_notifier = {
1503 .notifier_call = fib_inetaddr_event,
1504 };
1505
1506 static struct notifier_block fib_netdev_notifier = {
1507 .notifier_call = fib_netdev_event,
1508 };
1509
ip_fib_net_init(struct net * net)1510 static int __net_init ip_fib_net_init(struct net *net)
1511 {
1512 int err;
1513 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1514
1515 err = fib4_notifier_init(net);
1516 if (err)
1517 return err;
1518
1519 /* Avoid false sharing : Use at least a full cache line */
1520 size = max_t(size_t, size, L1_CACHE_BYTES);
1521
1522 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1523 if (!net->ipv4.fib_table_hash) {
1524 err = -ENOMEM;
1525 goto err_table_hash_alloc;
1526 }
1527
1528 err = fib4_rules_init(net);
1529 if (err < 0)
1530 goto err_rules_init;
1531 return 0;
1532
1533 err_rules_init:
1534 kfree(net->ipv4.fib_table_hash);
1535 err_table_hash_alloc:
1536 fib4_notifier_exit(net);
1537 return err;
1538 }
1539
ip_fib_net_exit(struct net * net)1540 static void ip_fib_net_exit(struct net *net)
1541 {
1542 int i;
1543
1544 rtnl_lock();
1545 #ifdef CONFIG_IP_MULTIPLE_TABLES
1546 RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1547 RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1548 #endif
1549 /* Destroy the tables in reverse order to guarantee that the
1550 * local table, ID 255, is destroyed before the main table, ID
1551 * 254. This is necessary as the local table may contain
1552 * references to data contained in the main table.
1553 */
1554 for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1555 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1556 struct hlist_node *tmp;
1557 struct fib_table *tb;
1558
1559 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1560 hlist_del(&tb->tb_hlist);
1561 fib_table_flush(net, tb, true);
1562 fib_free_table(tb);
1563 }
1564 }
1565
1566 #ifdef CONFIG_IP_MULTIPLE_TABLES
1567 fib4_rules_exit(net);
1568 #endif
1569 rtnl_unlock();
1570 kfree(net->ipv4.fib_table_hash);
1571 fib4_notifier_exit(net);
1572 }
1573
fib_net_init(struct net * net)1574 static int __net_init fib_net_init(struct net *net)
1575 {
1576 int error;
1577
1578 #ifdef CONFIG_IP_ROUTE_CLASSID
1579 net->ipv4.fib_num_tclassid_users = 0;
1580 #endif
1581 error = ip_fib_net_init(net);
1582 if (error < 0)
1583 goto out;
1584 error = nl_fib_lookup_init(net);
1585 if (error < 0)
1586 goto out_nlfl;
1587 error = fib_proc_init(net);
1588 if (error < 0)
1589 goto out_proc;
1590 out:
1591 return error;
1592
1593 out_proc:
1594 nl_fib_lookup_exit(net);
1595 out_nlfl:
1596 ip_fib_net_exit(net);
1597 goto out;
1598 }
1599
fib_net_exit(struct net * net)1600 static void __net_exit fib_net_exit(struct net *net)
1601 {
1602 fib_proc_exit(net);
1603 nl_fib_lookup_exit(net);
1604 ip_fib_net_exit(net);
1605 }
1606
1607 static struct pernet_operations fib_net_ops = {
1608 .init = fib_net_init,
1609 .exit = fib_net_exit,
1610 };
1611
ip_fib_init(void)1612 void __init ip_fib_init(void)
1613 {
1614 fib_trie_init();
1615
1616 register_pernet_subsys(&fib_net_ops);
1617
1618 register_netdevice_notifier(&fib_netdev_notifier);
1619 register_inetaddr_notifier(&fib_inetaddr_notifier);
1620
1621 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1622 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1623 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1624 }
1625
