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/inet_dscp.h>
36 #include <net/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/arp.h>
42 #include <net/ip_fib.h>
43 #include <net/nexthop.h>
44 #include <net/rtnetlink.h>
45 #include <net/xfrm.h>
46 #include <net/l3mdev.h>
47 #include <net/lwtunnel.h>
48 #include <trace/events/fib.h>
49
50 #ifndef CONFIG_IP_MULTIPLE_TABLES
51
fib4_rules_init(struct net * net)52 static int __net_init fib4_rules_init(struct net *net)
53 {
54 struct fib_table *local_table, *main_table;
55
56 main_table = fib_trie_table(RT_TABLE_MAIN, NULL);
57 if (!main_table)
58 return -ENOMEM;
59
60 local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
61 if (!local_table)
62 goto fail;
63
64 hlist_add_head_rcu(&local_table->tb_hlist,
65 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
66 hlist_add_head_rcu(&main_table->tb_hlist,
67 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
68 return 0;
69
70 fail:
71 fib_free_table(main_table);
72 return -ENOMEM;
73 }
74 #else
75
fib_new_table(struct net * net,u32 id)76 struct fib_table *fib_new_table(struct net *net, u32 id)
77 {
78 struct fib_table *tb, *alias = NULL;
79 unsigned int h;
80
81 if (id == 0)
82 id = RT_TABLE_MAIN;
83 tb = fib_get_table(net, id);
84 if (tb)
85 return tb;
86
87 if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
88 alias = fib_new_table(net, RT_TABLE_MAIN);
89
90 tb = fib_trie_table(id, alias);
91 if (!tb)
92 return NULL;
93
94 switch (id) {
95 case RT_TABLE_MAIN:
96 rcu_assign_pointer(net->ipv4.fib_main, tb);
97 break;
98 case RT_TABLE_DEFAULT:
99 rcu_assign_pointer(net->ipv4.fib_default, tb);
100 break;
101 default:
102 break;
103 }
104
105 h = id & (FIB_TABLE_HASHSZ - 1);
106 hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
107 return tb;
108 }
109 EXPORT_SYMBOL_GPL(fib_new_table);
110
111 /* caller must hold either rtnl or rcu read lock */
fib_get_table(struct net * net,u32 id)112 struct fib_table *fib_get_table(struct net *net, u32 id)
113 {
114 struct fib_table *tb;
115 struct hlist_head *head;
116 unsigned int h;
117
118 if (id == 0)
119 id = RT_TABLE_MAIN;
120 h = id & (FIB_TABLE_HASHSZ - 1);
121
122 head = &net->ipv4.fib_table_hash[h];
123 hlist_for_each_entry_rcu(tb, head, tb_hlist,
124 lockdep_rtnl_is_held()) {
125 if (tb->tb_id == id)
126 return tb;
127 }
128 return NULL;
129 }
130 #endif /* CONFIG_IP_MULTIPLE_TABLES */
131
fib_replace_table(struct net * net,struct fib_table * old,struct fib_table * new)132 static void fib_replace_table(struct net *net, struct fib_table *old,
133 struct fib_table *new)
134 {
135 #ifdef CONFIG_IP_MULTIPLE_TABLES
136 switch (new->tb_id) {
137 case RT_TABLE_MAIN:
138 rcu_assign_pointer(net->ipv4.fib_main, new);
139 break;
140 case RT_TABLE_DEFAULT:
141 rcu_assign_pointer(net->ipv4.fib_default, new);
142 break;
143 default:
144 break;
145 }
146
147 #endif
148 /* replace the old table in the hlist */
149 hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
150 }
151
fib_unmerge(struct net * net)152 int fib_unmerge(struct net *net)
153 {
154 struct fib_table *old, *new, *main_table;
155
156 /* attempt to fetch local table if it has been allocated */
157 old = fib_get_table(net, RT_TABLE_LOCAL);
158 if (!old)
159 return 0;
160
161 new = fib_trie_unmerge(old);
162 if (!new)
163 return -ENOMEM;
164
165 /* table is already unmerged */
166 if (new == old)
167 return 0;
168
169 /* replace merged table with clean table */
170 fib_replace_table(net, old, new);
171 fib_free_table(old);
172
173 /* attempt to fetch main table if it has been allocated */
174 main_table = fib_get_table(net, RT_TABLE_MAIN);
175 if (!main_table)
176 return 0;
177
178 /* flush local entries from main table */
179 fib_table_flush_external(main_table);
180
181 return 0;
182 }
183
fib_flush(struct net * net)184 void fib_flush(struct net *net)
185 {
186 int flushed = 0;
187 unsigned int h;
188
189 for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
190 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
191 struct hlist_node *tmp;
192 struct fib_table *tb;
193
194 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
195 flushed += fib_table_flush(net, tb, false);
196 }
197
198 if (flushed)
199 rt_cache_flush(net);
200 }
201
202 /*
203 * Find address type as if only "dev" was present in the system. If
204 * on_dev is NULL then all interfaces are taken into consideration.
205 */
__inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr,u32 tb_id)206 static inline unsigned int __inet_dev_addr_type(struct net *net,
207 const struct net_device *dev,
208 __be32 addr, u32 tb_id)
209 {
210 struct flowi4 fl4 = { .daddr = addr };
211 struct fib_result res;
212 unsigned int ret = RTN_BROADCAST;
213 struct fib_table *table;
214
215 if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
216 return RTN_BROADCAST;
217 if (ipv4_is_multicast(addr))
218 return RTN_MULTICAST;
219
220 rcu_read_lock();
221
222 table = fib_get_table(net, tb_id);
223 if (table) {
224 ret = RTN_UNICAST;
225 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
226 struct fib_nh_common *nhc = fib_info_nhc(res.fi, 0);
227
228 if (!dev || dev == nhc->nhc_dev)
229 ret = res.type;
230 }
231 }
232
233 rcu_read_unlock();
234 return ret;
235 }
236
inet_addr_type_table(struct net * net,__be32 addr,u32 tb_id)237 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
238 {
239 return __inet_dev_addr_type(net, NULL, addr, tb_id);
240 }
241 EXPORT_SYMBOL(inet_addr_type_table);
242
inet_addr_type(struct net * net,__be32 addr)243 unsigned int inet_addr_type(struct net *net, __be32 addr)
244 {
245 return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
246 }
247 EXPORT_SYMBOL(inet_addr_type);
248
inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr)249 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
250 __be32 addr)
251 {
252 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
253
254 return __inet_dev_addr_type(net, dev, addr, rt_table);
255 }
256 EXPORT_SYMBOL(inet_dev_addr_type);
257
258 /* inet_addr_type with dev == NULL but using the table from a dev
259 * if one is associated
260 */
inet_addr_type_dev_table(struct net * net,const struct net_device * dev,__be32 addr)261 unsigned int inet_addr_type_dev_table(struct net *net,
262 const struct net_device *dev,
263 __be32 addr)
264 {
265 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
266
267 return __inet_dev_addr_type(net, NULL, addr, rt_table);
268 }
269 EXPORT_SYMBOL(inet_addr_type_dev_table);
270
fib_compute_spec_dst(struct sk_buff * skb)271 __be32 fib_compute_spec_dst(struct sk_buff *skb)
272 {
273 struct net_device *dev = skb->dev;
274 struct in_device *in_dev;
275 struct fib_result res;
276 struct rtable *rt;
277 struct net *net;
278 int scope;
279
280 rt = skb_rtable(skb);
281 if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
282 RTCF_LOCAL)
283 return ip_hdr(skb)->daddr;
284
285 in_dev = __in_dev_get_rcu(dev);
286
287 net = dev_net(dev);
288
289 scope = RT_SCOPE_UNIVERSE;
290 if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
291 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
292 struct flowi4 fl4 = {
293 .flowi4_iif = LOOPBACK_IFINDEX,
294 .flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev),
295 .daddr = ip_hdr(skb)->saddr,
296 .flowi4_tos = ip_hdr(skb)->tos & IPTOS_RT_MASK,
297 .flowi4_scope = scope,
298 .flowi4_mark = vmark ? skb->mark : 0,
299 };
300 if (!fib_lookup(net, &fl4, &res, 0))
301 return fib_result_prefsrc(net, &res);
302 } else {
303 scope = RT_SCOPE_LINK;
304 }
305
306 return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
307 }
308
fib_info_nh_uses_dev(struct fib_info * fi,const struct net_device * dev)309 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
310 {
311 bool dev_match = false;
312 #ifdef CONFIG_IP_ROUTE_MULTIPATH
313 if (unlikely(fi->nh)) {
314 dev_match = nexthop_uses_dev(fi->nh, dev);
315 } else {
316 int ret;
317
318 for (ret = 0; ret < fib_info_num_path(fi); ret++) {
319 const struct fib_nh_common *nhc = fib_info_nhc(fi, ret);
320
321 if (nhc_l3mdev_matches_dev(nhc, dev)) {
322 dev_match = true;
323 break;
324 }
325 }
326 }
327 #else
328 if (fib_info_nhc(fi, 0)->nhc_dev == dev)
329 dev_match = true;
330 #endif
331
332 return dev_match;
333 }
334 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
335
336 /* Given (packet source, input interface) and optional (dst, oif, tos):
337 * - (main) check, that source is valid i.e. not broadcast or our local
338 * address.
339 * - figure out what "logical" interface this packet arrived
340 * and calculate "specific destination" address.
341 * - check, that packet arrived from expected physical interface.
342 * called with rcu_read_lock()
343 */
__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)344 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
345 u8 tos, int oif, struct net_device *dev,
346 int rpf, struct in_device *idev, u32 *itag)
347 {
348 struct net *net = dev_net(dev);
349 struct flow_keys flkeys;
350 int ret, no_addr;
351 struct fib_result res;
352 struct flowi4 fl4;
353 bool dev_match;
354
355 fl4.flowi4_oif = 0;
356 fl4.flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev);
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_HOST;
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_HOST;
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 /* Within the same container, it is regarded as a martian source,
440 * and the same host but different containers are not.
441 */
442 if (inet_lookup_ifaddr_rcu(net, src))
443 return -EINVAL;
444
445 ok:
446 *itag = 0;
447 return 0;
448 }
449
450 full_check:
451 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
452 }
453
sk_extract_addr(struct sockaddr * addr)454 static inline __be32 sk_extract_addr(struct sockaddr *addr)
455 {
456 return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
457 }
458
put_rtax(struct nlattr * mx,int len,int type,u32 value)459 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
460 {
461 struct nlattr *nla;
462
463 nla = (struct nlattr *) ((char *) mx + len);
464 nla->nla_type = type;
465 nla->nla_len = nla_attr_size(4);
466 *(u32 *) nla_data(nla) = value;
467
468 return len + nla_total_size(4);
469 }
470
rtentry_to_fib_config(struct net * net,int cmd,struct rtentry * rt,struct fib_config * cfg)471 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
472 struct fib_config *cfg)
473 {
474 __be32 addr;
475 int plen;
476
477 memset(cfg, 0, sizeof(*cfg));
478 cfg->fc_nlinfo.nl_net = net;
479
480 if (rt->rt_dst.sa_family != AF_INET)
481 return -EAFNOSUPPORT;
482
483 /*
484 * Check mask for validity:
485 * a) it must be contiguous.
486 * b) destination must have all host bits clear.
487 * c) if application forgot to set correct family (AF_INET),
488 * reject request unless it is absolutely clear i.e.
489 * both family and mask are zero.
490 */
491 plen = 32;
492 addr = sk_extract_addr(&rt->rt_dst);
493 if (!(rt->rt_flags & RTF_HOST)) {
494 __be32 mask = sk_extract_addr(&rt->rt_genmask);
495
496 if (rt->rt_genmask.sa_family != AF_INET) {
497 if (mask || rt->rt_genmask.sa_family)
498 return -EAFNOSUPPORT;
499 }
500
501 if (bad_mask(mask, addr))
502 return -EINVAL;
503
504 plen = inet_mask_len(mask);
505 }
506
507 cfg->fc_dst_len = plen;
508 cfg->fc_dst = addr;
509
510 if (cmd != SIOCDELRT) {
511 cfg->fc_nlflags = NLM_F_CREATE;
512 cfg->fc_protocol = RTPROT_BOOT;
513 }
514
515 if (rt->rt_metric)
516 cfg->fc_priority = rt->rt_metric - 1;
517
518 if (rt->rt_flags & RTF_REJECT) {
519 cfg->fc_scope = RT_SCOPE_HOST;
520 cfg->fc_type = RTN_UNREACHABLE;
521 return 0;
522 }
523
524 cfg->fc_scope = RT_SCOPE_NOWHERE;
525 cfg->fc_type = RTN_UNICAST;
526
527 if (rt->rt_dev) {
528 char *colon;
529 struct net_device *dev;
530 char devname[IFNAMSIZ];
531
532 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
533 return -EFAULT;
534
535 devname[IFNAMSIZ-1] = 0;
536 colon = strchr(devname, ':');
537 if (colon)
538 *colon = 0;
539 dev = __dev_get_by_name(net, devname);
540 if (!dev)
541 return -ENODEV;
542 cfg->fc_oif = dev->ifindex;
543 cfg->fc_table = l3mdev_fib_table(dev);
544 if (colon) {
545 const struct in_ifaddr *ifa;
546 struct in_device *in_dev;
547
548 in_dev = __in_dev_get_rtnl(dev);
549 if (!in_dev)
550 return -ENODEV;
551
552 *colon = ':';
553
554 rcu_read_lock();
555 in_dev_for_each_ifa_rcu(ifa, in_dev) {
556 if (strcmp(ifa->ifa_label, devname) == 0)
557 break;
558 }
559 rcu_read_unlock();
560
561 if (!ifa)
562 return -ENODEV;
563 cfg->fc_prefsrc = ifa->ifa_local;
564 }
565 }
566
567 addr = sk_extract_addr(&rt->rt_gateway);
568 if (rt->rt_gateway.sa_family == AF_INET && addr) {
569 unsigned int addr_type;
570
571 cfg->fc_gw4 = addr;
572 cfg->fc_gw_family = AF_INET;
573 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
574 if (rt->rt_flags & RTF_GATEWAY &&
575 addr_type == RTN_UNICAST)
576 cfg->fc_scope = RT_SCOPE_UNIVERSE;
577 }
578
579 if (!cfg->fc_table)
580 cfg->fc_table = RT_TABLE_MAIN;
581
582 if (cmd == SIOCDELRT)
583 return 0;
584
585 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
586 return -EINVAL;
587
588 if (cfg->fc_scope == RT_SCOPE_NOWHERE)
589 cfg->fc_scope = RT_SCOPE_LINK;
590
591 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
592 struct nlattr *mx;
593 int len = 0;
594
595 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
596 if (!mx)
597 return -ENOMEM;
598
599 if (rt->rt_flags & RTF_MTU)
600 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
601
602 if (rt->rt_flags & RTF_WINDOW)
603 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
604
605 if (rt->rt_flags & RTF_IRTT)
606 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
607
608 cfg->fc_mx = mx;
609 cfg->fc_mx_len = len;
610 }
611
612 return 0;
613 }
614
615 /*
616 * Handle IP routing ioctl calls.
617 * These are used to manipulate the routing tables
618 */
ip_rt_ioctl(struct net * net,unsigned int cmd,struct rtentry * rt)619 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
620 {
621 struct fib_config cfg;
622 int err;
623
624 switch (cmd) {
625 case SIOCADDRT: /* Add a route */
626 case SIOCDELRT: /* Delete a route */
627 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
628 return -EPERM;
629
630 rtnl_lock();
631 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
632 if (err == 0) {
633 struct fib_table *tb;
634
635 if (cmd == SIOCDELRT) {
636 tb = fib_get_table(net, cfg.fc_table);
637 if (tb)
638 err = fib_table_delete(net, tb, &cfg,
639 NULL);
640 else
641 err = -ESRCH;
642 } else {
643 tb = fib_new_table(net, cfg.fc_table);
644 if (tb)
645 err = fib_table_insert(net, tb,
646 &cfg, NULL);
647 else
648 err = -ENOBUFS;
649 }
650
651 /* allocated by rtentry_to_fib_config() */
652 kfree(cfg.fc_mx);
653 }
654 rtnl_unlock();
655 return err;
656 }
657 return -EINVAL;
658 }
659
660 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
661 [RTA_UNSPEC] = { .strict_start_type = RTA_DPORT + 1 },
662 [RTA_DST] = { .type = NLA_U32 },
663 [RTA_SRC] = { .type = NLA_U32 },
664 [RTA_IIF] = { .type = NLA_U32 },
665 [RTA_OIF] = { .type = NLA_U32 },
666 [RTA_GATEWAY] = { .type = NLA_U32 },
667 [RTA_PRIORITY] = { .type = NLA_U32 },
668 [RTA_PREFSRC] = { .type = NLA_U32 },
669 [RTA_METRICS] = { .type = NLA_NESTED },
670 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
671 [RTA_FLOW] = { .type = NLA_U32 },
672 [RTA_ENCAP_TYPE] = { .type = NLA_U16 },
673 [RTA_ENCAP] = { .type = NLA_NESTED },
674 [RTA_UID] = { .type = NLA_U32 },
675 [RTA_MARK] = { .type = NLA_U32 },
676 [RTA_TABLE] = { .type = NLA_U32 },
677 [RTA_IP_PROTO] = { .type = NLA_U8 },
678 [RTA_SPORT] = { .type = NLA_U16 },
679 [RTA_DPORT] = { .type = NLA_U16 },
680 [RTA_NH_ID] = { .type = NLA_U32 },
681 };
682
fib_gw_from_via(struct fib_config * cfg,struct nlattr * nla,struct netlink_ext_ack * extack)683 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
684 struct netlink_ext_ack *extack)
685 {
686 struct rtvia *via;
687 int alen;
688
689 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
690 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
691 return -EINVAL;
692 }
693
694 via = nla_data(nla);
695 alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
696
697 switch (via->rtvia_family) {
698 case AF_INET:
699 if (alen != sizeof(__be32)) {
700 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
701 return -EINVAL;
702 }
703 cfg->fc_gw_family = AF_INET;
704 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
705 break;
706 case AF_INET6:
707 #if IS_ENABLED(CONFIG_IPV6)
708 if (alen != sizeof(struct in6_addr)) {
709 NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
710 return -EINVAL;
711 }
712 cfg->fc_gw_family = AF_INET6;
713 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
714 #else
715 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
716 return -EINVAL;
717 #endif
718 break;
719 default:
720 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
721 return -EINVAL;
722 }
723
724 return 0;
725 }
726
rtm_to_fib_config(struct net * net,struct sk_buff * skb,struct nlmsghdr * nlh,struct fib_config * cfg,struct netlink_ext_ack * extack)727 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
728 struct nlmsghdr *nlh, struct fib_config *cfg,
729 struct netlink_ext_ack *extack)
730 {
731 bool has_gw = false, has_via = false;
732 struct nlattr *attr;
733 int err, remaining;
734 struct rtmsg *rtm;
735
736 err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
737 rtm_ipv4_policy, extack);
738 if (err < 0)
739 goto errout;
740
741 memset(cfg, 0, sizeof(*cfg));
742
743 rtm = nlmsg_data(nlh);
744
745 if (!inet_validate_dscp(rtm->rtm_tos)) {
746 NL_SET_ERR_MSG(extack,
747 "Invalid dsfield (tos): ECN bits must be 0");
748 err = -EINVAL;
749 goto errout;
750 }
751 cfg->fc_dscp = inet_dsfield_to_dscp(rtm->rtm_tos);
752
753 cfg->fc_dst_len = rtm->rtm_dst_len;
754 cfg->fc_table = rtm->rtm_table;
755 cfg->fc_protocol = rtm->rtm_protocol;
756 cfg->fc_scope = rtm->rtm_scope;
757 cfg->fc_type = rtm->rtm_type;
758 cfg->fc_flags = rtm->rtm_flags;
759 cfg->fc_nlflags = nlh->nlmsg_flags;
760
761 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
762 cfg->fc_nlinfo.nlh = nlh;
763 cfg->fc_nlinfo.nl_net = net;
764
765 if (cfg->fc_type > RTN_MAX) {
766 NL_SET_ERR_MSG(extack, "Invalid route type");
767 err = -EINVAL;
768 goto errout;
769 }
770
771 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
772 switch (nla_type(attr)) {
773 case RTA_DST:
774 cfg->fc_dst = nla_get_be32(attr);
775 break;
776 case RTA_OIF:
777 cfg->fc_oif = nla_get_u32(attr);
778 break;
779 case RTA_GATEWAY:
780 has_gw = true;
781 cfg->fc_gw4 = nla_get_be32(attr);
782 if (cfg->fc_gw4)
783 cfg->fc_gw_family = AF_INET;
784 break;
785 case RTA_VIA:
786 has_via = true;
787 err = fib_gw_from_via(cfg, attr, extack);
788 if (err)
789 goto errout;
790 break;
791 case RTA_PRIORITY:
792 cfg->fc_priority = nla_get_u32(attr);
793 break;
794 case RTA_PREFSRC:
795 cfg->fc_prefsrc = nla_get_be32(attr);
796 break;
797 case RTA_METRICS:
798 cfg->fc_mx = nla_data(attr);
799 cfg->fc_mx_len = nla_len(attr);
800 break;
801 case RTA_MULTIPATH:
802 err = lwtunnel_valid_encap_type_attr(nla_data(attr),
803 nla_len(attr),
804 extack);
805 if (err < 0)
806 goto errout;
807 cfg->fc_mp = nla_data(attr);
808 cfg->fc_mp_len = nla_len(attr);
809 break;
810 case RTA_FLOW:
811 cfg->fc_flow = nla_get_u32(attr);
812 break;
813 case RTA_TABLE:
814 cfg->fc_table = nla_get_u32(attr);
815 break;
816 case RTA_ENCAP:
817 cfg->fc_encap = attr;
818 break;
819 case RTA_ENCAP_TYPE:
820 cfg->fc_encap_type = nla_get_u16(attr);
821 err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
822 extack);
823 if (err < 0)
824 goto errout;
825 break;
826 case RTA_NH_ID:
827 cfg->fc_nh_id = nla_get_u32(attr);
828 break;
829 }
830 }
831
832 if (cfg->fc_nh_id) {
833 if (cfg->fc_oif || cfg->fc_gw_family ||
834 cfg->fc_encap || cfg->fc_mp) {
835 NL_SET_ERR_MSG(extack,
836 "Nexthop specification and nexthop id are mutually exclusive");
837 return -EINVAL;
838 }
839 }
840
841 if (has_gw && has_via) {
842 NL_SET_ERR_MSG(extack,
843 "Nexthop configuration can not contain both GATEWAY and VIA");
844 return -EINVAL;
845 }
846
847 if (!cfg->fc_table)
848 cfg->fc_table = RT_TABLE_MAIN;
849
850 return 0;
851 errout:
852 return err;
853 }
854
inet_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)855 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
856 struct netlink_ext_ack *extack)
857 {
858 struct net *net = sock_net(skb->sk);
859 struct fib_config cfg;
860 struct fib_table *tb;
861 int err;
862
863 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
864 if (err < 0)
865 goto errout;
866
867 if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
868 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
869 err = -EINVAL;
870 goto errout;
871 }
872
873 tb = fib_get_table(net, cfg.fc_table);
874 if (!tb) {
875 NL_SET_ERR_MSG(extack, "FIB table does not exist");
876 err = -ESRCH;
877 goto errout;
878 }
879
880 err = fib_table_delete(net, tb, &cfg, extack);
881 errout:
882 return err;
883 }
884
inet_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)885 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
886 struct netlink_ext_ack *extack)
887 {
888 struct net *net = sock_net(skb->sk);
889 struct fib_config cfg;
890 struct fib_table *tb;
891 int err;
892
893 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
894 if (err < 0)
895 goto errout;
896
897 tb = fib_new_table(net, cfg.fc_table);
898 if (!tb) {
899 err = -ENOBUFS;
900 goto errout;
901 }
902
903 err = fib_table_insert(net, tb, &cfg, extack);
904 if (!err && cfg.fc_type == RTN_LOCAL)
905 net->ipv4.fib_has_custom_local_routes = true;
906 errout:
907 return err;
908 }
909
ip_valid_fib_dump_req(struct net * net,const struct nlmsghdr * nlh,struct fib_dump_filter * filter,struct netlink_callback * cb)910 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
911 struct fib_dump_filter *filter,
912 struct netlink_callback *cb)
913 {
914 struct netlink_ext_ack *extack = cb->extack;
915 struct nlattr *tb[RTA_MAX + 1];
916 struct rtmsg *rtm;
917 int err, i;
918
919 if (filter->rtnl_held)
920 ASSERT_RTNL();
921
922 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
923 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
924 return -EINVAL;
925 }
926
927 rtm = nlmsg_data(nlh);
928 if (rtm->rtm_dst_len || rtm->rtm_src_len || rtm->rtm_tos ||
929 rtm->rtm_scope) {
930 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
931 return -EINVAL;
932 }
933
934 if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
935 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
936 return -EINVAL;
937 }
938 if (rtm->rtm_flags & RTM_F_CLONED)
939 filter->dump_routes = false;
940 else
941 filter->dump_exceptions = false;
942
943 filter->flags = rtm->rtm_flags;
944 filter->protocol = rtm->rtm_protocol;
945 filter->rt_type = rtm->rtm_type;
946 filter->table_id = rtm->rtm_table;
947
948 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
949 rtm_ipv4_policy, extack);
950 if (err < 0)
951 return err;
952
953 for (i = 0; i <= RTA_MAX; ++i) {
954 int ifindex;
955
956 if (!tb[i])
957 continue;
958
959 switch (i) {
960 case RTA_TABLE:
961 filter->table_id = nla_get_u32(tb[i]);
962 break;
963 case RTA_OIF:
964 ifindex = nla_get_u32(tb[i]);
965 if (filter->rtnl_held)
966 filter->dev = __dev_get_by_index(net, ifindex);
967 else
968 filter->dev = dev_get_by_index_rcu(net, ifindex);
969 if (!filter->dev)
970 return -ENODEV;
971 break;
972 default:
973 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
974 return -EINVAL;
975 }
976 }
977
978 if (filter->flags || filter->protocol || filter->rt_type ||
979 filter->table_id || filter->dev) {
980 filter->filter_set = 1;
981 cb->answer_flags = NLM_F_DUMP_FILTERED;
982 }
983
984 return 0;
985 }
986 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
987
inet_dump_fib(struct sk_buff * skb,struct netlink_callback * cb)988 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
989 {
990 struct fib_dump_filter filter = {
991 .dump_routes = true,
992 .dump_exceptions = true,
993 .rtnl_held = false,
994 };
995 const struct nlmsghdr *nlh = cb->nlh;
996 struct net *net = sock_net(skb->sk);
997 unsigned int h, s_h;
998 unsigned int e = 0, s_e;
999 struct fib_table *tb;
1000 struct hlist_head *head;
1001 int dumped = 0, err = 0;
1002
1003 rcu_read_lock();
1004 if (cb->strict_check) {
1005 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
1006 if (err < 0)
1007 goto unlock;
1008 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
1009 struct rtmsg *rtm = nlmsg_data(nlh);
1010
1011 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
1012 }
1013
1014 /* ipv4 does not use prefix flag */
1015 if (filter.flags & RTM_F_PREFIX)
1016 goto unlock;
1017
1018 if (filter.table_id) {
1019 tb = fib_get_table(net, filter.table_id);
1020 if (!tb) {
1021 if (rtnl_msg_family(cb->nlh) != PF_INET)
1022 goto unlock;
1023
1024 NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1025 err = -ENOENT;
1026 goto unlock;
1027 }
1028 err = fib_table_dump(tb, skb, cb, &filter);
1029 goto unlock;
1030 }
1031
1032 s_h = cb->args[0];
1033 s_e = cb->args[1];
1034
1035 err = 0;
1036 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1037 e = 0;
1038 head = &net->ipv4.fib_table_hash[h];
1039 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1040 if (e < s_e)
1041 goto next;
1042 if (dumped)
1043 memset(&cb->args[2], 0, sizeof(cb->args) -
1044 2 * sizeof(cb->args[0]));
1045 err = fib_table_dump(tb, skb, cb, &filter);
1046 if (err < 0)
1047 goto out;
1048 dumped = 1;
1049 next:
1050 e++;
1051 }
1052 }
1053 out:
1054
1055 cb->args[1] = e;
1056 cb->args[0] = h;
1057
1058 unlock:
1059 rcu_read_unlock();
1060 return err;
1061 }
1062
1063 /* Prepare and feed intra-kernel routing request.
1064 * Really, it should be netlink message, but :-( netlink
1065 * can be not configured, so that we feed it directly
1066 * to fib engine. It is legal, because all events occur
1067 * only when netlink is already locked.
1068 */
fib_magic(int cmd,int type,__be32 dst,int dst_len,struct in_ifaddr * ifa,u32 rt_priority)1069 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1070 struct in_ifaddr *ifa, u32 rt_priority)
1071 {
1072 struct net *net = dev_net(ifa->ifa_dev->dev);
1073 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1074 struct fib_table *tb;
1075 struct fib_config cfg = {
1076 .fc_protocol = RTPROT_KERNEL,
1077 .fc_type = type,
1078 .fc_dst = dst,
1079 .fc_dst_len = dst_len,
1080 .fc_priority = rt_priority,
1081 .fc_prefsrc = ifa->ifa_local,
1082 .fc_oif = ifa->ifa_dev->dev->ifindex,
1083 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1084 .fc_nlinfo = {
1085 .nl_net = net,
1086 },
1087 };
1088
1089 if (!tb_id)
1090 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1091
1092 tb = fib_new_table(net, tb_id);
1093 if (!tb)
1094 return;
1095
1096 cfg.fc_table = tb->tb_id;
1097
1098 if (type != RTN_LOCAL)
1099 cfg.fc_scope = RT_SCOPE_LINK;
1100 else
1101 cfg.fc_scope = RT_SCOPE_HOST;
1102
1103 if (cmd == RTM_NEWROUTE)
1104 fib_table_insert(net, tb, &cfg, NULL);
1105 else
1106 fib_table_delete(net, tb, &cfg, NULL);
1107 }
1108
fib_add_ifaddr(struct in_ifaddr * ifa)1109 void fib_add_ifaddr(struct in_ifaddr *ifa)
1110 {
1111 struct in_device *in_dev = ifa->ifa_dev;
1112 struct net_device *dev = in_dev->dev;
1113 struct in_ifaddr *prim = ifa;
1114 __be32 mask = ifa->ifa_mask;
1115 __be32 addr = ifa->ifa_local;
1116 __be32 prefix = ifa->ifa_address & mask;
1117
1118 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1119 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1120 if (!prim) {
1121 pr_warn("%s: bug: prim == NULL\n", __func__);
1122 return;
1123 }
1124 }
1125
1126 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1127
1128 if (!(dev->flags & IFF_UP))
1129 return;
1130
1131 /* Add broadcast address, if it is explicitly assigned. */
1132 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) {
1133 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1134 prim, 0);
1135 arp_invalidate(dev, ifa->ifa_broadcast, false);
1136 }
1137
1138 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1139 (prefix != addr || ifa->ifa_prefixlen < 32)) {
1140 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1141 fib_magic(RTM_NEWROUTE,
1142 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1143 prefix, ifa->ifa_prefixlen, prim,
1144 ifa->ifa_rt_priority);
1145
1146 /* Add the network broadcast address, when it makes sense */
1147 if (ifa->ifa_prefixlen < 31) {
1148 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1149 32, prim, 0);
1150 arp_invalidate(dev, prefix | ~mask, false);
1151 }
1152 }
1153 }
1154
fib_modify_prefix_metric(struct in_ifaddr * ifa,u32 new_metric)1155 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1156 {
1157 __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1158 struct in_device *in_dev = ifa->ifa_dev;
1159 struct net_device *dev = in_dev->dev;
1160
1161 if (!(dev->flags & IFF_UP) ||
1162 ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1163 ipv4_is_zeronet(prefix) ||
1164 (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1165 return;
1166
1167 /* add the new */
1168 fib_magic(RTM_NEWROUTE,
1169 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1170 prefix, ifa->ifa_prefixlen, ifa, new_metric);
1171
1172 /* delete the old */
1173 fib_magic(RTM_DELROUTE,
1174 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1175 prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1176 }
1177
1178 /* Delete primary or secondary address.
1179 * Optionally, on secondary address promotion consider the addresses
1180 * from subnet iprim as deleted, even if they are in device list.
1181 * In this case the secondary ifa can be in device list.
1182 */
fib_del_ifaddr(struct in_ifaddr * ifa,struct in_ifaddr * iprim)1183 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1184 {
1185 struct in_device *in_dev = ifa->ifa_dev;
1186 struct net_device *dev = in_dev->dev;
1187 struct in_ifaddr *ifa1;
1188 struct in_ifaddr *prim = ifa, *prim1 = NULL;
1189 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1190 __be32 any = ifa->ifa_address & ifa->ifa_mask;
1191 #define LOCAL_OK 1
1192 #define BRD_OK 2
1193 #define BRD0_OK 4
1194 #define BRD1_OK 8
1195 unsigned int ok = 0;
1196 int subnet = 0; /* Primary network */
1197 int gone = 1; /* Address is missing */
1198 int same_prefsrc = 0; /* Another primary with same IP */
1199
1200 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1201 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1202 if (!prim) {
1203 /* if the device has been deleted, we don't perform
1204 * address promotion
1205 */
1206 if (!in_dev->dead)
1207 pr_warn("%s: bug: prim == NULL\n", __func__);
1208 return;
1209 }
1210 if (iprim && iprim != prim) {
1211 pr_warn("%s: bug: iprim != prim\n", __func__);
1212 return;
1213 }
1214 } else if (!ipv4_is_zeronet(any) &&
1215 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1216 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1217 fib_magic(RTM_DELROUTE,
1218 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1219 any, ifa->ifa_prefixlen, prim, 0);
1220 subnet = 1;
1221 }
1222
1223 if (in_dev->dead)
1224 goto no_promotions;
1225
1226 /* Deletion is more complicated than add.
1227 * We should take care of not to delete too much :-)
1228 *
1229 * Scan address list to be sure that addresses are really gone.
1230 */
1231 rcu_read_lock();
1232 in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1233 if (ifa1 == ifa) {
1234 /* promotion, keep the IP */
1235 gone = 0;
1236 continue;
1237 }
1238 /* Ignore IFAs from our subnet */
1239 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1240 inet_ifa_match(ifa1->ifa_address, iprim))
1241 continue;
1242
1243 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1244 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1245 /* Another address from our subnet? */
1246 if (ifa1->ifa_mask == prim->ifa_mask &&
1247 inet_ifa_match(ifa1->ifa_address, prim))
1248 prim1 = prim;
1249 else {
1250 /* We reached the secondaries, so
1251 * same_prefsrc should be determined.
1252 */
1253 if (!same_prefsrc)
1254 continue;
1255 /* Search new prim1 if ifa1 is not
1256 * using the current prim1
1257 */
1258 if (!prim1 ||
1259 ifa1->ifa_mask != prim1->ifa_mask ||
1260 !inet_ifa_match(ifa1->ifa_address, prim1))
1261 prim1 = inet_ifa_byprefix(in_dev,
1262 ifa1->ifa_address,
1263 ifa1->ifa_mask);
1264 if (!prim1)
1265 continue;
1266 if (prim1->ifa_local != prim->ifa_local)
1267 continue;
1268 }
1269 } else {
1270 if (prim->ifa_local != ifa1->ifa_local)
1271 continue;
1272 prim1 = ifa1;
1273 if (prim != prim1)
1274 same_prefsrc = 1;
1275 }
1276 if (ifa->ifa_local == ifa1->ifa_local)
1277 ok |= LOCAL_OK;
1278 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1279 ok |= BRD_OK;
1280 if (brd == ifa1->ifa_broadcast)
1281 ok |= BRD1_OK;
1282 if (any == ifa1->ifa_broadcast)
1283 ok |= BRD0_OK;
1284 /* primary has network specific broadcasts */
1285 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1286 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1287 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1288
1289 if (!ipv4_is_zeronet(any1)) {
1290 if (ifa->ifa_broadcast == brd1 ||
1291 ifa->ifa_broadcast == any1)
1292 ok |= BRD_OK;
1293 if (brd == brd1 || brd == any1)
1294 ok |= BRD1_OK;
1295 if (any == brd1 || any == any1)
1296 ok |= BRD0_OK;
1297 }
1298 }
1299 }
1300 rcu_read_unlock();
1301
1302 no_promotions:
1303 if (!(ok & BRD_OK))
1304 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1305 prim, 0);
1306 if (subnet && ifa->ifa_prefixlen < 31) {
1307 if (!(ok & BRD1_OK))
1308 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1309 prim, 0);
1310 if (!(ok & BRD0_OK))
1311 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1312 prim, 0);
1313 }
1314 if (!(ok & LOCAL_OK)) {
1315 unsigned int addr_type;
1316
1317 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1318
1319 /* Check, that this local address finally disappeared. */
1320 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1321 ifa->ifa_local);
1322 if (gone && addr_type != RTN_LOCAL) {
1323 /* And the last, but not the least thing.
1324 * We must flush stray FIB entries.
1325 *
1326 * First of all, we scan fib_info list searching
1327 * for stray nexthop entries, then ignite fib_flush.
1328 */
1329 if (fib_sync_down_addr(dev, ifa->ifa_local))
1330 fib_flush(dev_net(dev));
1331 }
1332 }
1333 #undef LOCAL_OK
1334 #undef BRD_OK
1335 #undef BRD0_OK
1336 #undef BRD1_OK
1337 }
1338
nl_fib_lookup(struct net * net,struct fib_result_nl * frn)1339 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1340 {
1341
1342 struct fib_result res;
1343 struct flowi4 fl4 = {
1344 .flowi4_mark = frn->fl_mark,
1345 .daddr = frn->fl_addr,
1346 .flowi4_tos = frn->fl_tos,
1347 .flowi4_scope = frn->fl_scope,
1348 };
1349 struct fib_table *tb;
1350
1351 rcu_read_lock();
1352
1353 tb = fib_get_table(net, frn->tb_id_in);
1354
1355 frn->err = -ENOENT;
1356 if (tb) {
1357 local_bh_disable();
1358
1359 frn->tb_id = tb->tb_id;
1360 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1361
1362 if (!frn->err) {
1363 frn->prefixlen = res.prefixlen;
1364 frn->nh_sel = res.nh_sel;
1365 frn->type = res.type;
1366 frn->scope = res.scope;
1367 }
1368 local_bh_enable();
1369 }
1370
1371 rcu_read_unlock();
1372 }
1373
nl_fib_input(struct sk_buff * skb)1374 static void nl_fib_input(struct sk_buff *skb)
1375 {
1376 struct net *net;
1377 struct fib_result_nl *frn;
1378 struct nlmsghdr *nlh;
1379 u32 portid;
1380
1381 net = sock_net(skb->sk);
1382 nlh = nlmsg_hdr(skb);
1383 if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1384 skb->len < nlh->nlmsg_len ||
1385 nlmsg_len(nlh) < sizeof(*frn))
1386 return;
1387
1388 skb = netlink_skb_clone(skb, GFP_KERNEL);
1389 if (!skb)
1390 return;
1391 nlh = nlmsg_hdr(skb);
1392
1393 frn = nlmsg_data(nlh);
1394 nl_fib_lookup(net, frn);
1395
1396 portid = NETLINK_CB(skb).portid; /* netlink portid */
1397 NETLINK_CB(skb).portid = 0; /* from kernel */
1398 NETLINK_CB(skb).dst_group = 0; /* unicast */
1399 nlmsg_unicast(net->ipv4.fibnl, skb, portid);
1400 }
1401
nl_fib_lookup_init(struct net * net)1402 static int __net_init nl_fib_lookup_init(struct net *net)
1403 {
1404 struct sock *sk;
1405 struct netlink_kernel_cfg cfg = {
1406 .input = nl_fib_input,
1407 };
1408
1409 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1410 if (!sk)
1411 return -EAFNOSUPPORT;
1412 net->ipv4.fibnl = sk;
1413 return 0;
1414 }
1415
nl_fib_lookup_exit(struct net * net)1416 static void nl_fib_lookup_exit(struct net *net)
1417 {
1418 netlink_kernel_release(net->ipv4.fibnl);
1419 net->ipv4.fibnl = NULL;
1420 }
1421
fib_disable_ip(struct net_device * dev,unsigned long event,bool force)1422 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1423 bool force)
1424 {
1425 if (fib_sync_down_dev(dev, event, force))
1426 fib_flush(dev_net(dev));
1427 else
1428 rt_cache_flush(dev_net(dev));
1429 arp_ifdown(dev);
1430 }
1431
fib_inetaddr_event(struct notifier_block * this,unsigned long event,void * ptr)1432 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1433 {
1434 struct in_ifaddr *ifa = ptr;
1435 struct net_device *dev = ifa->ifa_dev->dev;
1436 struct net *net = dev_net(dev);
1437
1438 switch (event) {
1439 case NETDEV_UP:
1440 fib_add_ifaddr(ifa);
1441 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1442 fib_sync_up(dev, RTNH_F_DEAD);
1443 #endif
1444 atomic_inc(&net->ipv4.dev_addr_genid);
1445 rt_cache_flush(dev_net(dev));
1446 break;
1447 case NETDEV_DOWN:
1448 fib_del_ifaddr(ifa, NULL);
1449 atomic_inc(&net->ipv4.dev_addr_genid);
1450 if (!ifa->ifa_dev->ifa_list) {
1451 /* Last address was deleted from this interface.
1452 * Disable IP.
1453 */
1454 fib_disable_ip(dev, event, true);
1455 } else {
1456 rt_cache_flush(dev_net(dev));
1457 }
1458 break;
1459 }
1460 return NOTIFY_DONE;
1461 }
1462
fib_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1463 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1464 {
1465 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1466 struct netdev_notifier_changeupper_info *upper_info = ptr;
1467 struct netdev_notifier_info_ext *info_ext = ptr;
1468 struct in_device *in_dev;
1469 struct net *net = dev_net(dev);
1470 struct in_ifaddr *ifa;
1471 unsigned int flags;
1472
1473 if (event == NETDEV_UNREGISTER) {
1474 fib_disable_ip(dev, event, true);
1475 rt_flush_dev(dev);
1476 return NOTIFY_DONE;
1477 }
1478
1479 in_dev = __in_dev_get_rtnl(dev);
1480 if (!in_dev)
1481 return NOTIFY_DONE;
1482
1483 switch (event) {
1484 case NETDEV_UP:
1485 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1486 fib_add_ifaddr(ifa);
1487 }
1488 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1489 fib_sync_up(dev, RTNH_F_DEAD);
1490 #endif
1491 atomic_inc(&net->ipv4.dev_addr_genid);
1492 rt_cache_flush(net);
1493 break;
1494 case NETDEV_DOWN:
1495 fib_disable_ip(dev, event, false);
1496 break;
1497 case NETDEV_CHANGE:
1498 flags = dev_get_flags(dev);
1499 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1500 fib_sync_up(dev, RTNH_F_LINKDOWN);
1501 else
1502 fib_sync_down_dev(dev, event, false);
1503 rt_cache_flush(net);
1504 break;
1505 case NETDEV_CHANGEMTU:
1506 fib_sync_mtu(dev, info_ext->ext.mtu);
1507 rt_cache_flush(net);
1508 break;
1509 case NETDEV_CHANGEUPPER:
1510 upper_info = ptr;
1511 /* flush all routes if dev is linked to or unlinked from
1512 * an L3 master device (e.g., VRF)
1513 */
1514 if (upper_info->upper_dev &&
1515 netif_is_l3_master(upper_info->upper_dev))
1516 fib_disable_ip(dev, NETDEV_DOWN, true);
1517 break;
1518 }
1519 return NOTIFY_DONE;
1520 }
1521
1522 static struct notifier_block fib_inetaddr_notifier = {
1523 .notifier_call = fib_inetaddr_event,
1524 };
1525
1526 static struct notifier_block fib_netdev_notifier = {
1527 .notifier_call = fib_netdev_event,
1528 };
1529
ip_fib_net_init(struct net * net)1530 static int __net_init ip_fib_net_init(struct net *net)
1531 {
1532 int err;
1533 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1534
1535 err = fib4_notifier_init(net);
1536 if (err)
1537 return err;
1538
1539 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1540 /* Default to 3-tuple */
1541 net->ipv4.sysctl_fib_multipath_hash_fields =
1542 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
1543 #endif
1544
1545 /* Avoid false sharing : Use at least a full cache line */
1546 size = max_t(size_t, size, L1_CACHE_BYTES);
1547
1548 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1549 if (!net->ipv4.fib_table_hash) {
1550 err = -ENOMEM;
1551 goto err_table_hash_alloc;
1552 }
1553
1554 err = fib4_rules_init(net);
1555 if (err < 0)
1556 goto err_rules_init;
1557 return 0;
1558
1559 err_rules_init:
1560 kfree(net->ipv4.fib_table_hash);
1561 err_table_hash_alloc:
1562 fib4_notifier_exit(net);
1563 return err;
1564 }
1565
ip_fib_net_exit(struct net * net)1566 static void ip_fib_net_exit(struct net *net)
1567 {
1568 int i;
1569
1570 ASSERT_RTNL();
1571 #ifdef CONFIG_IP_MULTIPLE_TABLES
1572 RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1573 RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1574 #endif
1575 /* Destroy the tables in reverse order to guarantee that the
1576 * local table, ID 255, is destroyed before the main table, ID
1577 * 254. This is necessary as the local table may contain
1578 * references to data contained in the main table.
1579 */
1580 for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1581 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1582 struct hlist_node *tmp;
1583 struct fib_table *tb;
1584
1585 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1586 hlist_del(&tb->tb_hlist);
1587 fib_table_flush(net, tb, true);
1588 fib_free_table(tb);
1589 }
1590 }
1591
1592 #ifdef CONFIG_IP_MULTIPLE_TABLES
1593 fib4_rules_exit(net);
1594 #endif
1595
1596 kfree(net->ipv4.fib_table_hash);
1597 fib4_notifier_exit(net);
1598 }
1599
fib_net_init(struct net * net)1600 static int __net_init fib_net_init(struct net *net)
1601 {
1602 int error;
1603
1604 #ifdef CONFIG_IP_ROUTE_CLASSID
1605 atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
1606 #endif
1607 error = ip_fib_net_init(net);
1608 if (error < 0)
1609 goto out;
1610 error = nl_fib_lookup_init(net);
1611 if (error < 0)
1612 goto out_nlfl;
1613 error = fib_proc_init(net);
1614 if (error < 0)
1615 goto out_proc;
1616 out:
1617 return error;
1618
1619 out_proc:
1620 nl_fib_lookup_exit(net);
1621 out_nlfl:
1622 rtnl_lock();
1623 ip_fib_net_exit(net);
1624 rtnl_unlock();
1625 goto out;
1626 }
1627
fib_net_exit(struct net * net)1628 static void __net_exit fib_net_exit(struct net *net)
1629 {
1630 fib_proc_exit(net);
1631 nl_fib_lookup_exit(net);
1632 }
1633
fib_net_exit_batch(struct list_head * net_list)1634 static void __net_exit fib_net_exit_batch(struct list_head *net_list)
1635 {
1636 struct net *net;
1637
1638 rtnl_lock();
1639 list_for_each_entry(net, net_list, exit_list)
1640 ip_fib_net_exit(net);
1641
1642 rtnl_unlock();
1643 }
1644
1645 static struct pernet_operations fib_net_ops = {
1646 .init = fib_net_init,
1647 .exit = fib_net_exit,
1648 .exit_batch = fib_net_exit_batch,
1649 };
1650
ip_fib_init(void)1651 void __init ip_fib_init(void)
1652 {
1653 fib_trie_init();
1654
1655 register_pernet_subsys(&fib_net_ops);
1656
1657 register_netdevice_notifier(&fib_netdev_notifier);
1658 register_inetaddr_notifier(&fib_inetaddr_notifier);
1659
1660 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1661 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1662 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib,
1663 RTNL_FLAG_DUMP_UNLOCKED | RTNL_FLAG_DUMP_SPLIT_NLM_DONE);
1664 }
1665