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_LINK;
393 return ret;
394 }
395 if (no_addr)
396 goto last_resort;
397 if (rpf == 1)
398 goto e_rpf;
399 fl4.flowi4_oif = dev->ifindex;
400
401 ret = 0;
402 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
403 if (res.type == RTN_UNICAST)
404 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_LINK;
405 }
406 return ret;
407
408 last_resort:
409 if (rpf)
410 goto e_rpf;
411 *itag = 0;
412 return 0;
413
414 e_inval:
415 return -EINVAL;
416 e_rpf:
417 return -EXDEV;
418 }
419
420 /* Ignore rp_filter for packets protected by IPsec. */
fib_validate_source(struct sk_buff * skb,__be32 src,__be32 dst,u8 tos,int oif,struct net_device * dev,struct in_device * idev,u32 * itag)421 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
422 u8 tos, int oif, struct net_device *dev,
423 struct in_device *idev, u32 *itag)
424 {
425 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
426 struct net *net = dev_net(dev);
427
428 if (!r && !fib_num_tclassid_users(net) &&
429 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
430 if (IN_DEV_ACCEPT_LOCAL(idev))
431 goto ok;
432 /* with custom local routes in place, checking local addresses
433 * only will be too optimistic, with custom rules, checking
434 * local addresses only can be too strict, e.g. due to vrf
435 */
436 if (net->ipv4.fib_has_custom_local_routes ||
437 fib4_has_custom_rules(net))
438 goto full_check;
439 /* 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 (cmd == SIOCDELRT)
580 return 0;
581
582 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
583 return -EINVAL;
584
585 if (cfg->fc_scope == RT_SCOPE_NOWHERE)
586 cfg->fc_scope = RT_SCOPE_LINK;
587
588 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
589 struct nlattr *mx;
590 int len = 0;
591
592 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
593 if (!mx)
594 return -ENOMEM;
595
596 if (rt->rt_flags & RTF_MTU)
597 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
598
599 if (rt->rt_flags & RTF_WINDOW)
600 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
601
602 if (rt->rt_flags & RTF_IRTT)
603 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
604
605 cfg->fc_mx = mx;
606 cfg->fc_mx_len = len;
607 }
608
609 return 0;
610 }
611
612 /*
613 * Handle IP routing ioctl calls.
614 * These are used to manipulate the routing tables
615 */
ip_rt_ioctl(struct net * net,unsigned int cmd,struct rtentry * rt)616 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
617 {
618 struct fib_config cfg;
619 int err;
620
621 switch (cmd) {
622 case SIOCADDRT: /* Add a route */
623 case SIOCDELRT: /* Delete a route */
624 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
625 return -EPERM;
626
627 rtnl_lock();
628 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
629 if (err == 0) {
630 struct fib_table *tb;
631
632 if (cmd == SIOCDELRT) {
633 tb = fib_get_table(net, cfg.fc_table);
634 if (tb)
635 err = fib_table_delete(net, tb, &cfg,
636 NULL);
637 else
638 err = -ESRCH;
639 } else {
640 tb = fib_new_table(net, cfg.fc_table);
641 if (tb)
642 err = fib_table_insert(net, tb,
643 &cfg, NULL);
644 else
645 err = -ENOBUFS;
646 }
647
648 /* allocated by rtentry_to_fib_config() */
649 kfree(cfg.fc_mx);
650 }
651 rtnl_unlock();
652 return err;
653 }
654 return -EINVAL;
655 }
656
657 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
658 [RTA_UNSPEC] = { .strict_start_type = RTA_DPORT + 1 },
659 [RTA_DST] = { .type = NLA_U32 },
660 [RTA_SRC] = { .type = NLA_U32 },
661 [RTA_IIF] = { .type = NLA_U32 },
662 [RTA_OIF] = { .type = NLA_U32 },
663 [RTA_GATEWAY] = { .type = NLA_U32 },
664 [RTA_PRIORITY] = { .type = NLA_U32 },
665 [RTA_PREFSRC] = { .type = NLA_U32 },
666 [RTA_METRICS] = { .type = NLA_NESTED },
667 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
668 [RTA_FLOW] = { .type = NLA_U32 },
669 [RTA_ENCAP_TYPE] = { .type = NLA_U16 },
670 [RTA_ENCAP] = { .type = NLA_NESTED },
671 [RTA_UID] = { .type = NLA_U32 },
672 [RTA_MARK] = { .type = NLA_U32 },
673 [RTA_TABLE] = { .type = NLA_U32 },
674 [RTA_IP_PROTO] = { .type = NLA_U8 },
675 [RTA_SPORT] = { .type = NLA_U16 },
676 [RTA_DPORT] = { .type = NLA_U16 },
677 [RTA_NH_ID] = { .type = NLA_U32 },
678 };
679
fib_gw_from_via(struct fib_config * cfg,struct nlattr * nla,struct netlink_ext_ack * extack)680 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
681 struct netlink_ext_ack *extack)
682 {
683 struct rtvia *via;
684 int alen;
685
686 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
687 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
688 return -EINVAL;
689 }
690
691 via = nla_data(nla);
692 alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
693
694 switch (via->rtvia_family) {
695 case AF_INET:
696 if (alen != sizeof(__be32)) {
697 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
698 return -EINVAL;
699 }
700 cfg->fc_gw_family = AF_INET;
701 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
702 break;
703 case AF_INET6:
704 #if IS_ENABLED(CONFIG_IPV6)
705 if (alen != sizeof(struct in6_addr)) {
706 NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
707 return -EINVAL;
708 }
709 cfg->fc_gw_family = AF_INET6;
710 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
711 #else
712 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
713 return -EINVAL;
714 #endif
715 break;
716 default:
717 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
718 return -EINVAL;
719 }
720
721 return 0;
722 }
723
rtm_to_fib_config(struct net * net,struct sk_buff * skb,struct nlmsghdr * nlh,struct fib_config * cfg,struct netlink_ext_ack * extack)724 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
725 struct nlmsghdr *nlh, struct fib_config *cfg,
726 struct netlink_ext_ack *extack)
727 {
728 bool has_gw = false, has_via = false;
729 struct nlattr *attr;
730 int err, remaining;
731 struct rtmsg *rtm;
732
733 err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
734 rtm_ipv4_policy, extack);
735 if (err < 0)
736 goto errout;
737
738 memset(cfg, 0, sizeof(*cfg));
739
740 rtm = nlmsg_data(nlh);
741
742 if (!inet_validate_dscp(rtm->rtm_tos)) {
743 NL_SET_ERR_MSG(extack,
744 "Invalid dsfield (tos): ECN bits must be 0");
745 err = -EINVAL;
746 goto errout;
747 }
748 cfg->fc_dscp = inet_dsfield_to_dscp(rtm->rtm_tos);
749
750 cfg->fc_dst_len = rtm->rtm_dst_len;
751 cfg->fc_table = rtm->rtm_table;
752 cfg->fc_protocol = rtm->rtm_protocol;
753 cfg->fc_scope = rtm->rtm_scope;
754 cfg->fc_type = rtm->rtm_type;
755 cfg->fc_flags = rtm->rtm_flags;
756 cfg->fc_nlflags = nlh->nlmsg_flags;
757
758 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
759 cfg->fc_nlinfo.nlh = nlh;
760 cfg->fc_nlinfo.nl_net = net;
761
762 if (cfg->fc_type > RTN_MAX) {
763 NL_SET_ERR_MSG(extack, "Invalid route type");
764 err = -EINVAL;
765 goto errout;
766 }
767
768 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
769 switch (nla_type(attr)) {
770 case RTA_DST:
771 cfg->fc_dst = nla_get_be32(attr);
772 break;
773 case RTA_OIF:
774 cfg->fc_oif = nla_get_u32(attr);
775 break;
776 case RTA_GATEWAY:
777 has_gw = true;
778 cfg->fc_gw4 = nla_get_be32(attr);
779 if (cfg->fc_gw4)
780 cfg->fc_gw_family = AF_INET;
781 break;
782 case RTA_VIA:
783 has_via = true;
784 err = fib_gw_from_via(cfg, attr, extack);
785 if (err)
786 goto errout;
787 break;
788 case RTA_PRIORITY:
789 cfg->fc_priority = nla_get_u32(attr);
790 break;
791 case RTA_PREFSRC:
792 cfg->fc_prefsrc = nla_get_be32(attr);
793 break;
794 case RTA_METRICS:
795 cfg->fc_mx = nla_data(attr);
796 cfg->fc_mx_len = nla_len(attr);
797 break;
798 case RTA_MULTIPATH:
799 err = lwtunnel_valid_encap_type_attr(nla_data(attr),
800 nla_len(attr),
801 extack);
802 if (err < 0)
803 goto errout;
804 cfg->fc_mp = nla_data(attr);
805 cfg->fc_mp_len = nla_len(attr);
806 break;
807 case RTA_FLOW:
808 cfg->fc_flow = nla_get_u32(attr);
809 break;
810 case RTA_TABLE:
811 cfg->fc_table = nla_get_u32(attr);
812 break;
813 case RTA_ENCAP:
814 cfg->fc_encap = attr;
815 break;
816 case RTA_ENCAP_TYPE:
817 cfg->fc_encap_type = nla_get_u16(attr);
818 err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
819 extack);
820 if (err < 0)
821 goto errout;
822 break;
823 case RTA_NH_ID:
824 cfg->fc_nh_id = nla_get_u32(attr);
825 break;
826 }
827 }
828
829 if (cfg->fc_nh_id) {
830 if (cfg->fc_oif || cfg->fc_gw_family ||
831 cfg->fc_encap || cfg->fc_mp) {
832 NL_SET_ERR_MSG(extack,
833 "Nexthop specification and nexthop id are mutually exclusive");
834 return -EINVAL;
835 }
836 }
837
838 if (has_gw && has_via) {
839 NL_SET_ERR_MSG(extack,
840 "Nexthop configuration can not contain both GATEWAY and VIA");
841 return -EINVAL;
842 }
843
844 return 0;
845 errout:
846 return err;
847 }
848
inet_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)849 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
850 struct netlink_ext_ack *extack)
851 {
852 struct net *net = sock_net(skb->sk);
853 struct fib_config cfg;
854 struct fib_table *tb;
855 int err;
856
857 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
858 if (err < 0)
859 goto errout;
860
861 if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
862 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
863 err = -EINVAL;
864 goto errout;
865 }
866
867 tb = fib_get_table(net, cfg.fc_table);
868 if (!tb) {
869 NL_SET_ERR_MSG(extack, "FIB table does not exist");
870 err = -ESRCH;
871 goto errout;
872 }
873
874 err = fib_table_delete(net, tb, &cfg, extack);
875 errout:
876 return err;
877 }
878
inet_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)879 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
880 struct netlink_ext_ack *extack)
881 {
882 struct net *net = sock_net(skb->sk);
883 struct fib_config cfg;
884 struct fib_table *tb;
885 int err;
886
887 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
888 if (err < 0)
889 goto errout;
890
891 tb = fib_new_table(net, cfg.fc_table);
892 if (!tb) {
893 err = -ENOBUFS;
894 goto errout;
895 }
896
897 err = fib_table_insert(net, tb, &cfg, extack);
898 if (!err && cfg.fc_type == RTN_LOCAL)
899 net->ipv4.fib_has_custom_local_routes = true;
900 errout:
901 return err;
902 }
903
ip_valid_fib_dump_req(struct net * net,const struct nlmsghdr * nlh,struct fib_dump_filter * filter,struct netlink_callback * cb)904 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
905 struct fib_dump_filter *filter,
906 struct netlink_callback *cb)
907 {
908 struct netlink_ext_ack *extack = cb->extack;
909 struct nlattr *tb[RTA_MAX + 1];
910 struct rtmsg *rtm;
911 int err, i;
912
913 ASSERT_RTNL();
914
915 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
916 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
917 return -EINVAL;
918 }
919
920 rtm = nlmsg_data(nlh);
921 if (rtm->rtm_dst_len || rtm->rtm_src_len || rtm->rtm_tos ||
922 rtm->rtm_scope) {
923 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
924 return -EINVAL;
925 }
926
927 if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
928 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
929 return -EINVAL;
930 }
931 if (rtm->rtm_flags & RTM_F_CLONED)
932 filter->dump_routes = false;
933 else
934 filter->dump_exceptions = false;
935
936 filter->flags = rtm->rtm_flags;
937 filter->protocol = rtm->rtm_protocol;
938 filter->rt_type = rtm->rtm_type;
939 filter->table_id = rtm->rtm_table;
940
941 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
942 rtm_ipv4_policy, extack);
943 if (err < 0)
944 return err;
945
946 for (i = 0; i <= RTA_MAX; ++i) {
947 int ifindex;
948
949 if (!tb[i])
950 continue;
951
952 switch (i) {
953 case RTA_TABLE:
954 filter->table_id = nla_get_u32(tb[i]);
955 break;
956 case RTA_OIF:
957 ifindex = nla_get_u32(tb[i]);
958 filter->dev = __dev_get_by_index(net, ifindex);
959 if (!filter->dev)
960 return -ENODEV;
961 break;
962 default:
963 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
964 return -EINVAL;
965 }
966 }
967
968 if (filter->flags || filter->protocol || filter->rt_type ||
969 filter->table_id || filter->dev) {
970 filter->filter_set = 1;
971 cb->answer_flags = NLM_F_DUMP_FILTERED;
972 }
973
974 return 0;
975 }
976 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
977
inet_dump_fib(struct sk_buff * skb,struct netlink_callback * cb)978 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
979 {
980 struct fib_dump_filter filter = { .dump_routes = true,
981 .dump_exceptions = true };
982 const struct nlmsghdr *nlh = cb->nlh;
983 struct net *net = sock_net(skb->sk);
984 unsigned int h, s_h;
985 unsigned int e = 0, s_e;
986 struct fib_table *tb;
987 struct hlist_head *head;
988 int dumped = 0, err;
989
990 if (cb->strict_check) {
991 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
992 if (err < 0)
993 return err;
994 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
995 struct rtmsg *rtm = nlmsg_data(nlh);
996
997 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
998 }
999
1000 /* ipv4 does not use prefix flag */
1001 if (filter.flags & RTM_F_PREFIX)
1002 return skb->len;
1003
1004 if (filter.table_id) {
1005 tb = fib_get_table(net, filter.table_id);
1006 if (!tb) {
1007 if (rtnl_msg_family(cb->nlh) != PF_INET)
1008 return skb->len;
1009
1010 NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1011 return -ENOENT;
1012 }
1013
1014 rcu_read_lock();
1015 err = fib_table_dump(tb, skb, cb, &filter);
1016 rcu_read_unlock();
1017 return skb->len ? : err;
1018 }
1019
1020 s_h = cb->args[0];
1021 s_e = cb->args[1];
1022
1023 rcu_read_lock();
1024
1025 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1026 e = 0;
1027 head = &net->ipv4.fib_table_hash[h];
1028 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1029 if (e < s_e)
1030 goto next;
1031 if (dumped)
1032 memset(&cb->args[2], 0, sizeof(cb->args) -
1033 2 * sizeof(cb->args[0]));
1034 err = fib_table_dump(tb, skb, cb, &filter);
1035 if (err < 0) {
1036 if (likely(skb->len))
1037 goto out;
1038
1039 goto out_err;
1040 }
1041 dumped = 1;
1042 next:
1043 e++;
1044 }
1045 }
1046 out:
1047 err = skb->len;
1048 out_err:
1049 rcu_read_unlock();
1050
1051 cb->args[1] = e;
1052 cb->args[0] = h;
1053
1054 return err;
1055 }
1056
1057 /* Prepare and feed intra-kernel routing request.
1058 * Really, it should be netlink message, but :-( netlink
1059 * can be not configured, so that we feed it directly
1060 * to fib engine. It is legal, because all events occur
1061 * only when netlink is already locked.
1062 */
fib_magic(int cmd,int type,__be32 dst,int dst_len,struct in_ifaddr * ifa,u32 rt_priority)1063 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1064 struct in_ifaddr *ifa, u32 rt_priority)
1065 {
1066 struct net *net = dev_net(ifa->ifa_dev->dev);
1067 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1068 struct fib_table *tb;
1069 struct fib_config cfg = {
1070 .fc_protocol = RTPROT_KERNEL,
1071 .fc_type = type,
1072 .fc_dst = dst,
1073 .fc_dst_len = dst_len,
1074 .fc_priority = rt_priority,
1075 .fc_prefsrc = ifa->ifa_local,
1076 .fc_oif = ifa->ifa_dev->dev->ifindex,
1077 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1078 .fc_nlinfo = {
1079 .nl_net = net,
1080 },
1081 };
1082
1083 if (!tb_id)
1084 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1085
1086 tb = fib_new_table(net, tb_id);
1087 if (!tb)
1088 return;
1089
1090 cfg.fc_table = tb->tb_id;
1091
1092 if (type != RTN_LOCAL)
1093 cfg.fc_scope = RT_SCOPE_LINK;
1094 else
1095 cfg.fc_scope = RT_SCOPE_HOST;
1096
1097 if (cmd == RTM_NEWROUTE)
1098 fib_table_insert(net, tb, &cfg, NULL);
1099 else
1100 fib_table_delete(net, tb, &cfg, NULL);
1101 }
1102
fib_add_ifaddr(struct in_ifaddr * ifa)1103 void fib_add_ifaddr(struct in_ifaddr *ifa)
1104 {
1105 struct in_device *in_dev = ifa->ifa_dev;
1106 struct net_device *dev = in_dev->dev;
1107 struct in_ifaddr *prim = ifa;
1108 __be32 mask = ifa->ifa_mask;
1109 __be32 addr = ifa->ifa_local;
1110 __be32 prefix = ifa->ifa_address & mask;
1111
1112 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1113 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1114 if (!prim) {
1115 pr_warn("%s: bug: prim == NULL\n", __func__);
1116 return;
1117 }
1118 }
1119
1120 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1121
1122 if (!(dev->flags & IFF_UP))
1123 return;
1124
1125 /* Add broadcast address, if it is explicitly assigned. */
1126 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) {
1127 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1128 prim, 0);
1129 arp_invalidate(dev, ifa->ifa_broadcast, false);
1130 }
1131
1132 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1133 (prefix != addr || ifa->ifa_prefixlen < 32)) {
1134 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1135 fib_magic(RTM_NEWROUTE,
1136 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1137 prefix, ifa->ifa_prefixlen, prim,
1138 ifa->ifa_rt_priority);
1139
1140 /* Add the network broadcast address, when it makes sense */
1141 if (ifa->ifa_prefixlen < 31) {
1142 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1143 32, prim, 0);
1144 arp_invalidate(dev, prefix | ~mask, false);
1145 }
1146 }
1147 }
1148
fib_modify_prefix_metric(struct in_ifaddr * ifa,u32 new_metric)1149 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1150 {
1151 __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1152 struct in_device *in_dev = ifa->ifa_dev;
1153 struct net_device *dev = in_dev->dev;
1154
1155 if (!(dev->flags & IFF_UP) ||
1156 ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1157 ipv4_is_zeronet(prefix) ||
1158 (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1159 return;
1160
1161 /* add the new */
1162 fib_magic(RTM_NEWROUTE,
1163 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1164 prefix, ifa->ifa_prefixlen, ifa, new_metric);
1165
1166 /* delete the old */
1167 fib_magic(RTM_DELROUTE,
1168 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1169 prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1170 }
1171
1172 /* Delete primary or secondary address.
1173 * Optionally, on secondary address promotion consider the addresses
1174 * from subnet iprim as deleted, even if they are in device list.
1175 * In this case the secondary ifa can be in device list.
1176 */
fib_del_ifaddr(struct in_ifaddr * ifa,struct in_ifaddr * iprim)1177 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1178 {
1179 struct in_device *in_dev = ifa->ifa_dev;
1180 struct net_device *dev = in_dev->dev;
1181 struct in_ifaddr *ifa1;
1182 struct in_ifaddr *prim = ifa, *prim1 = NULL;
1183 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1184 __be32 any = ifa->ifa_address & ifa->ifa_mask;
1185 #define LOCAL_OK 1
1186 #define BRD_OK 2
1187 #define BRD0_OK 4
1188 #define BRD1_OK 8
1189 unsigned int ok = 0;
1190 int subnet = 0; /* Primary network */
1191 int gone = 1; /* Address is missing */
1192 int same_prefsrc = 0; /* Another primary with same IP */
1193
1194 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1195 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1196 if (!prim) {
1197 /* if the device has been deleted, we don't perform
1198 * address promotion
1199 */
1200 if (!in_dev->dead)
1201 pr_warn("%s: bug: prim == NULL\n", __func__);
1202 return;
1203 }
1204 if (iprim && iprim != prim) {
1205 pr_warn("%s: bug: iprim != prim\n", __func__);
1206 return;
1207 }
1208 } else if (!ipv4_is_zeronet(any) &&
1209 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1210 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1211 fib_magic(RTM_DELROUTE,
1212 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1213 any, ifa->ifa_prefixlen, prim, 0);
1214 subnet = 1;
1215 }
1216
1217 if (in_dev->dead)
1218 goto no_promotions;
1219
1220 /* Deletion is more complicated than add.
1221 * We should take care of not to delete too much :-)
1222 *
1223 * Scan address list to be sure that addresses are really gone.
1224 */
1225 rcu_read_lock();
1226 in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1227 if (ifa1 == ifa) {
1228 /* promotion, keep the IP */
1229 gone = 0;
1230 continue;
1231 }
1232 /* Ignore IFAs from our subnet */
1233 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1234 inet_ifa_match(ifa1->ifa_address, iprim))
1235 continue;
1236
1237 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1238 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1239 /* Another address from our subnet? */
1240 if (ifa1->ifa_mask == prim->ifa_mask &&
1241 inet_ifa_match(ifa1->ifa_address, prim))
1242 prim1 = prim;
1243 else {
1244 /* We reached the secondaries, so
1245 * same_prefsrc should be determined.
1246 */
1247 if (!same_prefsrc)
1248 continue;
1249 /* Search new prim1 if ifa1 is not
1250 * using the current prim1
1251 */
1252 if (!prim1 ||
1253 ifa1->ifa_mask != prim1->ifa_mask ||
1254 !inet_ifa_match(ifa1->ifa_address, prim1))
1255 prim1 = inet_ifa_byprefix(in_dev,
1256 ifa1->ifa_address,
1257 ifa1->ifa_mask);
1258 if (!prim1)
1259 continue;
1260 if (prim1->ifa_local != prim->ifa_local)
1261 continue;
1262 }
1263 } else {
1264 if (prim->ifa_local != ifa1->ifa_local)
1265 continue;
1266 prim1 = ifa1;
1267 if (prim != prim1)
1268 same_prefsrc = 1;
1269 }
1270 if (ifa->ifa_local == ifa1->ifa_local)
1271 ok |= LOCAL_OK;
1272 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1273 ok |= BRD_OK;
1274 if (brd == ifa1->ifa_broadcast)
1275 ok |= BRD1_OK;
1276 if (any == ifa1->ifa_broadcast)
1277 ok |= BRD0_OK;
1278 /* primary has network specific broadcasts */
1279 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1280 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1281 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1282
1283 if (!ipv4_is_zeronet(any1)) {
1284 if (ifa->ifa_broadcast == brd1 ||
1285 ifa->ifa_broadcast == any1)
1286 ok |= BRD_OK;
1287 if (brd == brd1 || brd == any1)
1288 ok |= BRD1_OK;
1289 if (any == brd1 || any == any1)
1290 ok |= BRD0_OK;
1291 }
1292 }
1293 }
1294 rcu_read_unlock();
1295
1296 no_promotions:
1297 if (!(ok & BRD_OK))
1298 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1299 prim, 0);
1300 if (subnet && ifa->ifa_prefixlen < 31) {
1301 if (!(ok & BRD1_OK))
1302 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1303 prim, 0);
1304 if (!(ok & BRD0_OK))
1305 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1306 prim, 0);
1307 }
1308 if (!(ok & LOCAL_OK)) {
1309 unsigned int addr_type;
1310
1311 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1312
1313 /* Check, that this local address finally disappeared. */
1314 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1315 ifa->ifa_local);
1316 if (gone && addr_type != RTN_LOCAL) {
1317 /* And the last, but not the least thing.
1318 * We must flush stray FIB entries.
1319 *
1320 * First of all, we scan fib_info list searching
1321 * for stray nexthop entries, then ignite fib_flush.
1322 */
1323 if (fib_sync_down_addr(dev, ifa->ifa_local))
1324 fib_flush(dev_net(dev));
1325 }
1326 }
1327 #undef LOCAL_OK
1328 #undef BRD_OK
1329 #undef BRD0_OK
1330 #undef BRD1_OK
1331 }
1332
nl_fib_lookup(struct net * net,struct fib_result_nl * frn)1333 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1334 {
1335
1336 struct fib_result res;
1337 struct flowi4 fl4 = {
1338 .flowi4_mark = frn->fl_mark,
1339 .daddr = frn->fl_addr,
1340 .flowi4_tos = frn->fl_tos,
1341 .flowi4_scope = frn->fl_scope,
1342 };
1343 struct fib_table *tb;
1344
1345 rcu_read_lock();
1346
1347 tb = fib_get_table(net, frn->tb_id_in);
1348
1349 frn->err = -ENOENT;
1350 if (tb) {
1351 local_bh_disable();
1352
1353 frn->tb_id = tb->tb_id;
1354 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1355
1356 if (!frn->err) {
1357 frn->prefixlen = res.prefixlen;
1358 frn->nh_sel = res.nh_sel;
1359 frn->type = res.type;
1360 frn->scope = res.scope;
1361 }
1362 local_bh_enable();
1363 }
1364
1365 rcu_read_unlock();
1366 }
1367
nl_fib_input(struct sk_buff * skb)1368 static void nl_fib_input(struct sk_buff *skb)
1369 {
1370 struct net *net;
1371 struct fib_result_nl *frn;
1372 struct nlmsghdr *nlh;
1373 u32 portid;
1374
1375 net = sock_net(skb->sk);
1376 nlh = nlmsg_hdr(skb);
1377 if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1378 skb->len < nlh->nlmsg_len ||
1379 nlmsg_len(nlh) < sizeof(*frn))
1380 return;
1381
1382 skb = netlink_skb_clone(skb, GFP_KERNEL);
1383 if (!skb)
1384 return;
1385 nlh = nlmsg_hdr(skb);
1386
1387 frn = nlmsg_data(nlh);
1388 nl_fib_lookup(net, frn);
1389
1390 portid = NETLINK_CB(skb).portid; /* netlink portid */
1391 NETLINK_CB(skb).portid = 0; /* from kernel */
1392 NETLINK_CB(skb).dst_group = 0; /* unicast */
1393 nlmsg_unicast(net->ipv4.fibnl, skb, portid);
1394 }
1395
nl_fib_lookup_init(struct net * net)1396 static int __net_init nl_fib_lookup_init(struct net *net)
1397 {
1398 struct sock *sk;
1399 struct netlink_kernel_cfg cfg = {
1400 .input = nl_fib_input,
1401 };
1402
1403 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1404 if (!sk)
1405 return -EAFNOSUPPORT;
1406 net->ipv4.fibnl = sk;
1407 return 0;
1408 }
1409
nl_fib_lookup_exit(struct net * net)1410 static void nl_fib_lookup_exit(struct net *net)
1411 {
1412 netlink_kernel_release(net->ipv4.fibnl);
1413 net->ipv4.fibnl = NULL;
1414 }
1415
fib_disable_ip(struct net_device * dev,unsigned long event,bool force)1416 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1417 bool force)
1418 {
1419 if (fib_sync_down_dev(dev, event, force))
1420 fib_flush(dev_net(dev));
1421 else
1422 rt_cache_flush(dev_net(dev));
1423 arp_ifdown(dev);
1424 }
1425
fib_inetaddr_event(struct notifier_block * this,unsigned long event,void * ptr)1426 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1427 {
1428 struct in_ifaddr *ifa = ptr;
1429 struct net_device *dev = ifa->ifa_dev->dev;
1430 struct net *net = dev_net(dev);
1431
1432 switch (event) {
1433 case NETDEV_UP:
1434 fib_add_ifaddr(ifa);
1435 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1436 fib_sync_up(dev, RTNH_F_DEAD);
1437 #endif
1438 atomic_inc(&net->ipv4.dev_addr_genid);
1439 rt_cache_flush(dev_net(dev));
1440 break;
1441 case NETDEV_DOWN:
1442 fib_del_ifaddr(ifa, NULL);
1443 atomic_inc(&net->ipv4.dev_addr_genid);
1444 if (!ifa->ifa_dev->ifa_list) {
1445 /* Last address was deleted from this interface.
1446 * Disable IP.
1447 */
1448 fib_disable_ip(dev, event, true);
1449 } else {
1450 rt_cache_flush(dev_net(dev));
1451 }
1452 break;
1453 }
1454 return NOTIFY_DONE;
1455 }
1456
fib_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1457 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1458 {
1459 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1460 struct netdev_notifier_changeupper_info *upper_info = ptr;
1461 struct netdev_notifier_info_ext *info_ext = ptr;
1462 struct in_device *in_dev;
1463 struct net *net = dev_net(dev);
1464 struct in_ifaddr *ifa;
1465 unsigned int flags;
1466
1467 if (event == NETDEV_UNREGISTER) {
1468 fib_disable_ip(dev, event, true);
1469 rt_flush_dev(dev);
1470 return NOTIFY_DONE;
1471 }
1472
1473 in_dev = __in_dev_get_rtnl(dev);
1474 if (!in_dev)
1475 return NOTIFY_DONE;
1476
1477 switch (event) {
1478 case NETDEV_UP:
1479 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1480 fib_add_ifaddr(ifa);
1481 }
1482 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1483 fib_sync_up(dev, RTNH_F_DEAD);
1484 #endif
1485 atomic_inc(&net->ipv4.dev_addr_genid);
1486 rt_cache_flush(net);
1487 break;
1488 case NETDEV_DOWN:
1489 fib_disable_ip(dev, event, false);
1490 break;
1491 case NETDEV_CHANGE:
1492 flags = dev_get_flags(dev);
1493 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1494 fib_sync_up(dev, RTNH_F_LINKDOWN);
1495 else
1496 fib_sync_down_dev(dev, event, false);
1497 rt_cache_flush(net);
1498 break;
1499 case NETDEV_CHANGEMTU:
1500 fib_sync_mtu(dev, info_ext->ext.mtu);
1501 rt_cache_flush(net);
1502 break;
1503 case NETDEV_CHANGEUPPER:
1504 upper_info = ptr;
1505 /* flush all routes if dev is linked to or unlinked from
1506 * an L3 master device (e.g., VRF)
1507 */
1508 if (upper_info->upper_dev &&
1509 netif_is_l3_master(upper_info->upper_dev))
1510 fib_disable_ip(dev, NETDEV_DOWN, true);
1511 break;
1512 }
1513 return NOTIFY_DONE;
1514 }
1515
1516 static struct notifier_block fib_inetaddr_notifier = {
1517 .notifier_call = fib_inetaddr_event,
1518 };
1519
1520 static struct notifier_block fib_netdev_notifier = {
1521 .notifier_call = fib_netdev_event,
1522 };
1523
ip_fib_net_init(struct net * net)1524 static int __net_init ip_fib_net_init(struct net *net)
1525 {
1526 int err;
1527 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1528
1529 err = fib4_notifier_init(net);
1530 if (err)
1531 return err;
1532
1533 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1534 /* Default to 3-tuple */
1535 net->ipv4.sysctl_fib_multipath_hash_fields =
1536 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
1537 #endif
1538
1539 /* Avoid false sharing : Use at least a full cache line */
1540 size = max_t(size_t, size, L1_CACHE_BYTES);
1541
1542 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1543 if (!net->ipv4.fib_table_hash) {
1544 err = -ENOMEM;
1545 goto err_table_hash_alloc;
1546 }
1547
1548 err = fib4_rules_init(net);
1549 if (err < 0)
1550 goto err_rules_init;
1551 return 0;
1552
1553 err_rules_init:
1554 kfree(net->ipv4.fib_table_hash);
1555 err_table_hash_alloc:
1556 fib4_notifier_exit(net);
1557 return err;
1558 }
1559
ip_fib_net_exit(struct net * net)1560 static void ip_fib_net_exit(struct net *net)
1561 {
1562 int i;
1563
1564 ASSERT_RTNL();
1565 #ifdef CONFIG_IP_MULTIPLE_TABLES
1566 RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1567 RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1568 #endif
1569 /* Destroy the tables in reverse order to guarantee that the
1570 * local table, ID 255, is destroyed before the main table, ID
1571 * 254. This is necessary as the local table may contain
1572 * references to data contained in the main table.
1573 */
1574 for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1575 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1576 struct hlist_node *tmp;
1577 struct fib_table *tb;
1578
1579 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1580 hlist_del(&tb->tb_hlist);
1581 fib_table_flush(net, tb, true);
1582 fib_free_table(tb);
1583 }
1584 }
1585
1586 #ifdef CONFIG_IP_MULTIPLE_TABLES
1587 fib4_rules_exit(net);
1588 #endif
1589
1590 kfree(net->ipv4.fib_table_hash);
1591 fib4_notifier_exit(net);
1592 }
1593
fib_net_init(struct net * net)1594 static int __net_init fib_net_init(struct net *net)
1595 {
1596 int error;
1597
1598 #ifdef CONFIG_IP_ROUTE_CLASSID
1599 atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
1600 #endif
1601 error = ip_fib_net_init(net);
1602 if (error < 0)
1603 goto out;
1604 error = nl_fib_lookup_init(net);
1605 if (error < 0)
1606 goto out_nlfl;
1607 error = fib_proc_init(net);
1608 if (error < 0)
1609 goto out_proc;
1610 out:
1611 return error;
1612
1613 out_proc:
1614 nl_fib_lookup_exit(net);
1615 out_nlfl:
1616 rtnl_lock();
1617 ip_fib_net_exit(net);
1618 rtnl_unlock();
1619 goto out;
1620 }
1621
fib_net_exit(struct net * net)1622 static void __net_exit fib_net_exit(struct net *net)
1623 {
1624 fib_proc_exit(net);
1625 nl_fib_lookup_exit(net);
1626 }
1627
fib_net_exit_batch(struct list_head * net_list)1628 static void __net_exit fib_net_exit_batch(struct list_head *net_list)
1629 {
1630 struct net *net;
1631
1632 rtnl_lock();
1633 list_for_each_entry(net, net_list, exit_list)
1634 ip_fib_net_exit(net);
1635
1636 rtnl_unlock();
1637 }
1638
1639 static struct pernet_operations fib_net_ops = {
1640 .init = fib_net_init,
1641 .exit = fib_net_exit,
1642 .exit_batch = fib_net_exit_batch,
1643 };
1644
ip_fib_init(void)1645 void __init ip_fib_init(void)
1646 {
1647 fib_trie_init();
1648
1649 register_pernet_subsys(&fib_net_ops);
1650
1651 register_netdevice_notifier(&fib_netdev_notifier);
1652 register_inetaddr_notifier(&fib_inetaddr_notifier);
1653
1654 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1655 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1656 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1657 }
1658