1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: FIB frontend.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/module.h>
13 #include <linux/uaccess.h>
14 #include <linux/bitops.h>
15 #include <linux/capability.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/string.h>
20 #include <linux/socket.h>
21 #include <linux/sockios.h>
22 #include <linux/errno.h>
23 #include <linux/in.h>
24 #include <linux/inet.h>
25 #include <linux/inetdevice.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_addr.h>
28 #include <linux/if_arp.h>
29 #include <linux/skbuff.h>
30 #include <linux/cache.h>
31 #include <linux/init.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34
35 #include <net/ip.h>
36 #include <net/protocol.h>
37 #include <net/route.h>
38 #include <net/tcp.h>
39 #include <net/sock.h>
40 #include <net/arp.h>
41 #include <net/ip_fib.h>
42 #include <net/nexthop.h>
43 #include <net/rtnetlink.h>
44 #include <net/xfrm.h>
45 #include <net/l3mdev.h>
46 #include <net/lwtunnel.h>
47 #include <trace/events/fib.h>
48
49 #ifndef CONFIG_IP_MULTIPLE_TABLES
50
fib4_rules_init(struct net * net)51 static int __net_init fib4_rules_init(struct net *net)
52 {
53 struct fib_table *local_table, *main_table;
54
55 main_table = fib_trie_table(RT_TABLE_MAIN, NULL);
56 if (!main_table)
57 return -ENOMEM;
58
59 local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
60 if (!local_table)
61 goto fail;
62
63 hlist_add_head_rcu(&local_table->tb_hlist,
64 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
65 hlist_add_head_rcu(&main_table->tb_hlist,
66 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
67 return 0;
68
69 fail:
70 fib_free_table(main_table);
71 return -ENOMEM;
72 }
73
fib4_has_custom_rules(struct net * net)74 static bool fib4_has_custom_rules(struct net *net)
75 {
76 return false;
77 }
78 #else
79
fib_new_table(struct net * net,u32 id)80 struct fib_table *fib_new_table(struct net *net, u32 id)
81 {
82 struct fib_table *tb, *alias = NULL;
83 unsigned int h;
84
85 if (id == 0)
86 id = RT_TABLE_MAIN;
87 tb = fib_get_table(net, id);
88 if (tb)
89 return tb;
90
91 if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
92 alias = fib_new_table(net, RT_TABLE_MAIN);
93
94 tb = fib_trie_table(id, alias);
95 if (!tb)
96 return NULL;
97
98 switch (id) {
99 case RT_TABLE_MAIN:
100 rcu_assign_pointer(net->ipv4.fib_main, tb);
101 break;
102 case RT_TABLE_DEFAULT:
103 rcu_assign_pointer(net->ipv4.fib_default, tb);
104 break;
105 default:
106 break;
107 }
108
109 h = id & (FIB_TABLE_HASHSZ - 1);
110 hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
111 return tb;
112 }
113 EXPORT_SYMBOL_GPL(fib_new_table);
114
115 /* caller must hold either rtnl or rcu read lock */
fib_get_table(struct net * net,u32 id)116 struct fib_table *fib_get_table(struct net *net, u32 id)
117 {
118 struct fib_table *tb;
119 struct hlist_head *head;
120 unsigned int h;
121
122 if (id == 0)
123 id = RT_TABLE_MAIN;
124 h = id & (FIB_TABLE_HASHSZ - 1);
125
126 head = &net->ipv4.fib_table_hash[h];
127 hlist_for_each_entry_rcu(tb, head, tb_hlist,
128 lockdep_rtnl_is_held()) {
129 if (tb->tb_id == id)
130 return tb;
131 }
132 return NULL;
133 }
134
fib4_has_custom_rules(struct net * net)135 static bool fib4_has_custom_rules(struct net *net)
136 {
137 return net->ipv4.fib_has_custom_rules;
138 }
139 #endif /* CONFIG_IP_MULTIPLE_TABLES */
140
fib_replace_table(struct net * net,struct fib_table * old,struct fib_table * new)141 static void fib_replace_table(struct net *net, struct fib_table *old,
142 struct fib_table *new)
143 {
144 #ifdef CONFIG_IP_MULTIPLE_TABLES
145 switch (new->tb_id) {
146 case RT_TABLE_MAIN:
147 rcu_assign_pointer(net->ipv4.fib_main, new);
148 break;
149 case RT_TABLE_DEFAULT:
150 rcu_assign_pointer(net->ipv4.fib_default, new);
151 break;
152 default:
153 break;
154 }
155
156 #endif
157 /* replace the old table in the hlist */
158 hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
159 }
160
fib_unmerge(struct net * net)161 int fib_unmerge(struct net *net)
162 {
163 struct fib_table *old, *new, *main_table;
164
165 /* attempt to fetch local table if it has been allocated */
166 old = fib_get_table(net, RT_TABLE_LOCAL);
167 if (!old)
168 return 0;
169
170 new = fib_trie_unmerge(old);
171 if (!new)
172 return -ENOMEM;
173
174 /* table is already unmerged */
175 if (new == old)
176 return 0;
177
178 /* replace merged table with clean table */
179 fib_replace_table(net, old, new);
180 fib_free_table(old);
181
182 /* attempt to fetch main table if it has been allocated */
183 main_table = fib_get_table(net, RT_TABLE_MAIN);
184 if (!main_table)
185 return 0;
186
187 /* flush local entries from main table */
188 fib_table_flush_external(main_table);
189
190 return 0;
191 }
192
fib_flush(struct net * net)193 void fib_flush(struct net *net)
194 {
195 int flushed = 0;
196 unsigned int h;
197
198 for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
199 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
200 struct hlist_node *tmp;
201 struct fib_table *tb;
202
203 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
204 flushed += fib_table_flush(net, tb, false);
205 }
206
207 if (flushed)
208 rt_cache_flush(net);
209 }
210
211 /*
212 * Find address type as if only "dev" was present in the system. If
213 * on_dev is NULL then all interfaces are taken into consideration.
214 */
__inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr,u32 tb_id)215 static inline unsigned int __inet_dev_addr_type(struct net *net,
216 const struct net_device *dev,
217 __be32 addr, u32 tb_id)
218 {
219 struct flowi4 fl4 = { .daddr = addr };
220 struct fib_result res;
221 unsigned int ret = RTN_BROADCAST;
222 struct fib_table *table;
223
224 if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
225 return RTN_BROADCAST;
226 if (ipv4_is_multicast(addr))
227 return RTN_MULTICAST;
228
229 rcu_read_lock();
230
231 table = fib_get_table(net, tb_id);
232 if (table) {
233 ret = RTN_UNICAST;
234 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
235 struct fib_nh_common *nhc = fib_info_nhc(res.fi, 0);
236
237 if (!dev || dev == nhc->nhc_dev)
238 ret = res.type;
239 }
240 }
241
242 rcu_read_unlock();
243 return ret;
244 }
245
inet_addr_type_table(struct net * net,__be32 addr,u32 tb_id)246 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
247 {
248 return __inet_dev_addr_type(net, NULL, addr, tb_id);
249 }
250 EXPORT_SYMBOL(inet_addr_type_table);
251
inet_addr_type(struct net * net,__be32 addr)252 unsigned int inet_addr_type(struct net *net, __be32 addr)
253 {
254 return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
255 }
256 EXPORT_SYMBOL(inet_addr_type);
257
inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr)258 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
259 __be32 addr)
260 {
261 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
262
263 return __inet_dev_addr_type(net, dev, addr, rt_table);
264 }
265 EXPORT_SYMBOL(inet_dev_addr_type);
266
267 /* inet_addr_type with dev == NULL but using the table from a dev
268 * if one is associated
269 */
inet_addr_type_dev_table(struct net * net,const struct net_device * dev,__be32 addr)270 unsigned int inet_addr_type_dev_table(struct net *net,
271 const struct net_device *dev,
272 __be32 addr)
273 {
274 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
275
276 return __inet_dev_addr_type(net, NULL, addr, rt_table);
277 }
278 EXPORT_SYMBOL(inet_addr_type_dev_table);
279
fib_compute_spec_dst(struct sk_buff * skb)280 __be32 fib_compute_spec_dst(struct sk_buff *skb)
281 {
282 struct net_device *dev = skb->dev;
283 struct in_device *in_dev;
284 struct fib_result res;
285 struct rtable *rt;
286 struct net *net;
287 int scope;
288
289 rt = skb_rtable(skb);
290 if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
291 RTCF_LOCAL)
292 return ip_hdr(skb)->daddr;
293
294 in_dev = __in_dev_get_rcu(dev);
295
296 net = dev_net(dev);
297
298 scope = RT_SCOPE_UNIVERSE;
299 if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
300 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
301 struct flowi4 fl4 = {
302 .flowi4_iif = LOOPBACK_IFINDEX,
303 .flowi4_oif = l3mdev_master_ifindex_rcu(dev),
304 .daddr = ip_hdr(skb)->saddr,
305 .flowi4_tos = ip_hdr(skb)->tos & IPTOS_RT_MASK,
306 .flowi4_scope = scope,
307 .flowi4_mark = vmark ? skb->mark : 0,
308 };
309 if (!fib_lookup(net, &fl4, &res, 0))
310 return fib_result_prefsrc(net, &res);
311 } else {
312 scope = RT_SCOPE_LINK;
313 }
314
315 return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
316 }
317
fib_info_nh_uses_dev(struct fib_info * fi,const struct net_device * dev)318 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
319 {
320 bool dev_match = false;
321 #ifdef CONFIG_IP_ROUTE_MULTIPATH
322 if (unlikely(fi->nh)) {
323 dev_match = nexthop_uses_dev(fi->nh, dev);
324 } else {
325 int ret;
326
327 for (ret = 0; ret < fib_info_num_path(fi); ret++) {
328 const struct fib_nh_common *nhc = fib_info_nhc(fi, ret);
329
330 if (nhc_l3mdev_matches_dev(nhc, dev)) {
331 dev_match = true;
332 break;
333 }
334 }
335 }
336 #else
337 if (fib_info_nhc(fi, 0)->nhc_dev == dev)
338 dev_match = true;
339 #endif
340
341 return dev_match;
342 }
343 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
344
345 /* Given (packet source, input interface) and optional (dst, oif, tos):
346 * - (main) check, that source is valid i.e. not broadcast or our local
347 * address.
348 * - figure out what "logical" interface this packet arrived
349 * and calculate "specific destination" address.
350 * - check, that packet arrived from expected physical interface.
351 * called with rcu_read_lock()
352 */
__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)353 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
354 u8 tos, int oif, struct net_device *dev,
355 int rpf, struct in_device *idev, u32 *itag)
356 {
357 struct net *net = dev_net(dev);
358 struct flow_keys flkeys;
359 int ret, no_addr;
360 struct fib_result res;
361 struct flowi4 fl4;
362 bool dev_match;
363
364 fl4.flowi4_oif = 0;
365 fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev);
366 if (!fl4.flowi4_iif)
367 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
368 fl4.daddr = src;
369 fl4.saddr = dst;
370 fl4.flowi4_tos = tos;
371 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
372 fl4.flowi4_tun_key.tun_id = 0;
373 fl4.flowi4_flags = 0;
374 fl4.flowi4_uid = sock_net_uid(net, NULL);
375 fl4.flowi4_multipath_hash = 0;
376
377 no_addr = idev->ifa_list == NULL;
378
379 fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
380 if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
381 fl4.flowi4_proto = 0;
382 fl4.fl4_sport = 0;
383 fl4.fl4_dport = 0;
384 } else {
385 swap(fl4.fl4_sport, fl4.fl4_dport);
386 }
387
388 if (fib_lookup(net, &fl4, &res, 0))
389 goto last_resort;
390 if (res.type != RTN_UNICAST &&
391 (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
392 goto e_inval;
393 fib_combine_itag(itag, &res);
394
395 dev_match = fib_info_nh_uses_dev(res.fi, dev);
396 /* This is not common, loopback packets retain skb_dst so normally they
397 * would not even hit this slow path.
398 */
399 dev_match = dev_match || (res.type == RTN_LOCAL &&
400 dev == net->loopback_dev);
401 if (dev_match) {
402 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_LINK;
403 return ret;
404 }
405 if (no_addr)
406 goto last_resort;
407 if (rpf == 1)
408 goto e_rpf;
409 fl4.flowi4_oif = dev->ifindex;
410
411 ret = 0;
412 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
413 if (res.type == RTN_UNICAST)
414 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_LINK;
415 }
416 return ret;
417
418 last_resort:
419 if (rpf)
420 goto e_rpf;
421 *itag = 0;
422 return 0;
423
424 e_inval:
425 return -EINVAL;
426 e_rpf:
427 return -EXDEV;
428 }
429
430 /* 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)431 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
432 u8 tos, int oif, struct net_device *dev,
433 struct in_device *idev, u32 *itag)
434 {
435 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
436 struct net *net = dev_net(dev);
437
438 if (!r && !fib_num_tclassid_users(net) &&
439 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
440 if (IN_DEV_ACCEPT_LOCAL(idev))
441 goto ok;
442 /* with custom local routes in place, checking local addresses
443 * only will be too optimistic, with custom rules, checking
444 * local addresses only can be too strict, e.g. due to vrf
445 */
446 if (net->ipv4.fib_has_custom_local_routes ||
447 fib4_has_custom_rules(net))
448 goto full_check;
449 if (inet_lookup_ifaddr_rcu(net, src))
450 return -EINVAL;
451
452 ok:
453 *itag = 0;
454 return 0;
455 }
456
457 full_check:
458 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
459 }
460
sk_extract_addr(struct sockaddr * addr)461 static inline __be32 sk_extract_addr(struct sockaddr *addr)
462 {
463 return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
464 }
465
put_rtax(struct nlattr * mx,int len,int type,u32 value)466 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
467 {
468 struct nlattr *nla;
469
470 nla = (struct nlattr *) ((char *) mx + len);
471 nla->nla_type = type;
472 nla->nla_len = nla_attr_size(4);
473 *(u32 *) nla_data(nla) = value;
474
475 return len + nla_total_size(4);
476 }
477
rtentry_to_fib_config(struct net * net,int cmd,struct rtentry * rt,struct fib_config * cfg)478 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
479 struct fib_config *cfg)
480 {
481 __be32 addr;
482 int plen;
483
484 memset(cfg, 0, sizeof(*cfg));
485 cfg->fc_nlinfo.nl_net = net;
486
487 if (rt->rt_dst.sa_family != AF_INET)
488 return -EAFNOSUPPORT;
489
490 /*
491 * Check mask for validity:
492 * a) it must be contiguous.
493 * b) destination must have all host bits clear.
494 * c) if application forgot to set correct family (AF_INET),
495 * reject request unless it is absolutely clear i.e.
496 * both family and mask are zero.
497 */
498 plen = 32;
499 addr = sk_extract_addr(&rt->rt_dst);
500 if (!(rt->rt_flags & RTF_HOST)) {
501 __be32 mask = sk_extract_addr(&rt->rt_genmask);
502
503 if (rt->rt_genmask.sa_family != AF_INET) {
504 if (mask || rt->rt_genmask.sa_family)
505 return -EAFNOSUPPORT;
506 }
507
508 if (bad_mask(mask, addr))
509 return -EINVAL;
510
511 plen = inet_mask_len(mask);
512 }
513
514 cfg->fc_dst_len = plen;
515 cfg->fc_dst = addr;
516
517 if (cmd != SIOCDELRT) {
518 cfg->fc_nlflags = NLM_F_CREATE;
519 cfg->fc_protocol = RTPROT_BOOT;
520 }
521
522 if (rt->rt_metric)
523 cfg->fc_priority = rt->rt_metric - 1;
524
525 if (rt->rt_flags & RTF_REJECT) {
526 cfg->fc_scope = RT_SCOPE_HOST;
527 cfg->fc_type = RTN_UNREACHABLE;
528 return 0;
529 }
530
531 cfg->fc_scope = RT_SCOPE_NOWHERE;
532 cfg->fc_type = RTN_UNICAST;
533
534 if (rt->rt_dev) {
535 char *colon;
536 struct net_device *dev;
537 char devname[IFNAMSIZ];
538
539 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
540 return -EFAULT;
541
542 devname[IFNAMSIZ-1] = 0;
543 colon = strchr(devname, ':');
544 if (colon)
545 *colon = 0;
546 dev = __dev_get_by_name(net, devname);
547 if (!dev)
548 return -ENODEV;
549 cfg->fc_oif = dev->ifindex;
550 cfg->fc_table = l3mdev_fib_table(dev);
551 if (colon) {
552 const struct in_ifaddr *ifa;
553 struct in_device *in_dev;
554
555 in_dev = __in_dev_get_rtnl(dev);
556 if (!in_dev)
557 return -ENODEV;
558
559 *colon = ':';
560
561 rcu_read_lock();
562 in_dev_for_each_ifa_rcu(ifa, in_dev) {
563 if (strcmp(ifa->ifa_label, devname) == 0)
564 break;
565 }
566 rcu_read_unlock();
567
568 if (!ifa)
569 return -ENODEV;
570 cfg->fc_prefsrc = ifa->ifa_local;
571 }
572 }
573
574 addr = sk_extract_addr(&rt->rt_gateway);
575 if (rt->rt_gateway.sa_family == AF_INET && addr) {
576 unsigned int addr_type;
577
578 cfg->fc_gw4 = addr;
579 cfg->fc_gw_family = AF_INET;
580 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
581 if (rt->rt_flags & RTF_GATEWAY &&
582 addr_type == RTN_UNICAST)
583 cfg->fc_scope = RT_SCOPE_UNIVERSE;
584 }
585
586 if (!cfg->fc_table)
587 cfg->fc_table = RT_TABLE_MAIN;
588
589 if (cmd == SIOCDELRT)
590 return 0;
591
592 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
593 return -EINVAL;
594
595 if (cfg->fc_scope == RT_SCOPE_NOWHERE)
596 cfg->fc_scope = RT_SCOPE_LINK;
597
598 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
599 struct nlattr *mx;
600 int len = 0;
601
602 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
603 if (!mx)
604 return -ENOMEM;
605
606 if (rt->rt_flags & RTF_MTU)
607 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
608
609 if (rt->rt_flags & RTF_WINDOW)
610 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
611
612 if (rt->rt_flags & RTF_IRTT)
613 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
614
615 cfg->fc_mx = mx;
616 cfg->fc_mx_len = len;
617 }
618
619 return 0;
620 }
621
622 /*
623 * Handle IP routing ioctl calls.
624 * These are used to manipulate the routing tables
625 */
ip_rt_ioctl(struct net * net,unsigned int cmd,struct rtentry * rt)626 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
627 {
628 struct fib_config cfg;
629 int err;
630
631 switch (cmd) {
632 case SIOCADDRT: /* Add a route */
633 case SIOCDELRT: /* Delete a route */
634 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
635 return -EPERM;
636
637 rtnl_lock();
638 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
639 if (err == 0) {
640 struct fib_table *tb;
641
642 if (cmd == SIOCDELRT) {
643 tb = fib_get_table(net, cfg.fc_table);
644 if (tb)
645 err = fib_table_delete(net, tb, &cfg,
646 NULL);
647 else
648 err = -ESRCH;
649 } else {
650 tb = fib_new_table(net, cfg.fc_table);
651 if (tb)
652 err = fib_table_insert(net, tb,
653 &cfg, NULL);
654 else
655 err = -ENOBUFS;
656 }
657
658 /* allocated by rtentry_to_fib_config() */
659 kfree(cfg.fc_mx);
660 }
661 rtnl_unlock();
662 return err;
663 }
664 return -EINVAL;
665 }
666
667 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
668 [RTA_UNSPEC] = { .strict_start_type = RTA_DPORT + 1 },
669 [RTA_DST] = { .type = NLA_U32 },
670 [RTA_SRC] = { .type = NLA_U32 },
671 [RTA_IIF] = { .type = NLA_U32 },
672 [RTA_OIF] = { .type = NLA_U32 },
673 [RTA_GATEWAY] = { .type = NLA_U32 },
674 [RTA_PRIORITY] = { .type = NLA_U32 },
675 [RTA_PREFSRC] = { .type = NLA_U32 },
676 [RTA_METRICS] = { .type = NLA_NESTED },
677 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
678 [RTA_FLOW] = { .type = NLA_U32 },
679 [RTA_ENCAP_TYPE] = { .type = NLA_U16 },
680 [RTA_ENCAP] = { .type = NLA_NESTED },
681 [RTA_UID] = { .type = NLA_U32 },
682 [RTA_MARK] = { .type = NLA_U32 },
683 [RTA_TABLE] = { .type = NLA_U32 },
684 [RTA_IP_PROTO] = { .type = NLA_U8 },
685 [RTA_SPORT] = { .type = NLA_U16 },
686 [RTA_DPORT] = { .type = NLA_U16 },
687 [RTA_NH_ID] = { .type = NLA_U32 },
688 };
689
fib_gw_from_via(struct fib_config * cfg,struct nlattr * nla,struct netlink_ext_ack * extack)690 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
691 struct netlink_ext_ack *extack)
692 {
693 struct rtvia *via;
694 int alen;
695
696 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
697 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
698 return -EINVAL;
699 }
700
701 via = nla_data(nla);
702 alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
703
704 switch (via->rtvia_family) {
705 case AF_INET:
706 if (alen != sizeof(__be32)) {
707 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
708 return -EINVAL;
709 }
710 cfg->fc_gw_family = AF_INET;
711 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
712 break;
713 case AF_INET6:
714 #if IS_ENABLED(CONFIG_IPV6)
715 if (alen != sizeof(struct in6_addr)) {
716 NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
717 return -EINVAL;
718 }
719 cfg->fc_gw_family = AF_INET6;
720 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
721 #else
722 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
723 return -EINVAL;
724 #endif
725 break;
726 default:
727 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
728 return -EINVAL;
729 }
730
731 return 0;
732 }
733
rtm_to_fib_config(struct net * net,struct sk_buff * skb,struct nlmsghdr * nlh,struct fib_config * cfg,struct netlink_ext_ack * extack)734 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
735 struct nlmsghdr *nlh, struct fib_config *cfg,
736 struct netlink_ext_ack *extack)
737 {
738 bool has_gw = false, has_via = false;
739 struct nlattr *attr;
740 int err, remaining;
741 struct rtmsg *rtm;
742
743 err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
744 rtm_ipv4_policy, extack);
745 if (err < 0)
746 goto errout;
747
748 memset(cfg, 0, sizeof(*cfg));
749
750 rtm = nlmsg_data(nlh);
751 cfg->fc_dst_len = rtm->rtm_dst_len;
752 cfg->fc_tos = rtm->rtm_tos;
753 cfg->fc_table = rtm->rtm_table;
754 cfg->fc_protocol = rtm->rtm_protocol;
755 cfg->fc_scope = rtm->rtm_scope;
756 cfg->fc_type = rtm->rtm_type;
757 cfg->fc_flags = rtm->rtm_flags;
758 cfg->fc_nlflags = nlh->nlmsg_flags;
759
760 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
761 cfg->fc_nlinfo.nlh = nlh;
762 cfg->fc_nlinfo.nl_net = net;
763
764 if (cfg->fc_type > RTN_MAX) {
765 NL_SET_ERR_MSG(extack, "Invalid route type");
766 err = -EINVAL;
767 goto errout;
768 }
769
770 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
771 switch (nla_type(attr)) {
772 case RTA_DST:
773 cfg->fc_dst = nla_get_be32(attr);
774 break;
775 case RTA_OIF:
776 cfg->fc_oif = nla_get_u32(attr);
777 break;
778 case RTA_GATEWAY:
779 has_gw = true;
780 cfg->fc_gw4 = nla_get_be32(attr);
781 if (cfg->fc_gw4)
782 cfg->fc_gw_family = AF_INET;
783 break;
784 case RTA_VIA:
785 has_via = true;
786 err = fib_gw_from_via(cfg, attr, extack);
787 if (err)
788 goto errout;
789 break;
790 case RTA_PRIORITY:
791 cfg->fc_priority = nla_get_u32(attr);
792 break;
793 case RTA_PREFSRC:
794 cfg->fc_prefsrc = nla_get_be32(attr);
795 break;
796 case RTA_METRICS:
797 cfg->fc_mx = nla_data(attr);
798 cfg->fc_mx_len = nla_len(attr);
799 break;
800 case RTA_MULTIPATH:
801 err = lwtunnel_valid_encap_type_attr(nla_data(attr),
802 nla_len(attr),
803 extack);
804 if (err < 0)
805 goto errout;
806 cfg->fc_mp = nla_data(attr);
807 cfg->fc_mp_len = nla_len(attr);
808 break;
809 case RTA_FLOW:
810 cfg->fc_flow = nla_get_u32(attr);
811 break;
812 case RTA_TABLE:
813 cfg->fc_table = nla_get_u32(attr);
814 break;
815 case RTA_ENCAP:
816 cfg->fc_encap = attr;
817 break;
818 case RTA_ENCAP_TYPE:
819 cfg->fc_encap_type = nla_get_u16(attr);
820 err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
821 extack);
822 if (err < 0)
823 goto errout;
824 break;
825 case RTA_NH_ID:
826 cfg->fc_nh_id = nla_get_u32(attr);
827 break;
828 }
829 }
830
831 if (cfg->fc_nh_id) {
832 if (cfg->fc_oif || cfg->fc_gw_family ||
833 cfg->fc_encap || cfg->fc_mp) {
834 NL_SET_ERR_MSG(extack,
835 "Nexthop specification and nexthop id are mutually exclusive");
836 return -EINVAL;
837 }
838 }
839
840 if (has_gw && has_via) {
841 NL_SET_ERR_MSG(extack,
842 "Nexthop configuration can not contain both GATEWAY and VIA");
843 return -EINVAL;
844 }
845
846 if (!cfg->fc_table)
847 cfg->fc_table = RT_TABLE_MAIN;
848
849 return 0;
850 errout:
851 return err;
852 }
853
inet_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)854 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
855 struct netlink_ext_ack *extack)
856 {
857 struct net *net = sock_net(skb->sk);
858 struct fib_config cfg;
859 struct fib_table *tb;
860 int err;
861
862 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
863 if (err < 0)
864 goto errout;
865
866 if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
867 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
868 err = -EINVAL;
869 goto errout;
870 }
871
872 tb = fib_get_table(net, cfg.fc_table);
873 if (!tb) {
874 NL_SET_ERR_MSG(extack, "FIB table does not exist");
875 err = -ESRCH;
876 goto errout;
877 }
878
879 err = fib_table_delete(net, tb, &cfg, extack);
880 errout:
881 return err;
882 }
883
inet_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)884 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
885 struct netlink_ext_ack *extack)
886 {
887 struct net *net = sock_net(skb->sk);
888 struct fib_config cfg;
889 struct fib_table *tb;
890 int err;
891
892 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
893 if (err < 0)
894 goto errout;
895
896 tb = fib_new_table(net, cfg.fc_table);
897 if (!tb) {
898 err = -ENOBUFS;
899 goto errout;
900 }
901
902 err = fib_table_insert(net, tb, &cfg, extack);
903 if (!err && cfg.fc_type == RTN_LOCAL)
904 net->ipv4.fib_has_custom_local_routes = true;
905 errout:
906 return err;
907 }
908
ip_valid_fib_dump_req(struct net * net,const struct nlmsghdr * nlh,struct fib_dump_filter * filter,struct netlink_callback * cb)909 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
910 struct fib_dump_filter *filter,
911 struct netlink_callback *cb)
912 {
913 struct netlink_ext_ack *extack = cb->extack;
914 struct nlattr *tb[RTA_MAX + 1];
915 struct rtmsg *rtm;
916 int err, i;
917
918 ASSERT_RTNL();
919
920 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
921 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
922 return -EINVAL;
923 }
924
925 rtm = nlmsg_data(nlh);
926 if (rtm->rtm_dst_len || rtm->rtm_src_len || rtm->rtm_tos ||
927 rtm->rtm_scope) {
928 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
929 return -EINVAL;
930 }
931
932 if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
933 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
934 return -EINVAL;
935 }
936 if (rtm->rtm_flags & RTM_F_CLONED)
937 filter->dump_routes = false;
938 else
939 filter->dump_exceptions = false;
940
941 filter->flags = rtm->rtm_flags;
942 filter->protocol = rtm->rtm_protocol;
943 filter->rt_type = rtm->rtm_type;
944 filter->table_id = rtm->rtm_table;
945
946 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
947 rtm_ipv4_policy, extack);
948 if (err < 0)
949 return err;
950
951 for (i = 0; i <= RTA_MAX; ++i) {
952 int ifindex;
953
954 if (!tb[i])
955 continue;
956
957 switch (i) {
958 case RTA_TABLE:
959 filter->table_id = nla_get_u32(tb[i]);
960 break;
961 case RTA_OIF:
962 ifindex = nla_get_u32(tb[i]);
963 filter->dev = __dev_get_by_index(net, ifindex);
964 if (!filter->dev)
965 return -ENODEV;
966 break;
967 default:
968 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
969 return -EINVAL;
970 }
971 }
972
973 if (filter->flags || filter->protocol || filter->rt_type ||
974 filter->table_id || filter->dev) {
975 filter->filter_set = 1;
976 cb->answer_flags = NLM_F_DUMP_FILTERED;
977 }
978
979 return 0;
980 }
981 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
982
inet_dump_fib(struct sk_buff * skb,struct netlink_callback * cb)983 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
984 {
985 struct fib_dump_filter filter = { .dump_routes = true,
986 .dump_exceptions = true };
987 const struct nlmsghdr *nlh = cb->nlh;
988 struct net *net = sock_net(skb->sk);
989 unsigned int h, s_h;
990 unsigned int e = 0, s_e;
991 struct fib_table *tb;
992 struct hlist_head *head;
993 int dumped = 0, err;
994
995 if (cb->strict_check) {
996 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
997 if (err < 0)
998 return err;
999 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
1000 struct rtmsg *rtm = nlmsg_data(nlh);
1001
1002 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
1003 }
1004
1005 /* ipv4 does not use prefix flag */
1006 if (filter.flags & RTM_F_PREFIX)
1007 return skb->len;
1008
1009 if (filter.table_id) {
1010 tb = fib_get_table(net, filter.table_id);
1011 if (!tb) {
1012 if (rtnl_msg_family(cb->nlh) != PF_INET)
1013 return skb->len;
1014
1015 NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1016 return -ENOENT;
1017 }
1018
1019 rcu_read_lock();
1020 err = fib_table_dump(tb, skb, cb, &filter);
1021 rcu_read_unlock();
1022 return skb->len ? : err;
1023 }
1024
1025 s_h = cb->args[0];
1026 s_e = cb->args[1];
1027
1028 rcu_read_lock();
1029
1030 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1031 e = 0;
1032 head = &net->ipv4.fib_table_hash[h];
1033 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1034 if (e < s_e)
1035 goto next;
1036 if (dumped)
1037 memset(&cb->args[2], 0, sizeof(cb->args) -
1038 2 * sizeof(cb->args[0]));
1039 err = fib_table_dump(tb, skb, cb, &filter);
1040 if (err < 0) {
1041 if (likely(skb->len))
1042 goto out;
1043
1044 goto out_err;
1045 }
1046 dumped = 1;
1047 next:
1048 e++;
1049 }
1050 }
1051 out:
1052 err = skb->len;
1053 out_err:
1054 rcu_read_unlock();
1055
1056 cb->args[1] = e;
1057 cb->args[0] = h;
1058
1059 return err;
1060 }
1061
1062 /* Prepare and feed intra-kernel routing request.
1063 * Really, it should be netlink message, but :-( netlink
1064 * can be not configured, so that we feed it directly
1065 * to fib engine. It is legal, because all events occur
1066 * only when netlink is already locked.
1067 */
fib_magic(int cmd,int type,__be32 dst,int dst_len,struct in_ifaddr * ifa,u32 rt_priority)1068 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1069 struct in_ifaddr *ifa, u32 rt_priority)
1070 {
1071 struct net *net = dev_net(ifa->ifa_dev->dev);
1072 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1073 struct fib_table *tb;
1074 struct fib_config cfg = {
1075 .fc_protocol = RTPROT_KERNEL,
1076 .fc_type = type,
1077 .fc_dst = dst,
1078 .fc_dst_len = dst_len,
1079 .fc_priority = rt_priority,
1080 .fc_prefsrc = ifa->ifa_local,
1081 .fc_oif = ifa->ifa_dev->dev->ifindex,
1082 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1083 .fc_nlinfo = {
1084 .nl_net = net,
1085 },
1086 };
1087
1088 if (!tb_id)
1089 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1090
1091 tb = fib_new_table(net, tb_id);
1092 if (!tb)
1093 return;
1094
1095 cfg.fc_table = tb->tb_id;
1096
1097 if (type != RTN_LOCAL)
1098 cfg.fc_scope = RT_SCOPE_LINK;
1099 else
1100 cfg.fc_scope = RT_SCOPE_HOST;
1101
1102 if (cmd == RTM_NEWROUTE)
1103 fib_table_insert(net, tb, &cfg, NULL);
1104 else
1105 fib_table_delete(net, tb, &cfg, NULL);
1106 }
1107
fib_add_ifaddr(struct in_ifaddr * ifa)1108 void fib_add_ifaddr(struct in_ifaddr *ifa)
1109 {
1110 struct in_device *in_dev = ifa->ifa_dev;
1111 struct net_device *dev = in_dev->dev;
1112 struct in_ifaddr *prim = ifa;
1113 __be32 mask = ifa->ifa_mask;
1114 __be32 addr = ifa->ifa_local;
1115 __be32 prefix = ifa->ifa_address & mask;
1116
1117 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1118 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1119 if (!prim) {
1120 pr_warn("%s: bug: prim == NULL\n", __func__);
1121 return;
1122 }
1123 }
1124
1125 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1126
1127 if (!(dev->flags & IFF_UP))
1128 return;
1129
1130 /* Add broadcast address, if it is explicitly assigned. */
1131 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) {
1132 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1133 prim, 0);
1134 arp_invalidate(dev, ifa->ifa_broadcast, false);
1135 }
1136
1137 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1138 (prefix != addr || ifa->ifa_prefixlen < 32)) {
1139 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1140 fib_magic(RTM_NEWROUTE,
1141 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1142 prefix, ifa->ifa_prefixlen, prim,
1143 ifa->ifa_rt_priority);
1144
1145 /* Add network specific broadcasts, when it takes a sense */
1146 if (ifa->ifa_prefixlen < 31) {
1147 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32,
1148 prim, 0);
1149 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1150 32, prim, 0);
1151 arp_invalidate(dev, prefix | ~mask, false);
1152 }
1153 }
1154 }
1155
fib_modify_prefix_metric(struct in_ifaddr * ifa,u32 new_metric)1156 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1157 {
1158 __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1159 struct in_device *in_dev = ifa->ifa_dev;
1160 struct net_device *dev = in_dev->dev;
1161
1162 if (!(dev->flags & IFF_UP) ||
1163 ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1164 ipv4_is_zeronet(prefix) ||
1165 (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1166 return;
1167
1168 /* add the new */
1169 fib_magic(RTM_NEWROUTE,
1170 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1171 prefix, ifa->ifa_prefixlen, ifa, new_metric);
1172
1173 /* delete the old */
1174 fib_magic(RTM_DELROUTE,
1175 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1176 prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1177 }
1178
1179 /* Delete primary or secondary address.
1180 * Optionally, on secondary address promotion consider the addresses
1181 * from subnet iprim as deleted, even if they are in device list.
1182 * In this case the secondary ifa can be in device list.
1183 */
fib_del_ifaddr(struct in_ifaddr * ifa,struct in_ifaddr * iprim)1184 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1185 {
1186 struct in_device *in_dev = ifa->ifa_dev;
1187 struct net_device *dev = in_dev->dev;
1188 struct in_ifaddr *ifa1;
1189 struct in_ifaddr *prim = ifa, *prim1 = NULL;
1190 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1191 __be32 any = ifa->ifa_address & ifa->ifa_mask;
1192 #define LOCAL_OK 1
1193 #define BRD_OK 2
1194 #define BRD0_OK 4
1195 #define BRD1_OK 8
1196 unsigned int ok = 0;
1197 int subnet = 0; /* Primary network */
1198 int gone = 1; /* Address is missing */
1199 int same_prefsrc = 0; /* Another primary with same IP */
1200
1201 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1202 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1203 if (!prim) {
1204 /* if the device has been deleted, we don't perform
1205 * address promotion
1206 */
1207 if (!in_dev->dead)
1208 pr_warn("%s: bug: prim == NULL\n", __func__);
1209 return;
1210 }
1211 if (iprim && iprim != prim) {
1212 pr_warn("%s: bug: iprim != prim\n", __func__);
1213 return;
1214 }
1215 } else if (!ipv4_is_zeronet(any) &&
1216 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1217 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1218 fib_magic(RTM_DELROUTE,
1219 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1220 any, ifa->ifa_prefixlen, prim, 0);
1221 subnet = 1;
1222 }
1223
1224 if (in_dev->dead)
1225 goto no_promotions;
1226
1227 /* Deletion is more complicated than add.
1228 * We should take care of not to delete too much :-)
1229 *
1230 * Scan address list to be sure that addresses are really gone.
1231 */
1232 rcu_read_lock();
1233 in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1234 if (ifa1 == ifa) {
1235 /* promotion, keep the IP */
1236 gone = 0;
1237 continue;
1238 }
1239 /* Ignore IFAs from our subnet */
1240 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1241 inet_ifa_match(ifa1->ifa_address, iprim))
1242 continue;
1243
1244 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1245 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1246 /* Another address from our subnet? */
1247 if (ifa1->ifa_mask == prim->ifa_mask &&
1248 inet_ifa_match(ifa1->ifa_address, prim))
1249 prim1 = prim;
1250 else {
1251 /* We reached the secondaries, so
1252 * same_prefsrc should be determined.
1253 */
1254 if (!same_prefsrc)
1255 continue;
1256 /* Search new prim1 if ifa1 is not
1257 * using the current prim1
1258 */
1259 if (!prim1 ||
1260 ifa1->ifa_mask != prim1->ifa_mask ||
1261 !inet_ifa_match(ifa1->ifa_address, prim1))
1262 prim1 = inet_ifa_byprefix(in_dev,
1263 ifa1->ifa_address,
1264 ifa1->ifa_mask);
1265 if (!prim1)
1266 continue;
1267 if (prim1->ifa_local != prim->ifa_local)
1268 continue;
1269 }
1270 } else {
1271 if (prim->ifa_local != ifa1->ifa_local)
1272 continue;
1273 prim1 = ifa1;
1274 if (prim != prim1)
1275 same_prefsrc = 1;
1276 }
1277 if (ifa->ifa_local == ifa1->ifa_local)
1278 ok |= LOCAL_OK;
1279 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1280 ok |= BRD_OK;
1281 if (brd == ifa1->ifa_broadcast)
1282 ok |= BRD1_OK;
1283 if (any == ifa1->ifa_broadcast)
1284 ok |= BRD0_OK;
1285 /* primary has network specific broadcasts */
1286 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1287 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1288 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1289
1290 if (!ipv4_is_zeronet(any1)) {
1291 if (ifa->ifa_broadcast == brd1 ||
1292 ifa->ifa_broadcast == any1)
1293 ok |= BRD_OK;
1294 if (brd == brd1 || brd == any1)
1295 ok |= BRD1_OK;
1296 if (any == brd1 || any == any1)
1297 ok |= BRD0_OK;
1298 }
1299 }
1300 }
1301 rcu_read_unlock();
1302
1303 no_promotions:
1304 if (!(ok & BRD_OK))
1305 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1306 prim, 0);
1307 if (subnet && ifa->ifa_prefixlen < 31) {
1308 if (!(ok & BRD1_OK))
1309 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1310 prim, 0);
1311 if (!(ok & BRD0_OK))
1312 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1313 prim, 0);
1314 }
1315 if (!(ok & LOCAL_OK)) {
1316 unsigned int addr_type;
1317
1318 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1319
1320 /* Check, that this local address finally disappeared. */
1321 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1322 ifa->ifa_local);
1323 if (gone && addr_type != RTN_LOCAL) {
1324 /* And the last, but not the least thing.
1325 * We must flush stray FIB entries.
1326 *
1327 * First of all, we scan fib_info list searching
1328 * for stray nexthop entries, then ignite fib_flush.
1329 */
1330 if (fib_sync_down_addr(dev, ifa->ifa_local))
1331 fib_flush(dev_net(dev));
1332 }
1333 }
1334 #undef LOCAL_OK
1335 #undef BRD_OK
1336 #undef BRD0_OK
1337 #undef BRD1_OK
1338 }
1339
nl_fib_lookup(struct net * net,struct fib_result_nl * frn)1340 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1341 {
1342
1343 struct fib_result res;
1344 struct flowi4 fl4 = {
1345 .flowi4_mark = frn->fl_mark,
1346 .daddr = frn->fl_addr,
1347 .flowi4_tos = frn->fl_tos,
1348 .flowi4_scope = frn->fl_scope,
1349 };
1350 struct fib_table *tb;
1351
1352 rcu_read_lock();
1353
1354 tb = fib_get_table(net, frn->tb_id_in);
1355
1356 frn->err = -ENOENT;
1357 if (tb) {
1358 local_bh_disable();
1359
1360 frn->tb_id = tb->tb_id;
1361 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1362
1363 if (!frn->err) {
1364 frn->prefixlen = res.prefixlen;
1365 frn->nh_sel = res.nh_sel;
1366 frn->type = res.type;
1367 frn->scope = res.scope;
1368 }
1369 local_bh_enable();
1370 }
1371
1372 rcu_read_unlock();
1373 }
1374
nl_fib_input(struct sk_buff * skb)1375 static void nl_fib_input(struct sk_buff *skb)
1376 {
1377 struct net *net;
1378 struct fib_result_nl *frn;
1379 struct nlmsghdr *nlh;
1380 u32 portid;
1381
1382 net = sock_net(skb->sk);
1383 nlh = nlmsg_hdr(skb);
1384 if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1385 skb->len < nlh->nlmsg_len ||
1386 nlmsg_len(nlh) < sizeof(*frn))
1387 return;
1388
1389 skb = netlink_skb_clone(skb, GFP_KERNEL);
1390 if (!skb)
1391 return;
1392 nlh = nlmsg_hdr(skb);
1393
1394 frn = (struct fib_result_nl *) nlmsg_data(nlh);
1395 nl_fib_lookup(net, frn);
1396
1397 portid = NETLINK_CB(skb).portid; /* netlink portid */
1398 NETLINK_CB(skb).portid = 0; /* from kernel */
1399 NETLINK_CB(skb).dst_group = 0; /* unicast */
1400 netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
1401 }
1402
nl_fib_lookup_init(struct net * net)1403 static int __net_init nl_fib_lookup_init(struct net *net)
1404 {
1405 struct sock *sk;
1406 struct netlink_kernel_cfg cfg = {
1407 .input = nl_fib_input,
1408 };
1409
1410 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1411 if (!sk)
1412 return -EAFNOSUPPORT;
1413 net->ipv4.fibnl = sk;
1414 return 0;
1415 }
1416
nl_fib_lookup_exit(struct net * net)1417 static void nl_fib_lookup_exit(struct net *net)
1418 {
1419 netlink_kernel_release(net->ipv4.fibnl);
1420 net->ipv4.fibnl = NULL;
1421 }
1422
fib_disable_ip(struct net_device * dev,unsigned long event,bool force)1423 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1424 bool force)
1425 {
1426 if (fib_sync_down_dev(dev, event, force))
1427 fib_flush(dev_net(dev));
1428 else
1429 rt_cache_flush(dev_net(dev));
1430 arp_ifdown(dev);
1431 }
1432
fib_inetaddr_event(struct notifier_block * this,unsigned long event,void * ptr)1433 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1434 {
1435 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1436 struct net_device *dev = ifa->ifa_dev->dev;
1437 struct net *net = dev_net(dev);
1438
1439 switch (event) {
1440 case NETDEV_UP:
1441 fib_add_ifaddr(ifa);
1442 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1443 fib_sync_up(dev, RTNH_F_DEAD);
1444 #endif
1445 atomic_inc(&net->ipv4.dev_addr_genid);
1446 rt_cache_flush(dev_net(dev));
1447 break;
1448 case NETDEV_DOWN:
1449 fib_del_ifaddr(ifa, NULL);
1450 atomic_inc(&net->ipv4.dev_addr_genid);
1451 if (!ifa->ifa_dev->ifa_list) {
1452 /* Last address was deleted from this interface.
1453 * Disable IP.
1454 */
1455 fib_disable_ip(dev, event, true);
1456 } else {
1457 rt_cache_flush(dev_net(dev));
1458 }
1459 break;
1460 }
1461 return NOTIFY_DONE;
1462 }
1463
fib_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1464 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1465 {
1466 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1467 struct netdev_notifier_changeupper_info *upper_info = ptr;
1468 struct netdev_notifier_info_ext *info_ext = ptr;
1469 struct in_device *in_dev;
1470 struct net *net = dev_net(dev);
1471 struct in_ifaddr *ifa;
1472 unsigned int flags;
1473
1474 if (event == NETDEV_UNREGISTER) {
1475 fib_disable_ip(dev, event, true);
1476 rt_flush_dev(dev);
1477 return NOTIFY_DONE;
1478 }
1479
1480 in_dev = __in_dev_get_rtnl(dev);
1481 if (!in_dev)
1482 return NOTIFY_DONE;
1483
1484 switch (event) {
1485 case NETDEV_UP:
1486 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1487 fib_add_ifaddr(ifa);
1488 }
1489 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1490 fib_sync_up(dev, RTNH_F_DEAD);
1491 #endif
1492 atomic_inc(&net->ipv4.dev_addr_genid);
1493 rt_cache_flush(net);
1494 break;
1495 case NETDEV_DOWN:
1496 fib_disable_ip(dev, event, false);
1497 break;
1498 case NETDEV_CHANGE:
1499 flags = dev_get_flags(dev);
1500 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1501 fib_sync_up(dev, RTNH_F_LINKDOWN);
1502 else
1503 fib_sync_down_dev(dev, event, false);
1504 rt_cache_flush(net);
1505 break;
1506 case NETDEV_CHANGEMTU:
1507 fib_sync_mtu(dev, info_ext->ext.mtu);
1508 rt_cache_flush(net);
1509 break;
1510 case NETDEV_CHANGEUPPER:
1511 upper_info = ptr;
1512 /* flush all routes if dev is linked to or unlinked from
1513 * an L3 master device (e.g., VRF)
1514 */
1515 if (upper_info->upper_dev &&
1516 netif_is_l3_master(upper_info->upper_dev))
1517 fib_disable_ip(dev, NETDEV_DOWN, true);
1518 break;
1519 }
1520 return NOTIFY_DONE;
1521 }
1522
1523 static struct notifier_block fib_inetaddr_notifier = {
1524 .notifier_call = fib_inetaddr_event,
1525 };
1526
1527 static struct notifier_block fib_netdev_notifier = {
1528 .notifier_call = fib_netdev_event,
1529 };
1530
ip_fib_net_init(struct net * net)1531 static int __net_init ip_fib_net_init(struct net *net)
1532 {
1533 int err;
1534 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1535
1536 err = fib4_notifier_init(net);
1537 if (err)
1538 return err;
1539
1540 /* Avoid false sharing : Use at least a full cache line */
1541 size = max_t(size_t, size, L1_CACHE_BYTES);
1542
1543 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1544 if (!net->ipv4.fib_table_hash) {
1545 err = -ENOMEM;
1546 goto err_table_hash_alloc;
1547 }
1548
1549 err = fib4_rules_init(net);
1550 if (err < 0)
1551 goto err_rules_init;
1552 return 0;
1553
1554 err_rules_init:
1555 kfree(net->ipv4.fib_table_hash);
1556 err_table_hash_alloc:
1557 fib4_notifier_exit(net);
1558 return err;
1559 }
1560
ip_fib_net_exit(struct net * net)1561 static void ip_fib_net_exit(struct net *net)
1562 {
1563 int i;
1564
1565 rtnl_lock();
1566 #ifdef CONFIG_IP_MULTIPLE_TABLES
1567 RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1568 RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1569 #endif
1570 /* Destroy the tables in reverse order to guarantee that the
1571 * local table, ID 255, is destroyed before the main table, ID
1572 * 254. This is necessary as the local table may contain
1573 * references to data contained in the main table.
1574 */
1575 for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1576 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1577 struct hlist_node *tmp;
1578 struct fib_table *tb;
1579
1580 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1581 hlist_del(&tb->tb_hlist);
1582 fib_table_flush(net, tb, true);
1583 fib_free_table(tb);
1584 }
1585 }
1586
1587 #ifdef CONFIG_IP_MULTIPLE_TABLES
1588 fib4_rules_exit(net);
1589 #endif
1590 rtnl_unlock();
1591 kfree(net->ipv4.fib_table_hash);
1592 fib4_notifier_exit(net);
1593 }
1594
fib_net_init(struct net * net)1595 static int __net_init fib_net_init(struct net *net)
1596 {
1597 int error;
1598
1599 #ifdef CONFIG_IP_ROUTE_CLASSID
1600 atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
1601 #endif
1602 error = ip_fib_net_init(net);
1603 if (error < 0)
1604 goto out;
1605 error = nl_fib_lookup_init(net);
1606 if (error < 0)
1607 goto out_nlfl;
1608 error = fib_proc_init(net);
1609 if (error < 0)
1610 goto out_proc;
1611 out:
1612 return error;
1613
1614 out_proc:
1615 nl_fib_lookup_exit(net);
1616 out_nlfl:
1617 ip_fib_net_exit(net);
1618 goto out;
1619 }
1620
fib_net_exit(struct net * net)1621 static void __net_exit fib_net_exit(struct net *net)
1622 {
1623 fib_proc_exit(net);
1624 nl_fib_lookup_exit(net);
1625 ip_fib_net_exit(net);
1626 }
1627
1628 static struct pernet_operations fib_net_ops = {
1629 .init = fib_net_init,
1630 .exit = fib_net_exit,
1631 };
1632
ip_fib_init(void)1633 void __init ip_fib_init(void)
1634 {
1635 fib_trie_init();
1636
1637 register_pernet_subsys(&fib_net_ops);
1638
1639 register_netdevice_notifier(&fib_netdev_notifier);
1640 register_inetaddr_notifier(&fib_inetaddr_notifier);
1641
1642 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1643 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1644 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1645 }
1646