1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: FIB frontend.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/module.h>
13 #include <linux/uaccess.h>
14 #include <linux/bitops.h>
15 #include <linux/capability.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/string.h>
20 #include <linux/socket.h>
21 #include <linux/sockios.h>
22 #include <linux/errno.h>
23 #include <linux/in.h>
24 #include <linux/inet.h>
25 #include <linux/inetdevice.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_addr.h>
28 #include <linux/if_arp.h>
29 #include <linux/skbuff.h>
30 #include <linux/cache.h>
31 #include <linux/init.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34
35 #include <net/inet_dscp.h>
36 #include <net/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/arp.h>
42 #include <net/ip_fib.h>
43 #include <net/nexthop.h>
44 #include <net/rtnetlink.h>
45 #include <net/xfrm.h>
46 #include <net/l3mdev.h>
47 #include <net/lwtunnel.h>
48 #include <trace/events/fib.h>
49
50 #ifndef CONFIG_IP_MULTIPLE_TABLES
51
fib4_rules_init(struct net * net)52 static int __net_init fib4_rules_init(struct net *net)
53 {
54 struct fib_table *local_table, *main_table;
55
56 main_table = fib_trie_table(RT_TABLE_MAIN, NULL);
57 if (!main_table)
58 return -ENOMEM;
59
60 local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
61 if (!local_table)
62 goto fail;
63
64 hlist_add_head_rcu(&local_table->tb_hlist,
65 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
66 hlist_add_head_rcu(&main_table->tb_hlist,
67 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
68 return 0;
69
70 fail:
71 fib_free_table(main_table);
72 return -ENOMEM;
73 }
74 #else
75
fib_new_table(struct net * net,u32 id)76 struct fib_table *fib_new_table(struct net *net, u32 id)
77 {
78 struct fib_table *tb, *alias = NULL;
79 unsigned int h;
80
81 if (id == 0)
82 id = RT_TABLE_MAIN;
83 tb = fib_get_table(net, id);
84 if (tb)
85 return tb;
86
87 if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
88 alias = fib_new_table(net, RT_TABLE_MAIN);
89
90 tb = fib_trie_table(id, alias);
91 if (!tb)
92 return NULL;
93
94 switch (id) {
95 case RT_TABLE_MAIN:
96 rcu_assign_pointer(net->ipv4.fib_main, tb);
97 break;
98 case RT_TABLE_DEFAULT:
99 rcu_assign_pointer(net->ipv4.fib_default, tb);
100 break;
101 default:
102 break;
103 }
104
105 h = id & (FIB_TABLE_HASHSZ - 1);
106 hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
107 return tb;
108 }
109 EXPORT_SYMBOL_GPL(fib_new_table);
110
111 /* caller must hold either rtnl or rcu read lock */
fib_get_table(struct net * net,u32 id)112 struct fib_table *fib_get_table(struct net *net, u32 id)
113 {
114 struct fib_table *tb;
115 struct hlist_head *head;
116 unsigned int h;
117
118 if (id == 0)
119 id = RT_TABLE_MAIN;
120 h = id & (FIB_TABLE_HASHSZ - 1);
121
122 head = &net->ipv4.fib_table_hash[h];
123 hlist_for_each_entry_rcu(tb, head, tb_hlist,
124 lockdep_rtnl_is_held()) {
125 if (tb->tb_id == id)
126 return tb;
127 }
128 return NULL;
129 }
130 #endif /* CONFIG_IP_MULTIPLE_TABLES */
131
fib_replace_table(struct net * net,struct fib_table * old,struct fib_table * new)132 static void fib_replace_table(struct net *net, struct fib_table *old,
133 struct fib_table *new)
134 {
135 #ifdef CONFIG_IP_MULTIPLE_TABLES
136 switch (new->tb_id) {
137 case RT_TABLE_MAIN:
138 rcu_assign_pointer(net->ipv4.fib_main, new);
139 break;
140 case RT_TABLE_DEFAULT:
141 rcu_assign_pointer(net->ipv4.fib_default, new);
142 break;
143 default:
144 break;
145 }
146
147 #endif
148 /* replace the old table in the hlist */
149 hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
150 }
151
fib_unmerge(struct net * net)152 int fib_unmerge(struct net *net)
153 {
154 struct fib_table *old, *new, *main_table;
155
156 /* attempt to fetch local table if it has been allocated */
157 old = fib_get_table(net, RT_TABLE_LOCAL);
158 if (!old)
159 return 0;
160
161 new = fib_trie_unmerge(old);
162 if (!new)
163 return -ENOMEM;
164
165 /* table is already unmerged */
166 if (new == old)
167 return 0;
168
169 /* replace merged table with clean table */
170 fib_replace_table(net, old, new);
171 fib_free_table(old);
172
173 /* attempt to fetch main table if it has been allocated */
174 main_table = fib_get_table(net, RT_TABLE_MAIN);
175 if (!main_table)
176 return 0;
177
178 /* flush local entries from main table */
179 fib_table_flush_external(main_table);
180
181 return 0;
182 }
183
fib_flush(struct net * net)184 void fib_flush(struct net *net)
185 {
186 int flushed = 0;
187 unsigned int h;
188
189 for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
190 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
191 struct hlist_node *tmp;
192 struct fib_table *tb;
193
194 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
195 flushed += fib_table_flush(net, tb, false);
196 }
197
198 if (flushed)
199 rt_cache_flush(net);
200 }
201
202 /*
203 * Find address type as if only "dev" was present in the system. If
204 * on_dev is NULL then all interfaces are taken into consideration.
205 */
__inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr,u32 tb_id)206 static inline unsigned int __inet_dev_addr_type(struct net *net,
207 const struct net_device *dev,
208 __be32 addr, u32 tb_id)
209 {
210 struct flowi4 fl4 = { .daddr = addr };
211 struct fib_result res;
212 unsigned int ret = RTN_BROADCAST;
213 struct fib_table *table;
214
215 if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
216 return RTN_BROADCAST;
217 if (ipv4_is_multicast(addr))
218 return RTN_MULTICAST;
219
220 rcu_read_lock();
221
222 table = fib_get_table(net, tb_id);
223 if (table) {
224 ret = RTN_UNICAST;
225 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
226 struct fib_nh_common *nhc = fib_info_nhc(res.fi, 0);
227
228 if (!dev || dev == nhc->nhc_dev)
229 ret = res.type;
230 }
231 }
232
233 rcu_read_unlock();
234 return ret;
235 }
236
inet_addr_type_table(struct net * net,__be32 addr,u32 tb_id)237 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
238 {
239 return __inet_dev_addr_type(net, NULL, addr, tb_id);
240 }
241 EXPORT_SYMBOL(inet_addr_type_table);
242
inet_addr_type(struct net * net,__be32 addr)243 unsigned int inet_addr_type(struct net *net, __be32 addr)
244 {
245 return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
246 }
247 EXPORT_SYMBOL(inet_addr_type);
248
inet_dev_addr_type(struct net * net,const struct net_device * dev,__be32 addr)249 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
250 __be32 addr)
251 {
252 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
253
254 return __inet_dev_addr_type(net, dev, addr, rt_table);
255 }
256 EXPORT_SYMBOL(inet_dev_addr_type);
257
258 /* inet_addr_type with dev == NULL but using the table from a dev
259 * if one is associated
260 */
inet_addr_type_dev_table(struct net * net,const struct net_device * dev,__be32 addr)261 unsigned int inet_addr_type_dev_table(struct net *net,
262 const struct net_device *dev,
263 __be32 addr)
264 {
265 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
266
267 return __inet_dev_addr_type(net, NULL, addr, rt_table);
268 }
269 EXPORT_SYMBOL(inet_addr_type_dev_table);
270
fib_compute_spec_dst(struct sk_buff * skb)271 __be32 fib_compute_spec_dst(struct sk_buff *skb)
272 {
273 struct net_device *dev = skb->dev;
274 struct in_device *in_dev;
275 struct fib_result res;
276 struct rtable *rt;
277 struct net *net;
278 int scope;
279
280 rt = skb_rtable(skb);
281 if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
282 RTCF_LOCAL)
283 return ip_hdr(skb)->daddr;
284
285 in_dev = __in_dev_get_rcu(dev);
286
287 net = dev_net(dev);
288
289 scope = RT_SCOPE_UNIVERSE;
290 if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
291 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
292 struct flowi4 fl4 = {
293 .flowi4_iif = LOOPBACK_IFINDEX,
294 .flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev),
295 .daddr = ip_hdr(skb)->saddr,
296 .flowi4_tos = ip_hdr(skb)->tos & IPTOS_RT_MASK,
297 .flowi4_scope = scope,
298 .flowi4_mark = vmark ? skb->mark : 0,
299 };
300 if (!fib_lookup(net, &fl4, &res, 0))
301 return fib_result_prefsrc(net, &res);
302 } else {
303 scope = RT_SCOPE_LINK;
304 }
305
306 return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
307 }
308
fib_info_nh_uses_dev(struct fib_info * fi,const struct net_device * dev)309 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
310 {
311 bool dev_match = false;
312 #ifdef CONFIG_IP_ROUTE_MULTIPATH
313 if (unlikely(fi->nh)) {
314 dev_match = nexthop_uses_dev(fi->nh, dev);
315 } else {
316 int ret;
317
318 for (ret = 0; ret < fib_info_num_path(fi); ret++) {
319 const struct fib_nh_common *nhc = fib_info_nhc(fi, ret);
320
321 if (nhc_l3mdev_matches_dev(nhc, dev)) {
322 dev_match = true;
323 break;
324 }
325 }
326 }
327 #else
328 if (fib_info_nhc(fi, 0)->nhc_dev == dev)
329 dev_match = true;
330 #endif
331
332 return dev_match;
333 }
334 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
335
336 /* Given (packet source, input interface) and optional (dst, oif, tos):
337 * - (main) check, that source is valid i.e. not broadcast or our local
338 * address.
339 * - figure out what "logical" interface this packet arrived
340 * and calculate "specific destination" address.
341 * - check, that packet arrived from expected physical interface.
342 * called with rcu_read_lock()
343 */
__fib_validate_source(struct sk_buff * skb,__be32 src,__be32 dst,u8 tos,int oif,struct net_device * dev,int rpf,struct in_device * idev,u32 * itag)344 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
345 u8 tos, int oif, struct net_device *dev,
346 int rpf, struct in_device *idev, u32 *itag)
347 {
348 struct net *net = dev_net(dev);
349 struct flow_keys flkeys;
350 int ret, no_addr;
351 struct fib_result res;
352 struct flowi4 fl4;
353 bool dev_match;
354
355 fl4.flowi4_oif = 0;
356 fl4.flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev);
357 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
358 fl4.daddr = src;
359 fl4.saddr = dst;
360 fl4.flowi4_tos = tos;
361 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
362 fl4.flowi4_tun_key.tun_id = 0;
363 fl4.flowi4_flags = 0;
364 fl4.flowi4_uid = sock_net_uid(net, NULL);
365 fl4.flowi4_multipath_hash = 0;
366
367 no_addr = idev->ifa_list == NULL;
368
369 fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
370 if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
371 fl4.flowi4_proto = 0;
372 fl4.fl4_sport = 0;
373 fl4.fl4_dport = 0;
374 } else {
375 swap(fl4.fl4_sport, fl4.fl4_dport);
376 }
377
378 if (fib_lookup(net, &fl4, &res, 0))
379 goto last_resort;
380 if (res.type != RTN_UNICAST &&
381 (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
382 goto e_inval;
383 fib_combine_itag(itag, &res);
384
385 dev_match = fib_info_nh_uses_dev(res.fi, dev);
386 /* This is not common, loopback packets retain skb_dst so normally they
387 * would not even hit this slow path.
388 */
389 dev_match = dev_match || (res.type == RTN_LOCAL &&
390 dev == net->loopback_dev);
391 if (dev_match) {
392 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
393 return ret;
394 }
395 if (no_addr)
396 goto last_resort;
397 if (rpf == 1)
398 goto e_rpf;
399 fl4.flowi4_oif = dev->ifindex;
400
401 ret = 0;
402 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
403 if (res.type == RTN_UNICAST)
404 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
405 }
406 return ret;
407
408 last_resort:
409 if (rpf)
410 goto e_rpf;
411 *itag = 0;
412 return 0;
413
414 e_inval:
415 return -EINVAL;
416 e_rpf:
417 return -EXDEV;
418 }
419
420 /* Ignore rp_filter for packets protected by IPsec. */
fib_validate_source(struct sk_buff * skb,__be32 src,__be32 dst,u8 tos,int oif,struct net_device * dev,struct in_device * idev,u32 * itag)421 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
422 u8 tos, int oif, struct net_device *dev,
423 struct in_device *idev, u32 *itag)
424 {
425 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
426 struct net *net = dev_net(dev);
427
428 if (!r && !fib_num_tclassid_users(net) &&
429 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
430 if (IN_DEV_ACCEPT_LOCAL(idev))
431 goto ok;
432 /* with custom local routes in place, checking local addresses
433 * only will be too optimistic, with custom rules, checking
434 * local addresses only can be too strict, e.g. due to vrf
435 */
436 if (net->ipv4.fib_has_custom_local_routes ||
437 fib4_has_custom_rules(net))
438 goto full_check;
439 /* Within the same container, it is regarded as a martian source,
440 * and the same host but different containers are not.
441 */
442 if (inet_lookup_ifaddr_rcu(net, src))
443 return -EINVAL;
444
445 ok:
446 *itag = 0;
447 return 0;
448 }
449
450 full_check:
451 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
452 }
453
sk_extract_addr(struct sockaddr * addr)454 static inline __be32 sk_extract_addr(struct sockaddr *addr)
455 {
456 return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
457 }
458
put_rtax(struct nlattr * mx,int len,int type,u32 value)459 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
460 {
461 struct nlattr *nla;
462
463 nla = (struct nlattr *) ((char *) mx + len);
464 nla->nla_type = type;
465 nla->nla_len = nla_attr_size(4);
466 *(u32 *) nla_data(nla) = value;
467
468 return len + nla_total_size(4);
469 }
470
rtentry_to_fib_config(struct net * net,int cmd,struct rtentry * rt,struct fib_config * cfg)471 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
472 struct fib_config *cfg)
473 {
474 __be32 addr;
475 int plen;
476
477 memset(cfg, 0, sizeof(*cfg));
478 cfg->fc_nlinfo.nl_net = net;
479
480 if (rt->rt_dst.sa_family != AF_INET)
481 return -EAFNOSUPPORT;
482
483 /*
484 * Check mask for validity:
485 * a) it must be contiguous.
486 * b) destination must have all host bits clear.
487 * c) if application forgot to set correct family (AF_INET),
488 * reject request unless it is absolutely clear i.e.
489 * both family and mask are zero.
490 */
491 plen = 32;
492 addr = sk_extract_addr(&rt->rt_dst);
493 if (!(rt->rt_flags & RTF_HOST)) {
494 __be32 mask = sk_extract_addr(&rt->rt_genmask);
495
496 if (rt->rt_genmask.sa_family != AF_INET) {
497 if (mask || rt->rt_genmask.sa_family)
498 return -EAFNOSUPPORT;
499 }
500
501 if (bad_mask(mask, addr))
502 return -EINVAL;
503
504 plen = inet_mask_len(mask);
505 }
506
507 cfg->fc_dst_len = plen;
508 cfg->fc_dst = addr;
509
510 if (cmd != SIOCDELRT) {
511 cfg->fc_nlflags = NLM_F_CREATE;
512 cfg->fc_protocol = RTPROT_BOOT;
513 }
514
515 if (rt->rt_metric)
516 cfg->fc_priority = rt->rt_metric - 1;
517
518 if (rt->rt_flags & RTF_REJECT) {
519 cfg->fc_scope = RT_SCOPE_HOST;
520 cfg->fc_type = RTN_UNREACHABLE;
521 return 0;
522 }
523
524 cfg->fc_scope = RT_SCOPE_NOWHERE;
525 cfg->fc_type = RTN_UNICAST;
526
527 if (rt->rt_dev) {
528 char *colon;
529 struct net_device *dev;
530 char devname[IFNAMSIZ];
531
532 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
533 return -EFAULT;
534
535 devname[IFNAMSIZ-1] = 0;
536 colon = strchr(devname, ':');
537 if (colon)
538 *colon = 0;
539 dev = __dev_get_by_name(net, devname);
540 if (!dev)
541 return -ENODEV;
542 cfg->fc_oif = dev->ifindex;
543 cfg->fc_table = l3mdev_fib_table(dev);
544 if (colon) {
545 const struct in_ifaddr *ifa;
546 struct in_device *in_dev;
547
548 in_dev = __in_dev_get_rtnl(dev);
549 if (!in_dev)
550 return -ENODEV;
551
552 *colon = ':';
553
554 rcu_read_lock();
555 in_dev_for_each_ifa_rcu(ifa, in_dev) {
556 if (strcmp(ifa->ifa_label, devname) == 0)
557 break;
558 }
559 rcu_read_unlock();
560
561 if (!ifa)
562 return -ENODEV;
563 cfg->fc_prefsrc = ifa->ifa_local;
564 }
565 }
566
567 addr = sk_extract_addr(&rt->rt_gateway);
568 if (rt->rt_gateway.sa_family == AF_INET && addr) {
569 unsigned int addr_type;
570
571 cfg->fc_gw4 = addr;
572 cfg->fc_gw_family = AF_INET;
573 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
574 if (rt->rt_flags & RTF_GATEWAY &&
575 addr_type == RTN_UNICAST)
576 cfg->fc_scope = RT_SCOPE_UNIVERSE;
577 }
578
579 if (!cfg->fc_table)
580 cfg->fc_table = RT_TABLE_MAIN;
581
582 if (cmd == SIOCDELRT)
583 return 0;
584
585 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
586 return -EINVAL;
587
588 if (cfg->fc_scope == RT_SCOPE_NOWHERE)
589 cfg->fc_scope = RT_SCOPE_LINK;
590
591 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
592 struct nlattr *mx;
593 int len = 0;
594
595 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
596 if (!mx)
597 return -ENOMEM;
598
599 if (rt->rt_flags & RTF_MTU)
600 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
601
602 if (rt->rt_flags & RTF_WINDOW)
603 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
604
605 if (rt->rt_flags & RTF_IRTT)
606 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
607
608 cfg->fc_mx = mx;
609 cfg->fc_mx_len = len;
610 }
611
612 return 0;
613 }
614
615 /*
616 * Handle IP routing ioctl calls.
617 * These are used to manipulate the routing tables
618 */
ip_rt_ioctl(struct net * net,unsigned int cmd,struct rtentry * rt)619 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
620 {
621 struct fib_config cfg;
622 int err;
623
624 switch (cmd) {
625 case SIOCADDRT: /* Add a route */
626 case SIOCDELRT: /* Delete a route */
627 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
628 return -EPERM;
629
630 rtnl_lock();
631 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
632 if (err == 0) {
633 struct fib_table *tb;
634
635 if (cmd == SIOCDELRT) {
636 tb = fib_get_table(net, cfg.fc_table);
637 if (tb)
638 err = fib_table_delete(net, tb, &cfg,
639 NULL);
640 else
641 err = -ESRCH;
642 } else {
643 tb = fib_new_table(net, cfg.fc_table);
644 if (tb)
645 err = fib_table_insert(net, tb,
646 &cfg, NULL);
647 else
648 err = -ENOBUFS;
649 }
650
651 /* allocated by rtentry_to_fib_config() */
652 kfree(cfg.fc_mx);
653 }
654 rtnl_unlock();
655 return err;
656 }
657 return -EINVAL;
658 }
659
660 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
661 [RTA_UNSPEC] = { .strict_start_type = RTA_DPORT + 1 },
662 [RTA_DST] = { .type = NLA_U32 },
663 [RTA_SRC] = { .type = NLA_U32 },
664 [RTA_IIF] = { .type = NLA_U32 },
665 [RTA_OIF] = { .type = NLA_U32 },
666 [RTA_GATEWAY] = { .type = NLA_U32 },
667 [RTA_PRIORITY] = { .type = NLA_U32 },
668 [RTA_PREFSRC] = { .type = NLA_U32 },
669 [RTA_METRICS] = { .type = NLA_NESTED },
670 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
671 [RTA_FLOW] = { .type = NLA_U32 },
672 [RTA_ENCAP_TYPE] = { .type = NLA_U16 },
673 [RTA_ENCAP] = { .type = NLA_NESTED },
674 [RTA_UID] = { .type = NLA_U32 },
675 [RTA_MARK] = { .type = NLA_U32 },
676 [RTA_TABLE] = { .type = NLA_U32 },
677 [RTA_IP_PROTO] = { .type = NLA_U8 },
678 [RTA_SPORT] = { .type = NLA_U16 },
679 [RTA_DPORT] = { .type = NLA_U16 },
680 [RTA_NH_ID] = { .type = NLA_U32 },
681 };
682
fib_gw_from_via(struct fib_config * cfg,struct nlattr * nla,struct netlink_ext_ack * extack)683 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
684 struct netlink_ext_ack *extack)
685 {
686 struct rtvia *via;
687 int alen;
688
689 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
690 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
691 return -EINVAL;
692 }
693
694 via = nla_data(nla);
695 alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
696
697 switch (via->rtvia_family) {
698 case AF_INET:
699 if (alen != sizeof(__be32)) {
700 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
701 return -EINVAL;
702 }
703 cfg->fc_gw_family = AF_INET;
704 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
705 break;
706 case AF_INET6:
707 #if IS_ENABLED(CONFIG_IPV6)
708 if (alen != sizeof(struct in6_addr)) {
709 NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
710 return -EINVAL;
711 }
712 cfg->fc_gw_family = AF_INET6;
713 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
714 #else
715 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
716 return -EINVAL;
717 #endif
718 break;
719 default:
720 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
721 return -EINVAL;
722 }
723
724 return 0;
725 }
726
rtm_to_fib_config(struct net * net,struct sk_buff * skb,struct nlmsghdr * nlh,struct fib_config * cfg,struct netlink_ext_ack * extack)727 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
728 struct nlmsghdr *nlh, struct fib_config *cfg,
729 struct netlink_ext_ack *extack)
730 {
731 bool has_gw = false, has_via = false;
732 struct nlattr *attr;
733 int err, remaining;
734 struct rtmsg *rtm;
735
736 err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
737 rtm_ipv4_policy, extack);
738 if (err < 0)
739 goto errout;
740
741 memset(cfg, 0, sizeof(*cfg));
742
743 rtm = nlmsg_data(nlh);
744
745 if (!inet_validate_dscp(rtm->rtm_tos)) {
746 NL_SET_ERR_MSG(extack,
747 "Invalid dsfield (tos): ECN bits must be 0");
748 err = -EINVAL;
749 goto errout;
750 }
751 cfg->fc_dscp = inet_dsfield_to_dscp(rtm->rtm_tos);
752
753 cfg->fc_dst_len = rtm->rtm_dst_len;
754 cfg->fc_table = rtm->rtm_table;
755 cfg->fc_protocol = rtm->rtm_protocol;
756 cfg->fc_scope = rtm->rtm_scope;
757 cfg->fc_type = rtm->rtm_type;
758 cfg->fc_flags = rtm->rtm_flags;
759 cfg->fc_nlflags = nlh->nlmsg_flags;
760
761 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
762 cfg->fc_nlinfo.nlh = nlh;
763 cfg->fc_nlinfo.nl_net = net;
764
765 if (cfg->fc_type > RTN_MAX) {
766 NL_SET_ERR_MSG(extack, "Invalid route type");
767 err = -EINVAL;
768 goto errout;
769 }
770
771 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
772 switch (nla_type(attr)) {
773 case RTA_DST:
774 cfg->fc_dst = nla_get_be32(attr);
775 break;
776 case RTA_OIF:
777 cfg->fc_oif = nla_get_u32(attr);
778 break;
779 case RTA_GATEWAY:
780 has_gw = true;
781 cfg->fc_gw4 = nla_get_be32(attr);
782 if (cfg->fc_gw4)
783 cfg->fc_gw_family = AF_INET;
784 break;
785 case RTA_VIA:
786 has_via = true;
787 err = fib_gw_from_via(cfg, attr, extack);
788 if (err)
789 goto errout;
790 break;
791 case RTA_PRIORITY:
792 cfg->fc_priority = nla_get_u32(attr);
793 break;
794 case RTA_PREFSRC:
795 cfg->fc_prefsrc = nla_get_be32(attr);
796 break;
797 case RTA_METRICS:
798 cfg->fc_mx = nla_data(attr);
799 cfg->fc_mx_len = nla_len(attr);
800 break;
801 case RTA_MULTIPATH:
802 err = lwtunnel_valid_encap_type_attr(nla_data(attr),
803 nla_len(attr),
804 extack);
805 if (err < 0)
806 goto errout;
807 cfg->fc_mp = nla_data(attr);
808 cfg->fc_mp_len = nla_len(attr);
809 break;
810 case RTA_FLOW:
811 cfg->fc_flow = nla_get_u32(attr);
812 break;
813 case RTA_TABLE:
814 cfg->fc_table = nla_get_u32(attr);
815 break;
816 case RTA_ENCAP:
817 cfg->fc_encap = attr;
818 break;
819 case RTA_ENCAP_TYPE:
820 cfg->fc_encap_type = nla_get_u16(attr);
821 err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
822 extack);
823 if (err < 0)
824 goto errout;
825 break;
826 case RTA_NH_ID:
827 cfg->fc_nh_id = nla_get_u32(attr);
828 break;
829 }
830 }
831
832 if (cfg->fc_dst_len > 32) {
833 NL_SET_ERR_MSG(extack, "Invalid prefix length");
834 err = -EINVAL;
835 goto errout;
836 }
837
838 if (cfg->fc_dst_len < 32 && (ntohl(cfg->fc_dst) << cfg->fc_dst_len)) {
839 NL_SET_ERR_MSG(extack, "Invalid prefix for given prefix length");
840 err = -EINVAL;
841 goto errout;
842 }
843
844 if (cfg->fc_nh_id) {
845 if (cfg->fc_oif || cfg->fc_gw_family ||
846 cfg->fc_encap || cfg->fc_mp) {
847 NL_SET_ERR_MSG(extack,
848 "Nexthop specification and nexthop id are mutually exclusive");
849 err = -EINVAL;
850 goto errout;
851 }
852 }
853
854 if (has_gw && has_via) {
855 NL_SET_ERR_MSG(extack,
856 "Nexthop configuration can not contain both GATEWAY and VIA");
857 err = -EINVAL;
858 goto errout;
859 }
860
861 if (!cfg->fc_table)
862 cfg->fc_table = RT_TABLE_MAIN;
863
864 return 0;
865 errout:
866 return err;
867 }
868
inet_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)869 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
870 struct netlink_ext_ack *extack)
871 {
872 struct net *net = sock_net(skb->sk);
873 struct fib_config cfg;
874 struct fib_table *tb;
875 int err;
876
877 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
878 if (err < 0)
879 goto errout;
880
881 if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
882 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
883 err = -EINVAL;
884 goto errout;
885 }
886
887 tb = fib_get_table(net, cfg.fc_table);
888 if (!tb) {
889 NL_SET_ERR_MSG(extack, "FIB table does not exist");
890 err = -ESRCH;
891 goto errout;
892 }
893
894 err = fib_table_delete(net, tb, &cfg, extack);
895 errout:
896 return err;
897 }
898
inet_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)899 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
900 struct netlink_ext_ack *extack)
901 {
902 struct net *net = sock_net(skb->sk);
903 struct fib_config cfg;
904 struct fib_table *tb;
905 int err;
906
907 err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
908 if (err < 0)
909 goto errout;
910
911 tb = fib_new_table(net, cfg.fc_table);
912 if (!tb) {
913 err = -ENOBUFS;
914 goto errout;
915 }
916
917 err = fib_table_insert(net, tb, &cfg, extack);
918 if (!err && cfg.fc_type == RTN_LOCAL)
919 net->ipv4.fib_has_custom_local_routes = true;
920 errout:
921 return err;
922 }
923
ip_valid_fib_dump_req(struct net * net,const struct nlmsghdr * nlh,struct fib_dump_filter * filter,struct netlink_callback * cb)924 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
925 struct fib_dump_filter *filter,
926 struct netlink_callback *cb)
927 {
928 struct netlink_ext_ack *extack = cb->extack;
929 struct nlattr *tb[RTA_MAX + 1];
930 struct rtmsg *rtm;
931 int err, i;
932
933 ASSERT_RTNL();
934
935 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
936 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
937 return -EINVAL;
938 }
939
940 rtm = nlmsg_data(nlh);
941 if (rtm->rtm_dst_len || rtm->rtm_src_len || rtm->rtm_tos ||
942 rtm->rtm_scope) {
943 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
944 return -EINVAL;
945 }
946
947 if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
948 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
949 return -EINVAL;
950 }
951 if (rtm->rtm_flags & RTM_F_CLONED)
952 filter->dump_routes = false;
953 else
954 filter->dump_exceptions = false;
955
956 filter->flags = rtm->rtm_flags;
957 filter->protocol = rtm->rtm_protocol;
958 filter->rt_type = rtm->rtm_type;
959 filter->table_id = rtm->rtm_table;
960
961 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
962 rtm_ipv4_policy, extack);
963 if (err < 0)
964 return err;
965
966 for (i = 0; i <= RTA_MAX; ++i) {
967 int ifindex;
968
969 if (!tb[i])
970 continue;
971
972 switch (i) {
973 case RTA_TABLE:
974 filter->table_id = nla_get_u32(tb[i]);
975 break;
976 case RTA_OIF:
977 ifindex = nla_get_u32(tb[i]);
978 filter->dev = __dev_get_by_index(net, ifindex);
979 if (!filter->dev)
980 return -ENODEV;
981 break;
982 default:
983 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
984 return -EINVAL;
985 }
986 }
987
988 if (filter->flags || filter->protocol || filter->rt_type ||
989 filter->table_id || filter->dev) {
990 filter->filter_set = 1;
991 cb->answer_flags = NLM_F_DUMP_FILTERED;
992 }
993
994 return 0;
995 }
996 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
997
inet_dump_fib(struct sk_buff * skb,struct netlink_callback * cb)998 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
999 {
1000 struct fib_dump_filter filter = { .dump_routes = true,
1001 .dump_exceptions = true };
1002 const struct nlmsghdr *nlh = cb->nlh;
1003 struct net *net = sock_net(skb->sk);
1004 unsigned int h, s_h;
1005 unsigned int e = 0, s_e;
1006 struct fib_table *tb;
1007 struct hlist_head *head;
1008 int dumped = 0, err;
1009
1010 if (cb->strict_check) {
1011 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
1012 if (err < 0)
1013 return err;
1014 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
1015 struct rtmsg *rtm = nlmsg_data(nlh);
1016
1017 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
1018 }
1019
1020 /* ipv4 does not use prefix flag */
1021 if (filter.flags & RTM_F_PREFIX)
1022 return skb->len;
1023
1024 if (filter.table_id) {
1025 tb = fib_get_table(net, filter.table_id);
1026 if (!tb) {
1027 if (rtnl_msg_family(cb->nlh) != PF_INET)
1028 return skb->len;
1029
1030 NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1031 return -ENOENT;
1032 }
1033
1034 rcu_read_lock();
1035 err = fib_table_dump(tb, skb, cb, &filter);
1036 rcu_read_unlock();
1037 return skb->len ? : err;
1038 }
1039
1040 s_h = cb->args[0];
1041 s_e = cb->args[1];
1042
1043 rcu_read_lock();
1044
1045 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1046 e = 0;
1047 head = &net->ipv4.fib_table_hash[h];
1048 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1049 if (e < s_e)
1050 goto next;
1051 if (dumped)
1052 memset(&cb->args[2], 0, sizeof(cb->args) -
1053 2 * sizeof(cb->args[0]));
1054 err = fib_table_dump(tb, skb, cb, &filter);
1055 if (err < 0) {
1056 if (likely(skb->len))
1057 goto out;
1058
1059 goto out_err;
1060 }
1061 dumped = 1;
1062 next:
1063 e++;
1064 }
1065 }
1066 out:
1067 err = skb->len;
1068 out_err:
1069 rcu_read_unlock();
1070
1071 cb->args[1] = e;
1072 cb->args[0] = h;
1073
1074 return err;
1075 }
1076
1077 /* Prepare and feed intra-kernel routing request.
1078 * Really, it should be netlink message, but :-( netlink
1079 * can be not configured, so that we feed it directly
1080 * to fib engine. It is legal, because all events occur
1081 * only when netlink is already locked.
1082 */
fib_magic(int cmd,int type,__be32 dst,int dst_len,struct in_ifaddr * ifa,u32 rt_priority)1083 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1084 struct in_ifaddr *ifa, u32 rt_priority)
1085 {
1086 struct net *net = dev_net(ifa->ifa_dev->dev);
1087 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1088 struct fib_table *tb;
1089 struct fib_config cfg = {
1090 .fc_protocol = RTPROT_KERNEL,
1091 .fc_type = type,
1092 .fc_dst = dst,
1093 .fc_dst_len = dst_len,
1094 .fc_priority = rt_priority,
1095 .fc_prefsrc = ifa->ifa_local,
1096 .fc_oif = ifa->ifa_dev->dev->ifindex,
1097 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1098 .fc_nlinfo = {
1099 .nl_net = net,
1100 },
1101 };
1102
1103 if (!tb_id)
1104 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1105
1106 tb = fib_new_table(net, tb_id);
1107 if (!tb)
1108 return;
1109
1110 cfg.fc_table = tb->tb_id;
1111
1112 if (type != RTN_LOCAL)
1113 cfg.fc_scope = RT_SCOPE_LINK;
1114 else
1115 cfg.fc_scope = RT_SCOPE_HOST;
1116
1117 if (cmd == RTM_NEWROUTE)
1118 fib_table_insert(net, tb, &cfg, NULL);
1119 else
1120 fib_table_delete(net, tb, &cfg, NULL);
1121 }
1122
fib_add_ifaddr(struct in_ifaddr * ifa)1123 void fib_add_ifaddr(struct in_ifaddr *ifa)
1124 {
1125 struct in_device *in_dev = ifa->ifa_dev;
1126 struct net_device *dev = in_dev->dev;
1127 struct in_ifaddr *prim = ifa;
1128 __be32 mask = ifa->ifa_mask;
1129 __be32 addr = ifa->ifa_local;
1130 __be32 prefix = ifa->ifa_address & mask;
1131
1132 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1133 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1134 if (!prim) {
1135 pr_warn("%s: bug: prim == NULL\n", __func__);
1136 return;
1137 }
1138 }
1139
1140 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1141
1142 if (!(dev->flags & IFF_UP))
1143 return;
1144
1145 /* Add broadcast address, if it is explicitly assigned. */
1146 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) {
1147 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1148 prim, 0);
1149 arp_invalidate(dev, ifa->ifa_broadcast, false);
1150 }
1151
1152 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1153 (prefix != addr || ifa->ifa_prefixlen < 32)) {
1154 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1155 fib_magic(RTM_NEWROUTE,
1156 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1157 prefix, ifa->ifa_prefixlen, prim,
1158 ifa->ifa_rt_priority);
1159
1160 /* Add the network broadcast address, when it makes sense */
1161 if (ifa->ifa_prefixlen < 31) {
1162 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1163 32, prim, 0);
1164 arp_invalidate(dev, prefix | ~mask, false);
1165 }
1166 }
1167 }
1168
fib_modify_prefix_metric(struct in_ifaddr * ifa,u32 new_metric)1169 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1170 {
1171 __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1172 struct in_device *in_dev = ifa->ifa_dev;
1173 struct net_device *dev = in_dev->dev;
1174
1175 if (!(dev->flags & IFF_UP) ||
1176 ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1177 ipv4_is_zeronet(prefix) ||
1178 (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1179 return;
1180
1181 /* add the new */
1182 fib_magic(RTM_NEWROUTE,
1183 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1184 prefix, ifa->ifa_prefixlen, ifa, new_metric);
1185
1186 /* delete the old */
1187 fib_magic(RTM_DELROUTE,
1188 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1189 prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1190 }
1191
1192 /* Delete primary or secondary address.
1193 * Optionally, on secondary address promotion consider the addresses
1194 * from subnet iprim as deleted, even if they are in device list.
1195 * In this case the secondary ifa can be in device list.
1196 */
fib_del_ifaddr(struct in_ifaddr * ifa,struct in_ifaddr * iprim)1197 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1198 {
1199 struct in_device *in_dev = ifa->ifa_dev;
1200 struct net_device *dev = in_dev->dev;
1201 struct in_ifaddr *ifa1;
1202 struct in_ifaddr *prim = ifa, *prim1 = NULL;
1203 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1204 __be32 any = ifa->ifa_address & ifa->ifa_mask;
1205 #define LOCAL_OK 1
1206 #define BRD_OK 2
1207 #define BRD0_OK 4
1208 #define BRD1_OK 8
1209 unsigned int ok = 0;
1210 int subnet = 0; /* Primary network */
1211 int gone = 1; /* Address is missing */
1212 int same_prefsrc = 0; /* Another primary with same IP */
1213
1214 if (ifa->ifa_flags & IFA_F_SECONDARY) {
1215 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1216 if (!prim) {
1217 /* if the device has been deleted, we don't perform
1218 * address promotion
1219 */
1220 if (!in_dev->dead)
1221 pr_warn("%s: bug: prim == NULL\n", __func__);
1222 return;
1223 }
1224 if (iprim && iprim != prim) {
1225 pr_warn("%s: bug: iprim != prim\n", __func__);
1226 return;
1227 }
1228 } else if (!ipv4_is_zeronet(any) &&
1229 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1230 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1231 fib_magic(RTM_DELROUTE,
1232 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1233 any, ifa->ifa_prefixlen, prim, 0);
1234 subnet = 1;
1235 }
1236
1237 if (in_dev->dead)
1238 goto no_promotions;
1239
1240 /* Deletion is more complicated than add.
1241 * We should take care of not to delete too much :-)
1242 *
1243 * Scan address list to be sure that addresses are really gone.
1244 */
1245 rcu_read_lock();
1246 in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1247 if (ifa1 == ifa) {
1248 /* promotion, keep the IP */
1249 gone = 0;
1250 continue;
1251 }
1252 /* Ignore IFAs from our subnet */
1253 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1254 inet_ifa_match(ifa1->ifa_address, iprim))
1255 continue;
1256
1257 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1258 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1259 /* Another address from our subnet? */
1260 if (ifa1->ifa_mask == prim->ifa_mask &&
1261 inet_ifa_match(ifa1->ifa_address, prim))
1262 prim1 = prim;
1263 else {
1264 /* We reached the secondaries, so
1265 * same_prefsrc should be determined.
1266 */
1267 if (!same_prefsrc)
1268 continue;
1269 /* Search new prim1 if ifa1 is not
1270 * using the current prim1
1271 */
1272 if (!prim1 ||
1273 ifa1->ifa_mask != prim1->ifa_mask ||
1274 !inet_ifa_match(ifa1->ifa_address, prim1))
1275 prim1 = inet_ifa_byprefix(in_dev,
1276 ifa1->ifa_address,
1277 ifa1->ifa_mask);
1278 if (!prim1)
1279 continue;
1280 if (prim1->ifa_local != prim->ifa_local)
1281 continue;
1282 }
1283 } else {
1284 if (prim->ifa_local != ifa1->ifa_local)
1285 continue;
1286 prim1 = ifa1;
1287 if (prim != prim1)
1288 same_prefsrc = 1;
1289 }
1290 if (ifa->ifa_local == ifa1->ifa_local)
1291 ok |= LOCAL_OK;
1292 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1293 ok |= BRD_OK;
1294 if (brd == ifa1->ifa_broadcast)
1295 ok |= BRD1_OK;
1296 if (any == ifa1->ifa_broadcast)
1297 ok |= BRD0_OK;
1298 /* primary has network specific broadcasts */
1299 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1300 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1301 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1302
1303 if (!ipv4_is_zeronet(any1)) {
1304 if (ifa->ifa_broadcast == brd1 ||
1305 ifa->ifa_broadcast == any1)
1306 ok |= BRD_OK;
1307 if (brd == brd1 || brd == any1)
1308 ok |= BRD1_OK;
1309 if (any == brd1 || any == any1)
1310 ok |= BRD0_OK;
1311 }
1312 }
1313 }
1314 rcu_read_unlock();
1315
1316 no_promotions:
1317 if (!(ok & BRD_OK))
1318 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1319 prim, 0);
1320 if (subnet && ifa->ifa_prefixlen < 31) {
1321 if (!(ok & BRD1_OK))
1322 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1323 prim, 0);
1324 if (!(ok & BRD0_OK))
1325 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1326 prim, 0);
1327 }
1328 if (!(ok & LOCAL_OK)) {
1329 unsigned int addr_type;
1330
1331 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1332
1333 /* Check, that this local address finally disappeared. */
1334 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1335 ifa->ifa_local);
1336 if (gone && addr_type != RTN_LOCAL) {
1337 /* And the last, but not the least thing.
1338 * We must flush stray FIB entries.
1339 *
1340 * First of all, we scan fib_info list searching
1341 * for stray nexthop entries, then ignite fib_flush.
1342 */
1343 if (fib_sync_down_addr(dev, ifa->ifa_local))
1344 fib_flush(dev_net(dev));
1345 }
1346 }
1347 #undef LOCAL_OK
1348 #undef BRD_OK
1349 #undef BRD0_OK
1350 #undef BRD1_OK
1351 }
1352
nl_fib_lookup(struct net * net,struct fib_result_nl * frn)1353 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1354 {
1355
1356 struct fib_result res;
1357 struct flowi4 fl4 = {
1358 .flowi4_mark = frn->fl_mark,
1359 .daddr = frn->fl_addr,
1360 .flowi4_tos = frn->fl_tos & IPTOS_RT_MASK,
1361 .flowi4_scope = frn->fl_scope,
1362 };
1363 struct fib_table *tb;
1364
1365 rcu_read_lock();
1366
1367 tb = fib_get_table(net, frn->tb_id_in);
1368
1369 frn->err = -ENOENT;
1370 if (tb) {
1371 local_bh_disable();
1372
1373 frn->tb_id = tb->tb_id;
1374 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1375
1376 if (!frn->err) {
1377 frn->prefixlen = res.prefixlen;
1378 frn->nh_sel = res.nh_sel;
1379 frn->type = res.type;
1380 frn->scope = res.scope;
1381 }
1382 local_bh_enable();
1383 }
1384
1385 rcu_read_unlock();
1386 }
1387
nl_fib_input(struct sk_buff * skb)1388 static void nl_fib_input(struct sk_buff *skb)
1389 {
1390 struct net *net;
1391 struct fib_result_nl *frn;
1392 struct nlmsghdr *nlh;
1393 u32 portid;
1394
1395 net = sock_net(skb->sk);
1396 nlh = nlmsg_hdr(skb);
1397 if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1398 skb->len < nlh->nlmsg_len ||
1399 nlmsg_len(nlh) < sizeof(*frn))
1400 return;
1401
1402 skb = netlink_skb_clone(skb, GFP_KERNEL);
1403 if (!skb)
1404 return;
1405 nlh = nlmsg_hdr(skb);
1406
1407 frn = nlmsg_data(nlh);
1408 nl_fib_lookup(net, frn);
1409
1410 portid = NETLINK_CB(skb).portid; /* netlink portid */
1411 NETLINK_CB(skb).portid = 0; /* from kernel */
1412 NETLINK_CB(skb).dst_group = 0; /* unicast */
1413 nlmsg_unicast(net->ipv4.fibnl, skb, portid);
1414 }
1415
nl_fib_lookup_init(struct net * net)1416 static int __net_init nl_fib_lookup_init(struct net *net)
1417 {
1418 struct sock *sk;
1419 struct netlink_kernel_cfg cfg = {
1420 .input = nl_fib_input,
1421 };
1422
1423 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1424 if (!sk)
1425 return -EAFNOSUPPORT;
1426 net->ipv4.fibnl = sk;
1427 return 0;
1428 }
1429
nl_fib_lookup_exit(struct net * net)1430 static void nl_fib_lookup_exit(struct net *net)
1431 {
1432 netlink_kernel_release(net->ipv4.fibnl);
1433 net->ipv4.fibnl = NULL;
1434 }
1435
fib_disable_ip(struct net_device * dev,unsigned long event,bool force)1436 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1437 bool force)
1438 {
1439 if (fib_sync_down_dev(dev, event, force))
1440 fib_flush(dev_net(dev));
1441 else
1442 rt_cache_flush(dev_net(dev));
1443 arp_ifdown(dev);
1444 }
1445
fib_inetaddr_event(struct notifier_block * this,unsigned long event,void * ptr)1446 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1447 {
1448 struct in_ifaddr *ifa = ptr;
1449 struct net_device *dev = ifa->ifa_dev->dev;
1450 struct net *net = dev_net(dev);
1451
1452 switch (event) {
1453 case NETDEV_UP:
1454 fib_add_ifaddr(ifa);
1455 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1456 fib_sync_up(dev, RTNH_F_DEAD);
1457 #endif
1458 atomic_inc(&net->ipv4.dev_addr_genid);
1459 rt_cache_flush(dev_net(dev));
1460 break;
1461 case NETDEV_DOWN:
1462 fib_del_ifaddr(ifa, NULL);
1463 atomic_inc(&net->ipv4.dev_addr_genid);
1464 if (!ifa->ifa_dev->ifa_list) {
1465 /* Last address was deleted from this interface.
1466 * Disable IP.
1467 */
1468 fib_disable_ip(dev, event, true);
1469 } else {
1470 rt_cache_flush(dev_net(dev));
1471 }
1472 break;
1473 }
1474 return NOTIFY_DONE;
1475 }
1476
fib_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1477 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1478 {
1479 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1480 struct netdev_notifier_changeupper_info *upper_info = ptr;
1481 struct netdev_notifier_info_ext *info_ext = ptr;
1482 struct in_device *in_dev;
1483 struct net *net = dev_net(dev);
1484 struct in_ifaddr *ifa;
1485 unsigned int flags;
1486
1487 if (event == NETDEV_UNREGISTER) {
1488 fib_disable_ip(dev, event, true);
1489 rt_flush_dev(dev);
1490 return NOTIFY_DONE;
1491 }
1492
1493 in_dev = __in_dev_get_rtnl(dev);
1494 if (!in_dev)
1495 return NOTIFY_DONE;
1496
1497 switch (event) {
1498 case NETDEV_UP:
1499 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1500 fib_add_ifaddr(ifa);
1501 }
1502 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1503 fib_sync_up(dev, RTNH_F_DEAD);
1504 #endif
1505 atomic_inc(&net->ipv4.dev_addr_genid);
1506 rt_cache_flush(net);
1507 break;
1508 case NETDEV_DOWN:
1509 fib_disable_ip(dev, event, false);
1510 break;
1511 case NETDEV_CHANGE:
1512 flags = dev_get_flags(dev);
1513 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1514 fib_sync_up(dev, RTNH_F_LINKDOWN);
1515 else
1516 fib_sync_down_dev(dev, event, false);
1517 rt_cache_flush(net);
1518 break;
1519 case NETDEV_CHANGEMTU:
1520 fib_sync_mtu(dev, info_ext->ext.mtu);
1521 rt_cache_flush(net);
1522 break;
1523 case NETDEV_CHANGEUPPER:
1524 upper_info = ptr;
1525 /* flush all routes if dev is linked to or unlinked from
1526 * an L3 master device (e.g., VRF)
1527 */
1528 if (upper_info->upper_dev &&
1529 netif_is_l3_master(upper_info->upper_dev))
1530 fib_disable_ip(dev, NETDEV_DOWN, true);
1531 break;
1532 }
1533 return NOTIFY_DONE;
1534 }
1535
1536 static struct notifier_block fib_inetaddr_notifier = {
1537 .notifier_call = fib_inetaddr_event,
1538 };
1539
1540 static struct notifier_block fib_netdev_notifier = {
1541 .notifier_call = fib_netdev_event,
1542 };
1543
ip_fib_net_init(struct net * net)1544 static int __net_init ip_fib_net_init(struct net *net)
1545 {
1546 int err;
1547 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1548
1549 err = fib4_notifier_init(net);
1550 if (err)
1551 return err;
1552
1553 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1554 /* Default to 3-tuple */
1555 net->ipv4.sysctl_fib_multipath_hash_fields =
1556 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
1557 #endif
1558
1559 /* Avoid false sharing : Use at least a full cache line */
1560 size = max_t(size_t, size, L1_CACHE_BYTES);
1561
1562 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1563 if (!net->ipv4.fib_table_hash) {
1564 err = -ENOMEM;
1565 goto err_table_hash_alloc;
1566 }
1567
1568 err = fib4_rules_init(net);
1569 if (err < 0)
1570 goto err_rules_init;
1571 return 0;
1572
1573 err_rules_init:
1574 kfree(net->ipv4.fib_table_hash);
1575 err_table_hash_alloc:
1576 fib4_notifier_exit(net);
1577 return err;
1578 }
1579
ip_fib_net_exit(struct net * net)1580 static void ip_fib_net_exit(struct net *net)
1581 {
1582 int i;
1583
1584 ASSERT_RTNL();
1585 #ifdef CONFIG_IP_MULTIPLE_TABLES
1586 RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1587 RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1588 #endif
1589 /* Destroy the tables in reverse order to guarantee that the
1590 * local table, ID 255, is destroyed before the main table, ID
1591 * 254. This is necessary as the local table may contain
1592 * references to data contained in the main table.
1593 */
1594 for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1595 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1596 struct hlist_node *tmp;
1597 struct fib_table *tb;
1598
1599 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1600 hlist_del(&tb->tb_hlist);
1601 fib_table_flush(net, tb, true);
1602 fib_free_table(tb);
1603 }
1604 }
1605
1606 #ifdef CONFIG_IP_MULTIPLE_TABLES
1607 fib4_rules_exit(net);
1608 #endif
1609
1610 kfree(net->ipv4.fib_table_hash);
1611 fib4_notifier_exit(net);
1612 }
1613
fib_net_init(struct net * net)1614 static int __net_init fib_net_init(struct net *net)
1615 {
1616 int error;
1617
1618 #ifdef CONFIG_IP_ROUTE_CLASSID
1619 atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
1620 #endif
1621 error = ip_fib_net_init(net);
1622 if (error < 0)
1623 goto out;
1624 error = nl_fib_lookup_init(net);
1625 if (error < 0)
1626 goto out_nlfl;
1627 error = fib_proc_init(net);
1628 if (error < 0)
1629 goto out_proc;
1630 out:
1631 return error;
1632
1633 out_proc:
1634 nl_fib_lookup_exit(net);
1635 out_nlfl:
1636 rtnl_lock();
1637 ip_fib_net_exit(net);
1638 rtnl_unlock();
1639 goto out;
1640 }
1641
fib_net_exit(struct net * net)1642 static void __net_exit fib_net_exit(struct net *net)
1643 {
1644 fib_proc_exit(net);
1645 nl_fib_lookup_exit(net);
1646 }
1647
fib_net_exit_batch(struct list_head * net_list)1648 static void __net_exit fib_net_exit_batch(struct list_head *net_list)
1649 {
1650 struct net *net;
1651
1652 rtnl_lock();
1653 list_for_each_entry(net, net_list, exit_list)
1654 ip_fib_net_exit(net);
1655
1656 rtnl_unlock();
1657 }
1658
1659 static struct pernet_operations fib_net_ops = {
1660 .init = fib_net_init,
1661 .exit = fib_net_exit,
1662 .exit_batch = fib_net_exit_batch,
1663 };
1664
ip_fib_init(void)1665 void __init ip_fib_init(void)
1666 {
1667 fib_trie_init();
1668
1669 register_pernet_subsys(&fib_net_ops);
1670
1671 register_netdevice_notifier(&fib_netdev_notifier);
1672 register_inetaddr_notifier(&fib_inetaddr_notifier);
1673
1674 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1675 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1676 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1677 }
1678