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Linux/net/ipv4/fib_frontend.c

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

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