2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * IPv4 Forwarding Information Base: semantics.
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
16 #include <asm/uaccess.h>
17 #include <asm/system.h>
18 #include <linux/bitops.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/jiffies.h>
23 #include <linux/string.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/errno.h>
28 #include <linux/inet.h>
29 #include <linux/inetdevice.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/proc_fs.h>
33 #include <linux/skbuff.h>
34 #include <linux/init.h>
35 #include <linux/slab.h>
39 #include <net/protocol.h>
40 #include <net/route.h>
43 #include <net/ip_fib.h>
44 #include <net/netlink.h>
45 #include <net/nexthop.h>
47 #include "fib_lookup.h"
49 static DEFINE_SPINLOCK(fib_info_lock);
50 static struct hlist_head *fib_info_hash;
51 static struct hlist_head *fib_info_laddrhash;
52 static unsigned int fib_info_hash_size;
53 static unsigned int fib_info_cnt;
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
61 static DEFINE_SPINLOCK(fib_multipath_lock);
63 #define for_nexthops(fi) { \
64 int nhsel; const struct fib_nh *nh; \
65 for (nhsel = 0, nh = (fi)->fib_nh; \
66 nhsel < (fi)->fib_nhs; \
69 #define change_nexthops(fi) { \
70 int nhsel; struct fib_nh *nexthop_nh; \
71 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
72 nhsel < (fi)->fib_nhs; \
73 nexthop_nh++, nhsel++)
75 #else /* CONFIG_IP_ROUTE_MULTIPATH */
77 /* Hope, that gcc will optimize it to get rid of dummy loop */
79 #define for_nexthops(fi) { \
80 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
81 for (nhsel = 0; nhsel < 1; nhsel++)
83 #define change_nexthops(fi) { \
85 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
86 for (nhsel = 0; nhsel < 1; nhsel++)
88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
90 #define endfor_nexthops(fi) }
93 const struct fib_prop fib_props[RTN_MAX + 1] = {
96 .scope = RT_SCOPE_NOWHERE,
100 .scope = RT_SCOPE_UNIVERSE,
104 .scope = RT_SCOPE_HOST,
108 .scope = RT_SCOPE_LINK,
112 .scope = RT_SCOPE_LINK,
116 .scope = RT_SCOPE_UNIVERSE,
120 .scope = RT_SCOPE_UNIVERSE,
122 [RTN_UNREACHABLE] = {
123 .error = -EHOSTUNREACH,
124 .scope = RT_SCOPE_UNIVERSE,
128 .scope = RT_SCOPE_UNIVERSE,
132 .scope = RT_SCOPE_UNIVERSE,
136 .scope = RT_SCOPE_NOWHERE,
140 .scope = RT_SCOPE_NOWHERE,
145 /* Release a nexthop info record */
147 static void free_fib_info_rcu(struct rcu_head *head)
149 struct fib_info *fi = container_of(head, struct fib_info, rcu);
151 if (fi->fib_metrics != (u32 *) dst_default_metrics)
152 kfree(fi->fib_metrics);
156 void free_fib_info(struct fib_info *fi)
158 if (fi->fib_dead == 0) {
159 pr_warning("Freeing alive fib_info %p\n", fi);
162 change_nexthops(fi) {
163 if (nexthop_nh->nh_dev)
164 dev_put(nexthop_nh->nh_dev);
165 nexthop_nh->nh_dev = NULL;
166 } endfor_nexthops(fi);
168 release_net(fi->fib_net);
169 call_rcu(&fi->rcu, free_fib_info_rcu);
172 void fib_release_info(struct fib_info *fi)
174 spin_lock_bh(&fib_info_lock);
175 if (fi && --fi->fib_treeref == 0) {
176 hlist_del(&fi->fib_hash);
178 hlist_del(&fi->fib_lhash);
179 change_nexthops(fi) {
180 if (!nexthop_nh->nh_dev)
182 hlist_del(&nexthop_nh->nh_hash);
183 } endfor_nexthops(fi)
187 spin_unlock_bh(&fib_info_lock);
190 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
192 const struct fib_nh *onh = ofi->fib_nh;
195 if (nh->nh_oif != onh->nh_oif ||
196 nh->nh_gw != onh->nh_gw ||
197 nh->nh_scope != onh->nh_scope ||
198 #ifdef CONFIG_IP_ROUTE_MULTIPATH
199 nh->nh_weight != onh->nh_weight ||
201 #ifdef CONFIG_IP_ROUTE_CLASSID
202 nh->nh_tclassid != onh->nh_tclassid ||
204 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
207 } endfor_nexthops(fi);
211 static inline unsigned int fib_devindex_hashfn(unsigned int val)
213 unsigned int mask = DEVINDEX_HASHSIZE - 1;
216 (val >> DEVINDEX_HASHBITS) ^
217 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
220 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
222 unsigned int mask = (fib_info_hash_size - 1);
223 unsigned int val = fi->fib_nhs;
225 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
226 val ^= (__force u32)fi->fib_prefsrc;
227 val ^= fi->fib_priority;
229 val ^= fib_devindex_hashfn(nh->nh_oif);
230 } endfor_nexthops(fi)
232 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
235 static struct fib_info *fib_find_info(const struct fib_info *nfi)
237 struct hlist_head *head;
238 struct hlist_node *node;
242 hash = fib_info_hashfn(nfi);
243 head = &fib_info_hash[hash];
245 hlist_for_each_entry(fi, node, head, fib_hash) {
246 if (!net_eq(fi->fib_net, nfi->fib_net))
248 if (fi->fib_nhs != nfi->fib_nhs)
250 if (nfi->fib_protocol == fi->fib_protocol &&
251 nfi->fib_scope == fi->fib_scope &&
252 nfi->fib_prefsrc == fi->fib_prefsrc &&
253 nfi->fib_priority == fi->fib_priority &&
254 memcmp(nfi->fib_metrics, fi->fib_metrics,
255 sizeof(u32) * RTAX_MAX) == 0 &&
256 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
257 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
264 /* Check, that the gateway is already configured.
265 * Used only by redirect accept routine.
267 int ip_fib_check_default(__be32 gw, struct net_device *dev)
269 struct hlist_head *head;
270 struct hlist_node *node;
274 spin_lock(&fib_info_lock);
276 hash = fib_devindex_hashfn(dev->ifindex);
277 head = &fib_info_devhash[hash];
278 hlist_for_each_entry(nh, node, head, nh_hash) {
279 if (nh->nh_dev == dev &&
281 !(nh->nh_flags & RTNH_F_DEAD)) {
282 spin_unlock(&fib_info_lock);
287 spin_unlock(&fib_info_lock);
292 static inline size_t fib_nlmsg_size(struct fib_info *fi)
294 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
295 + nla_total_size(4) /* RTA_TABLE */
296 + nla_total_size(4) /* RTA_DST */
297 + nla_total_size(4) /* RTA_PRIORITY */
298 + nla_total_size(4); /* RTA_PREFSRC */
300 /* space for nested metrics */
301 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
304 /* Also handles the special case fib_nhs == 1 */
306 /* each nexthop is packed in an attribute */
307 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
309 /* may contain flow and gateway attribute */
310 nhsize += 2 * nla_total_size(4);
312 /* all nexthops are packed in a nested attribute */
313 payload += nla_total_size(fi->fib_nhs * nhsize);
319 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
320 int dst_len, u32 tb_id, struct nl_info *info,
321 unsigned int nlm_flags)
324 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
327 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
331 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
332 fa->fa_type, key, dst_len,
333 fa->fa_tos, fa->fa_info, nlm_flags);
335 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
336 WARN_ON(err == -EMSGSIZE);
340 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
341 info->nlh, GFP_KERNEL);
345 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
348 /* Return the first fib alias matching TOS with
349 * priority less than or equal to PRIO.
351 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
354 struct fib_alias *fa;
355 list_for_each_entry(fa, fah, fa_list) {
356 if (fa->fa_tos > tos)
358 if (fa->fa_info->fib_priority >= prio ||
366 int fib_detect_death(struct fib_info *fi, int order,
367 struct fib_info **last_resort, int *last_idx, int dflt)
370 int state = NUD_NONE;
372 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
374 state = n->nud_state;
377 if (state == NUD_REACHABLE)
379 if ((state & NUD_VALID) && order != dflt)
381 if ((state & NUD_VALID) ||
382 (*last_idx < 0 && order > dflt)) {
389 #ifdef CONFIG_IP_ROUTE_MULTIPATH
391 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
395 while (rtnh_ok(rtnh, remaining)) {
397 rtnh = rtnh_next(rtnh, &remaining);
400 /* leftover implies invalid nexthop configuration, discard it */
401 return remaining > 0 ? 0 : nhs;
404 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
405 int remaining, struct fib_config *cfg)
407 change_nexthops(fi) {
410 if (!rtnh_ok(rtnh, remaining))
413 nexthop_nh->nh_flags =
414 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
415 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
416 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
418 attrlen = rtnh_attrlen(rtnh);
420 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
422 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
423 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
424 #ifdef CONFIG_IP_ROUTE_CLASSID
425 nla = nla_find(attrs, attrlen, RTA_FLOW);
426 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
430 rtnh = rtnh_next(rtnh, &remaining);
431 } endfor_nexthops(fi);
438 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
440 #ifdef CONFIG_IP_ROUTE_MULTIPATH
441 struct rtnexthop *rtnh;
445 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
448 if (cfg->fc_oif || cfg->fc_gw) {
449 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
450 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
455 #ifdef CONFIG_IP_ROUTE_MULTIPATH
456 if (cfg->fc_mp == NULL)
460 remaining = cfg->fc_mp_len;
465 if (!rtnh_ok(rtnh, remaining))
468 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
471 attrlen = rtnh_attrlen(rtnh);
473 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
475 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
476 if (nla && nla_get_be32(nla) != nh->nh_gw)
478 #ifdef CONFIG_IP_ROUTE_CLASSID
479 nla = nla_find(attrs, attrlen, RTA_FLOW);
480 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
485 rtnh = rtnh_next(rtnh, &remaining);
486 } endfor_nexthops(fi);
496 * Semantics of nexthop is very messy by historical reasons.
497 * We have to take into account, that:
498 * a) gateway can be actually local interface address,
499 * so that gatewayed route is direct.
500 * b) gateway must be on-link address, possibly
501 * described not by an ifaddr, but also by a direct route.
502 * c) If both gateway and interface are specified, they should not
504 * d) If we use tunnel routes, gateway could be not on-link.
506 * Attempt to reconcile all of these (alas, self-contradictory) conditions
507 * results in pretty ugly and hairy code with obscure logic.
509 * I chose to generalized it instead, so that the size
510 * of code does not increase practically, but it becomes
512 * Every prefix is assigned a "scope" value: "host" is local address,
513 * "link" is direct route,
514 * [ ... "site" ... "interior" ... ]
515 * and "universe" is true gateway route with global meaning.
517 * Every prefix refers to a set of "nexthop"s (gw, oif),
518 * where gw must have narrower scope. This recursion stops
519 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
520 * which means that gw is forced to be on link.
522 * Code is still hairy, but now it is apparently logically
523 * consistent and very flexible. F.e. as by-product it allows
524 * to co-exists in peace independent exterior and interior
527 * Normally it looks as following.
529 * {universe prefix} -> (gw, oif) [scope link]
531 * |-> {link prefix} -> (gw, oif) [scope local]
533 * |-> {local prefix} (terminal node)
535 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
540 struct net_device *dev;
542 net = cfg->fc_nlinfo.nl_net;
544 struct fib_result res;
546 if (nh->nh_flags & RTNH_F_ONLINK) {
548 if (cfg->fc_scope >= RT_SCOPE_LINK)
550 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
552 dev = __dev_get_by_index(net, nh->nh_oif);
555 if (!(dev->flags & IFF_UP))
559 nh->nh_scope = RT_SCOPE_LINK;
564 struct flowi4 fl4 = {
566 .flowi4_scope = cfg->fc_scope + 1,
567 .flowi4_oif = nh->nh_oif,
570 /* It is not necessary, but requires a bit of thinking */
571 if (fl4.flowi4_scope < RT_SCOPE_LINK)
572 fl4.flowi4_scope = RT_SCOPE_LINK;
573 err = fib_lookup(net, &fl4, &res);
580 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
582 nh->nh_scope = res.scope;
583 nh->nh_oif = FIB_RES_OIF(res);
584 nh->nh_dev = dev = FIB_RES_DEV(res);
588 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
590 struct in_device *in_dev;
592 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
597 in_dev = inetdev_by_index(net, nh->nh_oif);
601 if (!(in_dev->dev->flags & IFF_UP))
603 nh->nh_dev = in_dev->dev;
604 dev_hold(nh->nh_dev);
605 nh->nh_scope = RT_SCOPE_HOST;
613 static inline unsigned int fib_laddr_hashfn(__be32 val)
615 unsigned int mask = (fib_info_hash_size - 1);
617 return ((__force u32)val ^
618 ((__force u32)val >> 7) ^
619 ((__force u32)val >> 14)) & mask;
622 static struct hlist_head *fib_info_hash_alloc(int bytes)
624 if (bytes <= PAGE_SIZE)
625 return kzalloc(bytes, GFP_KERNEL);
627 return (struct hlist_head *)
628 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
632 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
637 if (bytes <= PAGE_SIZE)
640 free_pages((unsigned long) hash, get_order(bytes));
643 static void fib_info_hash_move(struct hlist_head *new_info_hash,
644 struct hlist_head *new_laddrhash,
645 unsigned int new_size)
647 struct hlist_head *old_info_hash, *old_laddrhash;
648 unsigned int old_size = fib_info_hash_size;
649 unsigned int i, bytes;
651 spin_lock_bh(&fib_info_lock);
652 old_info_hash = fib_info_hash;
653 old_laddrhash = fib_info_laddrhash;
654 fib_info_hash_size = new_size;
656 for (i = 0; i < old_size; i++) {
657 struct hlist_head *head = &fib_info_hash[i];
658 struct hlist_node *node, *n;
661 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
662 struct hlist_head *dest;
663 unsigned int new_hash;
665 hlist_del(&fi->fib_hash);
667 new_hash = fib_info_hashfn(fi);
668 dest = &new_info_hash[new_hash];
669 hlist_add_head(&fi->fib_hash, dest);
672 fib_info_hash = new_info_hash;
674 for (i = 0; i < old_size; i++) {
675 struct hlist_head *lhead = &fib_info_laddrhash[i];
676 struct hlist_node *node, *n;
679 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
680 struct hlist_head *ldest;
681 unsigned int new_hash;
683 hlist_del(&fi->fib_lhash);
685 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
686 ldest = &new_laddrhash[new_hash];
687 hlist_add_head(&fi->fib_lhash, ldest);
690 fib_info_laddrhash = new_laddrhash;
692 spin_unlock_bh(&fib_info_lock);
694 bytes = old_size * sizeof(struct hlist_head *);
695 fib_info_hash_free(old_info_hash, bytes);
696 fib_info_hash_free(old_laddrhash, bytes);
699 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
701 nh->nh_saddr = inet_select_addr(nh->nh_dev,
703 nh->nh_parent->fib_scope);
704 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
709 struct fib_info *fib_create_info(struct fib_config *cfg)
712 struct fib_info *fi = NULL;
713 struct fib_info *ofi;
715 struct net *net = cfg->fc_nlinfo.nl_net;
717 if (cfg->fc_type > RTN_MAX)
720 /* Fast check to catch the most weird cases */
721 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
724 #ifdef CONFIG_IP_ROUTE_MULTIPATH
726 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
733 if (fib_info_cnt >= fib_info_hash_size) {
734 unsigned int new_size = fib_info_hash_size << 1;
735 struct hlist_head *new_info_hash;
736 struct hlist_head *new_laddrhash;
741 bytes = new_size * sizeof(struct hlist_head *);
742 new_info_hash = fib_info_hash_alloc(bytes);
743 new_laddrhash = fib_info_hash_alloc(bytes);
744 if (!new_info_hash || !new_laddrhash) {
745 fib_info_hash_free(new_info_hash, bytes);
746 fib_info_hash_free(new_laddrhash, bytes);
748 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
750 if (!fib_info_hash_size)
754 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
758 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
759 if (!fi->fib_metrics)
762 fi->fib_metrics = (u32 *) dst_default_metrics;
765 fi->fib_net = hold_net(net);
766 fi->fib_protocol = cfg->fc_protocol;
767 fi->fib_scope = cfg->fc_scope;
768 fi->fib_flags = cfg->fc_flags;
769 fi->fib_priority = cfg->fc_priority;
770 fi->fib_prefsrc = cfg->fc_prefsrc;
773 change_nexthops(fi) {
774 nexthop_nh->nh_parent = fi;
775 } endfor_nexthops(fi)
781 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
782 int type = nla_type(nla);
787 fi->fib_metrics[type - 1] = nla_get_u32(nla);
793 #ifdef CONFIG_IP_ROUTE_MULTIPATH
794 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
797 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
799 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
801 #ifdef CONFIG_IP_ROUTE_CLASSID
802 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
809 struct fib_nh *nh = fi->fib_nh;
811 nh->nh_oif = cfg->fc_oif;
812 nh->nh_gw = cfg->fc_gw;
813 nh->nh_flags = cfg->fc_flags;
814 #ifdef CONFIG_IP_ROUTE_CLASSID
815 nh->nh_tclassid = cfg->fc_flow;
817 #ifdef CONFIG_IP_ROUTE_MULTIPATH
822 if (fib_props[cfg->fc_type].error) {
823 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
827 switch (cfg->fc_type) {
839 if (cfg->fc_scope > RT_SCOPE_HOST)
842 if (cfg->fc_scope == RT_SCOPE_HOST) {
843 struct fib_nh *nh = fi->fib_nh;
845 /* Local address is added. */
846 if (nhs != 1 || nh->nh_gw)
848 nh->nh_scope = RT_SCOPE_NOWHERE;
849 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
851 if (nh->nh_dev == NULL)
854 change_nexthops(fi) {
855 err = fib_check_nh(cfg, fi, nexthop_nh);
858 } endfor_nexthops(fi)
861 if (fi->fib_prefsrc) {
862 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
863 fi->fib_prefsrc != cfg->fc_dst)
864 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
868 change_nexthops(fi) {
869 fib_info_update_nh_saddr(net, nexthop_nh);
870 } endfor_nexthops(fi)
873 ofi = fib_find_info(fi);
882 atomic_inc(&fi->fib_clntref);
883 spin_lock_bh(&fib_info_lock);
884 hlist_add_head(&fi->fib_hash,
885 &fib_info_hash[fib_info_hashfn(fi)]);
886 if (fi->fib_prefsrc) {
887 struct hlist_head *head;
889 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
890 hlist_add_head(&fi->fib_lhash, head);
892 change_nexthops(fi) {
893 struct hlist_head *head;
896 if (!nexthop_nh->nh_dev)
898 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
899 head = &fib_info_devhash[hash];
900 hlist_add_head(&nexthop_nh->nh_hash, head);
901 } endfor_nexthops(fi)
902 spin_unlock_bh(&fib_info_lock);
917 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
918 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
919 struct fib_info *fi, unsigned int flags)
921 struct nlmsghdr *nlh;
924 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
928 rtm = nlmsg_data(nlh);
929 rtm->rtm_family = AF_INET;
930 rtm->rtm_dst_len = dst_len;
931 rtm->rtm_src_len = 0;
934 rtm->rtm_table = tb_id;
936 rtm->rtm_table = RT_TABLE_COMPAT;
937 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
938 rtm->rtm_type = type;
939 rtm->rtm_flags = fi->fib_flags;
940 rtm->rtm_scope = fi->fib_scope;
941 rtm->rtm_protocol = fi->fib_protocol;
943 if (rtm->rtm_dst_len)
944 NLA_PUT_BE32(skb, RTA_DST, dst);
946 if (fi->fib_priority)
947 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
949 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
950 goto nla_put_failure;
953 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
955 if (fi->fib_nhs == 1) {
956 if (fi->fib_nh->nh_gw)
957 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
959 if (fi->fib_nh->nh_oif)
960 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
961 #ifdef CONFIG_IP_ROUTE_CLASSID
962 if (fi->fib_nh[0].nh_tclassid)
963 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
966 #ifdef CONFIG_IP_ROUTE_MULTIPATH
967 if (fi->fib_nhs > 1) {
968 struct rtnexthop *rtnh;
971 mp = nla_nest_start(skb, RTA_MULTIPATH);
973 goto nla_put_failure;
976 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
978 goto nla_put_failure;
980 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
981 rtnh->rtnh_hops = nh->nh_weight - 1;
982 rtnh->rtnh_ifindex = nh->nh_oif;
985 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
986 #ifdef CONFIG_IP_ROUTE_CLASSID
988 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
990 /* length of rtnetlink header + attributes */
991 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
992 } endfor_nexthops(fi);
994 nla_nest_end(skb, mp);
997 return nlmsg_end(skb, nlh);
1000 nlmsg_cancel(skb, nlh);
1006 * - local address disappeared -> we must delete all the entries
1008 * - device went down -> we must shutdown all nexthops going via it.
1010 int fib_sync_down_addr(struct net *net, __be32 local)
1013 unsigned int hash = fib_laddr_hashfn(local);
1014 struct hlist_head *head = &fib_info_laddrhash[hash];
1015 struct hlist_node *node;
1016 struct fib_info *fi;
1018 if (fib_info_laddrhash == NULL || local == 0)
1021 hlist_for_each_entry(fi, node, head, fib_lhash) {
1022 if (!net_eq(fi->fib_net, net))
1024 if (fi->fib_prefsrc == local) {
1025 fi->fib_flags |= RTNH_F_DEAD;
1032 int fib_sync_down_dev(struct net_device *dev, int force)
1035 int scope = RT_SCOPE_NOWHERE;
1036 struct fib_info *prev_fi = NULL;
1037 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1038 struct hlist_head *head = &fib_info_devhash[hash];
1039 struct hlist_node *node;
1045 hlist_for_each_entry(nh, node, head, nh_hash) {
1046 struct fib_info *fi = nh->nh_parent;
1049 BUG_ON(!fi->fib_nhs);
1050 if (nh->nh_dev != dev || fi == prev_fi)
1054 change_nexthops(fi) {
1055 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1057 else if (nexthop_nh->nh_dev == dev &&
1058 nexthop_nh->nh_scope != scope) {
1059 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1060 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1061 spin_lock_bh(&fib_multipath_lock);
1062 fi->fib_power -= nexthop_nh->nh_power;
1063 nexthop_nh->nh_power = 0;
1064 spin_unlock_bh(&fib_multipath_lock);
1068 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1069 if (force > 1 && nexthop_nh->nh_dev == dev) {
1074 } endfor_nexthops(fi)
1075 if (dead == fi->fib_nhs) {
1076 fi->fib_flags |= RTNH_F_DEAD;
1084 /* Must be invoked inside of an RCU protected region. */
1085 void fib_select_default(struct fib_result *res)
1087 struct fib_info *fi = NULL, *last_resort = NULL;
1088 struct list_head *fa_head = res->fa_head;
1089 struct fib_table *tb = res->table;
1090 int order = -1, last_idx = -1;
1091 struct fib_alias *fa;
1093 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1094 struct fib_info *next_fi = fa->fa_info;
1096 if (next_fi->fib_scope != res->scope ||
1097 fa->fa_type != RTN_UNICAST)
1100 if (next_fi->fib_priority > res->fi->fib_priority)
1102 if (!next_fi->fib_nh[0].nh_gw ||
1103 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1106 fib_alias_accessed(fa);
1109 if (next_fi != res->fi)
1111 } else if (!fib_detect_death(fi, order, &last_resort,
1112 &last_idx, tb->tb_default)) {
1113 fib_result_assign(res, fi);
1114 tb->tb_default = order;
1121 if (order <= 0 || fi == NULL) {
1122 tb->tb_default = -1;
1126 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1128 fib_result_assign(res, fi);
1129 tb->tb_default = order;
1134 fib_result_assign(res, last_resort);
1135 tb->tb_default = last_idx;
1140 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1143 * Dead device goes up. We wake up dead nexthops.
1144 * It takes sense only on multipath routes.
1146 int fib_sync_up(struct net_device *dev)
1148 struct fib_info *prev_fi;
1150 struct hlist_head *head;
1151 struct hlist_node *node;
1155 if (!(dev->flags & IFF_UP))
1159 hash = fib_devindex_hashfn(dev->ifindex);
1160 head = &fib_info_devhash[hash];
1163 hlist_for_each_entry(nh, node, head, nh_hash) {
1164 struct fib_info *fi = nh->nh_parent;
1167 BUG_ON(!fi->fib_nhs);
1168 if (nh->nh_dev != dev || fi == prev_fi)
1173 change_nexthops(fi) {
1174 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1178 if (nexthop_nh->nh_dev == NULL ||
1179 !(nexthop_nh->nh_dev->flags & IFF_UP))
1181 if (nexthop_nh->nh_dev != dev ||
1182 !__in_dev_get_rtnl(dev))
1185 spin_lock_bh(&fib_multipath_lock);
1186 nexthop_nh->nh_power = 0;
1187 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1188 spin_unlock_bh(&fib_multipath_lock);
1189 } endfor_nexthops(fi)
1192 fi->fib_flags &= ~RTNH_F_DEAD;
1201 * The algorithm is suboptimal, but it provides really
1202 * fair weighted route distribution.
1204 void fib_select_multipath(struct fib_result *res)
1206 struct fib_info *fi = res->fi;
1209 spin_lock_bh(&fib_multipath_lock);
1210 if (fi->fib_power <= 0) {
1212 change_nexthops(fi) {
1213 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1214 power += nexthop_nh->nh_weight;
1215 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1217 } endfor_nexthops(fi);
1218 fi->fib_power = power;
1220 spin_unlock_bh(&fib_multipath_lock);
1221 /* Race condition: route has just become dead. */
1228 /* w should be random number [0..fi->fib_power-1],
1229 * it is pretty bad approximation.
1232 w = jiffies % fi->fib_power;
1234 change_nexthops(fi) {
1235 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1236 nexthop_nh->nh_power) {
1237 w -= nexthop_nh->nh_power;
1239 nexthop_nh->nh_power--;
1241 res->nh_sel = nhsel;
1242 spin_unlock_bh(&fib_multipath_lock);
1246 } endfor_nexthops(fi);
1248 /* Race condition: route has just become dead. */
1250 spin_unlock_bh(&fib_multipath_lock);