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 <linux/uaccess.h>
17 #include <linux/bitops.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/jiffies.h>
22 #include <linux/string.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/errno.h>
27 #include <linux/inet.h>
28 #include <linux/inetdevice.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/proc_fs.h>
32 #include <linux/skbuff.h>
33 #include <linux/init.h>
34 #include <linux/slab.h>
35 #include <linux/netlink.h>
39 #include <net/protocol.h>
40 #include <net/route.h>
43 #include <net/ip_fib.h>
44 #include <net/ip6_fib.h>
45 #include <net/netlink.h>
47 #include <net/lwtunnel.h>
48 #include <net/fib_notifier.h>
49 #include <net/addrconf.h>
51 #include "fib_lookup.h"
53 static DEFINE_SPINLOCK(fib_info_lock);
54 static struct hlist_head *fib_info_hash;
55 static struct hlist_head *fib_info_laddrhash;
56 static unsigned int fib_info_hash_size;
57 static unsigned int fib_info_cnt;
59 #define DEVINDEX_HASHBITS 8
60 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
61 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
63 #ifdef CONFIG_IP_ROUTE_MULTIPATH
65 #define for_nexthops(fi) { \
66 int nhsel; const struct fib_nh *nh; \
67 for (nhsel = 0, nh = (fi)->fib_nh; \
68 nhsel < (fi)->fib_nhs; \
71 #define change_nexthops(fi) { \
72 int nhsel; struct fib_nh *nexthop_nh; \
73 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
74 nhsel < (fi)->fib_nhs; \
75 nexthop_nh++, nhsel++)
77 #else /* CONFIG_IP_ROUTE_MULTIPATH */
79 /* Hope, that gcc will optimize it to get rid of dummy loop */
81 #define for_nexthops(fi) { \
82 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
83 for (nhsel = 0; nhsel < 1; nhsel++)
85 #define change_nexthops(fi) { \
87 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
88 for (nhsel = 0; nhsel < 1; nhsel++)
90 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
92 #define endfor_nexthops(fi) }
95 const struct fib_prop fib_props[RTN_MAX + 1] = {
98 .scope = RT_SCOPE_NOWHERE,
102 .scope = RT_SCOPE_UNIVERSE,
106 .scope = RT_SCOPE_HOST,
110 .scope = RT_SCOPE_LINK,
114 .scope = RT_SCOPE_LINK,
118 .scope = RT_SCOPE_UNIVERSE,
122 .scope = RT_SCOPE_UNIVERSE,
124 [RTN_UNREACHABLE] = {
125 .error = -EHOSTUNREACH,
126 .scope = RT_SCOPE_UNIVERSE,
130 .scope = RT_SCOPE_UNIVERSE,
134 .scope = RT_SCOPE_UNIVERSE,
138 .scope = RT_SCOPE_NOWHERE,
142 .scope = RT_SCOPE_NOWHERE,
146 static void rt_fibinfo_free(struct rtable __rcu **rtp)
148 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
153 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
154 * because we waited an RCU grace period before calling
155 * free_fib_info_rcu()
158 dst_dev_put(&rt->dst);
159 dst_release_immediate(&rt->dst);
162 static void free_nh_exceptions(struct fib_nh_common *nhc)
164 struct fnhe_hash_bucket *hash;
167 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
170 for (i = 0; i < FNHE_HASH_SIZE; i++) {
171 struct fib_nh_exception *fnhe;
173 fnhe = rcu_dereference_protected(hash[i].chain, 1);
175 struct fib_nh_exception *next;
177 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
179 rt_fibinfo_free(&fnhe->fnhe_rth_input);
180 rt_fibinfo_free(&fnhe->fnhe_rth_output);
190 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
197 for_each_possible_cpu(cpu) {
200 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
202 dst_dev_put(&rt->dst);
203 dst_release_immediate(&rt->dst);
209 void fib_nh_common_release(struct fib_nh_common *nhc)
212 dev_put(nhc->nhc_dev);
214 lwtstate_put(nhc->nhc_lwtstate);
215 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
216 rt_fibinfo_free(&nhc->nhc_rth_input);
217 free_nh_exceptions(nhc);
219 EXPORT_SYMBOL_GPL(fib_nh_common_release);
221 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
223 #ifdef CONFIG_IP_ROUTE_CLASSID
224 if (fib_nh->nh_tclassid)
225 net->ipv4.fib_num_tclassid_users--;
227 fib_nh_common_release(&fib_nh->nh_common);
230 /* Release a nexthop info record */
231 static void free_fib_info_rcu(struct rcu_head *head)
233 struct fib_info *fi = container_of(head, struct fib_info, rcu);
235 change_nexthops(fi) {
236 fib_nh_release(fi->fib_net, nexthop_nh);
237 } endfor_nexthops(fi);
239 ip_fib_metrics_put(fi->fib_metrics);
244 void free_fib_info(struct fib_info *fi)
246 if (fi->fib_dead == 0) {
247 pr_warn("Freeing alive fib_info %p\n", fi);
252 call_rcu(&fi->rcu, free_fib_info_rcu);
254 EXPORT_SYMBOL_GPL(free_fib_info);
256 void fib_release_info(struct fib_info *fi)
258 spin_lock_bh(&fib_info_lock);
259 if (fi && --fi->fib_treeref == 0) {
260 hlist_del(&fi->fib_hash);
262 hlist_del(&fi->fib_lhash);
263 change_nexthops(fi) {
264 if (!nexthop_nh->fib_nh_dev)
266 hlist_del(&nexthop_nh->nh_hash);
267 } endfor_nexthops(fi)
271 spin_unlock_bh(&fib_info_lock);
274 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
276 const struct fib_nh *onh = ofi->fib_nh;
279 if (nh->fib_nh_oif != onh->fib_nh_oif ||
280 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
281 nh->fib_nh_scope != onh->fib_nh_scope ||
282 #ifdef CONFIG_IP_ROUTE_MULTIPATH
283 nh->fib_nh_weight != onh->fib_nh_weight ||
285 #ifdef CONFIG_IP_ROUTE_CLASSID
286 nh->nh_tclassid != onh->nh_tclassid ||
288 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
289 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
292 if (nh->fib_nh_gw_family == AF_INET &&
293 nh->fib_nh_gw4 != onh->fib_nh_gw4)
296 if (nh->fib_nh_gw_family == AF_INET6 &&
297 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
301 } endfor_nexthops(fi);
305 static inline unsigned int fib_devindex_hashfn(unsigned int val)
307 unsigned int mask = DEVINDEX_HASHSIZE - 1;
310 (val >> DEVINDEX_HASHBITS) ^
311 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
314 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
316 unsigned int mask = (fib_info_hash_size - 1);
317 unsigned int val = fi->fib_nhs;
319 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
320 val ^= (__force u32)fi->fib_prefsrc;
321 val ^= fi->fib_priority;
323 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
324 } endfor_nexthops(fi)
326 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
329 static struct fib_info *fib_find_info(const struct fib_info *nfi)
331 struct hlist_head *head;
335 hash = fib_info_hashfn(nfi);
336 head = &fib_info_hash[hash];
338 hlist_for_each_entry(fi, head, fib_hash) {
339 if (!net_eq(fi->fib_net, nfi->fib_net))
341 if (fi->fib_nhs != nfi->fib_nhs)
343 if (nfi->fib_protocol == fi->fib_protocol &&
344 nfi->fib_scope == fi->fib_scope &&
345 nfi->fib_prefsrc == fi->fib_prefsrc &&
346 nfi->fib_priority == fi->fib_priority &&
347 nfi->fib_type == fi->fib_type &&
348 memcmp(nfi->fib_metrics, fi->fib_metrics,
349 sizeof(u32) * RTAX_MAX) == 0 &&
350 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
351 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
358 /* Check, that the gateway is already configured.
359 * Used only by redirect accept routine.
361 int ip_fib_check_default(__be32 gw, struct net_device *dev)
363 struct hlist_head *head;
367 spin_lock(&fib_info_lock);
369 hash = fib_devindex_hashfn(dev->ifindex);
370 head = &fib_info_devhash[hash];
371 hlist_for_each_entry(nh, head, nh_hash) {
372 if (nh->fib_nh_dev == dev &&
373 nh->fib_nh_gw4 == gw &&
374 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
375 spin_unlock(&fib_info_lock);
380 spin_unlock(&fib_info_lock);
385 static inline size_t fib_nlmsg_size(struct fib_info *fi)
387 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
388 + nla_total_size(4) /* RTA_TABLE */
389 + nla_total_size(4) /* RTA_DST */
390 + nla_total_size(4) /* RTA_PRIORITY */
391 + nla_total_size(4) /* RTA_PREFSRC */
392 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
394 /* space for nested metrics */
395 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
398 size_t nh_encapsize = 0;
399 /* Also handles the special case fib_nhs == 1 */
401 /* each nexthop is packed in an attribute */
402 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
404 /* may contain flow and gateway attribute */
405 nhsize += 2 * nla_total_size(4);
407 /* grab encap info */
409 if (nh->fib_nh_lws) {
411 nh_encapsize += lwtunnel_get_encap_size(
414 nh_encapsize += nla_total_size(2);
416 } endfor_nexthops(fi);
418 /* all nexthops are packed in a nested attribute */
419 payload += nla_total_size((fi->fib_nhs * nhsize) +
427 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
428 int dst_len, u32 tb_id, const struct nl_info *info,
429 unsigned int nlm_flags)
432 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
435 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
439 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
440 fa->fa_type, key, dst_len,
441 fa->fa_tos, fa->fa_info, nlm_flags);
443 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
444 WARN_ON(err == -EMSGSIZE);
448 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
449 info->nlh, GFP_KERNEL);
453 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
456 static int fib_detect_death(struct fib_info *fi, int order,
457 struct fib_info **last_resort, int *last_idx,
460 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
462 int state = NUD_NONE;
464 if (likely(nhc->nhc_gw_family == AF_INET))
465 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
466 else if (nhc->nhc_gw_family == AF_INET6)
467 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
473 state = n->nud_state;
478 if (state == NUD_REACHABLE)
480 if ((state & NUD_VALID) && order != dflt)
482 if ((state & NUD_VALID) ||
483 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
490 int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *encap,
491 u16 encap_type, void *cfg, gfp_t gfp_flags,
492 struct netlink_ext_ack *extack)
496 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
498 if (!nhc->nhc_pcpu_rth_output)
502 struct lwtunnel_state *lwtstate;
504 if (encap_type == LWTUNNEL_ENCAP_NONE) {
505 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
509 err = lwtunnel_build_state(encap_type, encap, nhc->nhc_family,
510 cfg, &lwtstate, extack);
514 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
520 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
521 nhc->nhc_pcpu_rth_output = NULL;
524 EXPORT_SYMBOL_GPL(fib_nh_common_init);
526 int fib_nh_init(struct net *net, struct fib_nh *nh,
527 struct fib_config *cfg, int nh_weight,
528 struct netlink_ext_ack *extack)
532 nh->fib_nh_family = AF_INET;
534 err = fib_nh_common_init(&nh->nh_common, cfg->fc_encap,
535 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
539 nh->fib_nh_oif = cfg->fc_oif;
540 nh->fib_nh_gw_family = cfg->fc_gw_family;
541 if (cfg->fc_gw_family == AF_INET)
542 nh->fib_nh_gw4 = cfg->fc_gw4;
543 else if (cfg->fc_gw_family == AF_INET6)
544 nh->fib_nh_gw6 = cfg->fc_gw6;
546 nh->fib_nh_flags = cfg->fc_flags;
548 #ifdef CONFIG_IP_ROUTE_CLASSID
549 nh->nh_tclassid = cfg->fc_flow;
551 net->ipv4.fib_num_tclassid_users++;
553 #ifdef CONFIG_IP_ROUTE_MULTIPATH
554 nh->fib_nh_weight = nh_weight;
559 #ifdef CONFIG_IP_ROUTE_MULTIPATH
561 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
562 struct netlink_ext_ack *extack)
566 while (rtnh_ok(rtnh, remaining)) {
568 rtnh = rtnh_next(rtnh, &remaining);
571 /* leftover implies invalid nexthop configuration, discard it */
573 NL_SET_ERR_MSG(extack,
574 "Invalid nexthop configuration - extra data after nexthops");
581 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
582 int remaining, struct fib_config *cfg,
583 struct netlink_ext_ack *extack)
585 struct net *net = fi->fib_net;
586 struct fib_config fib_cfg;
589 change_nexthops(fi) {
592 memset(&fib_cfg, 0, sizeof(fib_cfg));
594 if (!rtnh_ok(rtnh, remaining)) {
595 NL_SET_ERR_MSG(extack,
596 "Invalid nexthop configuration - extra data after nexthop");
600 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
601 NL_SET_ERR_MSG(extack,
602 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
606 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
607 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
609 attrlen = rtnh_attrlen(rtnh);
611 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
613 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
614 nlav = nla_find(attrs, attrlen, RTA_VIA);
616 NL_SET_ERR_MSG(extack,
617 "Nexthop configuration can not contain both GATEWAY and VIA");
621 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
623 fib_cfg.fc_gw_family = AF_INET;
625 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
630 nla = nla_find(attrs, attrlen, RTA_FLOW);
632 fib_cfg.fc_flow = nla_get_u32(nla);
634 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
635 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
637 fib_cfg.fc_encap_type = nla_get_u16(nla);
640 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
641 rtnh->rtnh_hops + 1, extack);
645 rtnh = rtnh_next(rtnh, &remaining);
646 } endfor_nexthops(fi);
649 if (cfg->fc_oif && fi->fib_nh->fib_nh_oif != cfg->fc_oif) {
650 NL_SET_ERR_MSG(extack,
651 "Nexthop device index does not match RTA_OIF");
654 if (cfg->fc_gw_family) {
655 if (cfg->fc_gw_family != fi->fib_nh->fib_nh_gw_family ||
656 (cfg->fc_gw_family == AF_INET &&
657 fi->fib_nh->fib_nh_gw4 != cfg->fc_gw4) ||
658 (cfg->fc_gw_family == AF_INET6 &&
659 ipv6_addr_cmp(&fi->fib_nh->fib_nh_gw6, &cfg->fc_gw6))) {
660 NL_SET_ERR_MSG(extack,
661 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
665 #ifdef CONFIG_IP_ROUTE_CLASSID
666 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
667 NL_SET_ERR_MSG(extack,
668 "Nexthop class id does not match RTA_FLOW");
677 static void fib_rebalance(struct fib_info *fi)
687 if (nh->fib_nh_flags & RTNH_F_DEAD)
690 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
691 nh->fib_nh_flags & RTNH_F_LINKDOWN)
694 total += nh->fib_nh_weight;
695 } endfor_nexthops(fi);
698 change_nexthops(fi) {
701 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
703 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
704 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
707 w += nexthop_nh->fib_nh_weight;
708 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
712 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
713 } endfor_nexthops(fi);
715 #else /* CONFIG_IP_ROUTE_MULTIPATH */
717 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
718 int remaining, struct fib_config *cfg,
719 struct netlink_ext_ack *extack)
721 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
726 #define fib_rebalance(fi) do { } while (0)
728 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
730 static int fib_encap_match(u16 encap_type,
731 struct nlattr *encap,
732 const struct fib_nh *nh,
733 const struct fib_config *cfg,
734 struct netlink_ext_ack *extack)
736 struct lwtunnel_state *lwtstate;
739 if (encap_type == LWTUNNEL_ENCAP_NONE)
742 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
743 cfg, &lwtstate, extack);
745 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
746 lwtstate_free(lwtstate);
752 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
753 struct netlink_ext_ack *extack)
755 #ifdef CONFIG_IP_ROUTE_MULTIPATH
756 struct rtnexthop *rtnh;
760 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
763 if (cfg->fc_oif || cfg->fc_gw_family) {
765 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
766 fi->fib_nh, cfg, extack))
769 #ifdef CONFIG_IP_ROUTE_CLASSID
771 cfg->fc_flow != fi->fib_nh->nh_tclassid)
774 if ((cfg->fc_oif && cfg->fc_oif != fi->fib_nh->fib_nh_oif) ||
775 (cfg->fc_gw_family &&
776 cfg->fc_gw_family != fi->fib_nh->fib_nh_gw_family))
779 if (cfg->fc_gw_family == AF_INET &&
780 cfg->fc_gw4 != fi->fib_nh->fib_nh_gw4)
783 if (cfg->fc_gw_family == AF_INET6 &&
784 ipv6_addr_cmp(&cfg->fc_gw6, &fi->fib_nh->fib_nh_gw6))
790 #ifdef CONFIG_IP_ROUTE_MULTIPATH
795 remaining = cfg->fc_mp_len;
800 if (!rtnh_ok(rtnh, remaining))
803 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
806 attrlen = rtnh_attrlen(rtnh);
808 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
810 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
811 nlav = nla_find(attrs, attrlen, RTA_VIA);
813 NL_SET_ERR_MSG(extack,
814 "Nexthop configuration can not contain both GATEWAY and VIA");
819 if (nh->fib_nh_gw_family != AF_INET ||
820 nla_get_in_addr(nla) != nh->fib_nh_gw4)
823 struct fib_config cfg2;
826 err = fib_gw_from_via(&cfg2, nlav, extack);
830 switch (nh->fib_nh_gw_family) {
832 if (cfg2.fc_gw_family != AF_INET ||
833 cfg2.fc_gw4 != nh->fib_nh_gw4)
837 if (cfg2.fc_gw_family != AF_INET6 ||
838 ipv6_addr_cmp(&cfg2.fc_gw6,
845 #ifdef CONFIG_IP_ROUTE_CLASSID
846 nla = nla_find(attrs, attrlen, RTA_FLOW);
847 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
852 rtnh = rtnh_next(rtnh, &remaining);
853 } endfor_nexthops(fi);
858 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
866 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
867 int type = nla_type(nla);
875 if (type == RTAX_CC_ALGO) {
876 char tmp[TCP_CA_NAME_MAX];
879 nla_strlcpy(tmp, nla, sizeof(tmp));
880 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
882 if (nla_len(nla) != sizeof(u32))
884 val = nla_get_u32(nla);
887 fi_val = fi->fib_metrics->metrics[type - 1];
888 if (type == RTAX_FEATURES)
889 fi_val &= ~DST_FEATURE_ECN_CA;
898 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
899 u32 table, struct netlink_ext_ack *extack)
901 struct fib6_config cfg = {
903 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
904 .fc_ifindex = nh->fib_nh_oif,
905 .fc_gateway = nh->fib_nh_gw6,
907 struct fib6_nh fib6_nh = {};
910 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
912 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
913 dev_hold(nh->fib_nh_dev);
914 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
915 nh->fib_nh_scope = RT_SCOPE_LINK;
917 ipv6_stub->fib6_nh_release(&fib6_nh);
927 * Semantics of nexthop is very messy by historical reasons.
928 * We have to take into account, that:
929 * a) gateway can be actually local interface address,
930 * so that gatewayed route is direct.
931 * b) gateway must be on-link address, possibly
932 * described not by an ifaddr, but also by a direct route.
933 * c) If both gateway and interface are specified, they should not
935 * d) If we use tunnel routes, gateway could be not on-link.
937 * Attempt to reconcile all of these (alas, self-contradictory) conditions
938 * results in pretty ugly and hairy code with obscure logic.
940 * I chose to generalized it instead, so that the size
941 * of code does not increase practically, but it becomes
943 * Every prefix is assigned a "scope" value: "host" is local address,
944 * "link" is direct route,
945 * [ ... "site" ... "interior" ... ]
946 * and "universe" is true gateway route with global meaning.
948 * Every prefix refers to a set of "nexthop"s (gw, oif),
949 * where gw must have narrower scope. This recursion stops
950 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
951 * which means that gw is forced to be on link.
953 * Code is still hairy, but now it is apparently logically
954 * consistent and very flexible. F.e. as by-product it allows
955 * to co-exists in peace independent exterior and interior
958 * Normally it looks as following.
960 * {universe prefix} -> (gw, oif) [scope link]
962 * |-> {link prefix} -> (gw, oif) [scope local]
964 * |-> {local prefix} (terminal node)
966 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
967 u8 scope, struct netlink_ext_ack *extack)
969 struct net_device *dev;
970 struct fib_result res;
973 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
974 unsigned int addr_type;
976 if (scope >= RT_SCOPE_LINK) {
977 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
980 dev = __dev_get_by_index(net, nh->fib_nh_oif);
982 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
985 if (!(dev->flags & IFF_UP)) {
986 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
989 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
990 if (addr_type != RTN_UNICAST) {
991 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
994 if (!netif_carrier_ok(dev))
995 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
996 nh->fib_nh_dev = dev;
998 nh->fib_nh_scope = RT_SCOPE_LINK;
1003 struct fib_table *tbl = NULL;
1004 struct flowi4 fl4 = {
1005 .daddr = nh->fib_nh_gw4,
1006 .flowi4_scope = scope + 1,
1007 .flowi4_oif = nh->fib_nh_oif,
1008 .flowi4_iif = LOOPBACK_IFINDEX,
1011 /* It is not necessary, but requires a bit of thinking */
1012 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1013 fl4.flowi4_scope = RT_SCOPE_LINK;
1016 tbl = fib_get_table(net, table);
1019 err = fib_table_lookup(tbl, &fl4, &res,
1020 FIB_LOOKUP_IGNORE_LINKSTATE |
1023 /* on error or if no table given do full lookup. This
1024 * is needed for example when nexthops are in the local
1025 * table rather than the given table
1028 err = fib_lookup(net, &fl4, &res,
1029 FIB_LOOKUP_IGNORE_LINKSTATE);
1033 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1039 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1040 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1043 nh->fib_nh_scope = res.scope;
1044 nh->fib_nh_oif = FIB_RES_OIF(res);
1045 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1047 NL_SET_ERR_MSG(extack,
1048 "No egress device for nexthop gateway");
1052 if (!netif_carrier_ok(dev))
1053 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1054 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1060 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1061 struct netlink_ext_ack *extack)
1063 struct in_device *in_dev;
1066 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1067 NL_SET_ERR_MSG(extack,
1068 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1075 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1079 if (!(in_dev->dev->flags & IFF_UP)) {
1080 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1084 nh->fib_nh_dev = in_dev->dev;
1085 dev_hold(nh->fib_nh_dev);
1086 nh->fib_nh_scope = RT_SCOPE_HOST;
1087 if (!netif_carrier_ok(nh->fib_nh_dev))
1088 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1095 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
1096 struct netlink_ext_ack *extack)
1098 struct net *net = cfg->fc_nlinfo.nl_net;
1099 u32 table = cfg->fc_table;
1102 if (nh->fib_nh_gw_family == AF_INET)
1103 err = fib_check_nh_v4_gw(net, nh, table, cfg->fc_scope, extack);
1104 else if (nh->fib_nh_gw_family == AF_INET6)
1105 err = fib_check_nh_v6_gw(net, nh, table, extack);
1107 err = fib_check_nh_nongw(net, nh, extack);
1112 static inline unsigned int fib_laddr_hashfn(__be32 val)
1114 unsigned int mask = (fib_info_hash_size - 1);
1116 return ((__force u32)val ^
1117 ((__force u32)val >> 7) ^
1118 ((__force u32)val >> 14)) & mask;
1121 static struct hlist_head *fib_info_hash_alloc(int bytes)
1123 if (bytes <= PAGE_SIZE)
1124 return kzalloc(bytes, GFP_KERNEL);
1126 return (struct hlist_head *)
1127 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1131 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1136 if (bytes <= PAGE_SIZE)
1139 free_pages((unsigned long) hash, get_order(bytes));
1142 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1143 struct hlist_head *new_laddrhash,
1144 unsigned int new_size)
1146 struct hlist_head *old_info_hash, *old_laddrhash;
1147 unsigned int old_size = fib_info_hash_size;
1148 unsigned int i, bytes;
1150 spin_lock_bh(&fib_info_lock);
1151 old_info_hash = fib_info_hash;
1152 old_laddrhash = fib_info_laddrhash;
1153 fib_info_hash_size = new_size;
1155 for (i = 0; i < old_size; i++) {
1156 struct hlist_head *head = &fib_info_hash[i];
1157 struct hlist_node *n;
1158 struct fib_info *fi;
1160 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1161 struct hlist_head *dest;
1162 unsigned int new_hash;
1164 new_hash = fib_info_hashfn(fi);
1165 dest = &new_info_hash[new_hash];
1166 hlist_add_head(&fi->fib_hash, dest);
1169 fib_info_hash = new_info_hash;
1171 for (i = 0; i < old_size; i++) {
1172 struct hlist_head *lhead = &fib_info_laddrhash[i];
1173 struct hlist_node *n;
1174 struct fib_info *fi;
1176 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1177 struct hlist_head *ldest;
1178 unsigned int new_hash;
1180 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1181 ldest = &new_laddrhash[new_hash];
1182 hlist_add_head(&fi->fib_lhash, ldest);
1185 fib_info_laddrhash = new_laddrhash;
1187 spin_unlock_bh(&fib_info_lock);
1189 bytes = old_size * sizeof(struct hlist_head *);
1190 fib_info_hash_free(old_info_hash, bytes);
1191 fib_info_hash_free(old_laddrhash, bytes);
1194 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
1196 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev,
1198 nh->nh_parent->fib_scope);
1199 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1201 return nh->nh_saddr;
1204 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1206 struct fib_nh_common *nhc = res->nhc;
1209 if (res->fi->fib_prefsrc)
1210 return res->fi->fib_prefsrc;
1212 nh = container_of(nhc, struct fib_nh, nh_common);
1213 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1214 return nh->nh_saddr;
1216 return fib_info_update_nh_saddr(net, nh);
1219 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1221 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1222 fib_prefsrc != cfg->fc_dst) {
1223 u32 tb_id = cfg->fc_table;
1226 if (tb_id == RT_TABLE_MAIN)
1227 tb_id = RT_TABLE_LOCAL;
1229 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1230 fib_prefsrc, tb_id);
1232 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1233 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1234 fib_prefsrc, RT_TABLE_LOCAL);
1237 if (rc != RTN_LOCAL)
1243 struct fib_info *fib_create_info(struct fib_config *cfg,
1244 struct netlink_ext_ack *extack)
1247 struct fib_info *fi = NULL;
1248 struct fib_info *ofi;
1250 struct net *net = cfg->fc_nlinfo.nl_net;
1252 if (cfg->fc_type > RTN_MAX)
1255 /* Fast check to catch the most weird cases */
1256 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1257 NL_SET_ERR_MSG(extack, "Invalid scope");
1261 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1262 NL_SET_ERR_MSG(extack,
1263 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1267 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1269 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1276 if (fib_info_cnt >= fib_info_hash_size) {
1277 unsigned int new_size = fib_info_hash_size << 1;
1278 struct hlist_head *new_info_hash;
1279 struct hlist_head *new_laddrhash;
1284 bytes = new_size * sizeof(struct hlist_head *);
1285 new_info_hash = fib_info_hash_alloc(bytes);
1286 new_laddrhash = fib_info_hash_alloc(bytes);
1287 if (!new_info_hash || !new_laddrhash) {
1288 fib_info_hash_free(new_info_hash, bytes);
1289 fib_info_hash_free(new_laddrhash, bytes);
1291 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1293 if (!fib_info_hash_size)
1297 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1300 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1301 cfg->fc_mx_len, extack);
1302 if (unlikely(IS_ERR(fi->fib_metrics))) {
1303 err = PTR_ERR(fi->fib_metrics);
1305 return ERR_PTR(err);
1310 fi->fib_protocol = cfg->fc_protocol;
1311 fi->fib_scope = cfg->fc_scope;
1312 fi->fib_flags = cfg->fc_flags;
1313 fi->fib_priority = cfg->fc_priority;
1314 fi->fib_prefsrc = cfg->fc_prefsrc;
1315 fi->fib_type = cfg->fc_type;
1316 fi->fib_tb_id = cfg->fc_table;
1319 change_nexthops(fi) {
1320 nexthop_nh->nh_parent = fi;
1321 } endfor_nexthops(fi)
1324 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1326 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1331 if (fib_props[cfg->fc_type].error) {
1332 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1333 NL_SET_ERR_MSG(extack,
1334 "Gateway, device and multipath can not be specified for this route type");
1339 switch (cfg->fc_type) {
1347 NL_SET_ERR_MSG(extack, "Invalid route type");
1352 if (cfg->fc_scope > RT_SCOPE_HOST) {
1353 NL_SET_ERR_MSG(extack, "Invalid scope");
1357 if (cfg->fc_scope == RT_SCOPE_HOST) {
1358 struct fib_nh *nh = fi->fib_nh;
1360 /* Local address is added. */
1362 NL_SET_ERR_MSG(extack,
1363 "Route with host scope can not have multiple nexthops");
1366 if (nh->fib_nh_gw_family) {
1367 NL_SET_ERR_MSG(extack,
1368 "Route with host scope can not have a gateway");
1371 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1372 nh->fib_nh_dev = dev_get_by_index(net, fi->fib_nh->fib_nh_oif);
1374 if (!nh->fib_nh_dev)
1379 change_nexthops(fi) {
1380 err = fib_check_nh(cfg, nexthop_nh, extack);
1383 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1385 } endfor_nexthops(fi)
1386 if (linkdown == fi->fib_nhs)
1387 fi->fib_flags |= RTNH_F_LINKDOWN;
1390 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1391 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1395 change_nexthops(fi) {
1396 fib_info_update_nh_saddr(net, nexthop_nh);
1397 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1398 fi->fib_nh_is_v6 = true;
1399 } endfor_nexthops(fi)
1404 ofi = fib_find_info(fi);
1413 refcount_set(&fi->fib_clntref, 1);
1414 spin_lock_bh(&fib_info_lock);
1415 hlist_add_head(&fi->fib_hash,
1416 &fib_info_hash[fib_info_hashfn(fi)]);
1417 if (fi->fib_prefsrc) {
1418 struct hlist_head *head;
1420 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1421 hlist_add_head(&fi->fib_lhash, head);
1423 change_nexthops(fi) {
1424 struct hlist_head *head;
1427 if (!nexthop_nh->fib_nh_dev)
1429 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1430 head = &fib_info_devhash[hash];
1431 hlist_add_head(&nexthop_nh->nh_hash, head);
1432 } endfor_nexthops(fi)
1433 spin_unlock_bh(&fib_info_lock);
1445 return ERR_PTR(err);
1448 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1449 unsigned char *flags, bool skip_oif)
1451 if (nhc->nhc_flags & RTNH_F_DEAD)
1452 *flags |= RTNH_F_DEAD;
1454 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1455 *flags |= RTNH_F_LINKDOWN;
1458 switch (nhc->nhc_family) {
1460 if (ip_ignore_linkdown(nhc->nhc_dev))
1461 *flags |= RTNH_F_DEAD;
1464 if (ip6_ignore_linkdown(nhc->nhc_dev))
1465 *flags |= RTNH_F_DEAD;
1471 switch (nhc->nhc_gw_family) {
1473 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1474 goto nla_put_failure;
1477 /* if gateway family does not match nexthop family
1478 * gateway is encoded as RTA_VIA
1480 if (nhc->nhc_gw_family != nhc->nhc_family) {
1481 int alen = sizeof(struct in6_addr);
1485 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1487 goto nla_put_failure;
1489 via = nla_data(nla);
1490 via->rtvia_family = AF_INET6;
1491 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1492 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1493 &nhc->nhc_gw.ipv6) < 0) {
1494 goto nla_put_failure;
1499 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1500 if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1501 *flags |= RTNH_F_OFFLOAD;
1503 if (!skip_oif && nhc->nhc_dev &&
1504 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1505 goto nla_put_failure;
1507 if (nhc->nhc_lwtstate &&
1508 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1509 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1510 goto nla_put_failure;
1517 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1519 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1520 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1523 const struct net_device *dev = nhc->nhc_dev;
1524 struct rtnexthop *rtnh;
1525 unsigned char flags = 0;
1527 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1529 goto nla_put_failure;
1531 rtnh->rtnh_hops = nh_weight - 1;
1532 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1534 if (fib_nexthop_info(skb, nhc, &flags, true) < 0)
1535 goto nla_put_failure;
1537 rtnh->rtnh_flags = flags;
1539 /* length of rtnetlink header + attributes */
1540 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1547 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1550 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1551 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1555 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1557 goto nla_put_failure;
1560 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight) < 0)
1561 goto nla_put_failure;
1562 #ifdef CONFIG_IP_ROUTE_CLASSID
1563 if (nh->nh_tclassid &&
1564 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1565 goto nla_put_failure;
1567 } endfor_nexthops(fi);
1569 nla_nest_end(skb, mp);
1577 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1583 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1584 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1585 struct fib_info *fi, unsigned int flags)
1587 struct nlmsghdr *nlh;
1590 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1594 rtm = nlmsg_data(nlh);
1595 rtm->rtm_family = AF_INET;
1596 rtm->rtm_dst_len = dst_len;
1597 rtm->rtm_src_len = 0;
1600 rtm->rtm_table = tb_id;
1602 rtm->rtm_table = RT_TABLE_COMPAT;
1603 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1604 goto nla_put_failure;
1605 rtm->rtm_type = type;
1606 rtm->rtm_flags = fi->fib_flags;
1607 rtm->rtm_scope = fi->fib_scope;
1608 rtm->rtm_protocol = fi->fib_protocol;
1610 if (rtm->rtm_dst_len &&
1611 nla_put_in_addr(skb, RTA_DST, dst))
1612 goto nla_put_failure;
1613 if (fi->fib_priority &&
1614 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1615 goto nla_put_failure;
1616 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1617 goto nla_put_failure;
1619 if (fi->fib_prefsrc &&
1620 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1621 goto nla_put_failure;
1622 if (fi->fib_nhs == 1) {
1623 struct fib_nh *nh = &fi->fib_nh[0];
1624 unsigned char flags = 0;
1626 if (fib_nexthop_info(skb, &nh->nh_common, &flags, false) < 0)
1627 goto nla_put_failure;
1629 rtm->rtm_flags = flags;
1630 #ifdef CONFIG_IP_ROUTE_CLASSID
1631 if (nh->nh_tclassid &&
1632 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1633 goto nla_put_failure;
1636 if (fib_add_multipath(skb, fi) < 0)
1637 goto nla_put_failure;
1640 nlmsg_end(skb, nlh);
1644 nlmsg_cancel(skb, nlh);
1650 * - local address disappeared -> we must delete all the entries
1652 * - device went down -> we must shutdown all nexthops going via it.
1654 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1657 unsigned int hash = fib_laddr_hashfn(local);
1658 struct hlist_head *head = &fib_info_laddrhash[hash];
1659 struct net *net = dev_net(dev);
1660 int tb_id = l3mdev_fib_table(dev);
1661 struct fib_info *fi;
1663 if (!fib_info_laddrhash || local == 0)
1666 hlist_for_each_entry(fi, head, fib_lhash) {
1667 if (!net_eq(fi->fib_net, net) ||
1668 fi->fib_tb_id != tb_id)
1670 if (fi->fib_prefsrc == local) {
1671 fi->fib_flags |= RTNH_F_DEAD;
1678 static int call_fib_nh_notifiers(struct fib_nh *nh,
1679 enum fib_event_type event_type)
1681 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1682 struct fib_nh_notifier_info info = {
1686 switch (event_type) {
1687 case FIB_EVENT_NH_ADD:
1688 if (nh->fib_nh_flags & RTNH_F_DEAD)
1690 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1692 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1694 case FIB_EVENT_NH_DEL:
1695 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1696 (nh->fib_nh_flags & RTNH_F_DEAD))
1697 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1698 event_type, &info.info);
1706 /* Update the PMTU of exceptions when:
1707 * - the new MTU of the first hop becomes smaller than the PMTU
1708 * - the old MTU was the same as the PMTU, and it limited discovery of
1709 * larger MTUs on the path. With that limit raised, we can now
1710 * discover larger MTUs
1711 * A special case is locked exceptions, for which the PMTU is smaller
1712 * than the minimal accepted PMTU:
1713 * - if the new MTU is greater than the PMTU, don't make any change
1714 * - otherwise, unlock and set PMTU
1716 static void nh_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1718 struct fnhe_hash_bucket *bucket;
1721 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1725 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1726 struct fib_nh_exception *fnhe;
1728 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1730 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1731 if (fnhe->fnhe_mtu_locked) {
1732 if (new <= fnhe->fnhe_pmtu) {
1733 fnhe->fnhe_pmtu = new;
1734 fnhe->fnhe_mtu_locked = false;
1736 } else if (new < fnhe->fnhe_pmtu ||
1737 orig == fnhe->fnhe_pmtu) {
1738 fnhe->fnhe_pmtu = new;
1744 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1746 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1747 struct hlist_head *head = &fib_info_devhash[hash];
1750 hlist_for_each_entry(nh, head, nh_hash) {
1751 if (nh->fib_nh_dev == dev)
1752 nh_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1756 /* Event force Flags Description
1757 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1758 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1759 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1760 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1762 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1765 int scope = RT_SCOPE_NOWHERE;
1766 struct fib_info *prev_fi = NULL;
1767 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1768 struct hlist_head *head = &fib_info_devhash[hash];
1774 hlist_for_each_entry(nh, head, nh_hash) {
1775 struct fib_info *fi = nh->nh_parent;
1778 BUG_ON(!fi->fib_nhs);
1779 if (nh->fib_nh_dev != dev || fi == prev_fi)
1783 change_nexthops(fi) {
1784 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1786 else if (nexthop_nh->fib_nh_dev == dev &&
1787 nexthop_nh->fib_nh_scope != scope) {
1790 case NETDEV_UNREGISTER:
1791 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1794 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1797 call_fib_nh_notifiers(nexthop_nh,
1801 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1802 if (event == NETDEV_UNREGISTER &&
1803 nexthop_nh->fib_nh_dev == dev) {
1808 } endfor_nexthops(fi)
1809 if (dead == fi->fib_nhs) {
1812 case NETDEV_UNREGISTER:
1813 fi->fib_flags |= RTNH_F_DEAD;
1816 fi->fib_flags |= RTNH_F_LINKDOWN;
1828 /* Must be invoked inside of an RCU protected region. */
1829 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1831 struct fib_info *fi = NULL, *last_resort = NULL;
1832 struct hlist_head *fa_head = res->fa_head;
1833 struct fib_table *tb = res->table;
1834 u8 slen = 32 - res->prefixlen;
1835 int order = -1, last_idx = -1;
1836 struct fib_alias *fa, *fa1 = NULL;
1837 u32 last_prio = res->fi->fib_priority;
1840 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1841 struct fib_info *next_fi = fa->fa_info;
1843 if (fa->fa_slen != slen)
1845 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1847 if (fa->tb_id != tb->tb_id)
1849 if (next_fi->fib_priority > last_prio &&
1850 fa->fa_tos == last_tos) {
1855 if (next_fi->fib_flags & RTNH_F_DEAD)
1857 last_tos = fa->fa_tos;
1858 last_prio = next_fi->fib_priority;
1860 if (next_fi->fib_scope != res->scope ||
1861 fa->fa_type != RTN_UNICAST)
1863 if (!next_fi->fib_nh[0].fib_nh_gw4 ||
1864 next_fi->fib_nh[0].fib_nh_scope != RT_SCOPE_LINK)
1867 fib_alias_accessed(fa);
1870 if (next_fi != res->fi)
1873 } else if (!fib_detect_death(fi, order, &last_resort,
1874 &last_idx, fa1->fa_default)) {
1875 fib_result_assign(res, fi);
1876 fa1->fa_default = order;
1883 if (order <= 0 || !fi) {
1885 fa1->fa_default = -1;
1889 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1891 fib_result_assign(res, fi);
1892 fa1->fa_default = order;
1897 fib_result_assign(res, last_resort);
1898 fa1->fa_default = last_idx;
1904 * Dead device goes up. We wake up dead nexthops.
1905 * It takes sense only on multipath routes.
1907 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
1909 struct fib_info *prev_fi;
1911 struct hlist_head *head;
1915 if (!(dev->flags & IFF_UP))
1918 if (nh_flags & RTNH_F_DEAD) {
1919 unsigned int flags = dev_get_flags(dev);
1921 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1922 nh_flags |= RTNH_F_LINKDOWN;
1926 hash = fib_devindex_hashfn(dev->ifindex);
1927 head = &fib_info_devhash[hash];
1930 hlist_for_each_entry(nh, head, nh_hash) {
1931 struct fib_info *fi = nh->nh_parent;
1934 BUG_ON(!fi->fib_nhs);
1935 if (nh->fib_nh_dev != dev || fi == prev_fi)
1940 change_nexthops(fi) {
1941 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
1945 if (!nexthop_nh->fib_nh_dev ||
1946 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
1948 if (nexthop_nh->fib_nh_dev != dev ||
1949 !__in_dev_get_rtnl(dev))
1952 nexthop_nh->fib_nh_flags &= ~nh_flags;
1953 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1954 } endfor_nexthops(fi)
1957 fi->fib_flags &= ~nh_flags;
1967 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1968 static bool fib_good_nh(const struct fib_nh *nh)
1970 int state = NUD_REACHABLE;
1972 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
1973 struct neighbour *n;
1977 if (likely(nh->fib_nh_gw_family == AF_INET))
1978 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
1979 (__force u32)nh->fib_nh_gw4);
1980 else if (nh->fib_nh_gw_family == AF_INET6)
1981 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
1986 state = n->nud_state;
1988 rcu_read_unlock_bh();
1991 return !!(state & NUD_VALID);
1994 void fib_select_multipath(struct fib_result *res, int hash)
1996 struct fib_info *fi = res->fi;
1997 struct net *net = fi->fib_net;
2000 change_nexthops(fi) {
2001 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2002 if (!fib_good_nh(nexthop_nh))
2005 res->nh_sel = nhsel;
2006 res->nhc = &nexthop_nh->nh_common;
2011 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2014 res->nh_sel = nhsel;
2015 res->nhc = &nexthop_nh->nh_common;
2017 } endfor_nexthops(fi);
2021 void fib_select_path(struct net *net, struct fib_result *res,
2022 struct flowi4 *fl4, const struct sk_buff *skb)
2024 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2027 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2028 if (res->fi->fib_nhs > 1) {
2029 int h = fib_multipath_hash(net, fl4, skb, NULL);
2031 fib_select_multipath(res, h);
2035 if (!res->prefixlen &&
2036 res->table->tb_num_default > 1 &&
2037 res->type == RTN_UNICAST)
2038 fib_select_default(fl4, res);
2042 fl4->saddr = fib_result_prefsrc(net, res);