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/netlink.h>
45 #include <net/nexthop.h>
46 #include <net/lwtunnel.h>
48 #include "fib_lookup.h"
50 static DEFINE_SPINLOCK(fib_info_lock);
51 static struct hlist_head *fib_info_hash;
52 static struct hlist_head *fib_info_laddrhash;
53 static unsigned int fib_info_hash_size;
54 static unsigned int fib_info_cnt;
56 #define DEVINDEX_HASHBITS 8
57 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
58 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
60 #ifdef CONFIG_IP_ROUTE_MULTIPATH
62 #define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
68 #define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
74 #else /* CONFIG_IP_ROUTE_MULTIPATH */
76 /* Hope, that gcc will optimize it to get rid of dummy loop */
78 #define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
82 #define change_nexthops(fi) { \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
87 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
89 #define endfor_nexthops(fi) }
92 const struct fib_prop fib_props[RTN_MAX + 1] = {
95 .scope = RT_SCOPE_NOWHERE,
99 .scope = RT_SCOPE_UNIVERSE,
103 .scope = RT_SCOPE_HOST,
107 .scope = RT_SCOPE_LINK,
111 .scope = RT_SCOPE_LINK,
115 .scope = RT_SCOPE_UNIVERSE,
119 .scope = RT_SCOPE_UNIVERSE,
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
127 .scope = RT_SCOPE_UNIVERSE,
131 .scope = RT_SCOPE_UNIVERSE,
135 .scope = RT_SCOPE_NOWHERE,
139 .scope = RT_SCOPE_NOWHERE,
143 static void rt_fibinfo_free(struct rtable __rcu **rtp)
145 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
151 * because we waited an RCU grace period before calling
152 * free_fib_info_rcu()
155 dst_dev_put(&rt->dst);
156 dst_release_immediate(&rt->dst);
159 static void free_nh_exceptions(struct fib_nh *nh)
161 struct fnhe_hash_bucket *hash;
164 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
167 for (i = 0; i < FNHE_HASH_SIZE; i++) {
168 struct fib_nh_exception *fnhe;
170 fnhe = rcu_dereference_protected(hash[i].chain, 1);
172 struct fib_nh_exception *next;
174 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
176 rt_fibinfo_free(&fnhe->fnhe_rth_input);
177 rt_fibinfo_free(&fnhe->fnhe_rth_output);
187 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
194 for_each_possible_cpu(cpu) {
197 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
199 dst_dev_put(&rt->dst);
200 dst_release_immediate(&rt->dst);
206 /* Release a nexthop info record */
207 static void free_fib_info_rcu(struct rcu_head *head)
209 struct fib_info *fi = container_of(head, struct fib_info, rcu);
210 struct dst_metrics *m;
212 change_nexthops(fi) {
213 if (nexthop_nh->nh_dev)
214 dev_put(nexthop_nh->nh_dev);
215 lwtstate_put(nexthop_nh->nh_lwtstate);
216 free_nh_exceptions(nexthop_nh);
217 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
218 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
219 } endfor_nexthops(fi);
222 if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
227 void free_fib_info(struct fib_info *fi)
229 if (fi->fib_dead == 0) {
230 pr_warn("Freeing alive fib_info %p\n", fi);
234 #ifdef CONFIG_IP_ROUTE_CLASSID
235 change_nexthops(fi) {
236 if (nexthop_nh->nh_tclassid)
237 fi->fib_net->ipv4.fib_num_tclassid_users--;
238 } endfor_nexthops(fi);
240 call_rcu(&fi->rcu, free_fib_info_rcu);
242 EXPORT_SYMBOL_GPL(free_fib_info);
244 void fib_release_info(struct fib_info *fi)
246 spin_lock_bh(&fib_info_lock);
247 if (fi && --fi->fib_treeref == 0) {
248 hlist_del(&fi->fib_hash);
250 hlist_del(&fi->fib_lhash);
251 change_nexthops(fi) {
252 if (!nexthop_nh->nh_dev)
254 hlist_del(&nexthop_nh->nh_hash);
255 } endfor_nexthops(fi)
259 spin_unlock_bh(&fib_info_lock);
262 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
264 const struct fib_nh *onh = ofi->fib_nh;
267 if (nh->nh_oif != onh->nh_oif ||
268 nh->nh_gw != onh->nh_gw ||
269 nh->nh_scope != onh->nh_scope ||
270 #ifdef CONFIG_IP_ROUTE_MULTIPATH
271 nh->nh_weight != onh->nh_weight ||
273 #ifdef CONFIG_IP_ROUTE_CLASSID
274 nh->nh_tclassid != onh->nh_tclassid ||
276 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
277 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
280 } endfor_nexthops(fi);
284 static inline unsigned int fib_devindex_hashfn(unsigned int val)
286 unsigned int mask = DEVINDEX_HASHSIZE - 1;
289 (val >> DEVINDEX_HASHBITS) ^
290 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
293 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
295 unsigned int mask = (fib_info_hash_size - 1);
296 unsigned int val = fi->fib_nhs;
298 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
299 val ^= (__force u32)fi->fib_prefsrc;
300 val ^= fi->fib_priority;
302 val ^= fib_devindex_hashfn(nh->nh_oif);
303 } endfor_nexthops(fi)
305 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
308 static struct fib_info *fib_find_info(const struct fib_info *nfi)
310 struct hlist_head *head;
314 hash = fib_info_hashfn(nfi);
315 head = &fib_info_hash[hash];
317 hlist_for_each_entry(fi, head, fib_hash) {
318 if (!net_eq(fi->fib_net, nfi->fib_net))
320 if (fi->fib_nhs != nfi->fib_nhs)
322 if (nfi->fib_protocol == fi->fib_protocol &&
323 nfi->fib_scope == fi->fib_scope &&
324 nfi->fib_prefsrc == fi->fib_prefsrc &&
325 nfi->fib_priority == fi->fib_priority &&
326 nfi->fib_type == fi->fib_type &&
327 memcmp(nfi->fib_metrics, fi->fib_metrics,
328 sizeof(u32) * RTAX_MAX) == 0 &&
329 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
330 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
337 /* Check, that the gateway is already configured.
338 * Used only by redirect accept routine.
340 int ip_fib_check_default(__be32 gw, struct net_device *dev)
342 struct hlist_head *head;
346 spin_lock(&fib_info_lock);
348 hash = fib_devindex_hashfn(dev->ifindex);
349 head = &fib_info_devhash[hash];
350 hlist_for_each_entry(nh, head, nh_hash) {
351 if (nh->nh_dev == dev &&
353 !(nh->nh_flags & RTNH_F_DEAD)) {
354 spin_unlock(&fib_info_lock);
359 spin_unlock(&fib_info_lock);
364 static inline size_t fib_nlmsg_size(struct fib_info *fi)
366 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
367 + nla_total_size(4) /* RTA_TABLE */
368 + nla_total_size(4) /* RTA_DST */
369 + nla_total_size(4) /* RTA_PRIORITY */
370 + nla_total_size(4) /* RTA_PREFSRC */
371 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
373 /* space for nested metrics */
374 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
377 size_t nh_encapsize = 0;
378 /* Also handles the special case fib_nhs == 1 */
380 /* each nexthop is packed in an attribute */
381 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
383 /* may contain flow and gateway attribute */
384 nhsize += 2 * nla_total_size(4);
386 /* grab encap info */
388 if (nh->nh_lwtstate) {
390 nh_encapsize += lwtunnel_get_encap_size(
393 nh_encapsize += nla_total_size(2);
395 } endfor_nexthops(fi);
397 /* all nexthops are packed in a nested attribute */
398 payload += nla_total_size((fi->fib_nhs * nhsize) +
406 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
407 int dst_len, u32 tb_id, const struct nl_info *info,
408 unsigned int nlm_flags)
411 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
414 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
418 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
419 fa->fa_type, key, dst_len,
420 fa->fa_tos, fa->fa_info, nlm_flags);
422 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
423 WARN_ON(err == -EMSGSIZE);
427 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
428 info->nlh, GFP_KERNEL);
432 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
435 static int fib_detect_death(struct fib_info *fi, int order,
436 struct fib_info **last_resort, int *last_idx,
440 int state = NUD_NONE;
442 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
444 state = n->nud_state;
449 if (state == NUD_REACHABLE)
451 if ((state & NUD_VALID) && order != dflt)
453 if ((state & NUD_VALID) ||
454 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
461 #ifdef CONFIG_IP_ROUTE_MULTIPATH
463 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
464 struct netlink_ext_ack *extack)
468 while (rtnh_ok(rtnh, remaining)) {
470 rtnh = rtnh_next(rtnh, &remaining);
473 /* leftover implies invalid nexthop configuration, discard it */
475 NL_SET_ERR_MSG(extack,
476 "Invalid nexthop configuration - extra data after nexthops");
483 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
484 int remaining, struct fib_config *cfg,
485 struct netlink_ext_ack *extack)
489 change_nexthops(fi) {
492 if (!rtnh_ok(rtnh, remaining)) {
493 NL_SET_ERR_MSG(extack,
494 "Invalid nexthop configuration - extra data after nexthop");
498 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
499 NL_SET_ERR_MSG(extack,
500 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
504 nexthop_nh->nh_flags =
505 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
506 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
507 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
509 attrlen = rtnh_attrlen(rtnh);
511 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
513 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
514 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
515 #ifdef CONFIG_IP_ROUTE_CLASSID
516 nla = nla_find(attrs, attrlen, RTA_FLOW);
517 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
518 if (nexthop_nh->nh_tclassid)
519 fi->fib_net->ipv4.fib_num_tclassid_users++;
521 nla = nla_find(attrs, attrlen, RTA_ENCAP);
523 struct lwtunnel_state *lwtstate;
524 struct nlattr *nla_entype;
526 nla_entype = nla_find(attrs, attrlen,
529 NL_SET_BAD_ATTR(extack, nla);
530 NL_SET_ERR_MSG(extack,
531 "Encap type is missing");
535 ret = lwtunnel_build_state(nla_get_u16(
541 nexthop_nh->nh_lwtstate =
542 lwtstate_get(lwtstate);
546 rtnh = rtnh_next(rtnh, &remaining);
547 } endfor_nexthops(fi);
558 static void fib_rebalance(struct fib_info *fi)
562 struct in_device *in_dev;
569 if (nh->nh_flags & RTNH_F_DEAD)
572 in_dev = __in_dev_get_rtnl(nh->nh_dev);
575 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
576 nh->nh_flags & RTNH_F_LINKDOWN)
579 total += nh->nh_weight;
580 } endfor_nexthops(fi);
583 change_nexthops(fi) {
586 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
588 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
591 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
592 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
595 w += nexthop_nh->nh_weight;
596 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
600 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
601 } endfor_nexthops(fi);
604 static inline void fib_add_weight(struct fib_info *fi,
605 const struct fib_nh *nh)
607 fi->fib_weight += nh->nh_weight;
610 #else /* CONFIG_IP_ROUTE_MULTIPATH */
612 #define fib_rebalance(fi) do { } while (0)
613 #define fib_add_weight(fi, nh) do { } while (0)
615 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
617 static int fib_encap_match(u16 encap_type,
618 struct nlattr *encap,
619 const struct fib_nh *nh,
620 const struct fib_config *cfg,
621 struct netlink_ext_ack *extack)
623 struct lwtunnel_state *lwtstate;
626 if (encap_type == LWTUNNEL_ENCAP_NONE)
629 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
630 cfg, &lwtstate, extack);
632 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
633 lwtstate_free(lwtstate);
639 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
640 struct netlink_ext_ack *extack)
642 #ifdef CONFIG_IP_ROUTE_MULTIPATH
643 struct rtnexthop *rtnh;
647 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
650 if (cfg->fc_oif || cfg->fc_gw) {
652 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
653 fi->fib_nh, cfg, extack))
656 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
657 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
662 #ifdef CONFIG_IP_ROUTE_MULTIPATH
667 remaining = cfg->fc_mp_len;
672 if (!rtnh_ok(rtnh, remaining))
675 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
678 attrlen = rtnh_attrlen(rtnh);
680 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
682 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
683 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
685 #ifdef CONFIG_IP_ROUTE_CLASSID
686 nla = nla_find(attrs, attrlen, RTA_FLOW);
687 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
692 rtnh = rtnh_next(rtnh, &remaining);
693 } endfor_nexthops(fi);
703 * Semantics of nexthop is very messy by historical reasons.
704 * We have to take into account, that:
705 * a) gateway can be actually local interface address,
706 * so that gatewayed route is direct.
707 * b) gateway must be on-link address, possibly
708 * described not by an ifaddr, but also by a direct route.
709 * c) If both gateway and interface are specified, they should not
711 * d) If we use tunnel routes, gateway could be not on-link.
713 * Attempt to reconcile all of these (alas, self-contradictory) conditions
714 * results in pretty ugly and hairy code with obscure logic.
716 * I chose to generalized it instead, so that the size
717 * of code does not increase practically, but it becomes
719 * Every prefix is assigned a "scope" value: "host" is local address,
720 * "link" is direct route,
721 * [ ... "site" ... "interior" ... ]
722 * and "universe" is true gateway route with global meaning.
724 * Every prefix refers to a set of "nexthop"s (gw, oif),
725 * where gw must have narrower scope. This recursion stops
726 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
727 * which means that gw is forced to be on link.
729 * Code is still hairy, but now it is apparently logically
730 * consistent and very flexible. F.e. as by-product it allows
731 * to co-exists in peace independent exterior and interior
734 * Normally it looks as following.
736 * {universe prefix} -> (gw, oif) [scope link]
738 * |-> {link prefix} -> (gw, oif) [scope local]
740 * |-> {local prefix} (terminal node)
742 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
743 struct fib_nh *nh, struct netlink_ext_ack *extack)
747 struct net_device *dev;
749 net = cfg->fc_nlinfo.nl_net;
751 struct fib_result res;
753 if (nh->nh_flags & RTNH_F_ONLINK) {
754 unsigned int addr_type;
756 if (cfg->fc_scope >= RT_SCOPE_LINK) {
757 NL_SET_ERR_MSG(extack,
758 "Nexthop has invalid scope");
761 dev = __dev_get_by_index(net, nh->nh_oif);
764 if (!(dev->flags & IFF_UP)) {
765 NL_SET_ERR_MSG(extack,
766 "Nexthop device is not up");
769 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
770 if (addr_type != RTN_UNICAST) {
771 NL_SET_ERR_MSG(extack,
772 "Nexthop has invalid gateway");
775 if (!netif_carrier_ok(dev))
776 nh->nh_flags |= RTNH_F_LINKDOWN;
779 nh->nh_scope = RT_SCOPE_LINK;
784 struct fib_table *tbl = NULL;
785 struct flowi4 fl4 = {
787 .flowi4_scope = cfg->fc_scope + 1,
788 .flowi4_oif = nh->nh_oif,
789 .flowi4_iif = LOOPBACK_IFINDEX,
792 /* It is not necessary, but requires a bit of thinking */
793 if (fl4.flowi4_scope < RT_SCOPE_LINK)
794 fl4.flowi4_scope = RT_SCOPE_LINK;
797 tbl = fib_get_table(net, cfg->fc_table);
800 err = fib_table_lookup(tbl, &fl4, &res,
801 FIB_LOOKUP_IGNORE_LINKSTATE |
804 /* on error or if no table given do full lookup. This
805 * is needed for example when nexthops are in the local
806 * table rather than the given table
809 err = fib_lookup(net, &fl4, &res,
810 FIB_LOOKUP_IGNORE_LINKSTATE);
814 NL_SET_ERR_MSG(extack,
815 "Nexthop has invalid gateway");
821 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
822 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
825 nh->nh_scope = res.scope;
826 nh->nh_oif = FIB_RES_OIF(res);
827 nh->nh_dev = dev = FIB_RES_DEV(res);
829 NL_SET_ERR_MSG(extack,
830 "No egress device for nexthop gateway");
834 if (!netif_carrier_ok(dev))
835 nh->nh_flags |= RTNH_F_LINKDOWN;
836 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
838 struct in_device *in_dev;
840 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
841 NL_SET_ERR_MSG(extack,
842 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
847 in_dev = inetdev_by_index(net, nh->nh_oif);
851 if (!(in_dev->dev->flags & IFF_UP)) {
852 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
855 nh->nh_dev = in_dev->dev;
856 dev_hold(nh->nh_dev);
857 nh->nh_scope = RT_SCOPE_HOST;
858 if (!netif_carrier_ok(nh->nh_dev))
859 nh->nh_flags |= RTNH_F_LINKDOWN;
867 static inline unsigned int fib_laddr_hashfn(__be32 val)
869 unsigned int mask = (fib_info_hash_size - 1);
871 return ((__force u32)val ^
872 ((__force u32)val >> 7) ^
873 ((__force u32)val >> 14)) & mask;
876 static struct hlist_head *fib_info_hash_alloc(int bytes)
878 if (bytes <= PAGE_SIZE)
879 return kzalloc(bytes, GFP_KERNEL);
881 return (struct hlist_head *)
882 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
886 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
891 if (bytes <= PAGE_SIZE)
894 free_pages((unsigned long) hash, get_order(bytes));
897 static void fib_info_hash_move(struct hlist_head *new_info_hash,
898 struct hlist_head *new_laddrhash,
899 unsigned int new_size)
901 struct hlist_head *old_info_hash, *old_laddrhash;
902 unsigned int old_size = fib_info_hash_size;
903 unsigned int i, bytes;
905 spin_lock_bh(&fib_info_lock);
906 old_info_hash = fib_info_hash;
907 old_laddrhash = fib_info_laddrhash;
908 fib_info_hash_size = new_size;
910 for (i = 0; i < old_size; i++) {
911 struct hlist_head *head = &fib_info_hash[i];
912 struct hlist_node *n;
915 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
916 struct hlist_head *dest;
917 unsigned int new_hash;
919 new_hash = fib_info_hashfn(fi);
920 dest = &new_info_hash[new_hash];
921 hlist_add_head(&fi->fib_hash, dest);
924 fib_info_hash = new_info_hash;
926 for (i = 0; i < old_size; i++) {
927 struct hlist_head *lhead = &fib_info_laddrhash[i];
928 struct hlist_node *n;
931 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
932 struct hlist_head *ldest;
933 unsigned int new_hash;
935 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
936 ldest = &new_laddrhash[new_hash];
937 hlist_add_head(&fi->fib_lhash, ldest);
940 fib_info_laddrhash = new_laddrhash;
942 spin_unlock_bh(&fib_info_lock);
944 bytes = old_size * sizeof(struct hlist_head *);
945 fib_info_hash_free(old_info_hash, bytes);
946 fib_info_hash_free(old_laddrhash, bytes);
949 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
951 nh->nh_saddr = inet_select_addr(nh->nh_dev,
953 nh->nh_parent->fib_scope);
954 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
959 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
961 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
962 fib_prefsrc != cfg->fc_dst) {
963 u32 tb_id = cfg->fc_table;
966 if (tb_id == RT_TABLE_MAIN)
967 tb_id = RT_TABLE_LOCAL;
969 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
972 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
973 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
974 fib_prefsrc, RT_TABLE_LOCAL);
984 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
993 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
994 int type = nla_type(nla);
1002 if (type == RTAX_CC_ALGO) {
1003 char tmp[TCP_CA_NAME_MAX];
1005 nla_strlcpy(tmp, nla, sizeof(tmp));
1006 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
1007 if (val == TCP_CA_UNSPEC)
1010 val = nla_get_u32(nla);
1012 if (type == RTAX_ADVMSS && val > 65535 - 40)
1014 if (type == RTAX_MTU && val > 65535 - 15)
1016 if (type == RTAX_HOPLIMIT && val > 255)
1018 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1020 fi->fib_metrics->metrics[type - 1] = val;
1024 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1029 struct fib_info *fib_create_info(struct fib_config *cfg,
1030 struct netlink_ext_ack *extack)
1033 struct fib_info *fi = NULL;
1034 struct fib_info *ofi;
1036 struct net *net = cfg->fc_nlinfo.nl_net;
1038 if (cfg->fc_type > RTN_MAX)
1041 /* Fast check to catch the most weird cases */
1042 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1043 NL_SET_ERR_MSG(extack, "Invalid scope");
1047 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1048 NL_SET_ERR_MSG(extack,
1049 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1053 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1055 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1062 if (fib_info_cnt >= fib_info_hash_size) {
1063 unsigned int new_size = fib_info_hash_size << 1;
1064 struct hlist_head *new_info_hash;
1065 struct hlist_head *new_laddrhash;
1070 bytes = new_size * sizeof(struct hlist_head *);
1071 new_info_hash = fib_info_hash_alloc(bytes);
1072 new_laddrhash = fib_info_hash_alloc(bytes);
1073 if (!new_info_hash || !new_laddrhash) {
1074 fib_info_hash_free(new_info_hash, bytes);
1075 fib_info_hash_free(new_laddrhash, bytes);
1077 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1079 if (!fib_info_hash_size)
1083 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1088 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1089 if (!fi->fib_metrics)
1091 atomic_set(&fi->fib_metrics->refcnt, 1);
1093 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1096 fi->fib_protocol = cfg->fc_protocol;
1097 fi->fib_scope = cfg->fc_scope;
1098 fi->fib_flags = cfg->fc_flags;
1099 fi->fib_priority = cfg->fc_priority;
1100 fi->fib_prefsrc = cfg->fc_prefsrc;
1101 fi->fib_type = cfg->fc_type;
1102 fi->fib_tb_id = cfg->fc_table;
1105 change_nexthops(fi) {
1106 nexthop_nh->nh_parent = fi;
1107 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1108 if (!nexthop_nh->nh_pcpu_rth_output)
1110 } endfor_nexthops(fi)
1112 err = fib_convert_metrics(fi, cfg);
1117 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1118 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1121 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1122 NL_SET_ERR_MSG(extack,
1123 "Nexthop device index does not match RTA_OIF");
1126 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1127 NL_SET_ERR_MSG(extack,
1128 "Nexthop gateway does not match RTA_GATEWAY");
1131 #ifdef CONFIG_IP_ROUTE_CLASSID
1132 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1133 NL_SET_ERR_MSG(extack,
1134 "Nexthop class id does not match RTA_FLOW");
1139 NL_SET_ERR_MSG(extack,
1140 "Multipath support not enabled in kernel");
1144 struct fib_nh *nh = fi->fib_nh;
1146 if (cfg->fc_encap) {
1147 struct lwtunnel_state *lwtstate;
1149 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1150 NL_SET_ERR_MSG(extack,
1151 "LWT encap type not specified");
1154 err = lwtunnel_build_state(cfg->fc_encap_type,
1155 cfg->fc_encap, AF_INET, cfg,
1160 nh->nh_lwtstate = lwtstate_get(lwtstate);
1162 nh->nh_oif = cfg->fc_oif;
1163 nh->nh_gw = cfg->fc_gw;
1164 nh->nh_flags = cfg->fc_flags;
1165 #ifdef CONFIG_IP_ROUTE_CLASSID
1166 nh->nh_tclassid = cfg->fc_flow;
1167 if (nh->nh_tclassid)
1168 fi->fib_net->ipv4.fib_num_tclassid_users++;
1170 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1175 if (fib_props[cfg->fc_type].error) {
1176 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1177 NL_SET_ERR_MSG(extack,
1178 "Gateway, device and multipath can not be specified for this route type");
1183 switch (cfg->fc_type) {
1191 NL_SET_ERR_MSG(extack, "Invalid route type");
1196 if (cfg->fc_scope > RT_SCOPE_HOST) {
1197 NL_SET_ERR_MSG(extack, "Invalid scope");
1201 if (cfg->fc_scope == RT_SCOPE_HOST) {
1202 struct fib_nh *nh = fi->fib_nh;
1204 /* Local address is added. */
1206 NL_SET_ERR_MSG(extack,
1207 "Route with host scope can not have multiple nexthops");
1211 NL_SET_ERR_MSG(extack,
1212 "Route with host scope can not have a gateway");
1215 nh->nh_scope = RT_SCOPE_NOWHERE;
1216 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1223 change_nexthops(fi) {
1224 err = fib_check_nh(cfg, fi, nexthop_nh, extack);
1227 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1229 } endfor_nexthops(fi)
1230 if (linkdown == fi->fib_nhs)
1231 fi->fib_flags |= RTNH_F_LINKDOWN;
1234 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1235 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1239 change_nexthops(fi) {
1240 fib_info_update_nh_saddr(net, nexthop_nh);
1241 fib_add_weight(fi, nexthop_nh);
1242 } endfor_nexthops(fi)
1247 ofi = fib_find_info(fi);
1256 refcount_set(&fi->fib_clntref, 1);
1257 spin_lock_bh(&fib_info_lock);
1258 hlist_add_head(&fi->fib_hash,
1259 &fib_info_hash[fib_info_hashfn(fi)]);
1260 if (fi->fib_prefsrc) {
1261 struct hlist_head *head;
1263 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1264 hlist_add_head(&fi->fib_lhash, head);
1266 change_nexthops(fi) {
1267 struct hlist_head *head;
1270 if (!nexthop_nh->nh_dev)
1272 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1273 head = &fib_info_devhash[hash];
1274 hlist_add_head(&nexthop_nh->nh_hash, head);
1275 } endfor_nexthops(fi)
1276 spin_unlock_bh(&fib_info_lock);
1288 return ERR_PTR(err);
1291 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1292 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1293 struct fib_info *fi, unsigned int flags)
1295 struct nlmsghdr *nlh;
1298 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1302 rtm = nlmsg_data(nlh);
1303 rtm->rtm_family = AF_INET;
1304 rtm->rtm_dst_len = dst_len;
1305 rtm->rtm_src_len = 0;
1308 rtm->rtm_table = tb_id;
1310 rtm->rtm_table = RT_TABLE_COMPAT;
1311 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1312 goto nla_put_failure;
1313 rtm->rtm_type = type;
1314 rtm->rtm_flags = fi->fib_flags;
1315 rtm->rtm_scope = fi->fib_scope;
1316 rtm->rtm_protocol = fi->fib_protocol;
1318 if (rtm->rtm_dst_len &&
1319 nla_put_in_addr(skb, RTA_DST, dst))
1320 goto nla_put_failure;
1321 if (fi->fib_priority &&
1322 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1323 goto nla_put_failure;
1324 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1325 goto nla_put_failure;
1327 if (fi->fib_prefsrc &&
1328 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1329 goto nla_put_failure;
1330 if (fi->fib_nhs == 1) {
1331 struct in_device *in_dev;
1333 if (fi->fib_nh->nh_gw &&
1334 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1335 goto nla_put_failure;
1336 if (fi->fib_nh->nh_oif &&
1337 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1338 goto nla_put_failure;
1339 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1340 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1342 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1343 rtm->rtm_flags |= RTNH_F_DEAD;
1345 #ifdef CONFIG_IP_ROUTE_CLASSID
1346 if (fi->fib_nh[0].nh_tclassid &&
1347 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1348 goto nla_put_failure;
1350 if (fi->fib_nh->nh_lwtstate &&
1351 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1352 goto nla_put_failure;
1354 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1355 if (fi->fib_nhs > 1) {
1356 struct rtnexthop *rtnh;
1359 mp = nla_nest_start(skb, RTA_MULTIPATH);
1361 goto nla_put_failure;
1364 struct in_device *in_dev;
1366 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1368 goto nla_put_failure;
1370 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1371 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1372 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1374 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1375 rtnh->rtnh_flags |= RTNH_F_DEAD;
1377 rtnh->rtnh_hops = nh->nh_weight - 1;
1378 rtnh->rtnh_ifindex = nh->nh_oif;
1381 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1382 goto nla_put_failure;
1383 #ifdef CONFIG_IP_ROUTE_CLASSID
1384 if (nh->nh_tclassid &&
1385 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1386 goto nla_put_failure;
1388 if (nh->nh_lwtstate &&
1389 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1390 goto nla_put_failure;
1392 /* length of rtnetlink header + attributes */
1393 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1394 } endfor_nexthops(fi);
1396 nla_nest_end(skb, mp);
1399 nlmsg_end(skb, nlh);
1403 nlmsg_cancel(skb, nlh);
1409 * - local address disappeared -> we must delete all the entries
1411 * - device went down -> we must shutdown all nexthops going via it.
1413 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1416 unsigned int hash = fib_laddr_hashfn(local);
1417 struct hlist_head *head = &fib_info_laddrhash[hash];
1418 struct net *net = dev_net(dev);
1419 int tb_id = l3mdev_fib_table(dev);
1420 struct fib_info *fi;
1422 if (!fib_info_laddrhash || local == 0)
1425 hlist_for_each_entry(fi, head, fib_lhash) {
1426 if (!net_eq(fi->fib_net, net) ||
1427 fi->fib_tb_id != tb_id)
1429 if (fi->fib_prefsrc == local) {
1430 fi->fib_flags |= RTNH_F_DEAD;
1437 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1438 enum fib_event_type event_type)
1440 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1441 struct fib_nh_notifier_info info = {
1445 switch (event_type) {
1446 case FIB_EVENT_NH_ADD:
1447 if (fib_nh->nh_flags & RTNH_F_DEAD)
1449 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1450 fib_nh->nh_flags & RTNH_F_LINKDOWN)
1452 return call_fib_notifiers(dev_net(fib_nh->nh_dev), event_type,
1454 case FIB_EVENT_NH_DEL:
1455 if ((IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1456 fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1457 (fib_nh->nh_flags & RTNH_F_DEAD))
1458 return call_fib_notifiers(dev_net(fib_nh->nh_dev),
1459 event_type, &info.info);
1467 /* Event force Flags Description
1468 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1469 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1470 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1471 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1473 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1476 int scope = RT_SCOPE_NOWHERE;
1477 struct fib_info *prev_fi = NULL;
1478 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1479 struct hlist_head *head = &fib_info_devhash[hash];
1485 hlist_for_each_entry(nh, head, nh_hash) {
1486 struct fib_info *fi = nh->nh_parent;
1489 BUG_ON(!fi->fib_nhs);
1490 if (nh->nh_dev != dev || fi == prev_fi)
1494 change_nexthops(fi) {
1495 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1497 else if (nexthop_nh->nh_dev == dev &&
1498 nexthop_nh->nh_scope != scope) {
1501 case NETDEV_UNREGISTER:
1502 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1505 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1508 call_fib_nh_notifiers(nexthop_nh,
1512 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1513 if (event == NETDEV_UNREGISTER &&
1514 nexthop_nh->nh_dev == dev) {
1519 } endfor_nexthops(fi)
1520 if (dead == fi->fib_nhs) {
1523 case NETDEV_UNREGISTER:
1524 fi->fib_flags |= RTNH_F_DEAD;
1527 fi->fib_flags |= RTNH_F_LINKDOWN;
1539 /* Must be invoked inside of an RCU protected region. */
1540 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1542 struct fib_info *fi = NULL, *last_resort = NULL;
1543 struct hlist_head *fa_head = res->fa_head;
1544 struct fib_table *tb = res->table;
1545 u8 slen = 32 - res->prefixlen;
1546 int order = -1, last_idx = -1;
1547 struct fib_alias *fa, *fa1 = NULL;
1548 u32 last_prio = res->fi->fib_priority;
1551 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1552 struct fib_info *next_fi = fa->fa_info;
1554 if (fa->fa_slen != slen)
1556 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1558 if (fa->tb_id != tb->tb_id)
1560 if (next_fi->fib_priority > last_prio &&
1561 fa->fa_tos == last_tos) {
1566 if (next_fi->fib_flags & RTNH_F_DEAD)
1568 last_tos = fa->fa_tos;
1569 last_prio = next_fi->fib_priority;
1571 if (next_fi->fib_scope != res->scope ||
1572 fa->fa_type != RTN_UNICAST)
1574 if (!next_fi->fib_nh[0].nh_gw ||
1575 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1578 fib_alias_accessed(fa);
1581 if (next_fi != res->fi)
1584 } else if (!fib_detect_death(fi, order, &last_resort,
1585 &last_idx, fa1->fa_default)) {
1586 fib_result_assign(res, fi);
1587 fa1->fa_default = order;
1594 if (order <= 0 || !fi) {
1596 fa1->fa_default = -1;
1600 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1602 fib_result_assign(res, fi);
1603 fa1->fa_default = order;
1608 fib_result_assign(res, last_resort);
1609 fa1->fa_default = last_idx;
1615 * Dead device goes up. We wake up dead nexthops.
1616 * It takes sense only on multipath routes.
1618 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1620 struct fib_info *prev_fi;
1622 struct hlist_head *head;
1626 if (!(dev->flags & IFF_UP))
1629 if (nh_flags & RTNH_F_DEAD) {
1630 unsigned int flags = dev_get_flags(dev);
1632 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1633 nh_flags |= RTNH_F_LINKDOWN;
1637 hash = fib_devindex_hashfn(dev->ifindex);
1638 head = &fib_info_devhash[hash];
1641 hlist_for_each_entry(nh, head, nh_hash) {
1642 struct fib_info *fi = nh->nh_parent;
1645 BUG_ON(!fi->fib_nhs);
1646 if (nh->nh_dev != dev || fi == prev_fi)
1651 change_nexthops(fi) {
1652 if (!(nexthop_nh->nh_flags & nh_flags)) {
1656 if (!nexthop_nh->nh_dev ||
1657 !(nexthop_nh->nh_dev->flags & IFF_UP))
1659 if (nexthop_nh->nh_dev != dev ||
1660 !__in_dev_get_rtnl(dev))
1663 nexthop_nh->nh_flags &= ~nh_flags;
1664 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1665 } endfor_nexthops(fi)
1668 fi->fib_flags &= ~nh_flags;
1678 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1679 static bool fib_good_nh(const struct fib_nh *nh)
1681 int state = NUD_REACHABLE;
1683 if (nh->nh_scope == RT_SCOPE_LINK) {
1684 struct neighbour *n;
1688 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1689 (__force u32)nh->nh_gw);
1691 state = n->nud_state;
1693 rcu_read_unlock_bh();
1696 return !!(state & NUD_VALID);
1699 void fib_select_multipath(struct fib_result *res, int hash)
1701 struct fib_info *fi = res->fi;
1702 struct net *net = fi->fib_net;
1706 if (hash > atomic_read(&nh->nh_upper_bound))
1709 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1711 res->nh_sel = nhsel;
1715 res->nh_sel = nhsel;
1718 } endfor_nexthops(fi);
1722 void fib_select_path(struct net *net, struct fib_result *res,
1723 struct flowi4 *fl4, const struct sk_buff *skb)
1727 oif_check = (fl4->flowi4_oif == 0 ||
1728 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1730 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1731 if (res->fi->fib_nhs > 1 && oif_check) {
1732 int h = fib_multipath_hash(res->fi, fl4, skb);
1734 fib_select_multipath(res, h);
1738 if (!res->prefixlen &&
1739 res->table->tb_num_default > 1 &&
1740 res->type == RTN_UNICAST && oif_check)
1741 fib_select_default(fl4, res);
1744 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1746 EXPORT_SYMBOL_GPL(fib_select_path);