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 * ROUTE - implementation of the IP router.
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
65 #define pr_fmt(fmt) "IPv4: " fmt
67 #include <linux/module.h>
68 #include <asm/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/types.h>
71 #include <linux/kernel.h>
73 #include <linux/bootmem.h>
74 #include <linux/string.h>
75 #include <linux/socket.h>
76 #include <linux/sockios.h>
77 #include <linux/errno.h>
79 #include <linux/inet.h>
80 #include <linux/netdevice.h>
81 #include <linux/proc_fs.h>
82 #include <linux/init.h>
83 #include <linux/skbuff.h>
84 #include <linux/inetdevice.h>
85 #include <linux/igmp.h>
86 #include <linux/pkt_sched.h>
87 #include <linux/mroute.h>
88 #include <linux/netfilter_ipv4.h>
89 #include <linux/random.h>
90 #include <linux/rcupdate.h>
91 #include <linux/times.h>
92 #include <linux/slab.h>
93 #include <linux/jhash.h>
95 #include <net/dst_metadata.h>
96 #include <net/net_namespace.h>
97 #include <net/protocol.h>
99 #include <net/route.h>
100 #include <net/inetpeer.h>
101 #include <net/sock.h>
102 #include <net/ip_fib.h>
105 #include <net/icmp.h>
106 #include <net/xfrm.h>
107 #include <net/lwtunnel.h>
108 #include <net/netevent.h>
109 #include <net/rtnetlink.h>
111 #include <linux/sysctl.h>
112 #include <linux/kmemleak.h>
114 #include <net/secure_seq.h>
115 #include <net/ip_tunnels.h>
116 #include <net/l3mdev.h>
118 #define RT_FL_TOS(oldflp4) \
119 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
121 #define RT_GC_TIMEOUT (300*HZ)
123 static int ip_rt_max_size;
124 static int ip_rt_redirect_number __read_mostly = 9;
125 static int ip_rt_redirect_load __read_mostly = HZ / 50;
126 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
127 static int ip_rt_error_cost __read_mostly = HZ;
128 static int ip_rt_error_burst __read_mostly = 5 * HZ;
129 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
130 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
131 static int ip_rt_min_advmss __read_mostly = 256;
133 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
136 * Interface to generic destination cache.
139 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
140 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
141 static unsigned int ipv4_mtu(const struct dst_entry *dst);
142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
143 static void ipv4_link_failure(struct sk_buff *skb);
144 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb, u32 mtu);
146 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
147 struct sk_buff *skb);
148 static void ipv4_dst_destroy(struct dst_entry *dst);
150 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
156 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
160 static struct dst_ops ipv4_dst_ops = {
162 .check = ipv4_dst_check,
163 .default_advmss = ipv4_default_advmss,
165 .cow_metrics = ipv4_cow_metrics,
166 .destroy = ipv4_dst_destroy,
167 .negative_advice = ipv4_negative_advice,
168 .link_failure = ipv4_link_failure,
169 .update_pmtu = ip_rt_update_pmtu,
170 .redirect = ip_do_redirect,
171 .local_out = __ip_local_out,
172 .neigh_lookup = ipv4_neigh_lookup,
175 #define ECN_OR_COST(class) TC_PRIO_##class
177 const __u8 ip_tos2prio[16] = {
179 ECN_OR_COST(BESTEFFORT),
181 ECN_OR_COST(BESTEFFORT),
187 ECN_OR_COST(INTERACTIVE),
189 ECN_OR_COST(INTERACTIVE),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK)
195 EXPORT_SYMBOL(ip_tos2prio);
197 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
198 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
200 #ifdef CONFIG_PROC_FS
201 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
205 return SEQ_START_TOKEN;
208 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
214 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
218 static int rt_cache_seq_show(struct seq_file *seq, void *v)
220 if (v == SEQ_START_TOKEN)
221 seq_printf(seq, "%-127s\n",
222 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
223 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
228 static const struct seq_operations rt_cache_seq_ops = {
229 .start = rt_cache_seq_start,
230 .next = rt_cache_seq_next,
231 .stop = rt_cache_seq_stop,
232 .show = rt_cache_seq_show,
235 static int rt_cache_seq_open(struct inode *inode, struct file *file)
237 return seq_open(file, &rt_cache_seq_ops);
240 static const struct file_operations rt_cache_seq_fops = {
241 .owner = THIS_MODULE,
242 .open = rt_cache_seq_open,
245 .release = seq_release,
249 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
254 return SEQ_START_TOKEN;
256 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
257 if (!cpu_possible(cpu))
260 return &per_cpu(rt_cache_stat, cpu);
265 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
269 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
270 if (!cpu_possible(cpu))
273 return &per_cpu(rt_cache_stat, cpu);
280 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
285 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
287 struct rt_cache_stat *st = v;
289 if (v == SEQ_START_TOKEN) {
290 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
294 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
295 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
296 dst_entries_get_slow(&ipv4_dst_ops),
309 0, /* st->gc_total */
310 0, /* st->gc_ignored */
311 0, /* st->gc_goal_miss */
312 0, /* st->gc_dst_overflow */
313 0, /* st->in_hlist_search */
314 0 /* st->out_hlist_search */
319 static const struct seq_operations rt_cpu_seq_ops = {
320 .start = rt_cpu_seq_start,
321 .next = rt_cpu_seq_next,
322 .stop = rt_cpu_seq_stop,
323 .show = rt_cpu_seq_show,
327 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
329 return seq_open(file, &rt_cpu_seq_ops);
332 static const struct file_operations rt_cpu_seq_fops = {
333 .owner = THIS_MODULE,
334 .open = rt_cpu_seq_open,
337 .release = seq_release,
340 #ifdef CONFIG_IP_ROUTE_CLASSID
341 static int rt_acct_proc_show(struct seq_file *m, void *v)
343 struct ip_rt_acct *dst, *src;
346 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
350 for_each_possible_cpu(i) {
351 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
352 for (j = 0; j < 256; j++) {
353 dst[j].o_bytes += src[j].o_bytes;
354 dst[j].o_packets += src[j].o_packets;
355 dst[j].i_bytes += src[j].i_bytes;
356 dst[j].i_packets += src[j].i_packets;
360 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
365 static int rt_acct_proc_open(struct inode *inode, struct file *file)
367 return single_open(file, rt_acct_proc_show, NULL);
370 static const struct file_operations rt_acct_proc_fops = {
371 .owner = THIS_MODULE,
372 .open = rt_acct_proc_open,
375 .release = single_release,
379 static int __net_init ip_rt_do_proc_init(struct net *net)
381 struct proc_dir_entry *pde;
383 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
388 pde = proc_create("rt_cache", S_IRUGO,
389 net->proc_net_stat, &rt_cpu_seq_fops);
393 #ifdef CONFIG_IP_ROUTE_CLASSID
394 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
400 #ifdef CONFIG_IP_ROUTE_CLASSID
402 remove_proc_entry("rt_cache", net->proc_net_stat);
405 remove_proc_entry("rt_cache", net->proc_net);
410 static void __net_exit ip_rt_do_proc_exit(struct net *net)
412 remove_proc_entry("rt_cache", net->proc_net_stat);
413 remove_proc_entry("rt_cache", net->proc_net);
414 #ifdef CONFIG_IP_ROUTE_CLASSID
415 remove_proc_entry("rt_acct", net->proc_net);
419 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
420 .init = ip_rt_do_proc_init,
421 .exit = ip_rt_do_proc_exit,
424 static int __init ip_rt_proc_init(void)
426 return register_pernet_subsys(&ip_rt_proc_ops);
430 static inline int ip_rt_proc_init(void)
434 #endif /* CONFIG_PROC_FS */
436 static inline bool rt_is_expired(const struct rtable *rth)
438 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
441 void rt_cache_flush(struct net *net)
443 rt_genid_bump_ipv4(net);
446 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
450 struct net_device *dev = dst->dev;
451 const __be32 *pkey = daddr;
452 const struct rtable *rt;
455 rt = (const struct rtable *) dst;
457 pkey = (const __be32 *) &rt->rt_gateway;
459 pkey = &ip_hdr(skb)->daddr;
461 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
464 return neigh_create(&arp_tbl, pkey, dev);
467 /* Hash tables of size 2048..262144 depending on RAM size.
468 * Each bucket uses 8 bytes.
470 static u32 ip_idents_mask __read_mostly;
471 static atomic_t *ip_idents __read_mostly;
472 static u32 *ip_tstamps __read_mostly;
474 /* In order to protect privacy, we add a perturbation to identifiers
475 * if one generator is seldom used. This makes hard for an attacker
476 * to infer how many packets were sent between two points in time.
478 u32 ip_idents_reserve(u32 hash, int segs)
480 u32 bucket, old, now = (u32)jiffies;
485 bucket = hash & ip_idents_mask;
486 p_tstamp = ip_tstamps + bucket;
487 p_id = ip_idents + bucket;
488 old = ACCESS_ONCE(*p_tstamp);
490 if (old != now && cmpxchg(p_tstamp, old, now) == old)
491 delta = prandom_u32_max(now - old);
493 /* If UBSAN reports an error there, please make sure your compiler
494 * supports -fno-strict-overflow before reporting it that was a bug
495 * in UBSAN, and it has been fixed in GCC-8.
497 return atomic_add_return(segs + delta, p_id) - segs;
499 EXPORT_SYMBOL(ip_idents_reserve);
501 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
505 /* Note the following code is not safe, but this is okay. */
506 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
507 get_random_bytes(&net->ipv4.ip_id_key,
508 sizeof(net->ipv4.ip_id_key));
510 hash = siphash_3u32((__force u32)iph->daddr,
511 (__force u32)iph->saddr,
513 &net->ipv4.ip_id_key);
514 id = ip_idents_reserve(hash, segs);
517 EXPORT_SYMBOL(__ip_select_ident);
519 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
520 const struct iphdr *iph,
522 u8 prot, u32 mark, int flow_flags)
525 const struct inet_sock *inet = inet_sk(sk);
527 oif = sk->sk_bound_dev_if;
529 tos = RT_CONN_FLAGS(sk);
530 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
532 flowi4_init_output(fl4, oif, mark, tos,
533 RT_SCOPE_UNIVERSE, prot,
535 iph->daddr, iph->saddr, 0, 0);
538 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
539 const struct sock *sk)
541 const struct iphdr *iph = ip_hdr(skb);
542 int oif = skb->dev->ifindex;
543 u8 tos = RT_TOS(iph->tos);
544 u8 prot = iph->protocol;
545 u32 mark = skb->mark;
547 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
550 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
552 const struct inet_sock *inet = inet_sk(sk);
553 const struct ip_options_rcu *inet_opt;
554 __be32 daddr = inet->inet_daddr;
557 inet_opt = rcu_dereference(inet->inet_opt);
558 if (inet_opt && inet_opt->opt.srr)
559 daddr = inet_opt->opt.faddr;
560 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
561 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
562 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
563 inet_sk_flowi_flags(sk),
564 daddr, inet->inet_saddr, 0, 0);
568 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
569 const struct sk_buff *skb)
572 build_skb_flow_key(fl4, skb, sk);
574 build_sk_flow_key(fl4, sk);
577 static inline void rt_free(struct rtable *rt)
579 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
582 static DEFINE_SPINLOCK(fnhe_lock);
584 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
588 rt = rcu_dereference(fnhe->fnhe_rth_input);
590 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
593 rt = rcu_dereference(fnhe->fnhe_rth_output);
595 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
600 static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
602 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
603 struct fib_nh_exception *fnhe, *oldest = NULL;
605 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
606 fnhe = rcu_dereference_protected(*fnhe_p,
607 lockdep_is_held(&fnhe_lock));
611 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
616 fnhe_flush_routes(oldest);
617 *oldest_p = oldest->fnhe_next;
618 kfree_rcu(oldest, rcu);
621 static inline u32 fnhe_hashfun(__be32 daddr)
623 static u32 fnhe_hashrnd __read_mostly;
626 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
627 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
628 return hash_32(hval, FNHE_HASH_SHIFT);
631 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
633 rt->rt_pmtu = fnhe->fnhe_pmtu;
634 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
635 rt->dst.expires = fnhe->fnhe_expires;
638 rt->rt_flags |= RTCF_REDIRECTED;
639 rt->rt_gateway = fnhe->fnhe_gw;
640 rt->rt_uses_gateway = 1;
644 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
645 u32 pmtu, bool lock, unsigned long expires)
647 struct fnhe_hash_bucket *hash;
648 struct fib_nh_exception *fnhe;
654 genid = fnhe_genid(dev_net(nh->nh_dev));
655 hval = fnhe_hashfun(daddr);
657 spin_lock_bh(&fnhe_lock);
659 hash = rcu_dereference(nh->nh_exceptions);
661 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
664 rcu_assign_pointer(nh->nh_exceptions, hash);
670 for (fnhe = rcu_dereference(hash->chain); fnhe;
671 fnhe = rcu_dereference(fnhe->fnhe_next)) {
672 if (fnhe->fnhe_daddr == daddr)
678 if (fnhe->fnhe_genid != genid)
679 fnhe->fnhe_genid = genid;
683 fnhe->fnhe_pmtu = pmtu;
684 fnhe->fnhe_mtu_locked = lock;
686 fnhe->fnhe_expires = max(1UL, expires);
687 /* Update all cached dsts too */
688 rt = rcu_dereference(fnhe->fnhe_rth_input);
690 fill_route_from_fnhe(rt, fnhe);
691 rt = rcu_dereference(fnhe->fnhe_rth_output);
693 fill_route_from_fnhe(rt, fnhe);
695 /* Randomize max depth to avoid some side channels attacks. */
696 int max_depth = FNHE_RECLAIM_DEPTH +
697 prandom_u32_max(FNHE_RECLAIM_DEPTH);
699 while (depth > max_depth) {
700 fnhe_remove_oldest(hash);
704 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
708 fnhe->fnhe_next = hash->chain;
710 fnhe->fnhe_genid = genid;
711 fnhe->fnhe_daddr = daddr;
713 fnhe->fnhe_pmtu = pmtu;
714 fnhe->fnhe_mtu_locked = lock;
715 fnhe->fnhe_expires = expires;
717 rcu_assign_pointer(hash->chain, fnhe);
719 /* Exception created; mark the cached routes for the nexthop
720 * stale, so anyone caching it rechecks if this exception
723 rt = rcu_dereference(nh->nh_rth_input);
725 rt->dst.obsolete = DST_OBSOLETE_KILL;
727 for_each_possible_cpu(i) {
728 struct rtable __rcu **prt;
729 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
730 rt = rcu_dereference(*prt);
732 rt->dst.obsolete = DST_OBSOLETE_KILL;
736 fnhe->fnhe_stamp = jiffies;
739 spin_unlock_bh(&fnhe_lock);
742 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
745 __be32 new_gw = icmp_hdr(skb)->un.gateway;
746 __be32 old_gw = ip_hdr(skb)->saddr;
747 struct net_device *dev = skb->dev;
748 struct in_device *in_dev;
749 struct fib_result res;
753 switch (icmp_hdr(skb)->code & 7) {
755 case ICMP_REDIR_NETTOS:
756 case ICMP_REDIR_HOST:
757 case ICMP_REDIR_HOSTTOS:
764 if (rt->rt_gateway != old_gw)
767 in_dev = __in_dev_get_rcu(dev);
772 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
773 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
774 ipv4_is_zeronet(new_gw))
775 goto reject_redirect;
777 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
778 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
779 goto reject_redirect;
780 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
781 goto reject_redirect;
783 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
784 goto reject_redirect;
787 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
789 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
791 if (!(n->nud_state & NUD_VALID)) {
792 neigh_event_send(n, NULL);
794 if (fib_lookup(net, fl4, &res, 0) == 0) {
795 struct fib_nh *nh = &FIB_RES_NH(res);
797 update_or_create_fnhe(nh, fl4->daddr, new_gw,
799 jiffies + ip_rt_gc_timeout);
802 rt->dst.obsolete = DST_OBSOLETE_KILL;
803 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
810 #ifdef CONFIG_IP_ROUTE_VERBOSE
811 if (IN_DEV_LOG_MARTIANS(in_dev)) {
812 const struct iphdr *iph = (const struct iphdr *) skb->data;
813 __be32 daddr = iph->daddr;
814 __be32 saddr = iph->saddr;
816 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
817 " Advised path = %pI4 -> %pI4\n",
818 &old_gw, dev->name, &new_gw,
825 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
829 const struct iphdr *iph = (const struct iphdr *) skb->data;
830 int oif = skb->dev->ifindex;
831 u8 tos = RT_TOS(iph->tos);
832 u8 prot = iph->protocol;
833 u32 mark = skb->mark;
835 rt = (struct rtable *) dst;
837 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
838 __ip_do_redirect(rt, skb, &fl4, true);
841 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
843 struct rtable *rt = (struct rtable *)dst;
844 struct dst_entry *ret = dst;
847 if (dst->obsolete > 0) {
850 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
861 * 1. The first ip_rt_redirect_number redirects are sent
862 * with exponential backoff, then we stop sending them at all,
863 * assuming that the host ignores our redirects.
864 * 2. If we did not see packets requiring redirects
865 * during ip_rt_redirect_silence, we assume that the host
866 * forgot redirected route and start to send redirects again.
868 * This algorithm is much cheaper and more intelligent than dumb load limiting
871 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
872 * and "frag. need" (breaks PMTU discovery) in icmp.c.
875 void ip_rt_send_redirect(struct sk_buff *skb)
877 struct rtable *rt = skb_rtable(skb);
878 struct in_device *in_dev;
879 struct inet_peer *peer;
885 in_dev = __in_dev_get_rcu(rt->dst.dev);
886 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
890 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
891 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
894 net = dev_net(rt->dst.dev);
895 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
897 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
898 rt_nexthop(rt, ip_hdr(skb)->daddr));
902 /* No redirected packets during ip_rt_redirect_silence;
903 * reset the algorithm.
905 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
906 peer->rate_tokens = 0;
907 peer->n_redirects = 0;
910 /* Too many ignored redirects; do not send anything
911 * set dst.rate_last to the last seen redirected packet.
913 if (peer->n_redirects >= ip_rt_redirect_number) {
914 peer->rate_last = jiffies;
918 /* Check for load limit; set rate_last to the latest sent
921 if (peer->n_redirects == 0 ||
924 (ip_rt_redirect_load << peer->n_redirects)))) {
925 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
927 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
928 peer->rate_last = jiffies;
930 #ifdef CONFIG_IP_ROUTE_VERBOSE
932 peer->n_redirects == ip_rt_redirect_number)
933 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
934 &ip_hdr(skb)->saddr, inet_iif(skb),
935 &ip_hdr(skb)->daddr, &gw);
942 static int ip_error(struct sk_buff *skb)
944 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
945 struct rtable *rt = skb_rtable(skb);
946 struct inet_peer *peer;
952 /* IP on this device is disabled. */
956 net = dev_net(rt->dst.dev);
957 if (!IN_DEV_FORWARD(in_dev)) {
958 switch (rt->dst.error) {
960 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
964 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
970 switch (rt->dst.error) {
975 code = ICMP_HOST_UNREACH;
978 code = ICMP_NET_UNREACH;
979 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
982 code = ICMP_PKT_FILTERED;
986 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
987 l3mdev_master_ifindex(skb->dev), 1);
992 peer->rate_tokens += now - peer->rate_last;
993 if (peer->rate_tokens > ip_rt_error_burst)
994 peer->rate_tokens = ip_rt_error_burst;
995 peer->rate_last = now;
996 if (peer->rate_tokens >= ip_rt_error_cost)
997 peer->rate_tokens -= ip_rt_error_cost;
1003 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1005 out: kfree_skb(skb);
1009 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1011 struct dst_entry *dst = &rt->dst;
1012 u32 old_mtu = ipv4_mtu(dst);
1013 struct fib_result res;
1016 if (ip_mtu_locked(dst))
1022 if (mtu < ip_rt_min_pmtu) {
1024 mtu = min(old_mtu, ip_rt_min_pmtu);
1027 if (rt->rt_pmtu == mtu && !lock &&
1028 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1032 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1033 struct fib_nh *nh = &FIB_RES_NH(res);
1035 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock,
1036 jiffies + ip_rt_mtu_expires);
1041 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1042 struct sk_buff *skb, u32 mtu)
1044 struct rtable *rt = (struct rtable *) dst;
1047 ip_rt_build_flow_key(&fl4, sk, skb);
1048 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1052 int oif, u32 mark, u8 protocol, int flow_flags)
1054 const struct iphdr *iph = (const struct iphdr *) skb->data;
1059 mark = IP4_REPLY_MARK(net, skb->mark);
1061 __build_flow_key(&fl4, NULL, iph, oif,
1062 RT_TOS(iph->tos), protocol, mark, flow_flags);
1063 rt = __ip_route_output_key(net, &fl4);
1065 __ip_rt_update_pmtu(rt, &fl4, mtu);
1069 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1071 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1073 const struct iphdr *iph = (const struct iphdr *) skb->data;
1077 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1079 if (!fl4.flowi4_mark)
1080 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1082 rt = __ip_route_output_key(sock_net(sk), &fl4);
1084 __ip_rt_update_pmtu(rt, &fl4, mtu);
1089 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1091 const struct iphdr *iph = (const struct iphdr *) skb->data;
1094 struct dst_entry *odst = NULL;
1099 if (!ip_sk_accept_pmtu(sk))
1102 odst = sk_dst_get(sk);
1104 if (sock_owned_by_user(sk) || !odst) {
1105 __ipv4_sk_update_pmtu(skb, sk, mtu);
1109 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1111 rt = (struct rtable *)odst;
1112 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1113 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1120 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1122 if (!dst_check(&rt->dst, 0)) {
1124 dst_release(&rt->dst);
1126 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1134 sk_dst_set(sk, &rt->dst);
1140 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1142 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1143 int oif, u32 mark, u8 protocol, int flow_flags)
1145 const struct iphdr *iph = (const struct iphdr *) skb->data;
1149 __build_flow_key(&fl4, NULL, iph, oif,
1150 RT_TOS(iph->tos), protocol, mark, flow_flags);
1151 rt = __ip_route_output_key(net, &fl4);
1153 __ip_do_redirect(rt, skb, &fl4, false);
1157 EXPORT_SYMBOL_GPL(ipv4_redirect);
1159 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1161 const struct iphdr *iph = (const struct iphdr *) skb->data;
1165 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1166 rt = __ip_route_output_key(sock_net(sk), &fl4);
1168 __ip_do_redirect(rt, skb, &fl4, false);
1172 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1174 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1176 struct rtable *rt = (struct rtable *) dst;
1178 /* All IPV4 dsts are created with ->obsolete set to the value
1179 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1180 * into this function always.
1182 * When a PMTU/redirect information update invalidates a route,
1183 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1184 * DST_OBSOLETE_DEAD by dst_free().
1186 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1191 static void ipv4_send_dest_unreach(struct sk_buff *skb)
1193 struct ip_options opt;
1196 /* Recompile ip options since IPCB may not be valid anymore.
1197 * Also check we have a reasonable ipv4 header.
1199 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1200 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1203 memset(&opt, 0, sizeof(opt));
1204 if (ip_hdr(skb)->ihl > 5) {
1205 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1207 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1210 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1216 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1219 static void ipv4_link_failure(struct sk_buff *skb)
1223 ipv4_send_dest_unreach(skb);
1225 rt = skb_rtable(skb);
1227 dst_set_expires(&rt->dst, 0);
1230 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1232 pr_debug("%s: %pI4 -> %pI4, %s\n",
1233 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1234 skb->dev ? skb->dev->name : "?");
1241 We do not cache source address of outgoing interface,
1242 because it is used only by IP RR, TS and SRR options,
1243 so that it out of fast path.
1245 BTW remember: "addr" is allowed to be not aligned
1249 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1253 if (rt_is_output_route(rt))
1254 src = ip_hdr(skb)->saddr;
1256 struct fib_result res;
1262 memset(&fl4, 0, sizeof(fl4));
1263 fl4.daddr = iph->daddr;
1264 fl4.saddr = iph->saddr;
1265 fl4.flowi4_tos = RT_TOS(iph->tos);
1266 fl4.flowi4_oif = rt->dst.dev->ifindex;
1267 fl4.flowi4_iif = skb->dev->ifindex;
1268 fl4.flowi4_mark = skb->mark;
1271 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1272 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1274 src = inet_select_addr(rt->dst.dev,
1275 rt_nexthop(rt, iph->daddr),
1279 memcpy(addr, &src, 4);
1282 #ifdef CONFIG_IP_ROUTE_CLASSID
1283 static void set_class_tag(struct rtable *rt, u32 tag)
1285 if (!(rt->dst.tclassid & 0xFFFF))
1286 rt->dst.tclassid |= tag & 0xFFFF;
1287 if (!(rt->dst.tclassid & 0xFFFF0000))
1288 rt->dst.tclassid |= tag & 0xFFFF0000;
1292 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1294 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1297 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1299 if (advmss > 65535 - 40)
1300 advmss = 65535 - 40;
1305 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1307 const struct rtable *rt = (const struct rtable *) dst;
1308 unsigned int mtu = rt->rt_pmtu;
1310 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1311 mtu = dst_metric_raw(dst, RTAX_MTU);
1316 mtu = READ_ONCE(dst->dev->mtu);
1318 if (unlikely(ip_mtu_locked(dst))) {
1319 if (rt->rt_uses_gateway && mtu > 576)
1323 return min_t(unsigned int, mtu, IP_MAX_MTU);
1326 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1328 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1329 struct fib_nh_exception *fnhe;
1335 hval = fnhe_hashfun(daddr);
1337 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1338 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1339 if (fnhe->fnhe_daddr == daddr)
1345 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1350 spin_lock_bh(&fnhe_lock);
1352 if (daddr == fnhe->fnhe_daddr) {
1353 struct rtable __rcu **porig;
1354 struct rtable *orig;
1355 int genid = fnhe_genid(dev_net(rt->dst.dev));
1357 if (rt_is_input_route(rt))
1358 porig = &fnhe->fnhe_rth_input;
1360 porig = &fnhe->fnhe_rth_output;
1361 orig = rcu_dereference(*porig);
1363 if (fnhe->fnhe_genid != genid) {
1364 fnhe->fnhe_genid = genid;
1366 fnhe->fnhe_pmtu = 0;
1367 fnhe->fnhe_expires = 0;
1368 fnhe_flush_routes(fnhe);
1371 fill_route_from_fnhe(rt, fnhe);
1372 if (!rt->rt_gateway)
1373 rt->rt_gateway = daddr;
1375 if (!(rt->dst.flags & DST_NOCACHE)) {
1376 rcu_assign_pointer(*porig, rt);
1382 fnhe->fnhe_stamp = jiffies;
1384 spin_unlock_bh(&fnhe_lock);
1389 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1391 struct rtable *orig, *prev, **p;
1394 if (rt_is_input_route(rt)) {
1395 p = (struct rtable **)&nh->nh_rth_input;
1397 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1401 prev = cmpxchg(p, orig, rt);
1411 struct uncached_list {
1413 struct list_head head;
1416 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1418 static void rt_add_uncached_list(struct rtable *rt)
1420 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1422 rt->rt_uncached_list = ul;
1424 spin_lock_bh(&ul->lock);
1425 list_add_tail(&rt->rt_uncached, &ul->head);
1426 spin_unlock_bh(&ul->lock);
1429 static void ipv4_dst_destroy(struct dst_entry *dst)
1431 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1432 struct rtable *rt = (struct rtable *) dst;
1434 if (p != &dst_default_metrics && atomic_dec_and_test(&p->refcnt))
1437 if (!list_empty(&rt->rt_uncached)) {
1438 struct uncached_list *ul = rt->rt_uncached_list;
1440 spin_lock_bh(&ul->lock);
1441 list_del(&rt->rt_uncached);
1442 spin_unlock_bh(&ul->lock);
1446 void rt_flush_dev(struct net_device *dev)
1448 struct net *net = dev_net(dev);
1452 for_each_possible_cpu(cpu) {
1453 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1455 spin_lock_bh(&ul->lock);
1456 list_for_each_entry(rt, &ul->head, rt_uncached) {
1457 if (rt->dst.dev != dev)
1459 rt->dst.dev = net->loopback_dev;
1460 dev_hold(rt->dst.dev);
1463 spin_unlock_bh(&ul->lock);
1467 static bool rt_cache_valid(const struct rtable *rt)
1470 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1474 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1475 const struct fib_result *res,
1476 struct fib_nh_exception *fnhe,
1477 struct fib_info *fi, u16 type, u32 itag)
1479 bool cached = false;
1482 struct fib_nh *nh = &FIB_RES_NH(*res);
1484 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1485 rt->rt_gateway = nh->nh_gw;
1486 rt->rt_uses_gateway = 1;
1488 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1489 if (fi->fib_metrics != &dst_default_metrics) {
1490 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1491 atomic_inc(&fi->fib_metrics->refcnt);
1493 #ifdef CONFIG_IP_ROUTE_CLASSID
1494 rt->dst.tclassid = nh->nh_tclassid;
1496 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1498 cached = rt_bind_exception(rt, fnhe, daddr);
1499 else if (!(rt->dst.flags & DST_NOCACHE))
1500 cached = rt_cache_route(nh, rt);
1501 if (unlikely(!cached)) {
1502 /* Routes we intend to cache in nexthop exception or
1503 * FIB nexthop have the DST_NOCACHE bit clear.
1504 * However, if we are unsuccessful at storing this
1505 * route into the cache we really need to set it.
1507 rt->dst.flags |= DST_NOCACHE;
1508 if (!rt->rt_gateway)
1509 rt->rt_gateway = daddr;
1510 rt_add_uncached_list(rt);
1513 rt_add_uncached_list(rt);
1515 #ifdef CONFIG_IP_ROUTE_CLASSID
1516 #ifdef CONFIG_IP_MULTIPLE_TABLES
1517 set_class_tag(rt, res->tclassid);
1519 set_class_tag(rt, itag);
1523 struct rtable *rt_dst_alloc(struct net_device *dev,
1524 unsigned int flags, u16 type,
1525 bool nopolicy, bool noxfrm, bool will_cache)
1529 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1530 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1531 (nopolicy ? DST_NOPOLICY : 0) |
1532 (noxfrm ? DST_NOXFRM : 0));
1535 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1536 rt->rt_flags = flags;
1538 rt->rt_is_input = 0;
1541 rt->rt_mtu_locked = 0;
1543 rt->rt_uses_gateway = 0;
1544 rt->rt_table_id = 0;
1545 INIT_LIST_HEAD(&rt->rt_uncached);
1547 rt->dst.output = ip_output;
1548 if (flags & RTCF_LOCAL)
1549 rt->dst.input = ip_local_deliver;
1554 EXPORT_SYMBOL(rt_dst_alloc);
1556 /* called in rcu_read_lock() section */
1557 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1558 u8 tos, struct net_device *dev, int our)
1561 struct in_device *in_dev = __in_dev_get_rcu(dev);
1562 unsigned int flags = RTCF_MULTICAST;
1566 /* Primary sanity checks. */
1571 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1572 skb->protocol != htons(ETH_P_IP))
1575 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1578 if (ipv4_is_zeronet(saddr)) {
1579 if (!ipv4_is_local_multicast(daddr))
1582 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1588 flags |= RTCF_LOCAL;
1590 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1591 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1595 #ifdef CONFIG_IP_ROUTE_CLASSID
1596 rth->dst.tclassid = itag;
1598 rth->dst.output = ip_rt_bug;
1599 rth->rt_is_input= 1;
1601 #ifdef CONFIG_IP_MROUTE
1602 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1603 rth->dst.input = ip_mr_input;
1605 RT_CACHE_STAT_INC(in_slow_mc);
1607 skb_dst_set(skb, &rth->dst);
1619 static void ip_handle_martian_source(struct net_device *dev,
1620 struct in_device *in_dev,
1621 struct sk_buff *skb,
1625 RT_CACHE_STAT_INC(in_martian_src);
1626 #ifdef CONFIG_IP_ROUTE_VERBOSE
1627 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1629 * RFC1812 recommendation, if source is martian,
1630 * the only hint is MAC header.
1632 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1633 &daddr, &saddr, dev->name);
1634 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1635 print_hex_dump(KERN_WARNING, "ll header: ",
1636 DUMP_PREFIX_OFFSET, 16, 1,
1637 skb_mac_header(skb),
1638 dev->hard_header_len, true);
1644 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1646 struct fnhe_hash_bucket *hash;
1647 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1648 u32 hval = fnhe_hashfun(daddr);
1650 spin_lock_bh(&fnhe_lock);
1652 hash = rcu_dereference_protected(nh->nh_exceptions,
1653 lockdep_is_held(&fnhe_lock));
1656 fnhe_p = &hash->chain;
1657 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1659 if (fnhe->fnhe_daddr == daddr) {
1660 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1661 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1662 /* set fnhe_daddr to 0 to ensure it won't bind with
1663 * new dsts in rt_bind_exception().
1665 fnhe->fnhe_daddr = 0;
1666 fnhe_flush_routes(fnhe);
1667 kfree_rcu(fnhe, rcu);
1670 fnhe_p = &fnhe->fnhe_next;
1671 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1672 lockdep_is_held(&fnhe_lock));
1675 spin_unlock_bh(&fnhe_lock);
1678 /* called in rcu_read_lock() section */
1679 static int __mkroute_input(struct sk_buff *skb,
1680 const struct fib_result *res,
1681 struct in_device *in_dev,
1682 __be32 daddr, __be32 saddr, u32 tos)
1684 struct fib_nh_exception *fnhe;
1687 struct in_device *out_dev;
1691 /* get a working reference to the output device */
1692 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1694 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1698 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1699 in_dev->dev, in_dev, &itag);
1701 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1707 do_cache = res->fi && !itag;
1708 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1709 skb->protocol == htons(ETH_P_IP) &&
1710 (IN_DEV_SHARED_MEDIA(out_dev) ||
1711 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1712 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1714 if (skb->protocol != htons(ETH_P_IP)) {
1715 /* Not IP (i.e. ARP). Do not create route, if it is
1716 * invalid for proxy arp. DNAT routes are always valid.
1718 * Proxy arp feature have been extended to allow, ARP
1719 * replies back to the same interface, to support
1720 * Private VLAN switch technologies. See arp.c.
1722 if (out_dev == in_dev &&
1723 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1729 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1732 rth = rcu_dereference(fnhe->fnhe_rth_input);
1733 if (rth && rth->dst.expires &&
1734 time_after(jiffies, rth->dst.expires)) {
1735 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1742 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1745 if (rt_cache_valid(rth)) {
1746 skb_dst_set_noref(skb, &rth->dst);
1751 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1752 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1753 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1759 rth->rt_is_input = 1;
1761 rth->rt_table_id = res->table->tb_id;
1762 RT_CACHE_STAT_INC(in_slow_tot);
1764 rth->dst.input = ip_forward;
1766 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1767 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1768 rth->dst.lwtstate->orig_output = rth->dst.output;
1769 rth->dst.output = lwtunnel_output;
1771 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1772 rth->dst.lwtstate->orig_input = rth->dst.input;
1773 rth->dst.input = lwtunnel_input;
1775 skb_dst_set(skb, &rth->dst);
1782 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1784 /* To make ICMP packets follow the right flow, the multipath hash is
1785 * calculated from the inner IP addresses in reverse order.
1787 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1789 const struct iphdr *outer_iph = ip_hdr(skb);
1790 struct icmphdr _icmph;
1791 const struct icmphdr *icmph;
1792 struct iphdr _inner_iph;
1793 const struct iphdr *inner_iph;
1795 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1798 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1803 if (icmph->type != ICMP_DEST_UNREACH &&
1804 icmph->type != ICMP_REDIRECT &&
1805 icmph->type != ICMP_TIME_EXCEEDED &&
1806 icmph->type != ICMP_PARAMETERPROB) {
1810 inner_iph = skb_header_pointer(skb,
1811 outer_iph->ihl * 4 + sizeof(_icmph),
1812 sizeof(_inner_iph), &_inner_iph);
1816 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1819 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1822 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1824 static int ip_mkroute_input(struct sk_buff *skb,
1825 struct fib_result *res,
1826 const struct flowi4 *fl4,
1827 struct in_device *in_dev,
1828 __be32 daddr, __be32 saddr, u32 tos)
1830 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1831 if (res->fi && res->fi->fib_nhs > 1) {
1834 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1835 h = ip_multipath_icmp_hash(skb);
1837 h = fib_multipath_hash(saddr, daddr);
1838 fib_select_multipath(res, h);
1842 /* create a routing cache entry */
1843 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1847 * NOTE. We drop all the packets that has local source
1848 * addresses, because every properly looped back packet
1849 * must have correct destination already attached by output routine.
1851 * Such approach solves two big problems:
1852 * 1. Not simplex devices are handled properly.
1853 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1854 * called with rcu_read_lock()
1857 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1858 u8 tos, struct net_device *dev)
1860 struct fib_result res;
1861 struct in_device *in_dev = __in_dev_get_rcu(dev);
1862 struct ip_tunnel_info *tun_info;
1864 unsigned int flags = 0;
1868 struct net *net = dev_net(dev);
1871 /* IP on this device is disabled. */
1876 /* Check for the most weird martians, which can be not detected
1880 tun_info = skb_tunnel_info(skb);
1881 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1882 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1884 fl4.flowi4_tun_key.tun_id = 0;
1887 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1888 goto martian_source;
1892 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1895 /* Accept zero addresses only to limited broadcast;
1896 * I even do not know to fix it or not. Waiting for complains :-)
1898 if (ipv4_is_zeronet(saddr))
1899 goto martian_source;
1901 if (ipv4_is_zeronet(daddr))
1902 goto martian_destination;
1904 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1905 * and call it once if daddr or/and saddr are loopback addresses
1907 if (ipv4_is_loopback(daddr)) {
1908 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1909 goto martian_destination;
1910 } else if (ipv4_is_loopback(saddr)) {
1911 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1912 goto martian_source;
1916 * Now we are ready to route packet.
1919 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev);
1920 fl4.flowi4_mark = skb->mark;
1921 fl4.flowi4_tos = tos;
1922 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1923 fl4.flowi4_flags = 0;
1926 err = fib_lookup(net, &fl4, &res, 0);
1928 if (!IN_DEV_FORWARD(in_dev))
1929 err = -EHOSTUNREACH;
1933 if (res.type == RTN_BROADCAST)
1936 if (res.type == RTN_LOCAL) {
1937 err = fib_validate_source(skb, saddr, daddr, tos,
1938 0, dev, in_dev, &itag);
1940 goto martian_source;
1944 if (!IN_DEV_FORWARD(in_dev)) {
1945 err = -EHOSTUNREACH;
1948 if (res.type != RTN_UNICAST)
1949 goto martian_destination;
1951 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1955 if (skb->protocol != htons(ETH_P_IP))
1958 if (!ipv4_is_zeronet(saddr)) {
1959 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1962 goto martian_source;
1964 flags |= RTCF_BROADCAST;
1965 res.type = RTN_BROADCAST;
1966 RT_CACHE_STAT_INC(in_brd);
1972 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1973 if (rt_cache_valid(rth)) {
1974 skb_dst_set_noref(skb, &rth->dst);
1982 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
1983 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1987 rth->dst.output= ip_rt_bug;
1988 #ifdef CONFIG_IP_ROUTE_CLASSID
1989 rth->dst.tclassid = itag;
1991 rth->rt_is_input = 1;
1993 rth->rt_table_id = res.table->tb_id;
1995 RT_CACHE_STAT_INC(in_slow_tot);
1996 if (res.type == RTN_UNREACHABLE) {
1997 rth->dst.input= ip_error;
1998 rth->dst.error= -err;
1999 rth->rt_flags &= ~RTCF_LOCAL;
2002 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
2003 rth->dst.flags |= DST_NOCACHE;
2004 rt_add_uncached_list(rth);
2007 skb_dst_set(skb, &rth->dst);
2012 RT_CACHE_STAT_INC(in_no_route);
2013 res.type = RTN_UNREACHABLE;
2019 * Do not cache martian addresses: they should be logged (RFC1812)
2021 martian_destination:
2022 RT_CACHE_STAT_INC(in_martian_dst);
2023 #ifdef CONFIG_IP_ROUTE_VERBOSE
2024 if (IN_DEV_LOG_MARTIANS(in_dev))
2025 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2026 &daddr, &saddr, dev->name);
2038 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2042 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2043 u8 tos, struct net_device *dev)
2047 tos &= IPTOS_RT_MASK;
2050 /* Multicast recognition logic is moved from route cache to here.
2051 The problem was that too many Ethernet cards have broken/missing
2052 hardware multicast filters :-( As result the host on multicasting
2053 network acquires a lot of useless route cache entries, sort of
2054 SDR messages from all the world. Now we try to get rid of them.
2055 Really, provided software IP multicast filter is organized
2056 reasonably (at least, hashed), it does not result in a slowdown
2057 comparing with route cache reject entries.
2058 Note, that multicast routers are not affected, because
2059 route cache entry is created eventually.
2061 if (ipv4_is_multicast(daddr)) {
2062 struct in_device *in_dev = __in_dev_get_rcu(dev);
2065 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2066 ip_hdr(skb)->protocol);
2068 #ifdef CONFIG_IP_MROUTE
2070 (!ipv4_is_local_multicast(daddr) &&
2071 IN_DEV_MFORWARD(in_dev))
2074 int res = ip_route_input_mc(skb, daddr, saddr,
2083 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2087 EXPORT_SYMBOL(ip_route_input_noref);
2089 /* called with rcu_read_lock() */
2090 static struct rtable *__mkroute_output(const struct fib_result *res,
2091 const struct flowi4 *fl4, int orig_oif,
2092 struct net_device *dev_out,
2095 struct fib_info *fi = res->fi;
2096 struct fib_nh_exception *fnhe;
2097 struct in_device *in_dev;
2098 u16 type = res->type;
2102 in_dev = __in_dev_get_rcu(dev_out);
2104 return ERR_PTR(-EINVAL);
2106 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2107 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2108 return ERR_PTR(-EINVAL);
2110 if (ipv4_is_lbcast(fl4->daddr))
2111 type = RTN_BROADCAST;
2112 else if (ipv4_is_multicast(fl4->daddr))
2113 type = RTN_MULTICAST;
2114 else if (ipv4_is_zeronet(fl4->daddr))
2115 return ERR_PTR(-EINVAL);
2117 if (dev_out->flags & IFF_LOOPBACK)
2118 flags |= RTCF_LOCAL;
2121 if (type == RTN_BROADCAST) {
2122 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2124 } else if (type == RTN_MULTICAST) {
2125 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2126 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2128 flags &= ~RTCF_LOCAL;
2131 /* If multicast route do not exist use
2132 * default one, but do not gateway in this case.
2135 if (fi && res->prefixlen < 4)
2137 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2138 (orig_oif != dev_out->ifindex)) {
2139 /* For local routes that require a particular output interface
2140 * we do not want to cache the result. Caching the result
2141 * causes incorrect behaviour when there are multiple source
2142 * addresses on the interface, the end result being that if the
2143 * intended recipient is waiting on that interface for the
2144 * packet he won't receive it because it will be delivered on
2145 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2146 * be set to the loopback interface as well.
2152 do_cache &= fi != NULL;
2154 struct rtable __rcu **prth;
2155 struct fib_nh *nh = &FIB_RES_NH(*res);
2157 fnhe = find_exception(nh, fl4->daddr);
2159 prth = &fnhe->fnhe_rth_output;
2160 rth = rcu_dereference(*prth);
2161 if (rth && rth->dst.expires &&
2162 time_after(jiffies, rth->dst.expires)) {
2163 ip_del_fnhe(nh, fl4->daddr);
2170 if (unlikely(fl4->flowi4_flags &
2171 FLOWI_FLAG_KNOWN_NH &&
2173 nh->nh_scope == RT_SCOPE_LINK))) {
2177 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2178 rth = rcu_dereference(*prth);
2181 if (rt_cache_valid(rth)) {
2182 dst_hold(&rth->dst);
2188 rth = rt_dst_alloc(dev_out, flags, type,
2189 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2190 IN_DEV_CONF_GET(in_dev, NOXFRM),
2193 return ERR_PTR(-ENOBUFS);
2195 rth->rt_iif = orig_oif ? : 0;
2197 rth->rt_table_id = res->table->tb_id;
2199 RT_CACHE_STAT_INC(out_slow_tot);
2201 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2202 if (flags & RTCF_LOCAL &&
2203 !(dev_out->flags & IFF_LOOPBACK)) {
2204 rth->dst.output = ip_mc_output;
2205 RT_CACHE_STAT_INC(out_slow_mc);
2207 #ifdef CONFIG_IP_MROUTE
2208 if (type == RTN_MULTICAST) {
2209 if (IN_DEV_MFORWARD(in_dev) &&
2210 !ipv4_is_local_multicast(fl4->daddr)) {
2211 rth->dst.input = ip_mr_input;
2212 rth->dst.output = ip_mc_output;
2218 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2219 if (lwtunnel_output_redirect(rth->dst.lwtstate))
2220 rth->dst.output = lwtunnel_output;
2226 * Major route resolver routine.
2229 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2232 struct net_device *dev_out = NULL;
2233 __u8 tos = RT_FL_TOS(fl4);
2234 unsigned int flags = 0;
2235 struct fib_result res;
2244 orig_oif = fl4->flowi4_oif;
2246 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2247 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2248 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2249 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2253 if (ipv4_is_multicast(fl4->saddr) ||
2254 ipv4_is_lbcast(fl4->saddr) ||
2255 ipv4_is_zeronet(fl4->saddr)) {
2256 rth = ERR_PTR(-EINVAL);
2260 rth = ERR_PTR(-ENETUNREACH);
2262 /* I removed check for oif == dev_out->oif here.
2263 It was wrong for two reasons:
2264 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2265 is assigned to multiple interfaces.
2266 2. Moreover, we are allowed to send packets with saddr
2267 of another iface. --ANK
2270 if (fl4->flowi4_oif == 0 &&
2271 (ipv4_is_multicast(fl4->daddr) ||
2272 ipv4_is_lbcast(fl4->daddr))) {
2273 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2274 dev_out = __ip_dev_find(net, fl4->saddr, false);
2278 /* Special hack: user can direct multicasts
2279 and limited broadcast via necessary interface
2280 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2281 This hack is not just for fun, it allows
2282 vic,vat and friends to work.
2283 They bind socket to loopback, set ttl to zero
2284 and expect that it will work.
2285 From the viewpoint of routing cache they are broken,
2286 because we are not allowed to build multicast path
2287 with loopback source addr (look, routing cache
2288 cannot know, that ttl is zero, so that packet
2289 will not leave this host and route is valid).
2290 Luckily, this hack is good workaround.
2293 fl4->flowi4_oif = dev_out->ifindex;
2297 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2298 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2299 if (!__ip_dev_find(net, fl4->saddr, false))
2305 if (fl4->flowi4_oif) {
2306 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2307 rth = ERR_PTR(-ENODEV);
2311 /* RACE: Check return value of inet_select_addr instead. */
2312 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2313 rth = ERR_PTR(-ENETUNREACH);
2316 if (ipv4_is_local_multicast(fl4->daddr) ||
2317 ipv4_is_lbcast(fl4->daddr) ||
2318 fl4->flowi4_proto == IPPROTO_IGMP) {
2320 fl4->saddr = inet_select_addr(dev_out, 0,
2325 if (ipv4_is_multicast(fl4->daddr))
2326 fl4->saddr = inet_select_addr(dev_out, 0,
2328 else if (!fl4->daddr)
2329 fl4->saddr = inet_select_addr(dev_out, 0,
2333 rth = l3mdev_get_rtable(dev_out, fl4);
2339 fl4->daddr = fl4->saddr;
2341 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2342 dev_out = net->loopback_dev;
2343 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2344 res.type = RTN_LOCAL;
2345 flags |= RTCF_LOCAL;
2349 err = fib_lookup(net, fl4, &res, 0);
2353 if (fl4->flowi4_oif &&
2354 !netif_index_is_l3_master(net, fl4->flowi4_oif)) {
2355 /* Apparently, routing tables are wrong. Assume,
2356 that the destination is on link.
2359 Because we are allowed to send to iface
2360 even if it has NO routes and NO assigned
2361 addresses. When oif is specified, routing
2362 tables are looked up with only one purpose:
2363 to catch if destination is gatewayed, rather than
2364 direct. Moreover, if MSG_DONTROUTE is set,
2365 we send packet, ignoring both routing tables
2366 and ifaddr state. --ANK
2369 We could make it even if oif is unknown,
2370 likely IPv6, but we do not.
2373 if (fl4->saddr == 0)
2374 fl4->saddr = inet_select_addr(dev_out, 0,
2376 res.type = RTN_UNICAST;
2383 if (res.type == RTN_LOCAL) {
2385 if (res.fi->fib_prefsrc)
2386 fl4->saddr = res.fi->fib_prefsrc;
2388 fl4->saddr = fl4->daddr;
2390 dev_out = net->loopback_dev;
2391 fl4->flowi4_oif = dev_out->ifindex;
2392 flags |= RTCF_LOCAL;
2396 fib_select_path(net, &res, fl4, mp_hash);
2398 dev_out = FIB_RES_DEV(res);
2399 fl4->flowi4_oif = dev_out->ifindex;
2403 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2409 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2411 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2416 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2418 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2420 return mtu ? : dst->dev->mtu;
2423 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2424 struct sk_buff *skb, u32 mtu)
2428 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2429 struct sk_buff *skb)
2433 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2439 static struct dst_ops ipv4_dst_blackhole_ops = {
2441 .check = ipv4_blackhole_dst_check,
2442 .mtu = ipv4_blackhole_mtu,
2443 .default_advmss = ipv4_default_advmss,
2444 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2445 .redirect = ipv4_rt_blackhole_redirect,
2446 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2447 .neigh_lookup = ipv4_neigh_lookup,
2450 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2452 struct rtable *ort = (struct rtable *) dst_orig;
2455 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2457 struct dst_entry *new = &rt->dst;
2460 new->input = dst_discard;
2461 new->output = dst_discard_out;
2463 new->dev = ort->dst.dev;
2467 rt->rt_is_input = ort->rt_is_input;
2468 rt->rt_iif = ort->rt_iif;
2469 rt->rt_pmtu = ort->rt_pmtu;
2470 rt->rt_mtu_locked = ort->rt_mtu_locked;
2472 rt->rt_genid = rt_genid_ipv4(net);
2473 rt->rt_flags = ort->rt_flags;
2474 rt->rt_type = ort->rt_type;
2475 rt->rt_gateway = ort->rt_gateway;
2476 rt->rt_uses_gateway = ort->rt_uses_gateway;
2478 INIT_LIST_HEAD(&rt->rt_uncached);
2482 dst_release(dst_orig);
2484 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2487 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2488 const struct sock *sk)
2490 struct rtable *rt = __ip_route_output_key(net, flp4);
2495 if (flp4->flowi4_proto)
2496 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2497 flowi4_to_flowi(flp4),
2502 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2504 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2505 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2506 u32 seq, int event, int nowait, unsigned int flags)
2508 struct rtable *rt = skb_rtable(skb);
2510 struct nlmsghdr *nlh;
2511 unsigned long expires = 0;
2513 u32 metrics[RTAX_MAX];
2515 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2519 r = nlmsg_data(nlh);
2520 r->rtm_family = AF_INET;
2521 r->rtm_dst_len = 32;
2523 r->rtm_tos = fl4->flowi4_tos;
2524 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2525 if (nla_put_u32(skb, RTA_TABLE, table_id))
2526 goto nla_put_failure;
2527 r->rtm_type = rt->rt_type;
2528 r->rtm_scope = RT_SCOPE_UNIVERSE;
2529 r->rtm_protocol = RTPROT_UNSPEC;
2530 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2531 if (rt->rt_flags & RTCF_NOTIFY)
2532 r->rtm_flags |= RTM_F_NOTIFY;
2533 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2534 r->rtm_flags |= RTCF_DOREDIRECT;
2536 if (nla_put_in_addr(skb, RTA_DST, dst))
2537 goto nla_put_failure;
2539 r->rtm_src_len = 32;
2540 if (nla_put_in_addr(skb, RTA_SRC, src))
2541 goto nla_put_failure;
2544 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2545 goto nla_put_failure;
2546 #ifdef CONFIG_IP_ROUTE_CLASSID
2547 if (rt->dst.tclassid &&
2548 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2549 goto nla_put_failure;
2551 if (!rt_is_input_route(rt) &&
2552 fl4->saddr != src) {
2553 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2554 goto nla_put_failure;
2556 if (rt->rt_uses_gateway &&
2557 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2558 goto nla_put_failure;
2560 expires = rt->dst.expires;
2562 unsigned long now = jiffies;
2564 if (time_before(now, expires))
2570 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2571 if (rt->rt_pmtu && expires)
2572 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2573 if (rt->rt_mtu_locked && expires)
2574 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2575 if (rtnetlink_put_metrics(skb, metrics) < 0)
2576 goto nla_put_failure;
2578 if (fl4->flowi4_mark &&
2579 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2580 goto nla_put_failure;
2582 error = rt->dst.error;
2584 if (rt_is_input_route(rt)) {
2585 #ifdef CONFIG_IP_MROUTE
2586 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2587 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2588 int err = ipmr_get_route(net, skb,
2589 fl4->saddr, fl4->daddr,
2596 goto nla_put_failure;
2598 if (err == -EMSGSIZE)
2599 goto nla_put_failure;
2605 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2606 goto nla_put_failure;
2609 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2610 goto nla_put_failure;
2612 nlmsg_end(skb, nlh);
2616 nlmsg_cancel(skb, nlh);
2620 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2622 struct net *net = sock_net(in_skb->sk);
2624 struct nlattr *tb[RTA_MAX+1];
2625 struct rtable *rt = NULL;
2632 struct sk_buff *skb;
2633 u32 table_id = RT_TABLE_MAIN;
2635 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2639 rtm = nlmsg_data(nlh);
2641 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2647 /* Reserve room for dummy headers, this skb can pass
2648 through good chunk of routing engine.
2650 skb_reset_mac_header(skb);
2651 skb_reset_network_header(skb);
2653 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2654 ip_hdr(skb)->protocol = IPPROTO_UDP;
2655 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2657 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2658 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2659 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2660 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2662 memset(&fl4, 0, sizeof(fl4));
2665 fl4.flowi4_tos = rtm->rtm_tos;
2666 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2667 fl4.flowi4_mark = mark;
2669 if (netif_index_is_l3_master(net, fl4.flowi4_oif))
2670 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF;
2673 struct net_device *dev;
2675 dev = __dev_get_by_index(net, iif);
2681 skb->protocol = htons(ETH_P_IP);
2685 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2688 rt = skb_rtable(skb);
2689 if (err == 0 && rt->dst.error)
2690 err = -rt->dst.error;
2692 rt = ip_route_output_key(net, &fl4);
2702 skb_dst_set(skb, &rt->dst);
2703 if (rtm->rtm_flags & RTM_F_NOTIFY)
2704 rt->rt_flags |= RTCF_NOTIFY;
2706 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2707 table_id = rt->rt_table_id;
2709 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2710 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2711 RTM_NEWROUTE, 0, 0);
2715 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2724 void ip_rt_multicast_event(struct in_device *in_dev)
2726 rt_cache_flush(dev_net(in_dev->dev));
2729 #ifdef CONFIG_SYSCTL
2730 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2731 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2732 static int ip_rt_gc_elasticity __read_mostly = 8;
2733 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
2735 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2736 void __user *buffer,
2737 size_t *lenp, loff_t *ppos)
2739 struct net *net = (struct net *)__ctl->extra1;
2742 rt_cache_flush(net);
2743 fnhe_genid_bump(net);
2750 static struct ctl_table ipv4_route_table[] = {
2752 .procname = "gc_thresh",
2753 .data = &ipv4_dst_ops.gc_thresh,
2754 .maxlen = sizeof(int),
2756 .proc_handler = proc_dointvec,
2759 .procname = "max_size",
2760 .data = &ip_rt_max_size,
2761 .maxlen = sizeof(int),
2763 .proc_handler = proc_dointvec,
2766 /* Deprecated. Use gc_min_interval_ms */
2768 .procname = "gc_min_interval",
2769 .data = &ip_rt_gc_min_interval,
2770 .maxlen = sizeof(int),
2772 .proc_handler = proc_dointvec_jiffies,
2775 .procname = "gc_min_interval_ms",
2776 .data = &ip_rt_gc_min_interval,
2777 .maxlen = sizeof(int),
2779 .proc_handler = proc_dointvec_ms_jiffies,
2782 .procname = "gc_timeout",
2783 .data = &ip_rt_gc_timeout,
2784 .maxlen = sizeof(int),
2786 .proc_handler = proc_dointvec_jiffies,
2789 .procname = "gc_interval",
2790 .data = &ip_rt_gc_interval,
2791 .maxlen = sizeof(int),
2793 .proc_handler = proc_dointvec_jiffies,
2796 .procname = "redirect_load",
2797 .data = &ip_rt_redirect_load,
2798 .maxlen = sizeof(int),
2800 .proc_handler = proc_dointvec,
2803 .procname = "redirect_number",
2804 .data = &ip_rt_redirect_number,
2805 .maxlen = sizeof(int),
2807 .proc_handler = proc_dointvec,
2810 .procname = "redirect_silence",
2811 .data = &ip_rt_redirect_silence,
2812 .maxlen = sizeof(int),
2814 .proc_handler = proc_dointvec,
2817 .procname = "error_cost",
2818 .data = &ip_rt_error_cost,
2819 .maxlen = sizeof(int),
2821 .proc_handler = proc_dointvec,
2824 .procname = "error_burst",
2825 .data = &ip_rt_error_burst,
2826 .maxlen = sizeof(int),
2828 .proc_handler = proc_dointvec,
2831 .procname = "gc_elasticity",
2832 .data = &ip_rt_gc_elasticity,
2833 .maxlen = sizeof(int),
2835 .proc_handler = proc_dointvec,
2838 .procname = "mtu_expires",
2839 .data = &ip_rt_mtu_expires,
2840 .maxlen = sizeof(int),
2842 .proc_handler = proc_dointvec_jiffies,
2845 .procname = "min_pmtu",
2846 .data = &ip_rt_min_pmtu,
2847 .maxlen = sizeof(int),
2849 .proc_handler = proc_dointvec_minmax,
2850 .extra1 = &ip_min_valid_pmtu,
2853 .procname = "min_adv_mss",
2854 .data = &ip_rt_min_advmss,
2855 .maxlen = sizeof(int),
2857 .proc_handler = proc_dointvec,
2862 static struct ctl_table ipv4_route_flush_table[] = {
2864 .procname = "flush",
2865 .maxlen = sizeof(int),
2867 .proc_handler = ipv4_sysctl_rtcache_flush,
2872 static __net_init int sysctl_route_net_init(struct net *net)
2874 struct ctl_table *tbl;
2876 tbl = ipv4_route_flush_table;
2877 if (!net_eq(net, &init_net)) {
2878 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2882 /* Don't export sysctls to unprivileged users */
2883 if (net->user_ns != &init_user_ns)
2884 tbl[0].procname = NULL;
2886 tbl[0].extra1 = net;
2888 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2889 if (!net->ipv4.route_hdr)
2894 if (tbl != ipv4_route_flush_table)
2900 static __net_exit void sysctl_route_net_exit(struct net *net)
2902 struct ctl_table *tbl;
2904 tbl = net->ipv4.route_hdr->ctl_table_arg;
2905 unregister_net_sysctl_table(net->ipv4.route_hdr);
2906 BUG_ON(tbl == ipv4_route_flush_table);
2910 static __net_initdata struct pernet_operations sysctl_route_ops = {
2911 .init = sysctl_route_net_init,
2912 .exit = sysctl_route_net_exit,
2916 static __net_init int rt_genid_init(struct net *net)
2918 atomic_set(&net->ipv4.rt_genid, 0);
2919 atomic_set(&net->fnhe_genid, 0);
2920 get_random_bytes(&net->ipv4.dev_addr_genid,
2921 sizeof(net->ipv4.dev_addr_genid));
2925 static __net_initdata struct pernet_operations rt_genid_ops = {
2926 .init = rt_genid_init,
2929 static int __net_init ipv4_inetpeer_init(struct net *net)
2931 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2935 inet_peer_base_init(bp);
2936 net->ipv4.peers = bp;
2940 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2942 struct inet_peer_base *bp = net->ipv4.peers;
2944 net->ipv4.peers = NULL;
2945 inetpeer_invalidate_tree(bp);
2949 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2950 .init = ipv4_inetpeer_init,
2951 .exit = ipv4_inetpeer_exit,
2954 #ifdef CONFIG_IP_ROUTE_CLASSID
2955 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2956 #endif /* CONFIG_IP_ROUTE_CLASSID */
2958 int __init ip_rt_init(void)
2964 /* For modern hosts, this will use 2 MB of memory */
2965 idents_hash = alloc_large_system_hash("IP idents",
2966 sizeof(*ip_idents) + sizeof(*ip_tstamps),
2968 16, /* one bucket per 64 KB */
2975 ip_idents = idents_hash;
2977 prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
2979 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
2980 memset(ip_tstamps, 0, (ip_idents_mask + 1) * sizeof(*ip_tstamps));
2982 for_each_possible_cpu(cpu) {
2983 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2985 INIT_LIST_HEAD(&ul->head);
2986 spin_lock_init(&ul->lock);
2988 #ifdef CONFIG_IP_ROUTE_CLASSID
2989 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2991 panic("IP: failed to allocate ip_rt_acct\n");
2994 ipv4_dst_ops.kmem_cachep =
2995 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2996 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2998 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3000 if (dst_entries_init(&ipv4_dst_ops) < 0)
3001 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3003 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3004 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3006 ipv4_dst_ops.gc_thresh = ~0;
3007 ip_rt_max_size = INT_MAX;
3012 if (ip_rt_proc_init())
3013 pr_err("Unable to create route proc files\n");
3018 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3020 #ifdef CONFIG_SYSCTL
3021 register_pernet_subsys(&sysctl_route_ops);
3023 register_pernet_subsys(&rt_genid_ops);
3024 register_pernet_subsys(&ipv4_inetpeer_ops);
3028 #ifdef CONFIG_SYSCTL
3030 * We really need to sanitize the damn ipv4 init order, then all
3031 * this nonsense will go away.
3033 void __init ip_static_sysctl_init(void)
3035 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);