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/string.h>
74 #include <linux/socket.h>
75 #include <linux/sockios.h>
76 #include <linux/errno.h>
78 #include <linux/inet.h>
79 #include <linux/netdevice.h>
80 #include <linux/proc_fs.h>
81 #include <linux/init.h>
82 #include <linux/skbuff.h>
83 #include <linux/inetdevice.h>
84 #include <linux/igmp.h>
85 #include <linux/pkt_sched.h>
86 #include <linux/mroute.h>
87 #include <linux/netfilter_ipv4.h>
88 #include <linux/random.h>
89 #include <linux/rcupdate.h>
90 #include <linux/times.h>
91 #include <linux/slab.h>
92 #include <linux/jhash.h>
94 #include <net/dst_metadata.h>
95 #include <net/net_namespace.h>
96 #include <net/protocol.h>
98 #include <net/route.h>
99 #include <net/inetpeer.h>
100 #include <net/sock.h>
101 #include <net/ip_fib.h>
104 #include <net/icmp.h>
105 #include <net/xfrm.h>
106 #include <net/lwtunnel.h>
107 #include <net/netevent.h>
108 #include <net/rtnetlink.h>
110 #include <linux/sysctl.h>
111 #include <linux/kmemleak.h>
113 #include <net/secure_seq.h>
114 #include <net/ip_tunnels.h>
115 #include <net/l3mdev.h>
117 #define RT_FL_TOS(oldflp4) \
118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
120 #define RT_GC_TIMEOUT (300*HZ)
122 static int ip_rt_max_size;
123 static int ip_rt_redirect_number __read_mostly = 9;
124 static int ip_rt_redirect_load __read_mostly = HZ / 50;
125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
126 static int ip_rt_error_cost __read_mostly = HZ;
127 static int ip_rt_error_burst __read_mostly = 5 * HZ;
128 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
129 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
130 static int ip_rt_min_advmss __read_mostly = 256;
132 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
134 * Interface to generic destination cache.
137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
138 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
139 static unsigned int ipv4_mtu(const struct dst_entry *dst);
140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
141 static void ipv4_link_failure(struct sk_buff *skb);
142 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
143 struct sk_buff *skb, u32 mtu);
144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146 static void ipv4_dst_destroy(struct dst_entry *dst);
148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
158 static struct dst_ops ipv4_dst_ops = {
160 .check = ipv4_dst_check,
161 .default_advmss = ipv4_default_advmss,
163 .cow_metrics = ipv4_cow_metrics,
164 .destroy = ipv4_dst_destroy,
165 .negative_advice = ipv4_negative_advice,
166 .link_failure = ipv4_link_failure,
167 .update_pmtu = ip_rt_update_pmtu,
168 .redirect = ip_do_redirect,
169 .local_out = __ip_local_out,
170 .neigh_lookup = ipv4_neigh_lookup,
173 #define ECN_OR_COST(class) TC_PRIO_##class
175 const __u8 ip_tos2prio[16] = {
177 ECN_OR_COST(BESTEFFORT),
179 ECN_OR_COST(BESTEFFORT),
185 ECN_OR_COST(INTERACTIVE),
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE_BULK,
189 ECN_OR_COST(INTERACTIVE_BULK),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK)
193 EXPORT_SYMBOL(ip_tos2prio);
195 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
196 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
198 #ifdef CONFIG_PROC_FS
199 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
203 return SEQ_START_TOKEN;
206 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
212 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
216 static int rt_cache_seq_show(struct seq_file *seq, void *v)
218 if (v == SEQ_START_TOKEN)
219 seq_printf(seq, "%-127s\n",
220 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
221 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
226 static const struct seq_operations rt_cache_seq_ops = {
227 .start = rt_cache_seq_start,
228 .next = rt_cache_seq_next,
229 .stop = rt_cache_seq_stop,
230 .show = rt_cache_seq_show,
233 static int rt_cache_seq_open(struct inode *inode, struct file *file)
235 return seq_open(file, &rt_cache_seq_ops);
238 static const struct file_operations rt_cache_seq_fops = {
239 .owner = THIS_MODULE,
240 .open = rt_cache_seq_open,
243 .release = seq_release,
247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
252 return SEQ_START_TOKEN;
254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
255 if (!cpu_possible(cpu))
258 return &per_cpu(rt_cache_stat, cpu);
263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
268 if (!cpu_possible(cpu))
271 return &per_cpu(rt_cache_stat, cpu);
277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
282 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
284 struct rt_cache_stat *st = v;
286 if (v == SEQ_START_TOKEN) {
287 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");
291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
293 dst_entries_get_slow(&ipv4_dst_ops),
306 0, /* st->gc_total */
307 0, /* st->gc_ignored */
308 0, /* st->gc_goal_miss */
309 0, /* st->gc_dst_overflow */
310 0, /* st->in_hlist_search */
311 0 /* st->out_hlist_search */
316 static const struct seq_operations rt_cpu_seq_ops = {
317 .start = rt_cpu_seq_start,
318 .next = rt_cpu_seq_next,
319 .stop = rt_cpu_seq_stop,
320 .show = rt_cpu_seq_show,
324 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
326 return seq_open(file, &rt_cpu_seq_ops);
329 static const struct file_operations rt_cpu_seq_fops = {
330 .owner = THIS_MODULE,
331 .open = rt_cpu_seq_open,
334 .release = seq_release,
337 #ifdef CONFIG_IP_ROUTE_CLASSID
338 static int rt_acct_proc_show(struct seq_file *m, void *v)
340 struct ip_rt_acct *dst, *src;
343 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
347 for_each_possible_cpu(i) {
348 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
349 for (j = 0; j < 256; j++) {
350 dst[j].o_bytes += src[j].o_bytes;
351 dst[j].o_packets += src[j].o_packets;
352 dst[j].i_bytes += src[j].i_bytes;
353 dst[j].i_packets += src[j].i_packets;
357 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
362 static int rt_acct_proc_open(struct inode *inode, struct file *file)
364 return single_open(file, rt_acct_proc_show, NULL);
367 static const struct file_operations rt_acct_proc_fops = {
368 .owner = THIS_MODULE,
369 .open = rt_acct_proc_open,
372 .release = single_release,
376 static int __net_init ip_rt_do_proc_init(struct net *net)
378 struct proc_dir_entry *pde;
380 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
385 pde = proc_create("rt_cache", S_IRUGO,
386 net->proc_net_stat, &rt_cpu_seq_fops);
390 #ifdef CONFIG_IP_ROUTE_CLASSID
391 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
397 #ifdef CONFIG_IP_ROUTE_CLASSID
399 remove_proc_entry("rt_cache", net->proc_net_stat);
402 remove_proc_entry("rt_cache", net->proc_net);
407 static void __net_exit ip_rt_do_proc_exit(struct net *net)
409 remove_proc_entry("rt_cache", net->proc_net_stat);
410 remove_proc_entry("rt_cache", net->proc_net);
411 #ifdef CONFIG_IP_ROUTE_CLASSID
412 remove_proc_entry("rt_acct", net->proc_net);
416 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
417 .init = ip_rt_do_proc_init,
418 .exit = ip_rt_do_proc_exit,
421 static int __init ip_rt_proc_init(void)
423 return register_pernet_subsys(&ip_rt_proc_ops);
427 static inline int ip_rt_proc_init(void)
431 #endif /* CONFIG_PROC_FS */
433 static inline bool rt_is_expired(const struct rtable *rth)
435 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
438 void rt_cache_flush(struct net *net)
440 rt_genid_bump_ipv4(net);
443 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
447 struct net_device *dev = dst->dev;
448 const __be32 *pkey = daddr;
449 const struct rtable *rt;
452 rt = (const struct rtable *) dst;
454 pkey = (const __be32 *) &rt->rt_gateway;
456 pkey = &ip_hdr(skb)->daddr;
458 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
461 return neigh_create(&arp_tbl, pkey, dev);
464 #define IP_IDENTS_SZ 2048u
466 static atomic_t *ip_idents __read_mostly;
467 static u32 *ip_tstamps __read_mostly;
469 /* In order to protect privacy, we add a perturbation to identifiers
470 * if one generator is seldom used. This makes hard for an attacker
471 * to infer how many packets were sent between two points in time.
473 u32 ip_idents_reserve(u32 hash, int segs)
475 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
476 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
477 u32 old = ACCESS_ONCE(*p_tstamp);
478 u32 now = (u32)jiffies;
481 if (old != now && cmpxchg(p_tstamp, old, now) == old)
482 delta = prandom_u32_max(now - old);
484 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
486 old = (u32)atomic_read(p_id);
487 new = old + delta + segs;
488 } while (atomic_cmpxchg(p_id, old, new) != old);
492 EXPORT_SYMBOL(ip_idents_reserve);
494 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
496 static u32 ip_idents_hashrnd __read_mostly;
499 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
501 hash = jhash_3words((__force u32)iph->daddr,
502 (__force u32)iph->saddr,
503 iph->protocol ^ net_hash_mix(net),
505 id = ip_idents_reserve(hash, segs);
508 EXPORT_SYMBOL(__ip_select_ident);
510 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
511 const struct iphdr *iph,
513 u8 prot, u32 mark, int flow_flags)
516 const struct inet_sock *inet = inet_sk(sk);
518 oif = sk->sk_bound_dev_if;
520 tos = RT_CONN_FLAGS(sk);
521 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
523 flowi4_init_output(fl4, oif, mark, tos,
524 RT_SCOPE_UNIVERSE, prot,
526 iph->daddr, iph->saddr, 0, 0);
529 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
530 const struct sock *sk)
532 const struct iphdr *iph = ip_hdr(skb);
533 int oif = skb->dev->ifindex;
534 u8 tos = RT_TOS(iph->tos);
535 u8 prot = iph->protocol;
536 u32 mark = skb->mark;
538 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
541 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
543 const struct inet_sock *inet = inet_sk(sk);
544 const struct ip_options_rcu *inet_opt;
545 __be32 daddr = inet->inet_daddr;
548 inet_opt = rcu_dereference(inet->inet_opt);
549 if (inet_opt && inet_opt->opt.srr)
550 daddr = inet_opt->opt.faddr;
551 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
552 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
553 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
554 inet_sk_flowi_flags(sk),
555 daddr, inet->inet_saddr, 0, 0);
559 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
560 const struct sk_buff *skb)
563 build_skb_flow_key(fl4, skb, sk);
565 build_sk_flow_key(fl4, sk);
568 static inline void rt_free(struct rtable *rt)
570 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
573 static DEFINE_SPINLOCK(fnhe_lock);
575 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
579 rt = rcu_dereference(fnhe->fnhe_rth_input);
581 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
584 rt = rcu_dereference(fnhe->fnhe_rth_output);
586 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
591 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
593 struct fib_nh_exception *fnhe, *oldest;
595 oldest = rcu_dereference(hash->chain);
596 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
597 fnhe = rcu_dereference(fnhe->fnhe_next)) {
598 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
601 fnhe_flush_routes(oldest);
605 static inline u32 fnhe_hashfun(__be32 daddr)
607 static u32 fnhe_hashrnd __read_mostly;
610 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
611 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
612 return hash_32(hval, FNHE_HASH_SHIFT);
615 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
617 rt->rt_pmtu = fnhe->fnhe_pmtu;
618 rt->dst.expires = fnhe->fnhe_expires;
621 rt->rt_flags |= RTCF_REDIRECTED;
622 rt->rt_gateway = fnhe->fnhe_gw;
623 rt->rt_uses_gateway = 1;
627 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
628 u32 pmtu, unsigned long expires)
630 struct fnhe_hash_bucket *hash;
631 struct fib_nh_exception *fnhe;
635 u32 hval = fnhe_hashfun(daddr);
637 spin_lock_bh(&fnhe_lock);
639 hash = rcu_dereference(nh->nh_exceptions);
641 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
644 rcu_assign_pointer(nh->nh_exceptions, hash);
650 for (fnhe = rcu_dereference(hash->chain); fnhe;
651 fnhe = rcu_dereference(fnhe->fnhe_next)) {
652 if (fnhe->fnhe_daddr == daddr)
661 fnhe->fnhe_pmtu = pmtu;
662 fnhe->fnhe_expires = max(1UL, expires);
664 /* Update all cached dsts too */
665 rt = rcu_dereference(fnhe->fnhe_rth_input);
667 fill_route_from_fnhe(rt, fnhe);
668 rt = rcu_dereference(fnhe->fnhe_rth_output);
670 fill_route_from_fnhe(rt, fnhe);
672 if (depth > FNHE_RECLAIM_DEPTH)
673 fnhe = fnhe_oldest(hash);
675 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
679 fnhe->fnhe_next = hash->chain;
680 rcu_assign_pointer(hash->chain, fnhe);
682 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
683 fnhe->fnhe_daddr = daddr;
685 fnhe->fnhe_pmtu = pmtu;
686 fnhe->fnhe_expires = expires;
688 /* Exception created; mark the cached routes for the nexthop
689 * stale, so anyone caching it rechecks if this exception
692 rt = rcu_dereference(nh->nh_rth_input);
694 rt->dst.obsolete = DST_OBSOLETE_KILL;
696 for_each_possible_cpu(i) {
697 struct rtable __rcu **prt;
698 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
699 rt = rcu_dereference(*prt);
701 rt->dst.obsolete = DST_OBSOLETE_KILL;
705 fnhe->fnhe_stamp = jiffies;
708 spin_unlock_bh(&fnhe_lock);
711 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
714 __be32 new_gw = icmp_hdr(skb)->un.gateway;
715 __be32 old_gw = ip_hdr(skb)->saddr;
716 struct net_device *dev = skb->dev;
717 struct in_device *in_dev;
718 struct fib_result res;
722 switch (icmp_hdr(skb)->code & 7) {
724 case ICMP_REDIR_NETTOS:
725 case ICMP_REDIR_HOST:
726 case ICMP_REDIR_HOSTTOS:
733 if (rt->rt_gateway != old_gw)
736 in_dev = __in_dev_get_rcu(dev);
741 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
742 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
743 ipv4_is_zeronet(new_gw))
744 goto reject_redirect;
746 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
747 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
748 goto reject_redirect;
749 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
750 goto reject_redirect;
752 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
753 goto reject_redirect;
756 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
758 if (!(n->nud_state & NUD_VALID)) {
759 neigh_event_send(n, NULL);
761 if (fib_lookup(net, fl4, &res, 0) == 0) {
762 struct fib_nh *nh = &FIB_RES_NH(res);
764 update_or_create_fnhe(nh, fl4->daddr, new_gw,
765 0, jiffies + ip_rt_gc_timeout);
768 rt->dst.obsolete = DST_OBSOLETE_KILL;
769 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
776 #ifdef CONFIG_IP_ROUTE_VERBOSE
777 if (IN_DEV_LOG_MARTIANS(in_dev)) {
778 const struct iphdr *iph = (const struct iphdr *) skb->data;
779 __be32 daddr = iph->daddr;
780 __be32 saddr = iph->saddr;
782 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
783 " Advised path = %pI4 -> %pI4\n",
784 &old_gw, dev->name, &new_gw,
791 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
795 const struct iphdr *iph = (const struct iphdr *) skb->data;
796 int oif = skb->dev->ifindex;
797 u8 tos = RT_TOS(iph->tos);
798 u8 prot = iph->protocol;
799 u32 mark = skb->mark;
801 rt = (struct rtable *) dst;
803 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
804 __ip_do_redirect(rt, skb, &fl4, true);
807 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
809 struct rtable *rt = (struct rtable *)dst;
810 struct dst_entry *ret = dst;
813 if (dst->obsolete > 0) {
816 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
827 * 1. The first ip_rt_redirect_number redirects are sent
828 * with exponential backoff, then we stop sending them at all,
829 * assuming that the host ignores our redirects.
830 * 2. If we did not see packets requiring redirects
831 * during ip_rt_redirect_silence, we assume that the host
832 * forgot redirected route and start to send redirects again.
834 * This algorithm is much cheaper and more intelligent than dumb load limiting
837 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
838 * and "frag. need" (breaks PMTU discovery) in icmp.c.
841 void ip_rt_send_redirect(struct sk_buff *skb)
843 struct rtable *rt = skb_rtable(skb);
844 struct in_device *in_dev;
845 struct inet_peer *peer;
851 in_dev = __in_dev_get_rcu(rt->dst.dev);
852 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
856 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
857 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
860 net = dev_net(rt->dst.dev);
861 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
863 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
864 rt_nexthop(rt, ip_hdr(skb)->daddr));
868 /* No redirected packets during ip_rt_redirect_silence;
869 * reset the algorithm.
871 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
872 peer->rate_tokens = 0;
874 /* Too many ignored redirects; do not send anything
875 * set dst.rate_last to the last seen redirected packet.
877 if (peer->rate_tokens >= ip_rt_redirect_number) {
878 peer->rate_last = jiffies;
882 /* Check for load limit; set rate_last to the latest sent
885 if (peer->rate_tokens == 0 ||
888 (ip_rt_redirect_load << peer->rate_tokens)))) {
889 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
891 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
892 peer->rate_last = jiffies;
894 #ifdef CONFIG_IP_ROUTE_VERBOSE
896 peer->rate_tokens == ip_rt_redirect_number)
897 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
898 &ip_hdr(skb)->saddr, inet_iif(skb),
899 &ip_hdr(skb)->daddr, &gw);
906 static int ip_error(struct sk_buff *skb)
908 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
909 struct rtable *rt = skb_rtable(skb);
910 struct inet_peer *peer;
916 /* IP on this device is disabled. */
920 net = dev_net(rt->dst.dev);
921 if (!IN_DEV_FORWARD(in_dev)) {
922 switch (rt->dst.error) {
924 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
928 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
934 switch (rt->dst.error) {
939 code = ICMP_HOST_UNREACH;
942 code = ICMP_NET_UNREACH;
943 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
946 code = ICMP_PKT_FILTERED;
950 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
951 l3mdev_master_ifindex(skb->dev), 1);
956 peer->rate_tokens += now - peer->rate_last;
957 if (peer->rate_tokens > ip_rt_error_burst)
958 peer->rate_tokens = ip_rt_error_burst;
959 peer->rate_last = now;
960 if (peer->rate_tokens >= ip_rt_error_cost)
961 peer->rate_tokens -= ip_rt_error_cost;
967 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
973 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
975 struct dst_entry *dst = &rt->dst;
976 struct fib_result res;
978 if (dst_metric_locked(dst, RTAX_MTU))
981 if (ipv4_mtu(dst) < mtu)
984 if (mtu < ip_rt_min_pmtu)
985 mtu = ip_rt_min_pmtu;
987 if (rt->rt_pmtu == mtu &&
988 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
992 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
993 struct fib_nh *nh = &FIB_RES_NH(res);
995 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
996 jiffies + ip_rt_mtu_expires);
1001 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1002 struct sk_buff *skb, u32 mtu)
1004 struct rtable *rt = (struct rtable *) dst;
1007 ip_rt_build_flow_key(&fl4, sk, skb);
1008 __ip_rt_update_pmtu(rt, &fl4, mtu);
1011 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1012 int oif, u32 mark, u8 protocol, int flow_flags)
1014 const struct iphdr *iph = (const struct iphdr *) skb->data;
1019 mark = IP4_REPLY_MARK(net, skb->mark);
1021 __build_flow_key(&fl4, NULL, iph, oif,
1022 RT_TOS(iph->tos), protocol, mark, flow_flags);
1023 rt = __ip_route_output_key(net, &fl4);
1025 __ip_rt_update_pmtu(rt, &fl4, mtu);
1029 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1031 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1033 const struct iphdr *iph = (const struct iphdr *) skb->data;
1037 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1039 if (!fl4.flowi4_mark)
1040 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1042 rt = __ip_route_output_key(sock_net(sk), &fl4);
1044 __ip_rt_update_pmtu(rt, &fl4, mtu);
1049 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1051 const struct iphdr *iph = (const struct iphdr *) skb->data;
1054 struct dst_entry *odst = NULL;
1059 if (!ip_sk_accept_pmtu(sk))
1062 odst = sk_dst_get(sk);
1064 if (sock_owned_by_user(sk) || !odst) {
1065 __ipv4_sk_update_pmtu(skb, sk, mtu);
1069 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1071 rt = (struct rtable *)odst;
1072 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1073 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1080 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1082 if (!dst_check(&rt->dst, 0)) {
1084 dst_release(&rt->dst);
1086 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1094 sk_dst_set(sk, &rt->dst);
1100 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1102 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1103 int oif, u32 mark, u8 protocol, int flow_flags)
1105 const struct iphdr *iph = (const struct iphdr *) skb->data;
1109 __build_flow_key(&fl4, NULL, iph, oif,
1110 RT_TOS(iph->tos), protocol, mark, flow_flags);
1111 rt = __ip_route_output_key(net, &fl4);
1113 __ip_do_redirect(rt, skb, &fl4, false);
1117 EXPORT_SYMBOL_GPL(ipv4_redirect);
1119 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1121 const struct iphdr *iph = (const struct iphdr *) skb->data;
1125 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1126 rt = __ip_route_output_key(sock_net(sk), &fl4);
1128 __ip_do_redirect(rt, skb, &fl4, false);
1132 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1134 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1136 struct rtable *rt = (struct rtable *) dst;
1138 /* All IPV4 dsts are created with ->obsolete set to the value
1139 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1140 * into this function always.
1142 * When a PMTU/redirect information update invalidates a route,
1143 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1144 * DST_OBSOLETE_DEAD by dst_free().
1146 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1151 static void ipv4_link_failure(struct sk_buff *skb)
1155 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1157 rt = skb_rtable(skb);
1159 dst_set_expires(&rt->dst, 0);
1162 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1164 pr_debug("%s: %pI4 -> %pI4, %s\n",
1165 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1166 skb->dev ? skb->dev->name : "?");
1173 We do not cache source address of outgoing interface,
1174 because it is used only by IP RR, TS and SRR options,
1175 so that it out of fast path.
1177 BTW remember: "addr" is allowed to be not aligned
1181 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1185 if (rt_is_output_route(rt))
1186 src = ip_hdr(skb)->saddr;
1188 struct fib_result res;
1194 memset(&fl4, 0, sizeof(fl4));
1195 fl4.daddr = iph->daddr;
1196 fl4.saddr = iph->saddr;
1197 fl4.flowi4_tos = RT_TOS(iph->tos);
1198 fl4.flowi4_oif = rt->dst.dev->ifindex;
1199 fl4.flowi4_iif = skb->dev->ifindex;
1200 fl4.flowi4_mark = skb->mark;
1203 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1204 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1206 src = inet_select_addr(rt->dst.dev,
1207 rt_nexthop(rt, iph->daddr),
1211 memcpy(addr, &src, 4);
1214 #ifdef CONFIG_IP_ROUTE_CLASSID
1215 static void set_class_tag(struct rtable *rt, u32 tag)
1217 if (!(rt->dst.tclassid & 0xFFFF))
1218 rt->dst.tclassid |= tag & 0xFFFF;
1219 if (!(rt->dst.tclassid & 0xFFFF0000))
1220 rt->dst.tclassid |= tag & 0xFFFF0000;
1224 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1226 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1229 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1231 if (advmss > 65535 - 40)
1232 advmss = 65535 - 40;
1237 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1239 const struct rtable *rt = (const struct rtable *) dst;
1240 unsigned int mtu = rt->rt_pmtu;
1242 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1243 mtu = dst_metric_raw(dst, RTAX_MTU);
1248 mtu = dst->dev->mtu;
1250 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1251 if (rt->rt_uses_gateway && mtu > 576)
1255 return min_t(unsigned int, mtu, IP_MAX_MTU);
1258 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1260 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1261 struct fib_nh_exception *fnhe;
1267 hval = fnhe_hashfun(daddr);
1269 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1270 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1271 if (fnhe->fnhe_daddr == daddr)
1277 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1282 spin_lock_bh(&fnhe_lock);
1284 if (daddr == fnhe->fnhe_daddr) {
1285 struct rtable __rcu **porig;
1286 struct rtable *orig;
1287 int genid = fnhe_genid(dev_net(rt->dst.dev));
1289 if (rt_is_input_route(rt))
1290 porig = &fnhe->fnhe_rth_input;
1292 porig = &fnhe->fnhe_rth_output;
1293 orig = rcu_dereference(*porig);
1295 if (fnhe->fnhe_genid != genid) {
1296 fnhe->fnhe_genid = genid;
1298 fnhe->fnhe_pmtu = 0;
1299 fnhe->fnhe_expires = 0;
1300 fnhe_flush_routes(fnhe);
1303 fill_route_from_fnhe(rt, fnhe);
1304 if (!rt->rt_gateway)
1305 rt->rt_gateway = daddr;
1307 if (!(rt->dst.flags & DST_NOCACHE)) {
1308 rcu_assign_pointer(*porig, rt);
1314 fnhe->fnhe_stamp = jiffies;
1316 spin_unlock_bh(&fnhe_lock);
1321 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1323 struct rtable *orig, *prev, **p;
1326 if (rt_is_input_route(rt)) {
1327 p = (struct rtable **)&nh->nh_rth_input;
1329 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1333 prev = cmpxchg(p, orig, rt);
1343 struct uncached_list {
1345 struct list_head head;
1348 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1350 static void rt_add_uncached_list(struct rtable *rt)
1352 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1354 rt->rt_uncached_list = ul;
1356 spin_lock_bh(&ul->lock);
1357 list_add_tail(&rt->rt_uncached, &ul->head);
1358 spin_unlock_bh(&ul->lock);
1361 static void ipv4_dst_destroy(struct dst_entry *dst)
1363 struct rtable *rt = (struct rtable *) dst;
1365 if (!list_empty(&rt->rt_uncached)) {
1366 struct uncached_list *ul = rt->rt_uncached_list;
1368 spin_lock_bh(&ul->lock);
1369 list_del(&rt->rt_uncached);
1370 spin_unlock_bh(&ul->lock);
1374 void rt_flush_dev(struct net_device *dev)
1376 struct net *net = dev_net(dev);
1380 for_each_possible_cpu(cpu) {
1381 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1383 spin_lock_bh(&ul->lock);
1384 list_for_each_entry(rt, &ul->head, rt_uncached) {
1385 if (rt->dst.dev != dev)
1387 rt->dst.dev = net->loopback_dev;
1388 dev_hold(rt->dst.dev);
1391 spin_unlock_bh(&ul->lock);
1395 static bool rt_cache_valid(const struct rtable *rt)
1398 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1402 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1403 const struct fib_result *res,
1404 struct fib_nh_exception *fnhe,
1405 struct fib_info *fi, u16 type, u32 itag)
1407 bool cached = false;
1410 struct fib_nh *nh = &FIB_RES_NH(*res);
1412 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1413 rt->rt_gateway = nh->nh_gw;
1414 rt->rt_uses_gateway = 1;
1416 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1417 #ifdef CONFIG_IP_ROUTE_CLASSID
1418 rt->dst.tclassid = nh->nh_tclassid;
1420 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1422 cached = rt_bind_exception(rt, fnhe, daddr);
1423 else if (!(rt->dst.flags & DST_NOCACHE))
1424 cached = rt_cache_route(nh, rt);
1425 if (unlikely(!cached)) {
1426 /* Routes we intend to cache in nexthop exception or
1427 * FIB nexthop have the DST_NOCACHE bit clear.
1428 * However, if we are unsuccessful at storing this
1429 * route into the cache we really need to set it.
1431 rt->dst.flags |= DST_NOCACHE;
1432 if (!rt->rt_gateway)
1433 rt->rt_gateway = daddr;
1434 rt_add_uncached_list(rt);
1437 rt_add_uncached_list(rt);
1439 #ifdef CONFIG_IP_ROUTE_CLASSID
1440 #ifdef CONFIG_IP_MULTIPLE_TABLES
1441 set_class_tag(rt, res->tclassid);
1443 set_class_tag(rt, itag);
1447 struct rtable *rt_dst_alloc(struct net_device *dev,
1448 unsigned int flags, u16 type,
1449 bool nopolicy, bool noxfrm, bool will_cache)
1453 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1454 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1455 (nopolicy ? DST_NOPOLICY : 0) |
1456 (noxfrm ? DST_NOXFRM : 0));
1459 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1460 rt->rt_flags = flags;
1462 rt->rt_is_input = 0;
1466 rt->rt_uses_gateway = 0;
1467 rt->rt_table_id = 0;
1468 INIT_LIST_HEAD(&rt->rt_uncached);
1470 rt->dst.output = ip_output;
1471 if (flags & RTCF_LOCAL)
1472 rt->dst.input = ip_local_deliver;
1477 EXPORT_SYMBOL(rt_dst_alloc);
1479 /* called in rcu_read_lock() section */
1480 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1481 u8 tos, struct net_device *dev, int our)
1484 struct in_device *in_dev = __in_dev_get_rcu(dev);
1485 unsigned int flags = RTCF_MULTICAST;
1489 /* Primary sanity checks. */
1494 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1495 skb->protocol != htons(ETH_P_IP))
1498 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1501 if (ipv4_is_zeronet(saddr)) {
1502 if (!ipv4_is_local_multicast(daddr))
1505 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1511 flags |= RTCF_LOCAL;
1513 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1514 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1518 #ifdef CONFIG_IP_ROUTE_CLASSID
1519 rth->dst.tclassid = itag;
1521 rth->dst.output = ip_rt_bug;
1522 rth->rt_is_input= 1;
1524 #ifdef CONFIG_IP_MROUTE
1525 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1526 rth->dst.input = ip_mr_input;
1528 RT_CACHE_STAT_INC(in_slow_mc);
1530 skb_dst_set(skb, &rth->dst);
1542 static void ip_handle_martian_source(struct net_device *dev,
1543 struct in_device *in_dev,
1544 struct sk_buff *skb,
1548 RT_CACHE_STAT_INC(in_martian_src);
1549 #ifdef CONFIG_IP_ROUTE_VERBOSE
1550 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1552 * RFC1812 recommendation, if source is martian,
1553 * the only hint is MAC header.
1555 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1556 &daddr, &saddr, dev->name);
1557 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1558 print_hex_dump(KERN_WARNING, "ll header: ",
1559 DUMP_PREFIX_OFFSET, 16, 1,
1560 skb_mac_header(skb),
1561 dev->hard_header_len, true);
1567 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1569 struct fnhe_hash_bucket *hash;
1570 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1571 u32 hval = fnhe_hashfun(daddr);
1573 spin_lock_bh(&fnhe_lock);
1575 hash = rcu_dereference_protected(nh->nh_exceptions,
1576 lockdep_is_held(&fnhe_lock));
1579 fnhe_p = &hash->chain;
1580 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1582 if (fnhe->fnhe_daddr == daddr) {
1583 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1584 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1585 fnhe_flush_routes(fnhe);
1586 kfree_rcu(fnhe, rcu);
1589 fnhe_p = &fnhe->fnhe_next;
1590 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1591 lockdep_is_held(&fnhe_lock));
1594 spin_unlock_bh(&fnhe_lock);
1597 /* called in rcu_read_lock() section */
1598 static int __mkroute_input(struct sk_buff *skb,
1599 const struct fib_result *res,
1600 struct in_device *in_dev,
1601 __be32 daddr, __be32 saddr, u32 tos)
1603 struct fib_nh_exception *fnhe;
1606 struct in_device *out_dev;
1610 /* get a working reference to the output device */
1611 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1613 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1617 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1618 in_dev->dev, in_dev, &itag);
1620 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1626 do_cache = res->fi && !itag;
1627 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1628 skb->protocol == htons(ETH_P_IP) &&
1629 (IN_DEV_SHARED_MEDIA(out_dev) ||
1630 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1631 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1633 if (skb->protocol != htons(ETH_P_IP)) {
1634 /* Not IP (i.e. ARP). Do not create route, if it is
1635 * invalid for proxy arp. DNAT routes are always valid.
1637 * Proxy arp feature have been extended to allow, ARP
1638 * replies back to the same interface, to support
1639 * Private VLAN switch technologies. See arp.c.
1641 if (out_dev == in_dev &&
1642 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1648 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1651 rth = rcu_dereference(fnhe->fnhe_rth_input);
1652 if (rth && rth->dst.expires &&
1653 time_after(jiffies, rth->dst.expires)) {
1654 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1661 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1664 if (rt_cache_valid(rth)) {
1665 skb_dst_set_noref(skb, &rth->dst);
1670 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1671 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1672 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1678 rth->rt_is_input = 1;
1680 rth->rt_table_id = res->table->tb_id;
1681 RT_CACHE_STAT_INC(in_slow_tot);
1683 rth->dst.input = ip_forward;
1685 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1686 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1687 rth->dst.lwtstate->orig_output = rth->dst.output;
1688 rth->dst.output = lwtunnel_output;
1690 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1691 rth->dst.lwtstate->orig_input = rth->dst.input;
1692 rth->dst.input = lwtunnel_input;
1694 skb_dst_set(skb, &rth->dst);
1701 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1703 /* To make ICMP packets follow the right flow, the multipath hash is
1704 * calculated from the inner IP addresses in reverse order.
1706 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1708 const struct iphdr *outer_iph = ip_hdr(skb);
1709 struct icmphdr _icmph;
1710 const struct icmphdr *icmph;
1711 struct iphdr _inner_iph;
1712 const struct iphdr *inner_iph;
1714 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1717 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1722 if (icmph->type != ICMP_DEST_UNREACH &&
1723 icmph->type != ICMP_REDIRECT &&
1724 icmph->type != ICMP_TIME_EXCEEDED &&
1725 icmph->type != ICMP_PARAMETERPROB) {
1729 inner_iph = skb_header_pointer(skb,
1730 outer_iph->ihl * 4 + sizeof(_icmph),
1731 sizeof(_inner_iph), &_inner_iph);
1735 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1738 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1741 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1743 static int ip_mkroute_input(struct sk_buff *skb,
1744 struct fib_result *res,
1745 const struct flowi4 *fl4,
1746 struct in_device *in_dev,
1747 __be32 daddr, __be32 saddr, u32 tos)
1749 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1750 if (res->fi && res->fi->fib_nhs > 1) {
1753 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1754 h = ip_multipath_icmp_hash(skb);
1756 h = fib_multipath_hash(saddr, daddr);
1757 fib_select_multipath(res, h);
1761 /* create a routing cache entry */
1762 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1766 * NOTE. We drop all the packets that has local source
1767 * addresses, because every properly looped back packet
1768 * must have correct destination already attached by output routine.
1770 * Such approach solves two big problems:
1771 * 1. Not simplex devices are handled properly.
1772 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1773 * called with rcu_read_lock()
1776 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1777 u8 tos, struct net_device *dev)
1779 struct fib_result res;
1780 struct in_device *in_dev = __in_dev_get_rcu(dev);
1781 struct ip_tunnel_info *tun_info;
1783 unsigned int flags = 0;
1787 struct net *net = dev_net(dev);
1790 /* IP on this device is disabled. */
1795 /* Check for the most weird martians, which can be not detected
1799 tun_info = skb_tunnel_info(skb);
1800 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1801 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1803 fl4.flowi4_tun_key.tun_id = 0;
1806 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1807 goto martian_source;
1811 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1814 /* Accept zero addresses only to limited broadcast;
1815 * I even do not know to fix it or not. Waiting for complains :-)
1817 if (ipv4_is_zeronet(saddr))
1818 goto martian_source;
1820 if (ipv4_is_zeronet(daddr))
1821 goto martian_destination;
1823 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1824 * and call it once if daddr or/and saddr are loopback addresses
1826 if (ipv4_is_loopback(daddr)) {
1827 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1828 goto martian_destination;
1829 } else if (ipv4_is_loopback(saddr)) {
1830 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1831 goto martian_source;
1835 * Now we are ready to route packet.
1838 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev);
1839 fl4.flowi4_mark = skb->mark;
1840 fl4.flowi4_tos = tos;
1841 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1842 fl4.flowi4_flags = 0;
1845 err = fib_lookup(net, &fl4, &res, 0);
1847 if (!IN_DEV_FORWARD(in_dev))
1848 err = -EHOSTUNREACH;
1852 if (res.type == RTN_BROADCAST)
1855 if (res.type == RTN_LOCAL) {
1856 err = fib_validate_source(skb, saddr, daddr, tos,
1857 0, dev, in_dev, &itag);
1859 goto martian_source;
1863 if (!IN_DEV_FORWARD(in_dev)) {
1864 err = -EHOSTUNREACH;
1867 if (res.type != RTN_UNICAST)
1868 goto martian_destination;
1870 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1874 if (skb->protocol != htons(ETH_P_IP))
1877 if (!ipv4_is_zeronet(saddr)) {
1878 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1881 goto martian_source;
1883 flags |= RTCF_BROADCAST;
1884 res.type = RTN_BROADCAST;
1885 RT_CACHE_STAT_INC(in_brd);
1891 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1892 if (rt_cache_valid(rth)) {
1893 skb_dst_set_noref(skb, &rth->dst);
1901 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
1902 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1906 rth->dst.output= ip_rt_bug;
1907 #ifdef CONFIG_IP_ROUTE_CLASSID
1908 rth->dst.tclassid = itag;
1910 rth->rt_is_input = 1;
1912 rth->rt_table_id = res.table->tb_id;
1914 RT_CACHE_STAT_INC(in_slow_tot);
1915 if (res.type == RTN_UNREACHABLE) {
1916 rth->dst.input= ip_error;
1917 rth->dst.error= -err;
1918 rth->rt_flags &= ~RTCF_LOCAL;
1921 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1922 rth->dst.flags |= DST_NOCACHE;
1923 rt_add_uncached_list(rth);
1926 skb_dst_set(skb, &rth->dst);
1931 RT_CACHE_STAT_INC(in_no_route);
1932 res.type = RTN_UNREACHABLE;
1938 * Do not cache martian addresses: they should be logged (RFC1812)
1940 martian_destination:
1941 RT_CACHE_STAT_INC(in_martian_dst);
1942 #ifdef CONFIG_IP_ROUTE_VERBOSE
1943 if (IN_DEV_LOG_MARTIANS(in_dev))
1944 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1945 &daddr, &saddr, dev->name);
1957 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1961 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1962 u8 tos, struct net_device *dev)
1968 /* Multicast recognition logic is moved from route cache to here.
1969 The problem was that too many Ethernet cards have broken/missing
1970 hardware multicast filters :-( As result the host on multicasting
1971 network acquires a lot of useless route cache entries, sort of
1972 SDR messages from all the world. Now we try to get rid of them.
1973 Really, provided software IP multicast filter is organized
1974 reasonably (at least, hashed), it does not result in a slowdown
1975 comparing with route cache reject entries.
1976 Note, that multicast routers are not affected, because
1977 route cache entry is created eventually.
1979 if (ipv4_is_multicast(daddr)) {
1980 struct in_device *in_dev = __in_dev_get_rcu(dev);
1983 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1984 ip_hdr(skb)->protocol);
1986 #ifdef CONFIG_IP_MROUTE
1988 (!ipv4_is_local_multicast(daddr) &&
1989 IN_DEV_MFORWARD(in_dev))
1992 int res = ip_route_input_mc(skb, daddr, saddr,
2001 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2005 EXPORT_SYMBOL(ip_route_input_noref);
2007 /* called with rcu_read_lock() */
2008 static struct rtable *__mkroute_output(const struct fib_result *res,
2009 const struct flowi4 *fl4, int orig_oif,
2010 struct net_device *dev_out,
2013 struct fib_info *fi = res->fi;
2014 struct fib_nh_exception *fnhe;
2015 struct in_device *in_dev;
2016 u16 type = res->type;
2020 in_dev = __in_dev_get_rcu(dev_out);
2022 return ERR_PTR(-EINVAL);
2024 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2025 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2026 return ERR_PTR(-EINVAL);
2028 if (ipv4_is_lbcast(fl4->daddr))
2029 type = RTN_BROADCAST;
2030 else if (ipv4_is_multicast(fl4->daddr))
2031 type = RTN_MULTICAST;
2032 else if (ipv4_is_zeronet(fl4->daddr))
2033 return ERR_PTR(-EINVAL);
2035 if (dev_out->flags & IFF_LOOPBACK)
2036 flags |= RTCF_LOCAL;
2039 if (type == RTN_BROADCAST) {
2040 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2042 } else if (type == RTN_MULTICAST) {
2043 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2044 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2046 flags &= ~RTCF_LOCAL;
2049 /* If multicast route do not exist use
2050 * default one, but do not gateway in this case.
2053 if (fi && res->prefixlen < 4)
2055 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2056 (orig_oif != dev_out->ifindex)) {
2057 /* For local routes that require a particular output interface
2058 * we do not want to cache the result. Caching the result
2059 * causes incorrect behaviour when there are multiple source
2060 * addresses on the interface, the end result being that if the
2061 * intended recipient is waiting on that interface for the
2062 * packet he won't receive it because it will be delivered on
2063 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2064 * be set to the loopback interface as well.
2070 do_cache &= fi != NULL;
2072 struct rtable __rcu **prth;
2073 struct fib_nh *nh = &FIB_RES_NH(*res);
2075 fnhe = find_exception(nh, fl4->daddr);
2077 prth = &fnhe->fnhe_rth_output;
2078 rth = rcu_dereference(*prth);
2079 if (rth && rth->dst.expires &&
2080 time_after(jiffies, rth->dst.expires)) {
2081 ip_del_fnhe(nh, fl4->daddr);
2088 if (unlikely(fl4->flowi4_flags &
2089 FLOWI_FLAG_KNOWN_NH &&
2091 nh->nh_scope == RT_SCOPE_LINK))) {
2095 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2096 rth = rcu_dereference(*prth);
2099 if (rt_cache_valid(rth)) {
2100 dst_hold(&rth->dst);
2106 rth = rt_dst_alloc(dev_out, flags, type,
2107 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2108 IN_DEV_CONF_GET(in_dev, NOXFRM),
2111 return ERR_PTR(-ENOBUFS);
2113 rth->rt_iif = orig_oif ? : 0;
2115 rth->rt_table_id = res->table->tb_id;
2117 RT_CACHE_STAT_INC(out_slow_tot);
2119 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2120 if (flags & RTCF_LOCAL &&
2121 !(dev_out->flags & IFF_LOOPBACK)) {
2122 rth->dst.output = ip_mc_output;
2123 RT_CACHE_STAT_INC(out_slow_mc);
2125 #ifdef CONFIG_IP_MROUTE
2126 if (type == RTN_MULTICAST) {
2127 if (IN_DEV_MFORWARD(in_dev) &&
2128 !ipv4_is_local_multicast(fl4->daddr)) {
2129 rth->dst.input = ip_mr_input;
2130 rth->dst.output = ip_mc_output;
2136 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2137 if (lwtunnel_output_redirect(rth->dst.lwtstate))
2138 rth->dst.output = lwtunnel_output;
2144 * Major route resolver routine.
2147 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2150 struct net_device *dev_out = NULL;
2151 __u8 tos = RT_FL_TOS(fl4);
2152 unsigned int flags = 0;
2153 struct fib_result res;
2157 int err = -ENETUNREACH;
2163 orig_oif = fl4->flowi4_oif;
2165 master_idx = l3mdev_master_ifindex_by_index(net, fl4->flowi4_oif);
2167 fl4->flowi4_oif = master_idx;
2168 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2169 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2170 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2171 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2175 rth = ERR_PTR(-EINVAL);
2176 if (ipv4_is_multicast(fl4->saddr) ||
2177 ipv4_is_lbcast(fl4->saddr) ||
2178 ipv4_is_zeronet(fl4->saddr))
2181 /* I removed check for oif == dev_out->oif here.
2182 It was wrong for two reasons:
2183 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2184 is assigned to multiple interfaces.
2185 2. Moreover, we are allowed to send packets with saddr
2186 of another iface. --ANK
2189 if (fl4->flowi4_oif == 0 &&
2190 (ipv4_is_multicast(fl4->daddr) ||
2191 ipv4_is_lbcast(fl4->daddr))) {
2192 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2193 dev_out = __ip_dev_find(net, fl4->saddr, false);
2197 /* Special hack: user can direct multicasts
2198 and limited broadcast via necessary interface
2199 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2200 This hack is not just for fun, it allows
2201 vic,vat and friends to work.
2202 They bind socket to loopback, set ttl to zero
2203 and expect that it will work.
2204 From the viewpoint of routing cache they are broken,
2205 because we are not allowed to build multicast path
2206 with loopback source addr (look, routing cache
2207 cannot know, that ttl is zero, so that packet
2208 will not leave this host and route is valid).
2209 Luckily, this hack is good workaround.
2212 fl4->flowi4_oif = dev_out->ifindex;
2216 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2217 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2218 if (!__ip_dev_find(net, fl4->saddr, false))
2224 if (fl4->flowi4_oif) {
2225 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2226 rth = ERR_PTR(-ENODEV);
2230 /* RACE: Check return value of inet_select_addr instead. */
2231 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2232 rth = ERR_PTR(-ENETUNREACH);
2235 if (ipv4_is_local_multicast(fl4->daddr) ||
2236 ipv4_is_lbcast(fl4->daddr) ||
2237 fl4->flowi4_proto == IPPROTO_IGMP) {
2239 fl4->saddr = inet_select_addr(dev_out, 0,
2244 if (ipv4_is_multicast(fl4->daddr))
2245 fl4->saddr = inet_select_addr(dev_out, 0,
2247 else if (!fl4->daddr)
2248 fl4->saddr = inet_select_addr(dev_out, 0,
2252 rth = l3mdev_get_rtable(dev_out, fl4);
2258 fl4->daddr = fl4->saddr;
2260 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2261 dev_out = net->loopback_dev;
2262 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2263 res.type = RTN_LOCAL;
2264 flags |= RTCF_LOCAL;
2268 err = fib_lookup(net, fl4, &res, 0);
2272 if (fl4->flowi4_oif &&
2273 !netif_index_is_l3_master(net, fl4->flowi4_oif)) {
2274 /* Apparently, routing tables are wrong. Assume,
2275 that the destination is on link.
2278 Because we are allowed to send to iface
2279 even if it has NO routes and NO assigned
2280 addresses. When oif is specified, routing
2281 tables are looked up with only one purpose:
2282 to catch if destination is gatewayed, rather than
2283 direct. Moreover, if MSG_DONTROUTE is set,
2284 we send packet, ignoring both routing tables
2285 and ifaddr state. --ANK
2288 We could make it even if oif is unknown,
2289 likely IPv6, but we do not.
2292 if (fl4->saddr == 0)
2293 fl4->saddr = inet_select_addr(dev_out, 0,
2295 res.type = RTN_UNICAST;
2302 if (res.type == RTN_LOCAL) {
2304 if (res.fi->fib_prefsrc)
2305 fl4->saddr = res.fi->fib_prefsrc;
2307 fl4->saddr = fl4->daddr;
2309 dev_out = net->loopback_dev;
2310 fl4->flowi4_oif = dev_out->ifindex;
2311 flags |= RTCF_LOCAL;
2315 fib_select_path(net, &res, fl4, mp_hash);
2317 dev_out = FIB_RES_DEV(res);
2318 fl4->flowi4_oif = dev_out->ifindex;
2322 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2328 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2330 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2335 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2337 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2339 return mtu ? : dst->dev->mtu;
2342 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2343 struct sk_buff *skb, u32 mtu)
2347 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2348 struct sk_buff *skb)
2352 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2358 static struct dst_ops ipv4_dst_blackhole_ops = {
2360 .check = ipv4_blackhole_dst_check,
2361 .mtu = ipv4_blackhole_mtu,
2362 .default_advmss = ipv4_default_advmss,
2363 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2364 .redirect = ipv4_rt_blackhole_redirect,
2365 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2366 .neigh_lookup = ipv4_neigh_lookup,
2369 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2371 struct rtable *ort = (struct rtable *) dst_orig;
2374 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2376 struct dst_entry *new = &rt->dst;
2379 new->input = dst_discard;
2380 new->output = dst_discard_out;
2382 new->dev = ort->dst.dev;
2386 rt->rt_is_input = ort->rt_is_input;
2387 rt->rt_iif = ort->rt_iif;
2388 rt->rt_pmtu = ort->rt_pmtu;
2390 rt->rt_genid = rt_genid_ipv4(net);
2391 rt->rt_flags = ort->rt_flags;
2392 rt->rt_type = ort->rt_type;
2393 rt->rt_gateway = ort->rt_gateway;
2394 rt->rt_uses_gateway = ort->rt_uses_gateway;
2396 INIT_LIST_HEAD(&rt->rt_uncached);
2400 dst_release(dst_orig);
2402 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2405 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2406 const struct sock *sk)
2408 struct rtable *rt = __ip_route_output_key(net, flp4);
2413 if (flp4->flowi4_proto)
2414 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2415 flowi4_to_flowi(flp4),
2420 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2422 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2423 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2424 u32 seq, int event, int nowait, unsigned int flags)
2426 struct rtable *rt = skb_rtable(skb);
2428 struct nlmsghdr *nlh;
2429 unsigned long expires = 0;
2431 u32 metrics[RTAX_MAX];
2433 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2437 r = nlmsg_data(nlh);
2438 r->rtm_family = AF_INET;
2439 r->rtm_dst_len = 32;
2441 r->rtm_tos = fl4->flowi4_tos;
2442 r->rtm_table = table_id;
2443 if (nla_put_u32(skb, RTA_TABLE, table_id))
2444 goto nla_put_failure;
2445 r->rtm_type = rt->rt_type;
2446 r->rtm_scope = RT_SCOPE_UNIVERSE;
2447 r->rtm_protocol = RTPROT_UNSPEC;
2448 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2449 if (rt->rt_flags & RTCF_NOTIFY)
2450 r->rtm_flags |= RTM_F_NOTIFY;
2451 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2452 r->rtm_flags |= RTCF_DOREDIRECT;
2454 if (nla_put_in_addr(skb, RTA_DST, dst))
2455 goto nla_put_failure;
2457 r->rtm_src_len = 32;
2458 if (nla_put_in_addr(skb, RTA_SRC, src))
2459 goto nla_put_failure;
2462 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2463 goto nla_put_failure;
2464 #ifdef CONFIG_IP_ROUTE_CLASSID
2465 if (rt->dst.tclassid &&
2466 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2467 goto nla_put_failure;
2469 if (!rt_is_input_route(rt) &&
2470 fl4->saddr != src) {
2471 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2472 goto nla_put_failure;
2474 if (rt->rt_uses_gateway &&
2475 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2476 goto nla_put_failure;
2478 expires = rt->dst.expires;
2480 unsigned long now = jiffies;
2482 if (time_before(now, expires))
2488 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2489 if (rt->rt_pmtu && expires)
2490 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2491 if (rtnetlink_put_metrics(skb, metrics) < 0)
2492 goto nla_put_failure;
2494 if (fl4->flowi4_mark &&
2495 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2496 goto nla_put_failure;
2498 error = rt->dst.error;
2500 if (rt_is_input_route(rt)) {
2501 #ifdef CONFIG_IP_MROUTE
2502 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2503 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2504 int err = ipmr_get_route(net, skb,
2505 fl4->saddr, fl4->daddr,
2512 goto nla_put_failure;
2514 if (err == -EMSGSIZE)
2515 goto nla_put_failure;
2521 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2522 goto nla_put_failure;
2525 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2526 goto nla_put_failure;
2528 nlmsg_end(skb, nlh);
2532 nlmsg_cancel(skb, nlh);
2536 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2538 struct net *net = sock_net(in_skb->sk);
2540 struct nlattr *tb[RTA_MAX+1];
2541 struct rtable *rt = NULL;
2548 struct sk_buff *skb;
2549 u32 table_id = RT_TABLE_MAIN;
2551 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2555 rtm = nlmsg_data(nlh);
2557 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2563 /* Reserve room for dummy headers, this skb can pass
2564 through good chunk of routing engine.
2566 skb_reset_mac_header(skb);
2567 skb_reset_network_header(skb);
2569 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2570 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2571 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2573 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2574 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2575 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2576 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2578 memset(&fl4, 0, sizeof(fl4));
2581 fl4.flowi4_tos = rtm->rtm_tos;
2582 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2583 fl4.flowi4_mark = mark;
2585 if (netif_index_is_l3_master(net, fl4.flowi4_oif))
2586 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF;
2589 struct net_device *dev;
2591 dev = __dev_get_by_index(net, iif);
2597 skb->protocol = htons(ETH_P_IP);
2601 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2604 rt = skb_rtable(skb);
2605 if (err == 0 && rt->dst.error)
2606 err = -rt->dst.error;
2608 rt = ip_route_output_key(net, &fl4);
2618 skb_dst_set(skb, &rt->dst);
2619 if (rtm->rtm_flags & RTM_F_NOTIFY)
2620 rt->rt_flags |= RTCF_NOTIFY;
2622 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2623 table_id = rt->rt_table_id;
2625 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2626 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2627 RTM_NEWROUTE, 0, 0);
2631 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2640 void ip_rt_multicast_event(struct in_device *in_dev)
2642 rt_cache_flush(dev_net(in_dev->dev));
2645 #ifdef CONFIG_SYSCTL
2646 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2647 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2648 static int ip_rt_gc_elasticity __read_mostly = 8;
2650 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2651 void __user *buffer,
2652 size_t *lenp, loff_t *ppos)
2654 struct net *net = (struct net *)__ctl->extra1;
2657 rt_cache_flush(net);
2658 fnhe_genid_bump(net);
2665 static struct ctl_table ipv4_route_table[] = {
2667 .procname = "gc_thresh",
2668 .data = &ipv4_dst_ops.gc_thresh,
2669 .maxlen = sizeof(int),
2671 .proc_handler = proc_dointvec,
2674 .procname = "max_size",
2675 .data = &ip_rt_max_size,
2676 .maxlen = sizeof(int),
2678 .proc_handler = proc_dointvec,
2681 /* Deprecated. Use gc_min_interval_ms */
2683 .procname = "gc_min_interval",
2684 .data = &ip_rt_gc_min_interval,
2685 .maxlen = sizeof(int),
2687 .proc_handler = proc_dointvec_jiffies,
2690 .procname = "gc_min_interval_ms",
2691 .data = &ip_rt_gc_min_interval,
2692 .maxlen = sizeof(int),
2694 .proc_handler = proc_dointvec_ms_jiffies,
2697 .procname = "gc_timeout",
2698 .data = &ip_rt_gc_timeout,
2699 .maxlen = sizeof(int),
2701 .proc_handler = proc_dointvec_jiffies,
2704 .procname = "gc_interval",
2705 .data = &ip_rt_gc_interval,
2706 .maxlen = sizeof(int),
2708 .proc_handler = proc_dointvec_jiffies,
2711 .procname = "redirect_load",
2712 .data = &ip_rt_redirect_load,
2713 .maxlen = sizeof(int),
2715 .proc_handler = proc_dointvec,
2718 .procname = "redirect_number",
2719 .data = &ip_rt_redirect_number,
2720 .maxlen = sizeof(int),
2722 .proc_handler = proc_dointvec,
2725 .procname = "redirect_silence",
2726 .data = &ip_rt_redirect_silence,
2727 .maxlen = sizeof(int),
2729 .proc_handler = proc_dointvec,
2732 .procname = "error_cost",
2733 .data = &ip_rt_error_cost,
2734 .maxlen = sizeof(int),
2736 .proc_handler = proc_dointvec,
2739 .procname = "error_burst",
2740 .data = &ip_rt_error_burst,
2741 .maxlen = sizeof(int),
2743 .proc_handler = proc_dointvec,
2746 .procname = "gc_elasticity",
2747 .data = &ip_rt_gc_elasticity,
2748 .maxlen = sizeof(int),
2750 .proc_handler = proc_dointvec,
2753 .procname = "mtu_expires",
2754 .data = &ip_rt_mtu_expires,
2755 .maxlen = sizeof(int),
2757 .proc_handler = proc_dointvec_jiffies,
2760 .procname = "min_pmtu",
2761 .data = &ip_rt_min_pmtu,
2762 .maxlen = sizeof(int),
2764 .proc_handler = proc_dointvec,
2767 .procname = "min_adv_mss",
2768 .data = &ip_rt_min_advmss,
2769 .maxlen = sizeof(int),
2771 .proc_handler = proc_dointvec,
2776 static struct ctl_table ipv4_route_flush_table[] = {
2778 .procname = "flush",
2779 .maxlen = sizeof(int),
2781 .proc_handler = ipv4_sysctl_rtcache_flush,
2786 static __net_init int sysctl_route_net_init(struct net *net)
2788 struct ctl_table *tbl;
2790 tbl = ipv4_route_flush_table;
2791 if (!net_eq(net, &init_net)) {
2792 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2796 /* Don't export sysctls to unprivileged users */
2797 if (net->user_ns != &init_user_ns)
2798 tbl[0].procname = NULL;
2800 tbl[0].extra1 = net;
2802 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2803 if (!net->ipv4.route_hdr)
2808 if (tbl != ipv4_route_flush_table)
2814 static __net_exit void sysctl_route_net_exit(struct net *net)
2816 struct ctl_table *tbl;
2818 tbl = net->ipv4.route_hdr->ctl_table_arg;
2819 unregister_net_sysctl_table(net->ipv4.route_hdr);
2820 BUG_ON(tbl == ipv4_route_flush_table);
2824 static __net_initdata struct pernet_operations sysctl_route_ops = {
2825 .init = sysctl_route_net_init,
2826 .exit = sysctl_route_net_exit,
2830 static __net_init int rt_genid_init(struct net *net)
2832 atomic_set(&net->ipv4.rt_genid, 0);
2833 atomic_set(&net->fnhe_genid, 0);
2834 get_random_bytes(&net->ipv4.dev_addr_genid,
2835 sizeof(net->ipv4.dev_addr_genid));
2839 static __net_initdata struct pernet_operations rt_genid_ops = {
2840 .init = rt_genid_init,
2843 static int __net_init ipv4_inetpeer_init(struct net *net)
2845 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2849 inet_peer_base_init(bp);
2850 net->ipv4.peers = bp;
2854 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2856 struct inet_peer_base *bp = net->ipv4.peers;
2858 net->ipv4.peers = NULL;
2859 inetpeer_invalidate_tree(bp);
2863 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2864 .init = ipv4_inetpeer_init,
2865 .exit = ipv4_inetpeer_exit,
2868 #ifdef CONFIG_IP_ROUTE_CLASSID
2869 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2870 #endif /* CONFIG_IP_ROUTE_CLASSID */
2872 int __init ip_rt_init(void)
2877 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2879 panic("IP: failed to allocate ip_idents\n");
2881 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2883 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2885 panic("IP: failed to allocate ip_tstamps\n");
2887 for_each_possible_cpu(cpu) {
2888 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2890 INIT_LIST_HEAD(&ul->head);
2891 spin_lock_init(&ul->lock);
2893 #ifdef CONFIG_IP_ROUTE_CLASSID
2894 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2896 panic("IP: failed to allocate ip_rt_acct\n");
2899 ipv4_dst_ops.kmem_cachep =
2900 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2901 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2903 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2905 if (dst_entries_init(&ipv4_dst_ops) < 0)
2906 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2908 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2909 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2911 ipv4_dst_ops.gc_thresh = ~0;
2912 ip_rt_max_size = INT_MAX;
2917 if (ip_rt_proc_init())
2918 pr_err("Unable to create route proc files\n");
2923 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2925 #ifdef CONFIG_SYSCTL
2926 register_pernet_subsys(&sysctl_route_ops);
2928 register_pernet_subsys(&rt_genid_ops);
2929 register_pernet_subsys(&ipv4_inetpeer_ops);
2933 #ifdef CONFIG_SYSCTL
2935 * We really need to sanitize the damn ipv4 init order, then all
2936 * this nonsense will go away.
2938 void __init ip_static_sysctl_init(void)
2940 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);