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 <linux/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>
112 #include <net/secure_seq.h>
113 #include <net/ip_tunnels.h>
114 #include <net/l3mdev.h>
116 #include "fib_lookup.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,
159 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
161 static struct dst_ops ipv4_dst_ops = {
163 .check = ipv4_dst_check,
164 .default_advmss = ipv4_default_advmss,
166 .cow_metrics = ipv4_cow_metrics,
167 .destroy = ipv4_dst_destroy,
168 .negative_advice = ipv4_negative_advice,
169 .link_failure = ipv4_link_failure,
170 .update_pmtu = ip_rt_update_pmtu,
171 .redirect = ip_do_redirect,
172 .local_out = __ip_local_out,
173 .neigh_lookup = ipv4_neigh_lookup,
174 .confirm_neigh = ipv4_confirm_neigh,
177 #define ECN_OR_COST(class) TC_PRIO_##class
179 const __u8 ip_tos2prio[16] = {
181 ECN_OR_COST(BESTEFFORT),
183 ECN_OR_COST(BESTEFFORT),
189 ECN_OR_COST(INTERACTIVE),
191 ECN_OR_COST(INTERACTIVE),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK),
194 TC_PRIO_INTERACTIVE_BULK,
195 ECN_OR_COST(INTERACTIVE_BULK)
197 EXPORT_SYMBOL(ip_tos2prio);
199 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
200 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
202 #ifdef CONFIG_PROC_FS
203 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
207 return SEQ_START_TOKEN;
210 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
216 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
220 static int rt_cache_seq_show(struct seq_file *seq, void *v)
222 if (v == SEQ_START_TOKEN)
223 seq_printf(seq, "%-127s\n",
224 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
225 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
230 static const struct seq_operations rt_cache_seq_ops = {
231 .start = rt_cache_seq_start,
232 .next = rt_cache_seq_next,
233 .stop = rt_cache_seq_stop,
234 .show = rt_cache_seq_show,
237 static int rt_cache_seq_open(struct inode *inode, struct file *file)
239 return seq_open(file, &rt_cache_seq_ops);
242 static const struct file_operations rt_cache_seq_fops = {
243 .open = rt_cache_seq_open,
246 .release = seq_release,
250 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
255 return SEQ_START_TOKEN;
257 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
258 if (!cpu_possible(cpu))
261 return &per_cpu(rt_cache_stat, cpu);
266 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
270 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
271 if (!cpu_possible(cpu))
274 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 .open = rt_cpu_seq_open,
336 .release = seq_release,
339 #ifdef CONFIG_IP_ROUTE_CLASSID
340 static int rt_acct_proc_show(struct seq_file *m, void *v)
342 struct ip_rt_acct *dst, *src;
345 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
349 for_each_possible_cpu(i) {
350 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
351 for (j = 0; j < 256; j++) {
352 dst[j].o_bytes += src[j].o_bytes;
353 dst[j].o_packets += src[j].o_packets;
354 dst[j].i_bytes += src[j].i_bytes;
355 dst[j].i_packets += src[j].i_packets;
359 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
365 static int __net_init ip_rt_do_proc_init(struct net *net)
367 struct proc_dir_entry *pde;
369 pde = proc_create("rt_cache", 0444, net->proc_net,
374 pde = proc_create("rt_cache", 0444,
375 net->proc_net_stat, &rt_cpu_seq_fops);
379 #ifdef CONFIG_IP_ROUTE_CLASSID
380 pde = proc_create_single("rt_acct", 0, net->proc_net,
387 #ifdef CONFIG_IP_ROUTE_CLASSID
389 remove_proc_entry("rt_cache", net->proc_net_stat);
392 remove_proc_entry("rt_cache", net->proc_net);
397 static void __net_exit ip_rt_do_proc_exit(struct net *net)
399 remove_proc_entry("rt_cache", net->proc_net_stat);
400 remove_proc_entry("rt_cache", net->proc_net);
401 #ifdef CONFIG_IP_ROUTE_CLASSID
402 remove_proc_entry("rt_acct", net->proc_net);
406 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
407 .init = ip_rt_do_proc_init,
408 .exit = ip_rt_do_proc_exit,
411 static int __init ip_rt_proc_init(void)
413 return register_pernet_subsys(&ip_rt_proc_ops);
417 static inline int ip_rt_proc_init(void)
421 #endif /* CONFIG_PROC_FS */
423 static inline bool rt_is_expired(const struct rtable *rth)
425 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
428 void rt_cache_flush(struct net *net)
430 rt_genid_bump_ipv4(net);
433 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
437 struct net_device *dev = dst->dev;
438 const __be32 *pkey = daddr;
439 const struct rtable *rt;
442 rt = (const struct rtable *) dst;
444 pkey = (const __be32 *) &rt->rt_gateway;
446 pkey = &ip_hdr(skb)->daddr;
448 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
451 return neigh_create(&arp_tbl, pkey, dev);
454 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
456 struct net_device *dev = dst->dev;
457 const __be32 *pkey = daddr;
458 const struct rtable *rt;
460 rt = (const struct rtable *)dst;
462 pkey = (const __be32 *)&rt->rt_gateway;
465 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
468 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
471 #define IP_IDENTS_SZ 2048u
473 static atomic_t *ip_idents __read_mostly;
474 static u32 *ip_tstamps __read_mostly;
476 /* In order to protect privacy, we add a perturbation to identifiers
477 * if one generator is seldom used. This makes hard for an attacker
478 * to infer how many packets were sent between two points in time.
480 u32 ip_idents_reserve(u32 hash, int segs)
482 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
483 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
484 u32 old = READ_ONCE(*p_tstamp);
485 u32 now = (u32)jiffies;
488 if (old != now && cmpxchg(p_tstamp, old, now) == old)
489 delta = prandom_u32_max(now - old);
491 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
493 old = (u32)atomic_read(p_id);
494 new = old + delta + segs;
495 } while (atomic_cmpxchg(p_id, old, new) != old);
499 EXPORT_SYMBOL(ip_idents_reserve);
501 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
503 static u32 ip_idents_hashrnd __read_mostly;
506 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
508 hash = jhash_3words((__force u32)iph->daddr,
509 (__force u32)iph->saddr,
510 iph->protocol ^ net_hash_mix(net),
512 id = ip_idents_reserve(hash, segs);
515 EXPORT_SYMBOL(__ip_select_ident);
517 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
518 const struct sock *sk,
519 const struct iphdr *iph,
521 u8 prot, u32 mark, int flow_flags)
524 const struct inet_sock *inet = inet_sk(sk);
526 oif = sk->sk_bound_dev_if;
528 tos = RT_CONN_FLAGS(sk);
529 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
531 flowi4_init_output(fl4, oif, mark, tos,
532 RT_SCOPE_UNIVERSE, prot,
534 iph->daddr, iph->saddr, 0, 0,
535 sock_net_uid(net, sk));
538 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
539 const struct sock *sk)
541 const struct net *net = dev_net(skb->dev);
542 const struct iphdr *iph = ip_hdr(skb);
543 int oif = skb->dev->ifindex;
544 u8 tos = RT_TOS(iph->tos);
545 u8 prot = iph->protocol;
546 u32 mark = skb->mark;
548 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
551 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
553 const struct inet_sock *inet = inet_sk(sk);
554 const struct ip_options_rcu *inet_opt;
555 __be32 daddr = inet->inet_daddr;
558 inet_opt = rcu_dereference(inet->inet_opt);
559 if (inet_opt && inet_opt->opt.srr)
560 daddr = inet_opt->opt.faddr;
561 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
562 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
563 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
564 inet_sk_flowi_flags(sk),
565 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
569 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
570 const struct sk_buff *skb)
573 build_skb_flow_key(fl4, skb, sk);
575 build_sk_flow_key(fl4, sk);
578 static DEFINE_SPINLOCK(fnhe_lock);
580 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
584 rt = rcu_dereference(fnhe->fnhe_rth_input);
586 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
587 dst_dev_put(&rt->dst);
588 dst_release(&rt->dst);
590 rt = rcu_dereference(fnhe->fnhe_rth_output);
592 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
593 dst_dev_put(&rt->dst);
594 dst_release(&rt->dst);
598 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
600 struct fib_nh_exception *fnhe, *oldest;
602 oldest = rcu_dereference(hash->chain);
603 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
604 fnhe = rcu_dereference(fnhe->fnhe_next)) {
605 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
608 fnhe_flush_routes(oldest);
612 static inline u32 fnhe_hashfun(__be32 daddr)
614 static u32 fnhe_hashrnd __read_mostly;
617 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
618 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
619 return hash_32(hval, FNHE_HASH_SHIFT);
622 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
624 rt->rt_pmtu = fnhe->fnhe_pmtu;
625 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
626 rt->dst.expires = fnhe->fnhe_expires;
629 rt->rt_flags |= RTCF_REDIRECTED;
630 rt->rt_gateway = fnhe->fnhe_gw;
631 rt->rt_uses_gateway = 1;
635 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
636 u32 pmtu, bool lock, unsigned long expires)
638 struct fnhe_hash_bucket *hash;
639 struct fib_nh_exception *fnhe;
645 genid = fnhe_genid(dev_net(nh->nh_dev));
646 hval = fnhe_hashfun(daddr);
648 spin_lock_bh(&fnhe_lock);
650 hash = rcu_dereference(nh->nh_exceptions);
652 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
655 rcu_assign_pointer(nh->nh_exceptions, hash);
661 for (fnhe = rcu_dereference(hash->chain); fnhe;
662 fnhe = rcu_dereference(fnhe->fnhe_next)) {
663 if (fnhe->fnhe_daddr == daddr)
669 if (fnhe->fnhe_genid != genid)
670 fnhe->fnhe_genid = genid;
674 fnhe->fnhe_pmtu = pmtu;
675 fnhe->fnhe_mtu_locked = lock;
677 fnhe->fnhe_expires = max(1UL, expires);
678 /* Update all cached dsts too */
679 rt = rcu_dereference(fnhe->fnhe_rth_input);
681 fill_route_from_fnhe(rt, fnhe);
682 rt = rcu_dereference(fnhe->fnhe_rth_output);
684 fill_route_from_fnhe(rt, fnhe);
686 if (depth > FNHE_RECLAIM_DEPTH)
687 fnhe = fnhe_oldest(hash);
689 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
693 fnhe->fnhe_next = hash->chain;
694 rcu_assign_pointer(hash->chain, fnhe);
696 fnhe->fnhe_genid = genid;
697 fnhe->fnhe_daddr = daddr;
699 fnhe->fnhe_pmtu = pmtu;
700 fnhe->fnhe_mtu_locked = lock;
701 fnhe->fnhe_expires = max(1UL, expires);
703 /* Exception created; mark the cached routes for the nexthop
704 * stale, so anyone caching it rechecks if this exception
707 rt = rcu_dereference(nh->nh_rth_input);
709 rt->dst.obsolete = DST_OBSOLETE_KILL;
711 for_each_possible_cpu(i) {
712 struct rtable __rcu **prt;
713 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
714 rt = rcu_dereference(*prt);
716 rt->dst.obsolete = DST_OBSOLETE_KILL;
720 fnhe->fnhe_stamp = jiffies;
723 spin_unlock_bh(&fnhe_lock);
726 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
729 __be32 new_gw = icmp_hdr(skb)->un.gateway;
730 __be32 old_gw = ip_hdr(skb)->saddr;
731 struct net_device *dev = skb->dev;
732 struct in_device *in_dev;
733 struct fib_result res;
737 switch (icmp_hdr(skb)->code & 7) {
739 case ICMP_REDIR_NETTOS:
740 case ICMP_REDIR_HOST:
741 case ICMP_REDIR_HOSTTOS:
748 if (rt->rt_gateway != old_gw)
751 in_dev = __in_dev_get_rcu(dev);
756 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
757 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
758 ipv4_is_zeronet(new_gw))
759 goto reject_redirect;
761 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
762 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
763 goto reject_redirect;
764 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
765 goto reject_redirect;
767 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
768 goto reject_redirect;
771 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
773 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
775 if (!(n->nud_state & NUD_VALID)) {
776 neigh_event_send(n, NULL);
778 if (fib_lookup(net, fl4, &res, 0) == 0) {
779 struct fib_nh *nh = &FIB_RES_NH(res);
781 update_or_create_fnhe(nh, fl4->daddr, new_gw,
783 jiffies + ip_rt_gc_timeout);
786 rt->dst.obsolete = DST_OBSOLETE_KILL;
787 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
794 #ifdef CONFIG_IP_ROUTE_VERBOSE
795 if (IN_DEV_LOG_MARTIANS(in_dev)) {
796 const struct iphdr *iph = (const struct iphdr *) skb->data;
797 __be32 daddr = iph->daddr;
798 __be32 saddr = iph->saddr;
800 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
801 " Advised path = %pI4 -> %pI4\n",
802 &old_gw, dev->name, &new_gw,
809 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
813 const struct iphdr *iph = (const struct iphdr *) skb->data;
814 struct net *net = dev_net(skb->dev);
815 int oif = skb->dev->ifindex;
816 u8 tos = RT_TOS(iph->tos);
817 u8 prot = iph->protocol;
818 u32 mark = skb->mark;
820 rt = (struct rtable *) dst;
822 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
823 __ip_do_redirect(rt, skb, &fl4, true);
826 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
828 struct rtable *rt = (struct rtable *)dst;
829 struct dst_entry *ret = dst;
832 if (dst->obsolete > 0) {
835 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
846 * 1. The first ip_rt_redirect_number redirects are sent
847 * with exponential backoff, then we stop sending them at all,
848 * assuming that the host ignores our redirects.
849 * 2. If we did not see packets requiring redirects
850 * during ip_rt_redirect_silence, we assume that the host
851 * forgot redirected route and start to send redirects again.
853 * This algorithm is much cheaper and more intelligent than dumb load limiting
856 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
857 * and "frag. need" (breaks PMTU discovery) in icmp.c.
860 void ip_rt_send_redirect(struct sk_buff *skb)
862 struct rtable *rt = skb_rtable(skb);
863 struct in_device *in_dev;
864 struct inet_peer *peer;
870 in_dev = __in_dev_get_rcu(rt->dst.dev);
871 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
875 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
876 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
879 net = dev_net(rt->dst.dev);
880 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
882 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
883 rt_nexthop(rt, ip_hdr(skb)->daddr));
887 /* No redirected packets during ip_rt_redirect_silence;
888 * reset the algorithm.
890 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
891 peer->rate_tokens = 0;
893 /* Too many ignored redirects; do not send anything
894 * set dst.rate_last to the last seen redirected packet.
896 if (peer->rate_tokens >= ip_rt_redirect_number) {
897 peer->rate_last = jiffies;
901 /* Check for load limit; set rate_last to the latest sent
904 if (peer->rate_tokens == 0 ||
907 (ip_rt_redirect_load << peer->rate_tokens)))) {
908 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
910 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
911 peer->rate_last = jiffies;
913 #ifdef CONFIG_IP_ROUTE_VERBOSE
915 peer->rate_tokens == ip_rt_redirect_number)
916 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
917 &ip_hdr(skb)->saddr, inet_iif(skb),
918 &ip_hdr(skb)->daddr, &gw);
925 static int ip_error(struct sk_buff *skb)
927 struct rtable *rt = skb_rtable(skb);
928 struct net_device *dev = skb->dev;
929 struct in_device *in_dev;
930 struct inet_peer *peer;
936 if (netif_is_l3_master(skb->dev)) {
937 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
942 in_dev = __in_dev_get_rcu(dev);
944 /* IP on this device is disabled. */
948 net = dev_net(rt->dst.dev);
949 if (!IN_DEV_FORWARD(in_dev)) {
950 switch (rt->dst.error) {
952 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
956 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
962 switch (rt->dst.error) {
967 code = ICMP_HOST_UNREACH;
970 code = ICMP_NET_UNREACH;
971 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
974 code = ICMP_PKT_FILTERED;
978 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
979 l3mdev_master_ifindex(skb->dev), 1);
984 peer->rate_tokens += now - peer->rate_last;
985 if (peer->rate_tokens > ip_rt_error_burst)
986 peer->rate_tokens = ip_rt_error_burst;
987 peer->rate_last = now;
988 if (peer->rate_tokens >= ip_rt_error_cost)
989 peer->rate_tokens -= ip_rt_error_cost;
995 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1001 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1003 struct dst_entry *dst = &rt->dst;
1004 struct fib_result res;
1007 if (ip_mtu_locked(dst))
1010 if (ipv4_mtu(dst) < mtu)
1013 if (mtu < ip_rt_min_pmtu) {
1015 mtu = ip_rt_min_pmtu;
1018 if (rt->rt_pmtu == mtu &&
1019 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1023 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1024 struct fib_nh *nh = &FIB_RES_NH(res);
1026 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock,
1027 jiffies + ip_rt_mtu_expires);
1032 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1033 struct sk_buff *skb, u32 mtu)
1035 struct rtable *rt = (struct rtable *) dst;
1038 ip_rt_build_flow_key(&fl4, sk, skb);
1039 __ip_rt_update_pmtu(rt, &fl4, mtu);
1042 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1043 int oif, u32 mark, u8 protocol, int flow_flags)
1045 const struct iphdr *iph = (const struct iphdr *) skb->data;
1050 mark = IP4_REPLY_MARK(net, skb->mark);
1052 __build_flow_key(net, &fl4, NULL, iph, oif,
1053 RT_TOS(iph->tos), protocol, mark, flow_flags);
1054 rt = __ip_route_output_key(net, &fl4);
1056 __ip_rt_update_pmtu(rt, &fl4, mtu);
1060 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1062 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1064 const struct iphdr *iph = (const struct iphdr *) skb->data;
1068 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1070 if (!fl4.flowi4_mark)
1071 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1073 rt = __ip_route_output_key(sock_net(sk), &fl4);
1075 __ip_rt_update_pmtu(rt, &fl4, mtu);
1080 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1082 const struct iphdr *iph = (const struct iphdr *) skb->data;
1085 struct dst_entry *odst = NULL;
1087 struct net *net = sock_net(sk);
1091 if (!ip_sk_accept_pmtu(sk))
1094 odst = sk_dst_get(sk);
1096 if (sock_owned_by_user(sk) || !odst) {
1097 __ipv4_sk_update_pmtu(skb, sk, mtu);
1101 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1103 rt = (struct rtable *)odst;
1104 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1105 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1112 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1114 if (!dst_check(&rt->dst, 0)) {
1116 dst_release(&rt->dst);
1118 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1126 sk_dst_set(sk, &rt->dst);
1132 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1134 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1135 int oif, u32 mark, u8 protocol, int flow_flags)
1137 const struct iphdr *iph = (const struct iphdr *) skb->data;
1141 __build_flow_key(net, &fl4, NULL, iph, oif,
1142 RT_TOS(iph->tos), protocol, mark, flow_flags);
1143 rt = __ip_route_output_key(net, &fl4);
1145 __ip_do_redirect(rt, skb, &fl4, false);
1149 EXPORT_SYMBOL_GPL(ipv4_redirect);
1151 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1153 const struct iphdr *iph = (const struct iphdr *) skb->data;
1156 struct net *net = sock_net(sk);
1158 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1159 rt = __ip_route_output_key(net, &fl4);
1161 __ip_do_redirect(rt, skb, &fl4, false);
1165 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1167 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1169 struct rtable *rt = (struct rtable *) dst;
1171 /* All IPV4 dsts are created with ->obsolete set to the value
1172 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1173 * into this function always.
1175 * When a PMTU/redirect information update invalidates a route,
1176 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1177 * DST_OBSOLETE_DEAD by dst_free().
1179 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1184 static void ipv4_link_failure(struct sk_buff *skb)
1188 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1190 rt = skb_rtable(skb);
1192 dst_set_expires(&rt->dst, 0);
1195 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1197 pr_debug("%s: %pI4 -> %pI4, %s\n",
1198 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1199 skb->dev ? skb->dev->name : "?");
1206 We do not cache source address of outgoing interface,
1207 because it is used only by IP RR, TS and SRR options,
1208 so that it out of fast path.
1210 BTW remember: "addr" is allowed to be not aligned
1214 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1218 if (rt_is_output_route(rt))
1219 src = ip_hdr(skb)->saddr;
1221 struct fib_result res;
1227 memset(&fl4, 0, sizeof(fl4));
1228 fl4.daddr = iph->daddr;
1229 fl4.saddr = iph->saddr;
1230 fl4.flowi4_tos = RT_TOS(iph->tos);
1231 fl4.flowi4_oif = rt->dst.dev->ifindex;
1232 fl4.flowi4_iif = skb->dev->ifindex;
1233 fl4.flowi4_mark = skb->mark;
1236 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1237 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1239 src = inet_select_addr(rt->dst.dev,
1240 rt_nexthop(rt, iph->daddr),
1244 memcpy(addr, &src, 4);
1247 #ifdef CONFIG_IP_ROUTE_CLASSID
1248 static void set_class_tag(struct rtable *rt, u32 tag)
1250 if (!(rt->dst.tclassid & 0xFFFF))
1251 rt->dst.tclassid |= tag & 0xFFFF;
1252 if (!(rt->dst.tclassid & 0xFFFF0000))
1253 rt->dst.tclassid |= tag & 0xFFFF0000;
1257 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1259 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1260 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1263 return min(advmss, IPV4_MAX_PMTU - header_size);
1266 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1268 const struct rtable *rt = (const struct rtable *) dst;
1269 unsigned int mtu = rt->rt_pmtu;
1271 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1272 mtu = dst_metric_raw(dst, RTAX_MTU);
1277 mtu = READ_ONCE(dst->dev->mtu);
1279 if (unlikely(ip_mtu_locked(dst))) {
1280 if (rt->rt_uses_gateway && mtu > 576)
1284 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1286 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1289 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1291 struct fnhe_hash_bucket *hash;
1292 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1293 u32 hval = fnhe_hashfun(daddr);
1295 spin_lock_bh(&fnhe_lock);
1297 hash = rcu_dereference_protected(nh->nh_exceptions,
1298 lockdep_is_held(&fnhe_lock));
1301 fnhe_p = &hash->chain;
1302 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1304 if (fnhe->fnhe_daddr == daddr) {
1305 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1306 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1307 fnhe_flush_routes(fnhe);
1308 kfree_rcu(fnhe, rcu);
1311 fnhe_p = &fnhe->fnhe_next;
1312 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1313 lockdep_is_held(&fnhe_lock));
1316 spin_unlock_bh(&fnhe_lock);
1319 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1321 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1322 struct fib_nh_exception *fnhe;
1328 hval = fnhe_hashfun(daddr);
1330 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1331 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1332 if (fnhe->fnhe_daddr == daddr) {
1333 if (fnhe->fnhe_expires &&
1334 time_after(jiffies, fnhe->fnhe_expires)) {
1335 ip_del_fnhe(nh, daddr);
1345 * 1. mtu on route is locked - use it
1346 * 2. mtu from nexthop exception
1347 * 3. mtu from egress device
1350 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1352 struct fib_info *fi = res->fi;
1353 struct fib_nh *nh = &fi->fib_nh[res->nh_sel];
1354 struct net_device *dev = nh->nh_dev;
1357 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1358 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1362 struct fib_nh_exception *fnhe;
1364 fnhe = find_exception(nh, daddr);
1365 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1366 mtu = fnhe->fnhe_pmtu;
1370 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1372 return mtu - lwtunnel_headroom(nh->nh_lwtstate, mtu);
1375 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1376 __be32 daddr, const bool do_cache)
1380 spin_lock_bh(&fnhe_lock);
1382 if (daddr == fnhe->fnhe_daddr) {
1383 struct rtable __rcu **porig;
1384 struct rtable *orig;
1385 int genid = fnhe_genid(dev_net(rt->dst.dev));
1387 if (rt_is_input_route(rt))
1388 porig = &fnhe->fnhe_rth_input;
1390 porig = &fnhe->fnhe_rth_output;
1391 orig = rcu_dereference(*porig);
1393 if (fnhe->fnhe_genid != genid) {
1394 fnhe->fnhe_genid = genid;
1396 fnhe->fnhe_pmtu = 0;
1397 fnhe->fnhe_expires = 0;
1398 fnhe->fnhe_mtu_locked = false;
1399 fnhe_flush_routes(fnhe);
1402 fill_route_from_fnhe(rt, fnhe);
1403 if (!rt->rt_gateway)
1404 rt->rt_gateway = daddr;
1408 rcu_assign_pointer(*porig, rt);
1410 dst_dev_put(&orig->dst);
1411 dst_release(&orig->dst);
1416 fnhe->fnhe_stamp = jiffies;
1418 spin_unlock_bh(&fnhe_lock);
1423 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1425 struct rtable *orig, *prev, **p;
1428 if (rt_is_input_route(rt)) {
1429 p = (struct rtable **)&nh->nh_rth_input;
1431 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1435 /* hold dst before doing cmpxchg() to avoid race condition
1439 prev = cmpxchg(p, orig, rt);
1442 dst_dev_put(&orig->dst);
1443 dst_release(&orig->dst);
1446 dst_release(&rt->dst);
1453 struct uncached_list {
1455 struct list_head head;
1458 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1460 void rt_add_uncached_list(struct rtable *rt)
1462 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1464 rt->rt_uncached_list = ul;
1466 spin_lock_bh(&ul->lock);
1467 list_add_tail(&rt->rt_uncached, &ul->head);
1468 spin_unlock_bh(&ul->lock);
1471 void rt_del_uncached_list(struct rtable *rt)
1473 if (!list_empty(&rt->rt_uncached)) {
1474 struct uncached_list *ul = rt->rt_uncached_list;
1476 spin_lock_bh(&ul->lock);
1477 list_del(&rt->rt_uncached);
1478 spin_unlock_bh(&ul->lock);
1482 static void ipv4_dst_destroy(struct dst_entry *dst)
1484 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1485 struct rtable *rt = (struct rtable *)dst;
1487 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
1490 rt_del_uncached_list(rt);
1493 void rt_flush_dev(struct net_device *dev)
1495 struct net *net = dev_net(dev);
1499 for_each_possible_cpu(cpu) {
1500 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1502 spin_lock_bh(&ul->lock);
1503 list_for_each_entry(rt, &ul->head, rt_uncached) {
1504 if (rt->dst.dev != dev)
1506 rt->dst.dev = net->loopback_dev;
1507 dev_hold(rt->dst.dev);
1510 spin_unlock_bh(&ul->lock);
1514 static bool rt_cache_valid(const struct rtable *rt)
1517 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1521 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1522 const struct fib_result *res,
1523 struct fib_nh_exception *fnhe,
1524 struct fib_info *fi, u16 type, u32 itag,
1525 const bool do_cache)
1527 bool cached = false;
1530 struct fib_nh *nh = &FIB_RES_NH(*res);
1532 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1533 rt->rt_gateway = nh->nh_gw;
1534 rt->rt_uses_gateway = 1;
1536 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1537 if (fi->fib_metrics != &dst_default_metrics) {
1538 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1539 refcount_inc(&fi->fib_metrics->refcnt);
1541 #ifdef CONFIG_IP_ROUTE_CLASSID
1542 rt->dst.tclassid = nh->nh_tclassid;
1544 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1546 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1548 cached = rt_cache_route(nh, rt);
1549 if (unlikely(!cached)) {
1550 /* Routes we intend to cache in nexthop exception or
1551 * FIB nexthop have the DST_NOCACHE bit clear.
1552 * However, if we are unsuccessful at storing this
1553 * route into the cache we really need to set it.
1555 if (!rt->rt_gateway)
1556 rt->rt_gateway = daddr;
1557 rt_add_uncached_list(rt);
1560 rt_add_uncached_list(rt);
1562 #ifdef CONFIG_IP_ROUTE_CLASSID
1563 #ifdef CONFIG_IP_MULTIPLE_TABLES
1564 set_class_tag(rt, res->tclassid);
1566 set_class_tag(rt, itag);
1570 struct rtable *rt_dst_alloc(struct net_device *dev,
1571 unsigned int flags, u16 type,
1572 bool nopolicy, bool noxfrm, bool will_cache)
1576 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1577 (will_cache ? 0 : DST_HOST) |
1578 (nopolicy ? DST_NOPOLICY : 0) |
1579 (noxfrm ? DST_NOXFRM : 0));
1582 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1583 rt->rt_flags = flags;
1585 rt->rt_is_input = 0;
1588 rt->rt_mtu_locked = 0;
1590 rt->rt_uses_gateway = 0;
1591 INIT_LIST_HEAD(&rt->rt_uncached);
1593 rt->dst.output = ip_output;
1594 if (flags & RTCF_LOCAL)
1595 rt->dst.input = ip_local_deliver;
1600 EXPORT_SYMBOL(rt_dst_alloc);
1602 /* called in rcu_read_lock() section */
1603 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1604 u8 tos, struct net_device *dev,
1605 struct in_device *in_dev, u32 *itag)
1609 /* Primary sanity checks. */
1613 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1614 skb->protocol != htons(ETH_P_IP))
1617 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1620 if (ipv4_is_zeronet(saddr)) {
1621 if (!ipv4_is_local_multicast(daddr))
1624 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1632 /* called in rcu_read_lock() section */
1633 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1634 u8 tos, struct net_device *dev, int our)
1636 struct in_device *in_dev = __in_dev_get_rcu(dev);
1637 unsigned int flags = RTCF_MULTICAST;
1642 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1647 flags |= RTCF_LOCAL;
1649 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1650 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1654 #ifdef CONFIG_IP_ROUTE_CLASSID
1655 rth->dst.tclassid = itag;
1657 rth->dst.output = ip_rt_bug;
1658 rth->rt_is_input= 1;
1660 #ifdef CONFIG_IP_MROUTE
1661 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1662 rth->dst.input = ip_mr_input;
1664 RT_CACHE_STAT_INC(in_slow_mc);
1666 skb_dst_set(skb, &rth->dst);
1671 static void ip_handle_martian_source(struct net_device *dev,
1672 struct in_device *in_dev,
1673 struct sk_buff *skb,
1677 RT_CACHE_STAT_INC(in_martian_src);
1678 #ifdef CONFIG_IP_ROUTE_VERBOSE
1679 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1681 * RFC1812 recommendation, if source is martian,
1682 * the only hint is MAC header.
1684 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1685 &daddr, &saddr, dev->name);
1686 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1687 print_hex_dump(KERN_WARNING, "ll header: ",
1688 DUMP_PREFIX_OFFSET, 16, 1,
1689 skb_mac_header(skb),
1690 dev->hard_header_len, true);
1696 /* called in rcu_read_lock() section */
1697 static int __mkroute_input(struct sk_buff *skb,
1698 const struct fib_result *res,
1699 struct in_device *in_dev,
1700 __be32 daddr, __be32 saddr, u32 tos)
1702 struct fib_nh_exception *fnhe;
1705 struct in_device *out_dev;
1709 /* get a working reference to the output device */
1710 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1712 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1716 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1717 in_dev->dev, in_dev, &itag);
1719 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1725 do_cache = res->fi && !itag;
1726 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1727 skb->protocol == htons(ETH_P_IP) &&
1728 (IN_DEV_SHARED_MEDIA(out_dev) ||
1729 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1730 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1732 if (skb->protocol != htons(ETH_P_IP)) {
1733 /* Not IP (i.e. ARP). Do not create route, if it is
1734 * invalid for proxy arp. DNAT routes are always valid.
1736 * Proxy arp feature have been extended to allow, ARP
1737 * replies back to the same interface, to support
1738 * Private VLAN switch technologies. See arp.c.
1740 if (out_dev == in_dev &&
1741 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1747 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1750 rth = rcu_dereference(fnhe->fnhe_rth_input);
1752 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1753 if (rt_cache_valid(rth)) {
1754 skb_dst_set_noref(skb, &rth->dst);
1759 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1760 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1761 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1767 rth->rt_is_input = 1;
1768 RT_CACHE_STAT_INC(in_slow_tot);
1770 rth->dst.input = ip_forward;
1772 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1774 lwtunnel_set_redirect(&rth->dst);
1775 skb_dst_set(skb, &rth->dst);
1782 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1783 /* To make ICMP packets follow the right flow, the multipath hash is
1784 * calculated from the inner IP addresses.
1786 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1787 struct flow_keys *hash_keys)
1789 const struct iphdr *outer_iph = ip_hdr(skb);
1790 const struct iphdr *key_iph = outer_iph;
1791 const struct iphdr *inner_iph;
1792 const struct icmphdr *icmph;
1793 struct iphdr _inner_iph;
1794 struct icmphdr _icmph;
1796 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1799 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1802 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1807 if (icmph->type != ICMP_DEST_UNREACH &&
1808 icmph->type != ICMP_REDIRECT &&
1809 icmph->type != ICMP_TIME_EXCEEDED &&
1810 icmph->type != ICMP_PARAMETERPROB)
1813 inner_iph = skb_header_pointer(skb,
1814 outer_iph->ihl * 4 + sizeof(_icmph),
1815 sizeof(_inner_iph), &_inner_iph);
1819 key_iph = inner_iph;
1821 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1822 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1825 /* if skb is set it will be used and fl4 can be NULL */
1826 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1827 const struct sk_buff *skb, struct flow_keys *flkeys)
1829 struct flow_keys hash_keys;
1832 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1834 memset(&hash_keys, 0, sizeof(hash_keys));
1835 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1837 ip_multipath_l3_keys(skb, &hash_keys);
1839 hash_keys.addrs.v4addrs.src = fl4->saddr;
1840 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1844 /* skb is currently provided only when forwarding */
1846 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1847 struct flow_keys keys;
1849 /* short-circuit if we already have L4 hash present */
1851 return skb_get_hash_raw(skb) >> 1;
1853 memset(&hash_keys, 0, sizeof(hash_keys));
1856 skb_flow_dissect_flow_keys(skb, &keys, flag);
1860 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1861 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1862 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1863 hash_keys.ports.src = flkeys->ports.src;
1864 hash_keys.ports.dst = flkeys->ports.dst;
1865 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1867 memset(&hash_keys, 0, sizeof(hash_keys));
1868 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1869 hash_keys.addrs.v4addrs.src = fl4->saddr;
1870 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1871 hash_keys.ports.src = fl4->fl4_sport;
1872 hash_keys.ports.dst = fl4->fl4_dport;
1873 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1877 mhash = flow_hash_from_keys(&hash_keys);
1881 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1883 static int ip_mkroute_input(struct sk_buff *skb,
1884 struct fib_result *res,
1885 struct in_device *in_dev,
1886 __be32 daddr, __be32 saddr, u32 tos,
1887 struct flow_keys *hkeys)
1889 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1890 if (res->fi && res->fi->fib_nhs > 1) {
1891 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
1893 fib_select_multipath(res, h);
1897 /* create a routing cache entry */
1898 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1902 * NOTE. We drop all the packets that has local source
1903 * addresses, because every properly looped back packet
1904 * must have correct destination already attached by output routine.
1906 * Such approach solves two big problems:
1907 * 1. Not simplex devices are handled properly.
1908 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1909 * called with rcu_read_lock()
1912 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1913 u8 tos, struct net_device *dev,
1914 struct fib_result *res)
1916 struct in_device *in_dev = __in_dev_get_rcu(dev);
1917 struct flow_keys *flkeys = NULL, _flkeys;
1918 struct net *net = dev_net(dev);
1919 struct ip_tunnel_info *tun_info;
1921 unsigned int flags = 0;
1927 /* IP on this device is disabled. */
1932 /* Check for the most weird martians, which can be not detected
1936 tun_info = skb_tunnel_info(skb);
1937 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1938 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1940 fl4.flowi4_tun_key.tun_id = 0;
1943 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1944 goto martian_source;
1948 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1951 /* Accept zero addresses only to limited broadcast;
1952 * I even do not know to fix it or not. Waiting for complains :-)
1954 if (ipv4_is_zeronet(saddr))
1955 goto martian_source;
1957 if (ipv4_is_zeronet(daddr))
1958 goto martian_destination;
1960 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1961 * and call it once if daddr or/and saddr are loopback addresses
1963 if (ipv4_is_loopback(daddr)) {
1964 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1965 goto martian_destination;
1966 } else if (ipv4_is_loopback(saddr)) {
1967 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1968 goto martian_source;
1972 * Now we are ready to route packet.
1975 fl4.flowi4_iif = dev->ifindex;
1976 fl4.flowi4_mark = skb->mark;
1977 fl4.flowi4_tos = tos;
1978 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1979 fl4.flowi4_flags = 0;
1982 fl4.flowi4_uid = sock_net_uid(net, NULL);
1984 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
1987 fl4.flowi4_proto = 0;
1992 err = fib_lookup(net, &fl4, res, 0);
1994 if (!IN_DEV_FORWARD(in_dev))
1995 err = -EHOSTUNREACH;
1999 if (res->type == RTN_BROADCAST) {
2000 if (IN_DEV_BFORWARD(in_dev))
2005 if (res->type == RTN_LOCAL) {
2006 err = fib_validate_source(skb, saddr, daddr, tos,
2007 0, dev, in_dev, &itag);
2009 goto martian_source;
2013 if (!IN_DEV_FORWARD(in_dev)) {
2014 err = -EHOSTUNREACH;
2017 if (res->type != RTN_UNICAST)
2018 goto martian_destination;
2021 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2025 if (skb->protocol != htons(ETH_P_IP))
2028 if (!ipv4_is_zeronet(saddr)) {
2029 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2032 goto martian_source;
2034 flags |= RTCF_BROADCAST;
2035 res->type = RTN_BROADCAST;
2036 RT_CACHE_STAT_INC(in_brd);
2042 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2043 if (rt_cache_valid(rth)) {
2044 skb_dst_set_noref(skb, &rth->dst);
2052 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2053 flags | RTCF_LOCAL, res->type,
2054 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2058 rth->dst.output= ip_rt_bug;
2059 #ifdef CONFIG_IP_ROUTE_CLASSID
2060 rth->dst.tclassid = itag;
2062 rth->rt_is_input = 1;
2064 RT_CACHE_STAT_INC(in_slow_tot);
2065 if (res->type == RTN_UNREACHABLE) {
2066 rth->dst.input= ip_error;
2067 rth->dst.error= -err;
2068 rth->rt_flags &= ~RTCF_LOCAL;
2072 struct fib_nh *nh = &FIB_RES_NH(*res);
2074 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2075 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2076 WARN_ON(rth->dst.input == lwtunnel_input);
2077 rth->dst.lwtstate->orig_input = rth->dst.input;
2078 rth->dst.input = lwtunnel_input;
2081 if (unlikely(!rt_cache_route(nh, rth)))
2082 rt_add_uncached_list(rth);
2084 skb_dst_set(skb, &rth->dst);
2089 RT_CACHE_STAT_INC(in_no_route);
2090 res->type = RTN_UNREACHABLE;
2096 * Do not cache martian addresses: they should be logged (RFC1812)
2098 martian_destination:
2099 RT_CACHE_STAT_INC(in_martian_dst);
2100 #ifdef CONFIG_IP_ROUTE_VERBOSE
2101 if (IN_DEV_LOG_MARTIANS(in_dev))
2102 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2103 &daddr, &saddr, dev->name);
2115 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2119 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2120 u8 tos, struct net_device *dev)
2122 struct fib_result res;
2125 tos &= IPTOS_RT_MASK;
2127 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2132 EXPORT_SYMBOL(ip_route_input_noref);
2134 /* called with rcu_read_lock held */
2135 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2136 u8 tos, struct net_device *dev, struct fib_result *res)
2138 /* Multicast recognition logic is moved from route cache to here.
2139 The problem was that too many Ethernet cards have broken/missing
2140 hardware multicast filters :-( As result the host on multicasting
2141 network acquires a lot of useless route cache entries, sort of
2142 SDR messages from all the world. Now we try to get rid of them.
2143 Really, provided software IP multicast filter is organized
2144 reasonably (at least, hashed), it does not result in a slowdown
2145 comparing with route cache reject entries.
2146 Note, that multicast routers are not affected, because
2147 route cache entry is created eventually.
2149 if (ipv4_is_multicast(daddr)) {
2150 struct in_device *in_dev = __in_dev_get_rcu(dev);
2155 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2156 ip_hdr(skb)->protocol);
2158 /* check l3 master if no match yet */
2159 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2160 struct in_device *l3_in_dev;
2162 l3_in_dev = __in_dev_get_rcu(skb->dev);
2164 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2165 ip_hdr(skb)->protocol);
2169 #ifdef CONFIG_IP_MROUTE
2171 (!ipv4_is_local_multicast(daddr) &&
2172 IN_DEV_MFORWARD(in_dev))
2175 err = ip_route_input_mc(skb, daddr, saddr,
2181 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2184 /* called with rcu_read_lock() */
2185 static struct rtable *__mkroute_output(const struct fib_result *res,
2186 const struct flowi4 *fl4, int orig_oif,
2187 struct net_device *dev_out,
2190 struct fib_info *fi = res->fi;
2191 struct fib_nh_exception *fnhe;
2192 struct in_device *in_dev;
2193 u16 type = res->type;
2197 in_dev = __in_dev_get_rcu(dev_out);
2199 return ERR_PTR(-EINVAL);
2201 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2202 if (ipv4_is_loopback(fl4->saddr) &&
2203 !(dev_out->flags & IFF_LOOPBACK) &&
2204 !netif_is_l3_master(dev_out))
2205 return ERR_PTR(-EINVAL);
2207 if (ipv4_is_lbcast(fl4->daddr))
2208 type = RTN_BROADCAST;
2209 else if (ipv4_is_multicast(fl4->daddr))
2210 type = RTN_MULTICAST;
2211 else if (ipv4_is_zeronet(fl4->daddr))
2212 return ERR_PTR(-EINVAL);
2214 if (dev_out->flags & IFF_LOOPBACK)
2215 flags |= RTCF_LOCAL;
2218 if (type == RTN_BROADCAST) {
2219 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2221 } else if (type == RTN_MULTICAST) {
2222 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2223 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2225 flags &= ~RTCF_LOCAL;
2228 /* If multicast route do not exist use
2229 * default one, but do not gateway in this case.
2232 if (fi && res->prefixlen < 4)
2234 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2235 (orig_oif != dev_out->ifindex)) {
2236 /* For local routes that require a particular output interface
2237 * we do not want to cache the result. Caching the result
2238 * causes incorrect behaviour when there are multiple source
2239 * addresses on the interface, the end result being that if the
2240 * intended recipient is waiting on that interface for the
2241 * packet he won't receive it because it will be delivered on
2242 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2243 * be set to the loopback interface as well.
2249 do_cache &= fi != NULL;
2251 struct rtable __rcu **prth;
2252 struct fib_nh *nh = &FIB_RES_NH(*res);
2254 fnhe = find_exception(nh, fl4->daddr);
2258 prth = &fnhe->fnhe_rth_output;
2260 if (unlikely(fl4->flowi4_flags &
2261 FLOWI_FLAG_KNOWN_NH &&
2263 nh->nh_scope == RT_SCOPE_LINK))) {
2267 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2269 rth = rcu_dereference(*prth);
2270 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2275 rth = rt_dst_alloc(dev_out, flags, type,
2276 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2277 IN_DEV_CONF_GET(in_dev, NOXFRM),
2280 return ERR_PTR(-ENOBUFS);
2282 rth->rt_iif = orig_oif;
2284 RT_CACHE_STAT_INC(out_slow_tot);
2286 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2287 if (flags & RTCF_LOCAL &&
2288 !(dev_out->flags & IFF_LOOPBACK)) {
2289 rth->dst.output = ip_mc_output;
2290 RT_CACHE_STAT_INC(out_slow_mc);
2292 #ifdef CONFIG_IP_MROUTE
2293 if (type == RTN_MULTICAST) {
2294 if (IN_DEV_MFORWARD(in_dev) &&
2295 !ipv4_is_local_multicast(fl4->daddr)) {
2296 rth->dst.input = ip_mr_input;
2297 rth->dst.output = ip_mc_output;
2303 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2304 lwtunnel_set_redirect(&rth->dst);
2310 * Major route resolver routine.
2313 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2314 const struct sk_buff *skb)
2316 __u8 tos = RT_FL_TOS(fl4);
2317 struct fib_result res = {
2325 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2326 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2327 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2328 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2331 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2336 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2338 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2339 struct fib_result *res,
2340 const struct sk_buff *skb)
2342 struct net_device *dev_out = NULL;
2343 int orig_oif = fl4->flowi4_oif;
2344 unsigned int flags = 0;
2346 int err = -ENETUNREACH;
2349 rth = ERR_PTR(-EINVAL);
2350 if (ipv4_is_multicast(fl4->saddr) ||
2351 ipv4_is_lbcast(fl4->saddr) ||
2352 ipv4_is_zeronet(fl4->saddr))
2355 /* I removed check for oif == dev_out->oif here.
2356 It was wrong for two reasons:
2357 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2358 is assigned to multiple interfaces.
2359 2. Moreover, we are allowed to send packets with saddr
2360 of another iface. --ANK
2363 if (fl4->flowi4_oif == 0 &&
2364 (ipv4_is_multicast(fl4->daddr) ||
2365 ipv4_is_lbcast(fl4->daddr))) {
2366 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2367 dev_out = __ip_dev_find(net, fl4->saddr, false);
2371 /* Special hack: user can direct multicasts
2372 and limited broadcast via necessary interface
2373 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2374 This hack is not just for fun, it allows
2375 vic,vat and friends to work.
2376 They bind socket to loopback, set ttl to zero
2377 and expect that it will work.
2378 From the viewpoint of routing cache they are broken,
2379 because we are not allowed to build multicast path
2380 with loopback source addr (look, routing cache
2381 cannot know, that ttl is zero, so that packet
2382 will not leave this host and route is valid).
2383 Luckily, this hack is good workaround.
2386 fl4->flowi4_oif = dev_out->ifindex;
2390 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2391 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2392 if (!__ip_dev_find(net, fl4->saddr, false))
2398 if (fl4->flowi4_oif) {
2399 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2400 rth = ERR_PTR(-ENODEV);
2404 /* RACE: Check return value of inet_select_addr instead. */
2405 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2406 rth = ERR_PTR(-ENETUNREACH);
2409 if (ipv4_is_local_multicast(fl4->daddr) ||
2410 ipv4_is_lbcast(fl4->daddr) ||
2411 fl4->flowi4_proto == IPPROTO_IGMP) {
2413 fl4->saddr = inet_select_addr(dev_out, 0,
2418 if (ipv4_is_multicast(fl4->daddr))
2419 fl4->saddr = inet_select_addr(dev_out, 0,
2421 else if (!fl4->daddr)
2422 fl4->saddr = inet_select_addr(dev_out, 0,
2428 fl4->daddr = fl4->saddr;
2430 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2431 dev_out = net->loopback_dev;
2432 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2433 res->type = RTN_LOCAL;
2434 flags |= RTCF_LOCAL;
2438 err = fib_lookup(net, fl4, res, 0);
2442 if (fl4->flowi4_oif &&
2443 (ipv4_is_multicast(fl4->daddr) ||
2444 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2445 /* Apparently, routing tables are wrong. Assume,
2446 that the destination is on link.
2449 Because we are allowed to send to iface
2450 even if it has NO routes and NO assigned
2451 addresses. When oif is specified, routing
2452 tables are looked up with only one purpose:
2453 to catch if destination is gatewayed, rather than
2454 direct. Moreover, if MSG_DONTROUTE is set,
2455 we send packet, ignoring both routing tables
2456 and ifaddr state. --ANK
2459 We could make it even if oif is unknown,
2460 likely IPv6, but we do not.
2463 if (fl4->saddr == 0)
2464 fl4->saddr = inet_select_addr(dev_out, 0,
2466 res->type = RTN_UNICAST;
2473 if (res->type == RTN_LOCAL) {
2475 if (res->fi->fib_prefsrc)
2476 fl4->saddr = res->fi->fib_prefsrc;
2478 fl4->saddr = fl4->daddr;
2481 /* L3 master device is the loopback for that domain */
2482 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2485 /* make sure orig_oif points to fib result device even
2486 * though packet rx/tx happens over loopback or l3mdev
2488 orig_oif = FIB_RES_OIF(*res);
2490 fl4->flowi4_oif = dev_out->ifindex;
2491 flags |= RTCF_LOCAL;
2495 fib_select_path(net, res, fl4, skb);
2497 dev_out = FIB_RES_DEV(*res);
2498 fl4->flowi4_oif = dev_out->ifindex;
2502 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2508 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2513 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2515 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2517 return mtu ? : dst->dev->mtu;
2520 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2521 struct sk_buff *skb, u32 mtu)
2525 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2526 struct sk_buff *skb)
2530 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2536 static struct dst_ops ipv4_dst_blackhole_ops = {
2538 .check = ipv4_blackhole_dst_check,
2539 .mtu = ipv4_blackhole_mtu,
2540 .default_advmss = ipv4_default_advmss,
2541 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2542 .redirect = ipv4_rt_blackhole_redirect,
2543 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2544 .neigh_lookup = ipv4_neigh_lookup,
2547 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2549 struct rtable *ort = (struct rtable *) dst_orig;
2552 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2554 struct dst_entry *new = &rt->dst;
2557 new->input = dst_discard;
2558 new->output = dst_discard_out;
2560 new->dev = net->loopback_dev;
2564 rt->rt_is_input = ort->rt_is_input;
2565 rt->rt_iif = ort->rt_iif;
2566 rt->rt_pmtu = ort->rt_pmtu;
2567 rt->rt_mtu_locked = ort->rt_mtu_locked;
2569 rt->rt_genid = rt_genid_ipv4(net);
2570 rt->rt_flags = ort->rt_flags;
2571 rt->rt_type = ort->rt_type;
2572 rt->rt_gateway = ort->rt_gateway;
2573 rt->rt_uses_gateway = ort->rt_uses_gateway;
2575 INIT_LIST_HEAD(&rt->rt_uncached);
2578 dst_release(dst_orig);
2580 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2583 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2584 const struct sock *sk)
2586 struct rtable *rt = __ip_route_output_key(net, flp4);
2591 if (flp4->flowi4_proto)
2592 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2593 flowi4_to_flowi(flp4),
2598 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2600 /* called with rcu_read_lock held */
2601 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2602 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2603 struct sk_buff *skb, u32 portid, u32 seq)
2606 struct nlmsghdr *nlh;
2607 unsigned long expires = 0;
2609 u32 metrics[RTAX_MAX];
2611 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2615 r = nlmsg_data(nlh);
2616 r->rtm_family = AF_INET;
2617 r->rtm_dst_len = 32;
2619 r->rtm_tos = fl4->flowi4_tos;
2620 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2621 if (nla_put_u32(skb, RTA_TABLE, table_id))
2622 goto nla_put_failure;
2623 r->rtm_type = rt->rt_type;
2624 r->rtm_scope = RT_SCOPE_UNIVERSE;
2625 r->rtm_protocol = RTPROT_UNSPEC;
2626 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2627 if (rt->rt_flags & RTCF_NOTIFY)
2628 r->rtm_flags |= RTM_F_NOTIFY;
2629 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2630 r->rtm_flags |= RTCF_DOREDIRECT;
2632 if (nla_put_in_addr(skb, RTA_DST, dst))
2633 goto nla_put_failure;
2635 r->rtm_src_len = 32;
2636 if (nla_put_in_addr(skb, RTA_SRC, src))
2637 goto nla_put_failure;
2640 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2641 goto nla_put_failure;
2642 #ifdef CONFIG_IP_ROUTE_CLASSID
2643 if (rt->dst.tclassid &&
2644 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2645 goto nla_put_failure;
2647 if (!rt_is_input_route(rt) &&
2648 fl4->saddr != src) {
2649 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2650 goto nla_put_failure;
2652 if (rt->rt_uses_gateway &&
2653 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2654 goto nla_put_failure;
2656 expires = rt->dst.expires;
2658 unsigned long now = jiffies;
2660 if (time_before(now, expires))
2666 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2667 if (rt->rt_pmtu && expires)
2668 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2669 if (rt->rt_mtu_locked && expires)
2670 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2671 if (rtnetlink_put_metrics(skb, metrics) < 0)
2672 goto nla_put_failure;
2674 if (fl4->flowi4_mark &&
2675 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2676 goto nla_put_failure;
2678 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2679 nla_put_u32(skb, RTA_UID,
2680 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2681 goto nla_put_failure;
2683 error = rt->dst.error;
2685 if (rt_is_input_route(rt)) {
2686 #ifdef CONFIG_IP_MROUTE
2687 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2688 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2689 int err = ipmr_get_route(net, skb,
2690 fl4->saddr, fl4->daddr,
2696 goto nla_put_failure;
2700 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2701 goto nla_put_failure;
2704 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2705 goto nla_put_failure;
2707 nlmsg_end(skb, nlh);
2711 nlmsg_cancel(skb, nlh);
2715 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
2716 u8 ip_proto, __be16 sport,
2719 struct sk_buff *skb;
2722 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2726 /* Reserve room for dummy headers, this skb can pass
2727 * through good chunk of routing engine.
2729 skb_reset_mac_header(skb);
2730 skb_reset_network_header(skb);
2731 skb->protocol = htons(ETH_P_IP);
2732 iph = skb_put(skb, sizeof(struct iphdr));
2733 iph->protocol = ip_proto;
2739 skb_set_transport_header(skb, skb->len);
2741 switch (iph->protocol) {
2743 struct udphdr *udph;
2745 udph = skb_put_zero(skb, sizeof(struct udphdr));
2746 udph->source = sport;
2748 udph->len = sizeof(struct udphdr);
2753 struct tcphdr *tcph;
2755 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
2756 tcph->source = sport;
2758 tcph->doff = sizeof(struct tcphdr) / 4;
2760 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
2764 case IPPROTO_ICMP: {
2765 struct icmphdr *icmph;
2767 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
2768 icmph->type = ICMP_ECHO;
2776 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2777 struct netlink_ext_ack *extack)
2779 struct net *net = sock_net(in_skb->sk);
2780 struct nlattr *tb[RTA_MAX+1];
2781 u32 table_id = RT_TABLE_MAIN;
2782 __be16 sport = 0, dport = 0;
2783 struct fib_result res = {};
2784 u8 ip_proto = IPPROTO_UDP;
2785 struct rtable *rt = NULL;
2786 struct sk_buff *skb;
2796 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2801 rtm = nlmsg_data(nlh);
2802 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2803 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2804 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2805 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2807 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2809 uid = (iif ? INVALID_UID : current_uid());
2811 if (tb[RTA_IP_PROTO]) {
2812 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
2819 sport = nla_get_be16(tb[RTA_SPORT]);
2822 dport = nla_get_be16(tb[RTA_DPORT]);
2824 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
2828 memset(&fl4, 0, sizeof(fl4));
2831 fl4.flowi4_tos = rtm->rtm_tos;
2832 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2833 fl4.flowi4_mark = mark;
2834 fl4.flowi4_uid = uid;
2836 fl4.fl4_sport = sport;
2838 fl4.fl4_dport = dport;
2839 fl4.flowi4_proto = ip_proto;
2844 struct net_device *dev;
2846 dev = dev_get_by_index_rcu(net, iif);
2852 fl4.flowi4_iif = iif; /* for rt_fill_info */
2855 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2858 rt = skb_rtable(skb);
2859 if (err == 0 && rt->dst.error)
2860 err = -rt->dst.error;
2862 fl4.flowi4_iif = LOOPBACK_IFINDEX;
2863 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2868 skb_dst_set(skb, &rt->dst);
2874 if (rtm->rtm_flags & RTM_F_NOTIFY)
2875 rt->rt_flags |= RTCF_NOTIFY;
2877 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2878 table_id = res.table ? res.table->tb_id : 0;
2880 /* reset skb for netlink reply msg */
2882 skb_reset_network_header(skb);
2883 skb_reset_transport_header(skb);
2884 skb_reset_mac_header(skb);
2886 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2888 err = fib_props[res.type].error;
2890 err = -EHOSTUNREACH;
2893 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2894 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2895 rt->rt_type, res.prefix, res.prefixlen,
2896 fl4.flowi4_tos, res.fi, 0);
2898 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
2899 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2906 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2916 void ip_rt_multicast_event(struct in_device *in_dev)
2918 rt_cache_flush(dev_net(in_dev->dev));
2921 #ifdef CONFIG_SYSCTL
2922 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2923 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2924 static int ip_rt_gc_elasticity __read_mostly = 8;
2925 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
2927 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2928 void __user *buffer,
2929 size_t *lenp, loff_t *ppos)
2931 struct net *net = (struct net *)__ctl->extra1;
2934 rt_cache_flush(net);
2935 fnhe_genid_bump(net);
2942 static struct ctl_table ipv4_route_table[] = {
2944 .procname = "gc_thresh",
2945 .data = &ipv4_dst_ops.gc_thresh,
2946 .maxlen = sizeof(int),
2948 .proc_handler = proc_dointvec,
2951 .procname = "max_size",
2952 .data = &ip_rt_max_size,
2953 .maxlen = sizeof(int),
2955 .proc_handler = proc_dointvec,
2958 /* Deprecated. Use gc_min_interval_ms */
2960 .procname = "gc_min_interval",
2961 .data = &ip_rt_gc_min_interval,
2962 .maxlen = sizeof(int),
2964 .proc_handler = proc_dointvec_jiffies,
2967 .procname = "gc_min_interval_ms",
2968 .data = &ip_rt_gc_min_interval,
2969 .maxlen = sizeof(int),
2971 .proc_handler = proc_dointvec_ms_jiffies,
2974 .procname = "gc_timeout",
2975 .data = &ip_rt_gc_timeout,
2976 .maxlen = sizeof(int),
2978 .proc_handler = proc_dointvec_jiffies,
2981 .procname = "gc_interval",
2982 .data = &ip_rt_gc_interval,
2983 .maxlen = sizeof(int),
2985 .proc_handler = proc_dointvec_jiffies,
2988 .procname = "redirect_load",
2989 .data = &ip_rt_redirect_load,
2990 .maxlen = sizeof(int),
2992 .proc_handler = proc_dointvec,
2995 .procname = "redirect_number",
2996 .data = &ip_rt_redirect_number,
2997 .maxlen = sizeof(int),
2999 .proc_handler = proc_dointvec,
3002 .procname = "redirect_silence",
3003 .data = &ip_rt_redirect_silence,
3004 .maxlen = sizeof(int),
3006 .proc_handler = proc_dointvec,
3009 .procname = "error_cost",
3010 .data = &ip_rt_error_cost,
3011 .maxlen = sizeof(int),
3013 .proc_handler = proc_dointvec,
3016 .procname = "error_burst",
3017 .data = &ip_rt_error_burst,
3018 .maxlen = sizeof(int),
3020 .proc_handler = proc_dointvec,
3023 .procname = "gc_elasticity",
3024 .data = &ip_rt_gc_elasticity,
3025 .maxlen = sizeof(int),
3027 .proc_handler = proc_dointvec,
3030 .procname = "mtu_expires",
3031 .data = &ip_rt_mtu_expires,
3032 .maxlen = sizeof(int),
3034 .proc_handler = proc_dointvec_jiffies,
3037 .procname = "min_pmtu",
3038 .data = &ip_rt_min_pmtu,
3039 .maxlen = sizeof(int),
3041 .proc_handler = proc_dointvec_minmax,
3042 .extra1 = &ip_min_valid_pmtu,
3045 .procname = "min_adv_mss",
3046 .data = &ip_rt_min_advmss,
3047 .maxlen = sizeof(int),
3049 .proc_handler = proc_dointvec,
3054 static struct ctl_table ipv4_route_flush_table[] = {
3056 .procname = "flush",
3057 .maxlen = sizeof(int),
3059 .proc_handler = ipv4_sysctl_rtcache_flush,
3064 static __net_init int sysctl_route_net_init(struct net *net)
3066 struct ctl_table *tbl;
3068 tbl = ipv4_route_flush_table;
3069 if (!net_eq(net, &init_net)) {
3070 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3074 /* Don't export sysctls to unprivileged users */
3075 if (net->user_ns != &init_user_ns)
3076 tbl[0].procname = NULL;
3078 tbl[0].extra1 = net;
3080 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3081 if (!net->ipv4.route_hdr)
3086 if (tbl != ipv4_route_flush_table)
3092 static __net_exit void sysctl_route_net_exit(struct net *net)
3094 struct ctl_table *tbl;
3096 tbl = net->ipv4.route_hdr->ctl_table_arg;
3097 unregister_net_sysctl_table(net->ipv4.route_hdr);
3098 BUG_ON(tbl == ipv4_route_flush_table);
3102 static __net_initdata struct pernet_operations sysctl_route_ops = {
3103 .init = sysctl_route_net_init,
3104 .exit = sysctl_route_net_exit,
3108 static __net_init int rt_genid_init(struct net *net)
3110 atomic_set(&net->ipv4.rt_genid, 0);
3111 atomic_set(&net->fnhe_genid, 0);
3112 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3116 static __net_initdata struct pernet_operations rt_genid_ops = {
3117 .init = rt_genid_init,
3120 static int __net_init ipv4_inetpeer_init(struct net *net)
3122 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3126 inet_peer_base_init(bp);
3127 net->ipv4.peers = bp;
3131 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3133 struct inet_peer_base *bp = net->ipv4.peers;
3135 net->ipv4.peers = NULL;
3136 inetpeer_invalidate_tree(bp);
3140 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3141 .init = ipv4_inetpeer_init,
3142 .exit = ipv4_inetpeer_exit,
3145 #ifdef CONFIG_IP_ROUTE_CLASSID
3146 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3147 #endif /* CONFIG_IP_ROUTE_CLASSID */
3149 int __init ip_rt_init(void)
3153 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents),
3156 panic("IP: failed to allocate ip_idents\n");
3158 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3160 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3162 panic("IP: failed to allocate ip_tstamps\n");
3164 for_each_possible_cpu(cpu) {
3165 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3167 INIT_LIST_HEAD(&ul->head);
3168 spin_lock_init(&ul->lock);
3170 #ifdef CONFIG_IP_ROUTE_CLASSID
3171 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3173 panic("IP: failed to allocate ip_rt_acct\n");
3176 ipv4_dst_ops.kmem_cachep =
3177 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3178 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3180 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3182 if (dst_entries_init(&ipv4_dst_ops) < 0)
3183 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3185 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3186 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3188 ipv4_dst_ops.gc_thresh = ~0;
3189 ip_rt_max_size = INT_MAX;
3194 if (ip_rt_proc_init())
3195 pr_err("Unable to create route proc files\n");
3200 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3201 RTNL_FLAG_DOIT_UNLOCKED);
3203 #ifdef CONFIG_SYSCTL
3204 register_pernet_subsys(&sysctl_route_ops);
3206 register_pernet_subsys(&rt_genid_ops);
3207 register_pernet_subsys(&ipv4_inetpeer_ops);
3211 #ifdef CONFIG_SYSCTL
3213 * We really need to sanitize the damn ipv4 init order, then all
3214 * this nonsense will go away.
3216 void __init ip_static_sysctl_init(void)
3218 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);