2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * ROUTE - implementation of the IP router.
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
65 #define pr_fmt(fmt) "IPv4: " fmt
67 #include <linux/module.h>
68 #include <asm/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/types.h>
71 #include <linux/kernel.h>
73 #include <linux/bootmem.h>
74 #include <linux/string.h>
75 #include <linux/socket.h>
76 #include <linux/sockios.h>
77 #include <linux/errno.h>
79 #include <linux/inet.h>
80 #include <linux/netdevice.h>
81 #include <linux/proc_fs.h>
82 #include <linux/init.h>
83 #include <linux/workqueue.h>
84 #include <linux/skbuff.h>
85 #include <linux/inetdevice.h>
86 #include <linux/igmp.h>
87 #include <linux/pkt_sched.h>
88 #include <linux/mroute.h>
89 #include <linux/netfilter_ipv4.h>
90 #include <linux/random.h>
91 #include <linux/jhash.h>
92 #include <linux/rcupdate.h>
93 #include <linux/times.h>
94 #include <linux/slab.h>
95 #include <linux/prefetch.h>
97 #include <net/net_namespace.h>
98 #include <net/protocol.h>
100 #include <net/route.h>
101 #include <net/inetpeer.h>
102 #include <net/sock.h>
103 #include <net/ip_fib.h>
106 #include <net/icmp.h>
107 #include <net/xfrm.h>
108 #include <net/netevent.h>
109 #include <net/rtnetlink.h>
111 #include <linux/sysctl.h>
112 #include <linux/kmemleak.h>
114 #include <net/secure_seq.h>
116 #define RT_FL_TOS(oldflp4) \
117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
119 #define IP_MAX_MTU 0xFFF0
121 #define RT_GC_TIMEOUT (300*HZ)
123 static int ip_rt_max_size;
124 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
125 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
126 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
127 static int ip_rt_redirect_number __read_mostly = 9;
128 static int ip_rt_redirect_load __read_mostly = HZ / 50;
129 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
130 static int ip_rt_error_cost __read_mostly = HZ;
131 static int ip_rt_error_burst __read_mostly = 5 * HZ;
132 static int ip_rt_gc_elasticity __read_mostly = 8;
133 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
134 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
135 static int ip_rt_min_advmss __read_mostly = 256;
136 static int rt_chain_length_max __read_mostly = 20;
138 static struct delayed_work expires_work;
139 static unsigned long expires_ljiffies;
142 * Interface to generic destination cache.
145 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
146 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
147 static unsigned int ipv4_mtu(const struct dst_entry *dst);
148 static void ipv4_dst_destroy(struct dst_entry *dst);
149 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
150 static void ipv4_link_failure(struct sk_buff *skb);
151 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
152 static int rt_garbage_collect(struct dst_ops *ops);
154 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
159 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
161 struct rtable *rt = (struct rtable *) dst;
162 struct inet_peer *peer;
165 peer = rt_get_peer_create(rt, rt->rt_dst);
167 u32 *old_p = __DST_METRICS_PTR(old);
168 unsigned long prev, new;
171 if (inet_metrics_new(peer))
172 memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
174 new = (unsigned long) p;
175 prev = cmpxchg(&dst->_metrics, old, new);
178 p = __DST_METRICS_PTR(prev);
179 if (prev & DST_METRICS_READ_ONLY)
183 fib_info_put(rt->fi);
191 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr);
193 static struct dst_ops ipv4_dst_ops = {
195 .protocol = cpu_to_be16(ETH_P_IP),
196 .gc = rt_garbage_collect,
197 .check = ipv4_dst_check,
198 .default_advmss = ipv4_default_advmss,
200 .cow_metrics = ipv4_cow_metrics,
201 .destroy = ipv4_dst_destroy,
202 .ifdown = ipv4_dst_ifdown,
203 .negative_advice = ipv4_negative_advice,
204 .link_failure = ipv4_link_failure,
205 .update_pmtu = ip_rt_update_pmtu,
206 .local_out = __ip_local_out,
207 .neigh_lookup = ipv4_neigh_lookup,
210 #define ECN_OR_COST(class) TC_PRIO_##class
212 const __u8 ip_tos2prio[16] = {
214 ECN_OR_COST(BESTEFFORT),
216 ECN_OR_COST(BESTEFFORT),
222 ECN_OR_COST(INTERACTIVE),
224 ECN_OR_COST(INTERACTIVE),
225 TC_PRIO_INTERACTIVE_BULK,
226 ECN_OR_COST(INTERACTIVE_BULK),
227 TC_PRIO_INTERACTIVE_BULK,
228 ECN_OR_COST(INTERACTIVE_BULK)
230 EXPORT_SYMBOL(ip_tos2prio);
236 /* The locking scheme is rather straight forward:
238 * 1) Read-Copy Update protects the buckets of the central route hash.
239 * 2) Only writers remove entries, and they hold the lock
240 * as they look at rtable reference counts.
241 * 3) Only readers acquire references to rtable entries,
242 * they do so with atomic increments and with the
246 struct rt_hash_bucket {
247 struct rtable __rcu *chain;
250 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
251 defined(CONFIG_PROVE_LOCKING)
253 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
254 * The size of this table is a power of two and depends on the number of CPUS.
255 * (on lockdep we have a quite big spinlock_t, so keep the size down there)
257 #ifdef CONFIG_LOCKDEP
258 # define RT_HASH_LOCK_SZ 256
261 # define RT_HASH_LOCK_SZ 4096
263 # define RT_HASH_LOCK_SZ 2048
265 # define RT_HASH_LOCK_SZ 1024
267 # define RT_HASH_LOCK_SZ 512
269 # define RT_HASH_LOCK_SZ 256
273 static spinlock_t *rt_hash_locks;
274 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
276 static __init void rt_hash_lock_init(void)
280 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
283 panic("IP: failed to allocate rt_hash_locks\n");
285 for (i = 0; i < RT_HASH_LOCK_SZ; i++)
286 spin_lock_init(&rt_hash_locks[i]);
289 # define rt_hash_lock_addr(slot) NULL
291 static inline void rt_hash_lock_init(void)
296 static struct rt_hash_bucket *rt_hash_table __read_mostly;
297 static unsigned int rt_hash_mask __read_mostly;
298 static unsigned int rt_hash_log __read_mostly;
300 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
301 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
303 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
306 return jhash_3words((__force u32)daddr, (__force u32)saddr,
311 static inline int rt_genid(struct net *net)
313 return atomic_read(&net->ipv4.rt_genid);
316 #ifdef CONFIG_PROC_FS
317 struct rt_cache_iter_state {
318 struct seq_net_private p;
323 static struct rtable *rt_cache_get_first(struct seq_file *seq)
325 struct rt_cache_iter_state *st = seq->private;
326 struct rtable *r = NULL;
328 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
329 if (!rcu_access_pointer(rt_hash_table[st->bucket].chain))
332 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
334 if (dev_net(r->dst.dev) == seq_file_net(seq) &&
335 r->rt_genid == st->genid)
337 r = rcu_dereference_bh(r->dst.rt_next);
339 rcu_read_unlock_bh();
344 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
347 struct rt_cache_iter_state *st = seq->private;
349 r = rcu_dereference_bh(r->dst.rt_next);
351 rcu_read_unlock_bh();
353 if (--st->bucket < 0)
355 } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain));
357 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
362 static struct rtable *rt_cache_get_next(struct seq_file *seq,
365 struct rt_cache_iter_state *st = seq->private;
366 while ((r = __rt_cache_get_next(seq, r)) != NULL) {
367 if (dev_net(r->dst.dev) != seq_file_net(seq))
369 if (r->rt_genid == st->genid)
375 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
377 struct rtable *r = rt_cache_get_first(seq);
380 while (pos && (r = rt_cache_get_next(seq, r)))
382 return pos ? NULL : r;
385 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
387 struct rt_cache_iter_state *st = seq->private;
389 return rt_cache_get_idx(seq, *pos - 1);
390 st->genid = rt_genid(seq_file_net(seq));
391 return SEQ_START_TOKEN;
394 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
398 if (v == SEQ_START_TOKEN)
399 r = rt_cache_get_first(seq);
401 r = rt_cache_get_next(seq, v);
406 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
408 if (v && v != SEQ_START_TOKEN)
409 rcu_read_unlock_bh();
412 static int rt_cache_seq_show(struct seq_file *seq, void *v)
414 if (v == SEQ_START_TOKEN)
415 seq_printf(seq, "%-127s\n",
416 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
417 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
420 struct rtable *r = v;
425 n = dst_get_neighbour_noref(&r->dst);
426 HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0;
429 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
430 "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
431 r->dst.dev ? r->dst.dev->name : "*",
432 (__force u32)r->rt_dst,
433 (__force u32)r->rt_gateway,
434 r->rt_flags, atomic_read(&r->dst.__refcnt),
435 r->dst.__use, 0, (__force u32)r->rt_src,
436 dst_metric_advmss(&r->dst) + 40,
437 dst_metric(&r->dst, RTAX_WINDOW),
438 (int)((dst_metric(&r->dst, RTAX_RTT) >> 3) +
439 dst_metric(&r->dst, RTAX_RTTVAR)),
443 r->rt_spec_dst, &len);
445 seq_printf(seq, "%*s\n", 127 - len, "");
450 static const struct seq_operations rt_cache_seq_ops = {
451 .start = rt_cache_seq_start,
452 .next = rt_cache_seq_next,
453 .stop = rt_cache_seq_stop,
454 .show = rt_cache_seq_show,
457 static int rt_cache_seq_open(struct inode *inode, struct file *file)
459 return seq_open_net(inode, file, &rt_cache_seq_ops,
460 sizeof(struct rt_cache_iter_state));
463 static const struct file_operations rt_cache_seq_fops = {
464 .owner = THIS_MODULE,
465 .open = rt_cache_seq_open,
468 .release = seq_release_net,
472 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
477 return SEQ_START_TOKEN;
479 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
480 if (!cpu_possible(cpu))
483 return &per_cpu(rt_cache_stat, cpu);
488 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
492 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
493 if (!cpu_possible(cpu))
496 return &per_cpu(rt_cache_stat, cpu);
502 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
507 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
509 struct rt_cache_stat *st = v;
511 if (v == SEQ_START_TOKEN) {
512 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");
516 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
517 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
518 dst_entries_get_slow(&ipv4_dst_ops),
541 static const struct seq_operations rt_cpu_seq_ops = {
542 .start = rt_cpu_seq_start,
543 .next = rt_cpu_seq_next,
544 .stop = rt_cpu_seq_stop,
545 .show = rt_cpu_seq_show,
549 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
551 return seq_open(file, &rt_cpu_seq_ops);
554 static const struct file_operations rt_cpu_seq_fops = {
555 .owner = THIS_MODULE,
556 .open = rt_cpu_seq_open,
559 .release = seq_release,
562 #ifdef CONFIG_IP_ROUTE_CLASSID
563 static int rt_acct_proc_show(struct seq_file *m, void *v)
565 struct ip_rt_acct *dst, *src;
568 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
572 for_each_possible_cpu(i) {
573 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
574 for (j = 0; j < 256; j++) {
575 dst[j].o_bytes += src[j].o_bytes;
576 dst[j].o_packets += src[j].o_packets;
577 dst[j].i_bytes += src[j].i_bytes;
578 dst[j].i_packets += src[j].i_packets;
582 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
587 static int rt_acct_proc_open(struct inode *inode, struct file *file)
589 return single_open(file, rt_acct_proc_show, NULL);
592 static const struct file_operations rt_acct_proc_fops = {
593 .owner = THIS_MODULE,
594 .open = rt_acct_proc_open,
597 .release = single_release,
601 static int __net_init ip_rt_do_proc_init(struct net *net)
603 struct proc_dir_entry *pde;
605 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
610 pde = proc_create("rt_cache", S_IRUGO,
611 net->proc_net_stat, &rt_cpu_seq_fops);
615 #ifdef CONFIG_IP_ROUTE_CLASSID
616 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
622 #ifdef CONFIG_IP_ROUTE_CLASSID
624 remove_proc_entry("rt_cache", net->proc_net_stat);
627 remove_proc_entry("rt_cache", net->proc_net);
632 static void __net_exit ip_rt_do_proc_exit(struct net *net)
634 remove_proc_entry("rt_cache", net->proc_net_stat);
635 remove_proc_entry("rt_cache", net->proc_net);
636 #ifdef CONFIG_IP_ROUTE_CLASSID
637 remove_proc_entry("rt_acct", net->proc_net);
641 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
642 .init = ip_rt_do_proc_init,
643 .exit = ip_rt_do_proc_exit,
646 static int __init ip_rt_proc_init(void)
648 return register_pernet_subsys(&ip_rt_proc_ops);
652 static inline int ip_rt_proc_init(void)
656 #endif /* CONFIG_PROC_FS */
658 static inline void rt_free(struct rtable *rt)
660 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
663 static inline void rt_drop(struct rtable *rt)
666 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
669 static inline int rt_fast_clean(struct rtable *rth)
671 /* Kill broadcast/multicast entries very aggresively, if they
672 collide in hash table with more useful entries */
673 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
674 rt_is_input_route(rth) && rth->dst.rt_next;
677 static inline int rt_valuable(struct rtable *rth)
679 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
680 (rt_has_peer(rth) && rt_peer_ptr(rth)->pmtu_expires);
683 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
688 if (atomic_read(&rth->dst.__refcnt))
691 age = jiffies - rth->dst.lastuse;
692 if ((age <= tmo1 && !rt_fast_clean(rth)) ||
693 (age <= tmo2 && rt_valuable(rth)))
699 /* Bits of score are:
701 * 30: not quite useless
702 * 29..0: usage counter
704 static inline u32 rt_score(struct rtable *rt)
706 u32 score = jiffies - rt->dst.lastuse;
708 score = ~score & ~(3<<30);
713 if (rt_is_output_route(rt) ||
714 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
720 static inline bool rt_caching(const struct net *net)
722 return net->ipv4.current_rt_cache_rebuild_count <=
723 net->ipv4.sysctl_rt_cache_rebuild_count;
726 static inline bool compare_hash_inputs(const struct rtable *rt1,
727 const struct rtable *rt2)
729 return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
730 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
731 (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0);
734 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2)
736 return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
737 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
738 (rt1->rt_mark ^ rt2->rt_mark) |
739 (rt1->rt_key_tos ^ rt2->rt_key_tos) |
740 (rt1->rt_route_iif ^ rt2->rt_route_iif) |
741 (rt1->rt_oif ^ rt2->rt_oif)) == 0;
744 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
746 return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev));
749 static inline int rt_is_expired(struct rtable *rth)
751 return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
755 * Perform a full scan of hash table and free all entries.
756 * Can be called by a softirq or a process.
757 * In the later case, we want to be reschedule if necessary
759 static void rt_do_flush(struct net *net, int process_context)
762 struct rtable *rth, *next;
764 for (i = 0; i <= rt_hash_mask; i++) {
765 struct rtable __rcu **pprev;
768 if (process_context && need_resched())
770 rth = rcu_access_pointer(rt_hash_table[i].chain);
774 spin_lock_bh(rt_hash_lock_addr(i));
777 pprev = &rt_hash_table[i].chain;
778 rth = rcu_dereference_protected(*pprev,
779 lockdep_is_held(rt_hash_lock_addr(i)));
782 next = rcu_dereference_protected(rth->dst.rt_next,
783 lockdep_is_held(rt_hash_lock_addr(i)));
786 net_eq(dev_net(rth->dst.dev), net)) {
787 rcu_assign_pointer(*pprev, next);
788 rcu_assign_pointer(rth->dst.rt_next, list);
791 pprev = &rth->dst.rt_next;
796 spin_unlock_bh(rt_hash_lock_addr(i));
798 for (; list; list = next) {
799 next = rcu_dereference_protected(list->dst.rt_next, 1);
806 * While freeing expired entries, we compute average chain length
807 * and standard deviation, using fixed-point arithmetic.
808 * This to have an estimation of rt_chain_length_max
809 * rt_chain_length_max = max(elasticity, AVG + 4*SD)
810 * We use 3 bits for frational part, and 29 (or 61) for magnitude.
814 #define ONE (1UL << FRACT_BITS)
817 * Given a hash chain and an item in this hash chain,
818 * find if a previous entry has the same hash_inputs
819 * (but differs on tos, mark or oif)
820 * Returns 0 if an alias is found.
821 * Returns ONE if rth has no alias before itself.
823 static int has_noalias(const struct rtable *head, const struct rtable *rth)
825 const struct rtable *aux = head;
828 if (compare_hash_inputs(aux, rth))
830 aux = rcu_dereference_protected(aux->dst.rt_next, 1);
835 static void rt_check_expire(void)
837 static unsigned int rover;
838 unsigned int i = rover, goal;
840 struct rtable __rcu **rthp;
841 unsigned long samples = 0;
842 unsigned long sum = 0, sum2 = 0;
846 delta = jiffies - expires_ljiffies;
847 expires_ljiffies = jiffies;
848 mult = ((u64)delta) << rt_hash_log;
849 if (ip_rt_gc_timeout > 1)
850 do_div(mult, ip_rt_gc_timeout);
851 goal = (unsigned int)mult;
852 if (goal > rt_hash_mask)
853 goal = rt_hash_mask + 1;
854 for (; goal > 0; goal--) {
855 unsigned long tmo = ip_rt_gc_timeout;
856 unsigned long length;
858 i = (i + 1) & rt_hash_mask;
859 rthp = &rt_hash_table[i].chain;
866 if (rcu_dereference_raw(*rthp) == NULL)
869 spin_lock_bh(rt_hash_lock_addr(i));
870 while ((rth = rcu_dereference_protected(*rthp,
871 lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) {
872 prefetch(rth->dst.rt_next);
873 if (rt_is_expired(rth)) {
874 *rthp = rth->dst.rt_next;
878 if (rth->dst.expires) {
879 /* Entry is expired even if it is in use */
880 if (time_before_eq(jiffies, rth->dst.expires)) {
883 rthp = &rth->dst.rt_next;
885 * We only count entries on
886 * a chain with equal hash inputs once
887 * so that entries for different QOS
888 * levels, and other non-hash input
889 * attributes don't unfairly skew
890 * the length computation
892 length += has_noalias(rt_hash_table[i].chain, rth);
895 } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout))
898 /* Cleanup aged off entries. */
899 *rthp = rth->dst.rt_next;
902 spin_unlock_bh(rt_hash_lock_addr(i));
904 sum2 += length*length;
907 unsigned long avg = sum / samples;
908 unsigned long sd = int_sqrt(sum2 / samples - avg*avg);
909 rt_chain_length_max = max_t(unsigned long,
911 (avg + 4*sd) >> FRACT_BITS);
917 * rt_worker_func() is run in process context.
918 * we call rt_check_expire() to scan part of the hash table
920 static void rt_worker_func(struct work_struct *work)
923 schedule_delayed_work(&expires_work, ip_rt_gc_interval);
927 * Perturbation of rt_genid by a small quantity [1..256]
928 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
929 * many times (2^24) without giving recent rt_genid.
930 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
932 static void rt_cache_invalidate(struct net *net)
934 unsigned char shuffle;
936 get_random_bytes(&shuffle, sizeof(shuffle));
937 atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
938 inetpeer_invalidate_family(AF_INET);
942 * delay < 0 : invalidate cache (fast : entries will be deleted later)
943 * delay >= 0 : invalidate & flush cache (can be long)
945 void rt_cache_flush(struct net *net, int delay)
947 rt_cache_invalidate(net);
949 rt_do_flush(net, !in_softirq());
952 /* Flush previous cache invalidated entries from the cache */
953 void rt_cache_flush_batch(struct net *net)
955 rt_do_flush(net, !in_softirq());
958 static void rt_emergency_hash_rebuild(struct net *net)
960 net_warn_ratelimited("Route hash chain too long!\n");
961 rt_cache_invalidate(net);
965 Short description of GC goals.
967 We want to build algorithm, which will keep routing cache
968 at some equilibrium point, when number of aged off entries
969 is kept approximately equal to newly generated ones.
971 Current expiration strength is variable "expire".
972 We try to adjust it dynamically, so that if networking
973 is idle expires is large enough to keep enough of warm entries,
974 and when load increases it reduces to limit cache size.
977 static int rt_garbage_collect(struct dst_ops *ops)
979 static unsigned long expire = RT_GC_TIMEOUT;
980 static unsigned long last_gc;
982 static int equilibrium;
984 struct rtable __rcu **rthp;
985 unsigned long now = jiffies;
987 int entries = dst_entries_get_fast(&ipv4_dst_ops);
990 * Garbage collection is pretty expensive,
991 * do not make it too frequently.
994 RT_CACHE_STAT_INC(gc_total);
996 if (now - last_gc < ip_rt_gc_min_interval &&
997 entries < ip_rt_max_size) {
998 RT_CACHE_STAT_INC(gc_ignored);
1002 entries = dst_entries_get_slow(&ipv4_dst_ops);
1003 /* Calculate number of entries, which we want to expire now. */
1004 goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
1006 if (equilibrium < ipv4_dst_ops.gc_thresh)
1007 equilibrium = ipv4_dst_ops.gc_thresh;
1008 goal = entries - equilibrium;
1010 equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
1011 goal = entries - equilibrium;
1014 /* We are in dangerous area. Try to reduce cache really
1017 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
1018 equilibrium = entries - goal;
1021 if (now - last_gc >= ip_rt_gc_min_interval)
1025 equilibrium += goal;
1032 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
1033 unsigned long tmo = expire;
1035 k = (k + 1) & rt_hash_mask;
1036 rthp = &rt_hash_table[k].chain;
1037 spin_lock_bh(rt_hash_lock_addr(k));
1038 while ((rth = rcu_dereference_protected(*rthp,
1039 lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
1040 if (!rt_is_expired(rth) &&
1041 !rt_may_expire(rth, tmo, expire)) {
1043 rthp = &rth->dst.rt_next;
1046 *rthp = rth->dst.rt_next;
1050 spin_unlock_bh(rt_hash_lock_addr(k));
1059 /* Goal is not achieved. We stop process if:
1061 - if expire reduced to zero. Otherwise, expire is halfed.
1062 - if table is not full.
1063 - if we are called from interrupt.
1064 - jiffies check is just fallback/debug loop breaker.
1065 We will not spin here for long time in any case.
1068 RT_CACHE_STAT_INC(gc_goal_miss);
1075 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1077 } while (!in_softirq() && time_before_eq(jiffies, now));
1079 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1081 if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
1083 net_warn_ratelimited("dst cache overflow\n");
1084 RT_CACHE_STAT_INC(gc_dst_overflow);
1088 expire += ip_rt_gc_min_interval;
1089 if (expire > ip_rt_gc_timeout ||
1090 dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
1091 dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
1092 expire = ip_rt_gc_timeout;
1097 * Returns number of entries in a hash chain that have different hash_inputs
1099 static int slow_chain_length(const struct rtable *head)
1102 const struct rtable *rth = head;
1105 length += has_noalias(head, rth);
1106 rth = rcu_dereference_protected(rth->dst.rt_next, 1);
1108 return length >> FRACT_BITS;
1111 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr)
1113 static const __be32 inaddr_any = 0;
1114 struct net_device *dev = dst->dev;
1115 const __be32 *pkey = daddr;
1116 const struct rtable *rt;
1117 struct neighbour *n;
1119 rt = (const struct rtable *) dst;
1121 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
1123 else if (rt->rt_gateway)
1124 pkey = (const __be32 *) &rt->rt_gateway;
1126 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
1129 return neigh_create(&arp_tbl, pkey, dev);
1132 static int rt_bind_neighbour(struct rtable *rt)
1134 struct neighbour *n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1137 dst_set_neighbour(&rt->dst, n);
1142 static struct rtable *rt_intern_hash(unsigned int hash, struct rtable *rt,
1143 struct sk_buff *skb, int ifindex)
1145 struct rtable *rth, *cand;
1146 struct rtable __rcu **rthp, **candp;
1150 int attempts = !in_softirq();
1154 min_score = ~(u32)0;
1159 if (!rt_caching(dev_net(rt->dst.dev))) {
1161 * If we're not caching, just tell the caller we
1162 * were successful and don't touch the route. The
1163 * caller hold the sole reference to the cache entry, and
1164 * it will be released when the caller is done with it.
1165 * If we drop it here, the callers have no way to resolve routes
1166 * when we're not caching. Instead, just point *rp at rt, so
1167 * the caller gets a single use out of the route
1168 * Note that we do rt_free on this new route entry, so that
1169 * once its refcount hits zero, we are still able to reap it
1171 * Note: To avoid expensive rcu stuff for this uncached dst,
1172 * we set DST_NOCACHE so that dst_release() can free dst without
1173 * waiting a grace period.
1176 rt->dst.flags |= DST_NOCACHE;
1177 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1178 int err = rt_bind_neighbour(rt);
1180 net_warn_ratelimited("Neighbour table failure & not caching routes\n");
1182 return ERR_PTR(err);
1189 rthp = &rt_hash_table[hash].chain;
1191 spin_lock_bh(rt_hash_lock_addr(hash));
1192 while ((rth = rcu_dereference_protected(*rthp,
1193 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1194 if (rt_is_expired(rth)) {
1195 *rthp = rth->dst.rt_next;
1199 if (compare_keys(rth, rt) && compare_netns(rth, rt)) {
1201 *rthp = rth->dst.rt_next;
1203 * Since lookup is lockfree, the deletion
1204 * must be visible to another weakly ordered CPU before
1205 * the insertion at the start of the hash chain.
1207 rcu_assign_pointer(rth->dst.rt_next,
1208 rt_hash_table[hash].chain);
1210 * Since lookup is lockfree, the update writes
1211 * must be ordered for consistency on SMP.
1213 rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1215 dst_use(&rth->dst, now);
1216 spin_unlock_bh(rt_hash_lock_addr(hash));
1220 skb_dst_set(skb, &rth->dst);
1224 if (!atomic_read(&rth->dst.__refcnt)) {
1225 u32 score = rt_score(rth);
1227 if (score <= min_score) {
1236 rthp = &rth->dst.rt_next;
1240 /* ip_rt_gc_elasticity used to be average length of chain
1241 * length, when exceeded gc becomes really aggressive.
1243 * The second limit is less certain. At the moment it allows
1244 * only 2 entries per bucket. We will see.
1246 if (chain_length > ip_rt_gc_elasticity) {
1247 *candp = cand->dst.rt_next;
1251 if (chain_length > rt_chain_length_max &&
1252 slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
1253 struct net *net = dev_net(rt->dst.dev);
1254 int num = ++net->ipv4.current_rt_cache_rebuild_count;
1255 if (!rt_caching(net)) {
1256 pr_warn("%s: %d rebuilds is over limit, route caching disabled\n",
1257 rt->dst.dev->name, num);
1259 rt_emergency_hash_rebuild(net);
1260 spin_unlock_bh(rt_hash_lock_addr(hash));
1262 hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1263 ifindex, rt_genid(net));
1268 /* Try to bind route to arp only if it is output
1269 route or unicast forwarding path.
1271 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1272 int err = rt_bind_neighbour(rt);
1274 spin_unlock_bh(rt_hash_lock_addr(hash));
1276 if (err != -ENOBUFS) {
1278 return ERR_PTR(err);
1281 /* Neighbour tables are full and nothing
1282 can be released. Try to shrink route cache,
1283 it is most likely it holds some neighbour records.
1285 if (attempts-- > 0) {
1286 int saved_elasticity = ip_rt_gc_elasticity;
1287 int saved_int = ip_rt_gc_min_interval;
1288 ip_rt_gc_elasticity = 1;
1289 ip_rt_gc_min_interval = 0;
1290 rt_garbage_collect(&ipv4_dst_ops);
1291 ip_rt_gc_min_interval = saved_int;
1292 ip_rt_gc_elasticity = saved_elasticity;
1296 net_warn_ratelimited("Neighbour table overflow\n");
1298 return ERR_PTR(-ENOBUFS);
1302 rt->dst.rt_next = rt_hash_table[hash].chain;
1305 * Since lookup is lockfree, we must make sure
1306 * previous writes to rt are committed to memory
1307 * before making rt visible to other CPUS.
1309 rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1311 spin_unlock_bh(rt_hash_lock_addr(hash));
1315 skb_dst_set(skb, &rt->dst);
1319 static atomic_t __rt_peer_genid = ATOMIC_INIT(0);
1321 static u32 rt_peer_genid(void)
1323 return atomic_read(&__rt_peer_genid);
1326 void rt_bind_peer(struct rtable *rt, __be32 daddr, int create)
1328 struct inet_peer_base *base;
1329 struct inet_peer *peer;
1331 base = inetpeer_base_ptr(rt->_peer);
1335 peer = inet_getpeer_v4(base, daddr, create);
1337 if (!rt_set_peer(rt, peer))
1340 rt->rt_peer_genid = rt_peer_genid();
1345 * Peer allocation may fail only in serious out-of-memory conditions. However
1346 * we still can generate some output.
1347 * Random ID selection looks a bit dangerous because we have no chances to
1348 * select ID being unique in a reasonable period of time.
1349 * But broken packet identifier may be better than no packet at all.
1351 static void ip_select_fb_ident(struct iphdr *iph)
1353 static DEFINE_SPINLOCK(ip_fb_id_lock);
1354 static u32 ip_fallback_id;
1357 spin_lock_bh(&ip_fb_id_lock);
1358 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1359 iph->id = htons(salt & 0xFFFF);
1360 ip_fallback_id = salt;
1361 spin_unlock_bh(&ip_fb_id_lock);
1364 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1366 struct rtable *rt = (struct rtable *) dst;
1368 if (rt && !(rt->dst.flags & DST_NOPEER)) {
1369 struct inet_peer *peer = rt_get_peer_create(rt, rt->rt_dst);
1371 /* If peer is attached to destination, it is never detached,
1372 so that we need not to grab a lock to dereference it.
1375 iph->id = htons(inet_getid(peer, more));
1379 pr_debug("rt_bind_peer(0) @%p\n", __builtin_return_address(0));
1381 ip_select_fb_ident(iph);
1383 EXPORT_SYMBOL(__ip_select_ident);
1385 static void rt_del(unsigned int hash, struct rtable *rt)
1387 struct rtable __rcu **rthp;
1390 rthp = &rt_hash_table[hash].chain;
1391 spin_lock_bh(rt_hash_lock_addr(hash));
1393 while ((aux = rcu_dereference_protected(*rthp,
1394 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1395 if (aux == rt || rt_is_expired(aux)) {
1396 *rthp = aux->dst.rt_next;
1400 rthp = &aux->dst.rt_next;
1402 spin_unlock_bh(rt_hash_lock_addr(hash));
1405 static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
1407 struct rtable *rt = (struct rtable *) dst;
1408 __be32 orig_gw = rt->rt_gateway;
1409 struct neighbour *n, *old_n;
1411 dst_confirm(&rt->dst);
1413 rt->rt_gateway = peer->redirect_learned.a4;
1415 n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1417 rt->rt_gateway = orig_gw;
1420 old_n = xchg(&rt->dst._neighbour, n);
1422 neigh_release(old_n);
1423 if (!(n->nud_state & NUD_VALID)) {
1424 neigh_event_send(n, NULL);
1426 rt->rt_flags |= RTCF_REDIRECTED;
1427 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
1431 /* called in rcu_read_lock() section */
1432 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1433 __be32 saddr, struct net_device *dev)
1436 struct in_device *in_dev = __in_dev_get_rcu(dev);
1437 __be32 skeys[2] = { saddr, 0 };
1438 int ikeys[2] = { dev->ifindex, 0 };
1439 struct inet_peer *peer;
1446 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1447 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1448 ipv4_is_zeronet(new_gw))
1449 goto reject_redirect;
1451 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1452 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1453 goto reject_redirect;
1454 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1455 goto reject_redirect;
1457 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1458 goto reject_redirect;
1461 for (s = 0; s < 2; s++) {
1462 for (i = 0; i < 2; i++) {
1464 struct rtable __rcu **rthp;
1467 hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net));
1469 rthp = &rt_hash_table[hash].chain;
1471 while ((rt = rcu_dereference(*rthp)) != NULL) {
1472 rthp = &rt->dst.rt_next;
1474 if (rt->rt_key_dst != daddr ||
1475 rt->rt_key_src != skeys[s] ||
1476 rt->rt_oif != ikeys[i] ||
1477 rt_is_input_route(rt) ||
1478 rt_is_expired(rt) ||
1479 !net_eq(dev_net(rt->dst.dev), net) ||
1481 rt->dst.dev != dev ||
1482 rt->rt_gateway != old_gw)
1485 peer = rt_get_peer_create(rt, rt->rt_dst);
1487 if (peer->redirect_learned.a4 != new_gw) {
1488 peer->redirect_learned.a4 = new_gw;
1489 atomic_inc(&__rt_peer_genid);
1491 check_peer_redir(&rt->dst, peer);
1499 #ifdef CONFIG_IP_ROUTE_VERBOSE
1500 if (IN_DEV_LOG_MARTIANS(in_dev))
1501 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
1502 " Advised path = %pI4 -> %pI4\n",
1503 &old_gw, dev->name, &new_gw,
1509 static bool peer_pmtu_expired(struct inet_peer *peer)
1511 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1514 time_after_eq(jiffies, orig) &&
1515 cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1518 static bool peer_pmtu_cleaned(struct inet_peer *peer)
1520 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1523 cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1526 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1528 struct rtable *rt = (struct rtable *)dst;
1529 struct dst_entry *ret = dst;
1532 if (dst->obsolete > 0) {
1535 } else if (rt->rt_flags & RTCF_REDIRECTED) {
1536 unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1538 rt_genid(dev_net(dst->dev)));
1541 } else if (rt_has_peer(rt)) {
1542 struct inet_peer *peer = rt_peer_ptr(rt);
1543 if (peer_pmtu_expired(peer))
1544 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1552 * 1. The first ip_rt_redirect_number redirects are sent
1553 * with exponential backoff, then we stop sending them at all,
1554 * assuming that the host ignores our redirects.
1555 * 2. If we did not see packets requiring redirects
1556 * during ip_rt_redirect_silence, we assume that the host
1557 * forgot redirected route and start to send redirects again.
1559 * This algorithm is much cheaper and more intelligent than dumb load limiting
1562 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1563 * and "frag. need" (breaks PMTU discovery) in icmp.c.
1566 void ip_rt_send_redirect(struct sk_buff *skb)
1568 struct rtable *rt = skb_rtable(skb);
1569 struct in_device *in_dev;
1570 struct inet_peer *peer;
1574 in_dev = __in_dev_get_rcu(rt->dst.dev);
1575 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1579 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1582 peer = rt_get_peer_create(rt, rt->rt_dst);
1584 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1588 /* No redirected packets during ip_rt_redirect_silence;
1589 * reset the algorithm.
1591 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1592 peer->rate_tokens = 0;
1594 /* Too many ignored redirects; do not send anything
1595 * set dst.rate_last to the last seen redirected packet.
1597 if (peer->rate_tokens >= ip_rt_redirect_number) {
1598 peer->rate_last = jiffies;
1602 /* Check for load limit; set rate_last to the latest sent
1605 if (peer->rate_tokens == 0 ||
1608 (ip_rt_redirect_load << peer->rate_tokens)))) {
1609 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1610 peer->rate_last = jiffies;
1611 ++peer->rate_tokens;
1612 #ifdef CONFIG_IP_ROUTE_VERBOSE
1614 peer->rate_tokens == ip_rt_redirect_number)
1615 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
1616 &ip_hdr(skb)->saddr, rt->rt_iif,
1617 &rt->rt_dst, &rt->rt_gateway);
1622 static int ip_error(struct sk_buff *skb)
1624 struct rtable *rt = skb_rtable(skb);
1625 struct inet_peer *peer;
1630 switch (rt->dst.error) {
1635 code = ICMP_HOST_UNREACH;
1638 code = ICMP_NET_UNREACH;
1639 IP_INC_STATS_BH(dev_net(rt->dst.dev),
1640 IPSTATS_MIB_INNOROUTES);
1643 code = ICMP_PKT_FILTERED;
1647 peer = rt_get_peer_create(rt, rt->rt_dst);
1652 peer->rate_tokens += now - peer->rate_last;
1653 if (peer->rate_tokens > ip_rt_error_burst)
1654 peer->rate_tokens = ip_rt_error_burst;
1655 peer->rate_last = now;
1656 if (peer->rate_tokens >= ip_rt_error_cost)
1657 peer->rate_tokens -= ip_rt_error_cost;
1662 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1664 out: kfree_skb(skb);
1668 static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
1670 unsigned long expires = ACCESS_ONCE(peer->pmtu_expires);
1674 if (time_before(jiffies, expires)) {
1675 u32 orig_dst_mtu = dst_mtu(dst);
1676 if (peer->pmtu_learned < orig_dst_mtu) {
1677 if (!peer->pmtu_orig)
1678 peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU);
1679 dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned);
1681 } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires)
1682 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1685 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1687 struct rtable *rt = (struct rtable *) dst;
1688 struct inet_peer *peer;
1692 peer = rt_get_peer_create(rt, rt->rt_dst);
1694 unsigned long pmtu_expires = ACCESS_ONCE(peer->pmtu_expires);
1696 if (mtu < ip_rt_min_pmtu)
1697 mtu = ip_rt_min_pmtu;
1698 if (!pmtu_expires || mtu < peer->pmtu_learned) {
1700 pmtu_expires = jiffies + ip_rt_mtu_expires;
1704 peer->pmtu_learned = mtu;
1705 peer->pmtu_expires = pmtu_expires;
1707 atomic_inc(&__rt_peer_genid);
1708 rt->rt_peer_genid = rt_peer_genid();
1710 check_peer_pmtu(dst, peer);
1714 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1715 int oif, u32 mark, u8 protocol, int flow_flags)
1717 const struct iphdr *iph = (const struct iphdr *)skb->data;
1721 flowi4_init_output(&fl4, oif, mark, RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
1722 protocol, flow_flags | FLOWI_FLAG_PRECOW_METRICS,
1723 iph->daddr, iph->saddr, 0, 0);
1724 rt = __ip_route_output_key(net, &fl4);
1726 ip_rt_update_pmtu(&rt->dst, mtu);
1730 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1732 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1734 const struct inet_sock *inet = inet_sk(sk);
1736 return ipv4_update_pmtu(skb, sock_net(sk), mtu,
1737 sk->sk_bound_dev_if, sk->sk_mark,
1738 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
1739 inet_sk_flowi_flags(sk));
1741 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1743 static void ipv4_validate_peer(struct rtable *rt)
1745 if (rt->rt_peer_genid != rt_peer_genid()) {
1746 struct inet_peer *peer = rt_get_peer(rt, rt->rt_dst);
1749 check_peer_pmtu(&rt->dst, peer);
1751 if (peer->redirect_learned.a4 &&
1752 peer->redirect_learned.a4 != rt->rt_gateway)
1753 check_peer_redir(&rt->dst, peer);
1756 rt->rt_peer_genid = rt_peer_genid();
1760 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1762 struct rtable *rt = (struct rtable *) dst;
1764 if (rt_is_expired(rt))
1766 ipv4_validate_peer(rt);
1770 static void ipv4_dst_destroy(struct dst_entry *dst)
1772 struct rtable *rt = (struct rtable *) dst;
1775 fib_info_put(rt->fi);
1778 if (rt_has_peer(rt)) {
1779 struct inet_peer *peer = rt_peer_ptr(rt);
1785 static void ipv4_link_failure(struct sk_buff *skb)
1789 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1791 rt = skb_rtable(skb);
1792 if (rt && rt_has_peer(rt)) {
1793 struct inet_peer *peer = rt_peer_ptr(rt);
1794 if (peer_pmtu_cleaned(peer))
1795 dst_metric_set(&rt->dst, RTAX_MTU, peer->pmtu_orig);
1799 static int ip_rt_bug(struct sk_buff *skb)
1801 pr_debug("%s: %pI4 -> %pI4, %s\n",
1802 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1803 skb->dev ? skb->dev->name : "?");
1810 We do not cache source address of outgoing interface,
1811 because it is used only by IP RR, TS and SRR options,
1812 so that it out of fast path.
1814 BTW remember: "addr" is allowed to be not aligned
1818 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1822 if (rt_is_output_route(rt))
1823 src = ip_hdr(skb)->saddr;
1825 struct fib_result res;
1831 memset(&fl4, 0, sizeof(fl4));
1832 fl4.daddr = iph->daddr;
1833 fl4.saddr = iph->saddr;
1834 fl4.flowi4_tos = RT_TOS(iph->tos);
1835 fl4.flowi4_oif = rt->dst.dev->ifindex;
1836 fl4.flowi4_iif = skb->dev->ifindex;
1837 fl4.flowi4_mark = skb->mark;
1840 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1841 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1843 src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1847 memcpy(addr, &src, 4);
1850 #ifdef CONFIG_IP_ROUTE_CLASSID
1851 static void set_class_tag(struct rtable *rt, u32 tag)
1853 if (!(rt->dst.tclassid & 0xFFFF))
1854 rt->dst.tclassid |= tag & 0xFFFF;
1855 if (!(rt->dst.tclassid & 0xFFFF0000))
1856 rt->dst.tclassid |= tag & 0xFFFF0000;
1860 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1862 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1865 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1867 if (advmss > 65535 - 40)
1868 advmss = 65535 - 40;
1873 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1875 const struct rtable *rt = (const struct rtable *) dst;
1876 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1878 if (mtu && rt_is_output_route(rt))
1881 mtu = dst->dev->mtu;
1883 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1885 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1889 if (mtu > IP_MAX_MTU)
1895 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1896 struct fib_info *fi)
1898 struct inet_peer_base *base;
1899 struct inet_peer *peer;
1902 /* If a peer entry exists for this destination, we must hook
1903 * it up in order to get at cached metrics.
1905 if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
1908 base = inetpeer_base_ptr(rt->_peer);
1911 peer = inet_getpeer_v4(base, rt->rt_dst, create);
1913 __rt_set_peer(rt, peer);
1914 rt->rt_peer_genid = rt_peer_genid();
1915 if (inet_metrics_new(peer))
1916 memcpy(peer->metrics, fi->fib_metrics,
1917 sizeof(u32) * RTAX_MAX);
1918 dst_init_metrics(&rt->dst, peer->metrics, false);
1920 check_peer_pmtu(&rt->dst, peer);
1922 if (peer->redirect_learned.a4 &&
1923 peer->redirect_learned.a4 != rt->rt_gateway) {
1924 rt->rt_gateway = peer->redirect_learned.a4;
1925 rt->rt_flags |= RTCF_REDIRECTED;
1928 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1930 atomic_inc(&fi->fib_clntref);
1932 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1936 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1937 const struct fib_result *res,
1938 struct fib_info *fi, u16 type, u32 itag)
1940 struct dst_entry *dst = &rt->dst;
1943 if (FIB_RES_GW(*res) &&
1944 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1945 rt->rt_gateway = FIB_RES_GW(*res);
1946 rt_init_metrics(rt, fl4, fi);
1947 #ifdef CONFIG_IP_ROUTE_CLASSID
1948 dst->tclassid = FIB_RES_NH(*res).nh_tclassid;
1952 if (dst_mtu(dst) > IP_MAX_MTU)
1953 dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);
1955 #ifdef CONFIG_IP_ROUTE_CLASSID
1956 #ifdef CONFIG_IP_MULTIPLE_TABLES
1957 set_class_tag(rt, fib_rules_tclass(res));
1959 set_class_tag(rt, itag);
1963 static struct rtable *rt_dst_alloc(struct net_device *dev,
1964 bool nopolicy, bool noxfrm)
1966 return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
1968 (nopolicy ? DST_NOPOLICY : 0) |
1969 (noxfrm ? DST_NOXFRM : 0));
1972 /* called in rcu_read_lock() section */
1973 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1974 u8 tos, struct net_device *dev, int our)
1979 struct in_device *in_dev = __in_dev_get_rcu(dev);
1983 /* Primary sanity checks. */
1988 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1989 skb->protocol != htons(ETH_P_IP))
1992 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1993 if (ipv4_is_loopback(saddr))
1996 if (ipv4_is_zeronet(saddr)) {
1997 if (!ipv4_is_local_multicast(daddr))
1999 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2001 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst,
2006 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
2007 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2011 #ifdef CONFIG_IP_ROUTE_CLASSID
2012 rth->dst.tclassid = itag;
2014 rth->dst.output = ip_rt_bug;
2016 rth->rt_key_dst = daddr;
2017 rth->rt_key_src = saddr;
2018 rth->rt_genid = rt_genid(dev_net(dev));
2019 rth->rt_flags = RTCF_MULTICAST;
2020 rth->rt_type = RTN_MULTICAST;
2021 rth->rt_key_tos = tos;
2022 rth->rt_dst = daddr;
2023 rth->rt_src = saddr;
2024 rth->rt_route_iif = dev->ifindex;
2025 rth->rt_iif = dev->ifindex;
2027 rth->rt_mark = skb->mark;
2028 rth->rt_gateway = daddr;
2029 rth->rt_spec_dst= spec_dst;
2030 rth->rt_peer_genid = 0;
2031 rt_init_peer(rth, dev_net(dev)->ipv4.peers);
2034 rth->dst.input= ip_local_deliver;
2035 rth->rt_flags |= RTCF_LOCAL;
2038 #ifdef CONFIG_IP_MROUTE
2039 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
2040 rth->dst.input = ip_mr_input;
2042 RT_CACHE_STAT_INC(in_slow_mc);
2044 hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
2045 rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
2046 return IS_ERR(rth) ? PTR_ERR(rth) : 0;
2057 static void ip_handle_martian_source(struct net_device *dev,
2058 struct in_device *in_dev,
2059 struct sk_buff *skb,
2063 RT_CACHE_STAT_INC(in_martian_src);
2064 #ifdef CONFIG_IP_ROUTE_VERBOSE
2065 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
2067 * RFC1812 recommendation, if source is martian,
2068 * the only hint is MAC header.
2070 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
2071 &daddr, &saddr, dev->name);
2072 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
2073 print_hex_dump(KERN_WARNING, "ll header: ",
2074 DUMP_PREFIX_OFFSET, 16, 1,
2075 skb_mac_header(skb),
2076 dev->hard_header_len, true);
2082 /* called in rcu_read_lock() section */
2083 static int __mkroute_input(struct sk_buff *skb,
2084 const struct fib_result *res,
2085 struct in_device *in_dev,
2086 __be32 daddr, __be32 saddr, u32 tos,
2087 struct rtable **result)
2091 struct in_device *out_dev;
2092 unsigned int flags = 0;
2096 /* get a working reference to the output device */
2097 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
2098 if (out_dev == NULL) {
2099 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
2104 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
2105 in_dev->dev, &spec_dst, &itag);
2107 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
2114 flags |= RTCF_DIRECTSRC;
2116 if (out_dev == in_dev && err &&
2117 (IN_DEV_SHARED_MEDIA(out_dev) ||
2118 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
2119 flags |= RTCF_DOREDIRECT;
2121 if (skb->protocol != htons(ETH_P_IP)) {
2122 /* Not IP (i.e. ARP). Do not create route, if it is
2123 * invalid for proxy arp. DNAT routes are always valid.
2125 * Proxy arp feature have been extended to allow, ARP
2126 * replies back to the same interface, to support
2127 * Private VLAN switch technologies. See arp.c.
2129 if (out_dev == in_dev &&
2130 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2136 rth = rt_dst_alloc(out_dev->dev,
2137 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2138 IN_DEV_CONF_GET(out_dev, NOXFRM));
2144 rth->rt_key_dst = daddr;
2145 rth->rt_key_src = saddr;
2146 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
2147 rth->rt_flags = flags;
2148 rth->rt_type = res->type;
2149 rth->rt_key_tos = tos;
2150 rth->rt_dst = daddr;
2151 rth->rt_src = saddr;
2152 rth->rt_route_iif = in_dev->dev->ifindex;
2153 rth->rt_iif = in_dev->dev->ifindex;
2155 rth->rt_mark = skb->mark;
2156 rth->rt_gateway = daddr;
2157 rth->rt_spec_dst= spec_dst;
2158 rth->rt_peer_genid = 0;
2159 rt_init_peer(rth, &res->table->tb_peers);
2162 rth->dst.input = ip_forward;
2163 rth->dst.output = ip_output;
2165 rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
2173 static int ip_mkroute_input(struct sk_buff *skb,
2174 struct fib_result *res,
2175 const struct flowi4 *fl4,
2176 struct in_device *in_dev,
2177 __be32 daddr, __be32 saddr, u32 tos)
2179 struct rtable *rth = NULL;
2183 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2184 if (res->fi && res->fi->fib_nhs > 1)
2185 fib_select_multipath(res);
2188 /* create a routing cache entry */
2189 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
2193 /* put it into the cache */
2194 hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
2195 rt_genid(dev_net(rth->dst.dev)));
2196 rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
2198 return PTR_ERR(rth);
2203 * NOTE. We drop all the packets that has local source
2204 * addresses, because every properly looped back packet
2205 * must have correct destination already attached by output routine.
2207 * Such approach solves two big problems:
2208 * 1. Not simplex devices are handled properly.
2209 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2210 * called with rcu_read_lock()
2213 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2214 u8 tos, struct net_device *dev)
2216 struct fib_result res;
2217 struct in_device *in_dev = __in_dev_get_rcu(dev);
2219 unsigned int flags = 0;
2225 struct net *net = dev_net(dev);
2227 /* IP on this device is disabled. */
2232 /* Check for the most weird martians, which can be not detected
2236 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2237 goto martian_source;
2239 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2242 /* Accept zero addresses only to limited broadcast;
2243 * I even do not know to fix it or not. Waiting for complains :-)
2245 if (ipv4_is_zeronet(saddr))
2246 goto martian_source;
2248 if (ipv4_is_zeronet(daddr))
2249 goto martian_destination;
2251 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
2252 if (ipv4_is_loopback(daddr))
2253 goto martian_destination;
2255 if (ipv4_is_loopback(saddr))
2256 goto martian_source;
2260 * Now we are ready to route packet.
2263 fl4.flowi4_iif = dev->ifindex;
2264 fl4.flowi4_mark = skb->mark;
2265 fl4.flowi4_tos = tos;
2266 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2269 err = fib_lookup(net, &fl4, &res);
2271 if (!IN_DEV_FORWARD(in_dev))
2276 RT_CACHE_STAT_INC(in_slow_tot);
2278 if (res.type == RTN_BROADCAST)
2281 if (res.type == RTN_LOCAL) {
2282 err = fib_validate_source(skb, saddr, daddr, tos,
2283 net->loopback_dev->ifindex,
2284 dev, &spec_dst, &itag);
2286 goto martian_source_keep_err;
2288 flags |= RTCF_DIRECTSRC;
2293 if (!IN_DEV_FORWARD(in_dev))
2295 if (res.type != RTN_UNICAST)
2296 goto martian_destination;
2298 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2302 if (skb->protocol != htons(ETH_P_IP))
2305 if (ipv4_is_zeronet(saddr))
2306 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2308 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst,
2311 goto martian_source_keep_err;
2313 flags |= RTCF_DIRECTSRC;
2315 flags |= RTCF_BROADCAST;
2316 res.type = RTN_BROADCAST;
2317 RT_CACHE_STAT_INC(in_brd);
2320 rth = rt_dst_alloc(net->loopback_dev,
2321 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2325 rth->dst.input= ip_local_deliver;
2326 rth->dst.output= ip_rt_bug;
2327 #ifdef CONFIG_IP_ROUTE_CLASSID
2328 rth->dst.tclassid = itag;
2331 rth->rt_key_dst = daddr;
2332 rth->rt_key_src = saddr;
2333 rth->rt_genid = rt_genid(net);
2334 rth->rt_flags = flags|RTCF_LOCAL;
2335 rth->rt_type = res.type;
2336 rth->rt_key_tos = tos;
2337 rth->rt_dst = daddr;
2338 rth->rt_src = saddr;
2339 #ifdef CONFIG_IP_ROUTE_CLASSID
2340 rth->dst.tclassid = itag;
2342 rth->rt_route_iif = dev->ifindex;
2343 rth->rt_iif = dev->ifindex;
2345 rth->rt_mark = skb->mark;
2346 rth->rt_gateway = daddr;
2347 rth->rt_spec_dst= spec_dst;
2348 rth->rt_peer_genid = 0;
2349 rt_init_peer(rth, net->ipv4.peers);
2351 if (res.type == RTN_UNREACHABLE) {
2352 rth->dst.input= ip_error;
2353 rth->dst.error= -err;
2354 rth->rt_flags &= ~RTCF_LOCAL;
2356 hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2357 rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2364 RT_CACHE_STAT_INC(in_no_route);
2365 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2366 res.type = RTN_UNREACHABLE;
2372 * Do not cache martian addresses: they should be logged (RFC1812)
2374 martian_destination:
2375 RT_CACHE_STAT_INC(in_martian_dst);
2376 #ifdef CONFIG_IP_ROUTE_VERBOSE
2377 if (IN_DEV_LOG_MARTIANS(in_dev))
2378 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2379 &daddr, &saddr, dev->name);
2383 err = -EHOSTUNREACH;
2396 martian_source_keep_err:
2397 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2401 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2402 u8 tos, struct net_device *dev, bool noref)
2406 int iif = dev->ifindex;
2414 if (!rt_caching(net))
2417 tos &= IPTOS_RT_MASK;
2418 hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2420 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2421 rth = rcu_dereference(rth->dst.rt_next)) {
2422 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2423 ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2424 (rth->rt_route_iif ^ iif) |
2425 (rth->rt_key_tos ^ tos)) == 0 &&
2426 rth->rt_mark == skb->mark &&
2427 net_eq(dev_net(rth->dst.dev), net) &&
2428 !rt_is_expired(rth)) {
2429 ipv4_validate_peer(rth);
2431 dst_use_noref(&rth->dst, jiffies);
2432 skb_dst_set_noref(skb, &rth->dst);
2434 dst_use(&rth->dst, jiffies);
2435 skb_dst_set(skb, &rth->dst);
2437 RT_CACHE_STAT_INC(in_hit);
2441 RT_CACHE_STAT_INC(in_hlist_search);
2445 /* Multicast recognition logic is moved from route cache to here.
2446 The problem was that too many Ethernet cards have broken/missing
2447 hardware multicast filters :-( As result the host on multicasting
2448 network acquires a lot of useless route cache entries, sort of
2449 SDR messages from all the world. Now we try to get rid of them.
2450 Really, provided software IP multicast filter is organized
2451 reasonably (at least, hashed), it does not result in a slowdown
2452 comparing with route cache reject entries.
2453 Note, that multicast routers are not affected, because
2454 route cache entry is created eventually.
2456 if (ipv4_is_multicast(daddr)) {
2457 struct in_device *in_dev = __in_dev_get_rcu(dev);
2460 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2461 ip_hdr(skb)->protocol);
2463 #ifdef CONFIG_IP_MROUTE
2465 (!ipv4_is_local_multicast(daddr) &&
2466 IN_DEV_MFORWARD(in_dev))
2469 int res = ip_route_input_mc(skb, daddr, saddr,
2478 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2482 EXPORT_SYMBOL(ip_route_input_common);
2484 /* called with rcu_read_lock() */
2485 static struct rtable *__mkroute_output(const struct fib_result *res,
2486 const struct flowi4 *fl4,
2487 __be32 orig_daddr, __be32 orig_saddr,
2488 int orig_oif, __u8 orig_rtos,
2489 struct net_device *dev_out,
2492 struct fib_info *fi = res->fi;
2493 struct in_device *in_dev;
2494 u16 type = res->type;
2497 in_dev = __in_dev_get_rcu(dev_out);
2499 return ERR_PTR(-EINVAL);
2501 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2502 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2503 return ERR_PTR(-EINVAL);
2505 if (ipv4_is_lbcast(fl4->daddr))
2506 type = RTN_BROADCAST;
2507 else if (ipv4_is_multicast(fl4->daddr))
2508 type = RTN_MULTICAST;
2509 else if (ipv4_is_zeronet(fl4->daddr))
2510 return ERR_PTR(-EINVAL);
2512 if (dev_out->flags & IFF_LOOPBACK)
2513 flags |= RTCF_LOCAL;
2515 if (type == RTN_BROADCAST) {
2516 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2518 } else if (type == RTN_MULTICAST) {
2519 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2520 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2522 flags &= ~RTCF_LOCAL;
2523 /* If multicast route do not exist use
2524 * default one, but do not gateway in this case.
2527 if (fi && res->prefixlen < 4)
2531 rth = rt_dst_alloc(dev_out,
2532 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2533 IN_DEV_CONF_GET(in_dev, NOXFRM));
2535 return ERR_PTR(-ENOBUFS);
2537 rth->dst.output = ip_output;
2539 rth->rt_key_dst = orig_daddr;
2540 rth->rt_key_src = orig_saddr;
2541 rth->rt_genid = rt_genid(dev_net(dev_out));
2542 rth->rt_flags = flags;
2543 rth->rt_type = type;
2544 rth->rt_key_tos = orig_rtos;
2545 rth->rt_dst = fl4->daddr;
2546 rth->rt_src = fl4->saddr;
2547 rth->rt_route_iif = 0;
2548 rth->rt_iif = orig_oif ? : dev_out->ifindex;
2549 rth->rt_oif = orig_oif;
2550 rth->rt_mark = fl4->flowi4_mark;
2551 rth->rt_gateway = fl4->daddr;
2552 rth->rt_spec_dst= fl4->saddr;
2553 rth->rt_peer_genid = 0;
2554 rt_init_peer(rth, (res->table ?
2555 &res->table->tb_peers :
2556 dev_net(dev_out)->ipv4.peers));
2559 RT_CACHE_STAT_INC(out_slow_tot);
2561 if (flags & RTCF_LOCAL) {
2562 rth->dst.input = ip_local_deliver;
2563 rth->rt_spec_dst = fl4->daddr;
2565 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2566 rth->rt_spec_dst = fl4->saddr;
2567 if (flags & RTCF_LOCAL &&
2568 !(dev_out->flags & IFF_LOOPBACK)) {
2569 rth->dst.output = ip_mc_output;
2570 RT_CACHE_STAT_INC(out_slow_mc);
2572 #ifdef CONFIG_IP_MROUTE
2573 if (type == RTN_MULTICAST) {
2574 if (IN_DEV_MFORWARD(in_dev) &&
2575 !ipv4_is_local_multicast(fl4->daddr)) {
2576 rth->dst.input = ip_mr_input;
2577 rth->dst.output = ip_mc_output;
2583 rt_set_nexthop(rth, fl4, res, fi, type, 0);
2589 * Major route resolver routine.
2590 * called with rcu_read_lock();
2593 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4)
2595 struct net_device *dev_out = NULL;
2596 __u8 tos = RT_FL_TOS(fl4);
2597 unsigned int flags = 0;
2598 struct fib_result res;
2606 #ifdef CONFIG_IP_MULTIPLE_TABLES
2610 orig_daddr = fl4->daddr;
2611 orig_saddr = fl4->saddr;
2612 orig_oif = fl4->flowi4_oif;
2614 fl4->flowi4_iif = net->loopback_dev->ifindex;
2615 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2616 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2617 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2621 rth = ERR_PTR(-EINVAL);
2622 if (ipv4_is_multicast(fl4->saddr) ||
2623 ipv4_is_lbcast(fl4->saddr) ||
2624 ipv4_is_zeronet(fl4->saddr))
2627 /* I removed check for oif == dev_out->oif here.
2628 It was wrong for two reasons:
2629 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2630 is assigned to multiple interfaces.
2631 2. Moreover, we are allowed to send packets with saddr
2632 of another iface. --ANK
2635 if (fl4->flowi4_oif == 0 &&
2636 (ipv4_is_multicast(fl4->daddr) ||
2637 ipv4_is_lbcast(fl4->daddr))) {
2638 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2639 dev_out = __ip_dev_find(net, fl4->saddr, false);
2640 if (dev_out == NULL)
2643 /* Special hack: user can direct multicasts
2644 and limited broadcast via necessary interface
2645 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2646 This hack is not just for fun, it allows
2647 vic,vat and friends to work.
2648 They bind socket to loopback, set ttl to zero
2649 and expect that it will work.
2650 From the viewpoint of routing cache they are broken,
2651 because we are not allowed to build multicast path
2652 with loopback source addr (look, routing cache
2653 cannot know, that ttl is zero, so that packet
2654 will not leave this host and route is valid).
2655 Luckily, this hack is good workaround.
2658 fl4->flowi4_oif = dev_out->ifindex;
2662 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2663 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2664 if (!__ip_dev_find(net, fl4->saddr, false))
2670 if (fl4->flowi4_oif) {
2671 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2672 rth = ERR_PTR(-ENODEV);
2673 if (dev_out == NULL)
2676 /* RACE: Check return value of inet_select_addr instead. */
2677 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2678 rth = ERR_PTR(-ENETUNREACH);
2681 if (ipv4_is_local_multicast(fl4->daddr) ||
2682 ipv4_is_lbcast(fl4->daddr)) {
2684 fl4->saddr = inet_select_addr(dev_out, 0,
2689 if (ipv4_is_multicast(fl4->daddr))
2690 fl4->saddr = inet_select_addr(dev_out, 0,
2692 else if (!fl4->daddr)
2693 fl4->saddr = inet_select_addr(dev_out, 0,
2699 fl4->daddr = fl4->saddr;
2701 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2702 dev_out = net->loopback_dev;
2703 fl4->flowi4_oif = net->loopback_dev->ifindex;
2704 res.type = RTN_LOCAL;
2705 flags |= RTCF_LOCAL;
2709 if (fib_lookup(net, fl4, &res)) {
2712 if (fl4->flowi4_oif) {
2713 /* Apparently, routing tables are wrong. Assume,
2714 that the destination is on link.
2717 Because we are allowed to send to iface
2718 even if it has NO routes and NO assigned
2719 addresses. When oif is specified, routing
2720 tables are looked up with only one purpose:
2721 to catch if destination is gatewayed, rather than
2722 direct. Moreover, if MSG_DONTROUTE is set,
2723 we send packet, ignoring both routing tables
2724 and ifaddr state. --ANK
2727 We could make it even if oif is unknown,
2728 likely IPv6, but we do not.
2731 if (fl4->saddr == 0)
2732 fl4->saddr = inet_select_addr(dev_out, 0,
2734 res.type = RTN_UNICAST;
2737 rth = ERR_PTR(-ENETUNREACH);
2741 if (res.type == RTN_LOCAL) {
2743 if (res.fi->fib_prefsrc)
2744 fl4->saddr = res.fi->fib_prefsrc;
2746 fl4->saddr = fl4->daddr;
2748 dev_out = net->loopback_dev;
2749 fl4->flowi4_oif = dev_out->ifindex;
2751 flags |= RTCF_LOCAL;
2755 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2756 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2757 fib_select_multipath(&res);
2760 if (!res.prefixlen &&
2761 res.table->tb_num_default > 1 &&
2762 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2763 fib_select_default(&res);
2766 fl4->saddr = FIB_RES_PREFSRC(net, res);
2768 dev_out = FIB_RES_DEV(res);
2769 fl4->flowi4_oif = dev_out->ifindex;
2773 rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif,
2774 tos, dev_out, flags);
2778 hash = rt_hash(orig_daddr, orig_saddr, orig_oif,
2779 rt_genid(dev_net(dev_out)));
2780 rth = rt_intern_hash(hash, rth, NULL, orig_oif);
2788 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
2793 if (!rt_caching(net))
2796 hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2799 for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2800 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2801 if (rth->rt_key_dst == flp4->daddr &&
2802 rth->rt_key_src == flp4->saddr &&
2803 rt_is_output_route(rth) &&
2804 rth->rt_oif == flp4->flowi4_oif &&
2805 rth->rt_mark == flp4->flowi4_mark &&
2806 !((rth->rt_key_tos ^ flp4->flowi4_tos) &
2807 (IPTOS_RT_MASK | RTO_ONLINK)) &&
2808 net_eq(dev_net(rth->dst.dev), net) &&
2809 !rt_is_expired(rth)) {
2810 ipv4_validate_peer(rth);
2811 dst_use(&rth->dst, jiffies);
2812 RT_CACHE_STAT_INC(out_hit);
2813 rcu_read_unlock_bh();
2815 flp4->saddr = rth->rt_src;
2817 flp4->daddr = rth->rt_dst;
2820 RT_CACHE_STAT_INC(out_hlist_search);
2822 rcu_read_unlock_bh();
2825 return ip_route_output_slow(net, flp4);
2827 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2829 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2834 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2836 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2838 return mtu ? : dst->dev->mtu;
2841 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2845 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2851 static struct dst_ops ipv4_dst_blackhole_ops = {
2853 .protocol = cpu_to_be16(ETH_P_IP),
2854 .destroy = ipv4_dst_destroy,
2855 .check = ipv4_blackhole_dst_check,
2856 .mtu = ipv4_blackhole_mtu,
2857 .default_advmss = ipv4_default_advmss,
2858 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2859 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2860 .neigh_lookup = ipv4_neigh_lookup,
2863 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2865 struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
2866 struct rtable *ort = (struct rtable *) dst_orig;
2869 struct dst_entry *new = &rt->dst;
2872 new->input = dst_discard;
2873 new->output = dst_discard;
2874 dst_copy_metrics(new, &ort->dst);
2876 new->dev = ort->dst.dev;
2880 rt->rt_key_dst = ort->rt_key_dst;
2881 rt->rt_key_src = ort->rt_key_src;
2882 rt->rt_key_tos = ort->rt_key_tos;
2883 rt->rt_route_iif = ort->rt_route_iif;
2884 rt->rt_iif = ort->rt_iif;
2885 rt->rt_oif = ort->rt_oif;
2886 rt->rt_mark = ort->rt_mark;
2888 rt->rt_genid = rt_genid(net);
2889 rt->rt_flags = ort->rt_flags;
2890 rt->rt_type = ort->rt_type;
2891 rt->rt_dst = ort->rt_dst;
2892 rt->rt_src = ort->rt_src;
2893 rt->rt_gateway = ort->rt_gateway;
2894 rt->rt_spec_dst = ort->rt_spec_dst;
2895 rt_transfer_peer(rt, ort);
2898 atomic_inc(&rt->fi->fib_clntref);
2903 dst_release(dst_orig);
2905 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2908 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2911 struct rtable *rt = __ip_route_output_key(net, flp4);
2916 if (flp4->flowi4_proto)
2917 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2918 flowi4_to_flowi(flp4),
2923 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2925 static int rt_fill_info(struct net *net,
2926 struct sk_buff *skb, u32 pid, u32 seq, int event,
2927 int nowait, unsigned int flags)
2929 struct rtable *rt = skb_rtable(skb);
2931 struct nlmsghdr *nlh;
2932 unsigned long expires = 0;
2933 u32 id = 0, ts = 0, tsage = 0, error;
2935 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2939 r = nlmsg_data(nlh);
2940 r->rtm_family = AF_INET;
2941 r->rtm_dst_len = 32;
2943 r->rtm_tos = rt->rt_key_tos;
2944 r->rtm_table = RT_TABLE_MAIN;
2945 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2946 goto nla_put_failure;
2947 r->rtm_type = rt->rt_type;
2948 r->rtm_scope = RT_SCOPE_UNIVERSE;
2949 r->rtm_protocol = RTPROT_UNSPEC;
2950 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2951 if (rt->rt_flags & RTCF_NOTIFY)
2952 r->rtm_flags |= RTM_F_NOTIFY;
2954 if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2955 goto nla_put_failure;
2956 if (rt->rt_key_src) {
2957 r->rtm_src_len = 32;
2958 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src))
2959 goto nla_put_failure;
2962 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2963 goto nla_put_failure;
2964 #ifdef CONFIG_IP_ROUTE_CLASSID
2965 if (rt->dst.tclassid &&
2966 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2967 goto nla_put_failure;
2969 if (rt_is_input_route(rt)) {
2970 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_spec_dst))
2971 goto nla_put_failure;
2972 } else if (rt->rt_src != rt->rt_key_src) {
2973 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src))
2974 goto nla_put_failure;
2976 if (rt->rt_dst != rt->rt_gateway &&
2977 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2978 goto nla_put_failure;
2980 if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
2981 goto nla_put_failure;
2984 nla_put_be32(skb, RTA_MARK, rt->rt_mark))
2985 goto nla_put_failure;
2987 error = rt->dst.error;
2988 if (rt_has_peer(rt)) {
2989 const struct inet_peer *peer = rt_peer_ptr(rt);
2990 inet_peer_refcheck(peer);
2991 id = atomic_read(&peer->ip_id_count) & 0xffff;
2992 if (peer->tcp_ts_stamp) {
2994 tsage = get_seconds() - peer->tcp_ts_stamp;
2996 expires = ACCESS_ONCE(peer->pmtu_expires);
2998 if (time_before(jiffies, expires))
3005 if (rt_is_input_route(rt)) {
3006 #ifdef CONFIG_IP_MROUTE
3007 __be32 dst = rt->rt_dst;
3009 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
3010 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
3011 int err = ipmr_get_route(net, skb,
3012 rt->rt_src, rt->rt_dst,
3018 goto nla_put_failure;
3020 if (err == -EMSGSIZE)
3021 goto nla_put_failure;
3027 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
3028 goto nla_put_failure;
3031 if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage,
3032 expires, error) < 0)
3033 goto nla_put_failure;
3035 return nlmsg_end(skb, nlh);
3038 nlmsg_cancel(skb, nlh);
3042 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
3044 struct net *net = sock_net(in_skb->sk);
3046 struct nlattr *tb[RTA_MAX+1];
3047 struct rtable *rt = NULL;
3053 struct sk_buff *skb;
3055 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
3059 rtm = nlmsg_data(nlh);
3061 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3067 /* Reserve room for dummy headers, this skb can pass
3068 through good chunk of routing engine.
3070 skb_reset_mac_header(skb);
3071 skb_reset_network_header(skb);
3073 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
3074 ip_hdr(skb)->protocol = IPPROTO_ICMP;
3075 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
3077 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
3078 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
3079 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3080 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3083 struct net_device *dev;
3085 dev = __dev_get_by_index(net, iif);
3091 skb->protocol = htons(ETH_P_IP);
3095 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
3098 rt = skb_rtable(skb);
3099 if (err == 0 && rt->dst.error)
3100 err = -rt->dst.error;
3102 struct flowi4 fl4 = {
3105 .flowi4_tos = rtm->rtm_tos,
3106 .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
3107 .flowi4_mark = mark,
3109 rt = ip_route_output_key(net, &fl4);
3119 skb_dst_set(skb, &rt->dst);
3120 if (rtm->rtm_flags & RTM_F_NOTIFY)
3121 rt->rt_flags |= RTCF_NOTIFY;
3123 err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
3124 RTM_NEWROUTE, 0, 0);
3128 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
3137 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
3144 net = sock_net(skb->sk);
3149 s_idx = idx = cb->args[1];
3150 for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
3151 if (!rt_hash_table[h].chain)
3154 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
3155 rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
3156 if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
3158 if (rt_is_expired(rt))
3160 skb_dst_set_noref(skb, &rt->dst);
3161 if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
3162 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
3163 1, NLM_F_MULTI) <= 0) {
3165 rcu_read_unlock_bh();
3170 rcu_read_unlock_bh();
3179 void ip_rt_multicast_event(struct in_device *in_dev)
3181 rt_cache_flush(dev_net(in_dev->dev), 0);
3184 #ifdef CONFIG_SYSCTL
3185 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
3186 void __user *buffer,
3187 size_t *lenp, loff_t *ppos)
3194 memcpy(&ctl, __ctl, sizeof(ctl));
3195 ctl.data = &flush_delay;
3196 proc_dointvec(&ctl, write, buffer, lenp, ppos);
3198 net = (struct net *)__ctl->extra1;
3199 rt_cache_flush(net, flush_delay);
3206 static ctl_table ipv4_route_table[] = {
3208 .procname = "gc_thresh",
3209 .data = &ipv4_dst_ops.gc_thresh,
3210 .maxlen = sizeof(int),
3212 .proc_handler = proc_dointvec,
3215 .procname = "max_size",
3216 .data = &ip_rt_max_size,
3217 .maxlen = sizeof(int),
3219 .proc_handler = proc_dointvec,
3222 /* Deprecated. Use gc_min_interval_ms */
3224 .procname = "gc_min_interval",
3225 .data = &ip_rt_gc_min_interval,
3226 .maxlen = sizeof(int),
3228 .proc_handler = proc_dointvec_jiffies,
3231 .procname = "gc_min_interval_ms",
3232 .data = &ip_rt_gc_min_interval,
3233 .maxlen = sizeof(int),
3235 .proc_handler = proc_dointvec_ms_jiffies,
3238 .procname = "gc_timeout",
3239 .data = &ip_rt_gc_timeout,
3240 .maxlen = sizeof(int),
3242 .proc_handler = proc_dointvec_jiffies,
3245 .procname = "gc_interval",
3246 .data = &ip_rt_gc_interval,
3247 .maxlen = sizeof(int),
3249 .proc_handler = proc_dointvec_jiffies,
3252 .procname = "redirect_load",
3253 .data = &ip_rt_redirect_load,
3254 .maxlen = sizeof(int),
3256 .proc_handler = proc_dointvec,
3259 .procname = "redirect_number",
3260 .data = &ip_rt_redirect_number,
3261 .maxlen = sizeof(int),
3263 .proc_handler = proc_dointvec,
3266 .procname = "redirect_silence",
3267 .data = &ip_rt_redirect_silence,
3268 .maxlen = sizeof(int),
3270 .proc_handler = proc_dointvec,
3273 .procname = "error_cost",
3274 .data = &ip_rt_error_cost,
3275 .maxlen = sizeof(int),
3277 .proc_handler = proc_dointvec,
3280 .procname = "error_burst",
3281 .data = &ip_rt_error_burst,
3282 .maxlen = sizeof(int),
3284 .proc_handler = proc_dointvec,
3287 .procname = "gc_elasticity",
3288 .data = &ip_rt_gc_elasticity,
3289 .maxlen = sizeof(int),
3291 .proc_handler = proc_dointvec,
3294 .procname = "mtu_expires",
3295 .data = &ip_rt_mtu_expires,
3296 .maxlen = sizeof(int),
3298 .proc_handler = proc_dointvec_jiffies,
3301 .procname = "min_pmtu",
3302 .data = &ip_rt_min_pmtu,
3303 .maxlen = sizeof(int),
3305 .proc_handler = proc_dointvec,
3308 .procname = "min_adv_mss",
3309 .data = &ip_rt_min_advmss,
3310 .maxlen = sizeof(int),
3312 .proc_handler = proc_dointvec,
3317 static struct ctl_table ipv4_route_flush_table[] = {
3319 .procname = "flush",
3320 .maxlen = sizeof(int),
3322 .proc_handler = ipv4_sysctl_rtcache_flush,
3327 static __net_init int sysctl_route_net_init(struct net *net)
3329 struct ctl_table *tbl;
3331 tbl = ipv4_route_flush_table;
3332 if (!net_eq(net, &init_net)) {
3333 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3337 tbl[0].extra1 = net;
3339 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3340 if (net->ipv4.route_hdr == NULL)
3345 if (tbl != ipv4_route_flush_table)
3351 static __net_exit void sysctl_route_net_exit(struct net *net)
3353 struct ctl_table *tbl;
3355 tbl = net->ipv4.route_hdr->ctl_table_arg;
3356 unregister_net_sysctl_table(net->ipv4.route_hdr);
3357 BUG_ON(tbl == ipv4_route_flush_table);
3361 static __net_initdata struct pernet_operations sysctl_route_ops = {
3362 .init = sysctl_route_net_init,
3363 .exit = sysctl_route_net_exit,
3367 static __net_init int rt_genid_init(struct net *net)
3369 get_random_bytes(&net->ipv4.rt_genid,
3370 sizeof(net->ipv4.rt_genid));
3371 get_random_bytes(&net->ipv4.dev_addr_genid,
3372 sizeof(net->ipv4.dev_addr_genid));
3376 static __net_initdata struct pernet_operations rt_genid_ops = {
3377 .init = rt_genid_init,
3380 static int __net_init ipv4_inetpeer_init(struct net *net)
3382 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3386 inet_peer_base_init(bp);
3387 net->ipv4.peers = bp;
3391 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3393 struct inet_peer_base *bp = net->ipv4.peers;
3395 net->ipv4.peers = NULL;
3396 inetpeer_invalidate_tree(bp);
3400 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3401 .init = ipv4_inetpeer_init,
3402 .exit = ipv4_inetpeer_exit,
3405 #ifdef CONFIG_IP_ROUTE_CLASSID
3406 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3407 #endif /* CONFIG_IP_ROUTE_CLASSID */
3409 static __initdata unsigned long rhash_entries;
3410 static int __init set_rhash_entries(char *str)
3417 ret = kstrtoul(str, 0, &rhash_entries);
3423 __setup("rhash_entries=", set_rhash_entries);
3425 int __init ip_rt_init(void)
3429 #ifdef CONFIG_IP_ROUTE_CLASSID
3430 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3432 panic("IP: failed to allocate ip_rt_acct\n");
3435 ipv4_dst_ops.kmem_cachep =
3436 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3437 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3439 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3441 if (dst_entries_init(&ipv4_dst_ops) < 0)
3442 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3444 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3445 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3447 rt_hash_table = (struct rt_hash_bucket *)
3448 alloc_large_system_hash("IP route cache",
3449 sizeof(struct rt_hash_bucket),
3451 (totalram_pages >= 128 * 1024) ?
3457 rhash_entries ? 0 : 512 * 1024);
3458 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3459 rt_hash_lock_init();
3461 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3462 ip_rt_max_size = (rt_hash_mask + 1) * 16;
3467 INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3468 expires_ljiffies = jiffies;
3469 schedule_delayed_work(&expires_work,
3470 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3472 if (ip_rt_proc_init())
3473 pr_err("Unable to create route proc files\n");
3476 xfrm4_init(ip_rt_max_size);
3478 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3480 #ifdef CONFIG_SYSCTL
3481 register_pernet_subsys(&sysctl_route_ops);
3483 register_pernet_subsys(&rt_genid_ops);
3484 register_pernet_subsys(&ipv4_inetpeer_ops);
3488 #ifdef CONFIG_SYSCTL
3490 * We really need to sanitize the damn ipv4 init order, then all
3491 * this nonsense will go away.
3493 void __init ip_static_sysctl_init(void)
3495 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);