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 void ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb);
153 static int rt_garbage_collect(struct dst_ops *ops);
155 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
160 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
166 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
170 static struct dst_ops ipv4_dst_ops = {
172 .protocol = cpu_to_be16(ETH_P_IP),
173 .gc = rt_garbage_collect,
174 .check = ipv4_dst_check,
175 .default_advmss = ipv4_default_advmss,
177 .cow_metrics = ipv4_cow_metrics,
178 .destroy = ipv4_dst_destroy,
179 .ifdown = ipv4_dst_ifdown,
180 .negative_advice = ipv4_negative_advice,
181 .link_failure = ipv4_link_failure,
182 .update_pmtu = ip_rt_update_pmtu,
183 .redirect = ip_do_redirect,
184 .local_out = __ip_local_out,
185 .neigh_lookup = ipv4_neigh_lookup,
188 #define ECN_OR_COST(class) TC_PRIO_##class
190 const __u8 ip_tos2prio[16] = {
192 ECN_OR_COST(BESTEFFORT),
194 ECN_OR_COST(BESTEFFORT),
200 ECN_OR_COST(INTERACTIVE),
202 ECN_OR_COST(INTERACTIVE),
203 TC_PRIO_INTERACTIVE_BULK,
204 ECN_OR_COST(INTERACTIVE_BULK),
205 TC_PRIO_INTERACTIVE_BULK,
206 ECN_OR_COST(INTERACTIVE_BULK)
208 EXPORT_SYMBOL(ip_tos2prio);
214 /* The locking scheme is rather straight forward:
216 * 1) Read-Copy Update protects the buckets of the central route hash.
217 * 2) Only writers remove entries, and they hold the lock
218 * as they look at rtable reference counts.
219 * 3) Only readers acquire references to rtable entries,
220 * they do so with atomic increments and with the
224 struct rt_hash_bucket {
225 struct rtable __rcu *chain;
228 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
229 defined(CONFIG_PROVE_LOCKING)
231 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
232 * The size of this table is a power of two and depends on the number of CPUS.
233 * (on lockdep we have a quite big spinlock_t, so keep the size down there)
235 #ifdef CONFIG_LOCKDEP
236 # define RT_HASH_LOCK_SZ 256
239 # define RT_HASH_LOCK_SZ 4096
241 # define RT_HASH_LOCK_SZ 2048
243 # define RT_HASH_LOCK_SZ 1024
245 # define RT_HASH_LOCK_SZ 512
247 # define RT_HASH_LOCK_SZ 256
251 static spinlock_t *rt_hash_locks;
252 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
254 static __init void rt_hash_lock_init(void)
258 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
261 panic("IP: failed to allocate rt_hash_locks\n");
263 for (i = 0; i < RT_HASH_LOCK_SZ; i++)
264 spin_lock_init(&rt_hash_locks[i]);
267 # define rt_hash_lock_addr(slot) NULL
269 static inline void rt_hash_lock_init(void)
274 static struct rt_hash_bucket *rt_hash_table __read_mostly;
275 static unsigned int rt_hash_mask __read_mostly;
276 static unsigned int rt_hash_log __read_mostly;
278 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
279 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
281 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
284 return jhash_3words((__force u32)daddr, (__force u32)saddr,
289 static inline int rt_genid(struct net *net)
291 return atomic_read(&net->ipv4.rt_genid);
294 #ifdef CONFIG_PROC_FS
295 struct rt_cache_iter_state {
296 struct seq_net_private p;
301 static struct rtable *rt_cache_get_first(struct seq_file *seq)
303 struct rt_cache_iter_state *st = seq->private;
304 struct rtable *r = NULL;
306 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
307 if (!rcu_access_pointer(rt_hash_table[st->bucket].chain))
310 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
312 if (dev_net(r->dst.dev) == seq_file_net(seq) &&
313 r->rt_genid == st->genid)
315 r = rcu_dereference_bh(r->dst.rt_next);
317 rcu_read_unlock_bh();
322 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
325 struct rt_cache_iter_state *st = seq->private;
327 r = rcu_dereference_bh(r->dst.rt_next);
329 rcu_read_unlock_bh();
331 if (--st->bucket < 0)
333 } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain));
335 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
340 static struct rtable *rt_cache_get_next(struct seq_file *seq,
343 struct rt_cache_iter_state *st = seq->private;
344 while ((r = __rt_cache_get_next(seq, r)) != NULL) {
345 if (dev_net(r->dst.dev) != seq_file_net(seq))
347 if (r->rt_genid == st->genid)
353 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
355 struct rtable *r = rt_cache_get_first(seq);
358 while (pos && (r = rt_cache_get_next(seq, r)))
360 return pos ? NULL : r;
363 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
365 struct rt_cache_iter_state *st = seq->private;
367 return rt_cache_get_idx(seq, *pos - 1);
368 st->genid = rt_genid(seq_file_net(seq));
369 return SEQ_START_TOKEN;
372 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
376 if (v == SEQ_START_TOKEN)
377 r = rt_cache_get_first(seq);
379 r = rt_cache_get_next(seq, v);
384 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
386 if (v && v != SEQ_START_TOKEN)
387 rcu_read_unlock_bh();
390 static int rt_cache_seq_show(struct seq_file *seq, void *v)
392 if (v == SEQ_START_TOKEN)
393 seq_printf(seq, "%-127s\n",
394 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
395 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
398 struct rtable *r = v;
401 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
402 "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
403 r->dst.dev ? r->dst.dev->name : "*",
404 (__force u32)r->rt_dst,
405 (__force u32)r->rt_gateway,
406 r->rt_flags, atomic_read(&r->dst.__refcnt),
407 r->dst.__use, 0, (__force u32)r->rt_src,
408 dst_metric_advmss(&r->dst) + 40,
409 dst_metric(&r->dst, RTAX_WINDOW), 0,
413 seq_printf(seq, "%*s\n", 127 - len, "");
418 static const struct seq_operations rt_cache_seq_ops = {
419 .start = rt_cache_seq_start,
420 .next = rt_cache_seq_next,
421 .stop = rt_cache_seq_stop,
422 .show = rt_cache_seq_show,
425 static int rt_cache_seq_open(struct inode *inode, struct file *file)
427 return seq_open_net(inode, file, &rt_cache_seq_ops,
428 sizeof(struct rt_cache_iter_state));
431 static const struct file_operations rt_cache_seq_fops = {
432 .owner = THIS_MODULE,
433 .open = rt_cache_seq_open,
436 .release = seq_release_net,
440 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
445 return SEQ_START_TOKEN;
447 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
448 if (!cpu_possible(cpu))
451 return &per_cpu(rt_cache_stat, cpu);
456 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
460 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
461 if (!cpu_possible(cpu))
464 return &per_cpu(rt_cache_stat, cpu);
470 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
475 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
477 struct rt_cache_stat *st = v;
479 if (v == SEQ_START_TOKEN) {
480 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");
484 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
485 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
486 dst_entries_get_slow(&ipv4_dst_ops),
509 static const struct seq_operations rt_cpu_seq_ops = {
510 .start = rt_cpu_seq_start,
511 .next = rt_cpu_seq_next,
512 .stop = rt_cpu_seq_stop,
513 .show = rt_cpu_seq_show,
517 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
519 return seq_open(file, &rt_cpu_seq_ops);
522 static const struct file_operations rt_cpu_seq_fops = {
523 .owner = THIS_MODULE,
524 .open = rt_cpu_seq_open,
527 .release = seq_release,
530 #ifdef CONFIG_IP_ROUTE_CLASSID
531 static int rt_acct_proc_show(struct seq_file *m, void *v)
533 struct ip_rt_acct *dst, *src;
536 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
540 for_each_possible_cpu(i) {
541 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
542 for (j = 0; j < 256; j++) {
543 dst[j].o_bytes += src[j].o_bytes;
544 dst[j].o_packets += src[j].o_packets;
545 dst[j].i_bytes += src[j].i_bytes;
546 dst[j].i_packets += src[j].i_packets;
550 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
555 static int rt_acct_proc_open(struct inode *inode, struct file *file)
557 return single_open(file, rt_acct_proc_show, NULL);
560 static const struct file_operations rt_acct_proc_fops = {
561 .owner = THIS_MODULE,
562 .open = rt_acct_proc_open,
565 .release = single_release,
569 static int __net_init ip_rt_do_proc_init(struct net *net)
571 struct proc_dir_entry *pde;
573 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
578 pde = proc_create("rt_cache", S_IRUGO,
579 net->proc_net_stat, &rt_cpu_seq_fops);
583 #ifdef CONFIG_IP_ROUTE_CLASSID
584 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
590 #ifdef CONFIG_IP_ROUTE_CLASSID
592 remove_proc_entry("rt_cache", net->proc_net_stat);
595 remove_proc_entry("rt_cache", net->proc_net);
600 static void __net_exit ip_rt_do_proc_exit(struct net *net)
602 remove_proc_entry("rt_cache", net->proc_net_stat);
603 remove_proc_entry("rt_cache", net->proc_net);
604 #ifdef CONFIG_IP_ROUTE_CLASSID
605 remove_proc_entry("rt_acct", net->proc_net);
609 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
610 .init = ip_rt_do_proc_init,
611 .exit = ip_rt_do_proc_exit,
614 static int __init ip_rt_proc_init(void)
616 return register_pernet_subsys(&ip_rt_proc_ops);
620 static inline int ip_rt_proc_init(void)
624 #endif /* CONFIG_PROC_FS */
626 static inline void rt_free(struct rtable *rt)
628 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
631 static inline void rt_drop(struct rtable *rt)
634 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
637 static inline int rt_fast_clean(struct rtable *rth)
639 /* Kill broadcast/multicast entries very aggresively, if they
640 collide in hash table with more useful entries */
641 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
642 rt_is_input_route(rth) && rth->dst.rt_next;
645 static inline int rt_valuable(struct rtable *rth)
647 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
651 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
656 if (atomic_read(&rth->dst.__refcnt))
659 age = jiffies - rth->dst.lastuse;
660 if ((age <= tmo1 && !rt_fast_clean(rth)) ||
661 (age <= tmo2 && rt_valuable(rth)))
667 /* Bits of score are:
669 * 30: not quite useless
670 * 29..0: usage counter
672 static inline u32 rt_score(struct rtable *rt)
674 u32 score = jiffies - rt->dst.lastuse;
676 score = ~score & ~(3<<30);
681 if (rt_is_output_route(rt) ||
682 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
688 static inline bool rt_caching(const struct net *net)
690 return net->ipv4.current_rt_cache_rebuild_count <=
691 net->ipv4.sysctl_rt_cache_rebuild_count;
694 static inline bool compare_hash_inputs(const struct rtable *rt1,
695 const struct rtable *rt2)
697 return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
698 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
699 (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0);
702 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2)
704 return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
705 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
706 (rt1->rt_mark ^ rt2->rt_mark) |
707 (rt1->rt_key_tos ^ rt2->rt_key_tos) |
708 (rt1->rt_route_iif ^ rt2->rt_route_iif) |
709 (rt1->rt_oif ^ rt2->rt_oif)) == 0;
712 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
714 return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev));
717 static inline int rt_is_expired(struct rtable *rth)
719 return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
723 * Perform a full scan of hash table and free all entries.
724 * Can be called by a softirq or a process.
725 * In the later case, we want to be reschedule if necessary
727 static void rt_do_flush(struct net *net, int process_context)
730 struct rtable *rth, *next;
732 for (i = 0; i <= rt_hash_mask; i++) {
733 struct rtable __rcu **pprev;
736 if (process_context && need_resched())
738 rth = rcu_access_pointer(rt_hash_table[i].chain);
742 spin_lock_bh(rt_hash_lock_addr(i));
745 pprev = &rt_hash_table[i].chain;
746 rth = rcu_dereference_protected(*pprev,
747 lockdep_is_held(rt_hash_lock_addr(i)));
750 next = rcu_dereference_protected(rth->dst.rt_next,
751 lockdep_is_held(rt_hash_lock_addr(i)));
754 net_eq(dev_net(rth->dst.dev), net)) {
755 rcu_assign_pointer(*pprev, next);
756 rcu_assign_pointer(rth->dst.rt_next, list);
759 pprev = &rth->dst.rt_next;
764 spin_unlock_bh(rt_hash_lock_addr(i));
766 for (; list; list = next) {
767 next = rcu_dereference_protected(list->dst.rt_next, 1);
774 * While freeing expired entries, we compute average chain length
775 * and standard deviation, using fixed-point arithmetic.
776 * This to have an estimation of rt_chain_length_max
777 * rt_chain_length_max = max(elasticity, AVG + 4*SD)
778 * We use 3 bits for frational part, and 29 (or 61) for magnitude.
782 #define ONE (1UL << FRACT_BITS)
785 * Given a hash chain and an item in this hash chain,
786 * find if a previous entry has the same hash_inputs
787 * (but differs on tos, mark or oif)
788 * Returns 0 if an alias is found.
789 * Returns ONE if rth has no alias before itself.
791 static int has_noalias(const struct rtable *head, const struct rtable *rth)
793 const struct rtable *aux = head;
796 if (compare_hash_inputs(aux, rth))
798 aux = rcu_dereference_protected(aux->dst.rt_next, 1);
803 static void rt_check_expire(void)
805 static unsigned int rover;
806 unsigned int i = rover, goal;
808 struct rtable __rcu **rthp;
809 unsigned long samples = 0;
810 unsigned long sum = 0, sum2 = 0;
814 delta = jiffies - expires_ljiffies;
815 expires_ljiffies = jiffies;
816 mult = ((u64)delta) << rt_hash_log;
817 if (ip_rt_gc_timeout > 1)
818 do_div(mult, ip_rt_gc_timeout);
819 goal = (unsigned int)mult;
820 if (goal > rt_hash_mask)
821 goal = rt_hash_mask + 1;
822 for (; goal > 0; goal--) {
823 unsigned long tmo = ip_rt_gc_timeout;
824 unsigned long length;
826 i = (i + 1) & rt_hash_mask;
827 rthp = &rt_hash_table[i].chain;
834 if (rcu_dereference_raw(*rthp) == NULL)
837 spin_lock_bh(rt_hash_lock_addr(i));
838 while ((rth = rcu_dereference_protected(*rthp,
839 lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) {
840 prefetch(rth->dst.rt_next);
841 if (rt_is_expired(rth) ||
842 rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
843 *rthp = rth->dst.rt_next;
848 /* We only count entries on a chain with equal
849 * hash inputs once so that entries for
850 * different QOS levels, and other non-hash
851 * input attributes don't unfairly skew the
855 rthp = &rth->dst.rt_next;
856 length += has_noalias(rt_hash_table[i].chain, rth);
858 spin_unlock_bh(rt_hash_lock_addr(i));
860 sum2 += length*length;
863 unsigned long avg = sum / samples;
864 unsigned long sd = int_sqrt(sum2 / samples - avg*avg);
865 rt_chain_length_max = max_t(unsigned long,
867 (avg + 4*sd) >> FRACT_BITS);
873 * rt_worker_func() is run in process context.
874 * we call rt_check_expire() to scan part of the hash table
876 static void rt_worker_func(struct work_struct *work)
879 schedule_delayed_work(&expires_work, ip_rt_gc_interval);
883 * Perturbation of rt_genid by a small quantity [1..256]
884 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
885 * many times (2^24) without giving recent rt_genid.
886 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
888 static void rt_cache_invalidate(struct net *net)
890 unsigned char shuffle;
892 get_random_bytes(&shuffle, sizeof(shuffle));
893 atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
897 * delay < 0 : invalidate cache (fast : entries will be deleted later)
898 * delay >= 0 : invalidate & flush cache (can be long)
900 void rt_cache_flush(struct net *net, int delay)
902 rt_cache_invalidate(net);
904 rt_do_flush(net, !in_softirq());
907 /* Flush previous cache invalidated entries from the cache */
908 void rt_cache_flush_batch(struct net *net)
910 rt_do_flush(net, !in_softirq());
913 static void rt_emergency_hash_rebuild(struct net *net)
915 net_warn_ratelimited("Route hash chain too long!\n");
916 rt_cache_invalidate(net);
920 Short description of GC goals.
922 We want to build algorithm, which will keep routing cache
923 at some equilibrium point, when number of aged off entries
924 is kept approximately equal to newly generated ones.
926 Current expiration strength is variable "expire".
927 We try to adjust it dynamically, so that if networking
928 is idle expires is large enough to keep enough of warm entries,
929 and when load increases it reduces to limit cache size.
932 static int rt_garbage_collect(struct dst_ops *ops)
934 static unsigned long expire = RT_GC_TIMEOUT;
935 static unsigned long last_gc;
937 static int equilibrium;
939 struct rtable __rcu **rthp;
940 unsigned long now = jiffies;
942 int entries = dst_entries_get_fast(&ipv4_dst_ops);
945 * Garbage collection is pretty expensive,
946 * do not make it too frequently.
949 RT_CACHE_STAT_INC(gc_total);
951 if (now - last_gc < ip_rt_gc_min_interval &&
952 entries < ip_rt_max_size) {
953 RT_CACHE_STAT_INC(gc_ignored);
957 entries = dst_entries_get_slow(&ipv4_dst_ops);
958 /* Calculate number of entries, which we want to expire now. */
959 goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
961 if (equilibrium < ipv4_dst_ops.gc_thresh)
962 equilibrium = ipv4_dst_ops.gc_thresh;
963 goal = entries - equilibrium;
965 equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
966 goal = entries - equilibrium;
969 /* We are in dangerous area. Try to reduce cache really
972 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
973 equilibrium = entries - goal;
976 if (now - last_gc >= ip_rt_gc_min_interval)
987 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
988 unsigned long tmo = expire;
990 k = (k + 1) & rt_hash_mask;
991 rthp = &rt_hash_table[k].chain;
992 spin_lock_bh(rt_hash_lock_addr(k));
993 while ((rth = rcu_dereference_protected(*rthp,
994 lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
995 if (!rt_is_expired(rth) &&
996 !rt_may_expire(rth, tmo, expire)) {
998 rthp = &rth->dst.rt_next;
1001 *rthp = rth->dst.rt_next;
1005 spin_unlock_bh(rt_hash_lock_addr(k));
1014 /* Goal is not achieved. We stop process if:
1016 - if expire reduced to zero. Otherwise, expire is halfed.
1017 - if table is not full.
1018 - if we are called from interrupt.
1019 - jiffies check is just fallback/debug loop breaker.
1020 We will not spin here for long time in any case.
1023 RT_CACHE_STAT_INC(gc_goal_miss);
1030 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1032 } while (!in_softirq() && time_before_eq(jiffies, now));
1034 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1036 if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
1038 net_warn_ratelimited("dst cache overflow\n");
1039 RT_CACHE_STAT_INC(gc_dst_overflow);
1043 expire += ip_rt_gc_min_interval;
1044 if (expire > ip_rt_gc_timeout ||
1045 dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
1046 dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
1047 expire = ip_rt_gc_timeout;
1052 * Returns number of entries in a hash chain that have different hash_inputs
1054 static int slow_chain_length(const struct rtable *head)
1057 const struct rtable *rth = head;
1060 length += has_noalias(head, rth);
1061 rth = rcu_dereference_protected(rth->dst.rt_next, 1);
1063 return length >> FRACT_BITS;
1066 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
1067 struct sk_buff *skb,
1070 struct net_device *dev = dst->dev;
1071 const __be32 *pkey = daddr;
1072 const struct rtable *rt;
1073 struct neighbour *n;
1075 rt = (const struct rtable *) dst;
1077 pkey = (const __be32 *) &rt->rt_gateway;
1079 pkey = &ip_hdr(skb)->daddr;
1081 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
1084 return neigh_create(&arp_tbl, pkey, dev);
1087 static struct rtable *rt_intern_hash(unsigned int hash, struct rtable *rt,
1088 struct sk_buff *skb, int ifindex)
1090 struct rtable *rth, *cand;
1091 struct rtable __rcu **rthp, **candp;
1098 min_score = ~(u32)0;
1103 if (!rt_caching(dev_net(rt->dst.dev)) || (rt->dst.flags & DST_NOCACHE)) {
1105 * If we're not caching, just tell the caller we
1106 * were successful and don't touch the route. The
1107 * caller hold the sole reference to the cache entry, and
1108 * it will be released when the caller is done with it.
1109 * If we drop it here, the callers have no way to resolve routes
1110 * when we're not caching. Instead, just point *rp at rt, so
1111 * the caller gets a single use out of the route
1112 * Note that we do rt_free on this new route entry, so that
1113 * once its refcount hits zero, we are still able to reap it
1115 * Note: To avoid expensive rcu stuff for this uncached dst,
1116 * we set DST_NOCACHE so that dst_release() can free dst without
1117 * waiting a grace period.
1120 rt->dst.flags |= DST_NOCACHE;
1124 rthp = &rt_hash_table[hash].chain;
1126 spin_lock_bh(rt_hash_lock_addr(hash));
1127 while ((rth = rcu_dereference_protected(*rthp,
1128 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1129 if (rt_is_expired(rth)) {
1130 *rthp = rth->dst.rt_next;
1134 if (compare_keys(rth, rt) && compare_netns(rth, rt)) {
1136 *rthp = rth->dst.rt_next;
1138 * Since lookup is lockfree, the deletion
1139 * must be visible to another weakly ordered CPU before
1140 * the insertion at the start of the hash chain.
1142 rcu_assign_pointer(rth->dst.rt_next,
1143 rt_hash_table[hash].chain);
1145 * Since lookup is lockfree, the update writes
1146 * must be ordered for consistency on SMP.
1148 rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1150 dst_use(&rth->dst, now);
1151 spin_unlock_bh(rt_hash_lock_addr(hash));
1155 skb_dst_set(skb, &rth->dst);
1159 if (!atomic_read(&rth->dst.__refcnt)) {
1160 u32 score = rt_score(rth);
1162 if (score <= min_score) {
1171 rthp = &rth->dst.rt_next;
1175 /* ip_rt_gc_elasticity used to be average length of chain
1176 * length, when exceeded gc becomes really aggressive.
1178 * The second limit is less certain. At the moment it allows
1179 * only 2 entries per bucket. We will see.
1181 if (chain_length > ip_rt_gc_elasticity) {
1182 *candp = cand->dst.rt_next;
1186 if (chain_length > rt_chain_length_max &&
1187 slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
1188 struct net *net = dev_net(rt->dst.dev);
1189 int num = ++net->ipv4.current_rt_cache_rebuild_count;
1190 if (!rt_caching(net)) {
1191 pr_warn("%s: %d rebuilds is over limit, route caching disabled\n",
1192 rt->dst.dev->name, num);
1194 rt_emergency_hash_rebuild(net);
1195 spin_unlock_bh(rt_hash_lock_addr(hash));
1197 hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1198 ifindex, rt_genid(net));
1203 rt->dst.rt_next = rt_hash_table[hash].chain;
1206 * Since lookup is lockfree, we must make sure
1207 * previous writes to rt are committed to memory
1208 * before making rt visible to other CPUS.
1210 rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1212 spin_unlock_bh(rt_hash_lock_addr(hash));
1216 skb_dst_set(skb, &rt->dst);
1221 * Peer allocation may fail only in serious out-of-memory conditions. However
1222 * we still can generate some output.
1223 * Random ID selection looks a bit dangerous because we have no chances to
1224 * select ID being unique in a reasonable period of time.
1225 * But broken packet identifier may be better than no packet at all.
1227 static void ip_select_fb_ident(struct iphdr *iph)
1229 static DEFINE_SPINLOCK(ip_fb_id_lock);
1230 static u32 ip_fallback_id;
1233 spin_lock_bh(&ip_fb_id_lock);
1234 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1235 iph->id = htons(salt & 0xFFFF);
1236 ip_fallback_id = salt;
1237 spin_unlock_bh(&ip_fb_id_lock);
1240 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1242 struct net *net = dev_net(dst->dev);
1243 struct inet_peer *peer;
1245 peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
1247 iph->id = htons(inet_getid(peer, more));
1252 ip_select_fb_ident(iph);
1254 EXPORT_SYMBOL(__ip_select_ident);
1256 static void rt_del(unsigned int hash, struct rtable *rt)
1258 struct rtable __rcu **rthp;
1261 rthp = &rt_hash_table[hash].chain;
1262 spin_lock_bh(rt_hash_lock_addr(hash));
1264 while ((aux = rcu_dereference_protected(*rthp,
1265 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1266 if (aux == rt || rt_is_expired(aux)) {
1267 *rthp = aux->dst.rt_next;
1271 rthp = &aux->dst.rt_next;
1273 spin_unlock_bh(rt_hash_lock_addr(hash));
1276 static void ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb)
1278 const struct iphdr *iph = (const struct iphdr *) skb->data;
1279 __be32 new_gw = icmp_hdr(skb)->un.gateway;
1280 __be32 old_gw = ip_hdr(skb)->saddr;
1281 struct net_device *dev = skb->dev;
1282 __be32 daddr = iph->daddr;
1283 __be32 saddr = iph->saddr;
1284 struct in_device *in_dev;
1285 struct neighbour *n;
1289 switch (icmp_hdr(skb)->code & 7) {
1290 case ICMP_REDIR_NET:
1291 case ICMP_REDIR_NETTOS:
1292 case ICMP_REDIR_HOST:
1293 case ICMP_REDIR_HOSTTOS:
1300 rt = (struct rtable *) dst;
1301 if (rt->rt_gateway != old_gw)
1304 in_dev = __in_dev_get_rcu(dev);
1309 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1310 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1311 ipv4_is_zeronet(new_gw))
1312 goto reject_redirect;
1314 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1315 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1316 goto reject_redirect;
1317 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1318 goto reject_redirect;
1320 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1321 goto reject_redirect;
1324 n = ipv4_neigh_lookup(dst, NULL, &new_gw);
1326 if (!(n->nud_state & NUD_VALID)) {
1327 neigh_event_send(n, NULL);
1329 rt->rt_gateway = new_gw;
1330 rt->rt_flags |= RTCF_REDIRECTED;
1331 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
1338 #ifdef CONFIG_IP_ROUTE_VERBOSE
1339 if (IN_DEV_LOG_MARTIANS(in_dev))
1340 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
1341 " Advised path = %pI4 -> %pI4\n",
1342 &old_gw, dev->name, &new_gw,
1348 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1350 struct rtable *rt = (struct rtable *)dst;
1351 struct dst_entry *ret = dst;
1354 if (dst->obsolete > 0) {
1357 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
1359 unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1361 rt_genid(dev_net(dst->dev)));
1371 * 1. The first ip_rt_redirect_number redirects are sent
1372 * with exponential backoff, then we stop sending them at all,
1373 * assuming that the host ignores our redirects.
1374 * 2. If we did not see packets requiring redirects
1375 * during ip_rt_redirect_silence, we assume that the host
1376 * forgot redirected route and start to send redirects again.
1378 * This algorithm is much cheaper and more intelligent than dumb load limiting
1381 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1382 * and "frag. need" (breaks PMTU discovery) in icmp.c.
1385 void ip_rt_send_redirect(struct sk_buff *skb)
1387 struct rtable *rt = skb_rtable(skb);
1388 struct in_device *in_dev;
1389 struct inet_peer *peer;
1394 in_dev = __in_dev_get_rcu(rt->dst.dev);
1395 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1399 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1402 net = dev_net(rt->dst.dev);
1403 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
1405 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1409 /* No redirected packets during ip_rt_redirect_silence;
1410 * reset the algorithm.
1412 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1413 peer->rate_tokens = 0;
1415 /* Too many ignored redirects; do not send anything
1416 * set dst.rate_last to the last seen redirected packet.
1418 if (peer->rate_tokens >= ip_rt_redirect_number) {
1419 peer->rate_last = jiffies;
1423 /* Check for load limit; set rate_last to the latest sent
1426 if (peer->rate_tokens == 0 ||
1429 (ip_rt_redirect_load << peer->rate_tokens)))) {
1430 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1431 peer->rate_last = jiffies;
1432 ++peer->rate_tokens;
1433 #ifdef CONFIG_IP_ROUTE_VERBOSE
1435 peer->rate_tokens == ip_rt_redirect_number)
1436 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
1437 &ip_hdr(skb)->saddr, rt->rt_iif,
1438 &rt->rt_dst, &rt->rt_gateway);
1445 static int ip_error(struct sk_buff *skb)
1447 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
1448 struct rtable *rt = skb_rtable(skb);
1449 struct inet_peer *peer;
1455 net = dev_net(rt->dst.dev);
1456 if (!IN_DEV_FORWARD(in_dev)) {
1457 switch (rt->dst.error) {
1459 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
1463 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
1469 switch (rt->dst.error) {
1474 code = ICMP_HOST_UNREACH;
1477 code = ICMP_NET_UNREACH;
1478 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
1481 code = ICMP_PKT_FILTERED;
1485 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
1490 peer->rate_tokens += now - peer->rate_last;
1491 if (peer->rate_tokens > ip_rt_error_burst)
1492 peer->rate_tokens = ip_rt_error_burst;
1493 peer->rate_last = now;
1494 if (peer->rate_tokens >= ip_rt_error_cost)
1495 peer->rate_tokens -= ip_rt_error_cost;
1501 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1503 out: kfree_skb(skb);
1507 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1509 struct rtable *rt = (struct rtable *) dst;
1513 if (mtu < ip_rt_min_pmtu)
1514 mtu = ip_rt_min_pmtu;
1517 dst_set_expires(&rt->dst, ip_rt_mtu_expires);
1520 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1521 int oif, u32 mark, u8 protocol, int flow_flags)
1523 const struct iphdr *iph = (const struct iphdr *)skb->data;
1527 flowi4_init_output(&fl4, oif, mark, RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
1528 protocol, flow_flags,
1529 iph->daddr, iph->saddr, 0, 0);
1530 rt = __ip_route_output_key(net, &fl4);
1532 ip_rt_update_pmtu(&rt->dst, mtu);
1536 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1538 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1540 const struct inet_sock *inet = inet_sk(sk);
1542 return ipv4_update_pmtu(skb, sock_net(sk), mtu,
1543 sk->sk_bound_dev_if, sk->sk_mark,
1544 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
1545 inet_sk_flowi_flags(sk));
1547 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1549 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1550 int oif, u32 mark, u8 protocol, int flow_flags)
1552 const struct iphdr *iph = (const struct iphdr *)skb->data;
1556 flowi4_init_output(&fl4, oif, mark, RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
1557 protocol, flow_flags, iph->daddr, iph->saddr, 0, 0);
1558 rt = __ip_route_output_key(net, &fl4);
1560 ip_do_redirect(&rt->dst, skb);
1564 EXPORT_SYMBOL_GPL(ipv4_redirect);
1566 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1568 const struct inet_sock *inet = inet_sk(sk);
1570 return ipv4_redirect(skb, sock_net(sk), sk->sk_bound_dev_if,
1572 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
1573 inet_sk_flowi_flags(sk));
1575 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1577 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1579 struct rtable *rt = (struct rtable *) dst;
1581 if (rt_is_expired(rt))
1586 static void ipv4_dst_destroy(struct dst_entry *dst)
1588 struct rtable *rt = (struct rtable *) dst;
1591 fib_info_put(rt->fi);
1597 static void ipv4_link_failure(struct sk_buff *skb)
1601 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1603 rt = skb_rtable(skb);
1605 dst_set_expires(&rt->dst, 0);
1608 static int ip_rt_bug(struct sk_buff *skb)
1610 pr_debug("%s: %pI4 -> %pI4, %s\n",
1611 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1612 skb->dev ? skb->dev->name : "?");
1619 We do not cache source address of outgoing interface,
1620 because it is used only by IP RR, TS and SRR options,
1621 so that it out of fast path.
1623 BTW remember: "addr" is allowed to be not aligned
1627 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1631 if (rt_is_output_route(rt))
1632 src = ip_hdr(skb)->saddr;
1634 struct fib_result res;
1640 memset(&fl4, 0, sizeof(fl4));
1641 fl4.daddr = iph->daddr;
1642 fl4.saddr = iph->saddr;
1643 fl4.flowi4_tos = RT_TOS(iph->tos);
1644 fl4.flowi4_oif = rt->dst.dev->ifindex;
1645 fl4.flowi4_iif = skb->dev->ifindex;
1646 fl4.flowi4_mark = skb->mark;
1649 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1650 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1652 src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1656 memcpy(addr, &src, 4);
1659 #ifdef CONFIG_IP_ROUTE_CLASSID
1660 static void set_class_tag(struct rtable *rt, u32 tag)
1662 if (!(rt->dst.tclassid & 0xFFFF))
1663 rt->dst.tclassid |= tag & 0xFFFF;
1664 if (!(rt->dst.tclassid & 0xFFFF0000))
1665 rt->dst.tclassid |= tag & 0xFFFF0000;
1669 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1671 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1674 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1676 if (advmss > 65535 - 40)
1677 advmss = 65535 - 40;
1682 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1684 const struct rtable *rt = (const struct rtable *) dst;
1685 unsigned int mtu = rt->rt_pmtu;
1687 if (mtu && time_after_eq(jiffies, rt->dst.expires))
1691 mtu = dst_metric_raw(dst, RTAX_MTU);
1693 if (mtu && rt_is_output_route(rt))
1696 mtu = dst->dev->mtu;
1698 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1700 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1704 if (mtu > IP_MAX_MTU)
1710 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1711 struct fib_info *fi)
1713 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1715 atomic_inc(&fi->fib_clntref);
1717 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1720 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1721 const struct fib_result *res,
1722 struct fib_info *fi, u16 type, u32 itag)
1725 if (FIB_RES_GW(*res) &&
1726 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1727 rt->rt_gateway = FIB_RES_GW(*res);
1728 rt_init_metrics(rt, fl4, fi);
1729 #ifdef CONFIG_IP_ROUTE_CLASSID
1730 rt->dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1734 #ifdef CONFIG_IP_ROUTE_CLASSID
1735 #ifdef CONFIG_IP_MULTIPLE_TABLES
1736 set_class_tag(rt, fib_rules_tclass(res));
1738 set_class_tag(rt, itag);
1742 static struct rtable *rt_dst_alloc(struct net_device *dev,
1743 bool nopolicy, bool noxfrm)
1745 return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
1747 (nopolicy ? DST_NOPOLICY : 0) |
1748 (noxfrm ? DST_NOXFRM : 0));
1751 /* called in rcu_read_lock() section */
1752 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1753 u8 tos, struct net_device *dev, int our)
1757 struct in_device *in_dev = __in_dev_get_rcu(dev);
1761 /* Primary sanity checks. */
1766 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1767 skb->protocol != htons(ETH_P_IP))
1770 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1771 if (ipv4_is_loopback(saddr))
1774 if (ipv4_is_zeronet(saddr)) {
1775 if (!ipv4_is_local_multicast(daddr))
1778 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1783 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1784 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
1788 #ifdef CONFIG_IP_ROUTE_CLASSID
1789 rth->dst.tclassid = itag;
1791 rth->dst.output = ip_rt_bug;
1793 rth->rt_key_dst = daddr;
1794 rth->rt_key_src = saddr;
1795 rth->rt_genid = rt_genid(dev_net(dev));
1796 rth->rt_flags = RTCF_MULTICAST;
1797 rth->rt_type = RTN_MULTICAST;
1798 rth->rt_key_tos = tos;
1799 rth->rt_dst = daddr;
1800 rth->rt_src = saddr;
1801 rth->rt_route_iif = dev->ifindex;
1802 rth->rt_iif = dev->ifindex;
1804 rth->rt_mark = skb->mark;
1806 rth->rt_gateway = daddr;
1809 rth->dst.input= ip_local_deliver;
1810 rth->rt_flags |= RTCF_LOCAL;
1813 #ifdef CONFIG_IP_MROUTE
1814 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1815 rth->dst.input = ip_mr_input;
1817 RT_CACHE_STAT_INC(in_slow_mc);
1819 hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
1820 rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
1821 return IS_ERR(rth) ? PTR_ERR(rth) : 0;
1832 static void ip_handle_martian_source(struct net_device *dev,
1833 struct in_device *in_dev,
1834 struct sk_buff *skb,
1838 RT_CACHE_STAT_INC(in_martian_src);
1839 #ifdef CONFIG_IP_ROUTE_VERBOSE
1840 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1842 * RFC1812 recommendation, if source is martian,
1843 * the only hint is MAC header.
1845 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1846 &daddr, &saddr, dev->name);
1847 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1848 print_hex_dump(KERN_WARNING, "ll header: ",
1849 DUMP_PREFIX_OFFSET, 16, 1,
1850 skb_mac_header(skb),
1851 dev->hard_header_len, true);
1857 /* called in rcu_read_lock() section */
1858 static int __mkroute_input(struct sk_buff *skb,
1859 const struct fib_result *res,
1860 struct in_device *in_dev,
1861 __be32 daddr, __be32 saddr, u32 tos,
1862 struct rtable **result)
1866 struct in_device *out_dev;
1867 unsigned int flags = 0;
1870 /* get a working reference to the output device */
1871 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1872 if (out_dev == NULL) {
1873 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1878 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1879 in_dev->dev, in_dev, &itag);
1881 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1888 flags |= RTCF_DIRECTSRC;
1890 if (out_dev == in_dev && err &&
1891 (IN_DEV_SHARED_MEDIA(out_dev) ||
1892 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1893 flags |= RTCF_DOREDIRECT;
1895 if (skb->protocol != htons(ETH_P_IP)) {
1896 /* Not IP (i.e. ARP). Do not create route, if it is
1897 * invalid for proxy arp. DNAT routes are always valid.
1899 * Proxy arp feature have been extended to allow, ARP
1900 * replies back to the same interface, to support
1901 * Private VLAN switch technologies. See arp.c.
1903 if (out_dev == in_dev &&
1904 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1910 rth = rt_dst_alloc(out_dev->dev,
1911 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1912 IN_DEV_CONF_GET(out_dev, NOXFRM));
1918 rth->rt_key_dst = daddr;
1919 rth->rt_key_src = saddr;
1920 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
1921 rth->rt_flags = flags;
1922 rth->rt_type = res->type;
1923 rth->rt_key_tos = tos;
1924 rth->rt_dst = daddr;
1925 rth->rt_src = saddr;
1926 rth->rt_route_iif = in_dev->dev->ifindex;
1927 rth->rt_iif = in_dev->dev->ifindex;
1929 rth->rt_mark = skb->mark;
1931 rth->rt_gateway = daddr;
1934 rth->dst.input = ip_forward;
1935 rth->dst.output = ip_output;
1937 rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
1945 static int ip_mkroute_input(struct sk_buff *skb,
1946 struct fib_result *res,
1947 const struct flowi4 *fl4,
1948 struct in_device *in_dev,
1949 __be32 daddr, __be32 saddr, u32 tos)
1951 struct rtable *rth = NULL;
1955 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1956 if (res->fi && res->fi->fib_nhs > 1)
1957 fib_select_multipath(res);
1960 /* create a routing cache entry */
1961 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1965 /* put it into the cache */
1966 hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
1967 rt_genid(dev_net(rth->dst.dev)));
1968 rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
1970 return PTR_ERR(rth);
1975 * NOTE. We drop all the packets that has local source
1976 * addresses, because every properly looped back packet
1977 * must have correct destination already attached by output routine.
1979 * Such approach solves two big problems:
1980 * 1. Not simplex devices are handled properly.
1981 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1982 * called with rcu_read_lock()
1985 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1986 u8 tos, struct net_device *dev)
1988 struct fib_result res;
1989 struct in_device *in_dev = __in_dev_get_rcu(dev);
1991 unsigned int flags = 0;
1996 struct net *net = dev_net(dev);
1998 /* IP on this device is disabled. */
2003 /* Check for the most weird martians, which can be not detected
2007 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2008 goto martian_source;
2010 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2013 /* Accept zero addresses only to limited broadcast;
2014 * I even do not know to fix it or not. Waiting for complains :-)
2016 if (ipv4_is_zeronet(saddr))
2017 goto martian_source;
2019 if (ipv4_is_zeronet(daddr))
2020 goto martian_destination;
2022 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
2023 if (ipv4_is_loopback(daddr))
2024 goto martian_destination;
2026 if (ipv4_is_loopback(saddr))
2027 goto martian_source;
2031 * Now we are ready to route packet.
2034 fl4.flowi4_iif = dev->ifindex;
2035 fl4.flowi4_mark = skb->mark;
2036 fl4.flowi4_tos = tos;
2037 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2040 err = fib_lookup(net, &fl4, &res);
2044 RT_CACHE_STAT_INC(in_slow_tot);
2046 if (res.type == RTN_BROADCAST)
2049 if (res.type == RTN_LOCAL) {
2050 err = fib_validate_source(skb, saddr, daddr, tos,
2051 net->loopback_dev->ifindex,
2052 dev, in_dev, &itag);
2054 goto martian_source_keep_err;
2056 flags |= RTCF_DIRECTSRC;
2060 if (!IN_DEV_FORWARD(in_dev))
2062 if (res.type != RTN_UNICAST)
2063 goto martian_destination;
2065 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2069 if (skb->protocol != htons(ETH_P_IP))
2072 if (!ipv4_is_zeronet(saddr)) {
2073 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2076 goto martian_source_keep_err;
2078 flags |= RTCF_DIRECTSRC;
2080 flags |= RTCF_BROADCAST;
2081 res.type = RTN_BROADCAST;
2082 RT_CACHE_STAT_INC(in_brd);
2085 rth = rt_dst_alloc(net->loopback_dev,
2086 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2090 rth->dst.input= ip_local_deliver;
2091 rth->dst.output= ip_rt_bug;
2092 #ifdef CONFIG_IP_ROUTE_CLASSID
2093 rth->dst.tclassid = itag;
2096 rth->rt_key_dst = daddr;
2097 rth->rt_key_src = saddr;
2098 rth->rt_genid = rt_genid(net);
2099 rth->rt_flags = flags|RTCF_LOCAL;
2100 rth->rt_type = res.type;
2101 rth->rt_key_tos = tos;
2102 rth->rt_dst = daddr;
2103 rth->rt_src = saddr;
2104 rth->rt_route_iif = dev->ifindex;
2105 rth->rt_iif = dev->ifindex;
2107 rth->rt_mark = skb->mark;
2109 rth->rt_gateway = daddr;
2111 if (res.type == RTN_UNREACHABLE) {
2112 rth->dst.input= ip_error;
2113 rth->dst.error= -err;
2114 rth->rt_flags &= ~RTCF_LOCAL;
2116 hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2117 rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2124 RT_CACHE_STAT_INC(in_no_route);
2125 res.type = RTN_UNREACHABLE;
2131 * Do not cache martian addresses: they should be logged (RFC1812)
2133 martian_destination:
2134 RT_CACHE_STAT_INC(in_martian_dst);
2135 #ifdef CONFIG_IP_ROUTE_VERBOSE
2136 if (IN_DEV_LOG_MARTIANS(in_dev))
2137 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2138 &daddr, &saddr, dev->name);
2151 martian_source_keep_err:
2152 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2156 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2157 u8 tos, struct net_device *dev, bool noref)
2161 int iif = dev->ifindex;
2169 if (!rt_caching(net))
2172 tos &= IPTOS_RT_MASK;
2173 hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2175 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2176 rth = rcu_dereference(rth->dst.rt_next)) {
2177 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2178 ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2179 (rth->rt_route_iif ^ iif) |
2180 (rth->rt_key_tos ^ tos)) == 0 &&
2181 rth->rt_mark == skb->mark &&
2182 net_eq(dev_net(rth->dst.dev), net) &&
2183 !rt_is_expired(rth)) {
2185 dst_use_noref(&rth->dst, jiffies);
2186 skb_dst_set_noref(skb, &rth->dst);
2188 dst_use(&rth->dst, jiffies);
2189 skb_dst_set(skb, &rth->dst);
2191 RT_CACHE_STAT_INC(in_hit);
2195 RT_CACHE_STAT_INC(in_hlist_search);
2199 /* Multicast recognition logic is moved from route cache to here.
2200 The problem was that too many Ethernet cards have broken/missing
2201 hardware multicast filters :-( As result the host on multicasting
2202 network acquires a lot of useless route cache entries, sort of
2203 SDR messages from all the world. Now we try to get rid of them.
2204 Really, provided software IP multicast filter is organized
2205 reasonably (at least, hashed), it does not result in a slowdown
2206 comparing with route cache reject entries.
2207 Note, that multicast routers are not affected, because
2208 route cache entry is created eventually.
2210 if (ipv4_is_multicast(daddr)) {
2211 struct in_device *in_dev = __in_dev_get_rcu(dev);
2214 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2215 ip_hdr(skb)->protocol);
2217 #ifdef CONFIG_IP_MROUTE
2219 (!ipv4_is_local_multicast(daddr) &&
2220 IN_DEV_MFORWARD(in_dev))
2223 int res = ip_route_input_mc(skb, daddr, saddr,
2232 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2236 EXPORT_SYMBOL(ip_route_input_common);
2238 /* called with rcu_read_lock() */
2239 static struct rtable *__mkroute_output(const struct fib_result *res,
2240 const struct flowi4 *fl4,
2241 __be32 orig_daddr, __be32 orig_saddr,
2242 int orig_oif, __u8 orig_rtos,
2243 struct net_device *dev_out,
2246 struct fib_info *fi = res->fi;
2247 struct in_device *in_dev;
2248 u16 type = res->type;
2251 in_dev = __in_dev_get_rcu(dev_out);
2253 return ERR_PTR(-EINVAL);
2255 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2256 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2257 return ERR_PTR(-EINVAL);
2259 if (ipv4_is_lbcast(fl4->daddr))
2260 type = RTN_BROADCAST;
2261 else if (ipv4_is_multicast(fl4->daddr))
2262 type = RTN_MULTICAST;
2263 else if (ipv4_is_zeronet(fl4->daddr))
2264 return ERR_PTR(-EINVAL);
2266 if (dev_out->flags & IFF_LOOPBACK)
2267 flags |= RTCF_LOCAL;
2269 if (type == RTN_BROADCAST) {
2270 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2272 } else if (type == RTN_MULTICAST) {
2273 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2274 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2276 flags &= ~RTCF_LOCAL;
2277 /* If multicast route do not exist use
2278 * default one, but do not gateway in this case.
2281 if (fi && res->prefixlen < 4)
2285 rth = rt_dst_alloc(dev_out,
2286 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2287 IN_DEV_CONF_GET(in_dev, NOXFRM));
2289 return ERR_PTR(-ENOBUFS);
2291 rth->dst.output = ip_output;
2293 rth->rt_key_dst = orig_daddr;
2294 rth->rt_key_src = orig_saddr;
2295 rth->rt_genid = rt_genid(dev_net(dev_out));
2296 rth->rt_flags = flags;
2297 rth->rt_type = type;
2298 rth->rt_key_tos = orig_rtos;
2299 rth->rt_dst = fl4->daddr;
2300 rth->rt_src = fl4->saddr;
2301 rth->rt_route_iif = 0;
2302 rth->rt_iif = orig_oif ? : dev_out->ifindex;
2303 rth->rt_oif = orig_oif;
2304 rth->rt_mark = fl4->flowi4_mark;
2306 rth->rt_gateway = fl4->daddr;
2309 RT_CACHE_STAT_INC(out_slow_tot);
2311 if (flags & RTCF_LOCAL)
2312 rth->dst.input = ip_local_deliver;
2313 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2314 if (flags & RTCF_LOCAL &&
2315 !(dev_out->flags & IFF_LOOPBACK)) {
2316 rth->dst.output = ip_mc_output;
2317 RT_CACHE_STAT_INC(out_slow_mc);
2319 #ifdef CONFIG_IP_MROUTE
2320 if (type == RTN_MULTICAST) {
2321 if (IN_DEV_MFORWARD(in_dev) &&
2322 !ipv4_is_local_multicast(fl4->daddr)) {
2323 rth->dst.input = ip_mr_input;
2324 rth->dst.output = ip_mc_output;
2330 rt_set_nexthop(rth, fl4, res, fi, type, 0);
2332 if (fl4->flowi4_flags & FLOWI_FLAG_RT_NOCACHE)
2333 rth->dst.flags |= DST_NOCACHE;
2339 * Major route resolver routine.
2340 * called with rcu_read_lock();
2343 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4)
2345 struct net_device *dev_out = NULL;
2346 __u8 tos = RT_FL_TOS(fl4);
2347 unsigned int flags = 0;
2348 struct fib_result res;
2356 #ifdef CONFIG_IP_MULTIPLE_TABLES
2360 orig_daddr = fl4->daddr;
2361 orig_saddr = fl4->saddr;
2362 orig_oif = fl4->flowi4_oif;
2364 fl4->flowi4_iif = net->loopback_dev->ifindex;
2365 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2366 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2367 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2371 rth = ERR_PTR(-EINVAL);
2372 if (ipv4_is_multicast(fl4->saddr) ||
2373 ipv4_is_lbcast(fl4->saddr) ||
2374 ipv4_is_zeronet(fl4->saddr))
2377 /* I removed check for oif == dev_out->oif here.
2378 It was wrong for two reasons:
2379 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2380 is assigned to multiple interfaces.
2381 2. Moreover, we are allowed to send packets with saddr
2382 of another iface. --ANK
2385 if (fl4->flowi4_oif == 0 &&
2386 (ipv4_is_multicast(fl4->daddr) ||
2387 ipv4_is_lbcast(fl4->daddr))) {
2388 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2389 dev_out = __ip_dev_find(net, fl4->saddr, false);
2390 if (dev_out == NULL)
2393 /* Special hack: user can direct multicasts
2394 and limited broadcast via necessary interface
2395 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2396 This hack is not just for fun, it allows
2397 vic,vat and friends to work.
2398 They bind socket to loopback, set ttl to zero
2399 and expect that it will work.
2400 From the viewpoint of routing cache they are broken,
2401 because we are not allowed to build multicast path
2402 with loopback source addr (look, routing cache
2403 cannot know, that ttl is zero, so that packet
2404 will not leave this host and route is valid).
2405 Luckily, this hack is good workaround.
2408 fl4->flowi4_oif = dev_out->ifindex;
2412 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2413 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2414 if (!__ip_dev_find(net, fl4->saddr, false))
2420 if (fl4->flowi4_oif) {
2421 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2422 rth = ERR_PTR(-ENODEV);
2423 if (dev_out == NULL)
2426 /* RACE: Check return value of inet_select_addr instead. */
2427 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2428 rth = ERR_PTR(-ENETUNREACH);
2431 if (ipv4_is_local_multicast(fl4->daddr) ||
2432 ipv4_is_lbcast(fl4->daddr)) {
2434 fl4->saddr = inet_select_addr(dev_out, 0,
2439 if (ipv4_is_multicast(fl4->daddr))
2440 fl4->saddr = inet_select_addr(dev_out, 0,
2442 else if (!fl4->daddr)
2443 fl4->saddr = inet_select_addr(dev_out, 0,
2449 fl4->daddr = fl4->saddr;
2451 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2452 dev_out = net->loopback_dev;
2453 fl4->flowi4_oif = net->loopback_dev->ifindex;
2454 res.type = RTN_LOCAL;
2455 flags |= RTCF_LOCAL;
2459 if (fib_lookup(net, fl4, &res)) {
2462 if (fl4->flowi4_oif) {
2463 /* Apparently, routing tables are wrong. Assume,
2464 that the destination is on link.
2467 Because we are allowed to send to iface
2468 even if it has NO routes and NO assigned
2469 addresses. When oif is specified, routing
2470 tables are looked up with only one purpose:
2471 to catch if destination is gatewayed, rather than
2472 direct. Moreover, if MSG_DONTROUTE is set,
2473 we send packet, ignoring both routing tables
2474 and ifaddr state. --ANK
2477 We could make it even if oif is unknown,
2478 likely IPv6, but we do not.
2481 if (fl4->saddr == 0)
2482 fl4->saddr = inet_select_addr(dev_out, 0,
2484 res.type = RTN_UNICAST;
2487 rth = ERR_PTR(-ENETUNREACH);
2491 if (res.type == RTN_LOCAL) {
2493 if (res.fi->fib_prefsrc)
2494 fl4->saddr = res.fi->fib_prefsrc;
2496 fl4->saddr = fl4->daddr;
2498 dev_out = net->loopback_dev;
2499 fl4->flowi4_oif = dev_out->ifindex;
2501 flags |= RTCF_LOCAL;
2505 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2506 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2507 fib_select_multipath(&res);
2510 if (!res.prefixlen &&
2511 res.table->tb_num_default > 1 &&
2512 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2513 fib_select_default(&res);
2516 fl4->saddr = FIB_RES_PREFSRC(net, res);
2518 dev_out = FIB_RES_DEV(res);
2519 fl4->flowi4_oif = dev_out->ifindex;
2523 rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif,
2524 tos, dev_out, flags);
2528 hash = rt_hash(orig_daddr, orig_saddr, orig_oif,
2529 rt_genid(dev_net(dev_out)));
2530 rth = rt_intern_hash(hash, rth, NULL, orig_oif);
2538 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
2543 if (!rt_caching(net))
2546 hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2549 for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2550 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2551 if (rth->rt_key_dst == flp4->daddr &&
2552 rth->rt_key_src == flp4->saddr &&
2553 rt_is_output_route(rth) &&
2554 rth->rt_oif == flp4->flowi4_oif &&
2555 rth->rt_mark == flp4->flowi4_mark &&
2556 !((rth->rt_key_tos ^ flp4->flowi4_tos) &
2557 (IPTOS_RT_MASK | RTO_ONLINK)) &&
2558 net_eq(dev_net(rth->dst.dev), net) &&
2559 !rt_is_expired(rth)) {
2560 dst_use(&rth->dst, jiffies);
2561 RT_CACHE_STAT_INC(out_hit);
2562 rcu_read_unlock_bh();
2564 flp4->saddr = rth->rt_src;
2566 flp4->daddr = rth->rt_dst;
2569 RT_CACHE_STAT_INC(out_hlist_search);
2571 rcu_read_unlock_bh();
2574 return ip_route_output_slow(net, flp4);
2576 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2578 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2583 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2585 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2587 return mtu ? : dst->dev->mtu;
2590 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2594 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sk_buff *skb)
2598 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2604 static struct dst_ops ipv4_dst_blackhole_ops = {
2606 .protocol = cpu_to_be16(ETH_P_IP),
2607 .destroy = ipv4_dst_destroy,
2608 .check = ipv4_blackhole_dst_check,
2609 .mtu = ipv4_blackhole_mtu,
2610 .default_advmss = ipv4_default_advmss,
2611 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2612 .redirect = ipv4_rt_blackhole_redirect,
2613 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2614 .neigh_lookup = ipv4_neigh_lookup,
2617 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2619 struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
2620 struct rtable *ort = (struct rtable *) dst_orig;
2623 struct dst_entry *new = &rt->dst;
2626 new->input = dst_discard;
2627 new->output = dst_discard;
2629 new->dev = ort->dst.dev;
2633 rt->rt_key_dst = ort->rt_key_dst;
2634 rt->rt_key_src = ort->rt_key_src;
2635 rt->rt_key_tos = ort->rt_key_tos;
2636 rt->rt_route_iif = ort->rt_route_iif;
2637 rt->rt_iif = ort->rt_iif;
2638 rt->rt_oif = ort->rt_oif;
2639 rt->rt_mark = ort->rt_mark;
2640 rt->rt_pmtu = ort->rt_pmtu;
2642 rt->rt_genid = rt_genid(net);
2643 rt->rt_flags = ort->rt_flags;
2644 rt->rt_type = ort->rt_type;
2645 rt->rt_dst = ort->rt_dst;
2646 rt->rt_src = ort->rt_src;
2647 rt->rt_gateway = ort->rt_gateway;
2650 atomic_inc(&rt->fi->fib_clntref);
2655 dst_release(dst_orig);
2657 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2660 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2663 struct rtable *rt = __ip_route_output_key(net, flp4);
2668 if (flp4->flowi4_proto)
2669 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2670 flowi4_to_flowi(flp4),
2675 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2677 static int rt_fill_info(struct net *net,
2678 struct sk_buff *skb, u32 pid, u32 seq, int event,
2679 int nowait, unsigned int flags)
2681 struct rtable *rt = skb_rtable(skb);
2683 struct nlmsghdr *nlh;
2684 unsigned long expires = 0;
2687 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2691 r = nlmsg_data(nlh);
2692 r->rtm_family = AF_INET;
2693 r->rtm_dst_len = 32;
2695 r->rtm_tos = rt->rt_key_tos;
2696 r->rtm_table = RT_TABLE_MAIN;
2697 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2698 goto nla_put_failure;
2699 r->rtm_type = rt->rt_type;
2700 r->rtm_scope = RT_SCOPE_UNIVERSE;
2701 r->rtm_protocol = RTPROT_UNSPEC;
2702 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2703 if (rt->rt_flags & RTCF_NOTIFY)
2704 r->rtm_flags |= RTM_F_NOTIFY;
2706 if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2707 goto nla_put_failure;
2708 if (rt->rt_key_src) {
2709 r->rtm_src_len = 32;
2710 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src))
2711 goto nla_put_failure;
2714 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2715 goto nla_put_failure;
2716 #ifdef CONFIG_IP_ROUTE_CLASSID
2717 if (rt->dst.tclassid &&
2718 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2719 goto nla_put_failure;
2721 if (!rt_is_input_route(rt) &&
2722 rt->rt_src != rt->rt_key_src) {
2723 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src))
2724 goto nla_put_failure;
2726 if (rt->rt_dst != rt->rt_gateway &&
2727 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2728 goto nla_put_failure;
2730 if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
2731 goto nla_put_failure;
2734 nla_put_be32(skb, RTA_MARK, rt->rt_mark))
2735 goto nla_put_failure;
2737 error = rt->dst.error;
2738 expires = rt->dst.expires;
2740 if (time_before(jiffies, expires))
2746 if (rt_is_input_route(rt)) {
2747 #ifdef CONFIG_IP_MROUTE
2748 __be32 dst = rt->rt_dst;
2750 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2751 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2752 int err = ipmr_get_route(net, skb,
2753 rt->rt_src, rt->rt_dst,
2759 goto nla_put_failure;
2761 if (err == -EMSGSIZE)
2762 goto nla_put_failure;
2768 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
2769 goto nla_put_failure;
2772 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2773 goto nla_put_failure;
2775 return nlmsg_end(skb, nlh);
2778 nlmsg_cancel(skb, nlh);
2782 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
2784 struct net *net = sock_net(in_skb->sk);
2786 struct nlattr *tb[RTA_MAX+1];
2787 struct rtable *rt = NULL;
2793 struct sk_buff *skb;
2795 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2799 rtm = nlmsg_data(nlh);
2801 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2807 /* Reserve room for dummy headers, this skb can pass
2808 through good chunk of routing engine.
2810 skb_reset_mac_header(skb);
2811 skb_reset_network_header(skb);
2813 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2814 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2815 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2817 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2818 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2819 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2820 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2823 struct net_device *dev;
2825 dev = __dev_get_by_index(net, iif);
2831 skb->protocol = htons(ETH_P_IP);
2835 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2838 rt = skb_rtable(skb);
2839 if (err == 0 && rt->dst.error)
2840 err = -rt->dst.error;
2842 struct flowi4 fl4 = {
2845 .flowi4_tos = rtm->rtm_tos,
2846 .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
2847 .flowi4_mark = mark,
2849 rt = ip_route_output_key(net, &fl4);
2859 skb_dst_set(skb, &rt->dst);
2860 if (rtm->rtm_flags & RTM_F_NOTIFY)
2861 rt->rt_flags |= RTCF_NOTIFY;
2863 err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2864 RTM_NEWROUTE, 0, 0);
2868 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2877 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
2884 net = sock_net(skb->sk);
2889 s_idx = idx = cb->args[1];
2890 for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
2891 if (!rt_hash_table[h].chain)
2894 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
2895 rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
2896 if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
2898 if (rt_is_expired(rt))
2900 skb_dst_set_noref(skb, &rt->dst);
2901 if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
2902 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2903 1, NLM_F_MULTI) <= 0) {
2905 rcu_read_unlock_bh();
2910 rcu_read_unlock_bh();
2919 void ip_rt_multicast_event(struct in_device *in_dev)
2921 rt_cache_flush(dev_net(in_dev->dev), 0);
2924 #ifdef CONFIG_SYSCTL
2925 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
2926 void __user *buffer,
2927 size_t *lenp, loff_t *ppos)
2934 memcpy(&ctl, __ctl, sizeof(ctl));
2935 ctl.data = &flush_delay;
2936 proc_dointvec(&ctl, write, buffer, lenp, ppos);
2938 net = (struct net *)__ctl->extra1;
2939 rt_cache_flush(net, flush_delay);
2946 static ctl_table ipv4_route_table[] = {
2948 .procname = "gc_thresh",
2949 .data = &ipv4_dst_ops.gc_thresh,
2950 .maxlen = sizeof(int),
2952 .proc_handler = proc_dointvec,
2955 .procname = "max_size",
2956 .data = &ip_rt_max_size,
2957 .maxlen = sizeof(int),
2959 .proc_handler = proc_dointvec,
2962 /* Deprecated. Use gc_min_interval_ms */
2964 .procname = "gc_min_interval",
2965 .data = &ip_rt_gc_min_interval,
2966 .maxlen = sizeof(int),
2968 .proc_handler = proc_dointvec_jiffies,
2971 .procname = "gc_min_interval_ms",
2972 .data = &ip_rt_gc_min_interval,
2973 .maxlen = sizeof(int),
2975 .proc_handler = proc_dointvec_ms_jiffies,
2978 .procname = "gc_timeout",
2979 .data = &ip_rt_gc_timeout,
2980 .maxlen = sizeof(int),
2982 .proc_handler = proc_dointvec_jiffies,
2985 .procname = "gc_interval",
2986 .data = &ip_rt_gc_interval,
2987 .maxlen = sizeof(int),
2989 .proc_handler = proc_dointvec_jiffies,
2992 .procname = "redirect_load",
2993 .data = &ip_rt_redirect_load,
2994 .maxlen = sizeof(int),
2996 .proc_handler = proc_dointvec,
2999 .procname = "redirect_number",
3000 .data = &ip_rt_redirect_number,
3001 .maxlen = sizeof(int),
3003 .proc_handler = proc_dointvec,
3006 .procname = "redirect_silence",
3007 .data = &ip_rt_redirect_silence,
3008 .maxlen = sizeof(int),
3010 .proc_handler = proc_dointvec,
3013 .procname = "error_cost",
3014 .data = &ip_rt_error_cost,
3015 .maxlen = sizeof(int),
3017 .proc_handler = proc_dointvec,
3020 .procname = "error_burst",
3021 .data = &ip_rt_error_burst,
3022 .maxlen = sizeof(int),
3024 .proc_handler = proc_dointvec,
3027 .procname = "gc_elasticity",
3028 .data = &ip_rt_gc_elasticity,
3029 .maxlen = sizeof(int),
3031 .proc_handler = proc_dointvec,
3034 .procname = "mtu_expires",
3035 .data = &ip_rt_mtu_expires,
3036 .maxlen = sizeof(int),
3038 .proc_handler = proc_dointvec_jiffies,
3041 .procname = "min_pmtu",
3042 .data = &ip_rt_min_pmtu,
3043 .maxlen = sizeof(int),
3045 .proc_handler = proc_dointvec,
3048 .procname = "min_adv_mss",
3049 .data = &ip_rt_min_advmss,
3050 .maxlen = sizeof(int),
3052 .proc_handler = proc_dointvec,
3057 static struct ctl_table ipv4_route_flush_table[] = {
3059 .procname = "flush",
3060 .maxlen = sizeof(int),
3062 .proc_handler = ipv4_sysctl_rtcache_flush,
3067 static __net_init int sysctl_route_net_init(struct net *net)
3069 struct ctl_table *tbl;
3071 tbl = ipv4_route_flush_table;
3072 if (!net_eq(net, &init_net)) {
3073 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3077 tbl[0].extra1 = net;
3079 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3080 if (net->ipv4.route_hdr == NULL)
3085 if (tbl != ipv4_route_flush_table)
3091 static __net_exit void sysctl_route_net_exit(struct net *net)
3093 struct ctl_table *tbl;
3095 tbl = net->ipv4.route_hdr->ctl_table_arg;
3096 unregister_net_sysctl_table(net->ipv4.route_hdr);
3097 BUG_ON(tbl == ipv4_route_flush_table);
3101 static __net_initdata struct pernet_operations sysctl_route_ops = {
3102 .init = sysctl_route_net_init,
3103 .exit = sysctl_route_net_exit,
3107 static __net_init int rt_genid_init(struct net *net)
3109 get_random_bytes(&net->ipv4.rt_genid,
3110 sizeof(net->ipv4.rt_genid));
3111 get_random_bytes(&net->ipv4.dev_addr_genid,
3112 sizeof(net->ipv4.dev_addr_genid));
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 static __initdata unsigned long rhash_entries;
3150 static int __init set_rhash_entries(char *str)
3157 ret = kstrtoul(str, 0, &rhash_entries);
3163 __setup("rhash_entries=", set_rhash_entries);
3165 int __init ip_rt_init(void)
3169 #ifdef CONFIG_IP_ROUTE_CLASSID
3170 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3172 panic("IP: failed to allocate ip_rt_acct\n");
3175 ipv4_dst_ops.kmem_cachep =
3176 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3177 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3179 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3181 if (dst_entries_init(&ipv4_dst_ops) < 0)
3182 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3184 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3185 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3187 rt_hash_table = (struct rt_hash_bucket *)
3188 alloc_large_system_hash("IP route cache",
3189 sizeof(struct rt_hash_bucket),
3191 (totalram_pages >= 128 * 1024) ?
3197 rhash_entries ? 0 : 512 * 1024);
3198 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3199 rt_hash_lock_init();
3201 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3202 ip_rt_max_size = (rt_hash_mask + 1) * 16;
3207 INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3208 expires_ljiffies = jiffies;
3209 schedule_delayed_work(&expires_work,
3210 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3212 if (ip_rt_proc_init())
3213 pr_err("Unable to create route proc files\n");
3216 xfrm4_init(ip_rt_max_size);
3218 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3220 #ifdef CONFIG_SYSCTL
3221 register_pernet_subsys(&sysctl_route_ops);
3223 register_pernet_subsys(&rt_genid_ops);
3224 register_pernet_subsys(&ipv4_inetpeer_ops);
3228 #ifdef CONFIG_SYSCTL
3230 * We really need to sanitize the damn ipv4 init order, then all
3231 * this nonsense will go away.
3233 void __init ip_static_sysctl_init(void)
3235 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);