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 (rth->peer && rth->peer->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_tree(net, 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 net *net = dev_net(rt->dst.dev);
1329 struct inet_peer *peer;
1331 peer = inet_getpeer_v4(net, daddr, create);
1333 if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
1336 rt->rt_peer_genid = rt_peer_genid();
1340 * Peer allocation may fail only in serious out-of-memory conditions. However
1341 * we still can generate some output.
1342 * Random ID selection looks a bit dangerous because we have no chances to
1343 * select ID being unique in a reasonable period of time.
1344 * But broken packet identifier may be better than no packet at all.
1346 static void ip_select_fb_ident(struct iphdr *iph)
1348 static DEFINE_SPINLOCK(ip_fb_id_lock);
1349 static u32 ip_fallback_id;
1352 spin_lock_bh(&ip_fb_id_lock);
1353 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1354 iph->id = htons(salt & 0xFFFF);
1355 ip_fallback_id = salt;
1356 spin_unlock_bh(&ip_fb_id_lock);
1359 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1361 struct rtable *rt = (struct rtable *) dst;
1363 if (rt && !(rt->dst.flags & DST_NOPEER)) {
1364 struct inet_peer *peer = rt_get_peer_create(rt, rt->rt_dst);
1366 /* If peer is attached to destination, it is never detached,
1367 so that we need not to grab a lock to dereference it.
1370 iph->id = htons(inet_getid(peer, more));
1374 pr_debug("rt_bind_peer(0) @%p\n", __builtin_return_address(0));
1376 ip_select_fb_ident(iph);
1378 EXPORT_SYMBOL(__ip_select_ident);
1380 static void rt_del(unsigned int hash, struct rtable *rt)
1382 struct rtable __rcu **rthp;
1385 rthp = &rt_hash_table[hash].chain;
1386 spin_lock_bh(rt_hash_lock_addr(hash));
1388 while ((aux = rcu_dereference_protected(*rthp,
1389 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1390 if (aux == rt || rt_is_expired(aux)) {
1391 *rthp = aux->dst.rt_next;
1395 rthp = &aux->dst.rt_next;
1397 spin_unlock_bh(rt_hash_lock_addr(hash));
1400 static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
1402 struct rtable *rt = (struct rtable *) dst;
1403 __be32 orig_gw = rt->rt_gateway;
1404 struct neighbour *n, *old_n;
1406 dst_confirm(&rt->dst);
1408 rt->rt_gateway = peer->redirect_learned.a4;
1410 n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1412 rt->rt_gateway = orig_gw;
1415 old_n = xchg(&rt->dst._neighbour, n);
1417 neigh_release(old_n);
1418 if (!(n->nud_state & NUD_VALID)) {
1419 neigh_event_send(n, NULL);
1421 rt->rt_flags |= RTCF_REDIRECTED;
1422 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
1426 /* called in rcu_read_lock() section */
1427 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1428 __be32 saddr, struct net_device *dev)
1431 struct in_device *in_dev = __in_dev_get_rcu(dev);
1432 __be32 skeys[2] = { saddr, 0 };
1433 int ikeys[2] = { dev->ifindex, 0 };
1434 struct inet_peer *peer;
1441 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1442 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1443 ipv4_is_zeronet(new_gw))
1444 goto reject_redirect;
1446 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1447 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1448 goto reject_redirect;
1449 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1450 goto reject_redirect;
1452 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1453 goto reject_redirect;
1456 for (s = 0; s < 2; s++) {
1457 for (i = 0; i < 2; i++) {
1459 struct rtable __rcu **rthp;
1462 hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net));
1464 rthp = &rt_hash_table[hash].chain;
1466 while ((rt = rcu_dereference(*rthp)) != NULL) {
1467 rthp = &rt->dst.rt_next;
1469 if (rt->rt_key_dst != daddr ||
1470 rt->rt_key_src != skeys[s] ||
1471 rt->rt_oif != ikeys[i] ||
1472 rt_is_input_route(rt) ||
1473 rt_is_expired(rt) ||
1474 !net_eq(dev_net(rt->dst.dev), net) ||
1476 rt->dst.dev != dev ||
1477 rt->rt_gateway != old_gw)
1480 peer = rt_get_peer_create(rt, rt->rt_dst);
1482 if (peer->redirect_learned.a4 != new_gw) {
1483 peer->redirect_learned.a4 = new_gw;
1484 atomic_inc(&__rt_peer_genid);
1486 check_peer_redir(&rt->dst, peer);
1494 #ifdef CONFIG_IP_ROUTE_VERBOSE
1495 if (IN_DEV_LOG_MARTIANS(in_dev))
1496 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
1497 " Advised path = %pI4 -> %pI4\n",
1498 &old_gw, dev->name, &new_gw,
1504 static bool peer_pmtu_expired(struct inet_peer *peer)
1506 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1509 time_after_eq(jiffies, orig) &&
1510 cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1513 static bool peer_pmtu_cleaned(struct inet_peer *peer)
1515 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1518 cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1521 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1523 struct rtable *rt = (struct rtable *)dst;
1524 struct dst_entry *ret = dst;
1527 if (dst->obsolete > 0) {
1530 } else if (rt->rt_flags & RTCF_REDIRECTED) {
1531 unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1533 rt_genid(dev_net(dst->dev)));
1536 } else if (rt->peer && peer_pmtu_expired(rt->peer)) {
1537 dst_metric_set(dst, RTAX_MTU, rt->peer->pmtu_orig);
1545 * 1. The first ip_rt_redirect_number redirects are sent
1546 * with exponential backoff, then we stop sending them at all,
1547 * assuming that the host ignores our redirects.
1548 * 2. If we did not see packets requiring redirects
1549 * during ip_rt_redirect_silence, we assume that the host
1550 * forgot redirected route and start to send redirects again.
1552 * This algorithm is much cheaper and more intelligent than dumb load limiting
1555 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1556 * and "frag. need" (breaks PMTU discovery) in icmp.c.
1559 void ip_rt_send_redirect(struct sk_buff *skb)
1561 struct rtable *rt = skb_rtable(skb);
1562 struct in_device *in_dev;
1563 struct inet_peer *peer;
1567 in_dev = __in_dev_get_rcu(rt->dst.dev);
1568 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1572 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1575 peer = rt_get_peer_create(rt, rt->rt_dst);
1577 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1581 /* No redirected packets during ip_rt_redirect_silence;
1582 * reset the algorithm.
1584 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1585 peer->rate_tokens = 0;
1587 /* Too many ignored redirects; do not send anything
1588 * set dst.rate_last to the last seen redirected packet.
1590 if (peer->rate_tokens >= ip_rt_redirect_number) {
1591 peer->rate_last = jiffies;
1595 /* Check for load limit; set rate_last to the latest sent
1598 if (peer->rate_tokens == 0 ||
1601 (ip_rt_redirect_load << peer->rate_tokens)))) {
1602 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1603 peer->rate_last = jiffies;
1604 ++peer->rate_tokens;
1605 #ifdef CONFIG_IP_ROUTE_VERBOSE
1607 peer->rate_tokens == ip_rt_redirect_number)
1608 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
1609 &ip_hdr(skb)->saddr, rt->rt_iif,
1610 &rt->rt_dst, &rt->rt_gateway);
1615 static int ip_error(struct sk_buff *skb)
1617 struct rtable *rt = skb_rtable(skb);
1618 struct inet_peer *peer;
1623 switch (rt->dst.error) {
1628 code = ICMP_HOST_UNREACH;
1631 code = ICMP_NET_UNREACH;
1632 IP_INC_STATS_BH(dev_net(rt->dst.dev),
1633 IPSTATS_MIB_INNOROUTES);
1636 code = ICMP_PKT_FILTERED;
1640 peer = rt_get_peer_create(rt, rt->rt_dst);
1645 peer->rate_tokens += now - peer->rate_last;
1646 if (peer->rate_tokens > ip_rt_error_burst)
1647 peer->rate_tokens = ip_rt_error_burst;
1648 peer->rate_last = now;
1649 if (peer->rate_tokens >= ip_rt_error_cost)
1650 peer->rate_tokens -= ip_rt_error_cost;
1655 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1657 out: kfree_skb(skb);
1662 * The last two values are not from the RFC but
1663 * are needed for AMPRnet AX.25 paths.
1666 static const unsigned short mtu_plateau[] =
1667 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1669 static inline unsigned short guess_mtu(unsigned short old_mtu)
1673 for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1674 if (old_mtu > mtu_plateau[i])
1675 return mtu_plateau[i];
1679 unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
1680 unsigned short new_mtu,
1681 struct net_device *dev)
1683 unsigned short old_mtu = ntohs(iph->tot_len);
1684 unsigned short est_mtu = 0;
1685 struct inet_peer *peer;
1687 peer = inet_getpeer_v4(net, iph->daddr, 1);
1689 unsigned short mtu = new_mtu;
1691 if (new_mtu < 68 || new_mtu >= old_mtu) {
1692 /* BSD 4.2 derived systems incorrectly adjust
1693 * tot_len by the IP header length, and report
1694 * a zero MTU in the ICMP message.
1697 old_mtu >= 68 + (iph->ihl << 2))
1698 old_mtu -= iph->ihl << 2;
1699 mtu = guess_mtu(old_mtu);
1702 if (mtu < ip_rt_min_pmtu)
1703 mtu = ip_rt_min_pmtu;
1704 if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
1705 unsigned long pmtu_expires;
1707 pmtu_expires = jiffies + ip_rt_mtu_expires;
1712 peer->pmtu_learned = mtu;
1713 peer->pmtu_expires = pmtu_expires;
1714 atomic_inc(&__rt_peer_genid);
1719 return est_mtu ? : new_mtu;
1722 static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
1724 unsigned long expires = ACCESS_ONCE(peer->pmtu_expires);
1728 if (time_before(jiffies, expires)) {
1729 u32 orig_dst_mtu = dst_mtu(dst);
1730 if (peer->pmtu_learned < orig_dst_mtu) {
1731 if (!peer->pmtu_orig)
1732 peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU);
1733 dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned);
1735 } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires)
1736 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1739 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1741 struct rtable *rt = (struct rtable *) dst;
1742 struct inet_peer *peer;
1746 peer = rt_get_peer_create(rt, rt->rt_dst);
1748 unsigned long pmtu_expires = ACCESS_ONCE(peer->pmtu_expires);
1750 if (mtu < ip_rt_min_pmtu)
1751 mtu = ip_rt_min_pmtu;
1752 if (!pmtu_expires || mtu < peer->pmtu_learned) {
1754 pmtu_expires = jiffies + ip_rt_mtu_expires;
1758 peer->pmtu_learned = mtu;
1759 peer->pmtu_expires = pmtu_expires;
1761 atomic_inc(&__rt_peer_genid);
1762 rt->rt_peer_genid = rt_peer_genid();
1764 check_peer_pmtu(dst, peer);
1769 static void ipv4_validate_peer(struct rtable *rt)
1771 if (rt->rt_peer_genid != rt_peer_genid()) {
1772 struct inet_peer *peer = rt_get_peer(rt, rt->rt_dst);
1775 check_peer_pmtu(&rt->dst, peer);
1777 if (peer->redirect_learned.a4 &&
1778 peer->redirect_learned.a4 != rt->rt_gateway)
1779 check_peer_redir(&rt->dst, peer);
1782 rt->rt_peer_genid = rt_peer_genid();
1786 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1788 struct rtable *rt = (struct rtable *) dst;
1790 if (rt_is_expired(rt))
1792 ipv4_validate_peer(rt);
1796 static void ipv4_dst_destroy(struct dst_entry *dst)
1798 struct rtable *rt = (struct rtable *) dst;
1799 struct inet_peer *peer = rt->peer;
1802 fib_info_put(rt->fi);
1812 static void ipv4_link_failure(struct sk_buff *skb)
1816 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1818 rt = skb_rtable(skb);
1819 if (rt && rt->peer && peer_pmtu_cleaned(rt->peer))
1820 dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig);
1823 static int ip_rt_bug(struct sk_buff *skb)
1825 pr_debug("%s: %pI4 -> %pI4, %s\n",
1826 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1827 skb->dev ? skb->dev->name : "?");
1834 We do not cache source address of outgoing interface,
1835 because it is used only by IP RR, TS and SRR options,
1836 so that it out of fast path.
1838 BTW remember: "addr" is allowed to be not aligned
1842 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1846 if (rt_is_output_route(rt))
1847 src = ip_hdr(skb)->saddr;
1849 struct fib_result res;
1855 memset(&fl4, 0, sizeof(fl4));
1856 fl4.daddr = iph->daddr;
1857 fl4.saddr = iph->saddr;
1858 fl4.flowi4_tos = RT_TOS(iph->tos);
1859 fl4.flowi4_oif = rt->dst.dev->ifindex;
1860 fl4.flowi4_iif = skb->dev->ifindex;
1861 fl4.flowi4_mark = skb->mark;
1864 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1865 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1867 src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1871 memcpy(addr, &src, 4);
1874 #ifdef CONFIG_IP_ROUTE_CLASSID
1875 static void set_class_tag(struct rtable *rt, u32 tag)
1877 if (!(rt->dst.tclassid & 0xFFFF))
1878 rt->dst.tclassid |= tag & 0xFFFF;
1879 if (!(rt->dst.tclassid & 0xFFFF0000))
1880 rt->dst.tclassid |= tag & 0xFFFF0000;
1884 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1886 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1889 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1891 if (advmss > 65535 - 40)
1892 advmss = 65535 - 40;
1897 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1899 const struct rtable *rt = (const struct rtable *) dst;
1900 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1902 if (mtu && rt_is_output_route(rt))
1905 mtu = dst->dev->mtu;
1907 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1909 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1913 if (mtu > IP_MAX_MTU)
1919 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1920 struct fib_info *fi)
1922 struct net *net = dev_net(rt->dst.dev);
1923 struct inet_peer *peer;
1926 /* If a peer entry exists for this destination, we must hook
1927 * it up in order to get at cached metrics.
1929 if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
1932 rt->peer = peer = inet_getpeer_v4(net, rt->rt_dst, create);
1934 rt->rt_peer_genid = rt_peer_genid();
1935 if (inet_metrics_new(peer))
1936 memcpy(peer->metrics, fi->fib_metrics,
1937 sizeof(u32) * RTAX_MAX);
1938 dst_init_metrics(&rt->dst, peer->metrics, false);
1940 check_peer_pmtu(&rt->dst, peer);
1942 if (peer->redirect_learned.a4 &&
1943 peer->redirect_learned.a4 != rt->rt_gateway) {
1944 rt->rt_gateway = peer->redirect_learned.a4;
1945 rt->rt_flags |= RTCF_REDIRECTED;
1948 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1950 atomic_inc(&fi->fib_clntref);
1952 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1956 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1957 const struct fib_result *res,
1958 struct fib_info *fi, u16 type, u32 itag)
1960 struct dst_entry *dst = &rt->dst;
1963 if (FIB_RES_GW(*res) &&
1964 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1965 rt->rt_gateway = FIB_RES_GW(*res);
1966 rt_init_metrics(rt, fl4, fi);
1967 #ifdef CONFIG_IP_ROUTE_CLASSID
1968 dst->tclassid = FIB_RES_NH(*res).nh_tclassid;
1972 if (dst_mtu(dst) > IP_MAX_MTU)
1973 dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);
1974 if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40)
1975 dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40);
1977 #ifdef CONFIG_IP_ROUTE_CLASSID
1978 #ifdef CONFIG_IP_MULTIPLE_TABLES
1979 set_class_tag(rt, fib_rules_tclass(res));
1981 set_class_tag(rt, itag);
1985 static struct rtable *rt_dst_alloc(struct net_device *dev,
1986 bool nopolicy, bool noxfrm)
1988 return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
1990 (nopolicy ? DST_NOPOLICY : 0) |
1991 (noxfrm ? DST_NOXFRM : 0));
1994 /* called in rcu_read_lock() section */
1995 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1996 u8 tos, struct net_device *dev, int our)
2001 struct in_device *in_dev = __in_dev_get_rcu(dev);
2005 /* Primary sanity checks. */
2010 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
2011 ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
2014 if (ipv4_is_zeronet(saddr)) {
2015 if (!ipv4_is_local_multicast(daddr))
2017 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2019 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst,
2024 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
2025 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2029 #ifdef CONFIG_IP_ROUTE_CLASSID
2030 rth->dst.tclassid = itag;
2032 rth->dst.output = ip_rt_bug;
2034 rth->rt_key_dst = daddr;
2035 rth->rt_key_src = saddr;
2036 rth->rt_genid = rt_genid(dev_net(dev));
2037 rth->rt_flags = RTCF_MULTICAST;
2038 rth->rt_type = RTN_MULTICAST;
2039 rth->rt_key_tos = tos;
2040 rth->rt_dst = daddr;
2041 rth->rt_src = saddr;
2042 rth->rt_route_iif = dev->ifindex;
2043 rth->rt_iif = dev->ifindex;
2045 rth->rt_mark = skb->mark;
2046 rth->rt_gateway = daddr;
2047 rth->rt_spec_dst= spec_dst;
2048 rth->rt_peer_genid = 0;
2052 rth->dst.input= ip_local_deliver;
2053 rth->rt_flags |= RTCF_LOCAL;
2056 #ifdef CONFIG_IP_MROUTE
2057 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
2058 rth->dst.input = ip_mr_input;
2060 RT_CACHE_STAT_INC(in_slow_mc);
2062 hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
2063 rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
2064 return IS_ERR(rth) ? PTR_ERR(rth) : 0;
2075 static void ip_handle_martian_source(struct net_device *dev,
2076 struct in_device *in_dev,
2077 struct sk_buff *skb,
2081 RT_CACHE_STAT_INC(in_martian_src);
2082 #ifdef CONFIG_IP_ROUTE_VERBOSE
2083 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
2085 * RFC1812 recommendation, if source is martian,
2086 * the only hint is MAC header.
2088 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
2089 &daddr, &saddr, dev->name);
2090 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
2091 print_hex_dump(KERN_WARNING, "ll header: ",
2092 DUMP_PREFIX_OFFSET, 16, 1,
2093 skb_mac_header(skb),
2094 dev->hard_header_len, true);
2100 /* called in rcu_read_lock() section */
2101 static int __mkroute_input(struct sk_buff *skb,
2102 const struct fib_result *res,
2103 struct in_device *in_dev,
2104 __be32 daddr, __be32 saddr, u32 tos,
2105 struct rtable **result)
2109 struct in_device *out_dev;
2110 unsigned int flags = 0;
2114 /* get a working reference to the output device */
2115 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
2116 if (out_dev == NULL) {
2117 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
2122 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
2123 in_dev->dev, &spec_dst, &itag);
2125 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
2132 flags |= RTCF_DIRECTSRC;
2134 if (out_dev == in_dev && err &&
2135 (IN_DEV_SHARED_MEDIA(out_dev) ||
2136 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
2137 flags |= RTCF_DOREDIRECT;
2139 if (skb->protocol != htons(ETH_P_IP)) {
2140 /* Not IP (i.e. ARP). Do not create route, if it is
2141 * invalid for proxy arp. DNAT routes are always valid.
2143 * Proxy arp feature have been extended to allow, ARP
2144 * replies back to the same interface, to support
2145 * Private VLAN switch technologies. See arp.c.
2147 if (out_dev == in_dev &&
2148 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2154 rth = rt_dst_alloc(out_dev->dev,
2155 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2156 IN_DEV_CONF_GET(out_dev, NOXFRM));
2162 rth->rt_key_dst = daddr;
2163 rth->rt_key_src = saddr;
2164 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
2165 rth->rt_flags = flags;
2166 rth->rt_type = res->type;
2167 rth->rt_key_tos = tos;
2168 rth->rt_dst = daddr;
2169 rth->rt_src = saddr;
2170 rth->rt_route_iif = in_dev->dev->ifindex;
2171 rth->rt_iif = in_dev->dev->ifindex;
2173 rth->rt_mark = skb->mark;
2174 rth->rt_gateway = daddr;
2175 rth->rt_spec_dst= spec_dst;
2176 rth->rt_peer_genid = 0;
2180 rth->dst.input = ip_forward;
2181 rth->dst.output = ip_output;
2183 rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
2191 static int ip_mkroute_input(struct sk_buff *skb,
2192 struct fib_result *res,
2193 const struct flowi4 *fl4,
2194 struct in_device *in_dev,
2195 __be32 daddr, __be32 saddr, u32 tos)
2197 struct rtable *rth = NULL;
2201 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2202 if (res->fi && res->fi->fib_nhs > 1)
2203 fib_select_multipath(res);
2206 /* create a routing cache entry */
2207 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
2211 /* put it into the cache */
2212 hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
2213 rt_genid(dev_net(rth->dst.dev)));
2214 rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
2216 return PTR_ERR(rth);
2221 * NOTE. We drop all the packets that has local source
2222 * addresses, because every properly looped back packet
2223 * must have correct destination already attached by output routine.
2225 * Such approach solves two big problems:
2226 * 1. Not simplex devices are handled properly.
2227 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2228 * called with rcu_read_lock()
2231 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2232 u8 tos, struct net_device *dev)
2234 struct fib_result res;
2235 struct in_device *in_dev = __in_dev_get_rcu(dev);
2237 unsigned int flags = 0;
2243 struct net *net = dev_net(dev);
2245 /* IP on this device is disabled. */
2250 /* Check for the most weird martians, which can be not detected
2254 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
2255 ipv4_is_loopback(saddr))
2256 goto martian_source;
2258 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2261 /* Accept zero addresses only to limited broadcast;
2262 * I even do not know to fix it or not. Waiting for complains :-)
2264 if (ipv4_is_zeronet(saddr))
2265 goto martian_source;
2267 if (ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr))
2268 goto martian_destination;
2271 * Now we are ready to route packet.
2274 fl4.flowi4_iif = dev->ifindex;
2275 fl4.flowi4_mark = skb->mark;
2276 fl4.flowi4_tos = tos;
2277 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2280 err = fib_lookup(net, &fl4, &res);
2282 if (!IN_DEV_FORWARD(in_dev))
2287 RT_CACHE_STAT_INC(in_slow_tot);
2289 if (res.type == RTN_BROADCAST)
2292 if (res.type == RTN_LOCAL) {
2293 err = fib_validate_source(skb, saddr, daddr, tos,
2294 net->loopback_dev->ifindex,
2295 dev, &spec_dst, &itag);
2297 goto martian_source_keep_err;
2299 flags |= RTCF_DIRECTSRC;
2304 if (!IN_DEV_FORWARD(in_dev))
2306 if (res.type != RTN_UNICAST)
2307 goto martian_destination;
2309 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2313 if (skb->protocol != htons(ETH_P_IP))
2316 if (ipv4_is_zeronet(saddr))
2317 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2319 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst,
2322 goto martian_source_keep_err;
2324 flags |= RTCF_DIRECTSRC;
2326 flags |= RTCF_BROADCAST;
2327 res.type = RTN_BROADCAST;
2328 RT_CACHE_STAT_INC(in_brd);
2331 rth = rt_dst_alloc(net->loopback_dev,
2332 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2336 rth->dst.input= ip_local_deliver;
2337 rth->dst.output= ip_rt_bug;
2338 #ifdef CONFIG_IP_ROUTE_CLASSID
2339 rth->dst.tclassid = itag;
2342 rth->rt_key_dst = daddr;
2343 rth->rt_key_src = saddr;
2344 rth->rt_genid = rt_genid(net);
2345 rth->rt_flags = flags|RTCF_LOCAL;
2346 rth->rt_type = res.type;
2347 rth->rt_key_tos = tos;
2348 rth->rt_dst = daddr;
2349 rth->rt_src = saddr;
2350 #ifdef CONFIG_IP_ROUTE_CLASSID
2351 rth->dst.tclassid = itag;
2353 rth->rt_route_iif = dev->ifindex;
2354 rth->rt_iif = dev->ifindex;
2356 rth->rt_mark = skb->mark;
2357 rth->rt_gateway = daddr;
2358 rth->rt_spec_dst= spec_dst;
2359 rth->rt_peer_genid = 0;
2362 if (res.type == RTN_UNREACHABLE) {
2363 rth->dst.input= ip_error;
2364 rth->dst.error= -err;
2365 rth->rt_flags &= ~RTCF_LOCAL;
2367 hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2368 rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2375 RT_CACHE_STAT_INC(in_no_route);
2376 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2377 res.type = RTN_UNREACHABLE;
2383 * Do not cache martian addresses: they should be logged (RFC1812)
2385 martian_destination:
2386 RT_CACHE_STAT_INC(in_martian_dst);
2387 #ifdef CONFIG_IP_ROUTE_VERBOSE
2388 if (IN_DEV_LOG_MARTIANS(in_dev))
2389 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2390 &daddr, &saddr, dev->name);
2394 err = -EHOSTUNREACH;
2407 martian_source_keep_err:
2408 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2412 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2413 u8 tos, struct net_device *dev, bool noref)
2417 int iif = dev->ifindex;
2425 if (!rt_caching(net))
2428 tos &= IPTOS_RT_MASK;
2429 hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2431 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2432 rth = rcu_dereference(rth->dst.rt_next)) {
2433 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2434 ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2435 (rth->rt_route_iif ^ iif) |
2436 (rth->rt_key_tos ^ tos)) == 0 &&
2437 rth->rt_mark == skb->mark &&
2438 net_eq(dev_net(rth->dst.dev), net) &&
2439 !rt_is_expired(rth)) {
2440 ipv4_validate_peer(rth);
2442 dst_use_noref(&rth->dst, jiffies);
2443 skb_dst_set_noref(skb, &rth->dst);
2445 dst_use(&rth->dst, jiffies);
2446 skb_dst_set(skb, &rth->dst);
2448 RT_CACHE_STAT_INC(in_hit);
2452 RT_CACHE_STAT_INC(in_hlist_search);
2456 /* Multicast recognition logic is moved from route cache to here.
2457 The problem was that too many Ethernet cards have broken/missing
2458 hardware multicast filters :-( As result the host on multicasting
2459 network acquires a lot of useless route cache entries, sort of
2460 SDR messages from all the world. Now we try to get rid of them.
2461 Really, provided software IP multicast filter is organized
2462 reasonably (at least, hashed), it does not result in a slowdown
2463 comparing with route cache reject entries.
2464 Note, that multicast routers are not affected, because
2465 route cache entry is created eventually.
2467 if (ipv4_is_multicast(daddr)) {
2468 struct in_device *in_dev = __in_dev_get_rcu(dev);
2471 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2472 ip_hdr(skb)->protocol);
2474 #ifdef CONFIG_IP_MROUTE
2476 (!ipv4_is_local_multicast(daddr) &&
2477 IN_DEV_MFORWARD(in_dev))
2480 int res = ip_route_input_mc(skb, daddr, saddr,
2489 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2493 EXPORT_SYMBOL(ip_route_input_common);
2495 /* called with rcu_read_lock() */
2496 static struct rtable *__mkroute_output(const struct fib_result *res,
2497 const struct flowi4 *fl4,
2498 __be32 orig_daddr, __be32 orig_saddr,
2499 int orig_oif, __u8 orig_rtos,
2500 struct net_device *dev_out,
2503 struct fib_info *fi = res->fi;
2504 struct in_device *in_dev;
2505 u16 type = res->type;
2508 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2509 return ERR_PTR(-EINVAL);
2511 if (ipv4_is_lbcast(fl4->daddr))
2512 type = RTN_BROADCAST;
2513 else if (ipv4_is_multicast(fl4->daddr))
2514 type = RTN_MULTICAST;
2515 else if (ipv4_is_zeronet(fl4->daddr))
2516 return ERR_PTR(-EINVAL);
2518 if (dev_out->flags & IFF_LOOPBACK)
2519 flags |= RTCF_LOCAL;
2521 in_dev = __in_dev_get_rcu(dev_out);
2523 return ERR_PTR(-EINVAL);
2525 if (type == RTN_BROADCAST) {
2526 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2528 } else if (type == RTN_MULTICAST) {
2529 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2530 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2532 flags &= ~RTCF_LOCAL;
2533 /* If multicast route do not exist use
2534 * default one, but do not gateway in this case.
2537 if (fi && res->prefixlen < 4)
2541 rth = rt_dst_alloc(dev_out,
2542 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2543 IN_DEV_CONF_GET(in_dev, NOXFRM));
2545 return ERR_PTR(-ENOBUFS);
2547 rth->dst.output = ip_output;
2549 rth->rt_key_dst = orig_daddr;
2550 rth->rt_key_src = orig_saddr;
2551 rth->rt_genid = rt_genid(dev_net(dev_out));
2552 rth->rt_flags = flags;
2553 rth->rt_type = type;
2554 rth->rt_key_tos = orig_rtos;
2555 rth->rt_dst = fl4->daddr;
2556 rth->rt_src = fl4->saddr;
2557 rth->rt_route_iif = 0;
2558 rth->rt_iif = orig_oif ? : dev_out->ifindex;
2559 rth->rt_oif = orig_oif;
2560 rth->rt_mark = fl4->flowi4_mark;
2561 rth->rt_gateway = fl4->daddr;
2562 rth->rt_spec_dst= fl4->saddr;
2563 rth->rt_peer_genid = 0;
2567 RT_CACHE_STAT_INC(out_slow_tot);
2569 if (flags & RTCF_LOCAL) {
2570 rth->dst.input = ip_local_deliver;
2571 rth->rt_spec_dst = fl4->daddr;
2573 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2574 rth->rt_spec_dst = fl4->saddr;
2575 if (flags & RTCF_LOCAL &&
2576 !(dev_out->flags & IFF_LOOPBACK)) {
2577 rth->dst.output = ip_mc_output;
2578 RT_CACHE_STAT_INC(out_slow_mc);
2580 #ifdef CONFIG_IP_MROUTE
2581 if (type == RTN_MULTICAST) {
2582 if (IN_DEV_MFORWARD(in_dev) &&
2583 !ipv4_is_local_multicast(fl4->daddr)) {
2584 rth->dst.input = ip_mr_input;
2585 rth->dst.output = ip_mc_output;
2591 rt_set_nexthop(rth, fl4, res, fi, type, 0);
2597 * Major route resolver routine.
2598 * called with rcu_read_lock();
2601 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4)
2603 struct net_device *dev_out = NULL;
2604 __u8 tos = RT_FL_TOS(fl4);
2605 unsigned int flags = 0;
2606 struct fib_result res;
2613 #ifdef CONFIG_IP_MULTIPLE_TABLES
2617 orig_daddr = fl4->daddr;
2618 orig_saddr = fl4->saddr;
2619 orig_oif = fl4->flowi4_oif;
2621 fl4->flowi4_iif = net->loopback_dev->ifindex;
2622 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2623 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2624 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2628 rth = ERR_PTR(-EINVAL);
2629 if (ipv4_is_multicast(fl4->saddr) ||
2630 ipv4_is_lbcast(fl4->saddr) ||
2631 ipv4_is_zeronet(fl4->saddr))
2634 /* I removed check for oif == dev_out->oif here.
2635 It was wrong for two reasons:
2636 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2637 is assigned to multiple interfaces.
2638 2. Moreover, we are allowed to send packets with saddr
2639 of another iface. --ANK
2642 if (fl4->flowi4_oif == 0 &&
2643 (ipv4_is_multicast(fl4->daddr) ||
2644 ipv4_is_lbcast(fl4->daddr))) {
2645 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2646 dev_out = __ip_dev_find(net, fl4->saddr, false);
2647 if (dev_out == NULL)
2650 /* Special hack: user can direct multicasts
2651 and limited broadcast via necessary interface
2652 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2653 This hack is not just for fun, it allows
2654 vic,vat and friends to work.
2655 They bind socket to loopback, set ttl to zero
2656 and expect that it will work.
2657 From the viewpoint of routing cache they are broken,
2658 because we are not allowed to build multicast path
2659 with loopback source addr (look, routing cache
2660 cannot know, that ttl is zero, so that packet
2661 will not leave this host and route is valid).
2662 Luckily, this hack is good workaround.
2665 fl4->flowi4_oif = dev_out->ifindex;
2669 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2670 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2671 if (!__ip_dev_find(net, fl4->saddr, false))
2677 if (fl4->flowi4_oif) {
2678 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2679 rth = ERR_PTR(-ENODEV);
2680 if (dev_out == NULL)
2683 /* RACE: Check return value of inet_select_addr instead. */
2684 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2685 rth = ERR_PTR(-ENETUNREACH);
2688 if (ipv4_is_local_multicast(fl4->daddr) ||
2689 ipv4_is_lbcast(fl4->daddr)) {
2691 fl4->saddr = inet_select_addr(dev_out, 0,
2696 if (ipv4_is_multicast(fl4->daddr))
2697 fl4->saddr = inet_select_addr(dev_out, 0,
2699 else if (!fl4->daddr)
2700 fl4->saddr = inet_select_addr(dev_out, 0,
2706 fl4->daddr = fl4->saddr;
2708 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2709 dev_out = net->loopback_dev;
2710 fl4->flowi4_oif = net->loopback_dev->ifindex;
2711 res.type = RTN_LOCAL;
2712 flags |= RTCF_LOCAL;
2716 if (fib_lookup(net, fl4, &res)) {
2718 if (fl4->flowi4_oif) {
2719 /* Apparently, routing tables are wrong. Assume,
2720 that the destination is on link.
2723 Because we are allowed to send to iface
2724 even if it has NO routes and NO assigned
2725 addresses. When oif is specified, routing
2726 tables are looked up with only one purpose:
2727 to catch if destination is gatewayed, rather than
2728 direct. Moreover, if MSG_DONTROUTE is set,
2729 we send packet, ignoring both routing tables
2730 and ifaddr state. --ANK
2733 We could make it even if oif is unknown,
2734 likely IPv6, but we do not.
2737 if (fl4->saddr == 0)
2738 fl4->saddr = inet_select_addr(dev_out, 0,
2740 res.type = RTN_UNICAST;
2743 rth = ERR_PTR(-ENETUNREACH);
2747 if (res.type == RTN_LOCAL) {
2749 if (res.fi->fib_prefsrc)
2750 fl4->saddr = res.fi->fib_prefsrc;
2752 fl4->saddr = fl4->daddr;
2754 dev_out = net->loopback_dev;
2755 fl4->flowi4_oif = dev_out->ifindex;
2757 flags |= RTCF_LOCAL;
2761 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2762 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2763 fib_select_multipath(&res);
2766 if (!res.prefixlen &&
2767 res.table->tb_num_default > 1 &&
2768 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2769 fib_select_default(&res);
2772 fl4->saddr = FIB_RES_PREFSRC(net, res);
2774 dev_out = FIB_RES_DEV(res);
2775 fl4->flowi4_oif = dev_out->ifindex;
2779 rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif,
2780 tos, dev_out, flags);
2784 hash = rt_hash(orig_daddr, orig_saddr, orig_oif,
2785 rt_genid(dev_net(dev_out)));
2786 rth = rt_intern_hash(hash, rth, NULL, orig_oif);
2794 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
2799 if (!rt_caching(net))
2802 hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2805 for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2806 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2807 if (rth->rt_key_dst == flp4->daddr &&
2808 rth->rt_key_src == flp4->saddr &&
2809 rt_is_output_route(rth) &&
2810 rth->rt_oif == flp4->flowi4_oif &&
2811 rth->rt_mark == flp4->flowi4_mark &&
2812 !((rth->rt_key_tos ^ flp4->flowi4_tos) &
2813 (IPTOS_RT_MASK | RTO_ONLINK)) &&
2814 net_eq(dev_net(rth->dst.dev), net) &&
2815 !rt_is_expired(rth)) {
2816 ipv4_validate_peer(rth);
2817 dst_use(&rth->dst, jiffies);
2818 RT_CACHE_STAT_INC(out_hit);
2819 rcu_read_unlock_bh();
2821 flp4->saddr = rth->rt_src;
2823 flp4->daddr = rth->rt_dst;
2826 RT_CACHE_STAT_INC(out_hlist_search);
2828 rcu_read_unlock_bh();
2831 return ip_route_output_slow(net, flp4);
2833 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2835 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2840 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2842 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2844 return mtu ? : dst->dev->mtu;
2847 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2851 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2857 static struct dst_ops ipv4_dst_blackhole_ops = {
2859 .protocol = cpu_to_be16(ETH_P_IP),
2860 .destroy = ipv4_dst_destroy,
2861 .check = ipv4_blackhole_dst_check,
2862 .mtu = ipv4_blackhole_mtu,
2863 .default_advmss = ipv4_default_advmss,
2864 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2865 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2866 .neigh_lookup = ipv4_neigh_lookup,
2869 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2871 struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
2872 struct rtable *ort = (struct rtable *) dst_orig;
2875 struct dst_entry *new = &rt->dst;
2878 new->input = dst_discard;
2879 new->output = dst_discard;
2880 dst_copy_metrics(new, &ort->dst);
2882 new->dev = ort->dst.dev;
2886 rt->rt_key_dst = ort->rt_key_dst;
2887 rt->rt_key_src = ort->rt_key_src;
2888 rt->rt_key_tos = ort->rt_key_tos;
2889 rt->rt_route_iif = ort->rt_route_iif;
2890 rt->rt_iif = ort->rt_iif;
2891 rt->rt_oif = ort->rt_oif;
2892 rt->rt_mark = ort->rt_mark;
2894 rt->rt_genid = rt_genid(net);
2895 rt->rt_flags = ort->rt_flags;
2896 rt->rt_type = ort->rt_type;
2897 rt->rt_dst = ort->rt_dst;
2898 rt->rt_src = ort->rt_src;
2899 rt->rt_gateway = ort->rt_gateway;
2900 rt->rt_spec_dst = ort->rt_spec_dst;
2901 rt->peer = ort->peer;
2903 atomic_inc(&rt->peer->refcnt);
2906 atomic_inc(&rt->fi->fib_clntref);
2911 dst_release(dst_orig);
2913 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2916 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2919 struct rtable *rt = __ip_route_output_key(net, flp4);
2924 if (flp4->flowi4_proto)
2925 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2926 flowi4_to_flowi(flp4),
2931 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2933 static int rt_fill_info(struct net *net,
2934 struct sk_buff *skb, u32 pid, u32 seq, int event,
2935 int nowait, unsigned int flags)
2937 struct rtable *rt = skb_rtable(skb);
2939 struct nlmsghdr *nlh;
2940 unsigned long expires = 0;
2941 const struct inet_peer *peer = rt->peer;
2942 u32 id = 0, ts = 0, tsage = 0, error;
2944 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2948 r = nlmsg_data(nlh);
2949 r->rtm_family = AF_INET;
2950 r->rtm_dst_len = 32;
2952 r->rtm_tos = rt->rt_key_tos;
2953 r->rtm_table = RT_TABLE_MAIN;
2954 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2955 goto nla_put_failure;
2956 r->rtm_type = rt->rt_type;
2957 r->rtm_scope = RT_SCOPE_UNIVERSE;
2958 r->rtm_protocol = RTPROT_UNSPEC;
2959 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2960 if (rt->rt_flags & RTCF_NOTIFY)
2961 r->rtm_flags |= RTM_F_NOTIFY;
2963 if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2964 goto nla_put_failure;
2965 if (rt->rt_key_src) {
2966 r->rtm_src_len = 32;
2967 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src))
2968 goto nla_put_failure;
2971 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2972 goto nla_put_failure;
2973 #ifdef CONFIG_IP_ROUTE_CLASSID
2974 if (rt->dst.tclassid &&
2975 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2976 goto nla_put_failure;
2978 if (rt_is_input_route(rt)) {
2979 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_spec_dst))
2980 goto nla_put_failure;
2981 } else if (rt->rt_src != rt->rt_key_src) {
2982 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src))
2983 goto nla_put_failure;
2985 if (rt->rt_dst != rt->rt_gateway &&
2986 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2987 goto nla_put_failure;
2989 if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
2990 goto nla_put_failure;
2993 nla_put_be32(skb, RTA_MARK, rt->rt_mark))
2994 goto nla_put_failure;
2996 error = rt->dst.error;
2998 inet_peer_refcheck(rt->peer);
2999 id = atomic_read(&peer->ip_id_count) & 0xffff;
3000 if (peer->tcp_ts_stamp) {
3002 tsage = get_seconds() - peer->tcp_ts_stamp;
3004 expires = ACCESS_ONCE(peer->pmtu_expires);
3006 if (time_before(jiffies, expires))
3013 if (rt_is_input_route(rt)) {
3014 #ifdef CONFIG_IP_MROUTE
3015 __be32 dst = rt->rt_dst;
3017 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
3018 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
3019 int err = ipmr_get_route(net, skb,
3020 rt->rt_src, rt->rt_dst,
3026 goto nla_put_failure;
3028 if (err == -EMSGSIZE)
3029 goto nla_put_failure;
3035 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
3036 goto nla_put_failure;
3039 if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage,
3040 expires, error) < 0)
3041 goto nla_put_failure;
3043 return nlmsg_end(skb, nlh);
3046 nlmsg_cancel(skb, nlh);
3050 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
3052 struct net *net = sock_net(in_skb->sk);
3054 struct nlattr *tb[RTA_MAX+1];
3055 struct rtable *rt = NULL;
3061 struct sk_buff *skb;
3063 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
3067 rtm = nlmsg_data(nlh);
3069 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3075 /* Reserve room for dummy headers, this skb can pass
3076 through good chunk of routing engine.
3078 skb_reset_mac_header(skb);
3079 skb_reset_network_header(skb);
3081 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
3082 ip_hdr(skb)->protocol = IPPROTO_ICMP;
3083 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
3085 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
3086 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
3087 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3088 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3091 struct net_device *dev;
3093 dev = __dev_get_by_index(net, iif);
3099 skb->protocol = htons(ETH_P_IP);
3103 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
3106 rt = skb_rtable(skb);
3107 if (err == 0 && rt->dst.error)
3108 err = -rt->dst.error;
3110 struct flowi4 fl4 = {
3113 .flowi4_tos = rtm->rtm_tos,
3114 .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
3115 .flowi4_mark = mark,
3117 rt = ip_route_output_key(net, &fl4);
3127 skb_dst_set(skb, &rt->dst);
3128 if (rtm->rtm_flags & RTM_F_NOTIFY)
3129 rt->rt_flags |= RTCF_NOTIFY;
3131 err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
3132 RTM_NEWROUTE, 0, 0);
3136 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
3145 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
3152 net = sock_net(skb->sk);
3157 s_idx = idx = cb->args[1];
3158 for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
3159 if (!rt_hash_table[h].chain)
3162 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
3163 rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
3164 if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
3166 if (rt_is_expired(rt))
3168 skb_dst_set_noref(skb, &rt->dst);
3169 if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
3170 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
3171 1, NLM_F_MULTI) <= 0) {
3173 rcu_read_unlock_bh();
3178 rcu_read_unlock_bh();
3187 void ip_rt_multicast_event(struct in_device *in_dev)
3189 rt_cache_flush(dev_net(in_dev->dev), 0);
3192 #ifdef CONFIG_SYSCTL
3193 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
3194 void __user *buffer,
3195 size_t *lenp, loff_t *ppos)
3202 memcpy(&ctl, __ctl, sizeof(ctl));
3203 ctl.data = &flush_delay;
3204 proc_dointvec(&ctl, write, buffer, lenp, ppos);
3206 net = (struct net *)__ctl->extra1;
3207 rt_cache_flush(net, flush_delay);
3214 static ctl_table ipv4_route_table[] = {
3216 .procname = "gc_thresh",
3217 .data = &ipv4_dst_ops.gc_thresh,
3218 .maxlen = sizeof(int),
3220 .proc_handler = proc_dointvec,
3223 .procname = "max_size",
3224 .data = &ip_rt_max_size,
3225 .maxlen = sizeof(int),
3227 .proc_handler = proc_dointvec,
3230 /* Deprecated. Use gc_min_interval_ms */
3232 .procname = "gc_min_interval",
3233 .data = &ip_rt_gc_min_interval,
3234 .maxlen = sizeof(int),
3236 .proc_handler = proc_dointvec_jiffies,
3239 .procname = "gc_min_interval_ms",
3240 .data = &ip_rt_gc_min_interval,
3241 .maxlen = sizeof(int),
3243 .proc_handler = proc_dointvec_ms_jiffies,
3246 .procname = "gc_timeout",
3247 .data = &ip_rt_gc_timeout,
3248 .maxlen = sizeof(int),
3250 .proc_handler = proc_dointvec_jiffies,
3253 .procname = "gc_interval",
3254 .data = &ip_rt_gc_interval,
3255 .maxlen = sizeof(int),
3257 .proc_handler = proc_dointvec_jiffies,
3260 .procname = "redirect_load",
3261 .data = &ip_rt_redirect_load,
3262 .maxlen = sizeof(int),
3264 .proc_handler = proc_dointvec,
3267 .procname = "redirect_number",
3268 .data = &ip_rt_redirect_number,
3269 .maxlen = sizeof(int),
3271 .proc_handler = proc_dointvec,
3274 .procname = "redirect_silence",
3275 .data = &ip_rt_redirect_silence,
3276 .maxlen = sizeof(int),
3278 .proc_handler = proc_dointvec,
3281 .procname = "error_cost",
3282 .data = &ip_rt_error_cost,
3283 .maxlen = sizeof(int),
3285 .proc_handler = proc_dointvec,
3288 .procname = "error_burst",
3289 .data = &ip_rt_error_burst,
3290 .maxlen = sizeof(int),
3292 .proc_handler = proc_dointvec,
3295 .procname = "gc_elasticity",
3296 .data = &ip_rt_gc_elasticity,
3297 .maxlen = sizeof(int),
3299 .proc_handler = proc_dointvec,
3302 .procname = "mtu_expires",
3303 .data = &ip_rt_mtu_expires,
3304 .maxlen = sizeof(int),
3306 .proc_handler = proc_dointvec_jiffies,
3309 .procname = "min_pmtu",
3310 .data = &ip_rt_min_pmtu,
3311 .maxlen = sizeof(int),
3313 .proc_handler = proc_dointvec,
3316 .procname = "min_adv_mss",
3317 .data = &ip_rt_min_advmss,
3318 .maxlen = sizeof(int),
3320 .proc_handler = proc_dointvec,
3325 static struct ctl_table ipv4_route_flush_table[] = {
3327 .procname = "flush",
3328 .maxlen = sizeof(int),
3330 .proc_handler = ipv4_sysctl_rtcache_flush,
3335 static __net_init int sysctl_route_net_init(struct net *net)
3337 struct ctl_table *tbl;
3339 tbl = ipv4_route_flush_table;
3340 if (!net_eq(net, &init_net)) {
3341 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3345 tbl[0].extra1 = net;
3347 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3348 if (net->ipv4.route_hdr == NULL)
3353 if (tbl != ipv4_route_flush_table)
3359 static __net_exit void sysctl_route_net_exit(struct net *net)
3361 struct ctl_table *tbl;
3363 tbl = net->ipv4.route_hdr->ctl_table_arg;
3364 unregister_net_sysctl_table(net->ipv4.route_hdr);
3365 BUG_ON(tbl == ipv4_route_flush_table);
3369 static __net_initdata struct pernet_operations sysctl_route_ops = {
3370 .init = sysctl_route_net_init,
3371 .exit = sysctl_route_net_exit,
3375 static __net_init int rt_genid_init(struct net *net)
3377 get_random_bytes(&net->ipv4.rt_genid,
3378 sizeof(net->ipv4.rt_genid));
3379 get_random_bytes(&net->ipv4.dev_addr_genid,
3380 sizeof(net->ipv4.dev_addr_genid));
3384 static __net_initdata struct pernet_operations rt_genid_ops = {
3385 .init = rt_genid_init,
3389 #ifdef CONFIG_IP_ROUTE_CLASSID
3390 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3391 #endif /* CONFIG_IP_ROUTE_CLASSID */
3393 static __initdata unsigned long rhash_entries;
3394 static int __init set_rhash_entries(char *str)
3401 ret = kstrtoul(str, 0, &rhash_entries);
3407 __setup("rhash_entries=", set_rhash_entries);
3409 int __init ip_rt_init(void)
3413 #ifdef CONFIG_IP_ROUTE_CLASSID
3414 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3416 panic("IP: failed to allocate ip_rt_acct\n");
3419 ipv4_dst_ops.kmem_cachep =
3420 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3421 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3423 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3425 if (dst_entries_init(&ipv4_dst_ops) < 0)
3426 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3428 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3429 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3431 rt_hash_table = (struct rt_hash_bucket *)
3432 alloc_large_system_hash("IP route cache",
3433 sizeof(struct rt_hash_bucket),
3435 (totalram_pages >= 128 * 1024) ?
3441 rhash_entries ? 0 : 512 * 1024);
3442 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3443 rt_hash_lock_init();
3445 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3446 ip_rt_max_size = (rt_hash_mask + 1) * 16;
3451 INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3452 expires_ljiffies = jiffies;
3453 schedule_delayed_work(&expires_work,
3454 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3456 if (ip_rt_proc_init())
3457 pr_err("Unable to create route proc files\n");
3460 xfrm4_init(ip_rt_max_size);
3462 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3464 #ifdef CONFIG_SYSCTL
3465 register_pernet_subsys(&sysctl_route_ops);
3467 register_pernet_subsys(&rt_genid_ops);
3471 #ifdef CONFIG_SYSCTL
3473 * We really need to sanitize the damn ipv4 init order, then all
3474 * this nonsense will go away.
3476 void __init ip_static_sysctl_init(void)
3478 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);