ipv4: Kill 'rt_src' from 'struct rtable'
[~shefty/rdma-dev.git] / net / ipv4 / route.c
1 /*
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.
5  *
6  *              ROUTE - implementation of the IP router.
7  *
8  * Authors:     Ross Biro
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>
13  *
14  * Fixes:
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
24  *                                      clamper.
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.
39  *
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
58  *
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.
63  */
64
65 #define pr_fmt(fmt) "IPv4: " fmt
66
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>
72 #include <linux/mm.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>
78 #include <linux/in.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>
96 #include <net/dst.h>
97 #include <net/net_namespace.h>
98 #include <net/protocol.h>
99 #include <net/ip.h>
100 #include <net/route.h>
101 #include <net/inetpeer.h>
102 #include <net/sock.h>
103 #include <net/ip_fib.h>
104 #include <net/arp.h>
105 #include <net/tcp.h>
106 #include <net/icmp.h>
107 #include <net/xfrm.h>
108 #include <net/netevent.h>
109 #include <net/rtnetlink.h>
110 #ifdef CONFIG_SYSCTL
111 #include <linux/sysctl.h>
112 #include <linux/kmemleak.h>
113 #endif
114 #include <net/secure_seq.h>
115
116 #define RT_FL_TOS(oldflp4) \
117         ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
118
119 #define IP_MAX_MTU      0xFFF0
120
121 #define RT_GC_TIMEOUT (300*HZ)
122
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
137 /*
138  *      Interface to generic destination cache.
139  */
140
141 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
142 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
143 static unsigned int      ipv4_mtu(const struct dst_entry *dst);
144 static void              ipv4_dst_destroy(struct dst_entry *dst);
145 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
146 static void              ipv4_link_failure(struct sk_buff *skb);
147 static void              ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
148                                            struct sk_buff *skb, u32 mtu);
149 static void              ip_do_redirect(struct dst_entry *dst, struct sock *sk,
150                                         struct sk_buff *skb);
151
152 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
153                             int how)
154 {
155 }
156
157 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
158 {
159         WARN_ON(1);
160         return NULL;
161 }
162
163 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
164                                            struct sk_buff *skb,
165                                            const void *daddr);
166
167 static struct dst_ops ipv4_dst_ops = {
168         .family =               AF_INET,
169         .protocol =             cpu_to_be16(ETH_P_IP),
170         .check =                ipv4_dst_check,
171         .default_advmss =       ipv4_default_advmss,
172         .mtu =                  ipv4_mtu,
173         .cow_metrics =          ipv4_cow_metrics,
174         .destroy =              ipv4_dst_destroy,
175         .ifdown =               ipv4_dst_ifdown,
176         .negative_advice =      ipv4_negative_advice,
177         .link_failure =         ipv4_link_failure,
178         .update_pmtu =          ip_rt_update_pmtu,
179         .redirect =             ip_do_redirect,
180         .local_out =            __ip_local_out,
181         .neigh_lookup =         ipv4_neigh_lookup,
182 };
183
184 #define ECN_OR_COST(class)      TC_PRIO_##class
185
186 const __u8 ip_tos2prio[16] = {
187         TC_PRIO_BESTEFFORT,
188         ECN_OR_COST(BESTEFFORT),
189         TC_PRIO_BESTEFFORT,
190         ECN_OR_COST(BESTEFFORT),
191         TC_PRIO_BULK,
192         ECN_OR_COST(BULK),
193         TC_PRIO_BULK,
194         ECN_OR_COST(BULK),
195         TC_PRIO_INTERACTIVE,
196         ECN_OR_COST(INTERACTIVE),
197         TC_PRIO_INTERACTIVE,
198         ECN_OR_COST(INTERACTIVE),
199         TC_PRIO_INTERACTIVE_BULK,
200         ECN_OR_COST(INTERACTIVE_BULK),
201         TC_PRIO_INTERACTIVE_BULK,
202         ECN_OR_COST(INTERACTIVE_BULK)
203 };
204 EXPORT_SYMBOL(ip_tos2prio);
205
206 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
207 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
208
209 static inline int rt_genid(struct net *net)
210 {
211         return atomic_read(&net->ipv4.rt_genid);
212 }
213
214 #ifdef CONFIG_PROC_FS
215 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
216 {
217         if (*pos)
218                 return NULL;
219         return SEQ_START_TOKEN;
220 }
221
222 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
223 {
224         ++*pos;
225         return NULL;
226 }
227
228 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
229 {
230 }
231
232 static int rt_cache_seq_show(struct seq_file *seq, void *v)
233 {
234         if (v == SEQ_START_TOKEN)
235                 seq_printf(seq, "%-127s\n",
236                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
237                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
238                            "HHUptod\tSpecDst");
239         return 0;
240 }
241
242 static const struct seq_operations rt_cache_seq_ops = {
243         .start  = rt_cache_seq_start,
244         .next   = rt_cache_seq_next,
245         .stop   = rt_cache_seq_stop,
246         .show   = rt_cache_seq_show,
247 };
248
249 static int rt_cache_seq_open(struct inode *inode, struct file *file)
250 {
251         return seq_open(file, &rt_cache_seq_ops);
252 }
253
254 static const struct file_operations rt_cache_seq_fops = {
255         .owner   = THIS_MODULE,
256         .open    = rt_cache_seq_open,
257         .read    = seq_read,
258         .llseek  = seq_lseek,
259         .release = seq_release,
260 };
261
262
263 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
264 {
265         int cpu;
266
267         if (*pos == 0)
268                 return SEQ_START_TOKEN;
269
270         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
271                 if (!cpu_possible(cpu))
272                         continue;
273                 *pos = cpu+1;
274                 return &per_cpu(rt_cache_stat, cpu);
275         }
276         return NULL;
277 }
278
279 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
280 {
281         int cpu;
282
283         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
284                 if (!cpu_possible(cpu))
285                         continue;
286                 *pos = cpu+1;
287                 return &per_cpu(rt_cache_stat, cpu);
288         }
289         return NULL;
290
291 }
292
293 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
294 {
295
296 }
297
298 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
299 {
300         struct rt_cache_stat *st = v;
301
302         if (v == SEQ_START_TOKEN) {
303                 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");
304                 return 0;
305         }
306
307         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
308                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
309                    dst_entries_get_slow(&ipv4_dst_ops),
310                    st->in_hit,
311                    st->in_slow_tot,
312                    st->in_slow_mc,
313                    st->in_no_route,
314                    st->in_brd,
315                    st->in_martian_dst,
316                    st->in_martian_src,
317
318                    st->out_hit,
319                    st->out_slow_tot,
320                    st->out_slow_mc,
321
322                    st->gc_total,
323                    st->gc_ignored,
324                    st->gc_goal_miss,
325                    st->gc_dst_overflow,
326                    st->in_hlist_search,
327                    st->out_hlist_search
328                 );
329         return 0;
330 }
331
332 static const struct seq_operations rt_cpu_seq_ops = {
333         .start  = rt_cpu_seq_start,
334         .next   = rt_cpu_seq_next,
335         .stop   = rt_cpu_seq_stop,
336         .show   = rt_cpu_seq_show,
337 };
338
339
340 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
341 {
342         return seq_open(file, &rt_cpu_seq_ops);
343 }
344
345 static const struct file_operations rt_cpu_seq_fops = {
346         .owner   = THIS_MODULE,
347         .open    = rt_cpu_seq_open,
348         .read    = seq_read,
349         .llseek  = seq_lseek,
350         .release = seq_release,
351 };
352
353 #ifdef CONFIG_IP_ROUTE_CLASSID
354 static int rt_acct_proc_show(struct seq_file *m, void *v)
355 {
356         struct ip_rt_acct *dst, *src;
357         unsigned int i, j;
358
359         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
360         if (!dst)
361                 return -ENOMEM;
362
363         for_each_possible_cpu(i) {
364                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
365                 for (j = 0; j < 256; j++) {
366                         dst[j].o_bytes   += src[j].o_bytes;
367                         dst[j].o_packets += src[j].o_packets;
368                         dst[j].i_bytes   += src[j].i_bytes;
369                         dst[j].i_packets += src[j].i_packets;
370                 }
371         }
372
373         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
374         kfree(dst);
375         return 0;
376 }
377
378 static int rt_acct_proc_open(struct inode *inode, struct file *file)
379 {
380         return single_open(file, rt_acct_proc_show, NULL);
381 }
382
383 static const struct file_operations rt_acct_proc_fops = {
384         .owner          = THIS_MODULE,
385         .open           = rt_acct_proc_open,
386         .read           = seq_read,
387         .llseek         = seq_lseek,
388         .release        = single_release,
389 };
390 #endif
391
392 static int __net_init ip_rt_do_proc_init(struct net *net)
393 {
394         struct proc_dir_entry *pde;
395
396         pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
397                         &rt_cache_seq_fops);
398         if (!pde)
399                 goto err1;
400
401         pde = proc_create("rt_cache", S_IRUGO,
402                           net->proc_net_stat, &rt_cpu_seq_fops);
403         if (!pde)
404                 goto err2;
405
406 #ifdef CONFIG_IP_ROUTE_CLASSID
407         pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
408         if (!pde)
409                 goto err3;
410 #endif
411         return 0;
412
413 #ifdef CONFIG_IP_ROUTE_CLASSID
414 err3:
415         remove_proc_entry("rt_cache", net->proc_net_stat);
416 #endif
417 err2:
418         remove_proc_entry("rt_cache", net->proc_net);
419 err1:
420         return -ENOMEM;
421 }
422
423 static void __net_exit ip_rt_do_proc_exit(struct net *net)
424 {
425         remove_proc_entry("rt_cache", net->proc_net_stat);
426         remove_proc_entry("rt_cache", net->proc_net);
427 #ifdef CONFIG_IP_ROUTE_CLASSID
428         remove_proc_entry("rt_acct", net->proc_net);
429 #endif
430 }
431
432 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
433         .init = ip_rt_do_proc_init,
434         .exit = ip_rt_do_proc_exit,
435 };
436
437 static int __init ip_rt_proc_init(void)
438 {
439         return register_pernet_subsys(&ip_rt_proc_ops);
440 }
441
442 #else
443 static inline int ip_rt_proc_init(void)
444 {
445         return 0;
446 }
447 #endif /* CONFIG_PROC_FS */
448
449 static inline int rt_is_expired(struct rtable *rth)
450 {
451         return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
452 }
453
454 /*
455  * Perturbation of rt_genid by a small quantity [1..256]
456  * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
457  * many times (2^24) without giving recent rt_genid.
458  * Jenkins hash is strong enough that litle changes of rt_genid are OK.
459  */
460 static void rt_cache_invalidate(struct net *net)
461 {
462         unsigned char shuffle;
463
464         get_random_bytes(&shuffle, sizeof(shuffle));
465         atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
466 }
467
468 /*
469  * delay < 0  : invalidate cache (fast : entries will be deleted later)
470  * delay >= 0 : invalidate & flush cache (can be long)
471  */
472 void rt_cache_flush(struct net *net, int delay)
473 {
474         rt_cache_invalidate(net);
475 }
476
477 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
478                                            struct sk_buff *skb,
479                                            const void *daddr)
480 {
481         struct net_device *dev = dst->dev;
482         const __be32 *pkey = daddr;
483         const struct rtable *rt;
484         struct neighbour *n;
485
486         rt = (const struct rtable *) dst;
487         if (rt->rt_gateway)
488                 pkey = (const __be32 *) &rt->rt_gateway;
489         else if (skb)
490                 pkey = &ip_hdr(skb)->daddr;
491
492         n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
493         if (n)
494                 return n;
495         return neigh_create(&arp_tbl, pkey, dev);
496 }
497
498 /*
499  * Peer allocation may fail only in serious out-of-memory conditions.  However
500  * we still can generate some output.
501  * Random ID selection looks a bit dangerous because we have no chances to
502  * select ID being unique in a reasonable period of time.
503  * But broken packet identifier may be better than no packet at all.
504  */
505 static void ip_select_fb_ident(struct iphdr *iph)
506 {
507         static DEFINE_SPINLOCK(ip_fb_id_lock);
508         static u32 ip_fallback_id;
509         u32 salt;
510
511         spin_lock_bh(&ip_fb_id_lock);
512         salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
513         iph->id = htons(salt & 0xFFFF);
514         ip_fallback_id = salt;
515         spin_unlock_bh(&ip_fb_id_lock);
516 }
517
518 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
519 {
520         struct net *net = dev_net(dst->dev);
521         struct inet_peer *peer;
522
523         peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
524         if (peer) {
525                 iph->id = htons(inet_getid(peer, more));
526                 inet_putpeer(peer);
527                 return;
528         }
529
530         ip_select_fb_ident(iph);
531 }
532 EXPORT_SYMBOL(__ip_select_ident);
533
534 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
535                              const struct iphdr *iph,
536                              int oif, u8 tos,
537                              u8 prot, u32 mark, int flow_flags)
538 {
539         if (sk) {
540                 const struct inet_sock *inet = inet_sk(sk);
541
542                 oif = sk->sk_bound_dev_if;
543                 mark = sk->sk_mark;
544                 tos = RT_CONN_FLAGS(sk);
545                 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
546         }
547         flowi4_init_output(fl4, oif, mark, tos,
548                            RT_SCOPE_UNIVERSE, prot,
549                            flow_flags,
550                            iph->daddr, iph->saddr, 0, 0);
551 }
552
553 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
554                                const struct sock *sk)
555 {
556         const struct iphdr *iph = ip_hdr(skb);
557         int oif = skb->dev->ifindex;
558         u8 tos = RT_TOS(iph->tos);
559         u8 prot = iph->protocol;
560         u32 mark = skb->mark;
561
562         __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
563 }
564
565 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
566 {
567         const struct inet_sock *inet = inet_sk(sk);
568         const struct ip_options_rcu *inet_opt;
569         __be32 daddr = inet->inet_daddr;
570
571         rcu_read_lock();
572         inet_opt = rcu_dereference(inet->inet_opt);
573         if (inet_opt && inet_opt->opt.srr)
574                 daddr = inet_opt->opt.faddr;
575         flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
576                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
577                            inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
578                            inet_sk_flowi_flags(sk),
579                            daddr, inet->inet_saddr, 0, 0);
580         rcu_read_unlock();
581 }
582
583 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
584                                  const struct sk_buff *skb)
585 {
586         if (skb)
587                 build_skb_flow_key(fl4, skb, sk);
588         else
589                 build_sk_flow_key(fl4, sk);
590 }
591
592 static DEFINE_SEQLOCK(fnhe_seqlock);
593
594 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
595 {
596         struct fib_nh_exception *fnhe, *oldest;
597
598         oldest = rcu_dereference(hash->chain);
599         for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
600              fnhe = rcu_dereference(fnhe->fnhe_next)) {
601                 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
602                         oldest = fnhe;
603         }
604         return oldest;
605 }
606
607 static inline u32 fnhe_hashfun(__be32 daddr)
608 {
609         u32 hval;
610
611         hval = (__force u32) daddr;
612         hval ^= (hval >> 11) ^ (hval >> 22);
613
614         return hval & (FNHE_HASH_SIZE - 1);
615 }
616
617 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
618                                   u32 pmtu, unsigned long expires)
619 {
620         struct fnhe_hash_bucket *hash;
621         struct fib_nh_exception *fnhe;
622         int depth;
623         u32 hval = fnhe_hashfun(daddr);
624
625         write_seqlock_bh(&fnhe_seqlock);
626
627         hash = nh->nh_exceptions;
628         if (!hash) {
629                 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
630                 if (!hash)
631                         goto out_unlock;
632                 nh->nh_exceptions = hash;
633         }
634
635         hash += hval;
636
637         depth = 0;
638         for (fnhe = rcu_dereference(hash->chain); fnhe;
639              fnhe = rcu_dereference(fnhe->fnhe_next)) {
640                 if (fnhe->fnhe_daddr == daddr)
641                         break;
642                 depth++;
643         }
644
645         if (fnhe) {
646                 if (gw)
647                         fnhe->fnhe_gw = gw;
648                 if (pmtu) {
649                         fnhe->fnhe_pmtu = pmtu;
650                         fnhe->fnhe_expires = expires;
651                 }
652         } else {
653                 if (depth > FNHE_RECLAIM_DEPTH)
654                         fnhe = fnhe_oldest(hash);
655                 else {
656                         fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
657                         if (!fnhe)
658                                 goto out_unlock;
659
660                         fnhe->fnhe_next = hash->chain;
661                         rcu_assign_pointer(hash->chain, fnhe);
662                 }
663                 fnhe->fnhe_daddr = daddr;
664                 fnhe->fnhe_gw = gw;
665                 fnhe->fnhe_pmtu = pmtu;
666                 fnhe->fnhe_expires = expires;
667         }
668
669         fnhe->fnhe_stamp = jiffies;
670
671 out_unlock:
672         write_sequnlock_bh(&fnhe_seqlock);
673         return;
674 }
675
676 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4)
677 {
678         __be32 new_gw = icmp_hdr(skb)->un.gateway;
679         __be32 old_gw = ip_hdr(skb)->saddr;
680         struct net_device *dev = skb->dev;
681         struct in_device *in_dev;
682         struct fib_result res;
683         struct neighbour *n;
684         struct net *net;
685
686         switch (icmp_hdr(skb)->code & 7) {
687         case ICMP_REDIR_NET:
688         case ICMP_REDIR_NETTOS:
689         case ICMP_REDIR_HOST:
690         case ICMP_REDIR_HOSTTOS:
691                 break;
692
693         default:
694                 return;
695         }
696
697         if (rt->rt_gateway != old_gw)
698                 return;
699
700         in_dev = __in_dev_get_rcu(dev);
701         if (!in_dev)
702                 return;
703
704         net = dev_net(dev);
705         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
706             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
707             ipv4_is_zeronet(new_gw))
708                 goto reject_redirect;
709
710         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
711                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
712                         goto reject_redirect;
713                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
714                         goto reject_redirect;
715         } else {
716                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
717                         goto reject_redirect;
718         }
719
720         n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
721         if (n) {
722                 if (!(n->nud_state & NUD_VALID)) {
723                         neigh_event_send(n, NULL);
724                 } else {
725                         if (fib_lookup(net, fl4, &res) == 0) {
726                                 struct fib_nh *nh = &FIB_RES_NH(res);
727
728                                 update_or_create_fnhe(nh, fl4->daddr, new_gw,
729                                                       0, 0);
730                         }
731                         rt->rt_gateway = new_gw;
732                         rt->rt_flags |= RTCF_REDIRECTED;
733                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
734                 }
735                 neigh_release(n);
736         }
737         return;
738
739 reject_redirect:
740 #ifdef CONFIG_IP_ROUTE_VERBOSE
741         if (IN_DEV_LOG_MARTIANS(in_dev)) {
742                 const struct iphdr *iph = (const struct iphdr *) skb->data;
743                 __be32 daddr = iph->daddr;
744                 __be32 saddr = iph->saddr;
745
746                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
747                                      "  Advised path = %pI4 -> %pI4\n",
748                                      &old_gw, dev->name, &new_gw,
749                                      &saddr, &daddr);
750         }
751 #endif
752         ;
753 }
754
755 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
756 {
757         struct rtable *rt;
758         struct flowi4 fl4;
759
760         rt = (struct rtable *) dst;
761
762         ip_rt_build_flow_key(&fl4, sk, skb);
763         __ip_do_redirect(rt, skb, &fl4);
764 }
765
766 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
767 {
768         struct rtable *rt = (struct rtable *)dst;
769         struct dst_entry *ret = dst;
770
771         if (rt) {
772                 if (dst->obsolete > 0) {
773                         ip_rt_put(rt);
774                         ret = NULL;
775                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
776                            rt->dst.expires) {
777                         ip_rt_put(rt);
778                         ret = NULL;
779                 }
780         }
781         return ret;
782 }
783
784 /*
785  * Algorithm:
786  *      1. The first ip_rt_redirect_number redirects are sent
787  *         with exponential backoff, then we stop sending them at all,
788  *         assuming that the host ignores our redirects.
789  *      2. If we did not see packets requiring redirects
790  *         during ip_rt_redirect_silence, we assume that the host
791  *         forgot redirected route and start to send redirects again.
792  *
793  * This algorithm is much cheaper and more intelligent than dumb load limiting
794  * in icmp.c.
795  *
796  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
797  * and "frag. need" (breaks PMTU discovery) in icmp.c.
798  */
799
800 void ip_rt_send_redirect(struct sk_buff *skb)
801 {
802         struct rtable *rt = skb_rtable(skb);
803         struct in_device *in_dev;
804         struct inet_peer *peer;
805         struct net *net;
806         int log_martians;
807
808         rcu_read_lock();
809         in_dev = __in_dev_get_rcu(rt->dst.dev);
810         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
811                 rcu_read_unlock();
812                 return;
813         }
814         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
815         rcu_read_unlock();
816
817         net = dev_net(rt->dst.dev);
818         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
819         if (!peer) {
820                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
821                 return;
822         }
823
824         /* No redirected packets during ip_rt_redirect_silence;
825          * reset the algorithm.
826          */
827         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
828                 peer->rate_tokens = 0;
829
830         /* Too many ignored redirects; do not send anything
831          * set dst.rate_last to the last seen redirected packet.
832          */
833         if (peer->rate_tokens >= ip_rt_redirect_number) {
834                 peer->rate_last = jiffies;
835                 goto out_put_peer;
836         }
837
838         /* Check for load limit; set rate_last to the latest sent
839          * redirect.
840          */
841         if (peer->rate_tokens == 0 ||
842             time_after(jiffies,
843                        (peer->rate_last +
844                         (ip_rt_redirect_load << peer->rate_tokens)))) {
845                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
846                 peer->rate_last = jiffies;
847                 ++peer->rate_tokens;
848 #ifdef CONFIG_IP_ROUTE_VERBOSE
849                 if (log_martians &&
850                     peer->rate_tokens == ip_rt_redirect_number)
851                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
852                                              &ip_hdr(skb)->saddr, rt->rt_iif,
853                                              &rt->rt_dst, &rt->rt_gateway);
854 #endif
855         }
856 out_put_peer:
857         inet_putpeer(peer);
858 }
859
860 static int ip_error(struct sk_buff *skb)
861 {
862         struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
863         struct rtable *rt = skb_rtable(skb);
864         struct inet_peer *peer;
865         unsigned long now;
866         struct net *net;
867         bool send;
868         int code;
869
870         net = dev_net(rt->dst.dev);
871         if (!IN_DEV_FORWARD(in_dev)) {
872                 switch (rt->dst.error) {
873                 case EHOSTUNREACH:
874                         IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
875                         break;
876
877                 case ENETUNREACH:
878                         IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
879                         break;
880                 }
881                 goto out;
882         }
883
884         switch (rt->dst.error) {
885         case EINVAL:
886         default:
887                 goto out;
888         case EHOSTUNREACH:
889                 code = ICMP_HOST_UNREACH;
890                 break;
891         case ENETUNREACH:
892                 code = ICMP_NET_UNREACH;
893                 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
894                 break;
895         case EACCES:
896                 code = ICMP_PKT_FILTERED;
897                 break;
898         }
899
900         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
901
902         send = true;
903         if (peer) {
904                 now = jiffies;
905                 peer->rate_tokens += now - peer->rate_last;
906                 if (peer->rate_tokens > ip_rt_error_burst)
907                         peer->rate_tokens = ip_rt_error_burst;
908                 peer->rate_last = now;
909                 if (peer->rate_tokens >= ip_rt_error_cost)
910                         peer->rate_tokens -= ip_rt_error_cost;
911                 else
912                         send = false;
913                 inet_putpeer(peer);
914         }
915         if (send)
916                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
917
918 out:    kfree_skb(skb);
919         return 0;
920 }
921
922 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
923 {
924         struct fib_result res;
925
926         if (mtu < ip_rt_min_pmtu)
927                 mtu = ip_rt_min_pmtu;
928
929         if (fib_lookup(dev_net(rt->dst.dev), fl4, &res) == 0) {
930                 struct fib_nh *nh = &FIB_RES_NH(res);
931
932                 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
933                                       jiffies + ip_rt_mtu_expires);
934         }
935         rt->rt_pmtu = mtu;
936         dst_set_expires(&rt->dst, ip_rt_mtu_expires);
937 }
938
939 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
940                               struct sk_buff *skb, u32 mtu)
941 {
942         struct rtable *rt = (struct rtable *) dst;
943         struct flowi4 fl4;
944
945         ip_rt_build_flow_key(&fl4, sk, skb);
946         __ip_rt_update_pmtu(rt, &fl4, mtu);
947 }
948
949 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
950                       int oif, u32 mark, u8 protocol, int flow_flags)
951 {
952         const struct iphdr *iph = (const struct iphdr *) skb->data;
953         struct flowi4 fl4;
954         struct rtable *rt;
955
956         __build_flow_key(&fl4, NULL, iph, oif,
957                          RT_TOS(iph->tos), protocol, mark, flow_flags);
958         rt = __ip_route_output_key(net, &fl4);
959         if (!IS_ERR(rt)) {
960                 __ip_rt_update_pmtu(rt, &fl4, mtu);
961                 ip_rt_put(rt);
962         }
963 }
964 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
965
966 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
967 {
968         const struct iphdr *iph = (const struct iphdr *) skb->data;
969         struct flowi4 fl4;
970         struct rtable *rt;
971
972         __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
973         rt = __ip_route_output_key(sock_net(sk), &fl4);
974         if (!IS_ERR(rt)) {
975                 __ip_rt_update_pmtu(rt, &fl4, mtu);
976                 ip_rt_put(rt);
977         }
978 }
979 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
980
981 void ipv4_redirect(struct sk_buff *skb, struct net *net,
982                    int oif, u32 mark, u8 protocol, int flow_flags)
983 {
984         const struct iphdr *iph = (const struct iphdr *) skb->data;
985         struct flowi4 fl4;
986         struct rtable *rt;
987
988         __build_flow_key(&fl4, NULL, iph, oif,
989                          RT_TOS(iph->tos), protocol, mark, flow_flags);
990         rt = __ip_route_output_key(net, &fl4);
991         if (!IS_ERR(rt)) {
992                 __ip_do_redirect(rt, skb, &fl4);
993                 ip_rt_put(rt);
994         }
995 }
996 EXPORT_SYMBOL_GPL(ipv4_redirect);
997
998 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
999 {
1000         const struct iphdr *iph = (const struct iphdr *) skb->data;
1001         struct flowi4 fl4;
1002         struct rtable *rt;
1003
1004         __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1005         rt = __ip_route_output_key(sock_net(sk), &fl4);
1006         if (!IS_ERR(rt)) {
1007                 __ip_do_redirect(rt, skb, &fl4);
1008                 ip_rt_put(rt);
1009         }
1010 }
1011 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1012
1013 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1014 {
1015         struct rtable *rt = (struct rtable *) dst;
1016
1017         if (rt_is_expired(rt))
1018                 return NULL;
1019         return dst;
1020 }
1021
1022 static void ipv4_dst_destroy(struct dst_entry *dst)
1023 {
1024         struct rtable *rt = (struct rtable *) dst;
1025
1026         if (rt->fi) {
1027                 fib_info_put(rt->fi);
1028                 rt->fi = NULL;
1029         }
1030 }
1031
1032
1033 static void ipv4_link_failure(struct sk_buff *skb)
1034 {
1035         struct rtable *rt;
1036
1037         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1038
1039         rt = skb_rtable(skb);
1040         if (rt)
1041                 dst_set_expires(&rt->dst, 0);
1042 }
1043
1044 static int ip_rt_bug(struct sk_buff *skb)
1045 {
1046         pr_debug("%s: %pI4 -> %pI4, %s\n",
1047                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1048                  skb->dev ? skb->dev->name : "?");
1049         kfree_skb(skb);
1050         WARN_ON(1);
1051         return 0;
1052 }
1053
1054 /*
1055    We do not cache source address of outgoing interface,
1056    because it is used only by IP RR, TS and SRR options,
1057    so that it out of fast path.
1058
1059    BTW remember: "addr" is allowed to be not aligned
1060    in IP options!
1061  */
1062
1063 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1064 {
1065         __be32 src;
1066
1067         if (rt_is_output_route(rt))
1068                 src = ip_hdr(skb)->saddr;
1069         else {
1070                 struct fib_result res;
1071                 struct flowi4 fl4;
1072                 struct iphdr *iph;
1073
1074                 iph = ip_hdr(skb);
1075
1076                 memset(&fl4, 0, sizeof(fl4));
1077                 fl4.daddr = iph->daddr;
1078                 fl4.saddr = iph->saddr;
1079                 fl4.flowi4_tos = RT_TOS(iph->tos);
1080                 fl4.flowi4_oif = rt->dst.dev->ifindex;
1081                 fl4.flowi4_iif = skb->dev->ifindex;
1082                 fl4.flowi4_mark = skb->mark;
1083
1084                 rcu_read_lock();
1085                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1086                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1087                 else
1088                         src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1089                                         RT_SCOPE_UNIVERSE);
1090                 rcu_read_unlock();
1091         }
1092         memcpy(addr, &src, 4);
1093 }
1094
1095 #ifdef CONFIG_IP_ROUTE_CLASSID
1096 static void set_class_tag(struct rtable *rt, u32 tag)
1097 {
1098         if (!(rt->dst.tclassid & 0xFFFF))
1099                 rt->dst.tclassid |= tag & 0xFFFF;
1100         if (!(rt->dst.tclassid & 0xFFFF0000))
1101                 rt->dst.tclassid |= tag & 0xFFFF0000;
1102 }
1103 #endif
1104
1105 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1106 {
1107         unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1108
1109         if (advmss == 0) {
1110                 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1111                                ip_rt_min_advmss);
1112                 if (advmss > 65535 - 40)
1113                         advmss = 65535 - 40;
1114         }
1115         return advmss;
1116 }
1117
1118 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1119 {
1120         const struct rtable *rt = (const struct rtable *) dst;
1121         unsigned int mtu = rt->rt_pmtu;
1122
1123         if (mtu && time_after_eq(jiffies, rt->dst.expires))
1124                 mtu = 0;
1125
1126         if (!mtu)
1127                 mtu = dst_metric_raw(dst, RTAX_MTU);
1128
1129         if (mtu && rt_is_output_route(rt))
1130                 return mtu;
1131
1132         mtu = dst->dev->mtu;
1133
1134         if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1135
1136                 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1137                         mtu = 576;
1138         }
1139
1140         if (mtu > IP_MAX_MTU)
1141                 mtu = IP_MAX_MTU;
1142
1143         return mtu;
1144 }
1145
1146 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1147                             struct fib_info *fi)
1148 {
1149         if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1150                 rt->fi = fi;
1151                 atomic_inc(&fi->fib_clntref);
1152         }
1153         dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1154 }
1155
1156 static void rt_bind_exception(struct rtable *rt, struct fib_nh *nh, __be32 daddr)
1157 {
1158         struct fnhe_hash_bucket *hash = nh->nh_exceptions;
1159         struct fib_nh_exception *fnhe;
1160         u32 hval;
1161
1162         hval = fnhe_hashfun(daddr);
1163
1164 restart:
1165         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1166              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1167                 __be32 fnhe_daddr, gw;
1168                 unsigned long expires;
1169                 unsigned int seq;
1170                 u32 pmtu;
1171
1172                 seq = read_seqbegin(&fnhe_seqlock);
1173                 fnhe_daddr = fnhe->fnhe_daddr;
1174                 gw = fnhe->fnhe_gw;
1175                 pmtu = fnhe->fnhe_pmtu;
1176                 expires = fnhe->fnhe_expires;
1177                 if (read_seqretry(&fnhe_seqlock, seq))
1178                         goto restart;
1179                 if (daddr != fnhe_daddr)
1180                         continue;
1181                 if (pmtu) {
1182                         unsigned long diff = expires - jiffies;
1183
1184                         if (time_before(jiffies, expires)) {
1185                                 rt->rt_pmtu = pmtu;
1186                                 dst_set_expires(&rt->dst, diff);
1187                         }
1188                 }
1189                 if (gw)
1190                         rt->rt_gateway = gw;
1191                 fnhe->fnhe_stamp = jiffies;
1192                 break;
1193         }
1194 }
1195
1196 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1197                            const struct fib_result *res,
1198                            struct fib_info *fi, u16 type, u32 itag)
1199 {
1200         if (fi) {
1201                 struct fib_nh *nh = &FIB_RES_NH(*res);
1202
1203                 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK)
1204                         rt->rt_gateway = nh->nh_gw;
1205                 if (unlikely(nh->nh_exceptions))
1206                         rt_bind_exception(rt, nh, fl4->daddr);
1207                 rt_init_metrics(rt, fl4, fi);
1208 #ifdef CONFIG_IP_ROUTE_CLASSID
1209                 rt->dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1210 #endif
1211         }
1212
1213 #ifdef CONFIG_IP_ROUTE_CLASSID
1214 #ifdef CONFIG_IP_MULTIPLE_TABLES
1215         set_class_tag(rt, res->tclassid);
1216 #endif
1217         set_class_tag(rt, itag);
1218 #endif
1219 }
1220
1221 static struct rtable *rt_dst_alloc(struct net_device *dev,
1222                                    bool nopolicy, bool noxfrm)
1223 {
1224         return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
1225                          DST_HOST | DST_NOCACHE |
1226                          (nopolicy ? DST_NOPOLICY : 0) |
1227                          (noxfrm ? DST_NOXFRM : 0));
1228 }
1229
1230 /* called in rcu_read_lock() section */
1231 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1232                                 u8 tos, struct net_device *dev, int our)
1233 {
1234         struct rtable *rth;
1235         struct in_device *in_dev = __in_dev_get_rcu(dev);
1236         u32 itag = 0;
1237         int err;
1238
1239         /* Primary sanity checks. */
1240
1241         if (in_dev == NULL)
1242                 return -EINVAL;
1243
1244         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1245             skb->protocol != htons(ETH_P_IP))
1246                 goto e_inval;
1247
1248         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1249                 if (ipv4_is_loopback(saddr))
1250                         goto e_inval;
1251
1252         if (ipv4_is_zeronet(saddr)) {
1253                 if (!ipv4_is_local_multicast(daddr))
1254                         goto e_inval;
1255         } else {
1256                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1257                                           in_dev, &itag);
1258                 if (err < 0)
1259                         goto e_err;
1260         }
1261         rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1262                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
1263         if (!rth)
1264                 goto e_nobufs;
1265
1266 #ifdef CONFIG_IP_ROUTE_CLASSID
1267         rth->dst.tclassid = itag;
1268 #endif
1269         rth->dst.output = ip_rt_bug;
1270
1271         rth->rt_genid   = rt_genid(dev_net(dev));
1272         rth->rt_flags   = RTCF_MULTICAST;
1273         rth->rt_type    = RTN_MULTICAST;
1274         rth->rt_dst     = daddr;
1275         rth->rt_route_iif = dev->ifindex;
1276         rth->rt_iif     = dev->ifindex;
1277         rth->rt_oif     = 0;
1278         rth->rt_mark    = skb->mark;
1279         rth->rt_pmtu    = 0;
1280         rth->rt_gateway = daddr;
1281         rth->fi = NULL;
1282         if (our) {
1283                 rth->dst.input= ip_local_deliver;
1284                 rth->rt_flags |= RTCF_LOCAL;
1285         }
1286
1287 #ifdef CONFIG_IP_MROUTE
1288         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1289                 rth->dst.input = ip_mr_input;
1290 #endif
1291         RT_CACHE_STAT_INC(in_slow_mc);
1292
1293         skb_dst_set(skb, &rth->dst);
1294         return 0;
1295
1296 e_nobufs:
1297         return -ENOBUFS;
1298 e_inval:
1299         return -EINVAL;
1300 e_err:
1301         return err;
1302 }
1303
1304
1305 static void ip_handle_martian_source(struct net_device *dev,
1306                                      struct in_device *in_dev,
1307                                      struct sk_buff *skb,
1308                                      __be32 daddr,
1309                                      __be32 saddr)
1310 {
1311         RT_CACHE_STAT_INC(in_martian_src);
1312 #ifdef CONFIG_IP_ROUTE_VERBOSE
1313         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1314                 /*
1315                  *      RFC1812 recommendation, if source is martian,
1316                  *      the only hint is MAC header.
1317                  */
1318                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1319                         &daddr, &saddr, dev->name);
1320                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1321                         print_hex_dump(KERN_WARNING, "ll header: ",
1322                                        DUMP_PREFIX_OFFSET, 16, 1,
1323                                        skb_mac_header(skb),
1324                                        dev->hard_header_len, true);
1325                 }
1326         }
1327 #endif
1328 }
1329
1330 /* called in rcu_read_lock() section */
1331 static int __mkroute_input(struct sk_buff *skb,
1332                            const struct fib_result *res,
1333                            struct in_device *in_dev,
1334                            __be32 daddr, __be32 saddr, u32 tos,
1335                            struct rtable **result)
1336 {
1337         struct rtable *rth;
1338         int err;
1339         struct in_device *out_dev;
1340         unsigned int flags = 0;
1341         u32 itag;
1342
1343         /* get a working reference to the output device */
1344         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1345         if (out_dev == NULL) {
1346                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1347                 return -EINVAL;
1348         }
1349
1350
1351         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1352                                   in_dev->dev, in_dev, &itag);
1353         if (err < 0) {
1354                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1355                                          saddr);
1356
1357                 goto cleanup;
1358         }
1359
1360         if (err)
1361                 flags |= RTCF_DIRECTSRC;
1362
1363         if (out_dev == in_dev && err &&
1364             (IN_DEV_SHARED_MEDIA(out_dev) ||
1365              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1366                 flags |= RTCF_DOREDIRECT;
1367
1368         if (skb->protocol != htons(ETH_P_IP)) {
1369                 /* Not IP (i.e. ARP). Do not create route, if it is
1370                  * invalid for proxy arp. DNAT routes are always valid.
1371                  *
1372                  * Proxy arp feature have been extended to allow, ARP
1373                  * replies back to the same interface, to support
1374                  * Private VLAN switch technologies. See arp.c.
1375                  */
1376                 if (out_dev == in_dev &&
1377                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1378                         err = -EINVAL;
1379                         goto cleanup;
1380                 }
1381         }
1382
1383         rth = rt_dst_alloc(out_dev->dev,
1384                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1385                            IN_DEV_CONF_GET(out_dev, NOXFRM));
1386         if (!rth) {
1387                 err = -ENOBUFS;
1388                 goto cleanup;
1389         }
1390
1391         rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
1392         rth->rt_flags = flags;
1393         rth->rt_type = res->type;
1394         rth->rt_dst     = daddr;
1395         rth->rt_route_iif = in_dev->dev->ifindex;
1396         rth->rt_iif     = in_dev->dev->ifindex;
1397         rth->rt_oif     = 0;
1398         rth->rt_mark    = skb->mark;
1399         rth->rt_pmtu    = 0;
1400         rth->rt_gateway = daddr;
1401         rth->fi = NULL;
1402
1403         rth->dst.input = ip_forward;
1404         rth->dst.output = ip_output;
1405
1406         rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
1407
1408         *result = rth;
1409         err = 0;
1410  cleanup:
1411         return err;
1412 }
1413
1414 static int ip_mkroute_input(struct sk_buff *skb,
1415                             struct fib_result *res,
1416                             const struct flowi4 *fl4,
1417                             struct in_device *in_dev,
1418                             __be32 daddr, __be32 saddr, u32 tos)
1419 {
1420         struct rtable *rth = NULL;
1421         int err;
1422
1423 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1424         if (res->fi && res->fi->fib_nhs > 1)
1425                 fib_select_multipath(res);
1426 #endif
1427
1428         /* create a routing cache entry */
1429         err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1430         if (err)
1431                 return err;
1432
1433         skb_dst_set(skb, &rth->dst);
1434         return 0;
1435 }
1436
1437 /*
1438  *      NOTE. We drop all the packets that has local source
1439  *      addresses, because every properly looped back packet
1440  *      must have correct destination already attached by output routine.
1441  *
1442  *      Such approach solves two big problems:
1443  *      1. Not simplex devices are handled properly.
1444  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1445  *      called with rcu_read_lock()
1446  */
1447
1448 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1449                                u8 tos, struct net_device *dev)
1450 {
1451         struct fib_result res;
1452         struct in_device *in_dev = __in_dev_get_rcu(dev);
1453         struct flowi4   fl4;
1454         unsigned int    flags = 0;
1455         u32             itag = 0;
1456         struct rtable   *rth;
1457         int             err = -EINVAL;
1458         struct net    *net = dev_net(dev);
1459
1460         /* IP on this device is disabled. */
1461
1462         if (!in_dev)
1463                 goto out;
1464
1465         /* Check for the most weird martians, which can be not detected
1466            by fib_lookup.
1467          */
1468
1469         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1470                 goto martian_source;
1471
1472         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1473                 goto brd_input;
1474
1475         /* Accept zero addresses only to limited broadcast;
1476          * I even do not know to fix it or not. Waiting for complains :-)
1477          */
1478         if (ipv4_is_zeronet(saddr))
1479                 goto martian_source;
1480
1481         if (ipv4_is_zeronet(daddr))
1482                 goto martian_destination;
1483
1484         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
1485                 if (ipv4_is_loopback(daddr))
1486                         goto martian_destination;
1487
1488                 if (ipv4_is_loopback(saddr))
1489                         goto martian_source;
1490         }
1491
1492         /*
1493          *      Now we are ready to route packet.
1494          */
1495         fl4.flowi4_oif = 0;
1496         fl4.flowi4_iif = dev->ifindex;
1497         fl4.flowi4_mark = skb->mark;
1498         fl4.flowi4_tos = tos;
1499         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1500         fl4.daddr = daddr;
1501         fl4.saddr = saddr;
1502         err = fib_lookup(net, &fl4, &res);
1503         if (err != 0)
1504                 goto no_route;
1505
1506         RT_CACHE_STAT_INC(in_slow_tot);
1507
1508         if (res.type == RTN_BROADCAST)
1509                 goto brd_input;
1510
1511         if (res.type == RTN_LOCAL) {
1512                 err = fib_validate_source(skb, saddr, daddr, tos,
1513                                           net->loopback_dev->ifindex,
1514                                           dev, in_dev, &itag);
1515                 if (err < 0)
1516                         goto martian_source_keep_err;
1517                 if (err)
1518                         flags |= RTCF_DIRECTSRC;
1519                 goto local_input;
1520         }
1521
1522         if (!IN_DEV_FORWARD(in_dev))
1523                 goto no_route;
1524         if (res.type != RTN_UNICAST)
1525                 goto martian_destination;
1526
1527         err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1528 out:    return err;
1529
1530 brd_input:
1531         if (skb->protocol != htons(ETH_P_IP))
1532                 goto e_inval;
1533
1534         if (!ipv4_is_zeronet(saddr)) {
1535                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1536                                           in_dev, &itag);
1537                 if (err < 0)
1538                         goto martian_source_keep_err;
1539                 if (err)
1540                         flags |= RTCF_DIRECTSRC;
1541         }
1542         flags |= RTCF_BROADCAST;
1543         res.type = RTN_BROADCAST;
1544         RT_CACHE_STAT_INC(in_brd);
1545
1546 local_input:
1547         rth = rt_dst_alloc(net->loopback_dev,
1548                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
1549         if (!rth)
1550                 goto e_nobufs;
1551
1552         rth->dst.input= ip_local_deliver;
1553         rth->dst.output= ip_rt_bug;
1554 #ifdef CONFIG_IP_ROUTE_CLASSID
1555         rth->dst.tclassid = itag;
1556 #endif
1557
1558         rth->rt_genid = rt_genid(net);
1559         rth->rt_flags   = flags|RTCF_LOCAL;
1560         rth->rt_type    = res.type;
1561         rth->rt_dst     = daddr;
1562         rth->rt_route_iif = dev->ifindex;
1563         rth->rt_iif     = dev->ifindex;
1564         rth->rt_oif     = 0;
1565         rth->rt_mark    = skb->mark;
1566         rth->rt_pmtu    = 0;
1567         rth->rt_gateway = daddr;
1568         rth->fi = NULL;
1569         if (res.type == RTN_UNREACHABLE) {
1570                 rth->dst.input= ip_error;
1571                 rth->dst.error= -err;
1572                 rth->rt_flags   &= ~RTCF_LOCAL;
1573         }
1574         skb_dst_set(skb, &rth->dst);
1575         err = 0;
1576         goto out;
1577
1578 no_route:
1579         RT_CACHE_STAT_INC(in_no_route);
1580         res.type = RTN_UNREACHABLE;
1581         if (err == -ESRCH)
1582                 err = -ENETUNREACH;
1583         goto local_input;
1584
1585         /*
1586          *      Do not cache martian addresses: they should be logged (RFC1812)
1587          */
1588 martian_destination:
1589         RT_CACHE_STAT_INC(in_martian_dst);
1590 #ifdef CONFIG_IP_ROUTE_VERBOSE
1591         if (IN_DEV_LOG_MARTIANS(in_dev))
1592                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1593                                      &daddr, &saddr, dev->name);
1594 #endif
1595
1596 e_inval:
1597         err = -EINVAL;
1598         goto out;
1599
1600 e_nobufs:
1601         err = -ENOBUFS;
1602         goto out;
1603
1604 martian_source:
1605         err = -EINVAL;
1606 martian_source_keep_err:
1607         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1608         goto out;
1609 }
1610
1611 int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1612                    u8 tos, struct net_device *dev)
1613 {
1614         int res;
1615
1616         rcu_read_lock();
1617
1618         /* Multicast recognition logic is moved from route cache to here.
1619            The problem was that too many Ethernet cards have broken/missing
1620            hardware multicast filters :-( As result the host on multicasting
1621            network acquires a lot of useless route cache entries, sort of
1622            SDR messages from all the world. Now we try to get rid of them.
1623            Really, provided software IP multicast filter is organized
1624            reasonably (at least, hashed), it does not result in a slowdown
1625            comparing with route cache reject entries.
1626            Note, that multicast routers are not affected, because
1627            route cache entry is created eventually.
1628          */
1629         if (ipv4_is_multicast(daddr)) {
1630                 struct in_device *in_dev = __in_dev_get_rcu(dev);
1631
1632                 if (in_dev) {
1633                         int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1634                                                   ip_hdr(skb)->protocol);
1635                         if (our
1636 #ifdef CONFIG_IP_MROUTE
1637                                 ||
1638                             (!ipv4_is_local_multicast(daddr) &&
1639                              IN_DEV_MFORWARD(in_dev))
1640 #endif
1641                            ) {
1642                                 int res = ip_route_input_mc(skb, daddr, saddr,
1643                                                             tos, dev, our);
1644                                 rcu_read_unlock();
1645                                 return res;
1646                         }
1647                 }
1648                 rcu_read_unlock();
1649                 return -EINVAL;
1650         }
1651         res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1652         rcu_read_unlock();
1653         return res;
1654 }
1655 EXPORT_SYMBOL(ip_route_input);
1656
1657 /* called with rcu_read_lock() */
1658 static struct rtable *__mkroute_output(const struct fib_result *res,
1659                                        const struct flowi4 *fl4, int orig_oif,
1660                                        struct net_device *dev_out,
1661                                        unsigned int flags)
1662 {
1663         struct fib_info *fi = res->fi;
1664         struct in_device *in_dev;
1665         u16 type = res->type;
1666         struct rtable *rth;
1667
1668         in_dev = __in_dev_get_rcu(dev_out);
1669         if (!in_dev)
1670                 return ERR_PTR(-EINVAL);
1671
1672         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1673                 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
1674                         return ERR_PTR(-EINVAL);
1675
1676         if (ipv4_is_lbcast(fl4->daddr))
1677                 type = RTN_BROADCAST;
1678         else if (ipv4_is_multicast(fl4->daddr))
1679                 type = RTN_MULTICAST;
1680         else if (ipv4_is_zeronet(fl4->daddr))
1681                 return ERR_PTR(-EINVAL);
1682
1683         if (dev_out->flags & IFF_LOOPBACK)
1684                 flags |= RTCF_LOCAL;
1685
1686         if (type == RTN_BROADCAST) {
1687                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
1688                 fi = NULL;
1689         } else if (type == RTN_MULTICAST) {
1690                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
1691                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
1692                                      fl4->flowi4_proto))
1693                         flags &= ~RTCF_LOCAL;
1694                 /* If multicast route do not exist use
1695                  * default one, but do not gateway in this case.
1696                  * Yes, it is hack.
1697                  */
1698                 if (fi && res->prefixlen < 4)
1699                         fi = NULL;
1700         }
1701
1702         rth = rt_dst_alloc(dev_out,
1703                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1704                            IN_DEV_CONF_GET(in_dev, NOXFRM));
1705         if (!rth)
1706                 return ERR_PTR(-ENOBUFS);
1707
1708         rth->dst.output = ip_output;
1709
1710         rth->rt_genid = rt_genid(dev_net(dev_out));
1711         rth->rt_flags   = flags;
1712         rth->rt_type    = type;
1713         rth->rt_dst     = fl4->daddr;
1714         rth->rt_route_iif = 0;
1715         rth->rt_iif     = orig_oif ? : dev_out->ifindex;
1716         rth->rt_oif     = orig_oif;
1717         rth->rt_mark    = fl4->flowi4_mark;
1718         rth->rt_pmtu    = 0;
1719         rth->rt_gateway = fl4->daddr;
1720         rth->fi = NULL;
1721
1722         RT_CACHE_STAT_INC(out_slow_tot);
1723
1724         if (flags & RTCF_LOCAL)
1725                 rth->dst.input = ip_local_deliver;
1726         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1727                 if (flags & RTCF_LOCAL &&
1728                     !(dev_out->flags & IFF_LOOPBACK)) {
1729                         rth->dst.output = ip_mc_output;
1730                         RT_CACHE_STAT_INC(out_slow_mc);
1731                 }
1732 #ifdef CONFIG_IP_MROUTE
1733                 if (type == RTN_MULTICAST) {
1734                         if (IN_DEV_MFORWARD(in_dev) &&
1735                             !ipv4_is_local_multicast(fl4->daddr)) {
1736                                 rth->dst.input = ip_mr_input;
1737                                 rth->dst.output = ip_mc_output;
1738                         }
1739                 }
1740 #endif
1741         }
1742
1743         rt_set_nexthop(rth, fl4, res, fi, type, 0);
1744
1745         if (fl4->flowi4_flags & FLOWI_FLAG_RT_NOCACHE)
1746                 rth->dst.flags |= DST_NOCACHE;
1747
1748         return rth;
1749 }
1750
1751 /*
1752  * Major route resolver routine.
1753  */
1754
1755 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
1756 {
1757         struct net_device *dev_out = NULL;
1758         __u8 tos = RT_FL_TOS(fl4);
1759         unsigned int flags = 0;
1760         struct fib_result res;
1761         struct rtable *rth;
1762         int orig_oif;
1763
1764         res.tclassid    = 0;
1765         res.fi          = NULL;
1766         res.table       = NULL;
1767
1768         orig_oif = fl4->flowi4_oif;
1769
1770         fl4->flowi4_iif = net->loopback_dev->ifindex;
1771         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
1772         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
1773                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
1774
1775         rcu_read_lock();
1776         if (fl4->saddr) {
1777                 rth = ERR_PTR(-EINVAL);
1778                 if (ipv4_is_multicast(fl4->saddr) ||
1779                     ipv4_is_lbcast(fl4->saddr) ||
1780                     ipv4_is_zeronet(fl4->saddr))
1781                         goto out;
1782
1783                 /* I removed check for oif == dev_out->oif here.
1784                    It was wrong for two reasons:
1785                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
1786                       is assigned to multiple interfaces.
1787                    2. Moreover, we are allowed to send packets with saddr
1788                       of another iface. --ANK
1789                  */
1790
1791                 if (fl4->flowi4_oif == 0 &&
1792                     (ipv4_is_multicast(fl4->daddr) ||
1793                      ipv4_is_lbcast(fl4->daddr))) {
1794                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1795                         dev_out = __ip_dev_find(net, fl4->saddr, false);
1796                         if (dev_out == NULL)
1797                                 goto out;
1798
1799                         /* Special hack: user can direct multicasts
1800                            and limited broadcast via necessary interface
1801                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
1802                            This hack is not just for fun, it allows
1803                            vic,vat and friends to work.
1804                            They bind socket to loopback, set ttl to zero
1805                            and expect that it will work.
1806                            From the viewpoint of routing cache they are broken,
1807                            because we are not allowed to build multicast path
1808                            with loopback source addr (look, routing cache
1809                            cannot know, that ttl is zero, so that packet
1810                            will not leave this host and route is valid).
1811                            Luckily, this hack is good workaround.
1812                          */
1813
1814                         fl4->flowi4_oif = dev_out->ifindex;
1815                         goto make_route;
1816                 }
1817
1818                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
1819                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1820                         if (!__ip_dev_find(net, fl4->saddr, false))
1821                                 goto out;
1822                 }
1823         }
1824
1825
1826         if (fl4->flowi4_oif) {
1827                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
1828                 rth = ERR_PTR(-ENODEV);
1829                 if (dev_out == NULL)
1830                         goto out;
1831
1832                 /* RACE: Check return value of inet_select_addr instead. */
1833                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
1834                         rth = ERR_PTR(-ENETUNREACH);
1835                         goto out;
1836                 }
1837                 if (ipv4_is_local_multicast(fl4->daddr) ||
1838                     ipv4_is_lbcast(fl4->daddr)) {
1839                         if (!fl4->saddr)
1840                                 fl4->saddr = inet_select_addr(dev_out, 0,
1841                                                               RT_SCOPE_LINK);
1842                         goto make_route;
1843                 }
1844                 if (fl4->saddr) {
1845                         if (ipv4_is_multicast(fl4->daddr))
1846                                 fl4->saddr = inet_select_addr(dev_out, 0,
1847                                                               fl4->flowi4_scope);
1848                         else if (!fl4->daddr)
1849                                 fl4->saddr = inet_select_addr(dev_out, 0,
1850                                                               RT_SCOPE_HOST);
1851                 }
1852         }
1853
1854         if (!fl4->daddr) {
1855                 fl4->daddr = fl4->saddr;
1856                 if (!fl4->daddr)
1857                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
1858                 dev_out = net->loopback_dev;
1859                 fl4->flowi4_oif = net->loopback_dev->ifindex;
1860                 res.type = RTN_LOCAL;
1861                 flags |= RTCF_LOCAL;
1862                 goto make_route;
1863         }
1864
1865         if (fib_lookup(net, fl4, &res)) {
1866                 res.fi = NULL;
1867                 res.table = NULL;
1868                 if (fl4->flowi4_oif) {
1869                         /* Apparently, routing tables are wrong. Assume,
1870                            that the destination is on link.
1871
1872                            WHY? DW.
1873                            Because we are allowed to send to iface
1874                            even if it has NO routes and NO assigned
1875                            addresses. When oif is specified, routing
1876                            tables are looked up with only one purpose:
1877                            to catch if destination is gatewayed, rather than
1878                            direct. Moreover, if MSG_DONTROUTE is set,
1879                            we send packet, ignoring both routing tables
1880                            and ifaddr state. --ANK
1881
1882
1883                            We could make it even if oif is unknown,
1884                            likely IPv6, but we do not.
1885                          */
1886
1887                         if (fl4->saddr == 0)
1888                                 fl4->saddr = inet_select_addr(dev_out, 0,
1889                                                               RT_SCOPE_LINK);
1890                         res.type = RTN_UNICAST;
1891                         goto make_route;
1892                 }
1893                 rth = ERR_PTR(-ENETUNREACH);
1894                 goto out;
1895         }
1896
1897         if (res.type == RTN_LOCAL) {
1898                 if (!fl4->saddr) {
1899                         if (res.fi->fib_prefsrc)
1900                                 fl4->saddr = res.fi->fib_prefsrc;
1901                         else
1902                                 fl4->saddr = fl4->daddr;
1903                 }
1904                 dev_out = net->loopback_dev;
1905                 fl4->flowi4_oif = dev_out->ifindex;
1906                 res.fi = NULL;
1907                 flags |= RTCF_LOCAL;
1908                 goto make_route;
1909         }
1910
1911 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1912         if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
1913                 fib_select_multipath(&res);
1914         else
1915 #endif
1916         if (!res.prefixlen &&
1917             res.table->tb_num_default > 1 &&
1918             res.type == RTN_UNICAST && !fl4->flowi4_oif)
1919                 fib_select_default(&res);
1920
1921         if (!fl4->saddr)
1922                 fl4->saddr = FIB_RES_PREFSRC(net, res);
1923
1924         dev_out = FIB_RES_DEV(res);
1925         fl4->flowi4_oif = dev_out->ifindex;
1926
1927
1928 make_route:
1929         rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
1930
1931 out:
1932         rcu_read_unlock();
1933         return rth;
1934 }
1935 EXPORT_SYMBOL_GPL(__ip_route_output_key);
1936
1937 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
1938 {
1939         return NULL;
1940 }
1941
1942 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
1943 {
1944         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1945
1946         return mtu ? : dst->dev->mtu;
1947 }
1948
1949 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
1950                                           struct sk_buff *skb, u32 mtu)
1951 {
1952 }
1953
1954 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
1955                                        struct sk_buff *skb)
1956 {
1957 }
1958
1959 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
1960                                           unsigned long old)
1961 {
1962         return NULL;
1963 }
1964
1965 static struct dst_ops ipv4_dst_blackhole_ops = {
1966         .family                 =       AF_INET,
1967         .protocol               =       cpu_to_be16(ETH_P_IP),
1968         .destroy                =       ipv4_dst_destroy,
1969         .check                  =       ipv4_blackhole_dst_check,
1970         .mtu                    =       ipv4_blackhole_mtu,
1971         .default_advmss         =       ipv4_default_advmss,
1972         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
1973         .redirect               =       ipv4_rt_blackhole_redirect,
1974         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
1975         .neigh_lookup           =       ipv4_neigh_lookup,
1976 };
1977
1978 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
1979 {
1980         struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
1981         struct rtable *ort = (struct rtable *) dst_orig;
1982
1983         if (rt) {
1984                 struct dst_entry *new = &rt->dst;
1985
1986                 new->__use = 1;
1987                 new->input = dst_discard;
1988                 new->output = dst_discard;
1989
1990                 new->dev = ort->dst.dev;
1991                 if (new->dev)
1992                         dev_hold(new->dev);
1993
1994                 rt->rt_route_iif = ort->rt_route_iif;
1995                 rt->rt_iif = ort->rt_iif;
1996                 rt->rt_oif = ort->rt_oif;
1997                 rt->rt_mark = ort->rt_mark;
1998                 rt->rt_pmtu = ort->rt_pmtu;
1999
2000                 rt->rt_genid = rt_genid(net);
2001                 rt->rt_flags = ort->rt_flags;
2002                 rt->rt_type = ort->rt_type;
2003                 rt->rt_dst = ort->rt_dst;
2004                 rt->rt_gateway = ort->rt_gateway;
2005                 rt->fi = ort->fi;
2006                 if (rt->fi)
2007                         atomic_inc(&rt->fi->fib_clntref);
2008
2009                 dst_free(new);
2010         }
2011
2012         dst_release(dst_orig);
2013
2014         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2015 }
2016
2017 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2018                                     struct sock *sk)
2019 {
2020         struct rtable *rt = __ip_route_output_key(net, flp4);
2021
2022         if (IS_ERR(rt))
2023                 return rt;
2024
2025         if (flp4->flowi4_proto)
2026                 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2027                                                    flowi4_to_flowi(flp4),
2028                                                    sk, 0);
2029
2030         return rt;
2031 }
2032 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2033
2034 static int rt_fill_info(struct net *net,  __be32 src, struct flowi4 *fl4,
2035                         struct sk_buff *skb, u32 pid, u32 seq, int event,
2036                         int nowait, unsigned int flags)
2037 {
2038         struct rtable *rt = skb_rtable(skb);
2039         struct rtmsg *r;
2040         struct nlmsghdr *nlh;
2041         unsigned long expires = 0;
2042         u32 error;
2043         u32 metrics[RTAX_MAX];
2044
2045         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2046         if (nlh == NULL)
2047                 return -EMSGSIZE;
2048
2049         r = nlmsg_data(nlh);
2050         r->rtm_family    = AF_INET;
2051         r->rtm_dst_len  = 32;
2052         r->rtm_src_len  = 0;
2053         r->rtm_tos      = fl4->flowi4_tos;
2054         r->rtm_table    = RT_TABLE_MAIN;
2055         if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2056                 goto nla_put_failure;
2057         r->rtm_type     = rt->rt_type;
2058         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2059         r->rtm_protocol = RTPROT_UNSPEC;
2060         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2061         if (rt->rt_flags & RTCF_NOTIFY)
2062                 r->rtm_flags |= RTM_F_NOTIFY;
2063
2064         if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2065                 goto nla_put_failure;
2066         if (src) {
2067                 r->rtm_src_len = 32;
2068                 if (nla_put_be32(skb, RTA_SRC, src))
2069                         goto nla_put_failure;
2070         }
2071         if (rt->dst.dev &&
2072             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2073                 goto nla_put_failure;
2074 #ifdef CONFIG_IP_ROUTE_CLASSID
2075         if (rt->dst.tclassid &&
2076             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2077                 goto nla_put_failure;
2078 #endif
2079         if (!rt_is_input_route(rt) &&
2080             fl4->saddr != src) {
2081                 if (nla_put_be32(skb, RTA_PREFSRC, fl4->saddr))
2082                         goto nla_put_failure;
2083         }
2084         if (fl4->daddr != rt->rt_gateway &&
2085             nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2086                 goto nla_put_failure;
2087
2088         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2089         if (rt->rt_pmtu)
2090                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2091         if (rtnetlink_put_metrics(skb, metrics) < 0)
2092                 goto nla_put_failure;
2093
2094         if (rt->rt_mark &&
2095             nla_put_be32(skb, RTA_MARK, rt->rt_mark))
2096                 goto nla_put_failure;
2097
2098         error = rt->dst.error;
2099         expires = rt->dst.expires;
2100         if (expires) {
2101                 if (time_before(jiffies, expires))
2102                         expires -= jiffies;
2103                 else
2104                         expires = 0;
2105         }
2106
2107         if (rt_is_input_route(rt)) {
2108 #ifdef CONFIG_IP_MROUTE
2109                 __be32 dst = rt->rt_dst;
2110
2111                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2112                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2113                         int err = ipmr_get_route(net, skb,
2114                                                  fl4->saddr, fl4->daddr,
2115                                                  r, nowait);
2116                         if (err <= 0) {
2117                                 if (!nowait) {
2118                                         if (err == 0)
2119                                                 return 0;
2120                                         goto nla_put_failure;
2121                                 } else {
2122                                         if (err == -EMSGSIZE)
2123                                                 goto nla_put_failure;
2124                                         error = err;
2125                                 }
2126                         }
2127                 } else
2128 #endif
2129                         if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
2130                                 goto nla_put_failure;
2131         }
2132
2133         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2134                 goto nla_put_failure;
2135
2136         return nlmsg_end(skb, nlh);
2137
2138 nla_put_failure:
2139         nlmsg_cancel(skb, nlh);
2140         return -EMSGSIZE;
2141 }
2142
2143 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
2144 {
2145         struct net *net = sock_net(in_skb->sk);
2146         struct rtmsg *rtm;
2147         struct nlattr *tb[RTA_MAX+1];
2148         struct rtable *rt = NULL;
2149         struct flowi4 fl4;
2150         __be32 dst = 0;
2151         __be32 src = 0;
2152         u32 iif;
2153         int err;
2154         int mark;
2155         struct sk_buff *skb;
2156
2157         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2158         if (err < 0)
2159                 goto errout;
2160
2161         rtm = nlmsg_data(nlh);
2162
2163         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2164         if (skb == NULL) {
2165                 err = -ENOBUFS;
2166                 goto errout;
2167         }
2168
2169         /* Reserve room for dummy headers, this skb can pass
2170            through good chunk of routing engine.
2171          */
2172         skb_reset_mac_header(skb);
2173         skb_reset_network_header(skb);
2174
2175         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2176         ip_hdr(skb)->protocol = IPPROTO_ICMP;
2177         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2178
2179         src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2180         dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2181         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2182         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2183
2184         memset(&fl4, 0, sizeof(fl4));
2185         fl4.daddr = dst;
2186         fl4.saddr = src;
2187         fl4.flowi4_tos = rtm->rtm_tos;
2188         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2189         fl4.flowi4_mark = mark;
2190
2191         if (iif) {
2192                 struct net_device *dev;
2193
2194                 dev = __dev_get_by_index(net, iif);
2195                 if (dev == NULL) {
2196                         err = -ENODEV;
2197                         goto errout_free;
2198                 }
2199
2200                 skb->protocol   = htons(ETH_P_IP);
2201                 skb->dev        = dev;
2202                 skb->mark       = mark;
2203                 local_bh_disable();
2204                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2205                 local_bh_enable();
2206
2207                 rt = skb_rtable(skb);
2208                 if (err == 0 && rt->dst.error)
2209                         err = -rt->dst.error;
2210         } else {
2211                 rt = ip_route_output_key(net, &fl4);
2212
2213                 err = 0;
2214                 if (IS_ERR(rt))
2215                         err = PTR_ERR(rt);
2216         }
2217
2218         if (err)
2219                 goto errout_free;
2220
2221         skb_dst_set(skb, &rt->dst);
2222         if (rtm->rtm_flags & RTM_F_NOTIFY)
2223                 rt->rt_flags |= RTCF_NOTIFY;
2224
2225         err = rt_fill_info(net, src, &fl4, skb,
2226                            NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2227                            RTM_NEWROUTE, 0, 0);
2228         if (err <= 0)
2229                 goto errout_free;
2230
2231         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2232 errout:
2233         return err;
2234
2235 errout_free:
2236         kfree_skb(skb);
2237         goto errout;
2238 }
2239
2240 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
2241 {
2242         return skb->len;
2243 }
2244
2245 void ip_rt_multicast_event(struct in_device *in_dev)
2246 {
2247         rt_cache_flush(dev_net(in_dev->dev), 0);
2248 }
2249
2250 #ifdef CONFIG_SYSCTL
2251 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
2252                                         void __user *buffer,
2253                                         size_t *lenp, loff_t *ppos)
2254 {
2255         if (write) {
2256                 int flush_delay;
2257                 ctl_table ctl;
2258                 struct net *net;
2259
2260                 memcpy(&ctl, __ctl, sizeof(ctl));
2261                 ctl.data = &flush_delay;
2262                 proc_dointvec(&ctl, write, buffer, lenp, ppos);
2263
2264                 net = (struct net *)__ctl->extra1;
2265                 rt_cache_flush(net, flush_delay);
2266                 return 0;
2267         }
2268
2269         return -EINVAL;
2270 }
2271
2272 static ctl_table ipv4_route_table[] = {
2273         {
2274                 .procname       = "gc_thresh",
2275                 .data           = &ipv4_dst_ops.gc_thresh,
2276                 .maxlen         = sizeof(int),
2277                 .mode           = 0644,
2278                 .proc_handler   = proc_dointvec,
2279         },
2280         {
2281                 .procname       = "max_size",
2282                 .data           = &ip_rt_max_size,
2283                 .maxlen         = sizeof(int),
2284                 .mode           = 0644,
2285                 .proc_handler   = proc_dointvec,
2286         },
2287         {
2288                 /*  Deprecated. Use gc_min_interval_ms */
2289
2290                 .procname       = "gc_min_interval",
2291                 .data           = &ip_rt_gc_min_interval,
2292                 .maxlen         = sizeof(int),
2293                 .mode           = 0644,
2294                 .proc_handler   = proc_dointvec_jiffies,
2295         },
2296         {
2297                 .procname       = "gc_min_interval_ms",
2298                 .data           = &ip_rt_gc_min_interval,
2299                 .maxlen         = sizeof(int),
2300                 .mode           = 0644,
2301                 .proc_handler   = proc_dointvec_ms_jiffies,
2302         },
2303         {
2304                 .procname       = "gc_timeout",
2305                 .data           = &ip_rt_gc_timeout,
2306                 .maxlen         = sizeof(int),
2307                 .mode           = 0644,
2308                 .proc_handler   = proc_dointvec_jiffies,
2309         },
2310         {
2311                 .procname       = "gc_interval",
2312                 .data           = &ip_rt_gc_interval,
2313                 .maxlen         = sizeof(int),
2314                 .mode           = 0644,
2315                 .proc_handler   = proc_dointvec_jiffies,
2316         },
2317         {
2318                 .procname       = "redirect_load",
2319                 .data           = &ip_rt_redirect_load,
2320                 .maxlen         = sizeof(int),
2321                 .mode           = 0644,
2322                 .proc_handler   = proc_dointvec,
2323         },
2324         {
2325                 .procname       = "redirect_number",
2326                 .data           = &ip_rt_redirect_number,
2327                 .maxlen         = sizeof(int),
2328                 .mode           = 0644,
2329                 .proc_handler   = proc_dointvec,
2330         },
2331         {
2332                 .procname       = "redirect_silence",
2333                 .data           = &ip_rt_redirect_silence,
2334                 .maxlen         = sizeof(int),
2335                 .mode           = 0644,
2336                 .proc_handler   = proc_dointvec,
2337         },
2338         {
2339                 .procname       = "error_cost",
2340                 .data           = &ip_rt_error_cost,
2341                 .maxlen         = sizeof(int),
2342                 .mode           = 0644,
2343                 .proc_handler   = proc_dointvec,
2344         },
2345         {
2346                 .procname       = "error_burst",
2347                 .data           = &ip_rt_error_burst,
2348                 .maxlen         = sizeof(int),
2349                 .mode           = 0644,
2350                 .proc_handler   = proc_dointvec,
2351         },
2352         {
2353                 .procname       = "gc_elasticity",
2354                 .data           = &ip_rt_gc_elasticity,
2355                 .maxlen         = sizeof(int),
2356                 .mode           = 0644,
2357                 .proc_handler   = proc_dointvec,
2358         },
2359         {
2360                 .procname       = "mtu_expires",
2361                 .data           = &ip_rt_mtu_expires,
2362                 .maxlen         = sizeof(int),
2363                 .mode           = 0644,
2364                 .proc_handler   = proc_dointvec_jiffies,
2365         },
2366         {
2367                 .procname       = "min_pmtu",
2368                 .data           = &ip_rt_min_pmtu,
2369                 .maxlen         = sizeof(int),
2370                 .mode           = 0644,
2371                 .proc_handler   = proc_dointvec,
2372         },
2373         {
2374                 .procname       = "min_adv_mss",
2375                 .data           = &ip_rt_min_advmss,
2376                 .maxlen         = sizeof(int),
2377                 .mode           = 0644,
2378                 .proc_handler   = proc_dointvec,
2379         },
2380         { }
2381 };
2382
2383 static struct ctl_table ipv4_route_flush_table[] = {
2384         {
2385                 .procname       = "flush",
2386                 .maxlen         = sizeof(int),
2387                 .mode           = 0200,
2388                 .proc_handler   = ipv4_sysctl_rtcache_flush,
2389         },
2390         { },
2391 };
2392
2393 static __net_init int sysctl_route_net_init(struct net *net)
2394 {
2395         struct ctl_table *tbl;
2396
2397         tbl = ipv4_route_flush_table;
2398         if (!net_eq(net, &init_net)) {
2399                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2400                 if (tbl == NULL)
2401                         goto err_dup;
2402         }
2403         tbl[0].extra1 = net;
2404
2405         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2406         if (net->ipv4.route_hdr == NULL)
2407                 goto err_reg;
2408         return 0;
2409
2410 err_reg:
2411         if (tbl != ipv4_route_flush_table)
2412                 kfree(tbl);
2413 err_dup:
2414         return -ENOMEM;
2415 }
2416
2417 static __net_exit void sysctl_route_net_exit(struct net *net)
2418 {
2419         struct ctl_table *tbl;
2420
2421         tbl = net->ipv4.route_hdr->ctl_table_arg;
2422         unregister_net_sysctl_table(net->ipv4.route_hdr);
2423         BUG_ON(tbl == ipv4_route_flush_table);
2424         kfree(tbl);
2425 }
2426
2427 static __net_initdata struct pernet_operations sysctl_route_ops = {
2428         .init = sysctl_route_net_init,
2429         .exit = sysctl_route_net_exit,
2430 };
2431 #endif
2432
2433 static __net_init int rt_genid_init(struct net *net)
2434 {
2435         get_random_bytes(&net->ipv4.rt_genid,
2436                          sizeof(net->ipv4.rt_genid));
2437         get_random_bytes(&net->ipv4.dev_addr_genid,
2438                          sizeof(net->ipv4.dev_addr_genid));
2439         return 0;
2440 }
2441
2442 static __net_initdata struct pernet_operations rt_genid_ops = {
2443         .init = rt_genid_init,
2444 };
2445
2446 static int __net_init ipv4_inetpeer_init(struct net *net)
2447 {
2448         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2449
2450         if (!bp)
2451                 return -ENOMEM;
2452         inet_peer_base_init(bp);
2453         net->ipv4.peers = bp;
2454         return 0;
2455 }
2456
2457 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2458 {
2459         struct inet_peer_base *bp = net->ipv4.peers;
2460
2461         net->ipv4.peers = NULL;
2462         inetpeer_invalidate_tree(bp);
2463         kfree(bp);
2464 }
2465
2466 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2467         .init   =       ipv4_inetpeer_init,
2468         .exit   =       ipv4_inetpeer_exit,
2469 };
2470
2471 #ifdef CONFIG_IP_ROUTE_CLASSID
2472 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2473 #endif /* CONFIG_IP_ROUTE_CLASSID */
2474
2475 int __init ip_rt_init(void)
2476 {
2477         int rc = 0;
2478
2479 #ifdef CONFIG_IP_ROUTE_CLASSID
2480         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2481         if (!ip_rt_acct)
2482                 panic("IP: failed to allocate ip_rt_acct\n");
2483 #endif
2484
2485         ipv4_dst_ops.kmem_cachep =
2486                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2487                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2488
2489         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2490
2491         if (dst_entries_init(&ipv4_dst_ops) < 0)
2492                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2493
2494         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2495                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2496
2497         ipv4_dst_ops.gc_thresh = ~0;
2498         ip_rt_max_size = INT_MAX;
2499
2500         devinet_init();
2501         ip_fib_init();
2502
2503         if (ip_rt_proc_init())
2504                 pr_err("Unable to create route proc files\n");
2505 #ifdef CONFIG_XFRM
2506         xfrm_init();
2507         xfrm4_init(ip_rt_max_size);
2508 #endif
2509         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2510
2511 #ifdef CONFIG_SYSCTL
2512         register_pernet_subsys(&sysctl_route_ops);
2513 #endif
2514         register_pernet_subsys(&rt_genid_ops);
2515         register_pernet_subsys(&ipv4_inetpeer_ops);
2516         return rc;
2517 }
2518
2519 #ifdef CONFIG_SYSCTL
2520 /*
2521  * We really need to sanitize the damn ipv4 init order, then all
2522  * this nonsense will go away.
2523  */
2524 void __init ip_static_sysctl_init(void)
2525 {
2526         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2527 }
2528 #endif