ipv4: Remove extraneous assignment of dst->tclassid.
[linux-3.10.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 static int rt_chain_length_max __read_mostly    = 20;
137
138 static struct delayed_work expires_work;
139 static unsigned long expires_ljiffies;
140
141 /*
142  *      Interface to generic destination cache.
143  */
144
145 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
146 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
147 static unsigned int      ipv4_mtu(const struct dst_entry *dst);
148 static void              ipv4_dst_destroy(struct dst_entry *dst);
149 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
150 static void              ipv4_link_failure(struct sk_buff *skb);
151 static void              ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
152 static int rt_garbage_collect(struct dst_ops *ops);
153
154 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
155                             int how)
156 {
157 }
158
159 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
160 {
161         struct rtable *rt = (struct rtable *) dst;
162         struct inet_peer *peer;
163         u32 *p = NULL;
164
165         peer = rt_get_peer_create(rt, rt->rt_dst);
166         if (peer) {
167                 u32 *old_p = __DST_METRICS_PTR(old);
168                 unsigned long prev, new;
169
170                 p = peer->metrics;
171                 if (inet_metrics_new(peer))
172                         memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
173
174                 new = (unsigned long) p;
175                 prev = cmpxchg(&dst->_metrics, old, new);
176
177                 if (prev != old) {
178                         p = __DST_METRICS_PTR(prev);
179                         if (prev & DST_METRICS_READ_ONLY)
180                                 p = NULL;
181                 } else {
182                         if (rt->fi) {
183                                 fib_info_put(rt->fi);
184                                 rt->fi = NULL;
185                         }
186                 }
187         }
188         return p;
189 }
190
191 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr);
192
193 static struct dst_ops ipv4_dst_ops = {
194         .family =               AF_INET,
195         .protocol =             cpu_to_be16(ETH_P_IP),
196         .gc =                   rt_garbage_collect,
197         .check =                ipv4_dst_check,
198         .default_advmss =       ipv4_default_advmss,
199         .mtu =                  ipv4_mtu,
200         .cow_metrics =          ipv4_cow_metrics,
201         .destroy =              ipv4_dst_destroy,
202         .ifdown =               ipv4_dst_ifdown,
203         .negative_advice =      ipv4_negative_advice,
204         .link_failure =         ipv4_link_failure,
205         .update_pmtu =          ip_rt_update_pmtu,
206         .local_out =            __ip_local_out,
207         .neigh_lookup =         ipv4_neigh_lookup,
208 };
209
210 #define ECN_OR_COST(class)      TC_PRIO_##class
211
212 const __u8 ip_tos2prio[16] = {
213         TC_PRIO_BESTEFFORT,
214         ECN_OR_COST(BESTEFFORT),
215         TC_PRIO_BESTEFFORT,
216         ECN_OR_COST(BESTEFFORT),
217         TC_PRIO_BULK,
218         ECN_OR_COST(BULK),
219         TC_PRIO_BULK,
220         ECN_OR_COST(BULK),
221         TC_PRIO_INTERACTIVE,
222         ECN_OR_COST(INTERACTIVE),
223         TC_PRIO_INTERACTIVE,
224         ECN_OR_COST(INTERACTIVE),
225         TC_PRIO_INTERACTIVE_BULK,
226         ECN_OR_COST(INTERACTIVE_BULK),
227         TC_PRIO_INTERACTIVE_BULK,
228         ECN_OR_COST(INTERACTIVE_BULK)
229 };
230 EXPORT_SYMBOL(ip_tos2prio);
231
232 /*
233  * Route cache.
234  */
235
236 /* The locking scheme is rather straight forward:
237  *
238  * 1) Read-Copy Update protects the buckets of the central route hash.
239  * 2) Only writers remove entries, and they hold the lock
240  *    as they look at rtable reference counts.
241  * 3) Only readers acquire references to rtable entries,
242  *    they do so with atomic increments and with the
243  *    lock held.
244  */
245
246 struct rt_hash_bucket {
247         struct rtable __rcu     *chain;
248 };
249
250 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
251         defined(CONFIG_PROVE_LOCKING)
252 /*
253  * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
254  * The size of this table is a power of two and depends on the number of CPUS.
255  * (on lockdep we have a quite big spinlock_t, so keep the size down there)
256  */
257 #ifdef CONFIG_LOCKDEP
258 # define RT_HASH_LOCK_SZ        256
259 #else
260 # if NR_CPUS >= 32
261 #  define RT_HASH_LOCK_SZ       4096
262 # elif NR_CPUS >= 16
263 #  define RT_HASH_LOCK_SZ       2048
264 # elif NR_CPUS >= 8
265 #  define RT_HASH_LOCK_SZ       1024
266 # elif NR_CPUS >= 4
267 #  define RT_HASH_LOCK_SZ       512
268 # else
269 #  define RT_HASH_LOCK_SZ       256
270 # endif
271 #endif
272
273 static spinlock_t       *rt_hash_locks;
274 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
275
276 static __init void rt_hash_lock_init(void)
277 {
278         int i;
279
280         rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
281                         GFP_KERNEL);
282         if (!rt_hash_locks)
283                 panic("IP: failed to allocate rt_hash_locks\n");
284
285         for (i = 0; i < RT_HASH_LOCK_SZ; i++)
286                 spin_lock_init(&rt_hash_locks[i]);
287 }
288 #else
289 # define rt_hash_lock_addr(slot) NULL
290
291 static inline void rt_hash_lock_init(void)
292 {
293 }
294 #endif
295
296 static struct rt_hash_bucket    *rt_hash_table __read_mostly;
297 static unsigned int             rt_hash_mask __read_mostly;
298 static unsigned int             rt_hash_log  __read_mostly;
299
300 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
301 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
302
303 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
304                                    int genid)
305 {
306         return jhash_3words((__force u32)daddr, (__force u32)saddr,
307                             idx, genid)
308                 & rt_hash_mask;
309 }
310
311 static inline int rt_genid(struct net *net)
312 {
313         return atomic_read(&net->ipv4.rt_genid);
314 }
315
316 #ifdef CONFIG_PROC_FS
317 struct rt_cache_iter_state {
318         struct seq_net_private p;
319         int bucket;
320         int genid;
321 };
322
323 static struct rtable *rt_cache_get_first(struct seq_file *seq)
324 {
325         struct rt_cache_iter_state *st = seq->private;
326         struct rtable *r = NULL;
327
328         for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
329                 if (!rcu_access_pointer(rt_hash_table[st->bucket].chain))
330                         continue;
331                 rcu_read_lock_bh();
332                 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
333                 while (r) {
334                         if (dev_net(r->dst.dev) == seq_file_net(seq) &&
335                             r->rt_genid == st->genid)
336                                 return r;
337                         r = rcu_dereference_bh(r->dst.rt_next);
338                 }
339                 rcu_read_unlock_bh();
340         }
341         return r;
342 }
343
344 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
345                                           struct rtable *r)
346 {
347         struct rt_cache_iter_state *st = seq->private;
348
349         r = rcu_dereference_bh(r->dst.rt_next);
350         while (!r) {
351                 rcu_read_unlock_bh();
352                 do {
353                         if (--st->bucket < 0)
354                                 return NULL;
355                 } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain));
356                 rcu_read_lock_bh();
357                 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
358         }
359         return r;
360 }
361
362 static struct rtable *rt_cache_get_next(struct seq_file *seq,
363                                         struct rtable *r)
364 {
365         struct rt_cache_iter_state *st = seq->private;
366         while ((r = __rt_cache_get_next(seq, r)) != NULL) {
367                 if (dev_net(r->dst.dev) != seq_file_net(seq))
368                         continue;
369                 if (r->rt_genid == st->genid)
370                         break;
371         }
372         return r;
373 }
374
375 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
376 {
377         struct rtable *r = rt_cache_get_first(seq);
378
379         if (r)
380                 while (pos && (r = rt_cache_get_next(seq, r)))
381                         --pos;
382         return pos ? NULL : r;
383 }
384
385 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
386 {
387         struct rt_cache_iter_state *st = seq->private;
388         if (*pos)
389                 return rt_cache_get_idx(seq, *pos - 1);
390         st->genid = rt_genid(seq_file_net(seq));
391         return SEQ_START_TOKEN;
392 }
393
394 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
395 {
396         struct rtable *r;
397
398         if (v == SEQ_START_TOKEN)
399                 r = rt_cache_get_first(seq);
400         else
401                 r = rt_cache_get_next(seq, v);
402         ++*pos;
403         return r;
404 }
405
406 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
407 {
408         if (v && v != SEQ_START_TOKEN)
409                 rcu_read_unlock_bh();
410 }
411
412 static int rt_cache_seq_show(struct seq_file *seq, void *v)
413 {
414         if (v == SEQ_START_TOKEN)
415                 seq_printf(seq, "%-127s\n",
416                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
417                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
418                            "HHUptod\tSpecDst");
419         else {
420                 struct rtable *r = v;
421                 struct neighbour *n;
422                 int len, HHUptod;
423
424                 rcu_read_lock();
425                 n = dst_get_neighbour_noref(&r->dst);
426                 HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0;
427                 rcu_read_unlock();
428
429                 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
430                               "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
431                         r->dst.dev ? r->dst.dev->name : "*",
432                         (__force u32)r->rt_dst,
433                         (__force u32)r->rt_gateway,
434                         r->rt_flags, atomic_read(&r->dst.__refcnt),
435                         r->dst.__use, 0, (__force u32)r->rt_src,
436                         dst_metric_advmss(&r->dst) + 40,
437                         dst_metric(&r->dst, RTAX_WINDOW),
438                         (int)((dst_metric(&r->dst, RTAX_RTT) >> 3) +
439                               dst_metric(&r->dst, RTAX_RTTVAR)),
440                         r->rt_key_tos,
441                         -1,
442                         HHUptod,
443                         0, &len);
444
445                 seq_printf(seq, "%*s\n", 127 - len, "");
446         }
447         return 0;
448 }
449
450 static const struct seq_operations rt_cache_seq_ops = {
451         .start  = rt_cache_seq_start,
452         .next   = rt_cache_seq_next,
453         .stop   = rt_cache_seq_stop,
454         .show   = rt_cache_seq_show,
455 };
456
457 static int rt_cache_seq_open(struct inode *inode, struct file *file)
458 {
459         return seq_open_net(inode, file, &rt_cache_seq_ops,
460                         sizeof(struct rt_cache_iter_state));
461 }
462
463 static const struct file_operations rt_cache_seq_fops = {
464         .owner   = THIS_MODULE,
465         .open    = rt_cache_seq_open,
466         .read    = seq_read,
467         .llseek  = seq_lseek,
468         .release = seq_release_net,
469 };
470
471
472 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
473 {
474         int cpu;
475
476         if (*pos == 0)
477                 return SEQ_START_TOKEN;
478
479         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
480                 if (!cpu_possible(cpu))
481                         continue;
482                 *pos = cpu+1;
483                 return &per_cpu(rt_cache_stat, cpu);
484         }
485         return NULL;
486 }
487
488 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
489 {
490         int cpu;
491
492         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
493                 if (!cpu_possible(cpu))
494                         continue;
495                 *pos = cpu+1;
496                 return &per_cpu(rt_cache_stat, cpu);
497         }
498         return NULL;
499
500 }
501
502 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
503 {
504
505 }
506
507 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
508 {
509         struct rt_cache_stat *st = v;
510
511         if (v == SEQ_START_TOKEN) {
512                 seq_printf(seq, "entries  in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src  out_hit out_slow_tot out_slow_mc  gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
513                 return 0;
514         }
515
516         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
517                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
518                    dst_entries_get_slow(&ipv4_dst_ops),
519                    st->in_hit,
520                    st->in_slow_tot,
521                    st->in_slow_mc,
522                    st->in_no_route,
523                    st->in_brd,
524                    st->in_martian_dst,
525                    st->in_martian_src,
526
527                    st->out_hit,
528                    st->out_slow_tot,
529                    st->out_slow_mc,
530
531                    st->gc_total,
532                    st->gc_ignored,
533                    st->gc_goal_miss,
534                    st->gc_dst_overflow,
535                    st->in_hlist_search,
536                    st->out_hlist_search
537                 );
538         return 0;
539 }
540
541 static const struct seq_operations rt_cpu_seq_ops = {
542         .start  = rt_cpu_seq_start,
543         .next   = rt_cpu_seq_next,
544         .stop   = rt_cpu_seq_stop,
545         .show   = rt_cpu_seq_show,
546 };
547
548
549 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
550 {
551         return seq_open(file, &rt_cpu_seq_ops);
552 }
553
554 static const struct file_operations rt_cpu_seq_fops = {
555         .owner   = THIS_MODULE,
556         .open    = rt_cpu_seq_open,
557         .read    = seq_read,
558         .llseek  = seq_lseek,
559         .release = seq_release,
560 };
561
562 #ifdef CONFIG_IP_ROUTE_CLASSID
563 static int rt_acct_proc_show(struct seq_file *m, void *v)
564 {
565         struct ip_rt_acct *dst, *src;
566         unsigned int i, j;
567
568         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
569         if (!dst)
570                 return -ENOMEM;
571
572         for_each_possible_cpu(i) {
573                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
574                 for (j = 0; j < 256; j++) {
575                         dst[j].o_bytes   += src[j].o_bytes;
576                         dst[j].o_packets += src[j].o_packets;
577                         dst[j].i_bytes   += src[j].i_bytes;
578                         dst[j].i_packets += src[j].i_packets;
579                 }
580         }
581
582         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
583         kfree(dst);
584         return 0;
585 }
586
587 static int rt_acct_proc_open(struct inode *inode, struct file *file)
588 {
589         return single_open(file, rt_acct_proc_show, NULL);
590 }
591
592 static const struct file_operations rt_acct_proc_fops = {
593         .owner          = THIS_MODULE,
594         .open           = rt_acct_proc_open,
595         .read           = seq_read,
596         .llseek         = seq_lseek,
597         .release        = single_release,
598 };
599 #endif
600
601 static int __net_init ip_rt_do_proc_init(struct net *net)
602 {
603         struct proc_dir_entry *pde;
604
605         pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
606                         &rt_cache_seq_fops);
607         if (!pde)
608                 goto err1;
609
610         pde = proc_create("rt_cache", S_IRUGO,
611                           net->proc_net_stat, &rt_cpu_seq_fops);
612         if (!pde)
613                 goto err2;
614
615 #ifdef CONFIG_IP_ROUTE_CLASSID
616         pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
617         if (!pde)
618                 goto err3;
619 #endif
620         return 0;
621
622 #ifdef CONFIG_IP_ROUTE_CLASSID
623 err3:
624         remove_proc_entry("rt_cache", net->proc_net_stat);
625 #endif
626 err2:
627         remove_proc_entry("rt_cache", net->proc_net);
628 err1:
629         return -ENOMEM;
630 }
631
632 static void __net_exit ip_rt_do_proc_exit(struct net *net)
633 {
634         remove_proc_entry("rt_cache", net->proc_net_stat);
635         remove_proc_entry("rt_cache", net->proc_net);
636 #ifdef CONFIG_IP_ROUTE_CLASSID
637         remove_proc_entry("rt_acct", net->proc_net);
638 #endif
639 }
640
641 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
642         .init = ip_rt_do_proc_init,
643         .exit = ip_rt_do_proc_exit,
644 };
645
646 static int __init ip_rt_proc_init(void)
647 {
648         return register_pernet_subsys(&ip_rt_proc_ops);
649 }
650
651 #else
652 static inline int ip_rt_proc_init(void)
653 {
654         return 0;
655 }
656 #endif /* CONFIG_PROC_FS */
657
658 static inline void rt_free(struct rtable *rt)
659 {
660         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
661 }
662
663 static inline void rt_drop(struct rtable *rt)
664 {
665         ip_rt_put(rt);
666         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
667 }
668
669 static inline int rt_fast_clean(struct rtable *rth)
670 {
671         /* Kill broadcast/multicast entries very aggresively, if they
672            collide in hash table with more useful entries */
673         return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
674                 rt_is_input_route(rth) && rth->dst.rt_next;
675 }
676
677 static inline int rt_valuable(struct rtable *rth)
678 {
679         return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
680                 (rt_has_peer(rth) && rt_peer_ptr(rth)->pmtu_expires);
681 }
682
683 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
684 {
685         unsigned long age;
686         int ret = 0;
687
688         if (atomic_read(&rth->dst.__refcnt))
689                 goto out;
690
691         age = jiffies - rth->dst.lastuse;
692         if ((age <= tmo1 && !rt_fast_clean(rth)) ||
693             (age <= tmo2 && rt_valuable(rth)))
694                 goto out;
695         ret = 1;
696 out:    return ret;
697 }
698
699 /* Bits of score are:
700  * 31: very valuable
701  * 30: not quite useless
702  * 29..0: usage counter
703  */
704 static inline u32 rt_score(struct rtable *rt)
705 {
706         u32 score = jiffies - rt->dst.lastuse;
707
708         score = ~score & ~(3<<30);
709
710         if (rt_valuable(rt))
711                 score |= (1<<31);
712
713         if (rt_is_output_route(rt) ||
714             !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
715                 score |= (1<<30);
716
717         return score;
718 }
719
720 static inline bool rt_caching(const struct net *net)
721 {
722         return net->ipv4.current_rt_cache_rebuild_count <=
723                 net->ipv4.sysctl_rt_cache_rebuild_count;
724 }
725
726 static inline bool compare_hash_inputs(const struct rtable *rt1,
727                                        const struct rtable *rt2)
728 {
729         return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
730                 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
731                 (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0);
732 }
733
734 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2)
735 {
736         return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
737                 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
738                 (rt1->rt_mark ^ rt2->rt_mark) |
739                 (rt1->rt_key_tos ^ rt2->rt_key_tos) |
740                 (rt1->rt_route_iif ^ rt2->rt_route_iif) |
741                 (rt1->rt_oif ^ rt2->rt_oif)) == 0;
742 }
743
744 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
745 {
746         return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev));
747 }
748
749 static inline int rt_is_expired(struct rtable *rth)
750 {
751         return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
752 }
753
754 /*
755  * Perform a full scan of hash table and free all entries.
756  * Can be called by a softirq or a process.
757  * In the later case, we want to be reschedule if necessary
758  */
759 static void rt_do_flush(struct net *net, int process_context)
760 {
761         unsigned int i;
762         struct rtable *rth, *next;
763
764         for (i = 0; i <= rt_hash_mask; i++) {
765                 struct rtable __rcu **pprev;
766                 struct rtable *list;
767
768                 if (process_context && need_resched())
769                         cond_resched();
770                 rth = rcu_access_pointer(rt_hash_table[i].chain);
771                 if (!rth)
772                         continue;
773
774                 spin_lock_bh(rt_hash_lock_addr(i));
775
776                 list = NULL;
777                 pprev = &rt_hash_table[i].chain;
778                 rth = rcu_dereference_protected(*pprev,
779                         lockdep_is_held(rt_hash_lock_addr(i)));
780
781                 while (rth) {
782                         next = rcu_dereference_protected(rth->dst.rt_next,
783                                 lockdep_is_held(rt_hash_lock_addr(i)));
784
785                         if (!net ||
786                             net_eq(dev_net(rth->dst.dev), net)) {
787                                 rcu_assign_pointer(*pprev, next);
788                                 rcu_assign_pointer(rth->dst.rt_next, list);
789                                 list = rth;
790                         } else {
791                                 pprev = &rth->dst.rt_next;
792                         }
793                         rth = next;
794                 }
795
796                 spin_unlock_bh(rt_hash_lock_addr(i));
797
798                 for (; list; list = next) {
799                         next = rcu_dereference_protected(list->dst.rt_next, 1);
800                         rt_free(list);
801                 }
802         }
803 }
804
805 /*
806  * While freeing expired entries, we compute average chain length
807  * and standard deviation, using fixed-point arithmetic.
808  * This to have an estimation of rt_chain_length_max
809  *  rt_chain_length_max = max(elasticity, AVG + 4*SD)
810  * We use 3 bits for frational part, and 29 (or 61) for magnitude.
811  */
812
813 #define FRACT_BITS 3
814 #define ONE (1UL << FRACT_BITS)
815
816 /*
817  * Given a hash chain and an item in this hash chain,
818  * find if a previous entry has the same hash_inputs
819  * (but differs on tos, mark or oif)
820  * Returns 0 if an alias is found.
821  * Returns ONE if rth has no alias before itself.
822  */
823 static int has_noalias(const struct rtable *head, const struct rtable *rth)
824 {
825         const struct rtable *aux = head;
826
827         while (aux != rth) {
828                 if (compare_hash_inputs(aux, rth))
829                         return 0;
830                 aux = rcu_dereference_protected(aux->dst.rt_next, 1);
831         }
832         return ONE;
833 }
834
835 static void rt_check_expire(void)
836 {
837         static unsigned int rover;
838         unsigned int i = rover, goal;
839         struct rtable *rth;
840         struct rtable __rcu **rthp;
841         unsigned long samples = 0;
842         unsigned long sum = 0, sum2 = 0;
843         unsigned long delta;
844         u64 mult;
845
846         delta = jiffies - expires_ljiffies;
847         expires_ljiffies = jiffies;
848         mult = ((u64)delta) << rt_hash_log;
849         if (ip_rt_gc_timeout > 1)
850                 do_div(mult, ip_rt_gc_timeout);
851         goal = (unsigned int)mult;
852         if (goal > rt_hash_mask)
853                 goal = rt_hash_mask + 1;
854         for (; goal > 0; goal--) {
855                 unsigned long tmo = ip_rt_gc_timeout;
856                 unsigned long length;
857
858                 i = (i + 1) & rt_hash_mask;
859                 rthp = &rt_hash_table[i].chain;
860
861                 if (need_resched())
862                         cond_resched();
863
864                 samples++;
865
866                 if (rcu_dereference_raw(*rthp) == NULL)
867                         continue;
868                 length = 0;
869                 spin_lock_bh(rt_hash_lock_addr(i));
870                 while ((rth = rcu_dereference_protected(*rthp,
871                                         lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) {
872                         prefetch(rth->dst.rt_next);
873                         if (rt_is_expired(rth) ||
874                             rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
875                                 *rthp = rth->dst.rt_next;
876                                 rt_free(rth);
877                                 continue;
878                         }
879
880                         /* We only count entries on a chain with equal
881                          * hash inputs once so that entries for
882                          * different QOS levels, and other non-hash
883                          * input attributes don't unfairly skew the
884                          * length computation
885                          */
886                         tmo >>= 1;
887                         rthp = &rth->dst.rt_next;
888                         length += has_noalias(rt_hash_table[i].chain, rth);
889                 }
890                 spin_unlock_bh(rt_hash_lock_addr(i));
891                 sum += length;
892                 sum2 += length*length;
893         }
894         if (samples) {
895                 unsigned long avg = sum / samples;
896                 unsigned long sd = int_sqrt(sum2 / samples - avg*avg);
897                 rt_chain_length_max = max_t(unsigned long,
898                                         ip_rt_gc_elasticity,
899                                         (avg + 4*sd) >> FRACT_BITS);
900         }
901         rover = i;
902 }
903
904 /*
905  * rt_worker_func() is run in process context.
906  * we call rt_check_expire() to scan part of the hash table
907  */
908 static void rt_worker_func(struct work_struct *work)
909 {
910         rt_check_expire();
911         schedule_delayed_work(&expires_work, ip_rt_gc_interval);
912 }
913
914 /*
915  * Perturbation of rt_genid by a small quantity [1..256]
916  * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
917  * many times (2^24) without giving recent rt_genid.
918  * Jenkins hash is strong enough that litle changes of rt_genid are OK.
919  */
920 static void rt_cache_invalidate(struct net *net)
921 {
922         unsigned char shuffle;
923
924         get_random_bytes(&shuffle, sizeof(shuffle));
925         atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
926         inetpeer_invalidate_family(AF_INET);
927 }
928
929 /*
930  * delay < 0  : invalidate cache (fast : entries will be deleted later)
931  * delay >= 0 : invalidate & flush cache (can be long)
932  */
933 void rt_cache_flush(struct net *net, int delay)
934 {
935         rt_cache_invalidate(net);
936         if (delay >= 0)
937                 rt_do_flush(net, !in_softirq());
938 }
939
940 /* Flush previous cache invalidated entries from the cache */
941 void rt_cache_flush_batch(struct net *net)
942 {
943         rt_do_flush(net, !in_softirq());
944 }
945
946 static void rt_emergency_hash_rebuild(struct net *net)
947 {
948         net_warn_ratelimited("Route hash chain too long!\n");
949         rt_cache_invalidate(net);
950 }
951
952 /*
953    Short description of GC goals.
954
955    We want to build algorithm, which will keep routing cache
956    at some equilibrium point, when number of aged off entries
957    is kept approximately equal to newly generated ones.
958
959    Current expiration strength is variable "expire".
960    We try to adjust it dynamically, so that if networking
961    is idle expires is large enough to keep enough of warm entries,
962    and when load increases it reduces to limit cache size.
963  */
964
965 static int rt_garbage_collect(struct dst_ops *ops)
966 {
967         static unsigned long expire = RT_GC_TIMEOUT;
968         static unsigned long last_gc;
969         static int rover;
970         static int equilibrium;
971         struct rtable *rth;
972         struct rtable __rcu **rthp;
973         unsigned long now = jiffies;
974         int goal;
975         int entries = dst_entries_get_fast(&ipv4_dst_ops);
976
977         /*
978          * Garbage collection is pretty expensive,
979          * do not make it too frequently.
980          */
981
982         RT_CACHE_STAT_INC(gc_total);
983
984         if (now - last_gc < ip_rt_gc_min_interval &&
985             entries < ip_rt_max_size) {
986                 RT_CACHE_STAT_INC(gc_ignored);
987                 goto out;
988         }
989
990         entries = dst_entries_get_slow(&ipv4_dst_ops);
991         /* Calculate number of entries, which we want to expire now. */
992         goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
993         if (goal <= 0) {
994                 if (equilibrium < ipv4_dst_ops.gc_thresh)
995                         equilibrium = ipv4_dst_ops.gc_thresh;
996                 goal = entries - equilibrium;
997                 if (goal > 0) {
998                         equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
999                         goal = entries - equilibrium;
1000                 }
1001         } else {
1002                 /* We are in dangerous area. Try to reduce cache really
1003                  * aggressively.
1004                  */
1005                 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
1006                 equilibrium = entries - goal;
1007         }
1008
1009         if (now - last_gc >= ip_rt_gc_min_interval)
1010                 last_gc = now;
1011
1012         if (goal <= 0) {
1013                 equilibrium += goal;
1014                 goto work_done;
1015         }
1016
1017         do {
1018                 int i, k;
1019
1020                 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
1021                         unsigned long tmo = expire;
1022
1023                         k = (k + 1) & rt_hash_mask;
1024                         rthp = &rt_hash_table[k].chain;
1025                         spin_lock_bh(rt_hash_lock_addr(k));
1026                         while ((rth = rcu_dereference_protected(*rthp,
1027                                         lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
1028                                 if (!rt_is_expired(rth) &&
1029                                         !rt_may_expire(rth, tmo, expire)) {
1030                                         tmo >>= 1;
1031                                         rthp = &rth->dst.rt_next;
1032                                         continue;
1033                                 }
1034                                 *rthp = rth->dst.rt_next;
1035                                 rt_free(rth);
1036                                 goal--;
1037                         }
1038                         spin_unlock_bh(rt_hash_lock_addr(k));
1039                         if (goal <= 0)
1040                                 break;
1041                 }
1042                 rover = k;
1043
1044                 if (goal <= 0)
1045                         goto work_done;
1046
1047                 /* Goal is not achieved. We stop process if:
1048
1049                    - if expire reduced to zero. Otherwise, expire is halfed.
1050                    - if table is not full.
1051                    - if we are called from interrupt.
1052                    - jiffies check is just fallback/debug loop breaker.
1053                      We will not spin here for long time in any case.
1054                  */
1055
1056                 RT_CACHE_STAT_INC(gc_goal_miss);
1057
1058                 if (expire == 0)
1059                         break;
1060
1061                 expire >>= 1;
1062
1063                 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1064                         goto out;
1065         } while (!in_softirq() && time_before_eq(jiffies, now));
1066
1067         if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1068                 goto out;
1069         if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
1070                 goto out;
1071         net_warn_ratelimited("dst cache overflow\n");
1072         RT_CACHE_STAT_INC(gc_dst_overflow);
1073         return 1;
1074
1075 work_done:
1076         expire += ip_rt_gc_min_interval;
1077         if (expire > ip_rt_gc_timeout ||
1078             dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
1079             dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
1080                 expire = ip_rt_gc_timeout;
1081 out:    return 0;
1082 }
1083
1084 /*
1085  * Returns number of entries in a hash chain that have different hash_inputs
1086  */
1087 static int slow_chain_length(const struct rtable *head)
1088 {
1089         int length = 0;
1090         const struct rtable *rth = head;
1091
1092         while (rth) {
1093                 length += has_noalias(head, rth);
1094                 rth = rcu_dereference_protected(rth->dst.rt_next, 1);
1095         }
1096         return length >> FRACT_BITS;
1097 }
1098
1099 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr)
1100 {
1101         static const __be32 inaddr_any = 0;
1102         struct net_device *dev = dst->dev;
1103         const __be32 *pkey = daddr;
1104         const struct rtable *rt;
1105         struct neighbour *n;
1106
1107         rt = (const struct rtable *) dst;
1108
1109         if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
1110                 pkey = &inaddr_any;
1111         else if (rt->rt_gateway)
1112                 pkey = (const __be32 *) &rt->rt_gateway;
1113
1114         n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
1115         if (n)
1116                 return n;
1117         return neigh_create(&arp_tbl, pkey, dev);
1118 }
1119
1120 static int rt_bind_neighbour(struct rtable *rt)
1121 {
1122         struct neighbour *n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1123         if (IS_ERR(n))
1124                 return PTR_ERR(n);
1125         dst_set_neighbour(&rt->dst, n);
1126
1127         return 0;
1128 }
1129
1130 static struct rtable *rt_intern_hash(unsigned int hash, struct rtable *rt,
1131                                      struct sk_buff *skb, int ifindex)
1132 {
1133         struct rtable   *rth, *cand;
1134         struct rtable __rcu **rthp, **candp;
1135         unsigned long   now;
1136         u32             min_score;
1137         int             chain_length;
1138         int attempts = !in_softirq();
1139
1140 restart:
1141         chain_length = 0;
1142         min_score = ~(u32)0;
1143         cand = NULL;
1144         candp = NULL;
1145         now = jiffies;
1146
1147         if (!rt_caching(dev_net(rt->dst.dev)) || (rt->dst.flags & DST_NOCACHE)) {
1148                 /*
1149                  * If we're not caching, just tell the caller we
1150                  * were successful and don't touch the route.  The
1151                  * caller hold the sole reference to the cache entry, and
1152                  * it will be released when the caller is done with it.
1153                  * If we drop it here, the callers have no way to resolve routes
1154                  * when we're not caching.  Instead, just point *rp at rt, so
1155                  * the caller gets a single use out of the route
1156                  * Note that we do rt_free on this new route entry, so that
1157                  * once its refcount hits zero, we are still able to reap it
1158                  * (Thanks Alexey)
1159                  * Note: To avoid expensive rcu stuff for this uncached dst,
1160                  * we set DST_NOCACHE so that dst_release() can free dst without
1161                  * waiting a grace period.
1162                  */
1163
1164                 rt->dst.flags |= DST_NOCACHE;
1165                 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1166                         int err = rt_bind_neighbour(rt);
1167                         if (err) {
1168                                 net_warn_ratelimited("Neighbour table failure & not caching routes\n");
1169                                 ip_rt_put(rt);
1170                                 return ERR_PTR(err);
1171                         }
1172                 }
1173
1174                 goto skip_hashing;
1175         }
1176
1177         rthp = &rt_hash_table[hash].chain;
1178
1179         spin_lock_bh(rt_hash_lock_addr(hash));
1180         while ((rth = rcu_dereference_protected(*rthp,
1181                         lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1182                 if (rt_is_expired(rth)) {
1183                         *rthp = rth->dst.rt_next;
1184                         rt_free(rth);
1185                         continue;
1186                 }
1187                 if (compare_keys(rth, rt) && compare_netns(rth, rt)) {
1188                         /* Put it first */
1189                         *rthp = rth->dst.rt_next;
1190                         /*
1191                          * Since lookup is lockfree, the deletion
1192                          * must be visible to another weakly ordered CPU before
1193                          * the insertion at the start of the hash chain.
1194                          */
1195                         rcu_assign_pointer(rth->dst.rt_next,
1196                                            rt_hash_table[hash].chain);
1197                         /*
1198                          * Since lookup is lockfree, the update writes
1199                          * must be ordered for consistency on SMP.
1200                          */
1201                         rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1202
1203                         dst_use(&rth->dst, now);
1204                         spin_unlock_bh(rt_hash_lock_addr(hash));
1205
1206                         rt_drop(rt);
1207                         if (skb)
1208                                 skb_dst_set(skb, &rth->dst);
1209                         return rth;
1210                 }
1211
1212                 if (!atomic_read(&rth->dst.__refcnt)) {
1213                         u32 score = rt_score(rth);
1214
1215                         if (score <= min_score) {
1216                                 cand = rth;
1217                                 candp = rthp;
1218                                 min_score = score;
1219                         }
1220                 }
1221
1222                 chain_length++;
1223
1224                 rthp = &rth->dst.rt_next;
1225         }
1226
1227         if (cand) {
1228                 /* ip_rt_gc_elasticity used to be average length of chain
1229                  * length, when exceeded gc becomes really aggressive.
1230                  *
1231                  * The second limit is less certain. At the moment it allows
1232                  * only 2 entries per bucket. We will see.
1233                  */
1234                 if (chain_length > ip_rt_gc_elasticity) {
1235                         *candp = cand->dst.rt_next;
1236                         rt_free(cand);
1237                 }
1238         } else {
1239                 if (chain_length > rt_chain_length_max &&
1240                     slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
1241                         struct net *net = dev_net(rt->dst.dev);
1242                         int num = ++net->ipv4.current_rt_cache_rebuild_count;
1243                         if (!rt_caching(net)) {
1244                                 pr_warn("%s: %d rebuilds is over limit, route caching disabled\n",
1245                                         rt->dst.dev->name, num);
1246                         }
1247                         rt_emergency_hash_rebuild(net);
1248                         spin_unlock_bh(rt_hash_lock_addr(hash));
1249
1250                         hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1251                                         ifindex, rt_genid(net));
1252                         goto restart;
1253                 }
1254         }
1255
1256         /* Try to bind route to arp only if it is output
1257            route or unicast forwarding path.
1258          */
1259         if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1260                 int err = rt_bind_neighbour(rt);
1261                 if (err) {
1262                         spin_unlock_bh(rt_hash_lock_addr(hash));
1263
1264                         if (err != -ENOBUFS) {
1265                                 rt_drop(rt);
1266                                 return ERR_PTR(err);
1267                         }
1268
1269                         /* Neighbour tables are full and nothing
1270                            can be released. Try to shrink route cache,
1271                            it is most likely it holds some neighbour records.
1272                          */
1273                         if (attempts-- > 0) {
1274                                 int saved_elasticity = ip_rt_gc_elasticity;
1275                                 int saved_int = ip_rt_gc_min_interval;
1276                                 ip_rt_gc_elasticity     = 1;
1277                                 ip_rt_gc_min_interval   = 0;
1278                                 rt_garbage_collect(&ipv4_dst_ops);
1279                                 ip_rt_gc_min_interval   = saved_int;
1280                                 ip_rt_gc_elasticity     = saved_elasticity;
1281                                 goto restart;
1282                         }
1283
1284                         net_warn_ratelimited("Neighbour table overflow\n");
1285                         rt_drop(rt);
1286                         return ERR_PTR(-ENOBUFS);
1287                 }
1288         }
1289
1290         rt->dst.rt_next = rt_hash_table[hash].chain;
1291
1292         /*
1293          * Since lookup is lockfree, we must make sure
1294          * previous writes to rt are committed to memory
1295          * before making rt visible to other CPUS.
1296          */
1297         rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1298
1299         spin_unlock_bh(rt_hash_lock_addr(hash));
1300
1301 skip_hashing:
1302         if (skb)
1303                 skb_dst_set(skb, &rt->dst);
1304         return rt;
1305 }
1306
1307 static atomic_t __rt_peer_genid = ATOMIC_INIT(0);
1308
1309 static u32 rt_peer_genid(void)
1310 {
1311         return atomic_read(&__rt_peer_genid);
1312 }
1313
1314 void rt_bind_peer(struct rtable *rt, __be32 daddr, int create)
1315 {
1316         struct inet_peer_base *base;
1317         struct inet_peer *peer;
1318
1319         base = inetpeer_base_ptr(rt->_peer);
1320         if (!base)
1321                 return;
1322
1323         peer = inet_getpeer_v4(base, daddr, create);
1324         if (peer) {
1325                 if (!rt_set_peer(rt, peer))
1326                         inet_putpeer(peer);
1327                 else
1328                         rt->rt_peer_genid = rt_peer_genid();
1329         }
1330 }
1331
1332 /*
1333  * Peer allocation may fail only in serious out-of-memory conditions.  However
1334  * we still can generate some output.
1335  * Random ID selection looks a bit dangerous because we have no chances to
1336  * select ID being unique in a reasonable period of time.
1337  * But broken packet identifier may be better than no packet at all.
1338  */
1339 static void ip_select_fb_ident(struct iphdr *iph)
1340 {
1341         static DEFINE_SPINLOCK(ip_fb_id_lock);
1342         static u32 ip_fallback_id;
1343         u32 salt;
1344
1345         spin_lock_bh(&ip_fb_id_lock);
1346         salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1347         iph->id = htons(salt & 0xFFFF);
1348         ip_fallback_id = salt;
1349         spin_unlock_bh(&ip_fb_id_lock);
1350 }
1351
1352 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1353 {
1354         struct rtable *rt = (struct rtable *) dst;
1355
1356         if (rt && !(rt->dst.flags & DST_NOPEER)) {
1357                 struct inet_peer *peer = rt_get_peer_create(rt, rt->rt_dst);
1358
1359                 /* If peer is attached to destination, it is never detached,
1360                    so that we need not to grab a lock to dereference it.
1361                  */
1362                 if (peer) {
1363                         iph->id = htons(inet_getid(peer, more));
1364                         return;
1365                 }
1366         } else if (!rt)
1367                 pr_debug("rt_bind_peer(0) @%p\n", __builtin_return_address(0));
1368
1369         ip_select_fb_ident(iph);
1370 }
1371 EXPORT_SYMBOL(__ip_select_ident);
1372
1373 static void rt_del(unsigned int hash, struct rtable *rt)
1374 {
1375         struct rtable __rcu **rthp;
1376         struct rtable *aux;
1377
1378         rthp = &rt_hash_table[hash].chain;
1379         spin_lock_bh(rt_hash_lock_addr(hash));
1380         ip_rt_put(rt);
1381         while ((aux = rcu_dereference_protected(*rthp,
1382                         lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1383                 if (aux == rt || rt_is_expired(aux)) {
1384                         *rthp = aux->dst.rt_next;
1385                         rt_free(aux);
1386                         continue;
1387                 }
1388                 rthp = &aux->dst.rt_next;
1389         }
1390         spin_unlock_bh(rt_hash_lock_addr(hash));
1391 }
1392
1393 static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
1394 {
1395         struct rtable *rt = (struct rtable *) dst;
1396         __be32 orig_gw = rt->rt_gateway;
1397         struct neighbour *n, *old_n;
1398
1399         dst_confirm(&rt->dst);
1400
1401         rt->rt_gateway = peer->redirect_learned.a4;
1402
1403         n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1404         if (IS_ERR(n)) {
1405                 rt->rt_gateway = orig_gw;
1406                 return;
1407         }
1408         old_n = xchg(&rt->dst._neighbour, n);
1409         if (old_n)
1410                 neigh_release(old_n);
1411         if (!(n->nud_state & NUD_VALID)) {
1412                 neigh_event_send(n, NULL);
1413         } else {
1414                 rt->rt_flags |= RTCF_REDIRECTED;
1415                 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
1416         }
1417 }
1418
1419 /* called in rcu_read_lock() section */
1420 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1421                     __be32 saddr, struct net_device *dev)
1422 {
1423         int s, i;
1424         struct in_device *in_dev = __in_dev_get_rcu(dev);
1425         __be32 skeys[2] = { saddr, 0 };
1426         int    ikeys[2] = { dev->ifindex, 0 };
1427         struct inet_peer *peer;
1428         struct net *net;
1429
1430         if (!in_dev)
1431                 return;
1432
1433         net = dev_net(dev);
1434         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1435             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1436             ipv4_is_zeronet(new_gw))
1437                 goto reject_redirect;
1438
1439         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1440                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1441                         goto reject_redirect;
1442                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1443                         goto reject_redirect;
1444         } else {
1445                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1446                         goto reject_redirect;
1447         }
1448
1449         for (s = 0; s < 2; s++) {
1450                 for (i = 0; i < 2; i++) {
1451                         unsigned int hash;
1452                         struct rtable __rcu **rthp;
1453                         struct rtable *rt;
1454
1455                         hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net));
1456
1457                         rthp = &rt_hash_table[hash].chain;
1458
1459                         while ((rt = rcu_dereference(*rthp)) != NULL) {
1460                                 rthp = &rt->dst.rt_next;
1461
1462                                 if (rt->rt_key_dst != daddr ||
1463                                     rt->rt_key_src != skeys[s] ||
1464                                     rt->rt_oif != ikeys[i] ||
1465                                     rt_is_input_route(rt) ||
1466                                     rt_is_expired(rt) ||
1467                                     !net_eq(dev_net(rt->dst.dev), net) ||
1468                                     rt->dst.error ||
1469                                     rt->dst.dev != dev ||
1470                                     rt->rt_gateway != old_gw)
1471                                         continue;
1472
1473                                 peer = rt_get_peer_create(rt, rt->rt_dst);
1474                                 if (peer) {
1475                                         if (peer->redirect_learned.a4 != new_gw) {
1476                                                 peer->redirect_learned.a4 = new_gw;
1477                                                 atomic_inc(&__rt_peer_genid);
1478                                         }
1479                                         check_peer_redir(&rt->dst, peer);
1480                                 }
1481                         }
1482                 }
1483         }
1484         return;
1485
1486 reject_redirect:
1487 #ifdef CONFIG_IP_ROUTE_VERBOSE
1488         if (IN_DEV_LOG_MARTIANS(in_dev))
1489                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
1490                                      "  Advised path = %pI4 -> %pI4\n",
1491                                      &old_gw, dev->name, &new_gw,
1492                                      &saddr, &daddr);
1493 #endif
1494         ;
1495 }
1496
1497 static bool peer_pmtu_expired(struct inet_peer *peer)
1498 {
1499         unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1500
1501         return orig &&
1502                time_after_eq(jiffies, orig) &&
1503                cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1504 }
1505
1506 static bool peer_pmtu_cleaned(struct inet_peer *peer)
1507 {
1508         unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1509
1510         return orig &&
1511                cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1512 }
1513
1514 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1515 {
1516         struct rtable *rt = (struct rtable *)dst;
1517         struct dst_entry *ret = dst;
1518
1519         if (rt) {
1520                 if (dst->obsolete > 0) {
1521                         ip_rt_put(rt);
1522                         ret = NULL;
1523                 } else if (rt->rt_flags & RTCF_REDIRECTED) {
1524                         unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1525                                                 rt->rt_oif,
1526                                                 rt_genid(dev_net(dst->dev)));
1527                         rt_del(hash, rt);
1528                         ret = NULL;
1529                 } else if (rt_has_peer(rt)) {
1530                         struct inet_peer *peer = rt_peer_ptr(rt);
1531                         if (peer_pmtu_expired(peer))
1532                                 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1533                 }
1534         }
1535         return ret;
1536 }
1537
1538 /*
1539  * Algorithm:
1540  *      1. The first ip_rt_redirect_number redirects are sent
1541  *         with exponential backoff, then we stop sending them at all,
1542  *         assuming that the host ignores our redirects.
1543  *      2. If we did not see packets requiring redirects
1544  *         during ip_rt_redirect_silence, we assume that the host
1545  *         forgot redirected route and start to send redirects again.
1546  *
1547  * This algorithm is much cheaper and more intelligent than dumb load limiting
1548  * in icmp.c.
1549  *
1550  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1551  * and "frag. need" (breaks PMTU discovery) in icmp.c.
1552  */
1553
1554 void ip_rt_send_redirect(struct sk_buff *skb)
1555 {
1556         struct rtable *rt = skb_rtable(skb);
1557         struct in_device *in_dev;
1558         struct inet_peer *peer;
1559         int log_martians;
1560
1561         rcu_read_lock();
1562         in_dev = __in_dev_get_rcu(rt->dst.dev);
1563         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1564                 rcu_read_unlock();
1565                 return;
1566         }
1567         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1568         rcu_read_unlock();
1569
1570         peer = rt_get_peer_create(rt, rt->rt_dst);
1571         if (!peer) {
1572                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1573                 return;
1574         }
1575
1576         /* No redirected packets during ip_rt_redirect_silence;
1577          * reset the algorithm.
1578          */
1579         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1580                 peer->rate_tokens = 0;
1581
1582         /* Too many ignored redirects; do not send anything
1583          * set dst.rate_last to the last seen redirected packet.
1584          */
1585         if (peer->rate_tokens >= ip_rt_redirect_number) {
1586                 peer->rate_last = jiffies;
1587                 return;
1588         }
1589
1590         /* Check for load limit; set rate_last to the latest sent
1591          * redirect.
1592          */
1593         if (peer->rate_tokens == 0 ||
1594             time_after(jiffies,
1595                        (peer->rate_last +
1596                         (ip_rt_redirect_load << peer->rate_tokens)))) {
1597                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1598                 peer->rate_last = jiffies;
1599                 ++peer->rate_tokens;
1600 #ifdef CONFIG_IP_ROUTE_VERBOSE
1601                 if (log_martians &&
1602                     peer->rate_tokens == ip_rt_redirect_number)
1603                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
1604                                              &ip_hdr(skb)->saddr, rt->rt_iif,
1605                                              &rt->rt_dst, &rt->rt_gateway);
1606 #endif
1607         }
1608 }
1609
1610 static int ip_error(struct sk_buff *skb)
1611 {
1612         struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
1613         struct rtable *rt = skb_rtable(skb);
1614         struct inet_peer *peer;
1615         unsigned long now;
1616         struct net *net;
1617         bool send;
1618         int code;
1619
1620         net = dev_net(rt->dst.dev);
1621         if (!IN_DEV_FORWARD(in_dev)) {
1622                 switch (rt->dst.error) {
1623                 case EHOSTUNREACH:
1624                         IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
1625                         break;
1626
1627                 case ENETUNREACH:
1628                         IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
1629                         break;
1630                 }
1631                 goto out;
1632         }
1633
1634         switch (rt->dst.error) {
1635         case EINVAL:
1636         default:
1637                 goto out;
1638         case EHOSTUNREACH:
1639                 code = ICMP_HOST_UNREACH;
1640                 break;
1641         case ENETUNREACH:
1642                 code = ICMP_NET_UNREACH;
1643                 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
1644                 break;
1645         case EACCES:
1646                 code = ICMP_PKT_FILTERED;
1647                 break;
1648         }
1649
1650         peer = rt_get_peer_create(rt, rt->rt_dst);
1651
1652         send = true;
1653         if (peer) {
1654                 now = jiffies;
1655                 peer->rate_tokens += now - peer->rate_last;
1656                 if (peer->rate_tokens > ip_rt_error_burst)
1657                         peer->rate_tokens = ip_rt_error_burst;
1658                 peer->rate_last = now;
1659                 if (peer->rate_tokens >= ip_rt_error_cost)
1660                         peer->rate_tokens -= ip_rt_error_cost;
1661                 else
1662                         send = false;
1663         }
1664         if (send)
1665                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1666
1667 out:    kfree_skb(skb);
1668         return 0;
1669 }
1670
1671 static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
1672 {
1673         unsigned long expires = ACCESS_ONCE(peer->pmtu_expires);
1674
1675         if (!expires)
1676                 return;
1677         if (time_before(jiffies, expires)) {
1678                 u32 orig_dst_mtu = dst_mtu(dst);
1679                 if (peer->pmtu_learned < orig_dst_mtu) {
1680                         if (!peer->pmtu_orig)
1681                                 peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU);
1682                         dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned);
1683                 }
1684         } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires)
1685                 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1686 }
1687
1688 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1689 {
1690         struct rtable *rt = (struct rtable *) dst;
1691         struct inet_peer *peer;
1692
1693         dst_confirm(dst);
1694
1695         peer = rt_get_peer_create(rt, rt->rt_dst);
1696         if (peer) {
1697                 unsigned long pmtu_expires = ACCESS_ONCE(peer->pmtu_expires);
1698
1699                 if (mtu < ip_rt_min_pmtu)
1700                         mtu = ip_rt_min_pmtu;
1701                 if (!pmtu_expires || mtu < peer->pmtu_learned) {
1702
1703                         pmtu_expires = jiffies + ip_rt_mtu_expires;
1704                         if (!pmtu_expires)
1705                                 pmtu_expires = 1UL;
1706
1707                         peer->pmtu_learned = mtu;
1708                         peer->pmtu_expires = pmtu_expires;
1709
1710                         atomic_inc(&__rt_peer_genid);
1711                         rt->rt_peer_genid = rt_peer_genid();
1712                 }
1713                 check_peer_pmtu(dst, peer);
1714         }
1715 }
1716
1717 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1718                       int oif, u32 mark, u8 protocol, int flow_flags)
1719 {
1720         const struct iphdr *iph = (const struct iphdr *)skb->data;
1721         struct flowi4 fl4;
1722         struct rtable *rt;
1723
1724         flowi4_init_output(&fl4, oif, mark, RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
1725                            protocol, flow_flags | FLOWI_FLAG_PRECOW_METRICS,
1726                            iph->daddr, iph->saddr, 0, 0);
1727         rt = __ip_route_output_key(net, &fl4);
1728         if (!IS_ERR(rt)) {
1729                 ip_rt_update_pmtu(&rt->dst, mtu);
1730                 ip_rt_put(rt);
1731         }
1732 }
1733 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1734
1735 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1736 {
1737         const struct inet_sock *inet = inet_sk(sk);
1738
1739         return ipv4_update_pmtu(skb, sock_net(sk), mtu,
1740                                 sk->sk_bound_dev_if, sk->sk_mark,
1741                                 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
1742                                 inet_sk_flowi_flags(sk));
1743 }
1744 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1745
1746 static void ipv4_validate_peer(struct rtable *rt)
1747 {
1748         if (rt->rt_peer_genid != rt_peer_genid()) {
1749                 struct inet_peer *peer = rt_get_peer(rt, rt->rt_dst);
1750
1751                 if (peer) {
1752                         check_peer_pmtu(&rt->dst, peer);
1753
1754                         if (peer->redirect_learned.a4 &&
1755                             peer->redirect_learned.a4 != rt->rt_gateway)
1756                                 check_peer_redir(&rt->dst, peer);
1757                 }
1758
1759                 rt->rt_peer_genid = rt_peer_genid();
1760         }
1761 }
1762
1763 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1764 {
1765         struct rtable *rt = (struct rtable *) dst;
1766
1767         if (rt_is_expired(rt))
1768                 return NULL;
1769         ipv4_validate_peer(rt);
1770         return dst;
1771 }
1772
1773 static void ipv4_dst_destroy(struct dst_entry *dst)
1774 {
1775         struct rtable *rt = (struct rtable *) dst;
1776
1777         if (rt->fi) {
1778                 fib_info_put(rt->fi);
1779                 rt->fi = NULL;
1780         }
1781         if (rt_has_peer(rt)) {
1782                 struct inet_peer *peer = rt_peer_ptr(rt);
1783                 inet_putpeer(peer);
1784         }
1785 }
1786
1787
1788 static void ipv4_link_failure(struct sk_buff *skb)
1789 {
1790         struct rtable *rt;
1791
1792         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1793
1794         rt = skb_rtable(skb);
1795         if (rt && rt_has_peer(rt)) {
1796                 struct inet_peer *peer = rt_peer_ptr(rt);
1797                 if (peer_pmtu_cleaned(peer))
1798                         dst_metric_set(&rt->dst, RTAX_MTU, peer->pmtu_orig);
1799         }
1800 }
1801
1802 static int ip_rt_bug(struct sk_buff *skb)
1803 {
1804         pr_debug("%s: %pI4 -> %pI4, %s\n",
1805                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1806                  skb->dev ? skb->dev->name : "?");
1807         kfree_skb(skb);
1808         WARN_ON(1);
1809         return 0;
1810 }
1811
1812 /*
1813    We do not cache source address of outgoing interface,
1814    because it is used only by IP RR, TS and SRR options,
1815    so that it out of fast path.
1816
1817    BTW remember: "addr" is allowed to be not aligned
1818    in IP options!
1819  */
1820
1821 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1822 {
1823         __be32 src;
1824
1825         if (rt_is_output_route(rt))
1826                 src = ip_hdr(skb)->saddr;
1827         else {
1828                 struct fib_result res;
1829                 struct flowi4 fl4;
1830                 struct iphdr *iph;
1831
1832                 iph = ip_hdr(skb);
1833
1834                 memset(&fl4, 0, sizeof(fl4));
1835                 fl4.daddr = iph->daddr;
1836                 fl4.saddr = iph->saddr;
1837                 fl4.flowi4_tos = RT_TOS(iph->tos);
1838                 fl4.flowi4_oif = rt->dst.dev->ifindex;
1839                 fl4.flowi4_iif = skb->dev->ifindex;
1840                 fl4.flowi4_mark = skb->mark;
1841
1842                 rcu_read_lock();
1843                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1844                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1845                 else
1846                         src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1847                                         RT_SCOPE_UNIVERSE);
1848                 rcu_read_unlock();
1849         }
1850         memcpy(addr, &src, 4);
1851 }
1852
1853 #ifdef CONFIG_IP_ROUTE_CLASSID
1854 static void set_class_tag(struct rtable *rt, u32 tag)
1855 {
1856         if (!(rt->dst.tclassid & 0xFFFF))
1857                 rt->dst.tclassid |= tag & 0xFFFF;
1858         if (!(rt->dst.tclassid & 0xFFFF0000))
1859                 rt->dst.tclassid |= tag & 0xFFFF0000;
1860 }
1861 #endif
1862
1863 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1864 {
1865         unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1866
1867         if (advmss == 0) {
1868                 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1869                                ip_rt_min_advmss);
1870                 if (advmss > 65535 - 40)
1871                         advmss = 65535 - 40;
1872         }
1873         return advmss;
1874 }
1875
1876 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1877 {
1878         const struct rtable *rt = (const struct rtable *) dst;
1879         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1880
1881         if (mtu && rt_is_output_route(rt))
1882                 return mtu;
1883
1884         mtu = dst->dev->mtu;
1885
1886         if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1887
1888                 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1889                         mtu = 576;
1890         }
1891
1892         if (mtu > IP_MAX_MTU)
1893                 mtu = IP_MAX_MTU;
1894
1895         return mtu;
1896 }
1897
1898 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1899                             struct fib_info *fi)
1900 {
1901         struct inet_peer_base *base;
1902         struct inet_peer *peer;
1903         int create = 0;
1904
1905         /* If a peer entry exists for this destination, we must hook
1906          * it up in order to get at cached metrics.
1907          */
1908         if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
1909                 create = 1;
1910
1911         base = inetpeer_base_ptr(rt->_peer);
1912         BUG_ON(!base);
1913
1914         peer = inet_getpeer_v4(base, rt->rt_dst, create);
1915         if (peer) {
1916                 __rt_set_peer(rt, peer);
1917                 rt->rt_peer_genid = rt_peer_genid();
1918                 if (inet_metrics_new(peer))
1919                         memcpy(peer->metrics, fi->fib_metrics,
1920                                sizeof(u32) * RTAX_MAX);
1921                 dst_init_metrics(&rt->dst, peer->metrics, false);
1922
1923                 check_peer_pmtu(&rt->dst, peer);
1924
1925                 if (peer->redirect_learned.a4 &&
1926                     peer->redirect_learned.a4 != rt->rt_gateway) {
1927                         rt->rt_gateway = peer->redirect_learned.a4;
1928                         rt->rt_flags |= RTCF_REDIRECTED;
1929                 }
1930         } else {
1931                 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1932                         rt->fi = fi;
1933                         atomic_inc(&fi->fib_clntref);
1934                 }
1935                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1936         }
1937 }
1938
1939 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1940                            const struct fib_result *res,
1941                            struct fib_info *fi, u16 type, u32 itag)
1942 {
1943         struct dst_entry *dst = &rt->dst;
1944
1945         if (fi) {
1946                 if (FIB_RES_GW(*res) &&
1947                     FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1948                         rt->rt_gateway = FIB_RES_GW(*res);
1949                 rt_init_metrics(rt, fl4, fi);
1950 #ifdef CONFIG_IP_ROUTE_CLASSID
1951                 dst->tclassid = FIB_RES_NH(*res).nh_tclassid;
1952 #endif
1953         }
1954
1955         if (dst_mtu(dst) > IP_MAX_MTU)
1956                 dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);
1957
1958 #ifdef CONFIG_IP_ROUTE_CLASSID
1959 #ifdef CONFIG_IP_MULTIPLE_TABLES
1960         set_class_tag(rt, fib_rules_tclass(res));
1961 #endif
1962         set_class_tag(rt, itag);
1963 #endif
1964 }
1965
1966 static struct rtable *rt_dst_alloc(struct net_device *dev,
1967                                    bool nopolicy, bool noxfrm)
1968 {
1969         return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
1970                          DST_HOST |
1971                          (nopolicy ? DST_NOPOLICY : 0) |
1972                          (noxfrm ? DST_NOXFRM : 0));
1973 }
1974
1975 /* called in rcu_read_lock() section */
1976 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1977                                 u8 tos, struct net_device *dev, int our)
1978 {
1979         unsigned int hash;
1980         struct rtable *rth;
1981         struct in_device *in_dev = __in_dev_get_rcu(dev);
1982         u32 itag = 0;
1983         int err;
1984
1985         /* Primary sanity checks. */
1986
1987         if (in_dev == NULL)
1988                 return -EINVAL;
1989
1990         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1991             skb->protocol != htons(ETH_P_IP))
1992                 goto e_inval;
1993
1994         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1995                 if (ipv4_is_loopback(saddr))
1996                         goto e_inval;
1997
1998         if (ipv4_is_zeronet(saddr)) {
1999                 if (!ipv4_is_local_multicast(daddr))
2000                         goto e_inval;
2001         } else {
2002                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2003                                           in_dev, &itag);
2004                 if (err < 0)
2005                         goto e_err;
2006         }
2007         rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
2008                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2009         if (!rth)
2010                 goto e_nobufs;
2011
2012 #ifdef CONFIG_IP_ROUTE_CLASSID
2013         rth->dst.tclassid = itag;
2014 #endif
2015         rth->dst.output = ip_rt_bug;
2016
2017         rth->rt_key_dst = daddr;
2018         rth->rt_key_src = saddr;
2019         rth->rt_genid   = rt_genid(dev_net(dev));
2020         rth->rt_flags   = RTCF_MULTICAST;
2021         rth->rt_type    = RTN_MULTICAST;
2022         rth->rt_key_tos = tos;
2023         rth->rt_dst     = daddr;
2024         rth->rt_src     = saddr;
2025         rth->rt_route_iif = dev->ifindex;
2026         rth->rt_iif     = dev->ifindex;
2027         rth->rt_oif     = 0;
2028         rth->rt_mark    = skb->mark;
2029         rth->rt_gateway = daddr;
2030         rth->rt_peer_genid = 0;
2031         rt_init_peer(rth, dev_net(dev)->ipv4.peers);
2032         rth->fi = NULL;
2033         if (our) {
2034                 rth->dst.input= ip_local_deliver;
2035                 rth->rt_flags |= RTCF_LOCAL;
2036         }
2037
2038 #ifdef CONFIG_IP_MROUTE
2039         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
2040                 rth->dst.input = ip_mr_input;
2041 #endif
2042         RT_CACHE_STAT_INC(in_slow_mc);
2043
2044         hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
2045         rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
2046         return IS_ERR(rth) ? PTR_ERR(rth) : 0;
2047
2048 e_nobufs:
2049         return -ENOBUFS;
2050 e_inval:
2051         return -EINVAL;
2052 e_err:
2053         return err;
2054 }
2055
2056
2057 static void ip_handle_martian_source(struct net_device *dev,
2058                                      struct in_device *in_dev,
2059                                      struct sk_buff *skb,
2060                                      __be32 daddr,
2061                                      __be32 saddr)
2062 {
2063         RT_CACHE_STAT_INC(in_martian_src);
2064 #ifdef CONFIG_IP_ROUTE_VERBOSE
2065         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
2066                 /*
2067                  *      RFC1812 recommendation, if source is martian,
2068                  *      the only hint is MAC header.
2069                  */
2070                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
2071                         &daddr, &saddr, dev->name);
2072                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
2073                         print_hex_dump(KERN_WARNING, "ll header: ",
2074                                        DUMP_PREFIX_OFFSET, 16, 1,
2075                                        skb_mac_header(skb),
2076                                        dev->hard_header_len, true);
2077                 }
2078         }
2079 #endif
2080 }
2081
2082 /* called in rcu_read_lock() section */
2083 static int __mkroute_input(struct sk_buff *skb,
2084                            const struct fib_result *res,
2085                            struct in_device *in_dev,
2086                            __be32 daddr, __be32 saddr, u32 tos,
2087                            struct rtable **result)
2088 {
2089         struct rtable *rth;
2090         int err;
2091         struct in_device *out_dev;
2092         unsigned int flags = 0;
2093         u32 itag;
2094
2095         /* get a working reference to the output device */
2096         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
2097         if (out_dev == NULL) {
2098                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
2099                 return -EINVAL;
2100         }
2101
2102
2103         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
2104                                   in_dev->dev, in_dev, &itag);
2105         if (err < 0) {
2106                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
2107                                          saddr);
2108
2109                 goto cleanup;
2110         }
2111
2112         if (err)
2113                 flags |= RTCF_DIRECTSRC;
2114
2115         if (out_dev == in_dev && err &&
2116             (IN_DEV_SHARED_MEDIA(out_dev) ||
2117              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
2118                 flags |= RTCF_DOREDIRECT;
2119
2120         if (skb->protocol != htons(ETH_P_IP)) {
2121                 /* Not IP (i.e. ARP). Do not create route, if it is
2122                  * invalid for proxy arp. DNAT routes are always valid.
2123                  *
2124                  * Proxy arp feature have been extended to allow, ARP
2125                  * replies back to the same interface, to support
2126                  * Private VLAN switch technologies. See arp.c.
2127                  */
2128                 if (out_dev == in_dev &&
2129                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2130                         err = -EINVAL;
2131                         goto cleanup;
2132                 }
2133         }
2134
2135         rth = rt_dst_alloc(out_dev->dev,
2136                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2137                            IN_DEV_CONF_GET(out_dev, NOXFRM));
2138         if (!rth) {
2139                 err = -ENOBUFS;
2140                 goto cleanup;
2141         }
2142
2143         rth->rt_key_dst = daddr;
2144         rth->rt_key_src = saddr;
2145         rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
2146         rth->rt_flags = flags;
2147         rth->rt_type = res->type;
2148         rth->rt_key_tos = tos;
2149         rth->rt_dst     = daddr;
2150         rth->rt_src     = saddr;
2151         rth->rt_route_iif = in_dev->dev->ifindex;
2152         rth->rt_iif     = in_dev->dev->ifindex;
2153         rth->rt_oif     = 0;
2154         rth->rt_mark    = skb->mark;
2155         rth->rt_gateway = daddr;
2156         rth->rt_peer_genid = 0;
2157         rt_init_peer(rth, &res->table->tb_peers);
2158         rth->fi = NULL;
2159
2160         rth->dst.input = ip_forward;
2161         rth->dst.output = ip_output;
2162
2163         rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
2164
2165         *result = rth;
2166         err = 0;
2167  cleanup:
2168         return err;
2169 }
2170
2171 static int ip_mkroute_input(struct sk_buff *skb,
2172                             struct fib_result *res,
2173                             const struct flowi4 *fl4,
2174                             struct in_device *in_dev,
2175                             __be32 daddr, __be32 saddr, u32 tos)
2176 {
2177         struct rtable *rth = NULL;
2178         int err;
2179         unsigned int hash;
2180
2181 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2182         if (res->fi && res->fi->fib_nhs > 1)
2183                 fib_select_multipath(res);
2184 #endif
2185
2186         /* create a routing cache entry */
2187         err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
2188         if (err)
2189                 return err;
2190
2191         /* put it into the cache */
2192         hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
2193                        rt_genid(dev_net(rth->dst.dev)));
2194         rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
2195         if (IS_ERR(rth))
2196                 return PTR_ERR(rth);
2197         return 0;
2198 }
2199
2200 /*
2201  *      NOTE. We drop all the packets that has local source
2202  *      addresses, because every properly looped back packet
2203  *      must have correct destination already attached by output routine.
2204  *
2205  *      Such approach solves two big problems:
2206  *      1. Not simplex devices are handled properly.
2207  *      2. IP spoofing attempts are filtered with 100% of guarantee.
2208  *      called with rcu_read_lock()
2209  */
2210
2211 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2212                                u8 tos, struct net_device *dev)
2213 {
2214         struct fib_result res;
2215         struct in_device *in_dev = __in_dev_get_rcu(dev);
2216         struct flowi4   fl4;
2217         unsigned int    flags = 0;
2218         u32             itag = 0;
2219         struct rtable   *rth;
2220         unsigned int    hash;
2221         int             err = -EINVAL;
2222         struct net    *net = dev_net(dev);
2223
2224         /* IP on this device is disabled. */
2225
2226         if (!in_dev)
2227                 goto out;
2228
2229         /* Check for the most weird martians, which can be not detected
2230            by fib_lookup.
2231          */
2232
2233         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2234                 goto martian_source;
2235
2236         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2237                 goto brd_input;
2238
2239         /* Accept zero addresses only to limited broadcast;
2240          * I even do not know to fix it or not. Waiting for complains :-)
2241          */
2242         if (ipv4_is_zeronet(saddr))
2243                 goto martian_source;
2244
2245         if (ipv4_is_zeronet(daddr))
2246                 goto martian_destination;
2247
2248         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
2249                 if (ipv4_is_loopback(daddr))
2250                         goto martian_destination;
2251
2252                 if (ipv4_is_loopback(saddr))
2253                         goto martian_source;
2254         }
2255
2256         /*
2257          *      Now we are ready to route packet.
2258          */
2259         fl4.flowi4_oif = 0;
2260         fl4.flowi4_iif = dev->ifindex;
2261         fl4.flowi4_mark = skb->mark;
2262         fl4.flowi4_tos = tos;
2263         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2264         fl4.daddr = daddr;
2265         fl4.saddr = saddr;
2266         err = fib_lookup(net, &fl4, &res);
2267         if (err != 0)
2268                 goto no_route;
2269
2270         RT_CACHE_STAT_INC(in_slow_tot);
2271
2272         if (res.type == RTN_BROADCAST)
2273                 goto brd_input;
2274
2275         if (res.type == RTN_LOCAL) {
2276                 err = fib_validate_source(skb, saddr, daddr, tos,
2277                                           net->loopback_dev->ifindex,
2278                                           dev, in_dev, &itag);
2279                 if (err < 0)
2280                         goto martian_source_keep_err;
2281                 if (err)
2282                         flags |= RTCF_DIRECTSRC;
2283                 goto local_input;
2284         }
2285
2286         if (!IN_DEV_FORWARD(in_dev))
2287                 goto no_route;
2288         if (res.type != RTN_UNICAST)
2289                 goto martian_destination;
2290
2291         err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2292 out:    return err;
2293
2294 brd_input:
2295         if (skb->protocol != htons(ETH_P_IP))
2296                 goto e_inval;
2297
2298         if (!ipv4_is_zeronet(saddr)) {
2299                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2300                                           in_dev, &itag);
2301                 if (err < 0)
2302                         goto martian_source_keep_err;
2303                 if (err)
2304                         flags |= RTCF_DIRECTSRC;
2305         }
2306         flags |= RTCF_BROADCAST;
2307         res.type = RTN_BROADCAST;
2308         RT_CACHE_STAT_INC(in_brd);
2309
2310 local_input:
2311         rth = rt_dst_alloc(net->loopback_dev,
2312                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2313         if (!rth)
2314                 goto e_nobufs;
2315
2316         rth->dst.input= ip_local_deliver;
2317         rth->dst.output= ip_rt_bug;
2318 #ifdef CONFIG_IP_ROUTE_CLASSID
2319         rth->dst.tclassid = itag;
2320 #endif
2321
2322         rth->rt_key_dst = daddr;
2323         rth->rt_key_src = saddr;
2324         rth->rt_genid = rt_genid(net);
2325         rth->rt_flags   = flags|RTCF_LOCAL;
2326         rth->rt_type    = res.type;
2327         rth->rt_key_tos = tos;
2328         rth->rt_dst     = daddr;
2329         rth->rt_src     = saddr;
2330         rth->rt_route_iif = dev->ifindex;
2331         rth->rt_iif     = dev->ifindex;
2332         rth->rt_oif     = 0;
2333         rth->rt_mark    = skb->mark;
2334         rth->rt_gateway = daddr;
2335         rth->rt_peer_genid = 0;
2336         rt_init_peer(rth, net->ipv4.peers);
2337         rth->fi = NULL;
2338         if (res.type == RTN_UNREACHABLE) {
2339                 rth->dst.input= ip_error;
2340                 rth->dst.error= -err;
2341                 rth->rt_flags   &= ~RTCF_LOCAL;
2342         }
2343         hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2344         rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2345         err = 0;
2346         if (IS_ERR(rth))
2347                 err = PTR_ERR(rth);
2348         goto out;
2349
2350 no_route:
2351         RT_CACHE_STAT_INC(in_no_route);
2352         res.type = RTN_UNREACHABLE;
2353         if (err == -ESRCH)
2354                 err = -ENETUNREACH;
2355         goto local_input;
2356
2357         /*
2358          *      Do not cache martian addresses: they should be logged (RFC1812)
2359          */
2360 martian_destination:
2361         RT_CACHE_STAT_INC(in_martian_dst);
2362 #ifdef CONFIG_IP_ROUTE_VERBOSE
2363         if (IN_DEV_LOG_MARTIANS(in_dev))
2364                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2365                                      &daddr, &saddr, dev->name);
2366 #endif
2367
2368 e_inval:
2369         err = -EINVAL;
2370         goto out;
2371
2372 e_nobufs:
2373         err = -ENOBUFS;
2374         goto out;
2375
2376 martian_source:
2377         err = -EINVAL;
2378 martian_source_keep_err:
2379         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2380         goto out;
2381 }
2382
2383 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2384                            u8 tos, struct net_device *dev, bool noref)
2385 {
2386         struct rtable   *rth;
2387         unsigned int    hash;
2388         int iif = dev->ifindex;
2389         struct net *net;
2390         int res;
2391
2392         net = dev_net(dev);
2393
2394         rcu_read_lock();
2395
2396         if (!rt_caching(net))
2397                 goto skip_cache;
2398
2399         tos &= IPTOS_RT_MASK;
2400         hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2401
2402         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2403              rth = rcu_dereference(rth->dst.rt_next)) {
2404                 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2405                      ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2406                      (rth->rt_route_iif ^ iif) |
2407                      (rth->rt_key_tos ^ tos)) == 0 &&
2408                     rth->rt_mark == skb->mark &&
2409                     net_eq(dev_net(rth->dst.dev), net) &&
2410                     !rt_is_expired(rth)) {
2411                         ipv4_validate_peer(rth);
2412                         if (noref) {
2413                                 dst_use_noref(&rth->dst, jiffies);
2414                                 skb_dst_set_noref(skb, &rth->dst);
2415                         } else {
2416                                 dst_use(&rth->dst, jiffies);
2417                                 skb_dst_set(skb, &rth->dst);
2418                         }
2419                         RT_CACHE_STAT_INC(in_hit);
2420                         rcu_read_unlock();
2421                         return 0;
2422                 }
2423                 RT_CACHE_STAT_INC(in_hlist_search);
2424         }
2425
2426 skip_cache:
2427         /* Multicast recognition logic is moved from route cache to here.
2428            The problem was that too many Ethernet cards have broken/missing
2429            hardware multicast filters :-( As result the host on multicasting
2430            network acquires a lot of useless route cache entries, sort of
2431            SDR messages from all the world. Now we try to get rid of them.
2432            Really, provided software IP multicast filter is organized
2433            reasonably (at least, hashed), it does not result in a slowdown
2434            comparing with route cache reject entries.
2435            Note, that multicast routers are not affected, because
2436            route cache entry is created eventually.
2437          */
2438         if (ipv4_is_multicast(daddr)) {
2439                 struct in_device *in_dev = __in_dev_get_rcu(dev);
2440
2441                 if (in_dev) {
2442                         int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2443                                                   ip_hdr(skb)->protocol);
2444                         if (our
2445 #ifdef CONFIG_IP_MROUTE
2446                                 ||
2447                             (!ipv4_is_local_multicast(daddr) &&
2448                              IN_DEV_MFORWARD(in_dev))
2449 #endif
2450                            ) {
2451                                 int res = ip_route_input_mc(skb, daddr, saddr,
2452                                                             tos, dev, our);
2453                                 rcu_read_unlock();
2454                                 return res;
2455                         }
2456                 }
2457                 rcu_read_unlock();
2458                 return -EINVAL;
2459         }
2460         res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2461         rcu_read_unlock();
2462         return res;
2463 }
2464 EXPORT_SYMBOL(ip_route_input_common);
2465
2466 /* called with rcu_read_lock() */
2467 static struct rtable *__mkroute_output(const struct fib_result *res,
2468                                        const struct flowi4 *fl4,
2469                                        __be32 orig_daddr, __be32 orig_saddr,
2470                                        int orig_oif, __u8 orig_rtos,
2471                                        struct net_device *dev_out,
2472                                        unsigned int flags)
2473 {
2474         struct fib_info *fi = res->fi;
2475         struct in_device *in_dev;
2476         u16 type = res->type;
2477         struct rtable *rth;
2478
2479         in_dev = __in_dev_get_rcu(dev_out);
2480         if (!in_dev)
2481                 return ERR_PTR(-EINVAL);
2482
2483         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2484                 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2485                         return ERR_PTR(-EINVAL);
2486
2487         if (ipv4_is_lbcast(fl4->daddr))
2488                 type = RTN_BROADCAST;
2489         else if (ipv4_is_multicast(fl4->daddr))
2490                 type = RTN_MULTICAST;
2491         else if (ipv4_is_zeronet(fl4->daddr))
2492                 return ERR_PTR(-EINVAL);
2493
2494         if (dev_out->flags & IFF_LOOPBACK)
2495                 flags |= RTCF_LOCAL;
2496
2497         if (type == RTN_BROADCAST) {
2498                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2499                 fi = NULL;
2500         } else if (type == RTN_MULTICAST) {
2501                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2502                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2503                                      fl4->flowi4_proto))
2504                         flags &= ~RTCF_LOCAL;
2505                 /* If multicast route do not exist use
2506                  * default one, but do not gateway in this case.
2507                  * Yes, it is hack.
2508                  */
2509                 if (fi && res->prefixlen < 4)
2510                         fi = NULL;
2511         }
2512
2513         rth = rt_dst_alloc(dev_out,
2514                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2515                            IN_DEV_CONF_GET(in_dev, NOXFRM));
2516         if (!rth)
2517                 return ERR_PTR(-ENOBUFS);
2518
2519         rth->dst.output = ip_output;
2520
2521         rth->rt_key_dst = orig_daddr;
2522         rth->rt_key_src = orig_saddr;
2523         rth->rt_genid = rt_genid(dev_net(dev_out));
2524         rth->rt_flags   = flags;
2525         rth->rt_type    = type;
2526         rth->rt_key_tos = orig_rtos;
2527         rth->rt_dst     = fl4->daddr;
2528         rth->rt_src     = fl4->saddr;
2529         rth->rt_route_iif = 0;
2530         rth->rt_iif     = orig_oif ? : dev_out->ifindex;
2531         rth->rt_oif     = orig_oif;
2532         rth->rt_mark    = fl4->flowi4_mark;
2533         rth->rt_gateway = fl4->daddr;
2534         rth->rt_peer_genid = 0;
2535         rt_init_peer(rth, (res->table ?
2536                            &res->table->tb_peers :
2537                            dev_net(dev_out)->ipv4.peers));
2538         rth->fi = NULL;
2539
2540         RT_CACHE_STAT_INC(out_slow_tot);
2541
2542         if (flags & RTCF_LOCAL)
2543                 rth->dst.input = ip_local_deliver;
2544         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2545                 if (flags & RTCF_LOCAL &&
2546                     !(dev_out->flags & IFF_LOOPBACK)) {
2547                         rth->dst.output = ip_mc_output;
2548                         RT_CACHE_STAT_INC(out_slow_mc);
2549                 }
2550 #ifdef CONFIG_IP_MROUTE
2551                 if (type == RTN_MULTICAST) {
2552                         if (IN_DEV_MFORWARD(in_dev) &&
2553                             !ipv4_is_local_multicast(fl4->daddr)) {
2554                                 rth->dst.input = ip_mr_input;
2555                                 rth->dst.output = ip_mc_output;
2556                         }
2557                 }
2558 #endif
2559         }
2560
2561         rt_set_nexthop(rth, fl4, res, fi, type, 0);
2562
2563         if (fl4->flowi4_flags & FLOWI_FLAG_RT_NOCACHE)
2564                 rth->dst.flags |= DST_NOCACHE;
2565
2566         return rth;
2567 }
2568
2569 /*
2570  * Major route resolver routine.
2571  * called with rcu_read_lock();
2572  */
2573
2574 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4)
2575 {
2576         struct net_device *dev_out = NULL;
2577         __u8 tos = RT_FL_TOS(fl4);
2578         unsigned int flags = 0;
2579         struct fib_result res;
2580         struct rtable *rth;
2581         __be32 orig_daddr;
2582         __be32 orig_saddr;
2583         int orig_oif;
2584
2585         res.fi          = NULL;
2586         res.table       = NULL;
2587 #ifdef CONFIG_IP_MULTIPLE_TABLES
2588         res.r           = NULL;
2589 #endif
2590
2591         orig_daddr = fl4->daddr;
2592         orig_saddr = fl4->saddr;
2593         orig_oif = fl4->flowi4_oif;
2594
2595         fl4->flowi4_iif = net->loopback_dev->ifindex;
2596         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2597         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2598                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2599
2600         rcu_read_lock();
2601         if (fl4->saddr) {
2602                 rth = ERR_PTR(-EINVAL);
2603                 if (ipv4_is_multicast(fl4->saddr) ||
2604                     ipv4_is_lbcast(fl4->saddr) ||
2605                     ipv4_is_zeronet(fl4->saddr))
2606                         goto out;
2607
2608                 /* I removed check for oif == dev_out->oif here.
2609                    It was wrong for two reasons:
2610                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2611                       is assigned to multiple interfaces.
2612                    2. Moreover, we are allowed to send packets with saddr
2613                       of another iface. --ANK
2614                  */
2615
2616                 if (fl4->flowi4_oif == 0 &&
2617                     (ipv4_is_multicast(fl4->daddr) ||
2618                      ipv4_is_lbcast(fl4->daddr))) {
2619                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2620                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2621                         if (dev_out == NULL)
2622                                 goto out;
2623
2624                         /* Special hack: user can direct multicasts
2625                            and limited broadcast via necessary interface
2626                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2627                            This hack is not just for fun, it allows
2628                            vic,vat and friends to work.
2629                            They bind socket to loopback, set ttl to zero
2630                            and expect that it will work.
2631                            From the viewpoint of routing cache they are broken,
2632                            because we are not allowed to build multicast path
2633                            with loopback source addr (look, routing cache
2634                            cannot know, that ttl is zero, so that packet
2635                            will not leave this host and route is valid).
2636                            Luckily, this hack is good workaround.
2637                          */
2638
2639                         fl4->flowi4_oif = dev_out->ifindex;
2640                         goto make_route;
2641                 }
2642
2643                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2644                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2645                         if (!__ip_dev_find(net, fl4->saddr, false))
2646                                 goto out;
2647                 }
2648         }
2649
2650
2651         if (fl4->flowi4_oif) {
2652                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2653                 rth = ERR_PTR(-ENODEV);
2654                 if (dev_out == NULL)
2655                         goto out;
2656
2657                 /* RACE: Check return value of inet_select_addr instead. */
2658                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2659                         rth = ERR_PTR(-ENETUNREACH);
2660                         goto out;
2661                 }
2662                 if (ipv4_is_local_multicast(fl4->daddr) ||
2663                     ipv4_is_lbcast(fl4->daddr)) {
2664                         if (!fl4->saddr)
2665                                 fl4->saddr = inet_select_addr(dev_out, 0,
2666                                                               RT_SCOPE_LINK);
2667                         goto make_route;
2668                 }
2669                 if (fl4->saddr) {
2670                         if (ipv4_is_multicast(fl4->daddr))
2671                                 fl4->saddr = inet_select_addr(dev_out, 0,
2672                                                               fl4->flowi4_scope);
2673                         else if (!fl4->daddr)
2674                                 fl4->saddr = inet_select_addr(dev_out, 0,
2675                                                               RT_SCOPE_HOST);
2676                 }
2677         }
2678
2679         if (!fl4->daddr) {
2680                 fl4->daddr = fl4->saddr;
2681                 if (!fl4->daddr)
2682                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2683                 dev_out = net->loopback_dev;
2684                 fl4->flowi4_oif = net->loopback_dev->ifindex;
2685                 res.type = RTN_LOCAL;
2686                 flags |= RTCF_LOCAL;
2687                 goto make_route;
2688         }
2689
2690         if (fib_lookup(net, fl4, &res)) {
2691                 res.fi = NULL;
2692                 res.table = NULL;
2693                 if (fl4->flowi4_oif) {
2694                         /* Apparently, routing tables are wrong. Assume,
2695                            that the destination is on link.
2696
2697                            WHY? DW.
2698                            Because we are allowed to send to iface
2699                            even if it has NO routes and NO assigned
2700                            addresses. When oif is specified, routing
2701                            tables are looked up with only one purpose:
2702                            to catch if destination is gatewayed, rather than
2703                            direct. Moreover, if MSG_DONTROUTE is set,
2704                            we send packet, ignoring both routing tables
2705                            and ifaddr state. --ANK
2706
2707
2708                            We could make it even if oif is unknown,
2709                            likely IPv6, but we do not.
2710                          */
2711
2712                         if (fl4->saddr == 0)
2713                                 fl4->saddr = inet_select_addr(dev_out, 0,
2714                                                               RT_SCOPE_LINK);
2715                         res.type = RTN_UNICAST;
2716                         goto make_route;
2717                 }
2718                 rth = ERR_PTR(-ENETUNREACH);
2719                 goto out;
2720         }
2721
2722         if (res.type == RTN_LOCAL) {
2723                 if (!fl4->saddr) {
2724                         if (res.fi->fib_prefsrc)
2725                                 fl4->saddr = res.fi->fib_prefsrc;
2726                         else
2727                                 fl4->saddr = fl4->daddr;
2728                 }
2729                 dev_out = net->loopback_dev;
2730                 fl4->flowi4_oif = dev_out->ifindex;
2731                 res.fi = NULL;
2732                 flags |= RTCF_LOCAL;
2733                 goto make_route;
2734         }
2735
2736 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2737         if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2738                 fib_select_multipath(&res);
2739         else
2740 #endif
2741         if (!res.prefixlen &&
2742             res.table->tb_num_default > 1 &&
2743             res.type == RTN_UNICAST && !fl4->flowi4_oif)
2744                 fib_select_default(&res);
2745
2746         if (!fl4->saddr)
2747                 fl4->saddr = FIB_RES_PREFSRC(net, res);
2748
2749         dev_out = FIB_RES_DEV(res);
2750         fl4->flowi4_oif = dev_out->ifindex;
2751
2752
2753 make_route:
2754         rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif,
2755                                tos, dev_out, flags);
2756         if (!IS_ERR(rth)) {
2757                 unsigned int hash;
2758
2759                 hash = rt_hash(orig_daddr, orig_saddr, orig_oif,
2760                                rt_genid(dev_net(dev_out)));
2761                 rth = rt_intern_hash(hash, rth, NULL, orig_oif);
2762         }
2763
2764 out:
2765         rcu_read_unlock();
2766         return rth;
2767 }
2768
2769 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
2770 {
2771         struct rtable *rth;
2772         unsigned int hash;
2773
2774         if (!rt_caching(net))
2775                 goto slow_output;
2776
2777         hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2778
2779         rcu_read_lock_bh();
2780         for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2781                 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2782                 if (rth->rt_key_dst == flp4->daddr &&
2783                     rth->rt_key_src == flp4->saddr &&
2784                     rt_is_output_route(rth) &&
2785                     rth->rt_oif == flp4->flowi4_oif &&
2786                     rth->rt_mark == flp4->flowi4_mark &&
2787                     !((rth->rt_key_tos ^ flp4->flowi4_tos) &
2788                             (IPTOS_RT_MASK | RTO_ONLINK)) &&
2789                     net_eq(dev_net(rth->dst.dev), net) &&
2790                     !rt_is_expired(rth)) {
2791                         ipv4_validate_peer(rth);
2792                         dst_use(&rth->dst, jiffies);
2793                         RT_CACHE_STAT_INC(out_hit);
2794                         rcu_read_unlock_bh();
2795                         if (!flp4->saddr)
2796                                 flp4->saddr = rth->rt_src;
2797                         if (!flp4->daddr)
2798                                 flp4->daddr = rth->rt_dst;
2799                         return rth;
2800                 }
2801                 RT_CACHE_STAT_INC(out_hlist_search);
2802         }
2803         rcu_read_unlock_bh();
2804
2805 slow_output:
2806         return ip_route_output_slow(net, flp4);
2807 }
2808 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2809
2810 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2811 {
2812         return NULL;
2813 }
2814
2815 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2816 {
2817         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2818
2819         return mtu ? : dst->dev->mtu;
2820 }
2821
2822 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2823 {
2824 }
2825
2826 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2827                                           unsigned long old)
2828 {
2829         return NULL;
2830 }
2831
2832 static struct dst_ops ipv4_dst_blackhole_ops = {
2833         .family                 =       AF_INET,
2834         .protocol               =       cpu_to_be16(ETH_P_IP),
2835         .destroy                =       ipv4_dst_destroy,
2836         .check                  =       ipv4_blackhole_dst_check,
2837         .mtu                    =       ipv4_blackhole_mtu,
2838         .default_advmss         =       ipv4_default_advmss,
2839         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2840         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
2841         .neigh_lookup           =       ipv4_neigh_lookup,
2842 };
2843
2844 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2845 {
2846         struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
2847         struct rtable *ort = (struct rtable *) dst_orig;
2848
2849         if (rt) {
2850                 struct dst_entry *new = &rt->dst;
2851
2852                 new->__use = 1;
2853                 new->input = dst_discard;
2854                 new->output = dst_discard;
2855                 dst_copy_metrics(new, &ort->dst);
2856
2857                 new->dev = ort->dst.dev;
2858                 if (new->dev)
2859                         dev_hold(new->dev);
2860
2861                 rt->rt_key_dst = ort->rt_key_dst;
2862                 rt->rt_key_src = ort->rt_key_src;
2863                 rt->rt_key_tos = ort->rt_key_tos;
2864                 rt->rt_route_iif = ort->rt_route_iif;
2865                 rt->rt_iif = ort->rt_iif;
2866                 rt->rt_oif = ort->rt_oif;
2867                 rt->rt_mark = ort->rt_mark;
2868
2869                 rt->rt_genid = rt_genid(net);
2870                 rt->rt_flags = ort->rt_flags;
2871                 rt->rt_type = ort->rt_type;
2872                 rt->rt_dst = ort->rt_dst;
2873                 rt->rt_src = ort->rt_src;
2874                 rt->rt_gateway = ort->rt_gateway;
2875                 rt_transfer_peer(rt, ort);
2876                 rt->fi = ort->fi;
2877                 if (rt->fi)
2878                         atomic_inc(&rt->fi->fib_clntref);
2879
2880                 dst_free(new);
2881         }
2882
2883         dst_release(dst_orig);
2884
2885         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2886 }
2887
2888 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2889                                     struct sock *sk)
2890 {
2891         struct rtable *rt = __ip_route_output_key(net, flp4);
2892
2893         if (IS_ERR(rt))
2894                 return rt;
2895
2896         if (flp4->flowi4_proto)
2897                 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2898                                                    flowi4_to_flowi(flp4),
2899                                                    sk, 0);
2900
2901         return rt;
2902 }
2903 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2904
2905 static int rt_fill_info(struct net *net,
2906                         struct sk_buff *skb, u32 pid, u32 seq, int event,
2907                         int nowait, unsigned int flags)
2908 {
2909         struct rtable *rt = skb_rtable(skb);
2910         struct rtmsg *r;
2911         struct nlmsghdr *nlh;
2912         unsigned long expires = 0;
2913         u32 id = 0, ts = 0, tsage = 0, error;
2914
2915         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2916         if (nlh == NULL)
2917                 return -EMSGSIZE;
2918
2919         r = nlmsg_data(nlh);
2920         r->rtm_family    = AF_INET;
2921         r->rtm_dst_len  = 32;
2922         r->rtm_src_len  = 0;
2923         r->rtm_tos      = rt->rt_key_tos;
2924         r->rtm_table    = RT_TABLE_MAIN;
2925         if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2926                 goto nla_put_failure;
2927         r->rtm_type     = rt->rt_type;
2928         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2929         r->rtm_protocol = RTPROT_UNSPEC;
2930         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2931         if (rt->rt_flags & RTCF_NOTIFY)
2932                 r->rtm_flags |= RTM_F_NOTIFY;
2933
2934         if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2935                 goto nla_put_failure;
2936         if (rt->rt_key_src) {
2937                 r->rtm_src_len = 32;
2938                 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src))
2939                         goto nla_put_failure;
2940         }
2941         if (rt->dst.dev &&
2942             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2943                 goto nla_put_failure;
2944 #ifdef CONFIG_IP_ROUTE_CLASSID
2945         if (rt->dst.tclassid &&
2946             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2947                 goto nla_put_failure;
2948 #endif
2949         if (!rt_is_input_route(rt) &&
2950             rt->rt_src != rt->rt_key_src) {
2951                 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src))
2952                         goto nla_put_failure;
2953         }
2954         if (rt->rt_dst != rt->rt_gateway &&
2955             nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2956                 goto nla_put_failure;
2957
2958         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
2959                 goto nla_put_failure;
2960
2961         if (rt->rt_mark &&
2962             nla_put_be32(skb, RTA_MARK, rt->rt_mark))
2963                 goto nla_put_failure;
2964
2965         error = rt->dst.error;
2966         if (rt_has_peer(rt)) {
2967                 const struct inet_peer *peer = rt_peer_ptr(rt);
2968                 inet_peer_refcheck(peer);
2969                 id = atomic_read(&peer->ip_id_count) & 0xffff;
2970                 if (peer->tcp_ts_stamp) {
2971                         ts = peer->tcp_ts;
2972                         tsage = get_seconds() - peer->tcp_ts_stamp;
2973                 }
2974                 expires = ACCESS_ONCE(peer->pmtu_expires);
2975                 if (expires) {
2976                         if (time_before(jiffies, expires))
2977                                 expires -= jiffies;
2978                         else
2979                                 expires = 0;
2980                 }
2981         }
2982
2983         if (rt_is_input_route(rt)) {
2984 #ifdef CONFIG_IP_MROUTE
2985                 __be32 dst = rt->rt_dst;
2986
2987                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2988                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2989                         int err = ipmr_get_route(net, skb,
2990                                                  rt->rt_src, rt->rt_dst,
2991                                                  r, nowait);
2992                         if (err <= 0) {
2993                                 if (!nowait) {
2994                                         if (err == 0)
2995                                                 return 0;
2996                                         goto nla_put_failure;
2997                                 } else {
2998                                         if (err == -EMSGSIZE)
2999                                                 goto nla_put_failure;
3000                                         error = err;
3001                                 }
3002                         }
3003                 } else
3004 #endif
3005                         if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
3006                                 goto nla_put_failure;
3007         }
3008
3009         if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage,
3010                                expires, error) < 0)
3011                 goto nla_put_failure;
3012
3013         return nlmsg_end(skb, nlh);
3014
3015 nla_put_failure:
3016         nlmsg_cancel(skb, nlh);
3017         return -EMSGSIZE;
3018 }
3019
3020 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
3021 {
3022         struct net *net = sock_net(in_skb->sk);
3023         struct rtmsg *rtm;
3024         struct nlattr *tb[RTA_MAX+1];
3025         struct rtable *rt = NULL;
3026         __be32 dst = 0;
3027         __be32 src = 0;
3028         u32 iif;
3029         int err;
3030         int mark;
3031         struct sk_buff *skb;
3032
3033         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
3034         if (err < 0)
3035                 goto errout;
3036
3037         rtm = nlmsg_data(nlh);
3038
3039         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3040         if (skb == NULL) {
3041                 err = -ENOBUFS;
3042                 goto errout;
3043         }
3044
3045         /* Reserve room for dummy headers, this skb can pass
3046            through good chunk of routing engine.
3047          */
3048         skb_reset_mac_header(skb);
3049         skb_reset_network_header(skb);
3050
3051         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
3052         ip_hdr(skb)->protocol = IPPROTO_ICMP;
3053         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
3054
3055         src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
3056         dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
3057         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3058         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3059
3060         if (iif) {
3061                 struct net_device *dev;
3062
3063                 dev = __dev_get_by_index(net, iif);
3064                 if (dev == NULL) {
3065                         err = -ENODEV;
3066                         goto errout_free;
3067                 }
3068
3069                 skb->protocol   = htons(ETH_P_IP);
3070                 skb->dev        = dev;
3071                 skb->mark       = mark;
3072                 local_bh_disable();
3073                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
3074                 local_bh_enable();
3075
3076                 rt = skb_rtable(skb);
3077                 if (err == 0 && rt->dst.error)
3078                         err = -rt->dst.error;
3079         } else {
3080                 struct flowi4 fl4 = {
3081                         .daddr = dst,
3082                         .saddr = src,
3083                         .flowi4_tos = rtm->rtm_tos,
3084                         .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
3085                         .flowi4_mark = mark,
3086                 };
3087                 rt = ip_route_output_key(net, &fl4);
3088
3089                 err = 0;
3090                 if (IS_ERR(rt))
3091                         err = PTR_ERR(rt);
3092         }
3093
3094         if (err)
3095                 goto errout_free;
3096
3097         skb_dst_set(skb, &rt->dst);
3098         if (rtm->rtm_flags & RTM_F_NOTIFY)
3099                 rt->rt_flags |= RTCF_NOTIFY;
3100
3101         err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
3102                            RTM_NEWROUTE, 0, 0);
3103         if (err <= 0)
3104                 goto errout_free;
3105
3106         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
3107 errout:
3108         return err;
3109
3110 errout_free:
3111         kfree_skb(skb);
3112         goto errout;
3113 }
3114
3115 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
3116 {
3117         struct rtable *rt;
3118         int h, s_h;
3119         int idx, s_idx;
3120         struct net *net;
3121
3122         net = sock_net(skb->sk);
3123
3124         s_h = cb->args[0];
3125         if (s_h < 0)
3126                 s_h = 0;
3127         s_idx = idx = cb->args[1];
3128         for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
3129                 if (!rt_hash_table[h].chain)
3130                         continue;
3131                 rcu_read_lock_bh();
3132                 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
3133                      rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
3134                         if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
3135                                 continue;
3136                         if (rt_is_expired(rt))
3137                                 continue;
3138                         skb_dst_set_noref(skb, &rt->dst);
3139                         if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
3140                                          cb->nlh->nlmsg_seq, RTM_NEWROUTE,
3141                                          1, NLM_F_MULTI) <= 0) {
3142                                 skb_dst_drop(skb);
3143                                 rcu_read_unlock_bh();
3144                                 goto done;
3145                         }
3146                         skb_dst_drop(skb);
3147                 }
3148                 rcu_read_unlock_bh();
3149         }
3150
3151 done:
3152         cb->args[0] = h;
3153         cb->args[1] = idx;
3154         return skb->len;
3155 }
3156
3157 void ip_rt_multicast_event(struct in_device *in_dev)
3158 {
3159         rt_cache_flush(dev_net(in_dev->dev), 0);
3160 }
3161
3162 #ifdef CONFIG_SYSCTL
3163 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
3164                                         void __user *buffer,
3165                                         size_t *lenp, loff_t *ppos)
3166 {
3167         if (write) {
3168                 int flush_delay;
3169                 ctl_table ctl;
3170                 struct net *net;
3171
3172                 memcpy(&ctl, __ctl, sizeof(ctl));
3173                 ctl.data = &flush_delay;
3174                 proc_dointvec(&ctl, write, buffer, lenp, ppos);
3175
3176                 net = (struct net *)__ctl->extra1;
3177                 rt_cache_flush(net, flush_delay);
3178                 return 0;
3179         }
3180
3181         return -EINVAL;
3182 }
3183
3184 static ctl_table ipv4_route_table[] = {
3185         {
3186                 .procname       = "gc_thresh",
3187                 .data           = &ipv4_dst_ops.gc_thresh,
3188                 .maxlen         = sizeof(int),
3189                 .mode           = 0644,
3190                 .proc_handler   = proc_dointvec,
3191         },
3192         {
3193                 .procname       = "max_size",
3194                 .data           = &ip_rt_max_size,
3195                 .maxlen         = sizeof(int),
3196                 .mode           = 0644,
3197                 .proc_handler   = proc_dointvec,
3198         },
3199         {
3200                 /*  Deprecated. Use gc_min_interval_ms */
3201
3202                 .procname       = "gc_min_interval",
3203                 .data           = &ip_rt_gc_min_interval,
3204                 .maxlen         = sizeof(int),
3205                 .mode           = 0644,
3206                 .proc_handler   = proc_dointvec_jiffies,
3207         },
3208         {
3209                 .procname       = "gc_min_interval_ms",
3210                 .data           = &ip_rt_gc_min_interval,
3211                 .maxlen         = sizeof(int),
3212                 .mode           = 0644,
3213                 .proc_handler   = proc_dointvec_ms_jiffies,
3214         },
3215         {
3216                 .procname       = "gc_timeout",
3217                 .data           = &ip_rt_gc_timeout,
3218                 .maxlen         = sizeof(int),
3219                 .mode           = 0644,
3220                 .proc_handler   = proc_dointvec_jiffies,
3221         },
3222         {
3223                 .procname       = "gc_interval",
3224                 .data           = &ip_rt_gc_interval,
3225                 .maxlen         = sizeof(int),
3226                 .mode           = 0644,
3227                 .proc_handler   = proc_dointvec_jiffies,
3228         },
3229         {
3230                 .procname       = "redirect_load",
3231                 .data           = &ip_rt_redirect_load,
3232                 .maxlen         = sizeof(int),
3233                 .mode           = 0644,
3234                 .proc_handler   = proc_dointvec,
3235         },
3236         {
3237                 .procname       = "redirect_number",
3238                 .data           = &ip_rt_redirect_number,
3239                 .maxlen         = sizeof(int),
3240                 .mode           = 0644,
3241                 .proc_handler   = proc_dointvec,
3242         },
3243         {
3244                 .procname       = "redirect_silence",
3245                 .data           = &ip_rt_redirect_silence,
3246                 .maxlen         = sizeof(int),
3247                 .mode           = 0644,
3248                 .proc_handler   = proc_dointvec,
3249         },
3250         {
3251                 .procname       = "error_cost",
3252                 .data           = &ip_rt_error_cost,
3253                 .maxlen         = sizeof(int),
3254                 .mode           = 0644,
3255                 .proc_handler   = proc_dointvec,
3256         },
3257         {
3258                 .procname       = "error_burst",
3259                 .data           = &ip_rt_error_burst,
3260                 .maxlen         = sizeof(int),
3261                 .mode           = 0644,
3262                 .proc_handler   = proc_dointvec,
3263         },
3264         {
3265                 .procname       = "gc_elasticity",
3266                 .data           = &ip_rt_gc_elasticity,
3267                 .maxlen         = sizeof(int),
3268                 .mode           = 0644,
3269                 .proc_handler   = proc_dointvec,
3270         },
3271         {
3272                 .procname       = "mtu_expires",
3273                 .data           = &ip_rt_mtu_expires,
3274                 .maxlen         = sizeof(int),
3275                 .mode           = 0644,
3276                 .proc_handler   = proc_dointvec_jiffies,
3277         },
3278         {
3279                 .procname       = "min_pmtu",
3280                 .data           = &ip_rt_min_pmtu,
3281                 .maxlen         = sizeof(int),
3282                 .mode           = 0644,
3283                 .proc_handler   = proc_dointvec,
3284         },
3285         {
3286                 .procname       = "min_adv_mss",
3287                 .data           = &ip_rt_min_advmss,
3288                 .maxlen         = sizeof(int),
3289                 .mode           = 0644,
3290                 .proc_handler   = proc_dointvec,
3291         },
3292         { }
3293 };
3294
3295 static struct ctl_table ipv4_route_flush_table[] = {
3296         {
3297                 .procname       = "flush",
3298                 .maxlen         = sizeof(int),
3299                 .mode           = 0200,
3300                 .proc_handler   = ipv4_sysctl_rtcache_flush,
3301         },
3302         { },
3303 };
3304
3305 static __net_init int sysctl_route_net_init(struct net *net)
3306 {
3307         struct ctl_table *tbl;
3308
3309         tbl = ipv4_route_flush_table;
3310         if (!net_eq(net, &init_net)) {
3311                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3312                 if (tbl == NULL)
3313                         goto err_dup;
3314         }
3315         tbl[0].extra1 = net;
3316
3317         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3318         if (net->ipv4.route_hdr == NULL)
3319                 goto err_reg;
3320         return 0;
3321
3322 err_reg:
3323         if (tbl != ipv4_route_flush_table)
3324                 kfree(tbl);
3325 err_dup:
3326         return -ENOMEM;
3327 }
3328
3329 static __net_exit void sysctl_route_net_exit(struct net *net)
3330 {
3331         struct ctl_table *tbl;
3332
3333         tbl = net->ipv4.route_hdr->ctl_table_arg;
3334         unregister_net_sysctl_table(net->ipv4.route_hdr);
3335         BUG_ON(tbl == ipv4_route_flush_table);
3336         kfree(tbl);
3337 }
3338
3339 static __net_initdata struct pernet_operations sysctl_route_ops = {
3340         .init = sysctl_route_net_init,
3341         .exit = sysctl_route_net_exit,
3342 };
3343 #endif
3344
3345 static __net_init int rt_genid_init(struct net *net)
3346 {
3347         get_random_bytes(&net->ipv4.rt_genid,
3348                          sizeof(net->ipv4.rt_genid));
3349         get_random_bytes(&net->ipv4.dev_addr_genid,
3350                          sizeof(net->ipv4.dev_addr_genid));
3351         return 0;
3352 }
3353
3354 static __net_initdata struct pernet_operations rt_genid_ops = {
3355         .init = rt_genid_init,
3356 };
3357
3358 static int __net_init ipv4_inetpeer_init(struct net *net)
3359 {
3360         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3361
3362         if (!bp)
3363                 return -ENOMEM;
3364         inet_peer_base_init(bp);
3365         net->ipv4.peers = bp;
3366         return 0;
3367 }
3368
3369 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3370 {
3371         struct inet_peer_base *bp = net->ipv4.peers;
3372
3373         net->ipv4.peers = NULL;
3374         inetpeer_invalidate_tree(bp);
3375         kfree(bp);
3376 }
3377
3378 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3379         .init   =       ipv4_inetpeer_init,
3380         .exit   =       ipv4_inetpeer_exit,
3381 };
3382
3383 #ifdef CONFIG_IP_ROUTE_CLASSID
3384 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3385 #endif /* CONFIG_IP_ROUTE_CLASSID */
3386
3387 static __initdata unsigned long rhash_entries;
3388 static int __init set_rhash_entries(char *str)
3389 {
3390         ssize_t ret;
3391
3392         if (!str)
3393                 return 0;
3394
3395         ret = kstrtoul(str, 0, &rhash_entries);
3396         if (ret)
3397                 return 0;
3398
3399         return 1;
3400 }
3401 __setup("rhash_entries=", set_rhash_entries);
3402
3403 int __init ip_rt_init(void)
3404 {
3405         int rc = 0;
3406
3407 #ifdef CONFIG_IP_ROUTE_CLASSID
3408         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3409         if (!ip_rt_acct)
3410                 panic("IP: failed to allocate ip_rt_acct\n");
3411 #endif
3412
3413         ipv4_dst_ops.kmem_cachep =
3414                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3415                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3416
3417         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3418
3419         if (dst_entries_init(&ipv4_dst_ops) < 0)
3420                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3421
3422         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3423                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3424
3425         rt_hash_table = (struct rt_hash_bucket *)
3426                 alloc_large_system_hash("IP route cache",
3427                                         sizeof(struct rt_hash_bucket),
3428                                         rhash_entries,
3429                                         (totalram_pages >= 128 * 1024) ?
3430                                         15 : 17,
3431                                         0,
3432                                         &rt_hash_log,
3433                                         &rt_hash_mask,
3434                                         0,
3435                                         rhash_entries ? 0 : 512 * 1024);
3436         memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3437         rt_hash_lock_init();
3438
3439         ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3440         ip_rt_max_size = (rt_hash_mask + 1) * 16;
3441
3442         devinet_init();
3443         ip_fib_init();
3444
3445         INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3446         expires_ljiffies = jiffies;
3447         schedule_delayed_work(&expires_work,
3448                 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3449
3450         if (ip_rt_proc_init())
3451                 pr_err("Unable to create route proc files\n");
3452 #ifdef CONFIG_XFRM
3453         xfrm_init();
3454         xfrm4_init(ip_rt_max_size);
3455 #endif
3456         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3457
3458 #ifdef CONFIG_SYSCTL
3459         register_pernet_subsys(&sysctl_route_ops);
3460 #endif
3461         register_pernet_subsys(&rt_genid_ops);
3462         register_pernet_subsys(&ipv4_inetpeer_ops);
3463         return rc;
3464 }
3465
3466 #ifdef CONFIG_SYSCTL
3467 /*
3468  * We really need to sanitize the damn ipv4 init order, then all
3469  * this nonsense will go away.
3470  */
3471 void __init ip_static_sysctl_init(void)
3472 {
3473         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3474 }
3475 #endif