sysctl net: Remove unused binary sysctl code
[linux-2.6.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 #include <linux/module.h>
66 #include <asm/uaccess.h>
67 #include <asm/system.h>
68 #include <linux/bitops.h>
69 #include <linux/types.h>
70 #include <linux/kernel.h>
71 #include <linux/mm.h>
72 #include <linux/bootmem.h>
73 #include <linux/string.h>
74 #include <linux/socket.h>
75 #include <linux/sockios.h>
76 #include <linux/errno.h>
77 #include <linux/in.h>
78 #include <linux/inet.h>
79 #include <linux/netdevice.h>
80 #include <linux/proc_fs.h>
81 #include <linux/init.h>
82 #include <linux/workqueue.h>
83 #include <linux/skbuff.h>
84 #include <linux/inetdevice.h>
85 #include <linux/igmp.h>
86 #include <linux/pkt_sched.h>
87 #include <linux/mroute.h>
88 #include <linux/netfilter_ipv4.h>
89 #include <linux/random.h>
90 #include <linux/jhash.h>
91 #include <linux/rcupdate.h>
92 #include <linux/times.h>
93 #include <net/dst.h>
94 #include <net/net_namespace.h>
95 #include <net/protocol.h>
96 #include <net/ip.h>
97 #include <net/route.h>
98 #include <net/inetpeer.h>
99 #include <net/sock.h>
100 #include <net/ip_fib.h>
101 #include <net/arp.h>
102 #include <net/tcp.h>
103 #include <net/icmp.h>
104 #include <net/xfrm.h>
105 #include <net/netevent.h>
106 #include <net/rtnetlink.h>
107 #ifdef CONFIG_SYSCTL
108 #include <linux/sysctl.h>
109 #endif
110
111 #define RT_FL_TOS(oldflp) \
112     ((u32)(oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
113
114 #define IP_MAX_MTU      0xFFF0
115
116 #define RT_GC_TIMEOUT (300*HZ)
117
118 static int ip_rt_max_size;
119 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
120 static int ip_rt_gc_interval __read_mostly      = 60 * HZ;
121 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
122 static int ip_rt_redirect_number __read_mostly  = 9;
123 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
124 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
125 static int ip_rt_error_cost __read_mostly       = HZ;
126 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
127 static int ip_rt_gc_elasticity __read_mostly    = 8;
128 static int ip_rt_mtu_expires __read_mostly      = 10 * 60 * HZ;
129 static int ip_rt_min_pmtu __read_mostly         = 512 + 20 + 20;
130 static int ip_rt_min_advmss __read_mostly       = 256;
131 static int ip_rt_secret_interval __read_mostly  = 10 * 60 * HZ;
132 static int rt_chain_length_max __read_mostly    = 20;
133
134 static struct delayed_work expires_work;
135 static unsigned long expires_ljiffies;
136
137 /*
138  *      Interface to generic destination cache.
139  */
140
141 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
142 static void              ipv4_dst_destroy(struct dst_entry *dst);
143 static void              ipv4_dst_ifdown(struct dst_entry *dst,
144                                          struct net_device *dev, int how);
145 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
146 static void              ipv4_link_failure(struct sk_buff *skb);
147 static void              ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
148 static int rt_garbage_collect(struct dst_ops *ops);
149 static void rt_emergency_hash_rebuild(struct net *net);
150
151
152 static struct dst_ops ipv4_dst_ops = {
153         .family =               AF_INET,
154         .protocol =             cpu_to_be16(ETH_P_IP),
155         .gc =                   rt_garbage_collect,
156         .check =                ipv4_dst_check,
157         .destroy =              ipv4_dst_destroy,
158         .ifdown =               ipv4_dst_ifdown,
159         .negative_advice =      ipv4_negative_advice,
160         .link_failure =         ipv4_link_failure,
161         .update_pmtu =          ip_rt_update_pmtu,
162         .local_out =            __ip_local_out,
163         .entries =              ATOMIC_INIT(0),
164 };
165
166 #define ECN_OR_COST(class)      TC_PRIO_##class
167
168 const __u8 ip_tos2prio[16] = {
169         TC_PRIO_BESTEFFORT,
170         ECN_OR_COST(FILLER),
171         TC_PRIO_BESTEFFORT,
172         ECN_OR_COST(BESTEFFORT),
173         TC_PRIO_BULK,
174         ECN_OR_COST(BULK),
175         TC_PRIO_BULK,
176         ECN_OR_COST(BULK),
177         TC_PRIO_INTERACTIVE,
178         ECN_OR_COST(INTERACTIVE),
179         TC_PRIO_INTERACTIVE,
180         ECN_OR_COST(INTERACTIVE),
181         TC_PRIO_INTERACTIVE_BULK,
182         ECN_OR_COST(INTERACTIVE_BULK),
183         TC_PRIO_INTERACTIVE_BULK,
184         ECN_OR_COST(INTERACTIVE_BULK)
185 };
186
187
188 /*
189  * Route cache.
190  */
191
192 /* The locking scheme is rather straight forward:
193  *
194  * 1) Read-Copy Update protects the buckets of the central route hash.
195  * 2) Only writers remove entries, and they hold the lock
196  *    as they look at rtable reference counts.
197  * 3) Only readers acquire references to rtable entries,
198  *    they do so with atomic increments and with the
199  *    lock held.
200  */
201
202 struct rt_hash_bucket {
203         struct rtable   *chain;
204 };
205
206 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
207         defined(CONFIG_PROVE_LOCKING)
208 /*
209  * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
210  * The size of this table is a power of two and depends on the number of CPUS.
211  * (on lockdep we have a quite big spinlock_t, so keep the size down there)
212  */
213 #ifdef CONFIG_LOCKDEP
214 # define RT_HASH_LOCK_SZ        256
215 #else
216 # if NR_CPUS >= 32
217 #  define RT_HASH_LOCK_SZ       4096
218 # elif NR_CPUS >= 16
219 #  define RT_HASH_LOCK_SZ       2048
220 # elif NR_CPUS >= 8
221 #  define RT_HASH_LOCK_SZ       1024
222 # elif NR_CPUS >= 4
223 #  define RT_HASH_LOCK_SZ       512
224 # else
225 #  define RT_HASH_LOCK_SZ       256
226 # endif
227 #endif
228
229 static spinlock_t       *rt_hash_locks;
230 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
231
232 static __init void rt_hash_lock_init(void)
233 {
234         int i;
235
236         rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
237                         GFP_KERNEL);
238         if (!rt_hash_locks)
239                 panic("IP: failed to allocate rt_hash_locks\n");
240
241         for (i = 0; i < RT_HASH_LOCK_SZ; i++)
242                 spin_lock_init(&rt_hash_locks[i]);
243 }
244 #else
245 # define rt_hash_lock_addr(slot) NULL
246
247 static inline void rt_hash_lock_init(void)
248 {
249 }
250 #endif
251
252 static struct rt_hash_bucket    *rt_hash_table __read_mostly;
253 static unsigned                 rt_hash_mask __read_mostly;
254 static unsigned int             rt_hash_log  __read_mostly;
255
256 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
257 #define RT_CACHE_STAT_INC(field) \
258         (__raw_get_cpu_var(rt_cache_stat).field++)
259
260 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
261                 int genid)
262 {
263         return jhash_3words((__force u32)(__be32)(daddr),
264                             (__force u32)(__be32)(saddr),
265                             idx, genid)
266                 & rt_hash_mask;
267 }
268
269 static inline int rt_genid(struct net *net)
270 {
271         return atomic_read(&net->ipv4.rt_genid);
272 }
273
274 #ifdef CONFIG_PROC_FS
275 struct rt_cache_iter_state {
276         struct seq_net_private p;
277         int bucket;
278         int genid;
279 };
280
281 static struct rtable *rt_cache_get_first(struct seq_file *seq)
282 {
283         struct rt_cache_iter_state *st = seq->private;
284         struct rtable *r = NULL;
285
286         for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
287                 if (!rt_hash_table[st->bucket].chain)
288                         continue;
289                 rcu_read_lock_bh();
290                 r = rcu_dereference(rt_hash_table[st->bucket].chain);
291                 while (r) {
292                         if (dev_net(r->u.dst.dev) == seq_file_net(seq) &&
293                             r->rt_genid == st->genid)
294                                 return r;
295                         r = rcu_dereference(r->u.dst.rt_next);
296                 }
297                 rcu_read_unlock_bh();
298         }
299         return r;
300 }
301
302 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
303                                           struct rtable *r)
304 {
305         struct rt_cache_iter_state *st = seq->private;
306
307         r = r->u.dst.rt_next;
308         while (!r) {
309                 rcu_read_unlock_bh();
310                 do {
311                         if (--st->bucket < 0)
312                                 return NULL;
313                 } while (!rt_hash_table[st->bucket].chain);
314                 rcu_read_lock_bh();
315                 r = rt_hash_table[st->bucket].chain;
316         }
317         return rcu_dereference(r);
318 }
319
320 static struct rtable *rt_cache_get_next(struct seq_file *seq,
321                                         struct rtable *r)
322 {
323         struct rt_cache_iter_state *st = seq->private;
324         while ((r = __rt_cache_get_next(seq, r)) != NULL) {
325                 if (dev_net(r->u.dst.dev) != seq_file_net(seq))
326                         continue;
327                 if (r->rt_genid == st->genid)
328                         break;
329         }
330         return r;
331 }
332
333 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
334 {
335         struct rtable *r = rt_cache_get_first(seq);
336
337         if (r)
338                 while (pos && (r = rt_cache_get_next(seq, r)))
339                         --pos;
340         return pos ? NULL : r;
341 }
342
343 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
344 {
345         struct rt_cache_iter_state *st = seq->private;
346         if (*pos)
347                 return rt_cache_get_idx(seq, *pos - 1);
348         st->genid = rt_genid(seq_file_net(seq));
349         return SEQ_START_TOKEN;
350 }
351
352 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
353 {
354         struct rtable *r;
355
356         if (v == SEQ_START_TOKEN)
357                 r = rt_cache_get_first(seq);
358         else
359                 r = rt_cache_get_next(seq, v);
360         ++*pos;
361         return r;
362 }
363
364 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
365 {
366         if (v && v != SEQ_START_TOKEN)
367                 rcu_read_unlock_bh();
368 }
369
370 static int rt_cache_seq_show(struct seq_file *seq, void *v)
371 {
372         if (v == SEQ_START_TOKEN)
373                 seq_printf(seq, "%-127s\n",
374                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
375                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
376                            "HHUptod\tSpecDst");
377         else {
378                 struct rtable *r = v;
379                 int len;
380
381                 seq_printf(seq, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
382                               "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
383                         r->u.dst.dev ? r->u.dst.dev->name : "*",
384                         (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
385                         r->rt_flags, atomic_read(&r->u.dst.__refcnt),
386                         r->u.dst.__use, 0, (unsigned long)r->rt_src,
387                         (dst_metric(&r->u.dst, RTAX_ADVMSS) ?
388                              (int)dst_metric(&r->u.dst, RTAX_ADVMSS) + 40 : 0),
389                         dst_metric(&r->u.dst, RTAX_WINDOW),
390                         (int)((dst_metric(&r->u.dst, RTAX_RTT) >> 3) +
391                               dst_metric(&r->u.dst, RTAX_RTTVAR)),
392                         r->fl.fl4_tos,
393                         r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
394                         r->u.dst.hh ? (r->u.dst.hh->hh_output ==
395                                        dev_queue_xmit) : 0,
396                         r->rt_spec_dst, &len);
397
398                 seq_printf(seq, "%*s\n", 127 - len, "");
399         }
400         return 0;
401 }
402
403 static const struct seq_operations rt_cache_seq_ops = {
404         .start  = rt_cache_seq_start,
405         .next   = rt_cache_seq_next,
406         .stop   = rt_cache_seq_stop,
407         .show   = rt_cache_seq_show,
408 };
409
410 static int rt_cache_seq_open(struct inode *inode, struct file *file)
411 {
412         return seq_open_net(inode, file, &rt_cache_seq_ops,
413                         sizeof(struct rt_cache_iter_state));
414 }
415
416 static const struct file_operations rt_cache_seq_fops = {
417         .owner   = THIS_MODULE,
418         .open    = rt_cache_seq_open,
419         .read    = seq_read,
420         .llseek  = seq_lseek,
421         .release = seq_release_net,
422 };
423
424
425 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
426 {
427         int cpu;
428
429         if (*pos == 0)
430                 return SEQ_START_TOKEN;
431
432         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
433                 if (!cpu_possible(cpu))
434                         continue;
435                 *pos = cpu+1;
436                 return &per_cpu(rt_cache_stat, cpu);
437         }
438         return NULL;
439 }
440
441 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
442 {
443         int cpu;
444
445         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
446                 if (!cpu_possible(cpu))
447                         continue;
448                 *pos = cpu+1;
449                 return &per_cpu(rt_cache_stat, cpu);
450         }
451         return NULL;
452
453 }
454
455 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
456 {
457
458 }
459
460 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
461 {
462         struct rt_cache_stat *st = v;
463
464         if (v == SEQ_START_TOKEN) {
465                 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");
466                 return 0;
467         }
468
469         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
470                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
471                    atomic_read(&ipv4_dst_ops.entries),
472                    st->in_hit,
473                    st->in_slow_tot,
474                    st->in_slow_mc,
475                    st->in_no_route,
476                    st->in_brd,
477                    st->in_martian_dst,
478                    st->in_martian_src,
479
480                    st->out_hit,
481                    st->out_slow_tot,
482                    st->out_slow_mc,
483
484                    st->gc_total,
485                    st->gc_ignored,
486                    st->gc_goal_miss,
487                    st->gc_dst_overflow,
488                    st->in_hlist_search,
489                    st->out_hlist_search
490                 );
491         return 0;
492 }
493
494 static const struct seq_operations rt_cpu_seq_ops = {
495         .start  = rt_cpu_seq_start,
496         .next   = rt_cpu_seq_next,
497         .stop   = rt_cpu_seq_stop,
498         .show   = rt_cpu_seq_show,
499 };
500
501
502 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
503 {
504         return seq_open(file, &rt_cpu_seq_ops);
505 }
506
507 static const struct file_operations rt_cpu_seq_fops = {
508         .owner   = THIS_MODULE,
509         .open    = rt_cpu_seq_open,
510         .read    = seq_read,
511         .llseek  = seq_lseek,
512         .release = seq_release,
513 };
514
515 #ifdef CONFIG_NET_CLS_ROUTE
516 static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
517                            int length, int *eof, void *data)
518 {
519         unsigned int i;
520
521         if ((offset & 3) || (length & 3))
522                 return -EIO;
523
524         if (offset >= sizeof(struct ip_rt_acct) * 256) {
525                 *eof = 1;
526                 return 0;
527         }
528
529         if (offset + length >= sizeof(struct ip_rt_acct) * 256) {
530                 length = sizeof(struct ip_rt_acct) * 256 - offset;
531                 *eof = 1;
532         }
533
534         offset /= sizeof(u32);
535
536         if (length > 0) {
537                 u32 *dst = (u32 *) buffer;
538
539                 *start = buffer;
540                 memset(dst, 0, length);
541
542                 for_each_possible_cpu(i) {
543                         unsigned int j;
544                         u32 *src;
545
546                         src = ((u32 *) per_cpu_ptr(ip_rt_acct, i)) + offset;
547                         for (j = 0; j < length/4; j++)
548                                 dst[j] += src[j];
549                 }
550         }
551         return length;
552 }
553 #endif
554
555 static int __net_init ip_rt_do_proc_init(struct net *net)
556 {
557         struct proc_dir_entry *pde;
558
559         pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
560                         &rt_cache_seq_fops);
561         if (!pde)
562                 goto err1;
563
564         pde = proc_create("rt_cache", S_IRUGO,
565                           net->proc_net_stat, &rt_cpu_seq_fops);
566         if (!pde)
567                 goto err2;
568
569 #ifdef CONFIG_NET_CLS_ROUTE
570         pde = create_proc_read_entry("rt_acct", 0, net->proc_net,
571                         ip_rt_acct_read, NULL);
572         if (!pde)
573                 goto err3;
574 #endif
575         return 0;
576
577 #ifdef CONFIG_NET_CLS_ROUTE
578 err3:
579         remove_proc_entry("rt_cache", net->proc_net_stat);
580 #endif
581 err2:
582         remove_proc_entry("rt_cache", net->proc_net);
583 err1:
584         return -ENOMEM;
585 }
586
587 static void __net_exit ip_rt_do_proc_exit(struct net *net)
588 {
589         remove_proc_entry("rt_cache", net->proc_net_stat);
590         remove_proc_entry("rt_cache", net->proc_net);
591         remove_proc_entry("rt_acct", net->proc_net);
592 }
593
594 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
595         .init = ip_rt_do_proc_init,
596         .exit = ip_rt_do_proc_exit,
597 };
598
599 static int __init ip_rt_proc_init(void)
600 {
601         return register_pernet_subsys(&ip_rt_proc_ops);
602 }
603
604 #else
605 static inline int ip_rt_proc_init(void)
606 {
607         return 0;
608 }
609 #endif /* CONFIG_PROC_FS */
610
611 static inline void rt_free(struct rtable *rt)
612 {
613         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
614 }
615
616 static inline void rt_drop(struct rtable *rt)
617 {
618         ip_rt_put(rt);
619         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
620 }
621
622 static inline int rt_fast_clean(struct rtable *rth)
623 {
624         /* Kill broadcast/multicast entries very aggresively, if they
625            collide in hash table with more useful entries */
626         return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
627                 rth->fl.iif && rth->u.dst.rt_next;
628 }
629
630 static inline int rt_valuable(struct rtable *rth)
631 {
632         return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
633                 rth->u.dst.expires;
634 }
635
636 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
637 {
638         unsigned long age;
639         int ret = 0;
640
641         if (atomic_read(&rth->u.dst.__refcnt))
642                 goto out;
643
644         ret = 1;
645         if (rth->u.dst.expires &&
646             time_after_eq(jiffies, rth->u.dst.expires))
647                 goto out;
648
649         age = jiffies - rth->u.dst.lastuse;
650         ret = 0;
651         if ((age <= tmo1 && !rt_fast_clean(rth)) ||
652             (age <= tmo2 && rt_valuable(rth)))
653                 goto out;
654         ret = 1;
655 out:    return ret;
656 }
657
658 /* Bits of score are:
659  * 31: very valuable
660  * 30: not quite useless
661  * 29..0: usage counter
662  */
663 static inline u32 rt_score(struct rtable *rt)
664 {
665         u32 score = jiffies - rt->u.dst.lastuse;
666
667         score = ~score & ~(3<<30);
668
669         if (rt_valuable(rt))
670                 score |= (1<<31);
671
672         if (!rt->fl.iif ||
673             !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
674                 score |= (1<<30);
675
676         return score;
677 }
678
679 static inline bool rt_caching(const struct net *net)
680 {
681         return net->ipv4.current_rt_cache_rebuild_count <=
682                 net->ipv4.sysctl_rt_cache_rebuild_count;
683 }
684
685 static inline bool compare_hash_inputs(const struct flowi *fl1,
686                                         const struct flowi *fl2)
687 {
688         return (__force u32)(((fl1->nl_u.ip4_u.daddr ^ fl2->nl_u.ip4_u.daddr) |
689                 (fl1->nl_u.ip4_u.saddr ^ fl2->nl_u.ip4_u.saddr) |
690                 (fl1->iif ^ fl2->iif)) == 0);
691 }
692
693 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
694 {
695         return ((__force u32)((fl1->nl_u.ip4_u.daddr ^ fl2->nl_u.ip4_u.daddr) |
696                 (fl1->nl_u.ip4_u.saddr ^ fl2->nl_u.ip4_u.saddr)) |
697                 (fl1->mark ^ fl2->mark) |
698                 (*(u16 *)&fl1->nl_u.ip4_u.tos ^
699                  *(u16 *)&fl2->nl_u.ip4_u.tos) |
700                 (fl1->oif ^ fl2->oif) |
701                 (fl1->iif ^ fl2->iif)) == 0;
702 }
703
704 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
705 {
706         return dev_net(rt1->u.dst.dev) == dev_net(rt2->u.dst.dev);
707 }
708
709 static inline int rt_is_expired(struct rtable *rth)
710 {
711         return rth->rt_genid != rt_genid(dev_net(rth->u.dst.dev));
712 }
713
714 /*
715  * Perform a full scan of hash table and free all entries.
716  * Can be called by a softirq or a process.
717  * In the later case, we want to be reschedule if necessary
718  */
719 static void rt_do_flush(int process_context)
720 {
721         unsigned int i;
722         struct rtable *rth, *next;
723         struct rtable * tail;
724
725         for (i = 0; i <= rt_hash_mask; i++) {
726                 if (process_context && need_resched())
727                         cond_resched();
728                 rth = rt_hash_table[i].chain;
729                 if (!rth)
730                         continue;
731
732                 spin_lock_bh(rt_hash_lock_addr(i));
733 #ifdef CONFIG_NET_NS
734                 {
735                 struct rtable ** prev, * p;
736
737                 rth = rt_hash_table[i].chain;
738
739                 /* defer releasing the head of the list after spin_unlock */
740                 for (tail = rth; tail; tail = tail->u.dst.rt_next)
741                         if (!rt_is_expired(tail))
742                                 break;
743                 if (rth != tail)
744                         rt_hash_table[i].chain = tail;
745
746                 /* call rt_free on entries after the tail requiring flush */
747                 prev = &rt_hash_table[i].chain;
748                 for (p = *prev; p; p = next) {
749                         next = p->u.dst.rt_next;
750                         if (!rt_is_expired(p)) {
751                                 prev = &p->u.dst.rt_next;
752                         } else {
753                                 *prev = next;
754                                 rt_free(p);
755                         }
756                 }
757                 }
758 #else
759                 rth = rt_hash_table[i].chain;
760                 rt_hash_table[i].chain = NULL;
761                 tail = NULL;
762 #endif
763                 spin_unlock_bh(rt_hash_lock_addr(i));
764
765                 for (; rth != tail; rth = next) {
766                         next = rth->u.dst.rt_next;
767                         rt_free(rth);
768                 }
769         }
770 }
771
772 /*
773  * While freeing expired entries, we compute average chain length
774  * and standard deviation, using fixed-point arithmetic.
775  * This to have an estimation of rt_chain_length_max
776  *  rt_chain_length_max = max(elasticity, AVG + 4*SD)
777  * We use 3 bits for frational part, and 29 (or 61) for magnitude.
778  */
779
780 #define FRACT_BITS 3
781 #define ONE (1UL << FRACT_BITS)
782
783 static void rt_check_expire(void)
784 {
785         static unsigned int rover;
786         unsigned int i = rover, goal;
787         struct rtable *rth, *aux, **rthp;
788         unsigned long samples = 0;
789         unsigned long sum = 0, sum2 = 0;
790         unsigned long delta;
791         u64 mult;
792
793         delta = jiffies - expires_ljiffies;
794         expires_ljiffies = jiffies;
795         mult = ((u64)delta) << rt_hash_log;
796         if (ip_rt_gc_timeout > 1)
797                 do_div(mult, ip_rt_gc_timeout);
798         goal = (unsigned int)mult;
799         if (goal > rt_hash_mask)
800                 goal = rt_hash_mask + 1;
801         for (; goal > 0; goal--) {
802                 unsigned long tmo = ip_rt_gc_timeout;
803                 unsigned long length;
804
805                 i = (i + 1) & rt_hash_mask;
806                 rthp = &rt_hash_table[i].chain;
807
808                 if (need_resched())
809                         cond_resched();
810
811                 samples++;
812
813                 if (*rthp == NULL)
814                         continue;
815                 length = 0;
816                 spin_lock_bh(rt_hash_lock_addr(i));
817                 while ((rth = *rthp) != NULL) {
818                         prefetch(rth->u.dst.rt_next);
819                         if (rt_is_expired(rth)) {
820                                 *rthp = rth->u.dst.rt_next;
821                                 rt_free(rth);
822                                 continue;
823                         }
824                         if (rth->u.dst.expires) {
825                                 /* Entry is expired even if it is in use */
826                                 if (time_before_eq(jiffies, rth->u.dst.expires)) {
827 nofree:
828                                         tmo >>= 1;
829                                         rthp = &rth->u.dst.rt_next;
830                                         /*
831                                          * We only count entries on
832                                          * a chain with equal hash inputs once
833                                          * so that entries for different QOS
834                                          * levels, and other non-hash input
835                                          * attributes don't unfairly skew
836                                          * the length computation
837                                          */
838                                         for (aux = rt_hash_table[i].chain;;) {
839                                                 if (aux == rth) {
840                                                         length += ONE;
841                                                         break;
842                                                 }
843                                                 if (compare_hash_inputs(&aux->fl, &rth->fl))
844                                                         break;
845                                                 aux = aux->u.dst.rt_next;
846                                         }
847                                         continue;
848                                 }
849                         } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout))
850                                 goto nofree;
851
852                         /* Cleanup aged off entries. */
853                         *rthp = rth->u.dst.rt_next;
854                         rt_free(rth);
855                 }
856                 spin_unlock_bh(rt_hash_lock_addr(i));
857                 sum += length;
858                 sum2 += length*length;
859         }
860         if (samples) {
861                 unsigned long avg = sum / samples;
862                 unsigned long sd = int_sqrt(sum2 / samples - avg*avg);
863                 rt_chain_length_max = max_t(unsigned long,
864                                         ip_rt_gc_elasticity,
865                                         (avg + 4*sd) >> FRACT_BITS);
866         }
867         rover = i;
868 }
869
870 /*
871  * rt_worker_func() is run in process context.
872  * we call rt_check_expire() to scan part of the hash table
873  */
874 static void rt_worker_func(struct work_struct *work)
875 {
876         rt_check_expire();
877         schedule_delayed_work(&expires_work, ip_rt_gc_interval);
878 }
879
880 /*
881  * Pertubation of rt_genid by a small quantity [1..256]
882  * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
883  * many times (2^24) without giving recent rt_genid.
884  * Jenkins hash is strong enough that litle changes of rt_genid are OK.
885  */
886 static void rt_cache_invalidate(struct net *net)
887 {
888         unsigned char shuffle;
889
890         get_random_bytes(&shuffle, sizeof(shuffle));
891         atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
892 }
893
894 /*
895  * delay < 0  : invalidate cache (fast : entries will be deleted later)
896  * delay >= 0 : invalidate & flush cache (can be long)
897  */
898 void rt_cache_flush(struct net *net, int delay)
899 {
900         rt_cache_invalidate(net);
901         if (delay >= 0)
902                 rt_do_flush(!in_softirq());
903 }
904
905 /*
906  * We change rt_genid and let gc do the cleanup
907  */
908 static void rt_secret_rebuild(unsigned long __net)
909 {
910         struct net *net = (struct net *)__net;
911         rt_cache_invalidate(net);
912         mod_timer(&net->ipv4.rt_secret_timer, jiffies + ip_rt_secret_interval);
913 }
914
915 static void rt_secret_rebuild_oneshot(struct net *net)
916 {
917         del_timer_sync(&net->ipv4.rt_secret_timer);
918         rt_cache_invalidate(net);
919         if (ip_rt_secret_interval) {
920                 net->ipv4.rt_secret_timer.expires += ip_rt_secret_interval;
921                 add_timer(&net->ipv4.rt_secret_timer);
922         }
923 }
924
925 static void rt_emergency_hash_rebuild(struct net *net)
926 {
927         if (net_ratelimit()) {
928                 printk(KERN_WARNING "Route hash chain too long!\n");
929                 printk(KERN_WARNING "Adjust your secret_interval!\n");
930         }
931
932         rt_secret_rebuild_oneshot(net);
933 }
934
935 /*
936    Short description of GC goals.
937
938    We want to build algorithm, which will keep routing cache
939    at some equilibrium point, when number of aged off entries
940    is kept approximately equal to newly generated ones.
941
942    Current expiration strength is variable "expire".
943    We try to adjust it dynamically, so that if networking
944    is idle expires is large enough to keep enough of warm entries,
945    and when load increases it reduces to limit cache size.
946  */
947
948 static int rt_garbage_collect(struct dst_ops *ops)
949 {
950         static unsigned long expire = RT_GC_TIMEOUT;
951         static unsigned long last_gc;
952         static int rover;
953         static int equilibrium;
954         struct rtable *rth, **rthp;
955         unsigned long now = jiffies;
956         int goal;
957
958         /*
959          * Garbage collection is pretty expensive,
960          * do not make it too frequently.
961          */
962
963         RT_CACHE_STAT_INC(gc_total);
964
965         if (now - last_gc < ip_rt_gc_min_interval &&
966             atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) {
967                 RT_CACHE_STAT_INC(gc_ignored);
968                 goto out;
969         }
970
971         /* Calculate number of entries, which we want to expire now. */
972         goal = atomic_read(&ipv4_dst_ops.entries) -
973                 (ip_rt_gc_elasticity << rt_hash_log);
974         if (goal <= 0) {
975                 if (equilibrium < ipv4_dst_ops.gc_thresh)
976                         equilibrium = ipv4_dst_ops.gc_thresh;
977                 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
978                 if (goal > 0) {
979                         equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
980                         goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
981                 }
982         } else {
983                 /* We are in dangerous area. Try to reduce cache really
984                  * aggressively.
985                  */
986                 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
987                 equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
988         }
989
990         if (now - last_gc >= ip_rt_gc_min_interval)
991                 last_gc = now;
992
993         if (goal <= 0) {
994                 equilibrium += goal;
995                 goto work_done;
996         }
997
998         do {
999                 int i, k;
1000
1001                 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
1002                         unsigned long tmo = expire;
1003
1004                         k = (k + 1) & rt_hash_mask;
1005                         rthp = &rt_hash_table[k].chain;
1006                         spin_lock_bh(rt_hash_lock_addr(k));
1007                         while ((rth = *rthp) != NULL) {
1008                                 if (!rt_is_expired(rth) &&
1009                                         !rt_may_expire(rth, tmo, expire)) {
1010                                         tmo >>= 1;
1011                                         rthp = &rth->u.dst.rt_next;
1012                                         continue;
1013                                 }
1014                                 *rthp = rth->u.dst.rt_next;
1015                                 rt_free(rth);
1016                                 goal--;
1017                         }
1018                         spin_unlock_bh(rt_hash_lock_addr(k));
1019                         if (goal <= 0)
1020                                 break;
1021                 }
1022                 rover = k;
1023
1024                 if (goal <= 0)
1025                         goto work_done;
1026
1027                 /* Goal is not achieved. We stop process if:
1028
1029                    - if expire reduced to zero. Otherwise, expire is halfed.
1030                    - if table is not full.
1031                    - if we are called from interrupt.
1032                    - jiffies check is just fallback/debug loop breaker.
1033                      We will not spin here for long time in any case.
1034                  */
1035
1036                 RT_CACHE_STAT_INC(gc_goal_miss);
1037
1038                 if (expire == 0)
1039                         break;
1040
1041                 expire >>= 1;
1042 #if RT_CACHE_DEBUG >= 2
1043                 printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
1044                                 atomic_read(&ipv4_dst_ops.entries), goal, i);
1045 #endif
1046
1047                 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
1048                         goto out;
1049         } while (!in_softirq() && time_before_eq(jiffies, now));
1050
1051         if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
1052                 goto out;
1053         if (net_ratelimit())
1054                 printk(KERN_WARNING "dst cache overflow\n");
1055         RT_CACHE_STAT_INC(gc_dst_overflow);
1056         return 1;
1057
1058 work_done:
1059         expire += ip_rt_gc_min_interval;
1060         if (expire > ip_rt_gc_timeout ||
1061             atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh)
1062                 expire = ip_rt_gc_timeout;
1063 #if RT_CACHE_DEBUG >= 2
1064         printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
1065                         atomic_read(&ipv4_dst_ops.entries), goal, rover);
1066 #endif
1067 out:    return 0;
1068 }
1069
1070 static int rt_intern_hash(unsigned hash, struct rtable *rt,
1071                           struct rtable **rp, struct sk_buff *skb)
1072 {
1073         struct rtable   *rth, **rthp;
1074         unsigned long   now;
1075         struct rtable *cand, **candp;
1076         u32             min_score;
1077         int             chain_length;
1078         int attempts = !in_softirq();
1079
1080 restart:
1081         chain_length = 0;
1082         min_score = ~(u32)0;
1083         cand = NULL;
1084         candp = NULL;
1085         now = jiffies;
1086
1087         if (!rt_caching(dev_net(rt->u.dst.dev))) {
1088                 /*
1089                  * If we're not caching, just tell the caller we
1090                  * were successful and don't touch the route.  The
1091                  * caller hold the sole reference to the cache entry, and
1092                  * it will be released when the caller is done with it.
1093                  * If we drop it here, the callers have no way to resolve routes
1094                  * when we're not caching.  Instead, just point *rp at rt, so
1095                  * the caller gets a single use out of the route
1096                  * Note that we do rt_free on this new route entry, so that
1097                  * once its refcount hits zero, we are still able to reap it
1098                  * (Thanks Alexey)
1099                  * Note also the rt_free uses call_rcu.  We don't actually
1100                  * need rcu protection here, this is just our path to get
1101                  * on the route gc list.
1102                  */
1103
1104                 if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
1105                         int err = arp_bind_neighbour(&rt->u.dst);
1106                         if (err) {
1107                                 if (net_ratelimit())
1108                                         printk(KERN_WARNING
1109                                             "Neighbour table failure & not caching routes.\n");
1110                                 rt_drop(rt);
1111                                 return err;
1112                         }
1113                 }
1114
1115                 rt_free(rt);
1116                 goto skip_hashing;
1117         }
1118
1119         rthp = &rt_hash_table[hash].chain;
1120
1121         spin_lock_bh(rt_hash_lock_addr(hash));
1122         while ((rth = *rthp) != NULL) {
1123                 if (rt_is_expired(rth)) {
1124                         *rthp = rth->u.dst.rt_next;
1125                         rt_free(rth);
1126                         continue;
1127                 }
1128                 if (compare_keys(&rth->fl, &rt->fl) && compare_netns(rth, rt)) {
1129                         /* Put it first */
1130                         *rthp = rth->u.dst.rt_next;
1131                         /*
1132                          * Since lookup is lockfree, the deletion
1133                          * must be visible to another weakly ordered CPU before
1134                          * the insertion at the start of the hash chain.
1135                          */
1136                         rcu_assign_pointer(rth->u.dst.rt_next,
1137                                            rt_hash_table[hash].chain);
1138                         /*
1139                          * Since lookup is lockfree, the update writes
1140                          * must be ordered for consistency on SMP.
1141                          */
1142                         rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1143
1144                         dst_use(&rth->u.dst, now);
1145                         spin_unlock_bh(rt_hash_lock_addr(hash));
1146
1147                         rt_drop(rt);
1148                         if (rp)
1149                                 *rp = rth;
1150                         else
1151                                 skb_dst_set(skb, &rth->u.dst);
1152                         return 0;
1153                 }
1154
1155                 if (!atomic_read(&rth->u.dst.__refcnt)) {
1156                         u32 score = rt_score(rth);
1157
1158                         if (score <= min_score) {
1159                                 cand = rth;
1160                                 candp = rthp;
1161                                 min_score = score;
1162                         }
1163                 }
1164
1165                 chain_length++;
1166
1167                 rthp = &rth->u.dst.rt_next;
1168         }
1169
1170         if (cand) {
1171                 /* ip_rt_gc_elasticity used to be average length of chain
1172                  * length, when exceeded gc becomes really aggressive.
1173                  *
1174                  * The second limit is less certain. At the moment it allows
1175                  * only 2 entries per bucket. We will see.
1176                  */
1177                 if (chain_length > ip_rt_gc_elasticity) {
1178                         *candp = cand->u.dst.rt_next;
1179                         rt_free(cand);
1180                 }
1181         } else {
1182                 if (chain_length > rt_chain_length_max) {
1183                         struct net *net = dev_net(rt->u.dst.dev);
1184                         int num = ++net->ipv4.current_rt_cache_rebuild_count;
1185                         if (!rt_caching(dev_net(rt->u.dst.dev))) {
1186                                 printk(KERN_WARNING "%s: %d rebuilds is over limit, route caching disabled\n",
1187                                         rt->u.dst.dev->name, num);
1188                         }
1189                         rt_emergency_hash_rebuild(dev_net(rt->u.dst.dev));
1190                 }
1191         }
1192
1193         /* Try to bind route to arp only if it is output
1194            route or unicast forwarding path.
1195          */
1196         if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
1197                 int err = arp_bind_neighbour(&rt->u.dst);
1198                 if (err) {
1199                         spin_unlock_bh(rt_hash_lock_addr(hash));
1200
1201                         if (err != -ENOBUFS) {
1202                                 rt_drop(rt);
1203                                 return err;
1204                         }
1205
1206                         /* Neighbour tables are full and nothing
1207                            can be released. Try to shrink route cache,
1208                            it is most likely it holds some neighbour records.
1209                          */
1210                         if (attempts-- > 0) {
1211                                 int saved_elasticity = ip_rt_gc_elasticity;
1212                                 int saved_int = ip_rt_gc_min_interval;
1213                                 ip_rt_gc_elasticity     = 1;
1214                                 ip_rt_gc_min_interval   = 0;
1215                                 rt_garbage_collect(&ipv4_dst_ops);
1216                                 ip_rt_gc_min_interval   = saved_int;
1217                                 ip_rt_gc_elasticity     = saved_elasticity;
1218                                 goto restart;
1219                         }
1220
1221                         if (net_ratelimit())
1222                                 printk(KERN_WARNING "Neighbour table overflow.\n");
1223                         rt_drop(rt);
1224                         return -ENOBUFS;
1225                 }
1226         }
1227
1228         rt->u.dst.rt_next = rt_hash_table[hash].chain;
1229
1230 #if RT_CACHE_DEBUG >= 2
1231         if (rt->u.dst.rt_next) {
1232                 struct rtable *trt;
1233                 printk(KERN_DEBUG "rt_cache @%02x: %pI4",
1234                        hash, &rt->rt_dst);
1235                 for (trt = rt->u.dst.rt_next; trt; trt = trt->u.dst.rt_next)
1236                         printk(" . %pI4", &trt->rt_dst);
1237                 printk("\n");
1238         }
1239 #endif
1240         /*
1241          * Since lookup is lockfree, we must make sure
1242          * previous writes to rt are comitted to memory
1243          * before making rt visible to other CPUS.
1244          */
1245         rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1246
1247         spin_unlock_bh(rt_hash_lock_addr(hash));
1248
1249 skip_hashing:
1250         if (rp)
1251                 *rp = rt;
1252         else
1253                 skb_dst_set(skb, &rt->u.dst);
1254         return 0;
1255 }
1256
1257 void rt_bind_peer(struct rtable *rt, int create)
1258 {
1259         static DEFINE_SPINLOCK(rt_peer_lock);
1260         struct inet_peer *peer;
1261
1262         peer = inet_getpeer(rt->rt_dst, create);
1263
1264         spin_lock_bh(&rt_peer_lock);
1265         if (rt->peer == NULL) {
1266                 rt->peer = peer;
1267                 peer = NULL;
1268         }
1269         spin_unlock_bh(&rt_peer_lock);
1270         if (peer)
1271                 inet_putpeer(peer);
1272 }
1273
1274 /*
1275  * Peer allocation may fail only in serious out-of-memory conditions.  However
1276  * we still can generate some output.
1277  * Random ID selection looks a bit dangerous because we have no chances to
1278  * select ID being unique in a reasonable period of time.
1279  * But broken packet identifier may be better than no packet at all.
1280  */
1281 static void ip_select_fb_ident(struct iphdr *iph)
1282 {
1283         static DEFINE_SPINLOCK(ip_fb_id_lock);
1284         static u32 ip_fallback_id;
1285         u32 salt;
1286
1287         spin_lock_bh(&ip_fb_id_lock);
1288         salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1289         iph->id = htons(salt & 0xFFFF);
1290         ip_fallback_id = salt;
1291         spin_unlock_bh(&ip_fb_id_lock);
1292 }
1293
1294 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1295 {
1296         struct rtable *rt = (struct rtable *) dst;
1297
1298         if (rt) {
1299                 if (rt->peer == NULL)
1300                         rt_bind_peer(rt, 1);
1301
1302                 /* If peer is attached to destination, it is never detached,
1303                    so that we need not to grab a lock to dereference it.
1304                  */
1305                 if (rt->peer) {
1306                         iph->id = htons(inet_getid(rt->peer, more));
1307                         return;
1308                 }
1309         } else
1310                 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1311                        __builtin_return_address(0));
1312
1313         ip_select_fb_ident(iph);
1314 }
1315
1316 static void rt_del(unsigned hash, struct rtable *rt)
1317 {
1318         struct rtable **rthp, *aux;
1319
1320         rthp = &rt_hash_table[hash].chain;
1321         spin_lock_bh(rt_hash_lock_addr(hash));
1322         ip_rt_put(rt);
1323         while ((aux = *rthp) != NULL) {
1324                 if (aux == rt || rt_is_expired(aux)) {
1325                         *rthp = aux->u.dst.rt_next;
1326                         rt_free(aux);
1327                         continue;
1328                 }
1329                 rthp = &aux->u.dst.rt_next;
1330         }
1331         spin_unlock_bh(rt_hash_lock_addr(hash));
1332 }
1333
1334 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1335                     __be32 saddr, struct net_device *dev)
1336 {
1337         int i, k;
1338         struct in_device *in_dev = in_dev_get(dev);
1339         struct rtable *rth, **rthp;
1340         __be32  skeys[2] = { saddr, 0 };
1341         int  ikeys[2] = { dev->ifindex, 0 };
1342         struct netevent_redirect netevent;
1343         struct net *net;
1344
1345         if (!in_dev)
1346                 return;
1347
1348         net = dev_net(dev);
1349         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
1350             || ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw)
1351             || ipv4_is_zeronet(new_gw))
1352                 goto reject_redirect;
1353
1354         if (!rt_caching(net))
1355                 goto reject_redirect;
1356
1357         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1358                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1359                         goto reject_redirect;
1360                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1361                         goto reject_redirect;
1362         } else {
1363                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1364                         goto reject_redirect;
1365         }
1366
1367         for (i = 0; i < 2; i++) {
1368                 for (k = 0; k < 2; k++) {
1369                         unsigned hash = rt_hash(daddr, skeys[i], ikeys[k],
1370                                                 rt_genid(net));
1371
1372                         rthp=&rt_hash_table[hash].chain;
1373
1374                         rcu_read_lock();
1375                         while ((rth = rcu_dereference(*rthp)) != NULL) {
1376                                 struct rtable *rt;
1377
1378                                 if (rth->fl.fl4_dst != daddr ||
1379                                     rth->fl.fl4_src != skeys[i] ||
1380                                     rth->fl.oif != ikeys[k] ||
1381                                     rth->fl.iif != 0 ||
1382                                     rt_is_expired(rth) ||
1383                                     !net_eq(dev_net(rth->u.dst.dev), net)) {
1384                                         rthp = &rth->u.dst.rt_next;
1385                                         continue;
1386                                 }
1387
1388                                 if (rth->rt_dst != daddr ||
1389                                     rth->rt_src != saddr ||
1390                                     rth->u.dst.error ||
1391                                     rth->rt_gateway != old_gw ||
1392                                     rth->u.dst.dev != dev)
1393                                         break;
1394
1395                                 dst_hold(&rth->u.dst);
1396                                 rcu_read_unlock();
1397
1398                                 rt = dst_alloc(&ipv4_dst_ops);
1399                                 if (rt == NULL) {
1400                                         ip_rt_put(rth);
1401                                         in_dev_put(in_dev);
1402                                         return;
1403                                 }
1404
1405                                 /* Copy all the information. */
1406                                 *rt = *rth;
1407                                 rt->u.dst.__use         = 1;
1408                                 atomic_set(&rt->u.dst.__refcnt, 1);
1409                                 rt->u.dst.child         = NULL;
1410                                 if (rt->u.dst.dev)
1411                                         dev_hold(rt->u.dst.dev);
1412                                 if (rt->idev)
1413                                         in_dev_hold(rt->idev);
1414                                 rt->u.dst.obsolete      = 0;
1415                                 rt->u.dst.lastuse       = jiffies;
1416                                 rt->u.dst.path          = &rt->u.dst;
1417                                 rt->u.dst.neighbour     = NULL;
1418                                 rt->u.dst.hh            = NULL;
1419 #ifdef CONFIG_XFRM
1420                                 rt->u.dst.xfrm          = NULL;
1421 #endif
1422                                 rt->rt_genid            = rt_genid(net);
1423                                 rt->rt_flags            |= RTCF_REDIRECTED;
1424
1425                                 /* Gateway is different ... */
1426                                 rt->rt_gateway          = new_gw;
1427
1428                                 /* Redirect received -> path was valid */
1429                                 dst_confirm(&rth->u.dst);
1430
1431                                 if (rt->peer)
1432                                         atomic_inc(&rt->peer->refcnt);
1433
1434                                 if (arp_bind_neighbour(&rt->u.dst) ||
1435                                     !(rt->u.dst.neighbour->nud_state &
1436                                             NUD_VALID)) {
1437                                         if (rt->u.dst.neighbour)
1438                                                 neigh_event_send(rt->u.dst.neighbour, NULL);
1439                                         ip_rt_put(rth);
1440                                         rt_drop(rt);
1441                                         goto do_next;
1442                                 }
1443
1444                                 netevent.old = &rth->u.dst;
1445                                 netevent.new = &rt->u.dst;
1446                                 call_netevent_notifiers(NETEVENT_REDIRECT,
1447                                                         &netevent);
1448
1449                                 rt_del(hash, rth);
1450                                 if (!rt_intern_hash(hash, rt, &rt, NULL))
1451                                         ip_rt_put(rt);
1452                                 goto do_next;
1453                         }
1454                         rcu_read_unlock();
1455                 do_next:
1456                         ;
1457                 }
1458         }
1459         in_dev_put(in_dev);
1460         return;
1461
1462 reject_redirect:
1463 #ifdef CONFIG_IP_ROUTE_VERBOSE
1464         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1465                 printk(KERN_INFO "Redirect from %pI4 on %s about %pI4 ignored.\n"
1466                         "  Advised path = %pI4 -> %pI4\n",
1467                        &old_gw, dev->name, &new_gw,
1468                        &saddr, &daddr);
1469 #endif
1470         in_dev_put(in_dev);
1471 }
1472
1473 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1474 {
1475         struct rtable *rt = (struct rtable *)dst;
1476         struct dst_entry *ret = dst;
1477
1478         if (rt) {
1479                 if (dst->obsolete) {
1480                         ip_rt_put(rt);
1481                         ret = NULL;
1482                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
1483                            rt->u.dst.expires) {
1484                         unsigned hash = rt_hash(rt->fl.fl4_dst, rt->fl.fl4_src,
1485                                                 rt->fl.oif,
1486                                                 rt_genid(dev_net(dst->dev)));
1487 #if RT_CACHE_DEBUG >= 1
1488                         printk(KERN_DEBUG "ipv4_negative_advice: redirect to %pI4/%02x dropped\n",
1489                                 &rt->rt_dst, rt->fl.fl4_tos);
1490 #endif
1491                         rt_del(hash, rt);
1492                         ret = NULL;
1493                 }
1494         }
1495         return ret;
1496 }
1497
1498 /*
1499  * Algorithm:
1500  *      1. The first ip_rt_redirect_number redirects are sent
1501  *         with exponential backoff, then we stop sending them at all,
1502  *         assuming that the host ignores our redirects.
1503  *      2. If we did not see packets requiring redirects
1504  *         during ip_rt_redirect_silence, we assume that the host
1505  *         forgot redirected route and start to send redirects again.
1506  *
1507  * This algorithm is much cheaper and more intelligent than dumb load limiting
1508  * in icmp.c.
1509  *
1510  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1511  * and "frag. need" (breaks PMTU discovery) in icmp.c.
1512  */
1513
1514 void ip_rt_send_redirect(struct sk_buff *skb)
1515 {
1516         struct rtable *rt = skb_rtable(skb);
1517         struct in_device *in_dev;
1518         int log_martians;
1519
1520         rcu_read_lock();
1521         in_dev = __in_dev_get_rcu(rt->u.dst.dev);
1522         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1523                 rcu_read_unlock();
1524                 return;
1525         }
1526         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1527         rcu_read_unlock();
1528
1529         /* No redirected packets during ip_rt_redirect_silence;
1530          * reset the algorithm.
1531          */
1532         if (time_after(jiffies, rt->u.dst.rate_last + ip_rt_redirect_silence))
1533                 rt->u.dst.rate_tokens = 0;
1534
1535         /* Too many ignored redirects; do not send anything
1536          * set u.dst.rate_last to the last seen redirected packet.
1537          */
1538         if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) {
1539                 rt->u.dst.rate_last = jiffies;
1540                 return;
1541         }
1542
1543         /* Check for load limit; set rate_last to the latest sent
1544          * redirect.
1545          */
1546         if (rt->u.dst.rate_tokens == 0 ||
1547             time_after(jiffies,
1548                        (rt->u.dst.rate_last +
1549                         (ip_rt_redirect_load << rt->u.dst.rate_tokens)))) {
1550                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1551                 rt->u.dst.rate_last = jiffies;
1552                 ++rt->u.dst.rate_tokens;
1553 #ifdef CONFIG_IP_ROUTE_VERBOSE
1554                 if (log_martians &&
1555                     rt->u.dst.rate_tokens == ip_rt_redirect_number &&
1556                     net_ratelimit())
1557                         printk(KERN_WARNING "host %pI4/if%d ignores redirects for %pI4 to %pI4.\n",
1558                                 &rt->rt_src, rt->rt_iif,
1559                                 &rt->rt_dst, &rt->rt_gateway);
1560 #endif
1561         }
1562 }
1563
1564 static int ip_error(struct sk_buff *skb)
1565 {
1566         struct rtable *rt = skb_rtable(skb);
1567         unsigned long now;
1568         int code;
1569
1570         switch (rt->u.dst.error) {
1571                 case EINVAL:
1572                 default:
1573                         goto out;
1574                 case EHOSTUNREACH:
1575                         code = ICMP_HOST_UNREACH;
1576                         break;
1577                 case ENETUNREACH:
1578                         code = ICMP_NET_UNREACH;
1579                         IP_INC_STATS_BH(dev_net(rt->u.dst.dev),
1580                                         IPSTATS_MIB_INNOROUTES);
1581                         break;
1582                 case EACCES:
1583                         code = ICMP_PKT_FILTERED;
1584                         break;
1585         }
1586
1587         now = jiffies;
1588         rt->u.dst.rate_tokens += now - rt->u.dst.rate_last;
1589         if (rt->u.dst.rate_tokens > ip_rt_error_burst)
1590                 rt->u.dst.rate_tokens = ip_rt_error_burst;
1591         rt->u.dst.rate_last = now;
1592         if (rt->u.dst.rate_tokens >= ip_rt_error_cost) {
1593                 rt->u.dst.rate_tokens -= ip_rt_error_cost;
1594                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1595         }
1596
1597 out:    kfree_skb(skb);
1598         return 0;
1599 }
1600
1601 /*
1602  *      The last two values are not from the RFC but
1603  *      are needed for AMPRnet AX.25 paths.
1604  */
1605
1606 static const unsigned short mtu_plateau[] =
1607 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1608
1609 static inline unsigned short guess_mtu(unsigned short old_mtu)
1610 {
1611         int i;
1612
1613         for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1614                 if (old_mtu > mtu_plateau[i])
1615                         return mtu_plateau[i];
1616         return 68;
1617 }
1618
1619 unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
1620                                  unsigned short new_mtu,
1621                                  struct net_device *dev)
1622 {
1623         int i, k;
1624         unsigned short old_mtu = ntohs(iph->tot_len);
1625         struct rtable *rth;
1626         int  ikeys[2] = { dev->ifindex, 0 };
1627         __be32  skeys[2] = { iph->saddr, 0, };
1628         __be32  daddr = iph->daddr;
1629         unsigned short est_mtu = 0;
1630
1631         if (ipv4_config.no_pmtu_disc)
1632                 return 0;
1633
1634         for (k = 0; k < 2; k++) {
1635                 for (i = 0; i < 2; i++) {
1636                         unsigned hash = rt_hash(daddr, skeys[i], ikeys[k],
1637                                                 rt_genid(net));
1638
1639                         rcu_read_lock();
1640                         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
1641                              rth = rcu_dereference(rth->u.dst.rt_next)) {
1642                                 unsigned short mtu = new_mtu;
1643
1644                                 if (rth->fl.fl4_dst != daddr ||
1645                                     rth->fl.fl4_src != skeys[i] ||
1646                                     rth->rt_dst != daddr ||
1647                                     rth->rt_src != iph->saddr ||
1648                                     rth->fl.oif != ikeys[k] ||
1649                                     rth->fl.iif != 0 ||
1650                                     dst_metric_locked(&rth->u.dst, RTAX_MTU) ||
1651                                     !net_eq(dev_net(rth->u.dst.dev), net) ||
1652                                     rt_is_expired(rth))
1653                                         continue;
1654
1655                                 if (new_mtu < 68 || new_mtu >= old_mtu) {
1656
1657                                         /* BSD 4.2 compatibility hack :-( */
1658                                         if (mtu == 0 &&
1659                                             old_mtu >= dst_mtu(&rth->u.dst) &&
1660                                             old_mtu >= 68 + (iph->ihl << 2))
1661                                                 old_mtu -= iph->ihl << 2;
1662
1663                                         mtu = guess_mtu(old_mtu);
1664                                 }
1665                                 if (mtu <= dst_mtu(&rth->u.dst)) {
1666                                         if (mtu < dst_mtu(&rth->u.dst)) {
1667                                                 dst_confirm(&rth->u.dst);
1668                                                 if (mtu < ip_rt_min_pmtu) {
1669                                                         mtu = ip_rt_min_pmtu;
1670                                                         rth->u.dst.metrics[RTAX_LOCK-1] |=
1671                                                                 (1 << RTAX_MTU);
1672                                                 }
1673                                                 rth->u.dst.metrics[RTAX_MTU-1] = mtu;
1674                                                 dst_set_expires(&rth->u.dst,
1675                                                         ip_rt_mtu_expires);
1676                                         }
1677                                         est_mtu = mtu;
1678                                 }
1679                         }
1680                         rcu_read_unlock();
1681                 }
1682         }
1683         return est_mtu ? : new_mtu;
1684 }
1685
1686 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1687 {
1688         if (dst_mtu(dst) > mtu && mtu >= 68 &&
1689             !(dst_metric_locked(dst, RTAX_MTU))) {
1690                 if (mtu < ip_rt_min_pmtu) {
1691                         mtu = ip_rt_min_pmtu;
1692                         dst->metrics[RTAX_LOCK-1] |= (1 << RTAX_MTU);
1693                 }
1694                 dst->metrics[RTAX_MTU-1] = mtu;
1695                 dst_set_expires(dst, ip_rt_mtu_expires);
1696                 call_netevent_notifiers(NETEVENT_PMTU_UPDATE, dst);
1697         }
1698 }
1699
1700 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1701 {
1702         return NULL;
1703 }
1704
1705 static void ipv4_dst_destroy(struct dst_entry *dst)
1706 {
1707         struct rtable *rt = (struct rtable *) dst;
1708         struct inet_peer *peer = rt->peer;
1709         struct in_device *idev = rt->idev;
1710
1711         if (peer) {
1712                 rt->peer = NULL;
1713                 inet_putpeer(peer);
1714         }
1715
1716         if (idev) {
1717                 rt->idev = NULL;
1718                 in_dev_put(idev);
1719         }
1720 }
1721
1722 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
1723                             int how)
1724 {
1725         struct rtable *rt = (struct rtable *) dst;
1726         struct in_device *idev = rt->idev;
1727         if (dev != dev_net(dev)->loopback_dev && idev && idev->dev == dev) {
1728                 struct in_device *loopback_idev =
1729                         in_dev_get(dev_net(dev)->loopback_dev);
1730                 if (loopback_idev) {
1731                         rt->idev = loopback_idev;
1732                         in_dev_put(idev);
1733                 }
1734         }
1735 }
1736
1737 static void ipv4_link_failure(struct sk_buff *skb)
1738 {
1739         struct rtable *rt;
1740
1741         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1742
1743         rt = skb_rtable(skb);
1744         if (rt)
1745                 dst_set_expires(&rt->u.dst, 0);
1746 }
1747
1748 static int ip_rt_bug(struct sk_buff *skb)
1749 {
1750         printk(KERN_DEBUG "ip_rt_bug: %pI4 -> %pI4, %s\n",
1751                 &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1752                 skb->dev ? skb->dev->name : "?");
1753         kfree_skb(skb);
1754         return 0;
1755 }
1756
1757 /*
1758    We do not cache source address of outgoing interface,
1759    because it is used only by IP RR, TS and SRR options,
1760    so that it out of fast path.
1761
1762    BTW remember: "addr" is allowed to be not aligned
1763    in IP options!
1764  */
1765
1766 void ip_rt_get_source(u8 *addr, struct rtable *rt)
1767 {
1768         __be32 src;
1769         struct fib_result res;
1770
1771         if (rt->fl.iif == 0)
1772                 src = rt->rt_src;
1773         else if (fib_lookup(dev_net(rt->u.dst.dev), &rt->fl, &res) == 0) {
1774                 src = FIB_RES_PREFSRC(res);
1775                 fib_res_put(&res);
1776         } else
1777                 src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway,
1778                                         RT_SCOPE_UNIVERSE);
1779         memcpy(addr, &src, 4);
1780 }
1781
1782 #ifdef CONFIG_NET_CLS_ROUTE
1783 static void set_class_tag(struct rtable *rt, u32 tag)
1784 {
1785         if (!(rt->u.dst.tclassid & 0xFFFF))
1786                 rt->u.dst.tclassid |= tag & 0xFFFF;
1787         if (!(rt->u.dst.tclassid & 0xFFFF0000))
1788                 rt->u.dst.tclassid |= tag & 0xFFFF0000;
1789 }
1790 #endif
1791
1792 static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
1793 {
1794         struct fib_info *fi = res->fi;
1795
1796         if (fi) {
1797                 if (FIB_RES_GW(*res) &&
1798                     FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1799                         rt->rt_gateway = FIB_RES_GW(*res);
1800                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
1801                        sizeof(rt->u.dst.metrics));
1802                 if (fi->fib_mtu == 0) {
1803                         rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
1804                         if (dst_metric_locked(&rt->u.dst, RTAX_MTU) &&
1805                             rt->rt_gateway != rt->rt_dst &&
1806                             rt->u.dst.dev->mtu > 576)
1807                                 rt->u.dst.metrics[RTAX_MTU-1] = 576;
1808                 }
1809 #ifdef CONFIG_NET_CLS_ROUTE
1810                 rt->u.dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1811 #endif
1812         } else
1813                 rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu;
1814
1815         if (dst_metric(&rt->u.dst, RTAX_HOPLIMIT) == 0)
1816                 rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl;
1817         if (dst_mtu(&rt->u.dst) > IP_MAX_MTU)
1818                 rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU;
1819         if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0)
1820                 rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40,
1821                                        ip_rt_min_advmss);
1822         if (dst_metric(&rt->u.dst, RTAX_ADVMSS) > 65535 - 40)
1823                 rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40;
1824
1825 #ifdef CONFIG_NET_CLS_ROUTE
1826 #ifdef CONFIG_IP_MULTIPLE_TABLES
1827         set_class_tag(rt, fib_rules_tclass(res));
1828 #endif
1829         set_class_tag(rt, itag);
1830 #endif
1831         rt->rt_type = res->type;
1832 }
1833
1834 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1835                                 u8 tos, struct net_device *dev, int our)
1836 {
1837         unsigned hash;
1838         struct rtable *rth;
1839         __be32 spec_dst;
1840         struct in_device *in_dev = in_dev_get(dev);
1841         u32 itag = 0;
1842
1843         /* Primary sanity checks. */
1844
1845         if (in_dev == NULL)
1846                 return -EINVAL;
1847
1848         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1849             ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
1850                 goto e_inval;
1851
1852         if (ipv4_is_zeronet(saddr)) {
1853                 if (!ipv4_is_local_multicast(daddr))
1854                         goto e_inval;
1855                 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1856         } else if (fib_validate_source(saddr, 0, tos, 0,
1857                                         dev, &spec_dst, &itag, 0) < 0)
1858                 goto e_inval;
1859
1860         rth = dst_alloc(&ipv4_dst_ops);
1861         if (!rth)
1862                 goto e_nobufs;
1863
1864         rth->u.dst.output= ip_rt_bug;
1865
1866         atomic_set(&rth->u.dst.__refcnt, 1);
1867         rth->u.dst.flags= DST_HOST;
1868         if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
1869                 rth->u.dst.flags |= DST_NOPOLICY;
1870         rth->fl.fl4_dst = daddr;
1871         rth->rt_dst     = daddr;
1872         rth->fl.fl4_tos = tos;
1873         rth->fl.mark    = skb->mark;
1874         rth->fl.fl4_src = saddr;
1875         rth->rt_src     = saddr;
1876 #ifdef CONFIG_NET_CLS_ROUTE
1877         rth->u.dst.tclassid = itag;
1878 #endif
1879         rth->rt_iif     =
1880         rth->fl.iif     = dev->ifindex;
1881         rth->u.dst.dev  = init_net.loopback_dev;
1882         dev_hold(rth->u.dst.dev);
1883         rth->idev       = in_dev_get(rth->u.dst.dev);
1884         rth->fl.oif     = 0;
1885         rth->rt_gateway = daddr;
1886         rth->rt_spec_dst= spec_dst;
1887         rth->rt_genid   = rt_genid(dev_net(dev));
1888         rth->rt_flags   = RTCF_MULTICAST;
1889         rth->rt_type    = RTN_MULTICAST;
1890         if (our) {
1891                 rth->u.dst.input= ip_local_deliver;
1892                 rth->rt_flags |= RTCF_LOCAL;
1893         }
1894
1895 #ifdef CONFIG_IP_MROUTE
1896         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1897                 rth->u.dst.input = ip_mr_input;
1898 #endif
1899         RT_CACHE_STAT_INC(in_slow_mc);
1900
1901         in_dev_put(in_dev);
1902         hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
1903         return rt_intern_hash(hash, rth, NULL, skb);
1904
1905 e_nobufs:
1906         in_dev_put(in_dev);
1907         return -ENOBUFS;
1908
1909 e_inval:
1910         in_dev_put(in_dev);
1911         return -EINVAL;
1912 }
1913
1914
1915 static void ip_handle_martian_source(struct net_device *dev,
1916                                      struct in_device *in_dev,
1917                                      struct sk_buff *skb,
1918                                      __be32 daddr,
1919                                      __be32 saddr)
1920 {
1921         RT_CACHE_STAT_INC(in_martian_src);
1922 #ifdef CONFIG_IP_ROUTE_VERBOSE
1923         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1924                 /*
1925                  *      RFC1812 recommendation, if source is martian,
1926                  *      the only hint is MAC header.
1927                  */
1928                 printk(KERN_WARNING "martian source %pI4 from %pI4, on dev %s\n",
1929                         &daddr, &saddr, dev->name);
1930                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1931                         int i;
1932                         const unsigned char *p = skb_mac_header(skb);
1933                         printk(KERN_WARNING "ll header: ");
1934                         for (i = 0; i < dev->hard_header_len; i++, p++) {
1935                                 printk("%02x", *p);
1936                                 if (i < (dev->hard_header_len - 1))
1937                                         printk(":");
1938                         }
1939                         printk("\n");
1940                 }
1941         }
1942 #endif
1943 }
1944
1945 static int __mkroute_input(struct sk_buff *skb,
1946                            struct fib_result *res,
1947                            struct in_device *in_dev,
1948                            __be32 daddr, __be32 saddr, u32 tos,
1949                            struct rtable **result)
1950 {
1951
1952         struct rtable *rth;
1953         int err;
1954         struct in_device *out_dev;
1955         unsigned flags = 0;
1956         __be32 spec_dst;
1957         u32 itag;
1958
1959         /* get a working reference to the output device */
1960         out_dev = in_dev_get(FIB_RES_DEV(*res));
1961         if (out_dev == NULL) {
1962                 if (net_ratelimit())
1963                         printk(KERN_CRIT "Bug in ip_route_input" \
1964                                "_slow(). Please, report\n");
1965                 return -EINVAL;
1966         }
1967
1968
1969         err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
1970                                   in_dev->dev, &spec_dst, &itag, skb->mark);
1971         if (err < 0) {
1972                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1973                                          saddr);
1974
1975                 err = -EINVAL;
1976                 goto cleanup;
1977         }
1978
1979         if (err)
1980                 flags |= RTCF_DIRECTSRC;
1981
1982         if (out_dev == in_dev && err &&
1983             (IN_DEV_SHARED_MEDIA(out_dev) ||
1984              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1985                 flags |= RTCF_DOREDIRECT;
1986
1987         if (skb->protocol != htons(ETH_P_IP)) {
1988                 /* Not IP (i.e. ARP). Do not create route, if it is
1989                  * invalid for proxy arp. DNAT routes are always valid.
1990                  */
1991                 if (out_dev == in_dev) {
1992                         err = -EINVAL;
1993                         goto cleanup;
1994                 }
1995         }
1996
1997
1998         rth = dst_alloc(&ipv4_dst_ops);
1999         if (!rth) {
2000                 err = -ENOBUFS;
2001                 goto cleanup;
2002         }
2003
2004         atomic_set(&rth->u.dst.__refcnt, 1);
2005         rth->u.dst.flags= DST_HOST;
2006         if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
2007                 rth->u.dst.flags |= DST_NOPOLICY;
2008         if (IN_DEV_CONF_GET(out_dev, NOXFRM))
2009                 rth->u.dst.flags |= DST_NOXFRM;
2010         rth->fl.fl4_dst = daddr;
2011         rth->rt_dst     = daddr;
2012         rth->fl.fl4_tos = tos;
2013         rth->fl.mark    = skb->mark;
2014         rth->fl.fl4_src = saddr;
2015         rth->rt_src     = saddr;
2016         rth->rt_gateway = daddr;
2017         rth->rt_iif     =
2018                 rth->fl.iif     = in_dev->dev->ifindex;
2019         rth->u.dst.dev  = (out_dev)->dev;
2020         dev_hold(rth->u.dst.dev);
2021         rth->idev       = in_dev_get(rth->u.dst.dev);
2022         rth->fl.oif     = 0;
2023         rth->rt_spec_dst= spec_dst;
2024
2025         rth->u.dst.input = ip_forward;
2026         rth->u.dst.output = ip_output;
2027         rth->rt_genid = rt_genid(dev_net(rth->u.dst.dev));
2028
2029         rt_set_nexthop(rth, res, itag);
2030
2031         rth->rt_flags = flags;
2032
2033         *result = rth;
2034         err = 0;
2035  cleanup:
2036         /* release the working reference to the output device */
2037         in_dev_put(out_dev);
2038         return err;
2039 }
2040
2041 static int ip_mkroute_input(struct sk_buff *skb,
2042                             struct fib_result *res,
2043                             const struct flowi *fl,
2044                             struct in_device *in_dev,
2045                             __be32 daddr, __be32 saddr, u32 tos)
2046 {
2047         struct rtable* rth = NULL;
2048         int err;
2049         unsigned hash;
2050
2051 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2052         if (res->fi && res->fi->fib_nhs > 1 && fl->oif == 0)
2053                 fib_select_multipath(fl, res);
2054 #endif
2055
2056         /* create a routing cache entry */
2057         err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
2058         if (err)
2059                 return err;
2060
2061         /* put it into the cache */
2062         hash = rt_hash(daddr, saddr, fl->iif,
2063                        rt_genid(dev_net(rth->u.dst.dev)));
2064         return rt_intern_hash(hash, rth, NULL, skb);
2065 }
2066
2067 /*
2068  *      NOTE. We drop all the packets that has local source
2069  *      addresses, because every properly looped back packet
2070  *      must have correct destination already attached by output routine.
2071  *
2072  *      Such approach solves two big problems:
2073  *      1. Not simplex devices are handled properly.
2074  *      2. IP spoofing attempts are filtered with 100% of guarantee.
2075  */
2076
2077 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2078                                u8 tos, struct net_device *dev)
2079 {
2080         struct fib_result res;
2081         struct in_device *in_dev = in_dev_get(dev);
2082         struct flowi fl = { .nl_u = { .ip4_u =
2083                                       { .daddr = daddr,
2084                                         .saddr = saddr,
2085                                         .tos = tos,
2086                                         .scope = RT_SCOPE_UNIVERSE,
2087                                       } },
2088                             .mark = skb->mark,
2089                             .iif = dev->ifindex };
2090         unsigned        flags = 0;
2091         u32             itag = 0;
2092         struct rtable * rth;
2093         unsigned        hash;
2094         __be32          spec_dst;
2095         int             err = -EINVAL;
2096         int             free_res = 0;
2097         struct net    * net = dev_net(dev);
2098
2099         /* IP on this device is disabled. */
2100
2101         if (!in_dev)
2102                 goto out;
2103
2104         /* Check for the most weird martians, which can be not detected
2105            by fib_lookup.
2106          */
2107
2108         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
2109             ipv4_is_loopback(saddr))
2110                 goto martian_source;
2111
2112         if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
2113                 goto brd_input;
2114
2115         /* Accept zero addresses only to limited broadcast;
2116          * I even do not know to fix it or not. Waiting for complains :-)
2117          */
2118         if (ipv4_is_zeronet(saddr))
2119                 goto martian_source;
2120
2121         if (ipv4_is_lbcast(daddr) || ipv4_is_zeronet(daddr) ||
2122             ipv4_is_loopback(daddr))
2123                 goto martian_destination;
2124
2125         /*
2126          *      Now we are ready to route packet.
2127          */
2128         if ((err = fib_lookup(net, &fl, &res)) != 0) {
2129                 if (!IN_DEV_FORWARD(in_dev))
2130                         goto e_hostunreach;
2131                 goto no_route;
2132         }
2133         free_res = 1;
2134
2135         RT_CACHE_STAT_INC(in_slow_tot);
2136
2137         if (res.type == RTN_BROADCAST)
2138                 goto brd_input;
2139
2140         if (res.type == RTN_LOCAL) {
2141                 int result;
2142                 result = fib_validate_source(saddr, daddr, tos,
2143                                              net->loopback_dev->ifindex,
2144                                              dev, &spec_dst, &itag, skb->mark);
2145                 if (result < 0)
2146                         goto martian_source;
2147                 if (result)
2148                         flags |= RTCF_DIRECTSRC;
2149                 spec_dst = daddr;
2150                 goto local_input;
2151         }
2152
2153         if (!IN_DEV_FORWARD(in_dev))
2154                 goto e_hostunreach;
2155         if (res.type != RTN_UNICAST)
2156                 goto martian_destination;
2157
2158         err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
2159 done:
2160         in_dev_put(in_dev);
2161         if (free_res)
2162                 fib_res_put(&res);
2163 out:    return err;
2164
2165 brd_input:
2166         if (skb->protocol != htons(ETH_P_IP))
2167                 goto e_inval;
2168
2169         if (ipv4_is_zeronet(saddr))
2170                 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2171         else {
2172                 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
2173                                           &itag, skb->mark);
2174                 if (err < 0)
2175                         goto martian_source;
2176                 if (err)
2177                         flags |= RTCF_DIRECTSRC;
2178         }
2179         flags |= RTCF_BROADCAST;
2180         res.type = RTN_BROADCAST;
2181         RT_CACHE_STAT_INC(in_brd);
2182
2183 local_input:
2184         rth = dst_alloc(&ipv4_dst_ops);
2185         if (!rth)
2186                 goto e_nobufs;
2187
2188         rth->u.dst.output= ip_rt_bug;
2189         rth->rt_genid = rt_genid(net);
2190
2191         atomic_set(&rth->u.dst.__refcnt, 1);
2192         rth->u.dst.flags= DST_HOST;
2193         if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
2194                 rth->u.dst.flags |= DST_NOPOLICY;
2195         rth->fl.fl4_dst = daddr;
2196         rth->rt_dst     = daddr;
2197         rth->fl.fl4_tos = tos;
2198         rth->fl.mark    = skb->mark;
2199         rth->fl.fl4_src = saddr;
2200         rth->rt_src     = saddr;
2201 #ifdef CONFIG_NET_CLS_ROUTE
2202         rth->u.dst.tclassid = itag;
2203 #endif
2204         rth->rt_iif     =
2205         rth->fl.iif     = dev->ifindex;
2206         rth->u.dst.dev  = net->loopback_dev;
2207         dev_hold(rth->u.dst.dev);
2208         rth->idev       = in_dev_get(rth->u.dst.dev);
2209         rth->rt_gateway = daddr;
2210         rth->rt_spec_dst= spec_dst;
2211         rth->u.dst.input= ip_local_deliver;
2212         rth->rt_flags   = flags|RTCF_LOCAL;
2213         if (res.type == RTN_UNREACHABLE) {
2214                 rth->u.dst.input= ip_error;
2215                 rth->u.dst.error= -err;
2216                 rth->rt_flags   &= ~RTCF_LOCAL;
2217         }
2218         rth->rt_type    = res.type;
2219         hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net));
2220         err = rt_intern_hash(hash, rth, NULL, skb);
2221         goto done;
2222
2223 no_route:
2224         RT_CACHE_STAT_INC(in_no_route);
2225         spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2226         res.type = RTN_UNREACHABLE;
2227         if (err == -ESRCH)
2228                 err = -ENETUNREACH;
2229         goto local_input;
2230
2231         /*
2232          *      Do not cache martian addresses: they should be logged (RFC1812)
2233          */
2234 martian_destination:
2235         RT_CACHE_STAT_INC(in_martian_dst);
2236 #ifdef CONFIG_IP_ROUTE_VERBOSE
2237         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
2238                 printk(KERN_WARNING "martian destination %pI4 from %pI4, dev %s\n",
2239                         &daddr, &saddr, dev->name);
2240 #endif
2241
2242 e_hostunreach:
2243         err = -EHOSTUNREACH;
2244         goto done;
2245
2246 e_inval:
2247         err = -EINVAL;
2248         goto done;
2249
2250 e_nobufs:
2251         err = -ENOBUFS;
2252         goto done;
2253
2254 martian_source:
2255         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2256         goto e_inval;
2257 }
2258
2259 int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2260                    u8 tos, struct net_device *dev)
2261 {
2262         struct rtable * rth;
2263         unsigned        hash;
2264         int iif = dev->ifindex;
2265         struct net *net;
2266
2267         net = dev_net(dev);
2268
2269         if (!rt_caching(net))
2270                 goto skip_cache;
2271
2272         tos &= IPTOS_RT_MASK;
2273         hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2274
2275         rcu_read_lock();
2276         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2277              rth = rcu_dereference(rth->u.dst.rt_next)) {
2278                 if (((rth->fl.fl4_dst ^ daddr) |
2279                      (rth->fl.fl4_src ^ saddr) |
2280                      (rth->fl.iif ^ iif) |
2281                      rth->fl.oif |
2282                      (rth->fl.fl4_tos ^ tos)) == 0 &&
2283                     rth->fl.mark == skb->mark &&
2284                     net_eq(dev_net(rth->u.dst.dev), net) &&
2285                     !rt_is_expired(rth)) {
2286                         dst_use(&rth->u.dst, jiffies);
2287                         RT_CACHE_STAT_INC(in_hit);
2288                         rcu_read_unlock();
2289                         skb_dst_set(skb, &rth->u.dst);
2290                         return 0;
2291                 }
2292                 RT_CACHE_STAT_INC(in_hlist_search);
2293         }
2294         rcu_read_unlock();
2295
2296 skip_cache:
2297         /* Multicast recognition logic is moved from route cache to here.
2298            The problem was that too many Ethernet cards have broken/missing
2299            hardware multicast filters :-( As result the host on multicasting
2300            network acquires a lot of useless route cache entries, sort of
2301            SDR messages from all the world. Now we try to get rid of them.
2302            Really, provided software IP multicast filter is organized
2303            reasonably (at least, hashed), it does not result in a slowdown
2304            comparing with route cache reject entries.
2305            Note, that multicast routers are not affected, because
2306            route cache entry is created eventually.
2307          */
2308         if (ipv4_is_multicast(daddr)) {
2309                 struct in_device *in_dev;
2310
2311                 rcu_read_lock();
2312                 if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
2313                         int our = ip_check_mc(in_dev, daddr, saddr,
2314                                 ip_hdr(skb)->protocol);
2315                         if (our
2316 #ifdef CONFIG_IP_MROUTE
2317                             || (!ipv4_is_local_multicast(daddr) &&
2318                                 IN_DEV_MFORWARD(in_dev))
2319 #endif
2320                             ) {
2321                                 rcu_read_unlock();
2322                                 return ip_route_input_mc(skb, daddr, saddr,
2323                                                          tos, dev, our);
2324                         }
2325                 }
2326                 rcu_read_unlock();
2327                 return -EINVAL;
2328         }
2329         return ip_route_input_slow(skb, daddr, saddr, tos, dev);
2330 }
2331
2332 static int __mkroute_output(struct rtable **result,
2333                             struct fib_result *res,
2334                             const struct flowi *fl,
2335                             const struct flowi *oldflp,
2336                             struct net_device *dev_out,
2337                             unsigned flags)
2338 {
2339         struct rtable *rth;
2340         struct in_device *in_dev;
2341         u32 tos = RT_FL_TOS(oldflp);
2342         int err = 0;
2343
2344         if (ipv4_is_loopback(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
2345                 return -EINVAL;
2346
2347         if (fl->fl4_dst == htonl(0xFFFFFFFF))
2348                 res->type = RTN_BROADCAST;
2349         else if (ipv4_is_multicast(fl->fl4_dst))
2350                 res->type = RTN_MULTICAST;
2351         else if (ipv4_is_lbcast(fl->fl4_dst) || ipv4_is_zeronet(fl->fl4_dst))
2352                 return -EINVAL;
2353
2354         if (dev_out->flags & IFF_LOOPBACK)
2355                 flags |= RTCF_LOCAL;
2356
2357         /* get work reference to inet device */
2358         in_dev = in_dev_get(dev_out);
2359         if (!in_dev)
2360                 return -EINVAL;
2361
2362         if (res->type == RTN_BROADCAST) {
2363                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2364                 if (res->fi) {
2365                         fib_info_put(res->fi);
2366                         res->fi = NULL;
2367                 }
2368         } else if (res->type == RTN_MULTICAST) {
2369                 flags |= RTCF_MULTICAST|RTCF_LOCAL;
2370                 if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
2371                                  oldflp->proto))
2372                         flags &= ~RTCF_LOCAL;
2373                 /* If multicast route do not exist use
2374                    default one, but do not gateway in this case.
2375                    Yes, it is hack.
2376                  */
2377                 if (res->fi && res->prefixlen < 4) {
2378                         fib_info_put(res->fi);
2379                         res->fi = NULL;
2380                 }
2381         }
2382
2383
2384         rth = dst_alloc(&ipv4_dst_ops);
2385         if (!rth) {
2386                 err = -ENOBUFS;
2387                 goto cleanup;
2388         }
2389
2390         atomic_set(&rth->u.dst.__refcnt, 1);
2391         rth->u.dst.flags= DST_HOST;
2392         if (IN_DEV_CONF_GET(in_dev, NOXFRM))
2393                 rth->u.dst.flags |= DST_NOXFRM;
2394         if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
2395                 rth->u.dst.flags |= DST_NOPOLICY;
2396
2397         rth->fl.fl4_dst = oldflp->fl4_dst;
2398         rth->fl.fl4_tos = tos;
2399         rth->fl.fl4_src = oldflp->fl4_src;
2400         rth->fl.oif     = oldflp->oif;
2401         rth->fl.mark    = oldflp->mark;
2402         rth->rt_dst     = fl->fl4_dst;
2403         rth->rt_src     = fl->fl4_src;
2404         rth->rt_iif     = oldflp->oif ? : dev_out->ifindex;
2405         /* get references to the devices that are to be hold by the routing
2406            cache entry */
2407         rth->u.dst.dev  = dev_out;
2408         dev_hold(dev_out);
2409         rth->idev       = in_dev_get(dev_out);
2410         rth->rt_gateway = fl->fl4_dst;
2411         rth->rt_spec_dst= fl->fl4_src;
2412
2413         rth->u.dst.output=ip_output;
2414         rth->rt_genid = rt_genid(dev_net(dev_out));
2415
2416         RT_CACHE_STAT_INC(out_slow_tot);
2417
2418         if (flags & RTCF_LOCAL) {
2419                 rth->u.dst.input = ip_local_deliver;
2420                 rth->rt_spec_dst = fl->fl4_dst;
2421         }
2422         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2423                 rth->rt_spec_dst = fl->fl4_src;
2424                 if (flags & RTCF_LOCAL &&
2425                     !(dev_out->flags & IFF_LOOPBACK)) {
2426                         rth->u.dst.output = ip_mc_output;
2427                         RT_CACHE_STAT_INC(out_slow_mc);
2428                 }
2429 #ifdef CONFIG_IP_MROUTE
2430                 if (res->type == RTN_MULTICAST) {
2431                         if (IN_DEV_MFORWARD(in_dev) &&
2432                             !ipv4_is_local_multicast(oldflp->fl4_dst)) {
2433                                 rth->u.dst.input = ip_mr_input;
2434                                 rth->u.dst.output = ip_mc_output;
2435                         }
2436                 }
2437 #endif
2438         }
2439
2440         rt_set_nexthop(rth, res, 0);
2441
2442         rth->rt_flags = flags;
2443
2444         *result = rth;
2445  cleanup:
2446         /* release work reference to inet device */
2447         in_dev_put(in_dev);
2448
2449         return err;
2450 }
2451
2452 static int ip_mkroute_output(struct rtable **rp,
2453                              struct fib_result *res,
2454                              const struct flowi *fl,
2455                              const struct flowi *oldflp,
2456                              struct net_device *dev_out,
2457                              unsigned flags)
2458 {
2459         struct rtable *rth = NULL;
2460         int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
2461         unsigned hash;
2462         if (err == 0) {
2463                 hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif,
2464                                rt_genid(dev_net(dev_out)));
2465                 err = rt_intern_hash(hash, rth, rp, NULL);
2466         }
2467
2468         return err;
2469 }
2470
2471 /*
2472  * Major route resolver routine.
2473  */
2474
2475 static int ip_route_output_slow(struct net *net, struct rtable **rp,
2476                                 const struct flowi *oldflp)
2477 {
2478         u32 tos = RT_FL_TOS(oldflp);
2479         struct flowi fl = { .nl_u = { .ip4_u =
2480                                       { .daddr = oldflp->fl4_dst,
2481                                         .saddr = oldflp->fl4_src,
2482                                         .tos = tos & IPTOS_RT_MASK,
2483                                         .scope = ((tos & RTO_ONLINK) ?
2484                                                   RT_SCOPE_LINK :
2485                                                   RT_SCOPE_UNIVERSE),
2486                                       } },
2487                             .mark = oldflp->mark,
2488                             .iif = net->loopback_dev->ifindex,
2489                             .oif = oldflp->oif };
2490         struct fib_result res;
2491         unsigned flags = 0;
2492         struct net_device *dev_out = NULL;
2493         int free_res = 0;
2494         int err;
2495
2496
2497         res.fi          = NULL;
2498 #ifdef CONFIG_IP_MULTIPLE_TABLES
2499         res.r           = NULL;
2500 #endif
2501
2502         if (oldflp->fl4_src) {
2503                 err = -EINVAL;
2504                 if (ipv4_is_multicast(oldflp->fl4_src) ||
2505                     ipv4_is_lbcast(oldflp->fl4_src) ||
2506                     ipv4_is_zeronet(oldflp->fl4_src))
2507                         goto out;
2508
2509                 /* I removed check for oif == dev_out->oif here.
2510                    It was wrong for two reasons:
2511                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2512                       is assigned to multiple interfaces.
2513                    2. Moreover, we are allowed to send packets with saddr
2514                       of another iface. --ANK
2515                  */
2516
2517                 if (oldflp->oif == 0
2518                     && (ipv4_is_multicast(oldflp->fl4_dst) ||
2519                         oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
2520                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2521                         dev_out = ip_dev_find(net, oldflp->fl4_src);
2522                         if (dev_out == NULL)
2523                                 goto out;
2524
2525                         /* Special hack: user can direct multicasts
2526                            and limited broadcast via necessary interface
2527                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2528                            This hack is not just for fun, it allows
2529                            vic,vat and friends to work.
2530                            They bind socket to loopback, set ttl to zero
2531                            and expect that it will work.
2532                            From the viewpoint of routing cache they are broken,
2533                            because we are not allowed to build multicast path
2534                            with loopback source addr (look, routing cache
2535                            cannot know, that ttl is zero, so that packet
2536                            will not leave this host and route is valid).
2537                            Luckily, this hack is good workaround.
2538                          */
2539
2540                         fl.oif = dev_out->ifindex;
2541                         goto make_route;
2542                 }
2543
2544                 if (!(oldflp->flags & FLOWI_FLAG_ANYSRC)) {
2545                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2546                         dev_out = ip_dev_find(net, oldflp->fl4_src);
2547                         if (dev_out == NULL)
2548                                 goto out;
2549                         dev_put(dev_out);
2550                         dev_out = NULL;
2551                 }
2552         }
2553
2554
2555         if (oldflp->oif) {
2556                 dev_out = dev_get_by_index(net, oldflp->oif);
2557                 err = -ENODEV;
2558                 if (dev_out == NULL)
2559                         goto out;
2560
2561                 /* RACE: Check return value of inet_select_addr instead. */
2562                 if (__in_dev_get_rtnl(dev_out) == NULL) {
2563                         dev_put(dev_out);
2564                         goto out;       /* Wrong error code */
2565                 }
2566
2567                 if (ipv4_is_local_multicast(oldflp->fl4_dst) ||
2568                     oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
2569                         if (!fl.fl4_src)
2570                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2571                                                               RT_SCOPE_LINK);
2572                         goto make_route;
2573                 }
2574                 if (!fl.fl4_src) {
2575                         if (ipv4_is_multicast(oldflp->fl4_dst))
2576                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2577                                                               fl.fl4_scope);
2578                         else if (!oldflp->fl4_dst)
2579                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2580                                                               RT_SCOPE_HOST);
2581                 }
2582         }
2583
2584         if (!fl.fl4_dst) {
2585                 fl.fl4_dst = fl.fl4_src;
2586                 if (!fl.fl4_dst)
2587                         fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
2588                 if (dev_out)
2589                         dev_put(dev_out);
2590                 dev_out = net->loopback_dev;
2591                 dev_hold(dev_out);
2592                 fl.oif = net->loopback_dev->ifindex;
2593                 res.type = RTN_LOCAL;
2594                 flags |= RTCF_LOCAL;
2595                 goto make_route;
2596         }
2597
2598         if (fib_lookup(net, &fl, &res)) {
2599                 res.fi = NULL;
2600                 if (oldflp->oif) {
2601                         /* Apparently, routing tables are wrong. Assume,
2602                            that the destination is on link.
2603
2604                            WHY? DW.
2605                            Because we are allowed to send to iface
2606                            even if it has NO routes and NO assigned
2607                            addresses. When oif is specified, routing
2608                            tables are looked up with only one purpose:
2609                            to catch if destination is gatewayed, rather than
2610                            direct. Moreover, if MSG_DONTROUTE is set,
2611                            we send packet, ignoring both routing tables
2612                            and ifaddr state. --ANK
2613
2614
2615                            We could make it even if oif is unknown,
2616                            likely IPv6, but we do not.
2617                          */
2618
2619                         if (fl.fl4_src == 0)
2620                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2621                                                               RT_SCOPE_LINK);
2622                         res.type = RTN_UNICAST;
2623                         goto make_route;
2624                 }
2625                 if (dev_out)
2626                         dev_put(dev_out);
2627                 err = -ENETUNREACH;
2628                 goto out;
2629         }
2630         free_res = 1;
2631
2632         if (res.type == RTN_LOCAL) {
2633                 if (!fl.fl4_src)
2634                         fl.fl4_src = fl.fl4_dst;
2635                 if (dev_out)
2636                         dev_put(dev_out);
2637                 dev_out = net->loopback_dev;
2638                 dev_hold(dev_out);
2639                 fl.oif = dev_out->ifindex;
2640                 if (res.fi)
2641                         fib_info_put(res.fi);
2642                 res.fi = NULL;
2643                 flags |= RTCF_LOCAL;
2644                 goto make_route;
2645         }
2646
2647 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2648         if (res.fi->fib_nhs > 1 && fl.oif == 0)
2649                 fib_select_multipath(&fl, &res);
2650         else
2651 #endif
2652         if (!res.prefixlen && res.type == RTN_UNICAST && !fl.oif)
2653                 fib_select_default(net, &fl, &res);
2654
2655         if (!fl.fl4_src)
2656                 fl.fl4_src = FIB_RES_PREFSRC(res);
2657
2658         if (dev_out)
2659                 dev_put(dev_out);
2660         dev_out = FIB_RES_DEV(res);
2661         dev_hold(dev_out);
2662         fl.oif = dev_out->ifindex;
2663
2664
2665 make_route:
2666         err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
2667
2668
2669         if (free_res)
2670                 fib_res_put(&res);
2671         if (dev_out)
2672                 dev_put(dev_out);
2673 out:    return err;
2674 }
2675
2676 int __ip_route_output_key(struct net *net, struct rtable **rp,
2677                           const struct flowi *flp)
2678 {
2679         unsigned hash;
2680         struct rtable *rth;
2681
2682         if (!rt_caching(net))
2683                 goto slow_output;
2684
2685         hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif, rt_genid(net));
2686
2687         rcu_read_lock_bh();
2688         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2689                 rth = rcu_dereference(rth->u.dst.rt_next)) {
2690                 if (rth->fl.fl4_dst == flp->fl4_dst &&
2691                     rth->fl.fl4_src == flp->fl4_src &&
2692                     rth->fl.iif == 0 &&
2693                     rth->fl.oif == flp->oif &&
2694                     rth->fl.mark == flp->mark &&
2695                     !((rth->fl.fl4_tos ^ flp->fl4_tos) &
2696                             (IPTOS_RT_MASK | RTO_ONLINK)) &&
2697                     net_eq(dev_net(rth->u.dst.dev), net) &&
2698                     !rt_is_expired(rth)) {
2699                         dst_use(&rth->u.dst, jiffies);
2700                         RT_CACHE_STAT_INC(out_hit);
2701                         rcu_read_unlock_bh();
2702                         *rp = rth;
2703                         return 0;
2704                 }
2705                 RT_CACHE_STAT_INC(out_hlist_search);
2706         }
2707         rcu_read_unlock_bh();
2708
2709 slow_output:
2710         return ip_route_output_slow(net, rp, flp);
2711 }
2712
2713 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2714
2715 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2716 {
2717 }
2718
2719 static struct dst_ops ipv4_dst_blackhole_ops = {
2720         .family                 =       AF_INET,
2721         .protocol               =       cpu_to_be16(ETH_P_IP),
2722         .destroy                =       ipv4_dst_destroy,
2723         .check                  =       ipv4_dst_check,
2724         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2725         .entries                =       ATOMIC_INIT(0),
2726 };
2727
2728
2729 static int ipv4_dst_blackhole(struct net *net, struct rtable **rp, struct flowi *flp)
2730 {
2731         struct rtable *ort = *rp;
2732         struct rtable *rt = (struct rtable *)
2733                 dst_alloc(&ipv4_dst_blackhole_ops);
2734
2735         if (rt) {
2736                 struct dst_entry *new = &rt->u.dst;
2737
2738                 atomic_set(&new->__refcnt, 1);
2739                 new->__use = 1;
2740                 new->input = dst_discard;
2741                 new->output = dst_discard;
2742                 memcpy(new->metrics, ort->u.dst.metrics, RTAX_MAX*sizeof(u32));
2743
2744                 new->dev = ort->u.dst.dev;
2745                 if (new->dev)
2746                         dev_hold(new->dev);
2747
2748                 rt->fl = ort->fl;
2749
2750                 rt->idev = ort->idev;
2751                 if (rt->idev)
2752                         in_dev_hold(rt->idev);
2753                 rt->rt_genid = rt_genid(net);
2754                 rt->rt_flags = ort->rt_flags;
2755                 rt->rt_type = ort->rt_type;
2756                 rt->rt_dst = ort->rt_dst;
2757                 rt->rt_src = ort->rt_src;
2758                 rt->rt_iif = ort->rt_iif;
2759                 rt->rt_gateway = ort->rt_gateway;
2760                 rt->rt_spec_dst = ort->rt_spec_dst;
2761                 rt->peer = ort->peer;
2762                 if (rt->peer)
2763                         atomic_inc(&rt->peer->refcnt);
2764
2765                 dst_free(new);
2766         }
2767
2768         dst_release(&(*rp)->u.dst);
2769         *rp = rt;
2770         return (rt ? 0 : -ENOMEM);
2771 }
2772
2773 int ip_route_output_flow(struct net *net, struct rtable **rp, struct flowi *flp,
2774                          struct sock *sk, int flags)
2775 {
2776         int err;
2777
2778         if ((err = __ip_route_output_key(net, rp, flp)) != 0)
2779                 return err;
2780
2781         if (flp->proto) {
2782                 if (!flp->fl4_src)
2783                         flp->fl4_src = (*rp)->rt_src;
2784                 if (!flp->fl4_dst)
2785                         flp->fl4_dst = (*rp)->rt_dst;
2786                 err = __xfrm_lookup(net, (struct dst_entry **)rp, flp, sk,
2787                                     flags ? XFRM_LOOKUP_WAIT : 0);
2788                 if (err == -EREMOTE)
2789                         err = ipv4_dst_blackhole(net, rp, flp);
2790
2791                 return err;
2792         }
2793
2794         return 0;
2795 }
2796
2797 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2798
2799 int ip_route_output_key(struct net *net, struct rtable **rp, struct flowi *flp)
2800 {
2801         return ip_route_output_flow(net, rp, flp, NULL, 0);
2802 }
2803
2804 static int rt_fill_info(struct net *net,
2805                         struct sk_buff *skb, u32 pid, u32 seq, int event,
2806                         int nowait, unsigned int flags)
2807 {
2808         struct rtable *rt = skb_rtable(skb);
2809         struct rtmsg *r;
2810         struct nlmsghdr *nlh;
2811         long expires;
2812         u32 id = 0, ts = 0, tsage = 0, error;
2813
2814         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2815         if (nlh == NULL)
2816                 return -EMSGSIZE;
2817
2818         r = nlmsg_data(nlh);
2819         r->rtm_family    = AF_INET;
2820         r->rtm_dst_len  = 32;
2821         r->rtm_src_len  = 0;
2822         r->rtm_tos      = rt->fl.fl4_tos;
2823         r->rtm_table    = RT_TABLE_MAIN;
2824         NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
2825         r->rtm_type     = rt->rt_type;
2826         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2827         r->rtm_protocol = RTPROT_UNSPEC;
2828         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2829         if (rt->rt_flags & RTCF_NOTIFY)
2830                 r->rtm_flags |= RTM_F_NOTIFY;
2831
2832         NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2833
2834         if (rt->fl.fl4_src) {
2835                 r->rtm_src_len = 32;
2836                 NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src);
2837         }
2838         if (rt->u.dst.dev)
2839                 NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex);
2840 #ifdef CONFIG_NET_CLS_ROUTE
2841         if (rt->u.dst.tclassid)
2842                 NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid);
2843 #endif
2844         if (rt->fl.iif)
2845                 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
2846         else if (rt->rt_src != rt->fl.fl4_src)
2847                 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2848
2849         if (rt->rt_dst != rt->rt_gateway)
2850                 NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2851
2852         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2853                 goto nla_put_failure;
2854
2855         error = rt->u.dst.error;
2856         expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
2857         if (rt->peer) {
2858                 id = rt->peer->ip_id_count;
2859                 if (rt->peer->tcp_ts_stamp) {
2860                         ts = rt->peer->tcp_ts;
2861                         tsage = get_seconds() - rt->peer->tcp_ts_stamp;
2862                 }
2863         }
2864
2865         if (rt->fl.iif) {
2866 #ifdef CONFIG_IP_MROUTE
2867                 __be32 dst = rt->rt_dst;
2868
2869                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2870                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2871                         int err = ipmr_get_route(net, skb, r, nowait);
2872                         if (err <= 0) {
2873                                 if (!nowait) {
2874                                         if (err == 0)
2875                                                 return 0;
2876                                         goto nla_put_failure;
2877                                 } else {
2878                                         if (err == -EMSGSIZE)
2879                                                 goto nla_put_failure;
2880                                         error = err;
2881                                 }
2882                         }
2883                 } else
2884 #endif
2885                         NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif);
2886         }
2887
2888         if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage,
2889                                expires, error) < 0)
2890                 goto nla_put_failure;
2891
2892         return nlmsg_end(skb, nlh);
2893
2894 nla_put_failure:
2895         nlmsg_cancel(skb, nlh);
2896         return -EMSGSIZE;
2897 }
2898
2899 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
2900 {
2901         struct net *net = sock_net(in_skb->sk);
2902         struct rtmsg *rtm;
2903         struct nlattr *tb[RTA_MAX+1];
2904         struct rtable *rt = NULL;
2905         __be32 dst = 0;
2906         __be32 src = 0;
2907         u32 iif;
2908         int err;
2909         struct sk_buff *skb;
2910
2911         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2912         if (err < 0)
2913                 goto errout;
2914
2915         rtm = nlmsg_data(nlh);
2916
2917         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2918         if (skb == NULL) {
2919                 err = -ENOBUFS;
2920                 goto errout;
2921         }
2922
2923         /* Reserve room for dummy headers, this skb can pass
2924            through good chunk of routing engine.
2925          */
2926         skb_reset_mac_header(skb);
2927         skb_reset_network_header(skb);
2928
2929         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2930         ip_hdr(skb)->protocol = IPPROTO_ICMP;
2931         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2932
2933         src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2934         dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2935         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2936
2937         if (iif) {
2938                 struct net_device *dev;
2939
2940                 dev = __dev_get_by_index(net, iif);
2941                 if (dev == NULL) {
2942                         err = -ENODEV;
2943                         goto errout_free;
2944                 }
2945
2946                 skb->protocol   = htons(ETH_P_IP);
2947                 skb->dev        = dev;
2948                 local_bh_disable();
2949                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2950                 local_bh_enable();
2951
2952                 rt = skb_rtable(skb);
2953                 if (err == 0 && rt->u.dst.error)
2954                         err = -rt->u.dst.error;
2955         } else {
2956                 struct flowi fl = {
2957                         .nl_u = {
2958                                 .ip4_u = {
2959                                         .daddr = dst,
2960                                         .saddr = src,
2961                                         .tos = rtm->rtm_tos,
2962                                 },
2963                         },
2964                         .oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
2965                 };
2966                 err = ip_route_output_key(net, &rt, &fl);
2967         }
2968
2969         if (err)
2970                 goto errout_free;
2971
2972         skb_dst_set(skb, &rt->u.dst);
2973         if (rtm->rtm_flags & RTM_F_NOTIFY)
2974                 rt->rt_flags |= RTCF_NOTIFY;
2975
2976         err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2977                            RTM_NEWROUTE, 0, 0);
2978         if (err <= 0)
2979                 goto errout_free;
2980
2981         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2982 errout:
2983         return err;
2984
2985 errout_free:
2986         kfree_skb(skb);
2987         goto errout;
2988 }
2989
2990 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
2991 {
2992         struct rtable *rt;
2993         int h, s_h;
2994         int idx, s_idx;
2995         struct net *net;
2996
2997         net = sock_net(skb->sk);
2998
2999         s_h = cb->args[0];
3000         if (s_h < 0)
3001                 s_h = 0;
3002         s_idx = idx = cb->args[1];
3003         for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
3004                 if (!rt_hash_table[h].chain)
3005                         continue;
3006                 rcu_read_lock_bh();
3007                 for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
3008                      rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
3009                         if (!net_eq(dev_net(rt->u.dst.dev), net) || idx < s_idx)
3010                                 continue;
3011                         if (rt_is_expired(rt))
3012                                 continue;
3013                         skb_dst_set(skb, dst_clone(&rt->u.dst));
3014                         if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
3015                                          cb->nlh->nlmsg_seq, RTM_NEWROUTE,
3016                                          1, NLM_F_MULTI) <= 0) {
3017                                 skb_dst_drop(skb);
3018                                 rcu_read_unlock_bh();
3019                                 goto done;
3020                         }
3021                         skb_dst_drop(skb);
3022                 }
3023                 rcu_read_unlock_bh();
3024         }
3025
3026 done:
3027         cb->args[0] = h;
3028         cb->args[1] = idx;
3029         return skb->len;
3030 }
3031
3032 void ip_rt_multicast_event(struct in_device *in_dev)
3033 {
3034         rt_cache_flush(dev_net(in_dev->dev), 0);
3035 }
3036
3037 #ifdef CONFIG_SYSCTL
3038 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
3039                                         void __user *buffer,
3040                                         size_t *lenp, loff_t *ppos)
3041 {
3042         if (write) {
3043                 int flush_delay;
3044                 ctl_table ctl;
3045                 struct net *net;
3046
3047                 memcpy(&ctl, __ctl, sizeof(ctl));
3048                 ctl.data = &flush_delay;
3049                 proc_dointvec(&ctl, write, buffer, lenp, ppos);
3050
3051                 net = (struct net *)__ctl->extra1;
3052                 rt_cache_flush(net, flush_delay);
3053                 return 0;
3054         }
3055
3056         return -EINVAL;
3057 }
3058
3059 static void rt_secret_reschedule(int old)
3060 {
3061         struct net *net;
3062         int new = ip_rt_secret_interval;
3063         int diff = new - old;
3064
3065         if (!diff)
3066                 return;
3067
3068         rtnl_lock();
3069         for_each_net(net) {
3070                 int deleted = del_timer_sync(&net->ipv4.rt_secret_timer);
3071
3072                 if (!new)
3073                         continue;
3074
3075                 if (deleted) {
3076                         long time = net->ipv4.rt_secret_timer.expires - jiffies;
3077
3078                         if (time <= 0 || (time += diff) <= 0)
3079                                 time = 0;
3080
3081                         net->ipv4.rt_secret_timer.expires = time;
3082                 } else
3083                         net->ipv4.rt_secret_timer.expires = new;
3084
3085                 net->ipv4.rt_secret_timer.expires += jiffies;
3086                 add_timer(&net->ipv4.rt_secret_timer);
3087         }
3088         rtnl_unlock();
3089 }
3090
3091 static int ipv4_sysctl_rt_secret_interval(ctl_table *ctl, int write,
3092                                           void __user *buffer, size_t *lenp,
3093                                           loff_t *ppos)
3094 {
3095         int old = ip_rt_secret_interval;
3096         int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
3097
3098         rt_secret_reschedule(old);
3099
3100         return ret;
3101 }
3102
3103 static ctl_table ipv4_route_table[] = {
3104         {
3105                 .procname       = "gc_thresh",
3106                 .data           = &ipv4_dst_ops.gc_thresh,
3107                 .maxlen         = sizeof(int),
3108                 .mode           = 0644,
3109                 .proc_handler   = proc_dointvec,
3110         },
3111         {
3112                 .procname       = "max_size",
3113                 .data           = &ip_rt_max_size,
3114                 .maxlen         = sizeof(int),
3115                 .mode           = 0644,
3116                 .proc_handler   = proc_dointvec,
3117         },
3118         {
3119                 /*  Deprecated. Use gc_min_interval_ms */
3120
3121                 .procname       = "gc_min_interval",
3122                 .data           = &ip_rt_gc_min_interval,
3123                 .maxlen         = sizeof(int),
3124                 .mode           = 0644,
3125                 .proc_handler   = proc_dointvec_jiffies,
3126         },
3127         {
3128                 .procname       = "gc_min_interval_ms",
3129                 .data           = &ip_rt_gc_min_interval,
3130                 .maxlen         = sizeof(int),
3131                 .mode           = 0644,
3132                 .proc_handler   = proc_dointvec_ms_jiffies,
3133         },
3134         {
3135                 .procname       = "gc_timeout",
3136                 .data           = &ip_rt_gc_timeout,
3137                 .maxlen         = sizeof(int),
3138                 .mode           = 0644,
3139                 .proc_handler   = proc_dointvec_jiffies,
3140         },
3141         {
3142                 .procname       = "gc_interval",
3143                 .data           = &ip_rt_gc_interval,
3144                 .maxlen         = sizeof(int),
3145                 .mode           = 0644,
3146                 .proc_handler   = proc_dointvec_jiffies,
3147         },
3148         {
3149                 .procname       = "redirect_load",
3150                 .data           = &ip_rt_redirect_load,
3151                 .maxlen         = sizeof(int),
3152                 .mode           = 0644,
3153                 .proc_handler   = proc_dointvec,
3154         },
3155         {
3156                 .procname       = "redirect_number",
3157                 .data           = &ip_rt_redirect_number,
3158                 .maxlen         = sizeof(int),
3159                 .mode           = 0644,
3160                 .proc_handler   = proc_dointvec,
3161         },
3162         {
3163                 .procname       = "redirect_silence",
3164                 .data           = &ip_rt_redirect_silence,
3165                 .maxlen         = sizeof(int),
3166                 .mode           = 0644,
3167                 .proc_handler   = proc_dointvec,
3168         },
3169         {
3170                 .procname       = "error_cost",
3171                 .data           = &ip_rt_error_cost,
3172                 .maxlen         = sizeof(int),
3173                 .mode           = 0644,
3174                 .proc_handler   = proc_dointvec,
3175         },
3176         {
3177                 .procname       = "error_burst",
3178                 .data           = &ip_rt_error_burst,
3179                 .maxlen         = sizeof(int),
3180                 .mode           = 0644,
3181                 .proc_handler   = proc_dointvec,
3182         },
3183         {
3184                 .procname       = "gc_elasticity",
3185                 .data           = &ip_rt_gc_elasticity,
3186                 .maxlen         = sizeof(int),
3187                 .mode           = 0644,
3188                 .proc_handler   = proc_dointvec,
3189         },
3190         {
3191                 .procname       = "mtu_expires",
3192                 .data           = &ip_rt_mtu_expires,
3193                 .maxlen         = sizeof(int),
3194                 .mode           = 0644,
3195                 .proc_handler   = proc_dointvec_jiffies,
3196         },
3197         {
3198                 .procname       = "min_pmtu",
3199                 .data           = &ip_rt_min_pmtu,
3200                 .maxlen         = sizeof(int),
3201                 .mode           = 0644,
3202                 .proc_handler   = proc_dointvec,
3203         },
3204         {
3205                 .procname       = "min_adv_mss",
3206                 .data           = &ip_rt_min_advmss,
3207                 .maxlen         = sizeof(int),
3208                 .mode           = 0644,
3209                 .proc_handler   = proc_dointvec,
3210         },
3211         {
3212                 .procname       = "secret_interval",
3213                 .data           = &ip_rt_secret_interval,
3214                 .maxlen         = sizeof(int),
3215                 .mode           = 0644,
3216                 .proc_handler   = ipv4_sysctl_rt_secret_interval,
3217         },
3218         { }
3219 };
3220
3221 static struct ctl_table empty[1];
3222
3223 static struct ctl_table ipv4_skeleton[] =
3224 {
3225         { .procname = "route", 
3226           .mode = 0555, .child = ipv4_route_table},
3227         { .procname = "neigh", 
3228           .mode = 0555, .child = empty},
3229         { }
3230 };
3231
3232 static __net_initdata struct ctl_path ipv4_path[] = {
3233         { .procname = "net", },
3234         { .procname = "ipv4", },
3235         { },
3236 };
3237
3238 static struct ctl_table ipv4_route_flush_table[] = {
3239         {
3240                 .procname       = "flush",
3241                 .maxlen         = sizeof(int),
3242                 .mode           = 0200,
3243                 .proc_handler   = ipv4_sysctl_rtcache_flush,
3244         },
3245         { },
3246 };
3247
3248 static __net_initdata struct ctl_path ipv4_route_path[] = {
3249         { .procname = "net", },
3250         { .procname = "ipv4", },
3251         { .procname = "route", },
3252         { },
3253 };
3254
3255 static __net_init int sysctl_route_net_init(struct net *net)
3256 {
3257         struct ctl_table *tbl;
3258
3259         tbl = ipv4_route_flush_table;
3260         if (net != &init_net) {
3261                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3262                 if (tbl == NULL)
3263                         goto err_dup;
3264         }
3265         tbl[0].extra1 = net;
3266
3267         net->ipv4.route_hdr =
3268                 register_net_sysctl_table(net, ipv4_route_path, tbl);
3269         if (net->ipv4.route_hdr == NULL)
3270                 goto err_reg;
3271         return 0;
3272
3273 err_reg:
3274         if (tbl != ipv4_route_flush_table)
3275                 kfree(tbl);
3276 err_dup:
3277         return -ENOMEM;
3278 }
3279
3280 static __net_exit void sysctl_route_net_exit(struct net *net)
3281 {
3282         struct ctl_table *tbl;
3283
3284         tbl = net->ipv4.route_hdr->ctl_table_arg;
3285         unregister_net_sysctl_table(net->ipv4.route_hdr);
3286         BUG_ON(tbl == ipv4_route_flush_table);
3287         kfree(tbl);
3288 }
3289
3290 static __net_initdata struct pernet_operations sysctl_route_ops = {
3291         .init = sysctl_route_net_init,
3292         .exit = sysctl_route_net_exit,
3293 };
3294 #endif
3295
3296
3297 static __net_init int rt_secret_timer_init(struct net *net)
3298 {
3299         atomic_set(&net->ipv4.rt_genid,
3300                         (int) ((num_physpages ^ (num_physpages>>8)) ^
3301                         (jiffies ^ (jiffies >> 7))));
3302
3303         net->ipv4.rt_secret_timer.function = rt_secret_rebuild;
3304         net->ipv4.rt_secret_timer.data = (unsigned long)net;
3305         init_timer_deferrable(&net->ipv4.rt_secret_timer);
3306
3307         if (ip_rt_secret_interval) {
3308                 net->ipv4.rt_secret_timer.expires =
3309                         jiffies + net_random() % ip_rt_secret_interval +
3310                         ip_rt_secret_interval;
3311                 add_timer(&net->ipv4.rt_secret_timer);
3312         }
3313         return 0;
3314 }
3315
3316 static __net_exit void rt_secret_timer_exit(struct net *net)
3317 {
3318         del_timer_sync(&net->ipv4.rt_secret_timer);
3319 }
3320
3321 static __net_initdata struct pernet_operations rt_secret_timer_ops = {
3322         .init = rt_secret_timer_init,
3323         .exit = rt_secret_timer_exit,
3324 };
3325
3326
3327 #ifdef CONFIG_NET_CLS_ROUTE
3328 struct ip_rt_acct *ip_rt_acct __read_mostly;
3329 #endif /* CONFIG_NET_CLS_ROUTE */
3330
3331 static __initdata unsigned long rhash_entries;
3332 static int __init set_rhash_entries(char *str)
3333 {
3334         if (!str)
3335                 return 0;
3336         rhash_entries = simple_strtoul(str, &str, 0);
3337         return 1;
3338 }
3339 __setup("rhash_entries=", set_rhash_entries);
3340
3341 int __init ip_rt_init(void)
3342 {
3343         int rc = 0;
3344
3345 #ifdef CONFIG_NET_CLS_ROUTE
3346         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3347         if (!ip_rt_acct)
3348                 panic("IP: failed to allocate ip_rt_acct\n");
3349 #endif
3350
3351         ipv4_dst_ops.kmem_cachep =
3352                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3353                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3354
3355         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3356
3357         rt_hash_table = (struct rt_hash_bucket *)
3358                 alloc_large_system_hash("IP route cache",
3359                                         sizeof(struct rt_hash_bucket),
3360                                         rhash_entries,
3361                                         (totalram_pages >= 128 * 1024) ?
3362                                         15 : 17,
3363                                         0,
3364                                         &rt_hash_log,
3365                                         &rt_hash_mask,
3366                                         rhash_entries ? 0 : 512 * 1024);
3367         memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3368         rt_hash_lock_init();
3369
3370         ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3371         ip_rt_max_size = (rt_hash_mask + 1) * 16;
3372
3373         devinet_init();
3374         ip_fib_init();
3375
3376         /* All the timers, started at system startup tend
3377            to synchronize. Perturb it a bit.
3378          */
3379         INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3380         expires_ljiffies = jiffies;
3381         schedule_delayed_work(&expires_work,
3382                 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3383
3384         if (register_pernet_subsys(&rt_secret_timer_ops))
3385                 printk(KERN_ERR "Unable to setup rt_secret_timer\n");
3386
3387         if (ip_rt_proc_init())
3388                 printk(KERN_ERR "Unable to create route proc files\n");
3389 #ifdef CONFIG_XFRM
3390         xfrm_init();
3391         xfrm4_init(ip_rt_max_size);
3392 #endif
3393         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);
3394
3395 #ifdef CONFIG_SYSCTL
3396         register_pernet_subsys(&sysctl_route_ops);
3397 #endif
3398         return rc;
3399 }
3400
3401 #ifdef CONFIG_SYSCTL
3402 /*
3403  * We really need to sanitize the damn ipv4 init order, then all
3404  * this nonsense will go away.
3405  */
3406 void __init ip_static_sysctl_init(void)
3407 {
3408         register_sysctl_paths(ipv4_path, ipv4_skeleton);
3409 }
3410 #endif
3411
3412 EXPORT_SYMBOL(__ip_select_ident);
3413 EXPORT_SYMBOL(ip_route_input);
3414 EXPORT_SYMBOL(ip_route_output_key);