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parisc-kernel-perf: BKL pushdown
[linux-2.6/libata-dev.git] / net / ipv4 / route.c
blob92f90ae46f4a3cc453ebf17c3a97d1df508394a6
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 * Version: $Id: route.c,v 1.103 2002/01/12 07:44:09 davem Exp $
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Alan Cox, <gw4pts@gw4pts.ampr.org>
13 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
14 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
15 *
16 * Fixes:
17 * Alan Cox : Verify area fixes.
18 * Alan Cox : cli() protects routing changes
19 * Rui Oliveira : ICMP routing table updates
20 * (rco@di.uminho.pt) Routing table insertion and update
21 * Linus Torvalds : Rewrote bits to be sensible
22 * Alan Cox : Added BSD route gw semantics
23 * Alan Cox : Super /proc >4K
24 * Alan Cox : MTU in route table
25 * Alan Cox : MSS actually. Also added the window
26 * clamper.
27 * Sam Lantinga : Fixed route matching in rt_del()
28 * Alan Cox : Routing cache support.
29 * Alan Cox : Removed compatibility cruft.
30 * Alan Cox : RTF_REJECT support.
31 * Alan Cox : TCP irtt support.
32 * Jonathan Naylor : Added Metric support.
33 * Miquel van Smoorenburg : BSD API fixes.
34 * Miquel van Smoorenburg : Metrics.
35 * Alan Cox : Use __u32 properly
36 * Alan Cox : Aligned routing errors more closely with BSD
37 * our system is still very different.
38 * Alan Cox : Faster /proc handling
39 * Alexey Kuznetsov : Massive rework to support tree based routing,
40 * routing caches and better behaviour.
41 *
42 * Olaf Erb : irtt wasn't being copied right.
43 * Bjorn Ekwall : Kerneld route support.
44 * Alan Cox : Multicast fixed (I hope)
45 * Pavel Krauz : Limited broadcast fixed
46 * Mike McLagan : Routing by source
47 * Alexey Kuznetsov : End of old history. Split to fib.c and
48 * route.c and rewritten from scratch.
49 * Andi Kleen : Load-limit warning messages.
50 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
51 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
52 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
53 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
54 * Marc Boucher : routing by fwmark
55 * Robert Olsson : Added rt_cache statistics
56 * Arnaldo C. Melo : Convert proc stuff to seq_file
57 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
58 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
59 * Ilia Sotnikov : Removed TOS from hash calculations
60 *
61 * This program is free software; you can redistribute it and/or
62 * modify it under the terms of the GNU General Public License
63 * as published by the Free Software Foundation; either version
64 * 2 of the License, or (at your option) any later version.
65 */
66
67 #include <linux/module.h>
68 #include <asm/uaccess.h>
69 #include <asm/system.h>
70 #include <linux/bitops.h>
71 #include <linux/types.h>
72 #include <linux/kernel.h>
73 #include <linux/mm.h>
74 #include <linux/bootmem.h>
75 #include <linux/string.h>
76 #include <linux/socket.h>
77 #include <linux/sockios.h>
78 #include <linux/errno.h>
79 #include <linux/in.h>
80 #include <linux/inet.h>
81 #include <linux/netdevice.h>
82 #include <linux/proc_fs.h>
83 #include <linux/init.h>
84 #include <linux/workqueue.h>
85 #include <linux/skbuff.h>
86 #include <linux/inetdevice.h>
87 #include <linux/igmp.h>
88 #include <linux/pkt_sched.h>
89 #include <linux/mroute.h>
90 #include <linux/netfilter_ipv4.h>
91 #include <linux/random.h>
92 #include <linux/jhash.h>
93 #include <linux/rcupdate.h>
94 #include <linux/times.h>
95 #include <net/dst.h>
96 #include <net/net_namespace.h>
97 #include <net/protocol.h>
98 #include <net/ip.h>
99 #include <net/route.h>
100 #include <net/inetpeer.h>
101 #include <net/sock.h>
102 #include <net/ip_fib.h>
103 #include <net/arp.h>
104 #include <net/tcp.h>
105 #include <net/icmp.h>
106 #include <net/xfrm.h>
107 #include <net/netevent.h>
108 #include <net/rtnetlink.h>
109 #ifdef CONFIG_SYSCTL
110 #include <linux/sysctl.h>
111 #endif
112
113 #define RT_FL_TOS(oldflp) \
114 ((u32)(oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
115
116 #define IP_MAX_MTU 0xFFF0
117
118 #define RT_GC_TIMEOUT (300*HZ)
119
120 static int ip_rt_max_size;
121 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
122 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
123 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
124 static int ip_rt_redirect_number __read_mostly = 9;
125 static int ip_rt_redirect_load __read_mostly = HZ / 50;
126 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
127 static int ip_rt_error_cost __read_mostly = HZ;
128 static int ip_rt_error_burst __read_mostly = 5 * HZ;
129 static int ip_rt_gc_elasticity __read_mostly = 8;
130 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
131 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
132 static int ip_rt_min_advmss __read_mostly = 256;
133 static int ip_rt_secret_interval __read_mostly = 10 * 60 * HZ;
134
135 static void rt_worker_func(struct work_struct *work);
136 static DECLARE_DELAYED_WORK(expires_work, rt_worker_func);
137 static struct timer_list rt_secret_timer;
138
139 /*
140 * Interface to generic destination cache.
141 */
142
143 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
144 static void ipv4_dst_destroy(struct dst_entry *dst);
145 static void ipv4_dst_ifdown(struct dst_entry *dst,
146 struct net_device *dev, int how);
147 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
148 static void ipv4_link_failure(struct sk_buff *skb);
149 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
150 static int rt_garbage_collect(struct dst_ops *ops);
151
152
153 static struct dst_ops ipv4_dst_ops = {
154 .family = AF_INET,
155 .protocol = __constant_htons(ETH_P_IP),
156 .gc = rt_garbage_collect,
157 .check = ipv4_dst_check,
158 .destroy = ipv4_dst_destroy,
159 .ifdown = ipv4_dst_ifdown,
160 .negative_advice = ipv4_negative_advice,
161 .link_failure = ipv4_link_failure,
162 .update_pmtu = ip_rt_update_pmtu,
163 .local_out = ip_local_out,
164 .entry_size = sizeof(struct rtable),
165 .entries = ATOMIC_INIT(0),
166 };
167
168 #define ECN_OR_COST(class) TC_PRIO_##class
169
170 const __u8 ip_tos2prio[16] = {
171 TC_PRIO_BESTEFFORT,
172 ECN_OR_COST(FILLER),
173 TC_PRIO_BESTEFFORT,
174 ECN_OR_COST(BESTEFFORT),
175 TC_PRIO_BULK,
176 ECN_OR_COST(BULK),
177 TC_PRIO_BULK,
178 ECN_OR_COST(BULK),
179 TC_PRIO_INTERACTIVE,
180 ECN_OR_COST(INTERACTIVE),
181 TC_PRIO_INTERACTIVE,
182 ECN_OR_COST(INTERACTIVE),
183 TC_PRIO_INTERACTIVE_BULK,
184 ECN_OR_COST(INTERACTIVE_BULK),
185 TC_PRIO_INTERACTIVE_BULK,
186 ECN_OR_COST(INTERACTIVE_BULK)
187 };
188
189
190 /*
191 * Route cache.
192 */
193
194 /* The locking scheme is rather straight forward:
195 *
196 * 1) Read-Copy Update protects the buckets of the central route hash.
197 * 2) Only writers remove entries, and they hold the lock
198 * as they look at rtable reference counts.
199 * 3) Only readers acquire references to rtable entries,
200 * they do so with atomic increments and with the
201 * lock held.
202 */
203
204 struct rt_hash_bucket {
205 struct rtable *chain;
206 };
207 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
208 defined(CONFIG_PROVE_LOCKING)
209 /*
210 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
211 * The size of this table is a power of two and depends on the number of CPUS.
212 * (on lockdep we have a quite big spinlock_t, so keep the size down there)
213 */
214 #ifdef CONFIG_LOCKDEP
215 # define RT_HASH_LOCK_SZ 256
216 #else
217 # if NR_CPUS >= 32
218 # define RT_HASH_LOCK_SZ 4096
219 # elif NR_CPUS >= 16
220 # define RT_HASH_LOCK_SZ 2048
221 # elif NR_CPUS >= 8
222 # define RT_HASH_LOCK_SZ 1024
223 # elif NR_CPUS >= 4
224 # define RT_HASH_LOCK_SZ 512
225 # else
226 # define RT_HASH_LOCK_SZ 256
227 # endif
228 #endif
229
230 static spinlock_t *rt_hash_locks;
231 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
232
233 static __init void rt_hash_lock_init(void)
234 {
235 int i;
236
237 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
238 GFP_KERNEL);
239 if (!rt_hash_locks)
240 panic("IP: failed to allocate rt_hash_locks\n");
241
242 for (i = 0; i < RT_HASH_LOCK_SZ; i++)
243 spin_lock_init(&rt_hash_locks[i]);
244 }
245 #else
246 # define rt_hash_lock_addr(slot) NULL
247
248 static inline void rt_hash_lock_init(void)
249 {
250 }
251 #endif
252
253 static struct rt_hash_bucket *rt_hash_table __read_mostly;
254 static unsigned rt_hash_mask __read_mostly;
255 static unsigned int rt_hash_log __read_mostly;
256 static atomic_t rt_genid __read_mostly;
257
258 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
259 #define RT_CACHE_STAT_INC(field) \
260 (__raw_get_cpu_var(rt_cache_stat).field++)
261
262 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx)
263 {
264 return jhash_3words((__force u32)(__be32)(daddr),
265 (__force u32)(__be32)(saddr),
266 idx, atomic_read(&rt_genid))
267 & rt_hash_mask;
268 }
269
270 #ifdef CONFIG_PROC_FS
271 struct rt_cache_iter_state {
272 struct seq_net_private p;
273 int bucket;
274 int genid;
275 };
276
277 static struct rtable *rt_cache_get_first(struct seq_file *seq)
278 {
279 struct rt_cache_iter_state *st = seq->private;
280 struct rtable *r = NULL;
281
282 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
283 rcu_read_lock_bh();
284 r = rcu_dereference(rt_hash_table[st->bucket].chain);
285 while (r) {
286 if (dev_net(r->u.dst.dev) == seq_file_net(seq) &&
287 r->rt_genid == st->genid)
288 return r;
289 r = rcu_dereference(r->u.dst.rt_next);
290 }
291 rcu_read_unlock_bh();
292 }
293 return r;
294 }
295
296 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
297 struct rtable *r)
298 {
299 struct rt_cache_iter_state *st = seq->private;
300 r = r->u.dst.rt_next;
301 while (!r) {
302 rcu_read_unlock_bh();
303 if (--st->bucket < 0)
304 break;
305 rcu_read_lock_bh();
306 r = rt_hash_table[st->bucket].chain;
307 }
308 return rcu_dereference(r);
309 }
310
311 static struct rtable *rt_cache_get_next(struct seq_file *seq,
312 struct rtable *r)
313 {
314 struct rt_cache_iter_state *st = seq->private;
315 while ((r = __rt_cache_get_next(seq, r)) != NULL) {
316 if (dev_net(r->u.dst.dev) != seq_file_net(seq))
317 continue;
318 if (r->rt_genid == st->genid)
319 break;
320 }
321 return r;
322 }
323
324 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
325 {
326 struct rtable *r = rt_cache_get_first(seq);
327
328 if (r)
329 while (pos && (r = rt_cache_get_next(seq, r)))
330 --pos;
331 return pos ? NULL : r;
332 }
333
334 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
335 {
336 struct rt_cache_iter_state *st = seq->private;
337 if (*pos)
338 return rt_cache_get_idx(seq, *pos - 1);
339 st->genid = atomic_read(&rt_genid);
340 return SEQ_START_TOKEN;
341 }
342
343 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
344 {
345 struct rtable *r;
346
347 if (v == SEQ_START_TOKEN)
348 r = rt_cache_get_first(seq);
349 else
350 r = rt_cache_get_next(seq, v);
351 ++*pos;
352 return r;
353 }
354
355 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
356 {
357 if (v && v != SEQ_START_TOKEN)
358 rcu_read_unlock_bh();
359 }
360
361 static int rt_cache_seq_show(struct seq_file *seq, void *v)
362 {
363 if (v == SEQ_START_TOKEN)
364 seq_printf(seq, "%-127s\n",
365 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
366 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
367 "HHUptod\tSpecDst");
368 else {
369 struct rtable *r = v;
370 int len;
371
372 seq_printf(seq, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
373 "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
374 r->u.dst.dev ? r->u.dst.dev->name : "*",
375 (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
376 r->rt_flags, atomic_read(&r->u.dst.__refcnt),
377 r->u.dst.__use, 0, (unsigned long)r->rt_src,
378 (dst_metric(&r->u.dst, RTAX_ADVMSS) ?
379 (int)dst_metric(&r->u.dst, RTAX_ADVMSS) + 40 : 0),
380 dst_metric(&r->u.dst, RTAX_WINDOW),
381 (int)((dst_metric(&r->u.dst, RTAX_RTT) >> 3) +
382 dst_metric(&r->u.dst, RTAX_RTTVAR)),
383 r->fl.fl4_tos,
384 r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
385 r->u.dst.hh ? (r->u.dst.hh->hh_output ==
386 dev_queue_xmit) : 0,
387 r->rt_spec_dst, &len);
388
389 seq_printf(seq, "%*s\n", 127 - len, "");
390 }
391 return 0;
392 }
393
394 static const struct seq_operations rt_cache_seq_ops = {
395 .start = rt_cache_seq_start,
396 .next = rt_cache_seq_next,
397 .stop = rt_cache_seq_stop,
398 .show = rt_cache_seq_show,
399 };
400
401 static int rt_cache_seq_open(struct inode *inode, struct file *file)
402 {
403 return seq_open_net(inode, file, &rt_cache_seq_ops,
404 sizeof(struct rt_cache_iter_state));
405 }
406
407 static const struct file_operations rt_cache_seq_fops = {
408 .owner = THIS_MODULE,
409 .open = rt_cache_seq_open,
410 .read = seq_read,
411 .llseek = seq_lseek,
412 .release = seq_release_net,
413 };
414
415
416 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
417 {
418 int cpu;
419
420 if (*pos == 0)
421 return SEQ_START_TOKEN;
422
423 for (cpu = *pos-1; cpu < NR_CPUS; ++cpu) {
424 if (!cpu_possible(cpu))
425 continue;
426 *pos = cpu+1;
427 return &per_cpu(rt_cache_stat, cpu);
428 }
429 return NULL;
430 }
431
432 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
433 {
434 int cpu;
435
436 for (cpu = *pos; cpu < NR_CPUS; ++cpu) {
437 if (!cpu_possible(cpu))
438 continue;
439 *pos = cpu+1;
440 return &per_cpu(rt_cache_stat, cpu);
441 }
442 return NULL;
443
444 }
445
446 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
447 {
448
449 }
450
451 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
452 {
453 struct rt_cache_stat *st = v;
454
455 if (v == SEQ_START_TOKEN) {
456 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");
457 return 0;
458 }
459
460 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
461 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
462 atomic_read(&ipv4_dst_ops.entries),
463 st->in_hit,
464 st->in_slow_tot,
465 st->in_slow_mc,
466 st->in_no_route,
467 st->in_brd,
468 st->in_martian_dst,
469 st->in_martian_src,
470
471 st->out_hit,
472 st->out_slow_tot,
473 st->out_slow_mc,
474
475 st->gc_total,
476 st->gc_ignored,
477 st->gc_goal_miss,
478 st->gc_dst_overflow,
479 st->in_hlist_search,
480 st->out_hlist_search
481 );
482 return 0;
483 }
484
485 static const struct seq_operations rt_cpu_seq_ops = {
486 .start = rt_cpu_seq_start,
487 .next = rt_cpu_seq_next,
488 .stop = rt_cpu_seq_stop,
489 .show = rt_cpu_seq_show,
490 };
491
492
493 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
494 {
495 return seq_open(file, &rt_cpu_seq_ops);
496 }
497
498 static const struct file_operations rt_cpu_seq_fops = {
499 .owner = THIS_MODULE,
500 .open = rt_cpu_seq_open,
501 .read = seq_read,
502 .llseek = seq_lseek,
503 .release = seq_release,
504 };
505
506 #ifdef CONFIG_NET_CLS_ROUTE
507 static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
508 int length, int *eof, void *data)
509 {
510 unsigned int i;
511
512 if ((offset & 3) || (length & 3))
513 return -EIO;
514
515 if (offset >= sizeof(struct ip_rt_acct) * 256) {
516 *eof = 1;
517 return 0;
518 }
519
520 if (offset + length >= sizeof(struct ip_rt_acct) * 256) {
521 length = sizeof(struct ip_rt_acct) * 256 - offset;
522 *eof = 1;
523 }
524
525 offset /= sizeof(u32);
526
527 if (length > 0) {
528 u32 *dst = (u32 *) buffer;
529
530 *start = buffer;
531 memset(dst, 0, length);
532
533 for_each_possible_cpu(i) {
534 unsigned int j;
535 u32 *src;
536
537 src = ((u32 *) per_cpu_ptr(ip_rt_acct, i)) + offset;
538 for (j = 0; j < length/4; j++)
539 dst[j] += src[j];
540 }
541 }
542 return length;
543 }
544 #endif
545
546 static int __net_init ip_rt_do_proc_init(struct net *net)
547 {
548 struct proc_dir_entry *pde;
549
550 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
551 &rt_cache_seq_fops);
552 if (!pde)
553 goto err1;
554
555 pde = proc_create("rt_cache", S_IRUGO,
556 net->proc_net_stat, &rt_cpu_seq_fops);
557 if (!pde)
558 goto err2;
559
560 #ifdef CONFIG_NET_CLS_ROUTE
561 pde = create_proc_read_entry("rt_acct", 0, net->proc_net,
562 ip_rt_acct_read, NULL);
563 if (!pde)
564 goto err3;
565 #endif
566 return 0;
567
568 #ifdef CONFIG_NET_CLS_ROUTE
569 err3:
570 remove_proc_entry("rt_cache", net->proc_net_stat);
571 #endif
572 err2:
573 remove_proc_entry("rt_cache", net->proc_net);
574 err1:
575 return -ENOMEM;
576 }
577
578 static void __net_exit ip_rt_do_proc_exit(struct net *net)
579 {
580 remove_proc_entry("rt_cache", net->proc_net_stat);
581 remove_proc_entry("rt_cache", net->proc_net);
582 remove_proc_entry("rt_acct", net->proc_net);
583 }
584
585 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
586 .init = ip_rt_do_proc_init,
587 .exit = ip_rt_do_proc_exit,
588 };
589
590 static int __init ip_rt_proc_init(void)
591 {
592 return register_pernet_subsys(&ip_rt_proc_ops);
593 }
594
595 #else
596 static inline int ip_rt_proc_init(void)
597 {
598 return 0;
599 }
600 #endif /* CONFIG_PROC_FS */
601
602 static inline void rt_free(struct rtable *rt)
603 {
604 call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
605 }
606
607 static inline void rt_drop(struct rtable *rt)
608 {
609 ip_rt_put(rt);
610 call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
611 }
612
613 static inline int rt_fast_clean(struct rtable *rth)
614 {
615 /* Kill broadcast/multicast entries very aggresively, if they
616 collide in hash table with more useful entries */
617 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
618 rth->fl.iif && rth->u.dst.rt_next;
619 }
620
621 static inline int rt_valuable(struct rtable *rth)
622 {
623 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
624 rth->u.dst.expires;
625 }
626
627 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
628 {
629 unsigned long age;
630 int ret = 0;
631
632 if (atomic_read(&rth->u.dst.__refcnt))
633 goto out;
634
635 ret = 1;
636 if (rth->u.dst.expires &&
637 time_after_eq(jiffies, rth->u.dst.expires))
638 goto out;
639
640 age = jiffies - rth->u.dst.lastuse;
641 ret = 0;
642 if ((age <= tmo1 && !rt_fast_clean(rth)) ||
643 (age <= tmo2 && rt_valuable(rth)))
644 goto out;
645 ret = 1;
646 out: return ret;
647 }
648
649 /* Bits of score are:
650 * 31: very valuable
651 * 30: not quite useless
652 * 29..0: usage counter
653 */
654 static inline u32 rt_score(struct rtable *rt)
655 {
656 u32 score = jiffies - rt->u.dst.lastuse;
657
658 score = ~score & ~(3<<30);
659
660 if (rt_valuable(rt))
661 score |= (1<<31);
662
663 if (!rt->fl.iif ||
664 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
665 score |= (1<<30);
666
667 return score;
668 }
669
670 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
671 {
672 return ((__force u32)((fl1->nl_u.ip4_u.daddr ^ fl2->nl_u.ip4_u.daddr) |
673 (fl1->nl_u.ip4_u.saddr ^ fl2->nl_u.ip4_u.saddr)) |
674 (fl1->mark ^ fl2->mark) |
675 (*(u16 *)&fl1->nl_u.ip4_u.tos ^
676 *(u16 *)&fl2->nl_u.ip4_u.tos) |
677 (fl1->oif ^ fl2->oif) |
678 (fl1->iif ^ fl2->iif)) == 0;
679 }
680
681 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
682 {
683 return dev_net(rt1->u.dst.dev) == dev_net(rt2->u.dst.dev);
684 }
685
686 /*
687 * Perform a full scan of hash table and free all entries.
688 * Can be called by a softirq or a process.
689 * In the later case, we want to be reschedule if necessary
690 */
691 static void rt_do_flush(int process_context)
692 {
693 unsigned int i;
694 struct rtable *rth, *next;
695
696 for (i = 0; i <= rt_hash_mask; i++) {
697 if (process_context && need_resched())
698 cond_resched();
699 rth = rt_hash_table[i].chain;
700 if (!rth)
701 continue;
702
703 spin_lock_bh(rt_hash_lock_addr(i));
704 rth = rt_hash_table[i].chain;
705 rt_hash_table[i].chain = NULL;
706 spin_unlock_bh(rt_hash_lock_addr(i));
707
708 for (; rth; rth = next) {
709 next = rth->u.dst.rt_next;
710 rt_free(rth);
711 }
712 }
713 }
714
715 static void rt_check_expire(void)
716 {
717 static unsigned int rover;
718 unsigned int i = rover, goal;
719 struct rtable *rth, **rthp;
720 u64 mult;
721
722 mult = ((u64)ip_rt_gc_interval) << rt_hash_log;
723 if (ip_rt_gc_timeout > 1)
724 do_div(mult, ip_rt_gc_timeout);
725 goal = (unsigned int)mult;
726 if (goal > rt_hash_mask)
727 goal = rt_hash_mask + 1;
728 for (; goal > 0; goal--) {
729 unsigned long tmo = ip_rt_gc_timeout;
730
731 i = (i + 1) & rt_hash_mask;
732 rthp = &rt_hash_table[i].chain;
733
734 if (need_resched())
735 cond_resched();
736
737 if (*rthp == NULL)
738 continue;
739 spin_lock_bh(rt_hash_lock_addr(i));
740 while ((rth = *rthp) != NULL) {
741 if (rth->rt_genid != atomic_read(&rt_genid)) {
742 *rthp = rth->u.dst.rt_next;
743 rt_free(rth);
744 continue;
745 }
746 if (rth->u.dst.expires) {
747 /* Entry is expired even if it is in use */
748 if (time_before_eq(jiffies, rth->u.dst.expires)) {
749 tmo >>= 1;
750 rthp = &rth->u.dst.rt_next;
751 continue;
752 }
753 } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
754 tmo >>= 1;
755 rthp = &rth->u.dst.rt_next;
756 continue;
757 }
758
759 /* Cleanup aged off entries. */
760 *rthp = rth->u.dst.rt_next;
761 rt_free(rth);
762 }
763 spin_unlock_bh(rt_hash_lock_addr(i));
764 }
765 rover = i;
766 }
767
768 /*
769 * rt_worker_func() is run in process context.
770 * we call rt_check_expire() to scan part of the hash table
771 */
772 static void rt_worker_func(struct work_struct *work)
773 {
774 rt_check_expire();
775 schedule_delayed_work(&expires_work, ip_rt_gc_interval);
776 }
777
778 /*
779 * Pertubation of rt_genid by a small quantity [1..256]
780 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
781 * many times (2^24) without giving recent rt_genid.
782 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
783 */
784 static void rt_cache_invalidate(void)
785 {
786 unsigned char shuffle;
787
788 get_random_bytes(&shuffle, sizeof(shuffle));
789 atomic_add(shuffle + 1U, &rt_genid);
790 }
791
792 /*
793 * delay < 0 : invalidate cache (fast : entries will be deleted later)
794 * delay >= 0 : invalidate & flush cache (can be long)
795 */
796 void rt_cache_flush(int delay)
797 {
798 rt_cache_invalidate();
799 if (delay >= 0)
800 rt_do_flush(!in_softirq());
801 }
802
803 /*
804 * We change rt_genid and let gc do the cleanup
805 */
806 static void rt_secret_rebuild(unsigned long dummy)
807 {
808 rt_cache_invalidate();
809 mod_timer(&rt_secret_timer, jiffies + ip_rt_secret_interval);
810 }
811
812 /*
813 Short description of GC goals.
814
815 We want to build algorithm, which will keep routing cache
816 at some equilibrium point, when number of aged off entries
817 is kept approximately equal to newly generated ones.
818
819 Current expiration strength is variable "expire".
820 We try to adjust it dynamically, so that if networking
821 is idle expires is large enough to keep enough of warm entries,
822 and when load increases it reduces to limit cache size.
823 */
824
825 static int rt_garbage_collect(struct dst_ops *ops)
826 {
827 static unsigned long expire = RT_GC_TIMEOUT;
828 static unsigned long last_gc;
829 static int rover;
830 static int equilibrium;
831 struct rtable *rth, **rthp;
832 unsigned long now = jiffies;
833 int goal;
834
835 /*
836 * Garbage collection is pretty expensive,
837 * do not make it too frequently.
838 */
839
840 RT_CACHE_STAT_INC(gc_total);
841
842 if (now - last_gc < ip_rt_gc_min_interval &&
843 atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) {
844 RT_CACHE_STAT_INC(gc_ignored);
845 goto out;
846 }
847
848 /* Calculate number of entries, which we want to expire now. */
849 goal = atomic_read(&ipv4_dst_ops.entries) -
850 (ip_rt_gc_elasticity << rt_hash_log);
851 if (goal <= 0) {
852 if (equilibrium < ipv4_dst_ops.gc_thresh)
853 equilibrium = ipv4_dst_ops.gc_thresh;
854 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
855 if (goal > 0) {
856 equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
857 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
858 }
859 } else {
860 /* We are in dangerous area. Try to reduce cache really
861 * aggressively.
862 */
863 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
864 equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
865 }
866
867 if (now - last_gc >= ip_rt_gc_min_interval)
868 last_gc = now;
869
870 if (goal <= 0) {
871 equilibrium += goal;
872 goto work_done;
873 }
874
875 do {
876 int i, k;
877
878 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
879 unsigned long tmo = expire;
880
881 k = (k + 1) & rt_hash_mask;
882 rthp = &rt_hash_table[k].chain;
883 spin_lock_bh(rt_hash_lock_addr(k));
884 while ((rth = *rthp) != NULL) {
885 if (rth->rt_genid == atomic_read(&rt_genid) &&
886 !rt_may_expire(rth, tmo, expire)) {
887 tmo >>= 1;
888 rthp = &rth->u.dst.rt_next;
889 continue;
890 }
891 *rthp = rth->u.dst.rt_next;
892 rt_free(rth);
893 goal--;
894 }
895 spin_unlock_bh(rt_hash_lock_addr(k));
896 if (goal <= 0)
897 break;
898 }
899 rover = k;
900
901 if (goal <= 0)
902 goto work_done;
903
904 /* Goal is not achieved. We stop process if:
905
906 - if expire reduced to zero. Otherwise, expire is halfed.
907 - if table is not full.
908 - if we are called from interrupt.
909 - jiffies check is just fallback/debug loop breaker.
910 We will not spin here for long time in any case.
911 */
912
913 RT_CACHE_STAT_INC(gc_goal_miss);
914
915 if (expire == 0)
916 break;
917
918 expire >>= 1;
919 #if RT_CACHE_DEBUG >= 2
920 printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
921 atomic_read(&ipv4_dst_ops.entries), goal, i);
922 #endif
923
924 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
925 goto out;
926 } while (!in_softirq() && time_before_eq(jiffies, now));
927
928 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
929 goto out;
930 if (net_ratelimit())
931 printk(KERN_WARNING "dst cache overflow\n");
932 RT_CACHE_STAT_INC(gc_dst_overflow);
933 return 1;
934
935 work_done:
936 expire += ip_rt_gc_min_interval;
937 if (expire > ip_rt_gc_timeout ||
938 atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh)
939 expire = ip_rt_gc_timeout;
940 #if RT_CACHE_DEBUG >= 2
941 printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
942 atomic_read(&ipv4_dst_ops.entries), goal, rover);
943 #endif
944 out: return 0;
945 }
946
947 static int rt_intern_hash(unsigned hash, struct rtable *rt, struct rtable **rp)
948 {
949 struct rtable *rth, **rthp;
950 unsigned long now;
951 struct rtable *cand, **candp;
952 u32 min_score;
953 int chain_length;
954 int attempts = !in_softirq();
955
956 restart:
957 chain_length = 0;
958 min_score = ~(u32)0;
959 cand = NULL;
960 candp = NULL;
961 now = jiffies;
962
963 rthp = &rt_hash_table[hash].chain;
964
965 spin_lock_bh(rt_hash_lock_addr(hash));
966 while ((rth = *rthp) != NULL) {
967 if (rth->rt_genid != atomic_read(&rt_genid)) {
968 *rthp = rth->u.dst.rt_next;
969 rt_free(rth);
970 continue;
971 }
972 if (compare_keys(&rth->fl, &rt->fl) && compare_netns(rth, rt)) {
973 /* Put it first */
974 *rthp = rth->u.dst.rt_next;
975 /*
976 * Since lookup is lockfree, the deletion
977 * must be visible to another weakly ordered CPU before
978 * the insertion at the start of the hash chain.
979 */
980 rcu_assign_pointer(rth->u.dst.rt_next,
981 rt_hash_table[hash].chain);
982 /*
983 * Since lookup is lockfree, the update writes
984 * must be ordered for consistency on SMP.
985 */
986 rcu_assign_pointer(rt_hash_table[hash].chain, rth);
987
988 dst_use(&rth->u.dst, now);
989 spin_unlock_bh(rt_hash_lock_addr(hash));
990
991 rt_drop(rt);
992 *rp = rth;
993 return 0;
994 }
995
996 if (!atomic_read(&rth->u.dst.__refcnt)) {
997 u32 score = rt_score(rth);
998
999 if (score <= min_score) {
1000 cand = rth;
1001 candp = rthp;
1002 min_score = score;
1003 }
1004 }
1005
1006 chain_length++;
1007
1008 rthp = &rth->u.dst.rt_next;
1009 }
1010
1011 if (cand) {
1012 /* ip_rt_gc_elasticity used to be average length of chain
1013 * length, when exceeded gc becomes really aggressive.
1014 *
1015 * The second limit is less certain. At the moment it allows
1016 * only 2 entries per bucket. We will see.
1017 */
1018 if (chain_length > ip_rt_gc_elasticity) {
1019 *candp = cand->u.dst.rt_next;
1020 rt_free(cand);
1021 }
1022 }
1023
1024 /* Try to bind route to arp only if it is output
1025 route or unicast forwarding path.
1026 */
1027 if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
1028 int err = arp_bind_neighbour(&rt->u.dst);
1029 if (err) {
1030 spin_unlock_bh(rt_hash_lock_addr(hash));
1031
1032 if (err != -ENOBUFS) {
1033 rt_drop(rt);
1034 return err;
1035 }
1036
1037 /* Neighbour tables are full and nothing
1038 can be released. Try to shrink route cache,
1039 it is most likely it holds some neighbour records.
1040 */
1041 if (attempts-- > 0) {
1042 int saved_elasticity = ip_rt_gc_elasticity;
1043 int saved_int = ip_rt_gc_min_interval;
1044 ip_rt_gc_elasticity = 1;
1045 ip_rt_gc_min_interval = 0;
1046 rt_garbage_collect(&ipv4_dst_ops);
1047 ip_rt_gc_min_interval = saved_int;
1048 ip_rt_gc_elasticity = saved_elasticity;
1049 goto restart;
1050 }
1051
1052 if (net_ratelimit())
1053 printk(KERN_WARNING "Neighbour table overflow.\n");
1054 rt_drop(rt);
1055 return -ENOBUFS;
1056 }
1057 }
1058
1059 rt->u.dst.rt_next = rt_hash_table[hash].chain;
1060 #if RT_CACHE_DEBUG >= 2
1061 if (rt->u.dst.rt_next) {
1062 struct rtable *trt;
1063 printk(KERN_DEBUG "rt_cache @%02x: " NIPQUAD_FMT, hash,
1064 NIPQUAD(rt->rt_dst));
1065 for (trt = rt->u.dst.rt_next; trt; trt = trt->u.dst.rt_next)
1066 printk(" . " NIPQUAD_FMT, NIPQUAD(trt->rt_dst));
1067 printk("\n");
1068 }
1069 #endif
1070 rt_hash_table[hash].chain = rt;
1071 spin_unlock_bh(rt_hash_lock_addr(hash));
1072 *rp = rt;
1073 return 0;
1074 }
1075
1076 void rt_bind_peer(struct rtable *rt, int create)
1077 {
1078 static DEFINE_SPINLOCK(rt_peer_lock);
1079 struct inet_peer *peer;
1080
1081 peer = inet_getpeer(rt->rt_dst, create);
1082
1083 spin_lock_bh(&rt_peer_lock);
1084 if (rt->peer == NULL) {
1085 rt->peer = peer;
1086 peer = NULL;
1087 }
1088 spin_unlock_bh(&rt_peer_lock);
1089 if (peer)
1090 inet_putpeer(peer);
1091 }
1092
1093 /*
1094 * Peer allocation may fail only in serious out-of-memory conditions. However
1095 * we still can generate some output.
1096 * Random ID selection looks a bit dangerous because we have no chances to
1097 * select ID being unique in a reasonable period of time.
1098 * But broken packet identifier may be better than no packet at all.
1099 */
1100 static void ip_select_fb_ident(struct iphdr *iph)
1101 {
1102 static DEFINE_SPINLOCK(ip_fb_id_lock);
1103 static u32 ip_fallback_id;
1104 u32 salt;
1105
1106 spin_lock_bh(&ip_fb_id_lock);
1107 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1108 iph->id = htons(salt & 0xFFFF);
1109 ip_fallback_id = salt;
1110 spin_unlock_bh(&ip_fb_id_lock);
1111 }
1112
1113 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1114 {
1115 struct rtable *rt = (struct rtable *) dst;
1116
1117 if (rt) {
1118 if (rt->peer == NULL)
1119 rt_bind_peer(rt, 1);
1120
1121 /* If peer is attached to destination, it is never detached,
1122 so that we need not to grab a lock to dereference it.
1123 */
1124 if (rt->peer) {
1125 iph->id = htons(inet_getid(rt->peer, more));
1126 return;
1127 }
1128 } else
1129 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1130 __builtin_return_address(0));
1131
1132 ip_select_fb_ident(iph);
1133 }
1134
1135 static void rt_del(unsigned hash, struct rtable *rt)
1136 {
1137 struct rtable **rthp, *aux;
1138
1139 rthp = &rt_hash_table[hash].chain;
1140 spin_lock_bh(rt_hash_lock_addr(hash));
1141 ip_rt_put(rt);
1142 while ((aux = *rthp) != NULL) {
1143 if (aux == rt || (aux->rt_genid != atomic_read(&rt_genid))) {
1144 *rthp = aux->u.dst.rt_next;
1145 rt_free(aux);
1146 continue;
1147 }
1148 rthp = &aux->u.dst.rt_next;
1149 }
1150 spin_unlock_bh(rt_hash_lock_addr(hash));
1151 }
1152
1153 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1154 __be32 saddr, struct net_device *dev)
1155 {
1156 int i, k;
1157 struct in_device *in_dev = in_dev_get(dev);
1158 struct rtable *rth, **rthp;
1159 __be32 skeys[2] = { saddr, 0 };
1160 int ikeys[2] = { dev->ifindex, 0 };
1161 struct netevent_redirect netevent;
1162 struct net *net;
1163
1164 if (!in_dev)
1165 return;
1166
1167 net = dev_net(dev);
1168 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
1169 || ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw)
1170 || ipv4_is_zeronet(new_gw))
1171 goto reject_redirect;
1172
1173 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1174 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1175 goto reject_redirect;
1176 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1177 goto reject_redirect;
1178 } else {
1179 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1180 goto reject_redirect;
1181 }
1182
1183 for (i = 0; i < 2; i++) {
1184 for (k = 0; k < 2; k++) {
1185 unsigned hash = rt_hash(daddr, skeys[i], ikeys[k]);
1186
1187 rthp=&rt_hash_table[hash].chain;
1188
1189 rcu_read_lock();
1190 while ((rth = rcu_dereference(*rthp)) != NULL) {
1191 struct rtable *rt;
1192
1193 if (rth->fl.fl4_dst != daddr ||
1194 rth->fl.fl4_src != skeys[i] ||
1195 rth->fl.oif != ikeys[k] ||
1196 rth->fl.iif != 0 ||
1197 rth->rt_genid != atomic_read(&rt_genid) ||
1198 !net_eq(dev_net(rth->u.dst.dev), net)) {
1199 rthp = &rth->u.dst.rt_next;
1200 continue;
1201 }
1202
1203 if (rth->rt_dst != daddr ||
1204 rth->rt_src != saddr ||
1205 rth->u.dst.error ||
1206 rth->rt_gateway != old_gw ||
1207 rth->u.dst.dev != dev)
1208 break;
1209
1210 dst_hold(&rth->u.dst);
1211 rcu_read_unlock();
1212
1213 rt = dst_alloc(&ipv4_dst_ops);
1214 if (rt == NULL) {
1215 ip_rt_put(rth);
1216 in_dev_put(in_dev);
1217 return;
1218 }
1219
1220 /* Copy all the information. */
1221 *rt = *rth;
1222 INIT_RCU_HEAD(&rt->u.dst.rcu_head);
1223 rt->u.dst.__use = 1;
1224 atomic_set(&rt->u.dst.__refcnt, 1);
1225 rt->u.dst.child = NULL;
1226 if (rt->u.dst.dev)
1227 dev_hold(rt->u.dst.dev);
1228 if (rt->idev)
1229 in_dev_hold(rt->idev);
1230 rt->u.dst.obsolete = 0;
1231 rt->u.dst.lastuse = jiffies;
1232 rt->u.dst.path = &rt->u.dst;
1233 rt->u.dst.neighbour = NULL;
1234 rt->u.dst.hh = NULL;
1235 rt->u.dst.xfrm = NULL;
1236 rt->rt_genid = atomic_read(&rt_genid);
1237 rt->rt_flags |= RTCF_REDIRECTED;
1238
1239 /* Gateway is different ... */
1240 rt->rt_gateway = new_gw;
1241
1242 /* Redirect received -> path was valid */
1243 dst_confirm(&rth->u.dst);
1244
1245 if (rt->peer)
1246 atomic_inc(&rt->peer->refcnt);
1247
1248 if (arp_bind_neighbour(&rt->u.dst) ||
1249 !(rt->u.dst.neighbour->nud_state &
1250 NUD_VALID)) {
1251 if (rt->u.dst.neighbour)
1252 neigh_event_send(rt->u.dst.neighbour, NULL);
1253 ip_rt_put(rth);
1254 rt_drop(rt);
1255 goto do_next;
1256 }
1257
1258 netevent.old = &rth->u.dst;
1259 netevent.new = &rt->u.dst;
1260 call_netevent_notifiers(NETEVENT_REDIRECT,
1261 &netevent);
1262
1263 rt_del(hash, rth);
1264 if (!rt_intern_hash(hash, rt, &rt))
1265 ip_rt_put(rt);
1266 goto do_next;
1267 }
1268 rcu_read_unlock();
1269 do_next:
1270 ;
1271 }
1272 }
1273 in_dev_put(in_dev);
1274 return;
1275
1276 reject_redirect:
1277 #ifdef CONFIG_IP_ROUTE_VERBOSE
1278 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1279 printk(KERN_INFO "Redirect from " NIPQUAD_FMT " on %s about "
1280 NIPQUAD_FMT " ignored.\n"
1281 " Advised path = " NIPQUAD_FMT " -> " NIPQUAD_FMT "\n",
1282 NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw),
1283 NIPQUAD(saddr), NIPQUAD(daddr));
1284 #endif
1285 in_dev_put(in_dev);
1286 }
1287
1288 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1289 {
1290 struct rtable *rt = (struct rtable *)dst;
1291 struct dst_entry *ret = dst;
1292
1293 if (rt) {
1294 if (dst->obsolete) {
1295 ip_rt_put(rt);
1296 ret = NULL;
1297 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
1298 rt->u.dst.expires) {
1299 unsigned hash = rt_hash(rt->fl.fl4_dst, rt->fl.fl4_src,
1300 rt->fl.oif);
1301 #if RT_CACHE_DEBUG >= 1
1302 printk(KERN_DEBUG "ipv4_negative_advice: redirect to "
1303 NIPQUAD_FMT "/%02x dropped\n",
1304 NIPQUAD(rt->rt_dst), rt->fl.fl4_tos);
1305 #endif
1306 rt_del(hash, rt);
1307 ret = NULL;
1308 }
1309 }
1310 return ret;
1311 }
1312
1313 /*
1314 * Algorithm:
1315 * 1. The first ip_rt_redirect_number redirects are sent
1316 * with exponential backoff, then we stop sending them at all,
1317 * assuming that the host ignores our redirects.
1318 * 2. If we did not see packets requiring redirects
1319 * during ip_rt_redirect_silence, we assume that the host
1320 * forgot redirected route and start to send redirects again.
1321 *
1322 * This algorithm is much cheaper and more intelligent than dumb load limiting
1323 * in icmp.c.
1324 *
1325 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1326 * and "frag. need" (breaks PMTU discovery) in icmp.c.
1327 */
1328
1329 void ip_rt_send_redirect(struct sk_buff *skb)
1330 {
1331 struct rtable *rt = skb->rtable;
1332 struct in_device *in_dev = in_dev_get(rt->u.dst.dev);
1333
1334 if (!in_dev)
1335 return;
1336
1337 if (!IN_DEV_TX_REDIRECTS(in_dev))
1338 goto out;
1339
1340 /* No redirected packets during ip_rt_redirect_silence;
1341 * reset the algorithm.
1342 */
1343 if (time_after(jiffies, rt->u.dst.rate_last + ip_rt_redirect_silence))
1344 rt->u.dst.rate_tokens = 0;
1345
1346 /* Too many ignored redirects; do not send anything
1347 * set u.dst.rate_last to the last seen redirected packet.
1348 */
1349 if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) {
1350 rt->u.dst.rate_last = jiffies;
1351 goto out;
1352 }
1353
1354 /* Check for load limit; set rate_last to the latest sent
1355 * redirect.
1356 */
1357 if (rt->u.dst.rate_tokens == 0 ||
1358 time_after(jiffies,
1359 (rt->u.dst.rate_last +
1360 (ip_rt_redirect_load << rt->u.dst.rate_tokens)))) {
1361 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1362 rt->u.dst.rate_last = jiffies;
1363 ++rt->u.dst.rate_tokens;
1364 #ifdef CONFIG_IP_ROUTE_VERBOSE
1365 if (IN_DEV_LOG_MARTIANS(in_dev) &&
1366 rt->u.dst.rate_tokens == ip_rt_redirect_number &&
1367 net_ratelimit())
1368 printk(KERN_WARNING "host " NIPQUAD_FMT "/if%d ignores "
1369 "redirects for " NIPQUAD_FMT " to " NIPQUAD_FMT ".\n",
1370 NIPQUAD(rt->rt_src), rt->rt_iif,
1371 NIPQUAD(rt->rt_dst), NIPQUAD(rt->rt_gateway));
1372 #endif
1373 }
1374 out:
1375 in_dev_put(in_dev);
1376 }
1377
1378 static int ip_error(struct sk_buff *skb)
1379 {
1380 struct rtable *rt = skb->rtable;
1381 unsigned long now;
1382 int code;
1383
1384 switch (rt->u.dst.error) {
1385 case EINVAL:
1386 default:
1387 goto out;
1388 case EHOSTUNREACH:
1389 code = ICMP_HOST_UNREACH;
1390 break;
1391 case ENETUNREACH:
1392 code = ICMP_NET_UNREACH;
1393 IP_INC_STATS_BH(IPSTATS_MIB_INNOROUTES);
1394 break;
1395 case EACCES:
1396 code = ICMP_PKT_FILTERED;
1397 break;
1398 }
1399
1400 now = jiffies;
1401 rt->u.dst.rate_tokens += now - rt->u.dst.rate_last;
1402 if (rt->u.dst.rate_tokens > ip_rt_error_burst)
1403 rt->u.dst.rate_tokens = ip_rt_error_burst;
1404 rt->u.dst.rate_last = now;
1405 if (rt->u.dst.rate_tokens >= ip_rt_error_cost) {
1406 rt->u.dst.rate_tokens -= ip_rt_error_cost;
1407 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1408 }
1409
1410 out: kfree_skb(skb);
1411 return 0;
1412 }
1413
1414 /*
1415 * The last two values are not from the RFC but
1416 * are needed for AMPRnet AX.25 paths.
1417 */
1418
1419 static const unsigned short mtu_plateau[] =
1420 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1421
1422 static inline unsigned short guess_mtu(unsigned short old_mtu)
1423 {
1424 int i;
1425
1426 for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1427 if (old_mtu > mtu_plateau[i])
1428 return mtu_plateau[i];
1429 return 68;
1430 }
1431
1432 unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
1433 unsigned short new_mtu,
1434 struct net_device *dev)
1435 {
1436 int i, k;
1437 unsigned short old_mtu = ntohs(iph->tot_len);
1438 struct rtable *rth;
1439 int ikeys[2] = { dev->ifindex, 0 };
1440 __be32 skeys[2] = { iph->saddr, 0, };
1441 __be32 daddr = iph->daddr;
1442 unsigned short est_mtu = 0;
1443
1444 if (ipv4_config.no_pmtu_disc)
1445 return 0;
1446
1447 for (k = 0; k < 2; k++) {
1448 for (i = 0; i < 2; i++) {
1449 unsigned hash = rt_hash(daddr, skeys[i], ikeys[k]);
1450
1451 rcu_read_lock();
1452 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
1453 rth = rcu_dereference(rth->u.dst.rt_next)) {
1454 unsigned short mtu = new_mtu;
1455
1456 if (rth->fl.fl4_dst != daddr ||
1457 rth->fl.fl4_src != skeys[i] ||
1458 rth->rt_dst != daddr ||
1459 rth->rt_src != iph->saddr ||
1460 rth->fl.oif != ikeys[k] ||
1461 rth->fl.iif != 0 ||
1462 dst_metric_locked(&rth->u.dst, RTAX_MTU) ||
1463 !net_eq(dev_net(rth->u.dst.dev), net) ||
1464 rth->rt_genid != atomic_read(&rt_genid))
1465 continue;
1466
1467 if (new_mtu < 68 || new_mtu >= old_mtu) {
1468
1469 /* BSD 4.2 compatibility hack :-( */
1470 if (mtu == 0 &&
1471 old_mtu >= dst_metric(&rth->u.dst, RTAX_MTU) &&
1472 old_mtu >= 68 + (iph->ihl << 2))
1473 old_mtu -= iph->ihl << 2;
1474
1475 mtu = guess_mtu(old_mtu);
1476 }
1477 if (mtu <= dst_metric(&rth->u.dst, RTAX_MTU)) {
1478 if (mtu < dst_metric(&rth->u.dst, RTAX_MTU)) {
1479 dst_confirm(&rth->u.dst);
1480 if (mtu < ip_rt_min_pmtu) {
1481 mtu = ip_rt_min_pmtu;
1482 rth->u.dst.metrics[RTAX_LOCK-1] |=
1483 (1 << RTAX_MTU);
1484 }
1485 rth->u.dst.metrics[RTAX_MTU-1] = mtu;
1486 dst_set_expires(&rth->u.dst,
1487 ip_rt_mtu_expires);
1488 }
1489 est_mtu = mtu;
1490 }
1491 }
1492 rcu_read_unlock();
1493 }
1494 }
1495 return est_mtu ? : new_mtu;
1496 }
1497
1498 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1499 {
1500 if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= 68 &&
1501 !(dst_metric_locked(dst, RTAX_MTU))) {
1502 if (mtu < ip_rt_min_pmtu) {
1503 mtu = ip_rt_min_pmtu;
1504 dst->metrics[RTAX_LOCK-1] |= (1 << RTAX_MTU);
1505 }
1506 dst->metrics[RTAX_MTU-1] = mtu;
1507 dst_set_expires(dst, ip_rt_mtu_expires);
1508 call_netevent_notifiers(NETEVENT_PMTU_UPDATE, dst);
1509 }
1510 }
1511
1512 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1513 {
1514 return NULL;
1515 }
1516
1517 static void ipv4_dst_destroy(struct dst_entry *dst)
1518 {
1519 struct rtable *rt = (struct rtable *) dst;
1520 struct inet_peer *peer = rt->peer;
1521 struct in_device *idev = rt->idev;
1522
1523 if (peer) {
1524 rt->peer = NULL;
1525 inet_putpeer(peer);
1526 }
1527
1528 if (idev) {
1529 rt->idev = NULL;
1530 in_dev_put(idev);
1531 }
1532 }
1533
1534 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
1535 int how)
1536 {
1537 struct rtable *rt = (struct rtable *) dst;
1538 struct in_device *idev = rt->idev;
1539 if (dev != dev_net(dev)->loopback_dev && idev && idev->dev == dev) {
1540 struct in_device *loopback_idev =
1541 in_dev_get(dev_net(dev)->loopback_dev);
1542 if (loopback_idev) {
1543 rt->idev = loopback_idev;
1544 in_dev_put(idev);
1545 }
1546 }
1547 }
1548
1549 static void ipv4_link_failure(struct sk_buff *skb)
1550 {
1551 struct rtable *rt;
1552
1553 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1554
1555 rt = skb->rtable;
1556 if (rt)
1557 dst_set_expires(&rt->u.dst, 0);
1558 }
1559
1560 static int ip_rt_bug(struct sk_buff *skb)
1561 {
1562 printk(KERN_DEBUG "ip_rt_bug: " NIPQUAD_FMT " -> " NIPQUAD_FMT ", %s\n",
1563 NIPQUAD(ip_hdr(skb)->saddr), NIPQUAD(ip_hdr(skb)->daddr),
1564 skb->dev ? skb->dev->name : "?");
1565 kfree_skb(skb);
1566 return 0;
1567 }
1568
1569 /*
1570 We do not cache source address of outgoing interface,
1571 because it is used only by IP RR, TS and SRR options,
1572 so that it out of fast path.
1573
1574 BTW remember: "addr" is allowed to be not aligned
1575 in IP options!
1576 */
1577
1578 void ip_rt_get_source(u8 *addr, struct rtable *rt)
1579 {
1580 __be32 src;
1581 struct fib_result res;
1582
1583 if (rt->fl.iif == 0)
1584 src = rt->rt_src;
1585 else if (fib_lookup(dev_net(rt->u.dst.dev), &rt->fl, &res) == 0) {
1586 src = FIB_RES_PREFSRC(res);
1587 fib_res_put(&res);
1588 } else
1589 src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway,
1590 RT_SCOPE_UNIVERSE);
1591 memcpy(addr, &src, 4);
1592 }
1593
1594 #ifdef CONFIG_NET_CLS_ROUTE
1595 static void set_class_tag(struct rtable *rt, u32 tag)
1596 {
1597 if (!(rt->u.dst.tclassid & 0xFFFF))
1598 rt->u.dst.tclassid |= tag & 0xFFFF;
1599 if (!(rt->u.dst.tclassid & 0xFFFF0000))
1600 rt->u.dst.tclassid |= tag & 0xFFFF0000;
1601 }
1602 #endif
1603
1604 static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
1605 {
1606 struct fib_info *fi = res->fi;
1607
1608 if (fi) {
1609 if (FIB_RES_GW(*res) &&
1610 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1611 rt->rt_gateway = FIB_RES_GW(*res);
1612 memcpy(rt->u.dst.metrics, fi->fib_metrics,
1613 sizeof(rt->u.dst.metrics));
1614 if (fi->fib_mtu == 0) {
1615 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
1616 if (dst_metric_locked(&rt->u.dst, RTAX_MTU) &&
1617 rt->rt_gateway != rt->rt_dst &&
1618 rt->u.dst.dev->mtu > 576)
1619 rt->u.dst.metrics[RTAX_MTU-1] = 576;
1620 }
1621 #ifdef CONFIG_NET_CLS_ROUTE
1622 rt->u.dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1623 #endif
1624 } else
1625 rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu;
1626
1627 if (dst_metric(&rt->u.dst, RTAX_HOPLIMIT) == 0)
1628 rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl;
1629 if (dst_metric(&rt->u.dst, RTAX_MTU) > IP_MAX_MTU)
1630 rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU;
1631 if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0)
1632 rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40,
1633 ip_rt_min_advmss);
1634 if (dst_metric(&rt->u.dst, RTAX_ADVMSS) > 65535 - 40)
1635 rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40;
1636
1637 #ifdef CONFIG_NET_CLS_ROUTE
1638 #ifdef CONFIG_IP_MULTIPLE_TABLES
1639 set_class_tag(rt, fib_rules_tclass(res));
1640 #endif
1641 set_class_tag(rt, itag);
1642 #endif
1643 rt->rt_type = res->type;
1644 }
1645
1646 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1647 u8 tos, struct net_device *dev, int our)
1648 {
1649 unsigned hash;
1650 struct rtable *rth;
1651 __be32 spec_dst;
1652 struct in_device *in_dev = in_dev_get(dev);
1653 u32 itag = 0;
1654
1655 /* Primary sanity checks. */
1656
1657 if (in_dev == NULL)
1658 return -EINVAL;
1659
1660 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1661 ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
1662 goto e_inval;
1663
1664 if (ipv4_is_zeronet(saddr)) {
1665 if (!ipv4_is_local_multicast(daddr))
1666 goto e_inval;
1667 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1668 } else if (fib_validate_source(saddr, 0, tos, 0,
1669 dev, &spec_dst, &itag) < 0)
1670 goto e_inval;
1671
1672 rth = dst_alloc(&ipv4_dst_ops);
1673 if (!rth)
1674 goto e_nobufs;
1675
1676 rth->u.dst.output= ip_rt_bug;
1677
1678 atomic_set(&rth->u.dst.__refcnt, 1);
1679 rth->u.dst.flags= DST_HOST;
1680 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
1681 rth->u.dst.flags |= DST_NOPOLICY;
1682 rth->fl.fl4_dst = daddr;
1683 rth->rt_dst = daddr;
1684 rth->fl.fl4_tos = tos;
1685 rth->fl.mark = skb->mark;
1686 rth->fl.fl4_src = saddr;
1687 rth->rt_src = saddr;
1688 #ifdef CONFIG_NET_CLS_ROUTE
1689 rth->u.dst.tclassid = itag;
1690 #endif
1691 rth->rt_iif =
1692 rth->fl.iif = dev->ifindex;
1693 rth->u.dst.dev = init_net.loopback_dev;
1694 dev_hold(rth->u.dst.dev);
1695 rth->idev = in_dev_get(rth->u.dst.dev);
1696 rth->fl.oif = 0;
1697 rth->rt_gateway = daddr;
1698 rth->rt_spec_dst= spec_dst;
1699 rth->rt_genid = atomic_read(&rt_genid);
1700 rth->rt_flags = RTCF_MULTICAST;
1701 rth->rt_type = RTN_MULTICAST;
1702 if (our) {
1703 rth->u.dst.input= ip_local_deliver;
1704 rth->rt_flags |= RTCF_LOCAL;
1705 }
1706
1707 #ifdef CONFIG_IP_MROUTE
1708 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1709 rth->u.dst.input = ip_mr_input;
1710 #endif
1711 RT_CACHE_STAT_INC(in_slow_mc);
1712
1713 in_dev_put(in_dev);
1714 hash = rt_hash(daddr, saddr, dev->ifindex);
1715 return rt_intern_hash(hash, rth, &skb->rtable);
1716
1717 e_nobufs:
1718 in_dev_put(in_dev);
1719 return -ENOBUFS;
1720
1721 e_inval:
1722 in_dev_put(in_dev);
1723 return -EINVAL;
1724 }
1725
1726
1727 static void ip_handle_martian_source(struct net_device *dev,
1728 struct in_device *in_dev,
1729 struct sk_buff *skb,
1730 __be32 daddr,
1731 __be32 saddr)
1732 {
1733 RT_CACHE_STAT_INC(in_martian_src);
1734 #ifdef CONFIG_IP_ROUTE_VERBOSE
1735 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1736 /*
1737 * RFC1812 recommendation, if source is martian,
1738 * the only hint is MAC header.
1739 */
1740 printk(KERN_WARNING "martian source " NIPQUAD_FMT " from "
1741 NIPQUAD_FMT", on dev %s\n",
1742 NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
1743 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1744 int i;
1745 const unsigned char *p = skb_mac_header(skb);
1746 printk(KERN_WARNING "ll header: ");
1747 for (i = 0; i < dev->hard_header_len; i++, p++) {
1748 printk("%02x", *p);
1749 if (i < (dev->hard_header_len - 1))
1750 printk(":");
1751 }
1752 printk("\n");
1753 }
1754 }
1755 #endif
1756 }
1757
1758 static int __mkroute_input(struct sk_buff *skb,
1759 struct fib_result *res,
1760 struct in_device *in_dev,
1761 __be32 daddr, __be32 saddr, u32 tos,
1762 struct rtable **result)
1763 {
1764
1765 struct rtable *rth;
1766 int err;
1767 struct in_device *out_dev;
1768 unsigned flags = 0;
1769 __be32 spec_dst;
1770 u32 itag;
1771
1772 /* get a working reference to the output device */
1773 out_dev = in_dev_get(FIB_RES_DEV(*res));
1774 if (out_dev == NULL) {
1775 if (net_ratelimit())
1776 printk(KERN_CRIT "Bug in ip_route_input" \
1777 "_slow(). Please, report\n");
1778 return -EINVAL;
1779 }
1780
1781
1782 err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
1783 in_dev->dev, &spec_dst, &itag);
1784 if (err < 0) {
1785 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1786 saddr);
1787
1788 err = -EINVAL;
1789 goto cleanup;
1790 }
1791
1792 if (err)
1793 flags |= RTCF_DIRECTSRC;
1794
1795 if (out_dev == in_dev && err && !(flags & RTCF_MASQ) &&
1796 (IN_DEV_SHARED_MEDIA(out_dev) ||
1797 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1798 flags |= RTCF_DOREDIRECT;
1799
1800 if (skb->protocol != htons(ETH_P_IP)) {
1801 /* Not IP (i.e. ARP). Do not create route, if it is
1802 * invalid for proxy arp. DNAT routes are always valid.
1803 */
1804 if (out_dev == in_dev) {
1805 err = -EINVAL;
1806 goto cleanup;
1807 }
1808 }
1809
1810
1811 rth = dst_alloc(&ipv4_dst_ops);
1812 if (!rth) {
1813 err = -ENOBUFS;
1814 goto cleanup;
1815 }
1816
1817 atomic_set(&rth->u.dst.__refcnt, 1);
1818 rth->u.dst.flags= DST_HOST;
1819 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
1820 rth->u.dst.flags |= DST_NOPOLICY;
1821 if (IN_DEV_CONF_GET(out_dev, NOXFRM))
1822 rth->u.dst.flags |= DST_NOXFRM;
1823 rth->fl.fl4_dst = daddr;
1824 rth->rt_dst = daddr;
1825 rth->fl.fl4_tos = tos;
1826 rth->fl.mark = skb->mark;
1827 rth->fl.fl4_src = saddr;
1828 rth->rt_src = saddr;
1829 rth->rt_gateway = daddr;
1830 rth->rt_iif =
1831 rth->fl.iif = in_dev->dev->ifindex;
1832 rth->u.dst.dev = (out_dev)->dev;
1833 dev_hold(rth->u.dst.dev);
1834 rth->idev = in_dev_get(rth->u.dst.dev);
1835 rth->fl.oif = 0;
1836 rth->rt_spec_dst= spec_dst;
1837
1838 rth->u.dst.input = ip_forward;
1839 rth->u.dst.output = ip_output;
1840 rth->rt_genid = atomic_read(&rt_genid);
1841
1842 rt_set_nexthop(rth, res, itag);
1843
1844 rth->rt_flags = flags;
1845
1846 *result = rth;
1847 err = 0;
1848 cleanup:
1849 /* release the working reference to the output device */
1850 in_dev_put(out_dev);
1851 return err;
1852 }
1853
1854 static int ip_mkroute_input(struct sk_buff *skb,
1855 struct fib_result *res,
1856 const struct flowi *fl,
1857 struct in_device *in_dev,
1858 __be32 daddr, __be32 saddr, u32 tos)
1859 {
1860 struct rtable* rth = NULL;
1861 int err;
1862 unsigned hash;
1863
1864 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1865 if (res->fi && res->fi->fib_nhs > 1 && fl->oif == 0)
1866 fib_select_multipath(fl, res);
1867 #endif
1868
1869 /* create a routing cache entry */
1870 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1871 if (err)
1872 return err;
1873
1874 /* put it into the cache */
1875 hash = rt_hash(daddr, saddr, fl->iif);
1876 return rt_intern_hash(hash, rth, &skb->rtable);
1877 }
1878
1879 /*
1880 * NOTE. We drop all the packets that has local source
1881 * addresses, because every properly looped back packet
1882 * must have correct destination already attached by output routine.
1883 *
1884 * Such approach solves two big problems:
1885 * 1. Not simplex devices are handled properly.
1886 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1887 */
1888
1889 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1890 u8 tos, struct net_device *dev)
1891 {
1892 struct fib_result res;
1893 struct in_device *in_dev = in_dev_get(dev);
1894 struct flowi fl = { .nl_u = { .ip4_u =
1895 { .daddr = daddr,
1896 .saddr = saddr,
1897 .tos = tos,
1898 .scope = RT_SCOPE_UNIVERSE,
1899 } },
1900 .mark = skb->mark,
1901 .iif = dev->ifindex };
1902 unsigned flags = 0;
1903 u32 itag = 0;
1904 struct rtable * rth;
1905 unsigned hash;
1906 __be32 spec_dst;
1907 int err = -EINVAL;
1908 int free_res = 0;
1909 struct net * net = dev_net(dev);
1910
1911 /* IP on this device is disabled. */
1912
1913 if (!in_dev)
1914 goto out;
1915
1916 /* Check for the most weird martians, which can be not detected
1917 by fib_lookup.
1918 */
1919
1920 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1921 ipv4_is_loopback(saddr))
1922 goto martian_source;
1923
1924 if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
1925 goto brd_input;
1926
1927 /* Accept zero addresses only to limited broadcast;
1928 * I even do not know to fix it or not. Waiting for complains :-)
1929 */
1930 if (ipv4_is_zeronet(saddr))
1931 goto martian_source;
1932
1933 if (ipv4_is_lbcast(daddr) || ipv4_is_zeronet(daddr) ||
1934 ipv4_is_loopback(daddr))
1935 goto martian_destination;
1936
1937 /*
1938 * Now we are ready to route packet.
1939 */
1940 if ((err = fib_lookup(net, &fl, &res)) != 0) {
1941 if (!IN_DEV_FORWARD(in_dev))
1942 goto e_hostunreach;
1943 goto no_route;
1944 }
1945 free_res = 1;
1946
1947 RT_CACHE_STAT_INC(in_slow_tot);
1948
1949 if (res.type == RTN_BROADCAST)
1950 goto brd_input;
1951
1952 if (res.type == RTN_LOCAL) {
1953 int result;
1954 result = fib_validate_source(saddr, daddr, tos,
1955 net->loopback_dev->ifindex,
1956 dev, &spec_dst, &itag);
1957 if (result < 0)
1958 goto martian_source;
1959 if (result)
1960 flags |= RTCF_DIRECTSRC;
1961 spec_dst = daddr;
1962 goto local_input;
1963 }
1964
1965 if (!IN_DEV_FORWARD(in_dev))
1966 goto e_hostunreach;
1967 if (res.type != RTN_UNICAST)
1968 goto martian_destination;
1969
1970 err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
1971 done:
1972 in_dev_put(in_dev);
1973 if (free_res)
1974 fib_res_put(&res);
1975 out: return err;
1976
1977 brd_input:
1978 if (skb->protocol != htons(ETH_P_IP))
1979 goto e_inval;
1980
1981 if (ipv4_is_zeronet(saddr))
1982 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1983 else {
1984 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
1985 &itag);
1986 if (err < 0)
1987 goto martian_source;
1988 if (err)
1989 flags |= RTCF_DIRECTSRC;
1990 }
1991 flags |= RTCF_BROADCAST;
1992 res.type = RTN_BROADCAST;
1993 RT_CACHE_STAT_INC(in_brd);
1994
1995 local_input:
1996 rth = dst_alloc(&ipv4_dst_ops);
1997 if (!rth)
1998 goto e_nobufs;
1999
2000 rth->u.dst.output= ip_rt_bug;
2001 rth->rt_genid = atomic_read(&rt_genid);
2002
2003 atomic_set(&rth->u.dst.__refcnt, 1);
2004 rth->u.dst.flags= DST_HOST;
2005 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
2006 rth->u.dst.flags |= DST_NOPOLICY;
2007 rth->fl.fl4_dst = daddr;
2008 rth->rt_dst = daddr;
2009 rth->fl.fl4_tos = tos;
2010 rth->fl.mark = skb->mark;
2011 rth->fl.fl4_src = saddr;
2012 rth->rt_src = saddr;
2013 #ifdef CONFIG_NET_CLS_ROUTE
2014 rth->u.dst.tclassid = itag;
2015 #endif
2016 rth->rt_iif =
2017 rth->fl.iif = dev->ifindex;
2018 rth->u.dst.dev = net->loopback_dev;
2019 dev_hold(rth->u.dst.dev);
2020 rth->idev = in_dev_get(rth->u.dst.dev);
2021 rth->rt_gateway = daddr;
2022 rth->rt_spec_dst= spec_dst;
2023 rth->u.dst.input= ip_local_deliver;
2024 rth->rt_flags = flags|RTCF_LOCAL;
2025 if (res.type == RTN_UNREACHABLE) {
2026 rth->u.dst.input= ip_error;
2027 rth->u.dst.error= -err;
2028 rth->rt_flags &= ~RTCF_LOCAL;
2029 }
2030 rth->rt_type = res.type;
2031 hash = rt_hash(daddr, saddr, fl.iif);
2032 err = rt_intern_hash(hash, rth, &skb->rtable);
2033 goto done;
2034
2035 no_route:
2036 RT_CACHE_STAT_INC(in_no_route);
2037 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2038 res.type = RTN_UNREACHABLE;
2039 if (err == -ESRCH)
2040 err = -ENETUNREACH;
2041 goto local_input;
2042
2043 /*
2044 * Do not cache martian addresses: they should be logged (RFC1812)
2045 */
2046 martian_destination:
2047 RT_CACHE_STAT_INC(in_martian_dst);
2048 #ifdef CONFIG_IP_ROUTE_VERBOSE
2049 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
2050 printk(KERN_WARNING "martian destination " NIPQUAD_FMT " from "
2051 NIPQUAD_FMT ", dev %s\n",
2052 NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
2053 #endif
2054
2055 e_hostunreach:
2056 err = -EHOSTUNREACH;
2057 goto done;
2058
2059 e_inval:
2060 err = -EINVAL;
2061 goto done;
2062
2063 e_nobufs:
2064 err = -ENOBUFS;
2065 goto done;
2066
2067 martian_source:
2068 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2069 goto e_inval;
2070 }
2071
2072 int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2073 u8 tos, struct net_device *dev)
2074 {
2075 struct rtable * rth;
2076 unsigned hash;
2077 int iif = dev->ifindex;
2078 struct net *net;
2079
2080 net = dev_net(dev);
2081 tos &= IPTOS_RT_MASK;
2082 hash = rt_hash(daddr, saddr, iif);
2083
2084 rcu_read_lock();
2085 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2086 rth = rcu_dereference(rth->u.dst.rt_next)) {
2087 if (((rth->fl.fl4_dst ^ daddr) |
2088 (rth->fl.fl4_src ^ saddr) |
2089 (rth->fl.iif ^ iif) |
2090 rth->fl.oif |
2091 (rth->fl.fl4_tos ^ tos)) == 0 &&
2092 rth->fl.mark == skb->mark &&
2093 net_eq(dev_net(rth->u.dst.dev), net) &&
2094 rth->rt_genid == atomic_read(&rt_genid)) {
2095 dst_use(&rth->u.dst, jiffies);
2096 RT_CACHE_STAT_INC(in_hit);
2097 rcu_read_unlock();
2098 skb->rtable = rth;
2099 return 0;
2100 }
2101 RT_CACHE_STAT_INC(in_hlist_search);
2102 }
2103 rcu_read_unlock();
2104
2105 /* Multicast recognition logic is moved from route cache to here.
2106 The problem was that too many Ethernet cards have broken/missing
2107 hardware multicast filters :-( As result the host on multicasting
2108 network acquires a lot of useless route cache entries, sort of
2109 SDR messages from all the world. Now we try to get rid of them.
2110 Really, provided software IP multicast filter is organized
2111 reasonably (at least, hashed), it does not result in a slowdown
2112 comparing with route cache reject entries.
2113 Note, that multicast routers are not affected, because
2114 route cache entry is created eventually.
2115 */
2116 if (ipv4_is_multicast(daddr)) {
2117 struct in_device *in_dev;
2118
2119 rcu_read_lock();
2120 if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
2121 int our = ip_check_mc(in_dev, daddr, saddr,
2122 ip_hdr(skb)->protocol);
2123 if (our
2124 #ifdef CONFIG_IP_MROUTE
2125 || (!ipv4_is_local_multicast(daddr) &&
2126 IN_DEV_MFORWARD(in_dev))
2127 #endif
2128 ) {
2129 rcu_read_unlock();
2130 return ip_route_input_mc(skb, daddr, saddr,
2131 tos, dev, our);
2132 }
2133 }
2134 rcu_read_unlock();
2135 return -EINVAL;
2136 }
2137 return ip_route_input_slow(skb, daddr, saddr, tos, dev);
2138 }
2139
2140 static int __mkroute_output(struct rtable **result,
2141 struct fib_result *res,
2142 const struct flowi *fl,
2143 const struct flowi *oldflp,
2144 struct net_device *dev_out,
2145 unsigned flags)
2146 {
2147 struct rtable *rth;
2148 struct in_device *in_dev;
2149 u32 tos = RT_FL_TOS(oldflp);
2150 int err = 0;
2151
2152 if (ipv4_is_loopback(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
2153 return -EINVAL;
2154
2155 if (fl->fl4_dst == htonl(0xFFFFFFFF))
2156 res->type = RTN_BROADCAST;
2157 else if (ipv4_is_multicast(fl->fl4_dst))
2158 res->type = RTN_MULTICAST;
2159 else if (ipv4_is_lbcast(fl->fl4_dst) || ipv4_is_zeronet(fl->fl4_dst))
2160 return -EINVAL;
2161
2162 if (dev_out->flags & IFF_LOOPBACK)
2163 flags |= RTCF_LOCAL;
2164
2165 /* get work reference to inet device */
2166 in_dev = in_dev_get(dev_out);
2167 if (!in_dev)
2168 return -EINVAL;
2169
2170 if (res->type == RTN_BROADCAST) {
2171 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2172 if (res->fi) {
2173 fib_info_put(res->fi);
2174 res->fi = NULL;
2175 }
2176 } else if (res->type == RTN_MULTICAST) {
2177 flags |= RTCF_MULTICAST|RTCF_LOCAL;
2178 if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
2179 oldflp->proto))
2180 flags &= ~RTCF_LOCAL;
2181 /* If multicast route do not exist use
2182 default one, but do not gateway in this case.
2183 Yes, it is hack.
2184 */
2185 if (res->fi && res->prefixlen < 4) {
2186 fib_info_put(res->fi);
2187 res->fi = NULL;
2188 }
2189 }
2190
2191
2192 rth = dst_alloc(&ipv4_dst_ops);
2193 if (!rth) {
2194 err = -ENOBUFS;
2195 goto cleanup;
2196 }
2197
2198 atomic_set(&rth->u.dst.__refcnt, 1);
2199 rth->u.dst.flags= DST_HOST;
2200 if (IN_DEV_CONF_GET(in_dev, NOXFRM))
2201 rth->u.dst.flags |= DST_NOXFRM;
2202 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
2203 rth->u.dst.flags |= DST_NOPOLICY;
2204
2205 rth->fl.fl4_dst = oldflp->fl4_dst;
2206 rth->fl.fl4_tos = tos;
2207 rth->fl.fl4_src = oldflp->fl4_src;
2208 rth->fl.oif = oldflp->oif;
2209 rth->fl.mark = oldflp->mark;
2210 rth->rt_dst = fl->fl4_dst;
2211 rth->rt_src = fl->fl4_src;
2212 rth->rt_iif = oldflp->oif ? : dev_out->ifindex;
2213 /* get references to the devices that are to be hold by the routing
2214 cache entry */
2215 rth->u.dst.dev = dev_out;
2216 dev_hold(dev_out);
2217 rth->idev = in_dev_get(dev_out);
2218 rth->rt_gateway = fl->fl4_dst;
2219 rth->rt_spec_dst= fl->fl4_src;
2220
2221 rth->u.dst.output=ip_output;
2222 rth->rt_genid = atomic_read(&rt_genid);
2223
2224 RT_CACHE_STAT_INC(out_slow_tot);
2225
2226 if (flags & RTCF_LOCAL) {
2227 rth->u.dst.input = ip_local_deliver;
2228 rth->rt_spec_dst = fl->fl4_dst;
2229 }
2230 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2231 rth->rt_spec_dst = fl->fl4_src;
2232 if (flags & RTCF_LOCAL &&
2233 !(dev_out->flags & IFF_LOOPBACK)) {
2234 rth->u.dst.output = ip_mc_output;
2235 RT_CACHE_STAT_INC(out_slow_mc);
2236 }
2237 #ifdef CONFIG_IP_MROUTE
2238 if (res->type == RTN_MULTICAST) {
2239 if (IN_DEV_MFORWARD(in_dev) &&
2240 !ipv4_is_local_multicast(oldflp->fl4_dst)) {
2241 rth->u.dst.input = ip_mr_input;
2242 rth->u.dst.output = ip_mc_output;
2243 }
2244 }
2245 #endif
2246 }
2247
2248 rt_set_nexthop(rth, res, 0);
2249
2250 rth->rt_flags = flags;
2251
2252 *result = rth;
2253 cleanup:
2254 /* release work reference to inet device */
2255 in_dev_put(in_dev);
2256
2257 return err;
2258 }
2259
2260 static int ip_mkroute_output(struct rtable **rp,
2261 struct fib_result *res,
2262 const struct flowi *fl,
2263 const struct flowi *oldflp,
2264 struct net_device *dev_out,
2265 unsigned flags)
2266 {
2267 struct rtable *rth = NULL;
2268 int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
2269 unsigned hash;
2270 if (err == 0) {
2271 hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif);
2272 err = rt_intern_hash(hash, rth, rp);
2273 }
2274
2275 return err;
2276 }
2277
2278 /*
2279 * Major route resolver routine.
2280 */
2281
2282 static int ip_route_output_slow(struct net *net, struct rtable **rp,
2283 const struct flowi *oldflp)
2284 {
2285 u32 tos = RT_FL_TOS(oldflp);
2286 struct flowi fl = { .nl_u = { .ip4_u =
2287 { .daddr = oldflp->fl4_dst,
2288 .saddr = oldflp->fl4_src,
2289 .tos = tos & IPTOS_RT_MASK,
2290 .scope = ((tos & RTO_ONLINK) ?
2291 RT_SCOPE_LINK :
2292 RT_SCOPE_UNIVERSE),
2293 } },
2294 .mark = oldflp->mark,
2295 .iif = net->loopback_dev->ifindex,
2296 .oif = oldflp->oif };
2297 struct fib_result res;
2298 unsigned flags = 0;
2299 struct net_device *dev_out = NULL;
2300 int free_res = 0;
2301 int err;
2302
2303
2304 res.fi = NULL;
2305 #ifdef CONFIG_IP_MULTIPLE_TABLES
2306 res.r = NULL;
2307 #endif
2308
2309 if (oldflp->fl4_src) {
2310 err = -EINVAL;
2311 if (ipv4_is_multicast(oldflp->fl4_src) ||
2312 ipv4_is_lbcast(oldflp->fl4_src) ||
2313 ipv4_is_zeronet(oldflp->fl4_src))
2314 goto out;
2315
2316 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2317 dev_out = ip_dev_find(net, oldflp->fl4_src);
2318 if (dev_out == NULL)
2319 goto out;
2320
2321 /* I removed check for oif == dev_out->oif here.
2322 It was wrong for two reasons:
2323 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2324 is assigned to multiple interfaces.
2325 2. Moreover, we are allowed to send packets with saddr
2326 of another iface. --ANK
2327 */
2328
2329 if (oldflp->oif == 0
2330 && (ipv4_is_multicast(oldflp->fl4_dst) ||
2331 oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
2332 /* Special hack: user can direct multicasts
2333 and limited broadcast via necessary interface
2334 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2335 This hack is not just for fun, it allows
2336 vic,vat and friends to work.
2337 They bind socket to loopback, set ttl to zero
2338 and expect that it will work.
2339 From the viewpoint of routing cache they are broken,
2340 because we are not allowed to build multicast path
2341 with loopback source addr (look, routing cache
2342 cannot know, that ttl is zero, so that packet
2343 will not leave this host and route is valid).
2344 Luckily, this hack is good workaround.
2345 */
2346
2347 fl.oif = dev_out->ifindex;
2348 goto make_route;
2349 }
2350 if (dev_out)
2351 dev_put(dev_out);
2352 dev_out = NULL;
2353 }
2354
2355
2356 if (oldflp->oif) {
2357 dev_out = dev_get_by_index(net, oldflp->oif);
2358 err = -ENODEV;
2359 if (dev_out == NULL)
2360 goto out;
2361
2362 /* RACE: Check return value of inet_select_addr instead. */
2363 if (__in_dev_get_rtnl(dev_out) == NULL) {
2364 dev_put(dev_out);
2365 goto out; /* Wrong error code */
2366 }
2367
2368 if (ipv4_is_local_multicast(oldflp->fl4_dst) ||
2369 oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
2370 if (!fl.fl4_src)
2371 fl.fl4_src = inet_select_addr(dev_out, 0,
2372 RT_SCOPE_LINK);
2373 goto make_route;
2374 }
2375 if (!fl.fl4_src) {
2376 if (ipv4_is_multicast(oldflp->fl4_dst))
2377 fl.fl4_src = inet_select_addr(dev_out, 0,
2378 fl.fl4_scope);
2379 else if (!oldflp->fl4_dst)
2380 fl.fl4_src = inet_select_addr(dev_out, 0,
2381 RT_SCOPE_HOST);
2382 }
2383 }
2384
2385 if (!fl.fl4_dst) {
2386 fl.fl4_dst = fl.fl4_src;
2387 if (!fl.fl4_dst)
2388 fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
2389 if (dev_out)
2390 dev_put(dev_out);
2391 dev_out = net->loopback_dev;
2392 dev_hold(dev_out);
2393 fl.oif = net->loopback_dev->ifindex;
2394 res.type = RTN_LOCAL;
2395 flags |= RTCF_LOCAL;
2396 goto make_route;
2397 }
2398
2399 if (fib_lookup(net, &fl, &res)) {
2400 res.fi = NULL;
2401 if (oldflp->oif) {
2402 /* Apparently, routing tables are wrong. Assume,
2403 that the destination is on link.
2404
2405 WHY? DW.
2406 Because we are allowed to send to iface
2407 even if it has NO routes and NO assigned
2408 addresses. When oif is specified, routing
2409 tables are looked up with only one purpose:
2410 to catch if destination is gatewayed, rather than
2411 direct. Moreover, if MSG_DONTROUTE is set,
2412 we send packet, ignoring both routing tables
2413 and ifaddr state. --ANK
2414
2415
2416 We could make it even if oif is unknown,
2417 likely IPv6, but we do not.
2418 */
2419
2420 if (fl.fl4_src == 0)
2421 fl.fl4_src = inet_select_addr(dev_out, 0,
2422 RT_SCOPE_LINK);
2423 res.type = RTN_UNICAST;
2424 goto make_route;
2425 }
2426 if (dev_out)
2427 dev_put(dev_out);
2428 err = -ENETUNREACH;
2429 goto out;
2430 }
2431 free_res = 1;
2432
2433 if (res.type == RTN_LOCAL) {
2434 if (!fl.fl4_src)
2435 fl.fl4_src = fl.fl4_dst;
2436 if (dev_out)
2437 dev_put(dev_out);
2438 dev_out = net->loopback_dev;
2439 dev_hold(dev_out);
2440 fl.oif = dev_out->ifindex;
2441 if (res.fi)
2442 fib_info_put(res.fi);
2443 res.fi = NULL;
2444 flags |= RTCF_LOCAL;
2445 goto make_route;
2446 }
2447
2448 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2449 if (res.fi->fib_nhs > 1 && fl.oif == 0)
2450 fib_select_multipath(&fl, &res);
2451 else
2452 #endif
2453 if (!res.prefixlen && res.type == RTN_UNICAST && !fl.oif)
2454 fib_select_default(net, &fl, &res);
2455
2456 if (!fl.fl4_src)
2457 fl.fl4_src = FIB_RES_PREFSRC(res);
2458
2459 if (dev_out)
2460 dev_put(dev_out);
2461 dev_out = FIB_RES_DEV(res);
2462 dev_hold(dev_out);
2463 fl.oif = dev_out->ifindex;
2464
2465
2466 make_route:
2467 err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
2468
2469
2470 if (free_res)
2471 fib_res_put(&res);
2472 if (dev_out)
2473 dev_put(dev_out);
2474 out: return err;
2475 }
2476
2477 int __ip_route_output_key(struct net *net, struct rtable **rp,
2478 const struct flowi *flp)
2479 {
2480 unsigned hash;
2481 struct rtable *rth;
2482
2483 hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif);
2484
2485 rcu_read_lock_bh();
2486 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2487 rth = rcu_dereference(rth->u.dst.rt_next)) {
2488 if (rth->fl.fl4_dst == flp->fl4_dst &&
2489 rth->fl.fl4_src == flp->fl4_src &&
2490 rth->fl.iif == 0 &&
2491 rth->fl.oif == flp->oif &&
2492 rth->fl.mark == flp->mark &&
2493 !((rth->fl.fl4_tos ^ flp->fl4_tos) &
2494 (IPTOS_RT_MASK | RTO_ONLINK)) &&
2495 net_eq(dev_net(rth->u.dst.dev), net) &&
2496 rth->rt_genid == atomic_read(&rt_genid)) {
2497 dst_use(&rth->u.dst, jiffies);
2498 RT_CACHE_STAT_INC(out_hit);
2499 rcu_read_unlock_bh();
2500 *rp = rth;
2501 return 0;
2502 }
2503 RT_CACHE_STAT_INC(out_hlist_search);
2504 }
2505 rcu_read_unlock_bh();
2506
2507 return ip_route_output_slow(net, rp, flp);
2508 }
2509
2510 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2511
2512 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2513 {
2514 }
2515
2516 static struct dst_ops ipv4_dst_blackhole_ops = {
2517 .family = AF_INET,
2518 .protocol = __constant_htons(ETH_P_IP),
2519 .destroy = ipv4_dst_destroy,
2520 .check = ipv4_dst_check,
2521 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2522 .entry_size = sizeof(struct rtable),
2523 .entries = ATOMIC_INIT(0),
2524 };
2525
2526
2527 static int ipv4_dst_blackhole(struct rtable **rp, struct flowi *flp)
2528 {
2529 struct rtable *ort = *rp;
2530 struct rtable *rt = (struct rtable *)
2531 dst_alloc(&ipv4_dst_blackhole_ops);
2532
2533 if (rt) {
2534 struct dst_entry *new = &rt->u.dst;
2535
2536 atomic_set(&new->__refcnt, 1);
2537 new->__use = 1;
2538 new->input = dst_discard;
2539 new->output = dst_discard;
2540 memcpy(new->metrics, ort->u.dst.metrics, RTAX_MAX*sizeof(u32));
2541
2542 new->dev = ort->u.dst.dev;
2543 if (new->dev)
2544 dev_hold(new->dev);
2545
2546 rt->fl = ort->fl;
2547
2548 rt->idev = ort->idev;
2549 if (rt->idev)
2550 in_dev_hold(rt->idev);
2551 rt->rt_genid = atomic_read(&rt_genid);
2552 rt->rt_flags = ort->rt_flags;
2553 rt->rt_type = ort->rt_type;
2554 rt->rt_dst = ort->rt_dst;
2555 rt->rt_src = ort->rt_src;
2556 rt->rt_iif = ort->rt_iif;
2557 rt->rt_gateway = ort->rt_gateway;
2558 rt->rt_spec_dst = ort->rt_spec_dst;
2559 rt->peer = ort->peer;
2560 if (rt->peer)
2561 atomic_inc(&rt->peer->refcnt);
2562
2563 dst_free(new);
2564 }
2565
2566 dst_release(&(*rp)->u.dst);
2567 *rp = rt;
2568 return (rt ? 0 : -ENOMEM);
2569 }
2570
2571 int ip_route_output_flow(struct net *net, struct rtable **rp, struct flowi *flp,
2572 struct sock *sk, int flags)
2573 {
2574 int err;
2575
2576 if ((err = __ip_route_output_key(net, rp, flp)) != 0)
2577 return err;
2578
2579 if (flp->proto) {
2580 if (!flp->fl4_src)
2581 flp->fl4_src = (*rp)->rt_src;
2582 if (!flp->fl4_dst)
2583 flp->fl4_dst = (*rp)->rt_dst;
2584 err = __xfrm_lookup((struct dst_entry **)rp, flp, sk,
2585 flags ? XFRM_LOOKUP_WAIT : 0);
2586 if (err == -EREMOTE)
2587 err = ipv4_dst_blackhole(rp, flp);
2588
2589 return err;
2590 }
2591
2592 return 0;
2593 }
2594
2595 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2596
2597 int ip_route_output_key(struct net *net, struct rtable **rp, struct flowi *flp)
2598 {
2599 return ip_route_output_flow(net, rp, flp, NULL, 0);
2600 }
2601
2602 static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
2603 int nowait, unsigned int flags)
2604 {
2605 struct rtable *rt = skb->rtable;
2606 struct rtmsg *r;
2607 struct nlmsghdr *nlh;
2608 long expires;
2609 u32 id = 0, ts = 0, tsage = 0, error;
2610
2611 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2612 if (nlh == NULL)
2613 return -EMSGSIZE;
2614
2615 r = nlmsg_data(nlh);
2616 r->rtm_family = AF_INET;
2617 r->rtm_dst_len = 32;
2618 r->rtm_src_len = 0;
2619 r->rtm_tos = rt->fl.fl4_tos;
2620 r->rtm_table = RT_TABLE_MAIN;
2621 NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
2622 r->rtm_type = rt->rt_type;
2623 r->rtm_scope = RT_SCOPE_UNIVERSE;
2624 r->rtm_protocol = RTPROT_UNSPEC;
2625 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2626 if (rt->rt_flags & RTCF_NOTIFY)
2627 r->rtm_flags |= RTM_F_NOTIFY;
2628
2629 NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2630
2631 if (rt->fl.fl4_src) {
2632 r->rtm_src_len = 32;
2633 NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src);
2634 }
2635 if (rt->u.dst.dev)
2636 NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex);
2637 #ifdef CONFIG_NET_CLS_ROUTE
2638 if (rt->u.dst.tclassid)
2639 NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid);
2640 #endif
2641 if (rt->fl.iif)
2642 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
2643 else if (rt->rt_src != rt->fl.fl4_src)
2644 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2645
2646 if (rt->rt_dst != rt->rt_gateway)
2647 NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2648
2649 if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2650 goto nla_put_failure;
2651
2652 error = rt->u.dst.error;
2653 expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
2654 if (rt->peer) {
2655 id = rt->peer->ip_id_count;
2656 if (rt->peer->tcp_ts_stamp) {
2657 ts = rt->peer->tcp_ts;
2658 tsage = get_seconds() - rt->peer->tcp_ts_stamp;
2659 }
2660 }
2661
2662 if (rt->fl.iif) {
2663 #ifdef CONFIG_IP_MROUTE
2664 __be32 dst = rt->rt_dst;
2665
2666 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2667 IPV4_DEVCONF_ALL(&init_net, MC_FORWARDING)) {
2668 int err = ipmr_get_route(skb, r, nowait);
2669 if (err <= 0) {
2670 if (!nowait) {
2671 if (err == 0)
2672 return 0;
2673 goto nla_put_failure;
2674 } else {
2675 if (err == -EMSGSIZE)
2676 goto nla_put_failure;
2677 error = err;
2678 }
2679 }
2680 } else
2681 #endif
2682 NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif);
2683 }
2684
2685 if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage,
2686 expires, error) < 0)
2687 goto nla_put_failure;
2688
2689 return nlmsg_end(skb, nlh);
2690
2691 nla_put_failure:
2692 nlmsg_cancel(skb, nlh);
2693 return -EMSGSIZE;
2694 }
2695
2696 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
2697 {
2698 struct net *net = sock_net(in_skb->sk);
2699 struct rtmsg *rtm;
2700 struct nlattr *tb[RTA_MAX+1];
2701 struct rtable *rt = NULL;
2702 __be32 dst = 0;
2703 __be32 src = 0;
2704 u32 iif;
2705 int err;
2706 struct sk_buff *skb;
2707
2708 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2709 if (err < 0)
2710 goto errout;
2711
2712 rtm = nlmsg_data(nlh);
2713
2714 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2715 if (skb == NULL) {
2716 err = -ENOBUFS;
2717 goto errout;
2718 }
2719
2720 /* Reserve room for dummy headers, this skb can pass
2721 through good chunk of routing engine.
2722 */
2723 skb_reset_mac_header(skb);
2724 skb_reset_network_header(skb);
2725
2726 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2727 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2728 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2729
2730 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2731 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2732 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2733
2734 if (iif) {
2735 struct net_device *dev;
2736
2737 dev = __dev_get_by_index(net, iif);
2738 if (dev == NULL) {
2739 err = -ENODEV;
2740 goto errout_free;
2741 }
2742
2743 skb->protocol = htons(ETH_P_IP);
2744 skb->dev = dev;
2745 local_bh_disable();
2746 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2747 local_bh_enable();
2748
2749 rt = skb->rtable;
2750 if (err == 0 && rt->u.dst.error)
2751 err = -rt->u.dst.error;
2752 } else {
2753 struct flowi fl = {
2754 .nl_u = {
2755 .ip4_u = {
2756 .daddr = dst,
2757 .saddr = src,
2758 .tos = rtm->rtm_tos,
2759 },
2760 },
2761 .oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
2762 };
2763 err = ip_route_output_key(net, &rt, &fl);
2764 }
2765
2766 if (err)
2767 goto errout_free;
2768
2769 skb->rtable = rt;
2770 if (rtm->rtm_flags & RTM_F_NOTIFY)
2771 rt->rt_flags |= RTCF_NOTIFY;
2772
2773 err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2774 RTM_NEWROUTE, 0, 0);
2775 if (err <= 0)
2776 goto errout_free;
2777
2778 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2779 errout:
2780 return err;
2781
2782 errout_free:
2783 kfree_skb(skb);
2784 goto errout;
2785 }
2786
2787 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
2788 {
2789 struct rtable *rt;
2790 int h, s_h;
2791 int idx, s_idx;
2792 struct net *net;
2793
2794 net = sock_net(skb->sk);
2795
2796 s_h = cb->args[0];
2797 if (s_h < 0)
2798 s_h = 0;
2799 s_idx = idx = cb->args[1];
2800 for (h = s_h; h <= rt_hash_mask; h++) {
2801 rcu_read_lock_bh();
2802 for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
2803 rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
2804 if (!net_eq(dev_net(rt->u.dst.dev), net) || idx < s_idx)
2805 continue;
2806 if (rt->rt_genid != atomic_read(&rt_genid))
2807 continue;
2808 skb->dst = dst_clone(&rt->u.dst);
2809 if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
2810 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2811 1, NLM_F_MULTI) <= 0) {
2812 dst_release(xchg(&skb->dst, NULL));
2813 rcu_read_unlock_bh();
2814 goto done;
2815 }
2816 dst_release(xchg(&skb->dst, NULL));
2817 }
2818 rcu_read_unlock_bh();
2819 s_idx = 0;
2820 }
2821
2822 done:
2823 cb->args[0] = h;
2824 cb->args[1] = idx;
2825 return skb->len;
2826 }
2827
2828 void ip_rt_multicast_event(struct in_device *in_dev)
2829 {
2830 rt_cache_flush(0);
2831 }
2832
2833 #ifdef CONFIG_SYSCTL
2834 static int flush_delay;
2835
2836 static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write,
2837 struct file *filp, void __user *buffer,
2838 size_t *lenp, loff_t *ppos)
2839 {
2840 if (write) {
2841 proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
2842 rt_cache_flush(flush_delay);
2843 return 0;
2844 }
2845
2846 return -EINVAL;
2847 }
2848
2849 static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table,
2850 int __user *name,
2851 int nlen,
2852 void __user *oldval,
2853 size_t __user *oldlenp,
2854 void __user *newval,
2855 size_t newlen)
2856 {
2857 int delay;
2858 if (newlen != sizeof(int))
2859 return -EINVAL;
2860 if (get_user(delay, (int __user *)newval))
2861 return -EFAULT;
2862 rt_cache_flush(delay);
2863 return 0;
2864 }
2865
2866 ctl_table ipv4_route_table[] = {
2867 {
2868 .ctl_name = NET_IPV4_ROUTE_FLUSH,
2869 .procname = "flush",
2870 .data = &flush_delay,
2871 .maxlen = sizeof(int),
2872 .mode = 0200,
2873 .proc_handler = &ipv4_sysctl_rtcache_flush,
2874 .strategy = &ipv4_sysctl_rtcache_flush_strategy,
2875 },
2876 {
2877 .ctl_name = NET_IPV4_ROUTE_GC_THRESH,
2878 .procname = "gc_thresh",
2879 .data = &ipv4_dst_ops.gc_thresh,
2880 .maxlen = sizeof(int),
2881 .mode = 0644,
2882 .proc_handler = &proc_dointvec,
2883 },
2884 {
2885 .ctl_name = NET_IPV4_ROUTE_MAX_SIZE,
2886 .procname = "max_size",
2887 .data = &ip_rt_max_size,
2888 .maxlen = sizeof(int),
2889 .mode = 0644,
2890 .proc_handler = &proc_dointvec,
2891 },
2892 {
2893 /* Deprecated. Use gc_min_interval_ms */
2894
2895 .ctl_name = NET_IPV4_ROUTE_GC_MIN_INTERVAL,
2896 .procname = "gc_min_interval",
2897 .data = &ip_rt_gc_min_interval,
2898 .maxlen = sizeof(int),
2899 .mode = 0644,
2900 .proc_handler = &proc_dointvec_jiffies,
2901 .strategy = &sysctl_jiffies,
2902 },
2903 {
2904 .ctl_name = NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS,
2905 .procname = "gc_min_interval_ms",
2906 .data = &ip_rt_gc_min_interval,
2907 .maxlen = sizeof(int),
2908 .mode = 0644,
2909 .proc_handler = &proc_dointvec_ms_jiffies,
2910 .strategy = &sysctl_ms_jiffies,
2911 },
2912 {
2913 .ctl_name = NET_IPV4_ROUTE_GC_TIMEOUT,
2914 .procname = "gc_timeout",
2915 .data = &ip_rt_gc_timeout,
2916 .maxlen = sizeof(int),
2917 .mode = 0644,
2918 .proc_handler = &proc_dointvec_jiffies,
2919 .strategy = &sysctl_jiffies,
2920 },
2921 {
2922 .ctl_name = NET_IPV4_ROUTE_GC_INTERVAL,
2923 .procname = "gc_interval",
2924 .data = &ip_rt_gc_interval,
2925 .maxlen = sizeof(int),
2926 .mode = 0644,
2927 .proc_handler = &proc_dointvec_jiffies,
2928 .strategy = &sysctl_jiffies,
2929 },
2930 {
2931 .ctl_name = NET_IPV4_ROUTE_REDIRECT_LOAD,
2932 .procname = "redirect_load",
2933 .data = &ip_rt_redirect_load,
2934 .maxlen = sizeof(int),
2935 .mode = 0644,
2936 .proc_handler = &proc_dointvec,
2937 },
2938 {
2939 .ctl_name = NET_IPV4_ROUTE_REDIRECT_NUMBER,
2940 .procname = "redirect_number",
2941 .data = &ip_rt_redirect_number,
2942 .maxlen = sizeof(int),
2943 .mode = 0644,
2944 .proc_handler = &proc_dointvec,
2945 },
2946 {
2947 .ctl_name = NET_IPV4_ROUTE_REDIRECT_SILENCE,
2948 .procname = "redirect_silence",
2949 .data = &ip_rt_redirect_silence,
2950 .maxlen = sizeof(int),
2951 .mode = 0644,
2952 .proc_handler = &proc_dointvec,
2953 },
2954 {
2955 .ctl_name = NET_IPV4_ROUTE_ERROR_COST,
2956 .procname = "error_cost",
2957 .data = &ip_rt_error_cost,
2958 .maxlen = sizeof(int),
2959 .mode = 0644,
2960 .proc_handler = &proc_dointvec,
2961 },
2962 {
2963 .ctl_name = NET_IPV4_ROUTE_ERROR_BURST,
2964 .procname = "error_burst",
2965 .data = &ip_rt_error_burst,
2966 .maxlen = sizeof(int),
2967 .mode = 0644,
2968 .proc_handler = &proc_dointvec,
2969 },
2970 {
2971 .ctl_name = NET_IPV4_ROUTE_GC_ELASTICITY,
2972 .procname = "gc_elasticity",
2973 .data = &ip_rt_gc_elasticity,
2974 .maxlen = sizeof(int),
2975 .mode = 0644,
2976 .proc_handler = &proc_dointvec,
2977 },
2978 {
2979 .ctl_name = NET_IPV4_ROUTE_MTU_EXPIRES,
2980 .procname = "mtu_expires",
2981 .data = &ip_rt_mtu_expires,
2982 .maxlen = sizeof(int),
2983 .mode = 0644,
2984 .proc_handler = &proc_dointvec_jiffies,
2985 .strategy = &sysctl_jiffies,
2986 },
2987 {
2988 .ctl_name = NET_IPV4_ROUTE_MIN_PMTU,
2989 .procname = "min_pmtu",
2990 .data = &ip_rt_min_pmtu,
2991 .maxlen = sizeof(int),
2992 .mode = 0644,
2993 .proc_handler = &proc_dointvec,
2994 },
2995 {
2996 .ctl_name = NET_IPV4_ROUTE_MIN_ADVMSS,
2997 .procname = "min_adv_mss",
2998 .data = &ip_rt_min_advmss,
2999 .maxlen = sizeof(int),
3000 .mode = 0644,
3001 .proc_handler = &proc_dointvec,
3002 },
3003 {
3004 .ctl_name = NET_IPV4_ROUTE_SECRET_INTERVAL,
3005 .procname = "secret_interval",
3006 .data = &ip_rt_secret_interval,
3007 .maxlen = sizeof(int),
3008 .mode = 0644,
3009 .proc_handler = &proc_dointvec_jiffies,
3010 .strategy = &sysctl_jiffies,
3011 },
3012 { .ctl_name = 0 }
3013 };
3014 #endif
3015
3016 #ifdef CONFIG_NET_CLS_ROUTE
3017 struct ip_rt_acct *ip_rt_acct __read_mostly;
3018 #endif /* CONFIG_NET_CLS_ROUTE */
3019
3020 static __initdata unsigned long rhash_entries;
3021 static int __init set_rhash_entries(char *str)
3022 {
3023 if (!str)
3024 return 0;
3025 rhash_entries = simple_strtoul(str, &str, 0);
3026 return 1;
3027 }
3028 __setup("rhash_entries=", set_rhash_entries);
3029
3030 int __init ip_rt_init(void)
3031 {
3032 int rc = 0;
3033
3034 atomic_set(&rt_genid, (int) ((num_physpages ^ (num_physpages>>8)) ^
3035 (jiffies ^ (jiffies >> 7))));
3036
3037 #ifdef CONFIG_NET_CLS_ROUTE
3038 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct));
3039 if (!ip_rt_acct)
3040 panic("IP: failed to allocate ip_rt_acct\n");
3041 #endif
3042
3043 ipv4_dst_ops.kmem_cachep =
3044 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3045 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3046
3047 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3048
3049 rt_hash_table = (struct rt_hash_bucket *)
3050 alloc_large_system_hash("IP route cache",
3051 sizeof(struct rt_hash_bucket),
3052 rhash_entries,
3053 (num_physpages >= 128 * 1024) ?
3054 15 : 17,
3055 0,
3056 &rt_hash_log,
3057 &rt_hash_mask,
3058 0);
3059 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3060 rt_hash_lock_init();
3061
3062 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3063 ip_rt_max_size = (rt_hash_mask + 1) * 16;
3064
3065 devinet_init();
3066 ip_fib_init();
3067
3068 rt_secret_timer.function = rt_secret_rebuild;
3069 rt_secret_timer.data = 0;
3070 init_timer_deferrable(&rt_secret_timer);
3071
3072 /* All the timers, started at system startup tend
3073 to synchronize. Perturb it a bit.
3074 */
3075 schedule_delayed_work(&expires_work,
3076 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3077
3078 rt_secret_timer.expires = jiffies + net_random() % ip_rt_secret_interval +
3079 ip_rt_secret_interval;
3080 add_timer(&rt_secret_timer);
3081
3082 if (ip_rt_proc_init())
3083 printk(KERN_ERR "Unable to create route proc files\n");
3084 #ifdef CONFIG_XFRM
3085 xfrm_init();
3086 xfrm4_init();
3087 #endif
3088 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);
3089
3090 return rc;
3091 }
3092
3093 EXPORT_SYMBOL(__ip_select_ident);
3094 EXPORT_SYMBOL(ip_route_input);
3095 EXPORT_SYMBOL(ip_route_output_key);
Linux 2.6 libata-dev (mirror)