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brcmsmac: get board and chip info from bcma
[linux-2.6/libata-dev.git] / net / ipv4 / route.c
blob5773f5d9e213e4319075a4dfb2bb3e22728b20f1
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * ROUTE - implementation of the IP router.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
13 *
14 * Fixes:
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
24 * clamper.
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
39 *
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
58 *
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
63 */
64
65 #define pr_fmt(fmt) "IPv4: " fmt
66
67 #include <linux/module.h>
68 #include <asm/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/types.h>
71 #include <linux/kernel.h>
72 #include <linux/mm.h>
73 #include <linux/bootmem.h>
74 #include <linux/string.h>
75 #include <linux/socket.h>
76 #include <linux/sockios.h>
77 #include <linux/errno.h>
78 #include <linux/in.h>
79 #include <linux/inet.h>
80 #include <linux/netdevice.h>
81 #include <linux/proc_fs.h>
82 #include <linux/init.h>
83 #include <linux/workqueue.h>
84 #include <linux/skbuff.h>
85 #include <linux/inetdevice.h>
86 #include <linux/igmp.h>
87 #include <linux/pkt_sched.h>
88 #include <linux/mroute.h>
89 #include <linux/netfilter_ipv4.h>
90 #include <linux/random.h>
91 #include <linux/jhash.h>
92 #include <linux/rcupdate.h>
93 #include <linux/times.h>
94 #include <linux/slab.h>
95 #include <linux/prefetch.h>
96 #include <net/dst.h>
97 #include <net/net_namespace.h>
98 #include <net/protocol.h>
99 #include <net/ip.h>
100 #include <net/route.h>
101 #include <net/inetpeer.h>
102 #include <net/sock.h>
103 #include <net/ip_fib.h>
104 #include <net/arp.h>
105 #include <net/tcp.h>
106 #include <net/icmp.h>
107 #include <net/xfrm.h>
108 #include <net/netevent.h>
109 #include <net/rtnetlink.h>
110 #ifdef CONFIG_SYSCTL
111 #include <linux/sysctl.h>
112 #include <linux/kmemleak.h>
113 #endif
114 #include <net/secure_seq.h>
115
116 #define RT_FL_TOS(oldflp4) \
117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
118
119 #define IP_MAX_MTU 0xFFF0
120
121 #define RT_GC_TIMEOUT (300*HZ)
122
123 static int ip_rt_max_size;
124 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
125 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
126 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
127 static int ip_rt_redirect_number __read_mostly = 9;
128 static int ip_rt_redirect_load __read_mostly = HZ / 50;
129 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
130 static int ip_rt_error_cost __read_mostly = HZ;
131 static int ip_rt_error_burst __read_mostly = 5 * HZ;
132 static int ip_rt_gc_elasticity __read_mostly = 8;
133 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
134 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
135 static int ip_rt_min_advmss __read_mostly = 256;
136 static int rt_chain_length_max __read_mostly = 20;
137
138 static struct delayed_work expires_work;
139 static unsigned long expires_ljiffies;
140
141 /*
142 * Interface to generic destination cache.
143 */
144
145 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
146 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
147 static unsigned int ipv4_mtu(const struct dst_entry *dst);
148 static void ipv4_dst_destroy(struct dst_entry *dst);
149 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
150 static void ipv4_link_failure(struct sk_buff *skb);
151 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
152 static int rt_garbage_collect(struct dst_ops *ops);
153
154 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
155 int how)
156 {
157 }
158
159 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
160 {
161 struct rtable *rt = (struct rtable *) dst;
162 struct inet_peer *peer;
163 u32 *p = NULL;
164
165 if (!rt->peer)
166 rt_bind_peer(rt, rt->rt_dst, 1);
167
168 peer = rt->peer;
169 if (peer) {
170 u32 *old_p = __DST_METRICS_PTR(old);
171 unsigned long prev, new;
172
173 p = peer->metrics;
174 if (inet_metrics_new(peer))
175 memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
176
177 new = (unsigned long) p;
178 prev = cmpxchg(&dst->_metrics, old, new);
179
180 if (prev != old) {
181 p = __DST_METRICS_PTR(prev);
182 if (prev & DST_METRICS_READ_ONLY)
183 p = NULL;
184 } else {
185 if (rt->fi) {
186 fib_info_put(rt->fi);
187 rt->fi = NULL;
188 }
189 }
190 }
191 return p;
192 }
193
194 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr);
195
196 static struct dst_ops ipv4_dst_ops = {
197 .family = AF_INET,
198 .protocol = cpu_to_be16(ETH_P_IP),
199 .gc = rt_garbage_collect,
200 .check = ipv4_dst_check,
201 .default_advmss = ipv4_default_advmss,
202 .mtu = ipv4_mtu,
203 .cow_metrics = ipv4_cow_metrics,
204 .destroy = ipv4_dst_destroy,
205 .ifdown = ipv4_dst_ifdown,
206 .negative_advice = ipv4_negative_advice,
207 .link_failure = ipv4_link_failure,
208 .update_pmtu = ip_rt_update_pmtu,
209 .local_out = __ip_local_out,
210 .neigh_lookup = ipv4_neigh_lookup,
211 };
212
213 #define ECN_OR_COST(class) TC_PRIO_##class
214
215 const __u8 ip_tos2prio[16] = {
216 TC_PRIO_BESTEFFORT,
217 ECN_OR_COST(BESTEFFORT),
218 TC_PRIO_BESTEFFORT,
219 ECN_OR_COST(BESTEFFORT),
220 TC_PRIO_BULK,
221 ECN_OR_COST(BULK),
222 TC_PRIO_BULK,
223 ECN_OR_COST(BULK),
224 TC_PRIO_INTERACTIVE,
225 ECN_OR_COST(INTERACTIVE),
226 TC_PRIO_INTERACTIVE,
227 ECN_OR_COST(INTERACTIVE),
228 TC_PRIO_INTERACTIVE_BULK,
229 ECN_OR_COST(INTERACTIVE_BULK),
230 TC_PRIO_INTERACTIVE_BULK,
231 ECN_OR_COST(INTERACTIVE_BULK)
232 };
233 EXPORT_SYMBOL(ip_tos2prio);
234
235 /*
236 * Route cache.
237 */
238
239 /* The locking scheme is rather straight forward:
240 *
241 * 1) Read-Copy Update protects the buckets of the central route hash.
242 * 2) Only writers remove entries, and they hold the lock
243 * as they look at rtable reference counts.
244 * 3) Only readers acquire references to rtable entries,
245 * they do so with atomic increments and with the
246 * lock held.
247 */
248
249 struct rt_hash_bucket {
250 struct rtable __rcu *chain;
251 };
252
253 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
254 defined(CONFIG_PROVE_LOCKING)
255 /*
256 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
257 * The size of this table is a power of two and depends on the number of CPUS.
258 * (on lockdep we have a quite big spinlock_t, so keep the size down there)
259 */
260 #ifdef CONFIG_LOCKDEP
261 # define RT_HASH_LOCK_SZ 256
262 #else
263 # if NR_CPUS >= 32
264 # define RT_HASH_LOCK_SZ 4096
265 # elif NR_CPUS >= 16
266 # define RT_HASH_LOCK_SZ 2048
267 # elif NR_CPUS >= 8
268 # define RT_HASH_LOCK_SZ 1024
269 # elif NR_CPUS >= 4
270 # define RT_HASH_LOCK_SZ 512
271 # else
272 # define RT_HASH_LOCK_SZ 256
273 # endif
274 #endif
275
276 static spinlock_t *rt_hash_locks;
277 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
278
279 static __init void rt_hash_lock_init(void)
280 {
281 int i;
282
283 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
284 GFP_KERNEL);
285 if (!rt_hash_locks)
286 panic("IP: failed to allocate rt_hash_locks\n");
287
288 for (i = 0; i < RT_HASH_LOCK_SZ; i++)
289 spin_lock_init(&rt_hash_locks[i]);
290 }
291 #else
292 # define rt_hash_lock_addr(slot) NULL
293
294 static inline void rt_hash_lock_init(void)
295 {
296 }
297 #endif
298
299 static struct rt_hash_bucket *rt_hash_table __read_mostly;
300 static unsigned int rt_hash_mask __read_mostly;
301 static unsigned int rt_hash_log __read_mostly;
302
303 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
304 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
305
306 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
307 int genid)
308 {
309 return jhash_3words((__force u32)daddr, (__force u32)saddr,
310 idx, genid)
311 & rt_hash_mask;
312 }
313
314 static inline int rt_genid(struct net *net)
315 {
316 return atomic_read(&net->ipv4.rt_genid);
317 }
318
319 #ifdef CONFIG_PROC_FS
320 struct rt_cache_iter_state {
321 struct seq_net_private p;
322 int bucket;
323 int genid;
324 };
325
326 static struct rtable *rt_cache_get_first(struct seq_file *seq)
327 {
328 struct rt_cache_iter_state *st = seq->private;
329 struct rtable *r = NULL;
330
331 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
332 if (!rcu_access_pointer(rt_hash_table[st->bucket].chain))
333 continue;
334 rcu_read_lock_bh();
335 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
336 while (r) {
337 if (dev_net(r->dst.dev) == seq_file_net(seq) &&
338 r->rt_genid == st->genid)
339 return r;
340 r = rcu_dereference_bh(r->dst.rt_next);
341 }
342 rcu_read_unlock_bh();
343 }
344 return r;
345 }
346
347 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
348 struct rtable *r)
349 {
350 struct rt_cache_iter_state *st = seq->private;
351
352 r = rcu_dereference_bh(r->dst.rt_next);
353 while (!r) {
354 rcu_read_unlock_bh();
355 do {
356 if (--st->bucket < 0)
357 return NULL;
358 } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain));
359 rcu_read_lock_bh();
360 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
361 }
362 return r;
363 }
364
365 static struct rtable *rt_cache_get_next(struct seq_file *seq,
366 struct rtable *r)
367 {
368 struct rt_cache_iter_state *st = seq->private;
369 while ((r = __rt_cache_get_next(seq, r)) != NULL) {
370 if (dev_net(r->dst.dev) != seq_file_net(seq))
371 continue;
372 if (r->rt_genid == st->genid)
373 break;
374 }
375 return r;
376 }
377
378 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
379 {
380 struct rtable *r = rt_cache_get_first(seq);
381
382 if (r)
383 while (pos && (r = rt_cache_get_next(seq, r)))
384 --pos;
385 return pos ? NULL : r;
386 }
387
388 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
389 {
390 struct rt_cache_iter_state *st = seq->private;
391 if (*pos)
392 return rt_cache_get_idx(seq, *pos - 1);
393 st->genid = rt_genid(seq_file_net(seq));
394 return SEQ_START_TOKEN;
395 }
396
397 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
398 {
399 struct rtable *r;
400
401 if (v == SEQ_START_TOKEN)
402 r = rt_cache_get_first(seq);
403 else
404 r = rt_cache_get_next(seq, v);
405 ++*pos;
406 return r;
407 }
408
409 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
410 {
411 if (v && v != SEQ_START_TOKEN)
412 rcu_read_unlock_bh();
413 }
414
415 static int rt_cache_seq_show(struct seq_file *seq, void *v)
416 {
417 if (v == SEQ_START_TOKEN)
418 seq_printf(seq, "%-127s\n",
419 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
420 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
421 "HHUptod\tSpecDst");
422 else {
423 struct rtable *r = v;
424 struct neighbour *n;
425 int len, HHUptod;
426
427 rcu_read_lock();
428 n = dst_get_neighbour_noref(&r->dst);
429 HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0;
430 rcu_read_unlock();
431
432 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
433 "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
434 r->dst.dev ? r->dst.dev->name : "*",
435 (__force u32)r->rt_dst,
436 (__force u32)r->rt_gateway,
437 r->rt_flags, atomic_read(&r->dst.__refcnt),
438 r->dst.__use, 0, (__force u32)r->rt_src,
439 dst_metric_advmss(&r->dst) + 40,
440 dst_metric(&r->dst, RTAX_WINDOW),
441 (int)((dst_metric(&r->dst, RTAX_RTT) >> 3) +
442 dst_metric(&r->dst, RTAX_RTTVAR)),
443 r->rt_key_tos,
444 -1,
445 HHUptod,
446 r->rt_spec_dst, &len);
447
448 seq_printf(seq, "%*s\n", 127 - len, "");
449 }
450 return 0;
451 }
452
453 static const struct seq_operations rt_cache_seq_ops = {
454 .start = rt_cache_seq_start,
455 .next = rt_cache_seq_next,
456 .stop = rt_cache_seq_stop,
457 .show = rt_cache_seq_show,
458 };
459
460 static int rt_cache_seq_open(struct inode *inode, struct file *file)
461 {
462 return seq_open_net(inode, file, &rt_cache_seq_ops,
463 sizeof(struct rt_cache_iter_state));
464 }
465
466 static const struct file_operations rt_cache_seq_fops = {
467 .owner = THIS_MODULE,
468 .open = rt_cache_seq_open,
469 .read = seq_read,
470 .llseek = seq_lseek,
471 .release = seq_release_net,
472 };
473
474
475 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
476 {
477 int cpu;
478
479 if (*pos == 0)
480 return SEQ_START_TOKEN;
481
482 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
483 if (!cpu_possible(cpu))
484 continue;
485 *pos = cpu+1;
486 return &per_cpu(rt_cache_stat, cpu);
487 }
488 return NULL;
489 }
490
491 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
492 {
493 int cpu;
494
495 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
496 if (!cpu_possible(cpu))
497 continue;
498 *pos = cpu+1;
499 return &per_cpu(rt_cache_stat, cpu);
500 }
501 return NULL;
502
503 }
504
505 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
506 {
507
508 }
509
510 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
511 {
512 struct rt_cache_stat *st = v;
513
514 if (v == SEQ_START_TOKEN) {
515 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
516 return 0;
517 }
518
519 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
520 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
521 dst_entries_get_slow(&ipv4_dst_ops),
522 st->in_hit,
523 st->in_slow_tot,
524 st->in_slow_mc,
525 st->in_no_route,
526 st->in_brd,
527 st->in_martian_dst,
528 st->in_martian_src,
529
530 st->out_hit,
531 st->out_slow_tot,
532 st->out_slow_mc,
533
534 st->gc_total,
535 st->gc_ignored,
536 st->gc_goal_miss,
537 st->gc_dst_overflow,
538 st->in_hlist_search,
539 st->out_hlist_search
540 );
541 return 0;
542 }
543
544 static const struct seq_operations rt_cpu_seq_ops = {
545 .start = rt_cpu_seq_start,
546 .next = rt_cpu_seq_next,
547 .stop = rt_cpu_seq_stop,
548 .show = rt_cpu_seq_show,
549 };
550
551
552 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
553 {
554 return seq_open(file, &rt_cpu_seq_ops);
555 }
556
557 static const struct file_operations rt_cpu_seq_fops = {
558 .owner = THIS_MODULE,
559 .open = rt_cpu_seq_open,
560 .read = seq_read,
561 .llseek = seq_lseek,
562 .release = seq_release,
563 };
564
565 #ifdef CONFIG_IP_ROUTE_CLASSID
566 static int rt_acct_proc_show(struct seq_file *m, void *v)
567 {
568 struct ip_rt_acct *dst, *src;
569 unsigned int i, j;
570
571 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
572 if (!dst)
573 return -ENOMEM;
574
575 for_each_possible_cpu(i) {
576 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
577 for (j = 0; j < 256; j++) {
578 dst[j].o_bytes += src[j].o_bytes;
579 dst[j].o_packets += src[j].o_packets;
580 dst[j].i_bytes += src[j].i_bytes;
581 dst[j].i_packets += src[j].i_packets;
582 }
583 }
584
585 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
586 kfree(dst);
587 return 0;
588 }
589
590 static int rt_acct_proc_open(struct inode *inode, struct file *file)
591 {
592 return single_open(file, rt_acct_proc_show, NULL);
593 }
594
595 static const struct file_operations rt_acct_proc_fops = {
596 .owner = THIS_MODULE,
597 .open = rt_acct_proc_open,
598 .read = seq_read,
599 .llseek = seq_lseek,
600 .release = single_release,
601 };
602 #endif
603
604 static int __net_init ip_rt_do_proc_init(struct net *net)
605 {
606 struct proc_dir_entry *pde;
607
608 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
609 &rt_cache_seq_fops);
610 if (!pde)
611 goto err1;
612
613 pde = proc_create("rt_cache", S_IRUGO,
614 net->proc_net_stat, &rt_cpu_seq_fops);
615 if (!pde)
616 goto err2;
617
618 #ifdef CONFIG_IP_ROUTE_CLASSID
619 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
620 if (!pde)
621 goto err3;
622 #endif
623 return 0;
624
625 #ifdef CONFIG_IP_ROUTE_CLASSID
626 err3:
627 remove_proc_entry("rt_cache", net->proc_net_stat);
628 #endif
629 err2:
630 remove_proc_entry("rt_cache", net->proc_net);
631 err1:
632 return -ENOMEM;
633 }
634
635 static void __net_exit ip_rt_do_proc_exit(struct net *net)
636 {
637 remove_proc_entry("rt_cache", net->proc_net_stat);
638 remove_proc_entry("rt_cache", net->proc_net);
639 #ifdef CONFIG_IP_ROUTE_CLASSID
640 remove_proc_entry("rt_acct", net->proc_net);
641 #endif
642 }
643
644 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
645 .init = ip_rt_do_proc_init,
646 .exit = ip_rt_do_proc_exit,
647 };
648
649 static int __init ip_rt_proc_init(void)
650 {
651 return register_pernet_subsys(&ip_rt_proc_ops);
652 }
653
654 #else
655 static inline int ip_rt_proc_init(void)
656 {
657 return 0;
658 }
659 #endif /* CONFIG_PROC_FS */
660
661 static inline void rt_free(struct rtable *rt)
662 {
663 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
664 }
665
666 static inline void rt_drop(struct rtable *rt)
667 {
668 ip_rt_put(rt);
669 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
670 }
671
672 static inline int rt_fast_clean(struct rtable *rth)
673 {
674 /* Kill broadcast/multicast entries very aggresively, if they
675 collide in hash table with more useful entries */
676 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
677 rt_is_input_route(rth) && rth->dst.rt_next;
678 }
679
680 static inline int rt_valuable(struct rtable *rth)
681 {
682 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
683 (rth->peer && rth->peer->pmtu_expires);
684 }
685
686 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
687 {
688 unsigned long age;
689 int ret = 0;
690
691 if (atomic_read(&rth->dst.__refcnt))
692 goto out;
693
694 age = jiffies - rth->dst.lastuse;
695 if ((age <= tmo1 && !rt_fast_clean(rth)) ||
696 (age <= tmo2 && rt_valuable(rth)))
697 goto out;
698 ret = 1;
699 out: return ret;
700 }
701
702 /* Bits of score are:
703 * 31: very valuable
704 * 30: not quite useless
705 * 29..0: usage counter
706 */
707 static inline u32 rt_score(struct rtable *rt)
708 {
709 u32 score = jiffies - rt->dst.lastuse;
710
711 score = ~score & ~(3<<30);
712
713 if (rt_valuable(rt))
714 score |= (1<<31);
715
716 if (rt_is_output_route(rt) ||
717 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
718 score |= (1<<30);
719
720 return score;
721 }
722
723 static inline bool rt_caching(const struct net *net)
724 {
725 return net->ipv4.current_rt_cache_rebuild_count <=
726 net->ipv4.sysctl_rt_cache_rebuild_count;
727 }
728
729 static inline bool compare_hash_inputs(const struct rtable *rt1,
730 const struct rtable *rt2)
731 {
732 return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
733 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
734 (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0);
735 }
736
737 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2)
738 {
739 return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
740 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
741 (rt1->rt_mark ^ rt2->rt_mark) |
742 (rt1->rt_key_tos ^ rt2->rt_key_tos) |
743 (rt1->rt_route_iif ^ rt2->rt_route_iif) |
744 (rt1->rt_oif ^ rt2->rt_oif)) == 0;
745 }
746
747 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
748 {
749 return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev));
750 }
751
752 static inline int rt_is_expired(struct rtable *rth)
753 {
754 return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
755 }
756
757 /*
758 * Perform a full scan of hash table and free all entries.
759 * Can be called by a softirq or a process.
760 * In the later case, we want to be reschedule if necessary
761 */
762 static void rt_do_flush(struct net *net, int process_context)
763 {
764 unsigned int i;
765 struct rtable *rth, *next;
766
767 for (i = 0; i <= rt_hash_mask; i++) {
768 struct rtable __rcu **pprev;
769 struct rtable *list;
770
771 if (process_context && need_resched())
772 cond_resched();
773 rth = rcu_access_pointer(rt_hash_table[i].chain);
774 if (!rth)
775 continue;
776
777 spin_lock_bh(rt_hash_lock_addr(i));
778
779 list = NULL;
780 pprev = &rt_hash_table[i].chain;
781 rth = rcu_dereference_protected(*pprev,
782 lockdep_is_held(rt_hash_lock_addr(i)));
783
784 while (rth) {
785 next = rcu_dereference_protected(rth->dst.rt_next,
786 lockdep_is_held(rt_hash_lock_addr(i)));
787
788 if (!net ||
789 net_eq(dev_net(rth->dst.dev), net)) {
790 rcu_assign_pointer(*pprev, next);
791 rcu_assign_pointer(rth->dst.rt_next, list);
792 list = rth;
793 } else {
794 pprev = &rth->dst.rt_next;
795 }
796 rth = next;
797 }
798
799 spin_unlock_bh(rt_hash_lock_addr(i));
800
801 for (; list; list = next) {
802 next = rcu_dereference_protected(list->dst.rt_next, 1);
803 rt_free(list);
804 }
805 }
806 }
807
808 /*
809 * While freeing expired entries, we compute average chain length
810 * and standard deviation, using fixed-point arithmetic.
811 * This to have an estimation of rt_chain_length_max
812 * rt_chain_length_max = max(elasticity, AVG + 4*SD)
813 * We use 3 bits for frational part, and 29 (or 61) for magnitude.
814 */
815
816 #define FRACT_BITS 3
817 #define ONE (1UL << FRACT_BITS)
818
819 /*
820 * Given a hash chain and an item in this hash chain,
821 * find if a previous entry has the same hash_inputs
822 * (but differs on tos, mark or oif)
823 * Returns 0 if an alias is found.
824 * Returns ONE if rth has no alias before itself.
825 */
826 static int has_noalias(const struct rtable *head, const struct rtable *rth)
827 {
828 const struct rtable *aux = head;
829
830 while (aux != rth) {
831 if (compare_hash_inputs(aux, rth))
832 return 0;
833 aux = rcu_dereference_protected(aux->dst.rt_next, 1);
834 }
835 return ONE;
836 }
837
838 static void rt_check_expire(void)
839 {
840 static unsigned int rover;
841 unsigned int i = rover, goal;
842 struct rtable *rth;
843 struct rtable __rcu **rthp;
844 unsigned long samples = 0;
845 unsigned long sum = 0, sum2 = 0;
846 unsigned long delta;
847 u64 mult;
848
849 delta = jiffies - expires_ljiffies;
850 expires_ljiffies = jiffies;
851 mult = ((u64)delta) << rt_hash_log;
852 if (ip_rt_gc_timeout > 1)
853 do_div(mult, ip_rt_gc_timeout);
854 goal = (unsigned int)mult;
855 if (goal > rt_hash_mask)
856 goal = rt_hash_mask + 1;
857 for (; goal > 0; goal--) {
858 unsigned long tmo = ip_rt_gc_timeout;
859 unsigned long length;
860
861 i = (i + 1) & rt_hash_mask;
862 rthp = &rt_hash_table[i].chain;
863
864 if (need_resched())
865 cond_resched();
866
867 samples++;
868
869 if (rcu_dereference_raw(*rthp) == NULL)
870 continue;
871 length = 0;
872 spin_lock_bh(rt_hash_lock_addr(i));
873 while ((rth = rcu_dereference_protected(*rthp,
874 lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) {
875 prefetch(rth->dst.rt_next);
876 if (rt_is_expired(rth)) {
877 *rthp = rth->dst.rt_next;
878 rt_free(rth);
879 continue;
880 }
881 if (rth->dst.expires) {
882 /* Entry is expired even if it is in use */
883 if (time_before_eq(jiffies, rth->dst.expires)) {
884 nofree:
885 tmo >>= 1;
886 rthp = &rth->dst.rt_next;
887 /*
888 * We only count entries on
889 * a chain with equal hash inputs once
890 * so that entries for different QOS
891 * levels, and other non-hash input
892 * attributes don't unfairly skew
893 * the length computation
894 */
895 length += has_noalias(rt_hash_table[i].chain, rth);
896 continue;
897 }
898 } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout))
899 goto nofree;
900
901 /* Cleanup aged off entries. */
902 *rthp = rth->dst.rt_next;
903 rt_free(rth);
904 }
905 spin_unlock_bh(rt_hash_lock_addr(i));
906 sum += length;
907 sum2 += length*length;
908 }
909 if (samples) {
910 unsigned long avg = sum / samples;
911 unsigned long sd = int_sqrt(sum2 / samples - avg*avg);
912 rt_chain_length_max = max_t(unsigned long,
913 ip_rt_gc_elasticity,
914 (avg + 4*sd) >> FRACT_BITS);
915 }
916 rover = i;
917 }
918
919 /*
920 * rt_worker_func() is run in process context.
921 * we call rt_check_expire() to scan part of the hash table
922 */
923 static void rt_worker_func(struct work_struct *work)
924 {
925 rt_check_expire();
926 schedule_delayed_work(&expires_work, ip_rt_gc_interval);
927 }
928
929 /*
930 * Perturbation of rt_genid by a small quantity [1..256]
931 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
932 * many times (2^24) without giving recent rt_genid.
933 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
934 */
935 static void rt_cache_invalidate(struct net *net)
936 {
937 unsigned char shuffle;
938
939 get_random_bytes(&shuffle, sizeof(shuffle));
940 atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
941 inetpeer_invalidate_tree(AF_INET);
942 }
943
944 /*
945 * delay < 0 : invalidate cache (fast : entries will be deleted later)
946 * delay >= 0 : invalidate & flush cache (can be long)
947 */
948 void rt_cache_flush(struct net *net, int delay)
949 {
950 rt_cache_invalidate(net);
951 if (delay >= 0)
952 rt_do_flush(net, !in_softirq());
953 }
954
955 /* Flush previous cache invalidated entries from the cache */
956 void rt_cache_flush_batch(struct net *net)
957 {
958 rt_do_flush(net, !in_softirq());
959 }
960
961 static void rt_emergency_hash_rebuild(struct net *net)
962 {
963 if (net_ratelimit())
964 pr_warn("Route hash chain too long!\n");
965 rt_cache_invalidate(net);
966 }
967
968 /*
969 Short description of GC goals.
970
971 We want to build algorithm, which will keep routing cache
972 at some equilibrium point, when number of aged off entries
973 is kept approximately equal to newly generated ones.
974
975 Current expiration strength is variable "expire".
976 We try to adjust it dynamically, so that if networking
977 is idle expires is large enough to keep enough of warm entries,
978 and when load increases it reduces to limit cache size.
979 */
980
981 static int rt_garbage_collect(struct dst_ops *ops)
982 {
983 static unsigned long expire = RT_GC_TIMEOUT;
984 static unsigned long last_gc;
985 static int rover;
986 static int equilibrium;
987 struct rtable *rth;
988 struct rtable __rcu **rthp;
989 unsigned long now = jiffies;
990 int goal;
991 int entries = dst_entries_get_fast(&ipv4_dst_ops);
992
993 /*
994 * Garbage collection is pretty expensive,
995 * do not make it too frequently.
996 */
997
998 RT_CACHE_STAT_INC(gc_total);
999
1000 if (now - last_gc < ip_rt_gc_min_interval &&
1001 entries < ip_rt_max_size) {
1002 RT_CACHE_STAT_INC(gc_ignored);
1003 goto out;
1004 }
1005
1006 entries = dst_entries_get_slow(&ipv4_dst_ops);
1007 /* Calculate number of entries, which we want to expire now. */
1008 goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
1009 if (goal <= 0) {
1010 if (equilibrium < ipv4_dst_ops.gc_thresh)
1011 equilibrium = ipv4_dst_ops.gc_thresh;
1012 goal = entries - equilibrium;
1013 if (goal > 0) {
1014 equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
1015 goal = entries - equilibrium;
1016 }
1017 } else {
1018 /* We are in dangerous area. Try to reduce cache really
1019 * aggressively.
1020 */
1021 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
1022 equilibrium = entries - goal;
1023 }
1024
1025 if (now - last_gc >= ip_rt_gc_min_interval)
1026 last_gc = now;
1027
1028 if (goal <= 0) {
1029 equilibrium += goal;
1030 goto work_done;
1031 }
1032
1033 do {
1034 int i, k;
1035
1036 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
1037 unsigned long tmo = expire;
1038
1039 k = (k + 1) & rt_hash_mask;
1040 rthp = &rt_hash_table[k].chain;
1041 spin_lock_bh(rt_hash_lock_addr(k));
1042 while ((rth = rcu_dereference_protected(*rthp,
1043 lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
1044 if (!rt_is_expired(rth) &&
1045 !rt_may_expire(rth, tmo, expire)) {
1046 tmo >>= 1;
1047 rthp = &rth->dst.rt_next;
1048 continue;
1049 }
1050 *rthp = rth->dst.rt_next;
1051 rt_free(rth);
1052 goal--;
1053 }
1054 spin_unlock_bh(rt_hash_lock_addr(k));
1055 if (goal <= 0)
1056 break;
1057 }
1058 rover = k;
1059
1060 if (goal <= 0)
1061 goto work_done;
1062
1063 /* Goal is not achieved. We stop process if:
1064
1065 - if expire reduced to zero. Otherwise, expire is halfed.
1066 - if table is not full.
1067 - if we are called from interrupt.
1068 - jiffies check is just fallback/debug loop breaker.
1069 We will not spin here for long time in any case.
1070 */
1071
1072 RT_CACHE_STAT_INC(gc_goal_miss);
1073
1074 if (expire == 0)
1075 break;
1076
1077 expire >>= 1;
1078
1079 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1080 goto out;
1081 } while (!in_softirq() && time_before_eq(jiffies, now));
1082
1083 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1084 goto out;
1085 if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
1086 goto out;
1087 if (net_ratelimit())
1088 pr_warn("dst cache overflow\n");
1089 RT_CACHE_STAT_INC(gc_dst_overflow);
1090 return 1;
1091
1092 work_done:
1093 expire += ip_rt_gc_min_interval;
1094 if (expire > ip_rt_gc_timeout ||
1095 dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
1096 dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
1097 expire = ip_rt_gc_timeout;
1098 out: return 0;
1099 }
1100
1101 /*
1102 * Returns number of entries in a hash chain that have different hash_inputs
1103 */
1104 static int slow_chain_length(const struct rtable *head)
1105 {
1106 int length = 0;
1107 const struct rtable *rth = head;
1108
1109 while (rth) {
1110 length += has_noalias(head, rth);
1111 rth = rcu_dereference_protected(rth->dst.rt_next, 1);
1112 }
1113 return length >> FRACT_BITS;
1114 }
1115
1116 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr)
1117 {
1118 static const __be32 inaddr_any = 0;
1119 struct net_device *dev = dst->dev;
1120 const __be32 *pkey = daddr;
1121 const struct rtable *rt;
1122 struct neighbour *n;
1123
1124 rt = (const struct rtable *) dst;
1125
1126 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
1127 pkey = &inaddr_any;
1128 else if (rt->rt_gateway)
1129 pkey = (const __be32 *) &rt->rt_gateway;
1130
1131 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
1132 if (n)
1133 return n;
1134 return neigh_create(&arp_tbl, pkey, dev);
1135 }
1136
1137 static int rt_bind_neighbour(struct rtable *rt)
1138 {
1139 struct neighbour *n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1140 if (IS_ERR(n))
1141 return PTR_ERR(n);
1142 dst_set_neighbour(&rt->dst, n);
1143
1144 return 0;
1145 }
1146
1147 static struct rtable *rt_intern_hash(unsigned int hash, struct rtable *rt,
1148 struct sk_buff *skb, int ifindex)
1149 {
1150 struct rtable *rth, *cand;
1151 struct rtable __rcu **rthp, **candp;
1152 unsigned long now;
1153 u32 min_score;
1154 int chain_length;
1155 int attempts = !in_softirq();
1156
1157 restart:
1158 chain_length = 0;
1159 min_score = ~(u32)0;
1160 cand = NULL;
1161 candp = NULL;
1162 now = jiffies;
1163
1164 if (!rt_caching(dev_net(rt->dst.dev))) {
1165 /*
1166 * If we're not caching, just tell the caller we
1167 * were successful and don't touch the route. The
1168 * caller hold the sole reference to the cache entry, and
1169 * it will be released when the caller is done with it.
1170 * If we drop it here, the callers have no way to resolve routes
1171 * when we're not caching. Instead, just point *rp at rt, so
1172 * the caller gets a single use out of the route
1173 * Note that we do rt_free on this new route entry, so that
1174 * once its refcount hits zero, we are still able to reap it
1175 * (Thanks Alexey)
1176 * Note: To avoid expensive rcu stuff for this uncached dst,
1177 * we set DST_NOCACHE so that dst_release() can free dst without
1178 * waiting a grace period.
1179 */
1180
1181 rt->dst.flags |= DST_NOCACHE;
1182 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1183 int err = rt_bind_neighbour(rt);
1184 if (err) {
1185 if (net_ratelimit())
1186 pr_warn("Neighbour table failure & not caching routes\n");
1187 ip_rt_put(rt);
1188 return ERR_PTR(err);
1189 }
1190 }
1191
1192 goto skip_hashing;
1193 }
1194
1195 rthp = &rt_hash_table[hash].chain;
1196
1197 spin_lock_bh(rt_hash_lock_addr(hash));
1198 while ((rth = rcu_dereference_protected(*rthp,
1199 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1200 if (rt_is_expired(rth)) {
1201 *rthp = rth->dst.rt_next;
1202 rt_free(rth);
1203 continue;
1204 }
1205 if (compare_keys(rth, rt) && compare_netns(rth, rt)) {
1206 /* Put it first */
1207 *rthp = rth->dst.rt_next;
1208 /*
1209 * Since lookup is lockfree, the deletion
1210 * must be visible to another weakly ordered CPU before
1211 * the insertion at the start of the hash chain.
1212 */
1213 rcu_assign_pointer(rth->dst.rt_next,
1214 rt_hash_table[hash].chain);
1215 /*
1216 * Since lookup is lockfree, the update writes
1217 * must be ordered for consistency on SMP.
1218 */
1219 rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1220
1221 dst_use(&rth->dst, now);
1222 spin_unlock_bh(rt_hash_lock_addr(hash));
1223
1224 rt_drop(rt);
1225 if (skb)
1226 skb_dst_set(skb, &rth->dst);
1227 return rth;
1228 }
1229
1230 if (!atomic_read(&rth->dst.__refcnt)) {
1231 u32 score = rt_score(rth);
1232
1233 if (score <= min_score) {
1234 cand = rth;
1235 candp = rthp;
1236 min_score = score;
1237 }
1238 }
1239
1240 chain_length++;
1241
1242 rthp = &rth->dst.rt_next;
1243 }
1244
1245 if (cand) {
1246 /* ip_rt_gc_elasticity used to be average length of chain
1247 * length, when exceeded gc becomes really aggressive.
1248 *
1249 * The second limit is less certain. At the moment it allows
1250 * only 2 entries per bucket. We will see.
1251 */
1252 if (chain_length > ip_rt_gc_elasticity) {
1253 *candp = cand->dst.rt_next;
1254 rt_free(cand);
1255 }
1256 } else {
1257 if (chain_length > rt_chain_length_max &&
1258 slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
1259 struct net *net = dev_net(rt->dst.dev);
1260 int num = ++net->ipv4.current_rt_cache_rebuild_count;
1261 if (!rt_caching(net)) {
1262 pr_warn("%s: %d rebuilds is over limit, route caching disabled\n",
1263 rt->dst.dev->name, num);
1264 }
1265 rt_emergency_hash_rebuild(net);
1266 spin_unlock_bh(rt_hash_lock_addr(hash));
1267
1268 hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1269 ifindex, rt_genid(net));
1270 goto restart;
1271 }
1272 }
1273
1274 /* Try to bind route to arp only if it is output
1275 route or unicast forwarding path.
1276 */
1277 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1278 int err = rt_bind_neighbour(rt);
1279 if (err) {
1280 spin_unlock_bh(rt_hash_lock_addr(hash));
1281
1282 if (err != -ENOBUFS) {
1283 rt_drop(rt);
1284 return ERR_PTR(err);
1285 }
1286
1287 /* Neighbour tables are full and nothing
1288 can be released. Try to shrink route cache,
1289 it is most likely it holds some neighbour records.
1290 */
1291 if (attempts-- > 0) {
1292 int saved_elasticity = ip_rt_gc_elasticity;
1293 int saved_int = ip_rt_gc_min_interval;
1294 ip_rt_gc_elasticity = 1;
1295 ip_rt_gc_min_interval = 0;
1296 rt_garbage_collect(&ipv4_dst_ops);
1297 ip_rt_gc_min_interval = saved_int;
1298 ip_rt_gc_elasticity = saved_elasticity;
1299 goto restart;
1300 }
1301
1302 if (net_ratelimit())
1303 pr_warn("Neighbour table overflow\n");
1304 rt_drop(rt);
1305 return ERR_PTR(-ENOBUFS);
1306 }
1307 }
1308
1309 rt->dst.rt_next = rt_hash_table[hash].chain;
1310
1311 /*
1312 * Since lookup is lockfree, we must make sure
1313 * previous writes to rt are committed to memory
1314 * before making rt visible to other CPUS.
1315 */
1316 rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1317
1318 spin_unlock_bh(rt_hash_lock_addr(hash));
1319
1320 skip_hashing:
1321 if (skb)
1322 skb_dst_set(skb, &rt->dst);
1323 return rt;
1324 }
1325
1326 static atomic_t __rt_peer_genid = ATOMIC_INIT(0);
1327
1328 static u32 rt_peer_genid(void)
1329 {
1330 return atomic_read(&__rt_peer_genid);
1331 }
1332
1333 void rt_bind_peer(struct rtable *rt, __be32 daddr, int create)
1334 {
1335 struct inet_peer *peer;
1336
1337 peer = inet_getpeer_v4(daddr, create);
1338
1339 if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
1340 inet_putpeer(peer);
1341 else
1342 rt->rt_peer_genid = rt_peer_genid();
1343 }
1344
1345 /*
1346 * Peer allocation may fail only in serious out-of-memory conditions. However
1347 * we still can generate some output.
1348 * Random ID selection looks a bit dangerous because we have no chances to
1349 * select ID being unique in a reasonable period of time.
1350 * But broken packet identifier may be better than no packet at all.
1351 */
1352 static void ip_select_fb_ident(struct iphdr *iph)
1353 {
1354 static DEFINE_SPINLOCK(ip_fb_id_lock);
1355 static u32 ip_fallback_id;
1356 u32 salt;
1357
1358 spin_lock_bh(&ip_fb_id_lock);
1359 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1360 iph->id = htons(salt & 0xFFFF);
1361 ip_fallback_id = salt;
1362 spin_unlock_bh(&ip_fb_id_lock);
1363 }
1364
1365 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1366 {
1367 struct rtable *rt = (struct rtable *) dst;
1368
1369 if (rt && !(rt->dst.flags & DST_NOPEER)) {
1370 if (rt->peer == NULL)
1371 rt_bind_peer(rt, rt->rt_dst, 1);
1372
1373 /* If peer is attached to destination, it is never detached,
1374 so that we need not to grab a lock to dereference it.
1375 */
1376 if (rt->peer) {
1377 iph->id = htons(inet_getid(rt->peer, more));
1378 return;
1379 }
1380 } else if (!rt)
1381 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1382 __builtin_return_address(0));
1383
1384 ip_select_fb_ident(iph);
1385 }
1386 EXPORT_SYMBOL(__ip_select_ident);
1387
1388 static void rt_del(unsigned int hash, struct rtable *rt)
1389 {
1390 struct rtable __rcu **rthp;
1391 struct rtable *aux;
1392
1393 rthp = &rt_hash_table[hash].chain;
1394 spin_lock_bh(rt_hash_lock_addr(hash));
1395 ip_rt_put(rt);
1396 while ((aux = rcu_dereference_protected(*rthp,
1397 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1398 if (aux == rt || rt_is_expired(aux)) {
1399 *rthp = aux->dst.rt_next;
1400 rt_free(aux);
1401 continue;
1402 }
1403 rthp = &aux->dst.rt_next;
1404 }
1405 spin_unlock_bh(rt_hash_lock_addr(hash));
1406 }
1407
1408 static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
1409 {
1410 struct rtable *rt = (struct rtable *) dst;
1411 __be32 orig_gw = rt->rt_gateway;
1412 struct neighbour *n, *old_n;
1413
1414 dst_confirm(&rt->dst);
1415
1416 rt->rt_gateway = peer->redirect_learned.a4;
1417
1418 n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
1419 if (IS_ERR(n)) {
1420 rt->rt_gateway = orig_gw;
1421 return;
1422 }
1423 old_n = xchg(&rt->dst._neighbour, n);
1424 if (old_n)
1425 neigh_release(old_n);
1426 if (!(n->nud_state & NUD_VALID)) {
1427 neigh_event_send(n, NULL);
1428 } else {
1429 rt->rt_flags |= RTCF_REDIRECTED;
1430 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
1431 }
1432 }
1433
1434 /* called in rcu_read_lock() section */
1435 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1436 __be32 saddr, struct net_device *dev)
1437 {
1438 int s, i;
1439 struct in_device *in_dev = __in_dev_get_rcu(dev);
1440 __be32 skeys[2] = { saddr, 0 };
1441 int ikeys[2] = { dev->ifindex, 0 };
1442 struct inet_peer *peer;
1443 struct net *net;
1444
1445 if (!in_dev)
1446 return;
1447
1448 net = dev_net(dev);
1449 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1450 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1451 ipv4_is_zeronet(new_gw))
1452 goto reject_redirect;
1453
1454 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1455 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1456 goto reject_redirect;
1457 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1458 goto reject_redirect;
1459 } else {
1460 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1461 goto reject_redirect;
1462 }
1463
1464 for (s = 0; s < 2; s++) {
1465 for (i = 0; i < 2; i++) {
1466 unsigned int hash;
1467 struct rtable __rcu **rthp;
1468 struct rtable *rt;
1469
1470 hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net));
1471
1472 rthp = &rt_hash_table[hash].chain;
1473
1474 while ((rt = rcu_dereference(*rthp)) != NULL) {
1475 rthp = &rt->dst.rt_next;
1476
1477 if (rt->rt_key_dst != daddr ||
1478 rt->rt_key_src != skeys[s] ||
1479 rt->rt_oif != ikeys[i] ||
1480 rt_is_input_route(rt) ||
1481 rt_is_expired(rt) ||
1482 !net_eq(dev_net(rt->dst.dev), net) ||
1483 rt->dst.error ||
1484 rt->dst.dev != dev ||
1485 rt->rt_gateway != old_gw)
1486 continue;
1487
1488 if (!rt->peer)
1489 rt_bind_peer(rt, rt->rt_dst, 1);
1490
1491 peer = rt->peer;
1492 if (peer) {
1493 if (peer->redirect_learned.a4 != new_gw) {
1494 peer->redirect_learned.a4 = new_gw;
1495 atomic_inc(&__rt_peer_genid);
1496 }
1497 check_peer_redir(&rt->dst, peer);
1498 }
1499 }
1500 }
1501 }
1502 return;
1503
1504 reject_redirect:
1505 #ifdef CONFIG_IP_ROUTE_VERBOSE
1506 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1507 pr_info("Redirect from %pI4 on %s about %pI4 ignored\n"
1508 " Advised path = %pI4 -> %pI4\n",
1509 &old_gw, dev->name, &new_gw,
1510 &saddr, &daddr);
1511 #endif
1512 ;
1513 }
1514
1515 static bool peer_pmtu_expired(struct inet_peer *peer)
1516 {
1517 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1518
1519 return orig &&
1520 time_after_eq(jiffies, orig) &&
1521 cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1522 }
1523
1524 static bool peer_pmtu_cleaned(struct inet_peer *peer)
1525 {
1526 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires);
1527
1528 return orig &&
1529 cmpxchg(&peer->pmtu_expires, orig, 0) == orig;
1530 }
1531
1532 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1533 {
1534 struct rtable *rt = (struct rtable *)dst;
1535 struct dst_entry *ret = dst;
1536
1537 if (rt) {
1538 if (dst->obsolete > 0) {
1539 ip_rt_put(rt);
1540 ret = NULL;
1541 } else if (rt->rt_flags & RTCF_REDIRECTED) {
1542 unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1543 rt->rt_oif,
1544 rt_genid(dev_net(dst->dev)));
1545 rt_del(hash, rt);
1546 ret = NULL;
1547 } else if (rt->peer && peer_pmtu_expired(rt->peer)) {
1548 dst_metric_set(dst, RTAX_MTU, rt->peer->pmtu_orig);
1549 }
1550 }
1551 return ret;
1552 }
1553
1554 /*
1555 * Algorithm:
1556 * 1. The first ip_rt_redirect_number redirects are sent
1557 * with exponential backoff, then we stop sending them at all,
1558 * assuming that the host ignores our redirects.
1559 * 2. If we did not see packets requiring redirects
1560 * during ip_rt_redirect_silence, we assume that the host
1561 * forgot redirected route and start to send redirects again.
1562 *
1563 * This algorithm is much cheaper and more intelligent than dumb load limiting
1564 * in icmp.c.
1565 *
1566 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1567 * and "frag. need" (breaks PMTU discovery) in icmp.c.
1568 */
1569
1570 void ip_rt_send_redirect(struct sk_buff *skb)
1571 {
1572 struct rtable *rt = skb_rtable(skb);
1573 struct in_device *in_dev;
1574 struct inet_peer *peer;
1575 int log_martians;
1576
1577 rcu_read_lock();
1578 in_dev = __in_dev_get_rcu(rt->dst.dev);
1579 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1580 rcu_read_unlock();
1581 return;
1582 }
1583 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1584 rcu_read_unlock();
1585
1586 if (!rt->peer)
1587 rt_bind_peer(rt, rt->rt_dst, 1);
1588 peer = rt->peer;
1589 if (!peer) {
1590 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1591 return;
1592 }
1593
1594 /* No redirected packets during ip_rt_redirect_silence;
1595 * reset the algorithm.
1596 */
1597 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1598 peer->rate_tokens = 0;
1599
1600 /* Too many ignored redirects; do not send anything
1601 * set dst.rate_last to the last seen redirected packet.
1602 */
1603 if (peer->rate_tokens >= ip_rt_redirect_number) {
1604 peer->rate_last = jiffies;
1605 return;
1606 }
1607
1608 /* Check for load limit; set rate_last to the latest sent
1609 * redirect.
1610 */
1611 if (peer->rate_tokens == 0 ||
1612 time_after(jiffies,
1613 (peer->rate_last +
1614 (ip_rt_redirect_load << peer->rate_tokens)))) {
1615 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1616 peer->rate_last = jiffies;
1617 ++peer->rate_tokens;
1618 #ifdef CONFIG_IP_ROUTE_VERBOSE
1619 if (log_martians &&
1620 peer->rate_tokens == ip_rt_redirect_number &&
1621 net_ratelimit())
1622 pr_warn("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
1623 &ip_hdr(skb)->saddr, rt->rt_iif,
1624 &rt->rt_dst, &rt->rt_gateway);
1625 #endif
1626 }
1627 }
1628
1629 static int ip_error(struct sk_buff *skb)
1630 {
1631 struct rtable *rt = skb_rtable(skb);
1632 struct inet_peer *peer;
1633 unsigned long now;
1634 bool send;
1635 int code;
1636
1637 switch (rt->dst.error) {
1638 case EINVAL:
1639 default:
1640 goto out;
1641 case EHOSTUNREACH:
1642 code = ICMP_HOST_UNREACH;
1643 break;
1644 case ENETUNREACH:
1645 code = ICMP_NET_UNREACH;
1646 IP_INC_STATS_BH(dev_net(rt->dst.dev),
1647 IPSTATS_MIB_INNOROUTES);
1648 break;
1649 case EACCES:
1650 code = ICMP_PKT_FILTERED;
1651 break;
1652 }
1653
1654 if (!rt->peer)
1655 rt_bind_peer(rt, rt->rt_dst, 1);
1656 peer = rt->peer;
1657
1658 send = true;
1659 if (peer) {
1660 now = jiffies;
1661 peer->rate_tokens += now - peer->rate_last;
1662 if (peer->rate_tokens > ip_rt_error_burst)
1663 peer->rate_tokens = ip_rt_error_burst;
1664 peer->rate_last = now;
1665 if (peer->rate_tokens >= ip_rt_error_cost)
1666 peer->rate_tokens -= ip_rt_error_cost;
1667 else
1668 send = false;
1669 }
1670 if (send)
1671 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1672
1673 out: kfree_skb(skb);
1674 return 0;
1675 }
1676
1677 /*
1678 * The last two values are not from the RFC but
1679 * are needed for AMPRnet AX.25 paths.
1680 */
1681
1682 static const unsigned short mtu_plateau[] =
1683 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1684
1685 static inline unsigned short guess_mtu(unsigned short old_mtu)
1686 {
1687 int i;
1688
1689 for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1690 if (old_mtu > mtu_plateau[i])
1691 return mtu_plateau[i];
1692 return 68;
1693 }
1694
1695 unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
1696 unsigned short new_mtu,
1697 struct net_device *dev)
1698 {
1699 unsigned short old_mtu = ntohs(iph->tot_len);
1700 unsigned short est_mtu = 0;
1701 struct inet_peer *peer;
1702
1703 peer = inet_getpeer_v4(iph->daddr, 1);
1704 if (peer) {
1705 unsigned short mtu = new_mtu;
1706
1707 if (new_mtu < 68 || new_mtu >= old_mtu) {
1708 /* BSD 4.2 derived systems incorrectly adjust
1709 * tot_len by the IP header length, and report
1710 * a zero MTU in the ICMP message.
1711 */
1712 if (mtu == 0 &&
1713 old_mtu >= 68 + (iph->ihl << 2))
1714 old_mtu -= iph->ihl << 2;
1715 mtu = guess_mtu(old_mtu);
1716 }
1717
1718 if (mtu < ip_rt_min_pmtu)
1719 mtu = ip_rt_min_pmtu;
1720 if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
1721 unsigned long pmtu_expires;
1722
1723 pmtu_expires = jiffies + ip_rt_mtu_expires;
1724 if (!pmtu_expires)
1725 pmtu_expires = 1UL;
1726
1727 est_mtu = mtu;
1728 peer->pmtu_learned = mtu;
1729 peer->pmtu_expires = pmtu_expires;
1730 atomic_inc(&__rt_peer_genid);
1731 }
1732
1733 inet_putpeer(peer);
1734 }
1735 return est_mtu ? : new_mtu;
1736 }
1737
1738 static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
1739 {
1740 unsigned long expires = ACCESS_ONCE(peer->pmtu_expires);
1741
1742 if (!expires)
1743 return;
1744 if (time_before(jiffies, expires)) {
1745 u32 orig_dst_mtu = dst_mtu(dst);
1746 if (peer->pmtu_learned < orig_dst_mtu) {
1747 if (!peer->pmtu_orig)
1748 peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU);
1749 dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned);
1750 }
1751 } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires)
1752 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1753 }
1754
1755 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1756 {
1757 struct rtable *rt = (struct rtable *) dst;
1758 struct inet_peer *peer;
1759
1760 dst_confirm(dst);
1761
1762 if (!rt->peer)
1763 rt_bind_peer(rt, rt->rt_dst, 1);
1764 peer = rt->peer;
1765 if (peer) {
1766 unsigned long pmtu_expires = ACCESS_ONCE(peer->pmtu_expires);
1767
1768 if (mtu < ip_rt_min_pmtu)
1769 mtu = ip_rt_min_pmtu;
1770 if (!pmtu_expires || mtu < peer->pmtu_learned) {
1771
1772 pmtu_expires = jiffies + ip_rt_mtu_expires;
1773 if (!pmtu_expires)
1774 pmtu_expires = 1UL;
1775
1776 peer->pmtu_learned = mtu;
1777 peer->pmtu_expires = pmtu_expires;
1778
1779 atomic_inc(&__rt_peer_genid);
1780 rt->rt_peer_genid = rt_peer_genid();
1781 }
1782 check_peer_pmtu(dst, peer);
1783 }
1784 }
1785
1786
1787 static void ipv4_validate_peer(struct rtable *rt)
1788 {
1789 if (rt->rt_peer_genid != rt_peer_genid()) {
1790 struct inet_peer *peer;
1791
1792 if (!rt->peer)
1793 rt_bind_peer(rt, rt->rt_dst, 0);
1794
1795 peer = rt->peer;
1796 if (peer) {
1797 check_peer_pmtu(&rt->dst, peer);
1798
1799 if (peer->redirect_learned.a4 &&
1800 peer->redirect_learned.a4 != rt->rt_gateway)
1801 check_peer_redir(&rt->dst, peer);
1802 }
1803
1804 rt->rt_peer_genid = rt_peer_genid();
1805 }
1806 }
1807
1808 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1809 {
1810 struct rtable *rt = (struct rtable *) dst;
1811
1812 if (rt_is_expired(rt))
1813 return NULL;
1814 ipv4_validate_peer(rt);
1815 return dst;
1816 }
1817
1818 static void ipv4_dst_destroy(struct dst_entry *dst)
1819 {
1820 struct rtable *rt = (struct rtable *) dst;
1821 struct inet_peer *peer = rt->peer;
1822
1823 if (rt->fi) {
1824 fib_info_put(rt->fi);
1825 rt->fi = NULL;
1826 }
1827 if (peer) {
1828 rt->peer = NULL;
1829 inet_putpeer(peer);
1830 }
1831 }
1832
1833
1834 static void ipv4_link_failure(struct sk_buff *skb)
1835 {
1836 struct rtable *rt;
1837
1838 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1839
1840 rt = skb_rtable(skb);
1841 if (rt && rt->peer && peer_pmtu_cleaned(rt->peer))
1842 dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig);
1843 }
1844
1845 static int ip_rt_bug(struct sk_buff *skb)
1846 {
1847 printk(KERN_DEBUG "ip_rt_bug: %pI4 -> %pI4, %s\n",
1848 &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1849 skb->dev ? skb->dev->name : "?");
1850 kfree_skb(skb);
1851 WARN_ON(1);
1852 return 0;
1853 }
1854
1855 /*
1856 We do not cache source address of outgoing interface,
1857 because it is used only by IP RR, TS and SRR options,
1858 so that it out of fast path.
1859
1860 BTW remember: "addr" is allowed to be not aligned
1861 in IP options!
1862 */
1863
1864 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1865 {
1866 __be32 src;
1867
1868 if (rt_is_output_route(rt))
1869 src = ip_hdr(skb)->saddr;
1870 else {
1871 struct fib_result res;
1872 struct flowi4 fl4;
1873 struct iphdr *iph;
1874
1875 iph = ip_hdr(skb);
1876
1877 memset(&fl4, 0, sizeof(fl4));
1878 fl4.daddr = iph->daddr;
1879 fl4.saddr = iph->saddr;
1880 fl4.flowi4_tos = RT_TOS(iph->tos);
1881 fl4.flowi4_oif = rt->dst.dev->ifindex;
1882 fl4.flowi4_iif = skb->dev->ifindex;
1883 fl4.flowi4_mark = skb->mark;
1884
1885 rcu_read_lock();
1886 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1887 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1888 else
1889 src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1890 RT_SCOPE_UNIVERSE);
1891 rcu_read_unlock();
1892 }
1893 memcpy(addr, &src, 4);
1894 }
1895
1896 #ifdef CONFIG_IP_ROUTE_CLASSID
1897 static void set_class_tag(struct rtable *rt, u32 tag)
1898 {
1899 if (!(rt->dst.tclassid & 0xFFFF))
1900 rt->dst.tclassid |= tag & 0xFFFF;
1901 if (!(rt->dst.tclassid & 0xFFFF0000))
1902 rt->dst.tclassid |= tag & 0xFFFF0000;
1903 }
1904 #endif
1905
1906 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1907 {
1908 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1909
1910 if (advmss == 0) {
1911 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1912 ip_rt_min_advmss);
1913 if (advmss > 65535 - 40)
1914 advmss = 65535 - 40;
1915 }
1916 return advmss;
1917 }
1918
1919 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1920 {
1921 const struct rtable *rt = (const struct rtable *) dst;
1922 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1923
1924 if (mtu && rt_is_output_route(rt))
1925 return mtu;
1926
1927 mtu = dst->dev->mtu;
1928
1929 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1930
1931 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1932 mtu = 576;
1933 }
1934
1935 if (mtu > IP_MAX_MTU)
1936 mtu = IP_MAX_MTU;
1937
1938 return mtu;
1939 }
1940
1941 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1942 struct fib_info *fi)
1943 {
1944 struct inet_peer *peer;
1945 int create = 0;
1946
1947 /* If a peer entry exists for this destination, we must hook
1948 * it up in order to get at cached metrics.
1949 */
1950 if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
1951 create = 1;
1952
1953 rt->peer = peer = inet_getpeer_v4(rt->rt_dst, create);
1954 if (peer) {
1955 rt->rt_peer_genid = rt_peer_genid();
1956 if (inet_metrics_new(peer))
1957 memcpy(peer->metrics, fi->fib_metrics,
1958 sizeof(u32) * RTAX_MAX);
1959 dst_init_metrics(&rt->dst, peer->metrics, false);
1960
1961 check_peer_pmtu(&rt->dst, peer);
1962
1963 if (peer->redirect_learned.a4 &&
1964 peer->redirect_learned.a4 != rt->rt_gateway) {
1965 rt->rt_gateway = peer->redirect_learned.a4;
1966 rt->rt_flags |= RTCF_REDIRECTED;
1967 }
1968 } else {
1969 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1970 rt->fi = fi;
1971 atomic_inc(&fi->fib_clntref);
1972 }
1973 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1974 }
1975 }
1976
1977 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1978 const struct fib_result *res,
1979 struct fib_info *fi, u16 type, u32 itag)
1980 {
1981 struct dst_entry *dst = &rt->dst;
1982
1983 if (fi) {
1984 if (FIB_RES_GW(*res) &&
1985 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1986 rt->rt_gateway = FIB_RES_GW(*res);
1987 rt_init_metrics(rt, fl4, fi);
1988 #ifdef CONFIG_IP_ROUTE_CLASSID
1989 dst->tclassid = FIB_RES_NH(*res).nh_tclassid;
1990 #endif
1991 }
1992
1993 if (dst_mtu(dst) > IP_MAX_MTU)
1994 dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);
1995 if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40)
1996 dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40);
1997
1998 #ifdef CONFIG_IP_ROUTE_CLASSID
1999 #ifdef CONFIG_IP_MULTIPLE_TABLES
2000 set_class_tag(rt, fib_rules_tclass(res));
2001 #endif
2002 set_class_tag(rt, itag);
2003 #endif
2004 }
2005
2006 static struct rtable *rt_dst_alloc(struct net_device *dev,
2007 bool nopolicy, bool noxfrm)
2008 {
2009 return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
2010 DST_HOST |
2011 (nopolicy ? DST_NOPOLICY : 0) |
2012 (noxfrm ? DST_NOXFRM : 0));
2013 }
2014
2015 /* called in rcu_read_lock() section */
2016 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2017 u8 tos, struct net_device *dev, int our)
2018 {
2019 unsigned int hash;
2020 struct rtable *rth;
2021 __be32 spec_dst;
2022 struct in_device *in_dev = __in_dev_get_rcu(dev);
2023 u32 itag = 0;
2024 int err;
2025
2026 /* Primary sanity checks. */
2027
2028 if (in_dev == NULL)
2029 return -EINVAL;
2030
2031 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
2032 ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
2033 goto e_inval;
2034
2035 if (ipv4_is_zeronet(saddr)) {
2036 if (!ipv4_is_local_multicast(daddr))
2037 goto e_inval;
2038 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2039 } else {
2040 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst,
2041 &itag);
2042 if (err < 0)
2043 goto e_err;
2044 }
2045 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
2046 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2047 if (!rth)
2048 goto e_nobufs;
2049
2050 #ifdef CONFIG_IP_ROUTE_CLASSID
2051 rth->dst.tclassid = itag;
2052 #endif
2053 rth->dst.output = ip_rt_bug;
2054
2055 rth->rt_key_dst = daddr;
2056 rth->rt_key_src = saddr;
2057 rth->rt_genid = rt_genid(dev_net(dev));
2058 rth->rt_flags = RTCF_MULTICAST;
2059 rth->rt_type = RTN_MULTICAST;
2060 rth->rt_key_tos = tos;
2061 rth->rt_dst = daddr;
2062 rth->rt_src = saddr;
2063 rth->rt_route_iif = dev->ifindex;
2064 rth->rt_iif = dev->ifindex;
2065 rth->rt_oif = 0;
2066 rth->rt_mark = skb->mark;
2067 rth->rt_gateway = daddr;
2068 rth->rt_spec_dst= spec_dst;
2069 rth->rt_peer_genid = 0;
2070 rth->peer = NULL;
2071 rth->fi = NULL;
2072 if (our) {
2073 rth->dst.input= ip_local_deliver;
2074 rth->rt_flags |= RTCF_LOCAL;
2075 }
2076
2077 #ifdef CONFIG_IP_MROUTE
2078 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
2079 rth->dst.input = ip_mr_input;
2080 #endif
2081 RT_CACHE_STAT_INC(in_slow_mc);
2082
2083 hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
2084 rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
2085 return IS_ERR(rth) ? PTR_ERR(rth) : 0;
2086
2087 e_nobufs:
2088 return -ENOBUFS;
2089 e_inval:
2090 return -EINVAL;
2091 e_err:
2092 return err;
2093 }
2094
2095
2096 static void ip_handle_martian_source(struct net_device *dev,
2097 struct in_device *in_dev,
2098 struct sk_buff *skb,
2099 __be32 daddr,
2100 __be32 saddr)
2101 {
2102 RT_CACHE_STAT_INC(in_martian_src);
2103 #ifdef CONFIG_IP_ROUTE_VERBOSE
2104 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
2105 /*
2106 * RFC1812 recommendation, if source is martian,
2107 * the only hint is MAC header.
2108 */
2109 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
2110 &daddr, &saddr, dev->name);
2111 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
2112 print_hex_dump(KERN_WARNING, "ll header: ",
2113 DUMP_PREFIX_OFFSET, 16, 1,
2114 skb_mac_header(skb),
2115 dev->hard_header_len, true);
2116 }
2117 }
2118 #endif
2119 }
2120
2121 /* called in rcu_read_lock() section */
2122 static int __mkroute_input(struct sk_buff *skb,
2123 const struct fib_result *res,
2124 struct in_device *in_dev,
2125 __be32 daddr, __be32 saddr, u32 tos,
2126 struct rtable **result)
2127 {
2128 struct rtable *rth;
2129 int err;
2130 struct in_device *out_dev;
2131 unsigned int flags = 0;
2132 __be32 spec_dst;
2133 u32 itag;
2134
2135 /* get a working reference to the output device */
2136 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
2137 if (out_dev == NULL) {
2138 if (net_ratelimit())
2139 pr_crit("Bug in ip_route_input_slow(). Please report.\n");
2140 return -EINVAL;
2141 }
2142
2143
2144 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
2145 in_dev->dev, &spec_dst, &itag);
2146 if (err < 0) {
2147 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
2148 saddr);
2149
2150 goto cleanup;
2151 }
2152
2153 if (err)
2154 flags |= RTCF_DIRECTSRC;
2155
2156 if (out_dev == in_dev && err &&
2157 (IN_DEV_SHARED_MEDIA(out_dev) ||
2158 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
2159 flags |= RTCF_DOREDIRECT;
2160
2161 if (skb->protocol != htons(ETH_P_IP)) {
2162 /* Not IP (i.e. ARP). Do not create route, if it is
2163 * invalid for proxy arp. DNAT routes are always valid.
2164 *
2165 * Proxy arp feature have been extended to allow, ARP
2166 * replies back to the same interface, to support
2167 * Private VLAN switch technologies. See arp.c.
2168 */
2169 if (out_dev == in_dev &&
2170 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2171 err = -EINVAL;
2172 goto cleanup;
2173 }
2174 }
2175
2176 rth = rt_dst_alloc(out_dev->dev,
2177 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2178 IN_DEV_CONF_GET(out_dev, NOXFRM));
2179 if (!rth) {
2180 err = -ENOBUFS;
2181 goto cleanup;
2182 }
2183
2184 rth->rt_key_dst = daddr;
2185 rth->rt_key_src = saddr;
2186 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
2187 rth->rt_flags = flags;
2188 rth->rt_type = res->type;
2189 rth->rt_key_tos = tos;
2190 rth->rt_dst = daddr;
2191 rth->rt_src = saddr;
2192 rth->rt_route_iif = in_dev->dev->ifindex;
2193 rth->rt_iif = in_dev->dev->ifindex;
2194 rth->rt_oif = 0;
2195 rth->rt_mark = skb->mark;
2196 rth->rt_gateway = daddr;
2197 rth->rt_spec_dst= spec_dst;
2198 rth->rt_peer_genid = 0;
2199 rth->peer = NULL;
2200 rth->fi = NULL;
2201
2202 rth->dst.input = ip_forward;
2203 rth->dst.output = ip_output;
2204
2205 rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
2206
2207 *result = rth;
2208 err = 0;
2209 cleanup:
2210 return err;
2211 }
2212
2213 static int ip_mkroute_input(struct sk_buff *skb,
2214 struct fib_result *res,
2215 const struct flowi4 *fl4,
2216 struct in_device *in_dev,
2217 __be32 daddr, __be32 saddr, u32 tos)
2218 {
2219 struct rtable *rth = NULL;
2220 int err;
2221 unsigned int hash;
2222
2223 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2224 if (res->fi && res->fi->fib_nhs > 1)
2225 fib_select_multipath(res);
2226 #endif
2227
2228 /* create a routing cache entry */
2229 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
2230 if (err)
2231 return err;
2232
2233 /* put it into the cache */
2234 hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
2235 rt_genid(dev_net(rth->dst.dev)));
2236 rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
2237 if (IS_ERR(rth))
2238 return PTR_ERR(rth);
2239 return 0;
2240 }
2241
2242 /*
2243 * NOTE. We drop all the packets that has local source
2244 * addresses, because every properly looped back packet
2245 * must have correct destination already attached by output routine.
2246 *
2247 * Such approach solves two big problems:
2248 * 1. Not simplex devices are handled properly.
2249 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2250 * called with rcu_read_lock()
2251 */
2252
2253 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2254 u8 tos, struct net_device *dev)
2255 {
2256 struct fib_result res;
2257 struct in_device *in_dev = __in_dev_get_rcu(dev);
2258 struct flowi4 fl4;
2259 unsigned int flags = 0;
2260 u32 itag = 0;
2261 struct rtable *rth;
2262 unsigned int hash;
2263 __be32 spec_dst;
2264 int err = -EINVAL;
2265 struct net *net = dev_net(dev);
2266
2267 /* IP on this device is disabled. */
2268
2269 if (!in_dev)
2270 goto out;
2271
2272 /* Check for the most weird martians, which can be not detected
2273 by fib_lookup.
2274 */
2275
2276 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
2277 ipv4_is_loopback(saddr))
2278 goto martian_source;
2279
2280 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2281 goto brd_input;
2282
2283 /* Accept zero addresses only to limited broadcast;
2284 * I even do not know to fix it or not. Waiting for complains :-)
2285 */
2286 if (ipv4_is_zeronet(saddr))
2287 goto martian_source;
2288
2289 if (ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr))
2290 goto martian_destination;
2291
2292 /*
2293 * Now we are ready to route packet.
2294 */
2295 fl4.flowi4_oif = 0;
2296 fl4.flowi4_iif = dev->ifindex;
2297 fl4.flowi4_mark = skb->mark;
2298 fl4.flowi4_tos = tos;
2299 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2300 fl4.daddr = daddr;
2301 fl4.saddr = saddr;
2302 err = fib_lookup(net, &fl4, &res);
2303 if (err != 0) {
2304 if (!IN_DEV_FORWARD(in_dev))
2305 goto e_hostunreach;
2306 goto no_route;
2307 }
2308
2309 RT_CACHE_STAT_INC(in_slow_tot);
2310
2311 if (res.type == RTN_BROADCAST)
2312 goto brd_input;
2313
2314 if (res.type == RTN_LOCAL) {
2315 err = fib_validate_source(skb, saddr, daddr, tos,
2316 net->loopback_dev->ifindex,
2317 dev, &spec_dst, &itag);
2318 if (err < 0)
2319 goto martian_source_keep_err;
2320 if (err)
2321 flags |= RTCF_DIRECTSRC;
2322 spec_dst = daddr;
2323 goto local_input;
2324 }
2325
2326 if (!IN_DEV_FORWARD(in_dev))
2327 goto e_hostunreach;
2328 if (res.type != RTN_UNICAST)
2329 goto martian_destination;
2330
2331 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2332 out: return err;
2333
2334 brd_input:
2335 if (skb->protocol != htons(ETH_P_IP))
2336 goto e_inval;
2337
2338 if (ipv4_is_zeronet(saddr))
2339 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2340 else {
2341 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst,
2342 &itag);
2343 if (err < 0)
2344 goto martian_source_keep_err;
2345 if (err)
2346 flags |= RTCF_DIRECTSRC;
2347 }
2348 flags |= RTCF_BROADCAST;
2349 res.type = RTN_BROADCAST;
2350 RT_CACHE_STAT_INC(in_brd);
2351
2352 local_input:
2353 rth = rt_dst_alloc(net->loopback_dev,
2354 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2355 if (!rth)
2356 goto e_nobufs;
2357
2358 rth->dst.input= ip_local_deliver;
2359 rth->dst.output= ip_rt_bug;
2360 #ifdef CONFIG_IP_ROUTE_CLASSID
2361 rth->dst.tclassid = itag;
2362 #endif
2363
2364 rth->rt_key_dst = daddr;
2365 rth->rt_key_src = saddr;
2366 rth->rt_genid = rt_genid(net);
2367 rth->rt_flags = flags|RTCF_LOCAL;
2368 rth->rt_type = res.type;
2369 rth->rt_key_tos = tos;
2370 rth->rt_dst = daddr;
2371 rth->rt_src = saddr;
2372 #ifdef CONFIG_IP_ROUTE_CLASSID
2373 rth->dst.tclassid = itag;
2374 #endif
2375 rth->rt_route_iif = dev->ifindex;
2376 rth->rt_iif = dev->ifindex;
2377 rth->rt_oif = 0;
2378 rth->rt_mark = skb->mark;
2379 rth->rt_gateway = daddr;
2380 rth->rt_spec_dst= spec_dst;
2381 rth->rt_peer_genid = 0;
2382 rth->peer = NULL;
2383 rth->fi = NULL;
2384 if (res.type == RTN_UNREACHABLE) {
2385 rth->dst.input= ip_error;
2386 rth->dst.error= -err;
2387 rth->rt_flags &= ~RTCF_LOCAL;
2388 }
2389 hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2390 rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2391 err = 0;
2392 if (IS_ERR(rth))
2393 err = PTR_ERR(rth);
2394 goto out;
2395
2396 no_route:
2397 RT_CACHE_STAT_INC(in_no_route);
2398 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2399 res.type = RTN_UNREACHABLE;
2400 if (err == -ESRCH)
2401 err = -ENETUNREACH;
2402 goto local_input;
2403
2404 /*
2405 * Do not cache martian addresses: they should be logged (RFC1812)
2406 */
2407 martian_destination:
2408 RT_CACHE_STAT_INC(in_martian_dst);
2409 #ifdef CONFIG_IP_ROUTE_VERBOSE
2410 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
2411 pr_warn("martian destination %pI4 from %pI4, dev %s\n",
2412 &daddr, &saddr, dev->name);
2413 #endif
2414
2415 e_hostunreach:
2416 err = -EHOSTUNREACH;
2417 goto out;
2418
2419 e_inval:
2420 err = -EINVAL;
2421 goto out;
2422
2423 e_nobufs:
2424 err = -ENOBUFS;
2425 goto out;
2426
2427 martian_source:
2428 err = -EINVAL;
2429 martian_source_keep_err:
2430 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2431 goto out;
2432 }
2433
2434 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2435 u8 tos, struct net_device *dev, bool noref)
2436 {
2437 struct rtable *rth;
2438 unsigned int hash;
2439 int iif = dev->ifindex;
2440 struct net *net;
2441 int res;
2442
2443 net = dev_net(dev);
2444
2445 rcu_read_lock();
2446
2447 if (!rt_caching(net))
2448 goto skip_cache;
2449
2450 tos &= IPTOS_RT_MASK;
2451 hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2452
2453 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2454 rth = rcu_dereference(rth->dst.rt_next)) {
2455 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2456 ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2457 (rth->rt_route_iif ^ iif) |
2458 (rth->rt_key_tos ^ tos)) == 0 &&
2459 rth->rt_mark == skb->mark &&
2460 net_eq(dev_net(rth->dst.dev), net) &&
2461 !rt_is_expired(rth)) {
2462 ipv4_validate_peer(rth);
2463 if (noref) {
2464 dst_use_noref(&rth->dst, jiffies);
2465 skb_dst_set_noref(skb, &rth->dst);
2466 } else {
2467 dst_use(&rth->dst, jiffies);
2468 skb_dst_set(skb, &rth->dst);
2469 }
2470 RT_CACHE_STAT_INC(in_hit);
2471 rcu_read_unlock();
2472 return 0;
2473 }
2474 RT_CACHE_STAT_INC(in_hlist_search);
2475 }
2476
2477 skip_cache:
2478 /* Multicast recognition logic is moved from route cache to here.
2479 The problem was that too many Ethernet cards have broken/missing
2480 hardware multicast filters :-( As result the host on multicasting
2481 network acquires a lot of useless route cache entries, sort of
2482 SDR messages from all the world. Now we try to get rid of them.
2483 Really, provided software IP multicast filter is organized
2484 reasonably (at least, hashed), it does not result in a slowdown
2485 comparing with route cache reject entries.
2486 Note, that multicast routers are not affected, because
2487 route cache entry is created eventually.
2488 */
2489 if (ipv4_is_multicast(daddr)) {
2490 struct in_device *in_dev = __in_dev_get_rcu(dev);
2491
2492 if (in_dev) {
2493 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2494 ip_hdr(skb)->protocol);
2495 if (our
2496 #ifdef CONFIG_IP_MROUTE
2497 ||
2498 (!ipv4_is_local_multicast(daddr) &&
2499 IN_DEV_MFORWARD(in_dev))
2500 #endif
2501 ) {
2502 int res = ip_route_input_mc(skb, daddr, saddr,
2503 tos, dev, our);
2504 rcu_read_unlock();
2505 return res;
2506 }
2507 }
2508 rcu_read_unlock();
2509 return -EINVAL;
2510 }
2511 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2512 rcu_read_unlock();
2513 return res;
2514 }
2515 EXPORT_SYMBOL(ip_route_input_common);
2516
2517 /* called with rcu_read_lock() */
2518 static struct rtable *__mkroute_output(const struct fib_result *res,
2519 const struct flowi4 *fl4,
2520 __be32 orig_daddr, __be32 orig_saddr,
2521 int orig_oif, __u8 orig_rtos,
2522 struct net_device *dev_out,
2523 unsigned int flags)
2524 {
2525 struct fib_info *fi = res->fi;
2526 struct in_device *in_dev;
2527 u16 type = res->type;
2528 struct rtable *rth;
2529
2530 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2531 return ERR_PTR(-EINVAL);
2532
2533 if (ipv4_is_lbcast(fl4->daddr))
2534 type = RTN_BROADCAST;
2535 else if (ipv4_is_multicast(fl4->daddr))
2536 type = RTN_MULTICAST;
2537 else if (ipv4_is_zeronet(fl4->daddr))
2538 return ERR_PTR(-EINVAL);
2539
2540 if (dev_out->flags & IFF_LOOPBACK)
2541 flags |= RTCF_LOCAL;
2542
2543 in_dev = __in_dev_get_rcu(dev_out);
2544 if (!in_dev)
2545 return ERR_PTR(-EINVAL);
2546
2547 if (type == RTN_BROADCAST) {
2548 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2549 fi = NULL;
2550 } else if (type == RTN_MULTICAST) {
2551 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2552 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2553 fl4->flowi4_proto))
2554 flags &= ~RTCF_LOCAL;
2555 /* If multicast route do not exist use
2556 * default one, but do not gateway in this case.
2557 * Yes, it is hack.
2558 */
2559 if (fi && res->prefixlen < 4)
2560 fi = NULL;
2561 }
2562
2563 rth = rt_dst_alloc(dev_out,
2564 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2565 IN_DEV_CONF_GET(in_dev, NOXFRM));
2566 if (!rth)
2567 return ERR_PTR(-ENOBUFS);
2568
2569 rth->dst.output = ip_output;
2570
2571 rth->rt_key_dst = orig_daddr;
2572 rth->rt_key_src = orig_saddr;
2573 rth->rt_genid = rt_genid(dev_net(dev_out));
2574 rth->rt_flags = flags;
2575 rth->rt_type = type;
2576 rth->rt_key_tos = orig_rtos;
2577 rth->rt_dst = fl4->daddr;
2578 rth->rt_src = fl4->saddr;
2579 rth->rt_route_iif = 0;
2580 rth->rt_iif = orig_oif ? : dev_out->ifindex;
2581 rth->rt_oif = orig_oif;
2582 rth->rt_mark = fl4->flowi4_mark;
2583 rth->rt_gateway = fl4->daddr;
2584 rth->rt_spec_dst= fl4->saddr;
2585 rth->rt_peer_genid = 0;
2586 rth->peer = NULL;
2587 rth->fi = NULL;
2588
2589 RT_CACHE_STAT_INC(out_slow_tot);
2590
2591 if (flags & RTCF_LOCAL) {
2592 rth->dst.input = ip_local_deliver;
2593 rth->rt_spec_dst = fl4->daddr;
2594 }
2595 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2596 rth->rt_spec_dst = fl4->saddr;
2597 if (flags & RTCF_LOCAL &&
2598 !(dev_out->flags & IFF_LOOPBACK)) {
2599 rth->dst.output = ip_mc_output;
2600 RT_CACHE_STAT_INC(out_slow_mc);
2601 }
2602 #ifdef CONFIG_IP_MROUTE
2603 if (type == RTN_MULTICAST) {
2604 if (IN_DEV_MFORWARD(in_dev) &&
2605 !ipv4_is_local_multicast(fl4->daddr)) {
2606 rth->dst.input = ip_mr_input;
2607 rth->dst.output = ip_mc_output;
2608 }
2609 }
2610 #endif
2611 }
2612
2613 rt_set_nexthop(rth, fl4, res, fi, type, 0);
2614
2615 return rth;
2616 }
2617
2618 /*
2619 * Major route resolver routine.
2620 * called with rcu_read_lock();
2621 */
2622
2623 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4)
2624 {
2625 struct net_device *dev_out = NULL;
2626 __u8 tos = RT_FL_TOS(fl4);
2627 unsigned int flags = 0;
2628 struct fib_result res;
2629 struct rtable *rth;
2630 __be32 orig_daddr;
2631 __be32 orig_saddr;
2632 int orig_oif;
2633
2634 res.fi = NULL;
2635 #ifdef CONFIG_IP_MULTIPLE_TABLES
2636 res.r = NULL;
2637 #endif
2638
2639 orig_daddr = fl4->daddr;
2640 orig_saddr = fl4->saddr;
2641 orig_oif = fl4->flowi4_oif;
2642
2643 fl4->flowi4_iif = net->loopback_dev->ifindex;
2644 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2645 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2646 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2647
2648 rcu_read_lock();
2649 if (fl4->saddr) {
2650 rth = ERR_PTR(-EINVAL);
2651 if (ipv4_is_multicast(fl4->saddr) ||
2652 ipv4_is_lbcast(fl4->saddr) ||
2653 ipv4_is_zeronet(fl4->saddr))
2654 goto out;
2655
2656 /* I removed check for oif == dev_out->oif here.
2657 It was wrong for two reasons:
2658 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2659 is assigned to multiple interfaces.
2660 2. Moreover, we are allowed to send packets with saddr
2661 of another iface. --ANK
2662 */
2663
2664 if (fl4->flowi4_oif == 0 &&
2665 (ipv4_is_multicast(fl4->daddr) ||
2666 ipv4_is_lbcast(fl4->daddr))) {
2667 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2668 dev_out = __ip_dev_find(net, fl4->saddr, false);
2669 if (dev_out == NULL)
2670 goto out;
2671
2672 /* Special hack: user can direct multicasts
2673 and limited broadcast via necessary interface
2674 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2675 This hack is not just for fun, it allows
2676 vic,vat and friends to work.
2677 They bind socket to loopback, set ttl to zero
2678 and expect that it will work.
2679 From the viewpoint of routing cache they are broken,
2680 because we are not allowed to build multicast path
2681 with loopback source addr (look, routing cache
2682 cannot know, that ttl is zero, so that packet
2683 will not leave this host and route is valid).
2684 Luckily, this hack is good workaround.
2685 */
2686
2687 fl4->flowi4_oif = dev_out->ifindex;
2688 goto make_route;
2689 }
2690
2691 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2692 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2693 if (!__ip_dev_find(net, fl4->saddr, false))
2694 goto out;
2695 }
2696 }
2697
2698
2699 if (fl4->flowi4_oif) {
2700 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2701 rth = ERR_PTR(-ENODEV);
2702 if (dev_out == NULL)
2703 goto out;
2704
2705 /* RACE: Check return value of inet_select_addr instead. */
2706 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2707 rth = ERR_PTR(-ENETUNREACH);
2708 goto out;
2709 }
2710 if (ipv4_is_local_multicast(fl4->daddr) ||
2711 ipv4_is_lbcast(fl4->daddr)) {
2712 if (!fl4->saddr)
2713 fl4->saddr = inet_select_addr(dev_out, 0,
2714 RT_SCOPE_LINK);
2715 goto make_route;
2716 }
2717 if (fl4->saddr) {
2718 if (ipv4_is_multicast(fl4->daddr))
2719 fl4->saddr = inet_select_addr(dev_out, 0,
2720 fl4->flowi4_scope);
2721 else if (!fl4->daddr)
2722 fl4->saddr = inet_select_addr(dev_out, 0,
2723 RT_SCOPE_HOST);
2724 }
2725 }
2726
2727 if (!fl4->daddr) {
2728 fl4->daddr = fl4->saddr;
2729 if (!fl4->daddr)
2730 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2731 dev_out = net->loopback_dev;
2732 fl4->flowi4_oif = net->loopback_dev->ifindex;
2733 res.type = RTN_LOCAL;
2734 flags |= RTCF_LOCAL;
2735 goto make_route;
2736 }
2737
2738 if (fib_lookup(net, fl4, &res)) {
2739 res.fi = NULL;
2740 if (fl4->flowi4_oif) {
2741 /* Apparently, routing tables are wrong. Assume,
2742 that the destination is on link.
2743
2744 WHY? DW.
2745 Because we are allowed to send to iface
2746 even if it has NO routes and NO assigned
2747 addresses. When oif is specified, routing
2748 tables are looked up with only one purpose:
2749 to catch if destination is gatewayed, rather than
2750 direct. Moreover, if MSG_DONTROUTE is set,
2751 we send packet, ignoring both routing tables
2752 and ifaddr state. --ANK
2753
2754
2755 We could make it even if oif is unknown,
2756 likely IPv6, but we do not.
2757 */
2758
2759 if (fl4->saddr == 0)
2760 fl4->saddr = inet_select_addr(dev_out, 0,
2761 RT_SCOPE_LINK);
2762 res.type = RTN_UNICAST;
2763 goto make_route;
2764 }
2765 rth = ERR_PTR(-ENETUNREACH);
2766 goto out;
2767 }
2768
2769 if (res.type == RTN_LOCAL) {
2770 if (!fl4->saddr) {
2771 if (res.fi->fib_prefsrc)
2772 fl4->saddr = res.fi->fib_prefsrc;
2773 else
2774 fl4->saddr = fl4->daddr;
2775 }
2776 dev_out = net->loopback_dev;
2777 fl4->flowi4_oif = dev_out->ifindex;
2778 res.fi = NULL;
2779 flags |= RTCF_LOCAL;
2780 goto make_route;
2781 }
2782
2783 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2784 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2785 fib_select_multipath(&res);
2786 else
2787 #endif
2788 if (!res.prefixlen &&
2789 res.table->tb_num_default > 1 &&
2790 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2791 fib_select_default(&res);
2792
2793 if (!fl4->saddr)
2794 fl4->saddr = FIB_RES_PREFSRC(net, res);
2795
2796 dev_out = FIB_RES_DEV(res);
2797 fl4->flowi4_oif = dev_out->ifindex;
2798
2799
2800 make_route:
2801 rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif,
2802 tos, dev_out, flags);
2803 if (!IS_ERR(rth)) {
2804 unsigned int hash;
2805
2806 hash = rt_hash(orig_daddr, orig_saddr, orig_oif,
2807 rt_genid(dev_net(dev_out)));
2808 rth = rt_intern_hash(hash, rth, NULL, orig_oif);
2809 }
2810
2811 out:
2812 rcu_read_unlock();
2813 return rth;
2814 }
2815
2816 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
2817 {
2818 struct rtable *rth;
2819 unsigned int hash;
2820
2821 if (!rt_caching(net))
2822 goto slow_output;
2823
2824 hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2825
2826 rcu_read_lock_bh();
2827 for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2828 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2829 if (rth->rt_key_dst == flp4->daddr &&
2830 rth->rt_key_src == flp4->saddr &&
2831 rt_is_output_route(rth) &&
2832 rth->rt_oif == flp4->flowi4_oif &&
2833 rth->rt_mark == flp4->flowi4_mark &&
2834 !((rth->rt_key_tos ^ flp4->flowi4_tos) &
2835 (IPTOS_RT_MASK | RTO_ONLINK)) &&
2836 net_eq(dev_net(rth->dst.dev), net) &&
2837 !rt_is_expired(rth)) {
2838 ipv4_validate_peer(rth);
2839 dst_use(&rth->dst, jiffies);
2840 RT_CACHE_STAT_INC(out_hit);
2841 rcu_read_unlock_bh();
2842 if (!flp4->saddr)
2843 flp4->saddr = rth->rt_src;
2844 if (!flp4->daddr)
2845 flp4->daddr = rth->rt_dst;
2846 return rth;
2847 }
2848 RT_CACHE_STAT_INC(out_hlist_search);
2849 }
2850 rcu_read_unlock_bh();
2851
2852 slow_output:
2853 return ip_route_output_slow(net, flp4);
2854 }
2855 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2856
2857 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2858 {
2859 return NULL;
2860 }
2861
2862 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2863 {
2864 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2865
2866 return mtu ? : dst->dev->mtu;
2867 }
2868
2869 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2870 {
2871 }
2872
2873 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2874 unsigned long old)
2875 {
2876 return NULL;
2877 }
2878
2879 static struct dst_ops ipv4_dst_blackhole_ops = {
2880 .family = AF_INET,
2881 .protocol = cpu_to_be16(ETH_P_IP),
2882 .destroy = ipv4_dst_destroy,
2883 .check = ipv4_blackhole_dst_check,
2884 .mtu = ipv4_blackhole_mtu,
2885 .default_advmss = ipv4_default_advmss,
2886 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2887 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2888 .neigh_lookup = ipv4_neigh_lookup,
2889 };
2890
2891 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2892 {
2893 struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
2894 struct rtable *ort = (struct rtable *) dst_orig;
2895
2896 if (rt) {
2897 struct dst_entry *new = &rt->dst;
2898
2899 new->__use = 1;
2900 new->input = dst_discard;
2901 new->output = dst_discard;
2902 dst_copy_metrics(new, &ort->dst);
2903
2904 new->dev = ort->dst.dev;
2905 if (new->dev)
2906 dev_hold(new->dev);
2907
2908 rt->rt_key_dst = ort->rt_key_dst;
2909 rt->rt_key_src = ort->rt_key_src;
2910 rt->rt_key_tos = ort->rt_key_tos;
2911 rt->rt_route_iif = ort->rt_route_iif;
2912 rt->rt_iif = ort->rt_iif;
2913 rt->rt_oif = ort->rt_oif;
2914 rt->rt_mark = ort->rt_mark;
2915
2916 rt->rt_genid = rt_genid(net);
2917 rt->rt_flags = ort->rt_flags;
2918 rt->rt_type = ort->rt_type;
2919 rt->rt_dst = ort->rt_dst;
2920 rt->rt_src = ort->rt_src;
2921 rt->rt_gateway = ort->rt_gateway;
2922 rt->rt_spec_dst = ort->rt_spec_dst;
2923 rt->peer = ort->peer;
2924 if (rt->peer)
2925 atomic_inc(&rt->peer->refcnt);
2926 rt->fi = ort->fi;
2927 if (rt->fi)
2928 atomic_inc(&rt->fi->fib_clntref);
2929
2930 dst_free(new);
2931 }
2932
2933 dst_release(dst_orig);
2934
2935 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2936 }
2937
2938 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2939 struct sock *sk)
2940 {
2941 struct rtable *rt = __ip_route_output_key(net, flp4);
2942
2943 if (IS_ERR(rt))
2944 return rt;
2945
2946 if (flp4->flowi4_proto)
2947 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2948 flowi4_to_flowi(flp4),
2949 sk, 0);
2950
2951 return rt;
2952 }
2953 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2954
2955 static int rt_fill_info(struct net *net,
2956 struct sk_buff *skb, u32 pid, u32 seq, int event,
2957 int nowait, unsigned int flags)
2958 {
2959 struct rtable *rt = skb_rtable(skb);
2960 struct rtmsg *r;
2961 struct nlmsghdr *nlh;
2962 unsigned long expires = 0;
2963 const struct inet_peer *peer = rt->peer;
2964 u32 id = 0, ts = 0, tsage = 0, error;
2965
2966 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2967 if (nlh == NULL)
2968 return -EMSGSIZE;
2969
2970 r = nlmsg_data(nlh);
2971 r->rtm_family = AF_INET;
2972 r->rtm_dst_len = 32;
2973 r->rtm_src_len = 0;
2974 r->rtm_tos = rt->rt_key_tos;
2975 r->rtm_table = RT_TABLE_MAIN;
2976 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2977 goto nla_put_failure;
2978 r->rtm_type = rt->rt_type;
2979 r->rtm_scope = RT_SCOPE_UNIVERSE;
2980 r->rtm_protocol = RTPROT_UNSPEC;
2981 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2982 if (rt->rt_flags & RTCF_NOTIFY)
2983 r->rtm_flags |= RTM_F_NOTIFY;
2984
2985 if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2986 goto nla_put_failure;
2987 if (rt->rt_key_src) {
2988 r->rtm_src_len = 32;
2989 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src))
2990 goto nla_put_failure;
2991 }
2992 if (rt->dst.dev &&
2993 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2994 goto nla_put_failure;
2995 #ifdef CONFIG_IP_ROUTE_CLASSID
2996 if (rt->dst.tclassid &&
2997 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2998 goto nla_put_failure;
2999 #endif
3000 if (rt_is_input_route(rt)) {
3001 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_spec_dst))
3002 goto nla_put_failure;
3003 } else if (rt->rt_src != rt->rt_key_src) {
3004 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src))
3005 goto nla_put_failure;
3006 }
3007 if (rt->rt_dst != rt->rt_gateway &&
3008 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
3009 goto nla_put_failure;
3010
3011 if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
3012 goto nla_put_failure;
3013
3014 if (rt->rt_mark &&
3015 nla_put_be32(skb, RTA_MARK, rt->rt_mark))
3016 goto nla_put_failure;
3017
3018 error = rt->dst.error;
3019 if (peer) {
3020 inet_peer_refcheck(rt->peer);
3021 id = atomic_read(&peer->ip_id_count) & 0xffff;
3022 if (peer->tcp_ts_stamp) {
3023 ts = peer->tcp_ts;
3024 tsage = get_seconds() - peer->tcp_ts_stamp;
3025 }
3026 expires = ACCESS_ONCE(peer->pmtu_expires);
3027 if (expires) {
3028 if (time_before(jiffies, expires))
3029 expires -= jiffies;
3030 else
3031 expires = 0;
3032 }
3033 }
3034
3035 if (rt_is_input_route(rt)) {
3036 #ifdef CONFIG_IP_MROUTE
3037 __be32 dst = rt->rt_dst;
3038
3039 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
3040 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
3041 int err = ipmr_get_route(net, skb,
3042 rt->rt_src, rt->rt_dst,
3043 r, nowait);
3044 if (err <= 0) {
3045 if (!nowait) {
3046 if (err == 0)
3047 return 0;
3048 goto nla_put_failure;
3049 } else {
3050 if (err == -EMSGSIZE)
3051 goto nla_put_failure;
3052 error = err;
3053 }
3054 }
3055 } else
3056 #endif
3057 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
3058 goto nla_put_failure;
3059 }
3060
3061 if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage,
3062 expires, error) < 0)
3063 goto nla_put_failure;
3064
3065 return nlmsg_end(skb, nlh);
3066
3067 nla_put_failure:
3068 nlmsg_cancel(skb, nlh);
3069 return -EMSGSIZE;
3070 }
3071
3072 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
3073 {
3074 struct net *net = sock_net(in_skb->sk);
3075 struct rtmsg *rtm;
3076 struct nlattr *tb[RTA_MAX+1];
3077 struct rtable *rt = NULL;
3078 __be32 dst = 0;
3079 __be32 src = 0;
3080 u32 iif;
3081 int err;
3082 int mark;
3083 struct sk_buff *skb;
3084
3085 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
3086 if (err < 0)
3087 goto errout;
3088
3089 rtm = nlmsg_data(nlh);
3090
3091 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3092 if (skb == NULL) {
3093 err = -ENOBUFS;
3094 goto errout;
3095 }
3096
3097 /* Reserve room for dummy headers, this skb can pass
3098 through good chunk of routing engine.
3099 */
3100 skb_reset_mac_header(skb);
3101 skb_reset_network_header(skb);
3102
3103 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
3104 ip_hdr(skb)->protocol = IPPROTO_ICMP;
3105 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
3106
3107 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
3108 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
3109 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3110 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3111
3112 if (iif) {
3113 struct net_device *dev;
3114
3115 dev = __dev_get_by_index(net, iif);
3116 if (dev == NULL) {
3117 err = -ENODEV;
3118 goto errout_free;
3119 }
3120
3121 skb->protocol = htons(ETH_P_IP);
3122 skb->dev = dev;
3123 skb->mark = mark;
3124 local_bh_disable();
3125 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
3126 local_bh_enable();
3127
3128 rt = skb_rtable(skb);
3129 if (err == 0 && rt->dst.error)
3130 err = -rt->dst.error;
3131 } else {
3132 struct flowi4 fl4 = {
3133 .daddr = dst,
3134 .saddr = src,
3135 .flowi4_tos = rtm->rtm_tos,
3136 .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
3137 .flowi4_mark = mark,
3138 };
3139 rt = ip_route_output_key(net, &fl4);
3140
3141 err = 0;
3142 if (IS_ERR(rt))
3143 err = PTR_ERR(rt);
3144 }
3145
3146 if (err)
3147 goto errout_free;
3148
3149 skb_dst_set(skb, &rt->dst);
3150 if (rtm->rtm_flags & RTM_F_NOTIFY)
3151 rt->rt_flags |= RTCF_NOTIFY;
3152
3153 err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
3154 RTM_NEWROUTE, 0, 0);
3155 if (err <= 0)
3156 goto errout_free;
3157
3158 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
3159 errout:
3160 return err;
3161
3162 errout_free:
3163 kfree_skb(skb);
3164 goto errout;
3165 }
3166
3167 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
3168 {
3169 struct rtable *rt;
3170 int h, s_h;
3171 int idx, s_idx;
3172 struct net *net;
3173
3174 net = sock_net(skb->sk);
3175
3176 s_h = cb->args[0];
3177 if (s_h < 0)
3178 s_h = 0;
3179 s_idx = idx = cb->args[1];
3180 for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
3181 if (!rt_hash_table[h].chain)
3182 continue;
3183 rcu_read_lock_bh();
3184 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
3185 rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
3186 if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
3187 continue;
3188 if (rt_is_expired(rt))
3189 continue;
3190 skb_dst_set_noref(skb, &rt->dst);
3191 if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
3192 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
3193 1, NLM_F_MULTI) <= 0) {
3194 skb_dst_drop(skb);
3195 rcu_read_unlock_bh();
3196 goto done;
3197 }
3198 skb_dst_drop(skb);
3199 }
3200 rcu_read_unlock_bh();
3201 }
3202
3203 done:
3204 cb->args[0] = h;
3205 cb->args[1] = idx;
3206 return skb->len;
3207 }
3208
3209 void ip_rt_multicast_event(struct in_device *in_dev)
3210 {
3211 rt_cache_flush(dev_net(in_dev->dev), 0);
3212 }
3213
3214 #ifdef CONFIG_SYSCTL
3215 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
3216 void __user *buffer,
3217 size_t *lenp, loff_t *ppos)
3218 {
3219 if (write) {
3220 int flush_delay;
3221 ctl_table ctl;
3222 struct net *net;
3223
3224 memcpy(&ctl, __ctl, sizeof(ctl));
3225 ctl.data = &flush_delay;
3226 proc_dointvec(&ctl, write, buffer, lenp, ppos);
3227
3228 net = (struct net *)__ctl->extra1;
3229 rt_cache_flush(net, flush_delay);
3230 return 0;
3231 }
3232
3233 return -EINVAL;
3234 }
3235
3236 static ctl_table ipv4_route_table[] = {
3237 {
3238 .procname = "gc_thresh",
3239 .data = &ipv4_dst_ops.gc_thresh,
3240 .maxlen = sizeof(int),
3241 .mode = 0644,
3242 .proc_handler = proc_dointvec,
3243 },
3244 {
3245 .procname = "max_size",
3246 .data = &ip_rt_max_size,
3247 .maxlen = sizeof(int),
3248 .mode = 0644,
3249 .proc_handler = proc_dointvec,
3250 },
3251 {
3252 /* Deprecated. Use gc_min_interval_ms */
3253
3254 .procname = "gc_min_interval",
3255 .data = &ip_rt_gc_min_interval,
3256 .maxlen = sizeof(int),
3257 .mode = 0644,
3258 .proc_handler = proc_dointvec_jiffies,
3259 },
3260 {
3261 .procname = "gc_min_interval_ms",
3262 .data = &ip_rt_gc_min_interval,
3263 .maxlen = sizeof(int),
3264 .mode = 0644,
3265 .proc_handler = proc_dointvec_ms_jiffies,
3266 },
3267 {
3268 .procname = "gc_timeout",
3269 .data = &ip_rt_gc_timeout,
3270 .maxlen = sizeof(int),
3271 .mode = 0644,
3272 .proc_handler = proc_dointvec_jiffies,
3273 },
3274 {
3275 .procname = "gc_interval",
3276 .data = &ip_rt_gc_interval,
3277 .maxlen = sizeof(int),
3278 .mode = 0644,
3279 .proc_handler = proc_dointvec_jiffies,
3280 },
3281 {
3282 .procname = "redirect_load",
3283 .data = &ip_rt_redirect_load,
3284 .maxlen = sizeof(int),
3285 .mode = 0644,
3286 .proc_handler = proc_dointvec,
3287 },
3288 {
3289 .procname = "redirect_number",
3290 .data = &ip_rt_redirect_number,
3291 .maxlen = sizeof(int),
3292 .mode = 0644,
3293 .proc_handler = proc_dointvec,
3294 },
3295 {
3296 .procname = "redirect_silence",
3297 .data = &ip_rt_redirect_silence,
3298 .maxlen = sizeof(int),
3299 .mode = 0644,
3300 .proc_handler = proc_dointvec,
3301 },
3302 {
3303 .procname = "error_cost",
3304 .data = &ip_rt_error_cost,
3305 .maxlen = sizeof(int),
3306 .mode = 0644,
3307 .proc_handler = proc_dointvec,
3308 },
3309 {
3310 .procname = "error_burst",
3311 .data = &ip_rt_error_burst,
3312 .maxlen = sizeof(int),
3313 .mode = 0644,
3314 .proc_handler = proc_dointvec,
3315 },
3316 {
3317 .procname = "gc_elasticity",
3318 .data = &ip_rt_gc_elasticity,
3319 .maxlen = sizeof(int),
3320 .mode = 0644,
3321 .proc_handler = proc_dointvec,
3322 },
3323 {
3324 .procname = "mtu_expires",
3325 .data = &ip_rt_mtu_expires,
3326 .maxlen = sizeof(int),
3327 .mode = 0644,
3328 .proc_handler = proc_dointvec_jiffies,
3329 },
3330 {
3331 .procname = "min_pmtu",
3332 .data = &ip_rt_min_pmtu,
3333 .maxlen = sizeof(int),
3334 .mode = 0644,
3335 .proc_handler = proc_dointvec,
3336 },
3337 {
3338 .procname = "min_adv_mss",
3339 .data = &ip_rt_min_advmss,
3340 .maxlen = sizeof(int),
3341 .mode = 0644,
3342 .proc_handler = proc_dointvec,
3343 },
3344 { }
3345 };
3346
3347 static struct ctl_table ipv4_route_flush_table[] = {
3348 {
3349 .procname = "flush",
3350 .maxlen = sizeof(int),
3351 .mode = 0200,
3352 .proc_handler = ipv4_sysctl_rtcache_flush,
3353 },
3354 { },
3355 };
3356
3357 static __net_init int sysctl_route_net_init(struct net *net)
3358 {
3359 struct ctl_table *tbl;
3360
3361 tbl = ipv4_route_flush_table;
3362 if (!net_eq(net, &init_net)) {
3363 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3364 if (tbl == NULL)
3365 goto err_dup;
3366 }
3367 tbl[0].extra1 = net;
3368
3369 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3370 if (net->ipv4.route_hdr == NULL)
3371 goto err_reg;
3372 return 0;
3373
3374 err_reg:
3375 if (tbl != ipv4_route_flush_table)
3376 kfree(tbl);
3377 err_dup:
3378 return -ENOMEM;
3379 }
3380
3381 static __net_exit void sysctl_route_net_exit(struct net *net)
3382 {
3383 struct ctl_table *tbl;
3384
3385 tbl = net->ipv4.route_hdr->ctl_table_arg;
3386 unregister_net_sysctl_table(net->ipv4.route_hdr);
3387 BUG_ON(tbl == ipv4_route_flush_table);
3388 kfree(tbl);
3389 }
3390
3391 static __net_initdata struct pernet_operations sysctl_route_ops = {
3392 .init = sysctl_route_net_init,
3393 .exit = sysctl_route_net_exit,
3394 };
3395 #endif
3396
3397 static __net_init int rt_genid_init(struct net *net)
3398 {
3399 get_random_bytes(&net->ipv4.rt_genid,
3400 sizeof(net->ipv4.rt_genid));
3401 get_random_bytes(&net->ipv4.dev_addr_genid,
3402 sizeof(net->ipv4.dev_addr_genid));
3403 return 0;
3404 }
3405
3406 static __net_initdata struct pernet_operations rt_genid_ops = {
3407 .init = rt_genid_init,
3408 };
3409
3410
3411 #ifdef CONFIG_IP_ROUTE_CLASSID
3412 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3413 #endif /* CONFIG_IP_ROUTE_CLASSID */
3414
3415 static __initdata unsigned long rhash_entries;
3416 static int __init set_rhash_entries(char *str)
3417 {
3418 if (!str)
3419 return 0;
3420 rhash_entries = simple_strtoul(str, &str, 0);
3421 return 1;
3422 }
3423 __setup("rhash_entries=", set_rhash_entries);
3424
3425 int __init ip_rt_init(void)
3426 {
3427 int rc = 0;
3428
3429 #ifdef CONFIG_IP_ROUTE_CLASSID
3430 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3431 if (!ip_rt_acct)
3432 panic("IP: failed to allocate ip_rt_acct\n");
3433 #endif
3434
3435 ipv4_dst_ops.kmem_cachep =
3436 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3437 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3438
3439 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3440
3441 if (dst_entries_init(&ipv4_dst_ops) < 0)
3442 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3443
3444 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3445 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3446
3447 rt_hash_table = (struct rt_hash_bucket *)
3448 alloc_large_system_hash("IP route cache",
3449 sizeof(struct rt_hash_bucket),
3450 rhash_entries,
3451 (totalram_pages >= 128 * 1024) ?
3452 15 : 17,
3453 0,
3454 &rt_hash_log,
3455 &rt_hash_mask,
3456 rhash_entries ? 0 : 512 * 1024);
3457 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3458 rt_hash_lock_init();
3459
3460 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3461 ip_rt_max_size = (rt_hash_mask + 1) * 16;
3462
3463 devinet_init();
3464 ip_fib_init();
3465
3466 INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3467 expires_ljiffies = jiffies;
3468 schedule_delayed_work(&expires_work,
3469 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3470
3471 if (ip_rt_proc_init())
3472 pr_err("Unable to create route proc files\n");
3473 #ifdef CONFIG_XFRM
3474 xfrm_init();
3475 xfrm4_init(ip_rt_max_size);
3476 #endif
3477 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3478
3479 #ifdef CONFIG_SYSCTL
3480 register_pernet_subsys(&sysctl_route_ops);
3481 #endif
3482 register_pernet_subsys(&rt_genid_ops);
3483 return rc;
3484 }
3485
3486 #ifdef CONFIG_SYSCTL
3487 /*
3488 * We really need to sanitize the damn ipv4 init order, then all
3489 * this nonsense will go away.
3490 */
3491 void __init ip_static_sysctl_init(void)
3492 {
3493 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3494 }
3495 #endif
Linux 2.6 libata-dev (mirror)