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sched: s/sched_latency/sched_min_granularity
[usb.git] / net / ipv4 / route.c
blobc7ca94bd152cc945c99c1ab63fcf7d3985d5f639
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * ROUTE - implementation of the IP router.
7 *
8 * Version: $Id: route.c,v 1.103 2002/01/12 07:44:09 davem Exp $
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Alan Cox, <gw4pts@gw4pts.ampr.org>
13 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
14 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
15 *
16 * Fixes:
17 * Alan Cox : Verify area fixes.
18 * Alan Cox : cli() protects routing changes
19 * Rui Oliveira : ICMP routing table updates
20 * (rco@di.uminho.pt) Routing table insertion and update
21 * Linus Torvalds : Rewrote bits to be sensible
22 * Alan Cox : Added BSD route gw semantics
23 * Alan Cox : Super /proc >4K
24 * Alan Cox : MTU in route table
25 * Alan Cox : MSS actually. Also added the window
26 * clamper.
27 * Sam Lantinga : Fixed route matching in rt_del()
28 * Alan Cox : Routing cache support.
29 * Alan Cox : Removed compatibility cruft.
30 * Alan Cox : RTF_REJECT support.
31 * Alan Cox : TCP irtt support.
32 * Jonathan Naylor : Added Metric support.
33 * Miquel van Smoorenburg : BSD API fixes.
34 * Miquel van Smoorenburg : Metrics.
35 * Alan Cox : Use __u32 properly
36 * Alan Cox : Aligned routing errors more closely with BSD
37 * our system is still very different.
38 * Alan Cox : Faster /proc handling
39 * Alexey Kuznetsov : Massive rework to support tree based routing,
40 * routing caches and better behaviour.
41 *
42 * Olaf Erb : irtt wasn't being copied right.
43 * Bjorn Ekwall : Kerneld route support.
44 * Alan Cox : Multicast fixed (I hope)
45 * Pavel Krauz : Limited broadcast fixed
46 * Mike McLagan : Routing by source
47 * Alexey Kuznetsov : End of old history. Split to fib.c and
48 * route.c and rewritten from scratch.
49 * Andi Kleen : Load-limit warning messages.
50 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
51 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
52 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
53 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
54 * Marc Boucher : routing by fwmark
55 * Robert Olsson : Added rt_cache statistics
56 * Arnaldo C. Melo : Convert proc stuff to seq_file
57 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
58 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
59 * Ilia Sotnikov : Removed TOS from hash calculations
60 *
61 * This program is free software; you can redistribute it and/or
62 * modify it under the terms of the GNU General Public License
63 * as published by the Free Software Foundation; either version
64 * 2 of the License, or (at your option) any later version.
65 */
66
67 #include <linux/module.h>
68 #include <asm/uaccess.h>
69 #include <asm/system.h>
70 #include <linux/bitops.h>
71 #include <linux/types.h>
72 #include <linux/kernel.h>
73 #include <linux/mm.h>
74 #include <linux/bootmem.h>
75 #include <linux/string.h>
76 #include <linux/socket.h>
77 #include <linux/sockios.h>
78 #include <linux/errno.h>
79 #include <linux/in.h>
80 #include <linux/inet.h>
81 #include <linux/netdevice.h>
82 #include <linux/proc_fs.h>
83 #include <linux/init.h>
84 #include <linux/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 <net/protocol.h>
95 #include <net/ip.h>
96 #include <net/route.h>
97 #include <net/inetpeer.h>
98 #include <net/sock.h>
99 #include <net/ip_fib.h>
100 #include <net/arp.h>
101 #include <net/tcp.h>
102 #include <net/icmp.h>
103 #include <net/xfrm.h>
104 #include <net/netevent.h>
105 #include <net/rtnetlink.h>
106 #ifdef CONFIG_SYSCTL
107 #include <linux/sysctl.h>
108 #endif
109
110 #define RT_FL_TOS(oldflp) \
111 ((u32)(oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
112
113 #define IP_MAX_MTU 0xFFF0
114
115 #define RT_GC_TIMEOUT (300*HZ)
116
117 static int ip_rt_min_delay = 2 * HZ;
118 static int ip_rt_max_delay = 10 * HZ;
119 static int ip_rt_max_size;
120 static int ip_rt_gc_timeout = RT_GC_TIMEOUT;
121 static int ip_rt_gc_interval = 60 * HZ;
122 static int ip_rt_gc_min_interval = HZ / 2;
123 static int ip_rt_redirect_number = 9;
124 static int ip_rt_redirect_load = HZ / 50;
125 static int ip_rt_redirect_silence = ((HZ / 50) << (9 + 1));
126 static int ip_rt_error_cost = HZ;
127 static int ip_rt_error_burst = 5 * HZ;
128 static int ip_rt_gc_elasticity = 8;
129 static int ip_rt_mtu_expires = 10 * 60 * HZ;
130 static int ip_rt_min_pmtu = 512 + 20 + 20;
131 static int ip_rt_min_advmss = 256;
132 static int ip_rt_secret_interval = 10 * 60 * HZ;
133 static unsigned long rt_deadline;
134
135 #define RTprint(a...) printk(KERN_DEBUG a)
136
137 static struct timer_list rt_flush_timer;
138 static struct timer_list rt_periodic_timer;
139 static struct timer_list rt_secret_timer;
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 void ipv4_dst_destroy(struct dst_entry *dst);
147 static void ipv4_dst_ifdown(struct dst_entry *dst,
148 struct net_device *dev, int how);
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(void);
153
154
155 static struct dst_ops ipv4_dst_ops = {
156 .family = AF_INET,
157 .protocol = __constant_htons(ETH_P_IP),
158 .gc = rt_garbage_collect,
159 .check = ipv4_dst_check,
160 .destroy = ipv4_dst_destroy,
161 .ifdown = ipv4_dst_ifdown,
162 .negative_advice = ipv4_negative_advice,
163 .link_failure = ipv4_link_failure,
164 .update_pmtu = ip_rt_update_pmtu,
165 .entry_size = sizeof(struct rtable),
166 };
167
168 #define ECN_OR_COST(class) TC_PRIO_##class
169
170 const __u8 ip_tos2prio[16] = {
171 TC_PRIO_BESTEFFORT,
172 ECN_OR_COST(FILLER),
173 TC_PRIO_BESTEFFORT,
174 ECN_OR_COST(BESTEFFORT),
175 TC_PRIO_BULK,
176 ECN_OR_COST(BULK),
177 TC_PRIO_BULK,
178 ECN_OR_COST(BULK),
179 TC_PRIO_INTERACTIVE,
180 ECN_OR_COST(INTERACTIVE),
181 TC_PRIO_INTERACTIVE,
182 ECN_OR_COST(INTERACTIVE),
183 TC_PRIO_INTERACTIVE_BULK,
184 ECN_OR_COST(INTERACTIVE_BULK),
185 TC_PRIO_INTERACTIVE_BULK,
186 ECN_OR_COST(INTERACTIVE_BULK)
187 };
188
189
190 /*
191 * Route cache.
192 */
193
194 /* The locking scheme is rather straight forward:
195 *
196 * 1) Read-Copy Update protects the buckets of the central route hash.
197 * 2) Only writers remove entries, and they hold the lock
198 * as they look at rtable reference counts.
199 * 3) Only readers acquire references to rtable entries,
200 * they do so with atomic increments and with the
201 * lock held.
202 */
203
204 struct rt_hash_bucket {
205 struct rtable *chain;
206 };
207 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
208 defined(CONFIG_PROVE_LOCKING)
209 /*
210 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
211 * The size of this table is a power of two and depends on the number of CPUS.
212 * (on lockdep we have a quite big spinlock_t, so keep the size down there)
213 */
214 #ifdef CONFIG_LOCKDEP
215 # define RT_HASH_LOCK_SZ 256
216 #else
217 # if NR_CPUS >= 32
218 # define RT_HASH_LOCK_SZ 4096
219 # elif NR_CPUS >= 16
220 # define RT_HASH_LOCK_SZ 2048
221 # elif NR_CPUS >= 8
222 # define RT_HASH_LOCK_SZ 1024
223 # elif NR_CPUS >= 4
224 # define RT_HASH_LOCK_SZ 512
225 # else
226 # define RT_HASH_LOCK_SZ 256
227 # endif
228 #endif
229
230 static spinlock_t *rt_hash_locks;
231 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
232 # define rt_hash_lock_init() { \
233 int i; \
234 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ, GFP_KERNEL); \
235 if (!rt_hash_locks) panic("IP: failed to allocate rt_hash_locks\n"); \
236 for (i = 0; i < RT_HASH_LOCK_SZ; i++) \
237 spin_lock_init(&rt_hash_locks[i]); \
238 }
239 #else
240 # define rt_hash_lock_addr(slot) NULL
241 # define rt_hash_lock_init()
242 #endif
243
244 static struct rt_hash_bucket *rt_hash_table;
245 static unsigned rt_hash_mask;
246 static int rt_hash_log;
247 static unsigned int rt_hash_rnd;
248
249 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
250 #define RT_CACHE_STAT_INC(field) \
251 (__raw_get_cpu_var(rt_cache_stat).field++)
252
253 static int rt_intern_hash(unsigned hash, struct rtable *rth,
254 struct rtable **res);
255
256 static unsigned int rt_hash_code(u32 daddr, u32 saddr)
257 {
258 return (jhash_2words(daddr, saddr, rt_hash_rnd)
259 & rt_hash_mask);
260 }
261
262 #define rt_hash(daddr, saddr, idx) \
263 rt_hash_code((__force u32)(__be32)(daddr),\
264 (__force u32)(__be32)(saddr) ^ ((idx) << 5))
265
266 #ifdef CONFIG_PROC_FS
267 struct rt_cache_iter_state {
268 int bucket;
269 };
270
271 static struct rtable *rt_cache_get_first(struct seq_file *seq)
272 {
273 struct rtable *r = NULL;
274 struct rt_cache_iter_state *st = seq->private;
275
276 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
277 rcu_read_lock_bh();
278 r = rt_hash_table[st->bucket].chain;
279 if (r)
280 break;
281 rcu_read_unlock_bh();
282 }
283 return r;
284 }
285
286 static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r)
287 {
288 struct rt_cache_iter_state *st = rcu_dereference(seq->private);
289
290 r = r->u.dst.rt_next;
291 while (!r) {
292 rcu_read_unlock_bh();
293 if (--st->bucket < 0)
294 break;
295 rcu_read_lock_bh();
296 r = rt_hash_table[st->bucket].chain;
297 }
298 return r;
299 }
300
301 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
302 {
303 struct rtable *r = rt_cache_get_first(seq);
304
305 if (r)
306 while (pos && (r = rt_cache_get_next(seq, r)))
307 --pos;
308 return pos ? NULL : r;
309 }
310
311 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
312 {
313 return *pos ? rt_cache_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
314 }
315
316 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
317 {
318 struct rtable *r = NULL;
319
320 if (v == SEQ_START_TOKEN)
321 r = rt_cache_get_first(seq);
322 else
323 r = rt_cache_get_next(seq, v);
324 ++*pos;
325 return r;
326 }
327
328 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
329 {
330 if (v && v != SEQ_START_TOKEN)
331 rcu_read_unlock_bh();
332 }
333
334 static int rt_cache_seq_show(struct seq_file *seq, void *v)
335 {
336 if (v == SEQ_START_TOKEN)
337 seq_printf(seq, "%-127s\n",
338 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
339 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
340 "HHUptod\tSpecDst");
341 else {
342 struct rtable *r = v;
343 char temp[256];
344
345 sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
346 "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X",
347 r->u.dst.dev ? r->u.dst.dev->name : "*",
348 (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
349 r->rt_flags, atomic_read(&r->u.dst.__refcnt),
350 r->u.dst.__use, 0, (unsigned long)r->rt_src,
351 (dst_metric(&r->u.dst, RTAX_ADVMSS) ?
352 (int)dst_metric(&r->u.dst, RTAX_ADVMSS) + 40 : 0),
353 dst_metric(&r->u.dst, RTAX_WINDOW),
354 (int)((dst_metric(&r->u.dst, RTAX_RTT) >> 3) +
355 dst_metric(&r->u.dst, RTAX_RTTVAR)),
356 r->fl.fl4_tos,
357 r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
358 r->u.dst.hh ? (r->u.dst.hh->hh_output ==
359 dev_queue_xmit) : 0,
360 r->rt_spec_dst);
361 seq_printf(seq, "%-127s\n", temp);
362 }
363 return 0;
364 }
365
366 static const struct seq_operations rt_cache_seq_ops = {
367 .start = rt_cache_seq_start,
368 .next = rt_cache_seq_next,
369 .stop = rt_cache_seq_stop,
370 .show = rt_cache_seq_show,
371 };
372
373 static int rt_cache_seq_open(struct inode *inode, struct file *file)
374 {
375 struct seq_file *seq;
376 int rc = -ENOMEM;
377 struct rt_cache_iter_state *s;
378
379 s = kzalloc(sizeof(*s), GFP_KERNEL);
380 if (!s)
381 goto out;
382 rc = seq_open(file, &rt_cache_seq_ops);
383 if (rc)
384 goto out_kfree;
385 seq = file->private_data;
386 seq->private = s;
387 out:
388 return rc;
389 out_kfree:
390 kfree(s);
391 goto out;
392 }
393
394 static const struct file_operations rt_cache_seq_fops = {
395 .owner = THIS_MODULE,
396 .open = rt_cache_seq_open,
397 .read = seq_read,
398 .llseek = seq_lseek,
399 .release = seq_release_private,
400 };
401
402
403 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
404 {
405 int cpu;
406
407 if (*pos == 0)
408 return SEQ_START_TOKEN;
409
410 for (cpu = *pos-1; cpu < NR_CPUS; ++cpu) {
411 if (!cpu_possible(cpu))
412 continue;
413 *pos = cpu+1;
414 return &per_cpu(rt_cache_stat, cpu);
415 }
416 return NULL;
417 }
418
419 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
420 {
421 int cpu;
422
423 for (cpu = *pos; cpu < NR_CPUS; ++cpu) {
424 if (!cpu_possible(cpu))
425 continue;
426 *pos = cpu+1;
427 return &per_cpu(rt_cache_stat, cpu);
428 }
429 return NULL;
430
431 }
432
433 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
434 {
435
436 }
437
438 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
439 {
440 struct rt_cache_stat *st = v;
441
442 if (v == SEQ_START_TOKEN) {
443 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");
444 return 0;
445 }
446
447 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
448 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
449 atomic_read(&ipv4_dst_ops.entries),
450 st->in_hit,
451 st->in_slow_tot,
452 st->in_slow_mc,
453 st->in_no_route,
454 st->in_brd,
455 st->in_martian_dst,
456 st->in_martian_src,
457
458 st->out_hit,
459 st->out_slow_tot,
460 st->out_slow_mc,
461
462 st->gc_total,
463 st->gc_ignored,
464 st->gc_goal_miss,
465 st->gc_dst_overflow,
466 st->in_hlist_search,
467 st->out_hlist_search
468 );
469 return 0;
470 }
471
472 static const struct seq_operations rt_cpu_seq_ops = {
473 .start = rt_cpu_seq_start,
474 .next = rt_cpu_seq_next,
475 .stop = rt_cpu_seq_stop,
476 .show = rt_cpu_seq_show,
477 };
478
479
480 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
481 {
482 return seq_open(file, &rt_cpu_seq_ops);
483 }
484
485 static const struct file_operations rt_cpu_seq_fops = {
486 .owner = THIS_MODULE,
487 .open = rt_cpu_seq_open,
488 .read = seq_read,
489 .llseek = seq_lseek,
490 .release = seq_release,
491 };
492
493 #endif /* CONFIG_PROC_FS */
494
495 static __inline__ void rt_free(struct rtable *rt)
496 {
497 call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
498 }
499
500 static __inline__ void rt_drop(struct rtable *rt)
501 {
502 ip_rt_put(rt);
503 call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
504 }
505
506 static __inline__ int rt_fast_clean(struct rtable *rth)
507 {
508 /* Kill broadcast/multicast entries very aggresively, if they
509 collide in hash table with more useful entries */
510 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
511 rth->fl.iif && rth->u.dst.rt_next;
512 }
513
514 static __inline__ int rt_valuable(struct rtable *rth)
515 {
516 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
517 rth->u.dst.expires;
518 }
519
520 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
521 {
522 unsigned long age;
523 int ret = 0;
524
525 if (atomic_read(&rth->u.dst.__refcnt))
526 goto out;
527
528 ret = 1;
529 if (rth->u.dst.expires &&
530 time_after_eq(jiffies, rth->u.dst.expires))
531 goto out;
532
533 age = jiffies - rth->u.dst.lastuse;
534 ret = 0;
535 if ((age <= tmo1 && !rt_fast_clean(rth)) ||
536 (age <= tmo2 && rt_valuable(rth)))
537 goto out;
538 ret = 1;
539 out: return ret;
540 }
541
542 /* Bits of score are:
543 * 31: very valuable
544 * 30: not quite useless
545 * 29..0: usage counter
546 */
547 static inline u32 rt_score(struct rtable *rt)
548 {
549 u32 score = jiffies - rt->u.dst.lastuse;
550
551 score = ~score & ~(3<<30);
552
553 if (rt_valuable(rt))
554 score |= (1<<31);
555
556 if (!rt->fl.iif ||
557 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
558 score |= (1<<30);
559
560 return score;
561 }
562
563 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
564 {
565 return ((__force u32)((fl1->nl_u.ip4_u.daddr ^ fl2->nl_u.ip4_u.daddr) |
566 (fl1->nl_u.ip4_u.saddr ^ fl2->nl_u.ip4_u.saddr)) |
567 (fl1->mark ^ fl2->mark) |
568 (*(u16 *)&fl1->nl_u.ip4_u.tos ^
569 *(u16 *)&fl2->nl_u.ip4_u.tos) |
570 (fl1->oif ^ fl2->oif) |
571 (fl1->iif ^ fl2->iif)) == 0;
572 }
573
574 /* This runs via a timer and thus is always in BH context. */
575 static void rt_check_expire(unsigned long dummy)
576 {
577 static unsigned int rover;
578 unsigned int i = rover, goal;
579 struct rtable *rth, **rthp;
580 unsigned long now = jiffies;
581 u64 mult;
582
583 mult = ((u64)ip_rt_gc_interval) << rt_hash_log;
584 if (ip_rt_gc_timeout > 1)
585 do_div(mult, ip_rt_gc_timeout);
586 goal = (unsigned int)mult;
587 if (goal > rt_hash_mask) goal = rt_hash_mask + 1;
588 for (; goal > 0; goal--) {
589 unsigned long tmo = ip_rt_gc_timeout;
590
591 i = (i + 1) & rt_hash_mask;
592 rthp = &rt_hash_table[i].chain;
593
594 if (*rthp == 0)
595 continue;
596 spin_lock(rt_hash_lock_addr(i));
597 while ((rth = *rthp) != NULL) {
598 if (rth->u.dst.expires) {
599 /* Entry is expired even if it is in use */
600 if (time_before_eq(now, rth->u.dst.expires)) {
601 tmo >>= 1;
602 rthp = &rth->u.dst.rt_next;
603 continue;
604 }
605 } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
606 tmo >>= 1;
607 rthp = &rth->u.dst.rt_next;
608 continue;
609 }
610
611 /* Cleanup aged off entries. */
612 *rthp = rth->u.dst.rt_next;
613 rt_free(rth);
614 }
615 spin_unlock(rt_hash_lock_addr(i));
616
617 /* Fallback loop breaker. */
618 if (time_after(jiffies, now))
619 break;
620 }
621 rover = i;
622 mod_timer(&rt_periodic_timer, jiffies + ip_rt_gc_interval);
623 }
624
625 /* This can run from both BH and non-BH contexts, the latter
626 * in the case of a forced flush event.
627 */
628 static void rt_run_flush(unsigned long dummy)
629 {
630 int i;
631 struct rtable *rth, *next;
632
633 rt_deadline = 0;
634
635 get_random_bytes(&rt_hash_rnd, 4);
636
637 for (i = rt_hash_mask; i >= 0; i--) {
638 spin_lock_bh(rt_hash_lock_addr(i));
639 rth = rt_hash_table[i].chain;
640 if (rth)
641 rt_hash_table[i].chain = NULL;
642 spin_unlock_bh(rt_hash_lock_addr(i));
643
644 for (; rth; rth = next) {
645 next = rth->u.dst.rt_next;
646 rt_free(rth);
647 }
648 }
649 }
650
651 static DEFINE_SPINLOCK(rt_flush_lock);
652
653 void rt_cache_flush(int delay)
654 {
655 unsigned long now = jiffies;
656 int user_mode = !in_softirq();
657
658 if (delay < 0)
659 delay = ip_rt_min_delay;
660
661 spin_lock_bh(&rt_flush_lock);
662
663 if (del_timer(&rt_flush_timer) && delay > 0 && rt_deadline) {
664 long tmo = (long)(rt_deadline - now);
665
666 /* If flush timer is already running
667 and flush request is not immediate (delay > 0):
668
669 if deadline is not achieved, prolongate timer to "delay",
670 otherwise fire it at deadline time.
671 */
672
673 if (user_mode && tmo < ip_rt_max_delay-ip_rt_min_delay)
674 tmo = 0;
675
676 if (delay > tmo)
677 delay = tmo;
678 }
679
680 if (delay <= 0) {
681 spin_unlock_bh(&rt_flush_lock);
682 rt_run_flush(0);
683 return;
684 }
685
686 if (rt_deadline == 0)
687 rt_deadline = now + ip_rt_max_delay;
688
689 mod_timer(&rt_flush_timer, now+delay);
690 spin_unlock_bh(&rt_flush_lock);
691 }
692
693 static void rt_secret_rebuild(unsigned long dummy)
694 {
695 unsigned long now = jiffies;
696
697 rt_cache_flush(0);
698 mod_timer(&rt_secret_timer, now + ip_rt_secret_interval);
699 }
700
701 /*
702 Short description of GC goals.
703
704 We want to build algorithm, which will keep routing cache
705 at some equilibrium point, when number of aged off entries
706 is kept approximately equal to newly generated ones.
707
708 Current expiration strength is variable "expire".
709 We try to adjust it dynamically, so that if networking
710 is idle expires is large enough to keep enough of warm entries,
711 and when load increases it reduces to limit cache size.
712 */
713
714 static int rt_garbage_collect(void)
715 {
716 static unsigned long expire = RT_GC_TIMEOUT;
717 static unsigned long last_gc;
718 static int rover;
719 static int equilibrium;
720 struct rtable *rth, **rthp;
721 unsigned long now = jiffies;
722 int goal;
723
724 /*
725 * Garbage collection is pretty expensive,
726 * do not make it too frequently.
727 */
728
729 RT_CACHE_STAT_INC(gc_total);
730
731 if (now - last_gc < ip_rt_gc_min_interval &&
732 atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) {
733 RT_CACHE_STAT_INC(gc_ignored);
734 goto out;
735 }
736
737 /* Calculate number of entries, which we want to expire now. */
738 goal = atomic_read(&ipv4_dst_ops.entries) -
739 (ip_rt_gc_elasticity << rt_hash_log);
740 if (goal <= 0) {
741 if (equilibrium < ipv4_dst_ops.gc_thresh)
742 equilibrium = ipv4_dst_ops.gc_thresh;
743 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
744 if (goal > 0) {
745 equilibrium += min_t(unsigned int, goal / 2, rt_hash_mask + 1);
746 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
747 }
748 } else {
749 /* We are in dangerous area. Try to reduce cache really
750 * aggressively.
751 */
752 goal = max_t(unsigned int, goal / 2, rt_hash_mask + 1);
753 equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
754 }
755
756 if (now - last_gc >= ip_rt_gc_min_interval)
757 last_gc = now;
758
759 if (goal <= 0) {
760 equilibrium += goal;
761 goto work_done;
762 }
763
764 do {
765 int i, k;
766
767 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
768 unsigned long tmo = expire;
769
770 k = (k + 1) & rt_hash_mask;
771 rthp = &rt_hash_table[k].chain;
772 spin_lock_bh(rt_hash_lock_addr(k));
773 while ((rth = *rthp) != NULL) {
774 if (!rt_may_expire(rth, tmo, expire)) {
775 tmo >>= 1;
776 rthp = &rth->u.dst.rt_next;
777 continue;
778 }
779 *rthp = rth->u.dst.rt_next;
780 rt_free(rth);
781 goal--;
782 }
783 spin_unlock_bh(rt_hash_lock_addr(k));
784 if (goal <= 0)
785 break;
786 }
787 rover = k;
788
789 if (goal <= 0)
790 goto work_done;
791
792 /* Goal is not achieved. We stop process if:
793
794 - if expire reduced to zero. Otherwise, expire is halfed.
795 - if table is not full.
796 - if we are called from interrupt.
797 - jiffies check is just fallback/debug loop breaker.
798 We will not spin here for long time in any case.
799 */
800
801 RT_CACHE_STAT_INC(gc_goal_miss);
802
803 if (expire == 0)
804 break;
805
806 expire >>= 1;
807 #if RT_CACHE_DEBUG >= 2
808 printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
809 atomic_read(&ipv4_dst_ops.entries), goal, i);
810 #endif
811
812 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
813 goto out;
814 } while (!in_softirq() && time_before_eq(jiffies, now));
815
816 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
817 goto out;
818 if (net_ratelimit())
819 printk(KERN_WARNING "dst cache overflow\n");
820 RT_CACHE_STAT_INC(gc_dst_overflow);
821 return 1;
822
823 work_done:
824 expire += ip_rt_gc_min_interval;
825 if (expire > ip_rt_gc_timeout ||
826 atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh)
827 expire = ip_rt_gc_timeout;
828 #if RT_CACHE_DEBUG >= 2
829 printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
830 atomic_read(&ipv4_dst_ops.entries), goal, rover);
831 #endif
832 out: return 0;
833 }
834
835 static int rt_intern_hash(unsigned hash, struct rtable *rt, struct rtable **rp)
836 {
837 struct rtable *rth, **rthp;
838 unsigned long now;
839 struct rtable *cand, **candp;
840 u32 min_score;
841 int chain_length;
842 int attempts = !in_softirq();
843
844 restart:
845 chain_length = 0;
846 min_score = ~(u32)0;
847 cand = NULL;
848 candp = NULL;
849 now = jiffies;
850
851 rthp = &rt_hash_table[hash].chain;
852
853 spin_lock_bh(rt_hash_lock_addr(hash));
854 while ((rth = *rthp) != NULL) {
855 if (compare_keys(&rth->fl, &rt->fl)) {
856 /* Put it first */
857 *rthp = rth->u.dst.rt_next;
858 /*
859 * Since lookup is lockfree, the deletion
860 * must be visible to another weakly ordered CPU before
861 * the insertion at the start of the hash chain.
862 */
863 rcu_assign_pointer(rth->u.dst.rt_next,
864 rt_hash_table[hash].chain);
865 /*
866 * Since lookup is lockfree, the update writes
867 * must be ordered for consistency on SMP.
868 */
869 rcu_assign_pointer(rt_hash_table[hash].chain, rth);
870
871 rth->u.dst.__use++;
872 dst_hold(&rth->u.dst);
873 rth->u.dst.lastuse = now;
874 spin_unlock_bh(rt_hash_lock_addr(hash));
875
876 rt_drop(rt);
877 *rp = rth;
878 return 0;
879 }
880
881 if (!atomic_read(&rth->u.dst.__refcnt)) {
882 u32 score = rt_score(rth);
883
884 if (score <= min_score) {
885 cand = rth;
886 candp = rthp;
887 min_score = score;
888 }
889 }
890
891 chain_length++;
892
893 rthp = &rth->u.dst.rt_next;
894 }
895
896 if (cand) {
897 /* ip_rt_gc_elasticity used to be average length of chain
898 * length, when exceeded gc becomes really aggressive.
899 *
900 * The second limit is less certain. At the moment it allows
901 * only 2 entries per bucket. We will see.
902 */
903 if (chain_length > ip_rt_gc_elasticity) {
904 *candp = cand->u.dst.rt_next;
905 rt_free(cand);
906 }
907 }
908
909 /* Try to bind route to arp only if it is output
910 route or unicast forwarding path.
911 */
912 if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
913 int err = arp_bind_neighbour(&rt->u.dst);
914 if (err) {
915 spin_unlock_bh(rt_hash_lock_addr(hash));
916
917 if (err != -ENOBUFS) {
918 rt_drop(rt);
919 return err;
920 }
921
922 /* Neighbour tables are full and nothing
923 can be released. Try to shrink route cache,
924 it is most likely it holds some neighbour records.
925 */
926 if (attempts-- > 0) {
927 int saved_elasticity = ip_rt_gc_elasticity;
928 int saved_int = ip_rt_gc_min_interval;
929 ip_rt_gc_elasticity = 1;
930 ip_rt_gc_min_interval = 0;
931 rt_garbage_collect();
932 ip_rt_gc_min_interval = saved_int;
933 ip_rt_gc_elasticity = saved_elasticity;
934 goto restart;
935 }
936
937 if (net_ratelimit())
938 printk(KERN_WARNING "Neighbour table overflow.\n");
939 rt_drop(rt);
940 return -ENOBUFS;
941 }
942 }
943
944 rt->u.dst.rt_next = rt_hash_table[hash].chain;
945 #if RT_CACHE_DEBUG >= 2
946 if (rt->u.dst.rt_next) {
947 struct rtable *trt;
948 printk(KERN_DEBUG "rt_cache @%02x: %u.%u.%u.%u", hash,
949 NIPQUAD(rt->rt_dst));
950 for (trt = rt->u.dst.rt_next; trt; trt = trt->u.dst.rt_next)
951 printk(" . %u.%u.%u.%u", NIPQUAD(trt->rt_dst));
952 printk("\n");
953 }
954 #endif
955 rt_hash_table[hash].chain = rt;
956 spin_unlock_bh(rt_hash_lock_addr(hash));
957 *rp = rt;
958 return 0;
959 }
960
961 void rt_bind_peer(struct rtable *rt, int create)
962 {
963 static DEFINE_SPINLOCK(rt_peer_lock);
964 struct inet_peer *peer;
965
966 peer = inet_getpeer(rt->rt_dst, create);
967
968 spin_lock_bh(&rt_peer_lock);
969 if (rt->peer == NULL) {
970 rt->peer = peer;
971 peer = NULL;
972 }
973 spin_unlock_bh(&rt_peer_lock);
974 if (peer)
975 inet_putpeer(peer);
976 }
977
978 /*
979 * Peer allocation may fail only in serious out-of-memory conditions. However
980 * we still can generate some output.
981 * Random ID selection looks a bit dangerous because we have no chances to
982 * select ID being unique in a reasonable period of time.
983 * But broken packet identifier may be better than no packet at all.
984 */
985 static void ip_select_fb_ident(struct iphdr *iph)
986 {
987 static DEFINE_SPINLOCK(ip_fb_id_lock);
988 static u32 ip_fallback_id;
989 u32 salt;
990
991 spin_lock_bh(&ip_fb_id_lock);
992 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
993 iph->id = htons(salt & 0xFFFF);
994 ip_fallback_id = salt;
995 spin_unlock_bh(&ip_fb_id_lock);
996 }
997
998 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
999 {
1000 struct rtable *rt = (struct rtable *) dst;
1001
1002 if (rt) {
1003 if (rt->peer == NULL)
1004 rt_bind_peer(rt, 1);
1005
1006 /* If peer is attached to destination, it is never detached,
1007 so that we need not to grab a lock to dereference it.
1008 */
1009 if (rt->peer) {
1010 iph->id = htons(inet_getid(rt->peer, more));
1011 return;
1012 }
1013 } else
1014 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1015 __builtin_return_address(0));
1016
1017 ip_select_fb_ident(iph);
1018 }
1019
1020 static void rt_del(unsigned hash, struct rtable *rt)
1021 {
1022 struct rtable **rthp;
1023
1024 spin_lock_bh(rt_hash_lock_addr(hash));
1025 ip_rt_put(rt);
1026 for (rthp = &rt_hash_table[hash].chain; *rthp;
1027 rthp = &(*rthp)->u.dst.rt_next)
1028 if (*rthp == rt) {
1029 *rthp = rt->u.dst.rt_next;
1030 rt_free(rt);
1031 break;
1032 }
1033 spin_unlock_bh(rt_hash_lock_addr(hash));
1034 }
1035
1036 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1037 __be32 saddr, struct net_device *dev)
1038 {
1039 int i, k;
1040 struct in_device *in_dev = in_dev_get(dev);
1041 struct rtable *rth, **rthp;
1042 __be32 skeys[2] = { saddr, 0 };
1043 int ikeys[2] = { dev->ifindex, 0 };
1044 struct netevent_redirect netevent;
1045
1046 if (!in_dev)
1047 return;
1048
1049 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
1050 || MULTICAST(new_gw) || BADCLASS(new_gw) || ZERONET(new_gw))
1051 goto reject_redirect;
1052
1053 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1054 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1055 goto reject_redirect;
1056 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1057 goto reject_redirect;
1058 } else {
1059 if (inet_addr_type(new_gw) != RTN_UNICAST)
1060 goto reject_redirect;
1061 }
1062
1063 for (i = 0; i < 2; i++) {
1064 for (k = 0; k < 2; k++) {
1065 unsigned hash = rt_hash(daddr, skeys[i], ikeys[k]);
1066
1067 rthp=&rt_hash_table[hash].chain;
1068
1069 rcu_read_lock();
1070 while ((rth = rcu_dereference(*rthp)) != NULL) {
1071 struct rtable *rt;
1072
1073 if (rth->fl.fl4_dst != daddr ||
1074 rth->fl.fl4_src != skeys[i] ||
1075 rth->fl.oif != ikeys[k] ||
1076 rth->fl.iif != 0) {
1077 rthp = &rth->u.dst.rt_next;
1078 continue;
1079 }
1080
1081 if (rth->rt_dst != daddr ||
1082 rth->rt_src != saddr ||
1083 rth->u.dst.error ||
1084 rth->rt_gateway != old_gw ||
1085 rth->u.dst.dev != dev)
1086 break;
1087
1088 dst_hold(&rth->u.dst);
1089 rcu_read_unlock();
1090
1091 rt = dst_alloc(&ipv4_dst_ops);
1092 if (rt == NULL) {
1093 ip_rt_put(rth);
1094 in_dev_put(in_dev);
1095 return;
1096 }
1097
1098 /* Copy all the information. */
1099 *rt = *rth;
1100 INIT_RCU_HEAD(&rt->u.dst.rcu_head);
1101 rt->u.dst.__use = 1;
1102 atomic_set(&rt->u.dst.__refcnt, 1);
1103 rt->u.dst.child = NULL;
1104 if (rt->u.dst.dev)
1105 dev_hold(rt->u.dst.dev);
1106 if (rt->idev)
1107 in_dev_hold(rt->idev);
1108 rt->u.dst.obsolete = 0;
1109 rt->u.dst.lastuse = jiffies;
1110 rt->u.dst.path = &rt->u.dst;
1111 rt->u.dst.neighbour = NULL;
1112 rt->u.dst.hh = NULL;
1113 rt->u.dst.xfrm = NULL;
1114
1115 rt->rt_flags |= RTCF_REDIRECTED;
1116
1117 /* Gateway is different ... */
1118 rt->rt_gateway = new_gw;
1119
1120 /* Redirect received -> path was valid */
1121 dst_confirm(&rth->u.dst);
1122
1123 if (rt->peer)
1124 atomic_inc(&rt->peer->refcnt);
1125
1126 if (arp_bind_neighbour(&rt->u.dst) ||
1127 !(rt->u.dst.neighbour->nud_state &
1128 NUD_VALID)) {
1129 if (rt->u.dst.neighbour)
1130 neigh_event_send(rt->u.dst.neighbour, NULL);
1131 ip_rt_put(rth);
1132 rt_drop(rt);
1133 goto do_next;
1134 }
1135
1136 netevent.old = &rth->u.dst;
1137 netevent.new = &rt->u.dst;
1138 call_netevent_notifiers(NETEVENT_REDIRECT,
1139 &netevent);
1140
1141 rt_del(hash, rth);
1142 if (!rt_intern_hash(hash, rt, &rt))
1143 ip_rt_put(rt);
1144 goto do_next;
1145 }
1146 rcu_read_unlock();
1147 do_next:
1148 ;
1149 }
1150 }
1151 in_dev_put(in_dev);
1152 return;
1153
1154 reject_redirect:
1155 #ifdef CONFIG_IP_ROUTE_VERBOSE
1156 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1157 printk(KERN_INFO "Redirect from %u.%u.%u.%u on %s about "
1158 "%u.%u.%u.%u ignored.\n"
1159 " Advised path = %u.%u.%u.%u -> %u.%u.%u.%u\n",
1160 NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw),
1161 NIPQUAD(saddr), NIPQUAD(daddr));
1162 #endif
1163 in_dev_put(in_dev);
1164 }
1165
1166 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1167 {
1168 struct rtable *rt = (struct rtable*)dst;
1169 struct dst_entry *ret = dst;
1170
1171 if (rt) {
1172 if (dst->obsolete) {
1173 ip_rt_put(rt);
1174 ret = NULL;
1175 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
1176 rt->u.dst.expires) {
1177 unsigned hash = rt_hash(rt->fl.fl4_dst, rt->fl.fl4_src,
1178 rt->fl.oif);
1179 #if RT_CACHE_DEBUG >= 1
1180 printk(KERN_DEBUG "ip_rt_advice: redirect to "
1181 "%u.%u.%u.%u/%02x dropped\n",
1182 NIPQUAD(rt->rt_dst), rt->fl.fl4_tos);
1183 #endif
1184 rt_del(hash, rt);
1185 ret = NULL;
1186 }
1187 }
1188 return ret;
1189 }
1190
1191 /*
1192 * Algorithm:
1193 * 1. The first ip_rt_redirect_number redirects are sent
1194 * with exponential backoff, then we stop sending them at all,
1195 * assuming that the host ignores our redirects.
1196 * 2. If we did not see packets requiring redirects
1197 * during ip_rt_redirect_silence, we assume that the host
1198 * forgot redirected route and start to send redirects again.
1199 *
1200 * This algorithm is much cheaper and more intelligent than dumb load limiting
1201 * in icmp.c.
1202 *
1203 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1204 * and "frag. need" (breaks PMTU discovery) in icmp.c.
1205 */
1206
1207 void ip_rt_send_redirect(struct sk_buff *skb)
1208 {
1209 struct rtable *rt = (struct rtable*)skb->dst;
1210 struct in_device *in_dev = in_dev_get(rt->u.dst.dev);
1211
1212 if (!in_dev)
1213 return;
1214
1215 if (!IN_DEV_TX_REDIRECTS(in_dev))
1216 goto out;
1217
1218 /* No redirected packets during ip_rt_redirect_silence;
1219 * reset the algorithm.
1220 */
1221 if (time_after(jiffies, rt->u.dst.rate_last + ip_rt_redirect_silence))
1222 rt->u.dst.rate_tokens = 0;
1223
1224 /* Too many ignored redirects; do not send anything
1225 * set u.dst.rate_last to the last seen redirected packet.
1226 */
1227 if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) {
1228 rt->u.dst.rate_last = jiffies;
1229 goto out;
1230 }
1231
1232 /* Check for load limit; set rate_last to the latest sent
1233 * redirect.
1234 */
1235 if (rt->u.dst.rate_tokens == 0 ||
1236 time_after(jiffies,
1237 (rt->u.dst.rate_last +
1238 (ip_rt_redirect_load << rt->u.dst.rate_tokens)))) {
1239 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1240 rt->u.dst.rate_last = jiffies;
1241 ++rt->u.dst.rate_tokens;
1242 #ifdef CONFIG_IP_ROUTE_VERBOSE
1243 if (IN_DEV_LOG_MARTIANS(in_dev) &&
1244 rt->u.dst.rate_tokens == ip_rt_redirect_number &&
1245 net_ratelimit())
1246 printk(KERN_WARNING "host %u.%u.%u.%u/if%d ignores "
1247 "redirects for %u.%u.%u.%u to %u.%u.%u.%u.\n",
1248 NIPQUAD(rt->rt_src), rt->rt_iif,
1249 NIPQUAD(rt->rt_dst), NIPQUAD(rt->rt_gateway));
1250 #endif
1251 }
1252 out:
1253 in_dev_put(in_dev);
1254 }
1255
1256 static int ip_error(struct sk_buff *skb)
1257 {
1258 struct rtable *rt = (struct rtable*)skb->dst;
1259 unsigned long now;
1260 int code;
1261
1262 switch (rt->u.dst.error) {
1263 case EINVAL:
1264 default:
1265 goto out;
1266 case EHOSTUNREACH:
1267 code = ICMP_HOST_UNREACH;
1268 break;
1269 case ENETUNREACH:
1270 code = ICMP_NET_UNREACH;
1271 break;
1272 case EACCES:
1273 code = ICMP_PKT_FILTERED;
1274 break;
1275 }
1276
1277 now = jiffies;
1278 rt->u.dst.rate_tokens += now - rt->u.dst.rate_last;
1279 if (rt->u.dst.rate_tokens > ip_rt_error_burst)
1280 rt->u.dst.rate_tokens = ip_rt_error_burst;
1281 rt->u.dst.rate_last = now;
1282 if (rt->u.dst.rate_tokens >= ip_rt_error_cost) {
1283 rt->u.dst.rate_tokens -= ip_rt_error_cost;
1284 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1285 }
1286
1287 out: kfree_skb(skb);
1288 return 0;
1289 }
1290
1291 /*
1292 * The last two values are not from the RFC but
1293 * are needed for AMPRnet AX.25 paths.
1294 */
1295
1296 static const unsigned short mtu_plateau[] =
1297 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1298
1299 static __inline__ unsigned short guess_mtu(unsigned short old_mtu)
1300 {
1301 int i;
1302
1303 for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1304 if (old_mtu > mtu_plateau[i])
1305 return mtu_plateau[i];
1306 return 68;
1307 }
1308
1309 unsigned short ip_rt_frag_needed(struct iphdr *iph, unsigned short new_mtu)
1310 {
1311 int i;
1312 unsigned short old_mtu = ntohs(iph->tot_len);
1313 struct rtable *rth;
1314 __be32 skeys[2] = { iph->saddr, 0, };
1315 __be32 daddr = iph->daddr;
1316 unsigned short est_mtu = 0;
1317
1318 if (ipv4_config.no_pmtu_disc)
1319 return 0;
1320
1321 for (i = 0; i < 2; i++) {
1322 unsigned hash = rt_hash(daddr, skeys[i], 0);
1323
1324 rcu_read_lock();
1325 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
1326 rth = rcu_dereference(rth->u.dst.rt_next)) {
1327 if (rth->fl.fl4_dst == daddr &&
1328 rth->fl.fl4_src == skeys[i] &&
1329 rth->rt_dst == daddr &&
1330 rth->rt_src == iph->saddr &&
1331 rth->fl.iif == 0 &&
1332 !(dst_metric_locked(&rth->u.dst, RTAX_MTU))) {
1333 unsigned short mtu = new_mtu;
1334
1335 if (new_mtu < 68 || new_mtu >= old_mtu) {
1336
1337 /* BSD 4.2 compatibility hack :-( */
1338 if (mtu == 0 &&
1339 old_mtu >= rth->u.dst.metrics[RTAX_MTU-1] &&
1340 old_mtu >= 68 + (iph->ihl << 2))
1341 old_mtu -= iph->ihl << 2;
1342
1343 mtu = guess_mtu(old_mtu);
1344 }
1345 if (mtu <= rth->u.dst.metrics[RTAX_MTU-1]) {
1346 if (mtu < rth->u.dst.metrics[RTAX_MTU-1]) {
1347 dst_confirm(&rth->u.dst);
1348 if (mtu < ip_rt_min_pmtu) {
1349 mtu = ip_rt_min_pmtu;
1350 rth->u.dst.metrics[RTAX_LOCK-1] |=
1351 (1 << RTAX_MTU);
1352 }
1353 rth->u.dst.metrics[RTAX_MTU-1] = mtu;
1354 dst_set_expires(&rth->u.dst,
1355 ip_rt_mtu_expires);
1356 }
1357 est_mtu = mtu;
1358 }
1359 }
1360 }
1361 rcu_read_unlock();
1362 }
1363 return est_mtu ? : new_mtu;
1364 }
1365
1366 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1367 {
1368 if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= 68 &&
1369 !(dst_metric_locked(dst, RTAX_MTU))) {
1370 if (mtu < ip_rt_min_pmtu) {
1371 mtu = ip_rt_min_pmtu;
1372 dst->metrics[RTAX_LOCK-1] |= (1 << RTAX_MTU);
1373 }
1374 dst->metrics[RTAX_MTU-1] = mtu;
1375 dst_set_expires(dst, ip_rt_mtu_expires);
1376 call_netevent_notifiers(NETEVENT_PMTU_UPDATE, dst);
1377 }
1378 }
1379
1380 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1381 {
1382 return NULL;
1383 }
1384
1385 static void ipv4_dst_destroy(struct dst_entry *dst)
1386 {
1387 struct rtable *rt = (struct rtable *) dst;
1388 struct inet_peer *peer = rt->peer;
1389 struct in_device *idev = rt->idev;
1390
1391 if (peer) {
1392 rt->peer = NULL;
1393 inet_putpeer(peer);
1394 }
1395
1396 if (idev) {
1397 rt->idev = NULL;
1398 in_dev_put(idev);
1399 }
1400 }
1401
1402 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
1403 int how)
1404 {
1405 struct rtable *rt = (struct rtable *) dst;
1406 struct in_device *idev = rt->idev;
1407 if (dev != &loopback_dev && idev && idev->dev == dev) {
1408 struct in_device *loopback_idev = in_dev_get(&loopback_dev);
1409 if (loopback_idev) {
1410 rt->idev = loopback_idev;
1411 in_dev_put(idev);
1412 }
1413 }
1414 }
1415
1416 static void ipv4_link_failure(struct sk_buff *skb)
1417 {
1418 struct rtable *rt;
1419
1420 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1421
1422 rt = (struct rtable *) skb->dst;
1423 if (rt)
1424 dst_set_expires(&rt->u.dst, 0);
1425 }
1426
1427 static int ip_rt_bug(struct sk_buff *skb)
1428 {
1429 printk(KERN_DEBUG "ip_rt_bug: %u.%u.%u.%u -> %u.%u.%u.%u, %s\n",
1430 NIPQUAD(ip_hdr(skb)->saddr), NIPQUAD(ip_hdr(skb)->daddr),
1431 skb->dev ? skb->dev->name : "?");
1432 kfree_skb(skb);
1433 return 0;
1434 }
1435
1436 /*
1437 We do not cache source address of outgoing interface,
1438 because it is used only by IP RR, TS and SRR options,
1439 so that it out of fast path.
1440
1441 BTW remember: "addr" is allowed to be not aligned
1442 in IP options!
1443 */
1444
1445 void ip_rt_get_source(u8 *addr, struct rtable *rt)
1446 {
1447 __be32 src;
1448 struct fib_result res;
1449
1450 if (rt->fl.iif == 0)
1451 src = rt->rt_src;
1452 else if (fib_lookup(&rt->fl, &res) == 0) {
1453 src = FIB_RES_PREFSRC(res);
1454 fib_res_put(&res);
1455 } else
1456 src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway,
1457 RT_SCOPE_UNIVERSE);
1458 memcpy(addr, &src, 4);
1459 }
1460
1461 #ifdef CONFIG_NET_CLS_ROUTE
1462 static void set_class_tag(struct rtable *rt, u32 tag)
1463 {
1464 if (!(rt->u.dst.tclassid & 0xFFFF))
1465 rt->u.dst.tclassid |= tag & 0xFFFF;
1466 if (!(rt->u.dst.tclassid & 0xFFFF0000))
1467 rt->u.dst.tclassid |= tag & 0xFFFF0000;
1468 }
1469 #endif
1470
1471 static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
1472 {
1473 struct fib_info *fi = res->fi;
1474
1475 if (fi) {
1476 if (FIB_RES_GW(*res) &&
1477 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1478 rt->rt_gateway = FIB_RES_GW(*res);
1479 memcpy(rt->u.dst.metrics, fi->fib_metrics,
1480 sizeof(rt->u.dst.metrics));
1481 if (fi->fib_mtu == 0) {
1482 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
1483 if (rt->u.dst.metrics[RTAX_LOCK-1] & (1 << RTAX_MTU) &&
1484 rt->rt_gateway != rt->rt_dst &&
1485 rt->u.dst.dev->mtu > 576)
1486 rt->u.dst.metrics[RTAX_MTU-1] = 576;
1487 }
1488 #ifdef CONFIG_NET_CLS_ROUTE
1489 rt->u.dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1490 #endif
1491 } else
1492 rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu;
1493
1494 if (rt->u.dst.metrics[RTAX_HOPLIMIT-1] == 0)
1495 rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl;
1496 if (rt->u.dst.metrics[RTAX_MTU-1] > IP_MAX_MTU)
1497 rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU;
1498 if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0)
1499 rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40,
1500 ip_rt_min_advmss);
1501 if (rt->u.dst.metrics[RTAX_ADVMSS-1] > 65535 - 40)
1502 rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40;
1503
1504 #ifdef CONFIG_NET_CLS_ROUTE
1505 #ifdef CONFIG_IP_MULTIPLE_TABLES
1506 set_class_tag(rt, fib_rules_tclass(res));
1507 #endif
1508 set_class_tag(rt, itag);
1509 #endif
1510 rt->rt_type = res->type;
1511 }
1512
1513 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1514 u8 tos, struct net_device *dev, int our)
1515 {
1516 unsigned hash;
1517 struct rtable *rth;
1518 __be32 spec_dst;
1519 struct in_device *in_dev = in_dev_get(dev);
1520 u32 itag = 0;
1521
1522 /* Primary sanity checks. */
1523
1524 if (in_dev == NULL)
1525 return -EINVAL;
1526
1527 if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr) ||
1528 skb->protocol != htons(ETH_P_IP))
1529 goto e_inval;
1530
1531 if (ZERONET(saddr)) {
1532 if (!LOCAL_MCAST(daddr))
1533 goto e_inval;
1534 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1535 } else if (fib_validate_source(saddr, 0, tos, 0,
1536 dev, &spec_dst, &itag) < 0)
1537 goto e_inval;
1538
1539 rth = dst_alloc(&ipv4_dst_ops);
1540 if (!rth)
1541 goto e_nobufs;
1542
1543 rth->u.dst.output= ip_rt_bug;
1544
1545 atomic_set(&rth->u.dst.__refcnt, 1);
1546 rth->u.dst.flags= DST_HOST;
1547 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
1548 rth->u.dst.flags |= DST_NOPOLICY;
1549 rth->fl.fl4_dst = daddr;
1550 rth->rt_dst = daddr;
1551 rth->fl.fl4_tos = tos;
1552 rth->fl.mark = skb->mark;
1553 rth->fl.fl4_src = saddr;
1554 rth->rt_src = saddr;
1555 #ifdef CONFIG_NET_CLS_ROUTE
1556 rth->u.dst.tclassid = itag;
1557 #endif
1558 rth->rt_iif =
1559 rth->fl.iif = dev->ifindex;
1560 rth->u.dst.dev = &loopback_dev;
1561 dev_hold(rth->u.dst.dev);
1562 rth->idev = in_dev_get(rth->u.dst.dev);
1563 rth->fl.oif = 0;
1564 rth->rt_gateway = daddr;
1565 rth->rt_spec_dst= spec_dst;
1566 rth->rt_type = RTN_MULTICAST;
1567 rth->rt_flags = RTCF_MULTICAST;
1568 if (our) {
1569 rth->u.dst.input= ip_local_deliver;
1570 rth->rt_flags |= RTCF_LOCAL;
1571 }
1572
1573 #ifdef CONFIG_IP_MROUTE
1574 if (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev))
1575 rth->u.dst.input = ip_mr_input;
1576 #endif
1577 RT_CACHE_STAT_INC(in_slow_mc);
1578
1579 in_dev_put(in_dev);
1580 hash = rt_hash(daddr, saddr, dev->ifindex);
1581 return rt_intern_hash(hash, rth, (struct rtable**) &skb->dst);
1582
1583 e_nobufs:
1584 in_dev_put(in_dev);
1585 return -ENOBUFS;
1586
1587 e_inval:
1588 in_dev_put(in_dev);
1589 return -EINVAL;
1590 }
1591
1592
1593 static void ip_handle_martian_source(struct net_device *dev,
1594 struct in_device *in_dev,
1595 struct sk_buff *skb,
1596 __be32 daddr,
1597 __be32 saddr)
1598 {
1599 RT_CACHE_STAT_INC(in_martian_src);
1600 #ifdef CONFIG_IP_ROUTE_VERBOSE
1601 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1602 /*
1603 * RFC1812 recommendation, if source is martian,
1604 * the only hint is MAC header.
1605 */
1606 printk(KERN_WARNING "martian source %u.%u.%u.%u from "
1607 "%u.%u.%u.%u, on dev %s\n",
1608 NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
1609 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1610 int i;
1611 const unsigned char *p = skb_mac_header(skb);
1612 printk(KERN_WARNING "ll header: ");
1613 for (i = 0; i < dev->hard_header_len; i++, p++) {
1614 printk("%02x", *p);
1615 if (i < (dev->hard_header_len - 1))
1616 printk(":");
1617 }
1618 printk("\n");
1619 }
1620 }
1621 #endif
1622 }
1623
1624 static inline int __mkroute_input(struct sk_buff *skb,
1625 struct fib_result* res,
1626 struct in_device *in_dev,
1627 __be32 daddr, __be32 saddr, u32 tos,
1628 struct rtable **result)
1629 {
1630
1631 struct rtable *rth;
1632 int err;
1633 struct in_device *out_dev;
1634 unsigned flags = 0;
1635 __be32 spec_dst;
1636 u32 itag;
1637
1638 /* get a working reference to the output device */
1639 out_dev = in_dev_get(FIB_RES_DEV(*res));
1640 if (out_dev == NULL) {
1641 if (net_ratelimit())
1642 printk(KERN_CRIT "Bug in ip_route_input" \
1643 "_slow(). Please, report\n");
1644 return -EINVAL;
1645 }
1646
1647
1648 err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
1649 in_dev->dev, &spec_dst, &itag);
1650 if (err < 0) {
1651 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1652 saddr);
1653
1654 err = -EINVAL;
1655 goto cleanup;
1656 }
1657
1658 if (err)
1659 flags |= RTCF_DIRECTSRC;
1660
1661 if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) &&
1662 (IN_DEV_SHARED_MEDIA(out_dev) ||
1663 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1664 flags |= RTCF_DOREDIRECT;
1665
1666 if (skb->protocol != htons(ETH_P_IP)) {
1667 /* Not IP (i.e. ARP). Do not create route, if it is
1668 * invalid for proxy arp. DNAT routes are always valid.
1669 */
1670 if (out_dev == in_dev && !(flags & RTCF_DNAT)) {
1671 err = -EINVAL;
1672 goto cleanup;
1673 }
1674 }
1675
1676
1677 rth = dst_alloc(&ipv4_dst_ops);
1678 if (!rth) {
1679 err = -ENOBUFS;
1680 goto cleanup;
1681 }
1682
1683 atomic_set(&rth->u.dst.__refcnt, 1);
1684 rth->u.dst.flags= DST_HOST;
1685 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
1686 rth->u.dst.flags |= DST_NOPOLICY;
1687 if (IN_DEV_CONF_GET(out_dev, NOXFRM))
1688 rth->u.dst.flags |= DST_NOXFRM;
1689 rth->fl.fl4_dst = daddr;
1690 rth->rt_dst = daddr;
1691 rth->fl.fl4_tos = tos;
1692 rth->fl.mark = skb->mark;
1693 rth->fl.fl4_src = saddr;
1694 rth->rt_src = saddr;
1695 rth->rt_gateway = daddr;
1696 rth->rt_iif =
1697 rth->fl.iif = in_dev->dev->ifindex;
1698 rth->u.dst.dev = (out_dev)->dev;
1699 dev_hold(rth->u.dst.dev);
1700 rth->idev = in_dev_get(rth->u.dst.dev);
1701 rth->fl.oif = 0;
1702 rth->rt_spec_dst= spec_dst;
1703
1704 rth->u.dst.input = ip_forward;
1705 rth->u.dst.output = ip_output;
1706
1707 rt_set_nexthop(rth, res, itag);
1708
1709 rth->rt_flags = flags;
1710
1711 *result = rth;
1712 err = 0;
1713 cleanup:
1714 /* release the working reference to the output device */
1715 in_dev_put(out_dev);
1716 return err;
1717 }
1718
1719 static inline int ip_mkroute_input(struct sk_buff *skb,
1720 struct fib_result* res,
1721 const struct flowi *fl,
1722 struct in_device *in_dev,
1723 __be32 daddr, __be32 saddr, u32 tos)
1724 {
1725 struct rtable* rth = NULL;
1726 int err;
1727 unsigned hash;
1728
1729 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1730 if (res->fi && res->fi->fib_nhs > 1 && fl->oif == 0)
1731 fib_select_multipath(fl, res);
1732 #endif
1733
1734 /* create a routing cache entry */
1735 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1736 if (err)
1737 return err;
1738
1739 /* put it into the cache */
1740 hash = rt_hash(daddr, saddr, fl->iif);
1741 return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
1742 }
1743
1744 /*
1745 * NOTE. We drop all the packets that has local source
1746 * addresses, because every properly looped back packet
1747 * must have correct destination already attached by output routine.
1748 *
1749 * Such approach solves two big problems:
1750 * 1. Not simplex devices are handled properly.
1751 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1752 */
1753
1754 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1755 u8 tos, struct net_device *dev)
1756 {
1757 struct fib_result res;
1758 struct in_device *in_dev = in_dev_get(dev);
1759 struct flowi fl = { .nl_u = { .ip4_u =
1760 { .daddr = daddr,
1761 .saddr = saddr,
1762 .tos = tos,
1763 .scope = RT_SCOPE_UNIVERSE,
1764 } },
1765 .mark = skb->mark,
1766 .iif = dev->ifindex };
1767 unsigned flags = 0;
1768 u32 itag = 0;
1769 struct rtable * rth;
1770 unsigned hash;
1771 __be32 spec_dst;
1772 int err = -EINVAL;
1773 int free_res = 0;
1774
1775 /* IP on this device is disabled. */
1776
1777 if (!in_dev)
1778 goto out;
1779
1780 /* Check for the most weird martians, which can be not detected
1781 by fib_lookup.
1782 */
1783
1784 if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr))
1785 goto martian_source;
1786
1787 if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
1788 goto brd_input;
1789
1790 /* Accept zero addresses only to limited broadcast;
1791 * I even do not know to fix it or not. Waiting for complains :-)
1792 */
1793 if (ZERONET(saddr))
1794 goto martian_source;
1795
1796 if (BADCLASS(daddr) || ZERONET(daddr) || LOOPBACK(daddr))
1797 goto martian_destination;
1798
1799 /*
1800 * Now we are ready to route packet.
1801 */
1802 if ((err = fib_lookup(&fl, &res)) != 0) {
1803 if (!IN_DEV_FORWARD(in_dev))
1804 goto e_hostunreach;
1805 goto no_route;
1806 }
1807 free_res = 1;
1808
1809 RT_CACHE_STAT_INC(in_slow_tot);
1810
1811 if (res.type == RTN_BROADCAST)
1812 goto brd_input;
1813
1814 if (res.type == RTN_LOCAL) {
1815 int result;
1816 result = fib_validate_source(saddr, daddr, tos,
1817 loopback_dev.ifindex,
1818 dev, &spec_dst, &itag);
1819 if (result < 0)
1820 goto martian_source;
1821 if (result)
1822 flags |= RTCF_DIRECTSRC;
1823 spec_dst = daddr;
1824 goto local_input;
1825 }
1826
1827 if (!IN_DEV_FORWARD(in_dev))
1828 goto e_hostunreach;
1829 if (res.type != RTN_UNICAST)
1830 goto martian_destination;
1831
1832 err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
1833 if (err == -ENOBUFS)
1834 goto e_nobufs;
1835 if (err == -EINVAL)
1836 goto e_inval;
1837
1838 done:
1839 in_dev_put(in_dev);
1840 if (free_res)
1841 fib_res_put(&res);
1842 out: return err;
1843
1844 brd_input:
1845 if (skb->protocol != htons(ETH_P_IP))
1846 goto e_inval;
1847
1848 if (ZERONET(saddr))
1849 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1850 else {
1851 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
1852 &itag);
1853 if (err < 0)
1854 goto martian_source;
1855 if (err)
1856 flags |= RTCF_DIRECTSRC;
1857 }
1858 flags |= RTCF_BROADCAST;
1859 res.type = RTN_BROADCAST;
1860 RT_CACHE_STAT_INC(in_brd);
1861
1862 local_input:
1863 rth = dst_alloc(&ipv4_dst_ops);
1864 if (!rth)
1865 goto e_nobufs;
1866
1867 rth->u.dst.output= ip_rt_bug;
1868
1869 atomic_set(&rth->u.dst.__refcnt, 1);
1870 rth->u.dst.flags= DST_HOST;
1871 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
1872 rth->u.dst.flags |= DST_NOPOLICY;
1873 rth->fl.fl4_dst = daddr;
1874 rth->rt_dst = daddr;
1875 rth->fl.fl4_tos = tos;
1876 rth->fl.mark = skb->mark;
1877 rth->fl.fl4_src = saddr;
1878 rth->rt_src = saddr;
1879 #ifdef CONFIG_NET_CLS_ROUTE
1880 rth->u.dst.tclassid = itag;
1881 #endif
1882 rth->rt_iif =
1883 rth->fl.iif = dev->ifindex;
1884 rth->u.dst.dev = &loopback_dev;
1885 dev_hold(rth->u.dst.dev);
1886 rth->idev = in_dev_get(rth->u.dst.dev);
1887 rth->rt_gateway = daddr;
1888 rth->rt_spec_dst= spec_dst;
1889 rth->u.dst.input= ip_local_deliver;
1890 rth->rt_flags = flags|RTCF_LOCAL;
1891 if (res.type == RTN_UNREACHABLE) {
1892 rth->u.dst.input= ip_error;
1893 rth->u.dst.error= -err;
1894 rth->rt_flags &= ~RTCF_LOCAL;
1895 }
1896 rth->rt_type = res.type;
1897 hash = rt_hash(daddr, saddr, fl.iif);
1898 err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
1899 goto done;
1900
1901 no_route:
1902 RT_CACHE_STAT_INC(in_no_route);
1903 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
1904 res.type = RTN_UNREACHABLE;
1905 goto local_input;
1906
1907 /*
1908 * Do not cache martian addresses: they should be logged (RFC1812)
1909 */
1910 martian_destination:
1911 RT_CACHE_STAT_INC(in_martian_dst);
1912 #ifdef CONFIG_IP_ROUTE_VERBOSE
1913 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1914 printk(KERN_WARNING "martian destination %u.%u.%u.%u from "
1915 "%u.%u.%u.%u, dev %s\n",
1916 NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
1917 #endif
1918
1919 e_hostunreach:
1920 err = -EHOSTUNREACH;
1921 goto done;
1922
1923 e_inval:
1924 err = -EINVAL;
1925 goto done;
1926
1927 e_nobufs:
1928 err = -ENOBUFS;
1929 goto done;
1930
1931 martian_source:
1932 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1933 goto e_inval;
1934 }
1935
1936 int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1937 u8 tos, struct net_device *dev)
1938 {
1939 struct rtable * rth;
1940 unsigned hash;
1941 int iif = dev->ifindex;
1942
1943 tos &= IPTOS_RT_MASK;
1944 hash = rt_hash(daddr, saddr, iif);
1945
1946 rcu_read_lock();
1947 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
1948 rth = rcu_dereference(rth->u.dst.rt_next)) {
1949 if (rth->fl.fl4_dst == daddr &&
1950 rth->fl.fl4_src == saddr &&
1951 rth->fl.iif == iif &&
1952 rth->fl.oif == 0 &&
1953 rth->fl.mark == skb->mark &&
1954 rth->fl.fl4_tos == tos) {
1955 rth->u.dst.lastuse = jiffies;
1956 dst_hold(&rth->u.dst);
1957 rth->u.dst.__use++;
1958 RT_CACHE_STAT_INC(in_hit);
1959 rcu_read_unlock();
1960 skb->dst = (struct dst_entry*)rth;
1961 return 0;
1962 }
1963 RT_CACHE_STAT_INC(in_hlist_search);
1964 }
1965 rcu_read_unlock();
1966
1967 /* Multicast recognition logic is moved from route cache to here.
1968 The problem was that too many Ethernet cards have broken/missing
1969 hardware multicast filters :-( As result the host on multicasting
1970 network acquires a lot of useless route cache entries, sort of
1971 SDR messages from all the world. Now we try to get rid of them.
1972 Really, provided software IP multicast filter is organized
1973 reasonably (at least, hashed), it does not result in a slowdown
1974 comparing with route cache reject entries.
1975 Note, that multicast routers are not affected, because
1976 route cache entry is created eventually.
1977 */
1978 if (MULTICAST(daddr)) {
1979 struct in_device *in_dev;
1980
1981 rcu_read_lock();
1982 if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
1983 int our = ip_check_mc(in_dev, daddr, saddr,
1984 ip_hdr(skb)->protocol);
1985 if (our
1986 #ifdef CONFIG_IP_MROUTE
1987 || (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev))
1988 #endif
1989 ) {
1990 rcu_read_unlock();
1991 return ip_route_input_mc(skb, daddr, saddr,
1992 tos, dev, our);
1993 }
1994 }
1995 rcu_read_unlock();
1996 return -EINVAL;
1997 }
1998 return ip_route_input_slow(skb, daddr, saddr, tos, dev);
1999 }
2000
2001 static inline int __mkroute_output(struct rtable **result,
2002 struct fib_result* res,
2003 const struct flowi *fl,
2004 const struct flowi *oldflp,
2005 struct net_device *dev_out,
2006 unsigned flags)
2007 {
2008 struct rtable *rth;
2009 struct in_device *in_dev;
2010 u32 tos = RT_FL_TOS(oldflp);
2011 int err = 0;
2012
2013 if (LOOPBACK(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
2014 return -EINVAL;
2015
2016 if (fl->fl4_dst == htonl(0xFFFFFFFF))
2017 res->type = RTN_BROADCAST;
2018 else if (MULTICAST(fl->fl4_dst))
2019 res->type = RTN_MULTICAST;
2020 else if (BADCLASS(fl->fl4_dst) || ZERONET(fl->fl4_dst))
2021 return -EINVAL;
2022
2023 if (dev_out->flags & IFF_LOOPBACK)
2024 flags |= RTCF_LOCAL;
2025
2026 /* get work reference to inet device */
2027 in_dev = in_dev_get(dev_out);
2028 if (!in_dev)
2029 return -EINVAL;
2030
2031 if (res->type == RTN_BROADCAST) {
2032 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2033 if (res->fi) {
2034 fib_info_put(res->fi);
2035 res->fi = NULL;
2036 }
2037 } else if (res->type == RTN_MULTICAST) {
2038 flags |= RTCF_MULTICAST|RTCF_LOCAL;
2039 if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
2040 oldflp->proto))
2041 flags &= ~RTCF_LOCAL;
2042 /* If multicast route do not exist use
2043 default one, but do not gateway in this case.
2044 Yes, it is hack.
2045 */
2046 if (res->fi && res->prefixlen < 4) {
2047 fib_info_put(res->fi);
2048 res->fi = NULL;
2049 }
2050 }
2051
2052
2053 rth = dst_alloc(&ipv4_dst_ops);
2054 if (!rth) {
2055 err = -ENOBUFS;
2056 goto cleanup;
2057 }
2058
2059 atomic_set(&rth->u.dst.__refcnt, 1);
2060 rth->u.dst.flags= DST_HOST;
2061 if (IN_DEV_CONF_GET(in_dev, NOXFRM))
2062 rth->u.dst.flags |= DST_NOXFRM;
2063 if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
2064 rth->u.dst.flags |= DST_NOPOLICY;
2065
2066 rth->fl.fl4_dst = oldflp->fl4_dst;
2067 rth->fl.fl4_tos = tos;
2068 rth->fl.fl4_src = oldflp->fl4_src;
2069 rth->fl.oif = oldflp->oif;
2070 rth->fl.mark = oldflp->mark;
2071 rth->rt_dst = fl->fl4_dst;
2072 rth->rt_src = fl->fl4_src;
2073 rth->rt_iif = oldflp->oif ? : dev_out->ifindex;
2074 /* get references to the devices that are to be hold by the routing
2075 cache entry */
2076 rth->u.dst.dev = dev_out;
2077 dev_hold(dev_out);
2078 rth->idev = in_dev_get(dev_out);
2079 rth->rt_gateway = fl->fl4_dst;
2080 rth->rt_spec_dst= fl->fl4_src;
2081
2082 rth->u.dst.output=ip_output;
2083
2084 RT_CACHE_STAT_INC(out_slow_tot);
2085
2086 if (flags & RTCF_LOCAL) {
2087 rth->u.dst.input = ip_local_deliver;
2088 rth->rt_spec_dst = fl->fl4_dst;
2089 }
2090 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2091 rth->rt_spec_dst = fl->fl4_src;
2092 if (flags & RTCF_LOCAL &&
2093 !(dev_out->flags & IFF_LOOPBACK)) {
2094 rth->u.dst.output = ip_mc_output;
2095 RT_CACHE_STAT_INC(out_slow_mc);
2096 }
2097 #ifdef CONFIG_IP_MROUTE
2098 if (res->type == RTN_MULTICAST) {
2099 if (IN_DEV_MFORWARD(in_dev) &&
2100 !LOCAL_MCAST(oldflp->fl4_dst)) {
2101 rth->u.dst.input = ip_mr_input;
2102 rth->u.dst.output = ip_mc_output;
2103 }
2104 }
2105 #endif
2106 }
2107
2108 rt_set_nexthop(rth, res, 0);
2109
2110 rth->rt_flags = flags;
2111
2112 *result = rth;
2113 cleanup:
2114 /* release work reference to inet device */
2115 in_dev_put(in_dev);
2116
2117 return err;
2118 }
2119
2120 static inline int ip_mkroute_output(struct rtable **rp,
2121 struct fib_result* res,
2122 const struct flowi *fl,
2123 const struct flowi *oldflp,
2124 struct net_device *dev_out,
2125 unsigned flags)
2126 {
2127 struct rtable *rth = NULL;
2128 int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
2129 unsigned hash;
2130 if (err == 0) {
2131 hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif);
2132 err = rt_intern_hash(hash, rth, rp);
2133 }
2134
2135 return err;
2136 }
2137
2138 /*
2139 * Major route resolver routine.
2140 */
2141
2142 static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
2143 {
2144 u32 tos = RT_FL_TOS(oldflp);
2145 struct flowi fl = { .nl_u = { .ip4_u =
2146 { .daddr = oldflp->fl4_dst,
2147 .saddr = oldflp->fl4_src,
2148 .tos = tos & IPTOS_RT_MASK,
2149 .scope = ((tos & RTO_ONLINK) ?
2150 RT_SCOPE_LINK :
2151 RT_SCOPE_UNIVERSE),
2152 } },
2153 .mark = oldflp->mark,
2154 .iif = loopback_dev.ifindex,
2155 .oif = oldflp->oif };
2156 struct fib_result res;
2157 unsigned flags = 0;
2158 struct net_device *dev_out = NULL;
2159 int free_res = 0;
2160 int err;
2161
2162
2163 res.fi = NULL;
2164 #ifdef CONFIG_IP_MULTIPLE_TABLES
2165 res.r = NULL;
2166 #endif
2167
2168 if (oldflp->fl4_src) {
2169 err = -EINVAL;
2170 if (MULTICAST(oldflp->fl4_src) ||
2171 BADCLASS(oldflp->fl4_src) ||
2172 ZERONET(oldflp->fl4_src))
2173 goto out;
2174
2175 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2176 dev_out = ip_dev_find(oldflp->fl4_src);
2177 if (dev_out == NULL)
2178 goto out;
2179
2180 /* I removed check for oif == dev_out->oif here.
2181 It was wrong for two reasons:
2182 1. ip_dev_find(saddr) can return wrong iface, if saddr is
2183 assigned to multiple interfaces.
2184 2. Moreover, we are allowed to send packets with saddr
2185 of another iface. --ANK
2186 */
2187
2188 if (oldflp->oif == 0
2189 && (MULTICAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
2190 /* Special hack: user can direct multicasts
2191 and limited broadcast via necessary interface
2192 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2193 This hack is not just for fun, it allows
2194 vic,vat and friends to work.
2195 They bind socket to loopback, set ttl to zero
2196 and expect that it will work.
2197 From the viewpoint of routing cache they are broken,
2198 because we are not allowed to build multicast path
2199 with loopback source addr (look, routing cache
2200 cannot know, that ttl is zero, so that packet
2201 will not leave this host and route is valid).
2202 Luckily, this hack is good workaround.
2203 */
2204
2205 fl.oif = dev_out->ifindex;
2206 goto make_route;
2207 }
2208 if (dev_out)
2209 dev_put(dev_out);
2210 dev_out = NULL;
2211 }
2212
2213
2214 if (oldflp->oif) {
2215 dev_out = dev_get_by_index(oldflp->oif);
2216 err = -ENODEV;
2217 if (dev_out == NULL)
2218 goto out;
2219
2220 /* RACE: Check return value of inet_select_addr instead. */
2221 if (__in_dev_get_rtnl(dev_out) == NULL) {
2222 dev_put(dev_out);
2223 goto out; /* Wrong error code */
2224 }
2225
2226 if (LOCAL_MCAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
2227 if (!fl.fl4_src)
2228 fl.fl4_src = inet_select_addr(dev_out, 0,
2229 RT_SCOPE_LINK);
2230 goto make_route;
2231 }
2232 if (!fl.fl4_src) {
2233 if (MULTICAST(oldflp->fl4_dst))
2234 fl.fl4_src = inet_select_addr(dev_out, 0,
2235 fl.fl4_scope);
2236 else if (!oldflp->fl4_dst)
2237 fl.fl4_src = inet_select_addr(dev_out, 0,
2238 RT_SCOPE_HOST);
2239 }
2240 }
2241
2242 if (!fl.fl4_dst) {
2243 fl.fl4_dst = fl.fl4_src;
2244 if (!fl.fl4_dst)
2245 fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
2246 if (dev_out)
2247 dev_put(dev_out);
2248 dev_out = &loopback_dev;
2249 dev_hold(dev_out);
2250 fl.oif = loopback_dev.ifindex;
2251 res.type = RTN_LOCAL;
2252 flags |= RTCF_LOCAL;
2253 goto make_route;
2254 }
2255
2256 if (fib_lookup(&fl, &res)) {
2257 res.fi = NULL;
2258 if (oldflp->oif) {
2259 /* Apparently, routing tables are wrong. Assume,
2260 that the destination is on link.
2261
2262 WHY? DW.
2263 Because we are allowed to send to iface
2264 even if it has NO routes and NO assigned
2265 addresses. When oif is specified, routing
2266 tables are looked up with only one purpose:
2267 to catch if destination is gatewayed, rather than
2268 direct. Moreover, if MSG_DONTROUTE is set,
2269 we send packet, ignoring both routing tables
2270 and ifaddr state. --ANK
2271
2272
2273 We could make it even if oif is unknown,
2274 likely IPv6, but we do not.
2275 */
2276
2277 if (fl.fl4_src == 0)
2278 fl.fl4_src = inet_select_addr(dev_out, 0,
2279 RT_SCOPE_LINK);
2280 res.type = RTN_UNICAST;
2281 goto make_route;
2282 }
2283 if (dev_out)
2284 dev_put(dev_out);
2285 err = -ENETUNREACH;
2286 goto out;
2287 }
2288 free_res = 1;
2289
2290 if (res.type == RTN_LOCAL) {
2291 if (!fl.fl4_src)
2292 fl.fl4_src = fl.fl4_dst;
2293 if (dev_out)
2294 dev_put(dev_out);
2295 dev_out = &loopback_dev;
2296 dev_hold(dev_out);
2297 fl.oif = dev_out->ifindex;
2298 if (res.fi)
2299 fib_info_put(res.fi);
2300 res.fi = NULL;
2301 flags |= RTCF_LOCAL;
2302 goto make_route;
2303 }
2304
2305 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2306 if (res.fi->fib_nhs > 1 && fl.oif == 0)
2307 fib_select_multipath(&fl, &res);
2308 else
2309 #endif
2310 if (!res.prefixlen && res.type == RTN_UNICAST && !fl.oif)
2311 fib_select_default(&fl, &res);
2312
2313 if (!fl.fl4_src)
2314 fl.fl4_src = FIB_RES_PREFSRC(res);
2315
2316 if (dev_out)
2317 dev_put(dev_out);
2318 dev_out = FIB_RES_DEV(res);
2319 dev_hold(dev_out);
2320 fl.oif = dev_out->ifindex;
2321
2322
2323 make_route:
2324 err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
2325
2326
2327 if (free_res)
2328 fib_res_put(&res);
2329 if (dev_out)
2330 dev_put(dev_out);
2331 out: return err;
2332 }
2333
2334 int __ip_route_output_key(struct rtable **rp, const struct flowi *flp)
2335 {
2336 unsigned hash;
2337 struct rtable *rth;
2338
2339 hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif);
2340
2341 rcu_read_lock_bh();
2342 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2343 rth = rcu_dereference(rth->u.dst.rt_next)) {
2344 if (rth->fl.fl4_dst == flp->fl4_dst &&
2345 rth->fl.fl4_src == flp->fl4_src &&
2346 rth->fl.iif == 0 &&
2347 rth->fl.oif == flp->oif &&
2348 rth->fl.mark == flp->mark &&
2349 !((rth->fl.fl4_tos ^ flp->fl4_tos) &
2350 (IPTOS_RT_MASK | RTO_ONLINK))) {
2351 rth->u.dst.lastuse = jiffies;
2352 dst_hold(&rth->u.dst);
2353 rth->u.dst.__use++;
2354 RT_CACHE_STAT_INC(out_hit);
2355 rcu_read_unlock_bh();
2356 *rp = rth;
2357 return 0;
2358 }
2359 RT_CACHE_STAT_INC(out_hlist_search);
2360 }
2361 rcu_read_unlock_bh();
2362
2363 return ip_route_output_slow(rp, flp);
2364 }
2365
2366 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2367
2368 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2369 {
2370 }
2371
2372 static struct dst_ops ipv4_dst_blackhole_ops = {
2373 .family = AF_INET,
2374 .protocol = __constant_htons(ETH_P_IP),
2375 .destroy = ipv4_dst_destroy,
2376 .check = ipv4_dst_check,
2377 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2378 .entry_size = sizeof(struct rtable),
2379 };
2380
2381
2382 static int ipv4_blackhole_output(struct sk_buff *skb)
2383 {
2384 kfree_skb(skb);
2385 return 0;
2386 }
2387
2388 static int ipv4_dst_blackhole(struct rtable **rp, struct flowi *flp, struct sock *sk)
2389 {
2390 struct rtable *ort = *rp;
2391 struct rtable *rt = (struct rtable *)
2392 dst_alloc(&ipv4_dst_blackhole_ops);
2393
2394 if (rt) {
2395 struct dst_entry *new = &rt->u.dst;
2396
2397 atomic_set(&new->__refcnt, 1);
2398 new->__use = 1;
2399 new->input = ipv4_blackhole_output;
2400 new->output = ipv4_blackhole_output;
2401 memcpy(new->metrics, ort->u.dst.metrics, RTAX_MAX*sizeof(u32));
2402
2403 new->dev = ort->u.dst.dev;
2404 if (new->dev)
2405 dev_hold(new->dev);
2406
2407 rt->fl = ort->fl;
2408
2409 rt->idev = ort->idev;
2410 if (rt->idev)
2411 in_dev_hold(rt->idev);
2412 rt->rt_flags = ort->rt_flags;
2413 rt->rt_type = ort->rt_type;
2414 rt->rt_dst = ort->rt_dst;
2415 rt->rt_src = ort->rt_src;
2416 rt->rt_iif = ort->rt_iif;
2417 rt->rt_gateway = ort->rt_gateway;
2418 rt->rt_spec_dst = ort->rt_spec_dst;
2419 rt->peer = ort->peer;
2420 if (rt->peer)
2421 atomic_inc(&rt->peer->refcnt);
2422
2423 dst_free(new);
2424 }
2425
2426 dst_release(&(*rp)->u.dst);
2427 *rp = rt;
2428 return (rt ? 0 : -ENOMEM);
2429 }
2430
2431 int ip_route_output_flow(struct rtable **rp, struct flowi *flp, struct sock *sk, int flags)
2432 {
2433 int err;
2434
2435 if ((err = __ip_route_output_key(rp, flp)) != 0)
2436 return err;
2437
2438 if (flp->proto) {
2439 if (!flp->fl4_src)
2440 flp->fl4_src = (*rp)->rt_src;
2441 if (!flp->fl4_dst)
2442 flp->fl4_dst = (*rp)->rt_dst;
2443 err = __xfrm_lookup((struct dst_entry **)rp, flp, sk, flags);
2444 if (err == -EREMOTE)
2445 err = ipv4_dst_blackhole(rp, flp, sk);
2446
2447 return err;
2448 }
2449
2450 return 0;
2451 }
2452
2453 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2454
2455 int ip_route_output_key(struct rtable **rp, struct flowi *flp)
2456 {
2457 return ip_route_output_flow(rp, flp, NULL, 0);
2458 }
2459
2460 static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
2461 int nowait, unsigned int flags)
2462 {
2463 struct rtable *rt = (struct rtable*)skb->dst;
2464 struct rtmsg *r;
2465 struct nlmsghdr *nlh;
2466 long expires;
2467 u32 id = 0, ts = 0, tsage = 0, error;
2468
2469 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2470 if (nlh == NULL)
2471 return -EMSGSIZE;
2472
2473 r = nlmsg_data(nlh);
2474 r->rtm_family = AF_INET;
2475 r->rtm_dst_len = 32;
2476 r->rtm_src_len = 0;
2477 r->rtm_tos = rt->fl.fl4_tos;
2478 r->rtm_table = RT_TABLE_MAIN;
2479 NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
2480 r->rtm_type = rt->rt_type;
2481 r->rtm_scope = RT_SCOPE_UNIVERSE;
2482 r->rtm_protocol = RTPROT_UNSPEC;
2483 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2484 if (rt->rt_flags & RTCF_NOTIFY)
2485 r->rtm_flags |= RTM_F_NOTIFY;
2486
2487 NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2488
2489 if (rt->fl.fl4_src) {
2490 r->rtm_src_len = 32;
2491 NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src);
2492 }
2493 if (rt->u.dst.dev)
2494 NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex);
2495 #ifdef CONFIG_NET_CLS_ROUTE
2496 if (rt->u.dst.tclassid)
2497 NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid);
2498 #endif
2499 if (rt->fl.iif)
2500 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
2501 else if (rt->rt_src != rt->fl.fl4_src)
2502 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2503
2504 if (rt->rt_dst != rt->rt_gateway)
2505 NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2506
2507 if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2508 goto nla_put_failure;
2509
2510 error = rt->u.dst.error;
2511 expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
2512 if (rt->peer) {
2513 id = rt->peer->ip_id_count;
2514 if (rt->peer->tcp_ts_stamp) {
2515 ts = rt->peer->tcp_ts;
2516 tsage = get_seconds() - rt->peer->tcp_ts_stamp;
2517 }
2518 }
2519
2520 if (rt->fl.iif) {
2521 #ifdef CONFIG_IP_MROUTE
2522 __be32 dst = rt->rt_dst;
2523
2524 if (MULTICAST(dst) && !LOCAL_MCAST(dst) &&
2525 IPV4_DEVCONF_ALL(MC_FORWARDING)) {
2526 int err = ipmr_get_route(skb, r, nowait);
2527 if (err <= 0) {
2528 if (!nowait) {
2529 if (err == 0)
2530 return 0;
2531 goto nla_put_failure;
2532 } else {
2533 if (err == -EMSGSIZE)
2534 goto nla_put_failure;
2535 error = err;
2536 }
2537 }
2538 } else
2539 #endif
2540 NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif);
2541 }
2542
2543 if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage,
2544 expires, error) < 0)
2545 goto nla_put_failure;
2546
2547 return nlmsg_end(skb, nlh);
2548
2549 nla_put_failure:
2550 nlmsg_cancel(skb, nlh);
2551 return -EMSGSIZE;
2552 }
2553
2554 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
2555 {
2556 struct rtmsg *rtm;
2557 struct nlattr *tb[RTA_MAX+1];
2558 struct rtable *rt = NULL;
2559 __be32 dst = 0;
2560 __be32 src = 0;
2561 u32 iif;
2562 int err;
2563 struct sk_buff *skb;
2564
2565 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2566 if (err < 0)
2567 goto errout;
2568
2569 rtm = nlmsg_data(nlh);
2570
2571 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2572 if (skb == NULL) {
2573 err = -ENOBUFS;
2574 goto errout;
2575 }
2576
2577 /* Reserve room for dummy headers, this skb can pass
2578 through good chunk of routing engine.
2579 */
2580 skb_reset_mac_header(skb);
2581 skb_reset_network_header(skb);
2582
2583 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2584 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2585 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2586
2587 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2588 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2589 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2590
2591 if (iif) {
2592 struct net_device *dev;
2593
2594 dev = __dev_get_by_index(iif);
2595 if (dev == NULL) {
2596 err = -ENODEV;
2597 goto errout_free;
2598 }
2599
2600 skb->protocol = htons(ETH_P_IP);
2601 skb->dev = dev;
2602 local_bh_disable();
2603 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2604 local_bh_enable();
2605
2606 rt = (struct rtable*) skb->dst;
2607 if (err == 0 && rt->u.dst.error)
2608 err = -rt->u.dst.error;
2609 } else {
2610 struct flowi fl = {
2611 .nl_u = {
2612 .ip4_u = {
2613 .daddr = dst,
2614 .saddr = src,
2615 .tos = rtm->rtm_tos,
2616 },
2617 },
2618 .oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
2619 };
2620 err = ip_route_output_key(&rt, &fl);
2621 }
2622
2623 if (err)
2624 goto errout_free;
2625
2626 skb->dst = &rt->u.dst;
2627 if (rtm->rtm_flags & RTM_F_NOTIFY)
2628 rt->rt_flags |= RTCF_NOTIFY;
2629
2630 err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2631 RTM_NEWROUTE, 0, 0);
2632 if (err <= 0)
2633 goto errout_free;
2634
2635 err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
2636 errout:
2637 return err;
2638
2639 errout_free:
2640 kfree_skb(skb);
2641 goto errout;
2642 }
2643
2644 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
2645 {
2646 struct rtable *rt;
2647 int h, s_h;
2648 int idx, s_idx;
2649
2650 s_h = cb->args[0];
2651 s_idx = idx = cb->args[1];
2652 for (h = 0; h <= rt_hash_mask; h++) {
2653 if (h < s_h) continue;
2654 if (h > s_h)
2655 s_idx = 0;
2656 rcu_read_lock_bh();
2657 for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
2658 rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
2659 if (idx < s_idx)
2660 continue;
2661 skb->dst = dst_clone(&rt->u.dst);
2662 if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
2663 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2664 1, NLM_F_MULTI) <= 0) {
2665 dst_release(xchg(&skb->dst, NULL));
2666 rcu_read_unlock_bh();
2667 goto done;
2668 }
2669 dst_release(xchg(&skb->dst, NULL));
2670 }
2671 rcu_read_unlock_bh();
2672 }
2673
2674 done:
2675 cb->args[0] = h;
2676 cb->args[1] = idx;
2677 return skb->len;
2678 }
2679
2680 void ip_rt_multicast_event(struct in_device *in_dev)
2681 {
2682 rt_cache_flush(0);
2683 }
2684
2685 #ifdef CONFIG_SYSCTL
2686 static int flush_delay;
2687
2688 static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write,
2689 struct file *filp, void __user *buffer,
2690 size_t *lenp, loff_t *ppos)
2691 {
2692 if (write) {
2693 proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
2694 rt_cache_flush(flush_delay);
2695 return 0;
2696 }
2697
2698 return -EINVAL;
2699 }
2700
2701 static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table,
2702 int __user *name,
2703 int nlen,
2704 void __user *oldval,
2705 size_t __user *oldlenp,
2706 void __user *newval,
2707 size_t newlen)
2708 {
2709 int delay;
2710 if (newlen != sizeof(int))
2711 return -EINVAL;
2712 if (get_user(delay, (int __user *)newval))
2713 return -EFAULT;
2714 rt_cache_flush(delay);
2715 return 0;
2716 }
2717
2718 ctl_table ipv4_route_table[] = {
2719 {
2720 .ctl_name = NET_IPV4_ROUTE_FLUSH,
2721 .procname = "flush",
2722 .data = &flush_delay,
2723 .maxlen = sizeof(int),
2724 .mode = 0200,
2725 .proc_handler = &ipv4_sysctl_rtcache_flush,
2726 .strategy = &ipv4_sysctl_rtcache_flush_strategy,
2727 },
2728 {
2729 .ctl_name = NET_IPV4_ROUTE_MIN_DELAY,
2730 .procname = "min_delay",
2731 .data = &ip_rt_min_delay,
2732 .maxlen = sizeof(int),
2733 .mode = 0644,
2734 .proc_handler = &proc_dointvec_jiffies,
2735 .strategy = &sysctl_jiffies,
2736 },
2737 {
2738 .ctl_name = NET_IPV4_ROUTE_MAX_DELAY,
2739 .procname = "max_delay",
2740 .data = &ip_rt_max_delay,
2741 .maxlen = sizeof(int),
2742 .mode = 0644,
2743 .proc_handler = &proc_dointvec_jiffies,
2744 .strategy = &sysctl_jiffies,
2745 },
2746 {
2747 .ctl_name = NET_IPV4_ROUTE_GC_THRESH,
2748 .procname = "gc_thresh",
2749 .data = &ipv4_dst_ops.gc_thresh,
2750 .maxlen = sizeof(int),
2751 .mode = 0644,
2752 .proc_handler = &proc_dointvec,
2753 },
2754 {
2755 .ctl_name = NET_IPV4_ROUTE_MAX_SIZE,
2756 .procname = "max_size",
2757 .data = &ip_rt_max_size,
2758 .maxlen = sizeof(int),
2759 .mode = 0644,
2760 .proc_handler = &proc_dointvec,
2761 },
2762 {
2763 /* Deprecated. Use gc_min_interval_ms */
2764
2765 .ctl_name = NET_IPV4_ROUTE_GC_MIN_INTERVAL,
2766 .procname = "gc_min_interval",
2767 .data = &ip_rt_gc_min_interval,
2768 .maxlen = sizeof(int),
2769 .mode = 0644,
2770 .proc_handler = &proc_dointvec_jiffies,
2771 .strategy = &sysctl_jiffies,
2772 },
2773 {
2774 .ctl_name = NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS,
2775 .procname = "gc_min_interval_ms",
2776 .data = &ip_rt_gc_min_interval,
2777 .maxlen = sizeof(int),
2778 .mode = 0644,
2779 .proc_handler = &proc_dointvec_ms_jiffies,
2780 .strategy = &sysctl_ms_jiffies,
2781 },
2782 {
2783 .ctl_name = NET_IPV4_ROUTE_GC_TIMEOUT,
2784 .procname = "gc_timeout",
2785 .data = &ip_rt_gc_timeout,
2786 .maxlen = sizeof(int),
2787 .mode = 0644,
2788 .proc_handler = &proc_dointvec_jiffies,
2789 .strategy = &sysctl_jiffies,
2790 },
2791 {
2792 .ctl_name = NET_IPV4_ROUTE_GC_INTERVAL,
2793 .procname = "gc_interval",
2794 .data = &ip_rt_gc_interval,
2795 .maxlen = sizeof(int),
2796 .mode = 0644,
2797 .proc_handler = &proc_dointvec_jiffies,
2798 .strategy = &sysctl_jiffies,
2799 },
2800 {
2801 .ctl_name = NET_IPV4_ROUTE_REDIRECT_LOAD,
2802 .procname = "redirect_load",
2803 .data = &ip_rt_redirect_load,
2804 .maxlen = sizeof(int),
2805 .mode = 0644,
2806 .proc_handler = &proc_dointvec,
2807 },
2808 {
2809 .ctl_name = NET_IPV4_ROUTE_REDIRECT_NUMBER,
2810 .procname = "redirect_number",
2811 .data = &ip_rt_redirect_number,
2812 .maxlen = sizeof(int),
2813 .mode = 0644,
2814 .proc_handler = &proc_dointvec,
2815 },
2816 {
2817 .ctl_name = NET_IPV4_ROUTE_REDIRECT_SILENCE,
2818 .procname = "redirect_silence",
2819 .data = &ip_rt_redirect_silence,
2820 .maxlen = sizeof(int),
2821 .mode = 0644,
2822 .proc_handler = &proc_dointvec,
2823 },
2824 {
2825 .ctl_name = NET_IPV4_ROUTE_ERROR_COST,
2826 .procname = "error_cost",
2827 .data = &ip_rt_error_cost,
2828 .maxlen = sizeof(int),
2829 .mode = 0644,
2830 .proc_handler = &proc_dointvec,
2831 },
2832 {
2833 .ctl_name = NET_IPV4_ROUTE_ERROR_BURST,
2834 .procname = "error_burst",
2835 .data = &ip_rt_error_burst,
2836 .maxlen = sizeof(int),
2837 .mode = 0644,
2838 .proc_handler = &proc_dointvec,
2839 },
2840 {
2841 .ctl_name = NET_IPV4_ROUTE_GC_ELASTICITY,
2842 .procname = "gc_elasticity",
2843 .data = &ip_rt_gc_elasticity,
2844 .maxlen = sizeof(int),
2845 .mode = 0644,
2846 .proc_handler = &proc_dointvec,
2847 },
2848 {
2849 .ctl_name = NET_IPV4_ROUTE_MTU_EXPIRES,
2850 .procname = "mtu_expires",
2851 .data = &ip_rt_mtu_expires,
2852 .maxlen = sizeof(int),
2853 .mode = 0644,
2854 .proc_handler = &proc_dointvec_jiffies,
2855 .strategy = &sysctl_jiffies,
2856 },
2857 {
2858 .ctl_name = NET_IPV4_ROUTE_MIN_PMTU,
2859 .procname = "min_pmtu",
2860 .data = &ip_rt_min_pmtu,
2861 .maxlen = sizeof(int),
2862 .mode = 0644,
2863 .proc_handler = &proc_dointvec,
2864 },
2865 {
2866 .ctl_name = NET_IPV4_ROUTE_MIN_ADVMSS,
2867 .procname = "min_adv_mss",
2868 .data = &ip_rt_min_advmss,
2869 .maxlen = sizeof(int),
2870 .mode = 0644,
2871 .proc_handler = &proc_dointvec,
2872 },
2873 {
2874 .ctl_name = NET_IPV4_ROUTE_SECRET_INTERVAL,
2875 .procname = "secret_interval",
2876 .data = &ip_rt_secret_interval,
2877 .maxlen = sizeof(int),
2878 .mode = 0644,
2879 .proc_handler = &proc_dointvec_jiffies,
2880 .strategy = &sysctl_jiffies,
2881 },
2882 { .ctl_name = 0 }
2883 };
2884 #endif
2885
2886 #ifdef CONFIG_NET_CLS_ROUTE
2887 struct ip_rt_acct *ip_rt_acct;
2888
2889 /* This code sucks. But you should have seen it before! --RR */
2890
2891 /* IP route accounting ptr for this logical cpu number. */
2892 #define IP_RT_ACCT_CPU(i) (ip_rt_acct + i * 256)
2893
2894 #ifdef CONFIG_PROC_FS
2895 static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
2896 int length, int *eof, void *data)
2897 {
2898 unsigned int i;
2899
2900 if ((offset & 3) || (length & 3))
2901 return -EIO;
2902
2903 if (offset >= sizeof(struct ip_rt_acct) * 256) {
2904 *eof = 1;
2905 return 0;
2906 }
2907
2908 if (offset + length >= sizeof(struct ip_rt_acct) * 256) {
2909 length = sizeof(struct ip_rt_acct) * 256 - offset;
2910 *eof = 1;
2911 }
2912
2913 offset /= sizeof(u32);
2914
2915 if (length > 0) {
2916 u32 *src = ((u32 *) IP_RT_ACCT_CPU(0)) + offset;
2917 u32 *dst = (u32 *) buffer;
2918
2919 /* Copy first cpu. */
2920 *start = buffer;
2921 memcpy(dst, src, length);
2922
2923 /* Add the other cpus in, one int at a time */
2924 for_each_possible_cpu(i) {
2925 unsigned int j;
2926
2927 src = ((u32 *) IP_RT_ACCT_CPU(i)) + offset;
2928
2929 for (j = 0; j < length/4; j++)
2930 dst[j] += src[j];
2931 }
2932 }
2933 return length;
2934 }
2935 #endif /* CONFIG_PROC_FS */
2936 #endif /* CONFIG_NET_CLS_ROUTE */
2937
2938 static __initdata unsigned long rhash_entries;
2939 static int __init set_rhash_entries(char *str)
2940 {
2941 if (!str)
2942 return 0;
2943 rhash_entries = simple_strtoul(str, &str, 0);
2944 return 1;
2945 }
2946 __setup("rhash_entries=", set_rhash_entries);
2947
2948 int __init ip_rt_init(void)
2949 {
2950 int rc = 0;
2951
2952 rt_hash_rnd = (int) ((num_physpages ^ (num_physpages>>8)) ^
2953 (jiffies ^ (jiffies >> 7)));
2954
2955 #ifdef CONFIG_NET_CLS_ROUTE
2956 {
2957 int order;
2958 for (order = 0;
2959 (PAGE_SIZE << order) < 256 * sizeof(struct ip_rt_acct) * NR_CPUS; order++)
2960 /* NOTHING */;
2961 ip_rt_acct = (struct ip_rt_acct *)__get_free_pages(GFP_KERNEL, order);
2962 if (!ip_rt_acct)
2963 panic("IP: failed to allocate ip_rt_acct\n");
2964 memset(ip_rt_acct, 0, PAGE_SIZE << order);
2965 }
2966 #endif
2967
2968 ipv4_dst_ops.kmem_cachep =
2969 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2970 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2971
2972 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2973
2974 rt_hash_table = (struct rt_hash_bucket *)
2975 alloc_large_system_hash("IP route cache",
2976 sizeof(struct rt_hash_bucket),
2977 rhash_entries,
2978 (num_physpages >= 128 * 1024) ?
2979 15 : 17,
2980 0,
2981 &rt_hash_log,
2982 &rt_hash_mask,
2983 0);
2984 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
2985 rt_hash_lock_init();
2986
2987 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
2988 ip_rt_max_size = (rt_hash_mask + 1) * 16;
2989
2990 devinet_init();
2991 ip_fib_init();
2992
2993 init_timer(&rt_flush_timer);
2994 rt_flush_timer.function = rt_run_flush;
2995 init_timer(&rt_periodic_timer);
2996 rt_periodic_timer.function = rt_check_expire;
2997 init_timer(&rt_secret_timer);
2998 rt_secret_timer.function = rt_secret_rebuild;
2999
3000 /* All the timers, started at system startup tend
3001 to synchronize. Perturb it a bit.
3002 */
3003 rt_periodic_timer.expires = jiffies + net_random() % ip_rt_gc_interval +
3004 ip_rt_gc_interval;
3005 add_timer(&rt_periodic_timer);
3006
3007 rt_secret_timer.expires = jiffies + net_random() % ip_rt_secret_interval +
3008 ip_rt_secret_interval;
3009 add_timer(&rt_secret_timer);
3010
3011 #ifdef CONFIG_PROC_FS
3012 {
3013 struct proc_dir_entry *rtstat_pde = NULL; /* keep gcc happy */
3014 if (!proc_net_fops_create("rt_cache", S_IRUGO, &rt_cache_seq_fops) ||
3015 !(rtstat_pde = create_proc_entry("rt_cache", S_IRUGO,
3016 proc_net_stat))) {
3017 return -ENOMEM;
3018 }
3019 rtstat_pde->proc_fops = &rt_cpu_seq_fops;
3020 }
3021 #ifdef CONFIG_NET_CLS_ROUTE
3022 create_proc_read_entry("rt_acct", 0, proc_net, ip_rt_acct_read, NULL);
3023 #endif
3024 #endif
3025 #ifdef CONFIG_XFRM
3026 xfrm_init();
3027 xfrm4_init();
3028 #endif
3029 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);
3030
3031 return rc;
3032 }
3033
3034 EXPORT_SYMBOL(__ip_select_ident);
3035 EXPORT_SYMBOL(ip_route_input);
3036 EXPORT_SYMBOL(ip_route_output_key);
USB Experimental Work