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ipv4, fib: pass LOOPBACK_IFINDEX instead of 0 to flowi4_iif
[deliverable/linux.git] / net / ipv4 / fib_semantics.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * IPv4 Forwarding Information Base: semantics.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16 #include <asm/uaccess.h>
17 #include <linux/bitops.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/jiffies.h>
21 #include <linux/mm.h>
22 #include <linux/string.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/errno.h>
26 #include <linux/in.h>
27 #include <linux/inet.h>
28 #include <linux/inetdevice.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/proc_fs.h>
32 #include <linux/skbuff.h>
33 #include <linux/init.h>
34 #include <linux/slab.h>
35
36 #include <net/arp.h>
37 #include <net/ip.h>
38 #include <net/protocol.h>
39 #include <net/route.h>
40 #include <net/tcp.h>
41 #include <net/sock.h>
42 #include <net/ip_fib.h>
43 #include <net/netlink.h>
44 #include <net/nexthop.h>
45
46 #include "fib_lookup.h"
47
48 static DEFINE_SPINLOCK(fib_info_lock);
49 static struct hlist_head *fib_info_hash;
50 static struct hlist_head *fib_info_laddrhash;
51 static unsigned int fib_info_hash_size;
52 static unsigned int fib_info_cnt;
53
54 #define DEVINDEX_HASHBITS 8
55 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
56 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
57
58 #ifdef CONFIG_IP_ROUTE_MULTIPATH
59
60 static DEFINE_SPINLOCK(fib_multipath_lock);
61
62 #define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68 #define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74 #else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76 /* Hope, that gcc will optimize it to get rid of dummy loop */
77
78 #define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82 #define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89 #define endfor_nexthops(fi) }
90
91
92 const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141 };
142
143 static void rt_fibinfo_free(struct rtable __rcu **rtp)
144 {
145 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
146
147 if (!rt)
148 return;
149
150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
151 * because we waited an RCU grace period before calling
152 * free_fib_info_rcu()
153 */
154
155 dst_free(&rt->dst);
156 }
157
158 static void free_nh_exceptions(struct fib_nh *nh)
159 {
160 struct fnhe_hash_bucket *hash = nh->nh_exceptions;
161 int i;
162
163 for (i = 0; i < FNHE_HASH_SIZE; i++) {
164 struct fib_nh_exception *fnhe;
165
166 fnhe = rcu_dereference_protected(hash[i].chain, 1);
167 while (fnhe) {
168 struct fib_nh_exception *next;
169
170 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
171
172 rt_fibinfo_free(&fnhe->fnhe_rth_input);
173 rt_fibinfo_free(&fnhe->fnhe_rth_output);
174
175 kfree(fnhe);
176
177 fnhe = next;
178 }
179 }
180 kfree(hash);
181 }
182
183 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
184 {
185 int cpu;
186
187 if (!rtp)
188 return;
189
190 for_each_possible_cpu(cpu) {
191 struct rtable *rt;
192
193 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
194 if (rt)
195 dst_free(&rt->dst);
196 }
197 free_percpu(rtp);
198 }
199
200 /* Release a nexthop info record */
201 static void free_fib_info_rcu(struct rcu_head *head)
202 {
203 struct fib_info *fi = container_of(head, struct fib_info, rcu);
204
205 change_nexthops(fi) {
206 if (nexthop_nh->nh_dev)
207 dev_put(nexthop_nh->nh_dev);
208 if (nexthop_nh->nh_exceptions)
209 free_nh_exceptions(nexthop_nh);
210 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
211 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
212 } endfor_nexthops(fi);
213
214 release_net(fi->fib_net);
215 if (fi->fib_metrics != (u32 *) dst_default_metrics)
216 kfree(fi->fib_metrics);
217 kfree(fi);
218 }
219
220 void free_fib_info(struct fib_info *fi)
221 {
222 if (fi->fib_dead == 0) {
223 pr_warn("Freeing alive fib_info %p\n", fi);
224 return;
225 }
226 fib_info_cnt--;
227 #ifdef CONFIG_IP_ROUTE_CLASSID
228 change_nexthops(fi) {
229 if (nexthop_nh->nh_tclassid)
230 fi->fib_net->ipv4.fib_num_tclassid_users--;
231 } endfor_nexthops(fi);
232 #endif
233 call_rcu(&fi->rcu, free_fib_info_rcu);
234 }
235
236 void fib_release_info(struct fib_info *fi)
237 {
238 spin_lock_bh(&fib_info_lock);
239 if (fi && --fi->fib_treeref == 0) {
240 hlist_del(&fi->fib_hash);
241 if (fi->fib_prefsrc)
242 hlist_del(&fi->fib_lhash);
243 change_nexthops(fi) {
244 if (!nexthop_nh->nh_dev)
245 continue;
246 hlist_del(&nexthop_nh->nh_hash);
247 } endfor_nexthops(fi)
248 fi->fib_dead = 1;
249 fib_info_put(fi);
250 }
251 spin_unlock_bh(&fib_info_lock);
252 }
253
254 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
255 {
256 const struct fib_nh *onh = ofi->fib_nh;
257
258 for_nexthops(fi) {
259 if (nh->nh_oif != onh->nh_oif ||
260 nh->nh_gw != onh->nh_gw ||
261 nh->nh_scope != onh->nh_scope ||
262 #ifdef CONFIG_IP_ROUTE_MULTIPATH
263 nh->nh_weight != onh->nh_weight ||
264 #endif
265 #ifdef CONFIG_IP_ROUTE_CLASSID
266 nh->nh_tclassid != onh->nh_tclassid ||
267 #endif
268 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
269 return -1;
270 onh++;
271 } endfor_nexthops(fi);
272 return 0;
273 }
274
275 static inline unsigned int fib_devindex_hashfn(unsigned int val)
276 {
277 unsigned int mask = DEVINDEX_HASHSIZE - 1;
278
279 return (val ^
280 (val >> DEVINDEX_HASHBITS) ^
281 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
282 }
283
284 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
285 {
286 unsigned int mask = (fib_info_hash_size - 1);
287 unsigned int val = fi->fib_nhs;
288
289 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
290 val ^= (__force u32)fi->fib_prefsrc;
291 val ^= fi->fib_priority;
292 for_nexthops(fi) {
293 val ^= fib_devindex_hashfn(nh->nh_oif);
294 } endfor_nexthops(fi)
295
296 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
297 }
298
299 static struct fib_info *fib_find_info(const struct fib_info *nfi)
300 {
301 struct hlist_head *head;
302 struct fib_info *fi;
303 unsigned int hash;
304
305 hash = fib_info_hashfn(nfi);
306 head = &fib_info_hash[hash];
307
308 hlist_for_each_entry(fi, head, fib_hash) {
309 if (!net_eq(fi->fib_net, nfi->fib_net))
310 continue;
311 if (fi->fib_nhs != nfi->fib_nhs)
312 continue;
313 if (nfi->fib_protocol == fi->fib_protocol &&
314 nfi->fib_scope == fi->fib_scope &&
315 nfi->fib_prefsrc == fi->fib_prefsrc &&
316 nfi->fib_priority == fi->fib_priority &&
317 nfi->fib_type == fi->fib_type &&
318 memcmp(nfi->fib_metrics, fi->fib_metrics,
319 sizeof(u32) * RTAX_MAX) == 0 &&
320 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
321 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
322 return fi;
323 }
324
325 return NULL;
326 }
327
328 /* Check, that the gateway is already configured.
329 * Used only by redirect accept routine.
330 */
331 int ip_fib_check_default(__be32 gw, struct net_device *dev)
332 {
333 struct hlist_head *head;
334 struct fib_nh *nh;
335 unsigned int hash;
336
337 spin_lock(&fib_info_lock);
338
339 hash = fib_devindex_hashfn(dev->ifindex);
340 head = &fib_info_devhash[hash];
341 hlist_for_each_entry(nh, head, nh_hash) {
342 if (nh->nh_dev == dev &&
343 nh->nh_gw == gw &&
344 !(nh->nh_flags & RTNH_F_DEAD)) {
345 spin_unlock(&fib_info_lock);
346 return 0;
347 }
348 }
349
350 spin_unlock(&fib_info_lock);
351
352 return -1;
353 }
354
355 static inline size_t fib_nlmsg_size(struct fib_info *fi)
356 {
357 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
358 + nla_total_size(4) /* RTA_TABLE */
359 + nla_total_size(4) /* RTA_DST */
360 + nla_total_size(4) /* RTA_PRIORITY */
361 + nla_total_size(4); /* RTA_PREFSRC */
362
363 /* space for nested metrics */
364 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
365
366 if (fi->fib_nhs) {
367 /* Also handles the special case fib_nhs == 1 */
368
369 /* each nexthop is packed in an attribute */
370 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
371
372 /* may contain flow and gateway attribute */
373 nhsize += 2 * nla_total_size(4);
374
375 /* all nexthops are packed in a nested attribute */
376 payload += nla_total_size(fi->fib_nhs * nhsize);
377 }
378
379 return payload;
380 }
381
382 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
383 int dst_len, u32 tb_id, const struct nl_info *info,
384 unsigned int nlm_flags)
385 {
386 struct sk_buff *skb;
387 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
388 int err = -ENOBUFS;
389
390 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
391 if (skb == NULL)
392 goto errout;
393
394 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
395 fa->fa_type, key, dst_len,
396 fa->fa_tos, fa->fa_info, nlm_flags);
397 if (err < 0) {
398 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
399 WARN_ON(err == -EMSGSIZE);
400 kfree_skb(skb);
401 goto errout;
402 }
403 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
404 info->nlh, GFP_KERNEL);
405 return;
406 errout:
407 if (err < 0)
408 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
409 }
410
411 /* Return the first fib alias matching TOS with
412 * priority less than or equal to PRIO.
413 */
414 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
415 {
416 if (fah) {
417 struct fib_alias *fa;
418 list_for_each_entry(fa, fah, fa_list) {
419 if (fa->fa_tos > tos)
420 continue;
421 if (fa->fa_info->fib_priority >= prio ||
422 fa->fa_tos < tos)
423 return fa;
424 }
425 }
426 return NULL;
427 }
428
429 static int fib_detect_death(struct fib_info *fi, int order,
430 struct fib_info **last_resort, int *last_idx,
431 int dflt)
432 {
433 struct neighbour *n;
434 int state = NUD_NONE;
435
436 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
437 if (n) {
438 state = n->nud_state;
439 neigh_release(n);
440 }
441 if (state == NUD_REACHABLE)
442 return 0;
443 if ((state & NUD_VALID) && order != dflt)
444 return 0;
445 if ((state & NUD_VALID) ||
446 (*last_idx < 0 && order > dflt)) {
447 *last_resort = fi;
448 *last_idx = order;
449 }
450 return 1;
451 }
452
453 #ifdef CONFIG_IP_ROUTE_MULTIPATH
454
455 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
456 {
457 int nhs = 0;
458
459 while (rtnh_ok(rtnh, remaining)) {
460 nhs++;
461 rtnh = rtnh_next(rtnh, &remaining);
462 }
463
464 /* leftover implies invalid nexthop configuration, discard it */
465 return remaining > 0 ? 0 : nhs;
466 }
467
468 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
469 int remaining, struct fib_config *cfg)
470 {
471 change_nexthops(fi) {
472 int attrlen;
473
474 if (!rtnh_ok(rtnh, remaining))
475 return -EINVAL;
476
477 nexthop_nh->nh_flags =
478 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
479 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
480 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
481
482 attrlen = rtnh_attrlen(rtnh);
483 if (attrlen > 0) {
484 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
485
486 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
487 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
488 #ifdef CONFIG_IP_ROUTE_CLASSID
489 nla = nla_find(attrs, attrlen, RTA_FLOW);
490 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
491 if (nexthop_nh->nh_tclassid)
492 fi->fib_net->ipv4.fib_num_tclassid_users++;
493 #endif
494 }
495
496 rtnh = rtnh_next(rtnh, &remaining);
497 } endfor_nexthops(fi);
498
499 return 0;
500 }
501
502 #endif
503
504 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
505 {
506 #ifdef CONFIG_IP_ROUTE_MULTIPATH
507 struct rtnexthop *rtnh;
508 int remaining;
509 #endif
510
511 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
512 return 1;
513
514 if (cfg->fc_oif || cfg->fc_gw) {
515 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
516 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
517 return 0;
518 return 1;
519 }
520
521 #ifdef CONFIG_IP_ROUTE_MULTIPATH
522 if (cfg->fc_mp == NULL)
523 return 0;
524
525 rtnh = cfg->fc_mp;
526 remaining = cfg->fc_mp_len;
527
528 for_nexthops(fi) {
529 int attrlen;
530
531 if (!rtnh_ok(rtnh, remaining))
532 return -EINVAL;
533
534 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
535 return 1;
536
537 attrlen = rtnh_attrlen(rtnh);
538 if (attrlen < 0) {
539 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
540
541 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
542 if (nla && nla_get_be32(nla) != nh->nh_gw)
543 return 1;
544 #ifdef CONFIG_IP_ROUTE_CLASSID
545 nla = nla_find(attrs, attrlen, RTA_FLOW);
546 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
547 return 1;
548 #endif
549 }
550
551 rtnh = rtnh_next(rtnh, &remaining);
552 } endfor_nexthops(fi);
553 #endif
554 return 0;
555 }
556
557
558 /*
559 * Picture
560 * -------
561 *
562 * Semantics of nexthop is very messy by historical reasons.
563 * We have to take into account, that:
564 * a) gateway can be actually local interface address,
565 * so that gatewayed route is direct.
566 * b) gateway must be on-link address, possibly
567 * described not by an ifaddr, but also by a direct route.
568 * c) If both gateway and interface are specified, they should not
569 * contradict.
570 * d) If we use tunnel routes, gateway could be not on-link.
571 *
572 * Attempt to reconcile all of these (alas, self-contradictory) conditions
573 * results in pretty ugly and hairy code with obscure logic.
574 *
575 * I chose to generalized it instead, so that the size
576 * of code does not increase practically, but it becomes
577 * much more general.
578 * Every prefix is assigned a "scope" value: "host" is local address,
579 * "link" is direct route,
580 * [ ... "site" ... "interior" ... ]
581 * and "universe" is true gateway route with global meaning.
582 *
583 * Every prefix refers to a set of "nexthop"s (gw, oif),
584 * where gw must have narrower scope. This recursion stops
585 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
586 * which means that gw is forced to be on link.
587 *
588 * Code is still hairy, but now it is apparently logically
589 * consistent and very flexible. F.e. as by-product it allows
590 * to co-exists in peace independent exterior and interior
591 * routing processes.
592 *
593 * Normally it looks as following.
594 *
595 * {universe prefix} -> (gw, oif) [scope link]
596 * |
597 * |-> {link prefix} -> (gw, oif) [scope local]
598 * |
599 * |-> {local prefix} (terminal node)
600 */
601 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
602 struct fib_nh *nh)
603 {
604 int err;
605 struct net *net;
606 struct net_device *dev;
607
608 net = cfg->fc_nlinfo.nl_net;
609 if (nh->nh_gw) {
610 struct fib_result res;
611
612 if (nh->nh_flags & RTNH_F_ONLINK) {
613
614 if (cfg->fc_scope >= RT_SCOPE_LINK)
615 return -EINVAL;
616 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
617 return -EINVAL;
618 dev = __dev_get_by_index(net, nh->nh_oif);
619 if (!dev)
620 return -ENODEV;
621 if (!(dev->flags & IFF_UP))
622 return -ENETDOWN;
623 nh->nh_dev = dev;
624 dev_hold(dev);
625 nh->nh_scope = RT_SCOPE_LINK;
626 return 0;
627 }
628 rcu_read_lock();
629 {
630 struct flowi4 fl4 = {
631 .daddr = nh->nh_gw,
632 .flowi4_scope = cfg->fc_scope + 1,
633 .flowi4_oif = nh->nh_oif,
634 .flowi4_iif = LOOPBACK_IFINDEX,
635 };
636
637 /* It is not necessary, but requires a bit of thinking */
638 if (fl4.flowi4_scope < RT_SCOPE_LINK)
639 fl4.flowi4_scope = RT_SCOPE_LINK;
640 err = fib_lookup(net, &fl4, &res);
641 if (err) {
642 rcu_read_unlock();
643 return err;
644 }
645 }
646 err = -EINVAL;
647 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
648 goto out;
649 nh->nh_scope = res.scope;
650 nh->nh_oif = FIB_RES_OIF(res);
651 nh->nh_dev = dev = FIB_RES_DEV(res);
652 if (!dev)
653 goto out;
654 dev_hold(dev);
655 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
656 } else {
657 struct in_device *in_dev;
658
659 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
660 return -EINVAL;
661
662 rcu_read_lock();
663 err = -ENODEV;
664 in_dev = inetdev_by_index(net, nh->nh_oif);
665 if (in_dev == NULL)
666 goto out;
667 err = -ENETDOWN;
668 if (!(in_dev->dev->flags & IFF_UP))
669 goto out;
670 nh->nh_dev = in_dev->dev;
671 dev_hold(nh->nh_dev);
672 nh->nh_scope = RT_SCOPE_HOST;
673 err = 0;
674 }
675 out:
676 rcu_read_unlock();
677 return err;
678 }
679
680 static inline unsigned int fib_laddr_hashfn(__be32 val)
681 {
682 unsigned int mask = (fib_info_hash_size - 1);
683
684 return ((__force u32)val ^
685 ((__force u32)val >> 7) ^
686 ((__force u32)val >> 14)) & mask;
687 }
688
689 static struct hlist_head *fib_info_hash_alloc(int bytes)
690 {
691 if (bytes <= PAGE_SIZE)
692 return kzalloc(bytes, GFP_KERNEL);
693 else
694 return (struct hlist_head *)
695 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
696 get_order(bytes));
697 }
698
699 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
700 {
701 if (!hash)
702 return;
703
704 if (bytes <= PAGE_SIZE)
705 kfree(hash);
706 else
707 free_pages((unsigned long) hash, get_order(bytes));
708 }
709
710 static void fib_info_hash_move(struct hlist_head *new_info_hash,
711 struct hlist_head *new_laddrhash,
712 unsigned int new_size)
713 {
714 struct hlist_head *old_info_hash, *old_laddrhash;
715 unsigned int old_size = fib_info_hash_size;
716 unsigned int i, bytes;
717
718 spin_lock_bh(&fib_info_lock);
719 old_info_hash = fib_info_hash;
720 old_laddrhash = fib_info_laddrhash;
721 fib_info_hash_size = new_size;
722
723 for (i = 0; i < old_size; i++) {
724 struct hlist_head *head = &fib_info_hash[i];
725 struct hlist_node *n;
726 struct fib_info *fi;
727
728 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
729 struct hlist_head *dest;
730 unsigned int new_hash;
731
732 hlist_del(&fi->fib_hash);
733
734 new_hash = fib_info_hashfn(fi);
735 dest = &new_info_hash[new_hash];
736 hlist_add_head(&fi->fib_hash, dest);
737 }
738 }
739 fib_info_hash = new_info_hash;
740
741 for (i = 0; i < old_size; i++) {
742 struct hlist_head *lhead = &fib_info_laddrhash[i];
743 struct hlist_node *n;
744 struct fib_info *fi;
745
746 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
747 struct hlist_head *ldest;
748 unsigned int new_hash;
749
750 hlist_del(&fi->fib_lhash);
751
752 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
753 ldest = &new_laddrhash[new_hash];
754 hlist_add_head(&fi->fib_lhash, ldest);
755 }
756 }
757 fib_info_laddrhash = new_laddrhash;
758
759 spin_unlock_bh(&fib_info_lock);
760
761 bytes = old_size * sizeof(struct hlist_head *);
762 fib_info_hash_free(old_info_hash, bytes);
763 fib_info_hash_free(old_laddrhash, bytes);
764 }
765
766 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
767 {
768 nh->nh_saddr = inet_select_addr(nh->nh_dev,
769 nh->nh_gw,
770 nh->nh_parent->fib_scope);
771 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
772
773 return nh->nh_saddr;
774 }
775
776 struct fib_info *fib_create_info(struct fib_config *cfg)
777 {
778 int err;
779 struct fib_info *fi = NULL;
780 struct fib_info *ofi;
781 int nhs = 1;
782 struct net *net = cfg->fc_nlinfo.nl_net;
783
784 if (cfg->fc_type > RTN_MAX)
785 goto err_inval;
786
787 /* Fast check to catch the most weird cases */
788 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
789 goto err_inval;
790
791 #ifdef CONFIG_IP_ROUTE_MULTIPATH
792 if (cfg->fc_mp) {
793 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
794 if (nhs == 0)
795 goto err_inval;
796 }
797 #endif
798
799 err = -ENOBUFS;
800 if (fib_info_cnt >= fib_info_hash_size) {
801 unsigned int new_size = fib_info_hash_size << 1;
802 struct hlist_head *new_info_hash;
803 struct hlist_head *new_laddrhash;
804 unsigned int bytes;
805
806 if (!new_size)
807 new_size = 16;
808 bytes = new_size * sizeof(struct hlist_head *);
809 new_info_hash = fib_info_hash_alloc(bytes);
810 new_laddrhash = fib_info_hash_alloc(bytes);
811 if (!new_info_hash || !new_laddrhash) {
812 fib_info_hash_free(new_info_hash, bytes);
813 fib_info_hash_free(new_laddrhash, bytes);
814 } else
815 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
816
817 if (!fib_info_hash_size)
818 goto failure;
819 }
820
821 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
822 if (fi == NULL)
823 goto failure;
824 if (cfg->fc_mx) {
825 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
826 if (!fi->fib_metrics)
827 goto failure;
828 } else
829 fi->fib_metrics = (u32 *) dst_default_metrics;
830 fib_info_cnt++;
831
832 fi->fib_net = hold_net(net);
833 fi->fib_protocol = cfg->fc_protocol;
834 fi->fib_scope = cfg->fc_scope;
835 fi->fib_flags = cfg->fc_flags;
836 fi->fib_priority = cfg->fc_priority;
837 fi->fib_prefsrc = cfg->fc_prefsrc;
838 fi->fib_type = cfg->fc_type;
839
840 fi->fib_nhs = nhs;
841 change_nexthops(fi) {
842 nexthop_nh->nh_parent = fi;
843 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
844 if (!nexthop_nh->nh_pcpu_rth_output)
845 goto failure;
846 } endfor_nexthops(fi)
847
848 if (cfg->fc_mx) {
849 struct nlattr *nla;
850 int remaining;
851
852 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
853 int type = nla_type(nla);
854
855 if (type) {
856 u32 val;
857
858 if (type > RTAX_MAX)
859 goto err_inval;
860 val = nla_get_u32(nla);
861 if (type == RTAX_ADVMSS && val > 65535 - 40)
862 val = 65535 - 40;
863 if (type == RTAX_MTU && val > 65535 - 15)
864 val = 65535 - 15;
865 fi->fib_metrics[type - 1] = val;
866 }
867 }
868 }
869
870 if (cfg->fc_mp) {
871 #ifdef CONFIG_IP_ROUTE_MULTIPATH
872 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
873 if (err != 0)
874 goto failure;
875 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
876 goto err_inval;
877 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
878 goto err_inval;
879 #ifdef CONFIG_IP_ROUTE_CLASSID
880 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
881 goto err_inval;
882 #endif
883 #else
884 goto err_inval;
885 #endif
886 } else {
887 struct fib_nh *nh = fi->fib_nh;
888
889 nh->nh_oif = cfg->fc_oif;
890 nh->nh_gw = cfg->fc_gw;
891 nh->nh_flags = cfg->fc_flags;
892 #ifdef CONFIG_IP_ROUTE_CLASSID
893 nh->nh_tclassid = cfg->fc_flow;
894 if (nh->nh_tclassid)
895 fi->fib_net->ipv4.fib_num_tclassid_users++;
896 #endif
897 #ifdef CONFIG_IP_ROUTE_MULTIPATH
898 nh->nh_weight = 1;
899 #endif
900 }
901
902 if (fib_props[cfg->fc_type].error) {
903 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
904 goto err_inval;
905 goto link_it;
906 } else {
907 switch (cfg->fc_type) {
908 case RTN_UNICAST:
909 case RTN_LOCAL:
910 case RTN_BROADCAST:
911 case RTN_ANYCAST:
912 case RTN_MULTICAST:
913 break;
914 default:
915 goto err_inval;
916 }
917 }
918
919 if (cfg->fc_scope > RT_SCOPE_HOST)
920 goto err_inval;
921
922 if (cfg->fc_scope == RT_SCOPE_HOST) {
923 struct fib_nh *nh = fi->fib_nh;
924
925 /* Local address is added. */
926 if (nhs != 1 || nh->nh_gw)
927 goto err_inval;
928 nh->nh_scope = RT_SCOPE_NOWHERE;
929 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
930 err = -ENODEV;
931 if (nh->nh_dev == NULL)
932 goto failure;
933 } else {
934 change_nexthops(fi) {
935 err = fib_check_nh(cfg, fi, nexthop_nh);
936 if (err != 0)
937 goto failure;
938 } endfor_nexthops(fi)
939 }
940
941 if (fi->fib_prefsrc) {
942 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
943 fi->fib_prefsrc != cfg->fc_dst)
944 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
945 goto err_inval;
946 }
947
948 change_nexthops(fi) {
949 fib_info_update_nh_saddr(net, nexthop_nh);
950 } endfor_nexthops(fi)
951
952 link_it:
953 ofi = fib_find_info(fi);
954 if (ofi) {
955 fi->fib_dead = 1;
956 free_fib_info(fi);
957 ofi->fib_treeref++;
958 return ofi;
959 }
960
961 fi->fib_treeref++;
962 atomic_inc(&fi->fib_clntref);
963 spin_lock_bh(&fib_info_lock);
964 hlist_add_head(&fi->fib_hash,
965 &fib_info_hash[fib_info_hashfn(fi)]);
966 if (fi->fib_prefsrc) {
967 struct hlist_head *head;
968
969 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
970 hlist_add_head(&fi->fib_lhash, head);
971 }
972 change_nexthops(fi) {
973 struct hlist_head *head;
974 unsigned int hash;
975
976 if (!nexthop_nh->nh_dev)
977 continue;
978 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
979 head = &fib_info_devhash[hash];
980 hlist_add_head(&nexthop_nh->nh_hash, head);
981 } endfor_nexthops(fi)
982 spin_unlock_bh(&fib_info_lock);
983 return fi;
984
985 err_inval:
986 err = -EINVAL;
987
988 failure:
989 if (fi) {
990 fi->fib_dead = 1;
991 free_fib_info(fi);
992 }
993
994 return ERR_PTR(err);
995 }
996
997 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
998 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
999 struct fib_info *fi, unsigned int flags)
1000 {
1001 struct nlmsghdr *nlh;
1002 struct rtmsg *rtm;
1003
1004 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1005 if (nlh == NULL)
1006 return -EMSGSIZE;
1007
1008 rtm = nlmsg_data(nlh);
1009 rtm->rtm_family = AF_INET;
1010 rtm->rtm_dst_len = dst_len;
1011 rtm->rtm_src_len = 0;
1012 rtm->rtm_tos = tos;
1013 if (tb_id < 256)
1014 rtm->rtm_table = tb_id;
1015 else
1016 rtm->rtm_table = RT_TABLE_COMPAT;
1017 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1018 goto nla_put_failure;
1019 rtm->rtm_type = type;
1020 rtm->rtm_flags = fi->fib_flags;
1021 rtm->rtm_scope = fi->fib_scope;
1022 rtm->rtm_protocol = fi->fib_protocol;
1023
1024 if (rtm->rtm_dst_len &&
1025 nla_put_be32(skb, RTA_DST, dst))
1026 goto nla_put_failure;
1027 if (fi->fib_priority &&
1028 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1029 goto nla_put_failure;
1030 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1031 goto nla_put_failure;
1032
1033 if (fi->fib_prefsrc &&
1034 nla_put_be32(skb, RTA_PREFSRC, fi->fib_prefsrc))
1035 goto nla_put_failure;
1036 if (fi->fib_nhs == 1) {
1037 if (fi->fib_nh->nh_gw &&
1038 nla_put_be32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1039 goto nla_put_failure;
1040 if (fi->fib_nh->nh_oif &&
1041 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1042 goto nla_put_failure;
1043 #ifdef CONFIG_IP_ROUTE_CLASSID
1044 if (fi->fib_nh[0].nh_tclassid &&
1045 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1046 goto nla_put_failure;
1047 #endif
1048 }
1049 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1050 if (fi->fib_nhs > 1) {
1051 struct rtnexthop *rtnh;
1052 struct nlattr *mp;
1053
1054 mp = nla_nest_start(skb, RTA_MULTIPATH);
1055 if (mp == NULL)
1056 goto nla_put_failure;
1057
1058 for_nexthops(fi) {
1059 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1060 if (rtnh == NULL)
1061 goto nla_put_failure;
1062
1063 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1064 rtnh->rtnh_hops = nh->nh_weight - 1;
1065 rtnh->rtnh_ifindex = nh->nh_oif;
1066
1067 if (nh->nh_gw &&
1068 nla_put_be32(skb, RTA_GATEWAY, nh->nh_gw))
1069 goto nla_put_failure;
1070 #ifdef CONFIG_IP_ROUTE_CLASSID
1071 if (nh->nh_tclassid &&
1072 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1073 goto nla_put_failure;
1074 #endif
1075 /* length of rtnetlink header + attributes */
1076 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1077 } endfor_nexthops(fi);
1078
1079 nla_nest_end(skb, mp);
1080 }
1081 #endif
1082 return nlmsg_end(skb, nlh);
1083
1084 nla_put_failure:
1085 nlmsg_cancel(skb, nlh);
1086 return -EMSGSIZE;
1087 }
1088
1089 /*
1090 * Update FIB if:
1091 * - local address disappeared -> we must delete all the entries
1092 * referring to it.
1093 * - device went down -> we must shutdown all nexthops going via it.
1094 */
1095 int fib_sync_down_addr(struct net *net, __be32 local)
1096 {
1097 int ret = 0;
1098 unsigned int hash = fib_laddr_hashfn(local);
1099 struct hlist_head *head = &fib_info_laddrhash[hash];
1100 struct fib_info *fi;
1101
1102 if (fib_info_laddrhash == NULL || local == 0)
1103 return 0;
1104
1105 hlist_for_each_entry(fi, head, fib_lhash) {
1106 if (!net_eq(fi->fib_net, net))
1107 continue;
1108 if (fi->fib_prefsrc == local) {
1109 fi->fib_flags |= RTNH_F_DEAD;
1110 ret++;
1111 }
1112 }
1113 return ret;
1114 }
1115
1116 int fib_sync_down_dev(struct net_device *dev, int force)
1117 {
1118 int ret = 0;
1119 int scope = RT_SCOPE_NOWHERE;
1120 struct fib_info *prev_fi = NULL;
1121 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1122 struct hlist_head *head = &fib_info_devhash[hash];
1123 struct fib_nh *nh;
1124
1125 if (force)
1126 scope = -1;
1127
1128 hlist_for_each_entry(nh, head, nh_hash) {
1129 struct fib_info *fi = nh->nh_parent;
1130 int dead;
1131
1132 BUG_ON(!fi->fib_nhs);
1133 if (nh->nh_dev != dev || fi == prev_fi)
1134 continue;
1135 prev_fi = fi;
1136 dead = 0;
1137 change_nexthops(fi) {
1138 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1139 dead++;
1140 else if (nexthop_nh->nh_dev == dev &&
1141 nexthop_nh->nh_scope != scope) {
1142 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1143 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1144 spin_lock_bh(&fib_multipath_lock);
1145 fi->fib_power -= nexthop_nh->nh_power;
1146 nexthop_nh->nh_power = 0;
1147 spin_unlock_bh(&fib_multipath_lock);
1148 #endif
1149 dead++;
1150 }
1151 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1152 if (force > 1 && nexthop_nh->nh_dev == dev) {
1153 dead = fi->fib_nhs;
1154 break;
1155 }
1156 #endif
1157 } endfor_nexthops(fi)
1158 if (dead == fi->fib_nhs) {
1159 fi->fib_flags |= RTNH_F_DEAD;
1160 ret++;
1161 }
1162 }
1163
1164 return ret;
1165 }
1166
1167 /* Must be invoked inside of an RCU protected region. */
1168 void fib_select_default(struct fib_result *res)
1169 {
1170 struct fib_info *fi = NULL, *last_resort = NULL;
1171 struct list_head *fa_head = res->fa_head;
1172 struct fib_table *tb = res->table;
1173 int order = -1, last_idx = -1;
1174 struct fib_alias *fa;
1175
1176 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1177 struct fib_info *next_fi = fa->fa_info;
1178
1179 if (next_fi->fib_scope != res->scope ||
1180 fa->fa_type != RTN_UNICAST)
1181 continue;
1182
1183 if (next_fi->fib_priority > res->fi->fib_priority)
1184 break;
1185 if (!next_fi->fib_nh[0].nh_gw ||
1186 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1187 continue;
1188
1189 fib_alias_accessed(fa);
1190
1191 if (fi == NULL) {
1192 if (next_fi != res->fi)
1193 break;
1194 } else if (!fib_detect_death(fi, order, &last_resort,
1195 &last_idx, tb->tb_default)) {
1196 fib_result_assign(res, fi);
1197 tb->tb_default = order;
1198 goto out;
1199 }
1200 fi = next_fi;
1201 order++;
1202 }
1203
1204 if (order <= 0 || fi == NULL) {
1205 tb->tb_default = -1;
1206 goto out;
1207 }
1208
1209 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1210 tb->tb_default)) {
1211 fib_result_assign(res, fi);
1212 tb->tb_default = order;
1213 goto out;
1214 }
1215
1216 if (last_idx >= 0)
1217 fib_result_assign(res, last_resort);
1218 tb->tb_default = last_idx;
1219 out:
1220 return;
1221 }
1222
1223 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1224
1225 /*
1226 * Dead device goes up. We wake up dead nexthops.
1227 * It takes sense only on multipath routes.
1228 */
1229 int fib_sync_up(struct net_device *dev)
1230 {
1231 struct fib_info *prev_fi;
1232 unsigned int hash;
1233 struct hlist_head *head;
1234 struct fib_nh *nh;
1235 int ret;
1236
1237 if (!(dev->flags & IFF_UP))
1238 return 0;
1239
1240 prev_fi = NULL;
1241 hash = fib_devindex_hashfn(dev->ifindex);
1242 head = &fib_info_devhash[hash];
1243 ret = 0;
1244
1245 hlist_for_each_entry(nh, head, nh_hash) {
1246 struct fib_info *fi = nh->nh_parent;
1247 int alive;
1248
1249 BUG_ON(!fi->fib_nhs);
1250 if (nh->nh_dev != dev || fi == prev_fi)
1251 continue;
1252
1253 prev_fi = fi;
1254 alive = 0;
1255 change_nexthops(fi) {
1256 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1257 alive++;
1258 continue;
1259 }
1260 if (nexthop_nh->nh_dev == NULL ||
1261 !(nexthop_nh->nh_dev->flags & IFF_UP))
1262 continue;
1263 if (nexthop_nh->nh_dev != dev ||
1264 !__in_dev_get_rtnl(dev))
1265 continue;
1266 alive++;
1267 spin_lock_bh(&fib_multipath_lock);
1268 nexthop_nh->nh_power = 0;
1269 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1270 spin_unlock_bh(&fib_multipath_lock);
1271 } endfor_nexthops(fi)
1272
1273 if (alive > 0) {
1274 fi->fib_flags &= ~RTNH_F_DEAD;
1275 ret++;
1276 }
1277 }
1278
1279 return ret;
1280 }
1281
1282 /*
1283 * The algorithm is suboptimal, but it provides really
1284 * fair weighted route distribution.
1285 */
1286 void fib_select_multipath(struct fib_result *res)
1287 {
1288 struct fib_info *fi = res->fi;
1289 int w;
1290
1291 spin_lock_bh(&fib_multipath_lock);
1292 if (fi->fib_power <= 0) {
1293 int power = 0;
1294 change_nexthops(fi) {
1295 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1296 power += nexthop_nh->nh_weight;
1297 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1298 }
1299 } endfor_nexthops(fi);
1300 fi->fib_power = power;
1301 if (power <= 0) {
1302 spin_unlock_bh(&fib_multipath_lock);
1303 /* Race condition: route has just become dead. */
1304 res->nh_sel = 0;
1305 return;
1306 }
1307 }
1308
1309
1310 /* w should be random number [0..fi->fib_power-1],
1311 * it is pretty bad approximation.
1312 */
1313
1314 w = jiffies % fi->fib_power;
1315
1316 change_nexthops(fi) {
1317 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1318 nexthop_nh->nh_power) {
1319 w -= nexthop_nh->nh_power;
1320 if (w <= 0) {
1321 nexthop_nh->nh_power--;
1322 fi->fib_power--;
1323 res->nh_sel = nhsel;
1324 spin_unlock_bh(&fib_multipath_lock);
1325 return;
1326 }
1327 }
1328 } endfor_nexthops(fi);
1329
1330 /* Race condition: route has just become dead. */
1331 res->nh_sel = 0;
1332 spin_unlock_bh(&fib_multipath_lock);
1333 }
1334 #endif
Linux kernel - Deliverables
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