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Merge git://git.infradead.org/users/willy/linux-nvme
[GitHub/mt8127/android_kernel_alcatel_ttab.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);
173
174 kfree(fnhe);
175
176 fnhe = next;
177 }
178 }
179 kfree(hash);
180 }
181
182 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
183 {
184 int cpu;
185
186 if (!rtp)
187 return;
188
189 for_each_possible_cpu(cpu) {
190 struct rtable *rt;
191
192 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
193 if (rt)
194 dst_free(&rt->dst);
195 }
196 free_percpu(rtp);
197 }
198
199 /* Release a nexthop info record */
200 static void free_fib_info_rcu(struct rcu_head *head)
201 {
202 struct fib_info *fi = container_of(head, struct fib_info, rcu);
203
204 change_nexthops(fi) {
205 if (nexthop_nh->nh_dev)
206 dev_put(nexthop_nh->nh_dev);
207 if (nexthop_nh->nh_exceptions)
208 free_nh_exceptions(nexthop_nh);
209 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
210 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
211 } endfor_nexthops(fi);
212
213 release_net(fi->fib_net);
214 if (fi->fib_metrics != (u32 *) dst_default_metrics)
215 kfree(fi->fib_metrics);
216 kfree(fi);
217 }
218
219 void free_fib_info(struct fib_info *fi)
220 {
221 if (fi->fib_dead == 0) {
222 pr_warn("Freeing alive fib_info %p\n", fi);
223 return;
224 }
225 fib_info_cnt--;
226 #ifdef CONFIG_IP_ROUTE_CLASSID
227 change_nexthops(fi) {
228 if (nexthop_nh->nh_tclassid)
229 fi->fib_net->ipv4.fib_num_tclassid_users--;
230 } endfor_nexthops(fi);
231 #endif
232 call_rcu(&fi->rcu, free_fib_info_rcu);
233 }
234
235 void fib_release_info(struct fib_info *fi)
236 {
237 spin_lock_bh(&fib_info_lock);
238 if (fi && --fi->fib_treeref == 0) {
239 hlist_del(&fi->fib_hash);
240 if (fi->fib_prefsrc)
241 hlist_del(&fi->fib_lhash);
242 change_nexthops(fi) {
243 if (!nexthop_nh->nh_dev)
244 continue;
245 hlist_del(&nexthop_nh->nh_hash);
246 } endfor_nexthops(fi)
247 fi->fib_dead = 1;
248 fib_info_put(fi);
249 }
250 spin_unlock_bh(&fib_info_lock);
251 }
252
253 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
254 {
255 const struct fib_nh *onh = ofi->fib_nh;
256
257 for_nexthops(fi) {
258 if (nh->nh_oif != onh->nh_oif ||
259 nh->nh_gw != onh->nh_gw ||
260 nh->nh_scope != onh->nh_scope ||
261 #ifdef CONFIG_IP_ROUTE_MULTIPATH
262 nh->nh_weight != onh->nh_weight ||
263 #endif
264 #ifdef CONFIG_IP_ROUTE_CLASSID
265 nh->nh_tclassid != onh->nh_tclassid ||
266 #endif
267 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
268 return -1;
269 onh++;
270 } endfor_nexthops(fi);
271 return 0;
272 }
273
274 static inline unsigned int fib_devindex_hashfn(unsigned int val)
275 {
276 unsigned int mask = DEVINDEX_HASHSIZE - 1;
277
278 return (val ^
279 (val >> DEVINDEX_HASHBITS) ^
280 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
281 }
282
283 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
284 {
285 unsigned int mask = (fib_info_hash_size - 1);
286 unsigned int val = fi->fib_nhs;
287
288 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
289 val ^= (__force u32)fi->fib_prefsrc;
290 val ^= fi->fib_priority;
291 for_nexthops(fi) {
292 val ^= fib_devindex_hashfn(nh->nh_oif);
293 } endfor_nexthops(fi)
294
295 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
296 }
297
298 static struct fib_info *fib_find_info(const struct fib_info *nfi)
299 {
300 struct hlist_head *head;
301 struct fib_info *fi;
302 unsigned int hash;
303
304 hash = fib_info_hashfn(nfi);
305 head = &fib_info_hash[hash];
306
307 hlist_for_each_entry(fi, head, fib_hash) {
308 if (!net_eq(fi->fib_net, nfi->fib_net))
309 continue;
310 if (fi->fib_nhs != nfi->fib_nhs)
311 continue;
312 if (nfi->fib_protocol == fi->fib_protocol &&
313 nfi->fib_scope == fi->fib_scope &&
314 nfi->fib_prefsrc == fi->fib_prefsrc &&
315 nfi->fib_priority == fi->fib_priority &&
316 nfi->fib_type == fi->fib_type &&
317 memcmp(nfi->fib_metrics, fi->fib_metrics,
318 sizeof(u32) * RTAX_MAX) == 0 &&
319 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
320 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
321 return fi;
322 }
323
324 return NULL;
325 }
326
327 /* Check, that the gateway is already configured.
328 * Used only by redirect accept routine.
329 */
330 int ip_fib_check_default(__be32 gw, struct net_device *dev)
331 {
332 struct hlist_head *head;
333 struct fib_nh *nh;
334 unsigned int hash;
335
336 spin_lock(&fib_info_lock);
337
338 hash = fib_devindex_hashfn(dev->ifindex);
339 head = &fib_info_devhash[hash];
340 hlist_for_each_entry(nh, head, nh_hash) {
341 if (nh->nh_dev == dev &&
342 nh->nh_gw == gw &&
343 !(nh->nh_flags & RTNH_F_DEAD)) {
344 spin_unlock(&fib_info_lock);
345 return 0;
346 }
347 }
348
349 spin_unlock(&fib_info_lock);
350
351 return -1;
352 }
353
354 static inline size_t fib_nlmsg_size(struct fib_info *fi)
355 {
356 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
357 + nla_total_size(4) /* RTA_TABLE */
358 + nla_total_size(4) /* RTA_DST */
359 + nla_total_size(4) /* RTA_PRIORITY */
360 + nla_total_size(4); /* RTA_PREFSRC */
361
362 /* space for nested metrics */
363 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
364
365 if (fi->fib_nhs) {
366 /* Also handles the special case fib_nhs == 1 */
367
368 /* each nexthop is packed in an attribute */
369 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
370
371 /* may contain flow and gateway attribute */
372 nhsize += 2 * nla_total_size(4);
373
374 /* all nexthops are packed in a nested attribute */
375 payload += nla_total_size(fi->fib_nhs * nhsize);
376 }
377
378 return payload;
379 }
380
381 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
382 int dst_len, u32 tb_id, struct nl_info *info,
383 unsigned int nlm_flags)
384 {
385 struct sk_buff *skb;
386 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
387 int err = -ENOBUFS;
388
389 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
390 if (skb == NULL)
391 goto errout;
392
393 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
394 fa->fa_type, key, dst_len,
395 fa->fa_tos, fa->fa_info, nlm_flags);
396 if (err < 0) {
397 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
398 WARN_ON(err == -EMSGSIZE);
399 kfree_skb(skb);
400 goto errout;
401 }
402 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
403 info->nlh, GFP_KERNEL);
404 return;
405 errout:
406 if (err < 0)
407 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
408 }
409
410 /* Return the first fib alias matching TOS with
411 * priority less than or equal to PRIO.
412 */
413 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
414 {
415 if (fah) {
416 struct fib_alias *fa;
417 list_for_each_entry(fa, fah, fa_list) {
418 if (fa->fa_tos > tos)
419 continue;
420 if (fa->fa_info->fib_priority >= prio ||
421 fa->fa_tos < tos)
422 return fa;
423 }
424 }
425 return NULL;
426 }
427
428 int fib_detect_death(struct fib_info *fi, int order,
429 struct fib_info **last_resort, int *last_idx, int dflt)
430 {
431 struct neighbour *n;
432 int state = NUD_NONE;
433
434 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
435 if (n) {
436 state = n->nud_state;
437 neigh_release(n);
438 }
439 if (state == NUD_REACHABLE)
440 return 0;
441 if ((state & NUD_VALID) && order != dflt)
442 return 0;
443 if ((state & NUD_VALID) ||
444 (*last_idx < 0 && order > dflt)) {
445 *last_resort = fi;
446 *last_idx = order;
447 }
448 return 1;
449 }
450
451 #ifdef CONFIG_IP_ROUTE_MULTIPATH
452
453 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
454 {
455 int nhs = 0;
456
457 while (rtnh_ok(rtnh, remaining)) {
458 nhs++;
459 rtnh = rtnh_next(rtnh, &remaining);
460 }
461
462 /* leftover implies invalid nexthop configuration, discard it */
463 return remaining > 0 ? 0 : nhs;
464 }
465
466 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
467 int remaining, struct fib_config *cfg)
468 {
469 change_nexthops(fi) {
470 int attrlen;
471
472 if (!rtnh_ok(rtnh, remaining))
473 return -EINVAL;
474
475 nexthop_nh->nh_flags =
476 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
477 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
478 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
479
480 attrlen = rtnh_attrlen(rtnh);
481 if (attrlen > 0) {
482 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
483
484 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
485 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
486 #ifdef CONFIG_IP_ROUTE_CLASSID
487 nla = nla_find(attrs, attrlen, RTA_FLOW);
488 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
489 if (nexthop_nh->nh_tclassid)
490 fi->fib_net->ipv4.fib_num_tclassid_users++;
491 #endif
492 }
493
494 rtnh = rtnh_next(rtnh, &remaining);
495 } endfor_nexthops(fi);
496
497 return 0;
498 }
499
500 #endif
501
502 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
503 {
504 #ifdef CONFIG_IP_ROUTE_MULTIPATH
505 struct rtnexthop *rtnh;
506 int remaining;
507 #endif
508
509 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
510 return 1;
511
512 if (cfg->fc_oif || cfg->fc_gw) {
513 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
514 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
515 return 0;
516 return 1;
517 }
518
519 #ifdef CONFIG_IP_ROUTE_MULTIPATH
520 if (cfg->fc_mp == NULL)
521 return 0;
522
523 rtnh = cfg->fc_mp;
524 remaining = cfg->fc_mp_len;
525
526 for_nexthops(fi) {
527 int attrlen;
528
529 if (!rtnh_ok(rtnh, remaining))
530 return -EINVAL;
531
532 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
533 return 1;
534
535 attrlen = rtnh_attrlen(rtnh);
536 if (attrlen < 0) {
537 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
538
539 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
540 if (nla && nla_get_be32(nla) != nh->nh_gw)
541 return 1;
542 #ifdef CONFIG_IP_ROUTE_CLASSID
543 nla = nla_find(attrs, attrlen, RTA_FLOW);
544 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
545 return 1;
546 #endif
547 }
548
549 rtnh = rtnh_next(rtnh, &remaining);
550 } endfor_nexthops(fi);
551 #endif
552 return 0;
553 }
554
555
556 /*
557 * Picture
558 * -------
559 *
560 * Semantics of nexthop is very messy by historical reasons.
561 * We have to take into account, that:
562 * a) gateway can be actually local interface address,
563 * so that gatewayed route is direct.
564 * b) gateway must be on-link address, possibly
565 * described not by an ifaddr, but also by a direct route.
566 * c) If both gateway and interface are specified, they should not
567 * contradict.
568 * d) If we use tunnel routes, gateway could be not on-link.
569 *
570 * Attempt to reconcile all of these (alas, self-contradictory) conditions
571 * results in pretty ugly and hairy code with obscure logic.
572 *
573 * I chose to generalized it instead, so that the size
574 * of code does not increase practically, but it becomes
575 * much more general.
576 * Every prefix is assigned a "scope" value: "host" is local address,
577 * "link" is direct route,
578 * [ ... "site" ... "interior" ... ]
579 * and "universe" is true gateway route with global meaning.
580 *
581 * Every prefix refers to a set of "nexthop"s (gw, oif),
582 * where gw must have narrower scope. This recursion stops
583 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
584 * which means that gw is forced to be on link.
585 *
586 * Code is still hairy, but now it is apparently logically
587 * consistent and very flexible. F.e. as by-product it allows
588 * to co-exists in peace independent exterior and interior
589 * routing processes.
590 *
591 * Normally it looks as following.
592 *
593 * {universe prefix} -> (gw, oif) [scope link]
594 * |
595 * |-> {link prefix} -> (gw, oif) [scope local]
596 * |
597 * |-> {local prefix} (terminal node)
598 */
599 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
600 struct fib_nh *nh)
601 {
602 int err;
603 struct net *net;
604 struct net_device *dev;
605
606 net = cfg->fc_nlinfo.nl_net;
607 if (nh->nh_gw) {
608 struct fib_result res;
609
610 if (nh->nh_flags & RTNH_F_ONLINK) {
611
612 if (cfg->fc_scope >= RT_SCOPE_LINK)
613 return -EINVAL;
614 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
615 return -EINVAL;
616 dev = __dev_get_by_index(net, nh->nh_oif);
617 if (!dev)
618 return -ENODEV;
619 if (!(dev->flags & IFF_UP))
620 return -ENETDOWN;
621 nh->nh_dev = dev;
622 dev_hold(dev);
623 nh->nh_scope = RT_SCOPE_LINK;
624 return 0;
625 }
626 rcu_read_lock();
627 {
628 struct flowi4 fl4 = {
629 .daddr = nh->nh_gw,
630 .flowi4_scope = cfg->fc_scope + 1,
631 .flowi4_oif = nh->nh_oif,
632 };
633
634 /* It is not necessary, but requires a bit of thinking */
635 if (fl4.flowi4_scope < RT_SCOPE_LINK)
636 fl4.flowi4_scope = RT_SCOPE_LINK;
637 err = fib_lookup(net, &fl4, &res);
638 if (err) {
639 rcu_read_unlock();
640 return err;
641 }
642 }
643 err = -EINVAL;
644 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
645 goto out;
646 nh->nh_scope = res.scope;
647 nh->nh_oif = FIB_RES_OIF(res);
648 nh->nh_dev = dev = FIB_RES_DEV(res);
649 if (!dev)
650 goto out;
651 dev_hold(dev);
652 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
653 } else {
654 struct in_device *in_dev;
655
656 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
657 return -EINVAL;
658
659 rcu_read_lock();
660 err = -ENODEV;
661 in_dev = inetdev_by_index(net, nh->nh_oif);
662 if (in_dev == NULL)
663 goto out;
664 err = -ENETDOWN;
665 if (!(in_dev->dev->flags & IFF_UP))
666 goto out;
667 nh->nh_dev = in_dev->dev;
668 dev_hold(nh->nh_dev);
669 nh->nh_scope = RT_SCOPE_HOST;
670 err = 0;
671 }
672 out:
673 rcu_read_unlock();
674 return err;
675 }
676
677 static inline unsigned int fib_laddr_hashfn(__be32 val)
678 {
679 unsigned int mask = (fib_info_hash_size - 1);
680
681 return ((__force u32)val ^
682 ((__force u32)val >> 7) ^
683 ((__force u32)val >> 14)) & mask;
684 }
685
686 static struct hlist_head *fib_info_hash_alloc(int bytes)
687 {
688 if (bytes <= PAGE_SIZE)
689 return kzalloc(bytes, GFP_KERNEL);
690 else
691 return (struct hlist_head *)
692 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
693 get_order(bytes));
694 }
695
696 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
697 {
698 if (!hash)
699 return;
700
701 if (bytes <= PAGE_SIZE)
702 kfree(hash);
703 else
704 free_pages((unsigned long) hash, get_order(bytes));
705 }
706
707 static void fib_info_hash_move(struct hlist_head *new_info_hash,
708 struct hlist_head *new_laddrhash,
709 unsigned int new_size)
710 {
711 struct hlist_head *old_info_hash, *old_laddrhash;
712 unsigned int old_size = fib_info_hash_size;
713 unsigned int i, bytes;
714
715 spin_lock_bh(&fib_info_lock);
716 old_info_hash = fib_info_hash;
717 old_laddrhash = fib_info_laddrhash;
718 fib_info_hash_size = new_size;
719
720 for (i = 0; i < old_size; i++) {
721 struct hlist_head *head = &fib_info_hash[i];
722 struct hlist_node *n;
723 struct fib_info *fi;
724
725 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
726 struct hlist_head *dest;
727 unsigned int new_hash;
728
729 hlist_del(&fi->fib_hash);
730
731 new_hash = fib_info_hashfn(fi);
732 dest = &new_info_hash[new_hash];
733 hlist_add_head(&fi->fib_hash, dest);
734 }
735 }
736 fib_info_hash = new_info_hash;
737
738 for (i = 0; i < old_size; i++) {
739 struct hlist_head *lhead = &fib_info_laddrhash[i];
740 struct hlist_node *n;
741 struct fib_info *fi;
742
743 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
744 struct hlist_head *ldest;
745 unsigned int new_hash;
746
747 hlist_del(&fi->fib_lhash);
748
749 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
750 ldest = &new_laddrhash[new_hash];
751 hlist_add_head(&fi->fib_lhash, ldest);
752 }
753 }
754 fib_info_laddrhash = new_laddrhash;
755
756 spin_unlock_bh(&fib_info_lock);
757
758 bytes = old_size * sizeof(struct hlist_head *);
759 fib_info_hash_free(old_info_hash, bytes);
760 fib_info_hash_free(old_laddrhash, bytes);
761 }
762
763 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
764 {
765 nh->nh_saddr = inet_select_addr(nh->nh_dev,
766 nh->nh_gw,
767 nh->nh_parent->fib_scope);
768 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
769
770 return nh->nh_saddr;
771 }
772
773 struct fib_info *fib_create_info(struct fib_config *cfg)
774 {
775 int err;
776 struct fib_info *fi = NULL;
777 struct fib_info *ofi;
778 int nhs = 1;
779 struct net *net = cfg->fc_nlinfo.nl_net;
780
781 if (cfg->fc_type > RTN_MAX)
782 goto err_inval;
783
784 /* Fast check to catch the most weird cases */
785 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
786 goto err_inval;
787
788 #ifdef CONFIG_IP_ROUTE_MULTIPATH
789 if (cfg->fc_mp) {
790 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
791 if (nhs == 0)
792 goto err_inval;
793 }
794 #endif
795
796 err = -ENOBUFS;
797 if (fib_info_cnt >= fib_info_hash_size) {
798 unsigned int new_size = fib_info_hash_size << 1;
799 struct hlist_head *new_info_hash;
800 struct hlist_head *new_laddrhash;
801 unsigned int bytes;
802
803 if (!new_size)
804 new_size = 16;
805 bytes = new_size * sizeof(struct hlist_head *);
806 new_info_hash = fib_info_hash_alloc(bytes);
807 new_laddrhash = fib_info_hash_alloc(bytes);
808 if (!new_info_hash || !new_laddrhash) {
809 fib_info_hash_free(new_info_hash, bytes);
810 fib_info_hash_free(new_laddrhash, bytes);
811 } else
812 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
813
814 if (!fib_info_hash_size)
815 goto failure;
816 }
817
818 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
819 if (fi == NULL)
820 goto failure;
821 if (cfg->fc_mx) {
822 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
823 if (!fi->fib_metrics)
824 goto failure;
825 } else
826 fi->fib_metrics = (u32 *) dst_default_metrics;
827 fib_info_cnt++;
828
829 fi->fib_net = hold_net(net);
830 fi->fib_protocol = cfg->fc_protocol;
831 fi->fib_scope = cfg->fc_scope;
832 fi->fib_flags = cfg->fc_flags;
833 fi->fib_priority = cfg->fc_priority;
834 fi->fib_prefsrc = cfg->fc_prefsrc;
835 fi->fib_type = cfg->fc_type;
836
837 fi->fib_nhs = nhs;
838 change_nexthops(fi) {
839 nexthop_nh->nh_parent = fi;
840 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
841 if (!nexthop_nh->nh_pcpu_rth_output)
842 goto failure;
843 } endfor_nexthops(fi)
844
845 if (cfg->fc_mx) {
846 struct nlattr *nla;
847 int remaining;
848
849 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
850 int type = nla_type(nla);
851
852 if (type) {
853 u32 val;
854
855 if (type > RTAX_MAX)
856 goto err_inval;
857 val = nla_get_u32(nla);
858 if (type == RTAX_ADVMSS && val > 65535 - 40)
859 val = 65535 - 40;
860 if (type == RTAX_MTU && val > 65535 - 15)
861 val = 65535 - 15;
862 fi->fib_metrics[type - 1] = val;
863 }
864 }
865 }
866
867 if (cfg->fc_mp) {
868 #ifdef CONFIG_IP_ROUTE_MULTIPATH
869 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
870 if (err != 0)
871 goto failure;
872 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
873 goto err_inval;
874 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
875 goto err_inval;
876 #ifdef CONFIG_IP_ROUTE_CLASSID
877 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
878 goto err_inval;
879 #endif
880 #else
881 goto err_inval;
882 #endif
883 } else {
884 struct fib_nh *nh = fi->fib_nh;
885
886 nh->nh_oif = cfg->fc_oif;
887 nh->nh_gw = cfg->fc_gw;
888 nh->nh_flags = cfg->fc_flags;
889 #ifdef CONFIG_IP_ROUTE_CLASSID
890 nh->nh_tclassid = cfg->fc_flow;
891 if (nh->nh_tclassid)
892 fi->fib_net->ipv4.fib_num_tclassid_users++;
893 #endif
894 #ifdef CONFIG_IP_ROUTE_MULTIPATH
895 nh->nh_weight = 1;
896 #endif
897 }
898
899 if (fib_props[cfg->fc_type].error) {
900 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
901 goto err_inval;
902 goto link_it;
903 } else {
904 switch (cfg->fc_type) {
905 case RTN_UNICAST:
906 case RTN_LOCAL:
907 case RTN_BROADCAST:
908 case RTN_ANYCAST:
909 case RTN_MULTICAST:
910 break;
911 default:
912 goto err_inval;
913 }
914 }
915
916 if (cfg->fc_scope > RT_SCOPE_HOST)
917 goto err_inval;
918
919 if (cfg->fc_scope == RT_SCOPE_HOST) {
920 struct fib_nh *nh = fi->fib_nh;
921
922 /* Local address is added. */
923 if (nhs != 1 || nh->nh_gw)
924 goto err_inval;
925 nh->nh_scope = RT_SCOPE_NOWHERE;
926 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
927 err = -ENODEV;
928 if (nh->nh_dev == NULL)
929 goto failure;
930 } else {
931 change_nexthops(fi) {
932 err = fib_check_nh(cfg, fi, nexthop_nh);
933 if (err != 0)
934 goto failure;
935 } endfor_nexthops(fi)
936 }
937
938 if (fi->fib_prefsrc) {
939 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
940 fi->fib_prefsrc != cfg->fc_dst)
941 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
942 goto err_inval;
943 }
944
945 change_nexthops(fi) {
946 fib_info_update_nh_saddr(net, nexthop_nh);
947 } endfor_nexthops(fi)
948
949 link_it:
950 ofi = fib_find_info(fi);
951 if (ofi) {
952 fi->fib_dead = 1;
953 free_fib_info(fi);
954 ofi->fib_treeref++;
955 return ofi;
956 }
957
958 fi->fib_treeref++;
959 atomic_inc(&fi->fib_clntref);
960 spin_lock_bh(&fib_info_lock);
961 hlist_add_head(&fi->fib_hash,
962 &fib_info_hash[fib_info_hashfn(fi)]);
963 if (fi->fib_prefsrc) {
964 struct hlist_head *head;
965
966 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
967 hlist_add_head(&fi->fib_lhash, head);
968 }
969 change_nexthops(fi) {
970 struct hlist_head *head;
971 unsigned int hash;
972
973 if (!nexthop_nh->nh_dev)
974 continue;
975 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
976 head = &fib_info_devhash[hash];
977 hlist_add_head(&nexthop_nh->nh_hash, head);
978 } endfor_nexthops(fi)
979 spin_unlock_bh(&fib_info_lock);
980 return fi;
981
982 err_inval:
983 err = -EINVAL;
984
985 failure:
986 if (fi) {
987 fi->fib_dead = 1;
988 free_fib_info(fi);
989 }
990
991 return ERR_PTR(err);
992 }
993
994 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
995 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
996 struct fib_info *fi, unsigned int flags)
997 {
998 struct nlmsghdr *nlh;
999 struct rtmsg *rtm;
1000
1001 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1002 if (nlh == NULL)
1003 return -EMSGSIZE;
1004
1005 rtm = nlmsg_data(nlh);
1006 rtm->rtm_family = AF_INET;
1007 rtm->rtm_dst_len = dst_len;
1008 rtm->rtm_src_len = 0;
1009 rtm->rtm_tos = tos;
1010 if (tb_id < 256)
1011 rtm->rtm_table = tb_id;
1012 else
1013 rtm->rtm_table = RT_TABLE_COMPAT;
1014 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1015 goto nla_put_failure;
1016 rtm->rtm_type = type;
1017 rtm->rtm_flags = fi->fib_flags;
1018 rtm->rtm_scope = fi->fib_scope;
1019 rtm->rtm_protocol = fi->fib_protocol;
1020
1021 if (rtm->rtm_dst_len &&
1022 nla_put_be32(skb, RTA_DST, dst))
1023 goto nla_put_failure;
1024 if (fi->fib_priority &&
1025 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1026 goto nla_put_failure;
1027 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1028 goto nla_put_failure;
1029
1030 if (fi->fib_prefsrc &&
1031 nla_put_be32(skb, RTA_PREFSRC, fi->fib_prefsrc))
1032 goto nla_put_failure;
1033 if (fi->fib_nhs == 1) {
1034 if (fi->fib_nh->nh_gw &&
1035 nla_put_be32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1036 goto nla_put_failure;
1037 if (fi->fib_nh->nh_oif &&
1038 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1039 goto nla_put_failure;
1040 #ifdef CONFIG_IP_ROUTE_CLASSID
1041 if (fi->fib_nh[0].nh_tclassid &&
1042 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1043 goto nla_put_failure;
1044 #endif
1045 }
1046 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1047 if (fi->fib_nhs > 1) {
1048 struct rtnexthop *rtnh;
1049 struct nlattr *mp;
1050
1051 mp = nla_nest_start(skb, RTA_MULTIPATH);
1052 if (mp == NULL)
1053 goto nla_put_failure;
1054
1055 for_nexthops(fi) {
1056 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1057 if (rtnh == NULL)
1058 goto nla_put_failure;
1059
1060 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1061 rtnh->rtnh_hops = nh->nh_weight - 1;
1062 rtnh->rtnh_ifindex = nh->nh_oif;
1063
1064 if (nh->nh_gw &&
1065 nla_put_be32(skb, RTA_GATEWAY, nh->nh_gw))
1066 goto nla_put_failure;
1067 #ifdef CONFIG_IP_ROUTE_CLASSID
1068 if (nh->nh_tclassid &&
1069 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1070 goto nla_put_failure;
1071 #endif
1072 /* length of rtnetlink header + attributes */
1073 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1074 } endfor_nexthops(fi);
1075
1076 nla_nest_end(skb, mp);
1077 }
1078 #endif
1079 return nlmsg_end(skb, nlh);
1080
1081 nla_put_failure:
1082 nlmsg_cancel(skb, nlh);
1083 return -EMSGSIZE;
1084 }
1085
1086 /*
1087 * Update FIB if:
1088 * - local address disappeared -> we must delete all the entries
1089 * referring to it.
1090 * - device went down -> we must shutdown all nexthops going via it.
1091 */
1092 int fib_sync_down_addr(struct net *net, __be32 local)
1093 {
1094 int ret = 0;
1095 unsigned int hash = fib_laddr_hashfn(local);
1096 struct hlist_head *head = &fib_info_laddrhash[hash];
1097 struct fib_info *fi;
1098
1099 if (fib_info_laddrhash == NULL || local == 0)
1100 return 0;
1101
1102 hlist_for_each_entry(fi, head, fib_lhash) {
1103 if (!net_eq(fi->fib_net, net))
1104 continue;
1105 if (fi->fib_prefsrc == local) {
1106 fi->fib_flags |= RTNH_F_DEAD;
1107 ret++;
1108 }
1109 }
1110 return ret;
1111 }
1112
1113 int fib_sync_down_dev(struct net_device *dev, int force)
1114 {
1115 int ret = 0;
1116 int scope = RT_SCOPE_NOWHERE;
1117 struct fib_info *prev_fi = NULL;
1118 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1119 struct hlist_head *head = &fib_info_devhash[hash];
1120 struct fib_nh *nh;
1121
1122 if (force)
1123 scope = -1;
1124
1125 hlist_for_each_entry(nh, head, nh_hash) {
1126 struct fib_info *fi = nh->nh_parent;
1127 int dead;
1128
1129 BUG_ON(!fi->fib_nhs);
1130 if (nh->nh_dev != dev || fi == prev_fi)
1131 continue;
1132 prev_fi = fi;
1133 dead = 0;
1134 change_nexthops(fi) {
1135 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1136 dead++;
1137 else if (nexthop_nh->nh_dev == dev &&
1138 nexthop_nh->nh_scope != scope) {
1139 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1140 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1141 spin_lock_bh(&fib_multipath_lock);
1142 fi->fib_power -= nexthop_nh->nh_power;
1143 nexthop_nh->nh_power = 0;
1144 spin_unlock_bh(&fib_multipath_lock);
1145 #endif
1146 dead++;
1147 }
1148 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1149 if (force > 1 && nexthop_nh->nh_dev == dev) {
1150 dead = fi->fib_nhs;
1151 break;
1152 }
1153 #endif
1154 } endfor_nexthops(fi)
1155 if (dead == fi->fib_nhs) {
1156 fi->fib_flags |= RTNH_F_DEAD;
1157 ret++;
1158 }
1159 }
1160
1161 return ret;
1162 }
1163
1164 /* Must be invoked inside of an RCU protected region. */
1165 void fib_select_default(struct fib_result *res)
1166 {
1167 struct fib_info *fi = NULL, *last_resort = NULL;
1168 struct list_head *fa_head = res->fa_head;
1169 struct fib_table *tb = res->table;
1170 int order = -1, last_idx = -1;
1171 struct fib_alias *fa;
1172
1173 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1174 struct fib_info *next_fi = fa->fa_info;
1175
1176 if (next_fi->fib_scope != res->scope ||
1177 fa->fa_type != RTN_UNICAST)
1178 continue;
1179
1180 if (next_fi->fib_priority > res->fi->fib_priority)
1181 break;
1182 if (!next_fi->fib_nh[0].nh_gw ||
1183 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1184 continue;
1185
1186 fib_alias_accessed(fa);
1187
1188 if (fi == NULL) {
1189 if (next_fi != res->fi)
1190 break;
1191 } else if (!fib_detect_death(fi, order, &last_resort,
1192 &last_idx, tb->tb_default)) {
1193 fib_result_assign(res, fi);
1194 tb->tb_default = order;
1195 goto out;
1196 }
1197 fi = next_fi;
1198 order++;
1199 }
1200
1201 if (order <= 0 || fi == NULL) {
1202 tb->tb_default = -1;
1203 goto out;
1204 }
1205
1206 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1207 tb->tb_default)) {
1208 fib_result_assign(res, fi);
1209 tb->tb_default = order;
1210 goto out;
1211 }
1212
1213 if (last_idx >= 0)
1214 fib_result_assign(res, last_resort);
1215 tb->tb_default = last_idx;
1216 out:
1217 return;
1218 }
1219
1220 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1221
1222 /*
1223 * Dead device goes up. We wake up dead nexthops.
1224 * It takes sense only on multipath routes.
1225 */
1226 int fib_sync_up(struct net_device *dev)
1227 {
1228 struct fib_info *prev_fi;
1229 unsigned int hash;
1230 struct hlist_head *head;
1231 struct fib_nh *nh;
1232 int ret;
1233
1234 if (!(dev->flags & IFF_UP))
1235 return 0;
1236
1237 prev_fi = NULL;
1238 hash = fib_devindex_hashfn(dev->ifindex);
1239 head = &fib_info_devhash[hash];
1240 ret = 0;
1241
1242 hlist_for_each_entry(nh, head, nh_hash) {
1243 struct fib_info *fi = nh->nh_parent;
1244 int alive;
1245
1246 BUG_ON(!fi->fib_nhs);
1247 if (nh->nh_dev != dev || fi == prev_fi)
1248 continue;
1249
1250 prev_fi = fi;
1251 alive = 0;
1252 change_nexthops(fi) {
1253 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1254 alive++;
1255 continue;
1256 }
1257 if (nexthop_nh->nh_dev == NULL ||
1258 !(nexthop_nh->nh_dev->flags & IFF_UP))
1259 continue;
1260 if (nexthop_nh->nh_dev != dev ||
1261 !__in_dev_get_rtnl(dev))
1262 continue;
1263 alive++;
1264 spin_lock_bh(&fib_multipath_lock);
1265 nexthop_nh->nh_power = 0;
1266 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1267 spin_unlock_bh(&fib_multipath_lock);
1268 } endfor_nexthops(fi)
1269
1270 if (alive > 0) {
1271 fi->fib_flags &= ~RTNH_F_DEAD;
1272 ret++;
1273 }
1274 }
1275
1276 return ret;
1277 }
1278
1279 /*
1280 * The algorithm is suboptimal, but it provides really
1281 * fair weighted route distribution.
1282 */
1283 void fib_select_multipath(struct fib_result *res)
1284 {
1285 struct fib_info *fi = res->fi;
1286 int w;
1287
1288 spin_lock_bh(&fib_multipath_lock);
1289 if (fi->fib_power <= 0) {
1290 int power = 0;
1291 change_nexthops(fi) {
1292 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1293 power += nexthop_nh->nh_weight;
1294 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1295 }
1296 } endfor_nexthops(fi);
1297 fi->fib_power = power;
1298 if (power <= 0) {
1299 spin_unlock_bh(&fib_multipath_lock);
1300 /* Race condition: route has just become dead. */
1301 res->nh_sel = 0;
1302 return;
1303 }
1304 }
1305
1306
1307 /* w should be random number [0..fi->fib_power-1],
1308 * it is pretty bad approximation.
1309 */
1310
1311 w = jiffies % fi->fib_power;
1312
1313 change_nexthops(fi) {
1314 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1315 nexthop_nh->nh_power) {
1316 w -= nexthop_nh->nh_power;
1317 if (w <= 0) {
1318 nexthop_nh->nh_power--;
1319 fi->fib_power--;
1320 res->nh_sel = nhsel;
1321 spin_unlock_bh(&fib_multipath_lock);
1322 return;
1323 }
1324 }
1325 } endfor_nexthops(fi);
1326
1327 /* Race condition: route has just become dead. */
1328 res->nh_sel = 0;
1329 spin_unlock_bh(&fib_multipath_lock);
1330 }
1331 #endif
kernel source for telekom puls (alcatel/mediatek)