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