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[mirror_ubuntu-bionic-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 <asm/system.h>
18 #include <linux/bitops.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/jiffies.h>
22 #include <linux/mm.h>
23 #include <linux/string.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/errno.h>
27 #include <linux/in.h>
28 #include <linux/inet.h>
29 #include <linux/inetdevice.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/proc_fs.h>
33 #include <linux/skbuff.h>
34 #include <linux/init.h>
35 #include <linux/slab.h>
36
37 #include <net/arp.h>
38 #include <net/ip.h>
39 #include <net/protocol.h>
40 #include <net/route.h>
41 #include <net/tcp.h>
42 #include <net/sock.h>
43 #include <net/ip_fib.h>
44 #include <net/netlink.h>
45 #include <net/nexthop.h>
46
47 #include "fib_lookup.h"
48
49 static DEFINE_SPINLOCK(fib_info_lock);
50 static struct hlist_head *fib_info_hash;
51 static struct hlist_head *fib_info_laddrhash;
52 static unsigned int fib_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61 static DEFINE_SPINLOCK(fib_multipath_lock);
62
63 #define for_nexthops(fi) { int nhsel; const struct fib_nh * nh; \
64 for (nhsel=0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
65
66 #define change_nexthops(fi) { int nhsel; struct fib_nh *nexthop_nh; \
67 for (nhsel=0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nexthop_nh++, nhsel++)
68
69 #else /* CONFIG_IP_ROUTE_MULTIPATH */
70
71 /* Hope, that gcc will optimize it to get rid of dummy loop */
72
73 #define for_nexthops(fi) { int nhsel = 0; const struct fib_nh * nh = (fi)->fib_nh; \
74 for (nhsel=0; nhsel < 1; nhsel++)
75
76 #define change_nexthops(fi) { int nhsel = 0; struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
77 for (nhsel=0; nhsel < 1; nhsel++)
78
79 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
80
81 #define endfor_nexthops(fi) }
82
83
84 static const struct
85 {
86 int error;
87 u8 scope;
88 } fib_props[RTN_MAX + 1] = {
89 {
90 .error = 0,
91 .scope = RT_SCOPE_NOWHERE,
92 }, /* RTN_UNSPEC */
93 {
94 .error = 0,
95 .scope = RT_SCOPE_UNIVERSE,
96 }, /* RTN_UNICAST */
97 {
98 .error = 0,
99 .scope = RT_SCOPE_HOST,
100 }, /* RTN_LOCAL */
101 {
102 .error = 0,
103 .scope = RT_SCOPE_LINK,
104 }, /* RTN_BROADCAST */
105 {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 }, /* RTN_ANYCAST */
109 {
110 .error = 0,
111 .scope = RT_SCOPE_UNIVERSE,
112 }, /* RTN_MULTICAST */
113 {
114 .error = -EINVAL,
115 .scope = RT_SCOPE_UNIVERSE,
116 }, /* RTN_BLACKHOLE */
117 {
118 .error = -EHOSTUNREACH,
119 .scope = RT_SCOPE_UNIVERSE,
120 }, /* RTN_UNREACHABLE */
121 {
122 .error = -EACCES,
123 .scope = RT_SCOPE_UNIVERSE,
124 }, /* RTN_PROHIBIT */
125 {
126 .error = -EAGAIN,
127 .scope = RT_SCOPE_UNIVERSE,
128 }, /* RTN_THROW */
129 {
130 .error = -EINVAL,
131 .scope = RT_SCOPE_NOWHERE,
132 }, /* RTN_NAT */
133 {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 }, /* RTN_XRESOLVE */
137 };
138
139
140 /* Release a nexthop info record */
141
142 void free_fib_info(struct fib_info *fi)
143 {
144 if (fi->fib_dead == 0) {
145 printk(KERN_WARNING "Freeing alive fib_info %p\n", fi);
146 return;
147 }
148 change_nexthops(fi) {
149 if (nexthop_nh->nh_dev)
150 dev_put(nexthop_nh->nh_dev);
151 nexthop_nh->nh_dev = NULL;
152 } endfor_nexthops(fi);
153 fib_info_cnt--;
154 release_net(fi->fib_net);
155 kfree(fi);
156 }
157
158 void fib_release_info(struct fib_info *fi)
159 {
160 spin_lock_bh(&fib_info_lock);
161 if (fi && --fi->fib_treeref == 0) {
162 hlist_del(&fi->fib_hash);
163 if (fi->fib_prefsrc)
164 hlist_del(&fi->fib_lhash);
165 change_nexthops(fi) {
166 if (!nexthop_nh->nh_dev)
167 continue;
168 hlist_del(&nexthop_nh->nh_hash);
169 } endfor_nexthops(fi)
170 fi->fib_dead = 1;
171 fib_info_put(fi);
172 }
173 spin_unlock_bh(&fib_info_lock);
174 }
175
176 static __inline__ int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
177 {
178 const struct fib_nh *onh = ofi->fib_nh;
179
180 for_nexthops(fi) {
181 if (nh->nh_oif != onh->nh_oif ||
182 nh->nh_gw != onh->nh_gw ||
183 nh->nh_scope != onh->nh_scope ||
184 #ifdef CONFIG_IP_ROUTE_MULTIPATH
185 nh->nh_weight != onh->nh_weight ||
186 #endif
187 #ifdef CONFIG_NET_CLS_ROUTE
188 nh->nh_tclassid != onh->nh_tclassid ||
189 #endif
190 ((nh->nh_flags^onh->nh_flags)&~RTNH_F_DEAD))
191 return -1;
192 onh++;
193 } endfor_nexthops(fi);
194 return 0;
195 }
196
197 static inline unsigned int fib_devindex_hashfn(unsigned int val)
198 {
199 unsigned int mask = DEVINDEX_HASHSIZE - 1;
200
201 return (val ^
202 (val >> DEVINDEX_HASHBITS) ^
203 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
204 }
205
206 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
207 {
208 unsigned int mask = (fib_hash_size - 1);
209 unsigned int val = fi->fib_nhs;
210
211 val ^= fi->fib_protocol;
212 val ^= (__force u32)fi->fib_prefsrc;
213 val ^= fi->fib_priority;
214 for_nexthops(fi) {
215 val ^= fib_devindex_hashfn(nh->nh_oif);
216 } endfor_nexthops(fi)
217
218 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
219 }
220
221 static struct fib_info *fib_find_info(const struct fib_info *nfi)
222 {
223 struct hlist_head *head;
224 struct hlist_node *node;
225 struct fib_info *fi;
226 unsigned int hash;
227
228 hash = fib_info_hashfn(nfi);
229 head = &fib_info_hash[hash];
230
231 hlist_for_each_entry(fi, node, head, fib_hash) {
232 if (!net_eq(fi->fib_net, nfi->fib_net))
233 continue;
234 if (fi->fib_nhs != nfi->fib_nhs)
235 continue;
236 if (nfi->fib_protocol == fi->fib_protocol &&
237 nfi->fib_prefsrc == fi->fib_prefsrc &&
238 nfi->fib_priority == fi->fib_priority &&
239 memcmp(nfi->fib_metrics, fi->fib_metrics,
240 sizeof(fi->fib_metrics)) == 0 &&
241 ((nfi->fib_flags^fi->fib_flags)&~RTNH_F_DEAD) == 0 &&
242 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
243 return fi;
244 }
245
246 return NULL;
247 }
248
249 /* Check, that the gateway is already configured.
250 Used only by redirect accept routine.
251 */
252
253 int ip_fib_check_default(__be32 gw, struct net_device *dev)
254 {
255 struct hlist_head *head;
256 struct hlist_node *node;
257 struct fib_nh *nh;
258 unsigned int hash;
259
260 spin_lock(&fib_info_lock);
261
262 hash = fib_devindex_hashfn(dev->ifindex);
263 head = &fib_info_devhash[hash];
264 hlist_for_each_entry(nh, node, head, nh_hash) {
265 if (nh->nh_dev == dev &&
266 nh->nh_gw == gw &&
267 !(nh->nh_flags&RTNH_F_DEAD)) {
268 spin_unlock(&fib_info_lock);
269 return 0;
270 }
271 }
272
273 spin_unlock(&fib_info_lock);
274
275 return -1;
276 }
277
278 static inline size_t fib_nlmsg_size(struct fib_info *fi)
279 {
280 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
281 + nla_total_size(4) /* RTA_TABLE */
282 + nla_total_size(4) /* RTA_DST */
283 + nla_total_size(4) /* RTA_PRIORITY */
284 + nla_total_size(4); /* RTA_PREFSRC */
285
286 /* space for nested metrics */
287 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
288
289 if (fi->fib_nhs) {
290 /* Also handles the special case fib_nhs == 1 */
291
292 /* each nexthop is packed in an attribute */
293 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
294
295 /* may contain flow and gateway attribute */
296 nhsize += 2 * nla_total_size(4);
297
298 /* all nexthops are packed in a nested attribute */
299 payload += nla_total_size(fi->fib_nhs * nhsize);
300 }
301
302 return payload;
303 }
304
305 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
306 int dst_len, u32 tb_id, struct nl_info *info,
307 unsigned int nlm_flags)
308 {
309 struct sk_buff *skb;
310 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
311 int err = -ENOBUFS;
312
313 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
314 if (skb == NULL)
315 goto errout;
316
317 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
318 fa->fa_type, fa->fa_scope, key, dst_len,
319 fa->fa_tos, fa->fa_info, nlm_flags);
320 if (err < 0) {
321 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
322 WARN_ON(err == -EMSGSIZE);
323 kfree_skb(skb);
324 goto errout;
325 }
326 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
327 info->nlh, GFP_KERNEL);
328 return;
329 errout:
330 if (err < 0)
331 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
332 }
333
334 /* Return the first fib alias matching TOS with
335 * priority less than or equal to PRIO.
336 */
337 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
338 {
339 if (fah) {
340 struct fib_alias *fa;
341 list_for_each_entry(fa, fah, fa_list) {
342 if (fa->fa_tos > tos)
343 continue;
344 if (fa->fa_info->fib_priority >= prio ||
345 fa->fa_tos < tos)
346 return fa;
347 }
348 }
349 return NULL;
350 }
351
352 int fib_detect_death(struct fib_info *fi, int order,
353 struct fib_info **last_resort, int *last_idx, int dflt)
354 {
355 struct neighbour *n;
356 int state = NUD_NONE;
357
358 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
359 if (n) {
360 state = n->nud_state;
361 neigh_release(n);
362 }
363 if (state == NUD_REACHABLE)
364 return 0;
365 if ((state&NUD_VALID) && order != dflt)
366 return 0;
367 if ((state&NUD_VALID) ||
368 (*last_idx<0 && order > dflt)) {
369 *last_resort = fi;
370 *last_idx = order;
371 }
372 return 1;
373 }
374
375 #ifdef CONFIG_IP_ROUTE_MULTIPATH
376
377 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
378 {
379 int nhs = 0;
380
381 while (rtnh_ok(rtnh, remaining)) {
382 nhs++;
383 rtnh = rtnh_next(rtnh, &remaining);
384 }
385
386 /* leftover implies invalid nexthop configuration, discard it */
387 return remaining > 0 ? 0 : nhs;
388 }
389
390 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
391 int remaining, struct fib_config *cfg)
392 {
393 change_nexthops(fi) {
394 int attrlen;
395
396 if (!rtnh_ok(rtnh, remaining))
397 return -EINVAL;
398
399 nexthop_nh->nh_flags =
400 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
401 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
402 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
403
404 attrlen = rtnh_attrlen(rtnh);
405 if (attrlen > 0) {
406 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
407
408 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
409 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
410 #ifdef CONFIG_NET_CLS_ROUTE
411 nla = nla_find(attrs, attrlen, RTA_FLOW);
412 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
413 #endif
414 }
415
416 rtnh = rtnh_next(rtnh, &remaining);
417 } endfor_nexthops(fi);
418
419 return 0;
420 }
421
422 #endif
423
424 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
425 {
426 #ifdef CONFIG_IP_ROUTE_MULTIPATH
427 struct rtnexthop *rtnh;
428 int remaining;
429 #endif
430
431 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
432 return 1;
433
434 if (cfg->fc_oif || cfg->fc_gw) {
435 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
436 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
437 return 0;
438 return 1;
439 }
440
441 #ifdef CONFIG_IP_ROUTE_MULTIPATH
442 if (cfg->fc_mp == NULL)
443 return 0;
444
445 rtnh = cfg->fc_mp;
446 remaining = cfg->fc_mp_len;
447
448 for_nexthops(fi) {
449 int attrlen;
450
451 if (!rtnh_ok(rtnh, remaining))
452 return -EINVAL;
453
454 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
455 return 1;
456
457 attrlen = rtnh_attrlen(rtnh);
458 if (attrlen < 0) {
459 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
460
461 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
462 if (nla && nla_get_be32(nla) != nh->nh_gw)
463 return 1;
464 #ifdef CONFIG_NET_CLS_ROUTE
465 nla = nla_find(attrs, attrlen, RTA_FLOW);
466 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
467 return 1;
468 #endif
469 }
470
471 rtnh = rtnh_next(rtnh, &remaining);
472 } endfor_nexthops(fi);
473 #endif
474 return 0;
475 }
476
477
478 /*
479 Picture
480 -------
481
482 Semantics of nexthop is very messy by historical reasons.
483 We have to take into account, that:
484 a) gateway can be actually local interface address,
485 so that gatewayed route is direct.
486 b) gateway must be on-link address, possibly
487 described not by an ifaddr, but also by a direct route.
488 c) If both gateway and interface are specified, they should not
489 contradict.
490 d) If we use tunnel routes, gateway could be not on-link.
491
492 Attempt to reconcile all of these (alas, self-contradictory) conditions
493 results in pretty ugly and hairy code with obscure logic.
494
495 I chose to generalized it instead, so that the size
496 of code does not increase practically, but it becomes
497 much more general.
498 Every prefix is assigned a "scope" value: "host" is local address,
499 "link" is direct route,
500 [ ... "site" ... "interior" ... ]
501 and "universe" is true gateway route with global meaning.
502
503 Every prefix refers to a set of "nexthop"s (gw, oif),
504 where gw must have narrower scope. This recursion stops
505 when gw has LOCAL scope or if "nexthop" is declared ONLINK,
506 which means that gw is forced to be on link.
507
508 Code is still hairy, but now it is apparently logically
509 consistent and very flexible. F.e. as by-product it allows
510 to co-exists in peace independent exterior and interior
511 routing processes.
512
513 Normally it looks as following.
514
515 {universe prefix} -> (gw, oif) [scope link]
516 |
517 |-> {link prefix} -> (gw, oif) [scope local]
518 |
519 |-> {local prefix} (terminal node)
520 */
521
522 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
523 struct fib_nh *nh)
524 {
525 int err;
526 struct net *net;
527
528 net = cfg->fc_nlinfo.nl_net;
529 if (nh->nh_gw) {
530 struct fib_result res;
531
532 if (nh->nh_flags&RTNH_F_ONLINK) {
533 struct net_device *dev;
534
535 if (cfg->fc_scope >= RT_SCOPE_LINK)
536 return -EINVAL;
537 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
538 return -EINVAL;
539 if ((dev = __dev_get_by_index(net, nh->nh_oif)) == NULL)
540 return -ENODEV;
541 if (!(dev->flags&IFF_UP))
542 return -ENETDOWN;
543 nh->nh_dev = dev;
544 dev_hold(dev);
545 nh->nh_scope = RT_SCOPE_LINK;
546 return 0;
547 }
548 {
549 struct flowi fl = {
550 .nl_u = {
551 .ip4_u = {
552 .daddr = nh->nh_gw,
553 .scope = cfg->fc_scope + 1,
554 },
555 },
556 .oif = nh->nh_oif,
557 };
558
559 /* It is not necessary, but requires a bit of thinking */
560 if (fl.fl4_scope < RT_SCOPE_LINK)
561 fl.fl4_scope = RT_SCOPE_LINK;
562 if ((err = fib_lookup(net, &fl, &res)) != 0)
563 return err;
564 }
565 err = -EINVAL;
566 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
567 goto out;
568 nh->nh_scope = res.scope;
569 nh->nh_oif = FIB_RES_OIF(res);
570 if ((nh->nh_dev = FIB_RES_DEV(res)) == NULL)
571 goto out;
572 dev_hold(nh->nh_dev);
573 err = -ENETDOWN;
574 if (!(nh->nh_dev->flags & IFF_UP))
575 goto out;
576 err = 0;
577 out:
578 fib_res_put(&res);
579 return err;
580 } else {
581 struct in_device *in_dev;
582
583 if (nh->nh_flags&(RTNH_F_PERVASIVE|RTNH_F_ONLINK))
584 return -EINVAL;
585
586 in_dev = inetdev_by_index(net, nh->nh_oif);
587 if (in_dev == NULL)
588 return -ENODEV;
589 if (!(in_dev->dev->flags&IFF_UP)) {
590 in_dev_put(in_dev);
591 return -ENETDOWN;
592 }
593 nh->nh_dev = in_dev->dev;
594 dev_hold(nh->nh_dev);
595 nh->nh_scope = RT_SCOPE_HOST;
596 in_dev_put(in_dev);
597 }
598 return 0;
599 }
600
601 static inline unsigned int fib_laddr_hashfn(__be32 val)
602 {
603 unsigned int mask = (fib_hash_size - 1);
604
605 return ((__force u32)val ^ ((__force u32)val >> 7) ^ ((__force u32)val >> 14)) & mask;
606 }
607
608 static struct hlist_head *fib_hash_alloc(int bytes)
609 {
610 if (bytes <= PAGE_SIZE)
611 return kzalloc(bytes, GFP_KERNEL);
612 else
613 return (struct hlist_head *)
614 __get_free_pages(GFP_KERNEL | __GFP_ZERO, get_order(bytes));
615 }
616
617 static void fib_hash_free(struct hlist_head *hash, int bytes)
618 {
619 if (!hash)
620 return;
621
622 if (bytes <= PAGE_SIZE)
623 kfree(hash);
624 else
625 free_pages((unsigned long) hash, get_order(bytes));
626 }
627
628 static void fib_hash_move(struct hlist_head *new_info_hash,
629 struct hlist_head *new_laddrhash,
630 unsigned int new_size)
631 {
632 struct hlist_head *old_info_hash, *old_laddrhash;
633 unsigned int old_size = fib_hash_size;
634 unsigned int i, bytes;
635
636 spin_lock_bh(&fib_info_lock);
637 old_info_hash = fib_info_hash;
638 old_laddrhash = fib_info_laddrhash;
639 fib_hash_size = new_size;
640
641 for (i = 0; i < old_size; i++) {
642 struct hlist_head *head = &fib_info_hash[i];
643 struct hlist_node *node, *n;
644 struct fib_info *fi;
645
646 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
647 struct hlist_head *dest;
648 unsigned int new_hash;
649
650 hlist_del(&fi->fib_hash);
651
652 new_hash = fib_info_hashfn(fi);
653 dest = &new_info_hash[new_hash];
654 hlist_add_head(&fi->fib_hash, dest);
655 }
656 }
657 fib_info_hash = new_info_hash;
658
659 for (i = 0; i < old_size; i++) {
660 struct hlist_head *lhead = &fib_info_laddrhash[i];
661 struct hlist_node *node, *n;
662 struct fib_info *fi;
663
664 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
665 struct hlist_head *ldest;
666 unsigned int new_hash;
667
668 hlist_del(&fi->fib_lhash);
669
670 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
671 ldest = &new_laddrhash[new_hash];
672 hlist_add_head(&fi->fib_lhash, ldest);
673 }
674 }
675 fib_info_laddrhash = new_laddrhash;
676
677 spin_unlock_bh(&fib_info_lock);
678
679 bytes = old_size * sizeof(struct hlist_head *);
680 fib_hash_free(old_info_hash, bytes);
681 fib_hash_free(old_laddrhash, bytes);
682 }
683
684 struct fib_info *fib_create_info(struct fib_config *cfg)
685 {
686 int err;
687 struct fib_info *fi = NULL;
688 struct fib_info *ofi;
689 int nhs = 1;
690 struct net *net = cfg->fc_nlinfo.nl_net;
691
692 /* Fast check to catch the most weird cases */
693 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
694 goto err_inval;
695
696 #ifdef CONFIG_IP_ROUTE_MULTIPATH
697 if (cfg->fc_mp) {
698 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
699 if (nhs == 0)
700 goto err_inval;
701 }
702 #endif
703
704 err = -ENOBUFS;
705 if (fib_info_cnt >= fib_hash_size) {
706 unsigned int new_size = fib_hash_size << 1;
707 struct hlist_head *new_info_hash;
708 struct hlist_head *new_laddrhash;
709 unsigned int bytes;
710
711 if (!new_size)
712 new_size = 1;
713 bytes = new_size * sizeof(struct hlist_head *);
714 new_info_hash = fib_hash_alloc(bytes);
715 new_laddrhash = fib_hash_alloc(bytes);
716 if (!new_info_hash || !new_laddrhash) {
717 fib_hash_free(new_info_hash, bytes);
718 fib_hash_free(new_laddrhash, bytes);
719 } else
720 fib_hash_move(new_info_hash, new_laddrhash, new_size);
721
722 if (!fib_hash_size)
723 goto failure;
724 }
725
726 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
727 if (fi == NULL)
728 goto failure;
729 fib_info_cnt++;
730
731 fi->fib_net = hold_net(net);
732 fi->fib_protocol = cfg->fc_protocol;
733 fi->fib_flags = cfg->fc_flags;
734 fi->fib_priority = cfg->fc_priority;
735 fi->fib_prefsrc = cfg->fc_prefsrc;
736
737 fi->fib_nhs = nhs;
738 change_nexthops(fi) {
739 nexthop_nh->nh_parent = fi;
740 } endfor_nexthops(fi)
741
742 if (cfg->fc_mx) {
743 struct nlattr *nla;
744 int remaining;
745
746 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
747 int type = nla_type(nla);
748
749 if (type) {
750 if (type > RTAX_MAX)
751 goto err_inval;
752 fi->fib_metrics[type - 1] = nla_get_u32(nla);
753 }
754 }
755 }
756
757 if (cfg->fc_mp) {
758 #ifdef CONFIG_IP_ROUTE_MULTIPATH
759 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
760 if (err != 0)
761 goto failure;
762 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
763 goto err_inval;
764 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
765 goto err_inval;
766 #ifdef CONFIG_NET_CLS_ROUTE
767 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
768 goto err_inval;
769 #endif
770 #else
771 goto err_inval;
772 #endif
773 } else {
774 struct fib_nh *nh = fi->fib_nh;
775
776 nh->nh_oif = cfg->fc_oif;
777 nh->nh_gw = cfg->fc_gw;
778 nh->nh_flags = cfg->fc_flags;
779 #ifdef CONFIG_NET_CLS_ROUTE
780 nh->nh_tclassid = cfg->fc_flow;
781 #endif
782 #ifdef CONFIG_IP_ROUTE_MULTIPATH
783 nh->nh_weight = 1;
784 #endif
785 }
786
787 if (fib_props[cfg->fc_type].error) {
788 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
789 goto err_inval;
790 goto link_it;
791 }
792
793 if (cfg->fc_scope > RT_SCOPE_HOST)
794 goto err_inval;
795
796 if (cfg->fc_scope == RT_SCOPE_HOST) {
797 struct fib_nh *nh = fi->fib_nh;
798
799 /* Local address is added. */
800 if (nhs != 1 || nh->nh_gw)
801 goto err_inval;
802 nh->nh_scope = RT_SCOPE_NOWHERE;
803 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
804 err = -ENODEV;
805 if (nh->nh_dev == NULL)
806 goto failure;
807 } else {
808 change_nexthops(fi) {
809 if ((err = fib_check_nh(cfg, fi, nexthop_nh)) != 0)
810 goto failure;
811 } endfor_nexthops(fi)
812 }
813
814 if (fi->fib_prefsrc) {
815 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
816 fi->fib_prefsrc != cfg->fc_dst)
817 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
818 goto err_inval;
819 }
820
821 link_it:
822 if ((ofi = fib_find_info(fi)) != NULL) {
823 fi->fib_dead = 1;
824 free_fib_info(fi);
825 ofi->fib_treeref++;
826 return ofi;
827 }
828
829 fi->fib_treeref++;
830 atomic_inc(&fi->fib_clntref);
831 spin_lock_bh(&fib_info_lock);
832 hlist_add_head(&fi->fib_hash,
833 &fib_info_hash[fib_info_hashfn(fi)]);
834 if (fi->fib_prefsrc) {
835 struct hlist_head *head;
836
837 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
838 hlist_add_head(&fi->fib_lhash, head);
839 }
840 change_nexthops(fi) {
841 struct hlist_head *head;
842 unsigned int hash;
843
844 if (!nexthop_nh->nh_dev)
845 continue;
846 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
847 head = &fib_info_devhash[hash];
848 hlist_add_head(&nexthop_nh->nh_hash, head);
849 } endfor_nexthops(fi)
850 spin_unlock_bh(&fib_info_lock);
851 return fi;
852
853 err_inval:
854 err = -EINVAL;
855
856 failure:
857 if (fi) {
858 fi->fib_dead = 1;
859 free_fib_info(fi);
860 }
861
862 return ERR_PTR(err);
863 }
864
865 /* Note! fib_semantic_match intentionally uses RCU list functions. */
866 int fib_semantic_match(struct list_head *head, const struct flowi *flp,
867 struct fib_result *res, int prefixlen)
868 {
869 struct fib_alias *fa;
870 int nh_sel = 0;
871
872 list_for_each_entry_rcu(fa, head, fa_list) {
873 int err;
874
875 if (fa->fa_tos &&
876 fa->fa_tos != flp->fl4_tos)
877 continue;
878
879 if (fa->fa_scope < flp->fl4_scope)
880 continue;
881
882 fa->fa_state |= FA_S_ACCESSED;
883
884 err = fib_props[fa->fa_type].error;
885 if (err == 0) {
886 struct fib_info *fi = fa->fa_info;
887
888 if (fi->fib_flags & RTNH_F_DEAD)
889 continue;
890
891 switch (fa->fa_type) {
892 case RTN_UNICAST:
893 case RTN_LOCAL:
894 case RTN_BROADCAST:
895 case RTN_ANYCAST:
896 case RTN_MULTICAST:
897 for_nexthops(fi) {
898 if (nh->nh_flags&RTNH_F_DEAD)
899 continue;
900 if (!flp->oif || flp->oif == nh->nh_oif)
901 break;
902 }
903 #ifdef CONFIG_IP_ROUTE_MULTIPATH
904 if (nhsel < fi->fib_nhs) {
905 nh_sel = nhsel;
906 goto out_fill_res;
907 }
908 #else
909 if (nhsel < 1) {
910 goto out_fill_res;
911 }
912 #endif
913 endfor_nexthops(fi);
914 continue;
915
916 default:
917 printk(KERN_WARNING "fib_semantic_match bad type %#x\n",
918 fa->fa_type);
919 return -EINVAL;
920 }
921 }
922 return err;
923 }
924 return 1;
925
926 out_fill_res:
927 res->prefixlen = prefixlen;
928 res->nh_sel = nh_sel;
929 res->type = fa->fa_type;
930 res->scope = fa->fa_scope;
931 res->fi = fa->fa_info;
932 atomic_inc(&res->fi->fib_clntref);
933 return 0;
934 }
935
936 /* Find appropriate source address to this destination */
937
938 __be32 __fib_res_prefsrc(struct fib_result *res)
939 {
940 return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
941 }
942
943 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
944 u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8 tos,
945 struct fib_info *fi, unsigned int flags)
946 {
947 struct nlmsghdr *nlh;
948 struct rtmsg *rtm;
949
950 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
951 if (nlh == NULL)
952 return -EMSGSIZE;
953
954 rtm = nlmsg_data(nlh);
955 rtm->rtm_family = AF_INET;
956 rtm->rtm_dst_len = dst_len;
957 rtm->rtm_src_len = 0;
958 rtm->rtm_tos = tos;
959 if (tb_id < 256)
960 rtm->rtm_table = tb_id;
961 else
962 rtm->rtm_table = RT_TABLE_COMPAT;
963 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
964 rtm->rtm_type = type;
965 rtm->rtm_flags = fi->fib_flags;
966 rtm->rtm_scope = scope;
967 rtm->rtm_protocol = fi->fib_protocol;
968
969 if (rtm->rtm_dst_len)
970 NLA_PUT_BE32(skb, RTA_DST, dst);
971
972 if (fi->fib_priority)
973 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
974
975 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
976 goto nla_put_failure;
977
978 if (fi->fib_prefsrc)
979 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
980
981 if (fi->fib_nhs == 1) {
982 if (fi->fib_nh->nh_gw)
983 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
984
985 if (fi->fib_nh->nh_oif)
986 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
987 #ifdef CONFIG_NET_CLS_ROUTE
988 if (fi->fib_nh[0].nh_tclassid)
989 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
990 #endif
991 }
992 #ifdef CONFIG_IP_ROUTE_MULTIPATH
993 if (fi->fib_nhs > 1) {
994 struct rtnexthop *rtnh;
995 struct nlattr *mp;
996
997 mp = nla_nest_start(skb, RTA_MULTIPATH);
998 if (mp == NULL)
999 goto nla_put_failure;
1000
1001 for_nexthops(fi) {
1002 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1003 if (rtnh == NULL)
1004 goto nla_put_failure;
1005
1006 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1007 rtnh->rtnh_hops = nh->nh_weight - 1;
1008 rtnh->rtnh_ifindex = nh->nh_oif;
1009
1010 if (nh->nh_gw)
1011 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
1012 #ifdef CONFIG_NET_CLS_ROUTE
1013 if (nh->nh_tclassid)
1014 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
1015 #endif
1016 /* length of rtnetlink header + attributes */
1017 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1018 } endfor_nexthops(fi);
1019
1020 nla_nest_end(skb, mp);
1021 }
1022 #endif
1023 return nlmsg_end(skb, nlh);
1024
1025 nla_put_failure:
1026 nlmsg_cancel(skb, nlh);
1027 return -EMSGSIZE;
1028 }
1029
1030 /*
1031 Update FIB if:
1032 - local address disappeared -> we must delete all the entries
1033 referring to it.
1034 - device went down -> we must shutdown all nexthops going via it.
1035 */
1036 int fib_sync_down_addr(struct net *net, __be32 local)
1037 {
1038 int ret = 0;
1039 unsigned int hash = fib_laddr_hashfn(local);
1040 struct hlist_head *head = &fib_info_laddrhash[hash];
1041 struct hlist_node *node;
1042 struct fib_info *fi;
1043
1044 if (fib_info_laddrhash == NULL || local == 0)
1045 return 0;
1046
1047 hlist_for_each_entry(fi, node, head, fib_lhash) {
1048 if (!net_eq(fi->fib_net, net))
1049 continue;
1050 if (fi->fib_prefsrc == local) {
1051 fi->fib_flags |= RTNH_F_DEAD;
1052 ret++;
1053 }
1054 }
1055 return ret;
1056 }
1057
1058 int fib_sync_down_dev(struct net_device *dev, int force)
1059 {
1060 int ret = 0;
1061 int scope = RT_SCOPE_NOWHERE;
1062 struct fib_info *prev_fi = NULL;
1063 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1064 struct hlist_head *head = &fib_info_devhash[hash];
1065 struct hlist_node *node;
1066 struct fib_nh *nh;
1067
1068 if (force)
1069 scope = -1;
1070
1071 hlist_for_each_entry(nh, node, head, nh_hash) {
1072 struct fib_info *fi = nh->nh_parent;
1073 int dead;
1074
1075 BUG_ON(!fi->fib_nhs);
1076 if (nh->nh_dev != dev || fi == prev_fi)
1077 continue;
1078 prev_fi = fi;
1079 dead = 0;
1080 change_nexthops(fi) {
1081 if (nexthop_nh->nh_flags&RTNH_F_DEAD)
1082 dead++;
1083 else if (nexthop_nh->nh_dev == dev &&
1084 nexthop_nh->nh_scope != scope) {
1085 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1086 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1087 spin_lock_bh(&fib_multipath_lock);
1088 fi->fib_power -= nexthop_nh->nh_power;
1089 nexthop_nh->nh_power = 0;
1090 spin_unlock_bh(&fib_multipath_lock);
1091 #endif
1092 dead++;
1093 }
1094 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1095 if (force > 1 && nexthop_nh->nh_dev == dev) {
1096 dead = fi->fib_nhs;
1097 break;
1098 }
1099 #endif
1100 } endfor_nexthops(fi)
1101 if (dead == fi->fib_nhs) {
1102 fi->fib_flags |= RTNH_F_DEAD;
1103 ret++;
1104 }
1105 }
1106
1107 return ret;
1108 }
1109
1110 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1111
1112 /*
1113 Dead device goes up. We wake up dead nexthops.
1114 It takes sense only on multipath routes.
1115 */
1116
1117 int fib_sync_up(struct net_device *dev)
1118 {
1119 struct fib_info *prev_fi;
1120 unsigned int hash;
1121 struct hlist_head *head;
1122 struct hlist_node *node;
1123 struct fib_nh *nh;
1124 int ret;
1125
1126 if (!(dev->flags&IFF_UP))
1127 return 0;
1128
1129 prev_fi = NULL;
1130 hash = fib_devindex_hashfn(dev->ifindex);
1131 head = &fib_info_devhash[hash];
1132 ret = 0;
1133
1134 hlist_for_each_entry(nh, node, head, nh_hash) {
1135 struct fib_info *fi = nh->nh_parent;
1136 int alive;
1137
1138 BUG_ON(!fi->fib_nhs);
1139 if (nh->nh_dev != dev || fi == prev_fi)
1140 continue;
1141
1142 prev_fi = fi;
1143 alive = 0;
1144 change_nexthops(fi) {
1145 if (!(nexthop_nh->nh_flags&RTNH_F_DEAD)) {
1146 alive++;
1147 continue;
1148 }
1149 if (nexthop_nh->nh_dev == NULL ||
1150 !(nexthop_nh->nh_dev->flags&IFF_UP))
1151 continue;
1152 if (nexthop_nh->nh_dev != dev ||
1153 !__in_dev_get_rtnl(dev))
1154 continue;
1155 alive++;
1156 spin_lock_bh(&fib_multipath_lock);
1157 nexthop_nh->nh_power = 0;
1158 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1159 spin_unlock_bh(&fib_multipath_lock);
1160 } endfor_nexthops(fi)
1161
1162 if (alive > 0) {
1163 fi->fib_flags &= ~RTNH_F_DEAD;
1164 ret++;
1165 }
1166 }
1167
1168 return ret;
1169 }
1170
1171 /*
1172 The algorithm is suboptimal, but it provides really
1173 fair weighted route distribution.
1174 */
1175
1176 void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
1177 {
1178 struct fib_info *fi = res->fi;
1179 int w;
1180
1181 spin_lock_bh(&fib_multipath_lock);
1182 if (fi->fib_power <= 0) {
1183 int power = 0;
1184 change_nexthops(fi) {
1185 if (!(nexthop_nh->nh_flags&RTNH_F_DEAD)) {
1186 power += nexthop_nh->nh_weight;
1187 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1188 }
1189 } endfor_nexthops(fi);
1190 fi->fib_power = power;
1191 if (power <= 0) {
1192 spin_unlock_bh(&fib_multipath_lock);
1193 /* Race condition: route has just become dead. */
1194 res->nh_sel = 0;
1195 return;
1196 }
1197 }
1198
1199
1200 /* w should be random number [0..fi->fib_power-1],
1201 it is pretty bad approximation.
1202 */
1203
1204 w = jiffies % fi->fib_power;
1205
1206 change_nexthops(fi) {
1207 if (!(nexthop_nh->nh_flags&RTNH_F_DEAD) &&
1208 nexthop_nh->nh_power) {
1209 if ((w -= nexthop_nh->nh_power) <= 0) {
1210 nexthop_nh->nh_power--;
1211 fi->fib_power--;
1212 res->nh_sel = nhsel;
1213 spin_unlock_bh(&fib_multipath_lock);
1214 return;
1215 }
1216 }
1217 } endfor_nexthops(fi);
1218
1219 /* Race condition: route has just become dead. */
1220 res->nh_sel = 0;
1221 spin_unlock_bh(&fib_multipath_lock);
1222 }
1223 #endif
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