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[linux-2.6-block.git] / net / ipv4 / fib_semantics.c
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1da177e4
LT		 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 * Version: $Id: fib_semantics.c,v 1.19 2002/01/12 07:54:56 davem Exp $
9 *
10 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
1da177e4
LT		 18#include <asm/uaccess.h>
19#include <asm/system.h>
20#include <linux/bitops.h>
21#include <linux/types.h>
22#include <linux/kernel.h>
23#include <linux/jiffies.h>
24#include <linux/mm.h>
25#include <linux/string.h>
26#include <linux/socket.h>
27#include <linux/sockios.h>
28#include <linux/errno.h>
29#include <linux/in.h>
30#include <linux/inet.h>
14c85021 31#include <linux/inetdevice.h>
1da177e4
LT		 32#include <linux/netdevice.h>
33#include <linux/if_arp.h>
34#include <linux/proc_fs.h>
35#include <linux/skbuff.h>
36#include <linux/netlink.h>
37#include <linux/init.h>
38
14c85021 39#include <net/arp.h>
1da177e4
LT		 40#include <net/ip.h>
41#include <net/protocol.h>
42#include <net/route.h>
43#include <net/tcp.h>
44#include <net/sock.h>
45#include <net/ip_fib.h>
46#include <net/ip_mp_alg.h>
47
48#include "fib_lookup.h"
49
50#define FSprintk(a...)
51
52static DEFINE_RWLOCK(fib_info_lock);
53static struct hlist_head *fib_info_hash;
54static struct hlist_head *fib_info_laddrhash;
55static unsigned int fib_hash_size;
56static unsigned int fib_info_cnt;
57
58#define DEVINDEX_HASHBITS 8
59#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
60static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
61
62#ifdef CONFIG_IP_ROUTE_MULTIPATH
63
64static DEFINE_SPINLOCK(fib_multipath_lock);
65
66#define for_nexthops(fi) { int nhsel; const struct fib_nh * nh; \
67for (nhsel=0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
68
69#define change_nexthops(fi) { int nhsel; struct fib_nh * nh; \
70for (nhsel=0, nh = (struct fib_nh*)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++, nhsel++)
71
72#else /* CONFIG_IP_ROUTE_MULTIPATH */
73
74/* Hope, that gcc will optimize it to get rid of dummy loop */
75
76#define for_nexthops(fi) { int nhsel=0; const struct fib_nh * nh = (fi)->fib_nh; \
77for (nhsel=0; nhsel < 1; nhsel++)
78
79#define change_nexthops(fi) { int nhsel=0; struct fib_nh * nh = (struct fib_nh*)((fi)->fib_nh); \
80for (nhsel=0; nhsel < 1; nhsel++)
81
82#endif /* CONFIG_IP_ROUTE_MULTIPATH */
83
84#define endfor_nexthops(fi) }
85
86
9b5b5cff 87static const struct
1da177e4
LT		 88{
89 int error;
90 u8 scope;
91} fib_props[RTA_MAX + 1] = {
92 {
93 .error = 0,
94 .scope = RT_SCOPE_NOWHERE,
95 }, /* RTN_UNSPEC */
96 {
97 .error = 0,
98 .scope = RT_SCOPE_UNIVERSE,
99 }, /* RTN_UNICAST */
100 {
101 .error = 0,
102 .scope = RT_SCOPE_HOST,
103 }, /* RTN_LOCAL */
104 {
105 .error = 0,
106 .scope = RT_SCOPE_LINK,
107 }, /* RTN_BROADCAST */
108 {
109 .error = 0,
110 .scope = RT_SCOPE_LINK,
111 }, /* RTN_ANYCAST */
112 {
113 .error = 0,
114 .scope = RT_SCOPE_UNIVERSE,
115 }, /* RTN_MULTICAST */
116 {
117 .error = -EINVAL,
118 .scope = RT_SCOPE_UNIVERSE,
119 }, /* RTN_BLACKHOLE */
120 {
121 .error = -EHOSTUNREACH,
122 .scope = RT_SCOPE_UNIVERSE,
123 }, /* RTN_UNREACHABLE */
124 {
125 .error = -EACCES,
126 .scope = RT_SCOPE_UNIVERSE,
127 }, /* RTN_PROHIBIT */
128 {
129 .error = -EAGAIN,
130 .scope = RT_SCOPE_UNIVERSE,
131 }, /* RTN_THROW */
132 {
133 .error = -EINVAL,
134 .scope = RT_SCOPE_NOWHERE,
135 }, /* RTN_NAT */
136 {
137 .error = -EINVAL,
138 .scope = RT_SCOPE_NOWHERE,
139 }, /* RTN_XRESOLVE */
140};
141
142
143/* Release a nexthop info record */
144
145void free_fib_info(struct fib_info *fi)
146{
147 if (fi->fib_dead == 0) {
148 printk("Freeing alive fib_info %p\n", fi);
149 return;
150 }
151 change_nexthops(fi) {
152 if (nh->nh_dev)
153 dev_put(nh->nh_dev);
154 nh->nh_dev = NULL;
155 } endfor_nexthops(fi);
156 fib_info_cnt--;
157 kfree(fi);
158}
159
160void fib_release_info(struct fib_info *fi)
161{
162 write_lock(&fib_info_lock);
163 if (fi && --fi->fib_treeref == 0) {
164 hlist_del(&fi->fib_hash);
165 if (fi->fib_prefsrc)
166 hlist_del(&fi->fib_lhash);
167 change_nexthops(fi) {
168 if (!nh->nh_dev)
169 continue;
170 hlist_del(&nh->nh_hash);
171 } endfor_nexthops(fi)
172 fi->fib_dead = 1;
173 fib_info_put(fi);
174 }
175 write_unlock(&fib_info_lock);
176}
177
178static __inline__ int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
179{
180 const struct fib_nh *onh = ofi->fib_nh;
181
182 for_nexthops(fi) {
183 if (nh->nh_oif != onh->nh_oif ||
184 nh->nh_gw != onh->nh_gw ||
185 nh->nh_scope != onh->nh_scope ||
186#ifdef CONFIG_IP_ROUTE_MULTIPATH
187 nh->nh_weight != onh->nh_weight ||
188#endif
189#ifdef CONFIG_NET_CLS_ROUTE
190 nh->nh_tclassid != onh->nh_tclassid ||
191#endif
192 ((nh->nh_flags^onh->nh_flags)&~RTNH_F_DEAD))
193 return -1;
194 onh++;
195 } endfor_nexthops(fi);
196 return 0;
197}
198
199static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
200{
201 unsigned int mask = (fib_hash_size - 1);
202 unsigned int val = fi->fib_nhs;
203
204 val ^= fi->fib_protocol;
205 val ^= fi->fib_prefsrc;
206 val ^= fi->fib_priority;
207
208 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
209}
210
211static struct fib_info *fib_find_info(const struct fib_info *nfi)
212{
213 struct hlist_head *head;
214 struct hlist_node *node;
215 struct fib_info *fi;
216 unsigned int hash;
217
218 hash = fib_info_hashfn(nfi);
219 head = &fib_info_hash[hash];
220
221 hlist_for_each_entry(fi, node, head, fib_hash) {
222 if (fi->fib_nhs != nfi->fib_nhs)
223 continue;
224 if (nfi->fib_protocol == fi->fib_protocol &&
225 nfi->fib_prefsrc == fi->fib_prefsrc &&
226 nfi->fib_priority == fi->fib_priority &&
227 memcmp(nfi->fib_metrics, fi->fib_metrics,
228 sizeof(fi->fib_metrics)) == 0 &&
229 ((nfi->fib_flags^fi->fib_flags)&~RTNH_F_DEAD) == 0 &&
230 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
231 return fi;
232 }
233
234 return NULL;
235}
236
237static inline unsigned int fib_devindex_hashfn(unsigned int val)
238{
239 unsigned int mask = DEVINDEX_HASHSIZE - 1;
240
241 return (val ^
242 (val >> DEVINDEX_HASHBITS) ^
243 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
244}
245
246/* Check, that the gateway is already configured.
247 Used only by redirect accept routine.
248 */
249
250int ip_fib_check_default(u32 gw, struct net_device *dev)
251{
252 struct hlist_head *head;
253 struct hlist_node *node;
254 struct fib_nh *nh;
255 unsigned int hash;
256
257 read_lock(&fib_info_lock);
258
259 hash = fib_devindex_hashfn(dev->ifindex);
260 head = &fib_info_devhash[hash];
261 hlist_for_each_entry(nh, node, head, nh_hash) {
262 if (nh->nh_dev == dev &&
263 nh->nh_gw == gw &&
264 !(nh->nh_flags&RTNH_F_DEAD)) {
265 read_unlock(&fib_info_lock);
266 return 0;
267 }
268 }
269
270 read_unlock(&fib_info_lock);
271
272 return -1;
273}
274
275void rtmsg_fib(int event, u32 key, struct fib_alias *fa,
276 int z, int tb_id,
277 struct nlmsghdr *n, struct netlink_skb_parms *req)
278{
279 struct sk_buff *skb;
9ed19f33 280 u32 pid = req ? req->pid : n->nlmsg_pid;
1da177e4
LT		 281 int size = NLMSG_SPACE(sizeof(struct rtmsg)+256);
282
283 skb = alloc_skb(size, GFP_KERNEL);
284 if (!skb)
285 return;
286
287 if (fib_dump_info(skb, pid, n->nlmsg_seq, event, tb_id,
288 fa->fa_type, fa->fa_scope, &key, z,
289 fa->fa_tos,
b6544c0b 290 fa->fa_info, 0) < 0) {
1da177e4
LT		 291 kfree_skb(skb);
292 return;
293 }
ac6d439d 294 NETLINK_CB(skb).dst_group = RTNLGRP_IPV4_ROUTE;
1da177e4
LT		 295 if (n->nlmsg_flags&NLM_F_ECHO)
296 atomic_inc(&skb->users);
ac6d439d 297 netlink_broadcast(rtnl, skb, pid, RTNLGRP_IPV4_ROUTE, GFP_KERNEL);
1da177e4
LT		 298 if (n->nlmsg_flags&NLM_F_ECHO)
299 netlink_unicast(rtnl, skb, pid, MSG_DONTWAIT);
300}
301
302/* Return the first fib alias matching TOS with
303 * priority less than or equal to PRIO.
304 */
305struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
306{
307 if (fah) {
308 struct fib_alias *fa;
309 list_for_each_entry(fa, fah, fa_list) {
310 if (fa->fa_tos > tos)
311 continue;
312 if (fa->fa_info->fib_priority >= prio ||
313 fa->fa_tos < tos)
314 return fa;
315 }
316 }
317 return NULL;
318}
319
320int fib_detect_death(struct fib_info *fi, int order,
321 struct fib_info **last_resort, int *last_idx, int *dflt)
322{
323 struct neighbour *n;
324 int state = NUD_NONE;
325
326 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
327 if (n) {
328 state = n->nud_state;
329 neigh_release(n);
330 }
331 if (state==NUD_REACHABLE)
332 return 0;
333 if ((state&NUD_VALID) && order != *dflt)
334 return 0;
335 if ((state&NUD_VALID) ||
336 (*last_idx<0 && order > *dflt)) {
337 *last_resort = fi;
338 *last_idx = order;
339 }
340 return 1;
341}
342
343#ifdef CONFIG_IP_ROUTE_MULTIPATH
344
345static u32 fib_get_attr32(struct rtattr *attr, int attrlen, int type)
346{
347 while (RTA_OK(attr,attrlen)) {
348 if (attr->rta_type == type)
349 return *(u32*)RTA_DATA(attr);
350 attr = RTA_NEXT(attr, attrlen);
351 }
352 return 0;
353}
354
355static int
356fib_count_nexthops(struct rtattr *rta)
357{
358 int nhs = 0;
359 struct rtnexthop *nhp = RTA_DATA(rta);
360 int nhlen = RTA_PAYLOAD(rta);
361
362 while (nhlen >= (int)sizeof(struct rtnexthop)) {
363 if ((nhlen -= nhp->rtnh_len) < 0)
364 return 0;
365 nhs++;
366 nhp = RTNH_NEXT(nhp);
367 };
368 return nhs;
369}
370
371static int
372fib_get_nhs(struct fib_info *fi, const struct rtattr *rta, const struct rtmsg *r)
373{
374 struct rtnexthop *nhp = RTA_DATA(rta);
375 int nhlen = RTA_PAYLOAD(rta);
376
377 change_nexthops(fi) {
378 int attrlen = nhlen - sizeof(struct rtnexthop);
379 if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
380 return -EINVAL;
381 nh->nh_flags = (r->rtm_flags&~0xFF) | nhp->rtnh_flags;
382 nh->nh_oif = nhp->rtnh_ifindex;
383 nh->nh_weight = nhp->rtnh_hops + 1;
384 if (attrlen) {
385 nh->nh_gw = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
386#ifdef CONFIG_NET_CLS_ROUTE
387 nh->nh_tclassid = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_FLOW);
388#endif
389 }
390 nhp = RTNH_NEXT(nhp);
391 } endfor_nexthops(fi);
392 return 0;
393}
394
395#endif
396
397int fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct kern_rta *rta,
398 struct fib_info *fi)
399{
400#ifdef CONFIG_IP_ROUTE_MULTIPATH
401 struct rtnexthop *nhp;
402 int nhlen;
403#endif
404
405 if (rta->rta_priority &&
406 *rta->rta_priority != fi->fib_priority)
407 return 1;
408
409 if (rta->rta_oif || rta->rta_gw) {
410 if ((!rta->rta_oif || *rta->rta_oif == fi->fib_nh->nh_oif) &&
411 (!rta->rta_gw || memcmp(rta->rta_gw, &fi->fib_nh->nh_gw, 4) == 0))
412 return 0;
413 return 1;
414 }
415
416#ifdef CONFIG_IP_ROUTE_MULTIPATH
417 if (rta->rta_mp == NULL)
418 return 0;
419 nhp = RTA_DATA(rta->rta_mp);
420 nhlen = RTA_PAYLOAD(rta->rta_mp);
421
422 for_nexthops(fi) {
423 int attrlen = nhlen - sizeof(struct rtnexthop);
424 u32 gw;
425
426 if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
427 return -EINVAL;
428 if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
429 return 1;
430 if (attrlen) {
431 gw = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
432 if (gw && gw != nh->nh_gw)
433 return 1;
434#ifdef CONFIG_NET_CLS_ROUTE
435 gw = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_FLOW);
436 if (gw && gw != nh->nh_tclassid)
437 return 1;
438#endif
439 }
440 nhp = RTNH_NEXT(nhp);
441 } endfor_nexthops(fi);
442#endif
443 return 0;
444}
445
446
447/*
448 Picture
449 -------
450
451 Semantics of nexthop is very messy by historical reasons.
452 We have to take into account, that:
453 a) gateway can be actually local interface address,
454 so that gatewayed route is direct.
455 b) gateway must be on-link address, possibly
456 described not by an ifaddr, but also by a direct route.
457 c) If both gateway and interface are specified, they should not
458 contradict.
459 d) If we use tunnel routes, gateway could be not on-link.
460
461 Attempt to reconcile all of these (alas, self-contradictory) conditions
462 results in pretty ugly and hairy code with obscure logic.
463
464 I chose to generalized it instead, so that the size
465 of code does not increase practically, but it becomes
466 much more general.
467 Every prefix is assigned a "scope" value: "host" is local address,
468 "link" is direct route,
469 [ ... "site" ... "interior" ... ]
470 and "universe" is true gateway route with global meaning.
471
472 Every prefix refers to a set of "nexthop"s (gw, oif),
473 where gw must have narrower scope. This recursion stops
474 when gw has LOCAL scope or if "nexthop" is declared ONLINK,
475 which means that gw is forced to be on link.
476
477 Code is still hairy, but now it is apparently logically
478 consistent and very flexible. F.e. as by-product it allows
479 to co-exists in peace independent exterior and interior
480 routing processes.
481
482 Normally it looks as following.
483
484 {universe prefix} -> (gw, oif) [scope link]
485 |
486 |-> {link prefix} -> (gw, oif) [scope local]
487 |
488 |-> {local prefix} (terminal node)
489 */
490
491static int fib_check_nh(const struct rtmsg *r, struct fib_info *fi, struct fib_nh *nh)
492{
493 int err;
494
495 if (nh->nh_gw) {
496 struct fib_result res;
497
498#ifdef CONFIG_IP_ROUTE_PERVASIVE
499 if (nh->nh_flags&RTNH_F_PERVASIVE)
500 return 0;
501#endif
502 if (nh->nh_flags&RTNH_F_ONLINK) {
503 struct net_device *dev;
504
505 if (r->rtm_scope >= RT_SCOPE_LINK)
506 return -EINVAL;
507 if (inet_addr_type(nh->nh_gw) != RTN_UNICAST)
508 return -EINVAL;
509 if ((dev = __dev_get_by_index(nh->nh_oif)) == NULL)
510 return -ENODEV;
511 if (!(dev->flags&IFF_UP))
512 return -ENETDOWN;
513 nh->nh_dev = dev;
514 dev_hold(dev);
515 nh->nh_scope = RT_SCOPE_LINK;
516 return 0;
517 }
518 {
519 struct flowi fl = { .nl_u = { .ip4_u =
520 { .daddr = nh->nh_gw,
521 .scope = r->rtm_scope + 1 } },
522 .oif = nh->nh_oif };
523
524 /* It is not necessary, but requires a bit of thinking */
525 if (fl.fl4_scope < RT_SCOPE_LINK)
526 fl.fl4_scope = RT_SCOPE_LINK;
527 if ((err = fib_lookup(&fl, &res)) != 0)
528 return err;
529 }
530 err = -EINVAL;
531 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
532 goto out;
533 nh->nh_scope = res.scope;
534 nh->nh_oif = FIB_RES_OIF(res);
535 if ((nh->nh_dev = FIB_RES_DEV(res)) == NULL)
536 goto out;
537 dev_hold(nh->nh_dev);
538 err = -ENETDOWN;
539 if (!(nh->nh_dev->flags & IFF_UP))
540 goto out;
541 err = 0;
542out:
543 fib_res_put(&res);
544 return err;
545 } else {
546 struct in_device *in_dev;
547
548 if (nh->nh_flags&(RTNH_F_PERVASIVE|RTNH_F_ONLINK))
549 return -EINVAL;
550
551 in_dev = inetdev_by_index(nh->nh_oif);
552 if (in_dev == NULL)
553 return -ENODEV;
554 if (!(in_dev->dev->flags&IFF_UP)) {
555 in_dev_put(in_dev);
556 return -ENETDOWN;
557 }
558 nh->nh_dev = in_dev->dev;
559 dev_hold(nh->nh_dev);
560 nh->nh_scope = RT_SCOPE_HOST;
561 in_dev_put(in_dev);
562 }
563 return 0;
564}
565
566static inline unsigned int fib_laddr_hashfn(u32 val)
567{
568 unsigned int mask = (fib_hash_size - 1);
569
570 return (val ^ (val >> 7) ^ (val >> 14)) & mask;
571}
572
573static struct hlist_head *fib_hash_alloc(int bytes)
574{
575 if (bytes <= PAGE_SIZE)
576 return kmalloc(bytes, GFP_KERNEL);
577 else
578 return (struct hlist_head *)
579 __get_free_pages(GFP_KERNEL, get_order(bytes));
580}
581
582static void fib_hash_free(struct hlist_head *hash, int bytes)
583{
584 if (!hash)
585 return;
586
587 if (bytes <= PAGE_SIZE)
588 kfree(hash);
589 else
590 free_pages((unsigned long) hash, get_order(bytes));
591}
592
593static void fib_hash_move(struct hlist_head *new_info_hash,
594 struct hlist_head *new_laddrhash,
595 unsigned int new_size)
596{
b7656e7f 597 struct hlist_head *old_info_hash, *old_laddrhash;
1da177e4 598 unsigned int old_size = fib_hash_size;
b7656e7f 599 unsigned int i, bytes;
1da177e4
LT		 600
601 write_lock(&fib_info_lock);
b7656e7f
DM		 602 old_info_hash = fib_info_hash;
603 old_laddrhash = fib_info_laddrhash;
1da177e4
LT		 604 fib_hash_size = new_size;
605
606 for (i = 0; i < old_size; i++) {
607 struct hlist_head *head = &fib_info_hash[i];
608 struct hlist_node *node, *n;
609 struct fib_info *fi;
610
611 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
612 struct hlist_head *dest;
613 unsigned int new_hash;
614
615 hlist_del(&fi->fib_hash);
616
617 new_hash = fib_info_hashfn(fi);
618 dest = &new_info_hash[new_hash];
619 hlist_add_head(&fi->fib_hash, dest);
620 }
621 }
622 fib_info_hash = new_info_hash;
623
624 for (i = 0; i < old_size; i++) {
625 struct hlist_head *lhead = &fib_info_laddrhash[i];
626 struct hlist_node *node, *n;
627 struct fib_info *fi;
628
629 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
630 struct hlist_head *ldest;
631 unsigned int new_hash;
632
633 hlist_del(&fi->fib_lhash);
634
635 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
636 ldest = &new_laddrhash[new_hash];
637 hlist_add_head(&fi->fib_lhash, ldest);
638 }
639 }
640 fib_info_laddrhash = new_laddrhash;
641
642 write_unlock(&fib_info_lock);
b7656e7f
DM		 643
644 bytes = old_size * sizeof(struct hlist_head *);
645 fib_hash_free(old_info_hash, bytes);
646 fib_hash_free(old_laddrhash, bytes);
1da177e4
LT		 647}
648
649struct fib_info *
650fib_create_info(const struct rtmsg *r, struct kern_rta *rta,
651 const struct nlmsghdr *nlh, int *errp)
652{
653 int err;
654 struct fib_info *fi = NULL;
655 struct fib_info *ofi;
656#ifdef CONFIG_IP_ROUTE_MULTIPATH
657 int nhs = 1;
658#else
659 const int nhs = 1;
660#endif
661#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
662 u32 mp_alg = IP_MP_ALG_NONE;
663#endif
664
665 /* Fast check to catch the most weird cases */
666 if (fib_props[r->rtm_type].scope > r->rtm_scope)
667 goto err_inval;
668
669#ifdef CONFIG_IP_ROUTE_MULTIPATH
670 if (rta->rta_mp) {
671 nhs = fib_count_nexthops(rta->rta_mp);
672 if (nhs == 0)
673 goto err_inval;
674 }
675#endif
676#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
677 if (rta->rta_mp_alg) {
678 mp_alg = *rta->rta_mp_alg;
679
680 if (mp_alg < IP_MP_ALG_NONE ||
681 mp_alg > IP_MP_ALG_MAX)
682 goto err_inval;
683 }
684#endif
685
686 err = -ENOBUFS;
687 if (fib_info_cnt >= fib_hash_size) {
688 unsigned int new_size = fib_hash_size << 1;
689 struct hlist_head *new_info_hash;
690 struct hlist_head *new_laddrhash;
691 unsigned int bytes;
692
693 if (!new_size)
694 new_size = 1;
695 bytes = new_size * sizeof(struct hlist_head *);
696 new_info_hash = fib_hash_alloc(bytes);
697 new_laddrhash = fib_hash_alloc(bytes);
698 if (!new_info_hash || !new_laddrhash) {
699 fib_hash_free(new_info_hash, bytes);
700 fib_hash_free(new_laddrhash, bytes);
701 } else {
702 memset(new_info_hash, 0, bytes);
703 memset(new_laddrhash, 0, bytes);
704
705 fib_hash_move(new_info_hash, new_laddrhash, new_size);
706 }
707
708 if (!fib_hash_size)
709 goto failure;
710 }
711
712 fi = kmalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
713 if (fi == NULL)
714 goto failure;
715 fib_info_cnt++;
716 memset(fi, 0, sizeof(*fi)+nhs*sizeof(struct fib_nh));
717
718 fi->fib_protocol = r->rtm_protocol;
719
720 fi->fib_nhs = nhs;
721 change_nexthops(fi) {
722 nh->nh_parent = fi;
723 } endfor_nexthops(fi)
724
725 fi->fib_flags = r->rtm_flags;
726 if (rta->rta_priority)
727 fi->fib_priority = *rta->rta_priority;
728 if (rta->rta_mx) {
729 int attrlen = RTA_PAYLOAD(rta->rta_mx);
730 struct rtattr *attr = RTA_DATA(rta->rta_mx);
731
732 while (RTA_OK(attr, attrlen)) {
733 unsigned flavor = attr->rta_type;
734 if (flavor) {
735 if (flavor > RTAX_MAX)
736 goto err_inval;
737 fi->fib_metrics[flavor-1] = *(unsigned*)RTA_DATA(attr);
738 }
739 attr = RTA_NEXT(attr, attrlen);
740 }
741 }
742 if (rta->rta_prefsrc)
743 memcpy(&fi->fib_prefsrc, rta->rta_prefsrc, 4);
744
745 if (rta->rta_mp) {
746#ifdef CONFIG_IP_ROUTE_MULTIPATH
747 if ((err = fib_get_nhs(fi, rta->rta_mp, r)) != 0)
748 goto failure;
749 if (rta->rta_oif && fi->fib_nh->nh_oif != *rta->rta_oif)
750 goto err_inval;
751 if (rta->rta_gw && memcmp(&fi->fib_nh->nh_gw, rta->rta_gw, 4))
752 goto err_inval;
753#ifdef CONFIG_NET_CLS_ROUTE
754 if (rta->rta_flow && memcmp(&fi->fib_nh->nh_tclassid, rta->rta_flow, 4))
755 goto err_inval;
756#endif
757#else
758 goto err_inval;
759#endif
760 } else {
761 struct fib_nh *nh = fi->fib_nh;
762 if (rta->rta_oif)
763 nh->nh_oif = *rta->rta_oif;
764 if (rta->rta_gw)
765 memcpy(&nh->nh_gw, rta->rta_gw, 4);
766#ifdef CONFIG_NET_CLS_ROUTE
767 if (rta->rta_flow)
768 memcpy(&nh->nh_tclassid, rta->rta_flow, 4);
769#endif
770 nh->nh_flags = r->rtm_flags;
771#ifdef CONFIG_IP_ROUTE_MULTIPATH
772 nh->nh_weight = 1;
773#endif
774 }
775
776#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
777 fi->fib_mp_alg = mp_alg;
778#endif
779
780 if (fib_props[r->rtm_type].error) {
781 if (rta->rta_gw || rta->rta_oif || rta->rta_mp)
782 goto err_inval;
783 goto link_it;
784 }
785
786 if (r->rtm_scope > RT_SCOPE_HOST)
787 goto err_inval;
788
789 if (r->rtm_scope == RT_SCOPE_HOST) {
790 struct fib_nh *nh = fi->fib_nh;
791
792 /* Local address is added. */
793 if (nhs != 1 || nh->nh_gw)
794 goto err_inval;
795 nh->nh_scope = RT_SCOPE_NOWHERE;
796 nh->nh_dev = dev_get_by_index(fi->fib_nh->nh_oif);
797 err = -ENODEV;
798 if (nh->nh_dev == NULL)
799 goto failure;
800 } else {
801 change_nexthops(fi) {
802 if ((err = fib_check_nh(r, fi, nh)) != 0)
803 goto failure;
804 } endfor_nexthops(fi)
805 }
806
807 if (fi->fib_prefsrc) {
808 if (r->rtm_type != RTN_LOCAL || rta->rta_dst == NULL ||
809 memcmp(&fi->fib_prefsrc, rta->rta_dst, 4))
810 if (inet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
811 goto err_inval;
812 }
813
814link_it:
815 if ((ofi = fib_find_info(fi)) != NULL) {
816 fi->fib_dead = 1;
817 free_fib_info(fi);
818 ofi->fib_treeref++;
819 return ofi;
820 }
821
822 fi->fib_treeref++;
823 atomic_inc(&fi->fib_clntref);
824 write_lock(&fib_info_lock);
825 hlist_add_head(&fi->fib_hash,
826 &fib_info_hash[fib_info_hashfn(fi)]);
827 if (fi->fib_prefsrc) {
828 struct hlist_head *head;
829
830 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
831 hlist_add_head(&fi->fib_lhash, head);
832 }
833 change_nexthops(fi) {
834 struct hlist_head *head;
835 unsigned int hash;
836
837 if (!nh->nh_dev)
838 continue;
839 hash = fib_devindex_hashfn(nh->nh_dev->ifindex);
840 head = &fib_info_devhash[hash];
841 hlist_add_head(&nh->nh_hash, head);
842 } endfor_nexthops(fi)
843 write_unlock(&fib_info_lock);
844 return fi;
845
846err_inval:
847 err = -EINVAL;
848
849failure:
850 *errp = err;
851 if (fi) {
852 fi->fib_dead = 1;
853 free_fib_info(fi);
854 }
855 return NULL;
856}
857
e5b43760 858/* Note! fib_semantic_match intentionally uses RCU list functions. */
1da177e4
LT		 859int fib_semantic_match(struct list_head *head, const struct flowi *flp,
860 struct fib_result *res, __u32 zone, __u32 mask,
861 int prefixlen)
862{
863 struct fib_alias *fa;
864 int nh_sel = 0;
865
e5b43760 866 list_for_each_entry_rcu(fa, head, fa_list) {
1da177e4
LT		 867 int err;
868
869 if (fa->fa_tos &&
870 fa->fa_tos != flp->fl4_tos)
871 continue;
872
873 if (fa->fa_scope < flp->fl4_scope)
874 continue;
875
876 fa->fa_state |= FA_S_ACCESSED;
877
878 err = fib_props[fa->fa_type].error;
879 if (err == 0) {
880 struct fib_info *fi = fa->fa_info;
881
882 if (fi->fib_flags & RTNH_F_DEAD)
883 continue;
884
885 switch (fa->fa_type) {
886 case RTN_UNICAST:
887 case RTN_LOCAL:
888 case RTN_BROADCAST:
889 case RTN_ANYCAST:
890 case RTN_MULTICAST:
891 for_nexthops(fi) {
892 if (nh->nh_flags&RTNH_F_DEAD)
893 continue;
894 if (!flp->oif || flp->oif == nh->nh_oif)
895 break;
896 }
897#ifdef CONFIG_IP_ROUTE_MULTIPATH
898 if (nhsel < fi->fib_nhs) {
899 nh_sel = nhsel;
900 goto out_fill_res;
901 }
902#else
903 if (nhsel < 1) {
904 goto out_fill_res;
905 }
906#endif
907 endfor_nexthops(fi);
908 continue;
909
910 default:
911 printk(KERN_DEBUG "impossible 102\n");
912 return -EINVAL;
913 };
914 }
915 return err;
916 }
917 return 1;
918
919out_fill_res:
920 res->prefixlen = prefixlen;
921 res->nh_sel = nh_sel;
922 res->type = fa->fa_type;
923 res->scope = fa->fa_scope;
924 res->fi = fa->fa_info;
925#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
926 res->netmask = mask;
927 res->network = zone &
928 (0xFFFFFFFF >> (32 - prefixlen));
929#endif
930 atomic_inc(&res->fi->fib_clntref);
931 return 0;
932}
933
934/* Find appropriate source address to this destination */
935
936u32 __fib_res_prefsrc(struct fib_result *res)
937{
938 return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
939}
940
941int
942fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
943 u8 tb_id, u8 type, u8 scope, void *dst, int dst_len, u8 tos,
b6544c0b 944 struct fib_info *fi, unsigned int flags)
1da177e4
LT		 945{
946 struct rtmsg *rtm;
947 struct nlmsghdr *nlh;
948 unsigned char *b = skb->tail;
949
b6544c0b 950 nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags);
1da177e4
LT		 951 rtm = NLMSG_DATA(nlh);
952 rtm->rtm_family = AF_INET;
953 rtm->rtm_dst_len = dst_len;
954 rtm->rtm_src_len = 0;
955 rtm->rtm_tos = tos;
956 rtm->rtm_table = tb_id;
957 rtm->rtm_type = type;
958 rtm->rtm_flags = fi->fib_flags;
959 rtm->rtm_scope = scope;
960 if (rtm->rtm_dst_len)
961 RTA_PUT(skb, RTA_DST, 4, dst);
962 rtm->rtm_protocol = fi->fib_protocol;
963 if (fi->fib_priority)
964 RTA_PUT(skb, RTA_PRIORITY, 4, &fi->fib_priority);
965#ifdef CONFIG_NET_CLS_ROUTE
966 if (fi->fib_nh[0].nh_tclassid)
967 RTA_PUT(skb, RTA_FLOW, 4, &fi->fib_nh[0].nh_tclassid);
968#endif
969 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
970 goto rtattr_failure;
971 if (fi->fib_prefsrc)
972 RTA_PUT(skb, RTA_PREFSRC, 4, &fi->fib_prefsrc);
973 if (fi->fib_nhs == 1) {
974 if (fi->fib_nh->nh_gw)
975 RTA_PUT(skb, RTA_GATEWAY, 4, &fi->fib_nh->nh_gw);
976 if (fi->fib_nh->nh_oif)
977 RTA_PUT(skb, RTA_OIF, sizeof(int), &fi->fib_nh->nh_oif);
978 }
979#ifdef CONFIG_IP_ROUTE_MULTIPATH
980 if (fi->fib_nhs > 1) {
981 struct rtnexthop *nhp;
982 struct rtattr *mp_head;
983 if (skb_tailroom(skb) <= RTA_SPACE(0))
984 goto rtattr_failure;
985 mp_head = (struct rtattr*)skb_put(skb, RTA_SPACE(0));
986
987 for_nexthops(fi) {
988 if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
989 goto rtattr_failure;
990 nhp = (struct rtnexthop*)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
991 nhp->rtnh_flags = nh->nh_flags & 0xFF;
992 nhp->rtnh_hops = nh->nh_weight-1;
993 nhp->rtnh_ifindex = nh->nh_oif;
994 if (nh->nh_gw)
995 RTA_PUT(skb, RTA_GATEWAY, 4, &nh->nh_gw);
996 nhp->rtnh_len = skb->tail - (unsigned char*)nhp;
997 } endfor_nexthops(fi);
998 mp_head->rta_type = RTA_MULTIPATH;
999 mp_head->rta_len = skb->tail - (u8*)mp_head;
1000 }
1001#endif
1002 nlh->nlmsg_len = skb->tail - b;
1003 return skb->len;
1004
1005nlmsg_failure:
1006rtattr_failure:
1007 skb_trim(skb, b - skb->data);
1008 return -1;
1009}
1010
1011#ifndef CONFIG_IP_NOSIOCRT
1012
1013int
1014fib_convert_rtentry(int cmd, struct nlmsghdr *nl, struct rtmsg *rtm,
1015 struct kern_rta *rta, struct rtentry *r)
1016{
1017 int plen;
1018 u32 *ptr;
1019
1020 memset(rtm, 0, sizeof(*rtm));
1021 memset(rta, 0, sizeof(*rta));
1022
1023 if (r->rt_dst.sa_family != AF_INET)
1024 return -EAFNOSUPPORT;
1025
1026 /* Check mask for validity:
1027 a) it must be contiguous.
1028 b) destination must have all host bits clear.
1029 c) if application forgot to set correct family (AF_INET),
1030 reject request unless it is absolutely clear i.e.
1031 both family and mask are zero.
1032 */
1033 plen = 32;
1034 ptr = &((struct sockaddr_in*)&r->rt_dst)->sin_addr.s_addr;
1035 if (!(r->rt_flags&RTF_HOST)) {
1036 u32 mask = ((struct sockaddr_in*)&r->rt_genmask)->sin_addr.s_addr;
1037 if (r->rt_genmask.sa_family != AF_INET) {
1038 if (mask || r->rt_genmask.sa_family)
1039 return -EAFNOSUPPORT;
1040 }
1041 if (bad_mask(mask, *ptr))
1042 return -EINVAL;
1043 plen = inet_mask_len(mask);
1044 }
1045
1046 nl->nlmsg_flags = NLM_F_REQUEST;
28633514 1047 nl->nlmsg_pid = 0;
1da177e4
LT		 1048 nl->nlmsg_seq = 0;
1049 nl->nlmsg_len = NLMSG_LENGTH(sizeof(*rtm));
1050 if (cmd == SIOCDELRT) {
1051 nl->nlmsg_type = RTM_DELROUTE;
1052 nl->nlmsg_flags = 0;
1053 } else {
1054 nl->nlmsg_type = RTM_NEWROUTE;
1055 nl->nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE;
1056 rtm->rtm_protocol = RTPROT_BOOT;
1057 }
1058
1059 rtm->rtm_dst_len = plen;
1060 rta->rta_dst = ptr;
1061
1062 if (r->rt_metric) {
1063 *(u32*)&r->rt_pad3 = r->rt_metric - 1;
1064 rta->rta_priority = (u32*)&r->rt_pad3;
1065 }
1066 if (r->rt_flags&RTF_REJECT) {
1067 rtm->rtm_scope = RT_SCOPE_HOST;
1068 rtm->rtm_type = RTN_UNREACHABLE;
1069 return 0;
1070 }
1071 rtm->rtm_scope = RT_SCOPE_NOWHERE;
1072 rtm->rtm_type = RTN_UNICAST;
1073
1074 if (r->rt_dev) {
1075 char *colon;
1076 struct net_device *dev;
1077 char devname[IFNAMSIZ];
1078
1079 if (copy_from_user(devname, r->rt_dev, IFNAMSIZ-1))
1080 return -EFAULT;
1081 devname[IFNAMSIZ-1] = 0;
1082 colon = strchr(devname, ':');
1083 if (colon)
1084 *colon = 0;
1085 dev = __dev_get_by_name(devname);
1086 if (!dev)
1087 return -ENODEV;
1088 rta->rta_oif = &dev->ifindex;
1089 if (colon) {
1090 struct in_ifaddr *ifa;
e5ed6399 1091 struct in_device *in_dev = __in_dev_get_rtnl(dev);
1da177e4
LT		 1092 if (!in_dev)
1093 return -ENODEV;
1094 *colon = ':';
1095 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
1096 if (strcmp(ifa->ifa_label, devname) == 0)
1097 break;
1098 if (ifa == NULL)
1099 return -ENODEV;
1100 rta->rta_prefsrc = &ifa->ifa_local;
1101 }
1102 }
1103
1104 ptr = &((struct sockaddr_in*)&r->rt_gateway)->sin_addr.s_addr;
1105 if (r->rt_gateway.sa_family == AF_INET && *ptr) {
1106 rta->rta_gw = ptr;
1107 if (r->rt_flags&RTF_GATEWAY && inet_addr_type(*ptr) == RTN_UNICAST)
1108 rtm->rtm_scope = RT_SCOPE_UNIVERSE;
1109 }
1110
1111 if (cmd == SIOCDELRT)
1112 return 0;
1113
1114 if (r->rt_flags&RTF_GATEWAY && rta->rta_gw == NULL)
1115 return -EINVAL;
1116
1117 if (rtm->rtm_scope == RT_SCOPE_NOWHERE)
1118 rtm->rtm_scope = RT_SCOPE_LINK;
1119
1120 if (r->rt_flags&(RTF_MTU|RTF_WINDOW|RTF_IRTT)) {
1121 struct rtattr *rec;
1122 struct rtattr *mx = kmalloc(RTA_LENGTH(3*RTA_LENGTH(4)), GFP_KERNEL);
1123 if (mx == NULL)
1124 return -ENOMEM;
1125 rta->rta_mx = mx;
1126 mx->rta_type = RTA_METRICS;
1127 mx->rta_len = RTA_LENGTH(0);
1128 if (r->rt_flags&RTF_MTU) {
1129 rec = (void*)((char*)mx + RTA_ALIGN(mx->rta_len));
1130 rec->rta_type = RTAX_ADVMSS;
1131 rec->rta_len = RTA_LENGTH(4);
1132 mx->rta_len += RTA_LENGTH(4);
1133 *(u32*)RTA_DATA(rec) = r->rt_mtu - 40;
1134 }
1135 if (r->rt_flags&RTF_WINDOW) {
1136 rec = (void*)((char*)mx + RTA_ALIGN(mx->rta_len));
1137 rec->rta_type = RTAX_WINDOW;
1138 rec->rta_len = RTA_LENGTH(4);
1139 mx->rta_len += RTA_LENGTH(4);
1140 *(u32*)RTA_DATA(rec) = r->rt_window;
1141 }
1142 if (r->rt_flags&RTF_IRTT) {
1143 rec = (void*)((char*)mx + RTA_ALIGN(mx->rta_len));
1144 rec->rta_type = RTAX_RTT;
1145 rec->rta_len = RTA_LENGTH(4);
1146 mx->rta_len += RTA_LENGTH(4);
1147 *(u32*)RTA_DATA(rec) = r->rt_irtt<<3;
1148 }
1149 }
1150 return 0;
1151}
1152
1153#endif
1154
1155/*
1156 Update FIB if:
1157 - local address disappeared -> we must delete all the entries
1158 referring to it.
1159 - device went down -> we must shutdown all nexthops going via it.
1160 */
1161
1162int fib_sync_down(u32 local, struct net_device *dev, int force)
1163{
1164 int ret = 0;
1165 int scope = RT_SCOPE_NOWHERE;
1166
1167 if (force)
1168 scope = -1;
1169
1170 if (local && fib_info_laddrhash) {
1171 unsigned int hash = fib_laddr_hashfn(local);
1172 struct hlist_head *head = &fib_info_laddrhash[hash];
1173 struct hlist_node *node;
1174 struct fib_info *fi;
1175
1176 hlist_for_each_entry(fi, node, head, fib_lhash) {
1177 if (fi->fib_prefsrc == local) {
1178 fi->fib_flags |= RTNH_F_DEAD;
1179 ret++;
1180 }
1181 }
1182 }
1183
1184 if (dev) {
1185 struct fib_info *prev_fi = NULL;
1186 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1187 struct hlist_head *head = &fib_info_devhash[hash];
1188 struct hlist_node *node;
1189 struct fib_nh *nh;
1190
1191 hlist_for_each_entry(nh, node, head, nh_hash) {
1192 struct fib_info *fi = nh->nh_parent;
1193 int dead;
1194
1195 BUG_ON(!fi->fib_nhs);
1196 if (nh->nh_dev != dev || fi == prev_fi)
1197 continue;
1198 prev_fi = fi;
1199 dead = 0;
1200 change_nexthops(fi) {
1201 if (nh->nh_flags&RTNH_F_DEAD)
1202 dead++;
1203 else if (nh->nh_dev == dev &&
1204 nh->nh_scope != scope) {
1205 nh->nh_flags |= RTNH_F_DEAD;
1206#ifdef CONFIG_IP_ROUTE_MULTIPATH
1207 spin_lock_bh(&fib_multipath_lock);
1208 fi->fib_power -= nh->nh_power;
1209 nh->nh_power = 0;
1210 spin_unlock_bh(&fib_multipath_lock);
1211#endif
1212 dead++;
1213 }
1214#ifdef CONFIG_IP_ROUTE_MULTIPATH
1215 if (force > 1 && nh->nh_dev == dev) {
1216 dead = fi->fib_nhs;
1217 break;
1218 }
1219#endif
1220 } endfor_nexthops(fi)
1221 if (dead == fi->fib_nhs) {
1222 fi->fib_flags |= RTNH_F_DEAD;
1223 ret++;
1224 }
1225 }
1226 }
1227
1228 return ret;
1229}
1230
1231#ifdef CONFIG_IP_ROUTE_MULTIPATH
1232
1233/*
1234 Dead device goes up. We wake up dead nexthops.
1235 It takes sense only on multipath routes.
1236 */
1237
1238int fib_sync_up(struct net_device *dev)
1239{
1240 struct fib_info *prev_fi;
1241 unsigned int hash;
1242 struct hlist_head *head;
1243 struct hlist_node *node;
1244 struct fib_nh *nh;
1245 int ret;
1246
1247 if (!(dev->flags&IFF_UP))
1248 return 0;
1249
1250 prev_fi = NULL;
1251 hash = fib_devindex_hashfn(dev->ifindex);
1252 head = &fib_info_devhash[hash];
1253 ret = 0;
1254
1255 hlist_for_each_entry(nh, node, head, nh_hash) {
1256 struct fib_info *fi = nh->nh_parent;
1257 int alive;
1258
1259 BUG_ON(!fi->fib_nhs);
1260 if (nh->nh_dev != dev || fi == prev_fi)
1261 continue;
1262
1263 prev_fi = fi;
1264 alive = 0;
1265 change_nexthops(fi) {
1266 if (!(nh->nh_flags&RTNH_F_DEAD)) {
1267 alive++;
1268 continue;
1269 }
1270 if (nh->nh_dev == NULL || !(nh->nh_dev->flags&IFF_UP))
1271 continue;
e5ed6399 1272 if (nh->nh_dev != dev || !__in_dev_get_rtnl(dev))
1da177e4
LT		 1273 continue;
1274 alive++;
1275 spin_lock_bh(&fib_multipath_lock);
1276 nh->nh_power = 0;
1277 nh->nh_flags &= ~RTNH_F_DEAD;
1278 spin_unlock_bh(&fib_multipath_lock);
1279 } endfor_nexthops(fi)
1280
1281 if (alive > 0) {
1282 fi->fib_flags &= ~RTNH_F_DEAD;
1283 ret++;
1284 }
1285 }
1286
1287 return ret;
1288}
1289
1290/*
1291 The algorithm is suboptimal, but it provides really
1292 fair weighted route distribution.
1293 */
1294
1295void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
1296{
1297 struct fib_info *fi = res->fi;
1298 int w;
1299
1300 spin_lock_bh(&fib_multipath_lock);
1301 if (fi->fib_power <= 0) {
1302 int power = 0;
1303 change_nexthops(fi) {
1304 if (!(nh->nh_flags&RTNH_F_DEAD)) {
1305 power += nh->nh_weight;
1306 nh->nh_power = nh->nh_weight;
1307 }
1308 } endfor_nexthops(fi);
1309 fi->fib_power = power;
1310 if (power <= 0) {
1311 spin_unlock_bh(&fib_multipath_lock);
1312 /* Race condition: route has just become dead. */
1313 res->nh_sel = 0;
1314 return;
1315 }
1316 }
1317
1318
1319 /* w should be random number [0..fi->fib_power-1],
1320 it is pretty bad approximation.
1321 */
1322
1323 w = jiffies % fi->fib_power;
1324
1325 change_nexthops(fi) {
1326 if (!(nh->nh_flags&RTNH_F_DEAD) && nh->nh_power) {
1327 if ((w -= nh->nh_power) <= 0) {
1328 nh->nh_power--;
1329 fi->fib_power--;
1330 res->nh_sel = nhsel;
1331 spin_unlock_bh(&fib_multipath_lock);
1332 return;
1333 }
1334 }
1335 } endfor_nexthops(fi);
1336
1337 /* Race condition: route has just become dead. */
1338 res->nh_sel = 0;
1339 spin_unlock_bh(&fib_multipath_lock);
1340}
1341#endif
Linux 6.x block layer and io_uring tree(s)