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