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 <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>
  31 #include <linux/inetdevice.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/arp.h>
  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
  52 static DEFINE_RWLOCK(fib_info_lock);
  53 static struct hlist_head *fib_info_hash;
  54 static struct hlist_head *fib_info_laddrhash;
  55 static unsigned int fib_hash_size;
  56 static unsigned int fib_info_cnt;
  57
  58 #define DEVINDEX_HASHBITS 8
  59 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
  60 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
  61
  62 #ifdef CONFIG_IP_ROUTE_MULTIPATH
  63
  64 static DEFINE_SPINLOCK(fib_multipath_lock);
  65
  66 #define for_nexthops(fi) { int nhsel; const struct fib_nh * nh; \
  67 for (nhsel=0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
  68
  69 #define change_nexthops(fi) { int nhsel; struct fib_nh * nh; \
  70 for (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; \
  77 for (nhsel=0; nhsel < 1; nhsel++)
  78
  79 #define change_nexthops(fi) { int nhsel=0; struct fib_nh * nh = (struct fib_nh*)((fi)->fib_nh); \
  80 for (nhsel=0; nhsel < 1; nhsel++)
  81
  82 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
  83
  84 #define endfor_nexthops(fi) }
  85
  86
  87 static const struct
  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
 145 void 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
 160 void 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
 178 static __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
 199 static 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
 211 static 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
 237 static 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
 250 int 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
 275 void 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;
 280         u32 pid = req ? req->pid : n->nlmsg_pid;
 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,
 290                           fa->fa_info, 0) < 0) {
 291                 kfree_skb(skb);
 292                 return;
 293         }
 294         NETLINK_CB(skb).dst_group = RTNLGRP_IPV4_ROUTE;
 295         if (n->nlmsg_flags&NLM_F_ECHO)
 296                 atomic_inc(&skb->users);
 297         netlink_broadcast(rtnl, skb, pid, RTNLGRP_IPV4_ROUTE, GFP_KERNEL);
 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  */
 305 struct 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
 320 int 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
 345 static 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
 355 static int
 356 fib_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
 371 static int
 372 fib_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
 397 int 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
 491 static 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;
 542 out:
 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
 566 static 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
 573 static 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
 582 static 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
 593 static void fib_hash_move(struct hlist_head *new_info_hash,
 594                           struct hlist_head *new_laddrhash,
 595                           unsigned int new_size)
 596 {
 597         struct hlist_head *old_info_hash, *old_laddrhash;
 598         unsigned int old_size = fib_hash_size;
 599         unsigned int i, bytes;
 600
 601         write_lock(&fib_info_lock);
 602         old_info_hash = fib_info_hash;
 603         old_laddrhash = fib_info_laddrhash;
 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);
 643
 644         bytes = old_size * sizeof(struct hlist_head *);
 645         fib_hash_free(old_info_hash, bytes);
 646         fib_hash_free(old_laddrhash, bytes);
 647 }
 648
 649 struct fib_info *
 650 fib_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 = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
 713         if (fi == NULL)
 714                 goto failure;
 715         fib_info_cnt++;
 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 = 0;
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