net/core/fib_rules.c

   1 /*
   2  * net/core/fib_rules.c         Generic Routing Rules
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License as
   6  *      published by the Free Software Foundation, version 2.
   7  *
   8  * Authors:     Thomas Graf <tgraf@suug.ch>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/list.h>
  15 #include <net/net_namespace.h>
  16 #include <net/sock.h>
  17 #include <net/fib_rules.h>
  18
  19 int fib_default_rule_add(struct fib_rules_ops *ops,
  20                          u32 pref, u32 table, u32 flags)
  21 {
  22         struct fib_rule *r;
  23
  24         r = kzalloc(ops->rule_size, GFP_KERNEL);
  25         if (r == NULL)
  26                 return -ENOMEM;
  27
  28         atomic_set(&r->refcnt, 1);
  29         r->action = FR_ACT_TO_TBL;
  30         r->pref = pref;
  31         r->table = table;
  32         r->flags = flags;
  33         r->fr_net = hold_net(ops->fro_net);
  34
  35         /* The lock is not required here, the list in unreacheable
  36          * at the moment this function is called */
  37         list_add_tail(&r->list, &ops->rules_list);
  38         return 0;
  39 }
  40 EXPORT_SYMBOL(fib_default_rule_add);
  41
  42 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  43 {
  44         struct list_head *pos;
  45         struct fib_rule *rule;
  46
  47         if (!list_empty(&ops->rules_list)) {
  48                 pos = ops->rules_list.next;
  49                 if (pos->next != &ops->rules_list) {
  50                         rule = list_entry(pos->next, struct fib_rule, list);
  51                         if (rule->pref)
  52                                 return rule->pref - 1;
  53                 }
  54         }
  55
  56         return 0;
  57 }
  58 EXPORT_SYMBOL(fib_default_rule_pref);
  59
  60 static void notify_rule_change(int event, struct fib_rule *rule,
  61                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  62                                u32 pid);
  63
  64 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  65 {
  66         struct fib_rules_ops *ops;
  67
  68         rcu_read_lock();
  69         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  70                 if (ops->family == family) {
  71                         if (!try_module_get(ops->owner))
  72                                 ops = NULL;
  73                         rcu_read_unlock();
  74                         return ops;
  75                 }
  76         }
  77         rcu_read_unlock();
  78
  79         return NULL;
  80 }
  81
  82 static void rules_ops_put(struct fib_rules_ops *ops)
  83 {
  84         if (ops)
  85                 module_put(ops->owner);
  86 }
  87
  88 static void flush_route_cache(struct fib_rules_ops *ops)
  89 {
  90         if (ops->flush_cache)
  91                 ops->flush_cache(ops);
  92 }
  93
  94 static int __fib_rules_register(struct fib_rules_ops *ops)
  95 {
  96         int err = -EEXIST;
  97         struct fib_rules_ops *o;
  98         struct net *net;
  99
 100         net = ops->fro_net;
 101
 102         if (ops->rule_size < sizeof(struct fib_rule))
 103                 return -EINVAL;
 104
 105         if (ops->match == NULL || ops->configure == NULL ||
 106             ops->compare == NULL || ops->fill == NULL ||
 107             ops->action == NULL)
 108                 return -EINVAL;
 109
 110         spin_lock(&net->rules_mod_lock);
 111         list_for_each_entry(o, &net->rules_ops, list)
 112                 if (ops->family == o->family)
 113                         goto errout;
 114
 115         hold_net(net);
 116         list_add_tail_rcu(&ops->list, &net->rules_ops);
 117         err = 0;
 118 errout:
 119         spin_unlock(&net->rules_mod_lock);
 120
 121         return err;
 122 }
 123
 124 struct fib_rules_ops *
 125 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 126 {
 127         struct fib_rules_ops *ops;
 128         int err;
 129
 130         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 131         if (ops == NULL)
 132                 return ERR_PTR(-ENOMEM);
 133
 134         INIT_LIST_HEAD(&ops->rules_list);
 135         ops->fro_net = net;
 136
 137         err = __fib_rules_register(ops);
 138         if (err) {
 139                 kfree(ops);
 140                 ops = ERR_PTR(err);
 141         }
 142
 143         return ops;
 144 }
 145 EXPORT_SYMBOL_GPL(fib_rules_register);
 146
 147 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 148 {
 149         struct fib_rule *rule, *tmp;
 150
 151         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 152                 list_del_rcu(&rule->list);
 153                 fib_rule_put(rule);
 154         }
 155 }
 156
 157 static void fib_rules_put_rcu(struct rcu_head *head)
 158 {
 159         struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
 160         struct net *net = ops->fro_net;
 161
 162         release_net(net);
 163         kfree(ops);
 164 }
 165
 166 void fib_rules_unregister(struct fib_rules_ops *ops)
 167 {
 168         struct net *net = ops->fro_net;
 169
 170         spin_lock(&net->rules_mod_lock);
 171         list_del_rcu(&ops->list);
 172         fib_rules_cleanup_ops(ops);
 173         spin_unlock(&net->rules_mod_lock);
 174
 175         call_rcu(&ops->rcu, fib_rules_put_rcu);
 176 }
 177 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 178
 179 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 180                           struct flowi *fl, int flags)
 181 {
 182         int ret = 0;
 183
 184         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 185                 goto out;
 186
 187         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 188                 goto out;
 189
 190         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 191                 goto out;
 192
 193         ret = ops->match(rule, fl, flags);
 194 out:
 195         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 196 }
 197
 198 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 199                      int flags, struct fib_lookup_arg *arg)
 200 {
 201         struct fib_rule *rule;
 202         int err;
 203
 204         rcu_read_lock();
 205
 206         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 207 jumped:
 208                 if (!fib_rule_match(rule, ops, fl, flags))
 209                         continue;
 210
 211                 if (rule->action == FR_ACT_GOTO) {
 212                         struct fib_rule *target;
 213
 214                         target = rcu_dereference(rule->ctarget);
 215                         if (target == NULL) {
 216                                 continue;
 217                         } else {
 218                                 rule = target;
 219                                 goto jumped;
 220                         }
 221                 } else if (rule->action == FR_ACT_NOP)
 222                         continue;
 223                 else
 224                         err = ops->action(rule, fl, flags, arg);
 225
 226                 if (err != -EAGAIN) {
 227                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 228                             likely(atomic_inc_not_zero(&rule->refcnt))) {
 229                                 arg->rule = rule;
 230                                 goto out;
 231                         }
 232                         break;
 233                 }
 234         }
 235
 236         err = -ESRCH;
 237 out:
 238         rcu_read_unlock();
 239
 240         return err;
 241 }
 242 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 243
 244 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 245                             struct fib_rules_ops *ops)
 246 {
 247         int err = -EINVAL;
 248
 249         if (frh->src_len)
 250                 if (tb[FRA_SRC] == NULL ||
 251                     frh->src_len > (ops->addr_size * 8) ||
 252                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 253                         goto errout;
 254
 255         if (frh->dst_len)
 256                 if (tb[FRA_DST] == NULL ||
 257                     frh->dst_len > (ops->addr_size * 8) ||
 258                     nla_len(tb[FRA_DST]) != ops->addr_size)
 259                         goto errout;
 260
 261         err = 0;
 262 errout:
 263         return err;
 264 }
 265
 266 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 267 {
 268         struct net *net = sock_net(skb->sk);
 269         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 270         struct fib_rules_ops *ops = NULL;
 271         struct fib_rule *rule, *r, *last = NULL;
 272         struct nlattr *tb[FRA_MAX+1];
 273         int err = -EINVAL, unresolved = 0;
 274
 275         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 276                 goto errout;
 277
 278         ops = lookup_rules_ops(net, frh->family);
 279         if (ops == NULL) {
 280                 err = -EAFNOSUPPORT;
 281                 goto errout;
 282         }
 283
 284         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 285         if (err < 0)
 286                 goto errout;
 287
 288         err = validate_rulemsg(frh, tb, ops);
 289         if (err < 0)
 290                 goto errout;
 291
 292         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 293         if (rule == NULL) {
 294                 err = -ENOMEM;
 295                 goto errout;
 296         }
 297         rule->fr_net = hold_net(net);
 298
 299         if (tb[FRA_PRIORITY])
 300                 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 301
 302         if (tb[FRA_IIFNAME]) {
 303                 struct net_device *dev;
 304
 305                 rule->iifindex = -1;
 306                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 307                 dev = __dev_get_by_name(net, rule->iifname);
 308                 if (dev)
 309                         rule->iifindex = dev->ifindex;
 310         }
 311
 312         if (tb[FRA_OIFNAME]) {
 313                 struct net_device *dev;
 314
 315                 rule->oifindex = -1;
 316                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 317                 dev = __dev_get_by_name(net, rule->oifname);
 318                 if (dev)
 319                         rule->oifindex = dev->ifindex;
 320         }
 321
 322         if (tb[FRA_FWMARK]) {
 323                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 324                 if (rule->mark)
 325                         /* compatibility: if the mark value is non-zero all bits
 326                          * are compared unless a mask is explicitly specified.
 327                          */
 328                         rule->mark_mask = 0xFFFFFFFF;
 329         }
 330
 331         if (tb[FRA_FWMASK])
 332                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 333
 334         rule->action = frh->action;
 335         rule->flags = frh->flags;
 336         rule->table = frh_get_table(frh, tb);
 337
 338         if (!tb[FRA_PRIORITY] && ops->default_pref)
 339                 rule->pref = ops->default_pref(ops);
 340
 341         err = -EINVAL;
 342         if (tb[FRA_GOTO]) {
 343                 if (rule->action != FR_ACT_GOTO)
 344                         goto errout_free;
 345
 346                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 347                 /* Backward jumps are prohibited to avoid endless loops */
 348                 if (rule->target <= rule->pref)
 349                         goto errout_free;
 350
 351                 list_for_each_entry(r, &ops->rules_list, list) {
 352                         if (r->pref == rule->target) {
 353                                 RCU_INIT_POINTER(rule->ctarget, r);
 354                                 break;
 355                         }
 356                 }
 357
 358                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 359                         unresolved = 1;
 360         } else if (rule->action == FR_ACT_GOTO)
 361                 goto errout_free;
 362
 363         err = ops->configure(rule, skb, frh, tb);
 364         if (err < 0)
 365                 goto errout_free;
 366
 367         list_for_each_entry(r, &ops->rules_list, list) {
 368                 if (r->pref > rule->pref)
 369                         break;
 370                 last = r;
 371         }
 372
 373         fib_rule_get(rule);
 374
 375         if (last)
 376                 list_add_rcu(&rule->list, &last->list);
 377         else
 378                 list_add_rcu(&rule->list, &ops->rules_list);
 379
 380         if (ops->unresolved_rules) {
 381                 /*
 382                  * There are unresolved goto rules in the list, check if
 383                  * any of them are pointing to this new rule.
 384                  */
 385                 list_for_each_entry(r, &ops->rules_list, list) {
 386                         if (r->action == FR_ACT_GOTO &&
 387                             r->target == rule->pref &&
 388                             rtnl_dereference(r->ctarget) == NULL) {
 389                                 rcu_assign_pointer(r->ctarget, rule);
 390                                 if (--ops->unresolved_rules == 0)
 391                                         break;
 392                         }
 393                 }
 394         }
 395
 396         if (rule->action == FR_ACT_GOTO)
 397                 ops->nr_goto_rules++;
 398
 399         if (unresolved)
 400                 ops->unresolved_rules++;
 401
 402         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
 403         flush_route_cache(ops);
 404         rules_ops_put(ops);
 405         return 0;
 406
 407 errout_free:
 408         release_net(rule->fr_net);
 409         kfree(rule);
 410 errout:
 411         rules_ops_put(ops);
 412         return err;
 413 }
 414
 415 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 416 {
 417         struct net *net = sock_net(skb->sk);
 418         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 419         struct fib_rules_ops *ops = NULL;
 420         struct fib_rule *rule, *tmp;
 421         struct nlattr *tb[FRA_MAX+1];
 422         int err = -EINVAL;
 423
 424         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 425                 goto errout;
 426
 427         ops = lookup_rules_ops(net, frh->family);
 428         if (ops == NULL) {
 429                 err = -EAFNOSUPPORT;
 430                 goto errout;
 431         }
 432
 433         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 434         if (err < 0)
 435                 goto errout;
 436
 437         err = validate_rulemsg(frh, tb, ops);
 438         if (err < 0)
 439                 goto errout;
 440
 441         list_for_each_entry(rule, &ops->rules_list, list) {
 442                 if (frh->action && (frh->action != rule->action))
 443                         continue;
 444
 445                 if (frh->table && (frh_get_table(frh, tb) != rule->table))
 446                         continue;
 447
 448                 if (tb[FRA_PRIORITY] &&
 449                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 450                         continue;
 451
 452                 if (tb[FRA_IIFNAME] &&
 453                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 454                         continue;
 455
 456                 if (tb[FRA_OIFNAME] &&
 457                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 458                         continue;
 459
 460                 if (tb[FRA_FWMARK] &&
 461                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 462                         continue;
 463
 464                 if (tb[FRA_FWMASK] &&
 465                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 466                         continue;
 467
 468                 if (!ops->compare(rule, frh, tb))
 469                         continue;
 470
 471                 if (rule->flags & FIB_RULE_PERMANENT) {
 472                         err = -EPERM;
 473                         goto errout;
 474                 }
 475
 476                 list_del_rcu(&rule->list);
 477
 478                 if (rule->action == FR_ACT_GOTO)
 479                         ops->nr_goto_rules--;
 480
 481                 /*
 482                  * Check if this rule is a target to any of them. If so,
 483                  * disable them. As this operation is eventually very
 484                  * expensive, it is only performed if goto rules have
 485                  * actually been added.
 486                  */
 487                 if (ops->nr_goto_rules > 0) {
 488                         list_for_each_entry(tmp, &ops->rules_list, list) {
 489                                 if (rtnl_dereference(tmp->ctarget) == rule) {
 490                                         rcu_assign_pointer(tmp->ctarget, NULL);
 491                                         ops->unresolved_rules++;
 492                                 }
 493                         }
 494                 }
 495
 496                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 497                                    NETLINK_CB(skb).pid);
 498                 fib_rule_put(rule);
 499                 flush_route_cache(ops);
 500                 rules_ops_put(ops);
 501                 return 0;
 502         }
 503
 504         err = -ENOENT;
 505 errout:
 506         rules_ops_put(ops);
 507         return err;
 508 }
 509
 510 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 511                                          struct fib_rule *rule)
 512 {
 513         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 514                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 515                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 516                          + nla_total_size(4) /* FRA_PRIORITY */
 517                          + nla_total_size(4) /* FRA_TABLE */
 518                          + nla_total_size(4) /* FRA_FWMARK */
 519                          + nla_total_size(4); /* FRA_FWMASK */
 520
 521         if (ops->nlmsg_payload)
 522                 payload += ops->nlmsg_payload(rule);
 523
 524         return payload;
 525 }
 526
 527 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 528                             u32 pid, u32 seq, int type, int flags,
 529                             struct fib_rules_ops *ops)
 530 {
 531         struct nlmsghdr *nlh;
 532         struct fib_rule_hdr *frh;
 533
 534         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 535         if (nlh == NULL)
 536                 return -EMSGSIZE;
 537
 538         frh = nlmsg_data(nlh);
 539         frh->family = ops->family;
 540         frh->table = rule->table;
 541         NLA_PUT_U32(skb, FRA_TABLE, rule->table);
 542         frh->res1 = 0;
 543         frh->res2 = 0;
 544         frh->action = rule->action;
 545         frh->flags = rule->flags;
 546
 547         if (rule->action == FR_ACT_GOTO &&
 548             rcu_dereference_raw(rule->ctarget) == NULL)
 549                 frh->flags |= FIB_RULE_UNRESOLVED;
 550
 551         if (rule->iifname[0]) {
 552                 NLA_PUT_STRING(skb, FRA_IIFNAME, rule->iifname);
 553
 554                 if (rule->iifindex == -1)
 555                         frh->flags |= FIB_RULE_IIF_DETACHED;
 556         }
 557
 558         if (rule->oifname[0]) {
 559                 NLA_PUT_STRING(skb, FRA_OIFNAME, rule->oifname);
 560
 561                 if (rule->oifindex == -1)
 562                         frh->flags |= FIB_RULE_OIF_DETACHED;
 563         }
 564
 565         if (rule->pref)
 566                 NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
 567
 568         if (rule->mark)
 569                 NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);
 570
 571         if (rule->mark_mask || rule->mark)
 572                 NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);
 573
 574         if (rule->target)
 575                 NLA_PUT_U32(skb, FRA_GOTO, rule->target);
 576
 577         if (ops->fill(rule, skb, frh) < 0)
 578                 goto nla_put_failure;
 579
 580         return nlmsg_end(skb, nlh);
 581
 582 nla_put_failure:
 583         nlmsg_cancel(skb, nlh);
 584         return -EMSGSIZE;
 585 }
 586
 587 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 588                       struct fib_rules_ops *ops)
 589 {
 590         int idx = 0;
 591         struct fib_rule *rule;
 592
 593         rcu_read_lock();
 594         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 595                 if (idx < cb->args[1])
 596                         goto skip;
 597
 598                 if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
 599                                      cb->nlh->nlmsg_seq, RTM_NEWRULE,
 600                                      NLM_F_MULTI, ops) < 0)
 601                         break;
 602 skip:
 603                 idx++;
 604         }
 605         rcu_read_unlock();
 606         cb->args[1] = idx;
 607         rules_ops_put(ops);
 608
 609         return skb->len;
 610 }
 611
 612 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 613 {
 614         struct net *net = sock_net(skb->sk);
 615         struct fib_rules_ops *ops;
 616         int idx = 0, family;
 617
 618         family = rtnl_msg_family(cb->nlh);
 619         if (family != AF_UNSPEC) {
 620                 /* Protocol specific dump request */
 621                 ops = lookup_rules_ops(net, family);
 622                 if (ops == NULL)
 623                         return -EAFNOSUPPORT;
 624
 625                 return dump_rules(skb, cb, ops);
 626         }
 627
 628         rcu_read_lock();
 629         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 630                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 631                         goto skip;
 632
 633                 if (dump_rules(skb, cb, ops) < 0)
 634                         break;
 635
 636                 cb->args[1] = 0;
 637 skip:
 638                 idx++;
 639         }
 640         rcu_read_unlock();
 641         cb->args[0] = idx;
 642
 643         return skb->len;
 644 }
 645
 646 static void notify_rule_change(int event, struct fib_rule *rule,
 647                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 648                                u32 pid)
 649 {
 650         struct net *net;
 651         struct sk_buff *skb;
 652         int err = -ENOBUFS;
 653
 654         net = ops->fro_net;
 655         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 656         if (skb == NULL)
 657                 goto errout;
 658
 659         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 660         if (err < 0) {
 661                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 662                 WARN_ON(err == -EMSGSIZE);
 663                 kfree_skb(skb);
 664                 goto errout;
 665         }
 666
 667         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 668         return;
 669 errout:
 670         if (err < 0)
 671                 rtnl_set_sk_err(net, ops->nlgroup, err);
 672 }
 673
 674 static void attach_rules(struct list_head *rules, struct net_device *dev)
 675 {
 676         struct fib_rule *rule;
 677
 678         list_for_each_entry(rule, rules, list) {
 679                 if (rule->iifindex == -1 &&
 680                     strcmp(dev->name, rule->iifname) == 0)
 681                         rule->iifindex = dev->ifindex;
 682                 if (rule->oifindex == -1 &&
 683                     strcmp(dev->name, rule->oifname) == 0)
 684                         rule->oifindex = dev->ifindex;
 685         }
 686 }
 687
 688 static void detach_rules(struct list_head *rules, struct net_device *dev)
 689 {
 690         struct fib_rule *rule;
 691
 692         list_for_each_entry(rule, rules, list) {
 693                 if (rule->iifindex == dev->ifindex)
 694                         rule->iifindex = -1;
 695                 if (rule->oifindex == dev->ifindex)
 696                         rule->oifindex = -1;
 697         }
 698 }
 699
 700
 701 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 702                             void *ptr)
 703 {
 704         struct net_device *dev = ptr;
 705         struct net *net = dev_net(dev);
 706         struct fib_rules_ops *ops;
 707
 708         ASSERT_RTNL();
 709
 710         switch (event) {
 711         case NETDEV_REGISTER:
 712                 list_for_each_entry(ops, &net->rules_ops, list)
 713                         attach_rules(&ops->rules_list, dev);
 714                 break;
 715
 716         case NETDEV_UNREGISTER:
 717                 list_for_each_entry(ops, &net->rules_ops, list)
 718                         detach_rules(&ops->rules_list, dev);
 719                 break;
 720         }
 721
 722         return NOTIFY_DONE;
 723 }
 724
 725 static struct notifier_block fib_rules_notifier = {
 726         .notifier_call = fib_rules_event,
 727 };
 728
 729 static int __net_init fib_rules_net_init(struct net *net)
 730 {
 731         INIT_LIST_HEAD(&net->rules_ops);
 732         spin_lock_init(&net->rules_mod_lock);
 733         return 0;
 734 }
 735
 736 static struct pernet_operations fib_rules_net_ops = {
 737         .init = fib_rules_net_init,
 738 };
 739
 740 static int __init fib_rules_init(void)
 741 {
 742         int err;
 743         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL);
 744         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL);
 745         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule);
 746
 747         err = register_pernet_subsys(&fib_rules_net_ops);
 748         if (err < 0)
 749                 goto fail;
 750
 751         err = register_netdevice_notifier(&fib_rules_notifier);
 752         if (err < 0)
 753                 goto fail_unregister;
 754
 755         return 0;
 756
 757 fail_unregister:
 758         unregister_pernet_subsys(&fib_rules_net_ops);
 759 fail:
 760         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 761         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 762         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 763         return err;
 764 }
 765
 766 subsys_initcall(fib_rules_init);