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 <[email protected]>
   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->iif) &&
 185             !(fl->flags & FLOWI_FLAG_MATCH_ANY_IIF))
 186                 goto out;
 187
 188         if (rule->oifindex && (rule->oifindex != fl->oif))
 189                 goto out;
 190
 191         if ((rule->mark ^ fl->mark) & rule->mark_mask)
 192                 goto out;
 193
 194         ret = ops->match(rule, fl, flags);
 195 out:
 196         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 197 }
 198
 199 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 200                      int flags, struct fib_lookup_arg *arg)
 201 {
 202         struct fib_rule *rule;
 203         int err;
 204
 205         rcu_read_lock();
 206
 207         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 208 jumped:
 209                 if (!fib_rule_match(rule, ops, fl, flags))
 210                         continue;
 211
 212                 if (rule->action == FR_ACT_GOTO) {
 213                         struct fib_rule *target;
 214
 215                         target = rcu_dereference(rule->ctarget);
 216                         if (target == NULL) {
 217                                 continue;
 218                         } else {
 219                                 rule = target;
 220                                 goto jumped;
 221                         }
 222                 } else if (rule->action == FR_ACT_NOP)
 223                         continue;
 224                 else
 225                         err = ops->action(rule, fl, flags, arg);
 226
 227                 if (err != -EAGAIN) {
 228                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 229                             likely(atomic_inc_not_zero(&rule->refcnt))) {
 230                                 arg->rule = rule;
 231                                 goto out;
 232                         }
 233                         break;
 234                 }
 235         }
 236
 237         err = -ESRCH;
 238 out:
 239         rcu_read_unlock();
 240
 241         return err;
 242 }
 243 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 244
 245 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 246                             struct fib_rules_ops *ops)
 247 {
 248         int err = -EINVAL;
 249
 250         if (frh->src_len)
 251                 if (tb[FRA_SRC] == NULL ||
 252                     frh->src_len > (ops->addr_size * 8) ||
 253                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 254                         goto errout;
 255
 256         if (frh->dst_len)
 257                 if (tb[FRA_DST] == NULL ||
 258                     frh->dst_len > (ops->addr_size * 8) ||
 259                     nla_len(tb[FRA_DST]) != ops->addr_size)
 260                         goto errout;
 261
 262         err = 0;
 263 errout:
 264         return err;
 265 }
 266
 267 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 268 {
 269         struct net *net = sock_net(skb->sk);
 270         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 271         struct fib_rules_ops *ops = NULL;
 272         struct fib_rule *rule, *r, *last = NULL;
 273         struct nlattr *tb[FRA_MAX+1];
 274         int err = -EINVAL, unresolved = 0;
 275
 276         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 277                 goto errout;
 278
 279         ops = lookup_rules_ops(net, frh->family);
 280         if (ops == NULL) {
 281                 err = -EAFNOSUPPORT;
 282                 goto errout;
 283         }
 284
 285         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 286         if (err < 0)
 287                 goto errout;
 288
 289         err = validate_rulemsg(frh, tb, ops);
 290         if (err < 0)
 291                 goto errout;
 292
 293         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 294         if (rule == NULL) {
 295                 err = -ENOMEM;
 296                 goto errout;
 297         }
 298         rule->fr_net = hold_net(net);
 299
 300         if (tb[FRA_PRIORITY])
 301                 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 302
 303         if (tb[FRA_IIFNAME]) {
 304                 struct net_device *dev;
 305
 306                 rule->iifindex = -1;
 307                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 308                 dev = __dev_get_by_name(net, rule->iifname);
 309                 if (dev)
 310                         rule->iifindex = dev->ifindex;
 311         }
 312
 313         if (tb[FRA_OIFNAME]) {
 314                 struct net_device *dev;
 315
 316                 rule->oifindex = -1;
 317                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 318                 dev = __dev_get_by_name(net, rule->oifname);
 319                 if (dev)
 320                         rule->oifindex = dev->ifindex;
 321         }
 322
 323         if (tb[FRA_FWMARK]) {
 324                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 325                 if (rule->mark)
 326                         /* compatibility: if the mark value is non-zero all bits
 327                          * are compared unless a mask is explicitly specified.
 328                          */
 329                         rule->mark_mask = 0xFFFFFFFF;
 330         }
 331
 332         if (tb[FRA_FWMASK])
 333                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 334
 335         rule->action = frh->action;
 336         rule->flags = frh->flags;
 337         rule->table = frh_get_table(frh, tb);
 338
 339         if (!tb[FRA_PRIORITY] && ops->default_pref)
 340                 rule->pref = ops->default_pref(ops);
 341
 342         err = -EINVAL;
 343         if (tb[FRA_GOTO]) {
 344                 if (rule->action != FR_ACT_GOTO)
 345                         goto errout_free;
 346
 347                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 348                 /* Backward jumps are prohibited to avoid endless loops */
 349                 if (rule->target <= rule->pref)
 350                         goto errout_free;
 351
 352                 list_for_each_entry(r, &ops->rules_list, list) {
 353                         if (r->pref == rule->target) {
 354                                 RCU_INIT_POINTER(rule->ctarget, r);
 355                                 break;
 356                         }
 357                 }
 358
 359                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 360                         unresolved = 1;
 361         } else if (rule->action == FR_ACT_GOTO)
 362                 goto errout_free;
 363
 364         err = ops->configure(rule, skb, frh, tb);
 365         if (err < 0)
 366                 goto errout_free;
 367
 368         list_for_each_entry(r, &ops->rules_list, list) {
 369                 if (r->pref > rule->pref)
 370                         break;
 371                 last = r;
 372         }
 373
 374         fib_rule_get(rule);
 375
 376         if (last)
 377                 list_add_rcu(&rule->list, &last->list);
 378         else
 379                 list_add_rcu(&rule->list, &ops->rules_list);
 380
 381         if (ops->unresolved_rules) {
 382                 /*
 383                  * There are unresolved goto rules in the list, check if
 384                  * any of them are pointing to this new rule.
 385                  */
 386                 list_for_each_entry(r, &ops->rules_list, list) {
 387                         if (r->action == FR_ACT_GOTO &&
 388                             r->target == rule->pref) {
 389                                 BUG_ON(rtnl_dereference(r->ctarget) != NULL);
 390                                 rcu_assign_pointer(r->ctarget, rule);
 391                                 if (--ops->unresolved_rules == 0)
 392                                         break;
 393                         }
 394                 }
 395         }
 396
 397         if (rule->action == FR_ACT_GOTO)
 398                 ops->nr_goto_rules++;
 399
 400         if (unresolved)
 401                 ops->unresolved_rules++;
 402
 403         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
 404         flush_route_cache(ops);
 405         rules_ops_put(ops);
 406         return 0;
 407
 408 errout_free:
 409         release_net(rule->fr_net);
 410         kfree(rule);
 411 errout:
 412         rules_ops_put(ops);
 413         return err;
 414 }
 415
 416 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 417 {
 418         struct net *net = sock_net(skb->sk);
 419         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 420         struct fib_rules_ops *ops = NULL;
 421         struct fib_rule *rule, *tmp;
 422         struct nlattr *tb[FRA_MAX+1];
 423         int err = -EINVAL;
 424
 425         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 426                 goto errout;
 427
 428         ops = lookup_rules_ops(net, frh->family);
 429         if (ops == NULL) {
 430                 err = -EAFNOSUPPORT;
 431                 goto errout;
 432         }
 433
 434         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 435         if (err < 0)
 436                 goto errout;
 437
 438         err = validate_rulemsg(frh, tb, ops);
 439         if (err < 0)
 440                 goto errout;
 441
 442         list_for_each_entry(rule, &ops->rules_list, list) {
 443                 if (frh->action && (frh->action != rule->action))
 444                         continue;
 445
 446                 if (frh->table && (frh_get_table(frh, tb) != rule->table))
 447                         continue;
 448
 449                 if (tb[FRA_PRIORITY] &&
 450                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 451                         continue;
 452
 453                 if (tb[FRA_IIFNAME] &&
 454                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 455                         continue;
 456
 457                 if (tb[FRA_OIFNAME] &&
 458                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 459                         continue;
 460
 461                 if (tb[FRA_FWMARK] &&
 462                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 463                         continue;
 464
 465                 if (tb[FRA_FWMASK] &&
 466                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 467                         continue;
 468
 469                 if (!ops->compare(rule, frh, tb))
 470                         continue;
 471
 472                 if (rule->flags & FIB_RULE_PERMANENT) {
 473                         err = -EPERM;
 474                         goto errout;
 475                 }
 476
 477                 list_del_rcu(&rule->list);
 478
 479                 if (rule->action == FR_ACT_GOTO)
 480                         ops->nr_goto_rules--;
 481
 482                 /*
 483                  * Check if this rule is a target to any of them. If so,
 484                  * disable them. As this operation is eventually very
 485                  * expensive, it is only performed if goto rules have
 486                  * actually been added.
 487                  */
 488                 if (ops->nr_goto_rules > 0) {
 489                         list_for_each_entry(tmp, &ops->rules_list, list) {
 490                                 if (rtnl_dereference(tmp->ctarget) == rule) {
 491                                         rcu_assign_pointer(tmp->ctarget, NULL);
 492                                         ops->unresolved_rules++;
 493                                 }
 494                         }
 495                 }
 496
 497                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 498                                    NETLINK_CB(skb).pid);
 499                 fib_rule_put(rule);
 500                 flush_route_cache(ops);
 501                 rules_ops_put(ops);
 502                 return 0;
 503         }
 504
 505         err = -ENOENT;
 506 errout:
 507         rules_ops_put(ops);
 508         return err;
 509 }
 510
 511 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 512                                          struct fib_rule *rule)
 513 {
 514         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 515                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 516                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 517                          + nla_total_size(4) /* FRA_PRIORITY */
 518                          + nla_total_size(4) /* FRA_TABLE */
 519                          + nla_total_size(4) /* FRA_FWMARK */
 520                          + nla_total_size(4); /* FRA_FWMASK */
 521
 522         if (ops->nlmsg_payload)
 523                 payload += ops->nlmsg_payload(rule);
 524
 525         return payload;
 526 }
 527
 528 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 529                             u32 pid, u32 seq, int type, int flags,
 530                             struct fib_rules_ops *ops)
 531 {
 532         struct nlmsghdr *nlh;
 533         struct fib_rule_hdr *frh;
 534
 535         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 536         if (nlh == NULL)
 537                 return -EMSGSIZE;
 538
 539         frh = nlmsg_data(nlh);
 540         frh->family = ops->family;
 541         frh->table = rule->table;
 542         NLA_PUT_U32(skb, FRA_TABLE, rule->table);
 543         frh->res1 = 0;
 544         frh->res2 = 0;
 545         frh->action = rule->action;
 546         frh->flags = rule->flags;
 547
 548         if (rule->action == FR_ACT_GOTO &&
 549             rcu_dereference_raw(rule->ctarget) == NULL)
 550                 frh->flags |= FIB_RULE_UNRESOLVED;
 551
 552         if (rule->iifname[0]) {
 553                 NLA_PUT_STRING(skb, FRA_IIFNAME, rule->iifname);
 554
 555                 if (rule->iifindex == -1)
 556                         frh->flags |= FIB_RULE_IIF_DETACHED;
 557         }
 558
 559         if (rule->oifname[0]) {
 560                 NLA_PUT_STRING(skb, FRA_OIFNAME, rule->oifname);
 561
 562                 if (rule->oifindex == -1)
 563                         frh->flags |= FIB_RULE_OIF_DETACHED;
 564         }
 565
 566         if (rule->pref)
 567                 NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
 568
 569         if (rule->mark)
 570                 NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);
 571
 572         if (rule->mark_mask || rule->mark)
 573                 NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);
 574
 575         if (rule->target)
 576                 NLA_PUT_U32(skb, FRA_GOTO, rule->target);
 577
 578         if (ops->fill(rule, skb, frh) < 0)
 579                 goto nla_put_failure;
 580
 581         return nlmsg_end(skb, nlh);
 582
 583 nla_put_failure:
 584         nlmsg_cancel(skb, nlh);
 585         return -EMSGSIZE;
 586 }
 587
 588 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 589                       struct fib_rules_ops *ops)
 590 {
 591         int idx = 0;
 592         struct fib_rule *rule;
 593
 594         list_for_each_entry(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         cb->args[1] = idx;
 606         rules_ops_put(ops);
 607
 608         return skb->len;
 609 }
 610
 611 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 612 {
 613         struct net *net = sock_net(skb->sk);
 614         struct fib_rules_ops *ops;
 615         int idx = 0, family;
 616
 617         family = rtnl_msg_family(cb->nlh);
 618         if (family != AF_UNSPEC) {
 619                 /* Protocol specific dump request */
 620                 ops = lookup_rules_ops(net, family);
 621                 if (ops == NULL)
 622                         return -EAFNOSUPPORT;
 623
 624                 return dump_rules(skb, cb, ops);
 625         }
 626
 627         rcu_read_lock();
 628         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 629                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 630                         goto skip;
 631
 632                 if (dump_rules(skb, cb, ops) < 0)
 633                         break;
 634
 635                 cb->args[1] = 0;
 636 skip:
 637                 idx++;
 638         }
 639         rcu_read_unlock();
 640         cb->args[0] = idx;
 641
 642         return skb->len;
 643 }
 644
 645 static void notify_rule_change(int event, struct fib_rule *rule,
 646                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 647                                u32 pid)
 648 {
 649         struct net *net;
 650         struct sk_buff *skb;
 651         int err = -ENOBUFS;
 652
 653         net = ops->fro_net;
 654         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 655         if (skb == NULL)
 656                 goto errout;
 657
 658         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 659         if (err < 0) {
 660                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 661                 WARN_ON(err == -EMSGSIZE);
 662                 kfree_skb(skb);
 663                 goto errout;
 664         }
 665
 666         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 667         return;
 668 errout:
 669         if (err < 0)
 670                 rtnl_set_sk_err(net, ops->nlgroup, err);
 671 }
 672
 673 static void attach_rules(struct list_head *rules, struct net_device *dev)
 674 {
 675         struct fib_rule *rule;
 676
 677         list_for_each_entry(rule, rules, list) {
 678                 if (rule->iifindex == -1 &&
 679                     strcmp(dev->name, rule->iifname) == 0)
 680                         rule->iifindex = dev->ifindex;
 681                 if (rule->oifindex == -1 &&
 682                     strcmp(dev->name, rule->oifname) == 0)
 683                         rule->oifindex = dev->ifindex;
 684         }
 685 }
 686
 687 static void detach_rules(struct list_head *rules, struct net_device *dev)
 688 {
 689         struct fib_rule *rule;
 690
 691         list_for_each_entry(rule, rules, list) {
 692                 if (rule->iifindex == dev->ifindex)
 693                         rule->iifindex = -1;
 694                 if (rule->oifindex == dev->ifindex)
 695                         rule->oifindex = -1;
 696         }
 697 }
 698
 699
 700 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 701                             void *ptr)
 702 {
 703         struct net_device *dev = ptr;
 704         struct net *net = dev_net(dev);
 705         struct fib_rules_ops *ops;
 706
 707         ASSERT_RTNL();
 708
 709         switch (event) {
 710         case NETDEV_REGISTER:
 711                 list_for_each_entry(ops, &net->rules_ops, list)
 712                         attach_rules(&ops->rules_list, dev);
 713                 break;
 714
 715         case NETDEV_UNREGISTER:
 716                 list_for_each_entry(ops, &net->rules_ops, list)
 717                         detach_rules(&ops->rules_list, dev);
 718                 break;
 719         }
 720
 721         return NOTIFY_DONE;
 722 }
 723
 724 static struct notifier_block fib_rules_notifier = {
 725         .notifier_call = fib_rules_event,
 726 };
 727
 728 static int __net_init fib_rules_net_init(struct net *net)
 729 {
 730         INIT_LIST_HEAD(&net->rules_ops);
 731         spin_lock_init(&net->rules_mod_lock);
 732         return 0;
 733 }
 734
 735 static struct pernet_operations fib_rules_net_ops = {
 736         .init = fib_rules_net_init,
 737 };
 738
 739 static int __init fib_rules_init(void)
 740 {
 741         int err;
 742         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL);
 743         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL);
 744         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule);
 745
 746         err = register_pernet_subsys(&fib_rules_net_ops);
 747         if (err < 0)
 748                 goto fail;
 749
 750         err = register_netdevice_notifier(&fib_rules_notifier);
 751         if (err < 0)
 752                 goto fail_unregister;
 753
 754         return 0;
 755
 756 fail_unregister:
 757         unregister_pernet_subsys(&fib_rules_net_ops);
 758 fail:
 759         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 760         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 761         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 762         return err;
 763 }
 764
 765 subsys_initcall(fib_rules_init);