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 <linux/module.h>
  16 #include <net/net_namespace.h>
  17 #include <net/sock.h>
  18 #include <net/fib_rules.h>
  19
  20 int fib_default_rule_add(struct fib_rules_ops *ops,
  21                          u32 pref, u32 table, u32 flags)
  22 {
  23         struct fib_rule *r;
  24
  25         r = kzalloc(ops->rule_size, GFP_KERNEL);
  26         if (r == NULL)
  27                 return -ENOMEM;
  28
  29         atomic_set(&r->refcnt, 1);
  30         r->action = FR_ACT_TO_TBL;
  31         r->pref = pref;
  32         r->table = table;
  33         r->flags = flags;
  34         r->fr_net = hold_net(ops->fro_net);
  35
  36         r->suppress_prefixlen = -1;
  37         r->suppress_ifgroup = -1;
  38
  39         /* The lock is not required here, the list in unreacheable
  40          * at the moment this function is called */
  41         list_add_tail(&r->list, &ops->rules_list);
  42         return 0;
  43 }
  44 EXPORT_SYMBOL(fib_default_rule_add);
  45
  46 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  47 {
  48         struct list_head *pos;
  49         struct fib_rule *rule;
  50
  51         if (!list_empty(&ops->rules_list)) {
  52                 pos = ops->rules_list.next;
  53                 if (pos->next != &ops->rules_list) {
  54                         rule = list_entry(pos->next, struct fib_rule, list);
  55                         if (rule->pref)
  56                                 return rule->pref - 1;
  57                 }
  58         }
  59
  60         return 0;
  61 }
  62 EXPORT_SYMBOL(fib_default_rule_pref);
  63
  64 static void notify_rule_change(int event, struct fib_rule *rule,
  65                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  66                                u32 pid);
  67
  68 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  69 {
  70         struct fib_rules_ops *ops;
  71
  72         rcu_read_lock();
  73         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  74                 if (ops->family == family) {
  75                         if (!try_module_get(ops->owner))
  76                                 ops = NULL;
  77                         rcu_read_unlock();
  78                         return ops;
  79                 }
  80         }
  81         rcu_read_unlock();
  82
  83         return NULL;
  84 }
  85
  86 static void rules_ops_put(struct fib_rules_ops *ops)
  87 {
  88         if (ops)
  89                 module_put(ops->owner);
  90 }
  91
  92 static void flush_route_cache(struct fib_rules_ops *ops)
  93 {
  94         if (ops->flush_cache)
  95                 ops->flush_cache(ops);
  96 }
  97
  98 static int __fib_rules_register(struct fib_rules_ops *ops)
  99 {
 100         int err = -EEXIST;
 101         struct fib_rules_ops *o;
 102         struct net *net;
 103
 104         net = ops->fro_net;
 105
 106         if (ops->rule_size < sizeof(struct fib_rule))
 107                 return -EINVAL;
 108
 109         if (ops->match == NULL || ops->configure == NULL ||
 110             ops->compare == NULL || ops->fill == NULL ||
 111             ops->action == NULL)
 112                 return -EINVAL;
 113
 114         spin_lock(&net->rules_mod_lock);
 115         list_for_each_entry(o, &net->rules_ops, list)
 116                 if (ops->family == o->family)
 117                         goto errout;
 118
 119         hold_net(net);
 120         list_add_tail_rcu(&ops->list, &net->rules_ops);
 121         err = 0;
 122 errout:
 123         spin_unlock(&net->rules_mod_lock);
 124
 125         return err;
 126 }
 127
 128 struct fib_rules_ops *
 129 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 130 {
 131         struct fib_rules_ops *ops;
 132         int err;
 133
 134         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 135         if (ops == NULL)
 136                 return ERR_PTR(-ENOMEM);
 137
 138         INIT_LIST_HEAD(&ops->rules_list);
 139         ops->fro_net = net;
 140
 141         err = __fib_rules_register(ops);
 142         if (err) {
 143                 kfree(ops);
 144                 ops = ERR_PTR(err);
 145         }
 146
 147         return ops;
 148 }
 149 EXPORT_SYMBOL_GPL(fib_rules_register);
 150
 151 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 152 {
 153         struct fib_rule *rule, *tmp;
 154
 155         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 156                 list_del_rcu(&rule->list);
 157                 if (ops->delete)
 158                         ops->delete(rule);
 159                 fib_rule_put(rule);
 160         }
 161 }
 162
 163 static void fib_rules_put_rcu(struct rcu_head *head)
 164 {
 165         struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
 166         struct net *net = ops->fro_net;
 167
 168         release_net(net);
 169         kfree(ops);
 170 }
 171
 172 void fib_rules_unregister(struct fib_rules_ops *ops)
 173 {
 174         struct net *net = ops->fro_net;
 175
 176         spin_lock(&net->rules_mod_lock);
 177         list_del_rcu(&ops->list);
 178         fib_rules_cleanup_ops(ops);
 179         spin_unlock(&net->rules_mod_lock);
 180
 181         call_rcu(&ops->rcu, fib_rules_put_rcu);
 182 }
 183 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 184
 185 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 186                           struct flowi *fl, int flags)
 187 {
 188         int ret = 0;
 189
 190         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 191                 goto out;
 192
 193         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 194                 goto out;
 195
 196         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 197                 goto out;
 198
 199         ret = ops->match(rule, fl, flags);
 200 out:
 201         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 202 }
 203
 204 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 205                      int flags, struct fib_lookup_arg *arg)
 206 {
 207         struct fib_rule *rule;
 208         int err;
 209
 210         rcu_read_lock();
 211
 212         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 213 jumped:
 214                 if (!fib_rule_match(rule, ops, fl, flags))
 215                         continue;
 216
 217                 if (rule->action == FR_ACT_GOTO) {
 218                         struct fib_rule *target;
 219
 220                         target = rcu_dereference(rule->ctarget);
 221                         if (target == NULL) {
 222                                 continue;
 223                         } else {
 224                                 rule = target;
 225                                 goto jumped;
 226                         }
 227                 } else if (rule->action == FR_ACT_NOP)
 228                         continue;
 229                 else
 230                         err = ops->action(rule, fl, flags, arg);
 231
 232                 if (!err && ops->suppress && ops->suppress(rule, arg))
 233                         continue;
 234
 235                 if (err != -EAGAIN) {
 236                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 237                             likely(atomic_inc_not_zero(&rule->refcnt))) {
 238                                 arg->rule = rule;
 239                                 goto out;
 240                         }
 241                         break;
 242                 }
 243         }
 244
 245         err = -ESRCH;
 246 out:
 247         rcu_read_unlock();
 248
 249         return err;
 250 }
 251 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 252
 253 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 254                             struct fib_rules_ops *ops)
 255 {
 256         int err = -EINVAL;
 257
 258         if (frh->src_len)
 259                 if (tb[FRA_SRC] == NULL ||
 260                     frh->src_len > (ops->addr_size * 8) ||
 261                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 262                         goto errout;
 263
 264         if (frh->dst_len)
 265                 if (tb[FRA_DST] == NULL ||
 266                     frh->dst_len > (ops->addr_size * 8) ||
 267                     nla_len(tb[FRA_DST]) != ops->addr_size)
 268                         goto errout;
 269
 270         err = 0;
 271 errout:
 272         return err;
 273 }
 274
 275 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 276 {
 277         struct net *net = sock_net(skb->sk);
 278         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 279         struct fib_rules_ops *ops = NULL;
 280         struct fib_rule *rule, *r, *last = NULL;
 281         struct nlattr *tb[FRA_MAX+1];
 282         int err = -EINVAL, unresolved = 0;
 283
 284         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 285                 goto errout;
 286
 287         ops = lookup_rules_ops(net, frh->family);
 288         if (ops == NULL) {
 289                 err = -EAFNOSUPPORT;
 290                 goto errout;
 291         }
 292
 293         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 294         if (err < 0)
 295                 goto errout;
 296
 297         err = validate_rulemsg(frh, tb, ops);
 298         if (err < 0)
 299                 goto errout;
 300
 301         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 302         if (rule == NULL) {
 303                 err = -ENOMEM;
 304                 goto errout;
 305         }
 306         rule->fr_net = hold_net(net);
 307
 308         if (tb[FRA_PRIORITY])
 309                 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 310
 311         if (tb[FRA_IIFNAME]) {
 312                 struct net_device *dev;
 313
 314                 rule->iifindex = -1;
 315                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 316                 dev = __dev_get_by_name(net, rule->iifname);
 317                 if (dev)
 318                         rule->iifindex = dev->ifindex;
 319         }
 320
 321         if (tb[FRA_OIFNAME]) {
 322                 struct net_device *dev;
 323
 324                 rule->oifindex = -1;
 325                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 326                 dev = __dev_get_by_name(net, rule->oifname);
 327                 if (dev)
 328                         rule->oifindex = dev->ifindex;
 329         }
 330
 331         if (tb[FRA_FWMARK]) {
 332                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 333                 if (rule->mark)
 334                         /* compatibility: if the mark value is non-zero all bits
 335                          * are compared unless a mask is explicitly specified.
 336                          */
 337                         rule->mark_mask = 0xFFFFFFFF;
 338         }
 339
 340         if (tb[FRA_FWMASK])
 341                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 342
 343         rule->action = frh->action;
 344         rule->flags = frh->flags;
 345         rule->table = frh_get_table(frh, tb);
 346         if (tb[FRA_SUPPRESS_PREFIXLEN])
 347                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 348         else
 349                 rule->suppress_prefixlen = -1;
 350
 351         if (tb[FRA_SUPPRESS_IFGROUP])
 352                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 353         else
 354                 rule->suppress_ifgroup = -1;
 355
 356         if (!tb[FRA_PRIORITY] && ops->default_pref)
 357                 rule->pref = ops->default_pref(ops);
 358
 359         err = -EINVAL;
 360         if (tb[FRA_GOTO]) {
 361                 if (rule->action != FR_ACT_GOTO)
 362                         goto errout_free;
 363
 364                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 365                 /* Backward jumps are prohibited to avoid endless loops */
 366                 if (rule->target <= rule->pref)
 367                         goto errout_free;
 368
 369                 list_for_each_entry(r, &ops->rules_list, list) {
 370                         if (r->pref == rule->target) {
 371                                 RCU_INIT_POINTER(rule->ctarget, r);
 372                                 break;
 373                         }
 374                 }
 375
 376                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 377                         unresolved = 1;
 378         } else if (rule->action == FR_ACT_GOTO)
 379                 goto errout_free;
 380
 381         err = ops->configure(rule, skb, frh, tb);
 382         if (err < 0)
 383                 goto errout_free;
 384
 385         list_for_each_entry(r, &ops->rules_list, list) {
 386                 if (r->pref > rule->pref)
 387                         break;
 388                 last = r;
 389         }
 390
 391         fib_rule_get(rule);
 392
 393         if (last)
 394                 list_add_rcu(&rule->list, &last->list);
 395         else
 396                 list_add_rcu(&rule->list, &ops->rules_list);
 397
 398         if (ops->unresolved_rules) {
 399                 /*
 400                  * There are unresolved goto rules in the list, check if
 401                  * any of them are pointing to this new rule.
 402                  */
 403                 list_for_each_entry(r, &ops->rules_list, list) {
 404                         if (r->action == FR_ACT_GOTO &&
 405                             r->target == rule->pref &&
 406                             rtnl_dereference(r->ctarget) == NULL) {
 407                                 rcu_assign_pointer(r->ctarget, rule);
 408                                 if (--ops->unresolved_rules == 0)
 409                                         break;
 410                         }
 411                 }
 412         }
 413
 414         if (rule->action == FR_ACT_GOTO)
 415                 ops->nr_goto_rules++;
 416
 417         if (unresolved)
 418                 ops->unresolved_rules++;
 419
 420         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 421         flush_route_cache(ops);
 422         rules_ops_put(ops);
 423         return 0;
 424
 425 errout_free:
 426         release_net(rule->fr_net);
 427         kfree(rule);
 428 errout:
 429         rules_ops_put(ops);
 430         return err;
 431 }
 432
 433 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 434 {
 435         struct net *net = sock_net(skb->sk);
 436         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 437         struct fib_rules_ops *ops = NULL;
 438         struct fib_rule *rule, *tmp;
 439         struct nlattr *tb[FRA_MAX+1];
 440         int err = -EINVAL;
 441
 442         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 443                 goto errout;
 444
 445         ops = lookup_rules_ops(net, frh->family);
 446         if (ops == NULL) {
 447                 err = -EAFNOSUPPORT;
 448                 goto errout;
 449         }
 450
 451         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 452         if (err < 0)
 453                 goto errout;
 454
 455         err = validate_rulemsg(frh, tb, ops);
 456         if (err < 0)
 457                 goto errout;
 458
 459         list_for_each_entry(rule, &ops->rules_list, list) {
 460                 if (frh->action && (frh->action != rule->action))
 461                         continue;
 462
 463                 if (frh_get_table(frh, tb) &&
 464                     (frh_get_table(frh, tb) != rule->table))
 465                         continue;
 466
 467                 if (tb[FRA_PRIORITY] &&
 468                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 469                         continue;
 470
 471                 if (tb[FRA_IIFNAME] &&
 472                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 473                         continue;
 474
 475                 if (tb[FRA_OIFNAME] &&
 476                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 477                         continue;
 478
 479                 if (tb[FRA_FWMARK] &&
 480                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 481                         continue;
 482
 483                 if (tb[FRA_FWMASK] &&
 484                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 485                         continue;
 486
 487                 if (!ops->compare(rule, frh, tb))
 488                         continue;
 489
 490                 if (rule->flags & FIB_RULE_PERMANENT) {
 491                         err = -EPERM;
 492                         goto errout;
 493                 }
 494
 495                 list_del_rcu(&rule->list);
 496
 497                 if (rule->action == FR_ACT_GOTO) {
 498                         ops->nr_goto_rules--;
 499                         if (rtnl_dereference(rule->ctarget) == NULL)
 500                                 ops->unresolved_rules--;
 501                 }
 502
 503                 /*
 504                  * Check if this rule is a target to any of them. If so,
 505                  * disable them. As this operation is eventually very
 506                  * expensive, it is only performed if goto rules have
 507                  * actually been added.
 508                  */
 509                 if (ops->nr_goto_rules > 0) {
 510                         list_for_each_entry(tmp, &ops->rules_list, list) {
 511                                 if (rtnl_dereference(tmp->ctarget) == rule) {
 512                                         RCU_INIT_POINTER(tmp->ctarget, NULL);
 513                                         ops->unresolved_rules++;
 514                                 }
 515                         }
 516                 }
 517
 518                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 519                                    NETLINK_CB(skb).portid);
 520                 if (ops->delete)
 521                         ops->delete(rule);
 522                 fib_rule_put(rule);
 523                 flush_route_cache(ops);
 524                 rules_ops_put(ops);
 525                 return 0;
 526         }
 527
 528         err = -ENOENT;
 529 errout:
 530         rules_ops_put(ops);
 531         return err;
 532 }
 533
 534 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 535                                          struct fib_rule *rule)
 536 {
 537         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 538                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 539                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 540                          + nla_total_size(4) /* FRA_PRIORITY */
 541                          + nla_total_size(4) /* FRA_TABLE */
 542                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 543                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 544                          + nla_total_size(4) /* FRA_FWMARK */
 545                          + nla_total_size(4); /* FRA_FWMASK */
 546
 547         if (ops->nlmsg_payload)
 548                 payload += ops->nlmsg_payload(rule);
 549
 550         return payload;
 551 }
 552
 553 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 554                             u32 pid, u32 seq, int type, int flags,
 555                             struct fib_rules_ops *ops)
 556 {
 557         struct nlmsghdr *nlh;
 558         struct fib_rule_hdr *frh;
 559
 560         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 561         if (nlh == NULL)
 562                 return -EMSGSIZE;
 563
 564         frh = nlmsg_data(nlh);
 565         frh->family = ops->family;
 566         frh->table = rule->table;
 567         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 568                 goto nla_put_failure;
 569         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 570                 goto nla_put_failure;
 571         frh->res1 = 0;
 572         frh->res2 = 0;
 573         frh->action = rule->action;
 574         frh->flags = rule->flags;
 575
 576         if (rule->action == FR_ACT_GOTO &&
 577             rcu_access_pointer(rule->ctarget) == NULL)
 578                 frh->flags |= FIB_RULE_UNRESOLVED;
 579
 580         if (rule->iifname[0]) {
 581                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 582                         goto nla_put_failure;
 583                 if (rule->iifindex == -1)
 584                         frh->flags |= FIB_RULE_IIF_DETACHED;
 585         }
 586
 587         if (rule->oifname[0]) {
 588                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 589                         goto nla_put_failure;
 590                 if (rule->oifindex == -1)
 591                         frh->flags |= FIB_RULE_OIF_DETACHED;
 592         }
 593
 594         if ((rule->pref &&
 595              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 596             (rule->mark &&
 597              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 598             ((rule->mark_mask || rule->mark) &&
 599              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 600             (rule->target &&
 601              nla_put_u32(skb, FRA_GOTO, rule->target)))
 602                 goto nla_put_failure;
 603
 604         if (rule->suppress_ifgroup != -1) {
 605                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 606                         goto nla_put_failure;
 607         }
 608
 609         if (ops->fill(rule, skb, frh) < 0)
 610                 goto nla_put_failure;
 611
 612         return nlmsg_end(skb, nlh);
 613
 614 nla_put_failure:
 615         nlmsg_cancel(skb, nlh);
 616         return -EMSGSIZE;
 617 }
 618
 619 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 620                       struct fib_rules_ops *ops)
 621 {
 622         int idx = 0;
 623         struct fib_rule *rule;
 624
 625         rcu_read_lock();
 626         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 627                 if (idx < cb->args[1])
 628                         goto skip;
 629
 630                 if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 631                                      cb->nlh->nlmsg_seq, RTM_NEWRULE,
 632                                      NLM_F_MULTI, ops) < 0)
 633                         break;
 634 skip:
 635                 idx++;
 636         }
 637         rcu_read_unlock();
 638         cb->args[1] = idx;
 639         rules_ops_put(ops);
 640
 641         return skb->len;
 642 }
 643
 644 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 645 {
 646         struct net *net = sock_net(skb->sk);
 647         struct fib_rules_ops *ops;
 648         int idx = 0, family;
 649
 650         family = rtnl_msg_family(cb->nlh);
 651         if (family != AF_UNSPEC) {
 652                 /* Protocol specific dump request */
 653                 ops = lookup_rules_ops(net, family);
 654                 if (ops == NULL)
 655                         return -EAFNOSUPPORT;
 656
 657                 return dump_rules(skb, cb, ops);
 658         }
 659
 660         rcu_read_lock();
 661         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 662                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 663                         goto skip;
 664
 665                 if (dump_rules(skb, cb, ops) < 0)
 666                         break;
 667
 668                 cb->args[1] = 0;
 669 skip:
 670                 idx++;
 671         }
 672         rcu_read_unlock();
 673         cb->args[0] = idx;
 674
 675         return skb->len;
 676 }
 677
 678 static void notify_rule_change(int event, struct fib_rule *rule,
 679                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 680                                u32 pid)
 681 {
 682         struct net *net;
 683         struct sk_buff *skb;
 684         int err = -ENOBUFS;
 685
 686         net = ops->fro_net;
 687         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 688         if (skb == NULL)
 689                 goto errout;
 690
 691         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 692         if (err < 0) {
 693                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 694                 WARN_ON(err == -EMSGSIZE);
 695                 kfree_skb(skb);
 696                 goto errout;
 697         }
 698
 699         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 700         return;
 701 errout:
 702         if (err < 0)
 703                 rtnl_set_sk_err(net, ops->nlgroup, err);
 704 }
 705
 706 static void attach_rules(struct list_head *rules, struct net_device *dev)
 707 {
 708         struct fib_rule *rule;
 709
 710         list_for_each_entry(rule, rules, list) {
 711                 if (rule->iifindex == -1 &&
 712                     strcmp(dev->name, rule->iifname) == 0)
 713                         rule->iifindex = dev->ifindex;
 714                 if (rule->oifindex == -1 &&
 715                     strcmp(dev->name, rule->oifname) == 0)
 716                         rule->oifindex = dev->ifindex;
 717         }
 718 }
 719
 720 static void detach_rules(struct list_head *rules, struct net_device *dev)
 721 {
 722         struct fib_rule *rule;
 723
 724         list_for_each_entry(rule, rules, list) {
 725                 if (rule->iifindex == dev->ifindex)
 726                         rule->iifindex = -1;
 727                 if (rule->oifindex == dev->ifindex)
 728                         rule->oifindex = -1;
 729         }
 730 }
 731
 732
 733 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 734                            void *ptr)
 735 {
 736         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 737         struct net *net = dev_net(dev);
 738         struct fib_rules_ops *ops;
 739
 740         ASSERT_RTNL();
 741
 742         switch (event) {
 743         case NETDEV_REGISTER:
 744                 list_for_each_entry(ops, &net->rules_ops, list)
 745                         attach_rules(&ops->rules_list, dev);
 746                 break;
 747
 748         case NETDEV_CHANGENAME:
 749                 list_for_each_entry(ops, &net->rules_ops, list) {
 750                         detach_rules(&ops->rules_list, dev);
 751                         attach_rules(&ops->rules_list, dev);
 752                 }
 753                 break;
 754
 755         case NETDEV_UNREGISTER:
 756                 list_for_each_entry(ops, &net->rules_ops, list)
 757                         detach_rules(&ops->rules_list, dev);
 758                 break;
 759         }
 760
 761         return NOTIFY_DONE;
 762 }
 763
 764 static struct notifier_block fib_rules_notifier = {
 765         .notifier_call = fib_rules_event,
 766 };
 767
 768 static int __net_init fib_rules_net_init(struct net *net)
 769 {
 770         INIT_LIST_HEAD(&net->rules_ops);
 771         spin_lock_init(&net->rules_mod_lock);
 772         return 0;
 773 }
 774
 775 static struct pernet_operations fib_rules_net_ops = {
 776         .init = fib_rules_net_init,
 777 };
 778
 779 static int __init fib_rules_init(void)
 780 {
 781         int err;
 782         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 783         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 784         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 785
 786         err = register_pernet_subsys(&fib_rules_net_ops);
 787         if (err < 0)
 788                 goto fail;
 789
 790         err = register_netdevice_notifier(&fib_rules_notifier);
 791         if (err < 0)
 792                 goto fail_unregister;
 793
 794         return 0;
 795
 796 fail_unregister:
 797         unregister_pernet_subsys(&fib_rules_net_ops);
 798 fail:
 799         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 800         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 801         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 802         return err;
 803 }
 804
 805 subsys_initcall(fib_rules_init);