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