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->uid_start = INVALID_UID;
  35         r->uid_end = INVALID_UID;
  36         r->fr_net = hold_net(ops->fro_net);
  37
  38         r->suppress_prefixlen = -1;
  39         r->suppress_ifgroup = -1;
  40
  41         /* The lock is not required here, the list in unreacheable
  42          * at the moment this function is called */
  43         list_add_tail(&r->list, &ops->rules_list);
  44         return 0;
  45 }
  46 EXPORT_SYMBOL(fib_default_rule_add);
  47
  48 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  49 {
  50         struct list_head *pos;
  51         struct fib_rule *rule;
  52
  53         if (!list_empty(&ops->rules_list)) {
  54                 pos = ops->rules_list.next;
  55                 if (pos->next != &ops->rules_list) {
  56                         rule = list_entry(pos->next, struct fib_rule, list);
  57                         if (rule->pref)
  58                                 return rule->pref - 1;
  59                 }
  60         }
  61
  62         return 0;
  63 }
  64 EXPORT_SYMBOL(fib_default_rule_pref);
  65
  66 static void notify_rule_change(int event, struct fib_rule *rule,
  67                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  68                                u32 pid);
  69
  70 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  71 {
  72         struct fib_rules_ops *ops;
  73
  74         rcu_read_lock();
  75         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  76                 if (ops->family == family) {
  77                         if (!try_module_get(ops->owner))
  78                                 ops = NULL;
  79                         rcu_read_unlock();
  80                         return ops;
  81                 }
  82         }
  83         rcu_read_unlock();
  84
  85         return NULL;
  86 }
  87
  88 static void rules_ops_put(struct fib_rules_ops *ops)
  89 {
  90         if (ops)
  91                 module_put(ops->owner);
  92 }
  93
  94 static void flush_route_cache(struct fib_rules_ops *ops)
  95 {
  96         if (ops->flush_cache)
  97                 ops->flush_cache(ops);
  98 }
  99
 100 static int __fib_rules_register(struct fib_rules_ops *ops)
 101 {
 102         int err = -EEXIST;
 103         struct fib_rules_ops *o;
 104         struct net *net;
 105
 106         net = ops->fro_net;
 107
 108         if (ops->rule_size < sizeof(struct fib_rule))
 109                 return -EINVAL;
 110
 111         if (ops->match == NULL || ops->configure == NULL ||
 112             ops->compare == NULL || ops->fill == NULL ||
 113             ops->action == NULL)
 114                 return -EINVAL;
 115
 116         spin_lock(&net->rules_mod_lock);
 117         list_for_each_entry(o, &net->rules_ops, list)
 118                 if (ops->family == o->family)
 119                         goto errout;
 120
 121         hold_net(net);
 122         list_add_tail_rcu(&ops->list, &net->rules_ops);
 123         err = 0;
 124 errout:
 125         spin_unlock(&net->rules_mod_lock);
 126
 127         return err;
 128 }
 129
 130 struct fib_rules_ops *
 131 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 132 {
 133         struct fib_rules_ops *ops;
 134         int err;
 135
 136         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 137         if (ops == NULL)
 138                 return ERR_PTR(-ENOMEM);
 139
 140         INIT_LIST_HEAD(&ops->rules_list);
 141         ops->fro_net = net;
 142
 143         err = __fib_rules_register(ops);
 144         if (err) {
 145                 kfree(ops);
 146                 ops = ERR_PTR(err);
 147         }
 148
 149         return ops;
 150 }
 151 EXPORT_SYMBOL_GPL(fib_rules_register);
 152
 153 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 154 {
 155         struct fib_rule *rule, *tmp;
 156
 157         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 158                 list_del_rcu(&rule->list);
 159                 if (ops->delete)
 160                         ops->delete(rule);
 161                 fib_rule_put(rule);
 162         }
 163 }
 164
 165 static void fib_rules_put_rcu(struct rcu_head *head)
 166 {
 167         struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
 168         struct net *net = ops->fro_net;
 169
 170         release_net(net);
 171         kfree(ops);
 172 }
 173
 174 void fib_rules_unregister(struct fib_rules_ops *ops)
 175 {
 176         struct net *net = ops->fro_net;
 177
 178         spin_lock(&net->rules_mod_lock);
 179         list_del_rcu(&ops->list);
 180         fib_rules_cleanup_ops(ops);
 181         spin_unlock(&net->rules_mod_lock);
 182
 183         call_rcu(&ops->rcu, fib_rules_put_rcu);
 184 }
 185 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 186
 187 static inline kuid_t fib_nl_uid(struct nlattr *nla)
 188 {
 189         return make_kuid(current_user_ns(), nla_get_u32(nla));
 190 }
 191
 192 static int nla_put_uid(struct sk_buff *skb, int idx, kuid_t uid)
 193 {
 194         return nla_put_u32(skb, idx, from_kuid_munged(current_user_ns(), uid));
 195 }
 196
 197 static int fib_uid_range_match(struct flowi *fl, struct fib_rule *rule)
 198 {
 199         return (!uid_valid(rule->uid_start) && !uid_valid(rule->uid_end)) ||
 200                (uid_gte(fl->flowi_uid, rule->uid_start) &&
 201                 uid_lte(fl->flowi_uid, rule->uid_end));
 202 }
 203
 204 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 205                           struct flowi *fl, int flags)
 206 {
 207         int ret = 0;
 208
 209         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 210                 goto out;
 211
 212         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 213                 goto out;
 214
 215         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 216                 goto out;
 217
 218         if (!fib_uid_range_match(fl, rule))
 219                 goto out;
 220
 221         ret = ops->match(rule, fl, flags);
 222 out:
 223         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 224 }
 225
 226 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 227                      int flags, struct fib_lookup_arg *arg)
 228 {
 229         struct fib_rule *rule;
 230         int err;
 231
 232         rcu_read_lock();
 233
 234         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 235 jumped:
 236                 if (!fib_rule_match(rule, ops, fl, flags))
 237                         continue;
 238
 239                 if (rule->action == FR_ACT_GOTO) {
 240                         struct fib_rule *target;
 241
 242                         target = rcu_dereference(rule->ctarget);
 243                         if (target == NULL) {
 244                                 continue;
 245                         } else {
 246                                 rule = target;
 247                                 goto jumped;
 248                         }
 249                 } else if (rule->action == FR_ACT_NOP)
 250                         continue;
 251                 else
 252                         err = ops->action(rule, fl, flags, arg);
 253
 254                 if (!err && ops->suppress && ops->suppress(rule, arg))
 255                         continue;
 256
 257                 if (err != -EAGAIN) {
 258                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 259                             likely(atomic_inc_not_zero(&rule->refcnt))) {
 260                                 arg->rule = rule;
 261                                 goto out;
 262                         }
 263                         break;
 264                 }
 265         }
 266
 267         err = -ESRCH;
 268 out:
 269         rcu_read_unlock();
 270
 271         return err;
 272 }
 273 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 274
 275 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 276                             struct fib_rules_ops *ops)
 277 {
 278         int err = -EINVAL;
 279
 280         if (frh->src_len)
 281                 if (tb[FRA_SRC] == NULL ||
 282                     frh->src_len > (ops->addr_size * 8) ||
 283                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 284                         goto errout;
 285
 286         if (frh->dst_len)
 287                 if (tb[FRA_DST] == NULL ||
 288                     frh->dst_len > (ops->addr_size * 8) ||
 289                     nla_len(tb[FRA_DST]) != ops->addr_size)
 290                         goto errout;
 291
 292         err = 0;
 293 errout:
 294         return err;
 295 }
 296
 297 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 298 {
 299         struct net *net = sock_net(skb->sk);
 300         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 301         struct fib_rules_ops *ops = NULL;
 302         struct fib_rule *rule, *r, *last = NULL;
 303         struct nlattr *tb[FRA_MAX+1];
 304         int err = -EINVAL, unresolved = 0;
 305
 306         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 307                 goto errout;
 308
 309         ops = lookup_rules_ops(net, frh->family);
 310         if (ops == NULL) {
 311                 err = -EAFNOSUPPORT;
 312                 goto errout;
 313         }
 314
 315         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 316         if (err < 0)
 317                 goto errout;
 318
 319         err = validate_rulemsg(frh, tb, ops);
 320         if (err < 0)
 321                 goto errout;
 322
 323         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 324         if (rule == NULL) {
 325                 err = -ENOMEM;
 326                 goto errout;
 327         }
 328         rule->fr_net = hold_net(net);
 329
 330         if (tb[FRA_PRIORITY])
 331                 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 332
 333         if (tb[FRA_IIFNAME]) {
 334                 struct net_device *dev;
 335
 336                 rule->iifindex = -1;
 337                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 338                 dev = __dev_get_by_name(net, rule->iifname);
 339                 if (dev)
 340                         rule->iifindex = dev->ifindex;
 341         }
 342
 343         if (tb[FRA_OIFNAME]) {
 344                 struct net_device *dev;
 345
 346                 rule->oifindex = -1;
 347                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 348                 dev = __dev_get_by_name(net, rule->oifname);
 349                 if (dev)
 350                         rule->oifindex = dev->ifindex;
 351         }
 352
 353         if (tb[FRA_FWMARK]) {
 354                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 355                 if (rule->mark)
 356                         /* compatibility: if the mark value is non-zero all bits
 357                          * are compared unless a mask is explicitly specified.
 358                          */
 359                         rule->mark_mask = 0xFFFFFFFF;
 360         }
 361
 362         if (tb[FRA_FWMASK])
 363                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 364
 365         rule->action = frh->action;
 366         rule->flags = frh->flags;
 367         rule->table = frh_get_table(frh, tb);
 368         if (tb[FRA_SUPPRESS_PREFIXLEN])
 369                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 370         else
 371                 rule->suppress_prefixlen = -1;
 372
 373         if (tb[FRA_SUPPRESS_IFGROUP])
 374                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 375         else
 376                 rule->suppress_ifgroup = -1;
 377
 378         if (!tb[FRA_PRIORITY] && ops->default_pref)
 379                 rule->pref = ops->default_pref(ops);
 380
 381         err = -EINVAL;
 382         if (tb[FRA_GOTO]) {
 383                 if (rule->action != FR_ACT_GOTO)
 384                         goto errout_free;
 385
 386                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 387                 /* Backward jumps are prohibited to avoid endless loops */
 388                 if (rule->target <= rule->pref)
 389                         goto errout_free;
 390
 391                 list_for_each_entry(r, &ops->rules_list, list) {
 392                         if (r->pref == rule->target) {
 393                                 RCU_INIT_POINTER(rule->ctarget, r);
 394                                 break;
 395                         }
 396                 }
 397
 398                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 399                         unresolved = 1;
 400         } else if (rule->action == FR_ACT_GOTO)
 401                 goto errout_free;
 402
 403         /* UID start and end must either both be valid or both unspecified. */
 404         rule->uid_start = rule->uid_end = INVALID_UID;
 405         if (tb[FRA_UID_START] || tb[FRA_UID_END]) {
 406                 if (tb[FRA_UID_START] && tb[FRA_UID_END]) {
 407                         rule->uid_start = fib_nl_uid(tb[FRA_UID_START]);
 408                         rule->uid_end = fib_nl_uid(tb[FRA_UID_END]);
 409                 }
 410                 if (!uid_valid(rule->uid_start) ||
 411                     !uid_valid(rule->uid_end) ||
 412                     !uid_lte(rule->uid_start, rule->uid_end))
 413                 goto errout_free;
 414         }
 415
 416         err = ops->configure(rule, skb, frh, tb);
 417         if (err < 0)
 418                 goto errout_free;
 419
 420         list_for_each_entry(r, &ops->rules_list, list) {
 421                 if (r->pref > rule->pref)
 422                         break;
 423                 last = r;
 424         }
 425
 426         fib_rule_get(rule);
 427
 428         if (last)
 429                 list_add_rcu(&rule->list, &last->list);
 430         else
 431                 list_add_rcu(&rule->list, &ops->rules_list);
 432
 433         if (ops->unresolved_rules) {
 434                 /*
 435                  * There are unresolved goto rules in the list, check if
 436                  * any of them are pointing to this new rule.
 437                  */
 438                 list_for_each_entry(r, &ops->rules_list, list) {
 439                         if (r->action == FR_ACT_GOTO &&
 440                             r->target == rule->pref &&
 441                             rtnl_dereference(r->ctarget) == NULL) {
 442                                 rcu_assign_pointer(r->ctarget, rule);
 443                                 if (--ops->unresolved_rules == 0)
 444                                         break;
 445                         }
 446                 }
 447         }
 448
 449         if (rule->action == FR_ACT_GOTO)
 450                 ops->nr_goto_rules++;
 451
 452         if (unresolved)
 453                 ops->unresolved_rules++;
 454
 455         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 456         flush_route_cache(ops);
 457         rules_ops_put(ops);
 458         return 0;
 459
 460 errout_free:
 461         release_net(rule->fr_net);
 462         kfree(rule);
 463 errout:
 464         rules_ops_put(ops);
 465         return err;
 466 }
 467
 468 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 469 {
 470         struct net *net = sock_net(skb->sk);
 471         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 472         struct fib_rules_ops *ops = NULL;
 473         struct fib_rule *rule, *tmp;
 474         struct nlattr *tb[FRA_MAX+1];
 475         int err = -EINVAL;
 476
 477         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 478                 goto errout;
 479
 480         ops = lookup_rules_ops(net, frh->family);
 481         if (ops == NULL) {
 482                 err = -EAFNOSUPPORT;
 483                 goto errout;
 484         }
 485
 486         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 487         if (err < 0)
 488                 goto errout;
 489
 490         err = validate_rulemsg(frh, tb, ops);
 491         if (err < 0)
 492                 goto errout;
 493
 494         list_for_each_entry(rule, &ops->rules_list, list) {
 495                 if (frh->action && (frh->action != rule->action))
 496                         continue;
 497
 498                 if (frh_get_table(frh, tb) &&
 499                     (frh_get_table(frh, tb) != rule->table))
 500                         continue;
 501
 502                 if (tb[FRA_PRIORITY] &&
 503                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 504                         continue;
 505
 506                 if (tb[FRA_IIFNAME] &&
 507                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 508                         continue;
 509
 510                 if (tb[FRA_OIFNAME] &&
 511                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 512                         continue;
 513
 514                 if (tb[FRA_FWMARK] &&
 515                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 516                         continue;
 517
 518                 if (tb[FRA_FWMASK] &&
 519                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 520                         continue;
 521
 522                 if (tb[FRA_UID_START] &&
 523                     !uid_eq(rule->uid_start, fib_nl_uid(tb[FRA_UID_START])))
 524                         continue;
 525
 526                 if (tb[FRA_UID_END] &&
 527                     !uid_eq(rule->uid_end, fib_nl_uid(tb[FRA_UID_END])))
 528                         continue;
 529
 530                 if (!ops->compare(rule, frh, tb))
 531                         continue;
 532
 533                 if (rule->flags & FIB_RULE_PERMANENT) {
 534                         err = -EPERM;
 535                         goto errout;
 536                 }
 537
 538                 list_del_rcu(&rule->list);
 539
 540                 if (rule->action == FR_ACT_GOTO) {
 541                         ops->nr_goto_rules--;
 542                         if (rtnl_dereference(rule->ctarget) == NULL)
 543                                 ops->unresolved_rules--;
 544                 }
 545
 546                 /*
 547                  * Check if this rule is a target to any of them. If so,
 548                  * disable them. As this operation is eventually very
 549                  * expensive, it is only performed if goto rules have
 550                  * actually been added.
 551                  */
 552                 if (ops->nr_goto_rules > 0) {
 553                         list_for_each_entry(tmp, &ops->rules_list, list) {
 554                                 if (rtnl_dereference(tmp->ctarget) == rule) {
 555                                         RCU_INIT_POINTER(tmp->ctarget, NULL);
 556                                         ops->unresolved_rules++;
 557                                 }
 558                         }
 559                 }
 560
 561                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 562                                    NETLINK_CB(skb).portid);
 563                 if (ops->delete)
 564                         ops->delete(rule);
 565                 fib_rule_put(rule);
 566                 flush_route_cache(ops);
 567                 rules_ops_put(ops);
 568                 return 0;
 569         }
 570
 571         err = -ENOENT;
 572 errout:
 573         rules_ops_put(ops);
 574         return err;
 575 }
 576
 577 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 578                                          struct fib_rule *rule)
 579 {
 580         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 581                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 582                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 583                          + nla_total_size(4) /* FRA_PRIORITY */
 584                          + nla_total_size(4) /* FRA_TABLE */
 585                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 586                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 587                          + nla_total_size(4) /* FRA_FWMARK */
 588                          + nla_total_size(4) /* FRA_FWMASK */
 589                          + nla_total_size(4) /* FRA_UID_START */
 590                          + nla_total_size(4); /* FRA_UID_END */
 591
 592         if (ops->nlmsg_payload)
 593                 payload += ops->nlmsg_payload(rule);
 594
 595         return payload;
 596 }
 597
 598 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 599                             u32 pid, u32 seq, int type, int flags,
 600                             struct fib_rules_ops *ops)
 601 {
 602         struct nlmsghdr *nlh;
 603         struct fib_rule_hdr *frh;
 604
 605         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 606         if (nlh == NULL)
 607                 return -EMSGSIZE;
 608
 609         frh = nlmsg_data(nlh);
 610         frh->family = ops->family;
 611         frh->table = rule->table;
 612         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 613                 goto nla_put_failure;
 614         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 615                 goto nla_put_failure;
 616         frh->res1 = 0;
 617         frh->res2 = 0;
 618         frh->action = rule->action;
 619         frh->flags = rule->flags;
 620
 621         if (rule->action == FR_ACT_GOTO &&
 622             rcu_access_pointer(rule->ctarget) == NULL)
 623                 frh->flags |= FIB_RULE_UNRESOLVED;
 624
 625         if (rule->iifname[0]) {
 626                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 627                         goto nla_put_failure;
 628                 if (rule->iifindex == -1)
 629                         frh->flags |= FIB_RULE_IIF_DETACHED;
 630         }
 631
 632         if (rule->oifname[0]) {
 633                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 634                         goto nla_put_failure;
 635                 if (rule->oifindex == -1)
 636                         frh->flags |= FIB_RULE_OIF_DETACHED;
 637         }
 638
 639         if ((rule->pref &&
 640              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 641             (rule->mark &&
 642              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 643             ((rule->mark_mask || rule->mark) &&
 644              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 645             (rule->target &&
 646              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 647             (uid_valid(rule->uid_start) &&
 648              nla_put_uid(skb, FRA_UID_START, rule->uid_start)) ||
 649             (uid_valid(rule->uid_end) &&
 650              nla_put_uid(skb, FRA_UID_END, rule->uid_end)))
 651                 goto nla_put_failure;
 652
 653         if (rule->suppress_ifgroup != -1) {
 654                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 655                         goto nla_put_failure;
 656         }
 657
 658         if (ops->fill(rule, skb, frh) < 0)
 659                 goto nla_put_failure;
 660
 661         return nlmsg_end(skb, nlh);
 662
 663 nla_put_failure:
 664         nlmsg_cancel(skb, nlh);
 665         return -EMSGSIZE;
 666 }
 667
 668 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 669                       struct fib_rules_ops *ops)
 670 {
 671         int idx = 0;
 672         struct fib_rule *rule;
 673
 674         rcu_read_lock();
 675         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 676                 if (idx < cb->args[1])
 677                         goto skip;
 678
 679                 if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 680                                      cb->nlh->nlmsg_seq, RTM_NEWRULE,
 681                                      NLM_F_MULTI, ops) < 0)
 682                         break;
 683 skip:
 684                 idx++;
 685         }
 686         rcu_read_unlock();
 687         cb->args[1] = idx;
 688         rules_ops_put(ops);
 689
 690         return skb->len;
 691 }
 692
 693 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 694 {
 695         struct net *net = sock_net(skb->sk);
 696         struct fib_rules_ops *ops;
 697         int idx = 0, family;
 698
 699         family = rtnl_msg_family(cb->nlh);
 700         if (family != AF_UNSPEC) {
 701                 /* Protocol specific dump request */
 702                 ops = lookup_rules_ops(net, family);
 703                 if (ops == NULL)
 704                         return -EAFNOSUPPORT;
 705
 706                 return dump_rules(skb, cb, ops);
 707         }
 708
 709         rcu_read_lock();
 710         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 711                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 712                         goto skip;
 713
 714                 if (dump_rules(skb, cb, ops) < 0)
 715                         break;
 716
 717                 cb->args[1] = 0;
 718 skip:
 719                 idx++;
 720         }
 721         rcu_read_unlock();
 722         cb->args[0] = idx;
 723
 724         return skb->len;
 725 }
 726
 727 static void notify_rule_change(int event, struct fib_rule *rule,
 728                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 729                                u32 pid)
 730 {
 731         struct net *net;
 732         struct sk_buff *skb;
 733         int err = -ENOBUFS;
 734
 735         net = ops->fro_net;
 736         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 737         if (skb == NULL)
 738                 goto errout;
 739
 740         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 741         if (err < 0) {
 742                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 743                 WARN_ON(err == -EMSGSIZE);
 744                 kfree_skb(skb);
 745                 goto errout;
 746         }
 747
 748         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 749         return;
 750 errout:
 751         if (err < 0)
 752                 rtnl_set_sk_err(net, ops->nlgroup, err);
 753 }
 754
 755 static void attach_rules(struct list_head *rules, struct net_device *dev)
 756 {
 757         struct fib_rule *rule;
 758
 759         list_for_each_entry(rule, rules, list) {
 760                 if (rule->iifindex == -1 &&
 761                     strcmp(dev->name, rule->iifname) == 0)
 762                         rule->iifindex = dev->ifindex;
 763                 if (rule->oifindex == -1 &&
 764                     strcmp(dev->name, rule->oifname) == 0)
 765                         rule->oifindex = dev->ifindex;
 766         }
 767 }
 768
 769 static void detach_rules(struct list_head *rules, struct net_device *dev)
 770 {
 771         struct fib_rule *rule;
 772
 773         list_for_each_entry(rule, rules, list) {
 774                 if (rule->iifindex == dev->ifindex)
 775                         rule->iifindex = -1;
 776                 if (rule->oifindex == dev->ifindex)
 777                         rule->oifindex = -1;
 778         }
 779 }
 780
 781
 782 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 783                            void *ptr)
 784 {
 785         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 786         struct net *net = dev_net(dev);
 787         struct fib_rules_ops *ops;
 788
 789         ASSERT_RTNL();
 790
 791         switch (event) {
 792         case NETDEV_REGISTER:
 793                 list_for_each_entry(ops, &net->rules_ops, list)
 794                         attach_rules(&ops->rules_list, dev);
 795                 break;
 796
 797         case NETDEV_CHANGENAME:
 798                 list_for_each_entry(ops, &net->rules_ops, list) {
 799                         detach_rules(&ops->rules_list, dev);
 800                         attach_rules(&ops->rules_list, dev);
 801                 }
 802                 break;
 803
 804         case NETDEV_UNREGISTER:
 805                 list_for_each_entry(ops, &net->rules_ops, list)
 806                         detach_rules(&ops->rules_list, dev);
 807                 break;
 808         }
 809
 810         return NOTIFY_DONE;
 811 }
 812
 813 static struct notifier_block fib_rules_notifier = {
 814         .notifier_call = fib_rules_event,
 815 };
 816
 817 static int __net_init fib_rules_net_init(struct net *net)
 818 {
 819         INIT_LIST_HEAD(&net->rules_ops);
 820         spin_lock_init(&net->rules_mod_lock);
 821         return 0;
 822 }
 823
 824 static struct pernet_operations fib_rules_net_ops = {
 825         .init = fib_rules_net_init,
 826 };
 827
 828 static int __init fib_rules_init(void)
 829 {
 830         int err;
 831         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 832         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 833         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 834
 835         err = register_pernet_subsys(&fib_rules_net_ops);
 836         if (err < 0)
 837                 goto fail;
 838
 839         err = register_netdevice_notifier(&fib_rules_notifier);
 840         if (err < 0)
 841                 goto fail_unregister;
 842
 843         return 0;
 844
 845 fail_unregister:
 846         unregister_pernet_subsys(&fib_rules_net_ops);
 847 fail:
 848         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 849         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 850         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 851         return err;
 852 }
 853
 854 subsys_initcall(fib_rules_init);