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