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 #include <net/ip_tunnels.h>
  20
  21 static const struct fib_kuid_range fib_kuid_range_unset = {
  22         KUIDT_INIT(0),
  23         KUIDT_INIT(~0),
  24 };
  25
  26 bool fib_rule_matchall(const struct fib_rule *rule)
  27 {
  28         if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
  29             rule->flags)
  30                 return false;
  31         if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
  32                 return false;
  33         if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
  34             !uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
  35                 return false;
  36         return true;
  37 }
  38 EXPORT_SYMBOL_GPL(fib_rule_matchall);
  39
  40 int fib_default_rule_add(struct fib_rules_ops *ops,
  41                          u32 pref, u32 table, u32 flags)
  42 {
  43         struct fib_rule *r;
  44
  45         r = kzalloc(ops->rule_size, GFP_KERNEL);
  46         if (r == NULL)
  47                 return -ENOMEM;
  48
  49         refcount_set(&r->refcnt, 1);
  50         r->action = FR_ACT_TO_TBL;
  51         r->pref = pref;
  52         r->table = table;
  53         r->flags = flags;
  54         r->fr_net = ops->fro_net;
  55         r->uid_range = fib_kuid_range_unset;
  56
  57         r->suppress_prefixlen = -1;
  58         r->suppress_ifgroup = -1;
  59
  60         /* The lock is not required here, the list in unreacheable
  61          * at the moment this function is called */
  62         list_add_tail(&r->list, &ops->rules_list);
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(fib_default_rule_add);
  66
  67 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  68 {
  69         struct list_head *pos;
  70         struct fib_rule *rule;
  71
  72         if (!list_empty(&ops->rules_list)) {
  73                 pos = ops->rules_list.next;
  74                 if (pos->next != &ops->rules_list) {
  75                         rule = list_entry(pos->next, struct fib_rule, list);
  76                         if (rule->pref)
  77                                 return rule->pref - 1;
  78                 }
  79         }
  80
  81         return 0;
  82 }
  83
  84 static void notify_rule_change(int event, struct fib_rule *rule,
  85                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  86                                u32 pid);
  87
  88 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  89 {
  90         struct fib_rules_ops *ops;
  91
  92         rcu_read_lock();
  93         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  94                 if (ops->family == family) {
  95                         if (!try_module_get(ops->owner))
  96                                 ops = NULL;
  97                         rcu_read_unlock();
  98                         return ops;
  99                 }
 100         }
 101         rcu_read_unlock();
 102
 103         return NULL;
 104 }
 105
 106 static void rules_ops_put(struct fib_rules_ops *ops)
 107 {
 108         if (ops)
 109                 module_put(ops->owner);
 110 }
 111
 112 static void flush_route_cache(struct fib_rules_ops *ops)
 113 {
 114         if (ops->flush_cache)
 115                 ops->flush_cache(ops);
 116 }
 117
 118 static int __fib_rules_register(struct fib_rules_ops *ops)
 119 {
 120         int err = -EEXIST;
 121         struct fib_rules_ops *o;
 122         struct net *net;
 123
 124         net = ops->fro_net;
 125
 126         if (ops->rule_size < sizeof(struct fib_rule))
 127                 return -EINVAL;
 128
 129         if (ops->match == NULL || ops->configure == NULL ||
 130             ops->compare == NULL || ops->fill == NULL ||
 131             ops->action == NULL)
 132                 return -EINVAL;
 133
 134         spin_lock(&net->rules_mod_lock);
 135         list_for_each_entry(o, &net->rules_ops, list)
 136                 if (ops->family == o->family)
 137                         goto errout;
 138
 139         list_add_tail_rcu(&ops->list, &net->rules_ops);
 140         err = 0;
 141 errout:
 142         spin_unlock(&net->rules_mod_lock);
 143
 144         return err;
 145 }
 146
 147 struct fib_rules_ops *
 148 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 149 {
 150         struct fib_rules_ops *ops;
 151         int err;
 152
 153         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 154         if (ops == NULL)
 155                 return ERR_PTR(-ENOMEM);
 156
 157         INIT_LIST_HEAD(&ops->rules_list);
 158         ops->fro_net = net;
 159
 160         err = __fib_rules_register(ops);
 161         if (err) {
 162                 kfree(ops);
 163                 ops = ERR_PTR(err);
 164         }
 165
 166         return ops;
 167 }
 168 EXPORT_SYMBOL_GPL(fib_rules_register);
 169
 170 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 171 {
 172         struct fib_rule *rule, *tmp;
 173
 174         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 175                 list_del_rcu(&rule->list);
 176                 if (ops->delete)
 177                         ops->delete(rule);
 178                 fib_rule_put(rule);
 179         }
 180 }
 181
 182 void fib_rules_unregister(struct fib_rules_ops *ops)
 183 {
 184         struct net *net = ops->fro_net;
 185
 186         spin_lock(&net->rules_mod_lock);
 187         list_del_rcu(&ops->list);
 188         spin_unlock(&net->rules_mod_lock);
 189
 190         fib_rules_cleanup_ops(ops);
 191         kfree_rcu(ops, rcu);
 192 }
 193 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 194
 195 static int uid_range_set(struct fib_kuid_range *range)
 196 {
 197         return uid_valid(range->start) && uid_valid(range->end);
 198 }
 199
 200 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
 201 {
 202         struct fib_rule_uid_range *in;
 203         struct fib_kuid_range out;
 204
 205         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
 206
 207         out.start = make_kuid(current_user_ns(), in->start);
 208         out.end = make_kuid(current_user_ns(), in->end);
 209
 210         return out;
 211 }
 212
 213 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
 214 {
 215         struct fib_rule_uid_range out = {
 216                 from_kuid_munged(current_user_ns(), range->start),
 217                 from_kuid_munged(current_user_ns(), range->end)
 218         };
 219
 220         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
 221 }
 222
 223 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 224                           struct flowi *fl, int flags,
 225                           struct fib_lookup_arg *arg)
 226 {
 227         int ret = 0;
 228
 229         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 230                 goto out;
 231
 232         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 233                 goto out;
 234
 235         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 236                 goto out;
 237
 238         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
 239                 goto out;
 240
 241         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
 242                 goto out;
 243
 244         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
 245             uid_gt(fl->flowi_uid, rule->uid_range.end))
 246                 goto out;
 247
 248         ret = ops->match(rule, fl, flags);
 249 out:
 250         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 251 }
 252
 253 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 254                      int flags, struct fib_lookup_arg *arg)
 255 {
 256         struct fib_rule *rule;
 257         int err;
 258
 259         rcu_read_lock();
 260
 261         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 262 jumped:
 263                 if (!fib_rule_match(rule, ops, fl, flags, arg))
 264                         continue;
 265
 266                 if (rule->action == FR_ACT_GOTO) {
 267                         struct fib_rule *target;
 268
 269                         target = rcu_dereference(rule->ctarget);
 270                         if (target == NULL) {
 271                                 continue;
 272                         } else {
 273                                 rule = target;
 274                                 goto jumped;
 275                         }
 276                 } else if (rule->action == FR_ACT_NOP)
 277                         continue;
 278                 else
 279                         err = ops->action(rule, fl, flags, arg);
 280
 281                 if (!err && ops->suppress && ops->suppress(rule, arg))
 282                         continue;
 283
 284                 if (err != -EAGAIN) {
 285                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 286                             likely(refcount_inc_not_zero(&rule->refcnt))) {
 287                                 arg->rule = rule;
 288                                 goto out;
 289                         }
 290                         break;
 291                 }
 292         }
 293
 294         err = -ESRCH;
 295 out:
 296         rcu_read_unlock();
 297
 298         return err;
 299 }
 300 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 301
 302 static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
 303                                   enum fib_event_type event_type,
 304                                   struct fib_rule *rule, int family)
 305 {
 306         struct fib_rule_notifier_info info = {
 307                 .info.family = family,
 308                 .rule = rule,
 309         };
 310
 311         return call_fib_notifier(nb, net, event_type, &info.info);
 312 }
 313
 314 static int call_fib_rule_notifiers(struct net *net,
 315                                    enum fib_event_type event_type,
 316                                    struct fib_rule *rule,
 317                                    struct fib_rules_ops *ops)
 318 {
 319         struct fib_rule_notifier_info info = {
 320                 .info.family = ops->family,
 321                 .rule = rule,
 322         };
 323
 324         ops->fib_rules_seq++;
 325         return call_fib_notifiers(net, event_type, &info.info);
 326 }
 327
 328 /* Called with rcu_read_lock() */
 329 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
 330 {
 331         struct fib_rules_ops *ops;
 332         struct fib_rule *rule;
 333
 334         ops = lookup_rules_ops(net, family);
 335         if (!ops)
 336                 return -EAFNOSUPPORT;
 337         list_for_each_entry_rcu(rule, &ops->rules_list, list)
 338                 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
 339                                        family);
 340         rules_ops_put(ops);
 341
 342         return 0;
 343 }
 344 EXPORT_SYMBOL_GPL(fib_rules_dump);
 345
 346 unsigned int fib_rules_seq_read(struct net *net, int family)
 347 {
 348         unsigned int fib_rules_seq;
 349         struct fib_rules_ops *ops;
 350
 351         ASSERT_RTNL();
 352
 353         ops = lookup_rules_ops(net, family);
 354         if (!ops)
 355                 return 0;
 356         fib_rules_seq = ops->fib_rules_seq;
 357         rules_ops_put(ops);
 358
 359         return fib_rules_seq;
 360 }
 361 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 362
 363 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 364                             struct fib_rules_ops *ops)
 365 {
 366         int err = -EINVAL;
 367
 368         if (frh->src_len)
 369                 if (tb[FRA_SRC] == NULL ||
 370                     frh->src_len > (ops->addr_size * 8) ||
 371                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 372                         goto errout;
 373
 374         if (frh->dst_len)
 375                 if (tb[FRA_DST] == NULL ||
 376                     frh->dst_len > (ops->addr_size * 8) ||
 377                     nla_len(tb[FRA_DST]) != ops->addr_size)
 378                         goto errout;
 379
 380         err = 0;
 381 errout:
 382         return err;
 383 }
 384
 385 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 386                        struct nlattr **tb, struct fib_rule *rule)
 387 {
 388         struct fib_rule *r;
 389
 390         list_for_each_entry(r, &ops->rules_list, list) {
 391                 if (r->action != rule->action)
 392                         continue;
 393
 394                 if (r->table != rule->table)
 395                         continue;
 396
 397                 if (r->pref != rule->pref)
 398                         continue;
 399
 400                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 401                         continue;
 402
 403                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 404                         continue;
 405
 406                 if (r->mark != rule->mark)
 407                         continue;
 408
 409                 if (r->mark_mask != rule->mark_mask)
 410                         continue;
 411
 412                 if (r->tun_id != rule->tun_id)
 413                         continue;
 414
 415                 if (r->fr_net != rule->fr_net)
 416                         continue;
 417
 418                 if (r->l3mdev != rule->l3mdev)
 419                         continue;
 420
 421                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 422                     !uid_eq(r->uid_range.end, rule->uid_range.end))
 423                         continue;
 424
 425                 if (!ops->compare(r, frh, tb))
 426                         continue;
 427                 return 1;
 428         }
 429         return 0;
 430 }
 431
 432 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 433                    struct netlink_ext_ack *extack)
 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, *r, *last = NULL;
 439         struct nlattr *tb[FRA_MAX+1];
 440         int err = -EINVAL, unresolved = 0;
 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, extack);
 452         if (err < 0)
 453                 goto errout;
 454
 455         err = validate_rulemsg(frh, tb, ops);
 456         if (err < 0)
 457                 goto errout;
 458
 459         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 460         if (rule == NULL) {
 461                 err = -ENOMEM;
 462                 goto errout;
 463         }
 464         refcount_set(&rule->refcnt, 1);
 465         rule->fr_net = net;
 466
 467         rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 468                                       : fib_default_rule_pref(ops);
 469
 470         if (tb[FRA_IIFNAME]) {
 471                 struct net_device *dev;
 472
 473                 rule->iifindex = -1;
 474                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 475                 dev = __dev_get_by_name(net, rule->iifname);
 476                 if (dev)
 477                         rule->iifindex = dev->ifindex;
 478         }
 479
 480         if (tb[FRA_OIFNAME]) {
 481                 struct net_device *dev;
 482
 483                 rule->oifindex = -1;
 484                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 485                 dev = __dev_get_by_name(net, rule->oifname);
 486                 if (dev)
 487                         rule->oifindex = dev->ifindex;
 488         }
 489
 490         if (tb[FRA_FWMARK]) {
 491                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 492                 if (rule->mark)
 493                         /* compatibility: if the mark value is non-zero all bits
 494                          * are compared unless a mask is explicitly specified.
 495                          */
 496                         rule->mark_mask = 0xFFFFFFFF;
 497         }
 498
 499         if (tb[FRA_FWMASK])
 500                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 501
 502         if (tb[FRA_TUN_ID])
 503                 rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 504
 505         err = -EINVAL;
 506         if (tb[FRA_L3MDEV]) {
 507 #ifdef CONFIG_NET_L3_MASTER_DEV
 508                 rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
 509                 if (rule->l3mdev != 1)
 510 #endif
 511                         goto errout_free;
 512         }
 513
 514         rule->action = frh->action;
 515         rule->flags = frh->flags;
 516         rule->table = frh_get_table(frh, tb);
 517         if (tb[FRA_SUPPRESS_PREFIXLEN])
 518                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 519         else
 520                 rule->suppress_prefixlen = -1;
 521
 522         if (tb[FRA_SUPPRESS_IFGROUP])
 523                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 524         else
 525                 rule->suppress_ifgroup = -1;
 526
 527         if (tb[FRA_GOTO]) {
 528                 if (rule->action != FR_ACT_GOTO)
 529                         goto errout_free;
 530
 531                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 532                 /* Backward jumps are prohibited to avoid endless loops */
 533                 if (rule->target <= rule->pref)
 534                         goto errout_free;
 535
 536                 list_for_each_entry(r, &ops->rules_list, list) {
 537                         if (r->pref == rule->target) {
 538                                 RCU_INIT_POINTER(rule->ctarget, r);
 539                                 break;
 540                         }
 541                 }
 542
 543                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 544                         unresolved = 1;
 545         } else if (rule->action == FR_ACT_GOTO)
 546                 goto errout_free;
 547
 548         if (rule->l3mdev && rule->table)
 549                 goto errout_free;
 550
 551         if (tb[FRA_UID_RANGE]) {
 552                 if (current_user_ns() != net->user_ns) {
 553                         err = -EPERM;
 554                         goto errout_free;
 555                 }
 556
 557                 rule->uid_range = nla_get_kuid_range(tb);
 558
 559                 if (!uid_range_set(&rule->uid_range) ||
 560                     !uid_lte(rule->uid_range.start, rule->uid_range.end))
 561                         goto errout_free;
 562         } else {
 563                 rule->uid_range = fib_kuid_range_unset;
 564         }
 565
 566         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 567             rule_exists(ops, frh, tb, rule)) {
 568                 err = -EEXIST;
 569                 goto errout_free;
 570         }
 571
 572         err = ops->configure(rule, skb, frh, tb);
 573         if (err < 0)
 574                 goto errout_free;
 575
 576         list_for_each_entry(r, &ops->rules_list, list) {
 577                 if (r->pref > rule->pref)
 578                         break;
 579                 last = r;
 580         }
 581
 582         if (last)
 583                 list_add_rcu(&rule->list, &last->list);
 584         else
 585                 list_add_rcu(&rule->list, &ops->rules_list);
 586
 587         if (ops->unresolved_rules) {
 588                 /*
 589                  * There are unresolved goto rules in the list, check if
 590                  * any of them are pointing to this new rule.
 591                  */
 592                 list_for_each_entry(r, &ops->rules_list, list) {
 593                         if (r->action == FR_ACT_GOTO &&
 594                             r->target == rule->pref &&
 595                             rtnl_dereference(r->ctarget) == NULL) {
 596                                 rcu_assign_pointer(r->ctarget, rule);
 597                                 if (--ops->unresolved_rules == 0)
 598                                         break;
 599                         }
 600                 }
 601         }
 602
 603         if (rule->action == FR_ACT_GOTO)
 604                 ops->nr_goto_rules++;
 605
 606         if (unresolved)
 607                 ops->unresolved_rules++;
 608
 609         if (rule->tun_id)
 610                 ip_tunnel_need_metadata();
 611
 612         call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops);
 613         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 614         flush_route_cache(ops);
 615         rules_ops_put(ops);
 616         return 0;
 617
 618 errout_free:
 619         kfree(rule);
 620 errout:
 621         rules_ops_put(ops);
 622         return err;
 623 }
 624 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 625
 626 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 627                    struct netlink_ext_ack *extack)
 628 {
 629         struct net *net = sock_net(skb->sk);
 630         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 631         struct fib_rules_ops *ops = NULL;
 632         struct fib_rule *rule, *r;
 633         struct nlattr *tb[FRA_MAX+1];
 634         struct fib_kuid_range range;
 635         int err = -EINVAL;
 636
 637         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 638                 goto errout;
 639
 640         ops = lookup_rules_ops(net, frh->family);
 641         if (ops == NULL) {
 642                 err = -EAFNOSUPPORT;
 643                 goto errout;
 644         }
 645
 646         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 647         if (err < 0)
 648                 goto errout;
 649
 650         err = validate_rulemsg(frh, tb, ops);
 651         if (err < 0)
 652                 goto errout;
 653
 654         if (tb[FRA_UID_RANGE]) {
 655                 range = nla_get_kuid_range(tb);
 656                 if (!uid_range_set(&range)) {
 657                         err = -EINVAL;
 658                         goto errout;
 659                 }
 660         } else {
 661                 range = fib_kuid_range_unset;
 662         }
 663
 664         list_for_each_entry(rule, &ops->rules_list, list) {
 665                 if (frh->action && (frh->action != rule->action))
 666                         continue;
 667
 668                 if (frh_get_table(frh, tb) &&
 669                     (frh_get_table(frh, tb) != rule->table))
 670                         continue;
 671
 672                 if (tb[FRA_PRIORITY] &&
 673                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 674                         continue;
 675
 676                 if (tb[FRA_IIFNAME] &&
 677                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 678                         continue;
 679
 680                 if (tb[FRA_OIFNAME] &&
 681                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 682                         continue;
 683
 684                 if (tb[FRA_FWMARK] &&
 685                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 686                         continue;
 687
 688                 if (tb[FRA_FWMASK] &&
 689                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 690                         continue;
 691
 692                 if (tb[FRA_TUN_ID] &&
 693                     (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
 694                         continue;
 695
 696                 if (tb[FRA_L3MDEV] &&
 697                     (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
 698                         continue;
 699
 700                 if (uid_range_set(&range) &&
 701                     (!uid_eq(rule->uid_range.start, range.start) ||
 702                      !uid_eq(rule->uid_range.end, range.end)))
 703                         continue;
 704
 705                 if (!ops->compare(rule, frh, tb))
 706                         continue;
 707
 708                 if (rule->flags & FIB_RULE_PERMANENT) {
 709                         err = -EPERM;
 710                         goto errout;
 711                 }
 712
 713                 if (ops->delete) {
 714                         err = ops->delete(rule);
 715                         if (err)
 716                                 goto errout;
 717                 }
 718
 719                 if (rule->tun_id)
 720                         ip_tunnel_unneed_metadata();
 721
 722                 list_del_rcu(&rule->list);
 723
 724                 if (rule->action == FR_ACT_GOTO) {
 725                         ops->nr_goto_rules--;
 726                         if (rtnl_dereference(rule->ctarget) == NULL)
 727                                 ops->unresolved_rules--;
 728                 }
 729
 730                 /*
 731                  * Check if this rule is a target to any of them. If so,
 732                  * adjust to the next one with the same preference or
 733                  * disable them. As this operation is eventually very
 734                  * expensive, it is only performed if goto rules, except
 735                  * current if it is goto rule, have actually been added.
 736                  */
 737                 if (ops->nr_goto_rules > 0) {
 738                         struct fib_rule *n;
 739
 740                         n = list_next_entry(rule, list);
 741                         if (&n->list == &ops->rules_list || n->pref != rule->pref)
 742                                 n = NULL;
 743                         list_for_each_entry(r, &ops->rules_list, list) {
 744                                 if (rtnl_dereference(r->ctarget) != rule)
 745                                         continue;
 746                                 rcu_assign_pointer(r->ctarget, n);
 747                                 if (!n)
 748                                         ops->unresolved_rules++;
 749                         }
 750                 }
 751
 752                 call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops);
 753                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 754                                    NETLINK_CB(skb).portid);
 755                 fib_rule_put(rule);
 756                 flush_route_cache(ops);
 757                 rules_ops_put(ops);
 758                 return 0;
 759         }
 760
 761         err = -ENOENT;
 762 errout:
 763         rules_ops_put(ops);
 764         return err;
 765 }
 766 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 767
 768 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 769                                          struct fib_rule *rule)
 770 {
 771         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 772                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 773                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 774                          + nla_total_size(4) /* FRA_PRIORITY */
 775                          + nla_total_size(4) /* FRA_TABLE */
 776                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 777                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 778                          + nla_total_size(4) /* FRA_FWMARK */
 779                          + nla_total_size(4) /* FRA_FWMASK */
 780                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 781                          + nla_total_size(sizeof(struct fib_kuid_range));
 782
 783         if (ops->nlmsg_payload)
 784                 payload += ops->nlmsg_payload(rule);
 785
 786         return payload;
 787 }
 788
 789 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 790                             u32 pid, u32 seq, int type, int flags,
 791                             struct fib_rules_ops *ops)
 792 {
 793         struct nlmsghdr *nlh;
 794         struct fib_rule_hdr *frh;
 795
 796         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 797         if (nlh == NULL)
 798                 return -EMSGSIZE;
 799
 800         frh = nlmsg_data(nlh);
 801         frh->family = ops->family;
 802         frh->table = rule->table;
 803         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 804                 goto nla_put_failure;
 805         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 806                 goto nla_put_failure;
 807         frh->res1 = 0;
 808         frh->res2 = 0;
 809         frh->action = rule->action;
 810         frh->flags = rule->flags;
 811
 812         if (rule->action == FR_ACT_GOTO &&
 813             rcu_access_pointer(rule->ctarget) == NULL)
 814                 frh->flags |= FIB_RULE_UNRESOLVED;
 815
 816         if (rule->iifname[0]) {
 817                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 818                         goto nla_put_failure;
 819                 if (rule->iifindex == -1)
 820                         frh->flags |= FIB_RULE_IIF_DETACHED;
 821         }
 822
 823         if (rule->oifname[0]) {
 824                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 825                         goto nla_put_failure;
 826                 if (rule->oifindex == -1)
 827                         frh->flags |= FIB_RULE_OIF_DETACHED;
 828         }
 829
 830         if ((rule->pref &&
 831              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 832             (rule->mark &&
 833              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 834             ((rule->mark_mask || rule->mark) &&
 835              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 836             (rule->target &&
 837              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 838             (rule->tun_id &&
 839              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 840             (rule->l3mdev &&
 841              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
 842             (uid_range_set(&rule->uid_range) &&
 843              nla_put_uid_range(skb, &rule->uid_range)))
 844                 goto nla_put_failure;
 845
 846         if (rule->suppress_ifgroup != -1) {
 847                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 848                         goto nla_put_failure;
 849         }
 850
 851         if (ops->fill(rule, skb, frh) < 0)
 852                 goto nla_put_failure;
 853
 854         nlmsg_end(skb, nlh);
 855         return 0;
 856
 857 nla_put_failure:
 858         nlmsg_cancel(skb, nlh);
 859         return -EMSGSIZE;
 860 }
 861
 862 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 863                       struct fib_rules_ops *ops)
 864 {
 865         int idx = 0;
 866         struct fib_rule *rule;
 867         int err = 0;
 868
 869         rcu_read_lock();
 870         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 871                 if (idx < cb->args[1])
 872                         goto skip;
 873
 874                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 875                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
 876                                        NLM_F_MULTI, ops);
 877                 if (err)
 878                         break;
 879 skip:
 880                 idx++;
 881         }
 882         rcu_read_unlock();
 883         cb->args[1] = idx;
 884         rules_ops_put(ops);
 885
 886         return err;
 887 }
 888
 889 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 890 {
 891         struct net *net = sock_net(skb->sk);
 892         struct fib_rules_ops *ops;
 893         int idx = 0, family;
 894
 895         family = rtnl_msg_family(cb->nlh);
 896         if (family != AF_UNSPEC) {
 897                 /* Protocol specific dump request */
 898                 ops = lookup_rules_ops(net, family);
 899                 if (ops == NULL)
 900                         return -EAFNOSUPPORT;
 901
 902                 dump_rules(skb, cb, ops);
 903
 904                 return skb->len;
 905         }
 906
 907         rcu_read_lock();
 908         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 909                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 910                         goto skip;
 911
 912                 if (dump_rules(skb, cb, ops) < 0)
 913                         break;
 914
 915                 cb->args[1] = 0;
 916 skip:
 917                 idx++;
 918         }
 919         rcu_read_unlock();
 920         cb->args[0] = idx;
 921
 922         return skb->len;
 923 }
 924
 925 static void notify_rule_change(int event, struct fib_rule *rule,
 926                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 927                                u32 pid)
 928 {
 929         struct net *net;
 930         struct sk_buff *skb;
 931         int err = -ENOBUFS;
 932
 933         net = ops->fro_net;
 934         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 935         if (skb == NULL)
 936                 goto errout;
 937
 938         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 939         if (err < 0) {
 940                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 941                 WARN_ON(err == -EMSGSIZE);
 942                 kfree_skb(skb);
 943                 goto errout;
 944         }
 945
 946         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 947         return;
 948 errout:
 949         if (err < 0)
 950                 rtnl_set_sk_err(net, ops->nlgroup, err);
 951 }
 952
 953 static void attach_rules(struct list_head *rules, struct net_device *dev)
 954 {
 955         struct fib_rule *rule;
 956
 957         list_for_each_entry(rule, rules, list) {
 958                 if (rule->iifindex == -1 &&
 959                     strcmp(dev->name, rule->iifname) == 0)
 960                         rule->iifindex = dev->ifindex;
 961                 if (rule->oifindex == -1 &&
 962                     strcmp(dev->name, rule->oifname) == 0)
 963                         rule->oifindex = dev->ifindex;
 964         }
 965 }
 966
 967 static void detach_rules(struct list_head *rules, struct net_device *dev)
 968 {
 969         struct fib_rule *rule;
 970
 971         list_for_each_entry(rule, rules, list) {
 972                 if (rule->iifindex == dev->ifindex)
 973                         rule->iifindex = -1;
 974                 if (rule->oifindex == dev->ifindex)
 975                         rule->oifindex = -1;
 976         }
 977 }
 978
 979
 980 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 981                            void *ptr)
 982 {
 983         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 984         struct net *net = dev_net(dev);
 985         struct fib_rules_ops *ops;
 986
 987         ASSERT_RTNL();
 988
 989         switch (event) {
 990         case NETDEV_REGISTER:
 991                 list_for_each_entry(ops, &net->rules_ops, list)
 992                         attach_rules(&ops->rules_list, dev);
 993                 break;
 994
 995         case NETDEV_CHANGENAME:
 996                 list_for_each_entry(ops, &net->rules_ops, list) {
 997                         detach_rules(&ops->rules_list, dev);
 998                         attach_rules(&ops->rules_list, dev);
 999                 }
1000                 break;
1001
1002         case NETDEV_UNREGISTER:
1003                 list_for_each_entry(ops, &net->rules_ops, list)
1004                         detach_rules(&ops->rules_list, dev);
1005                 break;
1006         }
1007
1008         return NOTIFY_DONE;
1009 }
1010
1011 static struct notifier_block fib_rules_notifier = {
1012         .notifier_call = fib_rules_event,
1013 };
1014
1015 static int __net_init fib_rules_net_init(struct net *net)
1016 {
1017         INIT_LIST_HEAD(&net->rules_ops);
1018         spin_lock_init(&net->rules_mod_lock);
1019         return 0;
1020 }
1021
1022 static struct pernet_operations fib_rules_net_ops = {
1023         .init = fib_rules_net_init,
1024 };
1025
1026 static int __init fib_rules_init(void)
1027 {
1028         int err;
1029         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1030         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1031         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1032
1033         err = register_pernet_subsys(&fib_rules_net_ops);
1034         if (err < 0)
1035                 goto fail;
1036
1037         err = register_netdevice_notifier(&fib_rules_notifier);
1038         if (err < 0)
1039                 goto fail_unregister;
1040
1041         return 0;
1042
1043 fail_unregister:
1044         unregister_pernet_subsys(&fib_rules_net_ops);
1045 fail:
1046         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1047         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1048         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1049         return err;
1050 }
1051
1052 subsys_initcall(fib_rules_init);