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 <[email protected]>
   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                                    struct netlink_ext_ack *extack)
 319 {
 320         struct fib_rule_notifier_info info = {
 321                 .info.family = ops->family,
 322                 .info.extack = extack,
 323                 .rule = rule,
 324         };
 325
 326         ops->fib_rules_seq++;
 327         return call_fib_notifiers(net, event_type, &info.info);
 328 }
 329
 330 /* Called with rcu_read_lock() */
 331 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
 332 {
 333         struct fib_rules_ops *ops;
 334         struct fib_rule *rule;
 335
 336         ops = lookup_rules_ops(net, family);
 337         if (!ops)
 338                 return -EAFNOSUPPORT;
 339         list_for_each_entry_rcu(rule, &ops->rules_list, list)
 340                 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
 341                                        family);
 342         rules_ops_put(ops);
 343
 344         return 0;
 345 }
 346 EXPORT_SYMBOL_GPL(fib_rules_dump);
 347
 348 unsigned int fib_rules_seq_read(struct net *net, int family)
 349 {
 350         unsigned int fib_rules_seq;
 351         struct fib_rules_ops *ops;
 352
 353         ASSERT_RTNL();
 354
 355         ops = lookup_rules_ops(net, family);
 356         if (!ops)
 357                 return 0;
 358         fib_rules_seq = ops->fib_rules_seq;
 359         rules_ops_put(ops);
 360
 361         return fib_rules_seq;
 362 }
 363 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 364
 365 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 366                             struct fib_rules_ops *ops)
 367 {
 368         int err = -EINVAL;
 369
 370         if (frh->src_len)
 371                 if (tb[FRA_SRC] == NULL ||
 372                     frh->src_len > (ops->addr_size * 8) ||
 373                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 374                         goto errout;
 375
 376         if (frh->dst_len)
 377                 if (tb[FRA_DST] == NULL ||
 378                     frh->dst_len > (ops->addr_size * 8) ||
 379                     nla_len(tb[FRA_DST]) != ops->addr_size)
 380                         goto errout;
 381
 382         err = 0;
 383 errout:
 384         return err;
 385 }
 386
 387 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 388                        struct nlattr **tb, struct fib_rule *rule)
 389 {
 390         struct fib_rule *r;
 391
 392         list_for_each_entry(r, &ops->rules_list, list) {
 393                 if (r->action != rule->action)
 394                         continue;
 395
 396                 if (r->table != rule->table)
 397                         continue;
 398
 399                 if (r->pref != rule->pref)
 400                         continue;
 401
 402                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 403                         continue;
 404
 405                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 406                         continue;
 407
 408                 if (r->mark != rule->mark)
 409                         continue;
 410
 411                 if (r->mark_mask != rule->mark_mask)
 412                         continue;
 413
 414                 if (r->tun_id != rule->tun_id)
 415                         continue;
 416
 417                 if (r->fr_net != rule->fr_net)
 418                         continue;
 419
 420                 if (r->l3mdev != rule->l3mdev)
 421                         continue;
 422
 423                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 424                     !uid_eq(r->uid_range.end, rule->uid_range.end))
 425                         continue;
 426
 427                 if (!ops->compare(r, frh, tb))
 428                         continue;
 429                 return 1;
 430         }
 431         return 0;
 432 }
 433
 434 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 435                    struct netlink_ext_ack *extack)
 436 {
 437         struct net *net = sock_net(skb->sk);
 438         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 439         struct fib_rules_ops *ops = NULL;
 440         struct fib_rule *rule, *r, *last = NULL;
 441         struct nlattr *tb[FRA_MAX+1];
 442         int err = -EINVAL, unresolved = 0;
 443
 444         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 445                 goto errout;
 446
 447         ops = lookup_rules_ops(net, frh->family);
 448         if (ops == NULL) {
 449                 err = -EAFNOSUPPORT;
 450                 goto errout;
 451         }
 452
 453         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 454         if (err < 0)
 455                 goto errout;
 456
 457         err = validate_rulemsg(frh, tb, ops);
 458         if (err < 0)
 459                 goto errout;
 460
 461         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 462         if (rule == NULL) {
 463                 err = -ENOMEM;
 464                 goto errout;
 465         }
 466         refcount_set(&rule->refcnt, 1);
 467         rule->fr_net = net;
 468
 469         rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 470                                       : fib_default_rule_pref(ops);
 471
 472         if (tb[FRA_IIFNAME]) {
 473                 struct net_device *dev;
 474
 475                 rule->iifindex = -1;
 476                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 477                 dev = __dev_get_by_name(net, rule->iifname);
 478                 if (dev)
 479                         rule->iifindex = dev->ifindex;
 480         }
 481
 482         if (tb[FRA_OIFNAME]) {
 483                 struct net_device *dev;
 484
 485                 rule->oifindex = -1;
 486                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 487                 dev = __dev_get_by_name(net, rule->oifname);
 488                 if (dev)
 489                         rule->oifindex = dev->ifindex;
 490         }
 491
 492         if (tb[FRA_FWMARK]) {
 493                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 494                 if (rule->mark)
 495                         /* compatibility: if the mark value is non-zero all bits
 496                          * are compared unless a mask is explicitly specified.
 497                          */
 498                         rule->mark_mask = 0xFFFFFFFF;
 499         }
 500
 501         if (tb[FRA_FWMASK])
 502                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 503
 504         if (tb[FRA_TUN_ID])
 505                 rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 506
 507         err = -EINVAL;
 508         if (tb[FRA_L3MDEV]) {
 509 #ifdef CONFIG_NET_L3_MASTER_DEV
 510                 rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
 511                 if (rule->l3mdev != 1)
 512 #endif
 513                         goto errout_free;
 514         }
 515
 516         rule->action = frh->action;
 517         rule->flags = frh->flags;
 518         rule->table = frh_get_table(frh, tb);
 519         if (tb[FRA_SUPPRESS_PREFIXLEN])
 520                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 521         else
 522                 rule->suppress_prefixlen = -1;
 523
 524         if (tb[FRA_SUPPRESS_IFGROUP])
 525                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 526         else
 527                 rule->suppress_ifgroup = -1;
 528
 529         if (tb[FRA_GOTO]) {
 530                 if (rule->action != FR_ACT_GOTO)
 531                         goto errout_free;
 532
 533                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 534                 /* Backward jumps are prohibited to avoid endless loops */
 535                 if (rule->target <= rule->pref)
 536                         goto errout_free;
 537
 538                 list_for_each_entry(r, &ops->rules_list, list) {
 539                         if (r->pref == rule->target) {
 540                                 RCU_INIT_POINTER(rule->ctarget, r);
 541                                 break;
 542                         }
 543                 }
 544
 545                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 546                         unresolved = 1;
 547         } else if (rule->action == FR_ACT_GOTO)
 548                 goto errout_free;
 549
 550         if (rule->l3mdev && rule->table)
 551                 goto errout_free;
 552
 553         if (tb[FRA_UID_RANGE]) {
 554                 if (current_user_ns() != net->user_ns) {
 555                         err = -EPERM;
 556                         goto errout_free;
 557                 }
 558
 559                 rule->uid_range = nla_get_kuid_range(tb);
 560
 561                 if (!uid_range_set(&rule->uid_range) ||
 562                     !uid_lte(rule->uid_range.start, rule->uid_range.end))
 563                         goto errout_free;
 564         } else {
 565                 rule->uid_range = fib_kuid_range_unset;
 566         }
 567
 568         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 569             rule_exists(ops, frh, tb, rule)) {
 570                 err = -EEXIST;
 571                 goto errout_free;
 572         }
 573
 574         err = ops->configure(rule, skb, frh, tb);
 575         if (err < 0)
 576                 goto errout_free;
 577
 578         list_for_each_entry(r, &ops->rules_list, list) {
 579                 if (r->pref > rule->pref)
 580                         break;
 581                 last = r;
 582         }
 583
 584         if (last)
 585                 list_add_rcu(&rule->list, &last->list);
 586         else
 587                 list_add_rcu(&rule->list, &ops->rules_list);
 588
 589         if (ops->unresolved_rules) {
 590                 /*
 591                  * There are unresolved goto rules in the list, check if
 592                  * any of them are pointing to this new rule.
 593                  */
 594                 list_for_each_entry(r, &ops->rules_list, list) {
 595                         if (r->action == FR_ACT_GOTO &&
 596                             r->target == rule->pref &&
 597                             rtnl_dereference(r->ctarget) == NULL) {
 598                                 rcu_assign_pointer(r->ctarget, rule);
 599                                 if (--ops->unresolved_rules == 0)
 600                                         break;
 601                         }
 602                 }
 603         }
 604
 605         if (rule->action == FR_ACT_GOTO)
 606                 ops->nr_goto_rules++;
 607
 608         if (unresolved)
 609                 ops->unresolved_rules++;
 610
 611         if (rule->tun_id)
 612                 ip_tunnel_need_metadata();
 613
 614         call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops, extack);
 615         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 616         flush_route_cache(ops);
 617         rules_ops_put(ops);
 618         return 0;
 619
 620 errout_free:
 621         kfree(rule);
 622 errout:
 623         rules_ops_put(ops);
 624         return err;
 625 }
 626 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 627
 628 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 629                    struct netlink_ext_ack *extack)
 630 {
 631         struct net *net = sock_net(skb->sk);
 632         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 633         struct fib_rules_ops *ops = NULL;
 634         struct fib_rule *rule, *r;
 635         struct nlattr *tb[FRA_MAX+1];
 636         struct fib_kuid_range range;
 637         int err = -EINVAL;
 638
 639         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 640                 goto errout;
 641
 642         ops = lookup_rules_ops(net, frh->family);
 643         if (ops == NULL) {
 644                 err = -EAFNOSUPPORT;
 645                 goto errout;
 646         }
 647
 648         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 649         if (err < 0)
 650                 goto errout;
 651
 652         err = validate_rulemsg(frh, tb, ops);
 653         if (err < 0)
 654                 goto errout;
 655
 656         if (tb[FRA_UID_RANGE]) {
 657                 range = nla_get_kuid_range(tb);
 658                 if (!uid_range_set(&range)) {
 659                         err = -EINVAL;
 660                         goto errout;
 661                 }
 662         } else {
 663                 range = fib_kuid_range_unset;
 664         }
 665
 666         list_for_each_entry(rule, &ops->rules_list, list) {
 667                 if (frh->action && (frh->action != rule->action))
 668                         continue;
 669
 670                 if (frh_get_table(frh, tb) &&
 671                     (frh_get_table(frh, tb) != rule->table))
 672                         continue;
 673
 674                 if (tb[FRA_PRIORITY] &&
 675                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 676                         continue;
 677
 678                 if (tb[FRA_IIFNAME] &&
 679                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 680                         continue;
 681
 682                 if (tb[FRA_OIFNAME] &&
 683                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 684                         continue;
 685
 686                 if (tb[FRA_FWMARK] &&
 687                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 688                         continue;
 689
 690                 if (tb[FRA_FWMASK] &&
 691                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 692                         continue;
 693
 694                 if (tb[FRA_TUN_ID] &&
 695                     (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
 696                         continue;
 697
 698                 if (tb[FRA_L3MDEV] &&
 699                     (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
 700                         continue;
 701
 702                 if (uid_range_set(&range) &&
 703                     (!uid_eq(rule->uid_range.start, range.start) ||
 704                      !uid_eq(rule->uid_range.end, range.end)))
 705                         continue;
 706
 707                 if (!ops->compare(rule, frh, tb))
 708                         continue;
 709
 710                 if (rule->flags & FIB_RULE_PERMANENT) {
 711                         err = -EPERM;
 712                         goto errout;
 713                 }
 714
 715                 if (ops->delete) {
 716                         err = ops->delete(rule);
 717                         if (err)
 718                                 goto errout;
 719                 }
 720
 721                 if (rule->tun_id)
 722                         ip_tunnel_unneed_metadata();
 723
 724                 list_del_rcu(&rule->list);
 725
 726                 if (rule->action == FR_ACT_GOTO) {
 727                         ops->nr_goto_rules--;
 728                         if (rtnl_dereference(rule->ctarget) == NULL)
 729                                 ops->unresolved_rules--;
 730                 }
 731
 732                 /*
 733                  * Check if this rule is a target to any of them. If so,
 734                  * adjust to the next one with the same preference or
 735                  * disable them. As this operation is eventually very
 736                  * expensive, it is only performed if goto rules, except
 737                  * current if it is goto rule, have actually been added.
 738                  */
 739                 if (ops->nr_goto_rules > 0) {
 740                         struct fib_rule *n;
 741
 742                         n = list_next_entry(rule, list);
 743                         if (&n->list == &ops->rules_list || n->pref != rule->pref)
 744                                 n = NULL;
 745                         list_for_each_entry(r, &ops->rules_list, list) {
 746                                 if (rtnl_dereference(r->ctarget) != rule)
 747                                         continue;
 748                                 rcu_assign_pointer(r->ctarget, n);
 749                                 if (!n)
 750                                         ops->unresolved_rules++;
 751                         }
 752                 }
 753
 754                 call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
 755                                         NULL);
 756                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 757                                    NETLINK_CB(skb).portid);
 758                 fib_rule_put(rule);
 759                 flush_route_cache(ops);
 760                 rules_ops_put(ops);
 761                 return 0;
 762         }
 763
 764         err = -ENOENT;
 765 errout:
 766         rules_ops_put(ops);
 767         return err;
 768 }
 769 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 770
 771 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 772                                          struct fib_rule *rule)
 773 {
 774         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 775                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 776                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 777                          + nla_total_size(4) /* FRA_PRIORITY */
 778                          + nla_total_size(4) /* FRA_TABLE */
 779                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 780                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 781                          + nla_total_size(4) /* FRA_FWMARK */
 782                          + nla_total_size(4) /* FRA_FWMASK */
 783                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 784                          + nla_total_size(sizeof(struct fib_kuid_range));
 785
 786         if (ops->nlmsg_payload)
 787                 payload += ops->nlmsg_payload(rule);
 788
 789         return payload;
 790 }
 791
 792 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 793                             u32 pid, u32 seq, int type, int flags,
 794                             struct fib_rules_ops *ops)
 795 {
 796         struct nlmsghdr *nlh;
 797         struct fib_rule_hdr *frh;
 798
 799         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 800         if (nlh == NULL)
 801                 return -EMSGSIZE;
 802
 803         frh = nlmsg_data(nlh);
 804         frh->family = ops->family;
 805         frh->table = rule->table;
 806         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 807                 goto nla_put_failure;
 808         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 809                 goto nla_put_failure;
 810         frh->res1 = 0;
 811         frh->res2 = 0;
 812         frh->action = rule->action;
 813         frh->flags = rule->flags;
 814
 815         if (rule->action == FR_ACT_GOTO &&
 816             rcu_access_pointer(rule->ctarget) == NULL)
 817                 frh->flags |= FIB_RULE_UNRESOLVED;
 818
 819         if (rule->iifname[0]) {
 820                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 821                         goto nla_put_failure;
 822                 if (rule->iifindex == -1)
 823                         frh->flags |= FIB_RULE_IIF_DETACHED;
 824         }
 825
 826         if (rule->oifname[0]) {
 827                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 828                         goto nla_put_failure;
 829                 if (rule->oifindex == -1)
 830                         frh->flags |= FIB_RULE_OIF_DETACHED;
 831         }
 832
 833         if ((rule->pref &&
 834              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 835             (rule->mark &&
 836              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 837             ((rule->mark_mask || rule->mark) &&
 838              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 839             (rule->target &&
 840              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 841             (rule->tun_id &&
 842              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 843             (rule->l3mdev &&
 844              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
 845             (uid_range_set(&rule->uid_range) &&
 846              nla_put_uid_range(skb, &rule->uid_range)))
 847                 goto nla_put_failure;
 848
 849         if (rule->suppress_ifgroup != -1) {
 850                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 851                         goto nla_put_failure;
 852         }
 853
 854         if (ops->fill(rule, skb, frh) < 0)
 855                 goto nla_put_failure;
 856
 857         nlmsg_end(skb, nlh);
 858         return 0;
 859
 860 nla_put_failure:
 861         nlmsg_cancel(skb, nlh);
 862         return -EMSGSIZE;
 863 }
 864
 865 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 866                       struct fib_rules_ops *ops)
 867 {
 868         int idx = 0;
 869         struct fib_rule *rule;
 870         int err = 0;
 871
 872         rcu_read_lock();
 873         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 874                 if (idx < cb->args[1])
 875                         goto skip;
 876
 877                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 878                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
 879                                        NLM_F_MULTI, ops);
 880                 if (err)
 881                         break;
 882 skip:
 883                 idx++;
 884         }
 885         rcu_read_unlock();
 886         cb->args[1] = idx;
 887         rules_ops_put(ops);
 888
 889         return err;
 890 }
 891
 892 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 893 {
 894         struct net *net = sock_net(skb->sk);
 895         struct fib_rules_ops *ops;
 896         int idx = 0, family;
 897
 898         family = rtnl_msg_family(cb->nlh);
 899         if (family != AF_UNSPEC) {
 900                 /* Protocol specific dump request */
 901                 ops = lookup_rules_ops(net, family);
 902                 if (ops == NULL)
 903                         return -EAFNOSUPPORT;
 904
 905                 dump_rules(skb, cb, ops);
 906
 907                 return skb->len;
 908         }
 909
 910         rcu_read_lock();
 911         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 912                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 913                         goto skip;
 914
 915                 if (dump_rules(skb, cb, ops) < 0)
 916                         break;
 917
 918                 cb->args[1] = 0;
 919 skip:
 920                 idx++;
 921         }
 922         rcu_read_unlock();
 923         cb->args[0] = idx;
 924
 925         return skb->len;
 926 }
 927
 928 static void notify_rule_change(int event, struct fib_rule *rule,
 929                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 930                                u32 pid)
 931 {
 932         struct net *net;
 933         struct sk_buff *skb;
 934         int err = -ENOBUFS;
 935
 936         net = ops->fro_net;
 937         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 938         if (skb == NULL)
 939                 goto errout;
 940
 941         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 942         if (err < 0) {
 943                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 944                 WARN_ON(err == -EMSGSIZE);
 945                 kfree_skb(skb);
 946                 goto errout;
 947         }
 948
 949         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 950         return;
 951 errout:
 952         if (err < 0)
 953                 rtnl_set_sk_err(net, ops->nlgroup, err);
 954 }
 955
 956 static void attach_rules(struct list_head *rules, struct net_device *dev)
 957 {
 958         struct fib_rule *rule;
 959
 960         list_for_each_entry(rule, rules, list) {
 961                 if (rule->iifindex == -1 &&
 962                     strcmp(dev->name, rule->iifname) == 0)
 963                         rule->iifindex = dev->ifindex;
 964                 if (rule->oifindex == -1 &&
 965                     strcmp(dev->name, rule->oifname) == 0)
 966                         rule->oifindex = dev->ifindex;
 967         }
 968 }
 969
 970 static void detach_rules(struct list_head *rules, struct net_device *dev)
 971 {
 972         struct fib_rule *rule;
 973
 974         list_for_each_entry(rule, rules, list) {
 975                 if (rule->iifindex == dev->ifindex)
 976                         rule->iifindex = -1;
 977                 if (rule->oifindex == dev->ifindex)
 978                         rule->oifindex = -1;
 979         }
 980 }
 981
 982
 983 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 984                            void *ptr)
 985 {
 986         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 987         struct net *net = dev_net(dev);
 988         struct fib_rules_ops *ops;
 989
 990         ASSERT_RTNL();
 991
 992         switch (event) {
 993         case NETDEV_REGISTER:
 994                 list_for_each_entry(ops, &net->rules_ops, list)
 995                         attach_rules(&ops->rules_list, dev);
 996                 break;
 997
 998         case NETDEV_CHANGENAME:
 999                 list_for_each_entry(ops, &net->rules_ops, list) {
1000                         detach_rules(&ops->rules_list, dev);
1001                         attach_rules(&ops->rules_list, dev);
1002                 }
1003                 break;
1004
1005         case NETDEV_UNREGISTER:
1006                 list_for_each_entry(ops, &net->rules_ops, list)
1007                         detach_rules(&ops->rules_list, dev);
1008                 break;
1009         }
1010
1011         return NOTIFY_DONE;
1012 }
1013
1014 static struct notifier_block fib_rules_notifier = {
1015         .notifier_call = fib_rules_event,
1016 };
1017
1018 static int __net_init fib_rules_net_init(struct net *net)
1019 {
1020         INIT_LIST_HEAD(&net->rules_ops);
1021         spin_lock_init(&net->rules_mod_lock);
1022         return 0;
1023 }
1024
1025 static void __net_exit fib_rules_net_exit(struct net *net)
1026 {
1027         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1028 }
1029
1030 static struct pernet_operations fib_rules_net_ops = {
1031         .init = fib_rules_net_init,
1032         .exit = fib_rules_net_exit,
1033 };
1034
1035 static int __init fib_rules_init(void)
1036 {
1037         int err;
1038         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1039         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1040         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1041
1042         err = register_pernet_subsys(&fib_rules_net_ops);
1043         if (err < 0)
1044                 goto fail;
1045
1046         err = register_netdevice_notifier(&fib_rules_notifier);
1047         if (err < 0)
1048                 goto fail_unregister;
1049
1050         return 0;
1051
1052 fail_unregister:
1053         unregister_pernet_subsys(&fib_rules_net_ops);
1054 fail:
1055         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1056         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1057         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1058         return err;
1059 }
1060
1061 subsys_initcall(fib_rules_init);