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         if (fib_rule_port_range_set(&rule->sport_range))
  37                 return false;
  38         if (fib_rule_port_range_set(&rule->dport_range))
  39                 return false;
  40         return true;
  41 }
  42 EXPORT_SYMBOL_GPL(fib_rule_matchall);
  43
  44 int fib_default_rule_add(struct fib_rules_ops *ops,
  45                          u32 pref, u32 table, u32 flags)
  46 {
  47         struct fib_rule *r;
  48
  49         r = kzalloc(ops->rule_size, GFP_KERNEL);
  50         if (r == NULL)
  51                 return -ENOMEM;
  52
  53         refcount_set(&r->refcnt, 1);
  54         r->action = FR_ACT_TO_TBL;
  55         r->pref = pref;
  56         r->table = table;
  57         r->flags = flags;
  58         r->proto = RTPROT_KERNEL;
  59         r->fr_net = ops->fro_net;
  60         r->uid_range = fib_kuid_range_unset;
  61
  62         r->suppress_prefixlen = -1;
  63         r->suppress_ifgroup = -1;
  64
  65         /* The lock is not required here, the list in unreacheable
  66          * at the moment this function is called */
  67         list_add_tail(&r->list, &ops->rules_list);
  68         return 0;
  69 }
  70 EXPORT_SYMBOL(fib_default_rule_add);
  71
  72 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  73 {
  74         struct list_head *pos;
  75         struct fib_rule *rule;
  76
  77         if (!list_empty(&ops->rules_list)) {
  78                 pos = ops->rules_list.next;
  79                 if (pos->next != &ops->rules_list) {
  80                         rule = list_entry(pos->next, struct fib_rule, list);
  81                         if (rule->pref)
  82                                 return rule->pref - 1;
  83                 }
  84         }
  85
  86         return 0;
  87 }
  88
  89 static void notify_rule_change(int event, struct fib_rule *rule,
  90                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  91                                u32 pid);
  92
  93 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  94 {
  95         struct fib_rules_ops *ops;
  96
  97         rcu_read_lock();
  98         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  99                 if (ops->family == family) {
 100                         if (!try_module_get(ops->owner))
 101                                 ops = NULL;
 102                         rcu_read_unlock();
 103                         return ops;
 104                 }
 105         }
 106         rcu_read_unlock();
 107
 108         return NULL;
 109 }
 110
 111 static void rules_ops_put(struct fib_rules_ops *ops)
 112 {
 113         if (ops)
 114                 module_put(ops->owner);
 115 }
 116
 117 static void flush_route_cache(struct fib_rules_ops *ops)
 118 {
 119         if (ops->flush_cache)
 120                 ops->flush_cache(ops);
 121 }
 122
 123 static int __fib_rules_register(struct fib_rules_ops *ops)
 124 {
 125         int err = -EEXIST;
 126         struct fib_rules_ops *o;
 127         struct net *net;
 128
 129         net = ops->fro_net;
 130
 131         if (ops->rule_size < sizeof(struct fib_rule))
 132                 return -EINVAL;
 133
 134         if (ops->match == NULL || ops->configure == NULL ||
 135             ops->compare == NULL || ops->fill == NULL ||
 136             ops->action == NULL)
 137                 return -EINVAL;
 138
 139         spin_lock(&net->rules_mod_lock);
 140         list_for_each_entry(o, &net->rules_ops, list)
 141                 if (ops->family == o->family)
 142                         goto errout;
 143
 144         list_add_tail_rcu(&ops->list, &net->rules_ops);
 145         err = 0;
 146 errout:
 147         spin_unlock(&net->rules_mod_lock);
 148
 149         return err;
 150 }
 151
 152 struct fib_rules_ops *
 153 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 154 {
 155         struct fib_rules_ops *ops;
 156         int err;
 157
 158         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 159         if (ops == NULL)
 160                 return ERR_PTR(-ENOMEM);
 161
 162         INIT_LIST_HEAD(&ops->rules_list);
 163         ops->fro_net = net;
 164
 165         err = __fib_rules_register(ops);
 166         if (err) {
 167                 kfree(ops);
 168                 ops = ERR_PTR(err);
 169         }
 170
 171         return ops;
 172 }
 173 EXPORT_SYMBOL_GPL(fib_rules_register);
 174
 175 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 176 {
 177         struct fib_rule *rule, *tmp;
 178
 179         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 180                 list_del_rcu(&rule->list);
 181                 if (ops->delete)
 182                         ops->delete(rule);
 183                 fib_rule_put(rule);
 184         }
 185 }
 186
 187 void fib_rules_unregister(struct fib_rules_ops *ops)
 188 {
 189         struct net *net = ops->fro_net;
 190
 191         spin_lock(&net->rules_mod_lock);
 192         list_del_rcu(&ops->list);
 193         spin_unlock(&net->rules_mod_lock);
 194
 195         fib_rules_cleanup_ops(ops);
 196         kfree_rcu(ops, rcu);
 197 }
 198 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 199
 200 static int uid_range_set(struct fib_kuid_range *range)
 201 {
 202         return uid_valid(range->start) && uid_valid(range->end);
 203 }
 204
 205 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
 206 {
 207         struct fib_rule_uid_range *in;
 208         struct fib_kuid_range out;
 209
 210         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
 211
 212         out.start = make_kuid(current_user_ns(), in->start);
 213         out.end = make_kuid(current_user_ns(), in->end);
 214
 215         return out;
 216 }
 217
 218 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
 219 {
 220         struct fib_rule_uid_range out = {
 221                 from_kuid_munged(current_user_ns(), range->start),
 222                 from_kuid_munged(current_user_ns(), range->end)
 223         };
 224
 225         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
 226 }
 227
 228 static int nla_get_port_range(struct nlattr *pattr,
 229                               struct fib_rule_port_range *port_range)
 230 {
 231         const struct fib_rule_port_range *pr = nla_data(pattr);
 232
 233         if (!fib_rule_port_range_valid(pr))
 234                 return -EINVAL;
 235
 236         port_range->start = pr->start;
 237         port_range->end = pr->end;
 238
 239         return 0;
 240 }
 241
 242 static int nla_put_port_range(struct sk_buff *skb, int attrtype,
 243                               struct fib_rule_port_range *range)
 244 {
 245         return nla_put(skb, attrtype, sizeof(*range), range);
 246 }
 247
 248 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 249                           struct flowi *fl, int flags,
 250                           struct fib_lookup_arg *arg)
 251 {
 252         int ret = 0;
 253
 254         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 255                 goto out;
 256
 257         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 258                 goto out;
 259
 260         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 261                 goto out;
 262
 263         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
 264                 goto out;
 265
 266         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
 267                 goto out;
 268
 269         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
 270             uid_gt(fl->flowi_uid, rule->uid_range.end))
 271                 goto out;
 272
 273         ret = ops->match(rule, fl, flags);
 274 out:
 275         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 276 }
 277
 278 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 279                      int flags, struct fib_lookup_arg *arg)
 280 {
 281         struct fib_rule *rule;
 282         int err;
 283
 284         rcu_read_lock();
 285
 286         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 287 jumped:
 288                 if (!fib_rule_match(rule, ops, fl, flags, arg))
 289                         continue;
 290
 291                 if (rule->action == FR_ACT_GOTO) {
 292                         struct fib_rule *target;
 293
 294                         target = rcu_dereference(rule->ctarget);
 295                         if (target == NULL) {
 296                                 continue;
 297                         } else {
 298                                 rule = target;
 299                                 goto jumped;
 300                         }
 301                 } else if (rule->action == FR_ACT_NOP)
 302                         continue;
 303                 else
 304                         err = ops->action(rule, fl, flags, arg);
 305
 306                 if (!err && ops->suppress && ops->suppress(rule, arg))
 307                         continue;
 308
 309                 if (err != -EAGAIN) {
 310                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 311                             likely(refcount_inc_not_zero(&rule->refcnt))) {
 312                                 arg->rule = rule;
 313                                 goto out;
 314                         }
 315                         break;
 316                 }
 317         }
 318
 319         err = -ESRCH;
 320 out:
 321         rcu_read_unlock();
 322
 323         return err;
 324 }
 325 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 326
 327 static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
 328                                   enum fib_event_type event_type,
 329                                   struct fib_rule *rule, int family)
 330 {
 331         struct fib_rule_notifier_info info = {
 332                 .info.family = family,
 333                 .rule = rule,
 334         };
 335
 336         return call_fib_notifier(nb, net, event_type, &info.info);
 337 }
 338
 339 static int call_fib_rule_notifiers(struct net *net,
 340                                    enum fib_event_type event_type,
 341                                    struct fib_rule *rule,
 342                                    struct fib_rules_ops *ops,
 343                                    struct netlink_ext_ack *extack)
 344 {
 345         struct fib_rule_notifier_info info = {
 346                 .info.family = ops->family,
 347                 .info.extack = extack,
 348                 .rule = rule,
 349         };
 350
 351         ops->fib_rules_seq++;
 352         return call_fib_notifiers(net, event_type, &info.info);
 353 }
 354
 355 /* Called with rcu_read_lock() */
 356 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
 357 {
 358         struct fib_rules_ops *ops;
 359         struct fib_rule *rule;
 360
 361         ops = lookup_rules_ops(net, family);
 362         if (!ops)
 363                 return -EAFNOSUPPORT;
 364         list_for_each_entry_rcu(rule, &ops->rules_list, list)
 365                 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
 366                                        family);
 367         rules_ops_put(ops);
 368
 369         return 0;
 370 }
 371 EXPORT_SYMBOL_GPL(fib_rules_dump);
 372
 373 unsigned int fib_rules_seq_read(struct net *net, int family)
 374 {
 375         unsigned int fib_rules_seq;
 376         struct fib_rules_ops *ops;
 377
 378         ASSERT_RTNL();
 379
 380         ops = lookup_rules_ops(net, family);
 381         if (!ops)
 382                 return 0;
 383         fib_rules_seq = ops->fib_rules_seq;
 384         rules_ops_put(ops);
 385
 386         return fib_rules_seq;
 387 }
 388 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 389
 390 static struct fib_rule *rule_find(struct fib_rules_ops *ops,
 391                                   struct fib_rule_hdr *frh,
 392                                   struct nlattr **tb,
 393                                   struct fib_rule *rule,
 394                                   bool user_priority)
 395 {
 396         struct fib_rule *r;
 397
 398         list_for_each_entry(r, &ops->rules_list, list) {
 399                 if (rule->action && r->action != rule->action)
 400                         continue;
 401
 402                 if (rule->table && r->table != rule->table)
 403                         continue;
 404
 405                 if (user_priority && r->pref != rule->pref)
 406                         continue;
 407
 408                 if (rule->iifname[0] &&
 409                     memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 410                         continue;
 411
 412                 if (rule->oifname[0] &&
 413                     memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 414                         continue;
 415
 416                 if (rule->mark && r->mark != rule->mark)
 417                         continue;
 418
 419                 if (rule->mark_mask && r->mark_mask != rule->mark_mask)
 420                         continue;
 421
 422                 if (rule->tun_id && r->tun_id != rule->tun_id)
 423                         continue;
 424
 425                 if (r->fr_net != rule->fr_net)
 426                         continue;
 427
 428                 if (rule->l3mdev && r->l3mdev != rule->l3mdev)
 429                         continue;
 430
 431                 if (uid_range_set(&rule->uid_range) &&
 432                     (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 433                     !uid_eq(r->uid_range.end, rule->uid_range.end)))
 434                         continue;
 435
 436                 if (rule->ip_proto && r->ip_proto != rule->ip_proto)
 437                         continue;
 438
 439                 if (fib_rule_port_range_set(&rule->sport_range) &&
 440                     !fib_rule_port_range_compare(&r->sport_range,
 441                                                  &rule->sport_range))
 442                         continue;
 443
 444                 if (fib_rule_port_range_set(&rule->dport_range) &&
 445                     !fib_rule_port_range_compare(&r->dport_range,
 446                                                  &rule->dport_range))
 447                         continue;
 448
 449                 if (!ops->compare(r, frh, tb))
 450                         continue;
 451                 return r;
 452         }
 453
 454         return NULL;
 455 }
 456
 457 #ifdef CONFIG_NET_L3_MASTER_DEV
 458 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
 459                               struct netlink_ext_ack *extack)
 460 {
 461         nlrule->l3mdev = nla_get_u8(nla);
 462         if (nlrule->l3mdev != 1) {
 463                 NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
 464                 return -1;
 465         }
 466
 467         return 0;
 468 }
 469 #else
 470 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
 471                               struct netlink_ext_ack *extack)
 472 {
 473         NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
 474         return -1;
 475 }
 476 #endif
 477
 478 static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
 479                        struct netlink_ext_ack *extack,
 480                        struct fib_rules_ops *ops,
 481                        struct nlattr *tb[],
 482                        struct fib_rule **rule,
 483                        bool *user_priority)
 484 {
 485         struct net *net = sock_net(skb->sk);
 486         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 487         struct fib_rule *nlrule = NULL;
 488         int err = -EINVAL;
 489
 490         if (frh->src_len)
 491                 if (!tb[FRA_SRC] ||
 492                     frh->src_len > (ops->addr_size * 8) ||
 493                     nla_len(tb[FRA_SRC]) != ops->addr_size) {
 494                         NL_SET_ERR_MSG(extack, "Invalid source address");
 495                         goto errout;
 496         }
 497
 498         if (frh->dst_len)
 499                 if (!tb[FRA_DST] ||
 500                     frh->dst_len > (ops->addr_size * 8) ||
 501                     nla_len(tb[FRA_DST]) != ops->addr_size) {
 502                         NL_SET_ERR_MSG(extack, "Invalid dst address");
 503                         goto errout;
 504         }
 505
 506         nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
 507         if (!nlrule) {
 508                 err = -ENOMEM;
 509                 goto errout;
 510         }
 511         refcount_set(&nlrule->refcnt, 1);
 512         nlrule->fr_net = net;
 513
 514         if (tb[FRA_PRIORITY]) {
 515                 nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 516                 *user_priority = true;
 517         } else {
 518                 nlrule->pref = fib_default_rule_pref(ops);
 519         }
 520
 521         nlrule->proto = tb[FRA_PROTOCOL] ?
 522                 nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
 523
 524         if (tb[FRA_IIFNAME]) {
 525                 struct net_device *dev;
 526
 527                 nlrule->iifindex = -1;
 528                 nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 529                 dev = __dev_get_by_name(net, nlrule->iifname);
 530                 if (dev)
 531                         nlrule->iifindex = dev->ifindex;
 532         }
 533
 534         if (tb[FRA_OIFNAME]) {
 535                 struct net_device *dev;
 536
 537                 nlrule->oifindex = -1;
 538                 nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 539                 dev = __dev_get_by_name(net, nlrule->oifname);
 540                 if (dev)
 541                         nlrule->oifindex = dev->ifindex;
 542         }
 543
 544         if (tb[FRA_FWMARK]) {
 545                 nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
 546                 if (nlrule->mark)
 547                         /* compatibility: if the mark value is non-zero all bits
 548                          * are compared unless a mask is explicitly specified.
 549                          */
 550                         nlrule->mark_mask = 0xFFFFFFFF;
 551         }
 552
 553         if (tb[FRA_FWMASK])
 554                 nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 555
 556         if (tb[FRA_TUN_ID])
 557                 nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 558
 559         err = -EINVAL;
 560         if (tb[FRA_L3MDEV] &&
 561             fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
 562                 goto errout_free;
 563
 564         nlrule->action = frh->action;
 565         nlrule->flags = frh->flags;
 566         nlrule->table = frh_get_table(frh, tb);
 567         if (tb[FRA_SUPPRESS_PREFIXLEN])
 568                 nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 569         else
 570                 nlrule->suppress_prefixlen = -1;
 571
 572         if (tb[FRA_SUPPRESS_IFGROUP])
 573                 nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 574         else
 575                 nlrule->suppress_ifgroup = -1;
 576
 577         if (tb[FRA_GOTO]) {
 578                 if (nlrule->action != FR_ACT_GOTO) {
 579                         NL_SET_ERR_MSG(extack, "Unexpected goto");
 580                         goto errout_free;
 581                 }
 582
 583                 nlrule->target = nla_get_u32(tb[FRA_GOTO]);
 584                 /* Backward jumps are prohibited to avoid endless loops */
 585                 if (nlrule->target <= nlrule->pref) {
 586                         NL_SET_ERR_MSG(extack, "Backward goto not supported");
 587                         goto errout_free;
 588                 }
 589         } else if (nlrule->action == FR_ACT_GOTO) {
 590                 NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
 591                 goto errout_free;
 592         }
 593
 594         if (nlrule->l3mdev && nlrule->table) {
 595                 NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
 596                 goto errout_free;
 597         }
 598
 599         if (tb[FRA_UID_RANGE]) {
 600                 if (current_user_ns() != net->user_ns) {
 601                         err = -EPERM;
 602                         NL_SET_ERR_MSG(extack, "No permission to set uid");
 603                         goto errout_free;
 604                 }
 605
 606                 nlrule->uid_range = nla_get_kuid_range(tb);
 607
 608                 if (!uid_range_set(&nlrule->uid_range) ||
 609                     !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
 610                         NL_SET_ERR_MSG(extack, "Invalid uid range");
 611                         goto errout_free;
 612                 }
 613         } else {
 614                 nlrule->uid_range = fib_kuid_range_unset;
 615         }
 616
 617         if (tb[FRA_IP_PROTO])
 618                 nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
 619
 620         if (tb[FRA_SPORT_RANGE]) {
 621                 err = nla_get_port_range(tb[FRA_SPORT_RANGE],
 622                                          &nlrule->sport_range);
 623                 if (err) {
 624                         NL_SET_ERR_MSG(extack, "Invalid sport range");
 625                         goto errout_free;
 626                 }
 627         }
 628
 629         if (tb[FRA_DPORT_RANGE]) {
 630                 err = nla_get_port_range(tb[FRA_DPORT_RANGE],
 631                                          &nlrule->dport_range);
 632                 if (err) {
 633                         NL_SET_ERR_MSG(extack, "Invalid dport range");
 634                         goto errout_free;
 635                 }
 636         }
 637
 638         *rule = nlrule;
 639
 640         return 0;
 641
 642 errout_free:
 643         kfree(nlrule);
 644 errout:
 645         return err;
 646 }
 647
 648 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 649                    struct netlink_ext_ack *extack)
 650 {
 651         struct net *net = sock_net(skb->sk);
 652         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 653         struct fib_rules_ops *ops = NULL;
 654         struct fib_rule *rule = NULL, *r, *last = NULL;
 655         struct nlattr *tb[FRA_MAX + 1];
 656         int err = -EINVAL, unresolved = 0;
 657         bool user_priority = false;
 658
 659         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
 660                 NL_SET_ERR_MSG(extack, "Invalid msg length");
 661                 goto errout;
 662         }
 663
 664         ops = lookup_rules_ops(net, frh->family);
 665         if (!ops) {
 666                 err = -EAFNOSUPPORT;
 667                 NL_SET_ERR_MSG(extack, "Rule family not supported");
 668                 goto errout;
 669         }
 670
 671         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 672         if (err < 0) {
 673                 NL_SET_ERR_MSG(extack, "Error parsing msg");
 674                 goto errout;
 675         }
 676
 677         err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
 678         if (err)
 679                 goto errout;
 680
 681         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 682             rule_find(ops, frh, tb, rule, user_priority)) {
 683                 err = -EEXIST;
 684                 goto errout_free;
 685         }
 686
 687         err = ops->configure(rule, skb, frh, tb, extack);
 688         if (err < 0)
 689                 goto errout_free;
 690
 691         err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
 692                                       extack);
 693         if (err < 0)
 694                 goto errout_free;
 695
 696         list_for_each_entry(r, &ops->rules_list, list) {
 697                 if (r->pref == rule->target) {
 698                         RCU_INIT_POINTER(rule->ctarget, r);
 699                         break;
 700                 }
 701         }
 702
 703         if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 704                 unresolved = 1;
 705
 706         list_for_each_entry(r, &ops->rules_list, list) {
 707                 if (r->pref > rule->pref)
 708                         break;
 709                 last = r;
 710         }
 711
 712         if (last)
 713                 list_add_rcu(&rule->list, &last->list);
 714         else
 715                 list_add_rcu(&rule->list, &ops->rules_list);
 716
 717         if (ops->unresolved_rules) {
 718                 /*
 719                  * There are unresolved goto rules in the list, check if
 720                  * any of them are pointing to this new rule.
 721                  */
 722                 list_for_each_entry(r, &ops->rules_list, list) {
 723                         if (r->action == FR_ACT_GOTO &&
 724                             r->target == rule->pref &&
 725                             rtnl_dereference(r->ctarget) == NULL) {
 726                                 rcu_assign_pointer(r->ctarget, rule);
 727                                 if (--ops->unresolved_rules == 0)
 728                                         break;
 729                         }
 730                 }
 731         }
 732
 733         if (rule->action == FR_ACT_GOTO)
 734                 ops->nr_goto_rules++;
 735
 736         if (unresolved)
 737                 ops->unresolved_rules++;
 738
 739         if (rule->tun_id)
 740                 ip_tunnel_need_metadata();
 741
 742         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 743         flush_route_cache(ops);
 744         rules_ops_put(ops);
 745         return 0;
 746
 747 errout_free:
 748         kfree(rule);
 749 errout:
 750         rules_ops_put(ops);
 751         return err;
 752 }
 753 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 754
 755 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 756                    struct netlink_ext_ack *extack)
 757 {
 758         struct net *net = sock_net(skb->sk);
 759         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 760         struct fib_rules_ops *ops = NULL;
 761         struct fib_rule *rule = NULL, *r, *nlrule = NULL;
 762         struct nlattr *tb[FRA_MAX+1];
 763         int err = -EINVAL;
 764         bool user_priority = false;
 765
 766         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
 767                 NL_SET_ERR_MSG(extack, "Invalid msg length");
 768                 goto errout;
 769         }
 770
 771         ops = lookup_rules_ops(net, frh->family);
 772         if (ops == NULL) {
 773                 err = -EAFNOSUPPORT;
 774                 NL_SET_ERR_MSG(extack, "Rule family not supported");
 775                 goto errout;
 776         }
 777
 778         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 779         if (err < 0) {
 780                 NL_SET_ERR_MSG(extack, "Error parsing msg");
 781                 goto errout;
 782         }
 783
 784         err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
 785         if (err)
 786                 goto errout;
 787
 788         rule = rule_find(ops, frh, tb, nlrule, user_priority);
 789         if (!rule) {
 790                 err = -ENOENT;
 791                 goto errout;
 792         }
 793
 794         if (rule->flags & FIB_RULE_PERMANENT) {
 795                 err = -EPERM;
 796                 goto errout;
 797         }
 798
 799         if (ops->delete) {
 800                 err = ops->delete(rule);
 801                 if (err)
 802                         goto errout;
 803         }
 804
 805         if (rule->tun_id)
 806                 ip_tunnel_unneed_metadata();
 807
 808         list_del_rcu(&rule->list);
 809
 810         if (rule->action == FR_ACT_GOTO) {
 811                 ops->nr_goto_rules--;
 812                 if (rtnl_dereference(rule->ctarget) == NULL)
 813                         ops->unresolved_rules--;
 814         }
 815
 816         /*
 817          * Check if this rule is a target to any of them. If so,
 818          * adjust to the next one with the same preference or
 819          * disable them. As this operation is eventually very
 820          * expensive, it is only performed if goto rules, except
 821          * current if it is goto rule, have actually been added.
 822          */
 823         if (ops->nr_goto_rules > 0) {
 824                 struct fib_rule *n;
 825
 826                 n = list_next_entry(rule, list);
 827                 if (&n->list == &ops->rules_list || n->pref != rule->pref)
 828                         n = NULL;
 829                 list_for_each_entry(r, &ops->rules_list, list) {
 830                         if (rtnl_dereference(r->ctarget) != rule)
 831                                 continue;
 832                         rcu_assign_pointer(r->ctarget, n);
 833                         if (!n)
 834                                 ops->unresolved_rules++;
 835                 }
 836         }
 837
 838         call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
 839                                 NULL);
 840         notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 841                            NETLINK_CB(skb).portid);
 842         fib_rule_put(rule);
 843         flush_route_cache(ops);
 844         rules_ops_put(ops);
 845         kfree(nlrule);
 846         return 0;
 847
 848 errout:
 849         if (nlrule)
 850                 kfree(nlrule);
 851         rules_ops_put(ops);
 852         return err;
 853 }
 854 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 855
 856 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 857                                          struct fib_rule *rule)
 858 {
 859         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 860                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 861                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 862                          + nla_total_size(4) /* FRA_PRIORITY */
 863                          + nla_total_size(4) /* FRA_TABLE */
 864                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 865                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 866                          + nla_total_size(4) /* FRA_FWMARK */
 867                          + nla_total_size(4) /* FRA_FWMASK */
 868                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 869                          + nla_total_size(sizeof(struct fib_kuid_range))
 870                          + nla_total_size(1) /* FRA_PROTOCOL */
 871                          + nla_total_size(1) /* FRA_IP_PROTO */
 872                          + nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
 873                          + nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
 874
 875         if (ops->nlmsg_payload)
 876                 payload += ops->nlmsg_payload(rule);
 877
 878         return payload;
 879 }
 880
 881 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 882                             u32 pid, u32 seq, int type, int flags,
 883                             struct fib_rules_ops *ops)
 884 {
 885         struct nlmsghdr *nlh;
 886         struct fib_rule_hdr *frh;
 887
 888         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 889         if (nlh == NULL)
 890                 return -EMSGSIZE;
 891
 892         frh = nlmsg_data(nlh);
 893         frh->family = ops->family;
 894         frh->table = rule->table;
 895         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 896                 goto nla_put_failure;
 897         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 898                 goto nla_put_failure;
 899         frh->res1 = 0;
 900         frh->res2 = 0;
 901         frh->action = rule->action;
 902         frh->flags = rule->flags;
 903
 904         if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
 905                 goto nla_put_failure;
 906
 907         if (rule->action == FR_ACT_GOTO &&
 908             rcu_access_pointer(rule->ctarget) == NULL)
 909                 frh->flags |= FIB_RULE_UNRESOLVED;
 910
 911         if (rule->iifname[0]) {
 912                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 913                         goto nla_put_failure;
 914                 if (rule->iifindex == -1)
 915                         frh->flags |= FIB_RULE_IIF_DETACHED;
 916         }
 917
 918         if (rule->oifname[0]) {
 919                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 920                         goto nla_put_failure;
 921                 if (rule->oifindex == -1)
 922                         frh->flags |= FIB_RULE_OIF_DETACHED;
 923         }
 924
 925         if ((rule->pref &&
 926              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 927             (rule->mark &&
 928              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 929             ((rule->mark_mask || rule->mark) &&
 930              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 931             (rule->target &&
 932              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 933             (rule->tun_id &&
 934              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 935             (rule->l3mdev &&
 936              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
 937             (uid_range_set(&rule->uid_range) &&
 938              nla_put_uid_range(skb, &rule->uid_range)) ||
 939             (fib_rule_port_range_set(&rule->sport_range) &&
 940              nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
 941             (fib_rule_port_range_set(&rule->dport_range) &&
 942              nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
 943             (rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
 944                 goto nla_put_failure;
 945
 946         if (rule->suppress_ifgroup != -1) {
 947                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 948                         goto nla_put_failure;
 949         }
 950
 951         if (ops->fill(rule, skb, frh) < 0)
 952                 goto nla_put_failure;
 953
 954         nlmsg_end(skb, nlh);
 955         return 0;
 956
 957 nla_put_failure:
 958         nlmsg_cancel(skb, nlh);
 959         return -EMSGSIZE;
 960 }
 961
 962 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 963                       struct fib_rules_ops *ops)
 964 {
 965         int idx = 0;
 966         struct fib_rule *rule;
 967         int err = 0;
 968
 969         rcu_read_lock();
 970         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 971                 if (idx < cb->args[1])
 972                         goto skip;
 973
 974                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 975                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
 976                                        NLM_F_MULTI, ops);
 977                 if (err)
 978                         break;
 979 skip:
 980                 idx++;
 981         }
 982         rcu_read_unlock();
 983         cb->args[1] = idx;
 984         rules_ops_put(ops);
 985
 986         return err;
 987 }
 988
 989 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 990 {
 991         struct net *net = sock_net(skb->sk);
 992         struct fib_rules_ops *ops;
 993         int idx = 0, family;
 994
 995         family = rtnl_msg_family(cb->nlh);
 996         if (family != AF_UNSPEC) {
 997                 /* Protocol specific dump request */
 998                 ops = lookup_rules_ops(net, family);
 999                 if (ops == NULL)
1000                         return -EAFNOSUPPORT;
1001
1002                 dump_rules(skb, cb, ops);
1003
1004                 return skb->len;
1005         }
1006
1007         rcu_read_lock();
1008         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
1009                 if (idx < cb->args[0] || !try_module_get(ops->owner))
1010                         goto skip;
1011
1012                 if (dump_rules(skb, cb, ops) < 0)
1013                         break;
1014
1015                 cb->args[1] = 0;
1016 skip:
1017                 idx++;
1018         }
1019         rcu_read_unlock();
1020         cb->args[0] = idx;
1021
1022         return skb->len;
1023 }
1024
1025 static void notify_rule_change(int event, struct fib_rule *rule,
1026                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
1027                                u32 pid)
1028 {
1029         struct net *net;
1030         struct sk_buff *skb;
1031         int err = -ENOBUFS;
1032
1033         net = ops->fro_net;
1034         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
1035         if (skb == NULL)
1036                 goto errout;
1037
1038         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
1039         if (err < 0) {
1040                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
1041                 WARN_ON(err == -EMSGSIZE);
1042                 kfree_skb(skb);
1043                 goto errout;
1044         }
1045
1046         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
1047         return;
1048 errout:
1049         if (err < 0)
1050                 rtnl_set_sk_err(net, ops->nlgroup, err);
1051 }
1052
1053 static void attach_rules(struct list_head *rules, struct net_device *dev)
1054 {
1055         struct fib_rule *rule;
1056
1057         list_for_each_entry(rule, rules, list) {
1058                 if (rule->iifindex == -1 &&
1059                     strcmp(dev->name, rule->iifname) == 0)
1060                         rule->iifindex = dev->ifindex;
1061                 if (rule->oifindex == -1 &&
1062                     strcmp(dev->name, rule->oifname) == 0)
1063                         rule->oifindex = dev->ifindex;
1064         }
1065 }
1066
1067 static void detach_rules(struct list_head *rules, struct net_device *dev)
1068 {
1069         struct fib_rule *rule;
1070
1071         list_for_each_entry(rule, rules, list) {
1072                 if (rule->iifindex == dev->ifindex)
1073                         rule->iifindex = -1;
1074                 if (rule->oifindex == dev->ifindex)
1075                         rule->oifindex = -1;
1076         }
1077 }
1078
1079
1080 static int fib_rules_event(struct notifier_block *this, unsigned long event,
1081                            void *ptr)
1082 {
1083         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1084         struct net *net = dev_net(dev);
1085         struct fib_rules_ops *ops;
1086
1087         ASSERT_RTNL();
1088
1089         switch (event) {
1090         case NETDEV_REGISTER:
1091                 list_for_each_entry(ops, &net->rules_ops, list)
1092                         attach_rules(&ops->rules_list, dev);
1093                 break;
1094
1095         case NETDEV_CHANGENAME:
1096                 list_for_each_entry(ops, &net->rules_ops, list) {
1097                         detach_rules(&ops->rules_list, dev);
1098                         attach_rules(&ops->rules_list, dev);
1099                 }
1100                 break;
1101
1102         case NETDEV_UNREGISTER:
1103                 list_for_each_entry(ops, &net->rules_ops, list)
1104                         detach_rules(&ops->rules_list, dev);
1105                 break;
1106         }
1107
1108         return NOTIFY_DONE;
1109 }
1110
1111 static struct notifier_block fib_rules_notifier = {
1112         .notifier_call = fib_rules_event,
1113 };
1114
1115 static int __net_init fib_rules_net_init(struct net *net)
1116 {
1117         INIT_LIST_HEAD(&net->rules_ops);
1118         spin_lock_init(&net->rules_mod_lock);
1119         return 0;
1120 }
1121
1122 static void __net_exit fib_rules_net_exit(struct net *net)
1123 {
1124         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1125 }
1126
1127 static struct pernet_operations fib_rules_net_ops = {
1128         .init = fib_rules_net_init,
1129         .exit = fib_rules_net_exit,
1130 };
1131
1132 static int __init fib_rules_init(void)
1133 {
1134         int err;
1135         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1136         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1137         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1138
1139         err = register_pernet_subsys(&fib_rules_net_ops);
1140         if (err < 0)
1141                 goto fail;
1142
1143         err = register_netdevice_notifier(&fib_rules_notifier);
1144         if (err < 0)
1145                 goto fail_unregister;
1146
1147         return 0;
1148
1149 fail_unregister:
1150         unregister_pernet_subsys(&fib_rules_net_ops);
1151 fail:
1152         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1153         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1154         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1155         return err;
1156 }
1157
1158 subsys_initcall(fib_rules_init);