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 int fib_default_rule_add(struct fib_rules_ops *ops,
  27                          u32 pref, u32 table, u32 flags)
  28 {
  29         struct fib_rule *r;
  30
  31         r = kzalloc(ops->rule_size, GFP_KERNEL);
  32         if (r == NULL)
  33                 return -ENOMEM;
  34
  35         atomic_set(&r->refcnt, 1);
  36         r->action = FR_ACT_TO_TBL;
  37         r->pref = pref;
  38         r->table = table;
  39         r->flags = flags;
  40         r->fr_net = ops->fro_net;
  41         r->uid_range = fib_kuid_range_unset;
  42
  43         r->suppress_prefixlen = -1;
  44         r->suppress_ifgroup = -1;
  45
  46         /* The lock is not required here, the list in unreacheable
  47          * at the moment this function is called */
  48         list_add_tail(&r->list, &ops->rules_list);
  49         return 0;
  50 }
  51 EXPORT_SYMBOL(fib_default_rule_add);
  52
  53 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  54 {
  55         struct list_head *pos;
  56         struct fib_rule *rule;
  57
  58         if (!list_empty(&ops->rules_list)) {
  59                 pos = ops->rules_list.next;
  60                 if (pos->next != &ops->rules_list) {
  61                         rule = list_entry(pos->next, struct fib_rule, list);
  62                         if (rule->pref)
  63                                 return rule->pref - 1;
  64                 }
  65         }
  66
  67         return 0;
  68 }
  69
  70 static void notify_rule_change(int event, struct fib_rule *rule,
  71                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  72                                u32 pid);
  73
  74 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  75 {
  76         struct fib_rules_ops *ops;
  77
  78         rcu_read_lock();
  79         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  80                 if (ops->family == family) {
  81                         if (!try_module_get(ops->owner))
  82                                 ops = NULL;
  83                         rcu_read_unlock();
  84                         return ops;
  85                 }
  86         }
  87         rcu_read_unlock();
  88
  89         return NULL;
  90 }
  91
  92 static void rules_ops_put(struct fib_rules_ops *ops)
  93 {
  94         if (ops)
  95                 module_put(ops->owner);
  96 }
  97
  98 static void flush_route_cache(struct fib_rules_ops *ops)
  99 {
 100         if (ops->flush_cache)
 101                 ops->flush_cache(ops);
 102 }
 103
 104 static int __fib_rules_register(struct fib_rules_ops *ops)
 105 {
 106         int err = -EEXIST;
 107         struct fib_rules_ops *o;
 108         struct net *net;
 109
 110         net = ops->fro_net;
 111
 112         if (ops->rule_size < sizeof(struct fib_rule))
 113                 return -EINVAL;
 114
 115         if (ops->match == NULL || ops->configure == NULL ||
 116             ops->compare == NULL || ops->fill == NULL ||
 117             ops->action == NULL)
 118                 return -EINVAL;
 119
 120         spin_lock(&net->rules_mod_lock);
 121         list_for_each_entry(o, &net->rules_ops, list)
 122                 if (ops->family == o->family)
 123                         goto errout;
 124
 125         list_add_tail_rcu(&ops->list, &net->rules_ops);
 126         err = 0;
 127 errout:
 128         spin_unlock(&net->rules_mod_lock);
 129
 130         return err;
 131 }
 132
 133 struct fib_rules_ops *
 134 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 135 {
 136         struct fib_rules_ops *ops;
 137         int err;
 138
 139         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 140         if (ops == NULL)
 141                 return ERR_PTR(-ENOMEM);
 142
 143         INIT_LIST_HEAD(&ops->rules_list);
 144         ops->fro_net = net;
 145
 146         err = __fib_rules_register(ops);
 147         if (err) {
 148                 kfree(ops);
 149                 ops = ERR_PTR(err);
 150         }
 151
 152         return ops;
 153 }
 154 EXPORT_SYMBOL_GPL(fib_rules_register);
 155
 156 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 157 {
 158         struct fib_rule *rule, *tmp;
 159
 160         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 161                 list_del_rcu(&rule->list);
 162                 if (ops->delete)
 163                         ops->delete(rule);
 164                 fib_rule_put(rule);
 165         }
 166 }
 167
 168 void fib_rules_unregister(struct fib_rules_ops *ops)
 169 {
 170         struct net *net = ops->fro_net;
 171
 172         spin_lock(&net->rules_mod_lock);
 173         list_del_rcu(&ops->list);
 174         spin_unlock(&net->rules_mod_lock);
 175
 176         fib_rules_cleanup_ops(ops);
 177         kfree_rcu(ops, rcu);
 178 }
 179 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 180
 181 static int uid_range_set(struct fib_kuid_range *range)
 182 {
 183         return uid_valid(range->start) && uid_valid(range->end);
 184 }
 185
 186 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
 187 {
 188         struct fib_rule_uid_range *in;
 189         struct fib_kuid_range out;
 190
 191         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
 192
 193         out.start = make_kuid(current_user_ns(), in->start);
 194         out.end = make_kuid(current_user_ns(), in->end);
 195
 196         return out;
 197 }
 198
 199 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
 200 {
 201         struct fib_rule_uid_range out = {
 202                 from_kuid_munged(current_user_ns(), range->start),
 203                 from_kuid_munged(current_user_ns(), range->end)
 204         };
 205
 206         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
 207 }
 208
 209 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 210                           struct flowi *fl, int flags,
 211                           struct fib_lookup_arg *arg)
 212 {
 213         int ret = 0;
 214
 215         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 216                 goto out;
 217
 218         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 219                 goto out;
 220
 221         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 222                 goto out;
 223
 224         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
 225                 goto out;
 226
 227         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
 228                 goto out;
 229
 230         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
 231             uid_gt(fl->flowi_uid, rule->uid_range.end))
 232                 goto out;
 233
 234         ret = ops->match(rule, fl, flags);
 235 out:
 236         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 237 }
 238
 239 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 240                      int flags, struct fib_lookup_arg *arg)
 241 {
 242         struct fib_rule *rule;
 243         int err;
 244
 245         rcu_read_lock();
 246
 247         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 248 jumped:
 249                 if (!fib_rule_match(rule, ops, fl, flags, arg))
 250                         continue;
 251
 252                 if (rule->action == FR_ACT_GOTO) {
 253                         struct fib_rule *target;
 254
 255                         target = rcu_dereference(rule->ctarget);
 256                         if (target == NULL) {
 257                                 continue;
 258                         } else {
 259                                 rule = target;
 260                                 goto jumped;
 261                         }
 262                 } else if (rule->action == FR_ACT_NOP)
 263                         continue;
 264                 else
 265                         err = ops->action(rule, fl, flags, arg);
 266
 267                 if (!err && ops->suppress && ops->suppress(rule, arg))
 268                         continue;
 269
 270                 if (err != -EAGAIN) {
 271                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 272                             likely(atomic_inc_not_zero(&rule->refcnt))) {
 273                                 arg->rule = rule;
 274                                 goto out;
 275                         }
 276                         break;
 277                 }
 278         }
 279
 280         err = -ESRCH;
 281 out:
 282         rcu_read_unlock();
 283
 284         return err;
 285 }
 286 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 287
 288 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 289                             struct fib_rules_ops *ops)
 290 {
 291         int err = -EINVAL;
 292
 293         if (frh->src_len)
 294                 if (tb[FRA_SRC] == NULL ||
 295                     frh->src_len > (ops->addr_size * 8) ||
 296                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 297                         goto errout;
 298
 299         if (frh->dst_len)
 300                 if (tb[FRA_DST] == NULL ||
 301                     frh->dst_len > (ops->addr_size * 8) ||
 302                     nla_len(tb[FRA_DST]) != ops->addr_size)
 303                         goto errout;
 304
 305         err = 0;
 306 errout:
 307         return err;
 308 }
 309
 310 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 311                        struct nlattr **tb, struct fib_rule *rule)
 312 {
 313         struct fib_rule *r;
 314
 315         list_for_each_entry(r, &ops->rules_list, list) {
 316                 if (r->action != rule->action)
 317                         continue;
 318
 319                 if (r->table != rule->table)
 320                         continue;
 321
 322                 if (r->pref != rule->pref)
 323                         continue;
 324
 325                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 326                         continue;
 327
 328                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 329                         continue;
 330
 331                 if (r->mark != rule->mark)
 332                         continue;
 333
 334                 if (r->mark_mask != rule->mark_mask)
 335                         continue;
 336
 337                 if (r->tun_id != rule->tun_id)
 338                         continue;
 339
 340                 if (r->fr_net != rule->fr_net)
 341                         continue;
 342
 343                 if (r->l3mdev != rule->l3mdev)
 344                         continue;
 345
 346                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 347                     !uid_eq(r->uid_range.end, rule->uid_range.end))
 348                         continue;
 349
 350                 if (!ops->compare(r, frh, tb))
 351                         continue;
 352                 return 1;
 353         }
 354         return 0;
 355 }
 356
 357 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh)
 358 {
 359         struct net *net = sock_net(skb->sk);
 360         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 361         struct fib_rules_ops *ops = NULL;
 362         struct fib_rule *rule, *r, *last = NULL;
 363         struct nlattr *tb[FRA_MAX+1];
 364         int err = -EINVAL, unresolved = 0;
 365
 366         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 367                 goto errout;
 368
 369         ops = lookup_rules_ops(net, frh->family);
 370         if (ops == NULL) {
 371                 err = -EAFNOSUPPORT;
 372                 goto errout;
 373         }
 374
 375         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 376         if (err < 0)
 377                 goto errout;
 378
 379         err = validate_rulemsg(frh, tb, ops);
 380         if (err < 0)
 381                 goto errout;
 382
 383         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 384         if (rule == NULL) {
 385                 err = -ENOMEM;
 386                 goto errout;
 387         }
 388         rule->fr_net = net;
 389
 390         rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 391                                       : fib_default_rule_pref(ops);
 392
 393         if (tb[FRA_IIFNAME]) {
 394                 struct net_device *dev;
 395
 396                 rule->iifindex = -1;
 397                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 398                 dev = __dev_get_by_name(net, rule->iifname);
 399                 if (dev)
 400                         rule->iifindex = dev->ifindex;
 401         }
 402
 403         if (tb[FRA_OIFNAME]) {
 404                 struct net_device *dev;
 405
 406                 rule->oifindex = -1;
 407                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 408                 dev = __dev_get_by_name(net, rule->oifname);
 409                 if (dev)
 410                         rule->oifindex = dev->ifindex;
 411         }
 412
 413         if (tb[FRA_FWMARK]) {
 414                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 415                 if (rule->mark)
 416                         /* compatibility: if the mark value is non-zero all bits
 417                          * are compared unless a mask is explicitly specified.
 418                          */
 419                         rule->mark_mask = 0xFFFFFFFF;
 420         }
 421
 422         if (tb[FRA_FWMASK])
 423                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 424
 425         if (tb[FRA_TUN_ID])
 426                 rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 427
 428         if (tb[FRA_L3MDEV]) {
 429 #ifdef CONFIG_NET_L3_MASTER_DEV
 430                 rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
 431                 if (rule->l3mdev != 1)
 432 #endif
 433                         goto errout_free;
 434         }
 435
 436         rule->action = frh->action;
 437         rule->flags = frh->flags;
 438         rule->table = frh_get_table(frh, tb);
 439         if (tb[FRA_SUPPRESS_PREFIXLEN])
 440                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 441         else
 442                 rule->suppress_prefixlen = -1;
 443
 444         if (tb[FRA_SUPPRESS_IFGROUP])
 445                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 446         else
 447                 rule->suppress_ifgroup = -1;
 448
 449         err = -EINVAL;
 450         if (tb[FRA_GOTO]) {
 451                 if (rule->action != FR_ACT_GOTO)
 452                         goto errout_free;
 453
 454                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 455                 /* Backward jumps are prohibited to avoid endless loops */
 456                 if (rule->target <= rule->pref)
 457                         goto errout_free;
 458
 459                 list_for_each_entry(r, &ops->rules_list, list) {
 460                         if (r->pref == rule->target) {
 461                                 RCU_INIT_POINTER(rule->ctarget, r);
 462                                 break;
 463                         }
 464                 }
 465
 466                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 467                         unresolved = 1;
 468         } else if (rule->action == FR_ACT_GOTO)
 469                 goto errout_free;
 470
 471         if (rule->l3mdev && rule->table)
 472                 goto errout_free;
 473
 474         if (tb[FRA_UID_RANGE]) {
 475                 if (current_user_ns() != net->user_ns) {
 476                         err = -EPERM;
 477                         goto errout_free;
 478                 }
 479
 480                 rule->uid_range = nla_get_kuid_range(tb);
 481
 482                 if (!uid_range_set(&rule->uid_range) ||
 483                     !uid_lte(rule->uid_range.start, rule->uid_range.end))
 484                         goto errout_free;
 485         } else {
 486                 rule->uid_range = fib_kuid_range_unset;
 487         }
 488
 489         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 490             rule_exists(ops, frh, tb, rule)) {
 491                 err = -EEXIST;
 492                 goto errout_free;
 493         }
 494
 495         err = ops->configure(rule, skb, frh, tb);
 496         if (err < 0)
 497                 goto errout_free;
 498
 499         list_for_each_entry(r, &ops->rules_list, list) {
 500                 if (r->pref > rule->pref)
 501                         break;
 502                 last = r;
 503         }
 504
 505         fib_rule_get(rule);
 506
 507         if (last)
 508                 list_add_rcu(&rule->list, &last->list);
 509         else
 510                 list_add_rcu(&rule->list, &ops->rules_list);
 511
 512         if (ops->unresolved_rules) {
 513                 /*
 514                  * There are unresolved goto rules in the list, check if
 515                  * any of them are pointing to this new rule.
 516                  */
 517                 list_for_each_entry(r, &ops->rules_list, list) {
 518                         if (r->action == FR_ACT_GOTO &&
 519                             r->target == rule->pref &&
 520                             rtnl_dereference(r->ctarget) == NULL) {
 521                                 rcu_assign_pointer(r->ctarget, rule);
 522                                 if (--ops->unresolved_rules == 0)
 523                                         break;
 524                         }
 525                 }
 526         }
 527
 528         if (rule->action == FR_ACT_GOTO)
 529                 ops->nr_goto_rules++;
 530
 531         if (unresolved)
 532                 ops->unresolved_rules++;
 533
 534         if (rule->tun_id)
 535                 ip_tunnel_need_metadata();
 536
 537         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 538         flush_route_cache(ops);
 539         rules_ops_put(ops);
 540         return 0;
 541
 542 errout_free:
 543         kfree(rule);
 544 errout:
 545         rules_ops_put(ops);
 546         return err;
 547 }
 548 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 549
 550 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh)
 551 {
 552         struct net *net = sock_net(skb->sk);
 553         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 554         struct fib_rules_ops *ops = NULL;
 555         struct fib_rule *rule, *tmp;
 556         struct nlattr *tb[FRA_MAX+1];
 557         struct fib_kuid_range range;
 558         int err = -EINVAL;
 559
 560         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 561                 goto errout;
 562
 563         ops = lookup_rules_ops(net, frh->family);
 564         if (ops == NULL) {
 565                 err = -EAFNOSUPPORT;
 566                 goto errout;
 567         }
 568
 569         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 570         if (err < 0)
 571                 goto errout;
 572
 573         err = validate_rulemsg(frh, tb, ops);
 574         if (err < 0)
 575                 goto errout;
 576
 577         if (tb[FRA_UID_RANGE]) {
 578                 range = nla_get_kuid_range(tb);
 579                 if (!uid_range_set(&range))
 580                         goto errout;
 581         } else {
 582                 range = fib_kuid_range_unset;
 583         }
 584
 585         list_for_each_entry(rule, &ops->rules_list, list) {
 586                 if (frh->action && (frh->action != rule->action))
 587                         continue;
 588
 589                 if (frh_get_table(frh, tb) &&
 590                     (frh_get_table(frh, tb) != rule->table))
 591                         continue;
 592
 593                 if (tb[FRA_PRIORITY] &&
 594                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 595                         continue;
 596
 597                 if (tb[FRA_IIFNAME] &&
 598                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 599                         continue;
 600
 601                 if (tb[FRA_OIFNAME] &&
 602                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 603                         continue;
 604
 605                 if (tb[FRA_FWMARK] &&
 606                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 607                         continue;
 608
 609                 if (tb[FRA_FWMASK] &&
 610                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 611                         continue;
 612
 613                 if (tb[FRA_TUN_ID] &&
 614                     (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
 615                         continue;
 616
 617                 if (tb[FRA_L3MDEV] &&
 618                     (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
 619                         continue;
 620
 621                 if (uid_range_set(&range) &&
 622                     (!uid_eq(rule->uid_range.start, range.start) ||
 623                      !uid_eq(rule->uid_range.end, range.end)))
 624                         continue;
 625
 626                 if (!ops->compare(rule, frh, tb))
 627                         continue;
 628
 629                 if (rule->flags & FIB_RULE_PERMANENT) {
 630                         err = -EPERM;
 631                         goto errout;
 632                 }
 633
 634                 if (ops->delete) {
 635                         err = ops->delete(rule);
 636                         if (err)
 637                                 goto errout;
 638                 }
 639
 640                 if (rule->tun_id)
 641                         ip_tunnel_unneed_metadata();
 642
 643                 list_del_rcu(&rule->list);
 644
 645                 if (rule->action == FR_ACT_GOTO) {
 646                         ops->nr_goto_rules--;
 647                         if (rtnl_dereference(rule->ctarget) == NULL)
 648                                 ops->unresolved_rules--;
 649                 }
 650
 651                 /*
 652                  * Check if this rule is a target to any of them. If so,
 653                  * disable them. As this operation is eventually very
 654                  * expensive, it is only performed if goto rules have
 655                  * actually been added.
 656                  */
 657                 if (ops->nr_goto_rules > 0) {
 658                         list_for_each_entry(tmp, &ops->rules_list, list) {
 659                                 if (rtnl_dereference(tmp->ctarget) == rule) {
 660                                         RCU_INIT_POINTER(tmp->ctarget, NULL);
 661                                         ops->unresolved_rules++;
 662                                 }
 663                         }
 664                 }
 665
 666                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 667                                    NETLINK_CB(skb).portid);
 668                 fib_rule_put(rule);
 669                 flush_route_cache(ops);
 670                 rules_ops_put(ops);
 671                 return 0;
 672         }
 673
 674         err = -ENOENT;
 675 errout:
 676         rules_ops_put(ops);
 677         return err;
 678 }
 679 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 680
 681 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 682                                          struct fib_rule *rule)
 683 {
 684         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 685                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 686                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 687                          + nla_total_size(4) /* FRA_PRIORITY */
 688                          + nla_total_size(4) /* FRA_TABLE */
 689                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 690                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 691                          + nla_total_size(4) /* FRA_FWMARK */
 692                          + nla_total_size(4) /* FRA_FWMASK */
 693                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 694                          + nla_total_size(sizeof(struct fib_kuid_range));
 695
 696         if (ops->nlmsg_payload)
 697                 payload += ops->nlmsg_payload(rule);
 698
 699         return payload;
 700 }
 701
 702 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 703                             u32 pid, u32 seq, int type, int flags,
 704                             struct fib_rules_ops *ops)
 705 {
 706         struct nlmsghdr *nlh;
 707         struct fib_rule_hdr *frh;
 708
 709         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 710         if (nlh == NULL)
 711                 return -EMSGSIZE;
 712
 713         frh = nlmsg_data(nlh);
 714         frh->family = ops->family;
 715         frh->table = rule->table;
 716         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 717                 goto nla_put_failure;
 718         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 719                 goto nla_put_failure;
 720         frh->res1 = 0;
 721         frh->res2 = 0;
 722         frh->action = rule->action;
 723         frh->flags = rule->flags;
 724
 725         if (rule->action == FR_ACT_GOTO &&
 726             rcu_access_pointer(rule->ctarget) == NULL)
 727                 frh->flags |= FIB_RULE_UNRESOLVED;
 728
 729         if (rule->iifname[0]) {
 730                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 731                         goto nla_put_failure;
 732                 if (rule->iifindex == -1)
 733                         frh->flags |= FIB_RULE_IIF_DETACHED;
 734         }
 735
 736         if (rule->oifname[0]) {
 737                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 738                         goto nla_put_failure;
 739                 if (rule->oifindex == -1)
 740                         frh->flags |= FIB_RULE_OIF_DETACHED;
 741         }
 742
 743         if ((rule->pref &&
 744              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 745             (rule->mark &&
 746              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 747             ((rule->mark_mask || rule->mark) &&
 748              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 749             (rule->target &&
 750              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 751             (rule->tun_id &&
 752              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 753             (rule->l3mdev &&
 754              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
 755             (uid_range_set(&rule->uid_range) &&
 756              nla_put_uid_range(skb, &rule->uid_range)))
 757                 goto nla_put_failure;
 758
 759         if (rule->suppress_ifgroup != -1) {
 760                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 761                         goto nla_put_failure;
 762         }
 763
 764         if (ops->fill(rule, skb, frh) < 0)
 765                 goto nla_put_failure;
 766
 767         nlmsg_end(skb, nlh);
 768         return 0;
 769
 770 nla_put_failure:
 771         nlmsg_cancel(skb, nlh);
 772         return -EMSGSIZE;
 773 }
 774
 775 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 776                       struct fib_rules_ops *ops)
 777 {
 778         int idx = 0;
 779         struct fib_rule *rule;
 780         int err = 0;
 781
 782         rcu_read_lock();
 783         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 784                 if (idx < cb->args[1])
 785                         goto skip;
 786
 787                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 788                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
 789                                        NLM_F_MULTI, ops);
 790                 if (err)
 791                         break;
 792 skip:
 793                 idx++;
 794         }
 795         rcu_read_unlock();
 796         cb->args[1] = idx;
 797         rules_ops_put(ops);
 798
 799         return err;
 800 }
 801
 802 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 803 {
 804         struct net *net = sock_net(skb->sk);
 805         struct fib_rules_ops *ops;
 806         int idx = 0, family;
 807
 808         family = rtnl_msg_family(cb->nlh);
 809         if (family != AF_UNSPEC) {
 810                 /* Protocol specific dump request */
 811                 ops = lookup_rules_ops(net, family);
 812                 if (ops == NULL)
 813                         return -EAFNOSUPPORT;
 814
 815                 dump_rules(skb, cb, ops);
 816
 817                 return skb->len;
 818         }
 819
 820         rcu_read_lock();
 821         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 822                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 823                         goto skip;
 824
 825                 if (dump_rules(skb, cb, ops) < 0)
 826                         break;
 827
 828                 cb->args[1] = 0;
 829 skip:
 830                 idx++;
 831         }
 832         rcu_read_unlock();
 833         cb->args[0] = idx;
 834
 835         return skb->len;
 836 }
 837
 838 static void notify_rule_change(int event, struct fib_rule *rule,
 839                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 840                                u32 pid)
 841 {
 842         struct net *net;
 843         struct sk_buff *skb;
 844         int err = -ENOBUFS;
 845
 846         net = ops->fro_net;
 847         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 848         if (skb == NULL)
 849                 goto errout;
 850
 851         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 852         if (err < 0) {
 853                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 854                 WARN_ON(err == -EMSGSIZE);
 855                 kfree_skb(skb);
 856                 goto errout;
 857         }
 858
 859         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 860         return;
 861 errout:
 862         if (err < 0)
 863                 rtnl_set_sk_err(net, ops->nlgroup, err);
 864 }
 865
 866 static void attach_rules(struct list_head *rules, struct net_device *dev)
 867 {
 868         struct fib_rule *rule;
 869
 870         list_for_each_entry(rule, rules, list) {
 871                 if (rule->iifindex == -1 &&
 872                     strcmp(dev->name, rule->iifname) == 0)
 873                         rule->iifindex = dev->ifindex;
 874                 if (rule->oifindex == -1 &&
 875                     strcmp(dev->name, rule->oifname) == 0)
 876                         rule->oifindex = dev->ifindex;
 877         }
 878 }
 879
 880 static void detach_rules(struct list_head *rules, struct net_device *dev)
 881 {
 882         struct fib_rule *rule;
 883
 884         list_for_each_entry(rule, rules, list) {
 885                 if (rule->iifindex == dev->ifindex)
 886                         rule->iifindex = -1;
 887                 if (rule->oifindex == dev->ifindex)
 888                         rule->oifindex = -1;
 889         }
 890 }
 891
 892
 893 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 894                            void *ptr)
 895 {
 896         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 897         struct net *net = dev_net(dev);
 898         struct fib_rules_ops *ops;
 899
 900         ASSERT_RTNL();
 901
 902         switch (event) {
 903         case NETDEV_REGISTER:
 904                 list_for_each_entry(ops, &net->rules_ops, list)
 905                         attach_rules(&ops->rules_list, dev);
 906                 break;
 907
 908         case NETDEV_CHANGENAME:
 909                 list_for_each_entry(ops, &net->rules_ops, list) {
 910                         detach_rules(&ops->rules_list, dev);
 911                         attach_rules(&ops->rules_list, dev);
 912                 }
 913                 break;
 914
 915         case NETDEV_UNREGISTER:
 916                 list_for_each_entry(ops, &net->rules_ops, list)
 917                         detach_rules(&ops->rules_list, dev);
 918                 break;
 919         }
 920
 921         return NOTIFY_DONE;
 922 }
 923
 924 static struct notifier_block fib_rules_notifier = {
 925         .notifier_call = fib_rules_event,
 926 };
 927
 928 static int __net_init fib_rules_net_init(struct net *net)
 929 {
 930         INIT_LIST_HEAD(&net->rules_ops);
 931         spin_lock_init(&net->rules_mod_lock);
 932         return 0;
 933 }
 934
 935 static struct pernet_operations fib_rules_net_ops = {
 936         .init = fib_rules_net_init,
 937 };
 938
 939 static int __init fib_rules_init(void)
 940 {
 941         int err;
 942         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 943         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 944         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 945
 946         err = register_pernet_subsys(&fib_rules_net_ops);
 947         if (err < 0)
 948                 goto fail;
 949
 950         err = register_netdevice_notifier(&fib_rules_notifier);
 951         if (err < 0)
 952                 goto fail_unregister;
 953
 954         return 0;
 955
 956 fail_unregister:
 957         unregister_pernet_subsys(&fib_rules_net_ops);
 958 fail:
 959         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 960         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 961         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 962         return err;
 963 }
 964
 965 subsys_initcall(fib_rules_init);