net/core/fib_rules.c

   1 /*
   2  * net/core/fib_rules.c         Generic Routing Rules
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License as
   6  *      published by the Free Software Foundation, version 2.
   7  *
   8  * Authors:     Thomas Graf <tgraf@suug.ch>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/list.h>
  15 #include <linux/module.h>
  16 #include <net/net_namespace.h>
  17 #include <net/sock.h>
  18 #include <net/fib_rules.h>
  19 #include <net/ip_tunnels.h>
  20
  21 static const struct fib_kuid_range fib_kuid_range_unset = {
  22         KUIDT_INIT(0),
  23         KUIDT_INIT(~0),
  24 };
  25
  26 bool fib_rule_matchall(const struct fib_rule *rule)
  27 {
  28         if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
  29             rule->flags)
  30                 return false;
  31         if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
  32                 return false;
  33         if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
  34             !uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
  35                 return false;
  36         return true;
  37 }
  38 EXPORT_SYMBOL_GPL(fib_rule_matchall);
  39
  40 int fib_default_rule_add(struct fib_rules_ops *ops,
  41                          u32 pref, u32 table, u32 flags)
  42 {
  43         struct fib_rule *r;
  44
  45         r = kzalloc(ops->rule_size, GFP_KERNEL);
  46         if (r == NULL)
  47                 return -ENOMEM;
  48
  49         refcount_set(&r->refcnt, 1);
  50         r->action = FR_ACT_TO_TBL;
  51         r->pref = pref;
  52         r->table = table;
  53         r->flags = flags;
  54         r->fr_net = ops->fro_net;
  55         r->uid_range = fib_kuid_range_unset;
  56
  57         r->suppress_prefixlen = -1;
  58         r->suppress_ifgroup = -1;
  59
  60         /* The lock is not required here, the list in unreacheable
  61          * at the moment this function is called */
  62         list_add_tail(&r->list, &ops->rules_list);
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(fib_default_rule_add);
  66
  67 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  68 {
  69         struct list_head *pos;
  70         struct fib_rule *rule;
  71
  72         if (!list_empty(&ops->rules_list)) {
  73                 pos = ops->rules_list.next;
  74                 if (pos->next != &ops->rules_list) {
  75                         rule = list_entry(pos->next, struct fib_rule, list);
  76                         if (rule->pref)
  77                                 return rule->pref - 1;
  78                 }
  79         }
  80
  81         return 0;
  82 }
  83
  84 static void notify_rule_change(int event, struct fib_rule *rule,
  85                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  86                                u32 pid);
  87
  88 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
  89 {
  90         struct fib_rules_ops *ops;
  91
  92         rcu_read_lock();
  93         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
  94                 if (ops->family == family) {
  95                         if (!try_module_get(ops->owner))
  96                                 ops = NULL;
  97                         rcu_read_unlock();
  98                         return ops;
  99                 }
 100         }
 101         rcu_read_unlock();
 102
 103         return NULL;
 104 }
 105
 106 static void rules_ops_put(struct fib_rules_ops *ops)
 107 {
 108         if (ops)
 109                 module_put(ops->owner);
 110 }
 111
 112 static void flush_route_cache(struct fib_rules_ops *ops)
 113 {
 114         if (ops->flush_cache)
 115                 ops->flush_cache(ops);
 116 }
 117
 118 static int __fib_rules_register(struct fib_rules_ops *ops)
 119 {
 120         int err = -EEXIST;
 121         struct fib_rules_ops *o;
 122         struct net *net;
 123
 124         net = ops->fro_net;
 125
 126         if (ops->rule_size < sizeof(struct fib_rule))
 127                 return -EINVAL;
 128
 129         if (ops->match == NULL || ops->configure == NULL ||
 130             ops->compare == NULL || ops->fill == NULL ||
 131             ops->action == NULL)
 132                 return -EINVAL;
 133
 134         spin_lock(&net->rules_mod_lock);
 135         list_for_each_entry(o, &net->rules_ops, list)
 136                 if (ops->family == o->family)
 137                         goto errout;
 138
 139         list_add_tail_rcu(&ops->list, &net->rules_ops);
 140         err = 0;
 141 errout:
 142         spin_unlock(&net->rules_mod_lock);
 143
 144         return err;
 145 }
 146
 147 struct fib_rules_ops *
 148 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 149 {
 150         struct fib_rules_ops *ops;
 151         int err;
 152
 153         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 154         if (ops == NULL)
 155                 return ERR_PTR(-ENOMEM);
 156
 157         INIT_LIST_HEAD(&ops->rules_list);
 158         ops->fro_net = net;
 159
 160         err = __fib_rules_register(ops);
 161         if (err) {
 162                 kfree(ops);
 163                 ops = ERR_PTR(err);
 164         }
 165
 166         return ops;
 167 }
 168 EXPORT_SYMBOL_GPL(fib_rules_register);
 169
 170 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 171 {
 172         struct fib_rule *rule, *tmp;
 173
 174         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 175                 list_del_rcu(&rule->list);
 176                 if (ops->delete)
 177                         ops->delete(rule);
 178                 fib_rule_put(rule);
 179         }
 180 }
 181
 182 void fib_rules_unregister(struct fib_rules_ops *ops)
 183 {
 184         struct net *net = ops->fro_net;
 185
 186         spin_lock(&net->rules_mod_lock);
 187         list_del_rcu(&ops->list);
 188         spin_unlock(&net->rules_mod_lock);
 189
 190         fib_rules_cleanup_ops(ops);
 191         kfree_rcu(ops, rcu);
 192 }
 193 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 194
 195 static int uid_range_set(struct fib_kuid_range *range)
 196 {
 197         return uid_valid(range->start) && uid_valid(range->end);
 198 }
 199
 200 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
 201 {
 202         struct fib_rule_uid_range *in;
 203         struct fib_kuid_range out;
 204
 205         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
 206
 207         out.start = make_kuid(current_user_ns(), in->start);
 208         out.end = make_kuid(current_user_ns(), in->end);
 209
 210         return out;
 211 }
 212
 213 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
 214 {
 215         struct fib_rule_uid_range out = {
 216                 from_kuid_munged(current_user_ns(), range->start),
 217                 from_kuid_munged(current_user_ns(), range->end)
 218         };
 219
 220         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
 221 }
 222
 223 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 224                           struct flowi *fl, int flags,
 225                           struct fib_lookup_arg *arg)
 226 {
 227         int ret = 0;
 228
 229         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 230                 goto out;
 231
 232         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 233                 goto out;
 234
 235         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 236                 goto out;
 237
 238         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
 239                 goto out;
 240
 241         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
 242                 goto out;
 243
 244         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
 245             uid_gt(fl->flowi_uid, rule->uid_range.end))
 246                 goto out;
 247
 248         ret = ops->match(rule, fl, flags);
 249 out:
 250         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 251 }
 252
 253 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 254                      int flags, struct fib_lookup_arg *arg)
 255 {
 256         struct fib_rule *rule;
 257         int err;
 258
 259         rcu_read_lock();
 260
 261         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 262 jumped:
 263                 if (!fib_rule_match(rule, ops, fl, flags, arg))
 264                         continue;
 265
 266                 if (rule->action == FR_ACT_GOTO) {
 267                         struct fib_rule *target;
 268
 269                         target = rcu_dereference(rule->ctarget);
 270                         if (target == NULL) {
 271                                 continue;
 272                         } else {
 273                                 rule = target;
 274                                 goto jumped;
 275                         }
 276                 } else if (rule->action == FR_ACT_NOP)
 277                         continue;
 278                 else
 279                         err = ops->action(rule, fl, flags, arg);
 280
 281                 if (!err && ops->suppress && ops->suppress(rule, arg))
 282                         continue;
 283
 284                 if (err != -EAGAIN) {
 285                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 286                             likely(refcount_inc_not_zero(&rule->refcnt))) {
 287                                 arg->rule = rule;
 288                                 goto out;
 289                         }
 290                         break;
 291                 }
 292         }
 293
 294         err = -ESRCH;
 295 out:
 296         rcu_read_unlock();
 297
 298         return err;
 299 }
 300 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 301
 302 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 303                             struct fib_rules_ops *ops)
 304 {
 305         int err = -EINVAL;
 306
 307         if (frh->src_len)
 308                 if (tb[FRA_SRC] == NULL ||
 309                     frh->src_len > (ops->addr_size * 8) ||
 310                     nla_len(tb[FRA_SRC]) != ops->addr_size)
 311                         goto errout;
 312
 313         if (frh->dst_len)
 314                 if (tb[FRA_DST] == NULL ||
 315                     frh->dst_len > (ops->addr_size * 8) ||
 316                     nla_len(tb[FRA_DST]) != ops->addr_size)
 317                         goto errout;
 318
 319         err = 0;
 320 errout:
 321         return err;
 322 }
 323
 324 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 325                        struct nlattr **tb, struct fib_rule *rule)
 326 {
 327         struct fib_rule *r;
 328
 329         list_for_each_entry(r, &ops->rules_list, list) {
 330                 if (r->action != rule->action)
 331                         continue;
 332
 333                 if (r->table != rule->table)
 334                         continue;
 335
 336                 if (r->pref != rule->pref)
 337                         continue;
 338
 339                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 340                         continue;
 341
 342                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 343                         continue;
 344
 345                 if (r->mark != rule->mark)
 346                         continue;
 347
 348                 if (r->mark_mask != rule->mark_mask)
 349                         continue;
 350
 351                 if (r->tun_id != rule->tun_id)
 352                         continue;
 353
 354                 if (r->fr_net != rule->fr_net)
 355                         continue;
 356
 357                 if (r->l3mdev != rule->l3mdev)
 358                         continue;
 359
 360                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 361                     !uid_eq(r->uid_range.end, rule->uid_range.end))
 362                         continue;
 363
 364                 if (!ops->compare(r, frh, tb))
 365                         continue;
 366                 return 1;
 367         }
 368         return 0;
 369 }
 370
 371 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 372                    struct netlink_ext_ack *extack)
 373 {
 374         struct net *net = sock_net(skb->sk);
 375         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 376         struct fib_rules_ops *ops = NULL;
 377         struct fib_rule *rule, *r, *last = NULL;
 378         struct nlattr *tb[FRA_MAX+1];
 379         int err = -EINVAL, unresolved = 0;
 380
 381         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 382                 goto errout;
 383
 384         ops = lookup_rules_ops(net, frh->family);
 385         if (ops == NULL) {
 386                 err = -EAFNOSUPPORT;
 387                 goto errout;
 388         }
 389
 390         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 391         if (err < 0)
 392                 goto errout;
 393
 394         err = validate_rulemsg(frh, tb, ops);
 395         if (err < 0)
 396                 goto errout;
 397
 398         rule = kzalloc(ops->rule_size, GFP_KERNEL);
 399         if (rule == NULL) {
 400                 err = -ENOMEM;
 401                 goto errout;
 402         }
 403         rule->fr_net = net;
 404
 405         rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 406                                       : fib_default_rule_pref(ops);
 407
 408         if (tb[FRA_IIFNAME]) {
 409                 struct net_device *dev;
 410
 411                 rule->iifindex = -1;
 412                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 413                 dev = __dev_get_by_name(net, rule->iifname);
 414                 if (dev)
 415                         rule->iifindex = dev->ifindex;
 416         }
 417
 418         if (tb[FRA_OIFNAME]) {
 419                 struct net_device *dev;
 420
 421                 rule->oifindex = -1;
 422                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 423                 dev = __dev_get_by_name(net, rule->oifname);
 424                 if (dev)
 425                         rule->oifindex = dev->ifindex;
 426         }
 427
 428         if (tb[FRA_FWMARK]) {
 429                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 430                 if (rule->mark)
 431                         /* compatibility: if the mark value is non-zero all bits
 432                          * are compared unless a mask is explicitly specified.
 433                          */
 434                         rule->mark_mask = 0xFFFFFFFF;
 435         }
 436
 437         if (tb[FRA_FWMASK])
 438                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 439
 440         if (tb[FRA_TUN_ID])
 441                 rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 442
 443         err = -EINVAL;
 444         if (tb[FRA_L3MDEV]) {
 445 #ifdef CONFIG_NET_L3_MASTER_DEV
 446                 rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
 447                 if (rule->l3mdev != 1)
 448 #endif
 449                         goto errout_free;
 450         }
 451
 452         rule->action = frh->action;
 453         rule->flags = frh->flags;
 454         rule->table = frh_get_table(frh, tb);
 455         if (tb[FRA_SUPPRESS_PREFIXLEN])
 456                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 457         else
 458                 rule->suppress_prefixlen = -1;
 459
 460         if (tb[FRA_SUPPRESS_IFGROUP])
 461                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 462         else
 463                 rule->suppress_ifgroup = -1;
 464
 465         if (tb[FRA_GOTO]) {
 466                 if (rule->action != FR_ACT_GOTO)
 467                         goto errout_free;
 468
 469                 rule->target = nla_get_u32(tb[FRA_GOTO]);
 470                 /* Backward jumps are prohibited to avoid endless loops */
 471                 if (rule->target <= rule->pref)
 472                         goto errout_free;
 473
 474                 list_for_each_entry(r, &ops->rules_list, list) {
 475                         if (r->pref == rule->target) {
 476                                 RCU_INIT_POINTER(rule->ctarget, r);
 477                                 break;
 478                         }
 479                 }
 480
 481                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 482                         unresolved = 1;
 483         } else if (rule->action == FR_ACT_GOTO)
 484                 goto errout_free;
 485
 486         if (rule->l3mdev && rule->table)
 487                 goto errout_free;
 488
 489         if (tb[FRA_UID_RANGE]) {
 490                 if (current_user_ns() != net->user_ns) {
 491                         err = -EPERM;
 492                         goto errout_free;
 493                 }
 494
 495                 rule->uid_range = nla_get_kuid_range(tb);
 496
 497                 if (!uid_range_set(&rule->uid_range) ||
 498                     !uid_lte(rule->uid_range.start, rule->uid_range.end))
 499                         goto errout_free;
 500         } else {
 501                 rule->uid_range = fib_kuid_range_unset;
 502         }
 503
 504         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 505             rule_exists(ops, frh, tb, rule)) {
 506                 err = -EEXIST;
 507                 goto errout_free;
 508         }
 509
 510         err = ops->configure(rule, skb, frh, tb);
 511         if (err < 0)
 512                 goto errout_free;
 513
 514         list_for_each_entry(r, &ops->rules_list, list) {
 515                 if (r->pref > rule->pref)
 516                         break;
 517                 last = r;
 518         }
 519
 520         refcount_set(&rule->refcnt, 1);
 521
 522         if (last)
 523                 list_add_rcu(&rule->list, &last->list);
 524         else
 525                 list_add_rcu(&rule->list, &ops->rules_list);
 526
 527         if (ops->unresolved_rules) {
 528                 /*
 529                  * There are unresolved goto rules in the list, check if
 530                  * any of them are pointing to this new rule.
 531                  */
 532                 list_for_each_entry(r, &ops->rules_list, list) {
 533                         if (r->action == FR_ACT_GOTO &&
 534                             r->target == rule->pref &&
 535                             rtnl_dereference(r->ctarget) == NULL) {
 536                                 rcu_assign_pointer(r->ctarget, rule);
 537                                 if (--ops->unresolved_rules == 0)
 538                                         break;
 539                         }
 540                 }
 541         }
 542
 543         if (rule->action == FR_ACT_GOTO)
 544                 ops->nr_goto_rules++;
 545
 546         if (unresolved)
 547                 ops->unresolved_rules++;
 548
 549         if (rule->tun_id)
 550                 ip_tunnel_need_metadata();
 551
 552         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 553         flush_route_cache(ops);
 554         rules_ops_put(ops);
 555         return 0;
 556
 557 errout_free:
 558         kfree(rule);
 559 errout:
 560         rules_ops_put(ops);
 561         return err;
 562 }
 563 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 564
 565 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 566                    struct netlink_ext_ack *extack)
 567 {
 568         struct net *net = sock_net(skb->sk);
 569         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 570         struct fib_rules_ops *ops = NULL;
 571         struct fib_rule *rule, *r;
 572         struct nlattr *tb[FRA_MAX+1];
 573         struct fib_kuid_range range;
 574         int err = -EINVAL;
 575
 576         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 577                 goto errout;
 578
 579         ops = lookup_rules_ops(net, frh->family);
 580         if (ops == NULL) {
 581                 err = -EAFNOSUPPORT;
 582                 goto errout;
 583         }
 584
 585         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 586         if (err < 0)
 587                 goto errout;
 588
 589         err = validate_rulemsg(frh, tb, ops);
 590         if (err < 0)
 591                 goto errout;
 592
 593         if (tb[FRA_UID_RANGE]) {
 594                 range = nla_get_kuid_range(tb);
 595                 if (!uid_range_set(&range)) {
 596                         err = -EINVAL;
 597                         goto errout;
 598                 }
 599         } else {
 600                 range = fib_kuid_range_unset;
 601         }
 602
 603         list_for_each_entry(rule, &ops->rules_list, list) {
 604                 if (frh->action && (frh->action != rule->action))
 605                         continue;
 606
 607                 if (frh_get_table(frh, tb) &&
 608                     (frh_get_table(frh, tb) != rule->table))
 609                         continue;
 610
 611                 if (tb[FRA_PRIORITY] &&
 612                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 613                         continue;
 614
 615                 if (tb[FRA_IIFNAME] &&
 616                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 617                         continue;
 618
 619                 if (tb[FRA_OIFNAME] &&
 620                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 621                         continue;
 622
 623                 if (tb[FRA_FWMARK] &&
 624                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 625                         continue;
 626
 627                 if (tb[FRA_FWMASK] &&
 628                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 629                         continue;
 630
 631                 if (tb[FRA_TUN_ID] &&
 632                     (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
 633                         continue;
 634
 635                 if (tb[FRA_L3MDEV] &&
 636                     (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
 637                         continue;
 638
 639                 if (uid_range_set(&range) &&
 640                     (!uid_eq(rule->uid_range.start, range.start) ||
 641                      !uid_eq(rule->uid_range.end, range.end)))
 642                         continue;
 643
 644                 if (!ops->compare(rule, frh, tb))
 645                         continue;
 646
 647                 if (rule->flags & FIB_RULE_PERMANENT) {
 648                         err = -EPERM;
 649                         goto errout;
 650                 }
 651
 652                 if (ops->delete) {
 653                         err = ops->delete(rule);
 654                         if (err)
 655                                 goto errout;
 656                 }
 657
 658                 if (rule->tun_id)
 659                         ip_tunnel_unneed_metadata();
 660
 661                 list_del_rcu(&rule->list);
 662
 663                 if (rule->action == FR_ACT_GOTO) {
 664                         ops->nr_goto_rules--;
 665                         if (rtnl_dereference(rule->ctarget) == NULL)
 666                                 ops->unresolved_rules--;
 667                 }
 668
 669                 /*
 670                  * Check if this rule is a target to any of them. If so,
 671                  * adjust to the next one with the same preference or
 672                  * disable them. As this operation is eventually very
 673                  * expensive, it is only performed if goto rules, except
 674                  * current if it is goto rule, have actually been added.
 675                  */
 676                 if (ops->nr_goto_rules > 0) {
 677                         struct fib_rule *n;
 678
 679                         n = list_next_entry(rule, list);
 680                         if (&n->list == &ops->rules_list || n->pref != rule->pref)
 681                                 n = NULL;
 682                         list_for_each_entry(r, &ops->rules_list, list) {
 683                                 if (rtnl_dereference(r->ctarget) != rule)
 684                                         continue;
 685                                 rcu_assign_pointer(r->ctarget, n);
 686                                 if (!n)
 687                                         ops->unresolved_rules++;
 688                         }
 689                 }
 690
 691                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 692                                    NETLINK_CB(skb).portid);
 693                 fib_rule_put(rule);
 694                 flush_route_cache(ops);
 695                 rules_ops_put(ops);
 696                 return 0;
 697         }
 698
 699         err = -ENOENT;
 700 errout:
 701         rules_ops_put(ops);
 702         return err;
 703 }
 704 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 705
 706 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 707                                          struct fib_rule *rule)
 708 {
 709         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 710                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 711                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 712                          + nla_total_size(4) /* FRA_PRIORITY */
 713                          + nla_total_size(4) /* FRA_TABLE */
 714                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 715                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 716                          + nla_total_size(4) /* FRA_FWMARK */
 717                          + nla_total_size(4) /* FRA_FWMASK */
 718                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 719                          + nla_total_size(sizeof(struct fib_kuid_range));
 720
 721         if (ops->nlmsg_payload)
 722                 payload += ops->nlmsg_payload(rule);
 723
 724         return payload;
 725 }
 726
 727 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 728                             u32 pid, u32 seq, int type, int flags,
 729                             struct fib_rules_ops *ops)
 730 {
 731         struct nlmsghdr *nlh;
 732         struct fib_rule_hdr *frh;
 733
 734         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 735         if (nlh == NULL)
 736                 return -EMSGSIZE;
 737
 738         frh = nlmsg_data(nlh);
 739         frh->family = ops->family;
 740         frh->table = rule->table;
 741         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 742                 goto nla_put_failure;
 743         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 744                 goto nla_put_failure;
 745         frh->res1 = 0;
 746         frh->res2 = 0;
 747         frh->action = rule->action;
 748         frh->flags = rule->flags;
 749
 750         if (rule->action == FR_ACT_GOTO &&
 751             rcu_access_pointer(rule->ctarget) == NULL)
 752                 frh->flags |= FIB_RULE_UNRESOLVED;
 753
 754         if (rule->iifname[0]) {
 755                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 756                         goto nla_put_failure;
 757                 if (rule->iifindex == -1)
 758                         frh->flags |= FIB_RULE_IIF_DETACHED;
 759         }
 760
 761         if (rule->oifname[0]) {
 762                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 763                         goto nla_put_failure;
 764                 if (rule->oifindex == -1)
 765                         frh->flags |= FIB_RULE_OIF_DETACHED;
 766         }
 767
 768         if ((rule->pref &&
 769              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 770             (rule->mark &&
 771              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 772             ((rule->mark_mask || rule->mark) &&
 773              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 774             (rule->target &&
 775              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 776             (rule->tun_id &&
 777              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 778             (rule->l3mdev &&
 779              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
 780             (uid_range_set(&rule->uid_range) &&
 781              nla_put_uid_range(skb, &rule->uid_range)))
 782                 goto nla_put_failure;
 783
 784         if (rule->suppress_ifgroup != -1) {
 785                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 786                         goto nla_put_failure;
 787         }
 788
 789         if (ops->fill(rule, skb, frh) < 0)
 790                 goto nla_put_failure;
 791
 792         nlmsg_end(skb, nlh);
 793         return 0;
 794
 795 nla_put_failure:
 796         nlmsg_cancel(skb, nlh);
 797         return -EMSGSIZE;
 798 }
 799
 800 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 801                       struct fib_rules_ops *ops)
 802 {
 803         int idx = 0;
 804         struct fib_rule *rule;
 805         int err = 0;
 806
 807         rcu_read_lock();
 808         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 809                 if (idx < cb->args[1])
 810                         goto skip;
 811
 812                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 813                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
 814                                        NLM_F_MULTI, ops);
 815                 if (err)
 816                         break;
 817 skip:
 818                 idx++;
 819         }
 820         rcu_read_unlock();
 821         cb->args[1] = idx;
 822         rules_ops_put(ops);
 823
 824         return err;
 825 }
 826
 827 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 828 {
 829         struct net *net = sock_net(skb->sk);
 830         struct fib_rules_ops *ops;
 831         int idx = 0, family;
 832
 833         family = rtnl_msg_family(cb->nlh);
 834         if (family != AF_UNSPEC) {
 835                 /* Protocol specific dump request */
 836                 ops = lookup_rules_ops(net, family);
 837                 if (ops == NULL)
 838                         return -EAFNOSUPPORT;
 839
 840                 dump_rules(skb, cb, ops);
 841
 842                 return skb->len;
 843         }
 844
 845         rcu_read_lock();
 846         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 847                 if (idx < cb->args[0] || !try_module_get(ops->owner))
 848                         goto skip;
 849
 850                 if (dump_rules(skb, cb, ops) < 0)
 851                         break;
 852
 853                 cb->args[1] = 0;
 854 skip:
 855                 idx++;
 856         }
 857         rcu_read_unlock();
 858         cb->args[0] = idx;
 859
 860         return skb->len;
 861 }
 862
 863 static void notify_rule_change(int event, struct fib_rule *rule,
 864                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 865                                u32 pid)
 866 {
 867         struct net *net;
 868         struct sk_buff *skb;
 869         int err = -ENOBUFS;
 870
 871         net = ops->fro_net;
 872         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 873         if (skb == NULL)
 874                 goto errout;
 875
 876         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 877         if (err < 0) {
 878                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 879                 WARN_ON(err == -EMSGSIZE);
 880                 kfree_skb(skb);
 881                 goto errout;
 882         }
 883
 884         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 885         return;
 886 errout:
 887         if (err < 0)
 888                 rtnl_set_sk_err(net, ops->nlgroup, err);
 889 }
 890
 891 static void attach_rules(struct list_head *rules, struct net_device *dev)
 892 {
 893         struct fib_rule *rule;
 894
 895         list_for_each_entry(rule, rules, list) {
 896                 if (rule->iifindex == -1 &&
 897                     strcmp(dev->name, rule->iifname) == 0)
 898                         rule->iifindex = dev->ifindex;
 899                 if (rule->oifindex == -1 &&
 900                     strcmp(dev->name, rule->oifname) == 0)
 901                         rule->oifindex = dev->ifindex;
 902         }
 903 }
 904
 905 static void detach_rules(struct list_head *rules, struct net_device *dev)
 906 {
 907         struct fib_rule *rule;
 908
 909         list_for_each_entry(rule, rules, list) {
 910                 if (rule->iifindex == dev->ifindex)
 911                         rule->iifindex = -1;
 912                 if (rule->oifindex == dev->ifindex)
 913                         rule->oifindex = -1;
 914         }
 915 }
 916
 917
 918 static int fib_rules_event(struct notifier_block *this, unsigned long event,
 919                            void *ptr)
 920 {
 921         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 922         struct net *net = dev_net(dev);
 923         struct fib_rules_ops *ops;
 924
 925         ASSERT_RTNL();
 926
 927         switch (event) {
 928         case NETDEV_REGISTER:
 929                 list_for_each_entry(ops, &net->rules_ops, list)
 930                         attach_rules(&ops->rules_list, dev);
 931                 break;
 932
 933         case NETDEV_CHANGENAME:
 934                 list_for_each_entry(ops, &net->rules_ops, list) {
 935                         detach_rules(&ops->rules_list, dev);
 936                         attach_rules(&ops->rules_list, dev);
 937                 }
 938                 break;
 939
 940         case NETDEV_UNREGISTER:
 941                 list_for_each_entry(ops, &net->rules_ops, list)
 942                         detach_rules(&ops->rules_list, dev);
 943                 break;
 944         }
 945
 946         return NOTIFY_DONE;
 947 }
 948
 949 static struct notifier_block fib_rules_notifier = {
 950         .notifier_call = fib_rules_event,
 951 };
 952
 953 static int __net_init fib_rules_net_init(struct net *net)
 954 {
 955         INIT_LIST_HEAD(&net->rules_ops);
 956         spin_lock_init(&net->rules_mod_lock);
 957         return 0;
 958 }
 959
 960 static struct pernet_operations fib_rules_net_ops = {
 961         .init = fib_rules_net_init,
 962 };
 963
 964 static int __init fib_rules_init(void)
 965 {
 966         int err;
 967         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 968         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 969         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 970
 971         err = register_pernet_subsys(&fib_rules_net_ops);
 972         if (err < 0)
 973                 goto fail;
 974
 975         err = register_netdevice_notifier(&fib_rules_notifier);
 976         if (err < 0)
 977                 goto fail_unregister;
 978
 979         return 0;
 980
 981 fail_unregister:
 982         unregister_pernet_subsys(&fib_rules_net_ops);
 983 fail:
 984         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 985         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 986         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 987         return err;
 988 }
 989
 990 subsys_initcall(fib_rules_init);