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