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
  20int fib_default_rule_add(struct fib_rules_ops *ops,
  21                         u32 pref, u32 table, u32 flags)
  22{
  23        struct fib_rule *r;
  24
  25        r = kzalloc(ops->rule_size, GFP_KERNEL);
  26        if (r == NULL)
  27                return -ENOMEM;
  28
  29        atomic_set(&r->refcnt, 1);
  30        r->action = FR_ACT_TO_TBL;
  31        r->pref = pref;
  32        r->table = table;
  33        r->flags = flags;
  34        r->fr_net = hold_net(ops->fro_net);
  35
  36        r->suppress_prefixlen = -1;
  37        r->suppress_ifgroup = -1;
  38
  39        /* The lock is not required here, the list in unreacheable
  40         * at the moment this function is called */
  41        list_add_tail(&r->list, &ops->rules_list);
  42        return 0;
  43}
  44EXPORT_SYMBOL(fib_default_rule_add);
  45
  46u32 fib_default_rule_pref(struct fib_rules_ops *ops)
  47{
  48        struct list_head *pos;
  49        struct fib_rule *rule;
  50
  51        if (!list_empty(&ops->rules_list)) {
  52                pos = ops->rules_list.next;
  53                if (pos->next != &ops->rules_list) {
  54                        rule = list_entry(pos->next, struct fib_rule, list);
  55                        if (rule->pref)
  56                                return rule->pref - 1;
  57                }
  58        }
  59
  60        return 0;
  61}
  62EXPORT_SYMBOL(fib_default_rule_pref);
  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        hold_net(net);
 120        list_add_tail_rcu(&ops->list, &net->rules_ops);
 121        err = 0;
 122errout:
 123        spin_unlock(&net->rules_mod_lock);
 124
 125        return err;
 126}
 127
 128struct fib_rules_ops *
 129fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
 130{
 131        struct fib_rules_ops *ops;
 132        int err;
 133
 134        ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
 135        if (ops == NULL)
 136                return ERR_PTR(-ENOMEM);
 137
 138        INIT_LIST_HEAD(&ops->rules_list);
 139        ops->fro_net = net;
 140
 141        err = __fib_rules_register(ops);
 142        if (err) {
 143                kfree(ops);
 144                ops = ERR_PTR(err);
 145        }
 146
 147        return ops;
 148}
 149EXPORT_SYMBOL_GPL(fib_rules_register);
 150
 151static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 152{
 153        struct fib_rule *rule, *tmp;
 154
 155        list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
 156                list_del_rcu(&rule->list);
 157                if (ops->delete)
 158                        ops->delete(rule);
 159                fib_rule_put(rule);
 160        }
 161}
 162
 163static void fib_rules_put_rcu(struct rcu_head *head)
 164{
 165        struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
 166        struct net *net = ops->fro_net;
 167
 168        release_net(net);
 169        kfree(ops);
 170}
 171
 172void fib_rules_unregister(struct fib_rules_ops *ops)
 173{
 174        struct net *net = ops->fro_net;
 175
 176        spin_lock(&net->rules_mod_lock);
 177        list_del_rcu(&ops->list);
 178        fib_rules_cleanup_ops(ops);
 179        spin_unlock(&net->rules_mod_lock);
 180
 181        call_rcu(&ops->rcu, fib_rules_put_rcu);
 182}
 183EXPORT_SYMBOL_GPL(fib_rules_unregister);
 184
 185static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 186                          struct flowi *fl, int flags)
 187{
 188        int ret = 0;
 189
 190        if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 191                goto out;
 192
 193        if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 194                goto out;
 195
 196        if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 197                goto out;
 198
 199        ret = ops->match(rule, fl, flags);
 200out:
 201        return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 202}
 203
 204int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 205                     int flags, struct fib_lookup_arg *arg)
 206{
 207        struct fib_rule *rule;
 208        int err;
 209
 210        rcu_read_lock();
 211
 212        list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 213jumped:
 214                if (!fib_rule_match(rule, ops, fl, flags))
 215                        continue;
 216
 217                if (rule->action == FR_ACT_GOTO) {
 218                        struct fib_rule *target;
 219
 220                        target = rcu_dereference(rule->ctarget);
 221                        if (target == NULL) {
 222                                continue;
 223                        } else {
 224                                rule = target;
 225                                goto jumped;
 226                        }
 227                } else if (rule->action == FR_ACT_NOP)
 228                        continue;
 229                else
 230                        err = ops->action(rule, fl, flags, arg);
 231
 232                if (!err && ops->suppress && ops->suppress(rule, arg))
 233                        continue;
 234
 235                if (err != -EAGAIN) {
 236                        if ((arg->flags & FIB_LOOKUP_NOREF) ||
 237                            likely(atomic_inc_not_zero(&rule->refcnt))) {
 238                                arg->rule = rule;
 239                                goto out;
 240                        }
 241                        break;
 242                }
 243        }
 244
 245        err = -ESRCH;
 246out:
 247        rcu_read_unlock();
 248
 249        return err;
 250}
 251EXPORT_SYMBOL_GPL(fib_rules_lookup);
 252
 253static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 254                            struct fib_rules_ops *ops)
 255{
 256        int err = -EINVAL;
 257
 258        if (frh->src_len)
 259                if (tb[FRA_SRC] == NULL ||
 260                    frh->src_len > (ops->addr_size * 8) ||
 261                    nla_len(tb[FRA_SRC]) != ops->addr_size)
 262                        goto errout;
 263
 264        if (frh->dst_len)
 265                if (tb[FRA_DST] == NULL ||
 266                    frh->dst_len > (ops->addr_size * 8) ||
 267                    nla_len(tb[FRA_DST]) != ops->addr_size)
 268                        goto errout;
 269
 270        err = 0;
 271errout:
 272        return err;
 273}
 274
 275static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 276{
 277        struct net *net = sock_net(skb->sk);
 278        struct fib_rule_hdr *frh = nlmsg_data(nlh);
 279        struct fib_rules_ops *ops = NULL;
 280        struct fib_rule *rule, *r, *last = NULL;
 281        struct nlattr *tb[FRA_MAX+1];
 282        int err = -EINVAL, unresolved = 0;
 283
 284        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 285                goto errout;
 286
 287        ops = lookup_rules_ops(net, frh->family);
 288        if (ops == NULL) {
 289                err = -EAFNOSUPPORT;
 290                goto errout;
 291        }
 292
 293        err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 294        if (err < 0)
 295                goto errout;
 296
 297        err = validate_rulemsg(frh, tb, ops);
 298        if (err < 0)
 299                goto errout;
 300
 301        rule = kzalloc(ops->rule_size, GFP_KERNEL);
 302        if (rule == NULL) {
 303                err = -ENOMEM;
 304                goto errout;
 305        }
 306        rule->fr_net = hold_net(net);
 307
 308        if (tb[FRA_PRIORITY])
 309                rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 310
 311        if (tb[FRA_IIFNAME]) {
 312                struct net_device *dev;
 313
 314                rule->iifindex = -1;
 315                nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 316                dev = __dev_get_by_name(net, rule->iifname);
 317                if (dev)
 318                        rule->iifindex = dev->ifindex;
 319        }
 320
 321        if (tb[FRA_OIFNAME]) {
 322                struct net_device *dev;
 323
 324                rule->oifindex = -1;
 325                nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 326                dev = __dev_get_by_name(net, rule->oifname);
 327                if (dev)
 328                        rule->oifindex = dev->ifindex;
 329        }
 330
 331        if (tb[FRA_FWMARK]) {
 332                rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 333                if (rule->mark)
 334                        /* compatibility: if the mark value is non-zero all bits
 335                         * are compared unless a mask is explicitly specified.
 336                         */
 337                        rule->mark_mask = 0xFFFFFFFF;
 338        }
 339
 340        if (tb[FRA_FWMASK])
 341                rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 342
 343        rule->action = frh->action;
 344        rule->flags = frh->flags;
 345        rule->table = frh_get_table(frh, tb);
 346        if (tb[FRA_SUPPRESS_PREFIXLEN])
 347                rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 348        else
 349                rule->suppress_prefixlen = -1;
 350
 351        if (tb[FRA_SUPPRESS_IFGROUP])
 352                rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 353        else
 354                rule->suppress_ifgroup = -1;
 355
 356        if (!tb[FRA_PRIORITY] && ops->default_pref)
 357                rule->pref = ops->default_pref(ops);
 358
 359        err = -EINVAL;
 360        if (tb[FRA_GOTO]) {
 361                if (rule->action != FR_ACT_GOTO)
 362                        goto errout_free;
 363
 364                rule->target = nla_get_u32(tb[FRA_GOTO]);
 365                /* Backward jumps are prohibited to avoid endless loops */
 366                if (rule->target <= rule->pref)
 367                        goto errout_free;
 368
 369                list_for_each_entry(r, &ops->rules_list, list) {
 370                        if (r->pref == rule->target) {
 371                                RCU_INIT_POINTER(rule->ctarget, r);
 372                                break;
 373                        }
 374                }
 375
 376                if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 377                        unresolved = 1;
 378        } else if (rule->action == FR_ACT_GOTO)
 379                goto errout_free;
 380
 381        err = ops->configure(rule, skb, frh, tb);
 382        if (err < 0)
 383                goto errout_free;
 384
 385        list_for_each_entry(r, &ops->rules_list, list) {
 386                if (r->pref > rule->pref)
 387                        break;
 388                last = r;
 389        }
 390
 391        fib_rule_get(rule);
 392
 393        if (last)
 394                list_add_rcu(&rule->list, &last->list);
 395        else
 396                list_add_rcu(&rule->list, &ops->rules_list);
 397
 398        if (ops->unresolved_rules) {
 399                /*
 400                 * There are unresolved goto rules in the list, check if
 401                 * any of them are pointing to this new rule.
 402                 */
 403                list_for_each_entry(r, &ops->rules_list, list) {
 404                        if (r->action == FR_ACT_GOTO &&
 405                            r->target == rule->pref &&
 406                            rtnl_dereference(r->ctarget) == NULL) {
 407                                rcu_assign_pointer(r->ctarget, rule);
 408                                if (--ops->unresolved_rules == 0)
 409                                        break;
 410                        }
 411                }
 412        }
 413
 414        if (rule->action == FR_ACT_GOTO)
 415                ops->nr_goto_rules++;
 416
 417        if (unresolved)
 418                ops->unresolved_rules++;
 419
 420        notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 421        flush_route_cache(ops);
 422        rules_ops_put(ops);
 423        return 0;
 424
 425errout_free:
 426        release_net(rule->fr_net);
 427        kfree(rule);
 428errout:
 429        rules_ops_put(ops);
 430        return err;
 431}
 432
 433static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 434{
 435        struct net *net = sock_net(skb->sk);
 436        struct fib_rule_hdr *frh = nlmsg_data(nlh);
 437        struct fib_rules_ops *ops = NULL;
 438        struct fib_rule *rule, *tmp;
 439        struct nlattr *tb[FRA_MAX+1];
 440        int err = -EINVAL;
 441
 442        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 443                goto errout;
 444
 445        ops = lookup_rules_ops(net, frh->family);
 446        if (ops == NULL) {
 447                err = -EAFNOSUPPORT;
 448                goto errout;
 449        }
 450
 451        err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 452        if (err < 0)
 453                goto errout;
 454
 455        err = validate_rulemsg(frh, tb, ops);
 456        if (err < 0)
 457                goto errout;
 458
 459        list_for_each_entry(rule, &ops->rules_list, list) {
 460                if (frh->action && (frh->action != rule->action))
 461                        continue;
 462
 463                if (frh_get_table(frh, tb) &&
 464                    (frh_get_table(frh, tb) != rule->table))
 465                        continue;
 466
 467                if (tb[FRA_PRIORITY] &&
 468                    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 469                        continue;
 470
 471                if (tb[FRA_IIFNAME] &&
 472                    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 473                        continue;
 474
 475                if (tb[FRA_OIFNAME] &&
 476                    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 477                        continue;
 478
 479                if (tb[FRA_FWMARK] &&
 480                    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 481                        continue;
 482
 483                if (tb[FRA_FWMASK] &&
 484                    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 485                        continue;
 486
 487                if (!ops->compare(rule, frh, tb))
 488                        continue;
 489
 490                if (rule->flags & FIB_RULE_PERMANENT) {
 491                        err = -EPERM;
 492                        goto errout;
 493                }
 494
 495                list_del_rcu(&rule->list);
 496
 497                if (rule->action == FR_ACT_GOTO) {
 498                        ops->nr_goto_rules--;
 499                        if (rtnl_dereference(rule->ctarget) == NULL)
 500                                ops->unresolved_rules--;
 501                }
 502
 503                /*
 504                 * Check if this rule is a target to any of them. If so,
 505                 * disable them. As this operation is eventually very
 506                 * expensive, it is only performed if goto rules have
 507                 * actually been added.
 508                 */
 509                if (ops->nr_goto_rules > 0) {
 510                        list_for_each_entry(tmp, &ops->rules_list, list) {
 511                                if (rtnl_dereference(tmp->ctarget) == rule) {
 512                                        RCU_INIT_POINTER(tmp->ctarget, NULL);
 513                                        ops->unresolved_rules++;
 514                                }
 515                        }
 516                }
 517
 518                notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 519                                   NETLINK_CB(skb).portid);
 520                if (ops->delete)
 521                        ops->delete(rule);
 522                fib_rule_put(rule);
 523                flush_route_cache(ops);
 524                rules_ops_put(ops);
 525                return 0;
 526        }
 527
 528        err = -ENOENT;
 529errout:
 530        rules_ops_put(ops);
 531        return err;
 532}
 533
 534static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 535                                         struct fib_rule *rule)
 536{
 537        size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 538                         + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 539                         + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 540                         + nla_total_size(4) /* FRA_PRIORITY */
 541                         + nla_total_size(4) /* FRA_TABLE */
 542                         + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 543                         + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 544                         + nla_total_size(4) /* FRA_FWMARK */
 545                         + nla_total_size(4); /* FRA_FWMASK */
 546
 547        if (ops->nlmsg_payload)
 548                payload += ops->nlmsg_payload(rule);
 549
 550        return payload;
 551}
 552
 553static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 554                            u32 pid, u32 seq, int type, int flags,
 555                            struct fib_rules_ops *ops)
 556{
 557        struct nlmsghdr *nlh;
 558        struct fib_rule_hdr *frh;
 559
 560        nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 561        if (nlh == NULL)
 562                return -EMSGSIZE;
 563
 564        frh = nlmsg_data(nlh);
 565        frh->family = ops->family;
 566        frh->table = rule->table;
 567        if (nla_put_u32(skb, FRA_TABLE, rule->table))
 568                goto nla_put_failure;
 569        if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 570                goto nla_put_failure;
 571        frh->res1 = 0;
 572        frh->res2 = 0;
 573        frh->action = rule->action;
 574        frh->flags = rule->flags;
 575
 576        if (rule->action == FR_ACT_GOTO &&
 577            rcu_access_pointer(rule->ctarget) == NULL)
 578                frh->flags |= FIB_RULE_UNRESOLVED;
 579
 580        if (rule->iifname[0]) {
 581                if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 582                        goto nla_put_failure;
 583                if (rule->iifindex == -1)
 584                        frh->flags |= FIB_RULE_IIF_DETACHED;
 585        }
 586
 587        if (rule->oifname[0]) {
 588                if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 589                        goto nla_put_failure;
 590                if (rule->oifindex == -1)
 591                        frh->flags |= FIB_RULE_OIF_DETACHED;
 592        }
 593
 594        if ((rule->pref &&
 595             nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 596            (rule->mark &&
 597             nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 598            ((rule->mark_mask || rule->mark) &&
 599             nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 600            (rule->target &&
 601             nla_put_u32(skb, FRA_GOTO, rule->target)))
 602                goto nla_put_failure;
 603
 604        if (rule->suppress_ifgroup != -1) {
 605                if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 606                        goto nla_put_failure;
 607        }
 608
 609        if (ops->fill(rule, skb, frh) < 0)
 610                goto nla_put_failure;
 611
 612        return nlmsg_end(skb, nlh);
 613
 614nla_put_failure:
 615        nlmsg_cancel(skb, nlh);
 616        return -EMSGSIZE;
 617}
 618
 619static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 620                      struct fib_rules_ops *ops)
 621{
 622        int idx = 0;
 623        struct fib_rule *rule;
 624
 625        rcu_read_lock();
 626        list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 627                if (idx < cb->args[1])
 628                        goto skip;
 629
 630                if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 631                                     cb->nlh->nlmsg_seq, RTM_NEWRULE,
 632                                     NLM_F_MULTI, ops) < 0)
 633                        break;
 634skip:
 635                idx++;
 636        }
 637        rcu_read_unlock();
 638        cb->args[1] = idx;
 639        rules_ops_put(ops);
 640
 641        return skb->len;
 642}
 643
 644static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 645{
 646        struct net *net = sock_net(skb->sk);
 647        struct fib_rules_ops *ops;
 648        int idx = 0, family;
 649
 650        family = rtnl_msg_family(cb->nlh);
 651        if (family != AF_UNSPEC) {
 652                /* Protocol specific dump request */
 653                ops = lookup_rules_ops(net, family);
 654                if (ops == NULL)
 655                        return -EAFNOSUPPORT;
 656
 657                return dump_rules(skb, cb, ops);
 658        }
 659
 660        rcu_read_lock();
 661        list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 662                if (idx < cb->args[0] || !try_module_get(ops->owner))
 663                        goto skip;
 664
 665                if (dump_rules(skb, cb, ops) < 0)
 666                        break;
 667
 668                cb->args[1] = 0;
 669skip:
 670                idx++;
 671        }
 672        rcu_read_unlock();
 673        cb->args[0] = idx;
 674
 675        return skb->len;
 676}
 677
 678static void notify_rule_change(int event, struct fib_rule *rule,
 679                               struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 680                               u32 pid)
 681{
 682        struct net *net;
 683        struct sk_buff *skb;
 684        int err = -ENOBUFS;
 685
 686        net = ops->fro_net;
 687        skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 688        if (skb == NULL)
 689                goto errout;
 690
 691        err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 692        if (err < 0) {
 693                /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 694                WARN_ON(err == -EMSGSIZE);
 695                kfree_skb(skb);
 696                goto errout;
 697        }
 698
 699        rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 700        return;
 701errout:
 702        if (err < 0)
 703                rtnl_set_sk_err(net, ops->nlgroup, err);
 704}
 705
 706static void attach_rules(struct list_head *rules, struct net_device *dev)
 707{
 708        struct fib_rule *rule;
 709
 710        list_for_each_entry(rule, rules, list) {
 711                if (rule->iifindex == -1 &&
 712                    strcmp(dev->name, rule->iifname) == 0)
 713                        rule->iifindex = dev->ifindex;
 714                if (rule->oifindex == -1 &&
 715                    strcmp(dev->name, rule->oifname) == 0)
 716                        rule->oifindex = dev->ifindex;
 717        }
 718}
 719
 720static void detach_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 == dev->ifindex)
 726                        rule->iifindex = -1;
 727                if (rule->oifindex == dev->ifindex)
 728                        rule->oifindex = -1;
 729        }
 730}
 731
 732
 733static int fib_rules_event(struct notifier_block *this, unsigned long event,
 734                           void *ptr)
 735{
 736        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 737        struct net *net = dev_net(dev);
 738        struct fib_rules_ops *ops;
 739
 740        ASSERT_RTNL();
 741
 742        switch (event) {
 743        case NETDEV_REGISTER:
 744                list_for_each_entry(ops, &net->rules_ops, list)
 745                        attach_rules(&ops->rules_list, dev);
 746                break;
 747
 748        case NETDEV_CHANGENAME:
 749                list_for_each_entry(ops, &net->rules_ops, list) {
 750                        detach_rules(&ops->rules_list, dev);
 751                        attach_rules(&ops->rules_list, dev);
 752                }
 753                break;
 754
 755        case NETDEV_UNREGISTER:
 756                list_for_each_entry(ops, &net->rules_ops, list)
 757                        detach_rules(&ops->rules_list, dev);
 758                break;
 759        }
 760
 761        return NOTIFY_DONE;
 762}
 763
 764static struct notifier_block fib_rules_notifier = {
 765        .notifier_call = fib_rules_event,
 766};
 767
 768static int __net_init fib_rules_net_init(struct net *net)
 769{
 770        INIT_LIST_HEAD(&net->rules_ops);
 771        spin_lock_init(&net->rules_mod_lock);
 772        return 0;
 773}
 774
 775static struct pernet_operations fib_rules_net_ops = {
 776        .init = fib_rules_net_init,
 777};
 778
 779static int __init fib_rules_init(void)
 780{
 781        int err;
 782        rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 783        rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 784        rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 785
 786        err = register_pernet_subsys(&fib_rules_net_ops);
 787        if (err < 0)
 788                goto fail;
 789
 790        err = register_netdevice_notifier(&fib_rules_notifier);
 791        if (err < 0)
 792                goto fail_unregister;
 793
 794        return 0;
 795
 796fail_unregister:
 797        unregister_pernet_subsys(&fib_rules_net_ops);
 798fail:
 799        rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 800        rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 801        rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 802        return err;
 803}
 804
 805subsys_initcall(fib_rules_init);
 806