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                          struct fib_lookup_arg *arg)
 178{
 179        int ret = 0;
 180
 181        if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
 182                goto out;
 183
 184        if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
 185                goto out;
 186
 187        if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
 188                goto out;
 189
 190        if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
 191                goto out;
 192
 193        if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
 194                goto out;
 195
 196        ret = ops->match(rule, fl, flags);
 197out:
 198        return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 199}
 200
 201int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
 202                     int flags, struct fib_lookup_arg *arg)
 203{
 204        struct fib_rule *rule;
 205        int err;
 206
 207        rcu_read_lock();
 208
 209        list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 210jumped:
 211                if (!fib_rule_match(rule, ops, fl, flags, arg))
 212                        continue;
 213
 214                if (rule->action == FR_ACT_GOTO) {
 215                        struct fib_rule *target;
 216
 217                        target = rcu_dereference(rule->ctarget);
 218                        if (target == NULL) {
 219                                continue;
 220                        } else {
 221                                rule = target;
 222                                goto jumped;
 223                        }
 224                } else if (rule->action == FR_ACT_NOP)
 225                        continue;
 226                else
 227                        err = ops->action(rule, fl, flags, arg);
 228
 229                if (!err && ops->suppress && ops->suppress(rule, arg))
 230                        continue;
 231
 232                if (err != -EAGAIN) {
 233                        if ((arg->flags & FIB_LOOKUP_NOREF) ||
 234                            likely(atomic_inc_not_zero(&rule->refcnt))) {
 235                                arg->rule = rule;
 236                                goto out;
 237                        }
 238                        break;
 239                }
 240        }
 241
 242        err = -ESRCH;
 243out:
 244        rcu_read_unlock();
 245
 246        return err;
 247}
 248EXPORT_SYMBOL_GPL(fib_rules_lookup);
 249
 250static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
 251                            struct fib_rules_ops *ops)
 252{
 253        int err = -EINVAL;
 254
 255        if (frh->src_len)
 256                if (tb[FRA_SRC] == NULL ||
 257                    frh->src_len > (ops->addr_size * 8) ||
 258                    nla_len(tb[FRA_SRC]) != ops->addr_size)
 259                        goto errout;
 260
 261        if (frh->dst_len)
 262                if (tb[FRA_DST] == NULL ||
 263                    frh->dst_len > (ops->addr_size * 8) ||
 264                    nla_len(tb[FRA_DST]) != ops->addr_size)
 265                        goto errout;
 266
 267        err = 0;
 268errout:
 269        return err;
 270}
 271
 272static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 273                       struct nlattr **tb, struct fib_rule *rule)
 274{
 275        struct fib_rule *r;
 276
 277        list_for_each_entry(r, &ops->rules_list, list) {
 278                if (r->action != rule->action)
 279                        continue;
 280
 281                if (r->table != rule->table)
 282                        continue;
 283
 284                if (r->pref != rule->pref)
 285                        continue;
 286
 287                if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 288                        continue;
 289
 290                if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 291                        continue;
 292
 293                if (r->mark != rule->mark)
 294                        continue;
 295
 296                if (r->mark_mask != rule->mark_mask)
 297                        continue;
 298
 299                if (r->tun_id != rule->tun_id)
 300                        continue;
 301
 302                if (r->fr_net != rule->fr_net)
 303                        continue;
 304
 305                if (r->l3mdev != rule->l3mdev)
 306                        continue;
 307
 308                if (!ops->compare(r, frh, tb))
 309                        continue;
 310                return 1;
 311        }
 312        return 0;
 313}
 314
 315int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh)
 316{
 317        struct net *net = sock_net(skb->sk);
 318        struct fib_rule_hdr *frh = nlmsg_data(nlh);
 319        struct fib_rules_ops *ops = NULL;
 320        struct fib_rule *rule, *r, *last = NULL;
 321        struct nlattr *tb[FRA_MAX+1];
 322        int err = -EINVAL, unresolved = 0;
 323
 324        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 325                goto errout;
 326
 327        ops = lookup_rules_ops(net, frh->family);
 328        if (ops == NULL) {
 329                err = -EAFNOSUPPORT;
 330                goto errout;
 331        }
 332
 333        err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 334        if (err < 0)
 335                goto errout;
 336
 337        err = validate_rulemsg(frh, tb, ops);
 338        if (err < 0)
 339                goto errout;
 340
 341        rule = kzalloc(ops->rule_size, GFP_KERNEL);
 342        if (rule == NULL) {
 343                err = -ENOMEM;
 344                goto errout;
 345        }
 346        rule->fr_net = net;
 347
 348        rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 349                                      : fib_default_rule_pref(ops);
 350
 351        if (tb[FRA_IIFNAME]) {
 352                struct net_device *dev;
 353
 354                rule->iifindex = -1;
 355                nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 356                dev = __dev_get_by_name(net, rule->iifname);
 357                if (dev)
 358                        rule->iifindex = dev->ifindex;
 359        }
 360
 361        if (tb[FRA_OIFNAME]) {
 362                struct net_device *dev;
 363
 364                rule->oifindex = -1;
 365                nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 366                dev = __dev_get_by_name(net, rule->oifname);
 367                if (dev)
 368                        rule->oifindex = dev->ifindex;
 369        }
 370
 371        if (tb[FRA_FWMARK]) {
 372                rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 373                if (rule->mark)
 374                        /* compatibility: if the mark value is non-zero all bits
 375                         * are compared unless a mask is explicitly specified.
 376                         */
 377                        rule->mark_mask = 0xFFFFFFFF;
 378        }
 379
 380        if (tb[FRA_FWMASK])
 381                rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 382
 383        if (tb[FRA_TUN_ID])
 384                rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 385
 386        if (tb[FRA_L3MDEV]) {
 387#ifdef CONFIG_NET_L3_MASTER_DEV
 388                rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
 389                if (rule->l3mdev != 1)
 390#endif
 391                        goto errout_free;
 392        }
 393
 394        rule->action = frh->action;
 395        rule->flags = frh->flags;
 396        rule->table = frh_get_table(frh, tb);
 397        if (tb[FRA_SUPPRESS_PREFIXLEN])
 398                rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 399        else
 400                rule->suppress_prefixlen = -1;
 401
 402        if (tb[FRA_SUPPRESS_IFGROUP])
 403                rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 404        else
 405                rule->suppress_ifgroup = -1;
 406
 407        err = -EINVAL;
 408        if (tb[FRA_GOTO]) {
 409                if (rule->action != FR_ACT_GOTO)
 410                        goto errout_free;
 411
 412                rule->target = nla_get_u32(tb[FRA_GOTO]);
 413                /* Backward jumps are prohibited to avoid endless loops */
 414                if (rule->target <= rule->pref)
 415                        goto errout_free;
 416
 417                list_for_each_entry(r, &ops->rules_list, list) {
 418                        if (r->pref == rule->target) {
 419                                RCU_INIT_POINTER(rule->ctarget, r);
 420                                break;
 421                        }
 422                }
 423
 424                if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 425                        unresolved = 1;
 426        } else if (rule->action == FR_ACT_GOTO)
 427                goto errout_free;
 428
 429        if (rule->l3mdev && rule->table)
 430                goto errout_free;
 431
 432        if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 433            rule_exists(ops, frh, tb, rule)) {
 434                err = -EEXIST;
 435                goto errout_free;
 436        }
 437
 438        err = ops->configure(rule, skb, frh, tb);
 439        if (err < 0)
 440                goto errout_free;
 441
 442        list_for_each_entry(r, &ops->rules_list, list) {
 443                if (r->pref > rule->pref)
 444                        break;
 445                last = r;
 446        }
 447
 448        fib_rule_get(rule);
 449
 450        if (last)
 451                list_add_rcu(&rule->list, &last->list);
 452        else
 453                list_add_rcu(&rule->list, &ops->rules_list);
 454
 455        if (ops->unresolved_rules) {
 456                /*
 457                 * There are unresolved goto rules in the list, check if
 458                 * any of them are pointing to this new rule.
 459                 */
 460                list_for_each_entry(r, &ops->rules_list, list) {
 461                        if (r->action == FR_ACT_GOTO &&
 462                            r->target == rule->pref &&
 463                            rtnl_dereference(r->ctarget) == NULL) {
 464                                rcu_assign_pointer(r->ctarget, rule);
 465                                if (--ops->unresolved_rules == 0)
 466                                        break;
 467                        }
 468                }
 469        }
 470
 471        if (rule->action == FR_ACT_GOTO)
 472                ops->nr_goto_rules++;
 473
 474        if (unresolved)
 475                ops->unresolved_rules++;
 476
 477        if (rule->tun_id)
 478                ip_tunnel_need_metadata();
 479
 480        notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 481        flush_route_cache(ops);
 482        rules_ops_put(ops);
 483        return 0;
 484
 485errout_free:
 486        kfree(rule);
 487errout:
 488        rules_ops_put(ops);
 489        return err;
 490}
 491EXPORT_SYMBOL_GPL(fib_nl_newrule);
 492
 493int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh)
 494{
 495        struct net *net = sock_net(skb->sk);
 496        struct fib_rule_hdr *frh = nlmsg_data(nlh);
 497        struct fib_rules_ops *ops = NULL;
 498        struct fib_rule *rule, *tmp;
 499        struct nlattr *tb[FRA_MAX+1];
 500        int err = -EINVAL;
 501
 502        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 503                goto errout;
 504
 505        ops = lookup_rules_ops(net, frh->family);
 506        if (ops == NULL) {
 507                err = -EAFNOSUPPORT;
 508                goto errout;
 509        }
 510
 511        err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
 512        if (err < 0)
 513                goto errout;
 514
 515        err = validate_rulemsg(frh, tb, ops);
 516        if (err < 0)
 517                goto errout;
 518
 519        list_for_each_entry(rule, &ops->rules_list, list) {
 520                if (frh->action && (frh->action != rule->action))
 521                        continue;
 522
 523                if (frh_get_table(frh, tb) &&
 524                    (frh_get_table(frh, tb) != rule->table))
 525                        continue;
 526
 527                if (tb[FRA_PRIORITY] &&
 528                    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 529                        continue;
 530
 531                if (tb[FRA_IIFNAME] &&
 532                    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 533                        continue;
 534
 535                if (tb[FRA_OIFNAME] &&
 536                    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 537                        continue;
 538
 539                if (tb[FRA_FWMARK] &&
 540                    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 541                        continue;
 542
 543                if (tb[FRA_FWMASK] &&
 544                    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 545                        continue;
 546
 547                if (tb[FRA_TUN_ID] &&
 548                    (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
 549                        continue;
 550
 551                if (tb[FRA_L3MDEV] &&
 552                    (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
 553                        continue;
 554
 555                if (!ops->compare(rule, frh, tb))
 556                        continue;
 557
 558                if (rule->flags & FIB_RULE_PERMANENT) {
 559                        err = -EPERM;
 560                        goto errout;
 561                }
 562
 563                if (ops->delete) {
 564                        err = ops->delete(rule);
 565                        if (err)
 566                                goto errout;
 567                }
 568
 569                if (rule->tun_id)
 570                        ip_tunnel_unneed_metadata();
 571
 572                list_del_rcu(&rule->list);
 573
 574                if (rule->action == FR_ACT_GOTO) {
 575                        ops->nr_goto_rules--;
 576                        if (rtnl_dereference(rule->ctarget) == NULL)
 577                                ops->unresolved_rules--;
 578                }
 579
 580                /*
 581                 * Check if this rule is a target to any of them. If so,
 582                 * disable them. As this operation is eventually very
 583                 * expensive, it is only performed if goto rules have
 584                 * actually been added.
 585                 */
 586                if (ops->nr_goto_rules > 0) {
 587                        list_for_each_entry(tmp, &ops->rules_list, list) {
 588                                if (rtnl_dereference(tmp->ctarget) == rule) {
 589                                        RCU_INIT_POINTER(tmp->ctarget, NULL);
 590                                        ops->unresolved_rules++;
 591                                }
 592                        }
 593                }
 594
 595                notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 596                                   NETLINK_CB(skb).portid);
 597                fib_rule_put(rule);
 598                flush_route_cache(ops);
 599                rules_ops_put(ops);
 600                return 0;
 601        }
 602
 603        err = -ENOENT;
 604errout:
 605        rules_ops_put(ops);
 606        return err;
 607}
 608EXPORT_SYMBOL_GPL(fib_nl_delrule);
 609
 610static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 611                                         struct fib_rule *rule)
 612{
 613        size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 614                         + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 615                         + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 616                         + nla_total_size(4) /* FRA_PRIORITY */
 617                         + nla_total_size(4) /* FRA_TABLE */
 618                         + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 619                         + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 620                         + nla_total_size(4) /* FRA_FWMARK */
 621                         + nla_total_size(4) /* FRA_FWMASK */
 622                         + nla_total_size_64bit(8); /* FRA_TUN_ID */
 623
 624        if (ops->nlmsg_payload)
 625                payload += ops->nlmsg_payload(rule);
 626
 627        return payload;
 628}
 629
 630static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 631                            u32 pid, u32 seq, int type, int flags,
 632                            struct fib_rules_ops *ops)
 633{
 634        struct nlmsghdr *nlh;
 635        struct fib_rule_hdr *frh;
 636
 637        nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 638        if (nlh == NULL)
 639                return -EMSGSIZE;
 640
 641        frh = nlmsg_data(nlh);
 642        frh->family = ops->family;
 643        frh->table = rule->table;
 644        if (nla_put_u32(skb, FRA_TABLE, rule->table))
 645                goto nla_put_failure;
 646        if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 647                goto nla_put_failure;
 648        frh->res1 = 0;
 649        frh->res2 = 0;
 650        frh->action = rule->action;
 651        frh->flags = rule->flags;
 652
 653        if (rule->action == FR_ACT_GOTO &&
 654            rcu_access_pointer(rule->ctarget) == NULL)
 655                frh->flags |= FIB_RULE_UNRESOLVED;
 656
 657        if (rule->iifname[0]) {
 658                if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 659                        goto nla_put_failure;
 660                if (rule->iifindex == -1)
 661                        frh->flags |= FIB_RULE_IIF_DETACHED;
 662        }
 663
 664        if (rule->oifname[0]) {
 665                if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 666                        goto nla_put_failure;
 667                if (rule->oifindex == -1)
 668                        frh->flags |= FIB_RULE_OIF_DETACHED;
 669        }
 670
 671        if ((rule->pref &&
 672             nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 673            (rule->mark &&
 674             nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 675            ((rule->mark_mask || rule->mark) &&
 676             nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 677            (rule->target &&
 678             nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 679            (rule->tun_id &&
 680             nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 681            (rule->l3mdev &&
 682             nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)))
 683                goto nla_put_failure;
 684
 685        if (rule->suppress_ifgroup != -1) {
 686                if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 687                        goto nla_put_failure;
 688        }
 689
 690        if (ops->fill(rule, skb, frh) < 0)
 691                goto nla_put_failure;
 692
 693        nlmsg_end(skb, nlh);
 694        return 0;
 695
 696nla_put_failure:
 697        nlmsg_cancel(skb, nlh);
 698        return -EMSGSIZE;
 699}
 700
 701static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 702                      struct fib_rules_ops *ops)
 703{
 704        int idx = 0;
 705        struct fib_rule *rule;
 706        int err = 0;
 707
 708        rcu_read_lock();
 709        list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 710                if (idx < cb->args[1])
 711                        goto skip;
 712
 713                err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 714                                       cb->nlh->nlmsg_seq, RTM_NEWRULE,
 715                                       NLM_F_MULTI, ops);
 716                if (err)
 717                        break;
 718skip:
 719                idx++;
 720        }
 721        rcu_read_unlock();
 722        cb->args[1] = idx;
 723        rules_ops_put(ops);
 724
 725        return err;
 726}
 727
 728static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 729{
 730        struct net *net = sock_net(skb->sk);
 731        struct fib_rules_ops *ops;
 732        int idx = 0, family;
 733
 734        family = rtnl_msg_family(cb->nlh);
 735        if (family != AF_UNSPEC) {
 736                /* Protocol specific dump request */
 737                ops = lookup_rules_ops(net, family);
 738                if (ops == NULL)
 739                        return -EAFNOSUPPORT;
 740
 741                dump_rules(skb, cb, ops);
 742
 743                return skb->len;
 744        }
 745
 746        rcu_read_lock();
 747        list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 748                if (idx < cb->args[0] || !try_module_get(ops->owner))
 749                        goto skip;
 750
 751                if (dump_rules(skb, cb, ops) < 0)
 752                        break;
 753
 754                cb->args[1] = 0;
 755skip:
 756                idx++;
 757        }
 758        rcu_read_unlock();
 759        cb->args[0] = idx;
 760
 761        return skb->len;
 762}
 763
 764static void notify_rule_change(int event, struct fib_rule *rule,
 765                               struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 766                               u32 pid)
 767{
 768        struct net *net;
 769        struct sk_buff *skb;
 770        int err = -ENOBUFS;
 771
 772        net = ops->fro_net;
 773        skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 774        if (skb == NULL)
 775                goto errout;
 776
 777        err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 778        if (err < 0) {
 779                /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 780                WARN_ON(err == -EMSGSIZE);
 781                kfree_skb(skb);
 782                goto errout;
 783        }
 784
 785        rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 786        return;
 787errout:
 788        if (err < 0)
 789                rtnl_set_sk_err(net, ops->nlgroup, err);
 790}
 791
 792static void attach_rules(struct list_head *rules, struct net_device *dev)
 793{
 794        struct fib_rule *rule;
 795
 796        list_for_each_entry(rule, rules, list) {
 797                if (rule->iifindex == -1 &&
 798                    strcmp(dev->name, rule->iifname) == 0)
 799                        rule->iifindex = dev->ifindex;
 800                if (rule->oifindex == -1 &&
 801                    strcmp(dev->name, rule->oifname) == 0)
 802                        rule->oifindex = dev->ifindex;
 803        }
 804}
 805
 806static void detach_rules(struct list_head *rules, struct net_device *dev)
 807{
 808        struct fib_rule *rule;
 809
 810        list_for_each_entry(rule, rules, list) {
 811                if (rule->iifindex == dev->ifindex)
 812                        rule->iifindex = -1;
 813                if (rule->oifindex == dev->ifindex)
 814                        rule->oifindex = -1;
 815        }
 816}
 817
 818
 819static int fib_rules_event(struct notifier_block *this, unsigned long event,
 820                           void *ptr)
 821{
 822        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 823        struct net *net = dev_net(dev);
 824        struct fib_rules_ops *ops;
 825
 826        ASSERT_RTNL();
 827
 828        switch (event) {
 829        case NETDEV_REGISTER:
 830                list_for_each_entry(ops, &net->rules_ops, list)
 831                        attach_rules(&ops->rules_list, dev);
 832                break;
 833
 834        case NETDEV_CHANGENAME:
 835                list_for_each_entry(ops, &net->rules_ops, list) {
 836                        detach_rules(&ops->rules_list, dev);
 837                        attach_rules(&ops->rules_list, dev);
 838                }
 839                break;
 840
 841        case NETDEV_UNREGISTER:
 842                list_for_each_entry(ops, &net->rules_ops, list)
 843                        detach_rules(&ops->rules_list, dev);
 844                break;
 845        }
 846
 847        return NOTIFY_DONE;
 848}
 849
 850static struct notifier_block fib_rules_notifier = {
 851        .notifier_call = fib_rules_event,
 852};
 853
 854static int __net_init fib_rules_net_init(struct net *net)
 855{
 856        INIT_LIST_HEAD(&net->rules_ops);
 857        spin_lock_init(&net->rules_mod_lock);
 858        return 0;
 859}
 860
 861static struct pernet_operations fib_rules_net_ops = {
 862        .init = fib_rules_net_init,
 863};
 864
 865static int __init fib_rules_init(void)
 866{
 867        int err;
 868        rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 869        rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 870        rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 871
 872        err = register_pernet_subsys(&fib_rules_net_ops);
 873        if (err < 0)
 874                goto fail;
 875
 876        err = register_netdevice_notifier(&fib_rules_notifier);
 877        if (err < 0)
 878                goto fail_unregister;
 879
 880        return 0;
 881
 882fail_unregister:
 883        unregister_pernet_subsys(&fib_rules_net_ops);
 884fail:
 885        rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 886        rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 887        rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 888        return err;
 889}
 890
 891subsys_initcall(fib_rules_init);
 892