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
  21static const struct fib_kuid_range fib_kuid_range_unset = {
  22        KUIDT_INIT(0),
  23        KUIDT_INIT(~0),
  24};
  25
  26bool 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}
  38EXPORT_SYMBOL_GPL(fib_rule_matchall);
  39
  40int 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}
  65EXPORT_SYMBOL(fib_default_rule_add);
  66
  67static 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
  84static void notify_rule_change(int event, struct fib_rule *rule,
  85                               struct fib_rules_ops *ops, struct nlmsghdr *nlh,
  86                               u32 pid);
  87
  88static 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
 106static void rules_ops_put(struct fib_rules_ops *ops)
 107{
 108        if (ops)
 109                module_put(ops->owner);
 110}
 111
 112static void flush_route_cache(struct fib_rules_ops *ops)
 113{
 114        if (ops->flush_cache)
 115                ops->flush_cache(ops);
 116}
 117
 118static 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;
 141errout:
 142        spin_unlock(&net->rules_mod_lock);
 143
 144        return err;
 145}
 146
 147struct fib_rules_ops *
 148fib_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}
 168EXPORT_SYMBOL_GPL(fib_rules_register);
 169
 170static 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
 182void 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}
 193EXPORT_SYMBOL_GPL(fib_rules_unregister);
 194
 195static int uid_range_set(struct fib_kuid_range *range)
 196{
 197        return uid_valid(range->start) && uid_valid(range->end);
 198}
 199
 200static 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
 213static 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
 223static 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);
 249out:
 250        return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
 251}
 252
 253int 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) {
 262jumped:
 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;
 295out:
 296        rcu_read_unlock();
 297
 298        return err;
 299}
 300EXPORT_SYMBOL_GPL(fib_rules_lookup);
 301
 302static 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;
 320errout:
 321        return err;
 322}
 323
 324static 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
 371int 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        refcount_set(&rule->refcnt, 1);
 404        rule->fr_net = net;
 405
 406        rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 407                                      : fib_default_rule_pref(ops);
 408
 409        if (tb[FRA_IIFNAME]) {
 410                struct net_device *dev;
 411
 412                rule->iifindex = -1;
 413                nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 414                dev = __dev_get_by_name(net, rule->iifname);
 415                if (dev)
 416                        rule->iifindex = dev->ifindex;
 417        }
 418
 419        if (tb[FRA_OIFNAME]) {
 420                struct net_device *dev;
 421
 422                rule->oifindex = -1;
 423                nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 424                dev = __dev_get_by_name(net, rule->oifname);
 425                if (dev)
 426                        rule->oifindex = dev->ifindex;
 427        }
 428
 429        if (tb[FRA_FWMARK]) {
 430                rule->mark = nla_get_u32(tb[FRA_FWMARK]);
 431                if (rule->mark)
 432                        /* compatibility: if the mark value is non-zero all bits
 433                         * are compared unless a mask is explicitly specified.
 434                         */
 435                        rule->mark_mask = 0xFFFFFFFF;
 436        }
 437
 438        if (tb[FRA_FWMASK])
 439                rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 440
 441        if (tb[FRA_TUN_ID])
 442                rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 443
 444        err = -EINVAL;
 445        if (tb[FRA_L3MDEV]) {
 446#ifdef CONFIG_NET_L3_MASTER_DEV
 447                rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
 448                if (rule->l3mdev != 1)
 449#endif
 450                        goto errout_free;
 451        }
 452
 453        rule->action = frh->action;
 454        rule->flags = frh->flags;
 455        rule->table = frh_get_table(frh, tb);
 456        if (tb[FRA_SUPPRESS_PREFIXLEN])
 457                rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 458        else
 459                rule->suppress_prefixlen = -1;
 460
 461        if (tb[FRA_SUPPRESS_IFGROUP])
 462                rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 463        else
 464                rule->suppress_ifgroup = -1;
 465
 466        if (tb[FRA_GOTO]) {
 467                if (rule->action != FR_ACT_GOTO)
 468                        goto errout_free;
 469
 470                rule->target = nla_get_u32(tb[FRA_GOTO]);
 471                /* Backward jumps are prohibited to avoid endless loops */
 472                if (rule->target <= rule->pref)
 473                        goto errout_free;
 474
 475                list_for_each_entry(r, &ops->rules_list, list) {
 476                        if (r->pref == rule->target) {
 477                                RCU_INIT_POINTER(rule->ctarget, r);
 478                                break;
 479                        }
 480                }
 481
 482                if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 483                        unresolved = 1;
 484        } else if (rule->action == FR_ACT_GOTO)
 485                goto errout_free;
 486
 487        if (rule->l3mdev && rule->table)
 488                goto errout_free;
 489
 490        if (tb[FRA_UID_RANGE]) {
 491                if (current_user_ns() != net->user_ns) {
 492                        err = -EPERM;
 493                        goto errout_free;
 494                }
 495
 496                rule->uid_range = nla_get_kuid_range(tb);
 497
 498                if (!uid_range_set(&rule->uid_range) ||
 499                    !uid_lte(rule->uid_range.start, rule->uid_range.end))
 500                        goto errout_free;
 501        } else {
 502                rule->uid_range = fib_kuid_range_unset;
 503        }
 504
 505        if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 506            rule_exists(ops, frh, tb, rule)) {
 507                err = -EEXIST;
 508                goto errout_free;
 509        }
 510
 511        err = ops->configure(rule, skb, frh, tb);
 512        if (err < 0)
 513                goto errout_free;
 514
 515        list_for_each_entry(r, &ops->rules_list, list) {
 516                if (r->pref > rule->pref)
 517                        break;
 518                last = r;
 519        }
 520
 521        if (last)
 522                list_add_rcu(&rule->list, &last->list);
 523        else
 524                list_add_rcu(&rule->list, &ops->rules_list);
 525
 526        if (ops->unresolved_rules) {
 527                /*
 528                 * There are unresolved goto rules in the list, check if
 529                 * any of them are pointing to this new rule.
 530                 */
 531                list_for_each_entry(r, &ops->rules_list, list) {
 532                        if (r->action == FR_ACT_GOTO &&
 533                            r->target == rule->pref &&
 534                            rtnl_dereference(r->ctarget) == NULL) {
 535                                rcu_assign_pointer(r->ctarget, rule);
 536                                if (--ops->unresolved_rules == 0)
 537                                        break;
 538                        }
 539                }
 540        }
 541
 542        if (rule->action == FR_ACT_GOTO)
 543                ops->nr_goto_rules++;
 544
 545        if (unresolved)
 546                ops->unresolved_rules++;
 547
 548        if (rule->tun_id)
 549                ip_tunnel_need_metadata();
 550
 551        notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 552        flush_route_cache(ops);
 553        rules_ops_put(ops);
 554        return 0;
 555
 556errout_free:
 557        kfree(rule);
 558errout:
 559        rules_ops_put(ops);
 560        return err;
 561}
 562EXPORT_SYMBOL_GPL(fib_nl_newrule);
 563
 564int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 565                   struct netlink_ext_ack *extack)
 566{
 567        struct net *net = sock_net(skb->sk);
 568        struct fib_rule_hdr *frh = nlmsg_data(nlh);
 569        struct fib_rules_ops *ops = NULL;
 570        struct fib_rule *rule, *r;
 571        struct nlattr *tb[FRA_MAX+1];
 572        struct fib_kuid_range range;
 573        int err = -EINVAL;
 574
 575        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 576                goto errout;
 577
 578        ops = lookup_rules_ops(net, frh->family);
 579        if (ops == NULL) {
 580                err = -EAFNOSUPPORT;
 581                goto errout;
 582        }
 583
 584        err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
 585        if (err < 0)
 586                goto errout;
 587
 588        err = validate_rulemsg(frh, tb, ops);
 589        if (err < 0)
 590                goto errout;
 591
 592        if (tb[FRA_UID_RANGE]) {
 593                range = nla_get_kuid_range(tb);
 594                if (!uid_range_set(&range)) {
 595                        err = -EINVAL;
 596                        goto errout;
 597                }
 598        } else {
 599                range = fib_kuid_range_unset;
 600        }
 601
 602        list_for_each_entry(rule, &ops->rules_list, list) {
 603                if (frh->action && (frh->action != rule->action))
 604                        continue;
 605
 606                if (frh_get_table(frh, tb) &&
 607                    (frh_get_table(frh, tb) != rule->table))
 608                        continue;
 609
 610                if (tb[FRA_PRIORITY] &&
 611                    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
 612                        continue;
 613
 614                if (tb[FRA_IIFNAME] &&
 615                    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
 616                        continue;
 617
 618                if (tb[FRA_OIFNAME] &&
 619                    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
 620                        continue;
 621
 622                if (tb[FRA_FWMARK] &&
 623                    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
 624                        continue;
 625
 626                if (tb[FRA_FWMASK] &&
 627                    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
 628                        continue;
 629
 630                if (tb[FRA_TUN_ID] &&
 631                    (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
 632                        continue;
 633
 634                if (tb[FRA_L3MDEV] &&
 635                    (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
 636                        continue;
 637
 638                if (uid_range_set(&range) &&
 639                    (!uid_eq(rule->uid_range.start, range.start) ||
 640                     !uid_eq(rule->uid_range.end, range.end)))
 641                        continue;
 642
 643                if (!ops->compare(rule, frh, tb))
 644                        continue;
 645
 646                if (rule->flags & FIB_RULE_PERMANENT) {
 647                        err = -EPERM;
 648                        goto errout;
 649                }
 650
 651                if (ops->delete) {
 652                        err = ops->delete(rule);
 653                        if (err)
 654                                goto errout;
 655                }
 656
 657                if (rule->tun_id)
 658                        ip_tunnel_unneed_metadata();
 659
 660                list_del_rcu(&rule->list);
 661
 662                if (rule->action == FR_ACT_GOTO) {
 663                        ops->nr_goto_rules--;
 664                        if (rtnl_dereference(rule->ctarget) == NULL)
 665                                ops->unresolved_rules--;
 666                }
 667
 668                /*
 669                 * Check if this rule is a target to any of them. If so,
 670                 * adjust to the next one with the same preference or
 671                 * disable them. As this operation is eventually very
 672                 * expensive, it is only performed if goto rules, except
 673                 * current if it is goto rule, have actually been added.
 674                 */
 675                if (ops->nr_goto_rules > 0) {
 676                        struct fib_rule *n;
 677
 678                        n = list_next_entry(rule, list);
 679                        if (&n->list == &ops->rules_list || n->pref != rule->pref)
 680                                n = NULL;
 681                        list_for_each_entry(r, &ops->rules_list, list) {
 682                                if (rtnl_dereference(r->ctarget) != rule)
 683                                        continue;
 684                                rcu_assign_pointer(r->ctarget, n);
 685                                if (!n)
 686                                        ops->unresolved_rules++;
 687                        }
 688                }
 689
 690                notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 691                                   NETLINK_CB(skb).portid);
 692                fib_rule_put(rule);
 693                flush_route_cache(ops);
 694                rules_ops_put(ops);
 695                return 0;
 696        }
 697
 698        err = -ENOENT;
 699errout:
 700        rules_ops_put(ops);
 701        return err;
 702}
 703EXPORT_SYMBOL_GPL(fib_nl_delrule);
 704
 705static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 706                                         struct fib_rule *rule)
 707{
 708        size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 709                         + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 710                         + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 711                         + nla_total_size(4) /* FRA_PRIORITY */
 712                         + nla_total_size(4) /* FRA_TABLE */
 713                         + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 714                         + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 715                         + nla_total_size(4) /* FRA_FWMARK */
 716                         + nla_total_size(4) /* FRA_FWMASK */
 717                         + nla_total_size_64bit(8) /* FRA_TUN_ID */
 718                         + nla_total_size(sizeof(struct fib_kuid_range));
 719
 720        if (ops->nlmsg_payload)
 721                payload += ops->nlmsg_payload(rule);
 722
 723        return payload;
 724}
 725
 726static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 727                            u32 pid, u32 seq, int type, int flags,
 728                            struct fib_rules_ops *ops)
 729{
 730        struct nlmsghdr *nlh;
 731        struct fib_rule_hdr *frh;
 732
 733        nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 734        if (nlh == NULL)
 735                return -EMSGSIZE;
 736
 737        frh = nlmsg_data(nlh);
 738        frh->family = ops->family;
 739        frh->table = rule->table;
 740        if (nla_put_u32(skb, FRA_TABLE, rule->table))
 741                goto nla_put_failure;
 742        if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 743                goto nla_put_failure;
 744        frh->res1 = 0;
 745        frh->res2 = 0;
 746        frh->action = rule->action;
 747        frh->flags = rule->flags;
 748
 749        if (rule->action == FR_ACT_GOTO &&
 750            rcu_access_pointer(rule->ctarget) == NULL)
 751                frh->flags |= FIB_RULE_UNRESOLVED;
 752
 753        if (rule->iifname[0]) {
 754                if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 755                        goto nla_put_failure;
 756                if (rule->iifindex == -1)
 757                        frh->flags |= FIB_RULE_IIF_DETACHED;
 758        }
 759
 760        if (rule->oifname[0]) {
 761                if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 762                        goto nla_put_failure;
 763                if (rule->oifindex == -1)
 764                        frh->flags |= FIB_RULE_OIF_DETACHED;
 765        }
 766
 767        if ((rule->pref &&
 768             nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
 769            (rule->mark &&
 770             nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
 771            ((rule->mark_mask || rule->mark) &&
 772             nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
 773            (rule->target &&
 774             nla_put_u32(skb, FRA_GOTO, rule->target)) ||
 775            (rule->tun_id &&
 776             nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
 777            (rule->l3mdev &&
 778             nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
 779            (uid_range_set(&rule->uid_range) &&
 780             nla_put_uid_range(skb, &rule->uid_range)))
 781                goto nla_put_failure;
 782
 783        if (rule->suppress_ifgroup != -1) {
 784                if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
 785                        goto nla_put_failure;
 786        }
 787
 788        if (ops->fill(rule, skb, frh) < 0)
 789                goto nla_put_failure;
 790
 791        nlmsg_end(skb, nlh);
 792        return 0;
 793
 794nla_put_failure:
 795        nlmsg_cancel(skb, nlh);
 796        return -EMSGSIZE;
 797}
 798
 799static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
 800                      struct fib_rules_ops *ops)
 801{
 802        int idx = 0;
 803        struct fib_rule *rule;
 804        int err = 0;
 805
 806        rcu_read_lock();
 807        list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 808                if (idx < cb->args[1])
 809                        goto skip;
 810
 811                err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
 812                                       cb->nlh->nlmsg_seq, RTM_NEWRULE,
 813                                       NLM_F_MULTI, ops);
 814                if (err)
 815                        break;
 816skip:
 817                idx++;
 818        }
 819        rcu_read_unlock();
 820        cb->args[1] = idx;
 821        rules_ops_put(ops);
 822
 823        return err;
 824}
 825
 826static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
 827{
 828        struct net *net = sock_net(skb->sk);
 829        struct fib_rules_ops *ops;
 830        int idx = 0, family;
 831
 832        family = rtnl_msg_family(cb->nlh);
 833        if (family != AF_UNSPEC) {
 834                /* Protocol specific dump request */
 835                ops = lookup_rules_ops(net, family);
 836                if (ops == NULL)
 837                        return -EAFNOSUPPORT;
 838
 839                dump_rules(skb, cb, ops);
 840
 841                return skb->len;
 842        }
 843
 844        rcu_read_lock();
 845        list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 846                if (idx < cb->args[0] || !try_module_get(ops->owner))
 847                        goto skip;
 848
 849                if (dump_rules(skb, cb, ops) < 0)
 850                        break;
 851
 852                cb->args[1] = 0;
 853skip:
 854                idx++;
 855        }
 856        rcu_read_unlock();
 857        cb->args[0] = idx;
 858
 859        return skb->len;
 860}
 861
 862static void notify_rule_change(int event, struct fib_rule *rule,
 863                               struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 864                               u32 pid)
 865{
 866        struct net *net;
 867        struct sk_buff *skb;
 868        int err = -ENOBUFS;
 869
 870        net = ops->fro_net;
 871        skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
 872        if (skb == NULL)
 873                goto errout;
 874
 875        err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
 876        if (err < 0) {
 877                /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
 878                WARN_ON(err == -EMSGSIZE);
 879                kfree_skb(skb);
 880                goto errout;
 881        }
 882
 883        rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
 884        return;
 885errout:
 886        if (err < 0)
 887                rtnl_set_sk_err(net, ops->nlgroup, err);
 888}
 889
 890static void attach_rules(struct list_head *rules, struct net_device *dev)
 891{
 892        struct fib_rule *rule;
 893
 894        list_for_each_entry(rule, rules, list) {
 895                if (rule->iifindex == -1 &&
 896                    strcmp(dev->name, rule->iifname) == 0)
 897                        rule->iifindex = dev->ifindex;
 898                if (rule->oifindex == -1 &&
 899                    strcmp(dev->name, rule->oifname) == 0)
 900                        rule->oifindex = dev->ifindex;
 901        }
 902}
 903
 904static void detach_rules(struct list_head *rules, struct net_device *dev)
 905{
 906        struct fib_rule *rule;
 907
 908        list_for_each_entry(rule, rules, list) {
 909                if (rule->iifindex == dev->ifindex)
 910                        rule->iifindex = -1;
 911                if (rule->oifindex == dev->ifindex)
 912                        rule->oifindex = -1;
 913        }
 914}
 915
 916
 917static int fib_rules_event(struct notifier_block *this, unsigned long event,
 918                           void *ptr)
 919{
 920        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 921        struct net *net = dev_net(dev);
 922        struct fib_rules_ops *ops;
 923
 924        ASSERT_RTNL();
 925
 926        switch (event) {
 927        case NETDEV_REGISTER:
 928                list_for_each_entry(ops, &net->rules_ops, list)
 929                        attach_rules(&ops->rules_list, dev);
 930                break;
 931
 932        case NETDEV_CHANGENAME:
 933                list_for_each_entry(ops, &net->rules_ops, list) {
 934                        detach_rules(&ops->rules_list, dev);
 935                        attach_rules(&ops->rules_list, dev);
 936                }
 937                break;
 938
 939        case NETDEV_UNREGISTER:
 940                list_for_each_entry(ops, &net->rules_ops, list)
 941                        detach_rules(&ops->rules_list, dev);
 942                break;
 943        }
 944
 945        return NOTIFY_DONE;
 946}
 947
 948static struct notifier_block fib_rules_notifier = {
 949        .notifier_call = fib_rules_event,
 950};
 951
 952static int __net_init fib_rules_net_init(struct net *net)
 953{
 954        INIT_LIST_HEAD(&net->rules_ops);
 955        spin_lock_init(&net->rules_mod_lock);
 956        return 0;
 957}
 958
 959static struct pernet_operations fib_rules_net_ops = {
 960        .init = fib_rules_net_init,
 961};
 962
 963static int __init fib_rules_init(void)
 964{
 965        int err;
 966        rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
 967        rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
 968        rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
 969
 970        err = register_pernet_subsys(&fib_rules_net_ops);
 971        if (err < 0)
 972                goto fail;
 973
 974        err = register_netdevice_notifier(&fib_rules_notifier);
 975        if (err < 0)
 976                goto fail_unregister;
 977
 978        return 0;
 979
 980fail_unregister:
 981        unregister_pernet_subsys(&fib_rules_net_ops);
 982fail:
 983        rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
 984        rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
 985        rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
 986        return err;
 987}
 988
 989subsys_initcall(fib_rules_init);
 990