linux/net/ipv6/fib6_rules.c
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   1/*
   2 * net/ipv6/fib6_rules.c        IPv6 Routing Policy Rules
   3 *
   4 * Copyright (C)2003-2006 Helsinki University of Technology
   5 * Copyright (C)2003-2006 USAGI/WIDE Project
   6 *
   7 *      This program is free software; you can redistribute it and/or
   8 *      modify it under the terms of the GNU General Public License as
   9 *      published by the Free Software Foundation, version 2.
  10 *
  11 * Authors
  12 *      Thomas Graf             <tgraf@suug.ch>
  13 *      Ville Nuorvala          <vnuorval@tcs.hut.fi>
  14 */
  15
  16#include <linux/netdevice.h>
  17#include <linux/export.h>
  18
  19#include <net/fib_rules.h>
  20#include <net/ipv6.h>
  21#include <net/addrconf.h>
  22#include <net/ip6_route.h>
  23#include <net/netlink.h>
  24
  25struct fib6_rule {
  26        struct fib_rule         common;
  27        struct rt6key           src;
  28        struct rt6key           dst;
  29        u8                      tclass;
  30};
  31
  32struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
  33                                   int flags, pol_lookup_t lookup)
  34{
  35        struct fib_lookup_arg arg = {
  36                .lookup_ptr = lookup,
  37                .flags = FIB_LOOKUP_NOREF,
  38        };
  39
  40        fib_rules_lookup(net->ipv6.fib6_rules_ops,
  41                         flowi6_to_flowi(fl6), flags, &arg);
  42
  43        if (arg.result)
  44                return arg.result;
  45
  46        dst_hold(&net->ipv6.ip6_null_entry->dst);
  47        return &net->ipv6.ip6_null_entry->dst;
  48}
  49
  50static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  51                            int flags, struct fib_lookup_arg *arg)
  52{
  53        struct flowi6 *flp6 = &flp->u.ip6;
  54        struct rt6_info *rt = NULL;
  55        struct fib6_table *table;
  56        struct net *net = rule->fr_net;
  57        pol_lookup_t lookup = arg->lookup_ptr;
  58
  59        switch (rule->action) {
  60        case FR_ACT_TO_TBL:
  61                break;
  62        case FR_ACT_UNREACHABLE:
  63                rt = net->ipv6.ip6_null_entry;
  64                goto discard_pkt;
  65        default:
  66        case FR_ACT_BLACKHOLE:
  67                rt = net->ipv6.ip6_blk_hole_entry;
  68                goto discard_pkt;
  69        case FR_ACT_PROHIBIT:
  70                rt = net->ipv6.ip6_prohibit_entry;
  71                goto discard_pkt;
  72        }
  73
  74        table = fib6_get_table(net, rule->table);
  75        if (table)
  76                rt = lookup(net, table, flp6, flags);
  77
  78        if (rt != net->ipv6.ip6_null_entry) {
  79                struct fib6_rule *r = (struct fib6_rule *)rule;
  80
  81                /*
  82                 * If we need to find a source address for this traffic,
  83                 * we check the result if it meets requirement of the rule.
  84                 */
  85                if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  86                    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  87                        struct in6_addr saddr;
  88
  89                        if (ipv6_dev_get_saddr(net,
  90                                               ip6_dst_idev(&rt->dst)->dev,
  91                                               &flp6->daddr,
  92                                               rt6_flags2srcprefs(flags),
  93                                               &saddr))
  94                                goto again;
  95                        if (!ipv6_prefix_equal(&saddr, &r->src.addr,
  96                                               r->src.plen))
  97                                goto again;
  98                        flp6->saddr = saddr;
  99                }
 100                goto out;
 101        }
 102again:
 103        dst_release(&rt->dst);
 104        rt = NULL;
 105        goto out;
 106
 107discard_pkt:
 108        dst_hold(&rt->dst);
 109out:
 110        arg->result = rt;
 111        return rt == NULL ? -EAGAIN : 0;
 112}
 113
 114
 115static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 116{
 117        struct fib6_rule *r = (struct fib6_rule *) rule;
 118        struct flowi6 *fl6 = &fl->u.ip6;
 119
 120        if (r->dst.plen &&
 121            !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
 122                return 0;
 123
 124        /*
 125         * If FIB_RULE_FIND_SADDR is set and we do not have a
 126         * source address for the traffic, we defer check for
 127         * source address.
 128         */
 129        if (r->src.plen) {
 130                if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 131                        if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
 132                                               r->src.plen))
 133                                return 0;
 134                } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 135                        return 0;
 136        }
 137
 138        if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff))
 139                return 0;
 140
 141        return 1;
 142}
 143
 144static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 145        FRA_GENERIC_POLICY,
 146};
 147
 148static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 149                               struct fib_rule_hdr *frh,
 150                               struct nlattr **tb)
 151{
 152        int err = -EINVAL;
 153        struct net *net = sock_net(skb->sk);
 154        struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 155
 156        if (rule->action == FR_ACT_TO_TBL) {
 157                if (rule->table == RT6_TABLE_UNSPEC)
 158                        goto errout;
 159
 160                if (fib6_new_table(net, rule->table) == NULL) {
 161                        err = -ENOBUFS;
 162                        goto errout;
 163                }
 164        }
 165
 166        if (frh->src_len)
 167                nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 168                           sizeof(struct in6_addr));
 169
 170        if (frh->dst_len)
 171                nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 172                           sizeof(struct in6_addr));
 173
 174        rule6->src.plen = frh->src_len;
 175        rule6->dst.plen = frh->dst_len;
 176        rule6->tclass = frh->tos;
 177
 178        err = 0;
 179errout:
 180        return err;
 181}
 182
 183static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 184                             struct nlattr **tb)
 185{
 186        struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 187
 188        if (frh->src_len && (rule6->src.plen != frh->src_len))
 189                return 0;
 190
 191        if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 192                return 0;
 193
 194        if (frh->tos && (rule6->tclass != frh->tos))
 195                return 0;
 196
 197        if (frh->src_len &&
 198            nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 199                return 0;
 200
 201        if (frh->dst_len &&
 202            nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 203                return 0;
 204
 205        return 1;
 206}
 207
 208static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 209                          struct fib_rule_hdr *frh)
 210{
 211        struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 212
 213        frh->dst_len = rule6->dst.plen;
 214        frh->src_len = rule6->src.plen;
 215        frh->tos = rule6->tclass;
 216
 217        if ((rule6->dst.plen &&
 218             nla_put(skb, FRA_DST, sizeof(struct in6_addr),
 219                     &rule6->dst.addr)) ||
 220            (rule6->src.plen &&
 221             nla_put(skb, FRA_SRC, sizeof(struct in6_addr),
 222                     &rule6->src.addr)))
 223                goto nla_put_failure;
 224        return 0;
 225
 226nla_put_failure:
 227        return -ENOBUFS;
 228}
 229
 230static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 231{
 232        return 0x3FFF;
 233}
 234
 235static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 236{
 237        return nla_total_size(16) /* dst */
 238               + nla_total_size(16); /* src */
 239}
 240
 241static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
 242        .family                 = AF_INET6,
 243        .rule_size              = sizeof(struct fib6_rule),
 244        .addr_size              = sizeof(struct in6_addr),
 245        .action                 = fib6_rule_action,
 246        .match                  = fib6_rule_match,
 247        .configure              = fib6_rule_configure,
 248        .compare                = fib6_rule_compare,
 249        .fill                   = fib6_rule_fill,
 250        .default_pref           = fib6_rule_default_pref,
 251        .nlmsg_payload          = fib6_rule_nlmsg_payload,
 252        .nlgroup                = RTNLGRP_IPV6_RULE,
 253        .policy                 = fib6_rule_policy,
 254        .owner                  = THIS_MODULE,
 255        .fro_net                = &init_net,
 256};
 257
 258static int __net_init fib6_rules_net_init(struct net *net)
 259{
 260        struct fib_rules_ops *ops;
 261        int err = -ENOMEM;
 262
 263        ops = fib_rules_register(&fib6_rules_ops_template, net);
 264        if (IS_ERR(ops))
 265                return PTR_ERR(ops);
 266        net->ipv6.fib6_rules_ops = ops;
 267
 268
 269        err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 270                                   RT6_TABLE_LOCAL, 0);
 271        if (err)
 272                goto out_fib6_rules_ops;
 273
 274        err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
 275                                   0x7FFE, RT6_TABLE_MAIN, 0);
 276        if (err)
 277                goto out_fib6_rules_ops;
 278
 279out:
 280        return err;
 281
 282out_fib6_rules_ops:
 283        fib_rules_unregister(ops);
 284        goto out;
 285}
 286
 287static void __net_exit fib6_rules_net_exit(struct net *net)
 288{
 289        fib_rules_unregister(net->ipv6.fib6_rules_ops);
 290}
 291
 292static struct pernet_operations fib6_rules_net_ops = {
 293        .init = fib6_rules_net_init,
 294        .exit = fib6_rules_net_exit,
 295};
 296
 297int __init fib6_rules_init(void)
 298{
 299        return register_pernet_subsys(&fib6_rules_net_ops);
 300}
 301
 302
 303void fib6_rules_cleanup(void)
 304{
 305        unregister_pernet_subsys(&fib6_rules_net_ops);
 306}
 307
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