net/ipv6/fib6_rules.c

   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
  25 struct fib6_rule {
  26         struct fib_rule         common;
  27         struct rt6key           src;
  28         struct rt6key           dst;
  29         u8                      tclass;
  30 };
  31
  32 struct 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
  50 static 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         }
 102 again:
 103         dst_release(&rt->dst);
 104         rt = NULL;
 105         goto out;
 106
 107 discard_pkt:
 108         dst_hold(&rt->dst);
 109 out:
 110         arg->result = rt;
 111         return rt == NULL ? -EAGAIN : 0;
 112 }
 113
 114
 115 static 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
 144 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 145         FRA_GENERIC_POLICY,
 146 };
 147
 148 static 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;
 179 errout:
 180         return err;
 181 }
 182
 183 static 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
 208 static 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
 226 nla_put_failure:
 227         return -ENOBUFS;
 228 }
 229
 230 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 231 {
 232         return 0x3FFF;
 233 }
 234
 235 static 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
 241 static const struct fib_rules_ops __net_initdata 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
 258 static 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
 279 out:
 280         return err;
 281
 282 out_fib6_rules_ops:
 283         fib_rules_unregister(ops);
 284         goto out;
 285 }
 286
 287 static void __net_exit fib6_rules_net_exit(struct net *net)
 288 {
 289         fib_rules_unregister(net->ipv6.fib6_rules_ops);
 290 }
 291
 292 static struct pernet_operations fib6_rules_net_ops = {
 293         .init = fib6_rules_net_init,
 294         .exit = fib6_rules_net_exit,
 295 };
 296
 297 int __init fib6_rules_init(void)
 298 {
 299         return register_pernet_subsys(&fib6_rules_net_ops);
 300 }
 301
 302
 303 void fib6_rules_cleanup(void)
 304 {
 305         unregister_pernet_subsys(&fib6_rules_net_ops);
 306 }