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 {
  27         struct fib_rule         common;
  28         struct rt6key           src;
  29         struct rt6key           dst;
  30         u8                      tclass;
  31 };
  32
  33 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
  34                                    int flags, pol_lookup_t lookup)
  35 {
  36         struct fib_lookup_arg arg = {
  37                 .lookup_ptr = lookup,
  38                 .flags = FIB_LOOKUP_NOREF,
  39         };
  40
  41         fib_rules_lookup(net->ipv6.fib6_rules_ops,
  42                          flowi6_to_flowi(fl6), flags, &arg);
  43
  44         if (arg.result)
  45                 return arg.result;
  46
  47         dst_hold(&net->ipv6.ip6_null_entry->dst);
  48         return &net->ipv6.ip6_null_entry->dst;
  49 }
  50
  51 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  52                             int flags, struct fib_lookup_arg *arg)
  53 {
  54         struct flowi6 *flp6 = &flp->u.ip6;
  55         struct rt6_info *rt = NULL;
  56         struct fib6_table *table;
  57         struct net *net = rule->fr_net;
  58         pol_lookup_t lookup = arg->lookup_ptr;
  59
  60         switch (rule->action) {
  61         case FR_ACT_TO_TBL:
  62                 break;
  63         case FR_ACT_UNREACHABLE:
  64                 rt = net->ipv6.ip6_null_entry;
  65                 goto discard_pkt;
  66         default:
  67         case FR_ACT_BLACKHOLE:
  68                 rt = net->ipv6.ip6_blk_hole_entry;
  69                 goto discard_pkt;
  70         case FR_ACT_PROHIBIT:
  71                 rt = net->ipv6.ip6_prohibit_entry;
  72                 goto discard_pkt;
  73         }
  74
  75         table = fib6_get_table(net, rule->table);
  76         if (table)
  77                 rt = lookup(net, table, flp6, flags);
  78
  79         if (rt != net->ipv6.ip6_null_entry) {
  80                 struct fib6_rule *r = (struct fib6_rule *)rule;
  81
  82                 /*
  83                  * If we need to find a source address for this traffic,
  84                  * we check the result if it meets requirement of the rule.
  85                  */
  86                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  87                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  88                         struct in6_addr saddr;
  89
  90                         if (ipv6_dev_get_saddr(net,
  91                                                ip6_dst_idev(&rt->dst)->dev,
  92                                                &flp6->daddr,
  93                                                rt6_flags2srcprefs(flags),
  94                                                &saddr))
  95                                 goto again;
  96                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
  97                                                r->src.plen))
  98                                 goto again;
  99                         ipv6_addr_copy(&flp6->saddr, &saddr);
 100                 }
 101                 goto out;
 102         }
 103 again:
 104         dst_release(&rt->dst);
 105         rt = NULL;
 106         goto out;
 107
 108 discard_pkt:
 109         dst_hold(&rt->dst);
 110 out:
 111         arg->result = rt;
 112         return rt == NULL ? -EAGAIN : 0;
 113 }
 114
 115
 116 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 117 {
 118         struct fib6_rule *r = (struct fib6_rule *) rule;
 119         struct flowi6 *fl6 = &fl->u.ip6;
 120
 121         if (r->dst.plen &&
 122             !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
 123                 return 0;
 124
 125         /*
 126          * If FIB_RULE_FIND_SADDR is set and we do not have a
 127          * source address for the traffic, we defer check for
 128          * source address.
 129          */
 130         if (r->src.plen) {
 131                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 132                         if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
 133                                                r->src.plen))
 134                                 return 0;
 135                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 136                         return 0;
 137         }
 138
 139         if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff))
 140                 return 0;
 141
 142         return 1;
 143 }
 144
 145 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 146         FRA_GENERIC_POLICY,
 147 };
 148
 149 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 150                                struct fib_rule_hdr *frh,
 151                                struct nlattr **tb)
 152 {
 153         int err = -EINVAL;
 154         struct net *net = sock_net(skb->sk);
 155         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 156
 157         if (rule->action == FR_ACT_TO_TBL) {
 158                 if (rule->table == RT6_TABLE_UNSPEC)
 159                         goto errout;
 160
 161                 if (fib6_new_table(net, rule->table) == NULL) {
 162                         err = -ENOBUFS;
 163                         goto errout;
 164                 }
 165         }
 166
 167         if (frh->src_len)
 168                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 169                            sizeof(struct in6_addr));
 170
 171         if (frh->dst_len)
 172                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 173                            sizeof(struct in6_addr));
 174
 175         rule6->src.plen = frh->src_len;
 176         rule6->dst.plen = frh->dst_len;
 177         rule6->tclass = frh->tos;
 178
 179         err = 0;
 180 errout:
 181         return err;
 182 }
 183
 184 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 185                              struct nlattr **tb)
 186 {
 187         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 188
 189         if (frh->src_len && (rule6->src.plen != frh->src_len))
 190                 return 0;
 191
 192         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 193                 return 0;
 194
 195         if (frh->tos && (rule6->tclass != frh->tos))
 196                 return 0;
 197
 198         if (frh->src_len &&
 199             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 200                 return 0;
 201
 202         if (frh->dst_len &&
 203             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 204                 return 0;
 205
 206         return 1;
 207 }
 208
 209 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 210                           struct fib_rule_hdr *frh)
 211 {
 212         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 213
 214         frh->dst_len = rule6->dst.plen;
 215         frh->src_len = rule6->src.plen;
 216         frh->tos = rule6->tclass;
 217
 218         if (rule6->dst.plen)
 219                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 220                         &rule6->dst.addr);
 221
 222         if (rule6->src.plen)
 223                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 224                         &rule6->src.addr);
 225
 226         return 0;
 227
 228 nla_put_failure:
 229         return -ENOBUFS;
 230 }
 231
 232 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 233 {
 234         return 0x3FFF;
 235 }
 236
 237 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 238 {
 239         return nla_total_size(16) /* dst */
 240                + nla_total_size(16); /* src */
 241 }
 242
 243 static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = {
 244         .family                 = AF_INET6,
 245         .rule_size              = sizeof(struct fib6_rule),
 246         .addr_size              = sizeof(struct in6_addr),
 247         .action                 = fib6_rule_action,
 248         .match                  = fib6_rule_match,
 249         .configure              = fib6_rule_configure,
 250         .compare                = fib6_rule_compare,
 251         .fill                   = fib6_rule_fill,
 252         .default_pref           = fib6_rule_default_pref,
 253         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 254         .nlgroup                = RTNLGRP_IPV6_RULE,
 255         .policy                 = fib6_rule_policy,
 256         .owner                  = THIS_MODULE,
 257         .fro_net                = &init_net,
 258 };
 259
 260 static int __net_init fib6_rules_net_init(struct net *net)
 261 {
 262         struct fib_rules_ops *ops;
 263         int err = -ENOMEM;
 264
 265         ops = fib_rules_register(&fib6_rules_ops_template, net);
 266         if (IS_ERR(ops))
 267                 return PTR_ERR(ops);
 268         net->ipv6.fib6_rules_ops = ops;
 269
 270
 271         err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 272                                    RT6_TABLE_LOCAL, 0);
 273         if (err)
 274                 goto out_fib6_rules_ops;
 275
 276         err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
 277                                    0x7FFE, RT6_TABLE_MAIN, 0);
 278         if (err)
 279                 goto out_fib6_rules_ops;
 280
 281 out:
 282         return err;
 283
 284 out_fib6_rules_ops:
 285         fib_rules_unregister(ops);
 286         goto out;
 287 }
 288
 289 static void __net_exit fib6_rules_net_exit(struct net *net)
 290 {
 291         fib_rules_unregister(net->ipv6.fib6_rules_ops);
 292 }
 293
 294 static struct pernet_operations fib6_rules_net_ops = {
 295         .init = fib6_rules_net_init,
 296         .exit = fib6_rules_net_exit,
 297 };
 298
 299 int __init fib6_rules_init(void)
 300 {
 301         return register_pernet_subsys(&fib6_rules_net_ops);
 302 }
 303
 304
 305 void fib6_rules_cleanup(void)
 306 {
 307         unregister_pernet_subsys(&fib6_rules_net_ops);
 308 }