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
  18 #include <net/fib_rules.h>
  19 #include <net/ipv6.h>
  20 #include <net/addrconf.h>
  21 #include <net/ip6_route.h>
  22 #include <net/netlink.h>
  23
  24 struct fib6_rule
  25 {
  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 flowi *fl,
  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, fl, flags, &arg);
  41
  42         if (arg.result)
  43                 return arg.result;
  44
  45         dst_hold(&net->ipv6.ip6_null_entry->dst);
  46         return &net->ipv6.ip6_null_entry->dst;
  47 }
  48
  49 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  50                             int flags, struct fib_lookup_arg *arg)
  51 {
  52         struct rt6_info *rt = NULL;
  53         struct fib6_table *table;
  54         struct net *net = rule->fr_net;
  55         pol_lookup_t lookup = arg->lookup_ptr;
  56
  57         switch (rule->action) {
  58         case FR_ACT_TO_TBL:
  59                 break;
  60         case FR_ACT_UNREACHABLE:
  61                 rt = net->ipv6.ip6_null_entry;
  62                 goto discard_pkt;
  63         default:
  64         case FR_ACT_BLACKHOLE:
  65                 rt = net->ipv6.ip6_blk_hole_entry;
  66                 goto discard_pkt;
  67         case FR_ACT_PROHIBIT:
  68                 rt = net->ipv6.ip6_prohibit_entry;
  69                 goto discard_pkt;
  70         }
  71
  72         table = fib6_get_table(net, rule->table);
  73         if (table)
  74                 rt = lookup(net, table, flp, flags);
  75
  76         if (rt != net->ipv6.ip6_null_entry) {
  77                 struct fib6_rule *r = (struct fib6_rule *)rule;
  78
  79                 /*
  80                  * If we need to find a source address for this traffic,
  81                  * we check the result if it meets requirement of the rule.
  82                  */
  83                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  84                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  85                         struct in6_addr saddr;
  86
  87                         if (ipv6_dev_get_saddr(net,
  88                                                ip6_dst_idev(&rt->dst)->dev,
  89                                                &flp->fl6_dst,
  90                                                rt6_flags2srcprefs(flags),
  91                                                &saddr))
  92                                 goto again;
  93                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
  94                                                r->src.plen))
  95                                 goto again;
  96                         ipv6_addr_copy(&flp->fl6_src, &saddr);
  97                 }
  98                 goto out;
  99         }
 100 again:
 101         dst_release(&rt->dst);
 102         rt = NULL;
 103         goto out;
 104
 105 discard_pkt:
 106         dst_hold(&rt->dst);
 107 out:
 108         arg->result = rt;
 109         return rt == NULL ? -EAGAIN : 0;
 110 }
 111
 112
 113 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 114 {
 115         struct fib6_rule *r = (struct fib6_rule *) rule;
 116
 117         if (r->dst.plen &&
 118             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 119                 return 0;
 120
 121         /*
 122          * If FIB_RULE_FIND_SADDR is set and we do not have a
 123          * source address for the traffic, we defer check for
 124          * source address.
 125          */
 126         if (r->src.plen) {
 127                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 128                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 129                                                r->src.plen))
 130                                 return 0;
 131                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 132                         return 0;
 133         }
 134
 135         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 136                 return 0;
 137
 138         return 1;
 139 }
 140
 141 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 142         FRA_GENERIC_POLICY,
 143 };
 144
 145 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 146                                struct fib_rule_hdr *frh,
 147                                struct nlattr **tb)
 148 {
 149         int err = -EINVAL;
 150         struct net *net = sock_net(skb->sk);
 151         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 152
 153         if (rule->action == FR_ACT_TO_TBL) {
 154                 if (rule->table == RT6_TABLE_UNSPEC)
 155                         goto errout;
 156
 157                 if (fib6_new_table(net, rule->table) == NULL) {
 158                         err = -ENOBUFS;
 159                         goto errout;
 160                 }
 161         }
 162
 163         if (frh->src_len)
 164                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 165                            sizeof(struct in6_addr));
 166
 167         if (frh->dst_len)
 168                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 169                            sizeof(struct in6_addr));
 170
 171         rule6->src.plen = frh->src_len;
 172         rule6->dst.plen = frh->dst_len;
 173         rule6->tclass = frh->tos;
 174
 175         err = 0;
 176 errout:
 177         return err;
 178 }
 179
 180 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 181                              struct nlattr **tb)
 182 {
 183         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 184
 185         if (frh->src_len && (rule6->src.plen != frh->src_len))
 186                 return 0;
 187
 188         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 189                 return 0;
 190
 191         if (frh->tos && (rule6->tclass != frh->tos))
 192                 return 0;
 193
 194         if (frh->src_len &&
 195             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 196                 return 0;
 197
 198         if (frh->dst_len &&
 199             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 200                 return 0;
 201
 202         return 1;
 203 }
 204
 205 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 206                           struct fib_rule_hdr *frh)
 207 {
 208         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 209
 210         frh->dst_len = rule6->dst.plen;
 211         frh->src_len = rule6->src.plen;
 212         frh->tos = rule6->tclass;
 213
 214         if (rule6->dst.plen)
 215                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 216                         &rule6->dst.addr);
 217
 218         if (rule6->src.plen)
 219                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 220                         &rule6->src.addr);
 221
 222         return 0;
 223
 224 nla_put_failure:
 225         return -ENOBUFS;
 226 }
 227
 228 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 229 {
 230         return 0x3FFF;
 231 }
 232
 233 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 234 {
 235         return nla_total_size(16) /* dst */
 236                + nla_total_size(16); /* src */
 237 }
 238
 239 static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = {
 240         .family                 = AF_INET6,
 241         .rule_size              = sizeof(struct fib6_rule),
 242         .addr_size              = sizeof(struct in6_addr),
 243         .action                 = fib6_rule_action,
 244         .match                  = fib6_rule_match,
 245         .configure              = fib6_rule_configure,
 246         .compare                = fib6_rule_compare,
 247         .fill                   = fib6_rule_fill,
 248         .default_pref           = fib6_rule_default_pref,
 249         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 250         .nlgroup                = RTNLGRP_IPV6_RULE,
 251         .policy                 = fib6_rule_policy,
 252         .owner                  = THIS_MODULE,
 253         .fro_net                = &init_net,
 254 };
 255
 256 static int __net_init fib6_rules_net_init(struct net *net)
 257 {
 258         struct fib_rules_ops *ops;
 259         int err = -ENOMEM;
 260
 261         ops = fib_rules_register(&fib6_rules_ops_template, net);
 262         if (IS_ERR(ops))
 263                 return PTR_ERR(ops);
 264         net->ipv6.fib6_rules_ops = ops;
 265
 266
 267         err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 268                                    RT6_TABLE_LOCAL, 0);
 269         if (err)
 270                 goto out_fib6_rules_ops;
 271
 272         err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
 273                                    0x7FFE, RT6_TABLE_MAIN, 0);
 274         if (err)
 275                 goto out_fib6_rules_ops;
 276
 277 out:
 278         return err;
 279
 280 out_fib6_rules_ops:
 281         fib_rules_unregister(ops);
 282         goto out;
 283 }
 284
 285 static void __net_exit fib6_rules_net_exit(struct net *net)
 286 {
 287         fib_rules_unregister(net->ipv6.fib6_rules_ops);
 288 }
 289
 290 static struct pernet_operations fib6_rules_net_ops = {
 291         .init = fib6_rules_net_init,
 292         .exit = fib6_rules_net_exit,
 293 };
 294
 295 int __init fib6_rules_init(void)
 296 {
 297         return register_pernet_subsys(&fib6_rules_net_ops);
 298 }
 299
 300
 301 void fib6_rules_cleanup(void)
 302 {
 303         unregister_pernet_subsys(&fib6_rules_net_ops);
 304 }