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         };
  38
  39         fib_rules_lookup(net->ipv6.fib6_rules_ops, fl, flags, &arg);
  40         if (arg.rule)
  41                 fib_rule_put(arg.rule);
  42
  43         if (arg.result)
  44                 return arg.result;
  45
  46         dst_hold(&net->ipv6.ip6_null_entry->u.dst);
  47         return &net->ipv6.ip6_null_entry->u.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 rt6_info *rt = NULL;
  54         struct fib6_table *table;
  55         struct net *net = rule->fr_net;
  56         pol_lookup_t lookup = arg->lookup_ptr;
  57
  58         switch (rule->action) {
  59         case FR_ACT_TO_TBL:
  60                 break;
  61         case FR_ACT_UNREACHABLE:
  62                 rt = net->ipv6.ip6_null_entry;
  63                 goto discard_pkt;
  64         default:
  65         case FR_ACT_BLACKHOLE:
  66                 rt = net->ipv6.ip6_blk_hole_entry;
  67                 goto discard_pkt;
  68         case FR_ACT_PROHIBIT:
  69                 rt = net->ipv6.ip6_prohibit_entry;
  70                 goto discard_pkt;
  71         }
  72
  73         table = fib6_get_table(net, rule->table);
  74         if (table)
  75                 rt = lookup(net, table, flp, flags);
  76
  77         if (rt != net->ipv6.ip6_null_entry) {
  78                 struct fib6_rule *r = (struct fib6_rule *)rule;
  79
  80                 /*
  81                  * If we need to find a source address for this traffic,
  82                  * we check the result if it meets requirement of the rule.
  83                  */
  84                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  85                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  86                         struct in6_addr saddr;
  87                         unsigned int srcprefs = 0;
  88
  89                         if (flags & RT6_LOOKUP_F_SRCPREF_TMP)
  90                                 srcprefs |= IPV6_PREFER_SRC_TMP;
  91                         if (flags & RT6_LOOKUP_F_SRCPREF_PUBLIC)
  92                                 srcprefs |= IPV6_PREFER_SRC_PUBLIC;
  93                         if (flags & RT6_LOOKUP_F_SRCPREF_COA)
  94                                 srcprefs |= IPV6_PREFER_SRC_COA;
  95
  96                         if (ipv6_dev_get_saddr(net,
  97                                                ip6_dst_idev(&rt->u.dst)->dev,
  98                                                &flp->fl6_dst, srcprefs,
  99                                                &saddr))
 100                                 goto again;
 101                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
 102                                                r->src.plen))
 103                                 goto again;
 104                         ipv6_addr_copy(&flp->fl6_src, &saddr);
 105                 }
 106                 goto out;
 107         }
 108 again:
 109         dst_release(&rt->u.dst);
 110         rt = NULL;
 111         goto out;
 112
 113 discard_pkt:
 114         dst_hold(&rt->u.dst);
 115 out:
 116         arg->result = rt;
 117         return rt == NULL ? -EAGAIN : 0;
 118 }
 119
 120
 121 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 122 {
 123         struct fib6_rule *r = (struct fib6_rule *) rule;
 124
 125         if (r->dst.plen &&
 126             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 127                 return 0;
 128
 129         /*
 130          * If FIB_RULE_FIND_SADDR is set and we do not have a
 131          * source address for the traffic, we defer check for
 132          * source address.
 133          */
 134         if (r->src.plen) {
 135                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 136                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 137                                                r->src.plen))
 138                                 return 0;
 139                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 140                         return 0;
 141         }
 142
 143         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 144                 return 0;
 145
 146         return 1;
 147 }
 148
 149 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 150         FRA_GENERIC_POLICY,
 151 };
 152
 153 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 154                                struct fib_rule_hdr *frh,
 155                                struct nlattr **tb)
 156 {
 157         int err = -EINVAL;
 158         struct net *net = sock_net(skb->sk);
 159         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 160
 161         if (rule->action == FR_ACT_TO_TBL) {
 162                 if (rule->table == RT6_TABLE_UNSPEC)
 163                         goto errout;
 164
 165                 if (fib6_new_table(net, rule->table) == NULL) {
 166                         err = -ENOBUFS;
 167                         goto errout;
 168                 }
 169         }
 170
 171         if (frh->src_len)
 172                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 173                            sizeof(struct in6_addr));
 174
 175         if (frh->dst_len)
 176                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 177                            sizeof(struct in6_addr));
 178
 179         rule6->src.plen = frh->src_len;
 180         rule6->dst.plen = frh->dst_len;
 181         rule6->tclass = frh->tos;
 182
 183         err = 0;
 184 errout:
 185         return err;
 186 }
 187
 188 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 189                              struct nlattr **tb)
 190 {
 191         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 192
 193         if (frh->src_len && (rule6->src.plen != frh->src_len))
 194                 return 0;
 195
 196         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 197                 return 0;
 198
 199         if (frh->tos && (rule6->tclass != frh->tos))
 200                 return 0;
 201
 202         if (frh->src_len &&
 203             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 204                 return 0;
 205
 206         if (frh->dst_len &&
 207             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 208                 return 0;
 209
 210         return 1;
 211 }
 212
 213 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 214                           struct fib_rule_hdr *frh)
 215 {
 216         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 217
 218         frh->family = AF_INET6;
 219         frh->dst_len = rule6->dst.plen;
 220         frh->src_len = rule6->src.plen;
 221         frh->tos = rule6->tclass;
 222
 223         if (rule6->dst.plen)
 224                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 225                         &rule6->dst.addr);
 226
 227         if (rule6->src.plen)
 228                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 229                         &rule6->src.addr);
 230
 231         return 0;
 232
 233 nla_put_failure:
 234         return -ENOBUFS;
 235 }
 236
 237 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 238 {
 239         return 0x3FFF;
 240 }
 241
 242 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 243 {
 244         return nla_total_size(16) /* dst */
 245                + nla_total_size(16); /* src */
 246 }
 247
 248 static struct fib_rules_ops fib6_rules_ops_template = {
 249         .family                 = AF_INET6,
 250         .rule_size              = sizeof(struct fib6_rule),
 251         .addr_size              = sizeof(struct in6_addr),
 252         .action                 = fib6_rule_action,
 253         .match                  = fib6_rule_match,
 254         .configure              = fib6_rule_configure,
 255         .compare                = fib6_rule_compare,
 256         .fill                   = fib6_rule_fill,
 257         .default_pref           = fib6_rule_default_pref,
 258         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 259         .nlgroup                = RTNLGRP_IPV6_RULE,
 260         .policy                 = fib6_rule_policy,
 261         .owner                  = THIS_MODULE,
 262         .fro_net                = &init_net,
 263 };
 264
 265 static int __net_init fib6_rules_net_init(struct net *net)
 266 {
 267         struct fib_rules_ops *ops;
 268         int err = -ENOMEM;
 269
 270         ops = fib_rules_register(&fib6_rules_ops_template, net);
 271         if (IS_ERR(ops))
 272                 return PTR_ERR(ops);
 273         net->ipv6.fib6_rules_ops = ops;
 274
 275
 276         err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 277                                    RT6_TABLE_LOCAL, 0);
 278         if (err)
 279                 goto out_fib6_rules_ops;
 280
 281         err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
 282                                    0x7FFE, RT6_TABLE_MAIN, 0);
 283         if (err)
 284                 goto out_fib6_rules_ops;
 285
 286 out:
 287         return err;
 288
 289 out_fib6_rules_ops:
 290         fib_rules_unregister(ops);
 291         goto out;
 292 }
 293
 294 static void __net_exit fib6_rules_net_exit(struct net *net)
 295 {
 296         fib_rules_unregister(net->ipv6.fib6_rules_ops);
 297 }
 298
 299 static struct pernet_operations fib6_rules_net_ops = {
 300         .init = fib6_rules_net_init,
 301         .exit = fib6_rules_net_exit,
 302 };
 303
 304 int __init fib6_rules_init(void)
 305 {
 306         return register_pernet_subsys(&fib6_rules_net_ops);
 307 }
 308
 309
 310 void fib6_rules_cleanup(void)
 311 {
 312         unregister_pernet_subsys(&fib6_rules_net_ops);
 313 }