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
  88                         if (ipv6_dev_get_saddr(net,
  89                                                ip6_dst_idev(&rt->u.dst)->dev,
  90                                                &flp->fl6_dst,
  91                                                rt6_flags2srcprefs(flags),
  92                                                &saddr))
  93                                 goto again;
  94                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
  95                                                r->src.plen))
  96                                 goto again;
  97                         ipv6_addr_copy(&flp->fl6_src, &saddr);
  98                 }
  99                 goto out;
 100         }
 101 again:
 102         dst_release(&rt->u.dst);
 103         rt = NULL;
 104         goto out;
 105
 106 discard_pkt:
 107         dst_hold(&rt->u.dst);
 108 out:
 109         arg->result = rt;
 110         return rt == NULL ? -EAGAIN : 0;
 111 }
 112
 113
 114 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 115 {
 116         struct fib6_rule *r = (struct fib6_rule *) rule;
 117
 118         if (r->dst.plen &&
 119             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 120                 return 0;
 121
 122         /*
 123          * If FIB_RULE_FIND_SADDR is set and we do not have a
 124          * source address for the traffic, we defer check for
 125          * source address.
 126          */
 127         if (r->src.plen) {
 128                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 129                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 130                                                r->src.plen))
 131                                 return 0;
 132                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 133                         return 0;
 134         }
 135
 136         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 137                 return 0;
 138
 139         return 1;
 140 }
 141
 142 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 143         FRA_GENERIC_POLICY,
 144 };
 145
 146 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 147                                struct fib_rule_hdr *frh,
 148                                struct nlattr **tb)
 149 {
 150         int err = -EINVAL;
 151         struct net *net = sock_net(skb->sk);
 152         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 153
 154         if (rule->action == FR_ACT_TO_TBL) {
 155                 if (rule->table == RT6_TABLE_UNSPEC)
 156                         goto errout;
 157
 158                 if (fib6_new_table(net, rule->table) == NULL) {
 159                         err = -ENOBUFS;
 160                         goto errout;
 161                 }
 162         }
 163
 164         if (frh->src_len)
 165                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 166                            sizeof(struct in6_addr));
 167
 168         if (frh->dst_len)
 169                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 170                            sizeof(struct in6_addr));
 171
 172         rule6->src.plen = frh->src_len;
 173         rule6->dst.plen = frh->dst_len;
 174         rule6->tclass = frh->tos;
 175
 176         err = 0;
 177 errout:
 178         return err;
 179 }
 180
 181 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 182                              struct nlattr **tb)
 183 {
 184         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 185
 186         if (frh->src_len && (rule6->src.plen != frh->src_len))
 187                 return 0;
 188
 189         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 190                 return 0;
 191
 192         if (frh->tos && (rule6->tclass != frh->tos))
 193                 return 0;
 194
 195         if (frh->src_len &&
 196             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 197                 return 0;
 198
 199         if (frh->dst_len &&
 200             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 201                 return 0;
 202
 203         return 1;
 204 }
 205
 206 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 207                           struct fib_rule_hdr *frh)
 208 {
 209         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 210
 211         frh->dst_len = rule6->dst.plen;
 212         frh->src_len = rule6->src.plen;
 213         frh->tos = rule6->tclass;
 214
 215         if (rule6->dst.plen)
 216                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 217                         &rule6->dst.addr);
 218
 219         if (rule6->src.plen)
 220                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 221                         &rule6->src.addr);
 222
 223         return 0;
 224
 225 nla_put_failure:
 226         return -ENOBUFS;
 227 }
 228
 229 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 230 {
 231         return 0x3FFF;
 232 }
 233
 234 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 235 {
 236         return nla_total_size(16) /* dst */
 237                + nla_total_size(16); /* src */
 238 }
 239
 240 static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = {
 241         .family                 = AF_INET6,
 242         .rule_size              = sizeof(struct fib6_rule),
 243         .addr_size              = sizeof(struct in6_addr),
 244         .action                 = fib6_rule_action,
 245         .match                  = fib6_rule_match,
 246         .configure              = fib6_rule_configure,
 247         .compare                = fib6_rule_compare,
 248         .fill                   = fib6_rule_fill,
 249         .default_pref           = fib6_rule_default_pref,
 250         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 251         .nlgroup                = RTNLGRP_IPV6_RULE,
 252         .policy                 = fib6_rule_policy,
 253         .owner                  = THIS_MODULE,
 254         .fro_net                = &init_net,
 255 };
 256
 257 static int __net_init fib6_rules_net_init(struct net *net)
 258 {
 259         struct fib_rules_ops *ops;
 260         int err = -ENOMEM;
 261
 262         ops = fib_rules_register(&fib6_rules_ops_template, net);
 263         if (IS_ERR(ops))
 264                 return PTR_ERR(ops);
 265         net->ipv6.fib6_rules_ops = ops;
 266
 267
 268         err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 269                                    RT6_TABLE_LOCAL, 0);
 270         if (err)
 271                 goto out_fib6_rules_ops;
 272
 273         err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
 274                                    0x7FFE, RT6_TABLE_MAIN, 0);
 275         if (err)
 276                 goto out_fib6_rules_ops;
 277
 278 out:
 279         return err;
 280
 281 out_fib6_rules_ops:
 282         fib_rules_unregister(ops);
 283         goto out;
 284 }
 285
 286 static void __net_exit fib6_rules_net_exit(struct net *net)
 287 {
 288         fib_rules_unregister(net->ipv6.fib6_rules_ops);
 289 }
 290
 291 static struct pernet_operations fib6_rules_net_ops = {
 292         .init = fib6_rules_net_init,
 293         .exit = fib6_rules_net_exit,
 294 };
 295
 296 int __init fib6_rules_init(void)
 297 {
 298         return register_pernet_subsys(&fib6_rules_net_ops);
 299 }
 300
 301
 302 void fib6_rules_cleanup(void)
 303 {
 304         unregister_pernet_subsys(&fib6_rules_net_ops);
 305 }