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 static struct fib_rules_ops fib6_rules_ops;
  33
  34 static struct fib6_rule main_rule = {
  35         .common = {
  36                 .refcnt =       ATOMIC_INIT(2),
  37                 .pref =         0x7FFE,
  38                 .action =       FR_ACT_TO_TBL,
  39                 .table =        RT6_TABLE_MAIN,
  40         },
  41 };
  42
  43 static struct fib6_rule local_rule = {
  44         .common = {
  45                 .refcnt =       ATOMIC_INIT(2),
  46                 .pref =         0,
  47                 .action =       FR_ACT_TO_TBL,
  48                 .table =        RT6_TABLE_LOCAL,
  49                 .flags =        FIB_RULE_PERMANENT,
  50         },
  51 };
  52
  53 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
  54                                    pol_lookup_t lookup)
  55 {
  56         struct fib_lookup_arg arg = {
  57                 .lookup_ptr = lookup,
  58         };
  59
  60         fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
  61         if (arg.rule)
  62                 fib_rule_put(arg.rule);
  63
  64         if (arg.result)
  65                 return arg.result;
  66
  67         dst_hold(&ip6_null_entry.u.dst);
  68         return &ip6_null_entry.u.dst;
  69 }
  70
  71 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  72                             int flags, struct fib_lookup_arg *arg)
  73 {
  74         struct rt6_info *rt = NULL;
  75         struct fib6_table *table;
  76         pol_lookup_t lookup = arg->lookup_ptr;
  77
  78         switch (rule->action) {
  79         case FR_ACT_TO_TBL:
  80                 break;
  81         case FR_ACT_UNREACHABLE:
  82                 rt = &ip6_null_entry;
  83                 goto discard_pkt;
  84         default:
  85         case FR_ACT_BLACKHOLE:
  86                 rt = &ip6_blk_hole_entry;
  87                 goto discard_pkt;
  88         case FR_ACT_PROHIBIT:
  89                 rt = &ip6_prohibit_entry;
  90                 goto discard_pkt;
  91         }
  92
  93         table = fib6_get_table(rule->table);
  94         if (table)
  95                 rt = lookup(table, flp, flags);
  96
  97         if (rt != &ip6_null_entry) {
  98                 struct fib6_rule *r = (struct fib6_rule *)rule;
  99
 100                 /*
 101                  * If we need to find a source address for this traffic,
 102                  * we check the result if it meets requirement of the rule.
 103                  */
 104                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
 105                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
 106                         struct in6_addr saddr;
 107                         if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst,
 108                                            &saddr))
 109                                 goto again;
 110                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
 111                                                r->src.plen))
 112                                 goto again;
 113                         ipv6_addr_copy(&flp->fl6_src, &saddr);
 114                 }
 115                 goto out;
 116         }
 117 again:
 118         dst_release(&rt->u.dst);
 119         rt = NULL;
 120         goto out;
 121
 122 discard_pkt:
 123         dst_hold(&rt->u.dst);
 124 out:
 125         arg->result = rt;
 126         return rt == NULL ? -EAGAIN : 0;
 127 }
 128
 129
 130 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 131 {
 132         struct fib6_rule *r = (struct fib6_rule *) rule;
 133
 134         if (r->dst.plen &&
 135             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 136                 return 0;
 137
 138         /*
 139          * If FIB_RULE_FIND_SADDR is set and we do not have a
 140          * source address for the traffic, we defer check for
 141          * source address.
 142          */
 143         if (r->src.plen) {
 144                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 145                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 146                                                r->src.plen))
 147                                 return 0;
 148                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 149                         return 0;
 150         }
 151
 152         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 153                 return 0;
 154
 155         return 1;
 156 }
 157
 158 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 159         FRA_GENERIC_POLICY,
 160 };
 161
 162 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 163                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 164                                struct nlattr **tb)
 165 {
 166         int err = -EINVAL;
 167         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 168
 169         if (rule->action == FR_ACT_TO_TBL) {
 170                 if (rule->table == RT6_TABLE_UNSPEC)
 171                         goto errout;
 172
 173                 if (fib6_new_table(rule->table) == NULL) {
 174                         err = -ENOBUFS;
 175                         goto errout;
 176                 }
 177         }
 178
 179         if (frh->src_len)
 180                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 181                            sizeof(struct in6_addr));
 182
 183         if (frh->dst_len)
 184                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 185                            sizeof(struct in6_addr));
 186
 187         rule6->src.plen = frh->src_len;
 188         rule6->dst.plen = frh->dst_len;
 189         rule6->tclass = frh->tos;
 190
 191         err = 0;
 192 errout:
 193         return err;
 194 }
 195
 196 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 197                              struct nlattr **tb)
 198 {
 199         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 200
 201         if (frh->src_len && (rule6->src.plen != frh->src_len))
 202                 return 0;
 203
 204         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 205                 return 0;
 206
 207         if (frh->tos && (rule6->tclass != frh->tos))
 208                 return 0;
 209
 210         if (frh->src_len &&
 211             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 212                 return 0;
 213
 214         if (frh->dst_len &&
 215             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 216                 return 0;
 217
 218         return 1;
 219 }
 220
 221 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 222                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 223 {
 224         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 225
 226         frh->family = AF_INET6;
 227         frh->dst_len = rule6->dst.plen;
 228         frh->src_len = rule6->src.plen;
 229         frh->tos = rule6->tclass;
 230
 231         if (rule6->dst.plen)
 232                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 233                         &rule6->dst.addr);
 234
 235         if (rule6->src.plen)
 236                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 237                         &rule6->src.addr);
 238
 239         return 0;
 240
 241 nla_put_failure:
 242         return -ENOBUFS;
 243 }
 244
 245 static u32 fib6_rule_default_pref(void)
 246 {
 247         return 0x3FFF;
 248 }
 249
 250 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 251 {
 252         return nla_total_size(16) /* dst */
 253                + nla_total_size(16); /* src */
 254 }
 255
 256 static struct fib_rules_ops fib6_rules_ops = {
 257         .family                 = AF_INET6,
 258         .rule_size              = sizeof(struct fib6_rule),
 259         .addr_size              = sizeof(struct in6_addr),
 260         .action                 = fib6_rule_action,
 261         .match                  = fib6_rule_match,
 262         .configure              = fib6_rule_configure,
 263         .compare                = fib6_rule_compare,
 264         .fill                   = fib6_rule_fill,
 265         .default_pref           = fib6_rule_default_pref,
 266         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 267         .nlgroup                = RTNLGRP_IPV6_RULE,
 268         .policy                 = fib6_rule_policy,
 269         .rules_list             = LIST_HEAD_INIT(fib6_rules_ops.rules_list),
 270         .owner                  = THIS_MODULE,
 271 };
 272
 273 void __init fib6_rules_init(void)
 274 {
 275         list_add_tail(&local_rule.common.list, &fib6_rules_ops.rules_list);
 276         list_add_tail(&main_rule.common.list, &fib6_rules_ops.rules_list);
 277
 278         fib_rules_register(&fib6_rules_ops);
 279 }
 280
 281 void fib6_rules_cleanup(void)
 282 {
 283         fib_rules_unregister(&fib6_rules_ops);
 284 }