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/ip6_route.h>
  21 #include <net/netlink.h>
  22
  23 struct fib6_rule
  24 {
  25         struct fib_rule         common;
  26         struct rt6key           src;
  27         struct rt6key           dst;
  28         u8                      tclass;
  29 };
  30
  31 static struct fib_rules_ops fib6_rules_ops;
  32
  33 static struct fib6_rule main_rule = {
  34         .common = {
  35                 .refcnt =       ATOMIC_INIT(2),
  36                 .pref =         0x7FFE,
  37                 .action =       FR_ACT_TO_TBL,
  38                 .table =        RT6_TABLE_MAIN,
  39         },
  40 };
  41
  42 static struct fib6_rule local_rule = {
  43         .common = {
  44                 .refcnt =       ATOMIC_INIT(2),
  45                 .pref =         0,
  46                 .action =       FR_ACT_TO_TBL,
  47                 .table =        RT6_TABLE_LOCAL,
  48                 .flags =        FIB_RULE_PERMANENT,
  49         },
  50 };
  51
  52 static LIST_HEAD(fib6_rules);
  53
  54 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
  55                                    pol_lookup_t lookup)
  56 {
  57         struct fib_lookup_arg arg = {
  58                 .lookup_ptr = lookup,
  59         };
  60
  61         fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
  62         if (arg.rule)
  63                 fib_rule_put(arg.rule);
  64
  65         if (arg.result)
  66                 return arg.result;
  67
  68         dst_hold(&ip6_null_entry.u.dst);
  69         return &ip6_null_entry.u.dst;
  70 }
  71
  72 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  73                             int flags, struct fib_lookup_arg *arg)
  74 {
  75         struct rt6_info *rt = NULL;
  76         struct fib6_table *table;
  77         pol_lookup_t lookup = arg->lookup_ptr;
  78
  79         switch (rule->action) {
  80         case FR_ACT_TO_TBL:
  81                 break;
  82         case FR_ACT_UNREACHABLE:
  83                 rt = &ip6_null_entry;
  84                 goto discard_pkt;
  85         default:
  86         case FR_ACT_BLACKHOLE:
  87                 rt = &ip6_blk_hole_entry;
  88                 goto discard_pkt;
  89         case FR_ACT_PROHIBIT:
  90                 rt = &ip6_prohibit_entry;
  91                 goto discard_pkt;
  92         }
  93
  94         table = fib6_get_table(rule->table);
  95         if (table)
  96                 rt = lookup(table, flp, flags);
  97
  98         if (rt != &ip6_null_entry)
  99                 goto out;
 100         dst_release(&rt->u.dst);
 101         rt = NULL;
 102         goto out;
 103
 104 discard_pkt:
 105         dst_hold(&rt->u.dst);
 106 out:
 107         arg->result = rt;
 108         return rt == NULL ? -EAGAIN : 0;
 109 }
 110
 111
 112 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 113 {
 114         struct fib6_rule *r = (struct fib6_rule *) rule;
 115
 116         if (r->dst.plen &&
 117             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 118                 return 0;
 119
 120         if (r->src.plen) {
 121                 if (!(flags & RT6_LOOKUP_F_HAS_SADDR) ||
 122                     !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
 123                         return 0;
 124         }
 125
 126         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 127                 return 0;
 128
 129         return 1;
 130 }
 131
 132 static struct nla_policy fib6_rule_policy[FRA_MAX+1] __read_mostly = {
 133         FRA_GENERIC_POLICY,
 134 };
 135
 136 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 137                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 138                                struct nlattr **tb)
 139 {
 140         int err = -EINVAL;
 141         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 142
 143         if (rule->action == FR_ACT_TO_TBL) {
 144                 if (rule->table == RT6_TABLE_UNSPEC)
 145                         goto errout;
 146
 147                 if (fib6_new_table(rule->table) == NULL) {
 148                         err = -ENOBUFS;
 149                         goto errout;
 150                 }
 151         }
 152
 153         if (frh->src_len)
 154                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 155                            sizeof(struct in6_addr));
 156
 157         if (frh->dst_len)
 158                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 159                            sizeof(struct in6_addr));
 160
 161         rule6->src.plen = frh->src_len;
 162         rule6->dst.plen = frh->dst_len;
 163         rule6->tclass = frh->tos;
 164
 165         err = 0;
 166 errout:
 167         return err;
 168 }
 169
 170 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 171                              struct nlattr **tb)
 172 {
 173         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 174
 175         if (frh->src_len && (rule6->src.plen != frh->src_len))
 176                 return 0;
 177
 178         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 179                 return 0;
 180
 181         if (frh->tos && (rule6->tclass != frh->tos))
 182                 return 0;
 183
 184         if (frh->src_len &&
 185             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 186                 return 0;
 187
 188         if (frh->dst_len &&
 189             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 190                 return 0;
 191
 192         return 1;
 193 }
 194
 195 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 196                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 197 {
 198         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 199
 200         frh->family = AF_INET6;
 201         frh->dst_len = rule6->dst.plen;
 202         frh->src_len = rule6->src.plen;
 203         frh->tos = rule6->tclass;
 204
 205         if (rule6->dst.plen)
 206                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 207                         &rule6->dst.addr);
 208
 209         if (rule6->src.plen)
 210                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 211                         &rule6->src.addr);
 212
 213         return 0;
 214
 215 nla_put_failure:
 216         return -ENOBUFS;
 217 }
 218
 219 int fib6_rules_dump(struct sk_buff *skb, struct netlink_callback *cb)
 220 {
 221         return fib_rules_dump(skb, cb, AF_INET6);
 222 }
 223
 224 static u32 fib6_rule_default_pref(void)
 225 {
 226         return 0x3FFF;
 227 }
 228
 229 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 230 {
 231         return nla_total_size(16) /* dst */
 232                + nla_total_size(16); /* src */
 233 }
 234
 235 static struct fib_rules_ops fib6_rules_ops = {
 236         .family                 = AF_INET6,
 237         .rule_size              = sizeof(struct fib6_rule),
 238         .addr_size              = sizeof(struct in6_addr),
 239         .action                 = fib6_rule_action,
 240         .match                  = fib6_rule_match,
 241         .configure              = fib6_rule_configure,
 242         .compare                = fib6_rule_compare,
 243         .fill                   = fib6_rule_fill,
 244         .default_pref           = fib6_rule_default_pref,
 245         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 246         .nlgroup                = RTNLGRP_IPV6_RULE,
 247         .policy                 = fib6_rule_policy,
 248         .rules_list             = &fib6_rules,
 249         .owner                  = THIS_MODULE,
 250 };
 251
 252 void __init fib6_rules_init(void)
 253 {
 254         list_add_tail(&local_rule.common.list, &fib6_rules);
 255         list_add_tail(&main_rule.common.list, &fib6_rules);
 256
 257         fib_rules_register(&fib6_rules_ops);
 258 }
 259
 260 void fib6_rules_cleanup(void)
 261 {
 262         fib_rules_unregister(&fib6_rules_ops);
 263 }