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         [FRA_SRC]       = { .len = sizeof(struct in6_addr) },
 135         [FRA_DST]       = { .len = sizeof(struct in6_addr) },
 136 };
 137
 138 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 139                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 140                                struct nlattr **tb)
 141 {
 142         int err = -EINVAL;
 143         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 144
 145         if (frh->src_len > 128 || frh->dst_len > 128)
 146                 goto errout;
 147
 148         if (rule->action == FR_ACT_TO_TBL) {
 149                 if (rule->table == RT6_TABLE_UNSPEC)
 150                         goto errout;
 151
 152                 if (fib6_new_table(rule->table) == NULL) {
 153                         err = -ENOBUFS;
 154                         goto errout;
 155                 }
 156         }
 157
 158         if (tb[FRA_SRC])
 159                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 160                            sizeof(struct in6_addr));
 161
 162         if (tb[FRA_DST])
 163                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 164                            sizeof(struct in6_addr));
 165
 166         rule6->src.plen = frh->src_len;
 167         rule6->dst.plen = frh->dst_len;
 168         rule6->tclass = frh->tos;
 169
 170         err = 0;
 171 errout:
 172         return err;
 173 }
 174
 175 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 176                              struct nlattr **tb)
 177 {
 178         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 179
 180         if (frh->src_len && (rule6->src.plen != frh->src_len))
 181                 return 0;
 182
 183         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 184                 return 0;
 185
 186         if (frh->tos && (rule6->tclass != frh->tos))
 187                 return 0;
 188
 189         if (tb[FRA_SRC] &&
 190             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 191                 return 0;
 192
 193         if (tb[FRA_DST] &&
 194             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 195                 return 0;
 196
 197         return 1;
 198 }
 199
 200 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 201                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 202 {
 203         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 204
 205         frh->family = AF_INET6;
 206         frh->dst_len = rule6->dst.plen;
 207         frh->src_len = rule6->src.plen;
 208         frh->tos = rule6->tclass;
 209
 210         if (rule6->dst.plen)
 211                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 212                         &rule6->dst.addr);
 213
 214         if (rule6->src.plen)
 215                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 216                         &rule6->src.addr);
 217
 218         return 0;
 219
 220 nla_put_failure:
 221         return -ENOBUFS;
 222 }
 223
 224 int fib6_rules_dump(struct sk_buff *skb, struct netlink_callback *cb)
 225 {
 226         return fib_rules_dump(skb, cb, AF_INET6);
 227 }
 228
 229 static u32 fib6_rule_default_pref(void)
 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 struct fib_rules_ops fib6_rules_ops = {
 241         .family                 = AF_INET6,
 242         .rule_size              = sizeof(struct fib6_rule),
 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         .rules_list             = &fib6_rules,
 253         .owner                  = THIS_MODULE,
 254 };
 255
 256 void __init fib6_rules_init(void)
 257 {
 258         list_add_tail(&local_rule.common.list, &fib6_rules);
 259         list_add_tail(&main_rule.common.list, &fib6_rules);
 260
 261         fib_rules_register(&fib6_rules_ops);
 262 }
 263
 264 void fib6_rules_cleanup(void)
 265 {
 266         fib_rules_unregister(&fib6_rules_ops);
 267 }