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/config.h>
  17 #include <linux/netdevice.h>
  18
  19 #include <net/fib_rules.h>
  20 #include <net/ipv6.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 static LIST_HEAD(fib6_rules);
  54
  55 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
  56                                    pol_lookup_t lookup)
  57 {
  58         struct fib_lookup_arg arg = {
  59                 .lookup_ptr = lookup,
  60         };
  61
  62         fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
  63         if (arg.rule)
  64                 fib_rule_put(arg.rule);
  65
  66         return (struct dst_entry *) arg.result;
  67 }
  68
  69 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  70                             int flags, struct fib_lookup_arg *arg)
  71 {
  72         struct rt6_info *rt = NULL;
  73         struct fib6_table *table;
  74         pol_lookup_t lookup = arg->lookup_ptr;
  75
  76         switch (rule->action) {
  77         case FR_ACT_TO_TBL:
  78                 break;
  79         case FR_ACT_UNREACHABLE:
  80                 rt = &ip6_null_entry;
  81                 goto discard_pkt;
  82         default:
  83         case FR_ACT_BLACKHOLE:
  84                 rt = &ip6_blk_hole_entry;
  85                 goto discard_pkt;
  86         case FR_ACT_PROHIBIT:
  87                 rt = &ip6_prohibit_entry;
  88                 goto discard_pkt;
  89         }
  90
  91         table = fib6_get_table(rule->table);
  92         if (table)
  93                 rt = lookup(table, flp, flags);
  94
  95         if (rt != &ip6_null_entry)
  96                 goto out;
  97         dst_release(&rt->u.dst);
  98         rt = NULL;
  99         goto out;
 100
 101 discard_pkt:
 102         dst_hold(&rt->u.dst);
 103 out:
 104         arg->result = rt;
 105         return rt == NULL ? -EAGAIN : 0;
 106 }
 107
 108
 109 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 110 {
 111         struct fib6_rule *r = (struct fib6_rule *) rule;
 112
 113         if (!ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 114                 return 0;
 115
 116         if ((flags & RT6_F_HAS_SADDR) &&
 117             !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
 118                 return 0;
 119
 120         return 1;
 121 }
 122
 123 static struct nla_policy fib6_rule_policy[RTA_MAX+1] __read_mostly = {
 124         [FRA_IFNAME]    = { .type = NLA_STRING },
 125         [FRA_PRIORITY]  = { .type = NLA_U32 },
 126         [FRA_SRC]       = { .minlen = sizeof(struct in6_addr) },
 127         [FRA_DST]       = { .minlen = sizeof(struct in6_addr) },
 128 };
 129
 130 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 131                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 132                                struct nlattr **tb)
 133 {
 134         int err = -EINVAL;
 135         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 136
 137         if (frh->src_len > 128 || frh->dst_len > 128 ||
 138             (frh->tos & ~IPV6_FLOWINFO_MASK))
 139                 goto errout;
 140
 141         if (rule->action == FR_ACT_TO_TBL) {
 142                 if (rule->table == RT6_TABLE_UNSPEC)
 143                         goto errout;
 144
 145                 if (fib6_new_table(rule->table) == NULL) {
 146                         err = -ENOBUFS;
 147                         goto errout;
 148                 }
 149         }
 150
 151         if (tb[FRA_SRC])
 152                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 153                            sizeof(struct in6_addr));
 154
 155         if (tb[FRA_DST])
 156                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 157                            sizeof(struct in6_addr));
 158
 159         rule6->src.plen = frh->src_len;
 160         rule6->dst.plen = frh->dst_len;
 161         rule6->tclass = frh->tos;
 162
 163         err = 0;
 164 errout:
 165         return err;
 166 }
 167
 168 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 169                              struct nlattr **tb)
 170 {
 171         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 172
 173         if (frh->src_len && (rule6->src.plen != frh->src_len))
 174                 return 0;
 175
 176         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 177                 return 0;
 178
 179         if (frh->tos && (rule6->tclass != frh->tos))
 180                 return 0;
 181
 182         if (tb[FRA_SRC] &&
 183             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 184                 return 0;
 185
 186         if (tb[FRA_DST] &&
 187             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 188                 return 0;
 189
 190         return 1;
 191 }
 192
 193 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 194                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 195 {
 196         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 197
 198         frh->family = AF_INET6;
 199         frh->dst_len = rule6->dst.plen;
 200         frh->src_len = rule6->src.plen;
 201         frh->tos = rule6->tclass;
 202
 203         if (rule6->dst.plen)
 204                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 205                         &rule6->dst.addr);
 206
 207         if (rule6->src.plen)
 208                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 209                         &rule6->src.addr);
 210
 211         return 0;
 212
 213 nla_put_failure:
 214         return -ENOBUFS;
 215 }
 216
 217 int fib6_rules_dump(struct sk_buff *skb, struct netlink_callback *cb)
 218 {
 219         return fib_rules_dump(skb, cb, AF_INET6);
 220 }
 221
 222 static u32 fib6_rule_default_pref(void)
 223 {
 224         return 0x3FFF;
 225 }
 226
 227 static struct fib_rules_ops fib6_rules_ops = {
 228         .family                 = AF_INET6,
 229         .rule_size              = sizeof(struct fib6_rule),
 230         .action                 = fib6_rule_action,
 231         .match                  = fib6_rule_match,
 232         .configure              = fib6_rule_configure,
 233         .compare                = fib6_rule_compare,
 234         .fill                   = fib6_rule_fill,
 235         .default_pref           = fib6_rule_default_pref,
 236         .nlgroup                = RTNLGRP_IPV6_RULE,
 237         .policy                 = fib6_rule_policy,
 238         .rules_list             = &fib6_rules,
 239         .owner                  = THIS_MODULE,
 240 };
 241
 242 void __init fib6_rules_init(void)
 243 {
 244         list_add_tail(&local_rule.common.list, &fib6_rules);
 245         list_add_tail(&main_rule.common.list, &fib6_rules);
 246
 247         fib_rules_register(&fib6_rules_ops);
 248 }
 249
 250 void fib6_rules_cleanup(void)
 251 {
 252         fib_rules_unregister(&fib6_rules_ops);
 253 }