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 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         if (arg.result)
  67                 return arg.result;
  68
  69         dst_hold(&ip6_null_entry.u.dst);
  70         return &ip6_null_entry.u.dst;
  71 }
  72
  73 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  74                             int flags, struct fib_lookup_arg *arg)
  75 {
  76         struct rt6_info *rt = NULL;
  77         struct fib6_table *table;
  78         pol_lookup_t lookup = arg->lookup_ptr;
  79
  80         switch (rule->action) {
  81         case FR_ACT_TO_TBL:
  82                 break;
  83         case FR_ACT_UNREACHABLE:
  84                 rt = &ip6_null_entry;
  85                 goto discard_pkt;
  86         default:
  87         case FR_ACT_BLACKHOLE:
  88                 rt = &ip6_blk_hole_entry;
  89                 goto discard_pkt;
  90         case FR_ACT_PROHIBIT:
  91                 rt = &ip6_prohibit_entry;
  92                 goto discard_pkt;
  93         }
  94
  95         table = fib6_get_table(rule->table);
  96         if (table)
  97                 rt = lookup(table, flp, flags);
  98
  99         if (rt != &ip6_null_entry) {
 100                 struct fib6_rule *r = (struct fib6_rule *)rule;
 101
 102                 /*
 103                  * If we need to find a source address for this traffic,
 104                  * we check the result if it meets requirement of the rule.
 105                  */
 106                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
 107                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
 108                         struct in6_addr saddr;
 109                         if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst,
 110                                            &saddr))
 111                                 goto again;
 112                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
 113                                                r->src.plen))
 114                                 goto again;
 115                         ipv6_addr_copy(&flp->fl6_src, &saddr);
 116                 }
 117                 goto out;
 118         }
 119 again:
 120         dst_release(&rt->u.dst);
 121         rt = NULL;
 122         goto out;
 123
 124 discard_pkt:
 125         dst_hold(&rt->u.dst);
 126 out:
 127         arg->result = rt;
 128         return rt == NULL ? -EAGAIN : 0;
 129 }
 130
 131
 132 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 133 {
 134         struct fib6_rule *r = (struct fib6_rule *) rule;
 135
 136         if (r->dst.plen &&
 137             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 138                 return 0;
 139
 140         /*
 141          * If FIB_RULE_FIND_SADDR is set and we do not have a
 142          * source address for the traffic, we defer check for
 143          * source address.
 144          */
 145         if (r->src.plen) {
 146                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 147                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 148                                                r->src.plen))
 149                                 return 0;
 150                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 151                         return 0;
 152         }
 153
 154         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 155                 return 0;
 156
 157         return 1;
 158 }
 159
 160 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 161         FRA_GENERIC_POLICY,
 162 };
 163
 164 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 165                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 166                                struct nlattr **tb)
 167 {
 168         int err = -EINVAL;
 169         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 170
 171         if (rule->action == FR_ACT_TO_TBL) {
 172                 if (rule->table == RT6_TABLE_UNSPEC)
 173                         goto errout;
 174
 175                 if (fib6_new_table(rule->table) == NULL) {
 176                         err = -ENOBUFS;
 177                         goto errout;
 178                 }
 179         }
 180
 181         if (frh->src_len)
 182                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 183                            sizeof(struct in6_addr));
 184
 185         if (frh->dst_len)
 186                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 187                            sizeof(struct in6_addr));
 188
 189         rule6->src.plen = frh->src_len;
 190         rule6->dst.plen = frh->dst_len;
 191         rule6->tclass = frh->tos;
 192
 193         err = 0;
 194 errout:
 195         return err;
 196 }
 197
 198 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 199                              struct nlattr **tb)
 200 {
 201         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 202
 203         if (frh->src_len && (rule6->src.plen != frh->src_len))
 204                 return 0;
 205
 206         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 207                 return 0;
 208
 209         if (frh->tos && (rule6->tclass != frh->tos))
 210                 return 0;
 211
 212         if (frh->src_len &&
 213             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 214                 return 0;
 215
 216         if (frh->dst_len &&
 217             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 218                 return 0;
 219
 220         return 1;
 221 }
 222
 223 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 224                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 225 {
 226         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 227
 228         frh->family = AF_INET6;
 229         frh->dst_len = rule6->dst.plen;
 230         frh->src_len = rule6->src.plen;
 231         frh->tos = rule6->tclass;
 232
 233         if (rule6->dst.plen)
 234                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 235                         &rule6->dst.addr);
 236
 237         if (rule6->src.plen)
 238                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 239                         &rule6->src.addr);
 240
 241         return 0;
 242
 243 nla_put_failure:
 244         return -ENOBUFS;
 245 }
 246
 247 static u32 fib6_rule_default_pref(void)
 248 {
 249         return 0x3FFF;
 250 }
 251
 252 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 253 {
 254         return nla_total_size(16) /* dst */
 255                + nla_total_size(16); /* src */
 256 }
 257
 258 static struct fib_rules_ops fib6_rules_ops = {
 259         .family                 = AF_INET6,
 260         .rule_size              = sizeof(struct fib6_rule),
 261         .addr_size              = sizeof(struct in6_addr),
 262         .action                 = fib6_rule_action,
 263         .match                  = fib6_rule_match,
 264         .configure              = fib6_rule_configure,
 265         .compare                = fib6_rule_compare,
 266         .fill                   = fib6_rule_fill,
 267         .default_pref           = fib6_rule_default_pref,
 268         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 269         .nlgroup                = RTNLGRP_IPV6_RULE,
 270         .policy                 = fib6_rule_policy,
 271         .rules_list             = &fib6_rules,
 272         .owner                  = THIS_MODULE,
 273 };
 274
 275 void __init fib6_rules_init(void)
 276 {
 277         list_add_tail(&local_rule.common.list, &fib6_rules);
 278         list_add_tail(&main_rule.common.list, &fib6_rules);
 279
 280         fib_rules_register(&fib6_rules_ops);
 281 }
 282
 283 void fib6_rules_cleanup(void)
 284 {
 285         fib_rules_unregister(&fib6_rules_ops);
 286 }