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 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
  35                                    pol_lookup_t lookup)
  36 {
  37         struct fib_lookup_arg arg = {
  38                 .lookup_ptr = lookup,
  39         };
  40
  41         fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
  42         if (arg.rule)
  43                 fib_rule_put(arg.rule);
  44
  45         if (arg.result)
  46                 return arg.result;
  47
  48         dst_hold(&ip6_null_entry.u.dst);
  49         return &ip6_null_entry.u.dst;
  50 }
  51
  52 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  53                             int flags, struct fib_lookup_arg *arg)
  54 {
  55         struct rt6_info *rt = NULL;
  56         struct fib6_table *table;
  57         pol_lookup_t lookup = arg->lookup_ptr;
  58
  59         switch (rule->action) {
  60         case FR_ACT_TO_TBL:
  61                 break;
  62         case FR_ACT_UNREACHABLE:
  63                 rt = &ip6_null_entry;
  64                 goto discard_pkt;
  65         default:
  66         case FR_ACT_BLACKHOLE:
  67                 rt = &ip6_blk_hole_entry;
  68                 goto discard_pkt;
  69         case FR_ACT_PROHIBIT:
  70                 rt = &ip6_prohibit_entry;
  71                 goto discard_pkt;
  72         }
  73
  74         table = fib6_get_table(rule->table);
  75         if (table)
  76                 rt = lookup(table, flp, flags);
  77
  78         if (rt != &ip6_null_entry) {
  79                 struct fib6_rule *r = (struct fib6_rule *)rule;
  80
  81                 /*
  82                  * If we need to find a source address for this traffic,
  83                  * we check the result if it meets requirement of the rule.
  84                  */
  85                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  86                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  87                         struct in6_addr saddr;
  88                         if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst,
  89                                            &saddr))
  90                                 goto again;
  91                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
  92                                                r->src.plen))
  93                                 goto again;
  94                         ipv6_addr_copy(&flp->fl6_src, &saddr);
  95                 }
  96                 goto out;
  97         }
  98 again:
  99         dst_release(&rt->u.dst);
 100         rt = NULL;
 101         goto out;
 102
 103 discard_pkt:
 104         dst_hold(&rt->u.dst);
 105 out:
 106         arg->result = rt;
 107         return rt == NULL ? -EAGAIN : 0;
 108 }
 109
 110
 111 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 112 {
 113         struct fib6_rule *r = (struct fib6_rule *) rule;
 114
 115         if (r->dst.plen &&
 116             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 117                 return 0;
 118
 119         /*
 120          * If FIB_RULE_FIND_SADDR is set and we do not have a
 121          * source address for the traffic, we defer check for
 122          * source address.
 123          */
 124         if (r->src.plen) {
 125                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 126                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 127                                                r->src.plen))
 128                                 return 0;
 129                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 130                         return 0;
 131         }
 132
 133         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 134                 return 0;
 135
 136         return 1;
 137 }
 138
 139 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 140         FRA_GENERIC_POLICY,
 141 };
 142
 143 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 144                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 145                                struct nlattr **tb)
 146 {
 147         int err = -EINVAL;
 148         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 149
 150         if (rule->action == FR_ACT_TO_TBL) {
 151                 if (rule->table == RT6_TABLE_UNSPEC)
 152                         goto errout;
 153
 154                 if (fib6_new_table(rule->table) == NULL) {
 155                         err = -ENOBUFS;
 156                         goto errout;
 157                 }
 158         }
 159
 160         if (frh->src_len)
 161                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 162                            sizeof(struct in6_addr));
 163
 164         if (frh->dst_len)
 165                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 166                            sizeof(struct in6_addr));
 167
 168         rule6->src.plen = frh->src_len;
 169         rule6->dst.plen = frh->dst_len;
 170         rule6->tclass = frh->tos;
 171
 172         err = 0;
 173 errout:
 174         return err;
 175 }
 176
 177 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 178                              struct nlattr **tb)
 179 {
 180         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 181
 182         if (frh->src_len && (rule6->src.plen != frh->src_len))
 183                 return 0;
 184
 185         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 186                 return 0;
 187
 188         if (frh->tos && (rule6->tclass != frh->tos))
 189                 return 0;
 190
 191         if (frh->src_len &&
 192             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 193                 return 0;
 194
 195         if (frh->dst_len &&
 196             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 197                 return 0;
 198
 199         return 1;
 200 }
 201
 202 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 203                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 204 {
 205         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 206
 207         frh->family = AF_INET6;
 208         frh->dst_len = rule6->dst.plen;
 209         frh->src_len = rule6->src.plen;
 210         frh->tos = rule6->tclass;
 211
 212         if (rule6->dst.plen)
 213                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 214                         &rule6->dst.addr);
 215
 216         if (rule6->src.plen)
 217                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 218                         &rule6->src.addr);
 219
 220         return 0;
 221
 222 nla_put_failure:
 223         return -ENOBUFS;
 224 }
 225
 226 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 227 {
 228         return 0x3FFF;
 229 }
 230
 231 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 232 {
 233         return nla_total_size(16) /* dst */
 234                + nla_total_size(16); /* src */
 235 }
 236
 237 static struct fib_rules_ops fib6_rules_ops = {
 238         .family                 = AF_INET6,
 239         .rule_size              = sizeof(struct fib6_rule),
 240         .addr_size              = sizeof(struct in6_addr),
 241         .action                 = fib6_rule_action,
 242         .match                  = fib6_rule_match,
 243         .configure              = fib6_rule_configure,
 244         .compare                = fib6_rule_compare,
 245         .fill                   = fib6_rule_fill,
 246         .default_pref           = fib6_rule_default_pref,
 247         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 248         .nlgroup                = RTNLGRP_IPV6_RULE,
 249         .policy                 = fib6_rule_policy,
 250         .rules_list             = LIST_HEAD_INIT(fib6_rules_ops.rules_list),
 251         .owner                  = THIS_MODULE,
 252         .fro_net                = &init_net,
 253 };
 254
 255 static int __init fib6_default_rules_init(void)
 256 {
 257         int err;
 258
 259         err = fib_default_rule_add(&fib6_rules_ops, 0,
 260                                    RT6_TABLE_LOCAL, FIB_RULE_PERMANENT);
 261         if (err < 0)
 262                 return err;
 263         err = fib_default_rule_add(&fib6_rules_ops, 0x7FFE, RT6_TABLE_MAIN, 0);
 264         if (err < 0)
 265                 return err;
 266         return 0;
 267 }
 268
 269 int __init fib6_rules_init(void)
 270 {
 271         int ret;
 272
 273         ret = fib6_default_rules_init();
 274         if (ret)
 275                 goto out;
 276
 277         ret = fib_rules_register(&fib6_rules_ops);
 278         if (ret)
 279                 goto out_default_rules_init;
 280 out:
 281         return ret;
 282
 283 out_default_rules_init:
 284         fib_rules_cleanup_ops(&fib6_rules_ops);
 285         goto out;
 286 }
 287
 288 void fib6_rules_cleanup(void)
 289 {
 290         fib_rules_unregister(&fib6_rules_ops);
 291 }