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   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 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi *fl,
  33                                    int flags, pol_lookup_t lookup)
  34 {
  35         struct fib_lookup_arg arg = {
  36                 .lookup_ptr = lookup,
  37         };
  38
  39         fib_rules_lookup(net->ipv6.fib6_rules_ops, fl, flags, &arg);
  40         if (arg.rule)
  41                 fib_rule_put(arg.rule);
  42
  43         if (arg.result)
  44                 return arg.result;
  45
  46         dst_hold(&net->ipv6.ip6_null_entry->u.dst);
  47         return &net->ipv6.ip6_null_entry->u.dst;
  48 }
  49
  50 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  51                             int flags, struct fib_lookup_arg *arg)
  52 {
  53         struct rt6_info *rt = NULL;
  54         struct fib6_table *table;
  55         struct net *net = rule->fr_net;
  56         pol_lookup_t lookup = arg->lookup_ptr;
  57
  58         switch (rule->action) {
  59         case FR_ACT_TO_TBL:
  60                 break;
  61         case FR_ACT_UNREACHABLE:
  62                 rt = net->ipv6.ip6_null_entry;
  63                 goto discard_pkt;
  64         default:
  65         case FR_ACT_BLACKHOLE:
  66                 rt = net->ipv6.ip6_blk_hole_entry;
  67                 goto discard_pkt;
  68         case FR_ACT_PROHIBIT:
  69                 rt = net->ipv6.ip6_prohibit_entry;
  70                 goto discard_pkt;
  71         }
  72
  73         table = fib6_get_table(net, rule->table);
  74         if (table)
  75                 rt = lookup(net, table, flp, flags);
  76
  77         if (rt != net->ipv6.ip6_null_entry) {
  78                 struct fib6_rule *r = (struct fib6_rule *)rule;
  79
  80                 /*
  81                  * If we need to find a source address for this traffic,
  82                  * we check the result if it meets requirement of the rule.
  83                  */
  84                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  85                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  86                         struct in6_addr saddr;
  87                         unsigned int srcprefs = 0;
  88
  89                         if (flags & RT6_LOOKUP_F_SRCPREF_TMP)
  90                                 srcprefs |= IPV6_PREFER_SRC_TMP;
  91                         if (flags & RT6_LOOKUP_F_SRCPREF_PUBLIC)
  92                                 srcprefs |= IPV6_PREFER_SRC_PUBLIC;
  93                         if (flags & RT6_LOOKUP_F_SRCPREF_COA)
  94                                 srcprefs |= IPV6_PREFER_SRC_COA;
  95
  96                         if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
  97                                                &flp->fl6_dst, srcprefs,
  98                                                &saddr))
  99                                 goto again;
 100                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
 101                                                r->src.plen))
 102                                 goto again;
 103                         ipv6_addr_copy(&flp->fl6_src, &saddr);
 104                 }
 105                 goto out;
 106         }
 107 again:
 108         dst_release(&rt->u.dst);
 109         rt = NULL;
 110         goto out;
 111
 112 discard_pkt:
 113         dst_hold(&rt->u.dst);
 114 out:
 115         arg->result = rt;
 116         return rt == NULL ? -EAGAIN : 0;
 117 }
 118
 119
 120 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 121 {
 122         struct fib6_rule *r = (struct fib6_rule *) rule;
 123
 124         if (r->dst.plen &&
 125             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 126                 return 0;
 127
 128         /*
 129          * If FIB_RULE_FIND_SADDR is set and we do not have a
 130          * source address for the traffic, we defer check for
 131          * source address.
 132          */
 133         if (r->src.plen) {
 134                 if (flags & RT6_LOOKUP_F_HAS_SADDR) {
 135                         if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
 136                                                r->src.plen))
 137                                 return 0;
 138                 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
 139                         return 0;
 140         }
 141
 142         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 143                 return 0;
 144
 145         return 1;
 146 }
 147
 148 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 149         FRA_GENERIC_POLICY,
 150 };
 151
 152 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 153                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 154                                struct nlattr **tb)
 155 {
 156         int err = -EINVAL;
 157         struct net *net = sock_net(skb->sk);
 158         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 159
 160         if (rule->action == FR_ACT_TO_TBL) {
 161                 if (rule->table == RT6_TABLE_UNSPEC)
 162                         goto errout;
 163
 164                 if (fib6_new_table(net, rule->table) == NULL) {
 165                         err = -ENOBUFS;
 166                         goto errout;
 167                 }
 168         }
 169
 170         if (frh->src_len)
 171                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 172                            sizeof(struct in6_addr));
 173
 174         if (frh->dst_len)
 175                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 176                            sizeof(struct in6_addr));
 177
 178         rule6->src.plen = frh->src_len;
 179         rule6->dst.plen = frh->dst_len;
 180         rule6->tclass = frh->tos;
 181
 182         err = 0;
 183 errout:
 184         return err;
 185 }
 186
 187 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 188                              struct nlattr **tb)
 189 {
 190         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 191
 192         if (frh->src_len && (rule6->src.plen != frh->src_len))
 193                 return 0;
 194
 195         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 196                 return 0;
 197
 198         if (frh->tos && (rule6->tclass != frh->tos))
 199                 return 0;
 200
 201         if (frh->src_len &&
 202             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 203                 return 0;
 204
 205         if (frh->dst_len &&
 206             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 207                 return 0;
 208
 209         return 1;
 210 }
 211
 212 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 213                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 214 {
 215         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 216
 217         frh->family = AF_INET6;
 218         frh->dst_len = rule6->dst.plen;
 219         frh->src_len = rule6->src.plen;
 220         frh->tos = rule6->tclass;
 221
 222         if (rule6->dst.plen)
 223                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 224                         &rule6->dst.addr);
 225
 226         if (rule6->src.plen)
 227                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 228                         &rule6->src.addr);
 229
 230         return 0;
 231
 232 nla_put_failure:
 233         return -ENOBUFS;
 234 }
 235
 236 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)
 237 {
 238         return 0x3FFF;
 239 }
 240
 241 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
 242 {
 243         return nla_total_size(16) /* dst */
 244                + nla_total_size(16); /* src */
 245 }
 246
 247 static struct fib_rules_ops fib6_rules_ops_template = {
 248         .family                 = AF_INET6,
 249         .rule_size              = sizeof(struct fib6_rule),
 250         .addr_size              = sizeof(struct in6_addr),
 251         .action                 = fib6_rule_action,
 252         .match                  = fib6_rule_match,
 253         .configure              = fib6_rule_configure,
 254         .compare                = fib6_rule_compare,
 255         .fill                   = fib6_rule_fill,
 256         .default_pref           = fib6_rule_default_pref,
 257         .nlmsg_payload          = fib6_rule_nlmsg_payload,
 258         .nlgroup                = RTNLGRP_IPV6_RULE,
 259         .policy                 = fib6_rule_policy,
 260         .owner                  = THIS_MODULE,
 261         .fro_net                = &init_net,
 262 };
 263
 264 static int fib6_rules_net_init(struct net *net)
 265 {
 266         int err = -ENOMEM;
 267
 268         net->ipv6.fib6_rules_ops = kmemdup(&fib6_rules_ops_template,
 269                                            sizeof(*net->ipv6.fib6_rules_ops),
 270                                            GFP_KERNEL);
 271         if (!net->ipv6.fib6_rules_ops)
 272                 goto out;
 273
 274         net->ipv6.fib6_rules_ops->fro_net = net;
 275         INIT_LIST_HEAD(&net->ipv6.fib6_rules_ops->rules_list);
 276
 277         err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 278                                    RT6_TABLE_LOCAL, FIB_RULE_PERMANENT);
 279         if (err)
 280                 goto out_fib6_rules_ops;
 281
 282         err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
 283                                    0x7FFE, RT6_TABLE_MAIN, 0);
 284         if (err)
 285                 goto out_fib6_default_rule_add;
 286
 287         err = fib_rules_register(net->ipv6.fib6_rules_ops);
 288         if (err)
 289                 goto out_fib6_default_rule_add;
 290 out:
 291         return err;
 292
 293 out_fib6_default_rule_add:
 294         fib_rules_cleanup_ops(net->ipv6.fib6_rules_ops);
 295 out_fib6_rules_ops:
 296         kfree(net->ipv6.fib6_rules_ops);
 297         goto out;
 298 }
 299
 300 static void fib6_rules_net_exit(struct net *net)
 301 {
 302         fib_rules_unregister(net->ipv6.fib6_rules_ops);
 303         kfree(net->ipv6.fib6_rules_ops);
 304 }
 305
 306 static struct pernet_operations fib6_rules_net_ops = {
 307         .init = fib6_rules_net_init,
 308         .exit = fib6_rules_net_exit,
 309 };
 310
 311 int __init fib6_rules_init(void)
 312 {
 313         return register_pernet_subsys(&fib6_rules_net_ops);
 314 }
 315
 316
 317 void fib6_rules_cleanup(void)
 318 {
 319         unregister_pernet_subsys(&fib6_rules_net_ops);
 320 }