release/src-rt-6.x/linux/linux-2.6/net/ipv4/fib_rules.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              IPv4 Forwarding Information Base: policy rules.
   7  *
   8  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   9  *              Thomas Graf <tgraf@suug.ch>
  10  *
  11  *              This program is free software; you can redistribute it and/or
  12  *              modify it under the terms of the GNU General Public License
  13  *              as published by the Free Software Foundation; either version
  14  *              2 of the License, or (at your option) any later version.
  15  *
  16  * Fixes:
  17  *              Rani Assaf      :       local_rule cannot be deleted
  18  *              Marc Boucher    :       routing by fwmark
  19  */
  20
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/netlink.h>
  25 #include <linux/inetdevice.h>
  26 #include <linux/init.h>
  27 #include <linux/list.h>
  28 #include <linux/rcupdate.h>
  29 #include <net/ip.h>
  30 #include <net/route.h>
  31 #include <net/tcp.h>
  32 #include <net/ip_fib.h>
  33 #include <net/fib_rules.h>
  34
  35 static struct fib_rules_ops fib4_rules_ops;
  36
  37 struct fib4_rule
  38 {
  39         struct fib_rule         common;
  40         u8                      dst_len;
  41         u8                      src_len;
  42         u8                      tos;
  43         __be32                  src;
  44         __be32                  srcmask;
  45         __be32                  dst;
  46         __be32                  dstmask;
  47 #ifdef CONFIG_NET_CLS_ROUTE
  48         u32                     tclassid;
  49 #endif
  50 };
  51
  52 #ifdef CONFIG_NET_CLS_ROUTE
  53 u32 fib_rules_tclass(struct fib_result *res)
  54 {
  55         return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;
  56 }
  57 #endif
  58
  59 int fib_lookup(struct flowi *flp, struct fib_result *res)
  60 {
  61         struct fib_lookup_arg arg = {
  62                 .result = res,
  63         };
  64         int err;
  65
  66         err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg);
  67         res->r = arg.rule;
  68
  69         return err;
  70 }
  71
  72 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
  73                             int flags, struct fib_lookup_arg *arg)
  74 {
  75         int err = -EAGAIN;
  76         struct fib_table *tbl;
  77
  78         switch (rule->action) {
  79         case FR_ACT_TO_TBL:
  80                 break;
  81
  82         case FR_ACT_UNREACHABLE:
  83                 err = -ENETUNREACH;
  84                 goto errout;
  85
  86         case FR_ACT_PROHIBIT:
  87                 err = -EACCES;
  88                 goto errout;
  89
  90         case FR_ACT_BLACKHOLE:
  91         default:
  92                 err = -EINVAL;
  93                 goto errout;
  94         }
  95
  96         if ((tbl = fib_get_table(rule->table)) == NULL)
  97                 goto errout;
  98
  99         err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result);
 100         if (err > 0)
 101                 err = -EAGAIN;
 102 errout:
 103         return err;
 104 }
 105
 106
 107 void fib_select_default(const struct flowi *flp, struct fib_result *res)
 108 {
 109         if (res->r && res->r->action == FR_ACT_TO_TBL &&
 110             FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {
 111                 struct fib_table *tb;
 112                 if ((tb = fib_get_table(res->r->table)) != NULL)
 113                         tb->tb_select_default(tb, flp, res);
 114         }
 115 }
 116
 117 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 118 {
 119         struct fib4_rule *r = (struct fib4_rule *) rule;
 120         __be32 daddr = fl->fl4_dst;
 121         __be32 saddr = fl->fl4_src;
 122
 123         if (((saddr ^ r->src) & r->srcmask) ||
 124             ((daddr ^ r->dst) & r->dstmask))
 125                 return 0;
 126
 127         if (r->tos && (r->tos != fl->fl4_tos))
 128                 return 0;
 129
 130         return 1;
 131 }
 132
 133 static struct fib_table *fib_empty_table(void)
 134 {
 135         u32 id;
 136
 137         for (id = 1; id <= RT_TABLE_MAX; id++)
 138                 if (fib_get_table(id) == NULL)
 139                         return fib_new_table(id);
 140         return NULL;
 141 }
 142
 143 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
 144         FRA_GENERIC_POLICY,
 145         [FRA_FLOW]      = { .type = NLA_U32 },
 146 };
 147
 148 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 149                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 150                                struct nlattr **tb)
 151 {
 152         int err = -EINVAL;
 153         struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 154
 155         if (frh->tos & ~IPTOS_TOS_MASK)
 156                 goto errout;
 157
 158         if (rule->table == RT_TABLE_UNSPEC) {
 159                 if (rule->action == FR_ACT_TO_TBL) {
 160                         struct fib_table *table;
 161
 162                         table = fib_empty_table();
 163                         if (table == NULL) {
 164                                 err = -ENOBUFS;
 165                                 goto errout;
 166                         }
 167
 168                         rule->table = table->tb_id;
 169                 }
 170         }
 171
 172         if (frh->src_len)
 173                 rule4->src = nla_get_be32(tb[FRA_SRC]);
 174
 175         if (frh->dst_len)
 176                 rule4->dst = nla_get_be32(tb[FRA_DST]);
 177
 178 #ifdef CONFIG_NET_CLS_ROUTE
 179         if (tb[FRA_FLOW])
 180                 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
 181 #endif
 182
 183         rule4->src_len = frh->src_len;
 184         rule4->srcmask = inet_make_mask(rule4->src_len);
 185         rule4->dst_len = frh->dst_len;
 186         rule4->dstmask = inet_make_mask(rule4->dst_len);
 187         rule4->tos = frh->tos;
 188
 189         err = 0;
 190 errout:
 191         return err;
 192 }
 193
 194 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 195                              struct nlattr **tb)
 196 {
 197         struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 198
 199         if (frh->src_len && (rule4->src_len != frh->src_len))
 200                 return 0;
 201
 202         if (frh->dst_len && (rule4->dst_len != frh->dst_len))
 203                 return 0;
 204
 205         if (frh->tos && (rule4->tos != frh->tos))
 206                 return 0;
 207
 208 #ifdef CONFIG_NET_CLS_ROUTE
 209         if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
 210                 return 0;
 211 #endif
 212
 213         if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))
 214                 return 0;
 215
 216         if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))
 217                 return 0;
 218
 219         return 1;
 220 }
 221
 222 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 223                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 224 {
 225         struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 226
 227         frh->family = AF_INET;
 228         frh->dst_len = rule4->dst_len;
 229         frh->src_len = rule4->src_len;
 230         frh->tos = rule4->tos;
 231
 232         if (rule4->dst_len)
 233                 NLA_PUT_BE32(skb, FRA_DST, rule4->dst);
 234
 235         if (rule4->src_len)
 236                 NLA_PUT_BE32(skb, FRA_SRC, rule4->src);
 237
 238 #ifdef CONFIG_NET_CLS_ROUTE
 239         if (rule4->tclassid)
 240                 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);
 241 #endif
 242         return 0;
 243
 244 nla_put_failure:
 245         return -ENOBUFS;
 246 }
 247
 248 static u32 fib4_rule_default_pref(void)
 249 {
 250         struct list_head *pos;
 251         struct fib_rule *rule;
 252
 253         if (!list_empty(&fib4_rules_ops.rules_list)) {
 254                 pos = fib4_rules_ops.rules_list.next;
 255                 if (pos->next != &fib4_rules_ops.rules_list) {
 256                         rule = list_entry(pos->next, struct fib_rule, list);
 257                         if (rule->pref)
 258                                 return rule->pref - 1;
 259                 }
 260         }
 261
 262         return 0;
 263 }
 264
 265 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
 266 {
 267         return nla_total_size(4) /* dst */
 268                + nla_total_size(4) /* src */
 269                + nla_total_size(4); /* flow */
 270 }
 271
 272 static void fib4_rule_flush_cache(void)
 273 {
 274         rt_cache_flush(-1);
 275 }
 276
 277 static struct fib_rules_ops fib4_rules_ops = {
 278         .family         = AF_INET,
 279         .rule_size      = sizeof(struct fib4_rule),
 280         .addr_size      = sizeof(u32),
 281         .action         = fib4_rule_action,
 282         .match          = fib4_rule_match,
 283         .configure      = fib4_rule_configure,
 284         .compare        = fib4_rule_compare,
 285         .fill           = fib4_rule_fill,
 286         .default_pref   = fib4_rule_default_pref,
 287         .nlmsg_payload  = fib4_rule_nlmsg_payload,
 288         .flush_cache    = fib4_rule_flush_cache,
 289         .nlgroup        = RTNLGRP_IPV4_RULE,
 290         .policy         = fib4_rule_policy,
 291         .rules_list     = LIST_HEAD_INIT(fib4_rules_ops.rules_list),
 292         .owner          = THIS_MODULE,
 293 };
 294
 295 static int __init fib_default_rules_init(void)
 296 {
 297         int err;
 298
 299         err = fib_default_rule_add(&fib4_rules_ops, 0,
 300                                    RT_TABLE_LOCAL, FIB_RULE_PERMANENT);
 301         if (err < 0)
 302                 return err;
 303         err = fib_default_rule_add(&fib4_rules_ops, 0x7FFE,
 304                                    RT_TABLE_MAIN, 0);
 305         if (err < 0)
 306                 return err;
 307         err = fib_default_rule_add(&fib4_rules_ops, 0x7FFF,
 308                                    RT_TABLE_DEFAULT, 0);
 309         if (err < 0)
 310                 return err;
 311         return 0;
 312 }
 313
 314 void __init fib4_rules_init(void)
 315 {
 316         BUG_ON(fib_default_rules_init());
 317         fib_rules_register(&fib4_rules_ops);
 318 }