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/ip6_route.h>
  21 #include <net/netlink.h>
  22
  23 struct fib6_rule
  24 {
  25         struct fib_rule         common;
  26         struct rt6key           src;
  27         struct rt6key           dst;
  28 #ifdef CONFIG_IPV6_ROUTE_FWMARK
  29         u32                     fwmark;
  30         u32                     fwmask;
  31 #endif
  32         u8                      tclass;
  33 };
  34
  35 static struct fib_rules_ops fib6_rules_ops;
  36
  37 static struct fib6_rule main_rule = {
  38         .common = {
  39                 .refcnt =       ATOMIC_INIT(2),
  40                 .pref =         0x7FFE,
  41                 .action =       FR_ACT_TO_TBL,
  42                 .table =        RT6_TABLE_MAIN,
  43         },
  44 };
  45
  46 static struct fib6_rule local_rule = {
  47         .common = {
  48                 .refcnt =       ATOMIC_INIT(2),
  49                 .pref =         0,
  50                 .action =       FR_ACT_TO_TBL,
  51                 .table =        RT6_TABLE_LOCAL,
  52                 .flags =        FIB_RULE_PERMANENT,
  53         },
  54 };
  55
  56 static LIST_HEAD(fib6_rules);
  57
  58 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
  59                                    pol_lookup_t lookup)
  60 {
  61         struct fib_lookup_arg arg = {
  62                 .lookup_ptr = lookup,
  63         };
  64
  65         fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
  66         if (arg.rule)
  67                 fib_rule_put(arg.rule);
  68
  69         if (arg.result)
  70                 return (struct dst_entry *) arg.result;
  71
  72         dst_hold(&ip6_null_entry.u.dst);
  73         return &ip6_null_entry.u.dst;
  74 }
  75
  76 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  77                             int flags, struct fib_lookup_arg *arg)
  78 {
  79         struct rt6_info *rt = NULL;
  80         struct fib6_table *table;
  81         pol_lookup_t lookup = arg->lookup_ptr;
  82
  83         switch (rule->action) {
  84         case FR_ACT_TO_TBL:
  85                 break;
  86         case FR_ACT_UNREACHABLE:
  87                 rt = &ip6_null_entry;
  88                 goto discard_pkt;
  89         default:
  90         case FR_ACT_BLACKHOLE:
  91                 rt = &ip6_blk_hole_entry;
  92                 goto discard_pkt;
  93         case FR_ACT_PROHIBIT:
  94                 rt = &ip6_prohibit_entry;
  95                 goto discard_pkt;
  96         }
  97
  98         table = fib6_get_table(rule->table);
  99         if (table)
 100                 rt = lookup(table, flp, flags);
 101
 102         if (rt != &ip6_null_entry)
 103                 goto out;
 104         dst_release(&rt->u.dst);
 105         rt = NULL;
 106         goto out;
 107
 108 discard_pkt:
 109         dst_hold(&rt->u.dst);
 110 out:
 111         arg->result = rt;
 112         return rt == NULL ? -EAGAIN : 0;
 113 }
 114
 115
 116 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 117 {
 118         struct fib6_rule *r = (struct fib6_rule *) rule;
 119
 120         if (r->dst.plen &&
 121             !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 122                 return 0;
 123
 124         if (r->src.plen) {
 125                 if (!(flags & RT6_LOOKUP_F_HAS_SADDR) ||
 126                     !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
 127                         return 0;
 128         }
 129
 130         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 131                 return 0;
 132
 133 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 134         if ((r->fwmark ^ fl->fl6_fwmark) & r->fwmask)
 135                 return 0;
 136 #endif
 137
 138         return 1;
 139 }
 140
 141 static struct nla_policy fib6_rule_policy[FRA_MAX+1] __read_mostly = {
 142         [FRA_IFNAME]    = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
 143         [FRA_PRIORITY]  = { .type = NLA_U32 },
 144         [FRA_SRC]       = { .len = sizeof(struct in6_addr) },
 145         [FRA_DST]       = { .len = sizeof(struct in6_addr) },
 146         [FRA_FWMARK]    = { .type = NLA_U32 },
 147         [FRA_FWMASK]    = { .type = NLA_U32 },
 148         [FRA_TABLE]     = { .type = NLA_U32 },
 149 };
 150
 151 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 152                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 153                                struct nlattr **tb)
 154 {
 155         int err = -EINVAL;
 156         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 157
 158         if (frh->src_len > 128 || frh->dst_len > 128 ||
 159             (frh->tos & ~IPV6_FLOWINFO_MASK))
 160                 goto errout;
 161
 162         if (rule->action == FR_ACT_TO_TBL) {
 163                 if (rule->table == RT6_TABLE_UNSPEC)
 164                         goto errout;
 165
 166                 if (fib6_new_table(rule->table) == NULL) {
 167                         err = -ENOBUFS;
 168                         goto errout;
 169                 }
 170         }
 171
 172         if (tb[FRA_SRC])
 173                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 174                            sizeof(struct in6_addr));
 175
 176         if (tb[FRA_DST])
 177                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 178                            sizeof(struct in6_addr));
 179
 180 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 181         if (tb[FRA_FWMARK]) {
 182                 rule6->fwmark = nla_get_u32(tb[FRA_FWMARK]);
 183                 if (rule6->fwmark) {
 184                         /*
 185                          * if the mark value is non-zero,
 186                          * all bits are compared by default
 187                          * unless a mask is explicitly specified.
 188                          */
 189                         rule6->fwmask = 0xFFFFFFFF;
 190                 }
 191         }
 192
 193         if (tb[FRA_FWMASK])
 194                 rule6->fwmask = nla_get_u32(tb[FRA_FWMASK]);
 195 #endif
 196
 197         rule6->src.plen = frh->src_len;
 198         rule6->dst.plen = frh->dst_len;
 199         rule6->tclass = frh->tos;
 200
 201         err = 0;
 202 errout:
 203         return err;
 204 }
 205
 206 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 207                              struct nlattr **tb)
 208 {
 209         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 210
 211         if (frh->src_len && (rule6->src.plen != frh->src_len))
 212                 return 0;
 213
 214         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 215                 return 0;
 216
 217         if (frh->tos && (rule6->tclass != frh->tos))
 218                 return 0;
 219
 220         if (tb[FRA_SRC] &&
 221             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 222                 return 0;
 223
 224         if (tb[FRA_DST] &&
 225             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 226                 return 0;
 227
 228 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 229         if (tb[FRA_FWMARK] && (rule6->fwmark != nla_get_u32(tb[FRA_FWMARK])))
 230                 return 0;
 231
 232         if (tb[FRA_FWMASK] && (rule6->fwmask != nla_get_u32(tb[FRA_FWMASK])))
 233                 return 0;
 234 #endif
 235
 236         return 1;
 237 }
 238
 239 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 240                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 241 {
 242         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 243
 244         frh->family = AF_INET6;
 245         frh->dst_len = rule6->dst.plen;
 246         frh->src_len = rule6->src.plen;
 247         frh->tos = rule6->tclass;
 248
 249         if (rule6->dst.plen)
 250                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 251                         &rule6->dst.addr);
 252
 253         if (rule6->src.plen)
 254                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 255                         &rule6->src.addr);
 256
 257 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 258         if (rule6->fwmark)
 259                 NLA_PUT_U32(skb, FRA_FWMARK, rule6->fwmark);
 260
 261         if (rule6->fwmask || rule6->fwmark)
 262                 NLA_PUT_U32(skb, FRA_FWMASK, rule6->fwmask);
 263 #endif
 264
 265         return 0;
 266
 267 nla_put_failure:
 268         return -ENOBUFS;
 269 }
 270
 271 int fib6_rules_dump(struct sk_buff *skb, struct netlink_callback *cb)
 272 {
 273         return fib_rules_dump(skb, cb, AF_INET6);
 274 }
 275
 276 static u32 fib6_rule_default_pref(void)
 277 {
 278         return 0x3FFF;
 279 }
 280
 281 static struct fib_rules_ops fib6_rules_ops = {
 282         .family                 = AF_INET6,
 283         .rule_size              = sizeof(struct fib6_rule),
 284         .action                 = fib6_rule_action,
 285         .match                  = fib6_rule_match,
 286         .configure              = fib6_rule_configure,
 287         .compare                = fib6_rule_compare,
 288         .fill                   = fib6_rule_fill,
 289         .default_pref           = fib6_rule_default_pref,
 290         .nlgroup                = RTNLGRP_IPV6_RULE,
 291         .policy                 = fib6_rule_policy,
 292         .rules_list             = &fib6_rules,
 293         .owner                  = THIS_MODULE,
 294 };
 295
 296 void __init fib6_rules_init(void)
 297 {
 298         list_add_tail(&local_rule.common.list, &fib6_rules);
 299         list_add_tail(&main_rule.common.list, &fib6_rules);
 300
 301         fib_rules_register(&fib6_rules_ops);
 302 }
 303
 304 void fib6_rules_cleanup(void)
 305 {
 306         fib_rules_unregister(&fib6_rules_ops);
 307 }