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