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/config.h>
  17 #include <linux/netdevice.h>
  18
  19 #include <net/fib_rules.h>
  20 #include <net/ipv6.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 #ifdef CONFIG_IPV6_ROUTE_FWMARK
  30         u32                     fwmark;
  31         u32                     fwmask;
  32 #endif
  33         u8                      tclass;
  34 };
  35
  36 static struct fib_rules_ops fib6_rules_ops;
  37
  38 static struct fib6_rule main_rule = {
  39         .common = {
  40                 .refcnt =       ATOMIC_INIT(2),
  41                 .pref =         0x7FFE,
  42                 .action =       FR_ACT_TO_TBL,
  43                 .table =        RT6_TABLE_MAIN,
  44         },
  45 };
  46
  47 static struct fib6_rule local_rule = {
  48         .common = {
  49                 .refcnt =       ATOMIC_INIT(2),
  50                 .pref =         0,
  51                 .action =       FR_ACT_TO_TBL,
  52                 .table =        RT6_TABLE_LOCAL,
  53                 .flags =        FIB_RULE_PERMANENT,
  54         },
  55 };
  56
  57 static LIST_HEAD(fib6_rules);
  58
  59 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
  60                                    pol_lookup_t lookup)
  61 {
  62         struct fib_lookup_arg arg = {
  63                 .lookup_ptr = lookup,
  64         };
  65
  66         fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg);
  67         if (arg.rule)
  68                 fib_rule_put(arg.rule);
  69
  70         if (arg.result)
  71                 return (struct dst_entry *) arg.result;
  72
  73         dst_hold(&ip6_null_entry.u.dst);
  74         return &ip6_null_entry.u.dst;
  75 }
  76
  77 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  78                             int flags, struct fib_lookup_arg *arg)
  79 {
  80         struct rt6_info *rt = NULL;
  81         struct fib6_table *table;
  82         pol_lookup_t lookup = arg->lookup_ptr;
  83
  84         switch (rule->action) {
  85         case FR_ACT_TO_TBL:
  86                 break;
  87         case FR_ACT_UNREACHABLE:
  88                 rt = &ip6_null_entry;
  89                 goto discard_pkt;
  90         default:
  91         case FR_ACT_BLACKHOLE:
  92                 rt = &ip6_blk_hole_entry;
  93                 goto discard_pkt;
  94         case FR_ACT_PROHIBIT:
  95                 rt = &ip6_prohibit_entry;
  96                 goto discard_pkt;
  97         }
  98
  99         table = fib6_get_table(rule->table);
 100         if (table)
 101                 rt = lookup(table, flp, flags);
 102
 103         if (rt != &ip6_null_entry)
 104                 goto out;
 105         dst_release(&rt->u.dst);
 106         rt = NULL;
 107         goto out;
 108
 109 discard_pkt:
 110         dst_hold(&rt->u.dst);
 111 out:
 112         arg->result = rt;
 113         return rt == NULL ? -EAGAIN : 0;
 114 }
 115
 116
 117 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 118 {
 119         struct fib6_rule *r = (struct fib6_rule *) rule;
 120
 121         if (!ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 122                 return 0;
 123
 124         if ((flags & RT6_LOOKUP_F_HAS_SADDR) &&
 125             !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
 126                 return 0;
 127
 128         if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 129                 return 0;
 130
 131 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 132         if ((r->fwmark ^ fl->fl6_fwmark) & r->fwmask)
 133                 return 0;
 134 #endif
 135
 136         return 1;
 137 }
 138
 139 static struct nla_policy fib6_rule_policy[FRA_MAX+1] __read_mostly = {
 140         [FRA_IFNAME]    = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
 141         [FRA_PRIORITY]  = { .type = NLA_U32 },
 142         [FRA_SRC]       = { .len = sizeof(struct in6_addr) },
 143         [FRA_DST]       = { .len = sizeof(struct in6_addr) },
 144         [FRA_FWMARK]    = { .type = NLA_U32 },
 145         [FRA_FWMASK]    = { .type = NLA_U32 },
 146         [FRA_TABLE]     = { .type = NLA_U32 },
 147 };
 148
 149 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 150                                struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 151                                struct nlattr **tb)
 152 {
 153         int err = -EINVAL;
 154         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 155
 156         if (frh->src_len > 128 || frh->dst_len > 128 ||
 157             (frh->tos & ~IPV6_FLOWINFO_MASK))
 158                 goto errout;
 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(rule->table) == NULL) {
 165                         err = -ENOBUFS;
 166                         goto errout;
 167                 }
 168         }
 169
 170         if (tb[FRA_SRC])
 171                 nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
 172                            sizeof(struct in6_addr));
 173
 174         if (tb[FRA_DST])
 175                 nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 176                            sizeof(struct in6_addr));
 177
 178 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 179         if (tb[FRA_FWMARK]) {
 180                 rule6->fwmark = nla_get_u32(tb[FRA_FWMARK]);
 181                 if (rule6->fwmark) {
 182                         /*
 183                          * if the mark value is non-zero,
 184                          * all bits are compared by default
 185                          * unless a mask is explicitly specified.
 186                          */
 187                         rule6->fwmask = 0xFFFFFFFF;
 188                 }
 189         }
 190
 191         if (tb[FRA_FWMASK])
 192                 rule6->fwmask = nla_get_u32(tb[FRA_FWMASK]);
 193 #endif
 194
 195         rule6->src.plen = frh->src_len;
 196         rule6->dst.plen = frh->dst_len;
 197         rule6->tclass = frh->tos;
 198
 199         err = 0;
 200 errout:
 201         return err;
 202 }
 203
 204 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 205                              struct nlattr **tb)
 206 {
 207         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 208
 209         if (frh->src_len && (rule6->src.plen != frh->src_len))
 210                 return 0;
 211
 212         if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
 213                 return 0;
 214
 215         if (frh->tos && (rule6->tclass != frh->tos))
 216                 return 0;
 217
 218         if (tb[FRA_SRC] &&
 219             nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
 220                 return 0;
 221
 222         if (tb[FRA_DST] &&
 223             nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 224                 return 0;
 225
 226 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 227         if (tb[FRA_FWMARK] && (rule6->fwmark != nla_get_u32(tb[FRA_FWMARK])))
 228                 return 0;
 229
 230         if (tb[FRA_FWMASK] && (rule6->fwmask != nla_get_u32(tb[FRA_FWMASK])))
 231                 return 0;
 232 #endif
 233
 234         return 1;
 235 }
 236
 237 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 238                           struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 239 {
 240         struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 241
 242         frh->family = AF_INET6;
 243         frh->dst_len = rule6->dst.plen;
 244         frh->src_len = rule6->src.plen;
 245         frh->tos = rule6->tclass;
 246
 247         if (rule6->dst.plen)
 248                 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
 249                         &rule6->dst.addr);
 250
 251         if (rule6->src.plen)
 252                 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 253                         &rule6->src.addr);
 254
 255 #ifdef CONFIG_IPV6_ROUTE_FWMARK
 256         if (rule6->fwmark)
 257                 NLA_PUT_U32(skb, FRA_FWMARK, rule6->fwmark);
 258
 259         if (rule6->fwmask || rule6->fwmark)
 260                 NLA_PUT_U32(skb, FRA_FWMASK, rule6->fwmask);
 261 #endif
 262
 263         return 0;
 264
 265 nla_put_failure:
 266         return -ENOBUFS;
 267 }
 268
 269 int fib6_rules_dump(struct sk_buff *skb, struct netlink_callback *cb)
 270 {
 271         return fib_rules_dump(skb, cb, AF_INET6);
 272 }
 273
 274 static u32 fib6_rule_default_pref(void)
 275 {
 276         return 0x3FFF;
 277 }
 278
 279 static struct fib_rules_ops fib6_rules_ops = {
 280         .family                 = AF_INET6,
 281         .rule_size              = sizeof(struct fib6_rule),
 282         .action                 = fib6_rule_action,
 283         .match                  = fib6_rule_match,
 284         .configure              = fib6_rule_configure,
 285         .compare                = fib6_rule_compare,
 286         .fill                   = fib6_rule_fill,
 287         .default_pref           = fib6_rule_default_pref,
 288         .nlgroup                = RTNLGRP_IPV6_RULE,
 289         .policy                 = fib6_rule_policy,
 290         .rules_list             = &fib6_rules,
 291         .owner                  = THIS_MODULE,
 292 };
 293
 294 void __init fib6_rules_init(void)
 295 {
 296         list_add_tail(&local_rule.common.list, &fib6_rules);
 297         list_add_tail(&main_rule.common.list, &fib6_rules);
 298
 299         fib_rules_register(&fib6_rules_ops);
 300 }
 301
 302 void fib6_rules_cleanup(void)
 303 {
 304         fib_rules_unregister(&fib6_rules_ops);
 305 }