net/ipv6/netfilter/nf_table_route_ipv6.c

   1 /*
   2  * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/list.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netlink.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/netfilter_ipv6.h>
  18 #include <linux/netfilter/nfnetlink.h>
  19 #include <linux/netfilter/nf_tables.h>
  20 #include <net/netfilter/nf_tables.h>
  21 #include <net/route.h>
  22
  23 static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
  24                                         struct sk_buff *skb,
  25                                         const struct net_device *in,
  26                                         const struct net_device *out,
  27                                         int (*okfn)(struct sk_buff *))
  28 {
  29         unsigned int ret;
  30         struct in6_addr saddr, daddr;
  31         u_int8_t hop_limit;
  32         u32 mark, flowlabel;
  33
  34         /* save source/dest address, mark, hoplimit, flowlabel, priority */
  35         memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
  36         memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
  37         mark = skb->mark;
  38         hop_limit = ipv6_hdr(skb)->hop_limit;
  39
  40         /* flowlabel and prio (includes version, which shouldn't change either */
  41         flowlabel = *((u32 *)ipv6_hdr(skb));
  42
  43         ret = nft_do_chain(ops, skb, in, out, okfn);
  44         if (ret != NF_DROP && ret != NF_QUEUE &&
  45             (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) ||
  46              memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) ||
  47              skb->mark != mark ||
  48              ipv6_hdr(skb)->hop_limit != hop_limit ||
  49              flowlabel != *((u_int32_t *)ipv6_hdr(skb))))
  50                 return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
  51
  52         return ret;
  53 }
  54
  55 static struct nft_base_chain nf_chain_route_output __read_mostly = {
  56         .chain  = {
  57                 .name           = "OUTPUT",
  58                 .rules          = LIST_HEAD_INIT(nf_chain_route_output.chain.rules),
  59                 .flags          = NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
  60         },
  61         .ops    = {
  62                 .hook           = nf_route_table_hook,
  63                 .owner          = THIS_MODULE,
  64                 .pf             = NFPROTO_IPV6,
  65                 .hooknum        = NF_INET_LOCAL_OUT,
  66                 .priority       = NF_IP6_PRI_MANGLE,
  67                 .priv           = &nf_chain_route_output.chain,
  68         },
  69 };
  70
  71 static struct nft_table nf_table_route_ipv6 __read_mostly = {
  72         .name   = "route",
  73         .chains = LIST_HEAD_INIT(nf_table_route_ipv6.chains),
  74 };
  75
  76 static int __init nf_table_route_init(void)
  77 {
  78         list_add_tail(&nf_chain_route_output.chain.list,
  79                       &nf_table_route_ipv6.chains);
  80         return nft_register_table(&nf_table_route_ipv6, NFPROTO_IPV6);
  81 }
  82
  83 static void __exit nf_table_route_exit(void)
  84 {
  85         nft_unregister_table(&nf_table_route_ipv6, NFPROTO_IPV6);
  86 }
  87
  88 module_init(nf_table_route_init);
  89 module_exit(nf_table_route_exit);
  90
  91 MODULE_LICENSE("GPL");
  92 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  93 MODULE_ALIAS_NFT_TABLE(AF_INET6, "route");