net/ipv6/netfilter/nft_chain_route_ipv6.c

   1 /*
   2  * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
   3  * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Development of this code funded by Astaro AG (http://www.astaro.com/)
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/list.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/netlink.h>
  17 #include <linux/netfilter.h>
  18 #include <linux/netfilter_ipv6.h>
  19 #include <linux/netfilter/nfnetlink.h>
  20 #include <linux/netfilter/nf_tables.h>
  21 #include <net/netfilter/nf_tables.h>
  22 #include <net/route.h>
  23
  24 static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
  25                                         struct sk_buff *skb,
  26                                         const struct net_device *in,
  27                                         const struct net_device *out,
  28                                         int (*okfn)(struct sk_buff *))
  29 {
  30         unsigned int ret;
  31         struct in6_addr saddr, daddr;
  32         u_int8_t hop_limit;
  33         u32 mark, flowlabel;
  34
  35         /* save source/dest address, mark, hoplimit, flowlabel, priority */
  36         memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
  37         memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
  38         mark = skb->mark;
  39         hop_limit = ipv6_hdr(skb)->hop_limit;
  40
  41         /* flowlabel and prio (includes version, which shouldn't change either */
  42         flowlabel = *((u32 *)ipv6_hdr(skb));
  43
  44         ret = nft_do_chain(ops, skb, in, out, okfn);
  45         if (ret != NF_DROP && ret != NF_QUEUE &&
  46             (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) ||
  47              memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) ||
  48              skb->mark != mark ||
  49              ipv6_hdr(skb)->hop_limit != hop_limit ||
  50              flowlabel != *((u_int32_t *)ipv6_hdr(skb))))
  51                 return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
  52
  53         return ret;
  54 }
  55
  56 static struct nf_chain_type nft_chain_route_ipv6 = {
  57         .family         = NFPROTO_IPV6,
  58         .name           = "route",
  59         .type           = NFT_CHAIN_T_ROUTE,
  60         .hook_mask      = (1 << NF_INET_LOCAL_OUT),
  61         .fn             = {
  62                 [NF_INET_LOCAL_OUT]     = nf_route_table_hook,
  63         },
  64         .me             = THIS_MODULE,
  65 };
  66
  67 static int __init nft_chain_route_init(void)
  68 {
  69         return nft_register_chain_type(&nft_chain_route_ipv6);
  70 }
  71
  72 static void __exit nft_chain_route_exit(void)
  73 {
  74         nft_unregister_chain_type(&nft_chain_route_ipv6);
  75 }
  76
  77 module_init(nft_chain_route_init);
  78 module_exit(nft_chain_route_exit);
  79
  80 MODULE_LICENSE("GPL");
  81 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  82 MODULE_ALIAS_NFT_CHAIN(AF_INET6, "route");