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/netfilter/nf_tables_ipv6.h>
  23 #include <net/route.h>
  24
  25 static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
  26                                         struct sk_buff *skb,
  27                                         const struct net_device *in,
  28                                         const struct net_device *out,
  29                                         int (*okfn)(struct sk_buff *))
  30 {
  31         unsigned int ret;
  32         struct nft_pktinfo pkt;
  33         struct in6_addr saddr, daddr;
  34         u_int8_t hop_limit;
  35         u32 mark, flowlabel;
  36
  37         /* malformed packet, drop it */
  38         if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
  39                 return NF_DROP;
  40
  41         /* save source/dest address, mark, hoplimit, flowlabel, priority */
  42         memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
  43         memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
  44         mark = skb->mark;
  45         hop_limit = ipv6_hdr(skb)->hop_limit;
  46
  47         /* flowlabel and prio (includes version, which shouldn't change either */
  48         flowlabel = *((u32 *)ipv6_hdr(skb));
  49
  50         ret = nft_do_chain_pktinfo(&pkt, ops);
  51         if (ret != NF_DROP && ret != NF_QUEUE &&
  52             (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) ||
  53              memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) ||
  54              skb->mark != mark ||
  55              ipv6_hdr(skb)->hop_limit != hop_limit ||
  56              flowlabel != *((u_int32_t *)ipv6_hdr(skb))))
  57                 return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
  58
  59         return ret;
  60 }
  61
  62 static struct nf_chain_type nft_chain_route_ipv6 = {
  63         .family         = NFPROTO_IPV6,
  64         .name           = "route",
  65         .type           = NFT_CHAIN_T_ROUTE,
  66         .hook_mask      = (1 << NF_INET_LOCAL_OUT),
  67         .fn             = {
  68                 [NF_INET_LOCAL_OUT]     = nf_route_table_hook,
  69         },
  70         .me             = THIS_MODULE,
  71 };
  72
  73 static int __init nft_chain_route_init(void)
  74 {
  75         return nft_register_chain_type(&nft_chain_route_ipv6);
  76 }
  77
  78 static void __exit nft_chain_route_exit(void)
  79 {
  80         nft_unregister_chain_type(&nft_chain_route_ipv6);
  81 }
  82
  83 module_init(nft_chain_route_init);
  84 module_exit(nft_chain_route_exit);
  85
  86 MODULE_LICENSE("GPL");
  87 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  88 MODULE_ALIAS_NFT_CHAIN(AF_INET6, "route");