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