LXR linux/net/ipv4/netfilter/nft_chain_route

   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
  10#include <linux/module.h>
  11#include <linux/init.h>
  12#include <linux/list.h>
  13#include <linux/skbuff.h>
  14#include <linux/netlink.h>
  15#include <linux/netfilter.h>
  16#include <linux/netfilter_ipv4.h>
  17#include <linux/netfilter/nfnetlink.h>
  18#include <linux/netfilter/nf_tables.h>
  19#include <net/netfilter/nf_tables.h>
  20#include <net/netfilter/nf_tables_ipv4.h>
  21#include <net/route.h>
  22#include <net/ip.h>
  23
  24static unsigned int nf_route_table_hook(void *priv,
  25                                        struct sk_buff *skb,
  26                                        const struct nf_hook_state *state)
  27{
  28        unsigned int ret;
  29        struct nft_pktinfo pkt;
  30        u32 mark;
  31        __be32 saddr, daddr;
  32        u_int8_t tos;
  33        const struct iphdr *iph;
  34        int err;
  35
  36        nft_set_pktinfo(&pkt, skb, state);
  37        nft_set_pktinfo_ipv4(&pkt, skb);
  38
  39        mark = skb->mark;
  40        iph = ip_hdr(skb);
  41        saddr = iph->saddr;
  42        daddr = iph->daddr;
  43        tos = iph->tos;
  44
  45        ret = nft_do_chain(&pkt, priv);
  46        if (ret != NF_DROP && ret != NF_STOLEN) {
  47                iph = ip_hdr(skb);
  48
  49                if (iph->saddr != saddr ||
  50                    iph->daddr != daddr ||
  51                    skb->mark != mark ||
  52                    iph->tos != tos) {
  53                        err = ip_route_me_harder(state->net, skb, RTN_UNSPEC);
  54                        if (err < 0)
  55                                ret = NF_DROP_ERR(err);
  56                }
  57        }
  58        return ret;
  59}
  60
  61static const struct nft_chain_type nft_chain_route_ipv4 = {
  62        .name           = "route",
  63        .type           = NFT_CHAIN_T_ROUTE,
  64        .family         = NFPROTO_IPV4,
  65        .owner          = THIS_MODULE,
  66        .hook_mask      = (1 << NF_INET_LOCAL_OUT),
  67        .hooks          = {
  68                [NF_INET_LOCAL_OUT]     = nf_route_table_hook,
  69        },
  70};
  71
  72static int __init nft_chain_route_init(void)
  73{
  74        nft_register_chain_type(&nft_chain_route_ipv4);
  75
  76        return 0;
  77}
  78
  79static void __exit nft_chain_route_exit(void)
  80{
  81        nft_unregister_chain_type(&nft_chain_route_ipv4);
  82}
  83
  84module_init(nft_chain_route_init);
  85module_exit(nft_chain_route_exit);
  86
  87MODULE_LICENSE("GPL");
  88MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  89MODULE_ALIAS_NFT_CHAIN(AF_INET, "route");
  90