net/netfilter/nf_tproxy_core.c

   1 /*
   2  * Transparent proxy support for Linux/iptables
   3  *
   4  * Copyright (c) 2006-2007 BalaBit IT Ltd.
   5  * Author: Balazs Scheidler, Krisztian Kovacs
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14
  15 #include <linux/net.h>
  16 #include <linux/if.h>
  17 #include <linux/netdevice.h>
  18 #include <net/udp.h>
  19 #include <net/netfilter/nf_tproxy_core.h>
  20
  21 struct sock *
  22 nf_tproxy_get_sock_v4(struct net *net, const u8 protocol,
  23                       const __be32 saddr, const __be32 daddr,
  24                       const __be16 sport, const __be16 dport,
  25                       const struct net_device *in, bool listening_only)
  26 {
  27         struct sock *sk;
  28
  29         /* look up socket */
  30         switch (protocol) {
  31         case IPPROTO_TCP:
  32                 if (listening_only)
  33                         sk = __inet_lookup_listener(net, &tcp_hashinfo,
  34                                                     daddr, ntohs(dport),
  35                                                     in->ifindex);
  36                 else
  37                         sk = __inet_lookup(net, &tcp_hashinfo,
  38                                            saddr, sport, daddr, dport,
  39                                            in->ifindex);
  40                 break;
  41         case IPPROTO_UDP:
  42                 sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
  43                                      in->ifindex);
  44                 break;
  45         default:
  46                 WARN_ON(1);
  47                 sk = NULL;
  48         }
  49
  50         pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, listener only: %d, sock %p\n",
  51                  protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), listening_only, sk);
  52
  53         return sk;
  54 }
  55 EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v4);
  56
  57 static void
  58 nf_tproxy_destructor(struct sk_buff *skb)
  59 {
  60         struct sock *sk = skb->sk;
  61
  62         skb->sk = NULL;
  63         skb->destructor = NULL;
  64
  65         if (sk)
  66                 nf_tproxy_put_sock(sk);
  67 }
  68
  69 /* consumes sk */
  70 int
  71 nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk)
  72 {
  73         if (inet_sk(sk)->transparent) {
  74                 skb_orphan(skb);
  75                 skb->sk = sk;
  76                 skb->destructor = nf_tproxy_destructor;
  77                 return 1;
  78         } else
  79                 nf_tproxy_put_sock(sk);
  80
  81         return 0;
  82 }
  83 EXPORT_SYMBOL_GPL(nf_tproxy_assign_sock);
  84
  85 static int __init nf_tproxy_init(void)
  86 {
  87         pr_info("NF_TPROXY: Transparent proxy support initialized, version 4.1.0\n");
  88         pr_info("NF_TPROXY: Copyright (c) 2006-2007 BalaBit IT Ltd.\n");
  89         return 0;
  90 }
  91
  92 module_init(nf_tproxy_init);
  93
  94 MODULE_LICENSE("GPL");
  95 MODULE_AUTHOR("Krisztian Kovacs");
  96 MODULE_DESCRIPTION("Transparent proxy support core routines");