2 * Copyright (C) 2007-2008 BalaBit IT Ltd.
3 * Author: Krisztian Kovacs
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.
11 #include <net/netfilter/nf_tproxy.h>
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
15 #include <net/inet_sock.h>
17 #include <net/checksum.h>
20 #include <linux/inetdevice.h>
23 nf_tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb,
24 __be32 laddr, __be16 lport, struct sock *sk)
26 const struct iphdr *iph = ip_hdr(skb);
27 struct tcphdr _hdr, *hp;
29 hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
31 inet_twsk_put(inet_twsk(sk));
35 if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
36 /* SYN to a TIME_WAIT socket, we'd rather redirect it
37 * to a listener socket if there's one */
40 sk2 = nf_tproxy_get_sock_v4(net, skb, iph->protocol,
41 iph->saddr, laddr ? laddr : iph->daddr,
42 hp->source, lport ? lport : hp->dest,
43 skb->dev, NF_TPROXY_LOOKUP_LISTENER);
45 inet_twsk_deschedule_put(inet_twsk(sk));
52 EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait4);
54 __be32 nf_tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
56 struct in_device *indev;
63 indev = __in_dev_get_rcu(skb->dev);
64 for_primary_ifa(indev) {
65 laddr = ifa->ifa_local;
69 return laddr ? laddr : daddr;
71 EXPORT_SYMBOL_GPL(nf_tproxy_laddr4);
74 nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb,
76 const __be32 saddr, const __be32 daddr,
77 const __be16 sport, const __be16 dport,
78 const struct net_device *in,
79 const enum nf_tproxy_lookup_t lookup_type)
85 struct tcphdr _hdr, *hp;
87 hp = skb_header_pointer(skb, ip_hdrlen(skb),
88 sizeof(struct tcphdr), &_hdr);
92 switch (lookup_type) {
93 case NF_TPROXY_LOOKUP_LISTENER:
94 sk = inet_lookup_listener(net, &tcp_hashinfo, skb,
101 if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
103 /* NOTE: we return listeners even if bound to
104 * 0.0.0.0, those are filtered out in
105 * xt_socket, since xt_TPROXY needs 0 bound
109 case NF_TPROXY_LOOKUP_ESTABLISHED:
110 sk = inet_lookup_established(net, &tcp_hashinfo,
111 saddr, sport, daddr, dport,
120 sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
123 int connected = (sk->sk_state == TCP_ESTABLISHED);
124 int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
126 /* NOTE: we return listeners even if bound to
127 * 0.0.0.0, those are filtered out in
128 * xt_socket, since xt_TPROXY needs 0 bound
131 if ((lookup_type == NF_TPROXY_LOOKUP_ESTABLISHED &&
132 (!connected || wildcard)) ||
133 (lookup_type == NF_TPROXY_LOOKUP_LISTENER && connected)) {
144 pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
145 protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
149 EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v4);
151 MODULE_LICENSE("GPL");
152 MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
153 MODULE_DESCRIPTION("Netfilter IPv4 transparent proxy support");