From 9ad2d745a23853927a19789b034d9eb2e62d78ee Mon Sep 17 00:00:00 2001 From: KOVACS Krisztian Date: Wed, 8 Oct 2008 11:35:12 +0200 Subject: [PATCH] netfilter: iptables tproxy core The iptables tproxy core is a module that contains the common routines used by various tproxy related modules (TPROXY target and socket match) Signed-off-by: KOVACS Krisztian Signed-off-by: Patrick McHardy --- include/net/netfilter/nf_tproxy_core.h | 32 +++++++++ net/netfilter/Kconfig | 15 ++++ net/netfilter/Makefile | 3 + net/netfilter/nf_tproxy_core.c | 96 ++++++++++++++++++++++++++ 4 files changed, 146 insertions(+) create mode 100644 include/net/netfilter/nf_tproxy_core.h create mode 100644 net/netfilter/nf_tproxy_core.c diff --git a/include/net/netfilter/nf_tproxy_core.h b/include/net/netfilter/nf_tproxy_core.h new file mode 100644 index 000000000000..208b46f4d6d2 --- /dev/null +++ b/include/net/netfilter/nf_tproxy_core.h @@ -0,0 +1,32 @@ +#ifndef _NF_TPROXY_CORE_H +#define _NF_TPROXY_CORE_H + +#include +#include +#include +#include +#include +#include + +/* look up and get a reference to a matching socket */ +extern struct sock * +nf_tproxy_get_sock_v4(struct net *net, const u8 protocol, + const __be32 saddr, const __be32 daddr, + const __be16 sport, const __be16 dport, + const struct net_device *in, bool listening); + +static inline void +nf_tproxy_put_sock(struct sock *sk) +{ + /* TIME_WAIT inet sockets have to be handled differently */ + if ((sk->sk_protocol == IPPROTO_TCP) && (sk->sk_state == TCP_TIME_WAIT)) + inet_twsk_put(inet_twsk(sk)); + else + sock_put(sk); +} + +/* assign a socket to the skb -- consumes sk */ +int +nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk); + +#endif diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 4a464857f216..ed1dcfb61e12 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -287,6 +287,21 @@ config NF_CT_NETLINK help This option enables support for a netlink-based userspace interface +# transparent proxy support +config NETFILTER_TPROXY + tristate "Transparent proxying support (EXPERIMENTAL)" + depends on EXPERIMENTAL + depends on IP_NF_MANGLE + depends on NETFILTER_ADVANCED + help + This option enables transparent proxying support, that is, + support for handling non-locally bound IPv4 TCP and UDP sockets. + For it to work you will have to configure certain iptables rules + and use policy routing. For more information on how to set it up + see Documentation/networking/tproxy.txt. + + To compile it as a module, choose M here. If unsure, say N. + config NETFILTER_XTABLES tristate "Netfilter Xtables support (required for ip_tables)" default m if NETFILTER_ADVANCED=n diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index f101cf61e6f8..fc8bbb48d383 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -34,6 +34,9 @@ obj-$(CONFIG_NF_CONNTRACK_SANE) += nf_conntrack_sane.o obj-$(CONFIG_NF_CONNTRACK_SIP) += nf_conntrack_sip.o obj-$(CONFIG_NF_CONNTRACK_TFTP) += nf_conntrack_tftp.o +# transparent proxy support +obj-$(CONFIG_NETFILTER_TPROXY) += nf_tproxy_core.o + # generic X tables obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o diff --git a/net/netfilter/nf_tproxy_core.c b/net/netfilter/nf_tproxy_core.c new file mode 100644 index 000000000000..fe34f4bf74cc --- /dev/null +++ b/net/netfilter/nf_tproxy_core.c @@ -0,0 +1,96 @@ +/* + * Transparent proxy support for Linux/iptables + * + * Copyright (c) 2006-2007 BalaBit IT Ltd. + * Author: Balazs Scheidler, Krisztian Kovacs + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include +#include + +#include +#include +#include +#include +#include + +struct sock * +nf_tproxy_get_sock_v4(struct net *net, const u8 protocol, + const __be32 saddr, const __be32 daddr, + const __be16 sport, const __be16 dport, + const struct net_device *in, bool listening_only) +{ + struct sock *sk; + + /* look up socket */ + switch (protocol) { + case IPPROTO_TCP: + if (listening_only) + sk = __inet_lookup_listener(net, &tcp_hashinfo, + daddr, ntohs(dport), + in->ifindex); + else + sk = __inet_lookup(net, &tcp_hashinfo, + saddr, sport, daddr, dport, + in->ifindex); + break; + case IPPROTO_UDP: + sk = udp4_lib_lookup(net, saddr, sport, daddr, dport, + in->ifindex); + break; + default: + WARN_ON(1); + sk = NULL; + } + + pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, listener only: %d, sock %p\n", + protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), listening_only, sk); + + return sk; +} +EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v4); + +static void +nf_tproxy_destructor(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + + skb->sk = NULL; + skb->destructor = NULL; + + if (sk) + nf_tproxy_put_sock(sk); +} + +/* consumes sk */ +int +nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk) +{ + if (inet_sk(sk)->transparent) { + skb->sk = sk; + skb->destructor = nf_tproxy_destructor; + return 1; + } else + nf_tproxy_put_sock(sk); + + return 0; +} +EXPORT_SYMBOL_GPL(nf_tproxy_assign_sock); + +static int __init nf_tproxy_init(void) +{ + pr_info("NF_TPROXY: Transparent proxy support initialized, version 4.1.0\n"); + pr_info("NF_TPROXY: Copyright (c) 2006-2007 BalaBit IT Ltd.\n"); + return 0; +} + +module_init(nf_tproxy_init); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Krisztian Kovacs"); +MODULE_DESCRIPTION("Transparent proxy support core routines"); -- 2.20.1