tproxy: added IPv6 support to the TPROXY target
This requires a new revision as the old target structure was IPv4 specific. Signed-off-by: Balazs Scheidler <bazsi@balabit.hu> Signed-off-by: KOVACS Krisztian <hidden@balabit.hu> Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Balazs Scheidler
Patrick McHardy
parent
3b9afb2991
commit
6ad7889327
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@ -1,5 +1,5 @@
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#ifndef _XT_TPROXY_H_target
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#define _XT_TPROXY_H_target
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#ifndef _XT_TPROXY_H
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#define _XT_TPROXY_H
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/* TPROXY target is capable of marking the packet to perform
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* redirection. We can get rid of that whenever we get support for
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@ -11,4 +11,11 @@ struct xt_tproxy_target_info {
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__be16 lport;
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};
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#endif /* _XT_TPROXY_H_target */
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struct xt_tproxy_target_info_v1 {
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u_int32_t mark_mask;
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u_int32_t mark_value;
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union nf_inet_addr laddr;
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__be16 lport;
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};
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#endif /* _XT_TPROXY_H */
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@ -1,7 +1,7 @@
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/*
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* Transparent proxy support for Linux/iptables
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*
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* Copyright (c) 2006-2007 BalaBit IT Ltd.
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* Copyright (c) 2006-2010 BalaBit IT Ltd.
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* Author: Balazs Scheidler, Krisztian Kovacs
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*
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* This program is free software; you can redistribute it and/or modify
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@ -19,15 +19,18 @@
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter/xt_TPROXY.h>
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#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
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#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
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#include <net/netfilter/nf_tproxy_core.h>
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/**
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* tproxy_handle_time_wait() - handle TCP TIME_WAIT reopen redirections
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* tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
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* @skb: The skb being processed.
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* @par: Iptables target parameters.
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* @laddr: IPv4 address to redirect to or zero.
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* @lport: TCP port to redirect to or zero.
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* @sk: The TIME_WAIT TCP socket found by the lookup.
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*
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* We have to handle SYN packets arriving to TIME_WAIT sockets
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@ -35,16 +38,16 @@
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* redirect the new connection to the proxy if there's a listener
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* socket present.
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*
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* tproxy_handle_time_wait() consumes the socket reference passed in.
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* tproxy_handle_time_wait4() consumes the socket reference passed in.
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*
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* Returns the listener socket if there's one, the TIME_WAIT socket if
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* no such listener is found, or NULL if the TCP header is incomplete.
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*/
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static struct sock *
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tproxy_handle_time_wait(struct sk_buff *skb, const struct xt_action_param *par, struct sock *sk)
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tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
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struct sock *sk)
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{
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const struct iphdr *iph = ip_hdr(skb);
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const struct xt_tproxy_target_info *tgi = par->targinfo;
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struct tcphdr _hdr, *hp;
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hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
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@ -59,13 +62,64 @@ tproxy_handle_time_wait(struct sk_buff *skb, const struct xt_action_param *par,
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struct sock *sk2;
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sk2 = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
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iph->saddr, tgi->laddr ? tgi->laddr : iph->daddr,
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hp->source, tgi->lport ? tgi->lport : hp->dest,
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par->in, NFT_LOOKUP_LISTENER);
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iph->saddr, laddr ? laddr : iph->daddr,
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hp->source, lport ? lport : hp->dest,
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skb->dev, NFT_LOOKUP_LISTENER);
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if (sk2) {
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inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
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inet_twsk_put(inet_twsk(sk));
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sk = sk2;
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}
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}
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return sk;
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}
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/**
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* tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
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* @skb: The skb being processed.
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* @tproto: Transport protocol.
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* @thoff: Transport protocol header offset.
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* @par: Iptables target parameters.
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* @sk: The TIME_WAIT TCP socket found by the lookup.
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*
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* We have to handle SYN packets arriving to TIME_WAIT sockets
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* differently: instead of reopening the connection we should rather
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* redirect the new connection to the proxy if there's a listener
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* socket present.
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*
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* tproxy_handle_time_wait6() consumes the socket reference passed in.
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*
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* Returns the listener socket if there's one, the TIME_WAIT socket if
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* no such listener is found, or NULL if the TCP header is incomplete.
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*/
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static struct sock *
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tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
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const struct xt_action_param *par,
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struct sock *sk)
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{
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const struct ipv6hdr *iph = ipv6_hdr(skb);
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struct tcphdr _hdr, *hp;
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const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
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hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
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if (hp == NULL) {
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inet_twsk_put(inet_twsk(sk));
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return NULL;
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}
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if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
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/* SYN to a TIME_WAIT socket, we'd rather redirect it
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* to a listener socket if there's one */
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struct sock *sk2;
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sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
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&iph->saddr,
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!ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
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hp->source,
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tgi->lport ? tgi->lport : hp->dest,
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skb->dev, NFT_LOOKUP_LISTENER);
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if (sk2) {
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/* yeah, there's one, let's kill the TIME_WAIT
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* socket and redirect to the listener
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*/
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inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
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inet_twsk_put(inet_twsk(sk));
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sk = sk2;
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@ -76,10 +130,10 @@ tproxy_handle_time_wait(struct sk_buff *skb, const struct xt_action_param *par,
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}
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static unsigned int
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tproxy_tg(struct sk_buff *skb, const struct xt_action_param *par)
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tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
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u_int32_t mark_mask, u_int32_t mark_value)
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{
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const struct iphdr *iph = ip_hdr(skb);
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const struct xt_tproxy_target_info *tgi = par->targinfo;
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struct udphdr _hdr, *hp;
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struct sock *sk;
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@ -87,18 +141,105 @@ tproxy_tg(struct sk_buff *skb, const struct xt_action_param *par)
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if (hp == NULL)
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return NF_DROP;
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/* check if there's an ongoing connection on the packet
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* addresses, this happens if the redirect already happened
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* and the current packet belongs to an already established
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* connection */
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sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
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iph->saddr, iph->daddr,
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hp->source, hp->dest,
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skb->dev, NFT_LOOKUP_ESTABLISHED);
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/* UDP has no TCP_TIME_WAIT state, so we never enter here */
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if (sk && sk->sk_state == TCP_TIME_WAIT)
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/* reopening a TIME_WAIT connection needs special handling */
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sk = tproxy_handle_time_wait4(skb, laddr, lport, sk);
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else if (!sk)
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/* no, there's no established connection, check if
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* there's a listener on the redirected addr/port */
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sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
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iph->saddr, laddr ? laddr : iph->daddr,
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hp->source, lport ? lport : hp->dest,
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skb->dev, NFT_LOOKUP_LISTENER);
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/* NOTE: assign_sock consumes our sk reference */
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if (sk && nf_tproxy_assign_sock(skb, sk)) {
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/* This should be in a separate target, but we don't do multiple
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targets on the same rule yet */
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skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
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pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
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iph->protocol, &iph->daddr, ntohs(hp->dest),
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&laddr, ntohs(lport), skb->mark);
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return NF_ACCEPT;
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}
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pr_debug("no socket, dropping: proto %hhu %08x:%hu -> %08x:%hu, mark: %x\n",
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iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
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ntohl(laddr), ntohs(lport), skb->mark);
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return NF_DROP;
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}
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static unsigned int
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tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_tproxy_target_info *tgi = par->targinfo;
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return tproxy_tg4(skb, tgi->laddr, tgi->lport, tgi->mark_mask, tgi->mark_value);
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}
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static unsigned int
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tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
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return tproxy_tg4(skb, tgi->laddr.ip, tgi->lport, tgi->mark_mask, tgi->mark_value);
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}
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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static unsigned int
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tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct ipv6hdr *iph = ipv6_hdr(skb);
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const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
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struct udphdr _hdr, *hp;
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struct sock *sk;
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int thoff;
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int tproto;
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tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
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if (tproto < 0) {
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pr_debug("unable to find transport header in IPv6 packet, dropping\n");
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return NF_DROP;
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}
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hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
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if (hp == NULL) {
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pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
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return NF_DROP;
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}
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/* check if there's an ongoing connection on the packet
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* addresses, this happens if the redirect already happened
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* and the current packet belongs to an already established
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* connection */
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sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
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&iph->saddr, &iph->daddr,
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hp->source, hp->dest,
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par->in, NFT_LOOKUP_ESTABLISHED);
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/* UDP has no TCP_TIME_WAIT state, so we never enter here */
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if (sk && sk->sk_state == TCP_TIME_WAIT)
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sk = tproxy_handle_time_wait(skb, par, sk);
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/* reopening a TIME_WAIT connection needs special handling */
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sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
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else if (!sk)
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sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
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iph->saddr, tgi->laddr ? tgi->laddr : iph->daddr,
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hp->source, tgi->lport ? tgi->lport : hp->dest,
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/* no there's no established connection, check if
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* there's a listener on the redirected addr/port */
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sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
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&iph->saddr,
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!ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
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hp->source,
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tgi->lport ? tgi->lport : hp->dest,
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par->in, NFT_LOOKUP_LISTENER);
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/* NOTE: assign_sock consumes our sk reference */
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@ -107,19 +248,33 @@ tproxy_tg(struct sk_buff *skb, const struct xt_action_param *par)
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targets on the same rule yet */
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skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
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pr_debug("redirecting: proto %u %08x:%u -> %08x:%u, mark: %x\n",
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iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
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ntohl(tgi->laddr), ntohs(tgi->lport), skb->mark);
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pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
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tproto, &iph->saddr, ntohs(hp->dest),
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&tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
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return NF_ACCEPT;
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}
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pr_debug("no socket, dropping: proto %u %08x:%u -> %08x:%u, mark: %x\n",
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iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
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ntohl(tgi->laddr), ntohs(tgi->lport), skb->mark);
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pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
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tproto, &iph->saddr, ntohs(hp->dest),
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&tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
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return NF_DROP;
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}
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static int tproxy_tg_check(const struct xt_tgchk_param *par)
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static int tproxy_tg6_check(const struct xt_tgchk_param *par)
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{
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const struct ip6t_ip6 *i = par->entryinfo;
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if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
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&& !(i->flags & IP6T_INV_PROTO))
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return 0;
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pr_info("Can be used only in combination with "
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"either -p tcp or -p udp\n");
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return -EINVAL;
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}
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#endif
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static int tproxy_tg4_check(const struct xt_tgchk_param *par)
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{
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const struct ipt_ip *i = par->entryinfo;
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@ -132,31 +287,64 @@ static int tproxy_tg_check(const struct xt_tgchk_param *par)
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return -EINVAL;
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}
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static struct xt_target tproxy_tg_reg __read_mostly = {
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.name = "TPROXY",
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.family = NFPROTO_IPV4,
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.table = "mangle",
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.target = tproxy_tg,
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.targetsize = sizeof(struct xt_tproxy_target_info),
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.checkentry = tproxy_tg_check,
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.hooks = 1 << NF_INET_PRE_ROUTING,
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.me = THIS_MODULE,
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static struct xt_target tproxy_tg_reg[] __read_mostly = {
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{
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.name = "TPROXY",
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.family = NFPROTO_IPV4,
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.table = "mangle",
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.target = tproxy_tg4_v0,
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.revision = 0,
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.targetsize = sizeof(struct xt_tproxy_target_info),
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.checkentry = tproxy_tg4_check,
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.hooks = 1 << NF_INET_PRE_ROUTING,
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.me = THIS_MODULE,
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},
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{
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.name = "TPROXY",
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.family = NFPROTO_IPV4,
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.table = "mangle",
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.target = tproxy_tg4_v1,
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.revision = 1,
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.targetsize = sizeof(struct xt_tproxy_target_info_v1),
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.checkentry = tproxy_tg4_check,
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.hooks = 1 << NF_INET_PRE_ROUTING,
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.me = THIS_MODULE,
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},
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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{
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.name = "TPROXY",
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.family = NFPROTO_IPV6,
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.table = "mangle",
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.target = tproxy_tg6_v1,
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.revision = 1,
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.targetsize = sizeof(struct xt_tproxy_target_info_v1),
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.checkentry = tproxy_tg6_check,
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.hooks = 1 << NF_INET_PRE_ROUTING,
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.me = THIS_MODULE,
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},
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#endif
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};
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static int __init tproxy_tg_init(void)
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{
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nf_defrag_ipv4_enable();
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return xt_register_target(&tproxy_tg_reg);
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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nf_defrag_ipv6_enable();
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#endif
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return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
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}
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static void __exit tproxy_tg_exit(void)
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{
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xt_unregister_target(&tproxy_tg_reg);
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xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
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}
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module_init(tproxy_tg_init);
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module_exit(tproxy_tg_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Krisztian Kovacs");
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MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
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MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
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MODULE_ALIAS("ipt_TPROXY");
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MODULE_ALIAS("ip6t_TPROXY");
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