From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wright Subject: [PATCH 07/11] [NETFILTER]: Fix DHCP + MASQUERADE problem Date: Wed, 14 Sep 2005 18:03:50 -0700 Message-ID: <20050915010407.117847000@localhost.localdomain> References: <20050915010343.577985000@localhost.localdomain> Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Chuck Wolber , torvalds@osdl.org, akpm@osdl.org, alan@lxorguk.ukuu.org.uk, Patrick McHardy , Netfilter Development Mailinglist , Chris Wright Return-path: To: linux-kernel@vger.kernel.org, stable@kernel.org, "David S. Miller" Content-Disposition: inline; filename=netfilter-fix-dhcp-masquerade-problem.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org -stable review patch. If anyone has any objections, please let us know. ------------------ In 2.6.13-rcX the MASQUERADE target was changed not to exclude local packets for better source address consistency. This breaks DHCP clients using UDP sockets when the DHCP requests are caught by a MASQUERADE rule because the MASQUERADE target drops packets when no address is configured on the outgoing interface. This patch makes it ignore packets with a source address of 0. Thanks to Rusty for this suggestion. Signed-off-by: Patrick McHardy Signed-off-by: Chris Wright --- net/ipv4/netfilter/ipt_MASQUERADE.c | 6 ++++++ 1 files changed, 6 insertions(+) Index: linux-2.6.13.y/net/ipv4/netfilter/ipt_MASQUERADE.c =================================================================== --- linux-2.6.13.y.orig/net/ipv4/netfilter/ipt_MASQUERADE.c +++ linux-2.6.13.y/net/ipv4/netfilter/ipt_MASQUERADE.c @@ -95,6 +95,12 @@ masquerade_target(struct sk_buff **pskb, IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)); + /* Source address is 0.0.0.0 - locally generated packet that is + * probably not supposed to be masqueraded. + */ + if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip == 0) + return NF_ACCEPT; + mr = targinfo; rt = (struct rtable *)(*pskb)->dst; newsrc = inet_select_addr(out, rt->rt_gateway, RT_SCOPE_UNIVERSE); --