2005-09-15 01:07:23

by Chris Wright

[permalink] [raw]
Subject: [PATCH 07/11] [NETFILTER]: Fix DHCP + MASQUERADE problem

-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 <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
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);

--