From: Roy Marples <roy@marples.name>
Date: Thu, 11 Oct 2007 08:56:46 +0000 (+0000)
Subject: If we're on a different subnet from the one we get DHCP for, don't use our current... 
X-Git-Tag: v3.2.3~196
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8b67eaba15ceefc46412b6ea2bf50a0dbc384d3a;p=thirdparty%2Fdhcpcd.git

If we're on a different subnet from the one we get DHCP for, don't use our current address in messages. Thanks to Wilson Callan.
---

diff --git a/ChangeLog b/ChangeLog
index 3c76ccc9..2857757c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,5 @@
+If we're on a different subnet from the one we get DHCP for, don't
+use our current address in messages. Thanks to Wilson Callan.
 Skip over bogus EINTR error on select when arp checking for a
 different address from what we already have. This should not
 happen, so a better fix is probably needed.
diff --git a/dhcp.c b/dhcp.c
index c180ed6b..2328c836 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -93,6 +93,11 @@ size_t send_message (const interface_t *iface, const dhcp_t *dhcp,
 		/* Just incase we haven't actually configured the address yet */
 		if (type == DHCP_INFORM && iface->previous_address.s_addr == 0)
 			message.ciaddr = dhcp->address.s_addr;
+
+		/* Zero the address if we're currently on a different subnet */
+		if (type == DHCP_REQUEST &&
+			iface->previous_netmask.s_addr != dhcp->netmask.s_addr)
+			message->ciaddr = from.s_addr = 0;
 	}
 
 	message.op = DHCP_BOOTREQUEST;