Get a link-local IP when wired and DHCP fails

[Bastien Nocera <hadess hadess net>]

Heya,

Here's a (small) patch I wrote after a discussion with Dan.

The use-cases are:
- Plug my laptop and desktop together, via a crossed-cable or some cheap
hub, they both get a nice little IP address, and they can talk.
- Create an ad-hoc non-encrypted network on my desktop, join in on my
laptop, can't get a DHCP address (not running that kind of server on my
desktop, too lazy), gets a nice little IP address, and they can talk.

The only case left is when we have an ad-hoc encrypted network, as it's
not really possible to know whether the DHCP request failure is due to
no-DHCP server, or wrong WEP key.
I remember Apple's solution to a similar problem (detecting whether a
WEP key is accepted) being pretty ugly and Airport AP specific, but I
don't quite remember the details.

Any comments?

---
Bastien Nocera <hadess hadess net> 

Index: NetworkManagerDevice.c
===================================================================
RCS file: /cvs/gnome/NetworkManager/src/NetworkManagerDevice.c,v
retrieving revision 1.145
diff -u -p -r1.145 NetworkManagerDevice.c
--- NetworkManagerDevice.c	30 Jun 2005 14:28:52 -0000	1.145
+++ NetworkManagerDevice.c	30 Jun 2005 18:55:42 -0000
@@ -2751,9 +2751,20 @@ static gboolean nm_device_activate_stage
 
 	if (ap && nm_ap_get_user_created (ap))
 		ip4_config = nm_device_new_ip4_autoip_config (dev);
-	else if (nm_device_get_use_dhcp (dev))
+	else if (nm_device_get_use_dhcp (dev)) {
 		ip4_config = nm_dhcp_manager_get_ip4_config (data->dhcp_manager, req);
-	else
+
+		/* Couldn't get a DHCP address, so we'll try link-local
+		 * for wired, and wireless non-encrypted networks, as if
+		 * we have encryption on wireless, it could be a wrong
+		 * WEP key causing the failure
+		 */
+		if (ip4_config == NULL && nm_device_is_wired (dev)) {
+			ip4_config = nm_device_new_ip4_autoip_config (dev);
+		} else if (ip4_config == NULL && nm_device_is_wireless (dev) == FALSE && nm_ap_get_encrypted (ap) == FALSE) {
+			ip4_config = nm_device_new_ip4_autoip_config (dev);
+		}
+	} else
 		ip4_config = nm_system_device_new_ip4_system_config (dev);
 
 	if (nm_device_activation_should_cancel (dev))