On Nov 7, 2009, at 10:38 AM, Gerald Combs wrote:
In capture_interface_list we don't set the interface description if we
get an empty string from dumpcap:
if (strlen(if_parts[1]) > 0)
if_info->description = g_strdup(if_parts[1]);
Hmm.
Looking at capture_opts_list_interfaces(), which is what dumpcap uses
to list the interfaces, if it's generating (more easily) machine-
readable output, the output generated for a missing description
(if_info->description is null) and the output generated for an empty
description (if_info->description points to a null string) are the same.
This is apparently how we ended up with null description pointers in
capture_get_if_icon. Should we take out the if statement and set the
description no matter what?
An empty description is no more useful than a null description, and,
as indicated, pcap_findalldevs() doesn't guarantee that it will return
a description for every adapter, so I wouldn't be inclined to do that;
I'd be inclined to leave the if statement there.
(I'm thinking of redoing the way that dumpcap communicates with its
callers for various reasons, including adding support for all the new
stuff I added in libpcap 1.0, so, for example, we can have a "monitor
mode" checkbox for wireless adapters if the relevant APIs work; I'll
see if I can distinguish between "no description" and "empty
description".)
I'm also curious how the description managed to be null - at least
according to the bug report, Marvell *does* supply a description:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Marvell Yukon 88E8056 PCI-E
Gigabit Ethernet Controller
Physical Address. . . . . . . . . : 00-22-15-##-##-##
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::####::####.....
IPv4 Address. . . . . . . . . . . : a.b.c.h(Preferred)
Subnet Mask . . . . . . . . . . . : w.x.y.z
Lease Obtained. . . . . . . . . . : 06 November 2009 18:38:00
Lease Expires . . . . . . . . . . : 09 November 2009 18:37:59
Default Gateway . . . . . . . . . : a.b.c.d
DHCP Server . . . . . . . . . . . : a.b.c.d
DNS Servers . . . . . . . . . . . : a.b.c.d
NetBIOS over Tcpip. . . . . . . . : Enabled
so there's presumably something odd going on in WinPcap here.
