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How can you determine if a network adapter is wired or wireless with WinPCap?

I'm writing a program that uses winpcap to capture some specific network traffic that is sent out by our switches.

However, wireless devices will never receive those packet so I'm trying to figure out how to determine if a network adapter is wireless or wired (so that I can then skip capturing on the wireless adapters altogether).

My first thought is to check the medium of the interface chosen (currently chosen based on the IP address of that adapter - the logic is that if it has an IP address, it is connected). The problem is, is that pcap_datalink() will return DLT_EN10MB, whether its wired or wireless.

The next thought was to try pcap_can_set_rfmon(), which should tell me if the device cannot be set to monitoring mode (and therefore if it is or isn't wired). However, I seem to get a 2019 linking error when I try to use this, which seems to be supposedly to do with the function not being supported on Windows without Airpcap?

I don't really see what else to try but it would be great if someone had any pointers. I'm wondering how difficult and convoluted it would end up becoming if I had to start using NDIS to determine what each adapter on a system is and then match that up to the device names used by WinPCap.. surely this is something I could keep in-house with lib/WinPCap?

Thanks!

Solution

  • I have a solution of sorts, just for Windows systems.

    For an adapter that I want to select, based on the network it is connected to, I can compare the IP address associated with that adapter with each of the IP addresses in objects generated by GetAdaptersInfo. If they match, then I can see whether or not the "Type" on that same object is ethernet.

    if ((pAdapterInfo->Type == MIB_IF_TYPE_ETHERNET) && (WINVER > _WIN32_WINNT_WS03))
{
}

    I also check the Windows version; since it is only from Vista (Winver 6+) onwards that IF_TYPE_IEEE80211 is returned in the adapter is wireless.

    It doesn't use WinPCap, but then again I'm not sure its possible to. Since I already am using these Windows libraries elsewhere, I figured that this is a platform-specific compromise I'll make. Hopefully that helps someone else one day!