Sunday, October 17, 2004

Windows, oh, Windows

For the past few hours, I have been struggling with WinPcap to send RAW packets over a WAN interface. It just doesn't want to.

PacketSendPacket returns FALSE. Peeking into Packet32.c, it first checks if the adapter on which the packet is to be sent is an NDIS adapter. Since WAN adapters don't qualify as such, a write isn't even attempted. If, however, I force a WriteFile of the packet, it fails with ERROR_INVALID_HANDLE (error 6). Go figure.

I was determined not to stop there. The NPF driver's IRP_MJ_WRITE handler is NPF_Write, in Write.c. I don't know enough about kernel programming or debugging to go further than staring at the handler blankly. I suspect NdisSend (line 129) might cause the ERROR_INVALID_HANDLE, because the handle refers to an NDISWAN adapter, rather than an NDIS adapter? (I'm not very familiar with the Windows network driver architecture, either.)

Any help would be highly appreciated!

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