Npcap 1.81 does not show all-0 VLAN TCI headers for injected packets #791
Description
Npcap 1.81 introduced capture and injection of frames with 802.1q VLAN headers. A NET_BUFFER_LIST on the NDIS stack with an all-0 TCI value (PCP, DEI, and VID all 0) has no attribute to indicate whether it was received with such a VLAN header or not, so Npcap defaults to not including one in that case. For that reason, if a frame with such an all-0 TCI was injected via pcap_inject() or pcap_sendpacket(), it was being put in the capture queue without a VLAN header, which was not what was expected.
This issue is fixed in 454e834 by preserving any VLAN tag from injected packets that are also captured.