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.
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()orpcap_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.