The PR implements the following changes:

• NSock nse_readpcap() includes VLAN tags in *l2_data, as opposed to *l3_data. Parsers can now assume that IP headers start at *l3_data even for tagged Ethernet frames.
• Libnetutil read_reply_pcap() skips over VLAN tags when calculating the offset of the next protocol.
• NSE packet.Frame:new() parses VLAN tags and capture the result in list frame.vlans. Each element is a table containing the expected fields: TPID, CPC, DEI, and VID (all in lowercase).
• NSE packet.Frame:build_ether_frame() takes an an optional parameter in the form of the list above to build 802.1Q / 802.1ad headers. Incomplete VLAN specifications use the following defaults:
  • TPID is set to C-TAG for the inner-most VLAN, S-TAG otherwise.
  • TCI fields CPC, DEI, and VID are all set to 0.