Unfortunately it is not so easy, as there may be many ethernet packets for each TCP/IP packet.
Well, yes, IP packet can be fragmented and you may have to gather all fragments before processing the packet. However, fragmented IP packets are rather rare in modern networks, also these packets are recommended to be blocked by firewalls. Basically, I don’t think you will ever meet fragmented TCP packet, but it is still possible to generate fragmented ICMP or UDP packets.
Can I implement this with WinpkFilter? Is there a better way?
Am I missing something in the walkthrough provided above?
How do I buffer multiple ethernet packets and (after processing) send them to their intended destination using WinpkFilter? I know how it works for one packet at a time, but what about multiple?
In general the approach is correct. Sending multiply packets does not differ from sending a single one.