I have just started using WinPcap (actually, Beesync's PacketX), and boy am I having fun. However, I have come to realize that, to send packets, I will need to calculate at least three checksums for each packet: one at layer 2, one at layer 3, and one at layer 4. Calculating these checksums will add huge overhead--at least three separate do/while loops per packet transmitted. Although the code for checksum calculation is short (about ten lines, I guess), the overhead is still so great that RFC 1071 recommends taking advantage of "every machine-specific trick" to optimize performance. As an intermediate VB programmer, such machine-level expertise is currently beyond me, so it would be nice (in the extreme) if such functions were built into WinPCap. It would be great if I could pass WinPcap a pointer to a byte array and have it return a checksum value against the array. Do you think you could be convinced to add such functionality into the library?
-- Eric Robinson Network Analyst State of Nevada DOT
