Question

The value is 10240 or 2800 in hex. TOTAL_LENGTH is a unsigned short.
0028 in decimal is 40 which is what I am expecting (or is at least a reasonable value).

Any ideas why I am getting a 0 instead of a 40? Thinking about reversing the bits myself but really don’t want to. xD

unsigned short total_length = ntohl(ipData->TOTAL_LENGTH);

These are the headers I am including.

#include <winsock2.h>
#include <ws2tcpip.h>

Answer 1

u_long WSAAPI ntohl(
  __in  u_long netlong
);

The result is a long, and you’re assigning it to a short. Check if it doesn’t get cut.

Also, if it’s a short, then why aren’t you using ntohs?