I recently started playing with sockets into the interface packet layer,
opened via a call something like this:
s=socket(AF_INET,SOCK_PACKET,0);
I learned about this type of socket through a small sniffer (linsniff.c).
linsniff calls socket() like this:
s=socket(AF_INET,SOCK_PACKET,htons(0x800));
My question is, what is this magic number 0x800 for? I can't find it as a
#define in any of the include files in the standard include tree. Is it
necessary? In response to the inevitable question, yes, I am writing my
own sniffer, simply because I want to play with packet-level sockets and I
couldn't think of a better thing to do with them.