#include <u.h>
#include <libc.h>

typedef struct Tcphdr Tcphdr;
struct Tcphdr {
	int		tid;
	int		proto;
	int		len;
	int		sa;
};

Tcphdr*
tcphdr(uchar *buf, int blen)
{
	if( blen != 7 || buf == 0)
		return 0;

	Tcphdr th;
	memset(&th, 0, sizeof(Tcphdr));

	th.tid   = buf[0] << 8 | buf[1] << 0;
	th.proto = buf[2] << 8 | buf[3] << 0;
	th.len   = buf[4] << 8 | buf[5] << 0;
	th.sa    = buf[6] << 0;

	return &th;
}

void
main(int argc, char *argv[])
{
	Tcphdr *th;
	uchar buf[512] = {0x00, 0x06, 0x00, 0x05, 0x00, 0x08, 0x16};

	th = tcphdr(buf, 7);

	print("tid: %d \n", th->tid);
	print("proto: %d \n", th->proto);
	print("len: %d \n", th->len);
	print("sa: %d \n", th->sa);

	exits(nil);
}