/* TCP timeout routines */
#include <stdio.h>
#include "machdep.h"
#include "timer.h"
#include "mbuf.h"
#include "netuser.h"
#include "internet.h"
#include "ip.h"
#include "tcp.h"

/* Timer timeout */
void
tcp_timeout(arg)
int *arg;
{
	register struct tcb *tcb;

	tcb = (struct tcb *)arg;
	switch(tcb->state){
	case TIME_WAIT:		/* 2MSL timer has expired */
		close_self(tcb,NORMAL);
		break;
	default:		/* Retransmission timer has expired */
		if(tcb->retry < RETRY){
			tcb->retry++;
			tcb->snd.ptr = tcb->snd.una;
			/* Back off on retransmission timer;
			 * on closed window probes, limit it to
			 * BACKOFF x the current round trip estimate
			 */
			tcb->timer.start <<= 1;
			if(tcb->snd.wnd == 0)
				tcb->timer.start =
				 min(tcb->timer.start,BACKOFF*tcb->srtt/MSPTICK);
			tcp_output(tcb);
		} else {
			/* Give up */
			close_self(tcb,TIMEOUT);
		}
	}
}