Function tcp_usrclosed

freebsd/netinet/tcp_usrreq.c:2692–2740

* User issued close, and wish to trail through shutdown states: * if never received SYN, just forget it. If got a SYN from peer, * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. * If already got a FIN from peer, then almost done; go to LAST_ACK * state. In all other cases, have already sent FIN to peer (e.g. * after PRU_SHUTDOWN), and just have to play tedious game wa

 * We can let the user exit from the close as soon as the FIN is acked.
 */
static void
tcp_usrclosed(struct tcpcb *tp)
{

	NET_EPOCH_ASSERT();
	INP_WLOCK_ASSERT(tp->t_inpcb);

	switch (tp->t_state) {
	case TCPS_LISTEN:
#ifdef TCP_OFFLOAD
		tcp_offload_listen_stop(tp);
#endif
		tcp_state_change(tp, TCPS_CLOSED);
		/* FALLTHROUGH */
	case TCPS_CLOSED:
		tp = tcp_close(tp);
		/*
		 * tcp_close() should never return NULL here as the socket is
		 * still open.
		 */
		KASSERT(tp != NULL,
		    ("tcp_usrclosed: tcp_close() returned NULL"));
		break;

	case TCPS_SYN_SENT:
	case TCPS_SYN_RECEIVED:
		tp->t_flags |= TF_NEEDFIN;
		break;

	case TCPS_ESTABLISHED:
		tcp_state_change(tp, TCPS_FIN_WAIT_1);
		break;

	case TCPS_CLOSE_WAIT:
		tcp_state_change(tp, TCPS_LAST_ACK);
		break;
	}
	if (tp->t_state >= TCPS_FIN_WAIT_2) {
		soisdisconnected(tp->t_inpcb->inp_socket);
		/* Prevent the connection hanging in FIN_WAIT_2 forever. */
		if (tp->t_state == TCPS_FIN_WAIT_2) {
			int timeout;

			timeout = (tcp_fast_finwait2_recycle) ?
			    tcp_finwait2_timeout : TP_MAXIDLE(tp);
			tcp_timer_activate(tp, TT_2MSL, timeout);
		}
	}
}

#ifdef DDB
static void