Function tcp_drop

freebsd/netinet/tcp_subr.c:1893–1912

* Drop a TCP connection, reporting * the specified error. If connection is synchronized, * then send a RST to peer. */

 * then send a RST to peer.
 */
struct tcpcb *
tcp_drop(struct tcpcb *tp, int errno)
{
	struct socket *so = tp->t_inpcb->inp_socket;

	NET_EPOCH_ASSERT();
	INP_INFO_LOCK_ASSERT(&V_tcbinfo);
	INP_WLOCK_ASSERT(tp->t_inpcb);

	if (TCPS_HAVERCVDSYN(tp->t_state)) {
		tcp_state_change(tp, TCPS_CLOSED);
		(void) tp->t_fb->tfb_tcp_output(tp);
		TCPSTAT_INC(tcps_drops);
	} else
		TCPSTAT_INC(tcps_conndrops);
	if (errno == ETIMEDOUT && tp->t_softerror)
		errno = tp->t_softerror;
	so->so_error = errno;
	return (tcp_close(tp));
}

void
tcp_discardcb(struct tcpcb *tp)