Modify data-xfer semantics: it is no longer necessary to call one of

request(), seek() or deliver_xxx() in order to start the data flow.
Autonomous generators must be genuinely autonomous (having their own
process), or otherwise arrange to be called.  TCP does this by
starting the retry timer immediately.

Add some debugging statements.

src/net/tcp.c

 	DBGC ( tcp, "TCP %p allocated\n", tcp );
 	memset ( tcp, 0, sizeof ( *tcp ) );
 	xfer_init ( &tcp->xfer, &tcp_xfer_operations, &tcp->refcnt );
-	tcp->tcp_state = tcp->prev_tcp_state = TCP_CLOSED;
+	tcp->prev_tcp_state = TCP_CLOSED;
+	tcp->tcp_state = TCP_STATE_SENT ( TCP_SYN );
+	tcp_dump_state ( tcp );
 	tcp->snd_seq = random();
 	INIT_LIST_HEAD ( &tcp->queue );
 	tcp->timer.expired = tcp_expired;
 	if ( ( rc = tcp_bind ( tcp, bind_port ) ) != 0 )
 		goto err;
 
+	/* Start timer to initiate SYN */
+	start_timer ( &tcp->timer );
+
 	/* Attach parent interface, transfer reference to connection
 	 * list and return
 	 */
 	size_t window;
 	int rc;
 
+	/* If retransmission timer is already running, do nothing */
+	if ( timer_running ( &tcp->timer ) )
+		return 0;
+
 	/* Calculate both the actual (payload) and sequence space
 	 * lengths that we wish to transmit.
 	 */
  ***************************************************************************
  */
 
-/**
- * Ensure TCP connection has started
- *
- * @v tcp		TCP connection
- */
-static void tcp_ensure_started ( struct tcp_connection *tcp ) {
-	if ( ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_SYN ) ) ) {
-		tcp->tcp_state = TCP_SYN_SENT;
-		tcp_dump_state ( tcp );
-		tcp_xmit ( tcp, 0 );
-	}
-}
-
 /**
  * Close interface
  *
 	tcp_xmit ( tcp, 0 );
 }
 
-/**
- * Request data
- *
- * @v xfer		Data transfer interface
- * @v offset		Offset to new position
- * @v whence		Basis for new position
- * @v len		Length of requested data
- * @ret rc		Return status code
- */
-static int tcp_xfer_request ( struct xfer_interface *xfer,
-			      off_t offset __unused, int whence __unused,
-			      size_t len __unused ) {
-	struct tcp_connection *tcp =
-		container_of ( xfer, struct tcp_connection, xfer );
-
-	/* Ensure connection has been started */
-	tcp_ensure_started ( tcp );
-
-	return 0;
-}
-
 /**
  * Seek to position
  *
 	struct tcp_connection *tcp =
 		container_of ( xfer, struct tcp_connection, xfer );
 
-	/* Ensure connection has been started */
-	tcp_ensure_started ( tcp );
-
 	/* TCP doesn't support seeking to arbitrary positions */
 	if ( ( whence != SEEK_CUR ) || ( offset != 0 ) )
 		return -EINVAL;
 	struct tcp_connection *tcp =
 		container_of ( xfer, struct tcp_connection, xfer );
 
-	/* Ensure connection has been started */
-	tcp_ensure_started ( tcp );
-
 	/* Enqueue packet */
 	list_add_tail ( &iobuf->list, &tcp->queue );
 
 static struct xfer_interface_operations tcp_xfer_operations = {
 	.close		= tcp_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.request	= tcp_xfer_request,
+	.request	= ignore_xfer_request,
 	.seek		= tcp_xfer_seek,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= tcp_xfer_deliver_iob,