[tls] Mark security negotiation as a pending operation

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/tls.h

 #include <ipxe/sha1.h>
 #include <ipxe/sha256.h>
 #include <ipxe/x509.h>
+#include <ipxe/pending.h>
 
 /** A TLS header */
 struct tls_header {
 	/** Certificate validator */
 	struct interface validator;
 
-	/** Client has finished security negotiation */
-	unsigned int client_finished;
-	/** Server has finished security negotiation */
-	unsigned int server_finished;
+	/** Client security negotiation pending operation */
+	struct pending_operation client_negotiation;
+	/** Server security negotiation pending operation */
+	struct pending_operation server_negotiation;
 
 	/** TX sequence number */
 	uint64_t tx_seq;

src/net/tls.c

 #include <time.h>
 #include <errno.h>
 #include <byteswap.h>
+#include <ipxe/pending.h>
 #include <ipxe/hmac.h>
 #include <ipxe/md5.h>
 #include <ipxe/sha1.h>
  * @ret is_ready	TLS session is ready
  */
 static int tls_ready ( struct tls_session *tls ) {
-	return ( tls->client_finished && tls->server_finished );
+	return ( ( ! is_pending ( &tls->client_negotiation ) ) &&
+		 ( ! is_pending ( &tls->server_negotiation ) ) );
 }
 
 /******************************************************************************
  */
 static void tls_close ( struct tls_session *tls, int rc ) {
 
+	/* Remove pending operations, if applicable */
+	pending_put ( &tls->client_negotiation );
+	pending_put ( &tls->server_negotiation );
+
 	/* Remove process */
 	process_del ( &tls->process );
 
 		return rc;
 
 	/* Mark client as finished */
-	tls->client_finished = 1;
+	pending_put ( &tls->client_negotiation );
 
 	return 0;
 }
 	}
 
 	/* Mark server as finished */
-	tls->server_finished = 1;
+	pending_put ( &tls->server_negotiation );
 
 	/* Send notification of a window change */
 	xfer_window_changed ( &tls->plainstream );
 	tls->handshake_ctx = tls->handshake_sha256_ctx;
 	tls->tx_pending = TLS_TX_CLIENT_HELLO;
 
+	/* Add pending operations for server and client Finished messages */
+	pending_get ( &tls->client_negotiation );
+	pending_get ( &tls->server_negotiation );
+
 	/* Attach to parent interface, mortalise self, and return */
 	intf_plug_plug ( &tls->plainstream, xfer );
 	*next = &tls->cipherstream;