server: change prototype of add_service()

To easily add new methods to a service, pass all the methods
through a struct.
While there, drop the typedef for the methods and add currently
unused new methods to support keep-alive and connections during
keep-alive.

No change in functionality.

Change-Id: I2b5e7140db95021f6e7201e9d631ee340c60b453
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6838
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Tested-by: jenkins

src/server/gdb_server.c

@@ -3657,6 +3657,15 @@ static int gdb_input(struct connection *connection)
 	return ERROR_OK;
 }
 
+static const struct service_driver gdb_service_driver = {
+	.name = "gdb",
+	.new_connection_during_keep_alive_handler = NULL,
+	.new_connection_handler = gdb_new_connection,
+	.input_handler = gdb_input,
+	.connection_closed_handler = gdb_connection_closed,
+	.keep_client_alive_handler = NULL,
+};
+
 static int gdb_target_start(struct target *target, const char *port)
 {
 	struct gdb_service *gdb_service;
@@ -3673,9 +3682,7 @@ static int gdb_target_start(struct target *target, const char *port)
 	gdb_service->core[1] = -1;
 	target->gdb_service = gdb_service;
 
-	ret = add_service("gdb",
-			port, target->gdb_max_connections, &gdb_new_connection, &gdb_input,
-			&gdb_connection_closed, gdb_service);
+	ret = add_service(&gdb_service_driver, port, target->gdb_max_connections, gdb_service);
 	/* initialize all targets gdb service with the same pointer */
 	{
 		struct target_list *head;

src/server/ipdbg.c

@@ -587,6 +587,15 @@ static int ipdbg_on_connection_closed(struct connection *connection)
 	return ipdbg_stop_polling(connection->service->priv);
 }
 
+static const struct service_driver ipdbg_service_driver = {
+	.name = "ipdbg",
+	.new_connection_during_keep_alive_handler = NULL,
+	.new_connection_handler = ipdbg_on_new_connection,
+	.input_handler = ipdbg_on_connection_input,
+	.connection_closed_handler = ipdbg_on_connection_closed,
+	.keep_client_alive_handler = NULL,
+};
+
 static int ipdbg_start(uint16_t port, struct jtag_tap *tap, uint32_t user_instruction,
 					uint8_t data_register_length, struct ipdbg_virtual_ir_info *virtual_ir, uint8_t tool)
 {
@@ -618,8 +627,7 @@ static int ipdbg_start(uint16_t port, struct jtag_tap *tap, uint32_t user_instru
 
 	char port_str_buffer[IPDBG_TCP_PORT_STR_MAX_LENGTH];
 	snprintf(port_str_buffer, IPDBG_TCP_PORT_STR_MAX_LENGTH, "%u", port);
-	retval = add_service("ipdbg", port_str_buffer, 1, &ipdbg_on_new_connection,
-		&ipdbg_on_connection_input, &ipdbg_on_connection_closed, service);
+	retval = add_service(&ipdbg_service_driver, port_str_buffer, 1, service);
 	if (retval == ERROR_OK) {
 		ipdbg_add_service(service);
 		if (hub->active_services == 0 && hub->active_connections == 0)

src/server/rtt_server.c

@@ -110,6 +110,15 @@ static int rtt_input(struct connection *connection)
 	return ERROR_OK;
 }
 
+static const struct service_driver rtt_service_driver = {
+	.name = "rtt",
+	.new_connection_during_keep_alive_handler = NULL,
+	.new_connection_handler = rtt_new_connection,
+	.input_handler = rtt_input,
+	.connection_closed_handler = rtt_connection_closed,
+	.keep_client_alive_handler = NULL,
+};
+
 COMMAND_HANDLER(handle_rtt_start_command)
 {
 	int ret;
@@ -125,8 +134,7 @@ COMMAND_HANDLER(handle_rtt_start_command)
 
 	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], service->channel);
 
-	ret = add_service("rtt", CMD_ARGV[0], CONNECTION_LIMIT_UNLIMITED,
-		rtt_new_connection, rtt_input, rtt_connection_closed, service);
+	ret = add_service(&rtt_service_driver, CMD_ARGV[0], CONNECTION_LIMIT_UNLIMITED, service);
 
 	if (ret != ERROR_OK) {
 		free(service);

src/server/server.c

@@ -205,13 +205,8 @@ static void free_service(struct service *c)
 	free(c);
 }
 
-int add_service(char *name,
-	const char *port,
-	int max_connections,
-	new_connection_handler_t new_connection_handler,
-	input_handler_t input_handler,
-	connection_closed_handler_t connection_closed_handler,
-	void *priv)
+int add_service(const struct service_driver *driver, const char *port,
+		int max_connections, void *priv)
 {
 	struct service *c, **p;
 	struct hostent *hp;
@@ -219,14 +214,16 @@ int add_service(char *name,
 
 	c = malloc(sizeof(struct service));
 
-	c->name = strdup(name);
+	c->name = strdup(driver->name);
 	c->port = strdup(port);
 	c->max_connections = 1;	/* Only TCP/IP ports can support more than one connection */
 	c->fd = -1;
 	c->connections = NULL;
-	c->new_connection = new_connection_handler;
-	c->input = input_handler;
-	c->connection_closed = connection_closed_handler;
+	c->new_connection_during_keep_alive = driver->new_connection_during_keep_alive_handler;
+	c->new_connection = driver->new_connection_handler;
+	c->input = driver->input_handler;
+	c->connection_closed = driver->connection_closed_handler;
+	c->keep_client_alive = driver->keep_client_alive_handler;
 	c->priv = priv;
 	c->next = NULL;
 	long portnumber;
@@ -278,7 +275,7 @@ int add_service(char *name,
 		c->sin.sin_port = htons(c->portnumber);
 
 		if (bind(c->fd, (struct sockaddr *)&c->sin, sizeof(c->sin)) == -1) {
-			LOG_ERROR("couldn't bind %s to socket on port %d: %s", name, c->portnumber, strerror(errno));
+			LOG_ERROR("couldn't bind %s to socket on port %d: %s", c->name, c->portnumber, strerror(errno));
 			close_socket(c->fd);
 			free_service(c);
 			return ERROR_FAIL;
@@ -309,7 +306,7 @@ int add_service(char *name,
 		socklen_t addr_in_size = sizeof(addr_in);
 		if (getsockname(c->fd, (struct sockaddr *)&addr_in, &addr_in_size) == 0)
 			LOG_INFO("Listening on port %hu for %s connections",
-				 ntohs(addr_in.sin_port), name);
+				 ntohs(addr_in.sin_port), c->name);
 	} else if (c->type == CONNECTION_STDINOUT) {
 		c->fd = fileno(stdin);
 

src/server/server.h

@@ -55,9 +55,25 @@ struct connection {
 	struct connection *next;
 };
 
-typedef int (*new_connection_handler_t)(struct connection *connection);
-typedef int (*input_handler_t)(struct connection *connection);
-typedef int (*connection_closed_handler_t)(struct connection *connection);
+struct service_driver {
+	/** the name of the server */
+	const char *name;
+	/** optional minimal setup to accept a connection during keep-alive */
+	int (*new_connection_during_keep_alive_handler)(struct connection *connection);
+	/**
+	 * complete code to accept a new connection.
+	 * If 'new_connection_during_keep_alive_handler' above is present, this can be
+	 * either called alone during the server_loop, or after the function above.
+	 * Check the implementation in gdb_server.
+	 * */
+	int (*new_connection_handler)(struct connection *connection);
+	/** callback to handle incoming data */
+	int (*input_handler)(struct connection *connection);
+	/** callback to tear down the connection */
+	int (*connection_closed_handler)(struct connection *connection);
+	/** called periodically to send keep-alive messages on the connection */
+	void (*keep_client_alive_handler)(struct connection *connection);
+};
 
 struct service {
 	char *name;
@@ -68,17 +84,17 @@ struct service {
 	struct sockaddr_in sin;
 	int max_connections;
 	struct connection *connections;
-	new_connection_handler_t new_connection;
-	input_handler_t input;
-	connection_closed_handler_t connection_closed;
+	int (*new_connection_during_keep_alive)(struct connection *connection);
+	int (*new_connection)(struct connection *connection);
+	int (*input)(struct connection *connection);
+	int (*connection_closed)(struct connection *connection);
+	void (*keep_client_alive)(struct connection *connection);
 	void *priv;
 	struct service *next;
 };
 
-int add_service(char *name, const char *port,
-		int max_connections, new_connection_handler_t new_connection_handler,
-		input_handler_t in_handler, connection_closed_handler_t close_handler,
-		void *priv);
+int add_service(const struct service_driver *driver, const char *port,
+		int max_connections, void *priv);
 int remove_service(const char *name, const char *port);
 
 int server_host_os_entry(void);

src/server/tcl_server.c

@@ -276,6 +276,15 @@ static int tcl_closed(struct connection *connection)
 	return ERROR_OK;
 }
 
+static const struct service_driver tcl_service_driver = {
+	.name = "tcl",
+	.new_connection_during_keep_alive_handler = NULL,
+	.new_connection_handler = tcl_new_connection,
+	.input_handler = tcl_input,
+	.connection_closed_handler = tcl_closed,
+	.keep_client_alive_handler = NULL,
+};
+
 int tcl_init(void)
 {
 	if (strcmp(tcl_port, "disabled") == 0) {
@@ -283,9 +292,7 @@ int tcl_init(void)
 		return ERROR_OK;
 	}
 
-	return add_service("tcl", tcl_port, CONNECTION_LIMIT_UNLIMITED,
-		&tcl_new_connection, &tcl_input,
-		&tcl_closed, NULL);
+	return add_service(&tcl_service_driver, tcl_port, CONNECTION_LIMIT_UNLIMITED, NULL);
 }
 
 COMMAND_HANDLER(handle_tcl_port_command)

src/server/telnet_server.c

@@ -946,6 +946,15 @@ static int telnet_connection_closed(struct connection *connection)
 	return ERROR_OK;
 }
 
+static const struct service_driver telnet_service_driver = {
+	.name = "telnet",
+	.new_connection_during_keep_alive_handler = NULL,
+	.new_connection_handler = telnet_new_connection,
+	.input_handler = telnet_input,
+	.connection_closed_handler = telnet_connection_closed,
+	.keep_client_alive_handler = NULL,
+};
+
 int telnet_init(char *banner)
 {
 	if (strcmp(telnet_port, "disabled") == 0) {
@@ -963,8 +972,7 @@ int telnet_init(char *banner)
 
 	telnet_service->banner = banner;
 
-	int ret = add_service("telnet", telnet_port, CONNECTION_LIMIT_UNLIMITED,
-		telnet_new_connection, telnet_input, telnet_connection_closed,
+	int ret = add_service(&telnet_service_driver, telnet_port, CONNECTION_LIMIT_UNLIMITED,
 		telnet_service);
 
 	if (ret != ERROR_OK) {