introduce timeout system

This adds a concept of timeouts for operations enforced by
connection closure if the timeout is reached.

Once a second all sockets are checked for timing out, every time
there is a service call it checks to see if a second has passed since
the last check and checks if so.

You can also call libwebsocket_service_fd() with a NULL fd to give
the timeouts a chance to be detected; if it's less than a second since
the last check it returns immediately.

Signed-off-by: Andy Green <andy@warmcat.com>

lib/client-handshake.c

@@ -92,6 +92,7 @@ libwebsocket_client_connect(struct libwebsocket_context *this,
 	wsi->state = WSI_STATE_CLIENT_UNCONNECTED;
 	wsi->pings_vs_pongs = 0;
 	wsi->protocol = NULL;
+	wsi->pending_timeout = NO_PENDING_TIMEOUT;
 
 	/* set up appropriate masking */
 

lib/libwebsockets.c

@@ -276,7 +276,7 @@ libwebsocket_service_fd(struct libwebsocket_context *this,
 {
 	unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + MAX_BROADCAST_PAYLOAD +
 						  LWS_SEND_BUFFER_POST_PADDING];
-	struct libwebsocket *wsi = wsi_from_fd(this, pollfd->fd);
+	struct libwebsocket *wsi;
 	struct libwebsocket *new_wsi;
 	int n;
 	int m;
@@ -284,6 +284,44 @@ libwebsocket_service_fd(struct libwebsocket_context *this,
 	int accept_fd;
 	unsigned int clilen;
 	struct sockaddr_in cli_addr;
+	struct timeval tv;
+
+	/*
+	 * you can call us with pollfd = NULL to just allow the once-per-second
+	 * global timeout checks; if less than a second since the last check
+	 * it returns immediately then.
+	 */
+
+	gettimeofday(&tv, NULL);
+
+	if (this->last_timeout_check_s != tv.tv_sec) {
+		this->last_timeout_check_s = tv.tv_sec;
+
+		/* global timeout check once per second */
+
+		for (n = 0; n < this->fds_count; n++) {
+			wsi = wsi_from_fd(this, this->fds[n].fd);
+			if (!wsi->pending_timeout)
+				continue;
+
+			/*
+			 * if we went beyond the allowed time, kill the
+			 * connection
+			 */
+
+			if (tv.tv_sec > wsi->pending_timeout_limit)
+				libwebsocket_close_and_free_session(this, wsi);
+		}
+	}
+
+	/* just here for timeout management? */
+
+	if (pollfd == NULL)
+		return 0;
+
+	/* no, here to service a socket descriptor */
+
+	wsi = wsi_from_fd(this, pollfd->fd);
 
 	if (wsi == NULL)
 		return 1;
@@ -336,6 +374,7 @@ libwebsocket_service_fd(struct libwebsocket_context *this,
 
 		memset(new_wsi, 0, sizeof (struct libwebsocket));
 		new_wsi->sock = accept_fd;
+		new_wsi->pending_timeout = NO_PENDING_TIMEOUT;
 
 #ifdef LWS_OPENSSL_SUPPORT
 		new_wsi->ssl = NULL;

lib/private-libwebsockets.h

@@ -166,6 +166,7 @@ struct libwebsocket_context {
 	char canonical_hostname[1024];
 	unsigned int http_proxy_port;
 	unsigned int options;
+	unsigned long last_timeout_check_s;
 
 	int fd_random;
 	
@@ -179,6 +180,12 @@ struct libwebsocket_context {
 };
 
 
+enum pending_timeout {
+	NO_PENDING_TIMEOUT = 0,
+	PENDING_TIMEOUT_ESTABLISH_WITH_SERVER,
+	PENDING_TIMEOUT_AWAITING_PING,
+};
+
 
 /*
  * This is totally opaque to code using the library.  It's exported as a
@@ -201,6 +208,8 @@ struct libwebsocket {
 						  LWS_SEND_BUFFER_POST_PADDING];
 	int rx_user_buffer_head;
 	int protocol_index_for_broadcast_proxy;
+	enum pending_timeout pending_timeout;
+	unsigned long pending_timeout_limit;
 
 	int sock;