res_http_websocket: Forcefully terminate on write errors.

The res_http_websocket module will currently attempt to close
the WebSocket connection if fatal cases occur, such as when
attempting to write out data and being unable to. When the
fatal cases occur the code attempts to write a WebSocket close
frame out to have the remote side close the connection. If
writing this fails then the connection is not terminated.

This change forcefully terminates the connection if the
WebSocket is to be closed but is unable to send the close frame.

ASTERISK-25312 #close

Change-Id: I10973086671cc192a76424060d9ec8e688602845

res/res_http_websocket.c

@@ -209,6 +209,17 @@ int AST_OPTIONAL_API_NAME(ast_websocket_close)(struct ast_websocket *session, ui
 
 	ao2_lock(session);
 	res = ast_careful_fwrite(session->f, session->fd, frame, 4, session->timeout);
+
+	/* If an error occurred when trying to close this connection explicitly terminate it now.
+	 * Doing so will cause the thread polling on it to wake up and terminate.
+	 */
+	if (res) {
+		fclose(session->f);
+		session->f = NULL;
+		ast_verb(2, "WebSocket connection from '%s' forcefully closed due to fatal write error\n",
+			ast_sockaddr_stringify(&session->address));
+	}
+
 	ao2_unlock(session);
 
 	return res;
@@ -366,6 +377,13 @@ static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len
 	char *rbuf = buf;
 	int sanity = 10;
 
+	ao2_lock(session);
+	if (!session->f) {
+		ao2_unlock(session);
+		errno = ECONNABORTED;
+		return -1;
+	}
+
 	for (;;) {
 		clearerr(session->f);
 		rlen = fread(rbuf, 1, xlen, session->f);
@@ -374,6 +392,7 @@ static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len
 				ast_log(LOG_WARNING, "Web socket closed abruptly\n");
 				*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
 				session->closing = 1;
+				ao2_unlock(session);
 				return -1;
 			}
 
@@ -381,6 +400,7 @@ static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len
 				ast_log(LOG_ERROR, "Error reading from web socket: %s\n", strerror(errno));
 				*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
 				session->closing = 1;
+				ao2_unlock(session);
 				return -1;
 			}
 
@@ -388,6 +408,7 @@ static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len
 				ast_log(LOG_WARNING, "Websocket seems unresponsive, disconnecting ...\n");
 				*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
 				session->closing = 1;
+				ao2_unlock(session);
 				return -1;
 			}
 		}
@@ -400,9 +421,12 @@ static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len
 			ast_log(LOG_ERROR, "ast_wait_for_input returned err: %s\n", strerror(errno));
 			*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
 			session->closing = 1;
+			ao2_unlock(session);
 			return -1;
 		}
 	}
+
+	ao2_unlock(session);
 	return 0;
 }
 
@@ -419,7 +443,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 	*fragmented = 0;
 
 	if (ws_safe_read(session, &buf[0], MIN_WS_HDR_SZ, opcode)) {
-		return 0;
+		return -1;
 	}
 	frame_size += MIN_WS_HDR_SZ;
 
@@ -437,7 +461,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 		if (options_len) {
 			/* read the rest of the header options */
 			if (ws_safe_read(session, &buf[frame_size], options_len, opcode)) {
-				return 0;
+				return -1;
 			}
 			frame_size += options_len;
 		}
@@ -466,7 +490,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 		}
 
 		if (ws_safe_read(session, *payload, *payload_len, opcode)) {
-			return 0;
+			return -1;
 		}
 
 		/* If a mask is present unmask the payload */
@@ -490,7 +514,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 					session->payload, session->payload_len, *payload_len);
 				*payload_len = 0;
 				ast_websocket_close(session, 1009);
-				return 0;
+				return -1;
 			}
 
 			session->payload = new_payload;
@@ -527,7 +551,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 		/* Make the payload available so the user can look at the reason code if they so desire */
 		if ((*payload_len) && (new_payload = ast_realloc(session->payload, *payload_len))) {
 			if (ws_safe_read(session, &buf[frame_size], (*payload_len), opcode)) {
-				return 0;
+				return -1;
 			}
 			session->payload = new_payload;
 			memcpy(session->payload, &buf[frame_size], *payload_len);