Diff: src/aws_iot_mqtt_client_yield.c

Revision:

0:082731ede69f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/aws_iot_mqtt_client_yield.c	Wed May 30 20:59:51 2018 +0000
@@ -0,0 +1,322 @@
+/*
+* Copyright 2015-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+*
+* Licensed under the Apache License, Version 2.0 (the "License").
+* You may not use this file except in compliance with the License.
+* A copy of the License is located at
+*
+* http://aws.amazon.com/apache2.0
+*
+* or in the "license" file accompanying this file. This file is distributed
+* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+* express or implied. See the License for the specific language governing
+* permissions and limitations under the License.
+*/
+
+// Based on Eclipse Paho.
+/*******************************************************************************
+ * Copyright (c) 2014 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    http://www.eclipse.org/legal/epl-v10.html
+ * and the Eclipse Distribution License is available at
+ *   http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *    Allan Stockdill-Mander/Ian Craggs - initial API and implementation and/or initial documentation
+ *******************************************************************************/
+
+/**
+ * @file aws_iot_mqtt_client_yield.c
+ * @brief MQTT client yield API definitions
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "aws_iot_mqtt_client_common_internal.h"
+
+/**
+  * This is for the case when the aws_iot_mqtt_internal_send_packet Fails.
+  */
+static void _aws_iot_mqtt_force_client_disconnect(AWS_IoT_Client *pClient) {
+    pClient->clientStatus.clientState = CLIENT_STATE_DISCONNECTED_ERROR;
+    pClient->networkStack.disconnect(&(pClient->networkStack));
+    pClient->networkStack.destroy(&(pClient->networkStack));
+}
+
+static IoT_Error_t _aws_iot_mqtt_handle_disconnect(AWS_IoT_Client *pClient) {
+    IoT_Error_t rc;
+
+    FUNC_ENTRY;
+//printf("JMF: called aws_iot_mqtt_handle_disconnect\n");
+    rc = aws_iot_mqtt_disconnect(pClient);
+    if(rc != AWS_SUCCESS) {
+        // If the aws_iot_mqtt_internal_send_packet prevents us from sending a disconnect packet then we have to clean the stack
+        _aws_iot_mqtt_force_client_disconnect(pClient);
+    }
+
+    if(NULL != pClient->clientData.disconnectHandler) {
+        pClient->clientData.disconnectHandler(pClient, pClient->clientData.disconnectHandlerData);
+    }
+
+    /* Reset to 0 since this was not a manual disconnect */
+    pClient->clientStatus.clientState = CLIENT_STATE_DISCONNECTED_ERROR;
+//printf("JMF: %s:%d\n",__FILE__,__LINE__);
+    FUNC_EXIT_RC(NETWORK_DISCONNECTED_ERROR);
+}
+
+
+static IoT_Error_t _aws_iot_mqtt_handle_reconnect(AWS_IoT_Client *pClient) {
+    IoT_Error_t rc;
+
+    FUNC_ENTRY;
+
+    if(!has_timer_expired(&(pClient->reconnectDelayTimer))) {
+        /* awsTimer has not expired. Not time to attempt reconnect yet.
+         * Return attempting reconnect */
+        FUNC_EXIT_RC(NETWORK_ATTEMPTING_RECONNECT);
+    }
+
+    rc = NETWORK_PHYSICAL_LAYER_DISCONNECTED;
+    if(NULL != pClient->networkStack.isConnected) {
+        rc = pClient->networkStack.isConnected(&(pClient->networkStack));
+    }
+
+    if(NETWORK_PHYSICAL_LAYER_CONNECTED == rc) {
+        rc = aws_iot_mqtt_attempt_reconnect(pClient);
+        if(NETWORK_RECONNECTED == rc) {
+            rc = aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTED_IDLE,
+                                               CLIENT_STATE_CONNECTED_YIELD_IN_PROGRESS);
+            if(AWS_SUCCESS != rc) {
+                FUNC_EXIT_RC(rc);
+            }
+            FUNC_EXIT_RC(NETWORK_RECONNECTED);
+        }
+    }
+
+    pClient->clientData.currentReconnectWaitInterval *= 2;
+
+    if(AWS_IOT_MQTT_MAX_RECONNECT_WAIT_INTERVAL < pClient->clientData.currentReconnectWaitInterval) {
+        FUNC_EXIT_RC(NETWORK_RECONNECT_TIMED_OUT_ERROR);
+    }
+    countdown_ms(&(pClient->reconnectDelayTimer), pClient->clientData.currentReconnectWaitInterval);
+    FUNC_EXIT_RC(rc);
+}
+
+static IoT_Error_t _aws_iot_mqtt_keep_alive(AWS_IoT_Client *pClient) {
+    IoT_Error_t rc = AWS_SUCCESS;
+    awsTimer timer;
+    size_t serialized_len;
+
+    FUNC_ENTRY;
+
+    if(NULL == pClient) {
+        FUNC_EXIT_RC(NULL_VALUE_ERROR);
+    }
+
+    if(0 == pClient->clientData.keepAliveInterval) {
+        FUNC_EXIT_RC(AWS_SUCCESS);
+    }
+
+    if(!has_timer_expired(&pClient->pingTimer)) {
+        FUNC_EXIT_RC(AWS_SUCCESS);
+    }
+
+    if(pClient->clientStatus.isPingOutstanding) {
+//printf("JMF1\n");
+        rc = _aws_iot_mqtt_handle_disconnect(pClient);
+        FUNC_EXIT_RC(rc);
+    }
+
+    /* there is no ping outstanding - send one */
+    init_timer(&timer);
+
+    countdown_ms(&timer, pClient->clientData.commandTimeoutMs);
+    serialized_len = 0;
+    rc = aws_iot_mqtt_internal_serialize_zero(pClient->clientData.writeBuf, pClient->clientData.writeBufSize,
+                                              PINGREQ, &serialized_len);
+    if(AWS_SUCCESS != rc) {
+        FUNC_EXIT_RC(rc);
+    }
+
+    /* send the ping packet */
+    rc = aws_iot_mqtt_internal_send_packet(pClient, serialized_len, &timer);
+    if(AWS_SUCCESS != rc) {
+        //If sending a PING fails we can no longer determine if we are connected.  In this case we decide we are disconnected and begin reconnection attempts
+//printf("JMF2\n");
+        rc = _aws_iot_mqtt_handle_disconnect(pClient);
+        FUNC_EXIT_RC(rc);
+    }
+
+    pClient->clientStatus.isPingOutstanding = true;
+    /* start a timer to wait for PINGRESP from server */
+    countdown_sec(&pClient->pingTimer, pClient->clientData.keepAliveInterval);
+
+    FUNC_EXIT_RC(AWS_SUCCESS);
+}
+
+/**
+ * @brief Yield to the MQTT client
+ *
+ * Called to yield the current thread to the underlying MQTT client.  This time is used by
+ * the MQTT client to manage PING requests to monitor the health of the TCP connection as
+ * well as periodically check the socket receive buffer for subscribe messages.  Yield()
+ * must be called at a rate faster than the keepalive interval.  It must also be called
+ * at a rate faster than the incoming message rate as this is the only way the client receives
+ * processing time to manage incoming messages.
+ * This is the internal function which is called by the yield API to perform the operation.
+ * Not meant to be called directly as it doesn't do validations or client state changes
+ *
+ * @param pClient Reference to the IoT Client
+ * @param timeout_ms Maximum number of milliseconds to pass thread execution to the client.
+ *
+ * @return An IoT Error Type defining successful/failed client processing.
+ *         If this call results in an error it is likely the MQTT connection has dropped.
+ *         iot_is_mqtt_connected can be called to confirm.
+ */
+static IoT_Error_t _aws_iot_mqtt_internal_yield(AWS_IoT_Client *pClient, uint32_t timeout_ms) {
+    IoT_Error_t yieldRc = AWS_SUCCESS;
+
+    uint8_t packet_type;
+    ClientState clientState;
+    awsTimer timer;
+    init_timer(&timer);
+    countdown_ms(&timer, timeout_ms);
+//printf("JMF: called internal_yeld\n");
+    FUNC_ENTRY;
+
+    // evaluate timeout at the end of the loop to make sure the actual yield runs at least once
+    do {
+        clientState = aws_iot_mqtt_get_client_state(pClient);
+        if(CLIENT_STATE_PENDING_RECONNECT == clientState) {
+//printf("JMF: pending_reconnect\n");
+            if(AWS_IOT_MQTT_MAX_RECONNECT_WAIT_INTERVAL < pClient->clientData.currentReconnectWaitInterval) {
+                yieldRc = NETWORK_RECONNECT_TIMED_OUT_ERROR;
+                break;
+            }
+//printf("JMF: do reconnect\n");
+            yieldRc = _aws_iot_mqtt_handle_reconnect(pClient);
+            /* Network reconnect attempted, check if yield timer expired before
+             * doing anything else */
+            continue;
+        }
+
+//printf("JMF: do internal_cycle_read \n");
+        yieldRc = aws_iot_mqtt_internal_cycle_read(pClient, &timer, &packet_type);
+        if(AWS_SUCCESS == yieldRc) {
+            yieldRc = _aws_iot_mqtt_keep_alive(pClient);
+        } else {
+            // SSL read and write errors are terminal, connection must be closed and retried
+            if(NETWORK_SSL_READ_ERROR == yieldRc || NETWORK_SSL_READ_TIMEOUT_ERROR == yieldRc
+                || NETWORK_SSL_WRITE_ERROR == yieldRc || NETWORK_SSL_WRITE_TIMEOUT_ERROR == yieldRc) {
+//printf("JMF3 %d\n",yieldRc);
+                yieldRc = _aws_iot_mqtt_handle_disconnect(pClient);
+            }
+        }
+
+//printf("JMF: keepalive said: %d \n", yieldRc);
+        if(NETWORK_DISCONNECTED_ERROR == yieldRc) {
+//printf("JMF: was a disconnect erro \n");
+            pClient->clientData.counterNetworkDisconnected++;
+            if(1 == pClient->clientStatus.isAutoReconnectEnabled) {
+                yieldRc = aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_DISCONNECTED_ERROR,
+                                                        CLIENT_STATE_PENDING_RECONNECT);
+                if(AWS_SUCCESS != yieldRc) {
+                    FUNC_EXIT_RC(yieldRc);
+                }
+
+                pClient->clientData.currentReconnectWaitInterval = AWS_IOT_MQTT_MIN_RECONNECT_WAIT_INTERVAL;
+                countdown_ms(&(pClient->reconnectDelayTimer), pClient->clientData.currentReconnectWaitInterval);
+                /* Depending on timer values, it is possible that yield timer has expired
+                 * Set to rc to attempting reconnect to inform client that autoreconnect
+                 * attempt has started */
+                yieldRc = NETWORK_ATTEMPTING_RECONNECT;
+            } else {
+                break;
+            }
+        } else if(AWS_SUCCESS != yieldRc) {
+            break;
+        }
+    } while(!has_timer_expired(&timer));
+//printf("JMF: exit internal_yield with %d\n",yieldRc);
+
+    FUNC_EXIT_RC(yieldRc);
+}
+
+/**
+ * @brief Yield to the MQTT client
+ *
+ * Called to yield the current thread to the underlying MQTT client.  This time is used by
+ * the MQTT client to manage PING requests to monitor the health of the TCP connection as
+ * well as periodically check the socket receive buffer for subscribe messages.  Yield()
+ * must be called at a rate faster than the keepalive interval.  It must also be called
+ * at a rate faster than the incoming message rate as this is the only way the client receives
+ * processing time to manage incoming messages.
+ * This is the outer function which does the validations and calls the internal yield above
+ * to perform the actual operation. It is also responsible for client state changes
+ *
+ * @param pClient Reference to the IoT Client
+ * @param timeout_ms Maximum number of milliseconds to pass thread execution to the client.
+ *
+ * @return An IoT Error Type defining successful/failed client processing.
+ *         If this call results in an error it is likely the MQTT connection has dropped.
+ *         iot_is_mqtt_connected can be called to confirm.
+ */
+IoT_Error_t aws_iot_mqtt_yield(AWS_IoT_Client *pClient, uint32_t timeout_ms) {
+    IoT_Error_t rc, yieldRc;
+    ClientState clientState;
+
+    if(NULL == pClient || 0 == timeout_ms) {
+        FUNC_EXIT_RC(NULL_VALUE_ERROR);
+    }
+
+    clientState = aws_iot_mqtt_get_client_state(pClient);
+    /* Check if network was manually disconnected */
+    if(CLIENT_STATE_DISCONNECTED_MANUALLY == clientState) {
+        FUNC_EXIT_RC(NETWORK_MANUALLY_DISCONNECTED);
+    }
+
+    /* If we are in the pending reconnect state, skip other checks.
+     * Pending reconnect state is only set when auto-reconnect is enabled */
+    if(CLIENT_STATE_PENDING_RECONNECT != clientState) {
+        /* Check if network is disconnected and auto-reconnect is not enabled */
+        if(!aws_iot_mqtt_is_client_connected(pClient)) {
+//printf("JMF: %s:%d\n",__FILE__,__LINE__);
+            FUNC_EXIT_RC(NETWORK_DISCONNECTED_ERROR);
+        }
+
+        /* Check if client is idle, if not another operation is in progress and we should return */
+        if(CLIENT_STATE_CONNECTED_IDLE != clientState) {
+            FUNC_EXIT_RC(MQTT_CLIENT_NOT_IDLE_ERROR);
+        }
+
+        rc = aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTED_IDLE,
+                                           CLIENT_STATE_CONNECTED_YIELD_IN_PROGRESS);
+        if(AWS_SUCCESS != rc) {
+            FUNC_EXIT_RC(rc);
+        }
+    }
+
+    yieldRc = _aws_iot_mqtt_internal_yield(pClient, timeout_ms);
+
+    if(NETWORK_DISCONNECTED_ERROR != yieldRc && NETWORK_ATTEMPTING_RECONNECT != yieldRc) {
+        rc = aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTED_YIELD_IN_PROGRESS,
+                                           CLIENT_STATE_CONNECTED_IDLE);
+        if(AWS_SUCCESS == yieldRc && AWS_SUCCESS != rc) {
+            yieldRc = rc;
+        }
+    }
+
+    FUNC_EXIT_RC(yieldRc);
+}
+
+#ifdef __cplusplus
+}
+#endif
+