Connect and publish packets

src/MQTTSNConnectClient.c

@@ -0,0 +1,153 @@
+/*******************************************************************************
+ * 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:
+ *    Ian Craggs - initial API and implementation and/or initial documentation
+ *******************************************************************************/
+
+#include "MQTTSNPacket.h"
+#include "StackTrace.h"
+
+#include <string.h>
+
+/**
+  * Determines the length of the MQTT connect packet that would be produced using the supplied connect options.
+  * @param options the options to be used to build the connect packet
+  * @return the length of buffer needed to contain the serialized version of the packet
+  */
+int MQTTSNSerialize_connectLength(MQTTSNPacket_connectData* options)
+{
+	int len = 0;
+
+	FUNC_ENTRY;
+	len = 5 + MQTTstrlen(options->clientID);
+	FUNC_EXIT_RC(len);
+	return len;
+}
+
+
+/**
+  * Serializes the connect options into the buffer.
+  * @param buf the buffer into which the packet will be serialized
+  * @param len the length in bytes of the supplied buffer
+  * @param options the options to be used to build the connect packet
+  * @return serialized length, or error if 0
+  */
+int MQTTSNSerialize_connect(unsigned char* buf, int buflen, MQTTSNPacket_connectData* options)
+{
+	unsigned char *ptr = buf;
+	MQTTSNFlags flags;
+	int len = 0;
+	int rc = -1;
+
+	FUNC_ENTRY;
+	if ((len = MQTTSNPacket_len(MQTTSNSerialize_connectLength(options))) > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len); /* write length */
+	writeChar(&ptr, MQTTSN_CONNECT);      /* write message type */
+
+	flags.all = 0;
+	flags.bits.cleanSession = options->cleansession;
+	flags.bits.will = options->willFlag;
+	writeChar(&ptr, flags.all);
+	writeChar(&ptr, 0x01);                 /* protocol ID */
+	writeInt(&ptr, options->duration);
+	writeMQTTSNString(&ptr, options->clientID);
+
+	rc = ptr - buf;
+
+	exit: FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+/**
+  * Deserializes the supplied (wire) buffer into connack data - return code
+  * @param connack_rc returned integer value of the connack return code
+  * @param buf the raw buffer data, of the correct length determined by the remaining length field
+  * @param len the length in bytes of the data in the supplied buffer
+  * @return error code.  1 is success, 0 is failure
+  */
+int MQTTSNDeserialize_connack(int* connack_rc, unsigned char* buf, int buflen)
+{
+	unsigned char* curdata = buf;
+	unsigned char* enddata = NULL;
+	int rc = 0;
+	int mylen;
+
+	FUNC_ENTRY;
+	curdata += (rc = MQTTSNPacket_decodeBuf(curdata, &mylen)); /* read length */
+	enddata = buf + mylen;
+	if (enddata - curdata < 2)
+		goto exit;
+
+	if (readChar(&curdata) != MQTTSN_CONNACK)
+		goto exit;
+
+	*connack_rc = readInt(&curdata);
+
+	rc = 1;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+/**
+  * Determines the length of the MQTT disconnect packet (without length field)
+  * @param duration the parameter used for the disconnect
+  * @return the length of buffer needed to contain the serialized version of the packet
+  */
+int MQTTSNSerialize_disconnectLength(int duration)
+{
+	int len = 0;
+
+	FUNC_ENTRY;
+	len = (duration >= 0) ? 3 : 1;
+	FUNC_EXIT_RC(len);
+	return len;
+}
+
+
+/**
+  * Serializes a disconnect packet into the supplied buffer, ready for writing to a socket
+  * @param buf the buffer into which the packet will be serialized
+  * @param buflen the length in bytes of the supplied buffer, to avoid overruns
+  * @param duration optional duration, not added to packet if < 0
+  * @return serialized length, or error if 0
+  */
+int MQTTSNSerialize_disconnect(unsigned char* buf, int buflen, int duration)
+{
+	int rc = -1;
+	unsigned char *ptr = buf;
+	int len = 0;
+
+	FUNC_ENTRY;
+	if ((len = MQTTSNPacket_len(MQTTSNSerialize_disconnectLength(duration))) > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len); /* write length */
+	writeChar(&ptr, MQTTSN_DISCONNECT);      /* write message type */
+
+	if (duration >= 0)
+		writeInt(&ptr, duration);
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}