Diff: MQTT/MQTTPacket/MQTTConnectServer.c

Revision:

0:0a2f634d3324

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MQTT/MQTTPacket/MQTTConnectServer.c	Thu Feb 09 07:26:57 2017 +0000
@@ -0,0 +1,148 @@
+/*******************************************************************************
+ * 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 "StackTrace.h"
+#include "MQTTPacket.h"
+#include <string.h>
+
+#define min(a, b) ((a < b) ? a : b)
+
+
+/**
+  * Validates MQTT protocol name and version combinations
+  * @param protocol the MQTT protocol name as an MQTTString
+  * @param version the MQTT protocol version number, as in the connect packet
+  * @return correct MQTT combination?  1 is true, 0 is false
+  */
+int MQTTPacket_checkVersion(MQTTString* protocol, int version)
+{
+	int rc = 0;
+
+	if (version == 3 && memcmp(protocol->lenstring.data, "MQIdsp",
+			min(6, protocol->lenstring.len)) == 0)
+		rc = 1;
+	else if (version == 4 && memcmp(protocol->lenstring.data, "MQTT",
+			min(4, protocol->lenstring.len)) == 0)
+		rc = 1;
+	return rc;
+}
+
+
+/**
+  * Deserializes the supplied (wire) buffer into connect data structure
+  * @param data the connect data structure to be filled out
+  * @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 MQTTDeserialize_connect(MQTTPacket_connectData* data, unsigned char* buf, int len)
+{
+	MQTTHeader header = {0};
+	MQTTConnectFlags flags = {0};
+	unsigned char* curdata = buf;
+	unsigned char* enddata = &buf[len];
+	int rc = 0;
+	MQTTString Protocol;
+	int version;
+	int mylen = 0;
+
+	FUNC_ENTRY;
+	header.byte = readChar(&curdata);
+	if (header.bits.type != CONNECT)
+		goto exit;
+
+	curdata += MQTTPacket_decodeBuf(curdata, &mylen); /* read remaining length */
+
+	if (!readMQTTLenString(&Protocol, &curdata, enddata) ||
+		enddata - curdata < 0) /* do we have enough data to read the protocol version byte? */
+		goto exit;
+
+	version = (int)readChar(&curdata); /* Protocol version */
+	/* If we don't recognize the protocol version, we don't parse the connect packet on the
+	 * basis that we don't know what the format will be.
+	 */
+	if (MQTTPacket_checkVersion(&Protocol, version))
+	{
+		flags.all = readChar(&curdata);
+		data->cleansession = flags.bits.cleansession;
+		data->keepAliveInterval = readInt(&curdata);
+		if (!readMQTTLenString(&data->clientID, &curdata, enddata))
+			goto exit;
+		if (flags.bits.will)
+		{
+			data->willFlag = 1;
+			data->will.qos = flags.bits.willQoS;
+			data->will.retained = flags.bits.willRetain;
+			if (!readMQTTLenString(&data->will.topicName, &curdata, enddata) ||
+				  !readMQTTLenString(&data->will.message, &curdata, enddata))
+				goto exit;
+		}
+		if (flags.bits.username)
+		{
+			if (enddata - curdata < 3 || !readMQTTLenString(&data->username, &curdata, enddata))
+				goto exit; /* username flag set, but no username supplied - invalid */
+			if (flags.bits.password &&
+				(enddata - curdata < 3 || !readMQTTLenString(&data->password, &curdata, enddata)))
+				goto exit; /* password flag set, but no password supplied - invalid */
+		}
+		else if (flags.bits.password)
+			goto exit; /* password flag set without username - invalid */
+		rc = 1;
+	}
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+/**
+  * Serializes the connack packet into the supplied buffer.
+  * @param buf the buffer into which the packet will be serialized
+  * @param buflen the length in bytes of the supplied buffer
+  * @param connack_rc the integer connack return code to be used 
+  * @param sessionPresent the MQTT 3.1.1 sessionPresent flag
+  * @return serialized length, or error if 0
+  */
+int MQTTSerialize_connack(unsigned char* buf, int buflen, unsigned char connack_rc, unsigned char sessionPresent)
+{
+	MQTTHeader header = {0};
+	int rc = 0;
+	unsigned char *ptr = buf;
+	MQTTConnackFlags flags = {0};
+
+	FUNC_ENTRY;
+	if (buflen < 2)
+	{
+		rc = MQTTPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	header.byte = 0;
+	header.bits.type = CONNACK;
+	writeChar(&ptr, header.byte); /* write header */
+
+	ptr += MQTTPacket_encode(ptr, 2); /* write remaining length */
+
+	flags.all = 0;
+	flags.bits.sessionpresent = sessionPresent;
+	writeChar(&ptr, flags.all); 
+	writeChar(&ptr, connack_rc);
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+