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* 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, "MQIsdp",
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;
data->willFlag = flags.bits.will;
if (flags.bits.will)
{
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;
}
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