123
MQTTSNSubscribeClient.c
- Committer:
- m_ahsan
- Date:
- 2019-01-03
- Revision:
- 2:573d544b5d3c
- Parent:
- 1:7fa362fa563f
File content as of revision 2:573d544b5d3c:
/******************************************************************************* * 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 MQTTSN subscribe packet that would be produced using the supplied parameters, * excluding length * @param topicName the topic name to be used in the publish * @return the length of buffer needed to contain the serialized version of the packet */ int MQTTSNSerialize_subscribeLength(MQTTSN_topicid* topicFilter) { int len = 4; if (topicFilter->type == MQTTSN_TOPIC_TYPE_NORMAL) len += topicFilter->data.long_.len; else if (topicFilter->type == MQTTSN_TOPIC_TYPE_SHORT || topicFilter->type == MQTTSN_TOPIC_TYPE_PREDEFINED) len += 2; return len; } /** * Serializes the supplied subscribe data into the supplied buffer, ready for sending * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param dup integer - the MQTT-SN dup flag * @param qos integer - the MQTT-SN QoS value * @param packetid integer - the MQTT-SN packet identifier * @param topic MQTTSN_topicid - the MQTT-SN topic in the subscribe * @return the length of the serialized data. <= 0 indicates error */ int MQTTSNSerialize_subscribe(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned short packetid, MQTTSN_topicid* topicFilter) { unsigned char *ptr = buf; MQTTSNFlags flags; int len = 0; int rc = 0; FUNC_ENTRY; if ((len = MQTTSNPacket_len(MQTTSNSerialize_subscribeLength(topicFilter))) > buflen) { rc = MQTTSNPACKET_BUFFER_TOO_SHORT; goto exit; } ptr += MQTTSNPacket_encode(ptr, len); /* write length */ MQTTSNPacket_writeChar(&ptr, MQTTSN_SUBSCRIBE); /* write message type */ flags.all = 0; flags.bits.dup = dup; flags.bits.QoS = qos; flags.bits.topicIdType = topicFilter->type; MQTTSNPacket_writeChar(&ptr, flags.all); MQTTSNPacket_writeInt(&ptr, packetid); /* now the topic id or name */ if (topicFilter->type == MQTTSN_TOPIC_TYPE_NORMAL) /* means long topic name */ { memcpy(ptr, topicFilter->data.long_.name, topicFilter->data.long_.len); ptr += topicFilter->data.long_.len; } else if (topicFilter->type == MQTTSN_TOPIC_TYPE_PREDEFINED) MQTTSNPacket_writeInt(&ptr, topicFilter->data.id); else if (topicFilter->type == MQTTSN_TOPIC_TYPE_SHORT) { MQTTSNPacket_writeChar(&ptr, topicFilter->data.short_name[0]); MQTTSNPacket_writeChar(&ptr, topicFilter->data.short_name[1]); } rc = ptr - buf; exit: FUNC_EXIT_RC(rc); return rc; } /** * Deserializes the supplied (wire) buffer into suback data * @param qos the returned qos * @param topicid returned if "accepted" the value which will be used by the gateway in subsequent PUBLISH packets * @param packetid returned - the same value as the one contained in the corresponding SUBSCRIBE * @param returncode returned - "accepted" or rejection reason * @param buf the raw buffer data, of the correct length determined by the remaining length field * @param buflen the length in bytes of the data in the supplied buffer * @return error code. 1 is success */ int MQTTSNDeserialize_suback(int* qos, unsigned short* topicid, unsigned short* packetid, unsigned char* returncode, unsigned char* buf, int buflen) { MQTTSNFlags flags; unsigned char* curdata = buf; unsigned char* enddata = NULL; int rc = 0; int mylen = 0; FUNC_ENTRY; curdata += (rc = MQTTSNPacket_decode(curdata, buflen, &mylen)); /* read length */ enddata = buf + mylen; if (enddata - curdata > buflen) goto exit; if (MQTTSNPacket_readChar(&curdata) != MQTTSN_SUBACK) goto exit; flags.all = MQTTSNPacket_readChar(&curdata); *qos = flags.bits.QoS; *topicid = MQTTSNPacket_readInt(&curdata); *packetid = MQTTSNPacket_readInt(&curdata); *returncode = MQTTSNPacket_readChar(&curdata); rc = 1; exit: FUNC_EXIT_RC(rc); return rc; }