MQTTSNSubscribeServer.c

00001 /*******************************************************************************
00002  * Copyright (c) 2014 IBM Corp.
00003  *
00004  * All rights reserved. This program and the accompanying materials
00005  * are made available under the terms of the Eclipse Public License v1.0
00006  * and Eclipse Distribution License v1.0 which accompany this distribution.
00007  *
00008  * The Eclipse Public License is available at
00009  *    http://www.eclipse.org/legal/epl-v10.html
00010  * and the Eclipse Distribution License is available at
00011  *   http://www.eclipse.org/org/documents/edl-v10.php.
00012  *
00013  * Contributors:
00014  *    Ian Craggs - initial API and implementation and/or initial documentation
00015  *******************************************************************************/
00016 
00017 #include "StackTrace.h"
00018 #include "MQTTSNPacket.h"
00019 #include <string.h>
00020 
00021 
00022 /**
00023   * Deserializes the supplied (wire) buffer into subscribe data
00024   * @param dup the returned MQTT-SN dup flag
00025   * @param qos the returned qos
00026   * @param packetid returned - the same value as the one contained in the corresponding SUBSCRIBE
00027   * @param topicFilter returned - the topic filter - normal, predefined or short
00028   * @param buf the raw buffer data, of the correct length determined by the remaining length field
00029   * @param buflen the length in bytes of the data in the supplied buffer
00030   * @return error code.  1 is success
00031   */
00032 int MQTTSNDeserialize_subscribe(unsigned char* dup, int* qos, unsigned short* packetid,
00033         MQTTSN_topicid* topicFilter, unsigned char* buf, int buflen)
00034 {
00035     MQTTSNFlags flags = {0};
00036     unsigned char* curdata = buf;
00037     unsigned char* enddata = NULL;
00038     int rc = 0;
00039     int mylen = 0;
00040 
00041     FUNC_ENTRY;
00042     curdata += (rc = MQTTSNPacket_decode(curdata, buflen, &mylen)); /* read length */
00043     enddata = buf + mylen;
00044     if (enddata - curdata > buflen)
00045         goto exit;
00046 
00047     if (MQTTSNPacket_readChar(&curdata) != MQTTSN_SUBSCRIBE)
00048         goto exit;
00049 
00050     flags.all = MQTTSNPacket_readChar(&curdata);
00051     *dup = flags.bits.dup;
00052     *qos = flags.bits.QoS;
00053 
00054     *packetid = MQTTSNPacket_readInt(&curdata);
00055 
00056     topicFilter->type = flags.bits.topicIdType;
00057 
00058     if (topicFilter->type == MQTTSN_TOPIC_TYPE_NORMAL)
00059     {
00060         topicFilter->data.long_.len = enddata - curdata;
00061         topicFilter->data.long_.name = (char*)curdata;
00062     }
00063     else if (topicFilter->type == MQTTSN_TOPIC_TYPE_PREDEFINED)
00064         topicFilter->data.id = MQTTSNPacket_readInt(&curdata);
00065     else if (topicFilter->type == MQTTSN_TOPIC_TYPE_SHORT)
00066     {
00067         topicFilter->data.short_name[0] = MQTTSNPacket_readChar(&curdata);
00068         topicFilter->data.short_name[1] = MQTTSNPacket_readChar(&curdata);
00069     }
00070 
00071     rc = 1;
00072 exit:
00073     FUNC_EXIT_RC(rc);
00074     return rc;
00075 }
00076 
00077 
00078 /**
00079   * Serializes the supplied suback data into the supplied buffer, ready for sending
00080   * @param buf the buffer into which the packet will be serialized
00081   * @param buflen the length in bytes of the supplied buffer
00082   * @param qos integer - the MQTT-SN QoS value
00083   * @param topicid if "accepted" the value which will be used by the gateway in subsequent PUBLISH packets
00084   * @param packetid integer - the MQTT-SN packet identifier
00085   * @param returncode returned - "accepted" or rejection reason
00086   * @return the length of the serialized data.  <= 0 indicates error
00087   */
00088 int MQTTSNSerialize_suback(unsigned char* buf, int buflen, int qos, unsigned short topicid, unsigned short packetid,
00089         unsigned char returncode)
00090 {
00091     MQTTSNFlags flags = {0};
00092     unsigned char *ptr = buf;
00093     int len = 0;
00094     int rc = 0;
00095 
00096     FUNC_ENTRY;
00097     if ((len = MQTTSNPacket_len(7)) > buflen)
00098     {
00099         rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
00100         goto exit;
00101     }
00102     ptr += MQTTSNPacket_encode(ptr, len); /* write length */
00103     MQTTSNPacket_writeChar(&ptr, MQTTSN_SUBACK);      /* write message type */
00104 
00105     flags.all = 0;
00106     flags.bits.QoS = qos;
00107     MQTTSNPacket_writeChar(&ptr, flags.all);
00108 
00109     MQTTSNPacket_writeInt(&ptr, topicid);
00110     MQTTSNPacket_writeInt(&ptr, packetid);
00111     MQTTSNPacket_writeChar(&ptr, returncode);
00112 
00113     rc = ptr - buf;
00114 exit:
00115     FUNC_EXIT_RC(rc);
00116     return rc;
00117 }
00118 
00119 
00120