Basic C library for MQTT packet serialization and deserialization
Dependents: MQTT MQTT MQTT MQTT ... more
Fork of MQTTPacket by
MQTTSerializePublish.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 * Ian Craggs - fix for https://bugs.eclipse.org/bugs/show_bug.cgi?id=453144 00016 *******************************************************************************/ 00017 00018 #include "MQTTPacket.h" 00019 #include "StackTrace.h" 00020 00021 #include <string.h> 00022 00023 00024 /** 00025 * Determines the length of the MQTT publish packet that would be produced using the supplied parameters 00026 * @param qos the MQTT QoS of the publish (packetid is omitted for QoS 0) 00027 * @param topicName the topic name to be used in the publish 00028 * @param payloadlen the length of the payload to be sent 00029 * @return the length of buffer needed to contain the serialized version of the packet 00030 */ 00031 int MQTTSerialize_publishLength(int qos, MQTTString topicName, int payloadlen) 00032 { 00033 int len = 0; 00034 00035 len += 2 + MQTTstrlen(topicName) + payloadlen; 00036 if (qos > 0) 00037 len += 2; /* packetid */ 00038 return len; 00039 } 00040 00041 00042 /** 00043 * Serializes the supplied publish data into the supplied buffer, ready for sending 00044 * @param buf the buffer into which the packet will be serialized 00045 * @param buflen the length in bytes of the supplied buffer 00046 * @param dup integer - the MQTT dup flag 00047 * @param qos integer - the MQTT QoS value 00048 * @param retained integer - the MQTT retained flag 00049 * @param packetid integer - the MQTT packet identifier 00050 * @param topicName MQTTString - the MQTT topic in the publish 00051 * @param payload byte buffer - the MQTT publish payload 00052 * @param payloadlen integer - the length of the MQTT payload 00053 * @return the length of the serialized data. <= 0 indicates error 00054 */ 00055 int MQTTSerialize_publish(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned char retained, unsigned short packetid, 00056 MQTTString topicName, unsigned char* payload, int payloadlen) 00057 { 00058 unsigned char *ptr = buf; 00059 MQTTHeader header = {0}; 00060 int rem_len = 0; 00061 int rc = 0; 00062 00063 FUNC_ENTRY; 00064 if (MQTTPacket_len(rem_len = MQTTSerialize_publishLength(qos, topicName, payloadlen)) > buflen) 00065 { 00066 rc = MQTTPACKET_BUFFER_TOO_SHORT; 00067 goto exit; 00068 } 00069 00070 header.bits.type = PUBLISH; 00071 header.bits.dup = dup; 00072 header.bits.qos = qos; 00073 header.bits.retain = retained; 00074 writeChar(&ptr, header.byte); /* write header */ 00075 00076 ptr += MQTTPacket_encode(ptr, rem_len); /* write remaining length */; 00077 00078 writeMQTTString(&ptr, topicName); 00079 00080 if (qos > 0) 00081 writeInt(&ptr, packetid); 00082 00083 memcpy(ptr, payload, payloadlen); 00084 ptr += payloadlen; 00085 00086 rc = ptr - buf; 00087 00088 exit: 00089 FUNC_EXIT_RC(rc); 00090 return rc; 00091 } 00092 00093 00094 00095 /** 00096 * Serializes the ack packet into the supplied buffer. 00097 * @param buf the buffer into which the packet will be serialized 00098 * @param buflen the length in bytes of the supplied buffer 00099 * @param type the MQTT packet type 00100 * @param dup the MQTT dup flag 00101 * @param packetid the MQTT packet identifier 00102 * @return serialized length, or error if 0 00103 */ 00104 int MQTTSerialize_ack(unsigned char* buf, int buflen, unsigned char packettype, unsigned char dup, unsigned short packetid) 00105 { 00106 MQTTHeader header = {0}; 00107 int rc = 0; 00108 unsigned char *ptr = buf; 00109 00110 FUNC_ENTRY; 00111 if (buflen < 4) 00112 { 00113 rc = MQTTPACKET_BUFFER_TOO_SHORT; 00114 goto exit; 00115 } 00116 header.bits.type = packettype; 00117 header.bits.dup = dup; 00118 header.bits.qos = (packettype == PUBREL) ? 1 : 0; 00119 writeChar(&ptr, header.byte); /* write header */ 00120 00121 ptr += MQTTPacket_encode(ptr, 2); /* write remaining length */ 00122 writeInt(&ptr, packetid); 00123 rc = ptr - buf; 00124 exit: 00125 FUNC_EXIT_RC(rc); 00126 return rc; 00127 } 00128 00129 00130 /** 00131 * Serializes a puback packet into the supplied buffer. 00132 * @param buf the buffer into which the packet will be serialized 00133 * @param buflen the length in bytes of the supplied buffer 00134 * @param packetid integer - the MQTT packet identifier 00135 * @return serialized length, or error if 0 00136 */ 00137 int MQTTSerialize_puback(unsigned char* buf, int buflen, unsigned short packetid) 00138 { 00139 return MQTTSerialize_ack(buf, buflen, PUBACK, 0, packetid); 00140 } 00141 00142 00143 /** 00144 * Serializes a pubrel packet into the supplied buffer. 00145 * @param buf the buffer into which the packet will be serialized 00146 * @param buflen the length in bytes of the supplied buffer 00147 * @param dup integer - the MQTT dup flag 00148 * @param packetid integer - the MQTT packet identifier 00149 * @return serialized length, or error if 0 00150 */ 00151 int MQTTSerialize_pubrel(unsigned char* buf, int buflen, unsigned char dup, unsigned short packetid) 00152 { 00153 return MQTTSerialize_ack(buf, buflen, PUBREL, dup, packetid); 00154 } 00155 00156 00157 /** 00158 * Serializes a pubrel packet into the supplied buffer. 00159 * @param buf the buffer into which the packet will be serialized 00160 * @param buflen the length in bytes of the supplied buffer 00161 * @param packetid integer - the MQTT packet identifier 00162 * @return serialized length, or error if 0 00163 */ 00164 int MQTTSerialize_pubcomp(unsigned char* buf, int buflen, unsigned short packetid) 00165 { 00166 return MQTTSerialize_ack(buf, buflen, PUBCOMP, 0, packetid); 00167 } 00168
Generated on Tue Jul 12 2022 17:50:32 by 1.7.2