MQTT / MQTTPacket

Basic C library for MQTT packet serialization and deserialization

Dependents:   MQTT MQTT MQTT MQTT ... more

Fork of MQTTPacket by MQTT

This library is part of the EclipseTM Paho project; specifically the embedded client.

A basic MQTT library in C for packet serialization and deserialization

MQTTConnectServer.c@1:069ae45b7070, 2014-03-31 (annotated)

Committer:
icraggs
Date:
Mon Mar 31 15:48:23 2014 +0000
Revision:
1:069ae45b7070
Parent:
0:7734401cc1b4
Child:
9:3893bc7343f4
Child:
12:cd99ac9cb25a
Two small corrections

Who changed what in which revision?

UserRevisionLine numberNew contents of line
icraggs 0:7734401cc1b4 1 /*******************************************************************************
icraggs 0:7734401cc1b4 2 * Copyright (c) 2014 IBM Corp.
icraggs 0:7734401cc1b4 3 *
icraggs 0:7734401cc1b4 4 * All rights reserved. This program and the accompanying materials
icraggs 0:7734401cc1b4 5 * are made available under the terms of the Eclipse Public License v1.0
icraggs 0:7734401cc1b4 6 * and Eclipse Distribution License v1.0 which accompany this distribution.
icraggs 0:7734401cc1b4 7 *
icraggs 0:7734401cc1b4 8 * The Eclipse Public License is available at
icraggs 0:7734401cc1b4 9 * http://www.eclipse.org/legal/epl-v10.html
icraggs 0:7734401cc1b4 10 * and the Eclipse Distribution License is available at
icraggs 0:7734401cc1b4 11 * http://www.eclipse.org/org/documents/edl-v10.php.
icraggs 0:7734401cc1b4 12 *
icraggs 0:7734401cc1b4 13 * Contributors:
icraggs 0:7734401cc1b4 14 * Ian Craggs - initial API and implementation and/or initial documentation
icraggs 0:7734401cc1b4 15 *******************************************************************************/
icraggs 0:7734401cc1b4 16
icraggs 0:7734401cc1b4 17 #include "StackTrace.h"
icraggs 0:7734401cc1b4 18 #include "MQTTPacket.h"
icraggs 0:7734401cc1b4 19 #include <string.h>
icraggs 0:7734401cc1b4 20
icraggs 0:7734401cc1b4 21 #define min(a, b) ((a < b) ? 1 : 0)
icraggs 0:7734401cc1b4 22
icraggs 0:7734401cc1b4 23
icraggs 0:7734401cc1b4 24 /**
icraggs 0:7734401cc1b4 25 * Validates MQTT protocol name and version combinations
icraggs 0:7734401cc1b4 26 * @param protocol the MQTT protocol name as an MQTTString
icraggs 0:7734401cc1b4 27 * @param version the MQTT protocol version number, as in the connect packet
icraggs 0:7734401cc1b4 28 * @return correct MQTT combination? 1 is true, 0 is false
icraggs 0:7734401cc1b4 29 */
icraggs 0:7734401cc1b4 30 int MQTTPacket_checkVersion(MQTTString* protocol, int version)
icraggs 0:7734401cc1b4 31 {
icraggs 0:7734401cc1b4 32 int rc = 0;
icraggs 0:7734401cc1b4 33
icraggs 0:7734401cc1b4 34 if (version == 3 && memcmp(protocol->lenstring.data, "MQIdsp",
icraggs 0:7734401cc1b4 35 min(6, protocol->lenstring.len)))
icraggs 0:7734401cc1b4 36 rc = 1;
icraggs 0:7734401cc1b4 37 else if (version == 3 && memcmp(protocol->lenstring.data, "MQTT",
icraggs 0:7734401cc1b4 38 min(4, protocol->lenstring.len)))
icraggs 0:7734401cc1b4 39 rc = 1;
icraggs 0:7734401cc1b4 40
icraggs 1:069ae45b7070 41 return rc;
icraggs 0:7734401cc1b4 42 }
icraggs 0:7734401cc1b4 43
icraggs 0:7734401cc1b4 44
icraggs 0:7734401cc1b4 45 /**
icraggs 0:7734401cc1b4 46 * Deserializes the supplied (wire) buffer into connect data structure
icraggs 0:7734401cc1b4 47 * @param data the connect data structure to be filled out
icraggs 0:7734401cc1b4 48 * @param buf the raw buffer data, of the correct length determined by the remaining length field
icraggs 0:7734401cc1b4 49 * @param len the length in bytes of the data in the supplied buffer
icraggs 0:7734401cc1b4 50 * @return error code. 1 is success, 0 is failure
icraggs 0:7734401cc1b4 51 */
icraggs 0:7734401cc1b4 52 int MQTTDeserialize_connect(MQTTPacket_connectData* data, char* buf, int len)
icraggs 0:7734401cc1b4 53 {
icraggs 0:7734401cc1b4 54 MQTTHeader header;
icraggs 0:7734401cc1b4 55 MQTTConnectFlags flags;
icraggs 0:7734401cc1b4 56 char* curdata = buf;
icraggs 0:7734401cc1b4 57 char* enddata = &buf[len];
icraggs 0:7734401cc1b4 58 int rc = 0;
icraggs 0:7734401cc1b4 59 MQTTString Protocol;
icraggs 0:7734401cc1b4 60 int version;
icraggs 0:7734401cc1b4 61 int mylen = 0;
icraggs 0:7734401cc1b4 62
icraggs 0:7734401cc1b4 63 FUNC_ENTRY;
icraggs 0:7734401cc1b4 64 header.byte = readChar(&curdata);
icraggs 0:7734401cc1b4 65
icraggs 0:7734401cc1b4 66 curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
icraggs 0:7734401cc1b4 67
icraggs 0:7734401cc1b4 68 if (!readMQTTLenString(&Protocol, &curdata, enddata) ||
icraggs 0:7734401cc1b4 69 enddata - curdata < 0) /* do we have enough data to read the protocol version byte? */
icraggs 0:7734401cc1b4 70 goto exit;
icraggs 0:7734401cc1b4 71
icraggs 0:7734401cc1b4 72 version = (int)readChar(&curdata); /* Protocol version */
icraggs 0:7734401cc1b4 73 /* If we don't recognize the protocol version, we don't parse the connect packet on the
icraggs 0:7734401cc1b4 74 * basis that we don't know what the format will be.
icraggs 0:7734401cc1b4 75 */
icraggs 0:7734401cc1b4 76 if (MQTTPacket_checkVersion(&Protocol, version))
icraggs 0:7734401cc1b4 77 {
icraggs 0:7734401cc1b4 78 flags.all = readChar(&curdata);
icraggs 0:7734401cc1b4 79 data->cleansession = flags.bits.cleansession;
icraggs 0:7734401cc1b4 80 data->keepAliveInterval = readInt(&curdata);
icraggs 0:7734401cc1b4 81 if (!readMQTTLenString(&data->clientID, &curdata, enddata))
icraggs 0:7734401cc1b4 82 goto exit;
icraggs 0:7734401cc1b4 83 if (flags.bits.will)
icraggs 0:7734401cc1b4 84 {
icraggs 0:7734401cc1b4 85 data->willFlag = 1;
icraggs 0:7734401cc1b4 86 data->will.qos = flags.bits.willQoS;
icraggs 0:7734401cc1b4 87 data->will.retained = flags.bits.willRetain;
icraggs 0:7734401cc1b4 88 if (!readMQTTLenString(&data->will.topicName, &curdata, enddata) ||
icraggs 0:7734401cc1b4 89 !readMQTTLenString(&data->will.message, &curdata, enddata))
icraggs 0:7734401cc1b4 90 goto exit;
icraggs 0:7734401cc1b4 91 }
icraggs 0:7734401cc1b4 92 if (flags.bits.username)
icraggs 0:7734401cc1b4 93 {
icraggs 0:7734401cc1b4 94 if (enddata - curdata < 3 || !readMQTTLenString(&data->username, &curdata, enddata))
icraggs 0:7734401cc1b4 95 goto exit; /* username flag set, but no username supplied - invalid */
icraggs 0:7734401cc1b4 96 if (flags.bits.password &&
icraggs 0:7734401cc1b4 97 (enddata - curdata < 3 || !readMQTTLenString(&data->password, &curdata, enddata)))
icraggs 0:7734401cc1b4 98 goto exit; /* password flag set, but no password supplied - invalid */
icraggs 0:7734401cc1b4 99 }
icraggs 0:7734401cc1b4 100 else if (flags.bits.password)
icraggs 0:7734401cc1b4 101 goto exit; /* password flag set without username - invalid */
icraggs 0:7734401cc1b4 102 rc = 1;
icraggs 0:7734401cc1b4 103 }
icraggs 0:7734401cc1b4 104 exit:
icraggs 0:7734401cc1b4 105 FUNC_EXIT_RC(rc);
icraggs 0:7734401cc1b4 106 return rc;
icraggs 0:7734401cc1b4 107 }
icraggs 0:7734401cc1b4 108
icraggs 0:7734401cc1b4 109
icraggs 0:7734401cc1b4 110 /**
icraggs 0:7734401cc1b4 111 * Serializes the connack packet into the supplied buffer.
icraggs 0:7734401cc1b4 112 * @param buf the buffer into which the packet will be serialized
icraggs 0:7734401cc1b4 113 * @param buflen the length in bytes of the supplied buffer
icraggs 0:7734401cc1b4 114 * @param connack_rc the integer connack return code to be used
icraggs 0:7734401cc1b4 115 * @return serialized length, or error if 0
icraggs 0:7734401cc1b4 116 */
icraggs 0:7734401cc1b4 117 int MQTTSerialize_connack(char* buf, int buflen, int connack_rc)
icraggs 0:7734401cc1b4 118 {
icraggs 0:7734401cc1b4 119 MQTTHeader header;
icraggs 0:7734401cc1b4 120 int rc = 0;
icraggs 0:7734401cc1b4 121 char *ptr = buf;
icraggs 0:7734401cc1b4 122
icraggs 0:7734401cc1b4 123 FUNC_ENTRY;
icraggs 0:7734401cc1b4 124 if (buflen < 2)
icraggs 0:7734401cc1b4 125 {
icraggs 0:7734401cc1b4 126 rc = MQTTPACKET_BUFFER_TOO_SHORT;
icraggs 0:7734401cc1b4 127 goto exit;
icraggs 0:7734401cc1b4 128 }
icraggs 0:7734401cc1b4 129 header.byte = 0;
icraggs 0:7734401cc1b4 130 header.bits.type = CONNACK;
icraggs 0:7734401cc1b4 131 writeChar(&ptr, header.byte); /* write header */
icraggs 0:7734401cc1b4 132
icraggs 0:7734401cc1b4 133 ptr += MQTTPacket_encode(ptr, 2); /* write remaining length */
icraggs 0:7734401cc1b4 134
icraggs 0:7734401cc1b4 135 writeChar(&ptr, 0); /* compression byte - not used */
icraggs 0:7734401cc1b4 136 writeChar(&ptr, connack_rc);
icraggs 0:7734401cc1b4 137
icraggs 0:7734401cc1b4 138 rc = ptr - buf;
icraggs 0:7734401cc1b4 139 exit:
icraggs 0:7734401cc1b4 140 FUNC_EXIT_RC(rc);
icraggs 0:7734401cc1b4 141 return rc;
icraggs 0:7734401cc1b4 142 }
icraggs 0:7734401cc1b4 143