1 /*******************************************************************************
2 * Copyright (c) 2014 IBM Corp.
3 *
4 * All rights reserved. This program and the accompanying materials
5 * are made available under the terms of the Eclipse Public License v1.0
6 * and Eclipse Distribution License v1.0 which accompany this distribution.
7 *
8 * The Eclipse Public License is available at
9 * http://www.eclipse.org/legal/epl-v10.html
10 * and the Eclipse Distribution License is available at
11 * http://www.eclipse.org/org/documents/edl-v10.php.
12 *
13 * Contributors:
14 * Ian Craggs - initial API and implementation and/or initial documentation
15 * Ian Craggs - fix for https://bugs.eclipse.org/bugs/show_bug.cgi?id=453144
16 *******************************************************************************/
17
18 #include "MQTTPacket.h"
19
20 #include <string.h>
21
22
23 /**
24 * Determines the length of the MQTT publish packet that would be produced using
25 * the supplied parameters
26 * @param qos the MQTT QoS of the publish (packetid is omitted for QoS 0)
27 * @param topicName the topic name to be used in the publish
28 * @param payloadlen the length of the payload to be sent
29 * @return the length of buffer needed to contain the serialized version of the
30 * packet
31 */
MQTTSerialize_publishLength(int qos,MQTTString topicName,int payloadlen)32 int MQTTSerialize_publishLength(int qos, MQTTString topicName, int payloadlen)
33 {
34 int len = 0;
35
36 len += 2 + MQTTstrlen(topicName) + payloadlen;
37 if (qos > 0) {
38 len += 2; /* packetid */
39 }
40 return len;
41 }
42
43 /**
44 * Serializes the supplied publish data into the supplied buffer, ready for
45 * sending
46 * @param buf the buffer into which the packet will be serialized
47 * @param buflen the length in bytes of the supplied buffer
48 * @param dup integer - the MQTT dup flag
49 * @param qos integer - the MQTT QoS value
50 * @param retained integer - the MQTT retained flag
51 * @param packetid integer - the MQTT packet identifier
52 * @param topicName MQTTString - the MQTT topic in the publish
53 * @param payload byte buffer - the MQTT publish payload
54 * @param payloadlen integer - the length of the MQTT payload
55 * @return the length of the serialized data. <= 0 indicates error
56 */
MQTTSerialize_publish(unsigned char * buf,int buflen,unsigned char dup,int qos,unsigned char retained,unsigned short packetid,MQTTString topicName,unsigned char * payload,int payloadlen)57 int MQTTSerialize_publish(unsigned char *buf, int buflen, unsigned char dup,
58 int qos, unsigned char retained,
59 unsigned short packetid, MQTTString topicName,
60 unsigned char *payload, int payloadlen)
61 {
62 unsigned char *ptr = buf;
63 MQTTHeader header = { 0 };
64 int rem_len = 0;
65 int rc = 0;
66
67 rem_len = MQTTSerialize_publishLength(qos, topicName, payloadlen);
68 if (MQTTPacket_len(rem_len) > buflen) {
69 rc = MQTTPACKET_BUFFER_TOO_SHORT;
70 goto exit;
71 }
72
73 MQTT_HEADER_SET_TYPE(header.byte, PUBLISH);
74 MQTT_HEADER_SET_DUP(header.byte, dup);
75 MQTT_HEADER_SET_QOS(header.byte, qos);
76 MQTT_HEADER_SET_RETAIN(header.byte, retained);
77 writeChar(&ptr, header.byte); /* write header */
78
79 ptr += MQTTPacket_encode(ptr, rem_len); /* write remaining length */
80 ;
81
82 writeMQTTString(&ptr, topicName);
83
84 if (qos > 0) {
85 writeInt(&ptr, packetid);
86 }
87
88 memcpy(ptr, payload, payloadlen);
89 ptr += payloadlen;
90
91 rc = ptr - buf;
92
93 exit:
94 return rc;
95 }
96
97 /**
98 * Serializes the ack packet into the supplied buffer.
99 * @param buf the buffer into which the packet will be serialized
100 * @param buflen the length in bytes of the supplied buffer
101 * @param type the MQTT packet type
102 * @param dup the MQTT dup flag
103 * @param packetid the MQTT packet identifier
104 * @return serialized length, or error if 0
105 */
MQTTSerialize_ack(unsigned char * buf,int buflen,unsigned char packettype,unsigned char dup,unsigned short packetid)106 int MQTTSerialize_ack(unsigned char *buf, int buflen, unsigned char packettype,
107 unsigned char dup, unsigned short packetid)
108 {
109 MQTTHeader header = { 0 };
110 int rc = 0;
111 unsigned char *ptr = buf;
112
113 if (buflen < 4) {
114 rc = MQTTPACKET_BUFFER_TOO_SHORT;
115 goto exit;
116 }
117 MQTT_HEADER_SET_TYPE(header.byte, packettype);
118 MQTT_HEADER_SET_DUP(header.byte, dup);
119 MQTT_HEADER_SET_QOS(header.byte, ((packettype == PUBREL) ? 1 : 0));
120 writeChar(&ptr, header.byte); /* write header */
121
122 ptr += MQTTPacket_encode(ptr, 2); /* write remaining length */
123 writeInt(&ptr, packetid);
124 rc = ptr - buf;
125 exit:
126 return rc;
127 }
128
129 /**
130 * Serializes a puback packet into the supplied buffer.
131 * @param buf the buffer into which the packet will be serialized
132 * @param buflen the length in bytes of the supplied buffer
133 * @param packetid integer - the MQTT packet identifier
134 * @return serialized length, or error if 0
135 */
136 /* int MQTTSerialize_puback(unsigned char* buf, int buflen, unsigned short
137 * packetid) */
138 /* { */
139 /* return MQTTSerialize_ack(buf, buflen, PUBACK, 0, packetid); */
140 /* } */
141
142 #if WITH_MQTT_QOS2_PACKET
143 /**
144 * Serializes a pubrel packet into the supplied buffer.
145 * @param buf the buffer into which the packet will be serialized
146 * @param buflen the length in bytes of the supplied buffer
147 * @param dup integer - the MQTT dup flag
148 * @param packetid integer - the MQTT packet identifier
149 * @return serialized length, or error if 0
150 */
MQTTSerialize_pubrel(unsigned char * buf,int buflen,unsigned char dup,unsigned short packetid)151 int MQTTSerialize_pubrel(unsigned char *buf, int buflen, unsigned char dup,
152 unsigned short packetid)
153 {
154 return MQTTSerialize_ack(buf, buflen, PUBREL, dup, packetid);
155 }
156
157 /**
158 * Serializes a pubrel packet into the supplied buffer.
159 * @param buf the buffer into which the packet will be serialized
160 * @param buflen the length in bytes of the supplied buffer
161 * @param packetid integer - the MQTT packet identifier
162 * @return serialized length, or error if 0
163 */
MQTTSerialize_pubcomp(unsigned char * buf,int buflen,unsigned short packetid)164 int MQTTSerialize_pubcomp(unsigned char *buf, int buflen,
165 unsigned short packetid)
166 {
167 return MQTTSerialize_ack(buf, buflen, PUBCOMP, 0, packetid);
168 }
169 #endif /* #if WITH_MQTT_QOS2_PACKET */
170