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 *******************************************************************************/
16
17 #include "MQTTPacket.h"
18 #include "StackTrace.h"
19
20 #include <string.h>
21
22 /**
23 * Determines the length of the MQTT subscribe packet that would be produced using the supplied parameters
24 * @param count the number of topic filter strings in topicFilters
25 * @param topicFilters the array of topic filter strings to be used in the publish
26 * @return the length of buffer needed to contain the serialized version of the packet
27 */
MQTTSerialize_subscribeLength(int count,MQTTString topicFilters[])28 int MQTTSerialize_subscribeLength(int count, MQTTString topicFilters[])
29 {
30 int i;
31 int len = 2; /* packetid */
32
33 for (i = 0; i < count; ++i)
34 len += 2 + MQTTstrlen(topicFilters[i]) + 1; /* length + topic + req_qos */
35 return len;
36 }
37
38
39 /**
40 * Serializes the supplied subscribe data into the supplied buffer, ready for sending
41 * @param buf the buffer into which the packet will be serialized
42 * @param buflen the length in bytes of the supplied bufferr
43 * @param dup integer - the MQTT dup flag
44 * @param packetid integer - the MQTT packet identifier
45 * @param count - number of members in the topicFilters and reqQos arrays
46 * @param topicFilters - array of topic filter names
47 * @param requestedQoSs - array of requested QoS
48 * @return the length of the serialized data. <= 0 indicates error
49 */
MQTTSerialize_subscribe(unsigned char * buf,int buflen,unsigned char dup,unsigned short packetid,int count,MQTTString topicFilters[],int requestedQoSs[])50 int MQTTSerialize_subscribe(unsigned char* buf, int buflen, unsigned char dup, unsigned short packetid, int count,
51 MQTTString topicFilters[], int requestedQoSs[])
52 {
53 unsigned char *ptr = buf;
54 MQTTHeader header = {0};
55 int rem_len = 0;
56 int rc = 0;
57 int i = 0;
58
59 FUNC_ENTRY;
60 if (MQTTPacket_len(rem_len = MQTTSerialize_subscribeLength(count, topicFilters)) > buflen)
61 {
62 rc = MQTTPACKET_BUFFER_TOO_SHORT;
63 goto exit;
64 }
65
66 header.byte = 0;
67 header.bits.type = SUBSCRIBE;
68 header.bits.dup = dup;
69 header.bits.qos = 1;
70 writeChar(&ptr, header.byte); /* write header */
71
72 ptr += MQTTPacket_encode(ptr, rem_len); /* write remaining length */;
73
74 writeInt(&ptr, packetid);
75
76 for (i = 0; i < count; ++i)
77 {
78 writeMQTTString(&ptr, topicFilters[i]);
79 writeChar(&ptr, requestedQoSs[i]);
80 }
81
82 rc = ptr - buf;
83 exit:
84 FUNC_EXIT_RC(rc);
85 return rc;
86 }
87
88
89
90 /**
91 * Deserializes the supplied (wire) buffer into suback data
92 * @param packetid returned integer - the MQTT packet identifier
93 * @param maxcount - the maximum number of members allowed in the grantedQoSs array
94 * @param count returned integer - number of members in the grantedQoSs array
95 * @param grantedQoSs returned array of integers - the granted qualities of service
96 * @param buf the raw buffer data, of the correct length determined by the remaining length field
97 * @param buflen the length in bytes of the data in the supplied buffer
98 * @return error code. 1 is success, 0 is failure
99 */
MQTTDeserialize_suback(unsigned short * packetid,int maxcount,int * count,int grantedQoSs[],unsigned char * buf,int buflen)100 int MQTTDeserialize_suback(unsigned short* packetid, int maxcount, int* count, int grantedQoSs[], unsigned char* buf, int buflen)
101 {
102 MQTTHeader header = {0};
103 unsigned char* curdata = buf;
104 unsigned char* enddata = NULL;
105 int rc = 0;
106 int mylen;
107
108 FUNC_ENTRY;
109 header.byte = readChar(&curdata);
110 if (header.bits.type != SUBACK)
111 goto exit;
112
113 curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
114 enddata = curdata + mylen;
115 if (enddata - curdata < 2)
116 goto exit;
117
118 *packetid = readInt(&curdata);
119
120 *count = 0;
121 while (curdata < enddata)
122 {
123 if (*count > maxcount)
124 {
125 rc = -1;
126 goto exit;
127 }
128 grantedQoSs[(*count)++] = readChar(&curdata);
129 }
130
131 rc = 1;
132 exit:
133 FUNC_EXIT_RC(rc);
134 return rc;
135 }
136
137
138