123
MQTTSNSerializePublish.c
- Committer:
- icraggs
- Date:
- 2016-01-06
- Revision:
- 1:7fa362fa563f
- Parent:
- 0:c524a894b5e8
- Child:
- 2:573d544b5d3c
File content as of revision 1:7fa362fa563f:
/******************************************************************************* * Copyright (c) 2014, 2016 IBM Corp. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * and Eclipse Distribution License v1.0 which accompany this distribution. * * The Eclipse Public License is available at * http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * http://www.eclipse.org/org/documents/edl-v10.php. * * Contributors: * Ian Craggs - initial API and implementation and/or initial documentation *******************************************************************************/ #include "MQTTSNPacket.h" #include "StackTrace.h" #include <string.h> /** * Determines the length of the MQTT publish packet that would be produced using the supplied parameters * @param qos the MQTT QoS of the publish (packetid is omitted for QoS 0) * @param topicName the topic name to be used in the publish * @param payloadlen the length of the payload to be sent * @return the length of buffer needed to contain the serialized version of the packet */ int MQTTSNSerialize_publishLength(int payloadlen, MQTTSN_topicid topic, int qos) { int len = 6; if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3) len += topic.data.long_.len; return payloadlen + len; } /** * Serializes the supplied publish data into the supplied buffer, ready for sending * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param dup integer - the MQTT dup flag * @param qos integer - the MQTT QoS value * @param retained integer - the MQTT retained flag * @param packetid integer - the MQTT packet identifier * @param topic MQTTSN_topicid - the MQTT topic in the publish * @param payload byte buffer - the MQTT publish payload * @param payloadlen integer - the length of the MQTT payload * @return the length of the serialized data. <= 0 indicates error */ int MQTTSNSerialize_publish(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned char retained, unsigned short packetid, MQTTSN_topicid topic, unsigned char* payload, int payloadlen) { unsigned char *ptr = buf; MQTTSNFlags flags; int len = 0; int rc = 0; FUNC_ENTRY; if ((len = MQTTSNPacket_len(MQTTSNSerialize_publishLength(payloadlen, topic, qos))) > buflen) { rc = MQTTSNPACKET_BUFFER_TOO_SHORT; goto exit; } ptr += MQTTSNPacket_encode(ptr, len); /* write length */ MQTTSNPacket_writeChar(&ptr, MQTTSN_PUBLISH); /* write message type */ flags.all = 0; flags.bits.dup = dup; flags.bits.QoS = qos; flags.bits.retain = retained; flags.bits.topicIdType = topic.type; MQTTSNPacket_writeChar(&ptr, flags.all); if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3) { /* special arrangement for long topic names in QoS -1 publishes. The length of the topic is in the topicid field */ MQTTSNPacket_writeInt(&ptr, topic.data.long_.len); /* topic length */ } else if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL || topic.type == MQTTSN_TOPIC_TYPE_PREDEFINED) MQTTSNPacket_writeInt(&ptr, topic.data.id); else { MQTTSNPacket_writeChar(&ptr, topic.data.short_name[0]); MQTTSNPacket_writeChar(&ptr, topic.data.short_name[1]); } MQTTSNPacket_writeInt(&ptr, packetid); if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3) { memcpy(ptr, topic.data.long_.name, topic.data.long_.len); ptr += topic.data.long_.len; } memcpy(ptr, payload, payloadlen); ptr += payloadlen; rc = ptr - buf; exit: FUNC_EXIT_RC(rc); return rc; } int MQTTSNSerialize_puback(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid, unsigned char returncode) { unsigned char *ptr = buf; int len = 0; int rc = 0; FUNC_ENTRY; if ((len = MQTTSNPacket_len(6)) > buflen) { rc = MQTTSNPACKET_BUFFER_TOO_SHORT; goto exit; } ptr += MQTTSNPacket_encode(ptr, len); /* write length */ MQTTSNPacket_writeChar(&ptr, MQTTSN_PUBACK); /* write message type */ MQTTSNPacket_writeInt(&ptr, topicid); MQTTSNPacket_writeInt(&ptr, packetid); MQTTSNPacket_writeChar(&ptr, returncode); rc = ptr - buf; exit: FUNC_EXIT_RC(rc); return rc; } /** * Serializes the ack packet into the supplied buffer. * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param type the MQTT-SN packet type * @param packetid the MQTT-SN packet identifier * @return serialized length, or error if 0 */ int MQTTSNSerialize_ack(unsigned char* buf, int buflen, unsigned short packet_type, unsigned short packetid) { int rc = 0; unsigned char *ptr = buf; int len = 4; /* ack packet length */ FUNC_ENTRY; if (len > buflen) { rc = MQTTSNPACKET_BUFFER_TOO_SHORT; goto exit; } ptr += MQTTSNPacket_encode(ptr, len); /* write length */ MQTTSNPacket_writeChar(&ptr, packet_type); /* write packet type */ MQTTSNPacket_writeInt(&ptr, packetid); rc = ptr - buf; exit: FUNC_EXIT_RC(rc); return rc; } /** * Serializes a puback packet into the supplied buffer. * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param packetid integer - the MQTT packet identifier * @return serialized length, or error if 0 */ int MQTTSNSerialize_pubrec(unsigned char* buf, int buflen, unsigned short packetid) { return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBREC, packetid); } /** * Serializes a pubrel packet into the supplied buffer. * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param dup integer - the MQTT dup flag * @param packetid integer - the MQTT packet identifier * @return serialized length, or error if 0 */ int MQTTSNSerialize_pubrel(unsigned char* buf, int buflen, unsigned short packetid) { return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBREL, packetid); } /** * Serializes a pubrel packet into the supplied buffer. * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param packetid integer - the MQTT packet identifier * @return serialized length, or error if 0 */ int MQTTSNSerialize_pubcomp(unsigned char* buf, int buflen, unsigned short packetid) { return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBCOMP, packetid); } /** * Determines the length of the MQTT register packet that would be produced using the supplied parameters * @param topicnamelen the length of the topic name to be used in the register * @return the length of buffer needed to contain the serialized version of the packet */ int MQTTSNSerialize_registerLength(int topicnamelen) { return topicnamelen + 5; } /** * Serializes the supplied register data into the supplied buffer, ready for sending * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param topicid if sent by a gateway, contains the id for the topicname, otherwise 0 * @param packetid integer - the MQTT packet identifier * @param topicname null-terminated topic name string * @return the length of the serialized data. <= 0 indicates error */ int MQTTSNSerialize_register(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid, MQTTSNString* topicname) { unsigned char *ptr = buf; int len = 0; int rc = 0; int topicnamelen = 0; FUNC_ENTRY; topicnamelen = (topicname->cstring) ? strlen(topicname->cstring) : topicname->lenstring.len; if ((len = MQTTSNPacket_len(MQTTSNSerialize_registerLength(topicnamelen))) > buflen) { rc = MQTTSNPACKET_BUFFER_TOO_SHORT; goto exit; } ptr += MQTTSNPacket_encode(ptr, len); /* write length */ MQTTSNPacket_writeChar(&ptr, MQTTSN_REGISTER); /* write message type */ MQTTSNPacket_writeInt(&ptr, topicid); MQTTSNPacket_writeInt(&ptr, packetid); memcpy(ptr, (topicname->cstring) ? topicname->cstring : topicname->lenstring.data, topicnamelen); ptr += topicnamelen; rc = ptr - buf; exit: FUNC_EXIT_RC(rc); return rc; } /** * Serializes the supplied register data into the supplied buffer, ready for sending * @param buf the buffer into which the packet will be serialized * @param buflen the length in bytes of the supplied buffer * @param topicid if sent by a gateway, contains the id for the topicname, otherwise 0 * @param packetid integer - the MQTT packet identifier * @param return_code integer return code * @return the length of the serialized data. <= 0 indicates error */ int MQTTSNSerialize_regack(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid, unsigned char return_code) { unsigned char *ptr = buf; int len = 0; int rc = 0; FUNC_ENTRY; if ((len = MQTTSNPacket_len(6)) > buflen) { rc = MQTTSNPACKET_BUFFER_TOO_SHORT; goto exit; } ptr += MQTTSNPacket_encode(ptr, len); /* write length */ MQTTSNPacket_writeChar(&ptr, MQTTSN_REGACK); /* write message type */ MQTTSNPacket_writeInt(&ptr, topicid); MQTTSNPacket_writeInt(&ptr, packetid); MQTTSNPacket_writeChar(&ptr, return_code); rc = ptr - buf; exit: FUNC_EXIT_RC(rc); return rc; }