515 lines
14 KiB
C
515 lines
14 KiB
C
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/*******************************************************************************
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* Copyright (c) 2014 IBM Corp.
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*
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* and Eclipse Distribution License v1.0 which accompany this distribution.
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*
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* The Eclipse Public License is available at
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* http://www.eclipse.org/legal/epl-v10.html
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* and the Eclipse Distribution License is available at
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* http://www.eclipse.org/org/documents/edl-v10.php.
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*
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* Contributors:
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* Allan Stockdill-Mander/Ian Craggs - initial API and implementation and/or initial documentation
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*******************************************************************************/
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#include "MQTTClient.h"
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void NewMessageData(MessageData* md, MQTTString* aTopicName, MQTTMessage* aMessgage) {
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md->topicName = aTopicName;
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md->message = aMessgage;
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}
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int getNextPacketId(Client *c) {
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return c->next_packetid = (c->next_packetid == MAX_PACKET_ID) ? 1 : c->next_packetid + 1;
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}
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int sendPacket(Client* c, int length, Timer* timer)
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{
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int rc = FAILURE,
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sent = 0;
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while (sent < length && !expired(timer))
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{
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rc = c->ipstack->mqttwrite(c->ipstack, &c->buf[sent], length, left_ms(timer));
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if (rc < 0) // there was an error writing the data
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break;
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sent += rc;
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}
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if (sent == length)
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{
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countdown(&c->ping_timer, c->keepAliveInterval); // record the fact that we have successfully sent the packet
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rc = SUCCESS;
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}
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else
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rc = FAILURE;
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return rc;
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}
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void MQTTClient(Client* c, Network* network, unsigned int command_timeout_ms, unsigned char* buf, size_t buf_size, unsigned char* readbuf, size_t readbuf_size)
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{
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int i;
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c->ipstack = network;
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for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
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c->messageHandlers[i].topicFilter = 0;
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c->command_timeout_ms = command_timeout_ms;
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c->buf = buf;
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c->buf_size = buf_size;
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c->readbuf = readbuf;
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c->readbuf_size = readbuf_size;
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c->isconnected = 0;
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c->ping_outstanding = 0;
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c->defaultMessageHandler = NULL;
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InitTimer(&c->ping_timer);
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}
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int decodePacket(Client* c, int* value, int timeout)
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{
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unsigned char i;
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int multiplier = 1;
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int len = 0;
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const int MAX_NO_OF_REMAINING_LENGTH_BYTES = 4;
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*value = 0;
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do
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{
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int rc = MQTTPACKET_READ_ERROR;
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if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES)
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{
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rc = MQTTPACKET_READ_ERROR; /* bad data */
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goto exit;
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}
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rc = c->ipstack->mqttread(c->ipstack, &i, 1, timeout);
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if (rc != 1)
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goto exit;
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*value += (i & 127) * multiplier;
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multiplier *= 128;
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} while ((i & 128) != 0);
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exit:
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return len;
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}
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int readPacket(Client* c, Timer* timer)
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{
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int rc = FAILURE;
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MQTTHeader header = {0};
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int len = 0;
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int rem_len = 0;
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/* 1. read the header byte. This has the packet type in it */
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if (c->ipstack->mqttread(c->ipstack, c->readbuf, 1, left_ms(timer)) != 1)
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goto exit;
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len = 1;
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/* 2. read the remaining length. This is variable in itself */
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decodePacket(c, &rem_len, left_ms(timer));
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len += MQTTPacket_encode(c->readbuf + 1, rem_len); /* put the original remaining length back into the buffer */
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/* 3. read the rest of the buffer using a callback to supply the rest of the data */
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if (rem_len > 0 && (c->ipstack->mqttread(c->ipstack, c->readbuf + len, rem_len, left_ms(timer)) != rem_len))
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goto exit;
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header.byte = c->readbuf[0];
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rc = header.bits.type;
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exit:
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return rc;
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}
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// assume topic filter and name is in correct format
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// # can only be at end
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// + and # can only be next to separator
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char isTopicMatched(char* topicFilter, MQTTString* topicName)
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{
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char* curf = topicFilter;
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char* curn = topicName->lenstring.data;
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char* curn_end = curn + topicName->lenstring.len;
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while (*curf && curn < curn_end)
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{
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if (*curn == '/' && *curf != '/')
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break;
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if (*curf != '+' && *curf != '#' && *curf != *curn)
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break;
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if (*curf == '+')
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{ // skip until we meet the next separator, or end of string
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char* nextpos = curn + 1;
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while (nextpos < curn_end && *nextpos != '/')
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nextpos = ++curn + 1;
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}
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else if (*curf == '#')
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curn = curn_end - 1; // skip until end of string
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curf++;
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curn++;
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};
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return (curn == curn_end) && (*curf == '\0');
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}
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int deliverMessage(Client* c, MQTTString* topicName, MQTTMessage* message)
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{
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int i;
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int rc = FAILURE;
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// we have to find the right message handler - indexed by topic
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for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
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{
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if (c->messageHandlers[i].topicFilter != 0 && (MQTTPacket_equals(topicName, (char*)c->messageHandlers[i].topicFilter) ||
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isTopicMatched((char*)c->messageHandlers[i].topicFilter, topicName)))
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{
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if (c->messageHandlers[i].fp != NULL)
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{
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MessageData md;
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NewMessageData(&md, topicName, message);
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c->messageHandlers[i].fp(&md);
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rc = SUCCESS;
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}
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}
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}
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if (rc == FAILURE && c->defaultMessageHandler != NULL)
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{
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MessageData md;
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NewMessageData(&md, topicName, message);
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c->defaultMessageHandler(&md);
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rc = SUCCESS;
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}
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return rc;
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}
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int keepalive(Client* c)
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{
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int rc = FAILURE;
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if (c->keepAliveInterval == 0)
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{
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rc = SUCCESS;
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goto exit;
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}
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if (expired(&c->ping_timer))
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{
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if (!c->ping_outstanding)
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{
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Timer timer;
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InitTimer(&timer);
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countdown_ms(&timer, 1000);
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int len = MQTTSerialize_pingreq(c->buf, c->buf_size);
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if (len > 0 && (rc = sendPacket(c, len, &timer)) == SUCCESS) // send the ping packet
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c->ping_outstanding = 1;
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}
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}
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exit:
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return rc;
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}
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int cycle(Client* c, Timer* timer)
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{
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// read the socket, see what work is due
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unsigned short packet_type = readPacket(c, timer);
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int len = 0,
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rc = SUCCESS;
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switch (packet_type)
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{
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case CONNACK:
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case PUBACK:
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case SUBACK:
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break;
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case PUBLISH:
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{
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MQTTString topicName;
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MQTTMessage msg;
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if (MQTTDeserialize_publish((unsigned char*)&msg.dup, (int*)&msg.qos, (unsigned char*)&msg.retained, (unsigned short*)&msg.id, &topicName,
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(unsigned char**)&msg.payload, (int*)&msg.payloadlen, c->readbuf, c->readbuf_size) != 1)
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goto exit;
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deliverMessage(c, &topicName, &msg);
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if (msg.qos != QOS0)
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{
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if (msg.qos == QOS1)
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len = MQTTSerialize_ack(c->buf, c->buf_size, PUBACK, 0, msg.id);
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else if (msg.qos == QOS2)
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len = MQTTSerialize_ack(c->buf, c->buf_size, PUBREC, 0, msg.id);
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if (len <= 0)
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rc = FAILURE;
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else
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rc = sendPacket(c, len, timer);
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if (rc == FAILURE)
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goto exit; // there was a problem
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}
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break;
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}
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case PUBREC:
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{
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unsigned short mypacketid;
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unsigned char dup, type;
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if (MQTTDeserialize_ack(&type, &dup, &mypacketid, c->readbuf, c->readbuf_size) != 1)
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rc = FAILURE;
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else if ((len = MQTTSerialize_ack(c->buf, c->buf_size, PUBREL, 0, mypacketid)) <= 0)
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rc = FAILURE;
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else if ((rc = sendPacket(c, len, timer)) != SUCCESS) // send the PUBREL packet
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rc = FAILURE; // there was a problem
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if (rc == FAILURE)
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goto exit; // there was a problem
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break;
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}
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case PUBCOMP:
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break;
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case PINGRESP:
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c->ping_outstanding = 0;
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break;
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}
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keepalive(c);
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exit:
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if (rc == SUCCESS)
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rc = packet_type;
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return rc;
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}
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int MQTTYield(Client* c, int timeout_ms)
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{
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int rc = SUCCESS;
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Timer timer;
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InitTimer(&timer);
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countdown_ms(&timer, timeout_ms);
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while (!expired(&timer))
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{
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if (cycle(c, &timer) == FAILURE)
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{
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rc = FAILURE;
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break;
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}
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}
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return rc;
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}
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// only used in single-threaded mode where one command at a time is in process
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int waitfor(Client* c, int packet_type, Timer* timer)
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{
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int rc = FAILURE;
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do
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{
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if (expired(timer))
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break; // we timed out
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}
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while ((rc = cycle(c, timer)) != packet_type);
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return rc;
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}
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int MQTTConnect(Client* c, MQTTPacket_connectData* options)
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{
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Timer connect_timer;
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int rc = FAILURE;
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MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer;
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int len = 0;
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InitTimer(&connect_timer);
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countdown_ms(&connect_timer, c->command_timeout_ms);
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if (c->isconnected) // don't send connect packet again if we are already connected
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goto exit;
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if (options == 0)
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options = &default_options; // set default options if none were supplied
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c->keepAliveInterval = options->keepAliveInterval;
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countdown(&c->ping_timer, c->keepAliveInterval);
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if ((len = MQTTSerialize_connect(c->buf, c->buf_size, options)) <= 0)
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goto exit;
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if ((rc = sendPacket(c, len, &connect_timer)) != SUCCESS) // send the connect packet
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goto exit; // there was a problem
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// this will be a blocking call, wait for the connack
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if (waitfor(c, CONNACK, &connect_timer) == CONNACK)
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{
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unsigned char connack_rc = 255;
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char sessionPresent = 0;
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if (MQTTDeserialize_connack((unsigned char*)&sessionPresent, &connack_rc, c->readbuf, c->readbuf_size) == 1)
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rc = connack_rc;
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else
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rc = FAILURE;
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}
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else
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rc = FAILURE;
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exit:
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if (rc == SUCCESS)
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c->isconnected = 1;
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return rc;
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}
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int MQTTSubscribe(Client* c, const char* topicFilter, enum QoS qos, messageHandler messageHandler)
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{
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int rc = FAILURE;
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Timer timer;
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int len = 0;
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MQTTString topic = MQTTString_initializer;
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topic.cstring = (char *)topicFilter;
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InitTimer(&timer);
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countdown_ms(&timer, c->command_timeout_ms);
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if (!c->isconnected)
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goto exit;
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len = MQTTSerialize_subscribe(c->buf, c->buf_size, 0, getNextPacketId(c), 1, &topic, (int*)&qos);
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if (len <= 0)
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goto exit;
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if ((rc = sendPacket(c, len, &timer)) != SUCCESS) // send the subscribe packet
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goto exit; // there was a problem
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if (waitfor(c, SUBACK, &timer) == SUBACK) // wait for suback
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{
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int count = 0, grantedQoS = -1;
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unsigned short mypacketid;
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|
|
if (MQTTDeserialize_suback(&mypacketid, 1, &count, &grantedQoS, c->readbuf, c->readbuf_size) == 1)
|
||
|
|
rc = grantedQoS; // 0, 1, 2 or 0x80
|
||
|
|
if (rc != 0x80)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
|
||
|
|
{
|
||
|
|
if (c->messageHandlers[i].topicFilter == 0)
|
||
|
|
{
|
||
|
|
c->messageHandlers[i].topicFilter = topicFilter;
|
||
|
|
c->messageHandlers[i].fp = messageHandler;
|
||
|
|
rc = 0;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
rc = FAILURE;
|
||
|
|
|
||
|
|
exit:
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
int MQTTUnsubscribe(Client* c, const char* topicFilter)
|
||
|
|
{
|
||
|
|
int rc = FAILURE;
|
||
|
|
Timer timer;
|
||
|
|
MQTTString topic = MQTTString_initializer;
|
||
|
|
topic.cstring = (char *)topicFilter;
|
||
|
|
int len = 0;
|
||
|
|
|
||
|
|
InitTimer(&timer);
|
||
|
|
countdown_ms(&timer, c->command_timeout_ms);
|
||
|
|
|
||
|
|
if (!c->isconnected)
|
||
|
|
goto exit;
|
||
|
|
|
||
|
|
if ((len = MQTTSerialize_unsubscribe(c->buf, c->buf_size, 0, getNextPacketId(c), 1, &topic)) <= 0)
|
||
|
|
goto exit;
|
||
|
|
if ((rc = sendPacket(c, len, &timer)) != SUCCESS) // send the subscribe packet
|
||
|
|
goto exit; // there was a problem
|
||
|
|
|
||
|
|
if (waitfor(c, UNSUBACK, &timer) == UNSUBACK)
|
||
|
|
{
|
||
|
|
unsigned short mypacketid; // should be the same as the packetid above
|
||
|
|
if (MQTTDeserialize_unsuback(&mypacketid, c->readbuf, c->readbuf_size) == 1)
|
||
|
|
rc = 0;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
rc = FAILURE;
|
||
|
|
|
||
|
|
exit:
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
int MQTTPublish(Client* c, const char* topicName, MQTTMessage* message)
|
||
|
|
{
|
||
|
|
int rc = FAILURE;
|
||
|
|
Timer timer;
|
||
|
|
MQTTString topic = MQTTString_initializer;
|
||
|
|
topic.cstring = (char *)topicName;
|
||
|
|
int len = 0;
|
||
|
|
|
||
|
|
InitTimer(&timer);
|
||
|
|
countdown_ms(&timer, c->command_timeout_ms);
|
||
|
|
|
||
|
|
if (!c->isconnected)
|
||
|
|
goto exit;
|
||
|
|
|
||
|
|
if (message->qos == QOS1 || message->qos == QOS2)
|
||
|
|
message->id = getNextPacketId(c);
|
||
|
|
|
||
|
|
len = MQTTSerialize_publish(c->buf, c->buf_size, 0, message->qos, message->retained, message->id,
|
||
|
|
topic, (unsigned char*)message->payload, message->payloadlen);
|
||
|
|
if (len <= 0)
|
||
|
|
goto exit;
|
||
|
|
if ((rc = sendPacket(c, len, &timer)) != SUCCESS) // send the subscribe packet
|
||
|
|
goto exit; // there was a problem
|
||
|
|
|
||
|
|
if (message->qos == QOS1)
|
||
|
|
{
|
||
|
|
if (waitfor(c, PUBACK, &timer) == PUBACK)
|
||
|
|
{
|
||
|
|
unsigned short mypacketid;
|
||
|
|
unsigned char dup, type;
|
||
|
|
if (MQTTDeserialize_ack(&type, &dup, &mypacketid, c->readbuf, c->readbuf_size) != 1)
|
||
|
|
rc = FAILURE;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
rc = FAILURE;
|
||
|
|
}
|
||
|
|
else if (message->qos == QOS2)
|
||
|
|
{
|
||
|
|
if (waitfor(c, PUBCOMP, &timer) == PUBCOMP)
|
||
|
|
{
|
||
|
|
unsigned short mypacketid;
|
||
|
|
unsigned char dup, type;
|
||
|
|
if (MQTTDeserialize_ack(&type, &dup, &mypacketid, c->readbuf, c->readbuf_size) != 1)
|
||
|
|
rc = FAILURE;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
rc = FAILURE;
|
||
|
|
}
|
||
|
|
|
||
|
|
exit:
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
int MQTTDisconnect(Client* c)
|
||
|
|
{
|
||
|
|
int rc = FAILURE;
|
||
|
|
Timer timer; // we might wait for incomplete incoming publishes to complete
|
||
|
|
int len = MQTTSerialize_disconnect(c->buf, c->buf_size);
|
||
|
|
|
||
|
|
InitTimer(&timer);
|
||
|
|
countdown_ms(&timer, c->command_timeout_ms);
|
||
|
|
|
||
|
|
if (len > 0)
|
||
|
|
rc = sendPacket(c, len, &timer); // send the disconnect packet
|
||
|
|
|
||
|
|
c->isconnected = 0;
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|