mqtt/mqtt.c

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <stdint.h>
#include <math.h>
#include "user_interface.h"
#include "ets_sys.h"
#include "osapi.h"
#include "mem.h"
#include "gpio.h"
#include "espconn.h"
#include "os_type.h"
#include "mqtt.h"
#include "onewire.h"
#include "main.h"

/* Functions we will need to implement:
 * Send -- will handle all sending of all packets
 * Connect -- set up TCP connection and parameters
 * Publish -- send message to server
 * Subscribe -- we probably won't need this
 * We just want to connect, and publish info. We don't care about
 * security or QoS in this basic implementation.
 */

static os_timer_t MQTT_KeepAliveTimer;
static os_timer_t waitForWifiTimer; 

// reverses a string 'str' of length 'len' 
void reverse(char *str, int len) 
{ 
    int i=0, j=len-1, temp; 
    while (i<j) 
    { 
        temp = str[i]; 
        str[i] = str[j]; 
        str[j] = temp; 
        i++; j--; 
    } 
} 
  
 // Converts a given integer x to string str[].  d is the number 
 // of digits required in output. If d is more than the number 
 // of digits in x, then 0s are added at the beginning. 
int intToStr(int x, char str[], int d) 
{ 
    int i = 0; 
    while (x) 
    { 
        str[i++] = (x%10) + '0'; 
        x = x/10; 
    } 
  
    // If number of digits required is more, then 
    // add 0s at the beginning 
    while (i < d) 
        str[i++] = '0'; 
  
    reverse(str, i); 
    str[i] = '\0'; 
    return i; 
} 
  
// Converts a floating point number to string. 
void ftoa(float n, char *res, int afterpoint) 
{ 
    // Extract integer part 
    int ipart = (int)n; 
  
    // Extract floating part 
    float fpart = n - (float)ipart; 
  
    // convert integer part to string 
    int i = intToStr(ipart, res, 0); 
  
    // check for display option after point 
    if (afterpoint != 0) 
    { 
        res[i] = '.';  // add dot 
  
        // Get the value of fraction part upto given no. 
        // of points after dot. The third parameter is needed 
        // to handle cases like 233.007 
        fpart = fpart * pow(10, afterpoint); 
  
        intToStr((int)fpart, res + i + 1, afterpoint); 
    } 
} 

void ICACHE_FLASH_ATTR data_sent_callback(void *arg) {
  os_printf("Data sent!\n");
}

void ICACHE_FLASH_ATTR data_recv_callback(void *arg, char *pdata, unsigned short len) {
  struct espconn *pConn = arg;
  mqtt_session_t *session = pConn->reverse;
  // deal with received data
#ifdef DEBUG
  os_printf("Received data of length %d -- %s \r\n", len, pdata);
  os_printf("Hex dump: ");
  for(int i = 0; i < len; i++) {
    os_printf("(%d): %x ", i, pdata[i]);
  } 
 os_printf("\n");
#endif
  mqtt_message_type msgType = ((mqtt_message_type)pdata[0] >> 4) & 0x0F;
  switch(msgType) {
    case MQTT_MSG_TYPE_CONNACK:
      os_printf("CONNACK recieved...\n");
      switch(pdata[3]) {
	case 0:
	  os_printf("Connection accepted.\n");
	  break;
	case 1:
	  os_printf("Connection refused -- incorrect protocol version.\n");
	  break;
	case 2:
	  os_printf("Connection refused -- illegal identifier.\n");
	  break;
	case 3:
	  os_printf("Connection refused -- broker offline or not available.\n");
	  break;
	case 4:
	  os_printf("Connection refused -- bad username or password.\n");
	  break;
	case 5:
	  os_printf("Connection refused -- not authorized.\n");
	  break;
	default:
	  os_printf("Connection refused -- illegal CONNACK return code.\n");
	  break;
      }
      if(session->connack_cb != NULL) {
	session->connack_cb(pdata);
      }
      break;
    case MQTT_MSG_TYPE_PUBLISH:
      os_printf("Application message from server: %s\n", &pdata[3]); // probably incorrect
      if(session->publish_cb != NULL) {
	session->publish_cb(pdata);
      }
      break;
    case MQTT_MSG_TYPE_SUBACK:
      os_printf("Subscription acknowledged\n");
      break;
    case MQTT_MSG_TYPE_UNSUBACK:
      os_printf("Unsubscription acknowledged\n");
      break;
    case MQTT_MSG_TYPE_PINGRESP:
      os_printf("Pong!\n");
      break;
      // all remaining cases listed to avoid warnings
    case MQTT_MSG_TYPE_CONNECT:
    case MQTT_MSG_TYPE_PUBACK:
    case MQTT_MSG_TYPE_PUBREC:
    case MQTT_MSG_TYPE_PUBREL:
    case MQTT_MSG_TYPE_PUBCOMP:
    case MQTT_MSG_TYPE_SUBSCRIBE:
    case MQTT_MSG_TYPE_UNSUBSCRIBE:
    case MQTT_MSG_TYPE_PINGREQ:
    case MQTT_MSG_TYPE_DISCONNECT:
    default:
      if(msgType == MQTT_MSG_TYPE_DISCONNECT) {
	os_printf("MQTT Disconnect packet\n");
      }
      return;
      break;
  
  }
}

void ICACHE_FLASH_ATTR connected_callback(void *arg) {
  struct espconn *pConn = arg;
  mqtt_session_t *pSession = pConn->reverse;
#ifdef DEBUG
  os_printf("Connected callback\n");
#endif
  espconn_regist_recvcb(pConn, (espconn_recv_callback)data_recv_callback);
  espconn_regist_sentcb(pConn, (espconn_sent_callback)data_sent_callback);
  // enable keepalive
  espconn_set_opt(pConn, ESPCONN_KEEPALIVE);
  pSession->validConnection = 1;
}

void ICACHE_FLASH_ATTR reconnected_callback(void *arg, sint8 err) {
  os_printf("Reconnected?\n");
  os_printf("Error code: %d\n", err);
}

void ICACHE_FLASH_ATTR disconnected_callback(void *arg) {
  os_printf("Disconnected\n");
  os_timer_disarm(&pubTimer);
  os_timer_disarm(&pingTimer);
}

uint8_t ICACHE_FLASH_ATTR tcpConnect(void *arg) {
  os_timer_disarm(&waitForWifiTimer);
  struct ip_info ipConfig;
  mqtt_session_t *session = arg;
  wifi_get_ip_info(STATION_IF, &ipConfig);
  if (wifi_station_get_connect_status() == STATION_GOT_IP && ipConfig.ip.addr != 0) {
    LOCAL struct espconn conn;
    LOCAL struct _esp_tcp tcp_s;
    conn.reverse = arg;
    os_printf("Everything looks good!\n");
#ifdef DEBUG
    os_printf("Entered tcpConnect\n");
#endif
    wifi_get_ip_info(STATION_IF, &ipConfig);
    // set up basic TCP connection parameters
#ifdef DEBUG
    os_printf("about to set up TCP params\n");
#endif
    conn.proto.tcp = &tcp_s;
    conn.type = ESPCONN_TCP;
    conn.proto.tcp->local_port = espconn_port();
    conn.proto.tcp->remote_port = session->port;
    conn.state = ESPCONN_NONE;
    os_memcpy(conn.proto.tcp->remote_ip, session->ip, 4);
    
    os_printf("About to register callbacks\n");
    // register callbacks
    espconn_regist_connectcb(&conn, (espconn_connect_callback)connected_callback);
    espconn_regist_reconcb(&conn, (espconn_reconnect_callback)reconnected_callback);
    espconn_regist_disconcb(&conn, (espconn_connect_callback)disconnected_callback);
    os_printf("About to connect\n");
    //make the connection
    if(espconn_connect(&conn) == 0) {
      os_printf("Connection successful\n");
    } else {
      os_printf("Connection error\n");
    }
    session->activeConnection = &conn;
#ifdef DEBUG
    os_printf("About to return from TCP connect\n");
#endif
    return 0;
  }
  else {
    // set timer to try again
    os_timer_setfn(&waitForWifiTimer, (os_timer_func_t *)tcpConnect, session);
    os_timer_arm(&waitForWifiTimer, 1000, 0);
    return 2;
  }
  return 0;
}


uint8_t ICACHE_FLASH_ATTR *encodeLength(uint32_t trueLength) {
  uint8_t *encodedByte = os_zalloc(sizeof(uint8_t) * 5); // can't be more than 5 bytes
  uint8_t numBytes = 1;
  do {
    encodedByte[numBytes] = trueLength % 128;
    trueLength /= 128;
    if(trueLength > 0) {
      encodedByte[numBytes] |= 128;
    }
    numBytes++;
  } while(trueLength > 0);
  encodedByte[0] = numBytes - 1;
  
  return encodedByte;

}

void ICACHE_FLASH_ATTR pingAlive(void *arg) {
  mqtt_session_t *pSession = (mqtt_session_t *)arg;
  mqtt_send(pSession, NULL, 0, MQTT_MSG_TYPE_PINGREQ);
}

uint8_t ICACHE_FLASH_ATTR mqtt_send(mqtt_session_t *session, uint8_t *data, uint32_t len, mqtt_message_type msgType) {
  if(session->validConnection == 1) {
    os_timer_disarm(&MQTT_KeepAliveTimer); // disable timer if we are called
#ifdef DEBUG
    os_printf("Entering mqtt_send!\n");
#endif
    LOCAL mqtt_packet_t packet;
    LOCAL mqtt_packet_t *pPacket = &packet;
    uint8_t *fullPacket;
    uint8_t *remaining_len_encoded;
    switch(msgType) {
      case MQTT_MSG_TYPE_CONNECT: {
	const uint8_t varDefaults[10] = { 0x00, 0x04, 0x4D, 0x51, 0x54, 0x54, 0x04, 0xC2, 0x00, 0x32 }; // variable header is always the same for Connect
	pPacket->fixedHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * 5); // fixed header cannot be longer than 5
	pPacket->fixedHeader[0] = ((uint8_t)msgType << 4) & 0xF0; // make sure lower 4 are clear
	// prepare variable header
	pPacket->varHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * 10); // 10 bytes for connect
	os_memcpy(pPacket->varHeader, varDefaults, 10); // copy defaults
	pPacket->varHeader_len = 10;
	// prepare payload
	uint32_t offset = 0; // keep track of how many bytes we have copied
	uint32_t maxPayloadLength = session->client_id_len + session->username_len + session->password_len + 12; // length info can only take a maximum of 12 bytes
	pPacket->payload = (uint8_t *)os_zalloc(sizeof(uint8_t) * maxPayloadLength);
	// copy client id to payload: 2 bytes for size, then client id. 
	// insert a 0
	os_memset(pPacket->payload + offset, 0, 1); // MSB is always 0
	offset += 1;
	os_memcpy(pPacket->payload + offset, &session->client_id_len, 1); // LSB is length of string
	offset += 1;
	os_memcpy(pPacket->payload + offset, session->client_id, session->client_id_len); // and copy string
	offset += session->client_id_len;
	// copy username to payload: same as client id, 2 bytes for size, then username
	// insert a 0
	os_memset(pPacket->payload + offset, 0, 1);
	offset += 1;
	os_memcpy(pPacket->payload + offset, &session->username_len, 1);
	offset += 1;
	os_memcpy(pPacket->payload + offset, session->username, session->username_len);
	offset += session->username_len;
	// Password: same as username and client id, 2 bytes for size, then password
	// insert a 0
	os_memset(pPacket->payload + offset, 0, 1);
	offset += 1;
	os_memcpy(pPacket->payload + offset, &session->password_len, 1);
	offset += 1;
	os_memcpy(pPacket->payload + offset, session->password, session->password_len);
	offset += session->password_len;
	pPacket->payload_len = offset; // the length of the payload is the same as our offset
#ifdef DEBUG
	os_printf("Total offset: %d\n", offset);
#endif
	// the remaining length is the size of the packet, minus the first byte and the bytes taken by the remaining length bytes themselves
	// they are encoded per the MQTT spec, section 2.2.3
	// the first byte returned by encodeLength is the number of bytes to follow, as it can be anywhere from 1 to 4 bytes to encode the length
	remaining_len_encoded = encodeLength((uint32_t)(pPacket->varHeader_len + pPacket->payload_len));
	os_memcpy(pPacket->fixedHeader + 1, remaining_len_encoded + 1, remaining_len_encoded[0]);
	pPacket->fixedHeader_len = remaining_len_encoded[0] + 1; // fixed header length is the number of bytes used to encode the remaining length, plus 1 for the fixed CONNECT byte
	// the full length is the length of the varHeader, payload, and fixedHeader
	pPacket->length = (pPacket->varHeader_len + pPacket->payload_len + pPacket->fixedHeader_len);
#ifdef DEBUG
	os_printf("Packet length: %d\n", pPacket->length);
#endif
	// construct packet data
	fullPacket = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->length);
	os_memcpy(fullPacket, pPacket->fixedHeader, pPacket->fixedHeader_len);
	os_memcpy(fullPacket + pPacket->fixedHeader_len, pPacket->varHeader, pPacket->varHeader_len);
	os_memcpy(fullPacket + pPacket->fixedHeader_len + pPacket->varHeader_len, pPacket->payload, pPacket->payload_len);
	break;
      }
      case MQTT_MSG_TYPE_PUBLISH: {
	// prepare for publish
	pPacket->fixedHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * 5);
	pPacket->fixedHeader[0] = (MQTT_MSG_TYPE_PUBLISH << 4) & 0xF0; // clear lower 4 bits, we don't need DUP, QOS or RETAIN
	
	// variable header
	// A PUBLISH Packet MUST NOT contain a Packet Identifier if its QoS value is set to 0 [MQTT-2.3.1-5].
	pPacket->varHeader_len = session->topic_name_len + 2; // we have no packet identifier, as we are QOS 0
	pPacket->varHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->varHeader_len);
	os_memset(pPacket->varHeader, 0, 1);
	os_memcpy(pPacket->varHeader + 1, &session->topic_name_len, 1);
	os_memcpy(pPacket->varHeader + 2, session->topic_name, session->topic_name_len);
	
	//payload
	pPacket->payload_len = len;
	pPacket->payload = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->payload_len);
	os_memcpy(pPacket->payload, data, pPacket->payload_len);
	// calculate remaining length for fixed header
	remaining_len_encoded = encodeLength((uint32_t)(pPacket->varHeader_len + pPacket->payload_len));
	os_memcpy(pPacket->fixedHeader + 1, remaining_len_encoded + 1, remaining_len_encoded[0]);
	pPacket->fixedHeader_len = remaining_len_encoded[0] + 1; // fixed header length is the number of bytes used to encode the remaining length, plus 1 for the fixed CONNECT byte
	// the full length is the length of the varHeader, payload, and fixedHeader
	pPacket->length = (pPacket->varHeader_len + pPacket->payload_len + pPacket->fixedHeader_len);
	os_printf("Packet length: %d\n", pPacket->length);
	// construct packet data
	fullPacket = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->length);
	os_memcpy(fullPacket, pPacket->fixedHeader, pPacket->fixedHeader_len);
	os_memcpy(fullPacket + pPacket->fixedHeader_len, pPacket->varHeader, pPacket->varHeader_len);
	os_memcpy(fullPacket + pPacket->fixedHeader_len + pPacket->varHeader_len, pPacket->payload, pPacket->payload_len);
	break;
      }
      case MQTT_MSG_TYPE_SUBSCRIBE:
      case MQTT_MSG_TYPE_UNSUBSCRIBE:
	// prepare for subscribe
	pPacket->fixedHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * 5);
	pPacket->fixedHeader[0] = ((msgType << 4) & 0xF0) | 0x02;
	
	pPacket->varHeader_len = 2;
	pPacket->varHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->varHeader_len);
	os_memset(pPacket->varHeader, 0, 2); // set packet ID to 0
	
	uint8_t extraByte = (msgType == MQTT_MSG_TYPE_SUBSCRIBE) ? 3 : 2;
	pPacket->payload_len = session->topic_name_len + extraByte;
	pPacket->payload = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->payload_len);
	pPacket->payload[1] = session->topic_name_len % 0xFF;
	pPacket->payload[0] = session->topic_name_len / 0xFF;
	os_memcpy(pPacket->payload + 2, session->topic_name, session->topic_name_len); // copy topic name
	if(msgType == MQTT_MSG_TYPE_SUBSCRIBE) pPacket->payload[session->topic_name_len+2] = 0;
	
	// calculate remaining length for fixed header
	remaining_len_encoded = encodeLength((uint32_t)(pPacket->varHeader_len + pPacket->payload_len));
	os_memcpy(pPacket->fixedHeader + 1, remaining_len_encoded + 1, remaining_len_encoded[0]);
	pPacket->fixedHeader_len = remaining_len_encoded[0] + 1; // fixed header length is the number of bytes used to encode the remaining length, plus 1 for the fixed CONNECT byte
	// the full length is the length of the varHeader, payload, and fixedHeader
	pPacket->length = (pPacket->varHeader_len + pPacket->payload_len + pPacket->fixedHeader_len);
	os_printf("Packet length: %d\n", pPacket->length);
	// construct packet data
	fullPacket = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->length);
	os_memcpy(fullPacket, pPacket->fixedHeader, pPacket->fixedHeader_len);
	os_memcpy(fullPacket + pPacket->fixedHeader_len, pPacket->varHeader, pPacket->varHeader_len);
	os_memcpy(fullPacket + pPacket->fixedHeader_len + pPacket->varHeader_len, pPacket->payload, pPacket->payload_len);
	
	break;
      case MQTT_MSG_TYPE_PINGREQ:
      case MQTT_MSG_TYPE_DISCONNECT:
	// PINGREQ has no varHeader or payload, it's just two bytes
	// 0xC0 0x00
	pPacket->fixedHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * 2);
	pPacket->fixedHeader[0] = (msgType << 4) & 0xF0; // bottom nibble must be clear
	pPacket->fixedHeader[1] = 0; // remaining length is zero
	pPacket->fixedHeader_len = 2;
	pPacket->length = pPacket->fixedHeader_len;
	// In order to avoid undefined behaviour, we must allocate
	// something to varHeader and payload, as they get passed
	// to free() at the end of this function
	pPacket->varHeader = (uint8_t *)os_zalloc(1);
	pPacket->payload = (uint8_t *)os_zalloc(1);
	// copy the fixedHeader to fullPacket, and we're done!
	fullPacket = (uint8_t *)os_zalloc(sizeof(uint8_t) * pPacket->length);
	os_memcpy(fullPacket, pPacket->fixedHeader, pPacket->fixedHeader_len);
	break;
      default:
	// something has gone wrong
	os_printf("Attempt to send incorrect packet type: %d", (uint8_t)msgType);
	return -1;
    }
#ifdef DEBUG
    os_printf("About to send MQTT command type: %d...\n", (uint8_t)msgType);
#endif
    espconn_send(session->activeConnection, fullPacket, pPacket->length);
    os_free(fullPacket);
    os_free(pPacket->fixedHeader);
    os_free(pPacket->varHeader);
    os_free(pPacket->payload);
    // set up keepalive timer
    if(msgType != MQTT_MSG_TYPE_DISCONNECT) {
      os_timer_setfn(&MQTT_KeepAliveTimer, (os_timer_func_t *)pingAlive, session);
      os_timer_arm(&MQTT_KeepAliveTimer, 30000, 0);
    }
  } else {
    os_printf("No wifi! Narf!\n");
  }
  return 0;
}