Rewritten code works! See full log.

After much consternation, finally got the code generalized. For
some reason the ESP8266 absolutely cannot pass pointers between
functions. I'm not sure if this is because it's a timer function?
Either way, we have to memcpy the values, which makes things a
bit messier, but not too bad.

Now to start work on Publish...

mqtt.c

@@ -8,6 +8,7 @@
 #include "os_type.h"
 #include "mqtt.h"
 
+#define DEBUG 1
 /* Functions we will need to implement:
  * Send -- will handle all sending of all packets
  * Connect -- set up TCP connection and parameters
@@ -87,6 +88,33 @@ LOCAL uint8_t ICACHE_FLASH_ATTR mqtt_connect(mqtt_session_t *session, uint8_t *u
     
 }
 
+/************************************************************************************************/
+/* Function: encodeLength								        */
+/* Parameters: the length in bytes							        */
+/* Returns: encoded multi-byte number per MQTT standards. The first byte this pointer	        */
+/* returns is the number of bytes to follow.						        */
+/* The MQTT standard uses a very strange method of encoding the lengths of the various sections */
+/* of the packets. This makes it simpler to implement in code.				        */
+/************************************************************************************************/
+
+
+LOCAL 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;
+
+}
+
 /*************************************************************************************/
 /* Function: mqtt_send								     */
 /* Parameters: active mqtt_session_t, pointer to data, data length, and message type */
@@ -98,68 +126,63 @@ LOCAL uint8_t ICACHE_FLASH_ATTR mqtt_send(mqtt_session_t *session, uint8_t *data
   /** First thing to do is check the packet type.
    * This will inform everything else we do
    */
+#ifdef DEBUG
   os_printf("Entering mqtt_send!\n");
+#endif
   LOCAL mqtt_packet_t packet;
   LOCAL mqtt_packet_t *pPacket = &packet;
   uint8_t *fullPacket;
   switch(msgType) {
-  case MQTT_MSG_TYPE_CONNECT:
+    case MQTT_MSG_TYPE_CONNECT: ;
     // prepare packet for connect type
-    pPacket->fixedHeader = (uint8_t *)os_zalloc(sizeof(uint8_t) * 2); // fixed header cannot be longer than 5
+      const uint8_t varDefaults[10] = { 0x00, 0x04, 0x4D, 0x51, 0x54, 0x54, 0x04, 0xC2, 0x00, 0x32 };
+      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 = os_zalloc(sizeof(uint8_t) * 10); // 10 bytes for connect
-    pPacket->varHeader[0] = 0;
+      os_memcpy(pPacket->varHeader, varDefaults, 10); // copy defaults
-    pPacket->varHeader[1] = 4; // length of protocol name
-    pPacket->varHeader[2] = 0x4D; // M
-    pPacket->varHeader[3] = 0x51; // Q
-    pPacket->varHeader[4] = 0x54; // T
-    pPacket->varHeader[5] = 0x54; // T
-    pPacket->varHeader[6] = 4; // protocol level
-    pPacket->varHeader[7] = 0b11000010; // connect flags, no QOS or will, clean session, user/pass
-    pPacket->varHeader[8] = 0;
-    pPacket->varHeader[9] = 10; // keepalive time
       pPacket->varHeader_len = 10;
       // prepare payload
-    pPacket->payload = (uint8_t *)os_zalloc(sizeof(uint8_t) * 26);
+      uint32_t offset = 0;
-    // client identifier "FRZN0"
+      uint32_t maxPayloadLength = session->client_id_len + session->username_len + session->password_len + 12; // length can only take a maximum of 12 bytes
-    pPacket->payload[0] = 0;
+      pPacket->payload = (uint8_t *)os_zalloc(sizeof(uint8_t) * maxPayloadLength);
-    pPacket->payload[1] = 5;
+      // copy client id to payload
-    pPacket->payload[2] = 0x46; // F
+      // insert a 0
-    pPacket->payload[3] = 0x52; // R
+      os_memset(pPacket->payload + offset, 0, 1);
-    pPacket->payload[4] = 0x5A; // Z
+      offset += 1;
-    pPacket->payload[5] = 0x4E; // N
+      os_memcpy(pPacket->payload + offset, &session->client_id_len, 1);
-    pPacket->payload[6] = 0x30; // 0
+      offset += 1;
-    // Username
+      os_memcpy(pPacket->payload + offset, session->client_id, session->client_id_len);
-    pPacket->payload[7] = 0;
+      offset += session->client_id_len;
-    pPacket->payload[8] = 11;
+      // copy username to payload
-    // os_memcpy(pPacket->payload + 9, data, username_len);
+      // insert a 0
-    pPacket->payload[9] = 0x4D; // M
+      os_memset(pPacket->payload + offset, 0, 1);
-    pPacket->payload[10] = 0x72; // r
+      offset += 1;
-    pPacket->payload[11] = 0x41; // A
+      os_memcpy(pPacket->payload + offset, &session->username_len, 1);
-    pPacket->payload[12] = 0x75; // u
+      offset += 1;
-    pPacket->payload[13] = 0x72; // r
+      os_memcpy(pPacket->payload + offset, session->username, session->username_len);
-    pPacket->payload[14] = 0x65; // e
+      offset += session->username_len;
-    pPacket->payload[15] = 0x6C; // l
-    pPacket->payload[16] = 0x69; // i
-    pPacket->payload[17] = 0x75; // u
-    pPacket->payload[18] = 0x73; // s
-    pPacket->payload[19] = 0x52; // R
       // Password
-    pPacket->payload[20] = 0;
+      // insert a 0
-    pPacket->payload[21] = 4;
+      os_memset(pPacket->payload + offset, 0, 1);
-    // os_memcpy(pPacket->payload + 22, data + offset, password_len);
+      offset += 1;
-    pPacket->payload[22] = 0x74; // t
+      os_memcpy(pPacket->payload + offset, &session->password_len, 1);
-    pPacket->payload[23] = 0x65; // e
+      offset += 1;
-    pPacket->payload[24] = 0x73; // s
+      os_memcpy(pPacket->payload + offset, session->password, session->password_len);
-    pPacket->payload[25] = 0x74; // t
+      offset += session->password_len;
-    pPacket->payload_len = 26;
+      pPacket->payload_len = offset;
-    pPacket->fixedHeader[1] = 36; // length of varHeader + payload_len
+      os_printf("Total offset: %d", offset);
-    pPacket->length = 38;
+      uint8_t *remaining_len_encoded = encodeLength((uint32_t)(pPacket->varHeader_len + pPacket->payload_len));
-    fullPacket = os_zalloc(sizeof(uint8_t) * pPacket->length); //full packet length is 38
+      os_memcpy(pPacket->fixedHeader + 1, remaining_len_encoded + 1, remaining_len_encoded[0]); // remaining length = length of varHeader + length of payload
-    os_memcpy(fullPacket, pPacket->fixedHeader, 2);
+      pPacket->fixedHeader_len = remaining_len_encoded[0] + 1;
-    os_memcpy(fullPacket + 2, pPacket->varHeader, 10);
+      // the full length is the length of the varHeader, payload, and fixedHeader
-    os_memcpy(fullPacket + 12, pPacket->payload, 26);
+      pPacket->length = (pPacket->varHeader_len + pPacket->payload_len + pPacket->fixedHeader_len);
+      os_printf("Packet length: %d\n", pPacket->length);
+      // construct packet data
+      fullPacket = 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
@@ -181,9 +204,14 @@ LOCAL uint8_t ICACHE_FLASH_ATTR mqtt_send(mqtt_session_t *session, uint8_t *data
       os_printf("Attempt to send incorrect packet type: %d", (uint8_t)msgType);
       return -1;
   }
+#ifdef DEBUG
   os_printf("About to send MQTT connect...\n");
+#endif
   espconn_send(session->activeConnection, fullPacket, pPacket->length);
   os_free(fullPacket);
+  os_free(pPacket->fixedHeader);
+  os_free(pPacket->varHeader);
+  os_free(pPacket->payload);
 }
 
 LOCAL void ICACHE_FLASH_ATTR test(void *arg) {
@@ -209,17 +237,31 @@ void ICACHE_FLASH_ATTR user_init() {
   
   // prepare the TCP/MQTT connection stuff
   // test server is at 51.15.65.206
-  char testUser[] = "MrAureliusR";
+  char testUser[11] = { 0x4d, 0x72, 0x41, 0x75, 0x72, 0x65, 0x6c, 0x69, 0x75, 0x73, 0x52 };
-  char testPass[] = "test";
+  char *pTestUser = testUser;
-  char testTopic[] = "input";
+  char testPass[4] = { 0x74, 0x65, 0x73, 0x74 };
-  pGlobalSession->port = 1883; // port 80 just for testing
+  char *pTestPass = testPass;
+  char testTopic[5] = "input";
+  char clientID[5] = {0x46, 0x52, 0x5a, 0x4e, 0x30 };
+  char *pClientID = clientID;
+  pGlobalSession->port = 1883; // mqtt port
   const char esp_tcp_server_ip[4] = {51, 15, 65, 206}; // remote IP of TCP server
   os_memcpy(pGlobalSession->ip, esp_tcp_server_ip, 4);
-  pGlobalSession->username = &testUser[0];
+  pGlobalSession->username_len = 11;
-  pGlobalSession->password = &testPass[0];
+  pGlobalSession->username = os_zalloc(sizeof(uint8_t) * pGlobalSession->username_len);
-  pGlobalSession->topic_name = &testTopic[0];
+  os_memcpy(pGlobalSession->username, testUser, pGlobalSession->username_len);
+  pGlobalSession->password_len = 4;
+  pGlobalSession->password = os_zalloc(sizeof(uint8_t) * pGlobalSession->password_len);
+  os_memcpy(pGlobalSession->password, testPass, pGlobalSession->password_len);
+  pGlobalSession->topic_name_len = 5;
+  pGlobalSession->topic_name = os_zalloc(sizeof(uint8_t) * pGlobalSession->topic_name_len);
+  os_memcpy(pGlobalSession->topic_name, testTopic, pGlobalSession->topic_name_len);
+  pGlobalSession->client_id_len = 5;
+  pGlobalSession->client_id = os_zalloc(sizeof(uint8_t) * pGlobalSession->client_id_len);
+  os_memcpy(pGlobalSession->client_id, clientID, pGlobalSession->client_id_len);
+  
   os_timer_setfn(&oneTimer, (os_timer_func_t *)tcpConnect, pGlobalSession);
   os_timer_arm(&oneTimer, 15000, 0);
   os_timer_setfn(&testTimer, (os_timer_func_t *)test, pGlobalSession);
-  os_timer_arm(&testTimer, 16000, 0);
+  os_timer_arm(&testTimer, 17000, 0);
 }

mqtt.h

@@ -39,10 +39,14 @@ typedef struct {
   uint32_t port;
   uint32_t localPort;
   uint8_t *client_id;
+  uint32_t client_id_len;
   uint8_t *topic_name;
+  uint32_t topic_name_len;
   uint8_t qos_level;
   uint8_t *username;
+  uint32_t username_len;
   uint8_t *password;
+  uint32_t password_len;
   char valid_connection;
   struct espconn *activeConnection;
 } mqtt_session_t;
@@ -54,4 +58,4 @@ LOCAL void ICACHE_FLASH_ATTR connected_callback(void *arg);
 LOCAL void ICACHE_FLASH_ATTR data_recv_callback(void *arg, char *pdata, unsigned short len);
 LOCAL void ICACHE_FLASH_ATTR data_sent_callback(void *arg);
 LOCAL uint8_t ICACHE_FLASH_ATTR mqtt_send(mqtt_session_t *session, uint8_t *data, uint32_t len, mqtt_message_type msgType);
-LOCAL uint8_t ICACHE_FLASH_ATTR mqtt_connect(mqtt_session_t *session);
+LOCAL uint8_t ICACHE_FLASH_ATTR mqtt_connect(mqtt_session_t *session, uint8_t *username, uint8_t *password);