Start on embedded MQTT-SN gateway

MQTTSNGateway/src/MQTTConnection.h

@@ -0,0 +1,559 @@
+/*******************************************************************************
+ * 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
+ *******************************************************************************/
+
+#if !defined(MQTTCONNECTION_H)
+#define MQTTCONNECTION_H
+
+#include "FP.h"
+#include "MQTTPacket.h"
+#include "stdio.h"
+#include "MQTTLogging.h"
+
+#if !defined(MQTTCLIENT_QOS1)
+    #define MQTTCLIENT_QOS1 1
+#endif
+#if !defined(MQTTCLIENT_QOS2)
+    #define MQTTCLIENT_QOS2 0
+#endif
+
+namespace MQTT
+{
+
+
+enum QoS { QOS0, QOS1, QOS2 };
+
+// all failure return codes must be negative
+enum returnCode { BUFFER_OVERFLOW = -2, FAILURE = -1, SUCCESS = 0 };
+
+
+struct Message
+{
+    enum QoS qos;
+    bool retained;
+    bool dup;
+    unsigned short id;
+    void *payload;
+    size_t payloadlen;
+};
+
+
+class PacketId
+{
+public:
+    PacketId()
+    {
+        next = 0;
+    }
+
+    int getNext()
+    {
+        return next = (next == MAX_PACKET_ID) ? 1 : ++next;
+    }
+
+private:
+    static const int MAX_PACKET_ID = 65535;
+    int next;
+};
+
+
+/**
+ * @class Client
+ * @brief blocking, non-threaded MQTT client API
+ *
+ * This version of the API blocks on all method calls, until they are complete.  This means that only one
+ * MQTT request can be in process at any one time.
+ * @param Network a network class which supports send, receive
+ * @param Timer a timer class with the methods:
+ */
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE = 100, int MAX_MESSAGE_HANDLERS = 5>
+class Connection
+{
+
+public: 
+
+    /** Construct the client
+     *  @param network - pointer to an instance of the Network class - must be connected to the endpoint
+     *      before calling MQTT connect
+     *  @param limits an instance of the Limit class - to alter limits as required
+     */
+    Connection(unsigned int command_timeout_ms = 30000);
+    
+    
+    static void run(void const* arg);
+    
+
+    /** MQTT Disconnect - send an MQTT disconnect packet, and clean up any state
+     *  @return success code -
+     */
+    int disconnect();
+
+    /** Is the client connected?
+     *  @return flag - is the client connected or not?
+     */
+    bool isConnected()
+    {
+        return isconnected;
+    }
+
+    int sendPacket(int length, Timer& timer);
+    unsigned char sendbuf[MAX_MQTT_PACKET_SIZE];
+
+private:
+
+    int connect(MQTTPacket_connectData&);
+    int connect();
+    
+    void cleanSession();
+    int cycle(Timer& timer);
+    int waitfor(int packet_type, Timer& timer);
+    int keepalive();
+    int publish(int len, Timer& timer, enum QoS qos);
+
+    int decodePacket(int* value, int timeout);
+    int readPacket(Timer& timer);
+
+    Network ipstack;
+    unsigned long command_timeout_ms;
+    unsigned char readbuf[MAX_MQTT_PACKET_SIZE];
+
+    Timer last_sent, last_received;
+    unsigned int keepAliveInterval;
+    bool ping_outstanding;
+    bool cleansession;
+
+    PacketId packetid;
+
+    bool isconnected;
+
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    unsigned char pubbuf[MAX_MQTT_PACKET_SIZE];  // store the last publish for sending on reconnect
+    int inflightLen;
+    unsigned short inflightMsgid;
+    enum QoS inflightQoS;
+#endif
+
+#if MQTTCLIENT_QOS2
+    bool pubrel;
+    #if !defined(MAX_INCOMING_QOS2_MESSAGES)
+        #define MAX_INCOMING_QOS2_MESSAGES 10
+    #endif
+    unsigned short incomingQoS2messages[MAX_INCOMING_QOS2_MESSAGES];
+    bool isQoS2msgidFree(unsigned short id);
+    bool useQoS2msgid(unsigned short id);
+    void freeQoS2msgid(unsigned short id);
+#endif
+
+};
+
+}
+
+
+template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
+void MQTT::Connection<Network, Timer, a, MAX_MESSAGE_HANDLERS>::run(void const* arg)
+{
+    
+    
+    
+        
+}
+
+
+template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
+void MQTT::Connection<Network, Timer, a, MAX_MESSAGE_HANDLERS>::cleanSession() 
+{
+    ping_outstanding = false;
+    isconnected = false;
+
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    inflightMsgid = 0;
+    inflightQoS = QOS0;
+#endif
+
+#if MQTTCLIENT_QOS2
+    pubrel = false;
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+        incomingQoS2messages[i] = 0;
+#endif
+}
+
+
+template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
+MQTT::Connection<Network, Timer, a, MAX_MESSAGE_HANDLERS>::Connection(unsigned int command_timeout_ms) : packetid()
+{
+    last_sent = Timer();
+    last_received = Timer();
+    this->command_timeout_ms = command_timeout_ms;
+    cleanSession();
+}
+
+
+#if MQTTCLIENT_QOS2
+template<class Network, class Timer, int a, int b>
+bool MQTT::Connection<Network, Timer, a, b>::isQoS2msgidFree(unsigned short id)
+{
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+    {
+        if (incomingQoS2messages[i] == id)
+            return false;
+    }
+    return true;
+}
+
+
+template<class Network, class Timer, int a, int b>
+bool MQTT::Connection<Network, Timer, a, b>::useQoS2msgid(unsigned short id)
+{
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+    {
+        if (incomingQoS2messages[i] == 0)
+        {
+            incomingQoS2messages[i] = id;
+            return true;
+        }
+    }
+    return false;
+}
+
+
+template<class Network, class Timer, int a, int b>
+void MQTT::Connection<Network, Timer, a, b>::freeQoS2msgid(unsigned short id)
+{
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+    {
+        if (incomingQoS2messages[i] == id)
+        {
+            incomingQoS2messages[i] = 0;
+            return;
+        }
+    }
+}
+#endif
+
+
+template<class Network, class Timer, int a, int b>
+int MQTT::Connection<Network, Timer, a, b>::sendPacket(int length, Timer& timer)
+{
+    int rc = FAILURE,
+        sent = 0;
+
+    while (sent < length && !timer.expired())
+    {
+        rc = ipstack.write(&sendbuf[sent], length - sent, timer.left_ms());
+        if (rc < 0)  // there was an error writing the data
+            break;
+        sent += rc;
+    }
+    if (sent == length)
+    {
+        if (this->keepAliveInterval > 0)
+            last_sent.countdown(this->keepAliveInterval); // record the fact that we have successfully sent the packet
+        rc = SUCCESS;
+    }
+    else
+        rc = FAILURE;
+        
+#if defined(MQTT_DEBUG)
+    char printbuf[150];
+    DEBUG("Rc %d from sending packet %s\n", rc, MQTTFormat_toServerString(printbuf, sizeof(printbuf), sendbuf, length));
+#endif
+    return rc;
+}
+
+
+template<class Network, class Timer, int a, int b>
+int MQTT::Connection<Network, Timer, a, b>::decodePacket(int* value, int timeout)
+{
+    unsigned char c;
+    int multiplier = 1;
+    int len = 0;
+    const int MAX_NO_OF_REMAINING_LENGTH_BYTES = 4;
+
+    *value = 0;
+    do
+    {
+        int rc = MQTTPACKET_READ_ERROR;
+
+        if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES)
+        {
+            rc = MQTTPACKET_READ_ERROR; /* bad data */
+            goto exit;
+        }
+        rc = ipstack.read(&c, 1, timeout);
+        if (rc != 1)
+            goto exit;
+        *value += (c & 127) * multiplier;
+        multiplier *= 128;
+    } while ((c & 128) != 0);
+exit:
+    return len;
+}
+
+
+/**
+ * If any read fails in this method, then we should disconnect from the network, as on reconnect
+ * the packets can be retried.
+ * @param timeout the max time to wait for the packet read to complete, in milliseconds
+ * @return the MQTT packet type, or -1 if none
+ */
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Connection<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::readPacket(Timer& timer)
+{
+    int rc = FAILURE;
+    MQTTHeader header = {0};
+    int len = 0;
+    int rem_len = 0;
+
+    /* 1. read the header byte.  This has the packet type in it */
+    if (ipstack.read(readbuf, 1, timer.left_ms()) != 1)
+        goto exit;
+
+    len = 1;
+    /* 2. read the remaining length.  This is variable in itself */
+    decodePacket(&rem_len, timer.left_ms());
+    len += MQTTPacket_encode(readbuf + 1, rem_len); /* put the original remaining length into the buffer */
+
+    if (rem_len > (MAX_MQTT_PACKET_SIZE - len))
+    {
+        rc = BUFFER_OVERFLOW;
+        goto exit;
+    }
+
+    /* 3. read the rest of the buffer using a callback to supply the rest of the data */
+    if (rem_len > 0 && (ipstack.read(readbuf + len, rem_len, timer.left_ms()) != rem_len))
+        goto exit;
+
+    header.byte = readbuf[0];
+    rc = header.bits.type;
+    if (this->keepAliveInterval > 0)
+        last_received.countdown(this->keepAliveInterval); // record the fact that we have successfully received a packet
+exit:
+        
+#if defined(MQTT_DEBUG)
+    if (rc >= 0)
+    {
+        char printbuf[50];
+        DEBUG("Rc %d from receiving packet %s\n", rc, MQTTFormat_toClientString(printbuf, sizeof(printbuf), readbuf, len));
+    }
+#endif
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Connection<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::cycle(Timer& timer)
+{
+    /* get one piece of work off the wire and one pass through */
+
+    // read the socket, see what work is due
+    int packet_type = readPacket(timer);
+
+    int len = 0,
+        rc = SUCCESS;
+
+    switch (packet_type)
+    {
+        case FAILURE:
+        case BUFFER_OVERFLOW:
+            rc = packet_type;
+            break;
+        case CONNACK:
+        case PUBACK:
+        case SUBACK:
+            break;
+        case PUBLISH:
+        {
+            MQTTString topicName = MQTTString_initializer;
+            Message msg;
+            int intQoS;
+            if (MQTTDeserialize_publish((unsigned char*)&msg.dup, &intQoS, (unsigned char*)&msg.retained, (unsigned short*)&msg.id, &topicName,
+                                 (unsigned char**)&msg.payload, (int*)&msg.payloadlen, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
+                goto exit;
+            msg.qos = (enum QoS)intQoS;
+#if MQTTCLIENT_QOS2
+            if (msg.qos != QOS2)
+#endif
+                ; //deliverMessage(topicName, msg);
+#if MQTTCLIENT_QOS2
+            else if (isQoS2msgidFree(msg.id))
+            {
+                if (useQoS2msgid(msg.id))
+                    ; //deliverMessage(topicName, msg);
+                else
+                    WARN("Maximum number of incoming QoS2 messages exceeded");
+            }
+#endif
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+            if (msg.qos != QOS0)
+            {
+                if (msg.qos == QOS1)
+                    len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBACK, 0, msg.id);
+                else if (msg.qos == QOS2)
+                    len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBREC, 0, msg.id);
+                if (len <= 0)
+                    rc = FAILURE;
+                else
+                    rc = sendPacket(len, timer);
+                if (rc == FAILURE)
+                    goto exit; // there was a problem
+            }
+            break;
+#endif
+        }
+#if MQTTCLIENT_QOS2
+        case PUBREC:
+        case PUBREL:
+            unsigned short mypacketid;
+            unsigned char dup, type;
+            if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
+                rc = FAILURE;
+            else if ((len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, 
+                        (packet_type == PUBREC) ? PUBREL : PUBCOMP, 0, mypacketid)) <= 0)
+                rc = FAILURE;
+            else if ((rc = sendPacket(len, timer)) != SUCCESS) // send the PUBREL packet
+                rc = FAILURE; // there was a problem
+            if (rc == FAILURE)
+                goto exit; // there was a problem
+            if (packet_type == PUBREL)
+                freeQoS2msgid(mypacketid);
+            break;
+            
+        case PUBCOMP:
+            break;
+#endif
+        case PINGRESP:
+            ping_outstanding = false;
+            break;
+    }
+    keepalive();
+exit:
+    if (rc == SUCCESS)
+        rc = packet_type;
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Connection<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::keepalive()
+{
+    int rc = FAILURE;
+
+    if (keepAliveInterval == 0)
+    {
+        rc = SUCCESS;
+        goto exit;
+    }
+
+    if (last_sent.expired() || last_received.expired())
+    {
+        if (!ping_outstanding)
+        {
+            Timer timer(1000);
+            int len = MQTTSerialize_pingreq(sendbuf, MAX_MQTT_PACKET_SIZE);
+            if (len > 0 && (rc = sendPacket(len, timer)) == SUCCESS) // send the ping packet
+                ping_outstanding = true;
+        }
+    }
+
+exit:
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Connection<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::connect(MQTTPacket_connectData& options)
+{
+    Timer connect_timer(command_timeout_ms);
+    int rc = FAILURE;
+    int len = 0;
+
+    if (isconnected) // don't send connect packet again if we are already connected
+        goto exit;
+
+    this->keepAliveInterval = options.keepAliveInterval;
+    this->cleansession = options.cleansession;
+    if ((len = MQTTSerialize_connect(sendbuf, MAX_MQTT_PACKET_SIZE, &options)) <= 0)
+        goto exit;
+    if ((rc = sendPacket(len, connect_timer)) != SUCCESS)  // send the connect packet
+        goto exit; // there was a problem
+
+    if (this->keepAliveInterval > 0)
+        last_received.countdown(this->keepAliveInterval);
+    // this will be a blocking call, wait for the connack
+    if (waitfor(CONNACK, connect_timer) == CONNACK)
+    {
+        unsigned char connack_rc = 255;
+        bool sessionPresent = false;
+        if (MQTTDeserialize_connack((unsigned char*)&sessionPresent, &connack_rc, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
+            rc = connack_rc;
+        else
+            rc = FAILURE;
+    }
+    else
+        rc = FAILURE;
+
+#if MQTTCLIENT_QOS2
+    // resend any inflight publish
+    if (inflightMsgid > 0 && inflightQoS == QOS2 && pubrel)
+    {
+        if ((len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBREL, 0, inflightMsgid)) <= 0)
+            rc = FAILURE;
+        else
+            rc = publish(len, connect_timer, inflightQoS);
+    }
+    else
+#endif
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    if (inflightMsgid > 0)
+    {
+        memcpy(sendbuf, pubbuf, MAX_MQTT_PACKET_SIZE);
+        rc = publish(inflightLen, connect_timer, inflightQoS);
+    }
+#endif
+
+exit:
+    if (rc == SUCCESS)
+        isconnected = true;
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Connection<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::connect()
+{
+    MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer;
+    return connect(default_options);
+}
+
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Connection<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::disconnect()
+{
+    int rc = FAILURE;
+    Timer timer(command_timeout_ms);            // we might wait for incomplete incoming publishes to complete
+    int len = MQTTSerialize_disconnect(sendbuf, MAX_MQTT_PACKET_SIZE);
+    if (len > 0)
+        rc = sendPacket(len, timer);            // send the disconnect packet
+
+    if (cleansession)
+        cleanSession();
+    else
+        isconnected = false;
+    return rc;
+}
+
+
+#endif

MQTTSNGateway/src/MQTTSNGateway.h

@@ -0,0 +1,296 @@
+/*******************************************************************************
+ * 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
+ *******************************************************************************/
+
+#if !defined(MQTTSNGATEWAY_H)
+#define MQTTSNGATEWAY_H
+
+#include "MQTTSNPacket.h"
+#include "MQTTConnection.h"
+
+namespace MQTTSN
+{
+ 
+#define MAX_PACKET_SIZE 256   
+#define MQTTSNGATEWAY_QOS2 0 
+#define MQTTSNGATEWAY_QOS1 0
+#define MAX_MQTT_CONNECTIONS 5
+    
+struct Parms
+{
+  char* hostname;
+  int port;
+  char* username;
+  char* password;  
+};
+
+enum QoS { QOS0, QOS1, QOS2 };
+
+enum Modes { AGGREGATING, TRANSPARENT };
+
+// all failure return codes must be negative
+enum returnCode { MAX_SUBSCRIPTIONS_EXCEEDED = -3, BUFFER_OVERFLOW = -2, FAILURE = -1, SUCCESS = 0 };
+
+struct Message
+{
+    enum QoS qos;
+    bool retained;
+    bool dup;
+    unsigned short id;
+    void *payload;
+    size_t payloadlen;
+};
+
+
+template<class UDPNetwork, class TCPNetwork, class Timer, class Thread, class Mutex>
+class Gateway
+{
+public:
+
+    Gateway(UDPNetwork&, unsigned int command_timeout_ms = 30000);
+
+    void run(void const* arg);
+    
+private:
+
+    int cycle(Timer& timer);
+    int sendPacket(int length, Timer& timer);
+    int readPacket(Timer& timer);
+    
+    UDPNetwork& udpstack;  // Not restricted to UDP -  for want of a better name
+    
+    unsigned char sendbuf[MAX_PACKET_SIZE];
+    unsigned char readbuf[MAX_PACKET_SIZE];
+    
+    enum Modes mode;
+    
+    MQTT::Connection<TCPNetwork, Timer> connections[MAX_MQTT_CONNECTIONS];
+
+};
+
+
+} // end namespace
+
+
+template<class UDPNetwork, class TCPNetwork, class Timer, class Thread, class Mutex>
+MQTTSN::Gateway<UDPNetwork, TCPNetwork, Timer, Thread, Mutex>::Gateway(UDPNetwork& network, unsigned int command_timeout_ms) : udpstack(network)
+{
+    mode = AGGREGATING;
+}
+
+
+template<class UDPNetwork, class TCPNetwork, class Timer, class Thread, class Mutex>
+void MQTTSN::Gateway<UDPNetwork, TCPNetwork, Timer, Thread, Mutex>::run(void const* arg)
+{   
+    Timer timer;
+    
+    printf("Gateway run 0\n");
+    if (mode == AGGREGATING)
+    {
+        // set up connection 0 information
+        Thread mythread(&connections[0].run); 
+    }
+    
+    printf("Gateway run 1\n");
+    while (true)
+    {
+     		printf("Gateway cycle\n");
+        cycle(timer);
+    }
+    
+}
+
+
+template<class UDPNetwork, class TCPNetwork, class Timer, class Thread, class Mutex>
+int MQTTSN::Gateway<UDPNetwork, TCPNetwork, Timer, Thread, Mutex>::cycle(Timer& timer)
+{
+    /* get one piece of work off the wire and one pass through */
+
+    // read the socket, see what work is due
+    unsigned short packet_type = readPacket(timer);
+    
+    printf("read packet\n");
+
+    int len = 0;
+    int rc = SUCCESS;
+
+    switch (packet_type)
+    {
+        case MQTTSN_CONNECT:
+        {
+            MQTTSNPacket_connectData data = MQTTSNPacket_connectData_initializer;
+            MQTTSNDeserialize_connect(&data, readbuf, MAX_PACKET_SIZE);
+            
+            if (mode == TRANSPARENT)
+            {
+                //start a new MQTT connection at this point
+            }
+            
+            len = MQTTSNSerialize_connack(sendbuf, MAX_PACKET_SIZE, 0);
+            if (len <= 0)
+                rc = FAILURE;
+            else
+                rc = sendPacket(len, timer);
+            break;
+        }   
+        
+        case MQTTSN_REGISTER:
+        {
+            unsigned short topicid, packetid;
+            MQTTSNString topicName;
+            unsigned char reg_rc = MQTTSN_RC_ACCEPTED;
+            if (MQTTSNDeserialize_register(&topicid, &packetid, &topicName, readbuf, MAX_PACKET_SIZE) != 1)
+                goto exit;
+                
+            // store topic registration info    
+                
+            len = MQTTSNSerialize_regack(connections[0].sendbuf, MAX_PACKET_SIZE, topicid, packetid, reg_rc);
+            if (len <= 0)
+                rc = FAILURE;
+            else
+                rc = connections[0].sendPacket(len, timer);
+                
+            break;
+        }
+        
+        case MQTTSN_SUBSCRIBE:
+        {
+            unsigned char dup;
+            int qos;
+            unsigned short packetid;
+            MQTTSN_topicid topicFilter;
+            MQTTSNDeserialize_subscribe(&dup, &qos, &packetid, &topicFilter, readbuf, MAX_PACKET_SIZE);
+            MQTTString topic = MQTTString_initializer;
+            
+            if (topicFilter.type == MQTTSN_TOPIC_TYPE_NORMAL)
+            {
+                topic.lenstring.len = topicFilter.data.long_.len;
+                topic.lenstring.data = topicFilter.data.long_.name;
+            }
+            
+            len = MQTTSerialize_subscribe(connections[0].sendbuf, MAX_PACKET_SIZE, 0, packetid, 1, &topic, (int*)&qos);
+            if (len <= 0)
+                goto exit;
+            if ((rc = connections[0].sendPacket(len, timer)) != SUCCESS) // send the subscribe packet
+                goto exit;             // there was a problem
+            
+            break;
+        }
+        
+        case MQTTSN_PUBLISH:
+        {
+            MQTTString topic = MQTTString_initializer;
+            MQTTSN_topicid topicid;
+            Message msg;
+            
+            if (MQTTSNDeserialize_publish((unsigned char*)&msg.dup, (int*)&msg.qos, (unsigned char*)&msg.retained, &msg.id, &topicid,
+                                 (unsigned char**)&msg.payload, (int*)&msg.payloadlen, readbuf, MAX_PACKET_SIZE) != 1)
+                goto exit;
+            
+                
+            len = MQTTSerialize_publish(connections[0].sendbuf, MAX_PACKET_SIZE, msg.dup, msg.qos, msg.retained, msg.id, topic, 
+                                (unsigned char*)msg.payload, msg.payloadlen);
+            if (len <= 0)
+                goto exit;
+            if ((rc = connections[0].sendPacket(len, timer)) != SUCCESS) // send the subscribe packet
+                goto exit;             // there was a problem
+                
+        } 
+                
+                
+        case MQTTSN_PINGRESP:
+            //ping_outstanding = false;
+            break;
+    }
+    //keepalive();
+exit:
+    if (rc == SUCCESS)
+        rc = packet_type;
+    return rc;
+}
+
+
+
+template<class UDPNetwork, class TCPNetwork, class Timer, class Thread, class Mutex>
+int MQTTSN::Gateway<UDPNetwork, TCPNetwork, Timer, Thread, Mutex>::sendPacket(int length, Timer& timer)
+{
+    int rc = FAILURE,
+        sent = 0;
+
+    do
+    {
+        sent = udpstack.write(sendbuf, length, timer.left_ms());
+        printf("sendPacket, rc %d from write of %d bytes\n", sent, length);
+        if (sent < 0)  // there was an error writing the data
+            break;
+    }
+    while (sent != length && !timer.expired());
+    
+    if (sent == length)
+    {
+        //if (this->duration > 0)
+        //    last_sent.countdown(this->duration); // record the fact that we have successfully sent the packet
+        rc = SUCCESS;
+    }
+    else
+        rc = FAILURE;
+        
+#if defined(MQTT_DEBUG)
+    char printbuf[50];
+    DEBUG("Rc %d from sending packet %s\n", rc, MQTTSNPacket_toString(printbuf, sizeof(printbuf), sendbuf, length));
+#endif
+    return rc;
+}
+
+
+/**
+ * If any read fails in this method, then we should disconnect from the network, as on reconnect
+ * the packets can be retried.
+ * @param timeout the max time to wait for the packet read to complete, in milliseconds
+ * @return the MQTT packet type, or -1 if none
+ */
+template<class UDPNetwork, class TCPNetwork, class Timer, class Thread, class Mutex>
+int MQTTSN::Gateway<UDPNetwork, TCPNetwork, Timer, Thread, Mutex>::readPacket(Timer& timer)
+{
+    int rc = FAILURE;
+    int len = 0;  // the length of the whole packet including length field 
+    int lenlen = 0;
+    int datalen = 0;
+
+    #define MQTTSN_MIN_PACKET_LENGTH 3
+    // 1. read the packet, datagram style 
+    if ((len = udpstack.read(readbuf, MAX_PACKET_SIZE, timer.left_ms())) < MQTTSN_MIN_PACKET_LENGTH)
+        goto exit;
+        
+    // 2. read the length.  This is variable in itself 
+    lenlen = MQTTSNPacket_decode(readbuf, len, &datalen);
+    if (datalen != len)
+        goto exit; // there was an error 
+        
+    rc = readbuf[lenlen];
+    //if (this->duration > 0)
+    //    last_received.countdown(this->duration); // record the fact that we have successfully received a packet
+exit:
+        
+#if defined(MQTT_DEBUG)
+    char printbuf[50];
+    DEBUG("Rc %d from receiving packet %s\n", rc, MQTTSNPacket_toString(printbuf, sizeof(printbuf), readbuf, len));
+#endif
+    return rc;
+}
+
+
+
+#endif

MQTTSNGateway/src/linux/Threading.h

@@ -0,0 +1,36 @@
+
+
+extern "C"
+{
+	#include "Thread.h"
+}
+
+
+class Thread
+{
+
+/*
+Thread(void (*fn)(void const *argument), void *argument)
+{
+	Thread_start(fn, arg);
+}*/
+
+public:
+
+	Thread(void (*fn)(void const *argument))
+	{
+		const void* arg = NULL;
+	
+		//Thread_start((void (*)(void *))fn, arg);
+	}
+
+};
+
+
+
+
+class Mutex
+{
+
+
+};

MQTTSNGateway/src/linux/build.sh

@@ -0,0 +1,2 @@
+g++ main.cpp -I MQTTPacket/src -I MQTTSNPacket/src -I linux MQTTPacket/src/*.c MQTTSNPacket/src/*.c
+ 

MQTTSNGateway/src/linux/linux.cpp

@@ -0,0 +1,224 @@
+/*******************************************************************************
+ * Copyright (c) 2014, 2015 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 <sys/types.h>
+#include <sys/socket.h>
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/select.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+
+
+class IPStack 
+{
+public:    
+    IPStack()
+    {
+
+    }
+    
+	int Socket_error(const char* aString)
+	{
+		int rc = 0;
+		//if (errno != EINTR && errno != EAGAIN && errno != EINPROGRESS && errno != EWOULDBLOCK)
+		//{
+			if (strcmp(aString, "shutdown") != 0 || (errno != ENOTCONN && errno != ECONNRESET))
+			{
+				if (errno != EINTR && errno != EAGAIN && errno != EINPROGRESS && errno != EWOULDBLOCK)
+				printf("Socket error %s in %s for socket %d\n", strerror(errno), aString, mysock);
+				rc = errno;
+			}
+		//}
+		return errno;
+	}
+
+    int connect(const char* hostname, int port)
+    {
+		int type = SOCK_STREAM;
+		struct sockaddr_in address;
+		int rc = -1;
+		sa_family_t family = AF_INET;
+		struct addrinfo *result = NULL;
+		struct addrinfo hints = {0, AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, 0, NULL, NULL, NULL};
+
+		if ((rc = getaddrinfo(hostname, NULL, &hints, &result)) == 0)
+		{
+			struct addrinfo* res = result;
+
+			/* prefer ip4 addresses */
+			while (res)
+			{
+				if (res->ai_family == AF_INET)
+				{
+					result = res;
+					break;
+				}
+				res = res->ai_next;
+			}
+
+			if (result->ai_family == AF_INET)
+			{
+				address.sin_port = htons(port);
+				address.sin_family = family = AF_INET;
+				address.sin_addr = ((struct sockaddr_in*)(result->ai_addr))->sin_addr;
+			}
+			else
+				rc = -1;
+
+			freeaddrinfo(result);
+		}
+
+		if (rc == 0)
+		{
+			mysock = socket(family, type, 0);
+			if (mysock != -1)
+			{
+				int opt = 1;
+
+				//if (setsockopt(mysock, SOL_SOCKET, SO_NOSIGPIPE, (void*)&opt, sizeof(opt)) != 0)
+				//	printf("Could not set SO_NOSIGPIPE for socket %d", mysock);
+				
+				rc = ::connect(mysock, (struct sockaddr*)&address, sizeof(address));
+			}
+		}
+
+        return rc;
+    }
+
+    int read(unsigned char* buffer, int len, int timeout_ms)
+    {
+		struct timeval interval = {timeout_ms / 1000, (timeout_ms % 1000) * 1000};
+		if (interval.tv_sec < 0 || (interval.tv_sec == 0 && interval.tv_usec <= 0))
+		{
+			interval.tv_sec = 0;
+			interval.tv_usec = 100;
+		}
+
+		setsockopt(mysock, SOL_SOCKET, SO_RCVTIMEO, (char *)&interval, sizeof(struct timeval));
+
+		int bytes = 0;
+		while (bytes < len)
+		{
+			int rc = ::recv(mysock, &buffer[bytes], (size_t)(len - bytes), 0);
+			if (rc == -1)
+			{
+				if (Socket_error("read") != 0)
+				{
+					bytes = -1;
+					break;
+				}
+			}
+			else
+				bytes += rc;
+		}
+		return bytes;
+    }
+    
+    int write(unsigned char* buffer, int len, int timeout)
+    {
+		struct timeval tv;
+
+		tv.tv_sec = 0;  /* 30 Secs Timeout */
+		tv.tv_usec = timeout * 1000;  // Not init'ing this can cause strange errors
+
+		setsockopt(mysock, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,sizeof(struct timeval));
+		int	rc = ::write(mysock, buffer, len);
+		//printf("write rc %d\n", rc);
+		return rc;
+    }
+
+	int disconnect()
+	{
+		return ::close(mysock);
+	}
+    
+private:
+
+    int mysock; 
+    
+};
+
+
+class Countdown
+{
+public:
+    Countdown()
+    { 
+	
+    }
+
+    Countdown(int ms)
+    { 
+		countdown_ms(ms);
+    }
+    
+
+    bool expired()
+    {
+		struct timeval now, res;
+		gettimeofday(&now, NULL);
+		timersub(&end_time, &now, &res);		
+		//printf("left %d ms\n", (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000);
+		//if (res.tv_sec > 0 || res.tv_usec > 0)
+		//	printf("expired %d %d\n", res.tv_sec, res.tv_usec);
+        return res.tv_sec < 0 || (res.tv_sec == 0 && res.tv_usec <= 0);
+    }
+    
+
+    void countdown_ms(int ms)  
+    {
+		struct timeval now;
+		gettimeofday(&now, NULL);
+		struct timeval interval = {ms / 1000, (ms % 1000) * 1000};
+		//printf("interval %d %d\n", interval.tv_sec, interval.tv_usec);
+		timeradd(&now, &interval, &end_time);
+    }
+
+    
+    void countdown(int seconds)
+    {
+		struct timeval now;
+		gettimeofday(&now, NULL);
+		struct timeval interval = {seconds, 0};
+		timeradd(&now, &interval, &end_time);
+    }
+
+    
+    int left_ms()
+    {
+		struct timeval now, res;
+		gettimeofday(&now, NULL);
+		timersub(&end_time, &now, &res);
+		//printf("left %d ms\n", (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000);
+        return (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000;
+    }
+    
+private:
+
+	struct timeval end_time;
+};
+

MQTTSNGateway/src/linux/main.cpp

@@ -0,0 +1,24 @@
+
+#include "Threading.h"
+
+//#include "MQTTSNUDP.h"
+//#include "MQTTEthernet.h"
+#include "linux.cpp"
+#include "MQTTSNGateway.h"
+
+MQTTSN::Parms parms();
+
+
+int main()
+{
+    // set up MQTT-SN network listening
+    UDPStack net;
+    net.listen(1884);
+    
+    MQTTSN::Gateway<UDPStack, IPStack, Countdown, Thread, Mutex> gateway = 
+    			MQTTSN::Gateway<UDPStack, IPStack, Countdown, Thread, Mutex>(net);
+    
+    gateway.run(NULL);
+    
+    return 0;
+}

MQTTSNGateway/src/main.cpp

@@ -0,0 +1,33 @@
+/*
+ * main.cpp
+ *
+ *  Created on: Jan 5, 2016
+ *      Author: icraggs
+ */
+
+
+void read_config()
+{
+
+}
+
+
+
+int main(int argc, char* argv[])
+{
+
+
+	// 1. listen for MQTT-SN connections
+
+	// 2. connect to MQTT broker
+
+	// 3. listen for MQTT-SN packets, and act on them
+	// 4. listen for MQTT packets too, and act on them
+
+
+
+
+
+	return 0;
+}
+