[EasyConnect] Using Ethernet
[EasyConnect] Connected to Network successfully
[EasyConnect] IP address 192.168.0.102
Connecting to 192.168.0.101:1883
Connected!
Topic   : mbed-sample
Username: theuy
Password: theuy_mqtt
Waiting for client.yield(100) to time-out after about 90 seconds...
Message arrived: qos 0, retained 0, dup 0, packetid 57004
Payload: Hello World! (QoS0)
Arrived count: 1
QOS0: arrivedcount: 1
Failed: rc from unsubscribe was -1
Failed: rc from disconnect was -1
Finish 1 msgs

$ mosquitto_sub -v -t "mbed-sample" -u "user" -P "passwd"
mbed-sample Hello World! (QoS0)

/*******************************************************************************
 * 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
 *    Ian Craggs - make sure QoS2 processing works, and add device headers
 *******************************************************************************/

 /**
  This is a sample program to illustrate the use of the MQTT Client library
  on the mbed platform.  The Client class requires two classes which mediate
  access to system interfaces for networking and timing.  As long as these two
  classes provide the required public programming interfaces, it does not matter
  what facilities they use underneath. In this program, they use the mbed
  system libraries.

 */

//#define MQTTCLIENT_QOS2 1
#define BAUD_RATE       230400

#include "easy-connect.h"
#include "MQTTNetwork.h"
#include "MQTTmbed.h"
#include "MQTTClient.h"

int arrivedcount = 0;

Serial      pc(USBTX, USBRX);

void messageArrived(MQTT::MessageData& md)
{
    MQTT::Message &message = md.message;
    printf("Message arrived: qos %d, retained %d, dup %d, packetid %d\n", message.qos, message.retained, message.dup, message.id);
    printf("Payload: %.*s\n", message.payloadlen, (char*)message.payload);
    arrivedcount++;
    printf("Arrived count: %d\n", arrivedcount);
}

int main(int argc, char* argv[])
{
    pc.baud(BAUD_RATE);

    printf("\n");
    printf("---------------------------\n");
    printf("Starting HelloMQTT\n");
    printf("---------------------------\n");

    NetworkInterface* network = easy_connect(true);
    if (!network) {
        return -1;
    }

    MQTTNetwork mqttNetwork(network);

    MQTT::Client<MQTTNetwork, Countdown> client(mqttNetwork);

    // Connection details
//    const char* hostname = "m2m.eclipse.org";
    const char* hostname = "192.168.0.101";
    int port = 1883;
    
    printf("Connecting to %s:%d\n", hostname, port);
    
    int rc = mqttNetwork.connect(hostname, port);
    if (rc != 0) {
        printf("rc from TCP connect is %d\n", rc);
    }
    else {
        printf("Connected!\n");
    }

    MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
    data.MQTTVersion = 3;
    
    // MQTT Username, Password
    data.clientID.cstring = "mbed-sampl-nothing?";
    data.username.cstring = "user";
    data.password.cstring = "passwd";

    // MQTT Topic
    char* topic = "mbed-sample";

    printf("Topic   : %s\n", topic);
    printf("Username: %s\n", data.username.cstring);
    printf("Password: %s\n", data.password.cstring);
    
    if ((rc = client.connect(data)) != 0) {
        printf("Failed: rc from MQTT connect is %d\n", rc);
    }
    if ((rc = client.subscribe(topic, MQTT::QOS2, messageArrived)) != 0) {
        printf("Failed: rc from MQTT subscribe is %d\n", rc);
    }

    MQTT::Message message;

    // QoS 0
    char buf[100];
    sprintf(buf, "Hello World! (QoS0)");
    message.qos = MQTT::QOS0;
    message.retained = false;
    message.dup = false;
    message.payload = (void*)buf;
    message.payloadlen = strlen(buf)+1;
    rc = client.publish(topic, message);
    while (arrivedcount < 1) {
        printf("Waiting for client.yield(100) to time-out after about 90 seconds...\n");
        client.yield(100);  // Times out after about 90 seconds
        printf("QOS0: arrivedcount: %d\n", arrivedcount);
    }

    if ((rc = client.unsubscribe(topic)) != 0) {
        printf("Failed: rc from unsubscribe was %d\n", rc);
    }
    if ((rc = client.disconnect()) != 0) {
        printf("Failed: rc from disconnect was %d\n", rc);
    }

    mqttNetwork.disconnect();

    printf("Finish %d msgs\n", arrivedcount);

    return 0;
}

MQTTSocket.h

Change this 
int read(unsigned char* buffer, int len, int timeout) 
{ 
    return mysock.recv((char*)buffer, len); 
}

To this
int read(unsigned char* buffer, int len, int timeout)
{
        mysock.set_timeout(timeout);
        int rc = mysock.recv((char*)buffer, len);
        mysock.set_timeout(0);
        return rc;
}