#include <stdio.h>      /* for printf() and fprintf() */ 
#include <sys/socket.h> /* for socket(), bind(), and connect() */ 
#include <arpa/inet.h>  /* for sockaddr_in and inet_ntoa() */ 
#include <stdlib.h>     /* for atoi() and exit() */ 
#include <string.h>     /* for memset() */ 
#include <unistd.h>     /* for close() */ 
 
#define RCVBUFSIZE 64   /* Size of receive buffer */ 
#define MAXPENDING 5    /* Maximum outstanding connection requests */ 
 
void DieWithError(char *errorMessage);  /* Error handling function */ 
void HandleTCPClient(int clntSocket);   /* TCP client handling function */ 
 
int main(int argc, char *argv[]) 
{ 
    int servSock;                    /* Socket descriptor for server */ 
    int clntSock;                    /* Socket descriptor for client */ 
    struct sockaddr_in echoServAddr; /* Local address */ 
    struct sockaddr_in echoClntAddr; /* Client address */ 
    unsigned short echoServPort;     /* Server port */ 
    unsigned int clntLen;            /* Length of client address data structure */ 
 
    if (argc != 2)     /* Test for correct number of arguments */ 
    { 
        fprintf(stderr, "Usage:  %s <Server Port>\n", argv[0]); 
        exit(1); 
    } 
 
    echoServPort = atoi(argv[1]);  /* First arg:  local port */ 
 
    /* Create socket for incoming connections */ 
    if ((servSock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) 
        DieWithError("socket() failed"); 
       
    /* Construct local address structure */ 
    memset(&echoServAddr, 0, sizeof(echoServAddr));   /* Zero out structure */ 
    echoServAddr.sin_family = AF_INET;                /* Internet address family */ 
    echoServAddr.sin_addr.s_addr = htonl(INADDR_ANY); /* Any incoming interface */ 
    echoServAddr.sin_port = htons(echoServPort);      /* Local port */ 
 
    /* Bind to the local address */ 
    if (bind(servSock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0) 
        DieWithError("bind() failed"); 
 
    /* Mark the socket so it will listen for incoming connections */ 
    if (listen(servSock, MAXPENDING) < 0) 
        DieWithError("listen() failed"); 
 
    for (;;) /* Run forever */ 
    { 
        /* Set the size of the in-out parameter */ 
        clntLen = sizeof(echoClntAddr); 
 
        /* Wait for a client to connect */ 
        if ((clntSock = accept(servSock, (struct sockaddr *) &echoClntAddr,  
                               &clntLen)) < 0) 
            DieWithError("accept() failed"); 
 
        /* clntSock is connected to a client! */ 
 
        printf("Handling client %s\n", inet_ntoa(echoClntAddr.sin_addr)); 
 
        HandleTCPClient(clntSock); 
    } 
    /* NOT REACHED */ 
}//-- end main --// 
 
 
 
// 
//// 
// 
void DieWithError(char *errorMessage) 
{ 
    perror(errorMessage); 
    exit(1); 
} 
 
 
 
// 
//// 
// 
void HandleTCPClient(int clntSocket) 
{ 
    char echoBuffer[RCVBUFSIZE];        /* Buffer for echo string */ 
    int recvMsgSize;                    /* Size of received message */ 
 
    /* Receive message from client */ 
    if ((recvMsgSize = recv(clntSocket, echoBuffer, RCVBUFSIZE, 0)) < 0) 
        DieWithError("recv() failed"); 
 
    /* got incoming request from client in the echobuffer */ 
    recvMsgSize = sprintf(echoBuffer, 
                          "MOTOR=0,TEMPS are 3A,42,FA,99");//reply!  
 
    /* Send received string and receive again until end of transmission */ 
    while (recvMsgSize > 0)      /* zero indicates end of transmission */ 
    { 
        /* Echo message back to client */ 
        if (send(clntSocket, echoBuffer, recvMsgSize, 0) != recvMsgSize) 
            DieWithError("send() failed"); 
 
        /* See if there is more data to receive */ 
        if ((recvMsgSize = recv(clntSocket, echoBuffer, RCVBUFSIZE, 0)) < 0) 
            DieWithError("recv() failed"); 
    } 
 
    close(clntSocket);    /* Close client socket */ 
}

#include <stdio.h>      /* for printf() and fprintf() */ 
#include <sys/socket.h> /* for socket(), connect(), send(), and recv() */ 
#include <arpa/inet.h>  /* for sockaddr_in and inet_addr() */ 
#include <stdlib.h>     /* for atoi() and exit() */ 
#include <string.h>     /* for memset() */ 
#include <unistd.h>     /* for close() */ 
 
#define RCVBUFSIZE 64   /* Size of receive buffer */ 
 
void DieWithError(char *errorMessage);  /* Error handling function */ 
 
int main(int argc, char *argv[]) 
{ 
    int sock;                        /* Socket descriptor */ 
    struct sockaddr_in echoServAddr; /* Echo server address */ 
    unsigned short echoServPort;     /* Echo server port */ 
    char *servIP;                    /* Server IP address (dotted quad) */ 
    char *echoString;                /* String to send to echo server */ 
    char echoBuffer[RCVBUFSIZE];     /* Buffer for echo string */ 
    unsigned int echoStringLen;      /* Length of string to echo */ 
    int bytesRcvd, totalBytesRcvd;   /* Bytes read in single recv()  
                                        and total bytes read */ 
 
    if ((argc < 3) || (argc > 4))    /* Test for correct number of arguments */ 
    { 
       fprintf(stderr, "Usage: %s <Server IP> <Echo Word> [<Echo Port>]\n", 
               argv[0]); 
       exit(1); 
    } 
 
    servIP = argv[1];             /* First arg: server IP address (dotted quad) */ 
    echoString = argv[2];         /* Second arg: string to echo */ 
 
    if (argc == 4) 
        echoServPort = atoi(argv[3]); /* Use given port, if any */ 
    else 
        echoServPort = 7;  /* 7 is the well-known port for the echo service */ 
 
    /* Create a reliable, stream socket using TCP */ 
    if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) 
        DieWithError("socket() failed"); 
 
    /* Construct the server address structure */ 
    memset(&echoServAddr, 0, sizeof(echoServAddr));     /* Zero out structure */ 
    echoServAddr.sin_family      = AF_INET;             /* Internet address family */ 
    echoServAddr.sin_addr.s_addr = inet_addr(servIP);   /* Server IP address */ 
    echoServAddr.sin_port        = htons(echoServPort); /* Server port */ 
 
    /* Establish the connection to the echo server */ 
    if (connect(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0) 
        DieWithError("connect() failed"); 
 
    echoStringLen = strlen(echoString);          /* Determine input length */ 
 
    /* Send the string to the server */ 
    if (send(sock, echoString, echoStringLen, 0) != echoStringLen) 
        DieWithError("send() sent a different number of bytes than expected"); 
 
    /* Receive the same string back from the server */ 
    totalBytesRcvd = 0; 
    printf("Received: ");                /* Setup to print the echoed string */ 
    while (totalBytesRcvd < echoStringLen) 
    { 
        /* Receive up to the buffer size (minus 1 to leave space for 
           a null terminator) bytes from the sender */ 
        if ((bytesRcvd = recv(sock, echoBuffer, RCVBUFSIZE - 1, 0)) <= 0) 
            DieWithError("recv() failed or connection closed prematurely"); 
        totalBytesRcvd += bytesRcvd;   /* Keep tally of total bytes */ 
        echoBuffer[bytesRcvd] = '\0';  /* Terminate the string! */ 
        printf("%s", echoBuffer);      /* Print the echo buffer */ 
    } 
 
    printf("\n");    /* Print a final linefeed */ 
 
    close(sock); 
    exit(0); 
}//-- end main --// 
 
 
 
// 
//// 
// 
void DieWithError(char *errorMessage) 
{ 
    perror(errorMessage); 
    exit(1); 
}