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I'm writing a tcp server and client program in C on linux. It compiles and works under linux, but when I try to compile it using terminal under mac I get errors. If somebody knows why I would appreciate telling me. Any way I have most of the program done, but I need help with a few things that I don't know how to do. I need to do the following:

The client establishes a TCP connection and sends a message containing a file name “Data10MB.dat” to the server.
The server receives the message and sends the file “Data10MB.dat” of 10 Mbytes to the client.
The client receives the file and saves it on its local disk.
The client closes its connection to the server.

I need the program just to create a 10MB file and do those things. I don't know how to go about doing this. I would appreciate any help possible.

Sincerely yours;
jdm


server:

/* server.c - code for example server program that uses TCP */
#ifndef unix
#define WIN32
#include <windows.h>
#include <winsock.h> 
#else
#define closesocket close
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <stdio.h>
#endif

#include <stdio.h>
#include <string.h>

#define PROTOPORT       5193            /* default protocol port number */
#define QLEN            6               /* size of request queue        */

int     visits      =   0;              /* counts client connections    */
/*------------------------------------------------------------------------
 * Program:   server
 *
 * Purpose:   allocate a socket and then repeatedly execute the following:
 *              (1) wait for the next connection from a client
 *              (2) send a short message to the client
 *              (3) close the connection
 *              (4) go back to step (1)
 *
 * Syntax:    server [ port ]
 *
 *               port  - protocol port number to use
 *
 * Note:      The port argument is optional.  If no port is specified,
 *            the server uses the default given by PROTOPORT.
 *
 *------------------------------------------------------------------------
 */
main(argc, argv)
int     argc;
char    *argv[];
{
        struct  hostent  *ptrh;  /* pointer to a host table entry       */
        struct  protoent *ptrp;  /* pointer to a protocol table entry   */
        struct  sockaddr_in sad; /* structure to hold server's address  */
        struct  sockaddr_in cad; /* structure to hold client's address  */
        int     sd, sd2;         /* socket descriptors                  */
        int     port;            /* protocol port number                */
        int     alen;            /* length of address                   */
        char    buf[1000];       /* buffer for string the server sends  */

#ifdef WIN32
        WSADATA wsaData;
        WSAStartup(0x0101, &wsaData);
#endif
        memset((char *)&sad,0,sizeof(sad)); /* clear sockaddr structure */
        sad.sin_family = AF_INET;         /* set family to Internet     */
        sad.sin_addr.s_addr = INADDR_ANY; /* set the local IP address   */

        /* Check command-line argument for protocol port and extract    */
        /* port number if one is specified.  Otherwise, use the default */
        /* port value given by constant PROTOPORT                       */

        if (argc > 1) {                 /* if argument specified        */
                port = atoi(argv[1]);   /* convert argument to binary   */
        } else {
                port = PROTOPORT;       /* use default port number      */
        }
        if (port > 0)                   /* test for illegal value       */
                sad.sin_port = htons((u_short)port);
        else {                          /* print error message and exit */
                fprintf(stderr,"bad port number %s\n",argv[1]);
                exit(1);
        }

        /* Map TCP transport protocol name to protocol number */

        if ( ((int)(ptrp = getprotobyname("tcp"))) == 0) {
                fprintf(stderr, "cannot map \"tcp\" to protocol number");
                exit(1);
        }

        /* Create a socket */

        sd = socket(PF_INET, SOCK_STREAM, ptrp->p_proto);
        if (sd < 0) {
                fprintf(stderr, "socket creation failed\n");
                exit(1);
        }

        /* Bind a local address to the socket */

        if (bind(sd, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
                fprintf(stderr,"bind failed\n");
                exit(1);
        }

        /* Specify size of request queue */

        if (listen(sd, QLEN) < 0) {
                fprintf(stderr,"listen failed\n");
                exit(1);
        }

        /* Main server loop - accept and handle requests */

        while (1) {
                alen = sizeof(cad);
		printf("\nI'm waiting for connections ...\n");
		fflush(stdout);
                if ( (sd2=accept(sd, (struct sockaddr *)&cad, &alen)) < 0) {
                        fprintf(stderr, "accept failed\n");
                        exit(1);
                }
		printf("\nI received one connection.\n");
		fflush(stdout);
                visits++;
                sprintf(buf,"This server has been contacted %d time%s\n",
                        visits,visits==1?".":"s.");
                send(sd2,buf,strlen(buf),0);
		printf("\nI sent the client a string.\n");
		fflush(stdout);
                closesocket(sd2);
        }
}

client:

/* client.c - code for example client program that uses TCP */

#ifndef unix
#define WIN32
#include <windows.h>
#include <winsock.h>
#else
#define closesocket close
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#endif

#include <stdio.h>
#include <string.h>

#define PROTOPORT       5193            /* default protocol port number */

extern  int             errno;
char    localhost[] =   "localhost";    /* default host name            */
/*------------------------------------------------------------------------
 * Program:   client
 *
 * Purpose:   allocate a socket, connect to a server, and print all output
 *
 * Syntax:    client [ host [port] ]
 *
 *               host  - name of a computer on which server is executing
 *               port  - protocol port number server is using
 *
 * Note:      Both arguments are optional.  If no host name is specified,
 *            the client uses "localhost"; if no protocol port is
 *            specified, the client uses the default given by PROTOPORT.
 *
 *------------------------------------------------------------------------
 */
main(argc, argv)
int     argc;
char    *argv[];
{
        struct  hostent  *ptrh;  /* pointer to a host table entry       */
        struct  protoent *ptrp;  /* pointer to a protocol table entry   */
        struct  sockaddr_in sad; /* structure to hold an IP address     */
        int     sd;              /* socket descriptor                   */
        int     port;            /* protocol port number                */
        char    *host;           /* pointer to host name                */
        int     n;               /* number of characters read           */
        char    buf[1000];       /* buffer for data from the server     */
#ifdef WIN32
        WSADATA wsaData;
        WSAStartup(0x0101, &wsaData);
#endif
        memset((char *)&sad,0,sizeof(sad)); /* clear sockaddr structure */
        sad.sin_family = AF_INET;         /* set family to Internet     */

        /* Check command-line argument for protocol port and extract    */
        /* port number if one is specified.  Otherwise, use the default */
        /* port value given by constant PROTOPORT                       */

        if (argc > 2) {                 /* if protocol port specified   */
                port = atoi(argv[2]);   /* convert to binary            */
        } else {
                port = PROTOPORT;       /* use default port number      */
        }
        if (port > 0)                   /* test for legal value         */
                sad.sin_port = htons((u_short)port);
        else {                          /* print error message and exit */
                fprintf(stderr,"bad port number %s\n",argv[2]);
                exit(1);
        }

        /* Check host argument and assign host name. */

        if (argc > 1) {
                host = argv[1];         /* if host argument specified   */
        } else {
                host = localhost;
        }

        /* Convert host name to equivalent IP address and copy to sad. */

        ptrh = gethostbyname(host);
        if ( ((char *)ptrh) == NULL ) {
                fprintf(stderr,"invalid host: %s\n", host);
                exit(1);
        }
        memcpy(&sad.sin_addr, ptrh->h_addr, ptrh->h_length);

        /* Map TCP transport protocol name to protocol number. */

        if ( ((int)(ptrp = getprotobyname("tcp"))) == 0) {
                fprintf(stderr, "cannot map \"tcp\" to protocol number");
                exit(1);
        }

        /* Create a socket. */

        sd = socket(PF_INET, SOCK_STREAM, ptrp->p_proto);
        if (sd < 0) {
                fprintf(stderr, "socket creation failed\n");
                exit(1);
        }

        /* Connect the socket to the specified server. */

        if (connect(sd, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
                fprintf(stderr,"connect failed\n");
                exit(1);
        }

        /* Repeatedly read data from socket and write to user's screen. */

        n = recv(sd, buf, sizeof(buf), 0);
        while (n > 0) {
                write(1,buf,n);
                n = recv(sd, buf, sizeof(buf), 0);
        }

        /* Close the socket. */

        closesocket(sd);

        /* Terminate the client program gracefully. */

        exit(0);
}
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Discussion Span
Last Post by savoie
0

Hello jdm,

What does your programs actually:

The server
It is just waiting for incomming connection, and when a connection is done, it sends a string to the client after what he close the connection and wait for the next incomming connection.

The client
It connects the ther server, print incomming data to the standard output, and once the server cosed the connection, it close it socket too.

So I give you a little help server side
Once the client connect to the server, you need to buffer incomming data on the server until you get a null string charcater.

#include string.h

char incomming_buffer[100], incomming_count=0, tmp;
int n;

// Your code...

do{
  n = recv(sd2, &tmp, 1, 0);
  if(n>0) {
    *(incomming_buffer + incomming_count) = tmp;
    incomming_count++;
  }
}while((tmp != '\0') && (n < 1));

if(!strcmp(incomming_buffer, "Data10MB.dat")
{
  // Open your file

  // Send it through the socket
}
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