[C] Bug dans une application client-serveur très simple

#define _DEFAULT_SOURCE
#define SERVEUR_PORT 1664

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <arpa/inet.h>
#include <strings.h>
#include <unistd.h>

int main(void)
{
    printf("--- Programme client version 1.0.3 ---\n");

    struct sockaddr_in local_addr, serv_addr;
    int res, sockfd;

    // ------ Initialisation socket file descriptor --------
    sockfd = socket (PF_INET, SOCK_STREAM, 0);
    if (sockfd == -1)
    {
        fprintf(stderr, "Unable to initialize socket file descriptor.\n");
        return EXIT_FAILURE;
    }

    
    // ---- Initialisation de local_addr ------
    bzero (&local_addr, sizeof (struct sockaddr_in));

    local_addr.sin_port = htons(0);      // Le choix du port est laissé au système
    local_addr.sin_family = AF_INET;
    local_addr.sin_addr.s_addr = htonl(INADDR_ANY);


    // Lien
    res = bind (sockfd, (struct sockaddr *) &local_addr, sizeof (struct sockaddr_in));
    if (res == -1)
    {
        fprintf(stderr, "Unable to bind local socket.\n");
        close(sockfd);
        return EXIT_FAILURE;
    }


    // ---- Initialisation de serv_addr ------
    bzero (&serv_addr, sizeof (struct sockaddr_in));

    serv_addr.sin_port = htons(SERVEUR_PORT);
    serv_addr.sin_family = AF_INET;
    res = inet_aton("8.8.8.8", &(serv_addr.sin_addr));

    if (res == 0)
    {
        fprintf(stderr, "Unable to convert server address.\n");
        close(sockfd);
        return EXIT_FAILURE;
    }




    // Tout est prêt pour se connecter au serveur !
    printf("Pré-connexion réussie...\n");



    

    errno = 0;
    res = connect(sockfd, (struct sockaddr *) &serv_addr, sizeof (struct sockaddr_in));
   
    if (res == -1)
    {
        // Ce message s'affichera
        if (errno == ETIMEDOUT)
            printf("The attempt to connect timed out without establishing a connection.\n");
        
        
        fprintf(stderr, "Unable to connect to server.\n");
        close(sockfd);
        return EXIT_FAILURE;
    }


    
    printf("Connexion réussie !\n"); // Ne s'affichera pas hélas
    close (sockfd);

    return EXIT_SUCCESS;
}

#define _DEFAULT_SOURCE
#define SERVEUR_PORT 1664
#define BACKLOG 20

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <strings.h>
#include <unistd.h>



int main(void)
{
    printf("--- Programme serveur version 1.0.3 ---\n");

    struct sockaddr_in local_addr, cli_addr;
    int res, sockfd, cli_sockfd;
    socklen_t cli_size;

    // --- Initialisation socket file descriptor ---
    sockfd = socket (PF_INET, SOCK_STREAM, 0);
    if (sockfd == -1)
    {
        fprintf(stderr, "Unable to initialize socket file descriptor.\n");
        return EXIT_FAILURE;
    }


    // ---- Initialisation de local_addr ------
    bzero(&local_addr, sizeof (struct sockaddr_in));

    local_addr.sin_port = htons(SERVEUR_PORT);
    local_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    local_addr.sin_family = AF_INET;



    // ---- Lien ----
    res = bind(sockfd, (struct sockaddr *) &local_addr, sizeof (struct sockaddr_in));
    if (res == -1)
    {
        fprintf(stderr, "Unable to bind local socket.\n");
        close(sockfd);
        return EXIT_FAILURE;
    }




    // Mise en écoute du serveur
    res = listen(sockfd, BACKLOG);
    if (res == -1)
    {
        fprintf (stderr, "Listening failed.\n");
        close (sockfd);
        return EXIT_FAILURE;
    }




    // Cette étape réussit !
    printf("Mise en écoute...\n");





    // Accepte les connexion
    cli_sockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &cli_size);
    if (cli_sockfd == -1)
    {
        fprintf(stderr, "Unable to accept new client.\n");
        close(sockfd);
        return EXIT_FAILURE;
    }



    printf("Accepte les connexions... "); // échoue !
    close (cli_sockfd);
    close (sockfd);

    return EXIT_SUCCESS;
}