client_udp.c

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

#define PORT 8888
#define BUFFER_SIZE 1024

int main(int argc, char *argv[]) {
    int sockfd;
    struct sockaddr_in server_addr;
    char message[BUFFER_SIZE];
    int bytes_sent;
    
    /* Vérifier les arguments */
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <server_ip>\n", argv[0]);
        fprintf(stderr, "Exemple: %s 127.0.0.1\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    
    /* Créer le socket UDP */
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("Erreur de création du socket");
        exit(EXIT_FAILURE);
    }
    
    /* Configurer l'adresse du serveur */
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr(argv[1]);
    
    printf("Client UDP - Envoi sans accusé de réception\n");
    printf("Tapez vos messages (ou 'quit' pour quitter)\n\n");
    
    while (1) {
        /* Saisir le message */
        printf("Message: ");
        fgets(message, BUFFER_SIZE, stdin);
        message[strcspn(message, "\n")] = 0;  /* Supprimer le saut de ligne */
        
        /* Vérifier si l'utilisateur veut quitter */
        if (strcmp(message, "quit") == 0) {
            printf("Au revoir!\n");
            break;
        }
        
        /* Envoyer le message (sans attendre de réponse) */
        bytes_sent = sendto(sockfd, message, strlen(message), 0,
                           (struct sockaddr *)&server_addr, sizeof(server_addr));
        
        if (bytes_sent < 0) {
            perror("Erreur d'envoi");
        } else {
            printf("Message envoyé (%d octets)\n", bytes_sent);
        }
        
        /* Pas de recvfrom() - pas d'accusé de réception */
    }
    
    close(sockfd);
    return 0;
}

serveur_udp.c

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

#define PORT 8888
#define BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in server_addr, client_addr;
    char buffer[BUFFER_SIZE];
    socklen_t addr_len = sizeof(client_addr);
    int bytes_received;
    
    /* Créer le socket UDP */
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("Erreur de création du socket");
        exit(EXIT_FAILURE);
    }
    
    /* Configurer l'adresse du serveur */
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = INADDR_ANY;
    
    /* Attacher le socket au port */
    if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("Erreur de bind");
        close(sockfd);
        exit(EXIT_FAILURE);
    }
    
    printf("Serveur UDP en écoute sur le port %d...\n", PORT);
    printf("En attente de messages (Ctrl+C pour quitter)\n\n");
    
    while (1) {
        /* Recevoir un message (sans envoyer de confirmation) */
        bytes_received = recvfrom(sockfd, buffer, BUFFER_SIZE - 1, 0,
                                 (struct sockaddr *)&client_addr, &addr_len);
        
        if (bytes_received < 0) {
            perror("Erreur de réception");
            continue;
        }
        
        buffer[bytes_received] = '\0';
        printf("[%s:%d] %s\n",
               inet_ntoa(client_addr.sin_addr),
               ntohs(client_addr.sin_port),
               buffer);
    }
    
    close(sockfd);
    return 0;
}