client_test1.c

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

int main() {
    int udp_socket = socket(AF_INET, SOCK_DGRAM, 0);
    if (udp_socket < 0) {
        printf("Error creating socket\n");
        return 1;
    }

    struct sockaddr_in server_addr;
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(8060);
    inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr);

    char message[] = "Hello World!";
    
    struct msghdr msg;
    memset(&msg, 0, sizeof(msg));
    msg.msg_name = &server_addr;
    msg.msg_namelen = sizeof(server_addr);

    struct iovec iov;
    iov.iov_base = message;
    iov.iov_len = sizeof(message);
    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;

    int bytes_sent = sendmsg(udp_socket, &msg, 0);
    if (bytes_sent < 0) {
        printf("Error sending message\n");
        return 1;
    }
    
    char buffer[1024];

    memset(buffer, 0, sizeof(buffer));

    struct sockaddr_in client_addr;
    socklen_t client_addr_len = sizeof(client_addr);
    struct msghdr recv_msg;
    memset(&recv_msg, 0, sizeof(recv_msg));
    recv_msg.msg_name = &client_addr;
    recv_msg.msg_namelen = sizeof(client_addr);

    struct iovec recv_iov;
    recv_iov.iov_base = buffer;
    recv_iov.iov_len = sizeof(buffer);
    recv_msg.msg_iov = &recv_iov;
    recv_msg.msg_iovlen = 1;

    int bytes_received = recvmsg(udp_socket, &recv_msg, 0);
    if (bytes_received < 0) {
        printf("Error receiving message\n");
        return 1;
    }

    printf("Received message: %s\n", buffer);
    
    close(udp_socket);

    return 0;
}