training_repo/UDP/server1.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080

int main() {
    int sockfd;
    char buffer[50];
    char sbuf[50];
    struct sockaddr_in server_addr, client_addr;
    socklen_t client_len;

    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY; // Bind to any address
    server_addr.sin_port = htons(PORT);

    if (bind(sockfd, (const struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("Bind failed");
        close(sockfd);
        exit(EXIT_FAILURE);
    }

    printf("Server listening on port %d\n", PORT);

    while (1) {

        client_len = sizeof(client_addr);
        int n = recvfrom(sockfd, buffer, sizeof(buffer), 0, (struct sockaddr *)&client_addr, &client_len);
        buffer[n] = '\0'; // Null-terminate the received string

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

        int length = n;
        
        sprintf(sbuf,"%d",n);
        sendto(sockfd, sbuf, sizeof(sbuf), 0, (const struct sockaddr *)&client_addr, client_len);
    }
    close(sockfd);
    return 0;
}