// This code is written by Souvik Ghosh
// Client side implementation of UDP client-server model
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8080
#define MAXLINE 1024

// Driver code
int main() {
    int sockfd;
    char buffer[MAXLINE];
    struct sockaddr_in servaddr;

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

    memset(&servaddr, 0, sizeof(servaddr));

    // Filling server information
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(PORT);
    servaddr.sin_addr.s_addr = INADDR_ANY;

    int n;

    socklen_t len;

    while (1) {
        printf("Enter message : ");
        fgets(buffer, MAXLINE, stdin);
        sendto(sockfd, (const char *)buffer, strlen(buffer),
               MSG_CONFIRM, (const struct sockaddr *)&servaddr,
               sizeof(servaddr));
        printf("Message sent.\n");

        n = recvfrom(sockfd, (char *)buffer, MAXLINE,
                     MSG_WAITALL, (struct sockaddr *)&servaddr,
                     &len);
        buffer[n] = '\0';
        printf("Server : %s\n", buffer);
        
        if ((strncmp(buffer,"bye",3)) == 0) {
            printf("Client Exit...\n");
            break;
        }
        }
        }

// This code is written by Souvik Ghosh
// Server side implementation of UDP client-server model
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8080
#define MAXLINE 1024

// Driver code
int main() {
    int sockfd;
    char buffer[MAXLINE];
    struct sockaddr_in servaddr, cliaddr;

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

    memset(&servaddr, 0, sizeof(servaddr));
    memset(&cliaddr, 0, sizeof(cliaddr));

    // Filling server information
    servaddr.sin_family = AF_INET; // IPv4
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);

    // Bind the socket with the server address
    if (bind(sockfd, (const struct sockaddr *)&servaddr,
             sizeof(servaddr)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    int len, n;

    len = sizeof(cliaddr); //len is value/resuslt

    while (1) {
        n = recvfrom(sockfd, (char *)buffer, MAXLINE,
                     MSG_WAITALL, (struct sockaddr *)&cliaddr,
                     &len);
        buffer[n] = '\0';
        printf("Client : %s\n", buffer);
        printf("Enter message : ");
        fgets(buffer, MAXLINE, stdin);
               sendto(sockfd, (const char *)buffer, strlen(buffer),
               MSG_CONFIRM, (const struct sockaddr *)&cliaddr,
               len);
        printf("message sent to client.\n");
    }

    return 0;
}