Socket programming with UDP | UDP Socket program in UNIX | Server - Client socket program using UDP

     Socket programming with UDP

UDP Socket Program - Server

// Server side implementation of UDP client-server model

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <netinet/in.h>

 

#define PORT     8080

#define MAXLINE 1024

 

// Driver code

int main() {

     int sockfd;

     char buffer[MAXLINE];

     char *hello = "Hello from server";

     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

 

     n = recvfrom(sockfd, (char *)buffer, MAXLINE,

                                         MSG_WAITALL, ( struct sockaddr *) &cliaddr,

                                         &len);

     buffer[n] = '\0';

     printf("Client : %s\n", buffer);

     sendto(sockfd, (const char *)hello, strlen(hello),

                 MSG_CONFIRM, (const struct sockaddr *) &cliaddr,

                             len);

     printf("Hello message sent.\n");

    

     return 0;

}

 

Output:

$ ./server

Client : Hello from client

Hello message sent.

 

UDP Socket Program - Client

// Client side implementation of UDP client-server model

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <netinet/in.h>

 

#define PORT     8080

#define MAXLINE 1024

 

// Driver code

int main() {

     int sockfd;

     char buffer[MAXLINE];

     char *hello = "Hello from client";

     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, len;

    

     sendto(sockfd, (const char *)hello, strlen(hello),

                 MSG_CONFIRM, (const struct sockaddr *) &servaddr,

                             sizeof(servaddr));

     printf("Hello message sent.\n");

                

     n = recvfrom(sockfd, (char *)buffer, MAXLINE,

                                         MSG_WAITALL, (struct sockaddr *) &servaddr,

                                         &len);

     buffer[n] = '\0';

     printf("Server : %s\n", buffer);

 

     close(sockfd);

     return 0;

}

 

Output:

$ ./client

Hello message sent.

Server : Hello from server