UDP Client server communication Program in c

Connectionless  Program

UDP Client Server Communication      ( Connectionless  Data Transfer )

Sender side Function:
                            socket();
                             bind();
                             recvfrom(); / sendto();
                            close();

Client side Functions:
                             socket();
                             sendto() / recvfrom();

                             close();


                    // UDP SERVER PROGRAM

#include <stdio.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include<netinet/in.h>
#include<sys/types.h>




int main()
{

char buff[2000];
int sd,connfd,len;

struct sockaddr_in servaddr,cliaddr;

sd = socket(AF_INET, SOCK_DGRAM, 0);

if(sd==-1)
{
    printf(" socket not created in server\n");
    exit(0);
}
else
{
    printf("socket created in  server\n");
}

bzero(&servaddr, sizeof(servaddr));

servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(7802);

if ( bind(sd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0 )
    printf("Not binded\n");
else
    printf("Binded\n");

len=sizeof(cliaddr);

recvfrom(sd,buff,1024,0,
                   (struct sockaddr *)&cliaddr, &len);

    printf("UDP Server received msg from UDP client  %s",buff);

close(sd);
  
return(0);
}




                        // UDP CLIENT PROGRAM

#include <stdio.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include<netinet/in.h>
#include<sys/types.h>


int main()
{
char buff[2000];
int sockfd,connfd,len;

struct sockaddr_in servaddr,cliaddr;

// create socket in client side
sockfd = socket(AF_INET, SOCK_DGRAM, 0);

if(sockfd==-1)
{
    printf(" socket not created in client\n");
    exit(0);
}
else
{
    printf("socket created in  client\n");
}


bzero(&servaddr, sizeof(servaddr));

servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY; // ANY address or use specific address
servaddr.sin_port = htons(7802);  // Port address


    printf("Type ur  UDP client message\n");
    scanf("%s",buff);

// send  msg to server

sendto(sockfd, buff, strlen(buff), 0,
              (struct sockaddr *)&servaddr, sizeof(struct sockaddr));

//close client side connection
close(sockfd);

return(0);
}


Steps:
       1) Compile and Run Server Program   cc udpserver.c   ./a.out
        2) Compile and Run Client Program   cc udpclient.c     ./a.out
        3) Enter Message in Client