Sunday, February 26, 2012

Simple UDP Client


/* UDP client in the internet domain */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define MIN(x, y)  ((x) < (y) ? (x) : (y))
#define MAX(x, y)  ((x) > (y) ? (x) : (y))

void error(const char *);

int main(int argc, char *argv[])
   int sock, n;
   unsigned int length;
   struct sockaddr_in server, from;
   struct hostent *hp;
   char buffer[256];

   if (argc < 3) {
        printf("Usage: %s <port>\n", argv[0]);
   sock= socket(AF_INET, SOCK_DGRAM, 0);
   if (sock < 0) error("socket");

   server.sin_family = AF_INET;
   hp = gethostbyname(argv[1]);
   if (hp==0) error("Unknown host");

   bcopy((char *)hp->h_addr,
        (char *)&server.sin_addr,
   server.sin_port = htons(atoi(argv[2]));
   length=sizeof(struct sockaddr_in);
   printf("Please enter the message: ");
   bzero(buffer, sizeof(buffer));
   fgets(buffer, sizeof(buffer)-1, stdin);
            strlen(buffer),0,(const struct sockaddr *)&server,length);
   if (n < 0)
   n = recvfrom(sock, buffer, sizeof(buffer), 0, (struct sockaddr *)&from, &length);
   if (n < 0)
   printf("Got an ack: %d bytes\n", n);
   write(1, buffer, MIN(n, strlen(buffer)));
   return 0;

void error(const char *msg)


No comments:

Post a Comment