client.c

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <wait.h>

void main () {
	int i, verbose = 0, port_number, rexmt;
	char option, hostname[16];
	/* Socket data */
	int in_socket_id, socket_id, server_socket_sz;
	struct sockaddr_in client_socket, server_socket, in_socket;
	struct hostent *hostp;

	/* Transmission data */
	char msg_buffer[1024], data_buffer[512], error[300], ack[4];
	int offset = 0, bytes_rcvd, ack_recvd;
	unsigned short block_number, opcode;

	if ((socket_id = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
			return;
	}
	in_socket.sin_family = AF_INET;
	in_socket.sin_port = htons(0);
	in_socket.sin_addr.s_addr = INADDR_ANY;

	if (bind(socket_id, (struct sockaddr *) &in_socket, sizeof(in_socket)) == -1) {
		return;
	}

	if ((hostp = gethostbyname(hostname)) == 0) {
		return;
	}
	bzero((char *) &client_socket, sizeof(client_socket));
	client_socket.sin_family = AF_INET;
	client_socket.sin_port = htons(8724);
	bcopy(hostp->h_addr, (char *) &client_socket.sin_addr, hostp->h_length);

	bzero(msg_buffer,sizeof(msg_buffer));
	memcpy(msg_buffer,"mensaje\0",sizeof("mensaje\0"));

	socklen_t client_socket_len = sizeof(struct sockaddr_in);
	if (sendto(socket_id, msg_buffer, sizeof(msg_buffer), 0, (struct sockaddr *) &client_socket, client_socket_len) < 0) {
		return;
	}
	bzero(msg_buffer,sizeof(msg_buffer));
	if(recvfrom(socket_id, msg_buffer, sizeof(msg_buffer), 0, (struct sockaddr *) &client_socket, &client_socket_len) == -1) {
		return;
	}
	printf("%s\n", msg_buffer);
}