udp_svr.c

一个基于linux的TCP/IP协议栈的实现

#include <sys/socket.h>
#include <linux/types.h>
#include <linux/errqueue.h>
#include <sys/ioctl.h>
#include "my_inet.h"
#include <stdio.h>
#include <errno.h>
#include <string.h>

#include <arpa/inet.h>
#include <unistd.h>

int main()
{
	int i;
	struct sockaddr_in sa;
	struct sockaddr_in r_sa;

	sa.sin_family = PF_INET;
	sa.sin_port = htons(16000);
	inet_aton("172.16.48.2", &sa.sin_addr);

	int fd = socket( MY_PF_INET, SOCK_DGRAM, MY_IPPROTO_UDP );
	if( fd < 0 ){
		perror("socket: ");
		return -1;
	}
	
	if( bind( fd, (struct sockaddr *)&sa, sizeof(sa) ) == -1 )
		perror("bind: ");
	
	//int bwrite = send( fd, "abcdefg", 7, 0 );
	//if( bwrite == -1 ){
	//	perror("send: ");
	//	return -1;
	//}
	
	printf("wait for msg!\n");
	char buf[1024];
	int len = sizeof(r_sa);
	int bread = recvfrom( fd, buf, 1024, 0, (struct sockaddr *)&r_sa, (socklen_t*)&len );
	if( bread == -1 ){
		perror("recv: ");
		return -1;
	}
	printf("%s\n", buf);
	printf("%s, %u\n", inet_ntoa( r_sa.sin_addr ), ntohs(r_sa.sin_port) );
	if( sendto( fd, buf, strlen(buf), 0, (struct sockaddr *)&r_sa, len ) == -1 )
		perror("sendto: ");

	do{
		sleep(1);
	}while(1);
	close( fd );
	return 0;
}