proj4_4.cpp

利用udp协议实现端口扫描

#include <stdlib.h>
#include <stdio.h>
#include <winsock.h>
#include <winbase.h>

#define	BUFSIZE		  64
#define	WSVERS		MAKEWORD(2, 0)

#define	WINEPOCH	2208988800	
#define	MSG		"Is this port you open?\n"
#define MAX_PACKET 1024
SOCKET connectsock(const char *host, const char *service,
				   const char *transport );
void	errexit(const char *, ...);
int main(int argc, char *argv[])
{
	char	*host = "localhost";	/* host to use if none supplied	*/
	char	*service = "5060";	/* default service name		*/
	SOCKET	s;		  	/* socket descriptor		*/
	int errcnt = 0;			/* error count */
	WSADATA	wsadata;
	switch (argc) {
	case 1:
		break;
	case 3:
		service = argv[2];
		/* FALL THROUGH */
	case 2:
		host = argv[1];
		break;
	default:
		fprintf(stderr, "usage: file1.exe [host [port]]\n");
		exit(1);
	}
	if (WSAStartup(WSVERS, &wsadata))
		errexit("WSAStartup failed\n");
	s = connectsock(host, service, "udp");
    (void) send(s, MSG, strlen(MSG), 0);
	closesocket(s);
	WSACleanup();
	return 1;
}

#ifndef	INADDR_NONE
#define	INADDR_NONE	0xffffffff
#endif	/* INADDR_NONE */
/*------------------------------------------------------------------------
* connectsock - allocate & connect a socket using TCP or UDP
*------------------------------------------------------------------------
*/
SOCKET connectsock(const char *host, const char *service, const char *transport )
{
	struct hostent	*phe;	/* pointer to host information entry	*/
	struct servent	*pse;	/* pointer to service information entry	*/
	struct protoent *ppe;	/* pointer to protocol information entry*/
	struct sockaddr_in sin;	/* an Internet endpoint address		*/
	int	s, type;	/* socket descriptor and socket type	*/
	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
    /* Map service name to port number */
	if ( pse = getservbyname(service, transport) )
		sin.sin_port = pse->s_port;
	else if ( (sin.sin_port = htons((u_short)atoi(service))) == 0 )
		errexit("can't get \"%s\" service entry\n", service);
    /* Map host name to IP address, allowing for dotted decimal */
	if ( phe = gethostbyname(host) )
		memcpy(&sin.sin_addr, phe->h_addr, phe->h_length);
	else if ( (sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE)
		errexit("can't get \"%s\" host entry\n", host);
    /* Map protocol name to protocol number */
	if ( (ppe = getprotobyname(transport)) == 0)
		errexit("can't get \"%s\" protocol entry\n", transport);
    /* Use protocol to choose a socket type */
	if (strcmp(transport, "udp") == 0)
		type = SOCK_DGRAM;
	else
		type = SOCK_STREAM;
    /* Allocate a socket */
	s = socket(PF_INET, type, ppe->p_proto);
	if (s == INVALID_SOCKET)
		errexit("can't create socket: %d\n", GetLastError());
    /* Connect the socket */
	if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) ==
		SOCKET_ERROR)
		errexit("can't connect to %s.%s: %d\n", host, service,
		GetLastError());
	return s;
}
void errexit(const char *format, ...)
{
	va_list	args;
	va_start(args, format);
	vfprintf(stderr, format, args);
	va_end(args);
	WSACleanup();
	exit(1);
}