ping.c

判断网络上某个TCP/IP主机是否可以连通的C函数库

#include "./include.h"

char usage[]="Usage:Ping [-drv] host [datasize] [npackets]\n";
char hnamebuf[MAXHOSTNAMELEN];
char *pname;

main(argc, argv)
int argc;
char **argv;
{
	int sockoption, on;
	char *destdotaddr ;
	struct protoent *proto; 	/*--- include in netdb.h ---*/
	struct hostent  *host;
	extern void sig_finish();
	extern void sig_alarm();

	on=1;
	ntransmitted = 0;
	npackets = 0 ;
	timing = 0;
	verbose = 0 ;

	pname = argv[0];	// pin
	argc --;
	argv++;
	sockoption = 0;
	while( argc > 0 && *argv[0] == '-' ) {
		while(*++argv[0]) switch( *argv[0]) {
			case 'd':
				sockoption |= SO_DEBUG;
				break;
			case 'r':
				sockoption |= SO_DONTROUTE;
				break;
			case 'v':
				verbose ++;
				break;
		}
		argc --; argv ++;
	}
	if ( argc < 1 ) err_sys( usage ) ;

	/*---------------------------------------
	**  struct sockaddr_in {
	**	short sin_family;
	**	u_short sin_port;
	**	struct in_addr sin_addr ;
	**	char sin_zero[8];
	**	}
	**  struct in_addr {
	**	u_long          s_addr;
	**	};
	**-------------------------------------*/
	bzero( (char *) &dest, sizeof( dest ) );
	dest.sin_family = AF_INET;
	if( (dest.sin_addr.s_addr=inet_addr(argv[0]) ) != INADDR_NONE ) {
		/*------ 格式: 130.150.160.1 -------*/
		strcpy( hnamebuf, argv[0] );
		hostname = hnamebuf ; 
		destdotaddr = NULL;
	} 
	else {
		/*------ 格式: lsd01 ---------------*/

	/*----------  struct hostent (netdb.h)-----------------
	**struct hostent {
	**	char    *h_name;	official name of host
	**	char    **h_aliases;	alias list
	**	int     h_addrtype;	host address type
	**	int     h_length;	length of address
	**	char    **h_addr_list;	list of addresses from name server
	**      #define	h_addr	h_addr_list[0]
	**--------------------------------------------*/

		if ( ( host=gethostbyname( argv[0] )) == NULL ) {
			err_quit( "主机名(%s)出错 \n", argv[0] );
		}
		dest.sin_family = host->h_addrtype;
		bcopy( host->h_addr, (caddr_t)&dest.sin_addr,host->h_length);
		hostname = host->h_name;

		/*--- inet_ntoa 将LONG地址转换成130.150.160.10 ----*/
		destdotaddr = (char *)inet_ntoa( dest.sin_addr.s_addr );
	}

	if ( argc >= 2 ) datalen = atoi( argv[1] );
	else		 datalen = DEF_DATALEN;

	packsize = datalen + SIZE_ICMP_HDR ;
	if ( packsize > MAXPACKET ) 
		err_quit( "ICMP包大小不能大于%d\n" ,MAXPACKET-SIZE_ICMP_HDR);
	if ( datalen >= SIZE_TIME_DATA ) timing = 1;

	if ( argc > 2 ) npackets = atoi ( argv[2] );

	ident = getpid() & 0xffff;		/* why & 0xffff ? */
	/*--------------------(include in dbnet.h)----------------
	**struct protoent {
	**	char           *p_name;		official protocol name 
	**	char          **p_aliases;	alias list 
	**	int             p_proto;	protocol # 
	**-----------------------------------------------------*/
	if ( (proto=getprotobyname( "icmp" ) ) == NULL )
		err_sys( "ICMP PROTO IS NOT CREATE! " );
	if ( ( sockfd == socket( AF_INET, SOCK_RAW, proto->p_proto ) ) < 0 )
		err_sys( "不能创建SOCKET!" );

	if ( sockoption & SO_DEBUG ) 
		if ( setsockopt( sockfd, SOL_SOCKET, SO_DEBUG, &on, 
			sizeof(on) ) < 0 ) 
			err_sys( "设置SO_DEBUG出错\n" ) ;
	if( sockoption & SO_DONTROUTE ) 
		if ( setsockopt( sockfd, SOL_SOCKET, SO_DONTROUTE, &on, 
			sizeof(on) ) < 0 ) 
			err_sys( "设置SO_DONTROUTE出错\n" ) ;
	/*-------- 输出提示信息 -----------*/
	printf( "PING %s", hostname );		
	if ( destdotaddr) 	//格式lsd01
		printf( "(%s)", destdotaddr); 
	printf( ":%d 字节\n" , datalen );		

	tmin = 99999999;

	/*
	setlinebuf( stdout ) ;
	*/

	signal ( SIGINT, sig_finish );
	signal ( SIGALRM,sig_alarm );
	sig_alarm ();
	recv_ping();
}
/*
**	时间信号处理
**
*/
void sig_alarm()
{
	int waittime;
	extern void sig_finish();
	send_ping();
	if ( npackets == 0 || ntransmitted < npackets ) 
		alarm(1);
	else {
		npackets = 1;
		if ( nreceived ) {
			waittime = 2 * tmax /1000;
			if ( waittime == 0 ) waittime = 1;
		}else {
			waittime = MAXWAIT ;
			signal ( SIGALRM, sig_finish );
			alarm ( waittime );
		}
		return ;
	}
}
/*
**	每隔一个时间片发送ICMP包
**
*/
send_ping()
{
	register int i;
	register struct icmp *icp;
	register u_char *uptr;

	/*--- ICMP 包头 ----*/
	/* struct icmp {
	**	u_char 	icmp_type ;	
	**	u_char  icmp_code ;
	**	u_short icmp_chksum;     包检查大小
	**	u_short icmp_id ;
	**	u_short icmp_seq;
	**	char 	icmp_data[1];	 经常放时间 
	*/

	icp = (struct icmp *) sendpack;   /* u_char sendpack[MAXPACKET]; */
	icp->icmp_type = ICMP_ECHO;
	icp->icmp_code = 0;
	icp->icmp_cksum = 0;
	icp->icmp_id = ident;
	icp->icmp_seq = ntransmitted ++;
	
	if ( timing ) 
		/**----- datalen >= SIZE_TIME_DATA ) ----------**/
		/**--------放时间于icmp_data[SIZE_TIME_DATA]---**/
		gettimeofday( (struct timeval *) &sendpack[SIZE_ICMP_HDR],
				(struct tiemzone *) 0 );

	/**--- 填充ICMP包从SIZE_ICMP_HDR+SIZE_TIME_DATA(def=16)起(def=56)个 --*/
	uptr = &sendpack[SIZE_ICMP_HDR+SIZE_TIME_DATA];
	for ( i = SIZE_TIME_DATA; i< datalen; i++ )
		*uptr++ = i;

	icp->icmp_cksum=in_chksum( icp, packsize );
	i = sendto( sockfd, sendpack , packsize , 0, (struct sockaddr *)&dest,
		sizeof( dest ) );
	if ( i < 0 || i != packsize ) {
		if ( i < 0 ) {
			err_sys( "sendto error " ) ;
		}
		else err_quit( "wrote %s %d bytes , return = %d\n", 
				hostname , packsize , i ) ;
	}

}

/*
**	得出ICMP包大小的校验值
**
**/
int in_chksum( ptr, nbytes ) 
u_short *ptr ;
int nbytes ;
{
	register long sum;
	u_short       oddbyte;
	register u_short answer;

	sum = 0 ;
	/***------ 两位一次检查 ------**/
	while( nbytes>1 ) {
		sum+=*ptr++;
		nbytes-=2;
	}

	if ( nbytes == 1 ) {
		/**----- 剩下最后一位,加上 -------**/
		oddbyte= 0;
		*((u_char *)&oddbyte )  =*(u_char *)ptr ;
		sum+=oddbyte;
	}	
	sum=(sum>>16) + (sum&0xffff);
	sum += ( sum>>16 );
	answer = -sum;		/** turn to 16 bits **/
	return ( answer ) ;
}
/*
**	接收返回信息
*/
recv_ping()
{
	register int n;
	int 	fromlen;
	struct sockaddr_in from ;
	extern void sig_finish();
	for ( ;; ) {
		fromlen = sizeof( from );
		if ( ( n = recvfrom ( sockfd, recvpack, sizeof( recvpack ) , 
			0 , (struct sockaddr *)&from, &fromlen ) ) < 0 ) {
			if ( errno == EINTR )  /** 因为ALARM调用会引起
						   NORMAL中断       */
				continue;
			printf( "errno=%d,errstr=%s, 接收数据出错!",
				errno, sys_errlist[errno] ) ; 
			continue;
		}
		pr_pack( recvpack, n, &from ) ;
		if ( npackets &&  nreceived >=npackets ) 
			sig_finish();
	}

}
pr_pack( buf, cc, from ) 
char *buf;
int cc; 
struct sockaddr_in *from ;
{
	int i, iphdrlen, triptime;
	struct ip *ip;
	register struct icmp *icp;
	long *lp;
	struct timeval tv;
	char *pr_type();
	from->sin_addr.s_addr = ntohl( from->sin_addr.s_addr ) ;
	if ( timing ) 
		gettimeofday( &tv, ( struct timezone *)0 ) ;
	ip = (struct ip *)buf ;
	iphdrlen = ip->ip_hl<<2;
	if ( cc < iphdrlen + ICMP_MINLEN ) {
		if ( verbose ) 
			printf( "包太小 (%d bytes ) from %s\n", cc, 
				inet_ntoa( ntohl( from->sin_addr.s_addr ) ));
			return ;
	} 
	cc-=iphdrlen ;
	icp = ( struct icmp *) ( buf + iphdrlen ) ;
	if ( icp->icmp_type != ICMP_ECHOREPLY ) {




	}

}
char *pr_type()
{
}

void sig_finish()
{
	alarm(0);
	exit(0);
}

err_sys(s)
char *s;
{
	if ( errno > 0 && errno <sys_nerr ) 
		printf( "errno=%d:%s. %s\n", errno, sys_errlist[errno], s );
	else printf( "errno=%d:%s\n", errno, s );
	exit(0);
}
/*
**
*/
err_quit( s, parm )
char *s;
char **parm ;
{
	printf( s, parm ); 
	exit(0);
}