x_ping.c

来自「TCP-IP红宝书源代码」· C语言 代码 · 共 61 行

/* x_ping.c - x_ping */

#include <conf.h>
#include <kernel.h>
#include <network.h>

/*------------------------------------------------------------------------
 *  x_ping  -  do ICMP echo to a given destination
 *------------------------------------------------------------------------
 */
COMMAND
x_ping(stdin, stdout, stderr, nargs, args)
int	stdin, stdout, stderr, nargs;
char	*args[];
{
	char	str[80], host[32], *p;
	IPaddr	dst;
	int	got, i;
	int	np, ds;		/* # packets to send, data size */

	ds = 56;
	if (nargs == 3) {
		ds = atoi(args[2]);
	} else if (nargs != 2) {
		sprintf(str, "usage: ping host [size]\n");
		write(stderr, str, strlen(str));
		return OK;
	}
	dst = name2ip(args[1]);

	got = 0;
	np = 10;
	i = 0;
	while(TRUE) {
		struct ep *packet;

		packet = (struct ep *)recvtim(10);	/* wait up to 1 sec */
		if (packet != (struct ep *)TIMEOUT) {
			struct ip *pip = (struct ip *)packet->ep_data;
			struct icmp *pic = (struct icmp *)pip->ip_data;

			sprintf(str, "%d octets from %s: icmp_seq %d\n",
				pip->ip_len - IP_HLEN(pip),
				ip2dot(host, pip->ip_src),
				pic->ic_seq);
			write(stdout, str, strlen(str));
			freebuf(packet);
			got++;
		} else {
			if (i >= np)
				break;
			icmp(ICT_ECHORQ, 0, dst, i, ds);
			i++;
		}
	}
	sprintf(str, "received %d/%d packets (%d %% loss)\n", got, 10,
		(100 * (10-got))/10);
	write(stdout, str, strlen(str));
	return(OK);
}