get_addrs.c

linux下常用的网络工具的代码

/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)get_addrs.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#ifdef HAVE_OSOCKADDR_H
#include <osockaddr.h>
#endif
#include <protocols/talkd.h>
#include <netdb.h>
#include <stdio.h>
#include "talk_ctl.h"

int
get_addrs(char *my_machine_name, char *his_machine_name)
{
	struct hostent *hp;
	struct servent *sp;

	msg.pid = htonl(getpid());
	/* look up the address of the local host */
	hp = gethostbyname(my_machine_name);
	if (hp == NULL) {
		fprintf(stderr, "talk: %s: ", my_machine_name);
		herror((char *)NULL);
		exit(-1);
	}
	bcopy(hp->h_addr, (char *)&my_machine_addr, hp->h_length);
	/*
	 * If the callee is on-machine, just copy the
	 * network address, otherwise do a lookup...
	 */
	if (strcmp(his_machine_name, my_machine_name)) {
		hp = gethostbyname(his_machine_name);
		if (hp == NULL) {
			fprintf(stderr, "talk: %s: ", his_machine_name);
			herror((char *)NULL);
			exit(-1);
		}
		bcopy(hp->h_addr, (char *) &his_machine_addr, hp->h_length);
	} else
		his_machine_addr = my_machine_addr;
	/* find the server's port */
	sp = getservbyname("ntalk", "udp");
	if (sp == 0) {
		fprintf(stderr, "talk: %s/%s: service is not registered.\n",
		     "ntalk", "udp");
		exit(-1);
	}
	daemon_port = sp->s_port;
}