ns_sort.c

早期freebsd实现

#if !defined(lint) && !defined(SABER)
static char sccsid[] = "@(#)ns_sort.c	4.10 (Berkeley) 3/3/91";
static char rcsid[] = "$Id: ns_sort.c,v 4.9.1.2 1993/09/08 00:01:17 vixie Exp $";
#endif /* not lint */

/*
 * ++Copyright++ 1986, 1990
 * -
 * Copyright (c) 1986, 1990
 *    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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * 	This product includes software developed by the University of
 * 	California, Berkeley and its contributors.
 * 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.
 * -
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 * -
 * --Copyright--
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <syslog.h>
#include <resolv.h>

#include "named.h"

static int sort_rr();

struct netinfo *
local(from)
	struct sockaddr_in *from;
{
	struct netinfo *ntp;

	if (from->sin_addr.s_addr == netloop.my_addr.s_addr)
		return &netloop;
	for (ntp = nettab; ntp != *enettab; ntp = ntp->next) {
		if (ntp->net == (from->sin_addr.s_addr & ntp->mask))
			return ntp;
	}
	return NULL;
}

void
sort_response(cp, ancount, lp, eom)
	register char *cp;
	register int ancount;
	struct netinfo *lp;
	u_char *eom;
{
	register struct netinfo *ntp;

	dprintf(3, (ddt, "sort_response(%d)\n", ancount));
	if (ancount > 1) {
		if (sort_rr(cp, ancount, lp, eom))
			return;
		for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
			if ((ntp->net == lp->net) && (ntp->mask == lp->mask))
				continue;
			if (sort_rr(cp, ancount, ntp, eom))
				break;
		}
	}
}

static int
sort_rr(cp, count, ntp, eom)
	register u_char *cp;
	int count;
	register struct netinfo *ntp;
	u_char *eom;
{
	int type, class, dlen, n, c;
	struct in_addr inaddr;
	u_char *rr1;

#ifdef DEBUG
	if (debug > 2) {
	    inaddr.s_addr = ntp->net;
	    fprintf(ddt,"sort_rr( x%x, %d, [%s])\n",
		    cp, count, inet_ntoa(inaddr));
	}
#endif
	rr1 = NULL;
	for (c = count; c > 0; --c) {
	    n = dn_skipname(cp, eom);
	    if (n < 0)
		return (1);		/* bogus, stop processing */
	    cp += n;
	    if (cp + QFIXEDSZ > eom)
		return (1);
	    GETSHORT(type, cp);
	    GETSHORT(class, cp);
	    cp += sizeof(u_int32_t);
	    GETSHORT(dlen, cp);
	    if (dlen > eom - cp)
		return (1);		/* bogus, stop processing */
	    switch (type) {
	    case T_A:
	    	switch (class) {
	    	case C_IN:
	    	case C_HS:
	    		bcopy(cp, (char *)&inaddr, sizeof(inaddr));
			if (rr1 == NULL)
				rr1 = cp;
			if ((ntp->mask & inaddr.s_addr) == ntp->net) {
			    dprintf(2, (ddt,"net [%s] best choice\n",
					inet_ntoa(inaddr)));
			    if (rr1 != cp) {
	    		        bcopy(rr1, cp, sizeof(inaddr));
	    		        bcopy((char *)&inaddr, rr1, sizeof(inaddr));
			    }
			    return(1);
			}
	    		break;
	    	}
	    	break;
	    }
	    cp += dlen;
	}
	return(0);
}