info_hes.c

早期freebsd实现

/*
 * Copyright (c) 1989 Jan-Simon Pendry
 * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * 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.
 *
 *	@(#)info_hes.c	8.1 (Berkeley) 6/6/93
 *
 * $Id: info_hes.c,v 5.2.2.1 1992/02/09 15:08:29 jsp beta $
 *
 */

/*
 * Get info from Hesiod
 *
 * Zone transfer code from Bruce Cole <[e-mail]>
 */

#include "am.h"

#ifdef HAS_HESIOD_MAPS
#include <hesiod.h>

#define	HES_PREFIX	"hesiod."
#define	HES_PREFLEN	7

#ifdef HAS_HESIOD_RELOAD
#include <arpa/nameser.h>
#include <resolv.h>
#include <sys/uio.h>
#include <netdb.h>

/*
 * Patch up broken system include files
 */
#ifndef C_HS
#define C_HS	4
#endif
#ifndef T_TXT
#define	T_TXT	16
#endif

static int soacnt;
static struct timeval hs_timeout;
static int servernum;
#endif /* HAS_HESIOD_RELOAD */

/*
 * No easy way to probe the server - check the map name begins with "hesiod."
 */
int hesiod_init P((char *map, time_t *tp));
int hesiod_init(map, tp)
char *map;
time_t *tp;
{
#ifdef DEBUG
	dlog("hesiod_init(%s)", map);
#endif
	*tp = 0;
	return strncmp(map, HES_PREFIX, HES_PREFLEN) == 0 ? 0 : ENOENT;
}


/*
 * Make Hesiod name.  Skip past the "hesiod."
 * at the start of the map name and append
 * ".automount".  The net effect is that a lookup
 * of /defaults in hesiod.home will result in a
 * call to hes_resolve("/defaults", "home.automount");
 */
#ifdef notdef
#define MAKE_HES_NAME(dest, src) sprintf(dest, "%s%s", src + HES_PREFLEN, ".automount")
#endif

/*
 * Do a Hesiod nameserver call.
 * Modify time is ignored by Hesiod - XXX
 */
int hesiod_search P((mnt_map *m, char *map, char **pval, time_t *tp));
int hesiod_search(m, map, key, pval, tp)
mnt_map *m;
char *map;
char *key;
char **pval;
time_t *tp;
{
	int error;
	char hes_key[MAXPATHLEN];
	char **rvec;
#ifdef DEBUG
	dlog("hesiod_search(m=%x, map=%s, key=%s, pval=%x tp=%x)", m, map, key, pval, tp);
#endif
	/*MAKE_HES_NAME(hes_map, map);*/
	sprintf(hes_key, "%s.%s", key, map+HES_PREFLEN);

	/*
	 * Call the resolver
	 */
#ifdef DEBUG
	dlog("hesiod_search: hes_resolve(%s, %s)", hes_key, "automount");
#ifdef HAS_HESIOD_RELOAD
	if (debug_flags & D_FULL)
		_res.options |= RES_DEBUG;
#endif
#endif
	rvec = hes_resolve(hes_key, "automount");
	/*
	 * If a reply was forthcoming then return
	 * it (and free subsequent replies)
	 */
	if (rvec && *rvec) {
		*pval = *rvec;
		while (*++rvec)
			free(*rvec);
		return 0;
	}

	/*
	 * Otherwise reflect the hesiod error into a Un*x error
	 */
#ifdef DEBUG
	dlog("hesiod_search: Error: %d", hes_error());
#endif
	switch (hes_error()) {
	case HES_ER_NOTFOUND:	error = ENOENT; break;
	case HES_ER_CONFIG:	error = EIO; break;
	case HES_ER_NET:	error = ETIMEDOUT; break;
	default:		error = EINVAL; break;
	}
#ifdef DEBUG
	dlog("hesiod_search: Returning: %d", error);
#endif
	return error;
}

#ifdef HAS_HESIOD_RELOAD
/*
 * Zone transfer...
 */

#define MAXHSNS 8
#define MAX_NSADDR 16

static char *hs_domain;
static mnt_map *hs_map;
static int hs_nscount;
static char nsaddr_list[MAX_NSADDR][sizeof(struct in_addr)];

int hesiod_reload P((mnt_map *m, char *map, void (*fn)()));
int hesiod_reload(m, map, fn)
mnt_map *m;
char *map;
void (*fn)();
{
	char *zone_name, *cp;
	short domainlen;
	int status;

#ifdef DEBUG
	dlog("hesiod_reload (%x %s %x)", m, map, fn);
#endif DEBUG
	if (status = res_init()) {
#ifdef DEBUG
		dlog("hesiod_reload: res_init failed with %d", status);
#endif
		return(status);
	}
	_res.retrans = 90;
	hs_map = m;
	domainlen = strlen(hostdomain);
	zone_name = hes_to_bind(map+HES_PREFLEN, "automount");
	if (*zone_name == '.')
		zone_name++;
	hs_domain = zone_name;
	/* Traverse the DNS tree until we find an SOA we can transfer from.
	 (Our initial zone_name is likely to just be a subtree of a
	 real zone). */
	do {
		/* If we can't find any NS records, go up a level in the
		   DNS tree */
		if (hs_get_ns_list(zone_name) == 0 &&
		    hs_zone_transfer(zone_name) == 0)
			return(0);
		/* Move up DNS tree by one component */
		if (cp = strchr(zone_name, '.'))
			zone_name = ++cp;
		else
			break;
	} while (strlen(zone_name) >= domainlen);
#ifdef DEBUG
	dlog("hesiod_reload: Giving up on %s", hs_domain);
#endif
	return(-1);
}

hs_zone_transfer(domain)
char *domain;
{
	int status, len;
	char buf[PACKETSZ];
	/* Want to make sure ansbuf is well alligned */
	long ansbuf[PACKETSZ/sizeof(long)];

#ifdef DEBUG
	dlog("hs_zone_transfer (%s)", domain);
#endif
	if ((len = res_mkquery(QUERY, domain, C_HS, T_AXFR,
			       (char *)NULL, 0, NULL, buf, PACKETSZ)) == -1) {
#ifdef DEBUG
		dlog("hs_zone_transfer: res_mkquery failed");
#endif
		errno = 0;
		return(-1);
	}
	if ((status = hs_res_send(buf, len, (char *)ansbuf, PACKETSZ)) == -1) {
#ifdef DEBUG
	    dlog("hs_zone_transfer: hs_res_send failed.  status %d errno %d",
		 status, errno);
#endif
		errno = 0;
		return(-1);
	}
	return(0);
}

#define hs_server_addr(ns) ((struct in_addr *) nsaddr_list[ns])

hs_res_send(buf, buflen, answer, anslen)
char *buf;
int buflen;
char *answer;
int anslen;
{
	int retry, ns;
	u_short id, len;
	HEADER *hp = (HEADER *) buf;
	struct iovec iov[2];
	static int s = -1;
	int status;
	struct sockaddr_in server;

	soacnt = 0;
	id = hp->id;
	/*
	 * Send request, RETRY times, or until successful
	 */
	for (retry = _res.retry; retry > 0; retry--) {
		for (ns = 0; ns < hs_nscount; ns++) {
			hs_timeout.tv_sec =
				(_res.retrans << (_res.retry - retry))
				/ hs_nscount;
			if (hs_timeout.tv_sec <= 0)
				hs_timeout.tv_sec = 1;
			hs_timeout.tv_usec = 0;
			if (s < 0) {
				s = socket(AF_INET, SOCK_STREAM, 0);
				if (s < 0) {
					continue;
				}
				servernum = ns;
				bcopy(hs_server_addr(ns), &server.sin_addr,
				      sizeof(struct in_addr));
				server.sin_family = AF_INET;
				server.sin_port = htons(NAMESERVER_PORT);
					
				if (connect(s, &server,
					    sizeof(struct sockaddr)) < 0) {
					(void) close(s);
					s = -1;
					continue;
				}
			}
			/*
			 * Send length & message
			 */
			len = htons((u_short)buflen);
			iov[0].iov_base = (caddr_t)&len;
			iov[0].iov_len = sizeof(len);
			iov[1].iov_base = buf;
			iov[1].iov_len = buflen;
			if (writev(s, iov, 2) != sizeof(len) + buflen) {
				(void) close(s);
				s = -1;
				continue;
			}
			status = 0;
			while (s != -1 && soacnt < 2 && status != -2) {
				if ((status =
				     hs_readresp(s, answer, anslen)) == -1) {
					(void) close(s);
					s = -1;
					continue;
				}
			}
			if (status == -2) {
				/* There was a permanent error transfering this
				   zone.  Give up. */
				if (s != -1) {
					(void) close(s);
					s = -1;
				}
				return(-1);
			}
			if (s == -1)
				continue;
			return (0);
		}
	}
	if (errno == 0)
		errno = ETIMEDOUT;
	return (-1);
}

/* Returns:
   0: Success
   -1: Error
   -2: Permanent failure
*/