This commit adds support to ypbind(8) for binding to non-local servers.

The standard SunOS ypbind(8) (and, until now, the FreeBSD ypbind)
only selects servers based on whether or not they respond to clnt_broadcast().
Ypbind(8) broadcasts to the YPPROC_DOMAIN_NONACK procedure and waits
for answers; whichever server answers first is the one ypbind uses
for the local client binding.

This mechanism fails when binding across subnets is desired. In order
for a client on one subnet to bind to a server on another subnet, the
gateway(s) between the client and server must be configured to forward
broadcasts. If this is not possible, then a slave server must be
installed on the remote subnet. If this is also not possible, you
have to force the client to bind to the remote server with ypset(8).

Unfortunately, this last option is less than ideal. If the remote
server becomes unavailable, ypbind(8) will lose its binding and
revert to its broadcast-based search behavior. Even if there are
other servers available, or even if the original server comes back
up, ypbind(8) will not be able to create a new binding since all
the servers are on remote subnets where its broadcasts won't be heard.
If the administrator isn't around to run ypset(8) again, the system
is hosed.

In some Linux NIS implementations, there exists a yp.conf file where
you can explicitly specify a server address and avoid the use of
ypbind altogether. This is not desireable since it removes the
possibility of binding to an alternate server in the event that the
one specified in yp.conf crashes.

Some people have mentioned to me how they though the 'restricted mode'
operation (using the -S flag) could be used as a solution for this
problem since it allows one to specify a list of servers. In fact,
this is not the case: the -S flag just tells ypbind(8) that when it
listens for replies to its broadcasts, it should only honor them if
the replying hosts appear in the specified restricted list.

This behavior has now been changed. If you use the -m flag in conjunction
with the -S flag, ypbind(8) will use a 'many-cast' instead of a broadcast
for choosing a server. In many-cast mode, ypbind(8) will transmit directly
to the YPPROC_DOMAIN_NONACK procedure of all the servers specified in
the restricted mode list and then wait for a reply. As with the broadcast
method, whichever server from the list answers first is used for the
local binding. All other behavior is the same: ypbind(8) continues
to ping its bound server every 60 seconds to insure it's still alive
and will many-cast again if the server fails to respond. The code used
to achieve this is in yp_ping.c; it includes a couple of modified RPC
library routines.

Note that it is not possible to use this mechanism without using
the restricted list since we need to know the addresses of the available
NIS servers ahead of time in order to transmit to them.

Most-recently-requested by: Tom Samplonius

usr.sbin/ypbind/Makefile

@@ -1,6 +1,7 @@
 #	from: @(#)Makefile	5.8 (Berkeley) 7/28/90
-#	$Id$
+#	$Id: Makefile,v 1.4 1997/02/22 16:14:53 peter Exp $
 
+SRCS=	ypbind.c yp_ping.c
 PROG=	ypbind
 MAN8=	ypbind.8
 CFLAGS+=-DDAEMON

usr.sbin/ypbind/yp_ping.c

@@ -0,0 +1,542 @@
+/*
+ * Copyright (c) 1996, 1997
+ *	Bill Paul <wpaul@ctr.columbia.edu>.  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 Bill Paul.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Bill Paul 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 Bill Paul 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.
+ *
+ *	$Id: yp_ping.c,v 1.2 1997/05/25 18:54:11 wpaul Exp wpaul $
+ */
+
+/*
+ * What follows is a special version of clntudp_call() that has been
+ * hacked to send requests and receive replies asynchronously. Similar
+ * magic is used inside rpc.nisd(8) for the special non-blocking,
+ * non-fork()ing, non-threading callback support.
+ */
+
+/*
+ * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
+ * unrestricted use provided that this legend is included on all tape
+ * media and as a part of the software program in whole or part.  Users
+ * may copy or modify Sun RPC without charge, but are not authorized
+ * to license or distribute it to anyone else except as part of a product or
+ * program developed by the user.
+ *
+ * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
+ * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+ *
+ * Sun RPC is provided with no support and without any obligation on the
+ * part of Sun Microsystems, Inc. to assist in its use, correction,
+ * modification or enhancement.
+ *
+ * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+ * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
+ * OR ANY PART THEREOF.
+ *
+ * In no event will Sun Microsystems, Inc. be liable for any lost revenue
+ * or profits or other special, indirect and consequential damages, even if
+ * Sun has been advised of the possibility of such damages.
+ *
+ * Sun Microsystems, Inc.
+ * 2550 Garcia Avenue
+ * Mountain View, California  94043
+ */
+
+#ifndef lint
+/*static char *sccsid = "from: @(#)clnt_udp.c 1.39 87/08/11 Copyr 1984 Sun Micro";*/
+/*static char *sccsid = "from: @(#)clnt_udp.c	2.2 88/08/01 4.0 RPCSRC";*/
+static const char rcsid[] = "@(#) $Id: yp_ping.c,v 1.2 1997/05/25 18:54:11 wpaul Exp wpaul $";
+#endif
+
+/*
+ * clnt_udp.c, Implements a UDP/IP based, client side RPC.
+ *
+ * Copyright (C) 1984, Sun Microsystems, Inc.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <rpc/rpc.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <netdb.h>
+#include <errno.h>
+#include <rpc/pmap_clnt.h>
+#include <rpc/pmap_prot.h>
+#include <rpcsvc/yp.h>
+#include "yp_ping.h"
+
+#ifndef timeradd
+#ifndef KERNEL		/* use timevaladd/timevalsub in kernel */
+/* NetBSD/OpenBSD compatable interfaces */
+#define timeradd(tvp, uvp, vvp)						\
+	do {								\
+		(vvp)->tv_sec = (tvp)->tv_sec + (uvp)->tv_sec;		\
+		(vvp)->tv_usec = (tvp)->tv_usec + (uvp)->tv_usec;	\
+		if ((vvp)->tv_usec >= 1000000) {			\
+			(vvp)->tv_sec++;				\
+			(vvp)->tv_usec -= 1000000;			\
+		}							\
+	} while (0)
+#define timersub(tvp, uvp, vvp)						\
+	do {								\
+		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
+		(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;	\
+		if ((vvp)->tv_usec < 0) {				\
+			(vvp)->tv_sec--;				\
+			(vvp)->tv_usec += 1000000;			\
+		}							\
+	} while (0)
+#endif
+#endif
+
+/*
+ * Private data kept per client handle
+ */
+struct cu_data {
+	int		   cu_sock;
+	bool_t		   cu_closeit;
+	struct sockaddr_in cu_raddr;
+	int		   cu_rlen;
+	struct timeval	   cu_wait;
+	struct timeval     cu_total;
+	struct rpc_err	   cu_error;
+	XDR		   cu_outxdrs;
+	u_int		   cu_xdrpos;
+	u_int		   cu_sendsz;
+	char		   *cu_outbuf;
+	u_int		   cu_recvsz;
+	char		   cu_inbuf[1];
+};
+
+static enum clnt_stat
+clntudp_a_call(cl, proc, xargs, argsp, xresults, resultsp, utimeout)
+	register CLIENT	*cl;		/* client handle */
+	u_long		proc;		/* procedure number */
+	xdrproc_t	xargs;		/* xdr routine for args */
+	caddr_t		argsp;		/* pointer to args */
+	xdrproc_t	xresults;	/* xdr routine for results */
+	caddr_t		resultsp;	/* pointer to results */
+	struct timeval	utimeout;	/* seconds to wait before giving up */
+{
+	register struct cu_data *cu = (struct cu_data *)cl->cl_private;
+	register XDR *xdrs;
+	register int outlen = 0;
+	register int inlen;
+	int fromlen;
+	fd_set *fds, readfds;
+	struct sockaddr_in from;
+	struct rpc_msg reply_msg;
+	XDR reply_xdrs;
+	struct timeval time_waited, start, after, tmp1, tmp2, tv;
+	bool_t ok;
+	int nrefreshes = 2;	/* number of times to refresh cred */
+	struct timeval timeout;
+
+	if (cu->cu_total.tv_usec == -1)
+		timeout = utimeout;     /* use supplied timeout */
+	else
+		timeout = cu->cu_total; /* use default timeout */
+
+	if (cu->cu_sock + 1 > FD_SETSIZE) {
+		int bytes = howmany(cu->cu_sock + 1, NFDBITS) * sizeof(fd_mask);
+		fds = (fd_set *)malloc(bytes);
+		if (fds == NULL)
+			return (cu->cu_error.re_status = RPC_CANTSEND);
+		memset(fds, 0, bytes);
+	} else {
+		fds = &readfds;
+		FD_ZERO(fds);
+	}
+
+	timerclear(&time_waited);
+
+call_again:
+	xdrs = &(cu->cu_outxdrs);
+	if (xargs == NULL)
+		goto get_reply;
+	xdrs->x_op = XDR_ENCODE;
+	XDR_SETPOS(xdrs, cu->cu_xdrpos);
+	/*
+	 * the transaction is the first thing in the out buffer
+	 */
+	(*(u_short *)(cu->cu_outbuf))++;
+	if ((! XDR_PUTLONG(xdrs, (long *)&proc)) ||
+	    (! AUTH_MARSHALL(cl->cl_auth, xdrs)) ||
+	    (! (*xargs)(xdrs, argsp))) {
+		if (fds != &readfds)
+			free(fds);
+		return (cu->cu_error.re_status = RPC_CANTENCODEARGS);
+	}
+	outlen = (int)XDR_GETPOS(xdrs);
+
+send_again:
+	if (sendto(cu->cu_sock, cu->cu_outbuf, outlen, 0,
+	    (struct sockaddr *)&(cu->cu_raddr), cu->cu_rlen) != outlen) {
+		cu->cu_error.re_errno = errno;
+		if (fds != &readfds)
+			free(fds);
+		return (cu->cu_error.re_status = RPC_CANTSEND);
+	}
+
+	/*
+	 * Hack to provide rpc-based message passing
+	 */
+	if (!timerisset(&timeout)) {
+		if (fds != &readfds)
+			free(fds);
+		return (cu->cu_error.re_status = RPC_TIMEDOUT);
+	}
+
+get_reply:
+
+	/*
+	 * sub-optimal code appears here because we have
+	 * some clock time to spare while the packets are in flight.
+	 * (We assume that this is actually only executed once.)
+	 */
+	reply_msg.acpted_rply.ar_verf = _null_auth;
+	reply_msg.acpted_rply.ar_results.where = resultsp;
+	reply_msg.acpted_rply.ar_results.proc = xresults;
+
+	gettimeofday(&start, NULL);
+	for (;;) {
+		/* XXX we know the other bits are still clear */
+		FD_SET(cu->cu_sock, fds);
+		tv = cu->cu_wait;
+		switch (select(cu->cu_sock+1, fds, NULL, NULL, &tv)) {
+
+		case 0:
+			timeradd(&time_waited, &cu->cu_wait, &tmp1);
+			time_waited = tmp1;
+			if (timercmp(&time_waited, &timeout, <))
+				goto send_again;
+			if (fds != &readfds)
+				free(fds);
+			return (cu->cu_error.re_status = RPC_TIMEDOUT);
+
+		case -1:
+			if (errno == EINTR) {
+				gettimeofday(&after, NULL);
+				timersub(&after, &start, &tmp1);
+				timeradd(&time_waited, &tmp1, &tmp2);
+				time_waited = tmp2;
+				if (timercmp(&time_waited, &timeout, <))
+					continue;
+				if (fds != &readfds)
+					free(fds);
+				return (cu->cu_error.re_status = RPC_TIMEDOUT);
+			}
+			cu->cu_error.re_errno = errno;
+			if (fds != &readfds)
+				free(fds);
+			return (cu->cu_error.re_status = RPC_CANTRECV);
+		}
+
+		do {
+			fromlen = sizeof(struct sockaddr);
+			inlen = recvfrom(cu->cu_sock, cu->cu_inbuf,
+				(int) cu->cu_recvsz, 0,
+				(struct sockaddr *)&from, &fromlen);
+		} while (inlen < 0 && errno == EINTR);
+		if (inlen < 0) {
+			if (errno == EWOULDBLOCK)
+				continue;
+			cu->cu_error.re_errno = errno;
+			if (fds != &readfds)
+				free(fds);
+			return (cu->cu_error.re_status = RPC_CANTRECV);
+		}
+		if (inlen < sizeof(u_int32_t))
+			continue;
+#ifdef dont_check_xid
+		/* see if reply transaction id matches sent id */
+		if (*((u_int32_t *)(cu->cu_inbuf)) != *((u_int32_t *)(cu->cu_outbuf)))
+			continue;
+#endif
+		/* we now assume we have the proper reply */
+		break;
+	}
+
+	/*
+	 * now decode and validate the response
+	 */
+	xdrmem_create(&reply_xdrs, cu->cu_inbuf, (u_int)inlen, XDR_DECODE);
+	ok = xdr_replymsg(&reply_xdrs, &reply_msg);
+	/* XDR_DESTROY(&reply_xdrs);  save a few cycles on noop destroy */
+	if (ok) {
+		_seterr_reply(&reply_msg, &(cu->cu_error));
+		if (cu->cu_error.re_status == RPC_SUCCESS) {
+			if (! AUTH_VALIDATE(cl->cl_auth,
+				&reply_msg.acpted_rply.ar_verf)) {
+				cu->cu_error.re_status = RPC_AUTHERROR;
+				cu->cu_error.re_why = AUTH_INVALIDRESP;
+			}
+			if (reply_msg.acpted_rply.ar_verf.oa_base != NULL) {
+				xdrs->x_op = XDR_FREE;
+				(void)xdr_opaque_auth(xdrs,
+				    &(reply_msg.acpted_rply.ar_verf));
+			}
+		}  /* end successful completion */
+		else {
+			/* maybe our credentials need to be refreshed ... */
+			if (nrefreshes > 0 && AUTH_REFRESH(cl->cl_auth)) {
+				nrefreshes--;
+				goto call_again;
+			}
+		}  /* end of unsuccessful completion */
+	}  /* end of valid reply message */
+	else {
+		cu->cu_error.re_status = RPC_CANTDECODERES;
+	}
+	if (fds != &readfds)
+		free(fds);
+	return (cu->cu_error.re_status);
+}
+
+
+/*
+ * pmap_getport.c
+ * Client interface to pmap rpc service.
+ *
+ * Copyright (C) 1984, Sun Microsystems, Inc.
+ */
+
+
+static struct timeval timeout = { 1, 0 };
+static struct timeval tottimeout = { 1, 0 };
+
+/*
+ * Find the mapped port for program,version.
+ * Calls the pmap service remotely to do the lookup.
+ * Returns 0 if no map exists.
+ */
+static u_short
+__pmap_getport(address, program, version, protocol)
+	struct sockaddr_in *address;
+	u_long program;
+	u_long version;
+	u_int protocol;
+{
+	u_short port = 0;
+	int sock = -1;
+	register CLIENT *client;
+	struct pmap parms;
+
+	address->sin_port = htons(PMAPPORT);
+
+	client = clntudp_bufcreate(address, PMAPPROG,
+	    PMAPVERS, timeout, &sock, RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
+	if (client != (CLIENT *)NULL) {
+		parms.pm_prog = program;
+		parms.pm_vers = version;
+		parms.pm_prot = protocol;
+		parms.pm_port = 0;  /* not needed or used */
+		if (CLNT_CALL(client, PMAPPROC_GETPORT, xdr_pmap, &parms,
+		    xdr_u_short, &port, tottimeout) != RPC_SUCCESS){
+			rpc_createerr.cf_stat = RPC_PMAPFAILURE;
+			clnt_geterr(client, &rpc_createerr.cf_error);
+		} else if (port == 0) {
+			rpc_createerr.cf_stat = RPC_PROGNOTREGISTERED;
+		}
+		CLNT_DESTROY(client);
+	}
+	if (sock != -1)
+		(void)close(sock);
+	address->sin_port = 0;
+	return (port);
+}
+
+/*
+ * Transmit to YPPROC_DOMAIN_NONACK, return immediately.
+ */
+static bool_t *
+ypproc_domain_nonack_2_send(domainname *argp, CLIENT *clnt)
+{
+	static bool_t clnt_res;
+	struct timeval TIMEOUT = { 0, 0 };
+
+	memset((char *)&clnt_res, 0, sizeof (clnt_res));
+	if (clnt_call(clnt, YPPROC_DOMAIN_NONACK,
+		(xdrproc_t) xdr_domainname, (caddr_t) argp,
+		(xdrproc_t) xdr_bool, (caddr_t) &clnt_res,
+		TIMEOUT) != RPC_SUCCESS) {
+		return (NULL);
+	}
+	return (&clnt_res);
+}
+
+/*
+ * Receive response from YPPROC_DOMAIN_NONACK asynchronously.
+ */
+static bool_t *
+ypproc_domain_nonack_2_recv(domainname *argp, CLIENT *clnt)
+{
+	static bool_t clnt_res;
+	struct timeval TIMEOUT = { 0, 0 };
+
+	memset((char *)&clnt_res, 0, sizeof (clnt_res));
+	if (clnt_call(clnt, YPPROC_DOMAIN_NONACK,
+		(xdrproc_t) NULL, (caddr_t) argp,
+		(xdrproc_t) xdr_bool, (caddr_t) &clnt_res,
+		TIMEOUT) != RPC_SUCCESS) {
+		return (NULL);
+	}
+	return (&clnt_res);
+}
+
+/*
+ * "We have the machine that goes 'ping!'" -- Monty Python
+ *
+ * This function blasts packets at the YPPROC_DOMAIN_NONACK procedures
+ * of the NIS servers listed in restricted_addrs structure.
+ * Whoever replies the fastest becomes our chosen server.
+ *
+ * Note: THIS IS NOT A BROADCAST OPERATION! We could use clnt_broadcast()
+ * for this, but that has the following problems:
+ * - We only get the address of the machine that replied in the
+ *   'eachresult' callback, and on multi-homed machines this can
+ *   lead to confusion.
+ * - clnt_broadcast() only transmits to local networks, whereas with
+ *   NIS+ you can have a perfectly good server located anywhere on or
+ *   off the local network.
+ * - clnt_broadcast() blocks for an arbitrary amount of time which the
+ *   caller can't control -- we want to avoid that.
+ *
+ * Also note that this has nothing to do with the NIS_PING procedure used
+ * for replica updates.
+ */
+
+struct ping_req {
+	struct sockaddr_in	sin;
+	unsigned long		xid;
+};
+
+int __yp_ping(restricted_addrs, cnt, dom, port)
+	struct in_addr		*restricted_addrs;
+	int			cnt;
+	char			*dom;
+	short			*port;
+{
+	struct timeval		tv = { 5 , 0 };
+	struct ping_req		**reqs;
+	unsigned long		i;
+	struct sockaddr_in	sin, *any;
+	int			winner = -1;
+	time_t			xid_seed, xid_lookup;
+	int			sock, dontblock = 1;
+	CLIENT			*clnt;
+	char			*foo = dom;
+	struct cu_data		*cu;
+	enum clnt_stat		(*oldfunc)();
+
+	/* Set up handles. */
+	reqs = calloc(1, sizeof(struct ping_req *) * cnt);
+	xid_seed = time(NULL) ^ getpid();
+
+	for (i = 0; i < cnt; i++) {
+		bzero((char *)&sin, sizeof(sin));
+		sin.sin_family = AF_INET;
+		bcopy((char *)&restricted_addrs[i],
+			(char *)&sin.sin_addr, sizeof(struct in_addr));
+		sin.sin_port = htons(__pmap_getport(&sin, YPPROG,
+					YPVERS, IPPROTO_UDP));
+		if (sin.sin_port == 0)
+			continue;
+		reqs[i] = calloc(1, sizeof(struct ping_req));
+		bcopy((char *)&sin, (char *)&reqs[i]->sin, sizeof(sin));
+		any = &reqs[i]->sin;
+		reqs[i]->xid = xid_seed;
+		xid_seed++;
+	}
+
+	/* Make sure at least one server was assigned */
+	if (reqs[0] == NULL) {
+		free(reqs);
+		return(-1);
+	}
+
+	/* Create RPC handle */
+	sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	clnt = clntudp_create(any, YPPROG, YPVERS, tv, &sock);
+	if (clnt == NULL) {
+		close(sock);
+		for (i = 0; i < cnt; i++)
+			if (reqs[i] != NULL)
+				free(reqs[i]);
+		free(reqs);
+		return(-1);
+	}
+	clnt->cl_auth = authunix_create_default();
+	cu = (struct cu_data *)clnt->cl_private;
+	tv.tv_sec = 0;
+	clnt_control(clnt, CLSET_TIMEOUT, &tv);
+	ioctl(sock, FIONBIO, &dontblock);
+	oldfunc = clnt->cl_ops->cl_call;
+	clnt->cl_ops->cl_call = clntudp_a_call;
+
+	/* Transmit */
+	for (i = 0; i < cnt; i++) {
+		if (reqs[i] != NULL) {
+			/* subtract one; clntudp_call() will increment */
+			*((u_int32_t *)(cu->cu_outbuf)) = reqs[i]->xid - 1;
+			bcopy((char *)&reqs[i]->sin, (char *)&cu->cu_raddr,
+				sizeof(struct sockaddr_in));
+			ypproc_domain_nonack_2_send(&foo, clnt);
+		}
+	}
+
+	/* Receive reply */
+	ypproc_domain_nonack_2_recv(&foo, clnt);
+
+	/* Got a winner -- look him up. */
+	xid_lookup = *((u_int32_t *)(cu->cu_inbuf));
+	for (i = 0; i < cnt; i++) {
+		if (reqs[i] != NULL && reqs[i]->xid == xid_lookup) {
+			winner = i;
+			*port = reqs[i]->sin.sin_port;
+		}
+	}
+
+	/* Shut everything down */
+	clnt->cl_ops->cl_call = oldfunc;
+	auth_destroy(clnt->cl_auth);
+	clnt_destroy(clnt);
+	close(sock);
+
+	for (i = 0; i < cnt; i++)
+		if (reqs[i] != NULL)
+			free(reqs[i]);
+	free(reqs);
+
+	return(winner);
+}

usr.sbin/ypbind/yp_ping.h

@@ -0,0 +1 @@
+extern int __yp_ping __P(( struct in_addr *, int, char *, short * ));

usr.sbin/ypbind/ypbind.8

@@ -29,7 +29,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$Id: ypbind.8,v 1.8 1997/02/22 16:14:54 peter Exp $
+.\"	$Id: ypbind.8,v 1.9 1997/04/15 07:15:47 jmg Exp $
 .\"
 .Dd April 9, 1995
 .Dt YPBIND 8
@@ -42,6 +42,7 @@
 .Op Fl ypset
 .Op Fl ypsetme
 .Op Fl s
+.Op Fl m
 .Op Fl S Ar domainname,server1,server2,...
 .Sh DESCRIPTION
 .Nm
@@ -134,6 +135,24 @@ Note that
 will consider the domainname specified with the
 .Fl S
 flag to be the system default domain.
+.It Fl m
+The
+.Fl m
+flag can only be used in conjunction with the
+.Fl S
+flag above (if used without the
+.Fl S
+flag, it has no effect). It causes
+.Nm ypbind
+to use a 'many-cast' rather than a broadcast for choosing a server
+from the restricted mode server list. In many-cast mode,
+.Nm ypbind
+will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the
+servers specified in the restricted list and bind to the server that
+responds the fastest.
+This mode of operation is useful for NIS clients on remote subnets
+where no local NIS servers are available.
+.El
 .Sh NOTES
 The
 .Nm

usr.sbin/ypbind/ypbind.c

@@ -28,7 +28,7 @@
  */
 
 #ifndef LINT
-static char rcsid[] = "$Id: ypbind.c,v 1.23 1997/02/22 16:14:56 peter Exp $";
+static char rcsid[] = "$Id: ypbind.c,v 1.24 1997/04/10 14:18:03 wpaul Exp $";
 #endif
 
 #include <sys/param.h>
@@ -61,6 +61,7 @@ static char rcsid[] = "$Id: ypbind.c,v 1.23 1997/02/22 16:14:56 peter Exp $";
 #include <rpcsvc/yp.h>
 struct dom_binding{};
 #include <rpcsvc/ypclnt.h>
+#include "yp_ping.h"
 
 #ifndef BINDINGDIR
 #define BINDINGDIR "/var/yp/binding"
@@ -121,6 +122,7 @@ int ppid;
  */
 #define RESTRICTED_SERVERS 10
 int yp_restricted = 0;
+int yp_manycast = 0;
 struct in_addr restricted_addrs[RESTRICTED_SERVERS];
 
 /* No more than MAX_CHILDREN child broadcasters at a time. */
@@ -417,6 +419,8 @@ char **argv;
 		        ypsecuremode++;
 		else if (strcmp("-S", argv[i]) == 0 && argc > i)
 			yp_restricted_mode(argv[i+1]);
+		else if (strcmp("-m", argv[i]) == 0)
+			yp_manycast++;
 	}
 
 	/* blow away everything in BINDINGDIR (if it exists) */
@@ -711,6 +715,40 @@ struct _dom_binding *ypdb;
 	}
 	close(yplockfd);
 
+	/*
+	 * Special 'many-cast' behavior. If we're in restricted mode,
+	 * we have a list of possible server addresses to try. What
+	 * we can do is transmit to each ypserv's YPPROC_DOMAIN_NONACK
+	 * procedure and time the replies. Whoever replies fastest
+	 * gets to be our server. Note that this is not a broadcast
+	 * operation: we transmit uni-cast datagrams only.
+	 */
+	if (yp_restricted && yp_manycast) {
+		short			port;
+		int			i;
+		struct sockaddr_in	sin;
+
+		i = __yp_ping(restricted_addrs, yp_restricted,
+				ypdb->dom_domain, &port);
+		if (i == -1) {
+			bzero((char *)&ypdb->dom_server_addr,
+						sizeof(struct sockaddr_in));
+			if (tell_parent(ypdb->dom_domain,
+					&ypdb->dom_server_addr))
+			syslog(LOG_WARNING, "lost connection to parent");
+		} else {
+			bzero((char *)&sin, sizeof(struct sockaddr_in));
+			bcopy((char *)&restricted_addrs[i],
+				(char *)&sin.sin_addr, sizeof(struct in_addr));
+			sin.sin_family = AF_INET;
+			sin.sin_port = port;
+			if (tell_parent(broad_domain->dom_domain, &sin))
+				syslog(LOG_WARNING,
+					"lost connection to parent");
+		}
+		_exit(0);
+	}
+
 	retries = 0;
 
 	{
@@ -729,7 +767,7 @@ struct _dom_binding *ypdb;
 			syslog(LOG_WARNING, "lost connection to parent");
 	}
 
-	exit(0);
+	_exit(0);
 }
 
 /*
@@ -981,6 +1019,6 @@ char *args;
 	/* ypset and ypsetme not allowed with restricted mode */
 	ypsetmode = YPSET_NO;
 	
-	yp_restricted = 1;
+	yp_restricted = i;
 	return;
 }