xref: /illumos-gate/usr/src/lib/libnsl/nss/netdir_inet.c (revision d81a47b3)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2012 Milan Jurik. All rights reserved.
 */

/*
 * This is where we have chosen to combine every useful bit of code for
 * all the Solaris frontends to lookup hosts, services, and netdir information
 * for inet family (udp, tcp) transports. gethostbyYY(), getservbyYY(), and
 * netdir_getbyYY() are all implemented on top of this code. Similarly,
 * netdir_options, taddr2uaddr, and uaddr2taddr for inet transports also
 * find a home here.
 *
 * If the netconfig structure supplied has NO nametoaddr libs (i.e. a "-"
 * in /etc/netconfig), this code calls the name service switch, and
 * therefore, /etc/nsswitch.conf is effectively the only place that
 * dictates hosts/serv lookup policy.
 * If an administrator chooses to bypass the name service switch by
 * specifying third party supplied nametoaddr libs in /etc/netconfig, this
 * implementation does NOT call the name service switch, it merely loops
 * through the nametoaddr libs. In this case, if this code was called
 * from gethost/servbyYY() we marshal the inet specific struct into
 * transport independent netbuf or hostserv, and unmarshal the resulting
 * nd_addrlist or hostservlist back into hostent and servent, as the case
 * may be.
 *
 * Goes without saying that most of the future bugs in gethost/servbyYY
 * and netdir_getbyYY are lurking somewhere here.
 */

#include "mt.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stropts.h>
#include <sys/types.h>
#include <sys/byteorder.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/time.h>
#include <errno.h>
#include <fcntl.h>
#include <thread.h>
#include <synch.h>
#include <sys/utsname.h>
#include <netdb.h>
#include <netconfig.h>
#include <netdir.h>
#include <tiuser.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <inet/ip.h>
#include <inet/ip6_asp.h>
#include <sys/dlpi.h>
#include <nss_dbdefs.h>
#include <nss_netdir.h>
#include <syslog.h>
#include <nsswitch.h>
#include "nss.h"

#define	MAXIFS 32
#define	UDPDEV	"/dev/udp"
#define	UDP6DEV	"/dev/udp6"

#define	DOOR_GETHOSTBYNAME_R	_switch_gethostbyname_r
#define	DOOR_GETHOSTBYADDR_R	_switch_gethostbyaddr_r
#define	DOOR_GETIPNODEBYNAME_R	_switch_getipnodebyname_r
#define	DOOR_GETIPNODEBYADDR_R	_switch_getipnodebyaddr_r

#define	DONT_SORT	"SORT_ADDRS=NO"
#define	DONT_SORT2	"SORT_ADDRS=FALSE"
#define	LINESIZE	100

/*
 * constant values of addresses for HOST_SELF_BIND, HOST_SELF_CONNECT
 * and localhost.
 *
 * The following variables are static to the extent that they should
 * not be visible outside of this file.
 */
static char *localaddr[] = {"\000\000\000\000", NULL};
static char *connectaddr[] = {"\177\000\000\001", NULL};
static char *localaddr6[] =
{"\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", NULL};
static char *connectaddr6[] =
{"\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\001", NULL};

/* IPv4 nd_addrlist */
static mutex_t	nd_addr_lock = DEFAULTMUTEX;
static struct sockaddr_in sa_con;
static struct netbuf nd_conbuf = {sizeof (sa_con),\
    sizeof (sa_con), (char *)&sa_con};
static struct nd_addrlist nd_conaddrlist = {1, &nd_conbuf};

/* IPv6 nd_addrlist */
static mutex_t	nd6_addr_lock = DEFAULTMUTEX;
static struct sockaddr_in6 sa6_con;
static struct netbuf nd6_conbuf = {sizeof (sa6_con),\
	sizeof (sa6_con), (char *)&sa6_con};
static struct nd_addrlist nd6_conaddrlist = {1, &nd6_conbuf};

#define	LOCALHOST "localhost"

struct servent *_switch_getservbyname_r(const char *, const char *,
    struct servent *, char *, int);
struct servent *_switch_getservbyport_r(int, const char *, struct servent *,
    char *, int);

static int __herrno2netdir(int h_errnop);
static struct ifinfo *get_local_info(void);
static int getbroadcastnets(struct netconfig *, struct in_addr **);
static int hent2ndaddr(int, char **, int *, struct nd_addrlist **);
static int ndaddr2hent(int, const char *, struct nd_addrlist *,
    struct hostent *, char *, int);
static int hsents2ndhostservs(struct hostent *, struct servent *, ushort_t,
    struct nd_hostservlist **);
static int ndaddr2srent(const char *, const char *, ushort_t, struct servent *,
    char *, int);
static int ndhostserv2hent(struct netbuf *, struct nd_hostservlist *,
    struct hostent *, char *, int);
static int ndhostserv2srent(int, const char *, struct nd_hostservlist *,
    struct servent *, char *, int);
static int nd2herrno(int nerr);
static void order_haddrlist_inet(char **haddrlist, size_t addrcount);
static void order_haddrlist_inet6(char **haddrlist, size_t addrcount);
static int dstcmp(const void *, const void *);
static int nss_strioctl(int af, int cmd, void *ptr, int ilen);
static struct in_addr _inet_makeaddr(in_addr_t, in_addr_t);
static boolean_t _read_nsw_file(void);

/*
 * Begin: PART I
 * Top Level Interfaces that gethost/serv/netdir funnel through.
 */

static int
inetdir_free(int ret, struct in_addr *inaddrs, char **baddrlist)
{
	if (inaddrs)
		free(inaddrs);
	if (baddrlist)
		free(baddrlist);
	_nderror = ret;
	return (ret);
}

/*
 * gethost/servbyname always call this function; if they call
 * with nametoaddr libs in nconf, we call netdir_getbyname
 * implementation: __classic_netdir_getbyname, otherwise nsswitch.
 *
 * netdir_getbyname calls this only if nametoaddr libs are NOT
 * specified for inet transports; i.e. it's supposed to follow
 * the name service switch.
 */
int
_get_hostserv_inetnetdir_byname(struct netconfig *nconf,
    struct nss_netdirbyname_in *args, union nss_netdirbyname_out *res)
{
	int	server_port;
	int *servp = &server_port;
	char	**haddrlist;
	uint32_t dotnameaddr;
	char	*dotnamelist[2];
	struct in_addr	*inaddrs = NULL;
	struct in6_addr	v6nameaddr;
	char	**baddrlist = NULL;

	if (nconf == NULL) {
		_nderror = ND_BADARG;
		return (ND_BADARG);
	}

	/*
	 * 1. gethostbyname()/netdir_getbyname() special cases:
	 */
	switch (args->op_t) {

		case NSS_HOST:
		/*
		 * Worth the performance gain -- assuming a lot of inet apps
		 * actively use "localhost".
		 */
		if (strcmp(args->arg.nss.host.name, LOCALHOST) == 0) {

			(void) mutex_lock(&nd_addr_lock);
			IN_SET_LOOPBACK_ADDR(&sa_con);
			_nderror = ndaddr2hent(AF_INET, args->arg.nss.host.name,
			    &nd_conaddrlist, res->nss.host.hent,
			    args->arg.nss.host.buf,
			    args->arg.nss.host.buflen);
			(void) mutex_unlock(&nd_addr_lock);
			if (_nderror != ND_OK)
				*(res->nss.host.herrno_p) =
				    nd2herrno(_nderror);
			return (_nderror);
		}
		/*
		 * If the caller passed in a dot separated IP notation to
		 * gethostbyname, return that back as the address.
		 * The nd_addr_lock mutex was added to be truely re-entrant.
		 */
		if (inet_aton(args->arg.nss.host.name,
		    (struct in_addr *)&dotnameaddr)) {
			(void) mutex_lock(&nd_addr_lock);
			(void) memset(&sa_con, 0, sizeof (sa_con));
			sa_con.sin_family = AF_INET;
			sa_con.sin_addr.s_addr = dotnameaddr;
			_nderror = ndaddr2hent(AF_INET, args->arg.nss.host.name,
			    &nd_conaddrlist, res->nss.host.hent,
			    args->arg.nss.host.buf,
			    args->arg.nss.host.buflen);
			(void) mutex_unlock(&nd_addr_lock);
			if (_nderror != ND_OK)
				*(res->nss.host.herrno_p) =
				    nd2herrno(_nderror);
			return (_nderror);
		}
		break;

		case NSS_HOST6:
		/*
		 * Handle case of literal address string.
		 */
		if (strchr(args->arg.nss.host6.name, ':') != NULL &&
		    (inet_pton(AF_INET6, args->arg.nss.host6.name,
		    &v6nameaddr) != 0)) {
			int	ret;

			(void) mutex_lock(&nd6_addr_lock);
			(void) memset(&sa6_con, 0, sizeof (sa6_con));
			sa6_con.sin6_family = AF_INET6;
			(void) memcpy(&(sa6_con.sin6_addr.s6_addr),
			    &v6nameaddr, sizeof (struct in6_addr));
			ret = ndaddr2hent(AF_INET6,
			    args->arg.nss.host6.name,
			    &nd6_conaddrlist, res->nss.host.hent,
			    args->arg.nss.host6.buf,
			    args->arg.nss.host6.buflen);
			(void) mutex_unlock(&nd6_addr_lock);
			if (ret != ND_OK)
				*(res->nss.host.herrno_p) = nd2herrno(ret);
			else
				res->nss.host.hent->h_aliases = NULL;
			return (ret);
		}
		break;

		case NETDIR_BY:
			if (args->arg.nd_hs == 0) {
				_nderror = ND_BADARG;
				return (ND_BADARG);
			}
			/*
			 * If servname is NULL, return 0 as the port number
			 * If servname is rpcbind, return 111 as the port number
			 * If servname is a number, return it back as the port
			 * number.
			 */
			if (args->arg.nd_hs->h_serv == 0) {
				*servp = htons(0);
			} else if (strcmp(args->arg.nd_hs->h_serv,
			    "rpcbind") == 0) {
				*servp = htons(111);
			} else if (strspn(args->arg.nd_hs->h_serv,
			    "0123456789") ==
			    strlen(args->arg.nd_hs->h_serv)) {
				*servp = htons(atoi(args->arg.nd_hs->h_serv));
			} else {
				/* i.e. need to call a name service on this */
				servp = NULL;
			}

			/*
			 * If the hostname is HOST_SELF_BIND, we return 0.0.0.0
			 * so the  binding can be contacted through all
			 * interfaces. If the hostname is HOST_SELF_CONNECT,
			 * we return 127.0.0.1 so the address can be connected
			 * to locally. If the hostname is HOST_ANY, we return
			 * no addresses because IP doesn't know how to specify
			 * a service without a host. And finally if we specify
			 * HOST_BROADCAST then we ask a tli fd to tell us what
			 * the broadcast addresses are for any udp
			 * interfaces on this machine.
			 */
			if (args->arg.nd_hs->h_host == 0) {
				_nderror = ND_NOHOST;
				return (ND_NOHOST);
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    HOST_SELF_BIND) == 0)) {
				haddrlist = localaddr;
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    HOST_SELF_CONNECT) == 0)) {
				haddrlist = connectaddr;
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    LOCALHOST) == 0)) {
				haddrlist = connectaddr;
			} else if ((int)(dotnameaddr =
			    inet_addr(args->arg.nd_hs->h_host)) != -1) {
				/*
				 * If the caller passed in a dot separated IP
				 * notation to netdir_getbyname, convert that
				 * back into address.
				 */

				dotnamelist[0] = (char *)&dotnameaddr;
				dotnamelist[1] = NULL;
				haddrlist = dotnamelist;
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    HOST_BROADCAST) == 0)) {
				/*
				 * Now that inaddrs and baddrlist are
				 * dynamically allocated, care must be
				 * taken in freeing up the
				 * memory at each 'return()' point.
				 *
				 * Early return protection (using
				 * inetdir_free()) is needed only in NETDIR_BY
				 * cases because dynamic allocation is used
				 * when args->op_t == NETDIR_BY.
				 *
				 * Early return protection is not needed in
				 * haddrlist==0 conditionals because dynamic
				 * allocation guarantees haddrlist!=0.
				 *
				 * Early return protection is not needed in most
				 * servp!=0 conditionals because this is handled
				 * (and returned) first.
				 */
				int i, bnets;

				bnets = getbroadcastnets(nconf, &inaddrs);
				if (bnets == 0) {
					_nderror = ND_NOHOST;
					return (ND_NOHOST);
				}
				baddrlist = malloc((bnets+1)*sizeof (char *));
				if (baddrlist == NULL)
					return (inetdir_free(ND_NOMEM, inaddrs,
					    baddrlist));
				for (i = 0; i < bnets; i++)
					baddrlist[i] = (char *)&inaddrs[i];
				baddrlist[i] = NULL;
				haddrlist = baddrlist;
			} else {
				/* i.e. need to call a name service on this */
				haddrlist = 0;
			}

			if (haddrlist && servp) {
				int ret;
				/*
				 * Convert h_addr_list into nd_addrlist.
				 * malloc's will be done, freed using
				 * netdir_free.
				 */
				ret = hent2ndaddr(AF_INET, haddrlist, servp,
				    res->nd_alist);
				return (inetdir_free(ret, inaddrs, baddrlist));
			}
			break;


		case NETDIR_BY6:
			if (args->arg.nd_hs == 0) {
				_nderror = ND_BADARG;
				return (ND_BADARG);
			}
			/*
			 * If servname is NULL, return 0 as the port number.
			 * If servname is rpcbind, return 111 as the port number
			 * If servname is a number, return it back as the port
			 * number.
			 */
			if (args->arg.nd_hs->h_serv == 0) {
				*servp = htons(0);
			} else if (strcmp(args->arg.nd_hs->h_serv,
			    "rpcbind") == 0) {
				*servp = htons(111);
			} else if (strspn(args->arg.nd_hs->h_serv, "0123456789")
			    == strlen(args->arg.nd_hs->h_serv)) {
				*servp = htons(atoi(args->arg.nd_hs->h_serv));
			} else {
				/* i.e. need to call a name service on this */
				servp = NULL;
			}

			/*
			 * If the hostname is HOST_SELF_BIND, we return ipv6
			 * localaddress so the binding can be contacted through
			 * all interfaces.
			 * If the hostname is HOST_SELF_CONNECT, we return
			 * ipv6 loopback address so the address can be connected
			 * to locally.
			 * If the hostname is HOST_ANY, we return no addresses
			 * because IP doesn't know how to specify a service
			 * without a host.
			 * And finally if we specify HOST_BROADCAST then we
			 * disallow since IPV6 does not have any
			 * broadcast concept.
			 */
			if (args->arg.nd_hs->h_host == 0) {
				return (ND_NOHOST);
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    HOST_SELF_BIND) == 0)) {
				haddrlist = localaddr6;
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    HOST_SELF_CONNECT) == 0)) {
				haddrlist = connectaddr6;
			} else if ((strcmp(args->arg.nd_hs->h_host,
			    LOCALHOST) == 0)) {
				haddrlist = connectaddr6;
			} else if (strchr(args->arg.nd_hs->h_host, ':')
			    != NULL) {

			/*
			 * If the caller passed in a dot separated IP notation
			 * to netdir_getbyname, convert that back into address.
			 */

				if ((inet_pton(AF_INET6,
				    args->arg.nd_hs->h_host,
				    &v6nameaddr)) != 0) {
					dotnamelist[0] = (char *)&v6nameaddr;
					dotnamelist[1] = NULL;
					haddrlist = dotnamelist;
				}
				else
					/* not sure what to return */
					return (ND_NOHOST);

			} else if ((strcmp(args->arg.nd_hs->h_host,
			    HOST_BROADCAST) == 0)) {
				/*
				 * Don't support broadcast in
				 * IPV6
				 */
				return (ND_NOHOST);
			} else {
				/* i.e. need to call a name service on this */
				haddrlist = 0;
			}

			if (haddrlist && servp) {
				int ret;
				/*
				 * Convert h_addr_list into nd_addrlist.
				 * malloc's will be done, freed
				 * using netdir_free.
				 */
				ret = hent2ndaddr(AF_INET6, haddrlist,
				    servp, res->nd_alist);
				return (inetdir_free(ret, inaddrs, baddrlist));
			}
			break;


	}

	/*
	 * 2. Most common scenario. This is the way we ship /etc/netconfig.
	 *    Emphasis on improving performance in the "if" part.
	 */
	if (nconf->nc_nlookups == 0) {
		struct hostent	*he = NULL, *tmphe;
		struct servent	*se;
		int	ret;
		nss_XbyY_buf_t	*ndbuf4switch = 0;

	switch (args->op_t) {

		case NSS_HOST:

		he = DOOR_GETHOSTBYNAME_R(args->arg.nss.host.name,
		    res->nss.host.hent, args->arg.nss.host.buf,
		    args->arg.nss.host.buflen,
		    res->nss.host.herrno_p);
		if (he == NULL)
			return (_nderror = ND_NOHOST);
		return (_nderror = ND_OK);

		case NSS_HOST6:

		he = DOOR_GETIPNODEBYNAME_R(args->arg.nss.host6.name,
		    res->nss.host.hent, args->arg.nss.host.buf,
		    args->arg.nss.host6.buflen,
		    args->arg.nss.host6.af_family,
		    args->arg.nss.host6.flags,
		    res->nss.host.herrno_p);

		if (he == NULL)
			return (_nderror = ND_NOHOST);
		return (_nderror = ND_OK);

		case NSS_SERV:

		se = _switch_getservbyname_r(args->arg.nss.serv.name,
		    args->arg.nss.serv.proto,
		    res->nss.serv, args->arg.nss.serv.buf,
		    args->arg.nss.serv.buflen);

		_nderror = ND_OK;
		if (se == 0)
			_nderror = ND_NOSERV;
		return (_nderror);

		case NETDIR_BY:

		if (servp == 0) {
			char	*proto = (strcmp(nconf->nc_proto,
			    NC_TCP) == 0) ? NC_TCP : NC_UDP;

			/*
			 * We go through all this for just one port number,
			 * which is most often constant. How about linking in
			 * an indexed database of well-known ports in the name
			 * of performance ?
			 */
			ndbuf4switch = _nss_XbyY_buf_alloc(
			    sizeof (struct servent), NSS_BUFLEN_SERVICES);
			if (ndbuf4switch == 0)
				return (inetdir_free(ND_NOMEM, inaddrs,
				    baddrlist));
			se = _switch_getservbyname_r(args->arg.nd_hs->h_serv,
			    proto, ndbuf4switch->result,
			    ndbuf4switch->buffer, ndbuf4switch->buflen);
			if (!se) {
				NSS_XbyY_FREE(&ndbuf4switch);
				return (inetdir_free(ND_NOSERV, inaddrs,
				    baddrlist));
			}
			server_port = se->s_port;
			NSS_XbyY_FREE(&ndbuf4switch);
		}

		if (haddrlist == 0) {
			int	h_errnop = 0;

			ndbuf4switch = _nss_XbyY_buf_alloc(
			    sizeof (struct hostent),
			    NSS_BUFLEN_HOSTS);
			if (ndbuf4switch == 0) {
				_nderror = ND_NOMEM;
				return (ND_NOMEM);
			}
			/*
			 * Search the ipnodes (v6) path first,
			 * search will return the v4 addresses
			 * as v4mapped addresses.
			 */
			if ((tmphe = DOOR_GETIPNODEBYNAME_R(
			    args->arg.nd_hs->h_host,
			    ndbuf4switch->result, ndbuf4switch->buffer,
			    ndbuf4switch->buflen, args->arg.nss.host6.af_family,
			    args->arg.nss.host6.flags, &h_errnop)) != NULL)
				he = __mappedtov4(tmphe, &h_errnop);

			if (he == NULL) {
				/* Failover case, try hosts db for v4 address */
				he = DOOR_GETHOSTBYNAME_R(
				    args->arg.nd_hs->h_host,
				    ndbuf4switch->result, ndbuf4switch->buffer,
				    ndbuf4switch->buflen, &h_errnop);
				if (he == NULL) {
					NSS_XbyY_FREE(&ndbuf4switch);
					_nderror = __herrno2netdir(h_errnop);
					return (_nderror);
				}
				/*
				 * Convert h_addr_list into nd_addrlist.
				 * malloc's will be done, freed using
				 * netdir_free.
				 */
				ret = hent2ndaddr(AF_INET, he->h_addr_list,
				    &server_port, res->nd_alist);
			} else {
				/*
				 * Convert h_addr_list into nd_addrlist.
				 * malloc's will be done, freed using
				 * netdir_free.
				 */
				ret = hent2ndaddr(AF_INET, he->h_addr_list,
				    &server_port, res->nd_alist);
				freehostent(he);
			}

			_nderror = ret;
			NSS_XbyY_FREE(&ndbuf4switch);
			return (ret);
		} else {
			int ret;
			/*
			 * Convert h_addr_list into nd_addrlist.
			 * malloc's will be done, freed using netdir_free.
			 */
			ret = hent2ndaddr(AF_INET, haddrlist,
			    &server_port, res->nd_alist);
			return (inetdir_free(ret, inaddrs, baddrlist));
		}


		case NETDIR_BY6:

			if (servp == 0) {
				char	*proto = (strcmp(nconf->nc_proto,
				    NC_TCP) == 0) ? NC_TCP : NC_UDP;

				/*
				 * We go through all this for just
				 * one port number,
				 * which is most often constant.
				 * How about linking in
				 * an indexed database of well-known
				 * ports in the name
				 * of performance ?
				 */
				ndbuf4switch = _nss_XbyY_buf_alloc(
				    sizeof (struct servent),
				    NSS_BUFLEN_SERVICES);
				if (ndbuf4switch == 0)
					return (inetdir_free(ND_NOMEM, inaddrs,
					    baddrlist));
				se = _switch_getservbyname_r(
				    args->arg.nd_hs->h_serv,
				    proto, ndbuf4switch->result,
				    ndbuf4switch->buffer, ndbuf4switch->buflen);
				if (!se) {
					NSS_XbyY_FREE(&ndbuf4switch);
					return (inetdir_free(ND_NOSERV, inaddrs,
					    baddrlist));
				}
				server_port = se->s_port;
				NSS_XbyY_FREE(&ndbuf4switch);
			}

			if (haddrlist == 0) {
				int	h_errnop = 0;

				ndbuf4switch = _nss_XbyY_buf_alloc(
				    sizeof (struct hostent),
				    NSS_BUFLEN_HOSTS);
				if (ndbuf4switch == 0) {
					_nderror = ND_NOMEM;
					return (ND_NOMEM);
				}
				he = DOOR_GETIPNODEBYNAME_R(
				    args->arg.nd_hs->h_host,
				    ndbuf4switch->result, ndbuf4switch->buffer,
				    ndbuf4switch->buflen,
				    args->arg.nss.host6.af_family,
				    args->arg.nss.host6.flags, &h_errnop);
				if (he == NULL) {
					NSS_XbyY_FREE(&ndbuf4switch);
					_nderror = __herrno2netdir(h_errnop);
					return (_nderror);
				}
				/*
				 * Convert h_addr_list into nd_addrlist.
				 * malloc's will be done,
				 * freed using netdir_free.
				 */
				ret = hent2ndaddr(AF_INET6,
				    ((struct hostent *)
				    (ndbuf4switch->result))->h_addr_list,
				    &server_port, res->nd_alist);
				_nderror = ret;
				NSS_XbyY_FREE(&ndbuf4switch);
				return (ret);
			} else {
				int ret;
				/*
				 * Convert h_addr_list into nd_addrlist.
				 * malloc's will be done,
				 * freed using netdir_free.
				 */
				ret = hent2ndaddr(AF_INET6, haddrlist,
				    &server_port, res->nd_alist);
				return (inetdir_free(ret, inaddrs, baddrlist));
			}

		default:
			_nderror = ND_BADARG;
			return (ND_BADARG); /* should never happen */
	}

	} else {
		/* haddrlist is no longer used, so clean up */
		if (inaddrs)
			free(inaddrs);
		if (baddrlist)
			free(baddrlist);
	}

	/*
	 * 3. We come this far only if nametoaddr libs are specified for
	 *    inet transports and we are called by gethost/servbyname only.
	 */
	switch (args->op_t) {
		struct	nd_hostserv service;
		struct	nd_addrlist *addrs;
		int ret;

		case NSS_HOST:

		service.h_host = (char *)args->arg.nss.host.name;
		service.h_serv = NULL;
		if ((_nderror = __classic_netdir_getbyname(nconf,
		    &service, &addrs)) != ND_OK) {
			*(res->nss.host.herrno_p) = nd2herrno(_nderror);
			return (_nderror);
		}
		/*
		 * convert addresses back into sockaddr for gethostbyname.
		 */
		ret = ndaddr2hent(AF_INET, service.h_host, addrs,
		    res->nss.host.hent, args->arg.nss.host.buf,
		    args->arg.nss.host.buflen);
		if (ret != ND_OK)
			*(res->nss.host.herrno_p) = nd2herrno(ret);
		netdir_free((char *)addrs, ND_ADDRLIST);
		_nderror = ret;
		return (ret);

		case NSS_SERV:

		if (args->arg.nss.serv.proto == NULL) {
			/*
			 * A similar HACK showed up in Solaris 2.3.
			 * The caller wild-carded proto -- i.e. will
			 * accept a match using tcp or udp for the port
			 * number. Since we have no hope of getting
			 * directly to a name service switch backend
			 * from here that understands this semantics,
			 * we try calling the netdir interfaces first
			 * with "tcp" and then "udp".
			 */
			args->arg.nss.serv.proto = "tcp";
			_nderror = _get_hostserv_inetnetdir_byname(nconf, args,
			    res);
			if (_nderror != ND_OK) {
				args->arg.nss.serv.proto = "udp";
				_nderror =
				    _get_hostserv_inetnetdir_byname(nconf,
				    args, res);
			}
			return (_nderror);
		}

		/*
		 * Third-parties should optimize their nametoaddr
		 * libraries for the HOST_SELF case.
		 */
		service.h_host = HOST_SELF;
		service.h_serv = (char *)args->arg.nss.serv.name;
		if ((_nderror = __classic_netdir_getbyname(nconf,
		    &service, &addrs)) != ND_OK) {
			return (_nderror);
		}
		/*
		 * convert addresses back into servent for getservbyname.
		 */
		_nderror = ndaddr2srent(service.h_serv,
		    args->arg.nss.serv.proto,
		    /* LINTED pointer cast */
		    ((struct sockaddr_in *)addrs->n_addrs->buf)->sin_port,
		    res->nss.serv,
		    args->arg.nss.serv.buf, args->arg.nss.serv.buflen);
		netdir_free((char *)addrs, ND_ADDRLIST);
		return (_nderror);

		default:
		_nderror = ND_BADARG;
		return (ND_BADARG); /* should never happen */
	}
}

/*
 * gethostbyaddr/servbyport always call this function; if they call
 * with nametoaddr libs in nconf, we call netdir_getbyaddr
 * implementation __classic_netdir_getbyaddr, otherwise nsswitch.
 *
 * netdir_getbyaddr calls this only if nametoaddr libs are NOT
 * specified for inet transports; i.e. it's supposed to follow
 * the name service switch.
 */
int
_get_hostserv_inetnetdir_byaddr(struct netconfig *nconf,
    struct nss_netdirbyaddr_in *args, union nss_netdirbyaddr_out *res)
{
	if (nconf == 0) {
		_nderror = ND_BADARG;
		return (_nderror);
	}

	/*
	 * 1. gethostbyaddr()/netdir_getbyaddr() special cases:
	 */
	switch (args->op_t) {

		case NSS_HOST:
		/*
		 * Worth the performance gain: assuming a lot of inet apps
		 * actively use "127.0.0.1".
		 */
		/* LINTED pointer cast */
		if (*(uint32_t *)(args->arg.nss.host.addr) ==
		    htonl(INADDR_LOOPBACK)) {
			(void) mutex_lock(&nd_addr_lock);
			IN_SET_LOOPBACK_ADDR(&sa_con);
			_nderror = ndaddr2hent(AF_INET, LOCALHOST,
			    &nd_conaddrlist, res->nss.host.hent,
			    args->arg.nss.host.buf,
			    args->arg.nss.host.buflen);
			(void) mutex_unlock(&nd_addr_lock);
			if (_nderror != ND_OK)
				*(res->nss.host.herrno_p) =
				    nd2herrno(_nderror);
			return (_nderror);
		}
		break;

		case NETDIR_BY:
		case NETDIR_BY_NOSRV:
		{
			struct sockaddr_in *sin;

			if (args->arg.nd_nbuf == NULL) {
				_nderror = ND_BADARG;
				return (_nderror);
			}

			/*
			 * Validate the address which was passed
			 * as the request.
			 */
			/* LINTED pointer cast */
			sin = (struct sockaddr_in *)args->arg.nd_nbuf->buf;

			if ((args->arg.nd_nbuf->len !=
			    sizeof (struct sockaddr_in)) ||
			    (sin->sin_family != AF_INET)) {
				_nderror = ND_BADARG;
				return (_nderror);
			}
		}
		break;

		case NETDIR_BY6:
		case NETDIR_BY_NOSRV6:
		{
			struct sockaddr_in6 *sin6;

			if (args->arg.nd_nbuf == NULL) {
				_nderror = ND_BADARG;
				return (_nderror);
			}

			/*
			 * Validate the address which was passed
			 * as the request.
			 */
			/* LINTED pointer cast */
			sin6 = (struct sockaddr_in6 *)args->arg.nd_nbuf->buf;

			if ((args->arg.nd_nbuf->len !=
			    sizeof (struct sockaddr_in6)) ||
			    (sin6->sin6_family != AF_INET6)) {
				_nderror = ND_BADARG;
				return (_nderror);
			}
		}
		break;

	}

	/*
	 * 2. Most common scenario. This is the way we ship /etc/netconfig.
	 *    Emphasis on improving performance in the "if" part.
	 */
	if (nconf->nc_nlookups == 0) {
		struct hostent	*he = NULL, *tmphe;
		struct servent	*se = NULL;
		nss_XbyY_buf_t	*ndbuf4host = 0;
		nss_XbyY_buf_t	*ndbuf4serv = 0;
		char	*proto =
		    (strcmp(nconf->nc_proto, NC_TCP) == 0) ? NC_TCP : NC_UDP;
		struct	sockaddr_in *sa;
		struct sockaddr_in6 *sin6;
		struct in_addr *addr4 = 0;
		struct in6_addr v4mapbuf;
		int	h_errnop;

	switch (args->op_t) {

		case NSS_HOST:

		he = DOOR_GETHOSTBYADDR_R(args->arg.nss.host.addr,
		    args->arg.nss.host.len, args->arg.nss.host.type,
		    res->nss.host.hent, args->arg.nss.host.buf,
		    args->arg.nss.host.buflen,
		    res->nss.host.herrno_p);
		if (he == 0)
			_nderror = ND_NOHOST;
		else
			_nderror = ND_OK;
		return (_nderror);


		case NSS_HOST6:
		he = DOOR_GETIPNODEBYADDR_R(args->arg.nss.host.addr,
		    args->arg.nss.host.len, args->arg.nss.host.type,
		    res->nss.host.hent, args->arg.nss.host.buf,
		    args->arg.nss.host.buflen,
		    res->nss.host.herrno_p);

		if (he == 0)
			return (ND_NOHOST);
		return (ND_OK);


		case NSS_SERV:

		se = _switch_getservbyport_r(args->arg.nss.serv.port,
		    args->arg.nss.serv.proto,
		    res->nss.serv, args->arg.nss.serv.buf,
		    args->arg.nss.serv.buflen);

		if (se == 0)
			_nderror = ND_NOSERV;
		else
			_nderror = ND_OK;
		return (_nderror);

		case NETDIR_BY:
		case NETDIR_BY_NOSRV:

		ndbuf4serv = _nss_XbyY_buf_alloc(sizeof (struct servent),
		    NSS_BUFLEN_SERVICES);
		if (ndbuf4serv == 0) {
			_nderror = ND_NOMEM;
			return (_nderror);
		}
		/* LINTED pointer cast */
		sa = (struct sockaddr_in *)(args->arg.nd_nbuf->buf);
		addr4 = (struct in_addr *)&(sa->sin_addr);

		/*
		 * if NETDIR_BY_NOSRV or port == 0 skip the service
		 * lookup.
		 */
		if (args->op_t != NETDIR_BY_NOSRV && sa->sin_port != 0) {
			se = _switch_getservbyport_r(sa->sin_port, proto,
			    ndbuf4serv->result, ndbuf4serv->buffer,
			    ndbuf4serv->buflen);
			if (!se) {
				NSS_XbyY_FREE(&ndbuf4serv);
				/*
				 * We can live with this - i.e. the address
				 * does not
				 * belong to a well known service. The caller
				 * traditionally accepts a stringified port
				 * number
				 * as the service name. The state of se is used
				 * ahead to indicate the same.
				 * However, we do not tolerate this nonsense
				 * when we cannot get a host name. See below.
				 */
			}
		}

		ndbuf4host = _nss_XbyY_buf_alloc(sizeof (struct hostent),
		    NSS_BUFLEN_HOSTS);
		if (ndbuf4host == 0) {
			if (ndbuf4serv)
				NSS_XbyY_FREE(&ndbuf4serv);
			_nderror = ND_NOMEM;
			return (_nderror);
		}

		/*
		 * Since we're going to search the ipnodes (v6) path first,
		 * we need to treat the address as a v4mapped address.
		 */

		IN6_INADDR_TO_V4MAPPED(addr4, &v4mapbuf);
		if ((tmphe = DOOR_GETIPNODEBYADDR_R((char *)&v4mapbuf,
		    16, AF_INET6, ndbuf4host->result,
		    ndbuf4host->buffer,
		    ndbuf4host->buflen, &h_errnop)) != NULL)
			he = __mappedtov4(tmphe, &h_errnop);

		if (!he) {
			/* Failover case, try hosts db for v4 address */
			he = DOOR_GETHOSTBYADDR_R((char *)
			    &(sa->sin_addr.s_addr), 4,
			    sa->sin_family, ndbuf4host->result,
			    ndbuf4host->buffer, ndbuf4host->buflen,
			    &h_errnop);
			if (!he) {
				NSS_XbyY_FREE(&ndbuf4host);
				if (ndbuf4serv)
					NSS_XbyY_FREE(&ndbuf4serv);
				_nderror = __herrno2netdir(h_errnop);
				return (_nderror);
			}
			/*
			 * Convert host names and service names into hostserv