libsmbns/common/smbns_ads.c

	smbns_ads.c revision fe1c642d06e14b412cd83ae2179303186ab08972
/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/param.h>
#include <ldap.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <netdb.h>
#include <pthread.h>
#include <unistd.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <sys/synch.h>
#include <string.h>
#include <strings.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <sasl/sasl.h>
#include <note.h>

#include <smbsrv/libsmbns.h>
#include <smbns_dyndns.h>
#include <smbns_krb.h>

#define SMB_ADS_MAXBUFLEN 100
#define SMB_ADS_DN_MAX  300
#define SMB_ADS_MAXMSGLEN 512
#define SMB_ADS_COMPUTERS_CN "Computers"
#define SMB_ADS_COMPUTER_NUM_ATTR 8
#define SMB_ADS_SHARE_NUM_ATTR 3
#define SMB_ADS_SITE_MAX MAXHOSTNAMELEN

#define SMB_ADS_MSDCS_SRV_DC_RR     "_ldap._tcp.dc._msdcs"
#define SMB_ADS_MSDCS_SRV_SITE_RR   "_ldap._tcp.%s._sites.dc._msdcs"

/*
 * domainControllerFunctionality
 *
 * This rootDSE attribute indicates the functional level of the DC.
 */
#define SMB_ADS_ATTR_DCLEVEL    "domainControllerFunctionality"
#define SMB_ADS_DCLEVEL_W2K 0
#define SMB_ADS_DCLEVEL_W2K3    2
#define SMB_ADS_DCLEVEL_W2K8    3
#define SMB_ADS_DCLEVEL_W2K8_R2 4

/*
 * msDs-supportedEncryptionTypes (Windows Server 2008 only)
 *
 * This attribute defines the encryption types supported by the system.
 * Encryption Types:
 *  - DES cbc mode with CRC-32
 *  - DES cbc mode with RSA-MD5
 *  - ArcFour with HMAC/md5
 *  - AES-128
 *  - AES-256
 */
#define SMB_ADS_ATTR_ENCTYPES   "msDs-supportedEncryptionTypes"
#define SMB_ADS_ENC_DES_CRC 1
#define SMB_ADS_ENC_DES_MD5 2
#define SMB_ADS_ENC_RC4     4
#define SMB_ADS_ENC_AES128  8
#define SMB_ADS_ENC_AES256  16

#define SMB_ADS_ATTR_SAMACCT    "sAMAccountName"
#define SMB_ADS_ATTR_UPN    "userPrincipalName"
#define SMB_ADS_ATTR_SPN    "servicePrincipalName"
#define SMB_ADS_ATTR_CTL    "userAccountControl"
#define SMB_ADS_ATTR_DNSHOST    "dNSHostName"
#define SMB_ADS_ATTR_KVNO   "msDS-KeyVersionNumber"
#define SMB_ADS_ATTR_DN     "distinguishedName"

/*
 * UserAccountControl flags: manipulate user account properties.
 *
 * The hexadecimal value of the following property flags are based on MSDN
 * article # 305144.
 */
#define SMB_ADS_USER_ACCT_CTL_SCRIPT                0x00000001
#define SMB_ADS_USER_ACCT_CTL_ACCOUNTDISABLE            0x00000002
#define SMB_ADS_USER_ACCT_CTL_HOMEDIR_REQUIRED          0x00000008
#define SMB_ADS_USER_ACCT_CTL_LOCKOUT               0x00000010
#define SMB_ADS_USER_ACCT_CTL_PASSWD_NOTREQD            0x00000020
#define SMB_ADS_USER_ACCT_CTL_PASSWD_CANT_CHANGE        0x00000040
#define SMB_ADS_USER_ACCT_CTL_ENCRYPTED_TEXT_PWD_ALLOWED    0x00000080
#define SMB_ADS_USER_ACCT_CTL_TMP_DUP_ACCT          0x00000100
#define SMB_ADS_USER_ACCT_CTL_NORMAL_ACCT           0x00000200
#define SMB_ADS_USER_ACCT_CTL_INTERDOMAIN_TRUST_ACCT        0x00000800
#define SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT      0x00001000
#define SMB_ADS_USER_ACCT_CTL_SRV_TRUST_ACCT            0x00002000
#define SMB_ADS_USER_ACCT_CTL_DONT_EXPIRE_PASSWD        0x00010000
#define SMB_ADS_USER_ACCT_CTL_MNS_LOGON_ACCT            0x00020000
#define SMB_ADS_USER_ACCT_CTL_SMARTCARD_REQUIRED        0x00040000
#define SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION        0x00080000
#define SMB_ADS_USER_ACCT_CTL_NOT_DELEGATED         0x00100000
#define SMB_ADS_USER_ACCT_CTL_USE_DES_KEY_ONLY          0x00200000
#define SMB_ADS_USER_ACCT_CTL_DONT_REQ_PREAUTH          0x00400000
#define SMB_ADS_USER_ACCT_CTL_PASSWD_EXPIRED            0x00800000
#define SMB_ADS_USER_ACCT_CTL_TRUSTED_TO_AUTH_FOR_DELEGATION    0x01000000

/*
 * Length of "dc=" prefix.
 */
#define SMB_ADS_DN_PREFIX_LEN   3

static char *smb_ads_computer_objcls[] = {
    "top", "person", "organizationalPerson",
    "user", "computer", NULL
};

static char *smb_ads_share_objcls[] = {
    "top", "leaf", "connectionPoint", "volume", NULL
};

/* Cached ADS server to communicate with */
static smb_ads_host_info_t *smb_ads_cached_host_info = NULL;
static mutex_t smb_ads_cached_host_mtx;

/*
 * SMB ADS config cache is maintained to facilitate the detection of
 * changes in configuration that is relevant to AD selection.
 */
typedef struct smb_ads_config {
    char c_site[SMB_ADS_SITE_MAX];
    smb_inaddr_t c_pdc;
    mutex_t c_mtx;
} smb_ads_config_t;

static smb_ads_config_t smb_ads_cfg;


/* attribute/value pair */
typedef struct smb_ads_avpair {
    char *avp_attr;
    char *avp_val;
} smb_ads_avpair_t;

/* query status */
typedef enum smb_ads_qstat {
    SMB_ADS_STAT_ERR = -2,
    SMB_ADS_STAT_DUP,
    SMB_ADS_STAT_NOT_FOUND,
    SMB_ADS_STAT_FOUND
} smb_ads_qstat_t;

typedef struct smb_ads_host_list {
    int ah_cnt;
    smb_ads_host_info_t *ah_list;
} smb_ads_host_list_t;

static smb_ads_handle_t *smb_ads_open_main(char *, char *, char *);
static int smb_ads_add_computer(smb_ads_handle_t *, int, char *);
static int smb_ads_modify_computer(smb_ads_handle_t *, int, char *);
static int smb_ads_computer_op(smb_ads_handle_t *, int, int, char *);
static smb_ads_qstat_t smb_ads_lookup_computer_n_attr(smb_ads_handle_t *,
    smb_ads_avpair_t *, int, char *);
static int smb_ads_update_computer_cntrl_attr(smb_ads_handle_t *, int, char *);
static krb5_kvno smb_ads_lookup_computer_attr_kvno(smb_ads_handle_t *, char *);
static void smb_ads_gen_machine_passwd(char *, int);
static void smb_ads_free_cached_host(void);
static int smb_ads_get_spnset(char *, char **);
static void smb_ads_free_spnset(char **);
static int smb_ads_alloc_attr(LDAPMod **, int);
static void smb_ads_free_attr(LDAPMod **);
static int smb_ads_get_dc_level(smb_ads_handle_t *);
static smb_ads_host_info_t *smb_ads_select_dc(smb_ads_host_list_t *);
static smb_ads_qstat_t smb_ads_find_computer(smb_ads_handle_t *, char *);
static smb_ads_qstat_t smb_ads_getattr(LDAP *, LDAPMessage *,
    smb_ads_avpair_t *);
static smb_ads_qstat_t smb_ads_get_qstat(smb_ads_handle_t *, LDAPMessage *,
    smb_ads_avpair_t *);
static boolean_t smb_ads_match_pdc(smb_ads_host_info_t *);
static boolean_t smb_ads_is_sought_host(smb_ads_host_info_t *, char *);
static boolean_t smb_ads_is_same_domain(char *, char *);
static boolean_t smb_ads_is_pdc_configured(void);
static smb_ads_host_info_t *smb_ads_dup_host_info(smb_ads_host_info_t *);
static char *smb_ads_get_sharedn(const char *, const char *, const char *);

/*
 * smb_ads_init
 *
 * Initializes the ADS config cache.
 */
void
smb_ads_init(void)
{
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    (void) smb_config_getstr(SMB_CI_ADS_SITE,
        smb_ads_cfg.c_site, SMB_ADS_SITE_MAX);
    (void) smb_config_getip(SMB_CI_DOMAIN_SRV, &smb_ads_cfg.c_pdc);
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);
}

void
smb_ads_fini(void)
{
    smb_ads_free_cached_host();
}

/*
 * smb_ads_refresh
 *
 * This function will be called when smb/server SMF service is refreshed.
 * Clearing the smb_ads_cached_host_info would allow the next DC
 * discovery process to pick up an AD based on the new AD configuration.
 */
void
smb_ads_refresh(void)
{
    char new_site[SMB_ADS_SITE_MAX];
    smb_inaddr_t new_pdc;
    boolean_t purge = B_FALSE;

    (void) smb_config_getstr(SMB_CI_ADS_SITE, new_site, SMB_ADS_SITE_MAX);
    (void) smb_config_getip(SMB_CI_DOMAIN_SRV, &new_pdc);
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    if (smb_strcasecmp(smb_ads_cfg.c_site, new_site, 0)) {
        (void) strlcpy(smb_ads_cfg.c_site, new_site, SMB_ADS_SITE_MAX);
        purge = B_TRUE;
    }

    smb_ads_cfg.c_pdc = new_pdc;
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    (void) mutex_lock(&smb_ads_cached_host_mtx);
    if (smb_ads_cached_host_info &&
        smb_ads_is_pdc_configured() &&
        !smb_ads_match_pdc(smb_ads_cached_host_info))
        purge = B_TRUE;
    (void) mutex_unlock(&smb_ads_cached_host_mtx);

    if (purge)
        smb_ads_free_cached_host();
}


static boolean_t
smb_ads_is_pdc_configured(void)
{
    boolean_t configured;

    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    configured = !smb_inet_iszero(&smb_ads_cfg.c_pdc);
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    return (configured);
}

/*
 * smb_ads_build_unc_name
 *
 * Construct the UNC name of the share object in the format of
 * \\hostname.domain\shareUNC
 *
 * Returns 0 on success, -1 on error.
 */
int
smb_ads_build_unc_name(char *unc_name, int maxlen,
    const char *hostname, const char *shareUNC)
{
    char my_domain[MAXHOSTNAMELEN];

    if (smb_getfqdomainname(my_domain, sizeof (my_domain)) != 0)
        return (-1);

    (void) snprintf(unc_name, maxlen, "\\\\%s.%s\\%s",
        hostname, my_domain, shareUNC);
    return (0);
}

/*
 * smb_ads_ldap_ping
 *
 * This is used to bind to an ADS server to see
 * if it is still alive.
 *
 * Returns:
 *   -1: error
 *    0: successful
 */
/*ARGSUSED*/
static int
smb_ads_ldap_ping(smb_ads_host_info_t *ads_host)
{
    int ldversion = LDAP_VERSION3, status, timeoutms = 5 * 1000;
    LDAP *ld = NULL;

    ld = ldap_init(ads_host->name, ads_host->port);
    if (ld == NULL)
        return (-1);

    ldversion = LDAP_VERSION3;
    (void) ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, &ldversion);
    /* setup TCP/IP connect timeout */
    (void) ldap_set_option(ld, LDAP_X_OPT_CONNECT_TIMEOUT, &timeoutms);

    status = ldap_bind_s(ld, "", NULL, LDAP_AUTH_SIMPLE);

    if (status != LDAP_SUCCESS) {
        (void) ldap_unbind(ld);
        return (-1);
    }

    (void) ldap_unbind(ld);

    return (0);
}

/*
 * The cached ADS host is no longer valid if one of the following criteria
 * is satisfied:
 *
 * 1) not in the specified domain
 * 2) not the sought host (if specified)
 * 3) not reachable
 *
 * The caller is responsible for acquiring the smb_ads_cached_host_mtx lock
 * prior to calling this function.
 *
 * Return B_TRUE if the cache host is still valid. Otherwise, return B_FALSE.
 */
static boolean_t
smb_ads_validate_cache_host(char *domain, char *srv)
{
    if (!smb_ads_cached_host_info)
        return (B_FALSE);

    if (!smb_ads_is_same_domain(smb_ads_cached_host_info->name, domain))
        return (B_FALSE);

    if (smb_ads_ldap_ping(smb_ads_cached_host_info) == 0) {
        if (!srv)
            return (B_TRUE);

        if (smb_ads_is_sought_host(smb_ads_cached_host_info, srv))
            return (B_TRUE);
    }

    return (B_FALSE);
}

/*
 * smb_ads_is_sought_host
 *
 * Returns true, if the sought host name matches the input host (host) name.
 * The sought host is expected to be in Fully Qualified Domain Name (FQDN)
 * format.
 */
static boolean_t
smb_ads_is_sought_host(smb_ads_host_info_t *host, char *sought_host_name)
{
    if ((host == NULL) || (sought_host_name == NULL))
        return (B_FALSE);

    if (smb_strcasecmp(host->name, sought_host_name, 0))
        return (B_FALSE);

    return (B_TRUE);
}

/*
 * smb_ads_match_hosts_same_domain
 *
 * Returns true, if the cached ADS host is in the same domain as the
 * current (given) domain.
 */
static boolean_t
smb_ads_is_same_domain(char *cached_host_name, char *current_domain)
{
    char *cached_host_domain;

    if ((cached_host_name == NULL) || (current_domain == NULL))
        return (B_FALSE);

    cached_host_domain = strchr(cached_host_name, '.');
    if (cached_host_domain == NULL)
        return (B_FALSE);

    ++cached_host_domain;
    if (smb_strcasecmp(cached_host_domain, current_domain, 0))
        return (B_FALSE);

    return (B_TRUE);
}

/*
 * smb_ads_skip_ques_sec
 * Skips the question section.
 */
static int
smb_ads_skip_ques_sec(int qcnt, uchar_t **ptr, uchar_t *eom)
{
    int i, len;

    for (i = 0; i < qcnt; i++) {
        if ((len = dn_skipname(*ptr, eom)) < 0)
            return (-1);

        *ptr += len + QFIXEDSZ;
    }

    return (0);
}

/*
 * smb_ads_decode_host_ans_sec
 * Decodes ADS hosts, priority, weight and port number from the answer
 * section based on the current buffer pointer.
 */
static int
smb_ads_decode_host_ans_sec(int ans_cnt, uchar_t **ptr, uchar_t *eom,
    uchar_t *buf, smb_ads_host_info_t *ads_host_list)
{
    int i, len;
    smb_ads_host_info_t *ads_host;

    for (i = 0; i < ans_cnt; i++) {
        ads_host = &ads_host_list[i];

        if ((len = dn_skipname(*ptr, eom)) < 0)
            return (-1);


        *ptr += len;

        /* skip type, class, ttl */
        *ptr += 8;
        /* data size */
        *ptr += 2;

        /* Get priority, weight */
        /* LINTED: E_CONSTANT_CONDITION */
        NS_GET16(ads_host->priority, *ptr);
        /* LINTED: E_CONSTANT_CONDITION */
        NS_GET16(ads_host->weight, *ptr);

        /* port */
        /* LINTED: E_CONSTANT_CONDITION */
        NS_GET16(ads_host->port, *ptr);
        /* domain name */
        len = dn_expand(buf, eom, *ptr, ads_host->name, MAXHOSTNAMELEN);
        if (len < 0)
            return (-1);

        *ptr += len;
    }

    return (0);
}

/*
 * smb_ads_skip_auth_sec
 * Skips the authority section.
 */
static int
smb_ads_skip_auth_sec(int ns_cnt, uchar_t **ptr, uchar_t *eom)
{
    int i, len;
    uint16_t size;

    for (i = 0; i < ns_cnt; i++) {
        if ((len = dn_skipname(*ptr, eom)) < 0)
            return (-1);

        *ptr += len;
        /* skip type, class, ttl */
        *ptr += 8;
        /* get len of data */
        /* LINTED: E_CONSTANT_CONDITION */
        NS_GET16(size, *ptr);
        if ((*ptr + size) > eom)
            return (-1);

        *ptr += size;
    }

    return (0);
}

/*
 * smb_ads_decode_host_ip
 *
 * Decodes ADS hosts and IP Addresses from the additional section based
 * on the current buffer pointer.
 */
static int
smb_ads_decode_host_ip(int addit_cnt, int ans_cnt, uchar_t **ptr,
    uchar_t *eom, uchar_t *buf, smb_ads_host_info_t *ads_host_list)
{
    int i, j, len;
    smb_inaddr_t ipaddr;
    char hostname[MAXHOSTNAMELEN];
    char *name;
    uint16_t size = 0;

    for (i = 0; i < addit_cnt; i++) {

        /* domain name */
        len = dn_expand(buf, eom, *ptr, hostname, MAXHOSTNAMELEN);
        if (len < 0)
            return (-1);

        *ptr += len;

        /* skip type, class, TTL, data len */
        *ptr += 8;
        /* LINTED: E_CONSTANT_CONDITION */
        NS_GET16(size, *ptr);

        if (size == INADDRSZ) {
            /* LINTED: E_CONSTANT_CONDITION */
            NS_GET32(ipaddr.a_ipv4, *ptr);
            ipaddr.a_ipv4 = htonl(ipaddr.a_ipv4);
            ipaddr.a_family = AF_INET;
        } else if (size == IN6ADDRSZ) {
#ifdef BIG_ENDIAN
            bcopy(*ptr, &ipaddr.a_ipv6, IN6ADDRSZ);
#else
            for (i = 0; i < IN6ADDRSZ; i++)
                (uint8_t *)(ipaddr.a_ipv6)
                    [IN6ADDRSZ-1-i] = *(*ptr+i);
#endif
            ipaddr.a_family = AF_INET6;
        }

        /*
         * find the host in the list of DC records from
         * the answer section, that matches the host in the
         * additional section, and set its IP address.
         */
        for (j = 0; j < ans_cnt; j++) {
            if ((name = ads_host_list[j].name) == NULL)
                continue;
            if (smb_strcasecmp(name, hostname, 0) == 0) {
                ads_host_list[j].ipaddr = ipaddr;
            }
        }
    }
    return (0);
}

/*
 * smb_ads_dup_host_info
 *
 * Duplicates the passed smb_ads_host_info_t structure.
 * Caller must free memory allocated by this method.
 *
 * Returns a reference to the duplicated smb_ads_host_info_t structure.
 * Returns NULL on error.
 */
static smb_ads_host_info_t *
smb_ads_dup_host_info(smb_ads_host_info_t *ads_host)
{
    smb_ads_host_info_t *dup_host;

    if (ads_host == NULL)
        return (NULL);

    dup_host = malloc(sizeof (smb_ads_host_info_t));

    if (dup_host != NULL)
        bcopy(ads_host, dup_host, sizeof (smb_ads_host_info_t));

    return (dup_host);
}

/*
 * smb_ads_hlist_alloc
 */
static smb_ads_host_list_t *
smb_ads_hlist_alloc(int count)
{
    int size;
    smb_ads_host_list_t *hlist;

    if (count == 0)
        return (NULL);

    size = sizeof (smb_ads_host_info_t) * count;
    hlist = (smb_ads_host_list_t *)malloc(sizeof (smb_ads_host_list_t));
    if (hlist == NULL)
        return (NULL);

    hlist->ah_cnt = count;
    hlist->ah_list = (smb_ads_host_info_t *)malloc(size);
    if (hlist->ah_list == NULL) {
        free(hlist);
        return (NULL);
    }

    bzero(hlist->ah_list, size);
    return (hlist);
}

/*
 * smb_ads_hlist_free
 */
static void
smb_ads_hlist_free(smb_ads_host_list_t *host_list)
{
    if (host_list == NULL)
        return;

    free(host_list->ah_list);
    free(host_list);
}

/*
 * smb_ads_query_dns_server
 *
 * This routine sends a DNS service location (SRV) query message to the
 * DNS server via TCP to query it for a list of ADS server(s). Once a reply
 * is received, the reply message is parsed to get the hostname. If there are IP
 * addresses populated in the additional section then the additional section
 * is parsed to obtain the IP addresses.
 *
 * The service location of _ldap._tcp.dc.msdcs.<ADS domain> is used to
 * guarantee that Microsoft domain controllers are returned.  Microsoft domain
 * controllers are also ADS servers.
 *
 * The ADS hostnames are stored in the answer section of the DNS reply message.
 * The IP addresses are stored in the additional section.
 *
 * The DNS reply message may be in compress formed.  The compression is done
 * on repeating domain name label in the message.  i.e hostname.
 *
 * Upon successful completion, host list of ADS server(s) is returned.
 */
static smb_ads_host_list_t *
smb_ads_query_dns_server(char *domain, char *msdcs_svc_name)
{
    smb_ads_host_list_t *hlist = NULL;
    int len, qcnt, ans_cnt, ns_cnt, addit_cnt;
    uchar_t *ptr, *eom;
    struct __res_state res_state;
    union {
        HEADER hdr;
        uchar_t buf[NS_MAXMSG];
    } msg;

    bzero(&res_state, sizeof (struct __res_state));
    if (res_ninit(&res_state) < 0)
        return (NULL);

    /* use TCP */
    res_state.options |= RES_USEVC;

    len = res_nquerydomain(&res_state, msdcs_svc_name, domain,
        C_IN, T_SRV, msg.buf, sizeof (msg.buf));

    if (len < 0) {
        syslog(LOG_NOTICE, "DNS query for %s failed: %s",
            msdcs_svc_name, hstrerror(res_state.res_h_errno));
        res_ndestroy(&res_state);
        return (NULL);
    }

    if (len > sizeof (msg.buf)) {
        syslog(LOG_NOTICE,
            "DNS query for %s failed: too big", msdcs_svc_name);
        res_ndestroy(&res_state);
        return (NULL);
    }

    /* parse the reply, skip header and question sections */
    ptr = msg.buf + sizeof (msg.hdr);
    eom = msg.buf + len;

    /* check truncated message bit */
    if (msg.hdr.tc)
        syslog(LOG_NOTICE,
            "DNS query for %s failed: truncated", msdcs_svc_name);

    qcnt = ntohs(msg.hdr.qdcount);
    ans_cnt = ntohs(msg.hdr.ancount);
    ns_cnt = ntohs(msg.hdr.nscount);
    addit_cnt = ntohs(msg.hdr.arcount);

    if (smb_ads_skip_ques_sec(qcnt, &ptr, eom) != 0) {
        res_ndestroy(&res_state);
        return (NULL);
    }

    hlist = smb_ads_hlist_alloc(ans_cnt);
    if (hlist == NULL) {
        res_ndestroy(&res_state);
        return (NULL);
    }

    /* walk through the answer section */
    if (smb_ads_decode_host_ans_sec(ans_cnt, &ptr, eom, msg.buf,
        hlist->ah_list) != 0) {
        smb_ads_hlist_free(hlist);
        res_ndestroy(&res_state);
        return (NULL);
    }

    /* check authority section */
    if (ns_cnt > 0) {
        if (smb_ads_skip_auth_sec(ns_cnt, &ptr, eom) != 0) {
            smb_ads_hlist_free(hlist);
            res_ndestroy(&res_state);
            return (NULL);
        }
    }

    /*
     * Check additional section to get IP address of ADS host.
     */
    if (addit_cnt > 0) {
        if (smb_ads_decode_host_ip(addit_cnt, ans_cnt,
            &ptr, eom, msg.buf, hlist->ah_list) != 0) {
            smb_ads_hlist_free(hlist);
            res_ndestroy(&res_state);
            return (NULL);
        }
    }

    res_ndestroy(&res_state);
    return (hlist);
}

/*
 * smb_ads_get_site_service
 *
 * Gets the msdcs SRV RR for the specified site.
 */
static void
smb_ads_get_site_service(char *site_service, size_t len)
{
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    if (*smb_ads_cfg.c_site == '\0')
        *site_service = '\0';
    else
        (void) snprintf(site_service, len,
            SMB_ADS_MSDCS_SRV_SITE_RR, smb_ads_cfg.c_site);

    (void) mutex_unlock(&smb_ads_cfg.c_mtx);
}

/*
 * smb_ads_getipnodebyname
 *
 * This method gets the IP address by doing a host name lookup.
 */
static int
smb_ads_getipnodebyname(smb_ads_host_info_t *hentry)
{
    struct hostent *h;
    int error;

    switch (hentry->ipaddr.a_family) {
    case AF_INET6:
        h = getipnodebyname(hentry->name, hentry->ipaddr.a_family,
            AI_DEFAULT, &error);
        if (h == NULL || h->h_length != IPV6_ADDR_LEN)
            return (-1);
        break;

    case AF_INET:
        h = getipnodebyname(hentry->name, hentry->ipaddr.a_family,
            0, &error);
        if (h == NULL || h->h_length != INADDRSZ)
            return (-1);
        break;

    default:
        return (-1);
    }
    bcopy(*(h->h_addr_list), &hentry->ipaddr.a_ip, h->h_length);
    freehostent(h);
    return (0);
}

/*
 * smb_ads_find_host
 *
 * Finds an ADS host in a given domain.
 *
 * If the cached host is valid, it will be used. Otherwise, a DC will
 * be selected based on the following criteria:
 *
 * 1) pdc (aka preferred DC) configuration
 * 2) AD site configuration - the scope of the DNS lookup will be
 * restricted to the specified site.
 * 3) DC on the same subnet
 * 4) DC with the lowest priority/highest weight
 *
 * The above items are listed in decreasing preference order. The selected
 * DC must be online.
 *
 * If this function is called during domain join, the specified kpasswd server
 * takes precedence over preferred DC, AD site, and so on.
 *
 * Parameters:
 *   domain: fully-qualified domain name.
 *   kpasswd_srv: fully-quailifed hostname of the kpasswd server.
 *
 * Returns:
 *   A copy of the cached host info is returned. The caller is responsible
 *   for deallocating the memory returned by this function.
 */
/*ARGSUSED*/
smb_ads_host_info_t *
smb_ads_find_host(char *domain, char *kpasswd_srv)
{
    int i;
    char site_service[MAXHOSTNAMELEN];
    smb_ads_host_list_t *hlist, *hlist2;
    smb_ads_host_info_t *hlistp = NULL, *host = NULL;
    smb_ads_host_info_t *found_kpasswd_srv = NULL;
    smb_ads_host_info_t *found_pdc = NULL;

    if ((kpasswd_srv) && (*kpasswd_srv == '\0'))
        kpasswd_srv = NULL;

    (void) mutex_lock(&smb_ads_cached_host_mtx);
    if (smb_ads_validate_cache_host(domain, kpasswd_srv)) {
        host = smb_ads_dup_host_info(smb_ads_cached_host_info);
        (void) mutex_unlock(&smb_ads_cached_host_mtx);
        return (host);
    }

    (void) mutex_unlock(&smb_ads_cached_host_mtx);
    smb_ads_free_cached_host();

    /*
     * First look for ADS hosts in ADS site if configured.  Then try
     * without ADS site info.
     */
    hlist = NULL;
    smb_ads_get_site_service(site_service, MAXHOSTNAMELEN);

    /*
     * If we're given an AD, the DNS SRV RR lookup should not be restricted
     * to the specified site since there is no guarantee that the specified
     * AD is in the specified site.
     */
    if (*site_service != '\0' && !kpasswd_srv &&
        !smb_ads_is_pdc_configured())
        hlist = smb_ads_query_dns_server(domain, site_service);

    if (!hlist)
        hlist = smb_ads_query_dns_server(domain,
            SMB_ADS_MSDCS_SRV_DC_RR);

    if ((hlist == NULL) || (hlist->ah_list == NULL) || (hlist->ah_cnt == 0))
        return (NULL);

    for (i = 0, hlistp = hlist->ah_list; i < hlist->ah_cnt; i++) {
        /* Do a host lookup by hostname to get the IP address */
        if (smb_inet_iszero(&hlistp[i].ipaddr)) {
            if (smb_ads_getipnodebyname(&hlistp[i]) < 0)
                continue;
        }

        if (smb_ads_is_sought_host(&hlistp[i], kpasswd_srv))
            found_kpasswd_srv = &hlistp[i];

        if (smb_ads_match_pdc(&hlistp[i]))
            found_pdc = &hlistp[i];
    }

    if (found_kpasswd_srv && smb_ads_ldap_ping(found_kpasswd_srv) == 0) {
        host = found_kpasswd_srv;
        goto update_cache;
    }

    if (found_pdc && smb_ads_ldap_ping(found_pdc) == 0) {
        host = found_pdc;
        goto update_cache;
    }

    /*
     * If the specified DC (kpasswd_srv or pdc) is not found, fallback
     * to find a DC in the specified AD site.
     */
    if (*site_service != '\0' &&
        (kpasswd_srv || smb_ads_is_pdc_configured())) {
        hlist2 = smb_ads_query_dns_server(domain, site_service);
        if (hlist2 && hlist2->ah_list && hlist2->ah_cnt != 0) {
            smb_ads_hlist_free(hlist);
            hlist = hlist2;
            hlistp = hlist->ah_list;

            for (i = 0; i < hlist->ah_cnt; i++) {
                if (smb_inet_iszero(&hlistp[i].ipaddr) &&
                    smb_ads_getipnodebyname(&hlistp[i]) < 0)
                        continue;
            }
        }
    }

    /* Select DC from DC list */
    host = smb_ads_select_dc(hlist);

update_cache:
    if (host) {
        (void) mutex_lock(&smb_ads_cached_host_mtx);
        if (!smb_ads_cached_host_info)
            smb_ads_cached_host_info = smb_ads_dup_host_info(host);
        host = smb_ads_dup_host_info(smb_ads_cached_host_info);
        (void) mutex_unlock(&smb_ads_cached_host_mtx);
    }

    smb_ads_hlist_free(hlist);
    return (host);
}

/*
 * Return the number of dots in a string.
 */
static int
smb_ads_count_dots(const char *s)
{
    int ndots = 0;

    while (*s) {
        if (*s++ == '.')
            ndots++;
    }

    return (ndots);
}

/*
 * Convert a domain name in dot notation to distinguished name format,
 * for example: sun.com -> dc=sun,dc=com.
 *
 * Returns a pointer to an allocated buffer containing the distinguished
 * name.
 */
static char *
smb_ads_convert_domain(const char *domain_name)
{
    const char *s;
    char *dn_name;
    char buf[2];
    int ndots;
    int len;

    if (domain_name == NULL || *domain_name == 0)
        return (NULL);

    ndots = smb_ads_count_dots(domain_name);
    ++ndots;
    len = strlen(domain_name) + (ndots * SMB_ADS_DN_PREFIX_LEN) + 1;

    if ((dn_name = malloc(len)) == NULL)
        return (NULL);

    bzero(dn_name, len);
    (void) strlcpy(dn_name, "dc=", len);

    buf[1] = '\0';
    s = domain_name;

    while (*s) {
        if (*s == '.') {
            (void) strlcat(dn_name, ",dc=", len);
        } else {
            buf[0] = *s;
            (void) strlcat(dn_name, buf, len);
        }
        ++s;
    }

    return (dn_name);
}

/*
 * smb_ads_free_cached_host
 *
 * Free the memory use by the global smb_ads_cached_host_info & set it to NULL.
 */
static void
smb_ads_free_cached_host(void)
{
    (void) mutex_lock(&smb_ads_cached_host_mtx);
    if (smb_ads_cached_host_info) {
        free(smb_ads_cached_host_info);
        smb_ads_cached_host_info = NULL;
    }
    (void) mutex_unlock(&smb_ads_cached_host_mtx);
}

/*
 * smb_ads_open
 * Open a LDAP connection to an ADS server if the system is in domain mode.
 * Acquire both Kerberos TGT and LDAP service tickets for the host principal.
 *
 * This function should only be called after the system is successfully joined
 * to a domain.
 */
smb_ads_handle_t *
smb_ads_open(void)
{
    char domain[MAXHOSTNAMELEN];

    if (smb_config_get_secmode() != SMB_SECMODE_DOMAIN)
        return (NULL);

    if (smb_getfqdomainname(domain, MAXHOSTNAMELEN) != 0)
        return (NULL);

    return (smb_ads_open_main(domain, NULL, NULL));
}

static int
smb_ads_saslcallback(LDAP *ld, unsigned flags, void *defaults, void *prompts)
{
    NOTE(ARGUNUSED(ld, defaults));
    sasl_interact_t *interact;

    if (prompts == NULL || flags != LDAP_SASL_INTERACTIVE)
        return (LDAP_PARAM_ERROR);

    /* There should be no extra arguemnts for SASL/GSSAPI authentication */
    for (interact = prompts; interact->id != SASL_CB_LIST_END;
        interact++) {
        interact->result = NULL;
        interact->len = 0;
    }
    return (LDAP_SUCCESS);
}

/*
 * smb_ads_open_main
 * Open a LDAP connection to an ADS server.
 * If ADS is enabled and the administrative username, password, and
 * ADS domain are defined then query DNS to find an ADS server if this is the
 * very first call to this routine.  After an ADS server is found then this
 * server will be used everytime this routine is called until the system is
 * rebooted or the ADS server becomes unavailable then an ADS server will
 * be queried again.  After the connection is made then an ADS handle
 * is created to be returned.
 *
 * After the LDAP connection, the LDAP version will be set to 3 using
 * ldap_set_option().
 *
 * The LDAP connection is bound before the ADS handle is returned.
 * Parameters:
 *   domain - fully-qualified domain name
 *   user   - the user account for whom the Kerberos TGT ticket and ADS
 *            service tickets are acquired.
 *   password - password of the specified user
 *
 * Returns:
 *   NULL              : can't connect to ADS server or other errors
 *   smb_ads_handle_t* : handle to ADS server
 */
static smb_ads_handle_t *
smb_ads_open_main(char *domain, char *user, char *password)
{
    smb_ads_handle_t *ah;
    LDAP *ld;
    int version = 3;
    smb_ads_host_info_t *ads_host = NULL;
    int rc;

    if (user != NULL) {
        if (smb_kinit(user, password) == 0)
            return (NULL);
        user = NULL;
        password = NULL;
    }

    ads_host = smb_ads_find_host(domain, NULL);
    if (ads_host == NULL)
        return (NULL);

    ah = (smb_ads_handle_t *)malloc(sizeof (smb_ads_handle_t));
    if (ah == NULL) {
        free(ads_host);
        return (NULL);
    }

    (void) memset(ah, 0, sizeof (smb_ads_handle_t));

    if ((ld = ldap_init(ads_host->name, ads_host->port)) == NULL) {
        smb_ads_free_cached_host();
        free(ah);
        free(ads_host);
        return (NULL);
    }

    if (ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, &version)
        != LDAP_SUCCESS) {
        smb_ads_free_cached_host();
        free(ah);
        free(ads_host);
        (void) ldap_unbind(ld);
        return (NULL);
    }

    (void) ldap_set_option(ld, LDAP_OPT_REFERRALS, LDAP_OPT_OFF);
    ah->ld = ld;
    ah->domain = strdup(domain);

    if (ah->domain == NULL) {
        smb_ads_close(ah);
        free(ads_host);
        return (NULL);
    }

    ah->domain_dn = smb_ads_convert_domain(domain);
    if (ah->domain_dn == NULL) {
        smb_ads_close(ah);
        free(ads_host);
        return (NULL);
    }

    ah->hostname = strdup(ads_host->name);
    if (ah->hostname == NULL) {
        smb_ads_close(ah);
        free(ads_host);
        return (NULL);
    }
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    if (*smb_ads_cfg.c_site != '\0') {
        if ((ah->site = strdup(smb_ads_cfg.c_site)) == NULL) {
            smb_ads_close(ah);
            (void) mutex_unlock(&smb_ads_cfg.c_mtx);
            free(ads_host);
            return (NULL);
        }
    } else {
        ah->site = NULL;
    }
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    rc = ldap_sasl_interactive_bind_s(ah->ld, "", "GSSAPI", NULL, NULL,
        LDAP_SASL_INTERACTIVE, &smb_ads_saslcallback, NULL);
    if (rc != LDAP_SUCCESS) {
        syslog(LOG_ERR, "ldal_sasl_interactive_bind_s failed (%s)",
            ldap_err2string(rc));
        smb_ads_close(ah);
        free(ads_host);
        return (NULL);
    }

    free(ads_host);
    return (ah);
}

/*
 * smb_ads_close
 * Close connection to ADS server and free memory allocated for ADS handle.
 * LDAP unbind is called here.
 * Parameters:
 *   ah: handle to ADS server
 * Returns:
 *   void
 */
void
smb_ads_close(smb_ads_handle_t *ah)
{
    if (ah == NULL)
        return;
    /* close and free connection resources */
    if (ah->ld)
        (void) ldap_unbind(ah->ld);

    free(ah->domain);
    free(ah->domain_dn);
    free(ah->hostname);
    free(ah->site);
    free(ah);
}

/*
 * smb_ads_alloc_attr
 *
 * Since the attrs is a null-terminated array, all elements
 * in the array (except the last one) will point to allocated
 * memory.
 */
static int
smb_ads_alloc_attr(LDAPMod *attrs[], int num)
{
    int i;

    bzero(attrs, num * sizeof (LDAPMod *));
    for (i = 0; i < (num - 1); i++) {
        attrs[i] = (LDAPMod *)malloc(sizeof (LDAPMod));
        if (attrs[i] == NULL) {
            smb_ads_free_attr(attrs);
            return (-1);
        }
    }

    return (0);
}

/*
 * smb_ads_free_attr
 * Free memory allocated when publishing a share.
 * Parameters:
 *   attrs: an array of LDAPMod pointers
 * Returns:
 *   None
 */
static void
smb_ads_free_attr(LDAPMod *attrs[])
{
    int i;
    for (i = 0; attrs[i]; i++) {
        free(attrs[i]);
    }
}

/*
 * smb_ads_get_spnset
 *
 * Derives the core set of SPNs based on the FQHN.
 * The spn_set is a null-terminated array of char pointers.
 *
 * Returns 0 upon success. Otherwise, returns -1.
 */
static int
smb_ads_get_spnset(char *fqhost, char **spn_set)
{
    int i;

    bzero(spn_set, (SMBKRB5_SPN_IDX_MAX + 1) * sizeof (char *));
    for (i = 0; i < SMBKRB5_SPN_IDX_MAX; i++) {
        if ((spn_set[i] = smb_krb5_get_spn(i, fqhost)) == NULL) {
            smb_ads_free_spnset(spn_set);
            return (-1);
        }
    }

    return (0);
}

/*
 * smb_ads_free_spnset
 *
 * Free the memory allocated for the set of SPNs.
 */
static void
smb_ads_free_spnset(char **spn_set)
{
    int i;
    for (i = 0; spn_set[i]; i++)
        free(spn_set[i]);
}

/*
 * Returns share DN in an allocated buffer.  The format of the DN is
 * cn=<sharename>,<container RDNs>,<domain DN>
 *
 * If the domain DN is not included in the container parameter,
 * then it will be appended to create the share DN.
 *
 * The caller must free the allocated buffer.
 */
static char *
smb_ads_get_sharedn(const char *sharename, const char *container,
    const char *domain_dn)
{
    char *share_dn;
    int rc, offset, container_len, domain_len;
    boolean_t append_domain = B_TRUE;

    container_len = strlen(container);
    domain_len = strlen(domain_dn);

    if (container_len >= domain_len) {

        /* offset to last domain_len characters */
        offset = container_len - domain_len;

        if (smb_strcasecmp(container + offset,
            domain_dn, domain_len) == 0)
            append_domain = B_FALSE;
    }

    if (append_domain)
        rc = asprintf(&share_dn, "cn=%s,%s,%s", sharename,
            container, domain_dn);
    else
        rc = asprintf(&share_dn, "cn=%s,%s", sharename,
            container);

    return ((rc == -1) ? NULL : share_dn);
}

/*
 * smb_ads_add_share
 * Call by smb_ads_publish_share to create share object in ADS.
 * This routine specifies the attributes of an ADS LDAP share object. The first
 * attribute and values define the type of ADS object, the share object.  The
 * second attribute and value define the UNC of the share data for the share
 * object. The LDAP synchronous add command is used to add the object into ADS.
 * The container location to add the object needs to specified.
 * Parameters:
 *   ah          : handle to ADS server
 *   adsShareName: name of share object to be created in ADS
 *   shareUNC    : share name on NetForce
 *   adsContainer: location in ADS to create share object
 *
 * Returns:
 *   -1          : error
 *    0          : success
 */
int
smb_ads_add_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *unc_name, const char *adsContainer)
{
    LDAPMod *attrs[SMB_ADS_SHARE_NUM_ATTR];
    int j = 0;
    char *share_dn;
    int ret;
    char *unc_names[] = {(char *)unc_name, NULL};

    if ((share_dn = smb_ads_get_sharedn(adsShareName, adsContainer,
        ah->domain_dn)) == NULL)
        return (-1);

    if (smb_ads_alloc_attr(attrs, SMB_ADS_SHARE_NUM_ATTR) != 0) {
        free(share_dn);
        return (-1);
    }

    attrs[j]->mod_op = LDAP_MOD_ADD;
    attrs[j]->mod_type = "objectClass";
    attrs[j]->mod_values = smb_ads_share_objcls;

    attrs[++j]->mod_op = LDAP_MOD_ADD;
    attrs[j]->mod_type = "uNCName";
    attrs[j]->mod_values = unc_names;

    if ((ret = ldap_add_s(ah->ld, share_dn, attrs)) != LDAP_SUCCESS) {
        smb_tracef("%s: ldap_add: %s", share_dn, ldap_err2string(ret));
        smb_ads_free_attr(attrs);
        free(share_dn);
        return (ret);
    }
    free(share_dn);
    smb_ads_free_attr(attrs);

    return (0);
}

/*
 * smb_ads_del_share
 * Call by smb_ads_remove_share to remove share object from ADS.  The container
 * location to remove the object needs to specified.  The LDAP synchronous
 * delete command is used.
 * Parameters:
 *   ah          : handle to ADS server
 *   adsShareName: name of share object in ADS to be removed
 *   adsContainer: location of share object in ADS
 * Returns:
 *   -1          : error
 *    0          : success
 */
static int
smb_ads_del_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *adsContainer)
{
    char *share_dn;
    int ret;

    if ((share_dn = smb_ads_get_sharedn(adsShareName, adsContainer,
        ah->domain_dn)) == NULL)
        return (-1);

    if ((ret = ldap_delete_s(ah->ld, share_dn)) != LDAP_SUCCESS) {
        smb_tracef("ldap_delete: %s", ldap_err2string(ret));
        free(share_dn);
        return (-1);
    }
    free(share_dn);

    return (0);
}


/*
 * smb_ads_escape_search_filter_chars
 *
 * This routine will escape the special characters found in a string
 * that will later be passed to the ldap search filter.
 *
 * RFC 1960 - A String Representation of LDAP Search Filters
 * 3.  String Search Filter Definition
 * If a value must contain one of the characters '*' OR '(' OR ')',
 * these characters
 * should be escaped by preceding them with the backslash '\' character.
 *
 * RFC 2252 - LDAP Attribute Syntax Definitions
 * a backslash quoting mechanism is used to escape
 * the following separator symbol character (such as "'", "$" or "#") if
 * it should occur in that string.
 */
static int
smb_ads_escape_search_filter_chars(const char *src, char *dst)
{
    int avail = SMB_ADS_MAXBUFLEN - 1; /* reserve a space for NULL char */

    if (src == NULL || dst == NULL)
        return (-1);

    while (*src) {
        if (!avail) {
            *dst = 0;
            return (-1);
        }

        switch (*src) {
        case '\\':
        case '\'':
        case '$':
        case '#':
        case '*':
        case '(':
        case ')':
            *dst++ = '\\';
            avail--;
            /* fall through */

        default:
            *dst++ = *src++;
            avail--;
        }
    }

    *dst = 0;

    return (0);
}

/*
 * smb_ads_lookup_share
 * The search filter is set to search for a specific share name in the
 * specified ADS container.  The LDSAP synchronous search command is used.
 * Parameters:
 *   ah          : handle to ADS server
 *   adsShareName: name of share object in ADS to be searched
 *   adsContainer: location of share object in ADS
 * Returns:
 *   -1          : error
 *    0          : not found
 *    1          : found
 */
int
smb_ads_lookup_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *adsContainer, char *unc_name)
{
    char *attrs[4], filter[SMB_ADS_MAXBUFLEN];
    char *share_dn;
    int ret;
    LDAPMessage *res;
    char tmpbuf[SMB_ADS_MAXBUFLEN];

    if (adsShareName == NULL || adsContainer == NULL)
        return (-1);

    if ((share_dn = smb_ads_get_sharedn(adsShareName, adsContainer,
        ah->domain_dn)) == NULL)
        return (-1);

    res = NULL;
    attrs[0] = "cn";
    attrs[1] = "objectClass";
    attrs[2] = "uNCName";
    attrs[3] = NULL;

    if (smb_ads_escape_search_filter_chars(unc_name, tmpbuf) != 0) {
        free(share_dn);
        return (-1);
    }

    (void) snprintf(filter, sizeof (filter),
        "(&(objectClass=volume)(uNCName=%s))", tmpbuf);

    if ((ret = ldap_search_s(ah->ld, share_dn,
        LDAP_SCOPE_BASE, filter, attrs, 0, &res)) != LDAP_SUCCESS) {
        if (ret != LDAP_NO_SUCH_OBJECT)
            smb_tracef("%s: ldap_search: %s", share_dn,
                ldap_err2string(ret));

        (void) ldap_msgfree(res);
        free(share_dn);
        return (0);
    }

    (void) free(share_dn);

    /* no match is found */
    if (ldap_count_entries(ah->ld, res) == 0) {
        (void) ldap_msgfree(res);
        return (0);
    }

    /* free the search results */
    (void) ldap_msgfree(res);

    return (1);
}

/*
 * smb_ads_publish_share
 * Publish share into ADS.  If a share name already exist in ADS in the same
 * container then the existing share object is removed before adding the new
 * share object.
 * Parameters:
 *   ah          : handle return from smb_ads_open
 *   adsShareName: name of share to be added to ADS directory
 *   shareUNC    : name of share on client, can be NULL to use the same name
 *                 as adsShareName
 *   adsContainer: location for share to be added in ADS directory, ie
 *                   ou=share_folder
 *   uncType     : use UNC_HOSTNAME to use hostname for UNC, use UNC_HOSTADDR
 *                   to use host ip addr for UNC.
 * Returns:
 *   -1          : error
 *    0          : success
 */
int
smb_ads_publish_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *shareUNC, const char *adsContainer, const char *hostname)
{
    int ret;
    char unc_name[SMB_ADS_MAXBUFLEN];

    if (adsShareName == NULL || adsContainer == NULL)
        return (-1);

    if (shareUNC == 0 || *shareUNC == 0)
        shareUNC = adsShareName;

    if (smb_ads_build_unc_name(unc_name, sizeof (unc_name),
        hostname, shareUNC) < 0)
        return (-1);

    ret = smb_ads_lookup_share(ah, adsShareName, adsContainer, unc_name);

    switch (ret) {
    case 1:
        (void) smb_ads_del_share(ah, adsShareName, adsContainer);
        ret = smb_ads_add_share(ah, adsShareName, unc_name,
            adsContainer);
        break;

    case 0:
        ret = smb_ads_add_share(ah, adsShareName, unc_name,
            adsContainer);
        if (ret == LDAP_ALREADY_EXISTS)
            ret = -1;

        break;

    case -1:
    default:
        /* return with error code */
        ret = -1;
    }

    return (ret);
}

/*
 * smb_ads_remove_share
 * Remove share from ADS.  A search is done first before explicitly removing
 * the share.
 * Parameters:
 *   ah          : handle return from smb_ads_open
 *   adsShareName: name of share to be removed from ADS directory
 *   adsContainer: location for share to be removed from ADS directory, ie
 *                   ou=share_folder
 * Returns:
 *   -1          : error
 *    0          : success
 */
int
smb_ads_remove_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *shareUNC, const char *adsContainer, const char *hostname)
{
    int ret;
    char unc_name[SMB_ADS_MAXBUFLEN];

    if (adsShareName == NULL || adsContainer == NULL)
        return (-1);
    if (shareUNC == 0 || *shareUNC == 0)
        shareUNC = adsShareName;

    if (smb_ads_build_unc_name(unc_name, sizeof (unc_name),
        hostname, shareUNC) < 0)
        return (-1);

    ret = smb_ads_lookup_share(ah, adsShareName, adsContainer, unc_name);
    if (ret == 0)
        return (0);
    if (ret == -1)
        return (-1);

    return (smb_ads_del_share(ah, adsShareName, adsContainer));
}

/*
 * smb_ads_get_default_comp_container_dn
 *
 * Build the distinguished name for the default computer conatiner (i.e. the
 * pre-defined Computers container).
 */
static void
smb_ads_get_default_comp_container_dn(smb_ads_handle_t *ah, char *buf,
    size_t buflen)
{
    (void) snprintf(buf, buflen, "cn=%s,%s", SMB_ADS_COMPUTERS_CN,
        ah->domain_dn);
}

/*
 * smb_ads_get_default_comp_dn
 *
 * Build the distinguished name for this system.
 */
static void
smb_ads_get_default_comp_dn(smb_ads_handle_t *ah, char *buf, size_t buflen)
{
    char nbname[NETBIOS_NAME_SZ];
    char container_dn[SMB_ADS_DN_MAX];

    (void) smb_getnetbiosname(nbname, sizeof (nbname));
    smb_ads_get_default_comp_container_dn(ah, container_dn, SMB_ADS_DN_MAX);
    (void) snprintf(buf, buflen, "cn=%s,%s", nbname, container_dn);
}

/*
 * smb_ads_add_computer
 *
 * Returns 0 upon success. Otherwise, returns -1.
 */
static int
smb_ads_add_computer(smb_ads_handle_t *ah, int dclevel, char *dn)
{
    return (smb_ads_computer_op(ah, LDAP_MOD_ADD, dclevel, dn));
}

/*
 * smb_ads_modify_computer
 *
 * Returns 0 upon success. Otherwise, returns -1.
 */
static int
smb_ads_modify_computer(smb_ads_handle_t *ah, int dclevel, char *dn)
{
    return (smb_ads_computer_op(ah, LDAP_MOD_REPLACE, dclevel, dn));
}

/*
 * smb_ads_get_dc_level
 *
 * Returns the functional level of the DC upon success.
 * Otherwise, -1 is returned.
 */
static int
smb_ads_get_dc_level(smb_ads_handle_t *ah)
{
    LDAPMessage *res, *entry;
    char *attr[2];
    char **vals;
    int rc = -1;

    res = NULL;
    attr[0] = SMB_ADS_ATTR_DCLEVEL;
    attr[1] = NULL;
    if (ldap_search_s(ah->ld, "", LDAP_SCOPE_BASE, NULL, attr,
        0, &res) != LDAP_SUCCESS) {
        (void) ldap_msgfree(res);
        return (-1);
    }

    /* no match for the specified attribute is found */
    if (ldap_count_entries(ah->ld, res) == 0) {
        (void) ldap_msgfree(res);
        return (-1);
    }

    entry = ldap_first_entry(ah->ld, res);
    if (entry) {
        if ((vals = ldap_get_values(ah->ld, entry,
            SMB_ADS_ATTR_DCLEVEL)) == NULL) {
            /*
             * Observed the values aren't populated
             * by the Windows 2000 server.
             */
            (void) ldap_msgfree(res);
            return (SMB_ADS_DCLEVEL_W2K);
        }

        if (vals[0] != NULL)
            rc = atoi(vals[0]);

        ldap_value_free(vals);
    }

    (void) ldap_msgfree(res);
    return (rc);
}

static int
smb_ads_getfqhostname(smb_ads_handle_t *ah, char *fqhost, int len)
{
    if (smb_gethostname(fqhost, len, 0) != 0)
        return (-1);

    (void) snprintf(fqhost, len, "%s.%s", fqhost,
        ah->domain);

    return (0);
}

static int
smb_ads_computer_op(smb_ads_handle_t *ah, int op, int dclevel, char *dn)
{
    LDAPMod *attrs[SMB_ADS_COMPUTER_NUM_ATTR];
    char *sam_val[2], *usr_val[2];
    char *spn_set[SMBKRB5_SPN_IDX_MAX + 1], *ctl_val[2], *fqh_val[2];
    char *encrypt_val[2];
    int j = -1;
    int ret, usrctl_flags = 0;
    char sam_acct[SMB_SAMACCT_MAXLEN];
    char fqhost[MAXHOSTNAMELEN];
    char *user_principal;
    char usrctl_buf[16];
    char encrypt_buf[16];
    int max;

    if (smb_getsamaccount(sam_acct, sizeof (sam_acct)) != 0)
        return (-1);

    if (smb_ads_getfqhostname(ah, fqhost, MAXHOSTNAMELEN))
        return (-1);

    if (smb_ads_get_spnset(fqhost, spn_set) != 0)
        return (-1);

    user_principal = smb_krb5_get_upn(spn_set[SMBKRB5_SPN_IDX_HOST],
        ah->domain);

    if (user_principal == NULL) {
        smb_ads_free_spnset(spn_set);
        return (-1);
    }

    max = (SMB_ADS_COMPUTER_NUM_ATTR - ((op != LDAP_MOD_ADD) ? 1 : 0))
        - (dclevel >= SMB_ADS_DCLEVEL_W2K8 ?  0 : 1);

    if (smb_ads_alloc_attr(attrs, max) != 0) {
        free(user_principal);
        smb_ads_free_spnset(spn_set);
        return (-1);
    }

    /* objectClass attribute is not modifiable. */
    if (op == LDAP_MOD_ADD) {
        attrs[++j]->mod_op = op;
        attrs[j]->mod_type = "objectClass";
        attrs[j]->mod_values = smb_ads_computer_objcls;
    }

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_SAMACCT;
    sam_val[0] = sam_acct;
    sam_val[1] = 0;
    attrs[j]->mod_values = sam_val;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_UPN;
    usr_val[0] = user_principal;
    usr_val[1] = 0;
    attrs[j]->mod_values = usr_val;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_SPN;
    attrs[j]->mod_values = spn_set;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_CTL;
    usrctl_flags |= (SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT |
        SMB_ADS_USER_ACCT_CTL_PASSWD_NOTREQD |
        SMB_ADS_USER_ACCT_CTL_ACCOUNTDISABLE);
    (void) snprintf(usrctl_buf, sizeof (usrctl_buf), "%d", usrctl_flags);
    ctl_val[0] = usrctl_buf;
    ctl_val[1] = 0;
    attrs[j]->mod_values = ctl_val;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_DNSHOST;
    fqh_val[0] = fqhost;
    fqh_val[1] = 0;
    attrs[j]->mod_values = fqh_val;

    /* enctypes support starting in Windows Server 2008 */
    if (dclevel > SMB_ADS_DCLEVEL_W2K3) {
        attrs[++j]->mod_op = op;
        attrs[j]->mod_type = SMB_ADS_ATTR_ENCTYPES;
        (void) snprintf(encrypt_buf, sizeof (encrypt_buf), "%d",
            SMB_ADS_ENC_AES256 + SMB_ADS_ENC_AES128 + SMB_ADS_ENC_RC4 +
            SMB_ADS_ENC_DES_MD5 + SMB_ADS_ENC_DES_CRC);
        encrypt_val[0] = encrypt_buf;
        encrypt_val[1] = 0;
        attrs[j]->mod_values = encrypt_val;
    }

    switch (op) {
    case LDAP_MOD_ADD:
        if ((ret = ldap_add_s(ah->ld, dn, attrs)) != LDAP_SUCCESS) {
            syslog(LOG_NOTICE, "ldap_add: %s",
                ldap_err2string(ret));
            ret = -1;
        }
        break;

    case LDAP_MOD_REPLACE:
        if ((ret = ldap_modify_s(ah->ld, dn, attrs)) != LDAP_SUCCESS) {
            syslog(LOG_NOTICE, "ldap_modify: %s",
                ldap_err2string(ret));
            ret = -1;
        }
        break;

    default:
        ret = -1;

    }

    smb_ads_free_attr(attrs);
    free(user_principal);
    smb_ads_free_spnset(spn_set);

    return (ret);
}

/*
 * Delete an ADS computer account.
 */
static void
smb_ads_del_computer(smb_ads_handle_t *ah, char *dn)
{
    int rc;

    if ((rc = ldap_delete_s(ah->ld, dn)) != LDAP_SUCCESS)
        smb_tracef("ldap_delete: %s", ldap_err2string(rc));
}

/*
 * Gets the value of the given attribute.
 */
static smb_ads_qstat_t
smb_ads_getattr(LDAP *ld, LDAPMessage *entry, smb_ads_avpair_t *avpair)
{
    char **vals;
    smb_ads_qstat_t rc = SMB_ADS_STAT_FOUND;

    assert(avpair);
    avpair->avp_val = NULL;
    vals = ldap_get_values(ld, entry, avpair->avp_attr);
    if (!vals)
        return (SMB_ADS_STAT_NOT_FOUND);

    if (!vals[0]) {
        ldap_value_free(vals);
        return (SMB_ADS_STAT_NOT_FOUND);
    }

    avpair->avp_val = strdup(vals[0]);
    if (!avpair->avp_val)
        rc = SMB_ADS_STAT_ERR;

    ldap_value_free(vals);
    return (rc);
}

/*
 * Process query's result.
 */
static smb_ads_qstat_t
smb_ads_get_qstat(smb_ads_handle_t *ah, LDAPMessage *res,
    smb_ads_avpair_t *avpair)
{
    char fqhost[MAXHOSTNAMELEN];
    smb_ads_avpair_t dnshost_avp;
    smb_ads_qstat_t rc = SMB_ADS_STAT_FOUND;
    LDAPMessage *entry;

    if (smb_ads_getfqhostname(ah, fqhost, MAXHOSTNAMELEN))
        return (SMB_ADS_STAT_ERR);

    if (ldap_count_entries(ah->ld, res) == 0)
        return (SMB_ADS_STAT_NOT_FOUND);

    if ((entry = ldap_first_entry(ah->ld, res)) == NULL)
        return (SMB_ADS_STAT_ERR);

    dnshost_avp.avp_attr = SMB_ADS_ATTR_DNSHOST;
    rc = smb_ads_getattr(ah->ld, entry, &dnshost_avp);

    switch (rc) {
    case SMB_ADS_STAT_FOUND:
        /*
         * Returns SMB_ADS_STAT_DUP to avoid overwriting
         * the computer account of another system whose
         * NetBIOS name collides with that of the current
         * system.
         */
        if (strcasecmp(dnshost_avp.avp_val, fqhost))
            rc = SMB_ADS_STAT_DUP;

        free(dnshost_avp.avp_val);
        break;

    case SMB_ADS_STAT_NOT_FOUND:
        /*
         * Pre-created computer account doesn't have
         * the dNSHostname attribute. It's been observed
         * that the dNSHostname attribute is only set after
         * a successful domain join.
         * Returns SMB_ADS_STAT_FOUND as the account is
         * pre-created for the current system.
         */
        rc = SMB_ADS_STAT_FOUND;
        break;

    default:
        break;
    }

    if (rc != SMB_ADS_STAT_FOUND)
        return (rc);

    if (avpair)
        rc = smb_ads_getattr(ah->ld, entry, avpair);

    return (rc);

}

/*
 * smb_ads_lookup_computer_n_attr
 *
 * If avpair is NULL, checks the status of the specified computer account.
 * Otherwise, looks up the value of the specified computer account's attribute.
 * If found, the value field of the avpair will be allocated and set. The
 * caller should free the allocated buffer.
 *
 * Return:
 *  SMB_ADS_STAT_FOUND  - if both the computer and the specified attribute is
 *                        found.
 *  SMB_ADS_STAT_NOT_FOUND - if either the computer or the specified attribute
 *                           is not found.
 *  SMB_ADS_STAT_DUP - if the computer account is already used by other systems
 *                     in the AD. This could happen if the hostname of multiple
 *                     systems resolved to the same NetBIOS name.
 *  SMB_ADS_STAT_ERR - any failure.
 */
static smb_ads_qstat_t
smb_ads_lookup_computer_n_attr(smb_ads_handle_t *ah, smb_ads_avpair_t *avpair,
    int scope, char *dn)
{
    char *attrs[3], filter[SMB_ADS_MAXBUFLEN];
    LDAPMessage *res;
    char sam_acct[SMB_SAMACCT_MAXLEN], sam_acct2[SMB_SAMACCT_MAXLEN];
    smb_ads_qstat_t rc;

    if (smb_getsamaccount(sam_acct, sizeof (sam_acct)) != 0)
        return (SMB_ADS_STAT_ERR);

    res = NULL;
    attrs[0] = SMB_ADS_ATTR_DNSHOST;
    attrs[1] = NULL;
    attrs[2] = NULL;

    if (avpair) {
        if (!avpair->avp_attr)
            return (SMB_ADS_STAT_ERR);

        attrs[1] = avpair->avp_attr;
    }

    if (smb_ads_escape_search_filter_chars(sam_acct, sam_acct2) != 0)
        return (SMB_ADS_STAT_ERR);

    (void) snprintf(filter, sizeof (filter),
        "(&(objectClass=computer)(%s=%s))", SMB_ADS_ATTR_SAMACCT,
        sam_acct2);

    if (ldap_search_s(ah->ld, dn, scope, filter, attrs, 0,
        &res) != LDAP_SUCCESS) {
        (void) ldap_msgfree(res);
        return (SMB_ADS_STAT_NOT_FOUND);
    }

    rc = smb_ads_get_qstat(ah, res, avpair);
    /* free the search results */
    (void) ldap_msgfree(res);
    return (rc);
}

/*
 * smb_ads_find_computer
 *
 * Starts by searching for the system's AD computer object in the default
 * container (i.e. cn=Computers).  If not found, searches the entire directory.
 * If found, 'dn' will be set to the distinguished name of the system's AD
 * computer object.
 */
static smb_ads_qstat_t
smb_ads_find_computer(smb_ads_handle_t *ah, char *dn)
{
    smb_ads_qstat_t stat;
    smb_ads_avpair_t avpair;

    avpair.avp_attr = SMB_ADS_ATTR_DN;
    smb_ads_get_default_comp_container_dn(ah, dn, SMB_ADS_DN_MAX);
    stat = smb_ads_lookup_computer_n_attr(ah, &avpair, LDAP_SCOPE_ONELEVEL,
        dn);

    if (stat == SMB_ADS_STAT_NOT_FOUND) {
        (void) strlcpy(dn, ah->domain_dn, SMB_ADS_DN_MAX);
        stat = smb_ads_lookup_computer_n_attr(ah, &avpair,
            LDAP_SCOPE_SUBTREE, dn);
    }

    if (stat == SMB_ADS_STAT_FOUND) {
        (void) strlcpy(dn, avpair.avp_val, SMB_ADS_DN_MAX);
        free(avpair.avp_val);
    }

    return (stat);
}

/*
 * smb_ads_update_computer_cntrl_attr
 *
 * Modify the user account control attribute of an existing computer
 * object on AD.
 *
 * Returns LDAP error code.
 */
static int
smb_ads_update_computer_cntrl_attr(smb_ads_handle_t *ah, int flags, char *dn)
{
    LDAPMod *attrs[2];
    char *ctl_val[2];
    int ret = 0;
    char usrctl_buf[16];

    if (smb_ads_alloc_attr(attrs, sizeof (attrs) / sizeof (LDAPMod *)) != 0)
        return (LDAP_NO_MEMORY);

    attrs[0]->mod_op = LDAP_MOD_REPLACE;
    attrs[0]->mod_type = SMB_ADS_ATTR_CTL;

    (void) snprintf(usrctl_buf, sizeof (usrctl_buf), "%d", flags);
    ctl_val[0] = usrctl_buf;
    ctl_val[1] = 0;
    attrs[0]->mod_values = ctl_val;
    if ((ret = ldap_modify_s(ah->ld, dn, attrs)) != LDAP_SUCCESS) {
        syslog(LOG_NOTICE, "ldap_modify: %s", ldap_err2string(ret));
    }

    smb_ads_free_attr(attrs);
    return (ret);
}

/*
 * smb_ads_lookup_computer_attr_kvno
 *
 * Lookup the value of the Kerberos version number attribute of the computer
 * account.
 */
static krb5_kvno
smb_ads_lookup_computer_attr_kvno(smb_ads_handle_t *ah, char *dn)
{
    smb_ads_avpair_t avpair;
    int kvno = 1;

    avpair.avp_attr = SMB_ADS_ATTR_KVNO;
    if (smb_ads_lookup_computer_n_attr(ah, &avpair,
        LDAP_SCOPE_BASE, dn) == SMB_ADS_STAT_FOUND) {
        kvno = atoi(avpair.avp_val);
        free(avpair.avp_val);
    }

    return (kvno);
}

/*
 * smb_ads_gen_machine_passwd
 *
 * Returned a null-terminated machine password generated randomly
 * from [0-9a-zA-Z] character set. In order to pass the password
 * quality check (three character classes), an uppercase letter is
 * used as the first character of the machine password.
 */
static void
smb_ads_gen_machine_passwd(char *machine_passwd, int bufsz)
{
    char *data = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJK"
        "LMNOPQRSTUVWXYZ";
    int datalen = strlen(data);
    int i, data_idx;

    assert(machine_passwd);
    assert(bufsz > 0);

    /*
     * The decimal value of upper case 'A' is 65. Randomly pick
     * an upper-case letter from the ascii table.
     */
    machine_passwd[0] = (random() % 26) + 65;
    for (i = 1; i < bufsz - 1; i++) {
        data_idx = random() % datalen;
        machine_passwd[i] = data[data_idx];
    }

    machine_passwd[bufsz - 1] = 0;
}

/*
 * smb_ads_join
 *
 * Besides the NT-4 style domain join (using MS-RPC), CIFS server also
 * provides the domain join using Kerberos Authentication, Keberos
 * Change & Set password, and LDAP protocols. Basically, AD join
 * operation would require the following tickets to be acquired for the
 * the user account that is provided for the domain join.
 *
 * 1) a Keberos TGT ticket,
 * 2) a ldap service ticket, and
 * 3) kadmin/changpw service ticket
 *
 * The ADS client first sends a ldap search request to find out whether
 * or not the workstation trust account already exists in the Active Directory.
 * The existing computer object for this workstation will be removed and
 * a new one will be added. The machine account password is randomly
 * generated and set for the newly created computer object using KPASSWD
 * protocol (See RFC 3244). Once the password is set, our ADS client
 * finalizes the machine account by modifying the user acount control
 * attribute of the computer object. Kerberos keys derived from the machine
 * account password will be stored locally in /etc/krb5/krb5.keytab file.
 * That would be needed while acquiring Kerberos TGT ticket for the host
 * principal after the domain join operation.
 */
smb_adjoin_status_t
smb_ads_join(char *domain, char *user, char *usr_passwd, char *machine_passwd,
    int len)
{
    smb_ads_handle_t *ah = NULL;
    krb5_context ctx = NULL;
    krb5_principal krb5princs[SMBKRB5_SPN_IDX_MAX];
    krb5_kvno kvno;
    boolean_t des_only, delete = B_TRUE;
    smb_adjoin_status_t rc = SMB_ADJOIN_SUCCESS;
    boolean_t new_acct;
    int dclevel, num, usrctl_flags = 0;
    smb_ads_qstat_t qstat;
    char dn[SMB_ADS_DN_MAX];
    char *tmpfile;

    /*
     * Call library functions that can be used to get
     * the list of encryption algorithms available on the system.
     * (similar to what 'encrypt -l' CLI does). For now,
     * unless someone has modified the configuration of the
     * cryptographic framework (very unlikely), the following is the
     * list of algorithms available on any system running Nevada
     * by default.
     */
    krb5_enctype w2k8enctypes[] = {ENCTYPE_AES256_CTS_HMAC_SHA1_96,
        ENCTYPE_AES128_CTS_HMAC_SHA1_96, ENCTYPE_ARCFOUR_HMAC,
        ENCTYPE_DES_CBC_CRC, ENCTYPE_DES_CBC_MD5,
    };

    krb5_enctype pre_w2k8enctypes[] = {ENCTYPE_ARCFOUR_HMAC,
        ENCTYPE_DES_CBC_CRC, ENCTYPE_DES_CBC_MD5,
    };

    krb5_enctype *encptr;

    if ((ah = smb_ads_open_main(domain, user, usr_passwd)) == NULL) {
        smb_ccache_remove(SMB_CCACHE_PATH);
        return (SMB_ADJOIN_ERR_GET_HANDLE);
    }

    smb_ads_gen_machine_passwd(machine_passwd, len);

    if ((dclevel = smb_ads_get_dc_level(ah)) == -1) {
        smb_ads_close(ah);
        smb_ccache_remove(SMB_CCACHE_PATH);
        return (SMB_ADJOIN_ERR_GET_DCLEVEL);
    }

    qstat = smb_ads_find_computer(ah, dn);
    switch (qstat) {
    case SMB_ADS_STAT_FOUND:
        new_acct = B_FALSE;
        if (smb_ads_modify_computer(ah, dclevel, dn) != 0) {
            smb_ads_close(ah);
            smb_ccache_remove(SMB_CCACHE_PATH);
            return (SMB_ADJOIN_ERR_MOD_TRUST_ACCT);
        }
        break;

    case SMB_ADS_STAT_NOT_FOUND:
        new_acct = B_TRUE;
        smb_ads_get_default_comp_dn(ah, dn, SMB_ADS_DN_MAX);
        if (smb_ads_add_computer(ah, dclevel, dn) != 0) {
            smb_ads_close(ah);
            smb_ccache_remove(SMB_CCACHE_PATH);
            return (SMB_ADJOIN_ERR_ADD_TRUST_ACCT);
        }
        break;

    default:
        if (qstat == SMB_ADS_STAT_DUP)
            rc = SMB_ADJOIN_ERR_DUP_TRUST_ACCT;
        else
            rc = SMB_ADJOIN_ERR_TRUST_ACCT;
        smb_ads_close(ah);
        smb_ccache_remove(SMB_CCACHE_PATH);
        return (rc);
    }

    des_only = B_FALSE;

    if (smb_krb5_ctx_init(&ctx) != 0) {
        rc = SMB_ADJOIN_ERR_INIT_KRB_CTX;
        goto adjoin_cleanup;
    }

    if (smb_krb5_get_principals(ah->domain, ctx, krb5princs) != 0) {
        rc = SMB_ADJOIN_ERR_GET_SPNS;
        goto adjoin_cleanup;
    }

    if (smb_krb5_setpwd(ctx, krb5princs[SMBKRB5_SPN_IDX_HOST],
        machine_passwd) != 0) {
        rc = SMB_ADJOIN_ERR_KSETPWD;
        goto adjoin_cleanup;
    }

    kvno = smb_ads_lookup_computer_attr_kvno(ah, dn);

    /*
     * Only members of Domain Admins and Enterprise Admins can set
     * the TRUSTED_FOR_DELEGATION userAccountControl flag.
     */
    if (smb_ads_update_computer_cntrl_attr(ah,
        SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT |
        SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION, dn)
        == LDAP_INSUFFICIENT_ACCESS) {
        usrctl_flags |= (SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT |
            SMB_ADS_USER_ACCT_CTL_DONT_EXPIRE_PASSWD);

        syslog(LOG_NOTICE, "Unable to set the "
            "TRUSTED_FOR_DELEGATION userAccountControl flag on "
            "the machine account in Active Directory.  Please refer "
            "to the Troubleshooting guide for more information.");

    } else {
        usrctl_flags |= (SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT |
            SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION |
            SMB_ADS_USER_ACCT_CTL_DONT_EXPIRE_PASSWD);
    }

    if (des_only)
        usrctl_flags |= SMB_ADS_USER_ACCT_CTL_USE_DES_KEY_ONLY;

    if (smb_ads_update_computer_cntrl_attr(ah, usrctl_flags, dn)
        != 0) {
        rc = SMB_ADJOIN_ERR_UPDATE_CNTRL_ATTR;
        goto adjoin_cleanup;
    }

    if (dclevel >= SMB_ADS_DCLEVEL_W2K8) {
        num = sizeof (w2k8enctypes) / sizeof (krb5_enctype);
        encptr = w2k8enctypes;
    } else {
        num = sizeof (pre_w2k8enctypes) / sizeof (krb5_enctype);
        encptr = pre_w2k8enctypes;
    }

    tmpfile = mktemp(SMBNS_KRB5_KEYTAB_TMP);
    if (tmpfile == NULL)
        tmpfile = SMBNS_KRB5_KEYTAB_TMP;

    if (smb_krb5_add_keytab_entries(ctx, krb5princs, tmpfile,
        kvno, machine_passwd, encptr, num) != 0) {
        rc = SMB_ADJOIN_ERR_WRITE_KEYTAB;
        goto adjoin_cleanup;
    }

    delete = B_FALSE;
adjoin_cleanup:
    if (new_acct && delete)
        smb_ads_del_computer(ah, dn);

    if (rc != SMB_ADJOIN_ERR_INIT_KRB_CTX) {
        if (rc != SMB_ADJOIN_ERR_GET_SPNS)
            smb_krb5_free_principals(ctx, krb5princs,
                SMBKRB5_SPN_IDX_MAX);
        smb_krb5_ctx_fini(ctx);
    }

    /* commit keytab file */
    if (rc == SMB_ADJOIN_SUCCESS) {
        if (rename(tmpfile, SMBNS_KRB5_KEYTAB) != 0) {
            (void) unlink(tmpfile);
            rc = SMB_ADJOIN_ERR_COMMIT_KEYTAB;
        } else {
            /* Set IDMAP config */
            if (smb_config_set_idmap_domain(ah->domain) != 0) {
                rc = SMB_ADJOIN_ERR_IDMAP_SET_DOMAIN;
            } else {

                /* Refresh IDMAP service */
                if (smb_config_refresh_idmap() != 0)
                    rc = SMB_ADJOIN_ERR_IDMAP_REFRESH;
            }
        }
    } else {
        (void) unlink(tmpfile);
    }

    smb_ads_close(ah);
    smb_ccache_remove(SMB_CCACHE_PATH);
    return (rc);
}

/*
 * smb_ads_join_errmsg
 *
 * Display error message for the specific adjoin error code.
 */
void
smb_ads_join_errmsg(smb_adjoin_status_t status)
{
    int i;
    struct xlate_table {
        smb_adjoin_status_t status;
        char *msg;
    } adjoin_table[] = {
        { SMB_ADJOIN_ERR_GET_HANDLE, "Failed to connect to an "
            "Active Directory server." },
        { SMB_ADJOIN_ERR_GET_DCLEVEL, "Unknown functional level of "
            "the domain controller. The rootDSE attribute named "
            "\"domainControllerFunctionality\" is missing from the "
            "Active Directory." },
        { SMB_ADJOIN_ERR_ADD_TRUST_ACCT, "Failed to create the "
            "workstation trust account." },
        { SMB_ADJOIN_ERR_MOD_TRUST_ACCT, "Failed to modify the "
            "workstation trust account." },
        { SMB_ADJOIN_ERR_DUP_TRUST_ACCT, "Failed to create the "
            "workstation trust account because its name is already "
            "in use." },
        { SMB_ADJOIN_ERR_TRUST_ACCT, "Error in querying the "
            "workstation trust account" },
        { SMB_ADJOIN_ERR_INIT_KRB_CTX, "Failed to initialize Kerberos "
            "context." },
        { SMB_ADJOIN_ERR_GET_SPNS, "Failed to get Kerberos "
            "principals." },
        { SMB_ADJOIN_ERR_KSETPWD, "Failed to set machine password." },
        { SMB_ADJOIN_ERR_UPDATE_CNTRL_ATTR,  "Failed to modify "
            "userAccountControl attribute of the workstation trust "
            "account." },
        { SMB_ADJOIN_ERR_WRITE_KEYTAB, "Error in writing to local "
            "keytab file (i.e /etc/krb5/krb5.keytab)." },
        { SMB_ADJOIN_ERR_IDMAP_SET_DOMAIN, "Failed to update idmap "
            "configuration." },
        { SMB_ADJOIN_ERR_IDMAP_REFRESH, "Failed to refresh idmap "
            "service." },
        { SMB_ADJOIN_ERR_COMMIT_KEYTAB, "Failed to commit changes to "
            "local keytab file (i.e. /etc/krb5/krb5.keytab)." }
    };

    for (i = 0; i < sizeof (adjoin_table) / sizeof (adjoin_table[0]); i++) {
        if (adjoin_table[i].status == status)
            syslog(LOG_NOTICE, "%s", adjoin_table[i].msg);
    }
}

/*
 * smb_ads_match_pdc
 *
 * Returns B_TRUE if the given host's IP address matches the preferred DC's
 * IP address. Otherwise, returns B_FALSE.
 */
static boolean_t
smb_ads_match_pdc(smb_ads_host_info_t *host)
{
    boolean_t match = B_FALSE;

    if (!host)
        return (match);

    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    if (smb_inet_equal(&host->ipaddr, &smb_ads_cfg.c_pdc))
        match = B_TRUE;
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    return (match);
}

/*
 * smb_ads_select_dcfromsubnet
 *
 * This method walks the list of DCs and returns the first DC record that
 * responds to ldap ping and is in the same subnet as the host.
 *
 * Returns a pointer to the found DC record.
 * Returns NULL, on error or if no DC record is found.
 */
static smb_ads_host_info_t *
smb_ads_select_dcfromsubnet(smb_ads_host_list_t *hlist)
{
    smb_ads_host_info_t *hentry;
    smb_nic_t *lnic;
    smb_niciter_t ni;
    size_t cnt;
    int i;

    if (smb_nic_getfirst(&ni) != 0)
        return (NULL);
    do {
        lnic = &ni.ni_nic;
        cnt = hlist->ah_cnt;

        for (i = 0; i < cnt; i++) {
            hentry = &hlist->ah_list[i];
            if ((hentry->ipaddr.a_family == AF_INET) &&
                (lnic->nic_ip.a_family == AF_INET)) {
                if ((hentry->ipaddr.a_ipv4 &
                    lnic->nic_mask) ==
                    (lnic->nic_ip.a_ipv4 &
                    lnic->nic_mask))
                    if (smb_ads_ldap_ping(hentry) == 0)
                        return (hentry);
            }
        }
    } while (smb_nic_getnext(&ni) == 0);

    return (NULL);
}

/*
 * smb_ads_select_dcfromlist
 *
 * This method walks the list of DCs and returns the first DC that
 * responds to ldap ping.
 *
 * Returns a pointer to the found DC record.
 * Returns NULL if no DC record is found.
 */
static smb_ads_host_info_t *
smb_ads_select_dcfromlist(smb_ads_host_list_t *hlist)
{
    smb_ads_host_info_t *hentry;
    size_t cnt;
    int i;

    cnt = hlist->ah_cnt;
    for (i = 0; i < cnt; i++) {
        hentry = &hlist->ah_list[i];
        if (smb_ads_ldap_ping(hentry) == 0)
            return (hentry);
    }

    return (NULL);
}

/*
 * smb_ads_dc_compare
 *
 * Comparision function for sorting host entries (SRV records of DC) via qsort.
 * RFC 2052/2782 are taken as reference, while implementing this algorithm.
 *
 * Domain Controllers(DCs) with lowest priority in their SRV DNS records
 * are selected first. If they have equal priorities, then DC with highest
 * weight in its SRV DNS record is selected. If the priority and weight are
 * both equal, then the DC at the top of the list is selected.
 */
static int
smb_ads_dc_compare(const void *p, const void *q)
{
    smb_ads_host_info_t *h1 = (smb_ads_host_info_t *)p;
    smb_ads_host_info_t *h2 = (smb_ads_host_info_t *)q;

    if (h1->priority < h2->priority)
        return (-1);
    if (h1->priority > h2->priority)
        return (1);

    /* Priorities are equal */
    if (h1->weight < h2->weight)
        return (1);
    if (h1->weight > h2->weight)
        return (-1);

    return (0);
}

/*
 * smb_ads_select_dc
 *
 * The list of ADS hosts returned by ADS lookup, is sorted by lowest priority
 * and highest weight. On this sorted list, following additional rules are
 * applied, to select a DC.
 *
 *  - If there is a DC in the same subnet, then return the DC,
 *    if it responds to ldap ping.
 *  - Else, return first DC that responds to ldap ping.
 *
 * A reference to the host entry from input host list is returned.
 *
 * Returns NULL on error.
 */
static smb_ads_host_info_t *
smb_ads_select_dc(smb_ads_host_list_t *hlist)
{
    smb_ads_host_info_t *hentry = NULL;

    if (hlist->ah_cnt == 0)
        return (NULL);

    if (hlist->ah_cnt == 1) {
        hentry = hlist->ah_list;
        if (smb_ads_ldap_ping(hentry) == 0)
            return (hentry);
    }

    /* Sort the list by priority and weight */
    qsort(hlist->ah_list, hlist->ah_cnt,
        sizeof (smb_ads_host_info_t), smb_ads_dc_compare);

    if ((hentry = smb_ads_select_dcfromsubnet(hlist)) != NULL)
        return (hentry);

    if ((hentry = smb_ads_select_dcfromlist(hlist)) != NULL)
        return (hentry);

    return (NULL);
}

/*
 * smb_ads_lookup_msdcs
 *
 * If server argument is set, try to locate the specified DC.
 * If it is set to empty string, locate any DCs in the specified domain.
 * Returns the discovered DC via buf.
 *
 * fqdn   - fully-qualified domain name
 * server - fully-qualifed hostname of a DC
 * buf    - the hostname of the discovered DC
 */
boolean_t
smb_ads_lookup_msdcs(char *fqdn, char *server, char *buf, uint32_t buflen)
{
    smb_ads_host_info_t *hinfo = NULL;
    char *p;
    char *sought_host;
    char ipstr[INET6_ADDRSTRLEN];

    if (!fqdn || !buf)
        return (B_FALSE);

    ipstr[0] = '\0';
    *buf = '\0';
    sought_host = (*server == 0 ? NULL : server);
    if ((hinfo = smb_ads_find_host(fqdn, sought_host)) == NULL)
        return (B_FALSE);

    (void) smb_inet_ntop(&hinfo->ipaddr, ipstr,
        SMB_IPSTRLEN(hinfo->ipaddr.a_family));
    smb_tracef("msdcsLookupADS: %s [%s]", hinfo->name, ipstr);

    (void) strlcpy(buf, hinfo->name, buflen);
    /*
     * Remove the domain extension
     */
    if ((p = strchr(buf, '.')) != 0)
        *p = '\0';

    free(hinfo);
    return (B_TRUE);
}