8322 nl: misleading-indentation

[unleashed/tickless.git] / usr / src / lib / smbsrv / libsmbns / common / smbns_browser.c

/*
 * 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 (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/tzfile.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <syslog.h>
#include <string.h>
#include <strings.h>
#include <time.h>
#include <synch.h>
#include <netdb.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include <smbsrv/libsmb.h>
#include <smbsrv/libsmbns.h>
#include <smbsrv/smb.h>
#include <smbsrv/mailslot.h>
#include <smbns_browser.h>
#include <smbns_netbios.h>

/*
 * ntdomain_info
 * Temporary. It should be removed once NBTD is integrated.
 */
smb_ntdomain_t ntdomain_info;
mutex_t ntdomain_mtx;
cond_t ntdomain_cv;

#define SMB_SERVER_SIGNATURE            0xaa550415

typedef struct smb_hostinfo {
        list_node_t     hi_lnd;
        smb_nic_t       hi_nic;
        char            hi_nbname[NETBIOS_NAME_SZ];
        name_entry_t    hi_netname;
        uint32_t        hi_nextannouce;
        int             hi_reps;
        int             hi_interval;
        uint8_t         hi_updatecnt;
        uint32_t        hi_type;
        smb_version_t   hi_version;
} smb_hostinfo_t;

typedef struct smb_browserinfo {
        list_t          bi_hlist;
        int             bi_hcnt;
        rwlock_t        bi_hlist_rwl;
        boolean_t       bi_changed;
        mutex_t         bi_mtx;
} smb_browserinfo_t;

static smb_browserinfo_t smb_binfo;

static int smb_browser_init(void);
static void smb_browser_infoinit(void);
static void smb_browser_infoterm(void);
static void smb_browser_infofree(void);


void
smb_browser_reconfig(void)
{
        (void) mutex_lock(&smb_binfo.bi_mtx);
        smb_binfo.bi_changed = B_TRUE;
        (void) mutex_unlock(&smb_binfo.bi_mtx);
}

/*
 * 3. Browser Overview
 *
 * Hosts involved in the browsing process can be separated into two
 * distinct groups, browser clients and browser servers (often referred to
 * simply as "browsers").
 *
 * A browser is a server which maintains information about servers -
 * primarily the domain they are in and the services that they are running
 * -- and about domains. Browsers may assume several different roles in
 * their lifetimes, and dynamically switch between them.
 *
 *  Browser clients are of two types: workstations and (non-browser)
 * servers. In the context of browsing, workstations query browsers for the
 * information they contain; servers supply browsers the information by
 * registering with them. Note that, at times, browsers may themselves
 * behave as browser clients and query other browsers.
 *
 * For the purposes of this specification, a domain is simply a name with
 * which to associate a group of resources such as computers, servers and
 * users. Domains allow a convenient means for browser clients to restrict
 * the scope of a search when they query browser servers. Every domain has
 * a "master" server called the Primary Domain Controller (PDC) that
 * manages various  activities within the domain.
 *
 * One browser for each domain on a subnet is designated the Local Master
 * Browser for that domain. Servers in its domain on the subnet register
 * with it, as do the Local Master Browsers for other domains on the
 * subnet. It uses these registrations to maintain authoritative
 * information about its domain on its subnet. If there are other subnets
 * in the network, it also knows the name of the server running the
 * domain's Domain Master Browser; it registers with it, and uses it to
 * obtain information about the rest of the network (see below).
 *
 * Clients on a subnet query browsers designated as the Backup Browsers for
 * the subnet (not the Master Browser). Backup Browsers maintain a copy of
 * the information on the Local Master Browser; they get it by periodically
 * querying the Local Master Browser for all of its information. Clients
 * find the Backup Browsers by asking the Local Master Browser. Clients are
 * expected to spread their queries evenly across Backup Browsers to
 * balance the load.
 *
 * The Local Master Browser is dynamically elected automatically. Multiple
 * Backup Browser Servers may exist per subnet; they are selected from
 * among the potential browser servers by the Local Master Browser, which
 * is configured to select enough to handle the expected query load.
 *
 * When there are multiple subnets, a Domain Master Browser is assigned
 * the task of keeping the multiple subnets in synchronization. The Primary
 * Domain Controller (PDC) always acts as the Domain Master Browser. The
 * Domain Master Browser periodically acts as a client and queries all the
 * Local Master Browsers for its domain, asking them for a list containing
 * all the domains and all the servers in their domain known within their
 * subnets; it merges all the replies into a single master list. This
 * allows a Domain Master Browser server to act as a collection point for
 * inter-subnet browsing information. Local Master Browsers periodically
 * query the Domain Master Browser to retrieve the network-wide information
 * it maintains.
 *
 * When a domain spans only a single subnet, there will not be any distinct
 * Local Master Browser; this role will be handled by the Domain Master
 * Browser. Similarly, the Domain Master Browser is always the Local Master
 * Browser for the subnet it is on.
 *
 * When a browser client suspects that the Local Master Browser has failed,
 * the client will instigate an election in which the browser servers
 * participate, and some browser servers may change roles.
 *
 * Some characteristics of a good browsing mechanism include:
 * . minimal network traffic
 * . minimum server discovery time
 * . minimum change discovery latency
 * . immunity to machine failures
 *
 * Historically, Browser implementations had been very closely tied to
 * NETBIOS and datagrams. The early implementations caused a lot of
 * broadcast traffic. See Appendix D for an overview that presents how the
 * Browser specification evolved.
 *
 * 4. Browsing Protocol Architecture
 *
 * This section first describes the how the browsing protocol is layered,
 * then describes the roles of clients, servers, and browsers in the
 * browsing subsystem.
 *
 * 4.1 Layering of Browsing Protocol Requests
 *
 * Most of the browser functionality is implemented using mailslots.
 * Mailslots provide a mechanism for fast, unreliable unidirectional data
 * transfer; they are named via ASCII "mailslot (path) name". Mailslots are
 * implemented using the CIFS Transact SMB which is encapsulated in a
 * NETBIOS datagram. Browser protocol requests are sent to browser specific
 * mailslots using some browser-specific NETBIOS names. These datagrams can
 * either be unicast or broadcast, depending on whether the NETBIOS name is
 * a "unique name" or a "group name". Various data structures, which are
 * detailed subsequently within this document, flow as the data portion of
 * the Transact SMB.
 *
 * Here is an example of a generic browser SMB, showing how a browser
 * request is encapsulated in a TRANSACT SMB request. Note that the PID,
 * TID, MID, UID, and Flags are all 0 in mailslot requests.
 *
 * SMB: C transact, File = \MAILSLOT\BROWSE
 *   SMB: SMB Status = Error Success
 *     SMB: Error class = No Error
 *     SMB: Error code = No Error
 *   SMB: Header: PID = 0x0000 TID = 0x0000 MID = 0x0000 UID = 0x0000
 *     SMB: Tree ID   (TID) = 0 (0x0)
 *     SMB: Process ID  (PID) = 0 (0x0)
 *     SMB: User ID   (UID) = 0 (0x0)
 *     SMB: Multiplex ID (MID) = 0 (0x0)
 *     SMB: Flags Summary = 0 (0x0)
 *   SMB: Command = C transact
 *     SMB: Word count = 17
 *     SMB: Word parameters
 *     SMB: Total parm bytes = 0
 *     SMB: Total data bytes = 33
 *     SMB: Max parm bytes = 0
 *     SMB: Max data bytes = 0
 *     SMB: Max setup words = 0
 *     SMB: Transact Flags Summary = 0 (0x0)
 *       SMB: ...............0 = Leave session intact
 *       SMB: ..............0. = Response required
 *     SMB: Transact timeout = 0 (0x0)
 *     SMB: Parameter bytes = 0 (0x0)
 *     SMB: Parameter offset = 0 (0x0)
 *     SMB: Data bytes = 33 (0x21)
 *     SMB: Data offset = 86 (0x56)
 *     SMB: Setup word count = 3
 *     SMB: Setup words
 *     SMB: Mailslot opcode = Write mailslot
 *     SMB: Transaction priority = 1
 *     SMB: Mailslot class = Unreliable (broadcast)
 *     SMB: Byte count = 50
 *     SMB: Byte parameters
 *     SMB: Path name = \MAILSLOT\BROWSE
 *     SMB: Transaction data
 *   SMB: Data: Number of data bytes remaining = 33 (0x0021)
 *
 * Note the SMB command is Transact, the opcode within the Transact SMB is
 * Mailslot Write, and the browser data structure is carried as the
 * Transact data.
 * The Transaction data begins with an opcode, that signifies the operation
 * and determines the size and structure of data that follows. This opcode
 * is named as per one of the below:
 *
 * HostAnnouncement         1
 * AnnouncementRequest      2
 * RequestElection          8
 * GetBackupListReq         9
 * GetBackupListResp        10
 * BecomeBackup             11
 * DomainAnnouncment        12
 * MasterAnnouncement       13
 * LocalMasterAnnouncement  15
 *
 * Browser datagrams are often referred to as simply browser frames. The
 * frames are in particular, referred to by the name of the opcode within
 * the Transaction data e.g. a GetBackupListReq browser frame, a
 * RequestElection browser frame, etc.
 *
 * The structures that are sent as the data portion of the Transact SMB are
 * described in section(s) 6.2 through 6.12 in this document. These
 * structures are tightly packed, i.e. there are no intervening pad bytes
 * in the structure, unless they are explicitly described as being there.
 * All quantities are sent in native Intel format and multi-byte values are
 * transmitted least significant byte first.
 *
 * Besides mailslots and Transaction SMBs, the other important piece of the
 * browser architecture is the NetServerEnum2 request. This request that
 * allows an application to interrogate a Browser Server and obtain a
 * complete list of resources (servers, domains, etc) known to that Browser
 * server. Details of the NetServerEnum2 request are presented in section
 * 6.4. Some examples of the NetServerEnum2 request being used are when a
 * Local Master Browser sends a NetServerEnum2 request to the Domain Master
 * Browser and vice versa. Another example is when a browser client sends a
 * NetServerEnum2 request to a Backup Browser server.
 *
 * 4.3 Non-Browser Server
 *
 * A non-browser server is a server that has some resource(s) or service(s)
 * it wishes to advertise as being available using the browsing protocol.
 * Examples of non-browser servers would be an SQL server, print server,
 * etc.
 *
 * A non-browser server MUST periodically send a HostAnnouncement browser
 * frame, specifying the type of resources or services it is advertising.
 * Details are in section 6.5.
 *
 * A non-browser server SHOULD announce itself relatively frequently when
 * it first starts up in order to make its presence quickly known to the
 * browsers and thence to potential clients. The frequency of the
 * announcements SHOULD then be gradually stretched, so as to minimize
 * network traffic. Typically,  non-browser servers announce themselves
 * once every minute upon start up and then gradually adjust the frequency
 * of the announcements to once every 12 minutes.
 *
 * A non-browser server SHOULD send a HostAnnouncement browser frame
 * specifying a type of  0 just prior to shutting down, to allow it to
 * quickly be removed from the list of available servers.
 *
 * A non-browser server MUST receive and process AnnouncementRequest frames
 * from the Local Master Browser, and MUST respond with a HostAnnouncement
 * frame, after a delay chosen randomly from the interval [0,30] seconds.
 * AnnouncementRequests typically happen when a Local Master Browser starts
 * up with an empty list of servers for the domain, and wants to fill it
 * quickly. The 30 second range for responses prevents the Master Browser
 * from becoming overloaded and losing replies, as well as preventing the
 * network from being flooded with responses.
 *
 * 4.4  Browser Servers
 *
 * The following sections describe the roles of the various types of
 * browser servers.
 *
 * 4.4.1  Potential Browser Server
 *
 * A Potential Browser server is a browser server that is capable of being
 * a Backup Browser server or Master Browser server, but is not currently
 * fulfilling either of those roles.
 *
 * A Potential Browser MUST set type SV_TYPE_POTENTIAL_BROWSER (see section
 * 6.4.1) in its HostAnnouncement until it is ready to shut down. In its
 * last HostAnnouncement frame before it shuts down, it SHOULD specify a
 * type of  0.
 *
 * A Potential Browser server MUST receive and process BecomeBackup frames
 * (see section 6.9) and become a backup browser upon their receipt.
 *
 * A Potential Browser MUST participate in browser elections (see section
 * 6.8).
 *
 * 4.4.2  Backup Browser
 *
 * Backup Browser servers are a subset of the Potential Browsers that have
 * been chosen by the Master Browser on their subnet to be the Backup
 * Browsers for the subnet.
 *
 * A Backup Browser MUST set type SV_TYPE_BACKUP_BROWSER (see section
 * 6.4.1) in its HostAnnouncement until it is ready to shut down. In its
 * last HostAnnouncement frame before it shuts down, it SHOULD specify a
 * type of  0.
 *
 * A Backup Browser MUST listen for a LocalMasterAnnouncement frame (see
 * section 6.10) from the Local Master Browser, and use it to set the name
 * of the Master Browser it queries for the server and domain lists.
 *
 * A  Backup Browsers MUST periodically make a NetServerEnum2 request of
 * the Master Browser on its subnet for its domain to get a list of servers
 * in that domain, as well as a list of domains. The period is a
 * configuration option balancing currency of the information with network
 * traffic costs - a typical value is 15 minutes.
 *
 * A Backup Browser SHOULD force an election by sending a RequestElection
 * frame (see section 6.7) if it does not get a response to its periodic
 * NetServeEnum2 request to the Master Browser.
 *
 * A Backup Browser MUST receive and process NetServerEnum2 requests from
 * browser clients, for its own domain and others. If the request is for a
 * list of servers in its domain, or for a list of domains, it can answer
 * from its internal lists. If the request is for a list of servers in a
 * domain different than the one it serves, it sends a NetServerEnum2
 * request to the Domain Master Browser for that domain (which it can in
 * find in its list of domains and their Domain Master Browsers).
 *
 * A Backup Browser MUST participate in browser elections (see section
 * 6.8).
 *
 * 4.4.3 Master Browser
 *
 * Master Browsers are responsible for:
 * . indicating it is a Master Browser
 * . receiving server announcements and building a list of such servers
 *   and keeping it reasonably up-to-date.
 * . returning lists of Backup Browsers to browser clients.
 * . ensuring an appropriate number of Backup Browsers are available.
 * . announcing their existence to other Master Browsers on their subnet,
 *   to the Domain Master Browser for their domain, and to all browsers in
 *   their domain on their subnet
 * . forwarding requests for lists of servers on other domains to the
 *   Master Browser for that domain
 * . keeping a list of domains in its subnet
 * . synchronizing with the Domain Master Browser (if any) for its domain
 * . participating in browser elections
 * . ensuring that there is only one Master Browser on its subnet
 *
 * A Master Browser MUST set type SV_TYPE_MASTER_BROWSER (see section
 * 6.4.1) in its HostAnnouncement until it is ready to shut down. In its
 * last HostAnnouncement frame before it shuts down, it SHOULD specify a
 * type of  0.
 *
 * A Master Browser MUST receive and process HostAnnouncement frames from
 * servers, adding the server name and other information to its servers
 * list; it must mark them as "local" entries. Periodically, it MUST check
 * all local server entries to see if a server's HostAnnouncement has timed
 * out (no HostAnnouncement received for three times the periodicity the
 * server gave in the last received HostAnnouncement) and remove timed-out
 * servers from its list.
 *
 * A Master Browser MUST receive and process DomainAnnouncement frames (see
 * section 6.12) and maintain the domain names and their associated (Local)
 * Master Browsers in its internal domain list until they time out; it must
 * mark these as "local" entries. Periodically, it MUST check all local
 * domain entries to see if a server's DomainAnnouncement has timed out (no
 * DomainAnnouncement received for three times the periodicity the server
 * gave in the last received DomainAnnouncement) and remove timed-out
 * servers from its list.
 *
 * A Master Browser MUST receive and process GetBackupListRequest frames
 * from clients, returning GetBackupListResponse frames containing a list
 * of the Backup Servers for its domain.
 *
 * A Master Browser MUST eventually send BecomeBackup frames (see section
 * 6.9) to one or more Potential Browser servers to increase the number of
 * Backup Browsers if there are not enough Backup Browsers to handle the
 * anticipated query load. Note: possible good times for checking for
 * sufficient backup browsers are after being elected, when timing out
 * server HostAnnouncements, and when receiving a server's HostAnnouncement
 * for the first time.
 *
 * A Master Browser MUST periodically announce itself and the domain it
 * serves to other (Local) Master Browsers on its subnet, by sending a
 * DomainAnnouncement frame (see section 6.12) to its subnet.
 *
 * A Master Browser MUST send a MasterAnnouncement frame (see section 6.11)
 * to the Domain Master Browser after it is first elected, and periodically
 * thereafter. This informs the Domain Master Browser of the presence of
 * all the Master Browsers.
 *
 * A Master Browser MUST periodically announce itself to all browsers for
 * its domain on its subnet by sending a LocalMasterAnnouncement frame (see
 * section 6.10).
 *
 * A Master Browser MUST receive and process NetServerEnum2 requests from
 * browser clients, for its own domain and others. If the request is for a
 * list of servers in its domain, or for a list of domains, it can answer
 * from its internal lists. Entries in its list marked "local" MUST have
 * the SV_TYPE_LOCAL_LIST_ONLY bit set in the returned results; it must be
 * clear for all other entries. If the request is for a list of servers in
 * a domain different than the one it serves, it sends a NetServerEnum2
 * request to the Domain Master Browser for that domain (which it can in
 * find in its list of domains and their Domain Master Browsers).
 *
 *     Note: The list of servers that the Master Browser maintains and
 *     returns to the Backup Browsers, is limited in size to 64K of
 *     data. This will limit the number of systems that can be in a
 *     browse list in a single workgroup or domain to approximately two
 *     thousand systems.
 *
 * A Master Browser SHOULD request all servers to register with it by
 * sending an AnnouncementRequest frame, if, on becoming the Master Browser
 * by winning an election, its server list is empty. Otherwise, clients
 * might get an incomplete list of servers until the servers' periodic
 * registrations fill the server list.
 *
 * If the Master Browser on a subnet is not the Primary Domain Controller
 * (PDC), then it is a Local Master Browser.
 *
 * A Local Master Browser MUST periodically synchronize with the Domain
 * Master Browser (which is the PDC). This synchronization is performed by
 * making a NetServerEnum2 request to the Domain Master Browser and merging
 * the results with its list of servers and domains. An entry from the
 * Domain Master Browser should be marked "non-local", and must not
 * overwrite an entry with the same name marked "local". The Domain Master
 * Browser is located as specified in Appendix B.
 *
 * A Master Browser MUST participate in browser elections (see section
 * 6.8).
 *
 * A Master Browser MUST, if it receives a HostAnnouncement,
 * DomainAnnouncement, or LocalMasterAnnouncement frame another system that
 * claims to be the Master Browser for its domain, demote itself from
 * Master Browser and force an election. This ensures that there is only
 * ever one Master Browser in each workgroup or domain.
 *
 * A Master Browser SHOULD, if it loses an election, become a Backup
 * Browser (without being told to do so by the new Master Browser). Since
 * it has more up-to-date information in its lists than a Potential
 * Browser, it is more efficient to have it be a Backup Browser than to
 * promote a Potential Browser.
 *
 * 4.4.3.1 Preferred Master Browser
 *
 * A Preferred Master Browser supports exactly the same protocol elements
 * as a Potential Browser, except as follows.
 *
 * A Preferred Master Browser MUST always force an election when it starts
 * up.
 *
 * A Preferred Master Browser MUST participate in browser elections (see
 * section 6.8).
 *
 * A Preferred Master Browser MUST set the Preferred Master bit in the
 * RequestElection frame (see section 6.7) to bias the election in its
 * favor.
 *
 * A Preferred Master Browser SHOULD, if it loses an election,
 * automatically become a Backup Browser, without being told to do so by
 * the Master Browser.
 *
 * 4.4.4 Domain Master Browser
 *
 * Since the Domain Master Browser always runs on the PDC, it must
 * implement all the protocols required of a PDC in addition to the
 * browsing protocol, and that is way beyond the scope of this
 * specification.
 *
 * 5. Mailslot Protocol Specification
 *
 * The only transaction allowed to a mailslot is a mailslot write. Mailslot
 * writes requests are encapsulated in TRANSACT SMBs. The following table
 * shows the interpretation of the TRANSACT SMB parameters for a mailslot
 * transaction:
 *
 *  Name            Value               Description
 *  Command         SMB_COM_TRANSACTION
 *  Name            <name>              STRING name of mail slot to write;
 *                                      must start with "\\MAILSLOT\\"
 *  SetupCount      3                   Always 3 for mailslot writes
 *  Setup[0]        1                   Command code == write mailslot
 *  Setup[1]        Ignored
 *  Setup[2]        Ignored
 *  TotalDataCount  n                   Size of data in bytes to write to
 *                                      the mailslot
 *  Data[ n ]                           The data to write to the mailslot
 *
 */

/*
 * SMB: C transact, File = \MAILSLOT\BROWSE
 *   SMB: SMB Status = Error Success
 *     SMB: Error class = No Error
 *     SMB: Error code = No Error
 *   SMB: Header: PID = 0x0000 TID = 0x0000 MID = 0x0000 UID = 0x0000
 *     SMB: Tree ID   (TID) = 0 (0x0)
 *     SMB: Process ID  (PID) = 0 (0x0)
 *     SMB: User ID   (UID) = 0 (0x0)
 *     SMB: Multiplex ID (MID) = 0 (0x0)
 *     SMB: Flags Summary = 0 (0x0)
 *   SMB: Command = C transact
 *     SMB: Word count = 17
 *     SMB: Word parameters
 *     SMB: Total parm bytes = 0
 *     SMB: Total data bytes = 33
 *     SMB: Max parm bytes = 0
 *     SMB: Max data bytes = 0
 *     SMB: Max setup words = 0
 *     SMB: Transact Flags Summary = 0 (0x0)
 *       SMB: ...............0 = Leave session intact
 *       SMB: ..............0. = Response required
 *     SMB: Transact timeout = 0 (0x0)
 *     SMB: Parameter bytes = 0 (0x0)
 *     SMB: Parameter offset = 0 (0x0)
 *     SMB: Data bytes = 33 (0x21)
 *     SMB: Data offset = 86 (0x56)
 *     SMB: Setup word count = 3
 *     SMB: Setup words
 *     SMB: Mailslot opcode = Write mailslot
 *     SMB: Transaction priority = 1
 *     SMB: Mailslot class = Unreliable (broadcast)
 *     SMB: Byte count = 50
 *     SMB: Byte parameters
 *     SMB: Path name = \MAILSLOT\BROWSE
 *     SMB: Transaction data
 *   SMB: Data: Number of data bytes remaining = 33 (0x0021)
 *
 * 5. Mailslot Protocol Specification
 *
 * The only transaction allowed to a mailslot is a mailslot write. Mailslot
 * writes requests are encapsulated in TRANSACT SMBs. The following table
 * shows the interpretation of the TRANSACT SMB parameters for a mailslot
 * transaction:
 *
 *  Name            Value               Description
 *  Command         SMB_COM_TRANSACTION
 *  Name            <name>              STRING name of mail slot to write;
 *                                      must start with "\MAILSLOT\"
 *  SetupCount      3                   Always 3 for mailslot writes
 *  Setup[0]        1                   Command code == write mailslot
 *  Setup[1]        Ignored
 *  Setup[2]        Ignored
 *  TotalDataCount  n                   Size of data in bytes to write to
 *                                      the mailslot
 *  Data[ n ]                           The data to write to the mailslot
 *
 *      Magic           0xFF 'S' 'M' 'B'
 *      smb_com         a byte, the "first" command
 *      Error           a 4-byte union, ignored in a request
 *      smb_flg         a one byte set of eight flags
 *      smb_flg2        a two byte set of 16 flags
 *      .               twelve reserved bytes, have a role
 *                      in connectionless transports (IPX, UDP?)
 *      smb_tid         a 16-bit tree ID, a mount point sorta,
 *                      0xFFFF is this command does not have
 *                      or require a tree context
 *      smb_pid         a 16-bit process ID
 *      smb_uid         a 16-bit user ID, specific to this "session"
 *                      and mapped to a system (bona-fide) UID
 *      smb_mid         a 16-bit multiplex ID, used to differentiate
 *                      multiple simultaneous requests from the same
 *                      process (pid) (ref RPC "xid")
 */

int
smb_browser_load_transact_header(unsigned char *buffer, int maxcnt,
    int data_count, int reply, char *mailbox)
{
        smb_msgbuf_t mb;
        int     mailboxlen;
        char *fmt;
        int result;
        short   class = (reply == ONE_WAY_TRANSACTION) ? 2 : 0;

        /*
         * If the mailboxlen is an even number we need to pad the
         * header so that the data starts on a word boundary.
         */
        fmt = "Mb4.bw20.bwwwwb.wl2.wwwwb.wwwws";
        mailboxlen = strlen(mailbox) + 1;

        if ((mailboxlen & 0x01) == 0) {
                ++mailboxlen;
                fmt = "Mb4.bw20.bwwwwb.wl2.wwwwb.wwwws.";
        }

        bzero(buffer, maxcnt);
        smb_msgbuf_init(&mb, buffer, maxcnt, 0);

        result = smb_msgbuf_encode(&mb, fmt,
            SMB_COM_TRANSACTION,        /* Command */
            0x18,
            0x3,
            17,                         /* Count of parameter words */
            0,                          /* Total Parameter words sent */
            data_count,                 /* Total Data bytes sent */
            2,                          /* Max Parameters to return */
            0,                          /* Max data bytes to return */
            0,                          /* Max setup bytes to return */
            reply,                      /* No reply */
            0xffffffff,                 /* Timeout */
            0,                          /* Parameter bytes sent */
            0,                          /* Parameter offset */
            data_count,                 /* Data bytes sent */
            69 + mailboxlen,            /* Data offset */
            3,                          /* Setup word count */
            1,                          /* Setup word[0] */
            0,                          /* Setup word[1] */
            class,                      /* Setup word[2] */
            mailboxlen + data_count,    /* Total request bytes */
            mailbox);                   /* Mailbox address */

        smb_msgbuf_term(&mb);
        return (result);
}

static int
smb_browser_addr_of_subnet(struct name_entry *name, smb_hostinfo_t *hinfo,
    struct name_entry *result)
{
        uint32_t ipaddr, mask, saddr;
        addr_entry_t *addr;

        if (name == NULL)
                return (-1);

        if (hinfo->hi_nic.nic_smbflags & SMB_NICF_ALIAS)
                return (-1);

        ipaddr = hinfo->hi_nic.nic_ip.a_ipv4;
        mask = hinfo->hi_nic.nic_mask;

        *result = *name;
        addr = &name->addr_list;
        do {
                saddr = addr->sin.sin_addr.s_addr;
                if ((saddr & mask) == (ipaddr & mask)) {
                        *result = *name;
                        result->addr_list = *addr;
                        result->addr_list.forw = result->addr_list.back =
                            &result->addr_list;
                        return (0);
                }
                addr = addr->forw;
        } while (addr != &name->addr_list);

        return (-1);
}


static int
smb_browser_bcast_addr_of_subnet(struct name_entry *name, uint32_t bcast,
    struct name_entry *result)
{
        if (name != NULL && name != result)
                *result = *name;

        result->addr_list.sin.sin_family = AF_INET;
        result->addr_list.sinlen = sizeof (result->addr_list.sin);
        result->addr_list.sin.sin_addr.s_addr = bcast;
        result->addr_list.sin.sin_port = htons(IPPORT_NETBIOS_DGM);
        result->addr_list.forw = result->addr_list.back = &result->addr_list;
        return (0);
}

/*
 * 6.5 HostAnnouncement Browser Frame
 *
 * To advertise its presence, i.e. to publish itself as being available, a
 * non-browser server sends a HostAnnouncement browser frame. If the server
 * is a member of domain "D", this frame is sent to the NETBIOS unique name
 * D(1d) and mailslot "\\MAILSLOT\\BROWSE". The definition of  the
 * HostAnnouncement frame is:
 *
 *     struct {
 *         unsigned short  Opcode;
 *         unsigned char   UpdateCount;
 *         uint32_t   Periodicity;
 *         unsigned char   ServerName[];
 *         unsigned char   VersionMajor;
 *         unsigned char   VersionMinor;
 *         uint32_t   Type;
 *         uint32_t   Signature;
 *         unsigned char   Comment[];
 *     }
 *
 * where:
 *      Opcode - Identifies this structure as a browser server
 *          announcement and is defined as HostAnnouncement with a
 *          value of decimal 1.
 *
 *      UpdateCount - must be sent as zero and ignored on receipt.
 *
 *      Periodicity - The announcement frequency of the server (in
 *          seconds). The server will be removed from the browse list
 *          if it has not been heard from in 3X its announcement
 *          frequency. In no case will the server be removed from the
 *          browse list before the period 3X has elapsed. Actual
 *          implementations may take more than 3X to actually remove
 *          the server from the browse list.
 *
 *      ServerName - Null terminated ASCII server name (up to 16 bytes
 *          in length).
 *
 *      VersionMajor - The major version number of the OS the server
 *          is running. it will be returned by NetServerEnum2.
 *
 *      VersionMinor - The minor version number of the OS the server
 *          is running. This is entirely informational and does not
 *          have any significance for the browsing protocol.
 *
 *      Type - Specifies the type of the server. The server type bits
 *          are specified in the NetServerEnum2 section.
 *
 *      Signature -  The browser protocol minor version number in the
 *          low 8 bits, the browser protocol major version number in
 *          the next higher 8 bits and the signature 0xaa55 in the
 *          high 16 bits of this field. Thus, for this version of the
 *          browser protocol (1.15) this field has the value
 *          0xaa55010f. This may used to isolate browser servers that
 *          are running out of revision browser software; otherwise,
 *          it is ignored.
 *
 *      Comment - Null terminated ASCII comment for the server.
 *          Limited to 43 bytes.
 *
 * When a non-browser server starts up, it announces itself in the manner
 * described once every minute. The frequency of these statements is
 * gradually stretched to once every 12 minutes.
 *
 * Note: older non-browser servers in a domain "D" sent HostAnnouncement
 * frames to the NETBIOS group name D(00). Non-Browser servers supporting
 * version 1.15 of the browsing protocol SHOULD NOT use this NETBIOS name,
 * but for backwards compatibility Master Browsers MAY receive and process
 * HostAnnouncement frames on this name as described above for D(1d).
 */

static void
smb_browser_send_HostAnnouncement(smb_hostinfo_t *hinfo,
    uint32_t next_announcement, boolean_t remove,
    addr_entry_t *addr, char suffix)
{
        smb_msgbuf_t mb;
        int offset, announce_len, data_length;
        struct name_entry dest_name;
        unsigned char *buffer;
        uint32_t type;
        char resource_domain[SMB_PI_MAX_DOMAIN];

        if (smb_getdomainname(resource_domain, SMB_PI_MAX_DOMAIN) != 0)
                return;
        (void) smb_strupr(resource_domain);

        if (addr == NULL) {
                /* Local master Browser */
                smb_init_name_struct((unsigned char *)resource_domain, suffix,
                    0, 0, 0, 0, 0, &dest_name);
                if (smb_browser_bcast_addr_of_subnet(0, hinfo->hi_nic.nic_bcast,
                    &dest_name) < 0)
                        return;
        } else {
                smb_init_name_struct((unsigned char *)resource_domain, suffix,
                    0, 0, 0, 0, 0, &dest_name);
                dest_name.addr_list = *addr;
                dest_name.addr_list.forw = dest_name.addr_list.back =
                    &dest_name.addr_list;
        }

        /* give some extra room */
        buffer = malloc(MAX_DATAGRAM_LENGTH * 2);
        if (buffer == NULL) {
                syslog(LOG_DEBUG, "smb browser: HostAnnouncement: %m");
                return;
        }

        data_length = 1 + 1 + 4 + 16 + 1 + 1 + 4 + 4 +
            strlen(hinfo->hi_nic.nic_cmnt) + 1;

        offset = smb_browser_load_transact_header(buffer,
            MAX_DATAGRAM_LENGTH, data_length, ONE_WAY_TRANSACTION,
            MAILSLOT_BROWSE);

        if (offset < 0) {
                free(buffer);
                return;
        }

        /*
         * A non-browser server SHOULD send a HostAnnouncement browser frame
         * specifying a type of 0 just prior to shutting down, to allow it to
         * quickly be removed from the list of available servers.
         */
        if (remove || (!smb_netbios_running()))
                type = 0;
        else
                type = hinfo->hi_type;

        smb_msgbuf_init(&mb, buffer + offset, MAX_DATAGRAM_LENGTH - offset, 0);

        announce_len = smb_msgbuf_encode(&mb, "bbl16cbblls",
            HOST_ANNOUNCEMENT,
            ++hinfo->hi_updatecnt,
            next_announcement * 60000,  /* Periodicity in MilliSeconds */
            hinfo->hi_nbname,
            (uint8_t)hinfo->hi_version.sv_major,
            (uint8_t)hinfo->hi_version.sv_minor,
            type,
            SMB_SERVER_SIGNATURE,
            hinfo->hi_nic.nic_cmnt);

        if (announce_len > 0)
                (void) smb_netbios_datagram_send(&hinfo->hi_netname, &dest_name,
                    buffer, offset + announce_len);

        free(buffer);
        smb_msgbuf_term(&mb);
}

static void
smb_browser_process_AnnouncementRequest(struct datagram *datagram,
    char *mailbox)
{
        smb_hostinfo_t *hinfo;
        uint32_t next_announcement;
        uint32_t delay = random() % 29; /* in seconds */
        boolean_t h_found = B_FALSE;

        if (strcmp(mailbox, MAILSLOT_LANMAN) != 0) {
                syslog(LOG_DEBUG, "smb browser: wrong mailbox (%s)", mailbox);
                return;
        }

        smb_netbios_sleep(delay);

        (void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
        hinfo = list_head(&smb_binfo.bi_hlist);
        while (hinfo) {
                if ((hinfo->hi_nic.nic_ip.a_ipv4 &
                    hinfo->hi_nic.nic_mask) ==
                    (datagram->src.addr_list.sin.sin_addr.s_addr &
                    hinfo->hi_nic.nic_mask)) {
                        h_found = B_TRUE;
                        break;
                }
                hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
        }

        if (h_found) {
                next_announcement = hinfo->hi_nextannouce * 60 * 1000;
                smb_browser_send_HostAnnouncement(hinfo, next_announcement,
                    B_FALSE, &datagram->src.addr_list, NBT_MB);
        }
        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
}

void *
smb_browser_dispatch(void *arg)
{
        struct datagram *datagram = (struct datagram *)arg;
        smb_msgbuf_t    mb;
        int             rc;
        unsigned char   command;
        unsigned char   parameter_words;
        unsigned short  total_parameter_words;
        unsigned short  total_data_count;
        unsigned short  max_parameters_to_return;
        unsigned short  max_data_to_return;
        unsigned char   max_setup_bytes_to_return;
        unsigned short  reply;
        unsigned short  parameter_bytes_sent;
        unsigned short  parameter_offset;
        unsigned short  data_bytes_sent;
        unsigned short  data_offset;
        unsigned char   setup_word_count;
        unsigned short  setup_word_0;
        unsigned short  setup_word_1;
        unsigned short  setup_word_2;
        unsigned short  total_request_bytes;
        char            *mailbox;
        unsigned char   message_type;
        unsigned char   *data;
        int             datalen;

        syslog(LOG_DEBUG, "smb browser: packet received");

        smb_msgbuf_init(&mb, datagram->data, datagram->data_length, 0);
        rc = smb_msgbuf_decode(&mb, "Mb27.bwwwwb.w6.wwwwb.wwwws",
            &command,                   /* Command */
            &parameter_words,           /* Count of parameter words */
            &total_parameter_words,     /* Total Parameter words sent */
            &total_data_count,          /* Total Data bytes sent */
            &max_parameters_to_return,  /* Max Parameters to return */
            &max_data_to_return,        /* Max data bytes to return */
            &max_setup_bytes_to_return, /* Max setup bytes to return */
            &reply,                     /* No reply */
            &parameter_bytes_sent,      /* Parameter bytes sent */
            &parameter_offset,          /* Parameter offset */
            &data_bytes_sent,           /* Data bytes sent */
            &data_offset,               /* Data offset */
            &setup_word_count,          /* Setup word count */
            &setup_word_0,              /* Setup word[0] */
            &setup_word_1,              /* Setup word[1] */
            &setup_word_2,              /* Setup word[2] */
            &total_request_bytes,       /* Total request bytes */
            &mailbox);                  /* Mailbox address */

        if (rc < 0) {
                syslog(LOG_ERR, "smb browser: decode error");
                smb_msgbuf_term(&mb);
                free(datagram);
                return (0);
        }

        data = &datagram->data[data_offset];
        datalen = datagram->data_length - data_offset;

        /*
         * The PDC location protocol, i.e. anything on the \\NET
         * mailslot, is handled by the smb_netlogon module.
         */
        if (strncasecmp("\\MAILSLOT\\NET\\", mailbox, 14) == 0) {
                smb_netlogon_receive(datagram, mailbox, data, datalen);
                smb_msgbuf_term(&mb);
                free(datagram);
                return (0);
        }

        /*
         * If it's not a netlogon message, assume it's a browser request.
         * This is not the most elegant way to extract the command byte
         * but at least we no longer use it to get the netlogon opcode.
         */
        message_type = datagram->data[data_offset];

        switch (message_type) {
        case ANNOUNCEMENT_REQUEST :
                smb_browser_process_AnnouncementRequest(datagram, mailbox);
                break;

        default:
                syslog(LOG_DEBUG, "smb browser: invalid message type(%d, %x)",
                    message_type, message_type);
                break;
        }

        smb_msgbuf_term(&mb);
        free(datagram);
        return (0);
}


/*
 * 11.1 Registered unique names
 *
 *  <COMPUTER>(00)
 *     This name is used by all servers and clients to receive second
 *     class mailslot messages. A system must add this name in order to
 *     receive mailslot messages. The only browser requests that should
 *     appear on this name are BecomeBackup, GetBackupListResp,
 *     MasterAnnouncement, and LocalMasterAnnouncement frames. All other
 *     datagrams (other than the expected non-browser datagrams) may be
 *     ignored and an error logged.
 *
 *   <DOMAIN>(1d)
 *     This name is used to identify a master browser server for domain
 *     "DOMAIN" on a subnet.  A master browser server adds this name as a
 *     unique NETBIOS name when it becomes master browser. If the attempt
 *     to add the name fails, the master browser server assumes that there
 *     is another master in the domain and will fail to come up. It may
 *     log an error if the failure occurs more than 3 times in a row (this
 *     either indicates some form of network misconfiguration or a
 *     software error). The only requests that should appear on this name
 *     are GetBackupListRequest and HostAnnouncement requests. All other
 *     datagrams on this name may be ignored (and an error logged). If
 *     running a NETBIOS name service (NBNS, such as WINS), this name
 *     should not be registered with the NBNS.
 *
 *   <DOMAIN>(1b)
 *     This name is used to identify the Domain Master Browser for domain
 *     "DOMAIN" (which is also the primary domain controller). It is a
 *     unique name added only by the primary domain controller. The
 *     primary domain controller will respond to GetBackupListRequest on
 *     this name just as it responds to these requests on the <DOMAIN>(1d)
 *     name.
 *
 * 11.2 Registered group names
 *
 *   (01)(02)__MSBROWSE__(02)(01)
 *     This name is used by Master Browsers to announce themselves to the
 *     other Master Browsers on a subnet. It is added as a group name by
 *     all Master Browser servers. The only broadcasts that should appear
 *     on this name is DomainAnnouncement requests. All other datagrams
 *     can be ignored.
 *
 *   <DOMAIN>(00)
 *     This name is used by clients and servers in domain "DOMAIN" to
 *     process server announcements. The only requests that should appear
 *     on this name that the browser is interested in are
 *     AnnouncementRequest and NETLOGON_QUERY (to locate the PDC) packets.
 *     All other unidentifiable requests may be ignored (and an error
 *     logged).
 *
 *   <DOMAIN>(1E)
 *     This name is used for announcements to browsers for domain "DOMAIN"
 *     on a subnet. This name is registered by all the browser servers in
 *     the domain. The only requests that should appear on this name are
 *     RequestElection and AnnouncementRequest packets. All other
 *     datagrams may be ignored (and an error logged).
 *
 *   <DOMAIN>(1C)
 *     This name is registered by Primary Domain Controllers.
 */

static void
smb_browser_config(void)
{
        smb_hostinfo_t *hinfo;
        struct name_entry       name;
        struct name_entry       master;
        struct name_entry       dest;
        struct name_entry       *entry;
        char resource_domain[SMB_PI_MAX_DOMAIN];
        int rc;

        if (smb_browser_init() != 0)
                return;

        if (smb_getdomainname(resource_domain, SMB_PI_MAX_DOMAIN) != 0)
                return;
        (void) smb_strupr(resource_domain);

        /* domain<00> */
        smb_init_name_struct((unsigned char *)resource_domain, NBT_WKSTA,
            0, 0, 0, 0, 0, &name);
        entry = smb_name_find_name(&name);
        smb_name_unlock_name(entry);

        (void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
        hinfo = list_head(&smb_binfo.bi_hlist);
        while (hinfo) {
                smb_init_name_struct((unsigned char *)resource_domain,
                    NBT_WKSTA, 0, hinfo->hi_nic.nic_ip.a_ipv4,
                    htons(IPPORT_NETBIOS_DGM), NAME_ATTR_GROUP,
                    NAME_ATTR_LOCAL, &name);
                (void) smb_name_add_name(&name);

                hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
        }
        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);

        /* All our local master browsers */
        smb_init_name_struct((unsigned char *)resource_domain, NBT_MB,
            0, 0, 0, 0, 0, &dest);
        entry = smb_name_find_name(&dest);

        if (entry) {
                (void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
                hinfo = list_head(&smb_binfo.bi_hlist);
                while (hinfo) {
                        rc = smb_browser_addr_of_subnet(entry, hinfo, &master);
                        if (rc == 0) {
                                syslog(LOG_DEBUG,
                                    "smb browser: master browser found at %s",
                                    inet_ntoa(master.addr_list.sin.sin_addr));
                        }
                        hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
                }
                (void) rw_unlock(&smb_binfo.bi_hlist_rwl);

                smb_name_unlock_name(entry);
        }

        /* Domain master browser */
        smb_init_name_struct((unsigned char *)resource_domain,
            NBT_DMB, 0, 0, 0, 0, 0, &dest);

        if ((entry = smb_name_find_name(&dest)) != 0) {
                syslog(LOG_DEBUG,
                    "smb browser: domain master browser for %s is %s",
                    resource_domain,
                    inet_ntoa(entry->addr_list.sin.sin_addr));
                smb_name_unlock_name(entry);
        }
}

static int
smb_browser_init(void)
{
        smb_hostinfo_t *hinfo;
        smb_niciter_t ni;
        uint32_t type;
        smb_version_t version;

        smb_config_get_version(&version);

        (void) rw_wrlock(&smb_binfo.bi_hlist_rwl);
        smb_browser_infofree();

        if (smb_nic_getfirst(&ni) != SMB_NIC_SUCCESS) {
                (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
                return (-1);
        }

        type = MY_SERVER_TYPE;
        if (smb_config_get_secmode() == SMB_SECMODE_DOMAIN)
                type |= SV_DOMAIN_MEMBER;

        do {
                if ((ni.ni_nic.nic_smbflags & SMB_NICF_NBEXCL) ||
                    (ni.ni_nic.nic_smbflags & SMB_NICF_ALIAS))
                        continue;

                hinfo = malloc(sizeof (smb_hostinfo_t));
                if (hinfo == NULL) {
                        smb_browser_infofree();
                        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
                        return (-1);
                }

                hinfo->hi_nic = ni.ni_nic;
                /* One Minute announcements for first five */
                hinfo->hi_nextannouce = 1;
                hinfo->hi_interval = 1;
                hinfo->hi_reps = 5;
                hinfo->hi_updatecnt = 0;
                hinfo->hi_type = type;
                hinfo->hi_version = version;

                /* This is the name used for HostAnnouncement */
                (void) strlcpy(hinfo->hi_nbname, hinfo->hi_nic.nic_host,
                    NETBIOS_NAME_SZ);
                (void) smb_strupr(hinfo->hi_nbname);
                /* 0x20: file server service  */
                smb_init_name_struct((unsigned char *)hinfo->hi_nbname,
                    NBT_SERVER, 0, hinfo->hi_nic.nic_ip.a_ipv4,
                    htons(IPPORT_NETBIOS_DGM),
                    NAME_ATTR_UNIQUE, NAME_ATTR_LOCAL,
                    &hinfo->hi_netname);

                list_insert_tail(&smb_binfo.bi_hlist, hinfo);
                smb_binfo.bi_hcnt++;
        } while (smb_nic_getnext(&ni) == SMB_NIC_SUCCESS);

        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
        return (0);
}

/*
 * smb_browser_non_master_duties
 *
 * To advertise its presence, i.e. to publish itself as being available, a
 * non-browser server sends a HostAnnouncement browser frame. If the server
 * is a member of domain "D", this frame is sent to the NETBIOS unique name
 * D(1d) and mailslot "\\MAILSLOT\\BROWSE".
 */
static void
smb_browser_non_master_duties(smb_hostinfo_t *hinfo, boolean_t remove)
{
        struct name_entry name;
        struct name_entry *dest;
        addr_entry_t addr;
        char resource_domain[SMB_PI_MAX_DOMAIN];

        smb_browser_send_HostAnnouncement(hinfo, hinfo->hi_interval,
            remove, 0, NBT_MB);
        if (smb_getdomainname(resource_domain, SMB_PI_MAX_DOMAIN) != 0)
                return;

        (void) smb_strupr(resource_domain);

        smb_init_name_struct((unsigned char *)resource_domain, NBT_MB,
            0, 0, 0, 0, 0, &name);

        if ((dest = smb_name_find_name(&name))) {
                addr = dest->addr_list;
                addr.forw = addr.back = &addr;
                smb_name_unlock_name(dest);
                smb_browser_send_HostAnnouncement(hinfo, hinfo->hi_interval,
                    remove, &addr, NBT_MB);
        } else {
                smb_init_name_struct((unsigned char *)resource_domain,
                    NBT_DMB, 0, 0, 0, 0, 0, &name);
                if ((dest = smb_name_find_name(&name))) {
                        addr = dest->addr_list;
                        addr.forw = addr.back = &addr;
                        smb_name_unlock_name(dest);
                        smb_browser_send_HostAnnouncement(hinfo,
                            remove, hinfo->hi_interval, &addr, NBT_DMB);
                }
        }

        /*
         * One Minute announcements for first five
         * minutes, one minute longer each round
         * until 12 minutes and every 12 minutes
         * thereafter.
         */
        if (--hinfo->hi_reps == 0) {
                if (hinfo->hi_interval < 12)
                        hinfo->hi_interval++;

                hinfo->hi_reps = 1;
        }

        hinfo->hi_nextannouce = hinfo->hi_interval;
}


/*
 * SMB NetBIOS Browser Service
 */
/*ARGSUSED*/
void *
smb_browser_service(void *arg)
{
        smb_hostinfo_t *hinfo;

        smb_browser_infoinit();
        smb_browser_config();

        smb_netbios_event(NETBIOS_EVENT_BROWSER_START);

restart:
        do {
                (void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
                hinfo = list_head(&smb_binfo.bi_hlist);

                while (hinfo) {
                        if (--hinfo->hi_nextannouce > 0 ||
                            hinfo->hi_nic.nic_bcast == 0) {
                                hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
                                continue;
                        }

                        smb_browser_non_master_duties(hinfo, B_FALSE);

                        /* Check to see whether reconfig is needed */
                        (void) mutex_lock(&smb_binfo.bi_mtx);
                        if (smb_binfo.bi_changed) {
                                smb_binfo.bi_changed = B_FALSE;
                                (void) mutex_unlock(&smb_binfo.bi_mtx);
                                (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
                                smb_browser_config();
                                goto restart;
                        }
                        (void) mutex_unlock(&smb_binfo.bi_mtx);

                        hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
                }

                (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
                smb_netbios_sleep(SECSPERMIN);  /* 1 minute */
        } while (smb_netbios_running());

        smb_browser_infoterm();
        smb_netbios_event(NETBIOS_EVENT_BROWSER_STOP);
        return (0);
}

/*
 * smb_browser_netlogon
 *
 * Sends SAMLOGON/NETLOGON request for all host/ips, except
 * aliases, to find a domain controller.
 *
 * The dc argument will be set if a DC is found.
 */
boolean_t
smb_browser_netlogon(char *domain, char *dc, uint32_t dc_len)
{
        smb_hostinfo_t *hinfo;
        boolean_t found = B_FALSE;
        timestruc_t to;
        int err;

        (void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
        hinfo = list_head(&smb_binfo.bi_hlist);
        while (hinfo) {
                if ((hinfo->hi_nic.nic_smbflags & SMB_NICF_ALIAS) == 0)
                        smb_netlogon_request(&hinfo->hi_netname, domain);
                hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
        }
        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);

        bzero(dc, dc_len);
        to.tv_sec = 30;
        to.tv_nsec = 0;
        (void) mutex_lock(&ntdomain_mtx);
        while (ntdomain_info.n_ipaddr == 0) {
                err = cond_reltimedwait(&ntdomain_cv, &ntdomain_mtx, &to);
                if (err == ETIME)
                        break;
        }

        if (ntdomain_info.n_ipaddr != 0) {
                (void) strlcpy(dc, ntdomain_info.n_name, dc_len);
                found = B_TRUE;
        }
        (void) mutex_unlock(&ntdomain_mtx);

        return (found);
}

/*
 * smb_browser_infoinit
 *
 * This function is called only once when the browser starts
 * to initialize the global smb_binfo structure.
 */
static void
smb_browser_infoinit(void)
{
        (void) mutex_lock(&ntdomain_mtx);
        bzero(&ntdomain_info, sizeof (ntdomain_info));
        (void) mutex_unlock(&ntdomain_mtx);

        (void) rw_wrlock(&smb_binfo.bi_hlist_rwl);
        list_create(&smb_binfo.bi_hlist, sizeof (smb_hostinfo_t),
            offsetof(smb_hostinfo_t, hi_lnd));
        smb_binfo.bi_hcnt = 0;
        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);

        (void) mutex_lock(&smb_binfo.bi_mtx);
        smb_binfo.bi_changed = B_FALSE;
        (void) mutex_unlock(&smb_binfo.bi_mtx);
}

/*
 * smb_browser_infoterm
 *
 * This function is called only once when the browser stops
 * to destroy the smb_binfo structure.
 */
static void
smb_browser_infoterm(void)
{
        (void) rw_wrlock(&smb_binfo.bi_hlist_rwl);
        smb_browser_infofree();
        list_destroy(&smb_binfo.bi_hlist);
        (void) rw_unlock(&smb_binfo.bi_hlist_rwl);
}

/*
 * smb_browser_infofree
 *
 * Removes all the hostinfo structures from the browser list
 * and frees the allocated memory
 */
static void
smb_browser_infofree(void)
{
        smb_hostinfo_t *hinfo;

        while ((hinfo = list_head(&smb_binfo.bi_hlist)) != NULL) {
                list_remove(&smb_binfo.bi_hlist, hinfo);
                free(hinfo);
        }

        smb_binfo.bi_hcnt = 0;
}