xref: /titanic_51/usr/src/lib/smbsrv/libsmbns/common/smbns_browser.c (revision 7a92e70fb4f00cd79ef310c87c0daca81976ce9e)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/tzfile.h>
27 #include <errno.h>
28 #include <stdlib.h>
29 #include <stdio.h>
30 #include <unistd.h>
31 #include <syslog.h>
32 #include <string.h>
33 #include <strings.h>
34 #include <time.h>
35 #include <synch.h>
36 #include <netdb.h>
37 #include <sys/socket.h>
38 #include <arpa/inet.h>
39 
40 #include <smbsrv/libsmb.h>
41 #include <smbsrv/libsmbns.h>
42 #include <smbsrv/smb.h>
43 #include <smbsrv/mailslot.h>
44 #include <smbns_browser.h>
45 #include <smbns_netbios.h>
46 
47 /*
48  * ntdomain_info
49  * Temporary. It should be removed once NBTD is integrated.
50  */
51 smb_ntdomain_t ntdomain_info;
52 mutex_t ntdomain_mtx;
53 cond_t ntdomain_cv;
54 
55 #define	SMB_SERVER_SIGNATURE		0xaa550415
56 
57 typedef struct smb_hostinfo {
58 	list_node_t	hi_lnd;
59 	smb_nic_t	hi_nic;
60 	char		hi_nbname[NETBIOS_NAME_SZ];
61 	name_entry_t	hi_netname;
62 	uint32_t	hi_nextannouce;
63 	int		hi_reps;
64 	int		hi_interval;
65 	uint8_t		hi_updatecnt;
66 	uint32_t	hi_type;
67 	smb_version_t	hi_version;
68 } smb_hostinfo_t;
69 
70 typedef struct smb_browserinfo {
71 	list_t		bi_hlist;
72 	int		bi_hcnt;
73 	rwlock_t	bi_hlist_rwl;
74 	boolean_t	bi_changed;
75 	mutex_t		bi_mtx;
76 } smb_browserinfo_t;
77 
78 static smb_browserinfo_t smb_binfo;
79 
80 static int smb_browser_init(void);
81 static void smb_browser_infoinit(void);
82 static void smb_browser_infoterm(void);
83 static void smb_browser_infofree(void);
84 
85 
86 void
87 smb_browser_reconfig(void)
88 {
89 	(void) mutex_lock(&smb_binfo.bi_mtx);
90 	smb_binfo.bi_changed = B_TRUE;
91 	(void) mutex_unlock(&smb_binfo.bi_mtx);
92 }
93 
94 /*
95  * 3. Browser Overview
96  *
97  * Hosts involved in the browsing process can be separated into two
98  * distinct groups, browser clients and browser servers (often referred to
99  * simply as "browsers").
100  *
101  * A browser is a server which maintains information about servers -
102  * primarily the domain they are in and the services that they are running
103  * -- and about domains. Browsers may assume several different roles in
104  * their lifetimes, and dynamically switch between them.
105  *
106  *  Browser clients are of two types: workstations and (non-browser)
107  * servers. In the context of browsing, workstations query browsers for the
108  * information they contain; servers supply browsers the information by
109  * registering with them. Note that, at times, browsers may themselves
110  * behave as browser clients and query other browsers.
111  *
112  * For the purposes of this specification, a domain is simply a name with
113  * which to associate a group of resources such as computers, servers and
114  * users. Domains allow a convenient means for browser clients to restrict
115  * the scope of a search when they query browser servers. Every domain has
116  * a "master" server called the Primary Domain Controller (PDC) that
117  * manages various  activities within the domain.
118  *
119  * One browser for each domain on a subnet is designated the Local Master
120  * Browser for that domain. Servers in its domain on the subnet register
121  * with it, as do the Local Master Browsers for other domains on the
122  * subnet. It uses these registrations to maintain authoritative
123  * information about its domain on its subnet. If there are other subnets
124  * in the network, it also knows the name of the server running the
125  * domain's Domain Master Browser; it registers with it, and uses it to
126  * obtain information about the rest of the network (see below).
127  *
128  * Clients on a subnet query browsers designated as the Backup Browsers for
129  * the subnet (not the Master Browser). Backup Browsers maintain a copy of
130  * the information on the Local Master Browser; they get it by periodically
131  * querying the Local Master Browser for all of its information. Clients
132  * find the Backup Browsers by asking the Local Master Browser. Clients are
133  * expected to spread their queries evenly across Backup Browsers to
134  * balance the load.
135  *
136  * The Local Master Browser is dynamically elected automatically. Multiple
137  * Backup Browser Servers may exist per subnet; they are selected from
138  * among the potential browser servers by the Local Master Browser, which
139  * is configured to select enough to handle the expected query load.
140  *
141  * When there are multiple subnets, a Domain Master Browser is assigned
142  * the task of keeping the multiple subnets in synchronization. The Primary
143  * Domain Controller (PDC) always acts as the Domain Master Browser. The
144  * Domain Master Browser periodically acts as a client and queries all the
145  * Local Master Browsers for its domain, asking them for a list containing
146  * all the domains and all the servers in their domain known within their
147  * subnets; it merges all the replies into a single master list. This
148  * allows a Domain Master Browser server to act as a collection point for
149  * inter-subnet browsing information. Local Master Browsers periodically
150  * query the Domain Master Browser to retrieve the network-wide information
151  * it maintains.
152  *
153  * When a domain spans only a single subnet, there will not be any distinct
154  * Local Master Browser; this role will be handled by the Domain Master
155  * Browser. Similarly, the Domain Master Browser is always the Local Master
156  * Browser for the subnet it is on.
157  *
158  * When a browser client suspects that the Local Master Browser has failed,
159  * the client will instigate an election in which the browser servers
160  * participate, and some browser servers may change roles.
161  *
162  * Some characteristics of a good browsing mechanism include:
163  * . minimal network traffic
164  * . minimum server discovery time
165  * . minimum change discovery latency
166  * . immunity to machine failures
167  *
168  * Historically, Browser implementations had been very closely tied to
169  * NETBIOS and datagrams. The early implementations caused a lot of
170  * broadcast traffic. See Appendix D for an overview that presents how the
171  * Browser specification evolved.
172  *
173  * 4. Browsing Protocol Architecture
174  *
175  * This section first describes the how the browsing protocol is layered,
176  * then describes the roles of clients, servers, and browsers in the
177  * browsing subsystem.
178  *
179  * 4.1 Layering of Browsing Protocol Requests
180  *
181  * Most of the browser functionality is implemented using mailslots.
182  * Mailslots provide a mechanism for fast, unreliable unidirectional data
183  * transfer; they are named via ASCII "mailslot (path) name". Mailslots are
184  * implemented using the CIFS Transact SMB which is encapsulated in a
185  * NETBIOS datagram. Browser protocol requests are sent to browser specific
186  * mailslots using some browser-specific NETBIOS names. These datagrams can
187  * either be unicast or broadcast, depending on whether the NETBIOS name is
188  * a "unique name" or a "group name". Various data structures, which are
189  * detailed subsequently within this document, flow as the data portion of
190  * the Transact SMB.
191  *
192  * Here is an example of a generic browser SMB, showing how a browser
193  * request is encapsulated in a TRANSACT SMB request. Note that the PID,
194  * TID, MID, UID, and Flags are all 0 in mailslot requests.
195  *
196  * SMB: C transact, File = \MAILSLOT\BROWSE
197  *   SMB: SMB Status = Error Success
198  *     SMB: Error class = No Error
199  *     SMB: Error code = No Error
200  *   SMB: Header: PID = 0x0000 TID = 0x0000 MID = 0x0000 UID = 0x0000
201  *     SMB: Tree ID   (TID) = 0 (0x0)
202  *     SMB: Process ID  (PID) = 0 (0x0)
203  *     SMB: User ID   (UID) = 0 (0x0)
204  *     SMB: Multiplex ID (MID) = 0 (0x0)
205  *     SMB: Flags Summary = 0 (0x0)
206  *   SMB: Command = C transact
207  *     SMB: Word count = 17
208  *     SMB: Word parameters
209  *     SMB: Total parm bytes = 0
210  *     SMB: Total data bytes = 33
211  *     SMB: Max parm bytes = 0
212  *     SMB: Max data bytes = 0
213  *     SMB: Max setup words = 0
214  *     SMB: Transact Flags Summary = 0 (0x0)
215  *       SMB: ...............0 = Leave session intact
216  *       SMB: ..............0. = Response required
217  *     SMB: Transact timeout = 0 (0x0)
218  *     SMB: Parameter bytes = 0 (0x0)
219  *     SMB: Parameter offset = 0 (0x0)
220  *     SMB: Data bytes = 33 (0x21)
221  *     SMB: Data offset = 86 (0x56)
222  *     SMB: Setup word count = 3
223  *     SMB: Setup words
224  *     SMB: Mailslot opcode = Write mailslot
225  *     SMB: Transaction priority = 1
226  *     SMB: Mailslot class = Unreliable (broadcast)
227  *     SMB: Byte count = 50
228  *     SMB: Byte parameters
229  *     SMB: Path name = \MAILSLOT\BROWSE
230  *     SMB: Transaction data
231  *   SMB: Data: Number of data bytes remaining = 33 (0x0021)
232  *
233  * Note the SMB command is Transact, the opcode within the Transact SMB is
234  * Mailslot Write, and the browser data structure is carried as the
235  * Transact data.
236  * The Transaction data begins with an opcode, that signifies the operation
237  * and determines the size and structure of data that follows. This opcode
238  * is named as per one of the below:
239  *
240  * HostAnnouncement         1
241  * AnnouncementRequest      2
242  * RequestElection          8
243  * GetBackupListReq         9
244  * GetBackupListResp        10
245  * BecomeBackup             11
246  * DomainAnnouncment        12
247  * MasterAnnouncement       13
248  * LocalMasterAnnouncement  15
249  *
250  * Browser datagrams are often referred to as simply browser frames. The
251  * frames are in particular, referred to by the name of the opcode within
252  * the Transaction data e.g. a GetBackupListReq browser frame, a
253  * RequestElection browser frame, etc.
254  *
255  * The structures that are sent as the data portion of the Transact SMB are
256  * described in section(s) 6.2 through 6.12 in this document. These
257  * structures are tightly packed, i.e. there are no intervening pad bytes
258  * in the structure, unless they are explicitly described as being there.
259  * All quantities are sent in native Intel format and multi-byte values are
260  * transmitted least significant byte first.
261  *
262  * Besides mailslots and Transaction SMBs, the other important piece of the
263  * browser architecture is the NetServerEnum2 request. This request that
264  * allows an application to interrogate a Browser Server and obtain a
265  * complete list of resources (servers, domains, etc) known to that Browser
266  * server. Details of the NetServerEnum2 request are presented in section
267  * 6.4. Some examples of the NetServerEnum2 request being used are when a
268  * Local Master Browser sends a NetServerEnum2 request to the Domain Master
269  * Browser and vice versa. Another example is when a browser client sends a
270  * NetServerEnum2 request to a Backup Browser server.
271  *
272  * 4.3 Non-Browser Server
273  *
274  * A non-browser server is a server that has some resource(s) or service(s)
275  * it wishes to advertise as being available using the browsing protocol.
276  * Examples of non-browser servers would be an SQL server, print server,
277  * etc.
278  *
279  * A non-browser server MUST periodically send a HostAnnouncement browser
280  * frame, specifying the type of resources or services it is advertising.
281  * Details are in section 6.5.
282  *
283  * A non-browser server SHOULD announce itself relatively frequently when
284  * it first starts up in order to make its presence quickly known to the
285  * browsers and thence to potential clients. The frequency of the
286  * announcements SHOULD then be gradually stretched, so as to minimize
287  * network traffic. Typically,  non-browser servers announce themselves
288  * once every minute upon start up and then gradually adjust the frequency
289  * of the announcements to once every 12 minutes.
290  *
291  * A non-browser server SHOULD send a HostAnnouncement browser frame
292  * specifying a type of  0 just prior to shutting down, to allow it to
293  * quickly be removed from the list of available servers.
294  *
295  * A non-browser server MUST receive and process AnnouncementRequest frames
296  * from the Local Master Browser, and MUST respond with a HostAnnouncement
297  * frame, after a delay chosen randomly from the interval [0,30] seconds.
298  * AnnouncementRequests typically happen when a Local Master Browser starts
299  * up with an empty list of servers for the domain, and wants to fill it
300  * quickly. The 30 second range for responses prevents the Master Browser
301  * from becoming overloaded and losing replies, as well as preventing the
302  * network from being flooded with responses.
303  *
304  * 4.4  Browser Servers
305  *
306  * The following sections describe the roles of the various types of
307  * browser servers.
308  *
309  * 4.4.1  Potential Browser Server
310  *
311  * A Potential Browser server is a browser server that is capable of being
312  * a Backup Browser server or Master Browser server, but is not currently
313  * fulfilling either of those roles.
314  *
315  * A Potential Browser MUST set type SV_TYPE_POTENTIAL_BROWSER (see section
316  * 6.4.1) in its HostAnnouncement until it is ready to shut down. In its
317  * last HostAnnouncement frame before it shuts down, it SHOULD specify a
318  * type of  0.
319  *
320  * A Potential Browser server MUST receive and process BecomeBackup frames
321  * (see section 6.9) and become a backup browser upon their receipt.
322  *
323  * A Potential Browser MUST participate in browser elections (see section
324  * 6.8).
325  *
326  * 4.4.2  Backup Browser
327  *
328  * Backup Browser servers are a subset of the Potential Browsers that have
329  * been chosen by the Master Browser on their subnet to be the Backup
330  * Browsers for the subnet.
331  *
332  * A Backup Browser MUST set type SV_TYPE_BACKUP_BROWSER (see section
333  * 6.4.1) in its HostAnnouncement until it is ready to shut down. In its
334  * last HostAnnouncement frame before it shuts down, it SHOULD specify a
335  * type of  0.
336  *
337  * A Backup Browser MUST listen for a LocalMasterAnnouncement frame (see
338  * section 6.10) from the Local Master Browser, and use it to set the name
339  * of the Master Browser it queries for the server and domain lists.
340  *
341  * A  Backup Browsers MUST periodically make a NetServerEnum2 request of
342  * the Master Browser on its subnet for its domain to get a list of servers
343  * in that domain, as well as a list of domains. The period is a
344  * configuration option balancing currency of the information with network
345  * traffic costs - a typical value is 15 minutes.
346  *
347  * A Backup Browser SHOULD force an election by sending a RequestElection
348  * frame (see section 6.7) if it does not get a response to its periodic
349  * NetServeEnum2 request to the Master Browser.
350  *
351  * A Backup Browser MUST receive and process NetServerEnum2 requests from
352  * browser clients, for its own domain and others. If the request is for a
353  * list of servers in its domain, or for a list of domains, it can answer
354  * from its internal lists. If the request is for a list of servers in a
355  * domain different than the one it serves, it sends a NetServerEnum2
356  * request to the Domain Master Browser for that domain (which it can in
357  * find in its list of domains and their Domain Master Browsers).
358  *
359  * A Backup Browser MUST participate in browser elections (see section
360  * 6.8).
361  *
362  * 4.4.3 Master Browser
363  *
364  * Master Browsers are responsible for:
365  * . indicating it is a Master Browser
366  * . receiving server announcements and building a list of such servers
367  *   and keeping it reasonably up-to-date.
368  * . returning lists of Backup Browsers to browser clients.
369  * . ensuring an appropriate number of Backup Browsers are available.
370  * . announcing their existence to other Master Browsers on their subnet,
371  *   to the Domain Master Browser for their domain, and to all browsers in
372  *   their domain on their subnet
373  * . forwarding requests for lists of servers on other domains to the
374  *   Master Browser for that domain
375  * . keeping a list of domains in its subnet
376  * . synchronizing with the Domain Master Browser (if any) for its domain
377  * . participating in browser elections
378  * . ensuring that there is only one Master Browser on its subnet
379  *
380  * A Master Browser MUST set type SV_TYPE_MASTER_BROWSER (see section
381  * 6.4.1) in its HostAnnouncement until it is ready to shut down. In its
382  * last HostAnnouncement frame before it shuts down, it SHOULD specify a
383  * type of  0.
384  *
385  * A Master Browser MUST receive and process HostAnnouncement frames from
386  * servers, adding the server name and other information to its servers
387  * list; it must mark them as "local" entries. Periodically, it MUST check
388  * all local server entries to see if a server's HostAnnouncement has timed
389  * out (no HostAnnouncement received for three times the periodicity the
390  * server gave in the last received HostAnnouncement) and remove timed-out
391  * servers from its list.
392  *
393  * A Master Browser MUST receive and process DomainAnnouncement frames (see
394  * section 6.12) and maintain the domain names and their associated (Local)
395  * Master Browsers in its internal domain list until they time out; it must
396  * mark these as "local" entries. Periodically, it MUST check all local
397  * domain entries to see if a server's DomainAnnouncement has timed out (no
398  * DomainAnnouncement received for three times the periodicity the server
399  * gave in the last received DomainAnnouncement) and remove timed-out
400  * servers from its list.
401  *
402  * A Master Browser MUST receive and process GetBackupListRequest frames
403  * from clients, returning GetBackupListResponse frames containing a list
404  * of the Backup Servers for its domain.
405  *
406  * A Master Browser MUST eventually send BecomeBackup frames (see section
407  * 6.9) to one or more Potential Browser servers to increase the number of
408  * Backup Browsers if there are not enough Backup Browsers to handle the
409  * anticipated query load. Note: possible good times for checking for
410  * sufficient backup browsers are after being elected, when timing out
411  * server HostAnnouncements, and when receiving a server's HostAnnouncement
412  * for the first time.
413  *
414  * A Master Browser MUST periodically announce itself and the domain it
415  * serves to other (Local) Master Browsers on its subnet, by sending a
416  * DomainAnnouncement frame (see section 6.12) to its subnet.
417  *
418  * A Master Browser MUST send a MasterAnnouncement frame (see section 6.11)
419  * to the Domain Master Browser after it is first elected, and periodically
420  * thereafter. This informs the Domain Master Browser of the presence of
421  * all the Master Browsers.
422  *
423  * A Master Browser MUST periodically announce itself to all browsers for
424  * its domain on its subnet by sending a LocalMasterAnnouncement frame (see
425  * section 6.10).
426  *
427  * A Master Browser MUST receive and process NetServerEnum2 requests from
428  * browser clients, for its own domain and others. If the request is for a
429  * list of servers in its domain, or for a list of domains, it can answer
430  * from its internal lists. Entries in its list marked "local" MUST have
431  * the SV_TYPE_LOCAL_LIST_ONLY bit set in the returned results; it must be
432  * clear for all other entries. If the request is for a list of servers in
433  * a domain different than the one it serves, it sends a NetServerEnum2
434  * request to the Domain Master Browser for that domain (which it can in
435  * find in its list of domains and their Domain Master Browsers).
436  *
437  *     Note: The list of servers that the Master Browser maintains and
438  *     returns to the Backup Browsers, is limited in size to 64K of
439  *     data. This will limit the number of systems that can be in a
440  *     browse list in a single workgroup or domain to approximately two
441  *     thousand systems.
442  *
443  * A Master Browser SHOULD request all servers to register with it by
444  * sending an AnnouncementRequest frame, if, on becoming the Master Browser
445  * by winning an election, its server list is empty. Otherwise, clients
446  * might get an incomplete list of servers until the servers' periodic
447  * registrations fill the server list.
448  *
449  * If the Master Browser on a subnet is not the Primary Domain Controller
450  * (PDC), then it is a Local Master Browser.
451  *
452  * A Local Master Browser MUST periodically synchronize with the Domain
453  * Master Browser (which is the PDC). This synchronization is performed by
454  * making a NetServerEnum2 request to the Domain Master Browser and merging
455  * the results with its list of servers and domains. An entry from the
456  * Domain Master Browser should be marked "non-local", and must not
457  * overwrite an entry with the same name marked "local". The Domain Master
458  * Browser is located as specified in Appendix B.
459  *
460  * A Master Browser MUST participate in browser elections (see section
461  * 6.8).
462  *
463  * A Master Browser MUST, if it receives a HostAnnouncement,
464  * DomainAnnouncement, or LocalMasterAnnouncement frame another system that
465  * claims to be the Master Browser for its domain, demote itself from
466  * Master Browser and force an election. This ensures that there is only
467  * ever one Master Browser in each workgroup or domain.
468  *
469  * A Master Browser SHOULD, if it loses an election, become a Backup
470  * Browser (without being told to do so by the new Master Browser). Since
471  * it has more up-to-date information in its lists than a Potential
472  * Browser, it is more efficient to have it be a Backup Browser than to
473  * promote a Potential Browser.
474  *
475  * 4.4.3.1 Preferred Master Browser
476  *
477  * A Preferred Master Browser supports exactly the same protocol elements
478  * as a Potential Browser, except as follows.
479  *
480  * A Preferred Master Browser MUST always force an election when it starts
481  * up.
482  *
483  * A Preferred Master Browser MUST participate in browser elections (see
484  * section 6.8).
485  *
486  * A Preferred Master Browser MUST set the Preferred Master bit in the
487  * RequestElection frame (see section 6.7) to bias the election in its
488  * favor.
489  *
490  * A Preferred Master Browser SHOULD, if it loses an election,
491  * automatically become a Backup Browser, without being told to do so by
492  * the Master Browser.
493  *
494  * 4.4.4 Domain Master Browser
495  *
496  * Since the Domain Master Browser always runs on the PDC, it must
497  * implement all the protocols required of a PDC in addition to the
498  * browsing protocol, and that is way beyond the scope of this
499  * specification.
500  *
501  * 5. Mailslot Protocol Specification
502  *
503  * The only transaction allowed to a mailslot is a mailslot write. Mailslot
504  * writes requests are encapsulated in TRANSACT SMBs. The following table
505  * shows the interpretation of the TRANSACT SMB parameters for a mailslot
506  * transaction:
507  *
508  *  Name            Value               Description
509  *  Command         SMB_COM_TRANSACTION
510  *  Name            <name>              STRING name of mail slot to write;
511  *                                      must start with "\\MAILSLOT\\"
512  *  SetupCount      3                   Always 3 for mailslot writes
513  *  Setup[0]        1                   Command code == write mailslot
514  *  Setup[1]        Ignored
515  *  Setup[2]        Ignored
516  *  TotalDataCount  n                   Size of data in bytes to write to
517  *                                      the mailslot
518  *  Data[ n ]                           The data to write to the mailslot
519  *
520  */
521 
522 /*
523  * SMB: C transact, File = \MAILSLOT\BROWSE
524  *   SMB: SMB Status = Error Success
525  *     SMB: Error class = No Error
526  *     SMB: Error code = No Error
527  *   SMB: Header: PID = 0x0000 TID = 0x0000 MID = 0x0000 UID = 0x0000
528  *     SMB: Tree ID   (TID) = 0 (0x0)
529  *     SMB: Process ID  (PID) = 0 (0x0)
530  *     SMB: User ID   (UID) = 0 (0x0)
531  *     SMB: Multiplex ID (MID) = 0 (0x0)
532  *     SMB: Flags Summary = 0 (0x0)
533  *   SMB: Command = C transact
534  *     SMB: Word count = 17
535  *     SMB: Word parameters
536  *     SMB: Total parm bytes = 0
537  *     SMB: Total data bytes = 33
538  *     SMB: Max parm bytes = 0
539  *     SMB: Max data bytes = 0
540  *     SMB: Max setup words = 0
541  *     SMB: Transact Flags Summary = 0 (0x0)
542  *       SMB: ...............0 = Leave session intact
543  *       SMB: ..............0. = Response required
544  *     SMB: Transact timeout = 0 (0x0)
545  *     SMB: Parameter bytes = 0 (0x0)
546  *     SMB: Parameter offset = 0 (0x0)
547  *     SMB: Data bytes = 33 (0x21)
548  *     SMB: Data offset = 86 (0x56)
549  *     SMB: Setup word count = 3
550  *     SMB: Setup words
551  *     SMB: Mailslot opcode = Write mailslot
552  *     SMB: Transaction priority = 1
553  *     SMB: Mailslot class = Unreliable (broadcast)
554  *     SMB: Byte count = 50
555  *     SMB: Byte parameters
556  *     SMB: Path name = \MAILSLOT\BROWSE
557  *     SMB: Transaction data
558  *   SMB: Data: Number of data bytes remaining = 33 (0x0021)
559  *
560  * 5. Mailslot Protocol Specification
561  *
562  * The only transaction allowed to a mailslot is a mailslot write. Mailslot
563  * writes requests are encapsulated in TRANSACT SMBs. The following table
564  * shows the interpretation of the TRANSACT SMB parameters for a mailslot
565  * transaction:
566  *
567  *  Name            Value               Description
568  *  Command         SMB_COM_TRANSACTION
569  *  Name            <name>              STRING name of mail slot to write;
570  *                                      must start with "\MAILSLOT\"
571  *  SetupCount      3                   Always 3 for mailslot writes
572  *  Setup[0]        1                   Command code == write mailslot
573  *  Setup[1]        Ignored
574  *  Setup[2]        Ignored
575  *  TotalDataCount  n                   Size of data in bytes to write to
576  *                                      the mailslot
577  *  Data[ n ]                           The data to write to the mailslot
578  *
579  *	Magic		0xFF 'S' 'M' 'B'
580  *	smb_com 	a byte, the "first" command
581  *	Error		a 4-byte union, ignored in a request
582  *	smb_flg		a one byte set of eight flags
583  *	smb_flg2	a two byte set of 16 flags
584  *	.		twelve reserved bytes, have a role
585  *			in connectionless transports (IPX, UDP?)
586  *	smb_tid		a 16-bit tree ID, a mount point sorta,
587  *			0xFFFF is this command does not have
588  *			or require a tree context
589  *	smb_pid		a 16-bit process ID
590  *	smb_uid		a 16-bit user ID, specific to this "session"
591  *			and mapped to a system (bona-fide) UID
592  *	smb_mid		a 16-bit multiplex ID, used to differentiate
593  *			multiple simultaneous requests from the same
594  *			process (pid) (ref RPC "xid")
595  */
596 
597 int
598 smb_browser_load_transact_header(unsigned char *buffer, int maxcnt,
599     int data_count, int reply, char *mailbox)
600 {
601 	smb_msgbuf_t mb;
602 	int	mailboxlen;
603 	char *fmt;
604 	int result;
605 	short	class = (reply == ONE_WAY_TRANSACTION) ? 2 : 0;
606 
607 	/*
608 	 * If the mailboxlen is an even number we need to pad the
609 	 * header so that the data starts on a word boundary.
610 	 */
611 	fmt = "Mb4.bw20.bwwwwb.wl2.wwwwb.wwwws";
612 	mailboxlen = strlen(mailbox) + 1;
613 
614 	if ((mailboxlen & 0x01) == 0) {
615 		++mailboxlen;
616 		fmt = "Mb4.bw20.bwwwwb.wl2.wwwwb.wwwws.";
617 	}
618 
619 	bzero(buffer, maxcnt);
620 	smb_msgbuf_init(&mb, buffer, maxcnt, 0);
621 
622 	result = smb_msgbuf_encode(&mb, fmt,
623 	    SMB_COM_TRANSACTION,	/* Command */
624 	    0x18,
625 	    0x3,
626 	    17,				/* Count of parameter words */
627 	    0,				/* Total Parameter words sent */
628 	    data_count,			/* Total Data bytes sent */
629 	    2,				/* Max Parameters to return */
630 	    0,				/* Max data bytes to return */
631 	    0,				/* Max setup bytes to return */
632 	    reply,			/* No reply */
633 	    0xffffffff,			/* Timeout */
634 	    0,				/* Parameter bytes sent */
635 	    0,				/* Parameter offset */
636 	    data_count,			/* Data bytes sent */
637 	    69 + mailboxlen,		/* Data offset */
638 	    3,				/* Setup word count */
639 	    1,				/* Setup word[0] */
640 	    0,				/* Setup word[1] */
641 	    class,			/* Setup word[2] */
642 	    mailboxlen + data_count,	/* Total request bytes */
643 	    mailbox);			/* Mailbox address */
644 
645 	smb_msgbuf_term(&mb);
646 	return (result);
647 }
648 
649 static int
650 smb_browser_addr_of_subnet(struct name_entry *name, smb_hostinfo_t *hinfo,
651     struct name_entry *result)
652 {
653 	uint32_t ipaddr, mask, saddr;
654 	addr_entry_t *addr;
655 
656 	if (name == NULL)
657 		return (-1);
658 
659 	if (hinfo->hi_nic.nic_smbflags & SMB_NICF_ALIAS)
660 		return (-1);
661 
662 	ipaddr = hinfo->hi_nic.nic_ip.a_ipv4;
663 	mask = hinfo->hi_nic.nic_mask;
664 
665 	*result = *name;
666 	addr = &name->addr_list;
667 	do {
668 		saddr = addr->sin.sin_addr.s_addr;
669 		if ((saddr & mask) == (ipaddr & mask)) {
670 			*result = *name;
671 			result->addr_list = *addr;
672 			result->addr_list.forw = result->addr_list.back =
673 			    &result->addr_list;
674 			return (0);
675 		}
676 		addr = addr->forw;
677 	} while (addr != &name->addr_list);
678 
679 	return (-1);
680 }
681 
682 
683 static int
684 smb_browser_bcast_addr_of_subnet(struct name_entry *name, uint32_t bcast,
685     struct name_entry *result)
686 {
687 	if (name != NULL && name != result)
688 		*result = *name;
689 
690 	result->addr_list.sin.sin_family = AF_INET;
691 	result->addr_list.sinlen = sizeof (result->addr_list.sin);
692 	result->addr_list.sin.sin_addr.s_addr = bcast;
693 	result->addr_list.sin.sin_port = htons(IPPORT_NETBIOS_DGM);
694 	result->addr_list.forw = result->addr_list.back = &result->addr_list;
695 	return (0);
696 }
697 
698 /*
699  * 6.5 HostAnnouncement Browser Frame
700  *
701  * To advertise its presence, i.e. to publish itself as being available, a
702  * non-browser server sends a HostAnnouncement browser frame. If the server
703  * is a member of domain "D", this frame is sent to the NETBIOS unique name
704  * D(1d) and mailslot "\\MAILSLOT\\BROWSE". The definition of  the
705  * HostAnnouncement frame is:
706  *
707  *     struct {
708  *         unsigned short  Opcode;
709  *         unsigned char   UpdateCount;
710  *         uint32_t   Periodicity;
711  *         unsigned char   ServerName[];
712  *         unsigned char   VersionMajor;
713  *         unsigned char   VersionMinor;
714  *         uint32_t   Type;
715  *         uint32_t   Signature;
716  *         unsigned char   Comment[];
717  *     }
718  *
719  * where:
720  *      Opcode - Identifies this structure as a browser server
721  *          announcement and is defined as HostAnnouncement with a
722  *          value of decimal 1.
723  *
724  *      UpdateCount - must be sent as zero and ignored on receipt.
725  *
726  *      Periodicity - The announcement frequency of the server (in
727  *          seconds). The server will be removed from the browse list
728  *          if it has not been heard from in 3X its announcement
729  *          frequency. In no case will the server be removed from the
730  *          browse list before the period 3X has elapsed. Actual
731  *          implementations may take more than 3X to actually remove
732  *          the server from the browse list.
733  *
734  *      ServerName - Null terminated ASCII server name (up to 16 bytes
735  *          in length).
736  *
737  *      VersionMajor - The major version number of the OS the server
738  *          is running. it will be returned by NetServerEnum2.
739  *
740  *      VersionMinor - The minor version number of the OS the server
741  *          is running. This is entirely informational and does not
742  *          have any significance for the browsing protocol.
743  *
744  *      Type - Specifies the type of the server. The server type bits
745  *          are specified in the NetServerEnum2 section.
746  *
747  *      Signature -  The browser protocol minor version number in the
748  *          low 8 bits, the browser protocol major version number in
749  *          the next higher 8 bits and the signature 0xaa55 in the
750  *          high 16 bits of this field. Thus, for this version of the
751  *          browser protocol (1.15) this field has the value
752  *          0xaa55010f. This may used to isolate browser servers that
753  *          are running out of revision browser software; otherwise,
754  *          it is ignored.
755  *
756  *      Comment - Null terminated ASCII comment for the server.
757  *          Limited to 43 bytes.
758  *
759  * When a non-browser server starts up, it announces itself in the manner
760  * described once every minute. The frequency of these statements is
761  * gradually stretched to once every 12 minutes.
762  *
763  * Note: older non-browser servers in a domain "D" sent HostAnnouncement
764  * frames to the NETBIOS group name D(00). Non-Browser servers supporting
765  * version 1.15 of the browsing protocol SHOULD NOT use this NETBIOS name,
766  * but for backwards compatibility Master Browsers MAY receive and process
767  * HostAnnouncement frames on this name as described above for D(1d).
768  */
769 
770 static void
771 smb_browser_send_HostAnnouncement(smb_hostinfo_t *hinfo,
772     uint32_t next_announcement, boolean_t remove,
773     addr_entry_t *addr, char suffix)
774 {
775 	smb_msgbuf_t mb;
776 	int offset, announce_len, data_length;
777 	struct name_entry dest_name;
778 	unsigned char *buffer;
779 	uint32_t type;
780 	char resource_domain[SMB_PI_MAX_DOMAIN];
781 
782 	if (smb_getdomainname(resource_domain, SMB_PI_MAX_DOMAIN) != 0)
783 		return;
784 	(void) smb_strupr(resource_domain);
785 
786 	if (addr == NULL) {
787 		/* Local master Browser */
788 		smb_init_name_struct((unsigned char *)resource_domain, suffix,
789 		    0, 0, 0, 0, 0, &dest_name);
790 		if (smb_browser_bcast_addr_of_subnet(0, hinfo->hi_nic.nic_bcast,
791 		    &dest_name) < 0)
792 			return;
793 	} else {
794 		smb_init_name_struct((unsigned char *)resource_domain, suffix,
795 		    0, 0, 0, 0, 0, &dest_name);
796 		dest_name.addr_list = *addr;
797 		dest_name.addr_list.forw = dest_name.addr_list.back =
798 		    &dest_name.addr_list;
799 	}
800 
801 	/* give some extra room */
802 	buffer = malloc(MAX_DATAGRAM_LENGTH * 2);
803 	if (buffer == NULL) {
804 		syslog(LOG_DEBUG, "smb browser: HostAnnouncement: %m");
805 		return;
806 	}
807 
808 	data_length = 1 + 1 + 4 + 16 + 1 + 1 + 4 + 4 +
809 	    strlen(hinfo->hi_nic.nic_cmnt) + 1;
810 
811 	offset = smb_browser_load_transact_header(buffer,
812 	    MAX_DATAGRAM_LENGTH, data_length, ONE_WAY_TRANSACTION,
813 	    MAILSLOT_BROWSE);
814 
815 	if (offset < 0) {
816 		free(buffer);
817 		return;
818 	}
819 
820 	/*
821 	 * A non-browser server SHOULD send a HostAnnouncement browser frame
822 	 * specifying a type of 0 just prior to shutting down, to allow it to
823 	 * quickly be removed from the list of available servers.
824 	 */
825 	if (remove || (!smb_netbios_running()))
826 		type = 0;
827 	else
828 		type = hinfo->hi_type;
829 
830 	smb_msgbuf_init(&mb, buffer + offset, MAX_DATAGRAM_LENGTH - offset, 0);
831 
832 	announce_len = smb_msgbuf_encode(&mb, "bbl16cbblls",
833 	    HOST_ANNOUNCEMENT,
834 	    ++hinfo->hi_updatecnt,
835 	    next_announcement * 60000,	/* Periodicity in MilliSeconds */
836 	    hinfo->hi_nbname,
837 	    hinfo->hi_version.sv_major,
838 	    hinfo->hi_version.sv_minor,
839 	    type,
840 	    SMB_SERVER_SIGNATURE,
841 	    hinfo->hi_nic.nic_cmnt);
842 
843 	if (announce_len > 0)
844 		(void) smb_netbios_datagram_send(&hinfo->hi_netname, &dest_name,
845 		    buffer, offset + announce_len);
846 
847 	free(buffer);
848 	smb_msgbuf_term(&mb);
849 }
850 
851 static void
852 smb_browser_process_AnnouncementRequest(struct datagram *datagram,
853     char *mailbox)
854 {
855 	smb_hostinfo_t *hinfo;
856 	uint32_t next_announcement;
857 	uint32_t delay = random() % 29; /* in seconds */
858 	boolean_t h_found = B_FALSE;
859 
860 	if (strcmp(mailbox, MAILSLOT_LANMAN) != 0) {
861 		syslog(LOG_DEBUG, "smb browser: wrong mailbox (%s)", mailbox);
862 		return;
863 	}
864 
865 	smb_netbios_sleep(delay);
866 
867 	(void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
868 	hinfo = list_head(&smb_binfo.bi_hlist);
869 	while (hinfo) {
870 		if ((hinfo->hi_nic.nic_ip.a_ipv4 &
871 		    hinfo->hi_nic.nic_mask) ==
872 		    (datagram->src.addr_list.sin.sin_addr.s_addr &
873 		    hinfo->hi_nic.nic_mask)) {
874 			h_found = B_TRUE;
875 			break;
876 		}
877 		hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
878 	}
879 
880 	if (h_found) {
881 		next_announcement = hinfo->hi_nextannouce * 60 * 1000;
882 		smb_browser_send_HostAnnouncement(hinfo, next_announcement,
883 		    B_FALSE, &datagram->src.addr_list, NBT_MB);
884 	}
885 	(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
886 }
887 
888 void *
889 smb_browser_dispatch(void *arg)
890 {
891 	struct datagram *datagram = (struct datagram *)arg;
892 	smb_msgbuf_t 	mb;
893 	int		rc;
894 	unsigned char	command;
895 	unsigned char	parameter_words;
896 	unsigned short	total_parameter_words;
897 	unsigned short	total_data_count;
898 	unsigned short	max_parameters_to_return;
899 	unsigned short	max_data_to_return;
900 	unsigned char	max_setup_bytes_to_return;
901 	unsigned short	reply;
902 	unsigned short	parameter_bytes_sent;
903 	unsigned short	parameter_offset;
904 	unsigned short	data_bytes_sent;
905 	unsigned short	data_offset;
906 	unsigned char	setup_word_count;
907 	unsigned short	setup_word_0;
908 	unsigned short	setup_word_1;
909 	unsigned short	setup_word_2;
910 	unsigned short	total_request_bytes;
911 	char 		*mailbox;
912 	unsigned char	message_type;
913 	unsigned char 	*data;
914 	int		datalen;
915 
916 	syslog(LOG_DEBUG, "smb browser: packet received");
917 
918 	smb_msgbuf_init(&mb, datagram->data, datagram->data_length, 0);
919 	rc = smb_msgbuf_decode(&mb, "Mb27.bwwwwb.w6.wwwwb.wwwws",
920 	    &command,			/* Command */
921 	    &parameter_words,		/* Count of parameter words */
922 	    &total_parameter_words,	/* Total Parameter words sent */
923 	    &total_data_count,		/* Total Data bytes sent */
924 	    &max_parameters_to_return,	/* Max Parameters to return */
925 	    &max_data_to_return,	/* Max data bytes to return */
926 	    &max_setup_bytes_to_return,	/* Max setup bytes to return */
927 	    &reply,			/* No reply */
928 	    &parameter_bytes_sent,	/* Parameter bytes sent */
929 	    &parameter_offset,		/* Parameter offset */
930 	    &data_bytes_sent,		/* Data bytes sent */
931 	    &data_offset,		/* Data offset */
932 	    &setup_word_count,		/* Setup word count */
933 	    &setup_word_0,		/* Setup word[0] */
934 	    &setup_word_1,		/* Setup word[1] */
935 	    &setup_word_2,		/* Setup word[2] */
936 	    &total_request_bytes,	/* Total request bytes */
937 	    &mailbox);			/* Mailbox address */
938 
939 	if (rc < 0) {
940 		syslog(LOG_ERR, "smb browser: decode error");
941 		smb_msgbuf_term(&mb);
942 		free(datagram);
943 		return (0);
944 	}
945 
946 	data = &datagram->data[data_offset];
947 	datalen = datagram->data_length - data_offset;
948 
949 	/*
950 	 * The PDC location protocol, i.e. anything on the \\NET
951 	 * mailslot, is handled by the smb_netlogon module.
952 	 */
953 	if (strncasecmp("\\MAILSLOT\\NET\\", mailbox, 14) == 0) {
954 		smb_netlogon_receive(datagram, mailbox, data, datalen);
955 		smb_msgbuf_term(&mb);
956 		free(datagram);
957 		return (0);
958 	}
959 
960 	/*
961 	 * If it's not a netlogon message, assume it's a browser request.
962 	 * This is not the most elegant way to extract the command byte
963 	 * but at least we no longer use it to get the netlogon opcode.
964 	 */
965 	message_type = datagram->data[data_offset];
966 
967 	switch (message_type) {
968 	case ANNOUNCEMENT_REQUEST :
969 		smb_browser_process_AnnouncementRequest(datagram, mailbox);
970 		break;
971 
972 	default:
973 		syslog(LOG_DEBUG, "smb browser: invalid message type(%d, %x)",
974 		    message_type, message_type);
975 		break;
976 	}
977 
978 	smb_msgbuf_term(&mb);
979 	free(datagram);
980 	return (0);
981 }
982 
983 
984 /*
985  * 11.1 Registered unique names
986  *
987  *  <COMPUTER>(00)
988  *     This name is used by all servers and clients to receive second
989  *     class mailslot messages. A system must add this name in order to
990  *     receive mailslot messages. The only browser requests that should
991  *     appear on this name are BecomeBackup, GetBackupListResp,
992  *     MasterAnnouncement, and LocalMasterAnnouncement frames. All other
993  *     datagrams (other than the expected non-browser datagrams) may be
994  *     ignored and an error logged.
995  *
996  *   <DOMAIN>(1d)
997  *     This name is used to identify a master browser server for domain
998  *     "DOMAIN" on a subnet.  A master browser server adds this name as a
999  *     unique NETBIOS name when it becomes master browser. If the attempt
1000  *     to add the name fails, the master browser server assumes that there
1001  *     is another master in the domain and will fail to come up. It may
1002  *     log an error if the failure occurs more than 3 times in a row (this
1003  *     either indicates some form of network misconfiguration or a
1004  *     software error). The only requests that should appear on this name
1005  *     are GetBackupListRequest and HostAnnouncement requests. All other
1006  *     datagrams on this name may be ignored (and an error logged). If
1007  *     running a NETBIOS name service (NBNS, such as WINS), this name
1008  *     should not be registered with the NBNS.
1009  *
1010  *   <DOMAIN>(1b)
1011  *     This name is used to identify the Domain Master Browser for domain
1012  *     "DOMAIN" (which is also the primary domain controller). It is a
1013  *     unique name added only by the primary domain controller. The
1014  *     primary domain controller will respond to GetBackupListRequest on
1015  *     this name just as it responds to these requests on the <DOMAIN>(1d)
1016  *     name.
1017  *
1018  * 11.2 Registered group names
1019  *
1020  *   (01)(02)__MSBROWSE__(02)(01)
1021  *     This name is used by Master Browsers to announce themselves to the
1022  *     other Master Browsers on a subnet. It is added as a group name by
1023  *     all Master Browser servers. The only broadcasts that should appear
1024  *     on this name is DomainAnnouncement requests. All other datagrams
1025  *     can be ignored.
1026  *
1027  *   <DOMAIN>(00)
1028  *     This name is used by clients and servers in domain "DOMAIN" to
1029  *     process server announcements. The only requests that should appear
1030  *     on this name that the browser is interested in are
1031  *     AnnouncementRequest and NETLOGON_QUERY (to locate the PDC) packets.
1032  *     All other unidentifiable requests may be ignored (and an error
1033  *     logged).
1034  *
1035  *   <DOMAIN>(1E)
1036  *     This name is used for announcements to browsers for domain "DOMAIN"
1037  *     on a subnet. This name is registered by all the browser servers in
1038  *     the domain. The only requests that should appear on this name are
1039  *     RequestElection and AnnouncementRequest packets. All other
1040  *     datagrams may be ignored (and an error logged).
1041  *
1042  *   <DOMAIN>(1C)
1043  *     This name is registered by Primary Domain Controllers.
1044  */
1045 
1046 static void
1047 smb_browser_config(void)
1048 {
1049 	smb_hostinfo_t *hinfo;
1050 	struct name_entry	name;
1051 	struct name_entry	master;
1052 	struct name_entry	dest;
1053 	struct name_entry	*entry;
1054 	char resource_domain[SMB_PI_MAX_DOMAIN];
1055 	int rc;
1056 
1057 	if (smb_browser_init() != 0)
1058 		return;
1059 
1060 	if (smb_getdomainname(resource_domain, SMB_PI_MAX_DOMAIN) != 0)
1061 		return;
1062 	(void) smb_strupr(resource_domain);
1063 
1064 	/* domain<00> */
1065 	smb_init_name_struct((unsigned char *)resource_domain, NBT_WKSTA,
1066 	    0, 0, 0, 0, 0, &name);
1067 	entry = smb_name_find_name(&name);
1068 	smb_name_unlock_name(entry);
1069 
1070 	(void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
1071 	hinfo = list_head(&smb_binfo.bi_hlist);
1072 	while (hinfo) {
1073 		smb_init_name_struct((unsigned char *)resource_domain,
1074 		    NBT_WKSTA, 0, hinfo->hi_nic.nic_ip.a_ipv4,
1075 		    htons(IPPORT_NETBIOS_DGM), NAME_ATTR_GROUP,
1076 		    NAME_ATTR_LOCAL, &name);
1077 		(void) smb_name_add_name(&name);
1078 
1079 		hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
1080 	}
1081 	(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1082 
1083 	/* All our local master browsers */
1084 	smb_init_name_struct((unsigned char *)resource_domain, NBT_MB,
1085 	    0, 0, 0, 0, 0, &dest);
1086 	entry = smb_name_find_name(&dest);
1087 
1088 	if (entry) {
1089 		(void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
1090 		hinfo = list_head(&smb_binfo.bi_hlist);
1091 		while (hinfo) {
1092 			rc = smb_browser_addr_of_subnet(entry, hinfo, &master);
1093 			if (rc == 0) {
1094 				syslog(LOG_DEBUG,
1095 				    "smb browser: master browser found at %s",
1096 				    inet_ntoa(master.addr_list.sin.sin_addr));
1097 			}
1098 			hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
1099 		}
1100 		(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1101 
1102 		smb_name_unlock_name(entry);
1103 	}
1104 
1105 	/* Domain master browser */
1106 	smb_init_name_struct((unsigned char *)resource_domain,
1107 	    NBT_DMB, 0, 0, 0, 0, 0, &dest);
1108 
1109 	if ((entry = smb_name_find_name(&dest)) != 0) {
1110 		syslog(LOG_DEBUG,
1111 		    "smb browser: domain master browser for %s is %s",
1112 		    resource_domain,
1113 		    inet_ntoa(entry->addr_list.sin.sin_addr));
1114 		smb_name_unlock_name(entry);
1115 	}
1116 }
1117 
1118 static int
1119 smb_browser_init(void)
1120 {
1121 	smb_hostinfo_t *hinfo;
1122 	smb_niciter_t ni;
1123 	uint32_t type;
1124 	smb_version_t version;
1125 
1126 	smb_config_get_version(&version);
1127 
1128 	(void) rw_wrlock(&smb_binfo.bi_hlist_rwl);
1129 	smb_browser_infofree();
1130 
1131 	if (smb_nic_getfirst(&ni) != SMB_NIC_SUCCESS) {
1132 		(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1133 		return (-1);
1134 	}
1135 
1136 	type = MY_SERVER_TYPE;
1137 	if (smb_config_get_secmode() == SMB_SECMODE_DOMAIN)
1138 		type |= SV_DOMAIN_MEMBER;
1139 
1140 	do {
1141 		if ((ni.ni_nic.nic_smbflags & SMB_NICF_NBEXCL) ||
1142 		    (ni.ni_nic.nic_smbflags & SMB_NICF_ALIAS))
1143 			continue;
1144 
1145 		hinfo = malloc(sizeof (smb_hostinfo_t));
1146 		if (hinfo == NULL) {
1147 			smb_browser_infofree();
1148 			(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1149 			return (-1);
1150 		}
1151 
1152 		hinfo->hi_nic = ni.ni_nic;
1153 		/* One Minute announcements for first five */
1154 		hinfo->hi_nextannouce = 1;
1155 		hinfo->hi_interval = 1;
1156 		hinfo->hi_reps = 5;
1157 		hinfo->hi_updatecnt = 0;
1158 		hinfo->hi_type = type;
1159 		hinfo->hi_version = version;
1160 
1161 		/* This is the name used for HostAnnouncement */
1162 		(void) strlcpy(hinfo->hi_nbname, hinfo->hi_nic.nic_host,
1163 		    NETBIOS_NAME_SZ);
1164 		(void) smb_strupr(hinfo->hi_nbname);
1165 		/* 0x20: file server service  */
1166 		smb_init_name_struct((unsigned char *)hinfo->hi_nbname,
1167 		    NBT_SERVER, 0, hinfo->hi_nic.nic_ip.a_ipv4,
1168 		    htons(IPPORT_NETBIOS_DGM),
1169 		    NAME_ATTR_UNIQUE, NAME_ATTR_LOCAL,
1170 		    &hinfo->hi_netname);
1171 
1172 		list_insert_tail(&smb_binfo.bi_hlist, hinfo);
1173 		smb_binfo.bi_hcnt++;
1174 	} while (smb_nic_getnext(&ni) == SMB_NIC_SUCCESS);
1175 
1176 	(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1177 	return (0);
1178 }
1179 
1180 /*
1181  * smb_browser_non_master_duties
1182  *
1183  * To advertise its presence, i.e. to publish itself as being available, a
1184  * non-browser server sends a HostAnnouncement browser frame. If the server
1185  * is a member of domain "D", this frame is sent to the NETBIOS unique name
1186  * D(1d) and mailslot "\\MAILSLOT\\BROWSE".
1187  */
1188 static void
1189 smb_browser_non_master_duties(smb_hostinfo_t *hinfo, boolean_t remove)
1190 {
1191 	struct name_entry name;
1192 	struct name_entry *dest;
1193 	addr_entry_t addr;
1194 	char resource_domain[SMB_PI_MAX_DOMAIN];
1195 
1196 	smb_browser_send_HostAnnouncement(hinfo, hinfo->hi_interval,
1197 	    remove, 0, NBT_MB);
1198 	if (smb_getdomainname(resource_domain, SMB_PI_MAX_DOMAIN) != 0)
1199 		return;
1200 
1201 	(void) smb_strupr(resource_domain);
1202 
1203 	smb_init_name_struct((unsigned char *)resource_domain, NBT_MB,
1204 	    0, 0, 0, 0, 0, &name);
1205 
1206 	if ((dest = smb_name_find_name(&name))) {
1207 		addr = dest->addr_list;
1208 		addr.forw = addr.back = &addr;
1209 		smb_name_unlock_name(dest);
1210 		smb_browser_send_HostAnnouncement(hinfo, hinfo->hi_interval,
1211 		    remove, &addr, NBT_MB);
1212 	} else {
1213 		smb_init_name_struct((unsigned char *)resource_domain,
1214 		    NBT_DMB, 0, 0, 0, 0, 0, &name);
1215 		if ((dest = smb_name_find_name(&name))) {
1216 			addr = dest->addr_list;
1217 			addr.forw = addr.back = &addr;
1218 			smb_name_unlock_name(dest);
1219 			smb_browser_send_HostAnnouncement(hinfo,
1220 			    remove, hinfo->hi_interval, &addr, NBT_DMB);
1221 		}
1222 	}
1223 
1224 	/*
1225 	 * One Minute announcements for first five
1226 	 * minutes, one minute longer each round
1227 	 * until 12 minutes and every 12 minutes
1228 	 * thereafter.
1229 	 */
1230 	if (--hinfo->hi_reps == 0) {
1231 		if (hinfo->hi_interval < 12)
1232 			hinfo->hi_interval++;
1233 
1234 		hinfo->hi_reps = 1;
1235 	}
1236 
1237 	hinfo->hi_nextannouce = hinfo->hi_interval;
1238 }
1239 
1240 
1241 /*
1242  * SMB NetBIOS Browser Service
1243  */
1244 /*ARGSUSED*/
1245 void *
1246 smb_browser_service(void *arg)
1247 {
1248 	smb_hostinfo_t *hinfo;
1249 
1250 	smb_browser_infoinit();
1251 	smb_browser_config();
1252 
1253 	smb_netbios_event(NETBIOS_EVENT_BROWSER_START);
1254 
1255 restart:
1256 	do {
1257 		(void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
1258 		hinfo = list_head(&smb_binfo.bi_hlist);
1259 
1260 		while (hinfo) {
1261 			if (--hinfo->hi_nextannouce > 0 ||
1262 			    hinfo->hi_nic.nic_bcast == 0) {
1263 				hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
1264 				continue;
1265 			}
1266 
1267 			smb_browser_non_master_duties(hinfo, B_FALSE);
1268 
1269 			/* Check to see whether reconfig is needed */
1270 			(void) mutex_lock(&smb_binfo.bi_mtx);
1271 			if (smb_binfo.bi_changed) {
1272 				smb_binfo.bi_changed = B_FALSE;
1273 				(void) mutex_unlock(&smb_binfo.bi_mtx);
1274 				(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1275 				smb_browser_config();
1276 				goto restart;
1277 			}
1278 			(void) mutex_unlock(&smb_binfo.bi_mtx);
1279 
1280 			hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
1281 		}
1282 
1283 		(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1284 		smb_netbios_sleep(SECSPERMIN);	/* 1 minute */
1285 	} while (smb_netbios_running());
1286 
1287 	smb_browser_infoterm();
1288 	smb_netbios_event(NETBIOS_EVENT_BROWSER_STOP);
1289 	return (0);
1290 }
1291 
1292 /*
1293  * smb_browser_netlogon
1294  *
1295  * Sends SAMLOGON/NETLOGON request for all host/ips, except
1296  * aliases, to find a domain controller.
1297  *
1298  * The dc argument will be set if a DC is found.
1299  */
1300 boolean_t
1301 smb_browser_netlogon(char *domain, char *dc, uint32_t dc_len)
1302 {
1303 	smb_hostinfo_t *hinfo;
1304 	boolean_t found = B_FALSE;
1305 	timestruc_t to;
1306 	int err;
1307 
1308 	(void) rw_rdlock(&smb_binfo.bi_hlist_rwl);
1309 	hinfo = list_head(&smb_binfo.bi_hlist);
1310 	while (hinfo) {
1311 		if ((hinfo->hi_nic.nic_smbflags & SMB_NICF_ALIAS) == 0)
1312 			smb_netlogon_request(&hinfo->hi_netname, domain);
1313 		hinfo = list_next(&smb_binfo.bi_hlist, hinfo);
1314 	}
1315 	(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1316 
1317 	bzero(dc, dc_len);
1318 	to.tv_sec = 30;
1319 	to.tv_nsec = 0;
1320 	(void) mutex_lock(&ntdomain_mtx);
1321 	while (ntdomain_info.n_ipaddr == 0) {
1322 		err = cond_reltimedwait(&ntdomain_cv, &ntdomain_mtx, &to);
1323 		if (err == ETIME)
1324 			break;
1325 	}
1326 
1327 	if (ntdomain_info.n_ipaddr != 0) {
1328 		(void) strlcpy(dc, ntdomain_info.n_name, dc_len);
1329 		found = B_TRUE;
1330 	}
1331 	(void) mutex_unlock(&ntdomain_mtx);
1332 
1333 	return (found);
1334 }
1335 
1336 /*
1337  * smb_browser_infoinit
1338  *
1339  * This function is called only once when the browser starts
1340  * to initialize the global smb_binfo structure.
1341  */
1342 static void
1343 smb_browser_infoinit(void)
1344 {
1345 	(void) mutex_lock(&ntdomain_mtx);
1346 	bzero(&ntdomain_info, sizeof (ntdomain_info));
1347 	(void) mutex_unlock(&ntdomain_mtx);
1348 
1349 	(void) rw_wrlock(&smb_binfo.bi_hlist_rwl);
1350 	list_create(&smb_binfo.bi_hlist, sizeof (smb_hostinfo_t),
1351 	    offsetof(smb_hostinfo_t, hi_lnd));
1352 	smb_binfo.bi_hcnt = 0;
1353 	(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1354 
1355 	(void) mutex_lock(&smb_binfo.bi_mtx);
1356 	smb_binfo.bi_changed = B_FALSE;
1357 	(void) mutex_unlock(&smb_binfo.bi_mtx);
1358 }
1359 
1360 /*
1361  * smb_browser_infoterm
1362  *
1363  * This function is called only once when the browser stops
1364  * to destroy the smb_binfo structure.
1365  */
1366 static void
1367 smb_browser_infoterm(void)
1368 {
1369 	(void) rw_wrlock(&smb_binfo.bi_hlist_rwl);
1370 	smb_browser_infofree();
1371 	list_destroy(&smb_binfo.bi_hlist);
1372 	(void) rw_unlock(&smb_binfo.bi_hlist_rwl);
1373 }
1374 
1375 /*
1376  * smb_browser_infofree
1377  *
1378  * Removes all the hostinfo structures from the browser list
1379  * and frees the allocated memory
1380  */
1381 static void
1382 smb_browser_infofree(void)
1383 {
1384 	smb_hostinfo_t *hinfo;
1385 
1386 	while ((hinfo = list_head(&smb_binfo.bi_hlist)) != NULL) {
1387 		list_remove(&smb_binfo.bi_hlist, hinfo);
1388 		free(hinfo);
1389 	}
1390 
1391 	smb_binfo.bi_hcnt = 0;
1392 }
1393