s3: Fix uninitialized memory read in talloc_free()
[Samba.git] / source3 / nmbd / nmbd_elections.c
bloba7b240f05e3c2d12dc7c2aa922336c6a52eed311
1 /*
2 Unix SMB/CIFS implementation.
3 NBT netbios routines and daemon - version 2
4 Copyright (C) Andrew Tridgell 1994-1998
5 Copyright (C) Luke Kenneth Casson Leighton 1994-1998
6 Copyright (C) Jeremy Allison 1994-2003
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include "includes.h"
24 #include "nmbd/nmbd.h"
25 #include "smbprofile.h"
27 /* Election parameters. */
28 extern time_t StartupTime;
30 /****************************************************************************
31 Send an election datagram packet.
32 **************************************************************************/
34 static void send_election_dgram(struct subnet_record *subrec, const char *workgroup_name,
35 uint32 criterion, int timeup,const char *server_name)
37 char outbuf[1024];
38 unstring srv_name;
39 char *p;
41 DEBUG(2,("send_election_dgram: Sending election packet for workgroup %s on subnet %s\n",
42 workgroup_name, subrec->subnet_name ));
44 memset(outbuf,'\0',sizeof(outbuf));
45 p = outbuf;
46 SCVAL(p,0,ANN_Election); /* Election opcode. */
47 p++;
49 SCVAL(p,0,((criterion == 0 && timeup == 0) ? 0 : ELECTION_VERSION));
50 SIVAL(p,1,criterion);
51 SIVAL(p,5,timeup*1000); /* ms - Despite what the spec says. */
52 p += 13;
53 unstrcpy(srv_name, server_name);
54 strupper_m(srv_name);
55 /* The following call does UNIX -> DOS charset conversion. */
56 push_ascii(p, srv_name, sizeof(outbuf)-PTR_DIFF(p,outbuf)-1, STR_TERMINATE);
57 p = skip_string(outbuf,sizeof(outbuf),p);
59 send_mailslot(False, BROWSE_MAILSLOT, outbuf, PTR_DIFF(p,outbuf),
60 global_myname(), 0,
61 workgroup_name, 0x1e,
62 subrec->bcast_ip, subrec->myip, DGRAM_PORT);
65 /*******************************************************************
66 We found a current master browser on one of our broadcast interfaces.
67 ******************************************************************/
69 static void check_for_master_browser_success(struct subnet_record *subrec,
70 struct userdata_struct *userdata,
71 struct nmb_name *answer_name,
72 struct in_addr answer_ip, struct res_rec *rrec)
74 unstring aname;
75 pull_ascii_nstring(aname, sizeof(aname), answer_name->name);
76 DEBUG(3,("check_for_master_browser_success: Local master browser for workgroup %s exists at \
77 IP %s (just checking).\n", aname, inet_ntoa(answer_ip) ));
80 /*******************************************************************
81 We failed to find a current master browser on one of our broadcast interfaces.
82 ******************************************************************/
84 static void check_for_master_browser_fail( struct subnet_record *subrec,
85 struct response_record *rrec,
86 struct nmb_name *question_name,
87 int fail_code)
89 unstring workgroup_name;
90 struct work_record *work;
92 pull_ascii_nstring(workgroup_name,sizeof(workgroup_name),question_name->name);
94 work = find_workgroup_on_subnet(subrec, workgroup_name);
95 if(work == NULL) {
96 DEBUG(0,("check_for_master_browser_fail: Unable to find workgroup %s on subnet %s.=\n",
97 workgroup_name, subrec->subnet_name ));
98 return;
101 if (strequal(work->work_group, lp_workgroup())) {
103 if (lp_local_master()) {
104 /* We have discovered that there is no local master
105 browser, and we are configured to initiate
106 an election that we will participate in.
108 DEBUG(2,("check_for_master_browser_fail: Forcing election on workgroup %s subnet %s\n",
109 work->work_group, subrec->subnet_name ));
111 /* Setting this means we will participate when the
112 election is run in run_elections(). */
113 work->needelection = True;
114 } else {
115 /* We need to force an election, because we are configured
116 not to become the local master, but we still need one,
117 having detected that one doesn't exist.
119 send_election_dgram(subrec, work->work_group, 0, 0, "");
124 /*******************************************************************
125 Ensure there is a local master browser for a workgroup on our
126 broadcast interfaces.
127 ******************************************************************/
129 void check_master_browser_exists(time_t t)
131 static time_t lastrun=0;
132 struct subnet_record *subrec;
133 const char *workgroup_name = lp_workgroup();
135 if (t < (lastrun + (CHECK_TIME_MST_BROWSE * 60)))
136 return;
138 lastrun = t;
140 dump_workgroups(False);
142 for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
143 struct work_record *work;
145 for (work = subrec->workgrouplist; work; work = work->next) {
146 if (strequal(work->work_group, workgroup_name) && !AM_LOCAL_MASTER_BROWSER(work)) {
147 /* Do a name query for the local master browser on this net. */
148 query_name( subrec, work->work_group, 0x1d,
149 check_for_master_browser_success,
150 check_for_master_browser_fail,
151 NULL);
157 /*******************************************************************
158 Run an election.
159 ******************************************************************/
161 void run_elections(time_t t)
163 static time_t lastime = 0;
165 struct subnet_record *subrec;
167 START_PROFILE(run_elections);
169 /* Send election packets once every 2 seconds - note */
170 if (lastime && (t - lastime < 2)) {
171 END_PROFILE(run_elections);
172 return;
175 lastime = t;
177 for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
178 struct work_record *work;
180 for (work = subrec->workgrouplist; work; work = work->next) {
181 if (work->RunningElection) {
183 * We can only run an election for a workgroup if we have
184 * registered the WORKGROUP<1e> name, as that's the name
185 * we must listen to.
187 struct nmb_name nmbname;
189 make_nmb_name(&nmbname, work->work_group, 0x1e);
190 if(find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME)==NULL) {
191 DEBUG(8,("run_elections: Cannot send election packet yet as name %s not \
192 yet registered on subnet %s\n", nmb_namestr(&nmbname), subrec->subnet_name ));
193 continue;
196 send_election_dgram(subrec, work->work_group, work->ElectionCriterion,
197 t - StartupTime, global_myname());
199 if (work->ElectionCount++ >= 4) {
200 /* Won election (4 packets were sent out uncontested. */
201 DEBUG(2,("run_elections: >>> Won election for workgroup %s on subnet %s <<<\n",
202 work->work_group, subrec->subnet_name ));
204 work->RunningElection = False;
206 become_local_master_browser(subrec, work);
211 END_PROFILE(run_elections);
214 /*******************************************************************
215 Determine if I win an election.
216 ******************************************************************/
218 static bool win_election(struct work_record *work, int version,
219 uint32 criterion, int timeup, const char *server_name)
221 int mytimeup = time(NULL) - StartupTime;
222 uint32 mycriterion = work->ElectionCriterion;
224 /* If local master is false then never win in election broadcasts. */
225 if(!lp_local_master()) {
226 DEBUG(3,("win_election: Losing election as local master == False\n"));
227 return False;
230 DEBUG(4,("win_election: election comparison: %x:%x %x:%x %d:%d %s:%s\n",
231 version, ELECTION_VERSION,
232 criterion, mycriterion,
233 timeup, mytimeup,
234 server_name, global_myname()));
236 if (version > ELECTION_VERSION)
237 return(False);
238 if (version < ELECTION_VERSION)
239 return(True);
241 if (criterion > mycriterion)
242 return(False);
243 if (criterion < mycriterion)
244 return(True);
246 if (timeup > mytimeup)
247 return(False);
248 if (timeup < mytimeup)
249 return(True);
251 if (StrCaseCmp(global_myname(), server_name) > 0)
252 return(False);
254 return(True);
257 /*******************************************************************
258 Process an incoming election datagram packet.
259 ******************************************************************/
261 void process_election(struct subnet_record *subrec, struct packet_struct *p, const char *buf)
263 struct dgram_packet *dgram = &p->packet.dgram;
264 int version = CVAL(buf,0);
265 uint32 criterion = IVAL(buf,1);
266 int timeup = IVAL(buf,5)/1000;
267 unstring server_name;
268 struct work_record *work;
269 unstring workgroup_name;
271 START_PROFILE(election);
273 pull_ascii_nstring(server_name, sizeof(server_name), buf+13);
274 pull_ascii_nstring(workgroup_name, sizeof(workgroup_name), dgram->dest_name.name);
276 server_name[15] = 0;
278 DEBUG(3,("process_election: Election request from %s at IP %s on subnet %s for workgroup %s.\n",
279 server_name,inet_ntoa(p->ip), subrec->subnet_name, workgroup_name ));
281 DEBUG(5,("process_election: vers=%d criterion=%08x timeup=%d\n", version,criterion,timeup));
283 if(( work = find_workgroup_on_subnet(subrec, workgroup_name)) == NULL) {
284 DEBUG(0,("process_election: Cannot find workgroup %s on subnet %s.\n",
285 workgroup_name, subrec->subnet_name ));
286 goto done;
289 if (!strequal(work->work_group, lp_workgroup())) {
290 DEBUG(3,("process_election: ignoring election request for workgroup %s on subnet %s as this \
291 is not my workgroup.\n", work->work_group, subrec->subnet_name ));
292 goto done;
295 if (win_election(work, version,criterion,timeup,server_name)) {
296 /* We take precedence over the requesting server. */
297 if (!work->RunningElection) {
298 /* We weren't running an election - start running one. */
300 work->needelection = True;
301 work->ElectionCount=0;
304 /* Note that if we were running an election for this workgroup on this
305 subnet already, we just ignore the server we take precedence over. */
306 } else {
307 /* We lost. Stop participating. */
308 work->needelection = False;
310 if (work->RunningElection || AM_LOCAL_MASTER_BROWSER(work)) {
311 work->RunningElection = False;
312 DEBUG(3,("process_election: >>> Lost election for workgroup %s on subnet %s <<<\n",
313 work->work_group, subrec->subnet_name ));
314 if (AM_LOCAL_MASTER_BROWSER(work))
315 unbecome_local_master_browser(subrec, work, False);
318 done:
320 END_PROFILE(election);
323 /****************************************************************************
324 This function looks over all the workgroups known on all the broadcast
325 subnets and decides if a browser election is to be run on that workgroup.
326 It returns True if any election packets need to be sent (this will then
327 be done by run_elections().
328 ***************************************************************************/
330 bool check_elections(void)
332 struct subnet_record *subrec;
333 bool run_any_election = False;
335 for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
336 struct work_record *work;
337 for (work = subrec->workgrouplist; work; work = work->next) {
338 if (work->RunningElection) {
339 run_any_election = work->RunningElection;
343 * Start an election if we have any chance of winning.
344 * Note this is a change to the previous code, that would
345 * only run an election if nmbd was in the potential browser
346 * state. We need to run elections in any state if we're told
347 * to. JRA.
350 if (work->needelection && !work->RunningElection && lp_local_master()) {
352 * We can only run an election for a workgroup if we have
353 * registered the WORKGROUP<1e> name, as that's the name
354 * we must listen to.
356 struct nmb_name nmbname;
358 make_nmb_name(&nmbname, work->work_group, 0x1e);
359 if(find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME)==NULL) {
360 DEBUG(8,("check_elections: Cannot send election packet yet as name %s not \
361 yet registered on subnet %s\n", nmb_namestr(&nmbname), subrec->subnet_name ));
362 continue;
365 DEBUG(3,("check_elections: >>> Starting election for workgroup %s on subnet %s <<<\n",
366 work->work_group, subrec->subnet_name ));
368 work->ElectionCount = 0;
369 work->RunningElection = True;
370 work->needelection = False;
374 return run_any_election;
377 /****************************************************************************
378 Process a internal Samba message forcing an election.
379 ***************************************************************************/
381 void nmbd_message_election(struct messaging_context *msg,
382 void *private_data,
383 uint32_t msg_type,
384 struct server_id server_id,
385 DATA_BLOB *data)
387 struct subnet_record *subrec;
389 for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
390 struct work_record *work;
391 for (work = subrec->workgrouplist; work; work = work->next) {
392 if (strequal(work->work_group, lp_workgroup())) {
393 work->needelection = True;
394 work->ElectionCount=0;
395 work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;