--- /dev/null
+/*
+ Unix SMB/CIFS implementation.
+ NBT netbios routines and daemon - version 2
+ Copyright (C) Andrew Tridgell 1994-1998
+ Copyright (C) Luke Kenneth Casson Leighton 1994-1998
+ Copyright (C) Jeremy Allison 1994-2003
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include "includes.h"
+
+/* Election parameters. */
+extern time_t StartupTime;
+
+/****************************************************************************
+ Send an election datagram packet.
+**************************************************************************/
+
+static void send_election_dgram(struct subnet_record *subrec, const char *workgroup_name,
+ uint32 criterion, int timeup,const char *server_name)
+{
+ pstring outbuf;
+ unstring srv_name;
+ char *p;
+
+ DEBUG(2,("send_election_dgram: Sending election packet for workgroup %s on subnet %s\n",
+ workgroup_name, subrec->subnet_name ));
+
+ memset(outbuf,'\0',sizeof(outbuf));
+ p = outbuf;
+ SCVAL(p,0,ANN_Election); /* Election opcode. */
+ p++;
+
+ SCVAL(p,0,((criterion == 0 && timeup == 0) ? 0 : ELECTION_VERSION));
+ SIVAL(p,1,criterion);
+ SIVAL(p,5,timeup*1000); /* ms - Despite what the spec says. */
+ p += 13;
+ unstrcpy(srv_name, server_name);
+ strupper_m(srv_name);
+ /* The following call does UNIX -> DOS charset conversion. */
+ pstrcpy_base(p, srv_name, outbuf);
+ p = skip_string(p,1);
+
+ send_mailslot(False, BROWSE_MAILSLOT, outbuf, PTR_DIFF(p,outbuf),
+ global_myname(), 0,
+ workgroup_name, 0x1e,
+ subrec->bcast_ip, subrec->myip, DGRAM_PORT);
+}
+
+/*******************************************************************
+ We found a current master browser on one of our broadcast interfaces.
+******************************************************************/
+
+static void check_for_master_browser_success(struct subnet_record *subrec,
+ struct userdata_struct *userdata,
+ struct nmb_name *answer_name,
+ struct in_addr answer_ip, struct res_rec *rrec)
+{
+ unstring aname;
+ pull_ascii_nstring(aname, sizeof(aname), answer_name->name);
+ DEBUG(3,("check_for_master_browser_success: Local master browser for workgroup %s exists at \
+IP %s (just checking).\n", aname, inet_ntoa(answer_ip) ));
+}
+
+/*******************************************************************
+ We failed to find a current master browser on one of our broadcast interfaces.
+******************************************************************/
+
+static void check_for_master_browser_fail( struct subnet_record *subrec,
+ struct response_record *rrec,
+ struct nmb_name *question_name,
+ int fail_code)
+{
+ unstring workgroup_name;
+ struct work_record *work;
+
+ pull_ascii_nstring(workgroup_name,sizeof(workgroup_name),question_name->name);
+
+ work = find_workgroup_on_subnet(subrec, workgroup_name);
+ if(work == NULL) {
+ DEBUG(0,("check_for_master_browser_fail: Unable to find workgroup %s on subnet %s.=\n",
+ workgroup_name, subrec->subnet_name ));
+ return;
+ }
+
+ if (strequal(work->work_group, lp_workgroup())) {
+
+ if (lp_local_master()) {
+ /* We have discovered that there is no local master
+ browser, and we are configured to initiate
+ an election that we will participate in.
+ */
+ DEBUG(2,("check_for_master_browser_fail: Forcing election on workgroup %s subnet %s\n",
+ work->work_group, subrec->subnet_name ));
+
+ /* Setting this means we will participate when the
+ election is run in run_elections(). */
+ work->needelection = True;
+ } else {
+ /* We need to force an election, because we are configured
+ not to become the local master, but we still need one,
+ having detected that one doesn't exist.
+ */
+ send_election_dgram(subrec, work->work_group, 0, 0, "");
+ }
+ }
+}
+
+/*******************************************************************
+ Ensure there is a local master browser for a workgroup on our
+ broadcast interfaces.
+******************************************************************/
+
+void check_master_browser_exists(time_t t)
+{
+ static time_t lastrun=0;
+ struct subnet_record *subrec;
+ const char *workgroup_name = lp_workgroup();
+
+ if (!lastrun)
+ lastrun = t;
+
+ if (t < (lastrun + (CHECK_TIME_MST_BROWSE * 60)))
+ return;
+
+ lastrun = t;
+
+ dump_workgroups(False);
+
+ for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
+ struct work_record *work;
+
+ for (work = subrec->workgrouplist; work; work = work->next) {
+ if (strequal(work->work_group, workgroup_name) && !AM_LOCAL_MASTER_BROWSER(work)) {
+ /* Do a name query for the local master browser on this net. */
+ query_name( subrec, work->work_group, 0x1d,
+ check_for_master_browser_success,
+ check_for_master_browser_fail,
+ NULL);
+ }
+ }
+ }
+}
+
+/*******************************************************************
+ Run an election.
+******************************************************************/
+
+void run_elections(time_t t)
+{
+ static time_t lastime = 0;
+
+ struct subnet_record *subrec;
+
+ /* Send election packets once every 2 seconds - note */
+ if (lastime && (t - lastime < 2))
+ return;
+
+ lastime = t;
+
+ START_PROFILE(run_elections);
+ for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
+ struct work_record *work;
+
+ for (work = subrec->workgrouplist; work; work = work->next) {
+ if (work->RunningElection) {
+ /*
+ * We can only run an election for a workgroup if we have
+ * registered the WORKGROUP<1e> name, as that's the name
+ * we must listen to.
+ */
+ struct nmb_name nmbname;
+
+ make_nmb_name(&nmbname, work->work_group, 0x1e);
+ if(find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME)==NULL) {
+ DEBUG(8,("run_elections: Cannot send election packet yet as name %s not \
+yet registered on subnet %s\n", nmb_namestr(&nmbname), subrec->subnet_name ));
+ continue;
+ }
+
+ send_election_dgram(subrec, work->work_group, work->ElectionCriterion,
+ t - StartupTime, global_myname());
+
+ if (work->ElectionCount++ >= 4) {
+ /* Won election (4 packets were sent out uncontested. */
+ DEBUG(2,("run_elections: >>> Won election for workgroup %s on subnet %s <<<\n",
+ work->work_group, subrec->subnet_name ));
+
+ work->RunningElection = False;
+
+ become_local_master_browser(subrec, work);
+ }
+ }
+ }
+ }
+ END_PROFILE(run_elections);
+}
+
+/*******************************************************************
+ Determine if I win an election.
+******************************************************************/
+
+static BOOL win_election(struct work_record *work, int version,
+ uint32 criterion, int timeup, const char *server_name)
+{
+ int mytimeup = time(NULL) - StartupTime;
+ uint32 mycriterion = work->ElectionCriterion;
+
+ /* If local master is false then never win in election broadcasts. */
+ if(!lp_local_master()) {
+ DEBUG(3,("win_election: Losing election as local master == False\n"));
+ return False;
+ }
+
+ DEBUG(4,("win_election: election comparison: %x:%x %x:%x %d:%d %s:%s\n",
+ version, ELECTION_VERSION,
+ criterion, mycriterion,
+ timeup, mytimeup,
+ server_name, global_myname()));
+
+ if (version > ELECTION_VERSION)
+ return(False);
+ if (version < ELECTION_VERSION)
+ return(True);
+
+ if (criterion > mycriterion)
+ return(False);
+ if (criterion < mycriterion)
+ return(True);
+
+ if (timeup > mytimeup)
+ return(False);
+ if (timeup < mytimeup)
+ return(True);
+
+ if (StrCaseCmp(global_myname(), server_name) > 0)
+ return(False);
+
+ return(True);
+}
+
+/*******************************************************************
+ Process an incoming election datagram packet.
+******************************************************************/
+
+void process_election(struct subnet_record *subrec, struct packet_struct *p, char *buf)
+{
+ struct dgram_packet *dgram = &p->packet.dgram;
+ int version = CVAL(buf,0);
+ uint32 criterion = IVAL(buf,1);
+ int timeup = IVAL(buf,5)/1000;
+ unstring server_name;
+ struct work_record *work;
+ unstring workgroup_name;
+
+ pull_ascii_nstring(server_name, sizeof(server_name), buf+13);
+ pull_ascii_nstring(workgroup_name, sizeof(workgroup_name), dgram->dest_name.name);
+
+ START_PROFILE(election);
+ server_name[15] = 0;
+
+ DEBUG(3,("process_election: Election request from %s at IP %s on subnet %s for workgroup %s.\n",
+ server_name,inet_ntoa(p->ip), subrec->subnet_name, workgroup_name ));
+
+ DEBUG(5,("process_election: vers=%d criterion=%08x timeup=%d\n", version,criterion,timeup));
+
+ if(( work = find_workgroup_on_subnet(subrec, workgroup_name)) == NULL) {
+ DEBUG(0,("process_election: Cannot find workgroup %s on subnet %s.\n",
+ workgroup_name, subrec->subnet_name ));
+ goto done;
+ }
+
+ if (!strequal(work->work_group, lp_workgroup())) {
+ DEBUG(3,("process_election: ignoring election request for workgroup %s on subnet %s as this \
+is not my workgroup.\n", work->work_group, subrec->subnet_name ));
+ goto done;
+ }
+
+ if (win_election(work, version,criterion,timeup,server_name)) {
+ /* We take precedence over the requesting server. */
+ if (!work->RunningElection) {
+ /* We weren't running an election - start running one. */
+
+ work->needelection = True;
+ work->ElectionCount=0;
+ }
+
+ /* Note that if we were running an election for this workgroup on this
+ subnet already, we just ignore the server we take precedence over. */
+ } else {
+ /* We lost. Stop participating. */
+ work->needelection = False;
+
+ if (work->RunningElection || AM_LOCAL_MASTER_BROWSER(work)) {
+ work->RunningElection = False;
+ DEBUG(3,("process_election: >>> Lost election for workgroup %s on subnet %s <<<\n",
+ work->work_group, subrec->subnet_name ));
+ if (AM_LOCAL_MASTER_BROWSER(work))
+ unbecome_local_master_browser(subrec, work, False);
+ }
+ }
+done:
+
+ END_PROFILE(election);
+}
+
+/****************************************************************************
+ This function looks over all the workgroups known on all the broadcast
+ subnets and decides if a browser election is to be run on that workgroup.
+ It returns True if any election packets need to be sent (this will then
+ be done by run_elections().
+***************************************************************************/
+
+BOOL check_elections(void)
+{
+ struct subnet_record *subrec;
+ BOOL run_any_election = False;
+
+ for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
+ struct work_record *work;
+ for (work = subrec->workgrouplist; work; work = work->next) {
+ run_any_election |= work->RunningElection;
+
+ /*
+ * Start an election if we have any chance of winning.
+ * Note this is a change to the previous code, that would
+ * only run an election if nmbd was in the potential browser
+ * state. We need to run elections in any state if we're told
+ * to. JRA.
+ */
+
+ if (work->needelection && !work->RunningElection && lp_local_master()) {
+ /*
+ * We can only run an election for a workgroup if we have
+ * registered the WORKGROUP<1e> name, as that's the name
+ * we must listen to.
+ */
+ struct nmb_name nmbname;
+
+ make_nmb_name(&nmbname, work->work_group, 0x1e);
+ if(find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME)==NULL) {
+ DEBUG(8,("check_elections: Cannot send election packet yet as name %s not \
+yet registered on subnet %s\n", nmb_namestr(&nmbname), subrec->subnet_name ));
+ continue;
+ }
+
+ DEBUG(3,("check_elections: >>> Starting election for workgroup %s on subnet %s <<<\n",
+ work->work_group, subrec->subnet_name ));
+
+ work->ElectionCount = 0;
+ work->RunningElection = True;
+ work->needelection = False;
+ }
+ }
+ }
+ return run_any_election;
+}
+
+/****************************************************************************
+ Process a internal Samba message forcing an election.
+***************************************************************************/
+
+void nmbd_message_election(int msg_type, struct process_id src,
+ void *buf, size_t len)
+{
+ struct subnet_record *subrec;
+
+ for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
+ struct work_record *work;
+ for (work = subrec->workgrouplist; work; work = work->next) {
+ if (strequal(work->work_group, lp_workgroup())) {
+ work->needelection = True;
+ work->ElectionCount=0;
+ work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
+ }
+ }
+ }
+}
projects / samba / blobdiff