1 files changed, 348 insertions, 0 deletions
diff --git a/source/nmbd/nmbd_elections.c b/source/nmbd/nmbd_elections.c
new file mode 100644
index 00000000000..5c3c4c7a013
--- /dev/null
+++ b/source/nmbd/nmbd_elections.c
@@ -0,0 +1,348 @@
+/* 
+   Unix SMB/Netbios implementation.
+   Version 1.9.
+   NBT netbios routines and daemon - version 2
+   Copyright (C) Andrew Tridgell 1994-1997
+   Copyright (C) Luke Kenneth Casson Leighton 1994-1997 
+   Copyright (C) Jeremy Allison 1994-1997
+   
+   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"
+
+extern int DEBUGLEVEL;
+
+extern pstring myname;
+extern fstring myworkgroup;
+
+/* Election parameters. */
+extern time_t StartupTime;
+
+/****************************************************************************
+  Send an election datagram packet.
+**************************************************************************/
+static void send_election_dgram(struct subnet_record *subrec, char *workgroup_name,
+                                uint32 criterion, int timeup,char *server_name)
+{
+  pstring outbuf;
+  char *p;
+
+  DEBUG(2,("send_election_dgram: Sending election packet for workgroup %s on subnet %s\n",
+	workgroup_name, subrec->subnet_name ));
+
+  bzero(outbuf,sizeof(outbuf));
+  p = outbuf;
+  CVAL(p,0) = ANN_Election; /* Election opcode. */
+  p++;
+
+  CVAL(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;
+  pstrcpy(p,server_name);
+  strupper(p);
+  p = skip_string(p,1);
+  
+  send_mailslot(False, BROWSE_MAILSLOT, outbuf, PTR_DIFF(p,outbuf),
+                server_name, 0,
+                workgroup_name, 0x1e,
+                subrec->bcast_ip, subrec->myip);
+}
+
+/*******************************************************************
+ 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)
+{
+  DEBUG(3,("check_for_master_browser_success: Local master browser for workgroup %s exists at \
+IP %s (just checking).\n", answer_name->name, 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)
+{
+  char *workgroup_name = question_name->name;
+  struct work_record *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, myworkgroup))
+  {
+
+    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, myname);
+    }
+  }
+}
+
+/*******************************************************************
+  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;
+  char *workgroup_name = myworkgroup;
+
+  if (!lastrun)
+    lastrun = t;
+
+  if (t < (lastrun + (CHECK_TIME_MST_BROWSE * 60)))
+    return;
+
+  lastrun = t;
+
+  dump_workgroups();
+
+  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 a second - note */
+  if (lastime && (t - lastime <= 0))
+    return;
+  
+  lastime = t;
+  
+  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)
+      {
+        send_election_dgram(subrec, work->work_group, work->ElectionCriterion,
+                      t - StartupTime, 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);
+        }
+      }
+    }
+  }
+}
+
+/*******************************************************************
+  Determine if I win an election.
+******************************************************************/
+
+static BOOL win_election(struct work_record *work, int version,
+                         uint32 criterion, int timeup, 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, 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(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;
+  char *server_name = buf+13;
+  struct work_record *work;
+  char *workgroup_name = dgram->dest_name.name;
+
+  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 ));
+    return;
+  }
+
+  if (!strequal(work->work_group, myworkgroup))
+  {
+    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 ));
+    return;
+  }
+
+  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);
+    }
+  }
+}
+
+/****************************************************************************
+  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;
+
+      /* Only start an election if we are in the potential browser state. */
+      if (work->needelection && !work->RunningElection && AM_POTENTIAL_MASTER_BROWSER(work))
+      {
+        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;
+}