Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 395 insertions, 0 deletions

diff --git a/source3/nmbd/nmbd_elections.c b/source3/nmbd/nmbd_elections.c
new file mode 100644
index 0000000..41470ea
--- /dev/null
+++ b/source3/nmbd/nmbd_elections.c
@@ -0,0 +1,395 @@
+/* 
+   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 3 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, see <http://www.gnu.org/licenses/>.
+   
+*/
+
+#include "includes.h"
+#include "nmbd/nmbd.h"
+#include "lib/util/string_wrappers.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_t criterion, int timeup,const char *server_name)
+{
+	char outbuf[1024];
+	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);
+	if (!strupper_m(srv_name)) {
+		DEBUG(2,("strupper_m failed for %s\n", srv_name));
+		return;
+	}
+	/* The following call does UNIX -> DOS charset conversion. */
+	push_ascii(p, srv_name, sizeof(outbuf)-PTR_DIFF(p,outbuf)-1, STR_TERMINATE);
+	p = skip_string(outbuf,sizeof(outbuf),p);
+
+	send_mailslot(False, BROWSE_MAILSLOT, outbuf, PTR_DIFF(p,outbuf),
+		lp_netbios_name(), 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 (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;
+  
+	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, lp_netbios_name());
+	      
+				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_t criterion, int timeup, const char *server_name)
+{  
+	int mytimeup = time(NULL) - StartupTime;
+	uint32_t 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, lp_netbios_name()));
+
+	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_m(lp_netbios_name(), server_name) > 0)
+		return(False);
+  
+	return(True);
+}
+
+/*******************************************************************
+  Process an incoming election datagram packet.
+******************************************************************/
+
+void process_election(struct subnet_record *subrec, struct packet_struct *p, const char *buf)
+{
+	struct dgram_packet *dgram = &p->packet.dgram;
+	int version = CVAL(buf,0);
+	uint32_t 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);
+
+	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:
+	return;
+}
+
+/****************************************************************************
+  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) {
+			if (work->RunningElection) {
+				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(struct messaging_context *msg,
+			   void *private_data,
+			   uint32_t msg_type,
+			   struct server_id server_id,
+			   DATA_BLOB *data)
+{
+	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;
+			}
+		}
+	}
+}