/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   NBT netbios routines and daemon - version 2
   Copyright (C) Andrew Tridgell 1994-1996
   
   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.
   
   Module name: nameserv.c

   Revision History:

   14 jan 96: lkcl@pires.co.uk
   added multiple workgroup domain master support

   04 jul 96: lkcl@pires.co.uk
   module nameserv contains name server management functions
*/

#include "includes.h"

extern int ClientNMB;

extern int DEBUGLEVEL;

extern pstring scope;
extern pstring myname;
extern pstring ServerComment;
extern struct in_addr ipzero;
extern struct in_addr ipgrp;

extern struct subnet_record *subnetlist;

extern uint16 nb_type; /* samba's NetBIOS type */

/****************************************************************************
  remove an entry from the name list

  note: the name will _always_ be removed: it's just a matter of when.
  XXXX at present, the name is removed _even_ if a WINS server says keep it.

  ****************************************************************************/
void remove_name_entry(struct subnet_record *d, char *name,int type)
{
  /* XXXX BUG: if samba is offering WINS support, it should still broadcast
      a de-registration packet to the local subnet before removing the
      name from its local-subnet name database. */

  struct name_record n;
  struct name_record *n2=NULL;
      
  make_nmb_name(&n.name,name,type,scope);

  if ((n2 = find_name_search(&d, &n.name, FIND_SELF, ipzero)))
  {
    /* check name isn't already being de-registered */
    if (NAME_DEREG(n2->nb_flags))
      return;

    /* mark the name as in the process of deletion. */
    n2->nb_flags &= NB_DEREG;
  }

  if (ip_equal(d->bcast_ip, ipgrp))
  {
    if (lp_wins_support())
    {
        /* we are a WINS server. */
        /* XXXX assume that if we are a WINS server that we are therefore
           not pointing to another WINS server as well. this may later NOT
           actually be true
         */
        remove_netbios_name(d,name,type,SELF,ipzero);
    }
    else
    {
      /* not a WINS server: cannot just remove our own names: we have to
         release them on the network first. ask permission from the WINS
         server, or if no reply is received, then we can remove the name */

        queue_netbios_pkt_wins(d,ClientNMB,NMB_REL,NAME_RELEASE,
                 name, type, 0, 0,0,NULL,NULL,
                 False, True, ipzero, ipzero);
    }
  }
  else
  {
     /* local interface: cannot just remove our own names: we have to
        release them on the network first. once no reply is received,
        then we can remove the name. */

     queue_netbios_packet(d,ClientNMB,NMB_REL,NAME_RELEASE,
			     name, type, 0, 0,0,NULL,NULL,
			     True, True, d->bcast_ip, d->bcast_ip);
  }
}


/****************************************************************************
  add an entry to the name list
  
  big note: our name will _always_ be added (if there are no objections).
  it's just a matter of when this will be done (e.g after a time-out).

  ****************************************************************************/
void add_my_name_entry(struct subnet_record *d,char *name,int type,int nb_flags)
{
  BOOL re_reg = False;
  struct nmb_name n;

  if (!d) return;

  /* not that it particularly matters, but if the SELF name already exists,
     it must be re-registered, rather than just registered */

  make_nmb_name(&n, name, type, scope);
  if (find_name(d->namelist, &n, SELF))
	re_reg = True;

  /* XXXX BUG: if samba is offering WINS support, it should still add the
     name entry to a local-subnet name database. see rfc1001.txt 15.1.1 p28
     regarding the point about M-nodes. */

  if (ip_equal(d->bcast_ip, ipgrp))
  {
    if (lp_wins_support())
    {
      /* we are a WINS server. */
      /* XXXX assume that if we are a WINS server that we are therefore
         not pointing to another WINS server as well. this may later NOT
         actually be true
       */

      DEBUG(4,("samba as WINS server adding: "));
      /* this will call add_netbios_entry() */
      name_register_work(d, name, type, nb_flags,0, ipzero, False);
    }
    else
    {
      /* a time-to-live allows us to refresh this name with the WINS server. */
  	  queue_netbios_pkt_wins(d,ClientNMB,
				 re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
			     name, type, nb_flags, GET_TTL(0),0,NULL,NULL,
			     False, True, ipzero, ipzero);
    }
  }
  else
  {
    /* broadcast the packet, but it comes from ipzero */
  	queue_netbios_packet(d,ClientNMB,
				 re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
			     name, type, nb_flags, GET_TTL(0),0,NULL,NULL,
			     True, True, d->bcast_ip, ipzero);
  }
}


/****************************************************************************
  add the magic samba names, useful for finding samba servers
  **************************************************************************/
void add_my_names(void)
{
  BOOL wins = lp_wins_support();
  struct subnet_record *d;

  struct in_addr ip = ipzero;

  /* each subnet entry, including WINS pseudo-subnet, has SELF names */

  /* XXXX if there was a transport layer added to samba (ipx/spx etc) then
     there would be yet _another_ for-loop, this time on the transport type
   */

  for (d = subnetlist; d; d = d->next)
  {
	add_my_name_entry(d, myname,0x20,nb_type|NB_ACTIVE);
	add_my_name_entry(d, myname,0x03,nb_type|NB_ACTIVE);
	add_my_name_entry(d, myname,0x00,nb_type|NB_ACTIVE);
	add_my_name_entry(d, myname,0x1f,nb_type|NB_ACTIVE);

    /* these names are added permanently (ttl of zero) and will NOT be
       refreshed with the WINS server  */
	add_netbios_entry(d,"*",0x0,nb_type|NB_ACTIVE,0,SELF,ip,False,wins);
	add_netbios_entry(d,"__SAMBA__",0x20,nb_type|NB_ACTIVE,0,SELF,ip,False,wins);
	add_netbios_entry(d,"__SAMBA__",0x00,nb_type|NB_ACTIVE,0,SELF,ip,False,wins);

	if (lp_domain_logons()) {
	  /* 0x1c is used to find logon servers for a domain */
	  add_my_name_entry(d, my_workgroup(),0x1c,nb_type|NB_ACTIVE|NB_GROUP);
	}
  }
  if (lp_domain_master() && (d = find_subnet(ipgrp)))
  {
    struct work_record *work = find_workgroupstruct(d, lp_workgroup(), True);
    if (work && work->state == MST_NONE)
    {
      work->state = MST_DOMAIN_NONE;
      become_master(d, work);
    }
  }
}


/****************************************************************************
  remove all the samba names... from a WINS server if necessary.
  **************************************************************************/
void remove_my_names()
{
	struct subnet_record *d;

	for (d = subnetlist; d; d = d->next)
	{
		struct name_record *n, *next;

		for (n = d->namelist; n; n = next)
		{
			next = n->next;
			if (n->source == SELF)
			{
				/* get all SELF names removed from the WINS server's database */
				/* XXXX note: problem occurs if this removes the wrong one! */

				remove_name_entry(d,n->name.name, n->name.name_type);
			}
		}
	}
}


/*******************************************************************
  refresh my own names
  ******************************************************************/
void refresh_my_names(time_t t)
{
  struct subnet_record *d;

  for (d = subnetlist; d; d = d->next)
  {
    struct name_record *n;
	  
	for (n = d->namelist; n; n = n->next)
    {
      /* each SELF name has an individual time to be refreshed */
      if (n->source == SELF && n->refresh_time < time(NULL) && 
          n->death_time != 0)
      {
        add_my_name_entry(d,n->name.name,n->name.name_type,n->nb_flags);
      }
    }
  }
}


/*******************************************************************
  queries names occasionally. an over-cautious, non-trusting WINS server!

  this function has been added because nmbd could be restarted. it
  is generally a good idea to check all the names that have been
  reloaded from file.

  XXXX which names to poll and which not can be refined at a later date.
  ******************************************************************/
void query_refresh_names(void)
{
	struct name_record *n;
	struct subnet_record *d = find_subnet(ipgrp);

	static time_t lasttime = 0;
	time_t t = time(NULL);

	int count = 0;
	int name_refresh_time = NAME_POLL_REFRESH_TIME;
	int max_count = name_refresh_time * 2 / NAME_POLL_INTERVAL;
	if (max_count > 10) max_count = 10;

	name_refresh_time = NAME_POLL_INTERVAL * max_count / 2;

	/* if (!lp_poll_wins()) return; polling of registered names allowed */

	if (!d) return;

    if (!lasttime) lasttime = t;
	if (t - lasttime < NAME_POLL_INTERVAL) return;

    lasttime = time(NULL);

	for (n = d->namelist; n; n = n->next)
	{
		/* only do unique, registered names */

		if (n->source != REGISTER) continue;
		if (!NAME_GROUP(n->nb_flags)) continue;

		if (n->refresh_time < t)
		{
		  DEBUG(3,("Polling name %s\n", namestr(&n->name)));
		  
    	  queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_CONFIRM,
				n->name.name, n->name.name_type,
				0,0,0,NULL,NULL,
				False,False,n->ip,n->ip);
		  count++;
		}

		if (count >= max_count)
		{
			/* don't do too many of these at once, but do enough to
			   cover everyone in the list */
			return;
		}

		/* this name will be checked on again, if it's not removed */
		n->refresh_time += name_refresh_time;
	}
}