samba-mirror/source3/nameserv.c

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   NBT netbios routines and daemon - version 2
   Copyright (C) Andrew Tridgell 1994-1995
   
   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.
   
   Revision History:

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

*/

#include "includes.h"

extern int ClientNMB;
extern int ClientDGRAM;

extern int DEBUGLEVEL;

extern pstring scope;
extern BOOL CanRecurse;
extern pstring myname;
extern struct in_addr ipzero;
extern struct in_addr ipgrp;

/* netbios names database */
struct name_record *namelist;

#define GET_TTL(ttl) ((ttl)?MIN(ttl,lp_max_ttl()):lp_max_ttl())


/****************************************************************************
  true if two netbios names are equal
****************************************************************************/
static BOOL name_equal(struct nmb_name *n1,struct nmb_name *n2)
{
  if (n1->name_type != n2->name_type) return(False);

  return(strequal(n1->name,n2->name) && strequal(n1->scope,n2->scope));
}

/****************************************************************************
  add a netbios name into the namelist
  **************************************************************************/
static void add_name(struct name_record *n)
{
  struct name_record *n2;

  if (!namelist)
  {
    namelist = n;
    n->prev = NULL;
    n->next = NULL;
    return;
  }

  for (n2 = namelist; n2->next; n2 = n2->next) ;

  n2->next = n;
  n->next = NULL;
  n->prev = n2;
}

/****************************************************************************
  remove a name from the namelist. The pointer must be an element just 
  retrieved
  **************************************************************************/
void remove_name(struct name_record *n)
{
  struct name_record *nlist = namelist;

  while (nlist && nlist != n) nlist = nlist->next;

  if (nlist)
  {
    if (nlist->next) nlist->next->prev = nlist->prev;
    if (nlist->prev) nlist->prev->next = nlist->next;
    free(nlist);
  }
}


/****************************************************************************
  find a name in the domain database namelist 
  search can be:
  FIND_SELF   - look for names the samba server has added for itself
  FIND_GLOBAL - the name can be anyone. first look on the client's
                subnet, then the server's subnet, then all subnets.
  **************************************************************************/
static struct name_record *find_name_search(struct nmb_name *name,
					    enum name_search search,
					    struct in_addr ip)
{
  struct name_record *ret;
  
  for (ret = namelist; ret; ret = ret->next)
    {
      if (!name_equal(&ret->name,name)) continue;

      if (search == FIND_SELF && ret->source != SELF) continue;
      
      return ret;
    }
  
  return NULL;
}


/****************************************************************************
  dump a copy of the name table
  **************************************************************************/
void dump_names(void)
{
  struct name_record *n;
  time_t t = time(NULL);
  
  DEBUG(3,("Dump of local name table:\n"));
  
  for (n = namelist; n; n = n->next)
    {
      DEBUG(3,("%s %s TTL=%d NBFLAGS=%2x\n",
	       namestr(&n->name),
	       inet_ntoa(n->ip),
	       n->death_time?n->death_time-t:0,
	       n->nb_flags));
    }
}


/****************************************************************************
  remove an entry from the name list
  ****************************************************************************/
void remove_netbios_name(char *name,int type, enum name_source source,
			 struct in_addr ip)
{
  struct nmb_name nn;
  struct name_record *n;
  
  make_nmb_name(&nn, name, type, scope);
  n = find_name_search(&nn, FIND_GLOBAL, ip);
  
  if (n && n->source == source) remove_name(n);
}


/****************************************************************************
  add an entry to the name list
  ****************************************************************************/
struct name_record *add_netbios_entry(char *name, int type, int nb_flags, 
				      int ttl,
				      enum name_source source, 
				      struct in_addr ip,
				      BOOL new_only)
{
  struct name_record *n;
  struct name_record *n2=NULL;

  n = (struct name_record *)malloc(sizeof(*n));
  if (!n) return(NULL);

  bzero((char *)n,sizeof(*n));

  make_nmb_name(&n->name,name,type,scope);

  if ((n2 = find_name_search(&n->name, FIND_GLOBAL, new_only?ipzero:ip)))
  {
    free(n);
    if (new_only || (n2->source==SELF && source!=SELF)) return n2;
    n = n2;
  }

  if (ttl) n->death_time = time(NULL)+ttl*3;
  n->ip = ip;
  n->nb_flags = nb_flags;
  n->source = source;
  
  if (!n2) add_name(n);

  DEBUG(3,("Added netbios name %s at %s ttl=%d nb_flags=%2x\n",
	        namestr(&n->name),inet_ntoa(ip),ttl,nb_flags));

  return(n);
}


/****************************************************************************
  remove an entry from the name list
  ****************************************************************************/
void remove_name_entry(char *name,int type)
{
  if (lp_wins_support())
    {
      /* we are a WINS server. */
      remove_netbios_name(name,type,SELF,ipzero);
    }
  else
    {
      struct in_addr ip;
      ip = ipzero;
      
      queue_netbios_pkt_wins(ClientNMB,NMB_REL,NAME_RELEASE,
			     name, type, 0,
			     False, True, ip);
    }
}


/****************************************************************************
  add an entry to the name list
  ****************************************************************************/
void add_name_entry(char *name,int type,int nb_flags)
{
  /* always add our own entries */
  add_netbios_entry(name,type,nb_flags,0,SELF,ipzero,False);

  if (!lp_wins_support())
    {
      struct in_addr ip;
      ip = ipzero;
      
      queue_netbios_pkt_wins(ClientNMB,NMB_REG,NAME_REGISTER,
			     name, type, nb_flags,
			     False, True, ip);
    }
}


/****************************************************************************
  add the magic samba names, useful for finding samba servers
  **************************************************************************/
void add_my_names(void)
{
  struct in_addr ip;

  ip = ipzero;
  
  add_name_entry(myname,0x20,NB_ACTIVE);
  add_name_entry(myname,0x03,NB_ACTIVE);
  add_name_entry(myname,0x00,NB_ACTIVE);
  add_name_entry(myname,0x1f,NB_ACTIVE);
  
  add_netbios_entry("*",0x0,NB_ACTIVE,0,SELF,ip,False);
  add_netbios_entry("__SAMBA__",0x20,NB_ACTIVE,0,SELF,ip,False);
  add_netbios_entry("__SAMBA__",0x00,NB_ACTIVE,0,SELF,ip,False);

  if (lp_wins_support()) {
    /* the 0x1c name gets added by any WINS server it seems */
    add_name_entry(my_workgroup(),0x1c,NB_ACTIVE|NB_GROUP);      
  }
}

/****************************************************************************
  remove all the samba names... from a WINS server if necessary.
  **************************************************************************/
void remove_my_names()
{
  struct name_record *n;
  
  for (n = namelist; n; n = n->next)
    {
      if (n->source == SELF)
	{
	  /* get all SELF names removed from the WINS server's database */
	  remove_name_entry(n->name.name, n->name.name_type);
	}
    }
}


/*******************************************************************
  refresh my own names
  ******************************************************************/
void refresh_my_names(time_t t)
{
  static time_t lasttime = 0;

  if (t - lasttime < REFRESH_TIME) 
    return;
  lasttime = t;

  add_my_names();
}

/*******************************************************************
  expires old names in the namelist
  ******************************************************************/
void expire_names(time_t t)
{
  struct name_record *n;
  struct name_record *next;
  
  /* expire old names */
  for (n = namelist; n; n = next)
    {
      if (n->death_time && n->death_time < t)
	{
	  DEBUG(3,("Removing dead name %s\n", namestr(&n->name)));
	  
	  next = n->next;
	  
	  if (n->prev) n->prev->next = n->next;
	  if (n->next) n->next->prev = n->prev;
	  
	  if (namelist == n) namelist = n->next; 
	  
	  free(n);
	}
      else
	{
	  next = n->next;
	}
    }
}


/****************************************************************************
  response for a reg release received
  **************************************************************************/
void response_name_release(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  char *name = nmb->question.question_name.name;
  int   type = nmb->question.question_name.name_type;
  
  DEBUG(4,("response name release received\n"));
  
  if (nmb->header.rcode == 0 && nmb->answers->rdata)
    {
      struct in_addr found_ip;
      putip((char*)&found_ip,&nmb->answers->rdata[2]);
      
      if (ismyip(found_ip))
	{
	  remove_netbios_name(name,type,SELF,found_ip);
	}
    }
  else
    {
      DEBUG(1,("name registration for %s rejected!\n",
	       namestr(&nmb->question.question_name)));
    }
}


/****************************************************************************
  reply to a name release
  ****************************************************************************/
void reply_name_release(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  struct in_addr ip;
  int rcode=0;
  int opcode = nmb->header.opcode;  
  int nb_flags = nmb->additional->rdata[0];
  BOOL bcast = nmb->header.nm_flags.bcast;
  struct name_record *n;
  char rdata[6];
  
  putip((char *)&ip,&nmb->additional->rdata[2]);  
  
  DEBUG(3,("Name release on name %s rcode=%d\n",
 	   namestr(&nmb->question.question_name),rcode));
  
  n = find_name_search(&nmb->question.question_name, FIND_GLOBAL, ip);
  
  /* XXXX under what conditions should we reject the removal?? */
  if (n && n->nb_flags == nb_flags)
    {
      /* success = True;
	 rcode = 6; */
      
      remove_name(n);
      n = NULL;
    }
  
  if (bcast) return;
  
  rdata[0] = nb_flags;
  rdata[1] = 0;
  putip(&rdata[2],(char *)&ip);
  
  /* Send a NAME RELEASE RESPONSE */
  reply_netbios_packet(p,nmb->header.name_trn_id,
		       rcode,opcode,True,
		       &nmb->question.question_name,
		       nmb->question.question_type,
		       nmb->question.question_class,
		       0,
		       rdata, 6);
}


/****************************************************************************
  response for a reg request received
  **************************************************************************/
void response_name_reg(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  char *name = nmb->question.question_name.name;
  int   type = nmb->question.question_name.name_type;
  
  DEBUG(4,("response name registration received!\n"));
  
  if (nmb->header.rcode == 0 && nmb->answers->rdata)
    {
      int nb_flags = nmb->answers->rdata[0];
      struct in_addr found_ip;
      int ttl = nmb->answers->ttl;
      enum name_source source = REGISTER;
      
      putip((char*)&found_ip,&nmb->answers->rdata[2]);
      
      if (ismyip(found_ip)) source = SELF;
      
      add_netbios_entry(name,type,nb_flags,ttl,source,found_ip,True);
    }
  else
    {
      DEBUG(1,("name registration for %s rejected!\n",
	       namestr(&nmb->question.question_name)));
    }
}


/****************************************************************************
  reply to a reg request
  **************************************************************************/
void reply_name_reg(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  struct nmb_name *question = &nmb->question.question_name;
  
  struct nmb_name *reply_name = question;
  char *qname = question->name;
  int name_type  = question->name_type;
  int name_class = nmb->question.question_class;
  
  BOOL bcast = nmb->header.nm_flags.bcast;
  
  int ttl = GET_TTL(nmb->additional->ttl);
  int nb_flags = nmb->additional->rdata[0];
  BOOL group = NAME_GROUP(nb_flags);
  int rcode = 0;  
  int opcode = nmb->header.opcode;  
  
  struct name_record *n = NULL;
  BOOL success = True;
  BOOL recurse = True; /* true if samba replies yes/no: false if caller */
  /* must challenge the current owner */
  char rdata[6];
  
  struct in_addr ip, from_ip;
  
  DEBUG(3,("Name registration for name %s at %s rcode=%d\n",
	   namestr(question),inet_ntoa(ip),rcode));
  
  putip((char *)&from_ip,&nmb->additional->rdata[2]);
  ip = from_ip;
  
  if (group)
    {
      /* apparently we should return 255.255.255.255 for group queries
	 (email from MS) */
      ip = ipgrp;
    }
  
  /* see if the name already exists */
  n = find_name_search(question, FIND_GLOBAL, from_ip);
  
  if (n)
    {
      if (!group) /* unique names */
	{
	  if (n->source == SELF || NAME_GROUP(n->nb_flags))
	    {
	      /* no-one can register one of samba's names, nor can they
		 register a name that's a group name as a unique name */
	      
	      rcode = 6;
	      success = False;
	    }
	  else if(!ip_equal(ip, n->ip))
	    {
	      /* hm. this unique name doesn't belong to them. */
	      
	      /* XXXX rfc1001.txt says:
	       * if we are doing secured WINS, we must send a Wait-Acknowledge
	       * packet (WACK) to the person who wants the name, then do a
	       * name query on the person who currently owns the unique name.
	       * if the current owner is alive, the person who wants the name
	       * can't have it. if they are not alive, they can.
	       *
	       * if we are doing non-secure WINS (which is much simpler) then
	       * we send a message to the person wanting the name saying 'he
	       * owns this name: i don't want to hear from you ever again
	       * until you've checked with him if you can have it!'. we then
	       * abandon the registration. once the person wanting the name
	       * has checked with the current owner, they will repeat the
	       * registration packet if the current owner is dead or doesn't
	       * want the name.
	       */
	      
	      /* non-secured WINS implementation: caller is responsible
		 for checking with current owner of name, then getting back
		 to us... IF current owner no longer owns the unique name */
	      
	      rcode = 0;
	      success = False;
	      recurse = False;
	      
	      /* we inform on the current owner to the caller (which is
		 why it's non-secure */
	      
	      reply_name = &n->name;
	      
	      /* name_type  = ?;
		 name_class = ?;
		 XXXX sorry, guys: i really can't see what name_type
		 and name_class should be set to according to rfc1001 */
	    }
	  else
	    {
	      /* XXXX removed code that checked with the owner of a name */
	      
	      n->ip = ip;
	      n->death_time = ttl?p->timestamp+ttl*3:0;
	      DEBUG(3,("%s owner: %s\n",namestr(&n->name),inet_ntoa(n->ip)));
	    }
	}
      else
	{
	  /* refresh the name */
	  if (n->source != SELF)
	    {
	      n->death_time = ttl?p->timestamp + ttl*3:0;
	    }
	}
    }
  else
    {
      /* add the name to our subnet/name database */
      n = add_netbios_entry(qname,name_type,nb_flags,ttl,REGISTER,ip,True);
    }
  
  if (bcast) return;
  
  if (success)
    {
      update_from_reg(nmb->question.question_name.name,
		      nmb->question.question_name.name_type, from_ip);
    }
  
  rdata[0] = nb_flags;
  rdata[1] = 0;
  putip(&rdata[2],(char *)&ip);
  
  /* Send a NAME REGISTRATION RESPONSE (pos/neg)
     or and END-NODE CHALLENGE REGISTRATION RESPONSE */
  reply_netbios_packet(p,nmb->header.name_trn_id,
		       rcode,opcode,recurse,
		       reply_name, name_type, name_class,
		       ttl,
		       rdata, 6);
}


/****************************************************************************
  reply to a name status query
  ****************************************************************************/
void reply_name_status(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  char *qname   = nmb->question.question_name.name;
  int ques_type = nmb->question.question_name.name_type;
  char rdata[MAX_DGRAM_SIZE];
  char *countptr, *buf, *bufend;
  int names_added;
  struct name_record *n;
  
  DEBUG(3,("Name status for name %s %s\n",
 	   namestr(&nmb->question.question_name), inet_ntoa(p->ip)));
  
  n = find_name_search(&nmb->question.question_name,FIND_GLOBAL, p->ip);
  
  if (!n) return;
    
  /* XXXX hack, we should calculate exactly how many will fit */
  bufend = &rdata[MAX_DGRAM_SIZE] - 18;
  countptr = buf = rdata;
  buf += 1;
  
  names_added = 0;
  
  for (n = namelist ; n && buf < bufend; n = n->next) 
    {
      int name_type = n->name.name_type;
      
      if (n->source != SELF) continue;
      
      /* start with first bit of putting info in buffer: the name */
      
      bzero(buf,18);
      sprintf(buf,"%-15.15s",n->name.name);
      strupper(buf);
      
      /* now check if we want to exclude other workgroup names
	 from the response. if we don't exclude them, windows clients
	 get confused and will respond with an error for NET VIEW */
      
      if (name_type >= 0x1b && name_type <= 0x20 && 
	  ques_type >= 0x1b && ques_type <= 0x20)
	{
	  if (!strequal(qname, n->name.name)) continue;
	}
      
      /* carry on putting name info in buffer */
      
      buf[15] = name_type;
      buf[16]  = n->nb_flags;
      
      buf += 18;
      
      names_added++;
    }
    
  SCVAL(countptr,0,names_added);
  
  /* XXXXXXX we should fill in more fields of the statistics structure */
  bzero(buf,64);
  {
    extern int num_good_sends,num_good_receives;
    SIVAL(buf,20,num_good_sends);
    SIVAL(buf,24,num_good_receives);
  }
  
  SIVAL(buf,46,0xFFB8E5); /* undocumented - used by NT */
  
  buf += 64;
  
  /* Send a POSITIVE NAME STATUS RESPONSE */
  reply_netbios_packet(p,nmb->header.name_trn_id,
		       0,0,True,
		       &nmb->question.question_name,
		       nmb->question.question_type,
		       nmb->question.question_class,
		       0,
		       rdata,PTR_DIFF(buf,rdata));
}


/***************************************************************************
  reply to a name query
  ****************************************************************************/
static struct name_record *search_for_name(struct nmb_name *question,
					   struct in_addr ip, int Time, 
					   enum name_search search)
{
  int name_type = question->name_type;
  char *qname = question->name;
  BOOL dns_type = name_type == 0x20 || name_type == 0;
  
  struct name_record *n;
  
  DEBUG(3,("Search for %s from %s - ", namestr(question), inet_ntoa(ip)));
  
  /* first look up name in cache. use ip as well as name to locate it */
  n = find_name_search(question,search,ip);
  
  /* now try DNS lookup. */
  if (!n)
    {
      struct in_addr dns_ip;
      unsigned long a;
      
      /* only do DNS lookups if the query is for type 0x20 or type 0x0 */
      if (!dns_type)
	{
	  DEBUG(3,("types 0x20 0x1b 0x0 only: name not found\n"));
	  return NULL;
	}
      
      /* look it up with DNS */      
      a = interpret_addr(qname);
      
      putip((char *)&dns_ip,(char *)&a);
      
      if (!a)
	{
	  /* no luck with DNS. We could possibly recurse here XXXX */
	  /* if this isn't a bcast then we should send a negative reply XXXX */
	  DEBUG(3,("no recursion\n"));
	  add_netbios_entry(qname,name_type,NB_ACTIVE,60*60,DNSFAIL,dns_ip,True);
	  return NULL;
	}
      
      /* add it to our cache of names. give it 2 hours in the cache */
      n = add_netbios_entry(qname,name_type,NB_ACTIVE,2*60*60,DNS,dns_ip,True);
      
      /* failed to add it? yikes! */
      if (!n) return NULL;
    }
  
  /* is our entry already dead? */
  if (n->death_time)
    {
      if (n->death_time < Time) return False;
    }
  
  /* it may have been an earlier failure */
  if (n->source == DNSFAIL)
    {
      DEBUG(3,("DNSFAIL\n"));
      return NULL;
    }
  
  DEBUG(3,("OK %s\n",inet_ntoa(n->ip)));      
  
  return n;
}



/***************************************************************************
  reply to a name query
  ****************************************************************************/
void reply_name_query(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  struct nmb_name *question = &nmb->question.question_name;
  int name_type = question->name_type;
  BOOL dns_type = name_type == 0x20 || name_type == 0; 
  BOOL bcast = nmb->header.nm_flags.bcast;
  int ttl=0;
  int rcode = 0;
  int nb_flags = 0;
  struct in_addr retip;
  char rdata[6];
  BOOL success = True;
  struct name_record *n;
  enum name_search search = (dns_type || name_type == 0x1b) ?
    FIND_GLOBAL : FIND_SELF;

  DEBUG(3,("Name query "));
  
  if ((n = search_for_name(question,p->ip,p->timestamp, search)))
    {
      /* don't respond to broadcast queries unless the query is for
	 a name we own or it is for a Primary Domain Controller name */
      if (bcast && n->source != SELF && name_type != 0x1b)
	{
	  if (!lp_wins_proxy() || same_net(p->ip,n->ip,*iface_nmask(p->ip))) {
	    /* never reply with a negative response to broadcast queries */
	    return;
	  }
	}

      /* name is directed query, or it's self, or it's a PDC type name */
      ttl = n->death_time - p->timestamp;
      retip = n->ip;
      nb_flags = n->nb_flags;
    }
  else
    {
      if (bcast) return; /* never reply negative response to bcasts */
      success = False;
    }

  /* if the IP is 0 then substitute my IP */
  if (zero_ip(retip)) retip = *iface_ip(p->ip);
  
  if (success)
    {
      rcode = 0;
      DEBUG(3,("OK %s\n",inet_ntoa(retip)));      
    }
  else
    {
      rcode = 3;
      DEBUG(3,("UNKNOWN\n"));      
    }
  
  if (success)
    {
      rdata[0] = nb_flags;
      rdata[1] = 0;
      putip(&rdata[2],(char *)&retip);
    }
  
  reply_netbios_packet(p,nmb->header.name_trn_id,
		       rcode,0,True,
		       &nmb->question.question_name,
		       nmb->question.question_type,
		       nmb->question.question_class,
		       ttl,
		       rdata, success ? 6 : 0);
}



/****************************************************************************
response from a name query
****************************************************************************/
static void response_netbios_packet(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;
  struct nmb_name *question = &nmb->question.question_name;
  char *qname = question->name;
  BOOL bcast = nmb->header.nm_flags.bcast;
  struct name_response_record *n;

  if (nmb->answers == NULL)
    {
      DEBUG(3,("NMB packet response from %s (bcast=%s) - UNKNOWN\n",
	       inet_ntoa(p->ip),
	       BOOLSTR(bcast)));
      return;
    }
  
  if (nmb->answers->rr_type == NMB_STATUS) {
    DEBUG(3,("Name status "));
  }

  if (nmb->answers->rr_type == NMB_QUERY)	{
    DEBUG(3,("Name query "));
  }

  if (nmb->answers->rr_type == NMB_REG) {
    DEBUG(3,("Name registration "));
  }

  if (nmb->answers->rr_type == NMB_REL) {
    DEBUG(3,("Name release "));
  }

  DEBUG(3,("response for %s from %s (bcast=%s)\n",
	   namestr(&nmb->answers->rr_name),
	   inet_ntoa(p->ip),
	   BOOLSTR(bcast)));
  
  if (!(n = find_name_query(nmb->header.name_trn_id))) {
    DEBUG(3,("unknown response (received too late or from nmblookup?)\n"));
    return;
  }

  n->num_msgs++; /* count number of responses received */

  switch (n->cmd_type)
    {
    case MASTER_SERVER_CHECK     : DEBUG(4,("MASTER_SVR_CHECK\n")); break;
    case SERVER_CHECK            : DEBUG(4,("SERVER_CHECK\n")); break;
    case FIND_MASTER             : DEBUG(4,("FIND_MASTER\n")); break;
    case NAME_STATUS_MASTER_CHECK: DEBUG(4,("NAME_STAT_MST_CHK\n")); break;
    case NAME_STATUS_CHECK       : DEBUG(4,("NAME_STATUS_CHECK\n")); break;
    case CHECK_MASTER            : DEBUG(4,("CHECK_MASTER\n")); break;
    case NAME_CONFIRM_QUERY      : DEBUG(4,("NAME_CONFIRM_QUERY\n")); break;
    default: break;
    }
  switch (n->cmd_type)
    {
    case MASTER_SERVER_CHECK:
    case SERVER_CHECK:
    case FIND_MASTER:
      {
	if (nmb->answers->rr_type == NMB_QUERY)
	  {
	    enum cmd_type cmd = (n->cmd_type == MASTER_SERVER_CHECK) ?
	      NAME_STATUS_MASTER_CHECK :
	      NAME_STATUS_CHECK;
	    if (n->num_msgs > 1 && !strequal(qname,n->name.name))
	      {
		/* one subnet, one master browser per workgroup */
		/* XXXX force an election? */
		DEBUG(1,("more than one master browser replied!\n"));
	      }
	    
	    /* initiate a name status check on the server that replied */
	    queue_netbios_packet(ClientNMB,NMB_STATUS, cmd,
				 nmb->answers->rr_name.name,
				 nmb->answers->rr_name.name_type,0,
				 False,False,n->to_ip);
	  }
	else
	  {
	    DEBUG(1,("Name query reply has wrong answer rr_type\n"));
	  }
	break;
      }
      
    case NAME_STATUS_MASTER_CHECK:
    case NAME_STATUS_CHECK:
      {
	if (nmb->answers->rr_type == NMB_STATUS)
	  {
	    /* NMB_STATUS arrives: contains the workgroup name 
	       and server name we require */
	    struct nmb_name name;
	    fstring serv_name;
	    
	    if (interpret_node_status(nmb->answers->rdata,
				      &name,0x1d,serv_name,p->ip))
	      {
		if (*serv_name)
		  {
		    sync_server(n->cmd_type,serv_name,
				name.name,name.name_type,
				n->to_ip);
		  }
	      }
	    else
	      {
		DEBUG(1,("No 0x1d name type in interpret_node_status()\n"));
	      }
	  }
	else
	  {
	    DEBUG(1,("Name status reply has wrong answer rr_type\n"));
	  }
	break;
      }
      
    case CHECK_MASTER:
      {
	/* no action required here. it's when NO responses are received
	   that we need to do something (see expire_name_query_entries) */
	
	DEBUG(4, ("Master browser exists for %s at %s\n",
		  namestr(&n->name),
		  inet_ntoa(n->to_ip)));
	if (n->num_msgs > 1)
	  {
	    DEBUG(1,("more than one master browser!\n"));
	  }
	if (nmb->answers->rr_type != NMB_QUERY)
	  {
	    DEBUG(1,("Name query reply has wrong answer rr_type\n"));
	  }
	break;
      }
    case NAME_CONFIRM_QUERY:
      {
	DEBUG(4, ("Name query at WINS server: %s at %s - ",
		  namestr(&n->name),
		  inet_ntoa(n->to_ip)));
	if (nmb->header.rcode == 0 && nmb->answers->rdata)
	  {
	    int nb_flags = nmb->answers->rdata[0];
	    struct in_addr found_ip;
	    putip((char*)&found_ip,&nmb->answers->rdata[2]);
	    
	    DEBUG(4, (" OK: %s\n", inet_ntoa(found_ip)));
	    add_netbios_entry(nmb->answers->rr_name.name,
			      nmb->answers->rr_name.name_type,
			      nb_flags,GET_TTL(0),STATUS_QUERY,found_ip,False);
	  }
	else
	  {
	    DEBUG(4, (" NEGATIVE RESPONSE\n"));
	  }
	
	break;
      }
    default:
      {
	DEBUG(0,("unknown command received in response_netbios_packet\n"));
	break;
      }
    }
}


/****************************************************************************
  process a nmb packet
  ****************************************************************************/
void process_nmb(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;

  debug_nmb_packet(p);

  switch (nmb->header.opcode) 
    {
    case 5:
    case 8:
    case 9:
      {
	if (nmb->header.qdcount==0 || nmb->header.arcount==0) break;
	if (nmb->header.response)
	  response_name_reg(p);
	else
	  reply_name_reg(p);
	break;
      }
      
    case 0:
      {
	if (nmb->header.response)
	  {
	    switch (nmb->question.question_type)
	      {
	      case 0x0:
		{
		  response_netbios_packet(p);
		  break;
		}
	      }
	    return;
	  }
	else if (nmb->header.qdcount>0) 
	  {
	    switch (nmb->question.question_type)
	      {
	      case NMB_QUERY:
		{
		  reply_name_query(p);
		  break;
		}
	      case NMB_STATUS:
		{
		  reply_name_status(p);
		  break;
		}
	      }
	    return;
	  }
	break;
      }
      
    case 6:
      {
	if (nmb->header.qdcount==0 || nmb->header.arcount==0)
	  {
	    DEBUG(2,("netbios release packet rejected\n"));
	    break;
	  }
	
	if (nmb->header.response)
	  response_name_release(p);
	else
	  reply_name_release(p);
	break;
      }
    }
}