samba-mirror/source/nameservreply.c

/* 
   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: nameservreply.c

   Revision History:

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

   04 jul 96: lkcl@pires.co.uk
   created module nameservreply containing NetBIOS reply functions

*/

#include "includes.h"

extern int ClientNMB;

extern int DEBUGLEVEL;

extern struct in_addr ipgrp;


/****************************************************************************
  add a netbios entry. respond to the (possibly new) owner.
  **************************************************************************/
void add_name_respond(struct subnet_record *d, int fd, struct in_addr from_ip,
				uint16 response_id,
				struct nmb_name *name,
				int nb_flags, int ttl, struct in_addr register_ip,
				BOOL new_owner, struct in_addr reply_to_ip)
{
	/* register the old or the new owners' ip */
	add_netbios_entry(d,name->name,name->name_type,
						nb_flags,ttl,REGISTER,register_ip,False,True);

	/* reply yes or no to the host that requested the name */
	send_name_response(fd,from_ip, response_id, NMB_REG,
				new_owner, True,
				name, nb_flags, ttl, reply_to_ip);
}

/****************************************************************************
send a registration / release response: pos/neg
**************************************************************************/
void send_name_response(int fd, struct in_addr from_ip,
				int name_trn_id, int opcode, BOOL success, BOOL recurse,
				struct nmb_name *reply_name, int nb_flags, int ttl,
				struct in_addr ip)
{
  char rdata[6];
  struct packet_struct p;

  int rcode = 0;  

  if (success == False)
  {
    /* NEGATIVE RESPONSE */
    rcode = 6;
  }
  else if (opcode == NMB_REG && recurse == False)
  {
    /* END-NODE CHALLENGE REGISTRATION RESPONSE */
	rcode = 0;
  }
  
  rdata[0] = nb_flags;
  rdata[1] = 0;
  putip(&rdata[2],(char *)&ip);
  
  p.ip = from_ip;
  p.port = NMB_PORT;
  p.fd = fd;
  p.timestamp = time(NULL);
  p.packet_type = NMB_PACKET;

  reply_netbios_packet(&p,name_trn_id,
		       rcode,opcode,opcode,recurse,
		       reply_name, 0x20, 0x1,
		       ttl, 
		       rdata, 6);
}


/****************************************************************************
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 nb_flags = nmb->additional->rdata[0];
  BOOL bcast = nmb->header.nm_flags.bcast;
  struct name_record *n;
  struct subnet_record *d = NULL;
  int search = 0;
  BOOL success = False;
  
  putip((char *)&ip,&nmb->additional->rdata[2]);  
  
  DEBUG(3,("Name release on name %s\n",
	   namestr(&nmb->question.question_name)));
  
  if (!(d = find_req_subnet(p->ip, bcast)))
  {
    DEBUG(3,("response packet: bcast %s not known\n",
			inet_ntoa(p->ip)));
    return;
  }

  if (bcast)
	search &= FIND_LOCAL;
  else
	search &= FIND_WINS;

  n = find_name_search(&d, &nmb->question.question_name, 
					search, ip);
  
  /* XXXX under what conditions should we reject the removal?? */
  if (n && n->nb_flags == nb_flags)
  {
      success = True;
      
      remove_name(d,n);
      n = NULL;
  }
  
  if (bcast) return;
  
  /* Send a NAME RELEASE RESPONSE (pos/neg) see rfc1002.txt 4.2.10-11 */
  send_name_response(p->fd,p->ip, nmb->header.name_trn_id, NMB_REL,
						success, False,
						&nmb->question.question_name, nb_flags, 0, ip);
}


/****************************************************************************
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   qname_type = question->name_type;
 
  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);

  struct subnet_record *d = NULL;
  struct name_record *n = NULL;

  BOOL success = True;
  BOOL secured_redirect = False;

  struct in_addr ip, from_ip;
  int search = 0;
  
  putip((char *)&from_ip,&nmb->additional->rdata[2]);
  ip = from_ip;
  
  DEBUG(3,("Name registration for name %s at %s\n",
	           namestr(question),inet_ntoa(ip)));
  
  if (group)
    {
      /* apparently we should return 255.255.255.255 for group queries
	 (email from MS) */
      ip = ipgrp;
    }
  
  if (!(d = find_req_subnet(p->ip, bcast)))
  {
    DEBUG(3,("response packet: bcast %s not known\n",
				inet_ntoa(p->ip)));
    return;
  }

  if (bcast)
	search &= FIND_LOCAL;
  else
	search &= FIND_WINS;

  /* see if the name already exists */
  n = find_name_search(&d, question, search, 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 */
	      
	      success = False;
	  }
	  else if(!ip_equal(ip, n->ip))
	  {
	      /* 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 still says they own it, the person who wants
		   * the name can't have it. if they do not, or are not alive, they can.
	       */

          secured_redirect = True;

	      reply_name = &n->name;
	  }
	  else
	  {
	      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;
	  }
	}

    /* XXXX bug reported by terryt@ren.pc.athabascau.ca */
    /* names that people have checked for and not found get DNSFAILed. 
       we need to update the name record if someone then registers */

    if (n->source == DNSFAIL)
      n->source = REGISTER;

  }
  else
  {
      /* add the name to our name/subnet, or WINS, database */
      n = add_netbios_entry(d,qname,qname_type,nb_flags,ttl,REGISTER,ip,
				True,!bcast);
  }
  
  /* if samba owns a unique name on a subnet, then it must respond and
     disallow the attempted registration. if the registration is
     successful by broadcast, only then is there no need to respond
     (implicit registration: see rfc1001.txt 15.2.1).
   */

  if (bcast && success) return;
  
  if (secured_redirect)
  {
    char rdata[2];

    /* XXXX luke is confused. RSVAL or SSVAL? assume NMB byte ordering */
    RSSVAL(rdata,0,(nmb->header.opcode&0xf) + ((nb_flags&0xff) << 4));
  
    /* XXXX mistake in rfc1002.txt? 4.2.16: NULL is 0xa see 4.2.1.3 
       type  = 0x0a; see rfc1002.txt 4.2.1.3 
       class = 0x01; see rfc1002.txt 4.2.16
     */

    /* send WAIT ACKNOWLEDGEMENT see rfc1002.txt 4.2.16 */
    reply_netbios_packet(p,nmb->header.name_trn_id,
		       0,NMB_WAIT_ACK,NMB_WAIT_ACK,False,
		       reply_name, 0x0a, 0x01,
		       15*1000, /* 15 seconds long enough to wait? */
		       rdata, 2);

    /* initiate some enquiries to the current owner. */
	queue_netbios_packet(d,ClientNMB,NMB_QUERY,
						 NAME_REGISTER_CHALLENGE,
						 reply_name->name,reply_name->name_type,nb_flags,0,
						 False, False, n->ip, p->ip);
  }
  else
  {
    /* Send a NAME REGISTRATION RESPONSE (pos/neg) see rfc1002.txt 4.2.13-14
       or an END-NODE CHALLENGE REGISTRATION RESPONSE see rfc1002.txt 4.2.7
     */

  	send_name_response(p->fd,p->ip, nmb->header.name_trn_id, NMB_REG,
						success, True,
						reply_name, nb_flags, ttl, ip);
  }
}


/****************************************************************************
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;
  struct subnet_record *d = NULL;
  int search = FIND_SELF;

  BOOL bcast = nmb->header.nm_flags.bcast;
  
  if (!(d = find_req_subnet(p->ip, bcast)))
  {
    DEBUG(3,("Name status req: bcast %s not known\n",
			inet_ntoa(p->ip)));
    return;
  }

  DEBUG(3,("Name status for name %s %s\n",
	   namestr(&nmb->question.question_name), inet_ntoa(p->ip)));
  
  if (bcast)
    search |= FIND_WINS;
  else
    search |= FIND_LOCAL;

  n = find_name_search(&d, &nmb->question.question_name,
				search, 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 = d->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,NMB_STATUS,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.

with broadcast name queries:

	- only reply if the query is for one of YOUR names. all other machines on
	  the network will be doing the same thing (that is, only replying to a
	  broadcast query if they own it)
	  NOTE: broadcast name queries should only be sent out by a machine
	  if they HAVEN'T been configured to use WINS. this is generally bad news
	  in a wide area tcp/ip network and should be rectified by the systems
	  administrator. USE WINS! :-)
	- the exception to this is if the query is for a Primary Domain Controller
	  type name (0x1b), in which case, a reply is sent.

	- NEVER send a negative response to a broadcast query. no-one else will!

with directed name queries:

	- if you are the WINS server, you are expected to respond with either
      a negative response, a positive response, or a wait-for-acknowledgement
      packet, and then later on a pos/neg response.

****************************************************************************/
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 bcast = nmb->header.nm_flags.bcast;
  int ttl=0;
  int rcode = 0;
  int nb_flags = 0;
  struct in_addr retip;
  char rdata[6];
  struct subnet_record *d = NULL;
  BOOL success = True;
  struct name_record *n;

  /* directed queries are for WINS server: broadcasts are local SELF queries.
     the exception is PDC names.  */

  int search = bcast ? FIND_LOCAL | FIND_SELF : FIND_WINS;
  
  if (name_type == 0x1b)
  {
    /* even if it's a broadcast, we don't ignore queries for PDC names */
    search = FIND_WINS;
  }

  if (search | FIND_LOCAL)
  {
    if (!(d = find_req_subnet(p->ip, bcast)))
    {
      DEBUG(3,("name query: bcast %s not known\n",
				    inet_ntoa(p->ip)));
      success = False;
    }
  }
  else
  {
    if (!(d = find_subnet(ipgrp)))
    {
      DEBUG(3,("name query: wins search %s not known\n",
				    inet_ntoa(p->ip)));
      success = False;
    }
  }

  DEBUG(3,("Name query "));
  
  if (search == 0)
  {
    /* eh? no criterion for searching database. help! */
    success = False;
  }

  if (success && (n = search_for_name(&d,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, or
	     we're replying on behalf of a caller because they are on a different
         subnet and cannot hear the broadcast. XXXX lp_wins_proxy should be
		 switched off in environments where broadcasts are forwarded */

      /* XXXX note: for proxy servers, we should forward the query on to
         another WINS server if the name is not in our database, or we are
         not a WINS server ourselves
       */
      ttl = n->death_time ? n->death_time - p->timestamp : GET_TTL(0);
      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,NMB_QUERY,0,True,
		       &nmb->question.question_name,
		       nmb->question.question_type,
		       nmb->question.question_class,
		       ttl,
		       rdata, success ? 6 : 0);
}