nmbd_namerelease.c   [plain text]

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   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 1994-1998
   
   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"

/****************************************************************************
 Deal with a response packet when releasing one of our names.
****************************************************************************/

static void release_name_response(struct subnet_record *subrec,
                       struct response_record *rrec, struct packet_struct *p)
{
  /* 
   * If we are releasing broadcast, then getting a response is an
   * error. If we are releasing unicast, then we expect to get a response.
   */

  struct nmb_packet *nmb = &p->packet.nmb;
  BOOL bcast = nmb->header.nm_flags.bcast;
  BOOL success = True;
  struct nmb_name *question_name = &rrec->packet->packet.nmb.question.question_name;
  struct nmb_name *answer_name = &nmb->answers->rr_name;
  struct in_addr released_ip;

  /* Sanity check. Ensure that the answer name in the incoming packet is the
     same as the requested name in the outgoing packet. */

  if(!nmb_name_equal(question_name, answer_name))
  {
    DEBUG(0,("release_name_response: Answer name %s differs from question \
name %s.\n", nmb_namestr(answer_name), nmb_namestr(question_name)));
    return;
  }

  if(bcast)
  {
    /* Someone sent a response. This shouldn't happen/ */
    DEBUG(1,("release_name_response: A response for releasing name %s was received on a \
broadcast subnet %s. This should not happen !\n", nmb_namestr(answer_name), subrec->subnet_name));
    return;
  }
  else
  {
    /* Unicast - check to see if the response allows us to release the name. */
    if(nmb->header.rcode != 0)
    {
      /* Error code - we were told not to release the name ! What now ! */
      success = False;

      DEBUG(0,("release_name_response: WINS server at IP %s rejected our \
name release of name %s with error code %d.\n", inet_ntoa(p->ip), 
                  nmb_namestr(answer_name), nmb->header.rcode));

    }
    else if(nmb->header.opcode == NMB_WACK_OPCODE)
    {
      /* WINS server is telling us to wait. Pretend we didn't get
         the response but don't send out any more release requests. */

      DEBUG(5,("release_name_response: WACK from WINS server %s in releasing \
name %s on subnet %s.\n", inet_ntoa(p->ip), nmb_namestr(answer_name), subrec->subnet_name));

      rrec->repeat_count = 0;
      /* How long we should wait for. */
      rrec->repeat_time = p->timestamp + nmb->answers->ttl;
      rrec->num_msgs--;
      return;
    }
  } 

  DEBUG(5,("release_name_response: %s in releasing name %s on subnet %s.\n",
        success ? "success" : "failure", nmb_namestr(answer_name), subrec->subnet_name));

  if(success)
  {
    putip((char*)&released_ip ,&nmb->answers->rdata[2]);

    if(rrec->success_fn)
      (*(release_name_success_function)rrec->success_fn)(subrec, rrec->userdata, answer_name, released_ip);
    standard_success_release( subrec, rrec->userdata, answer_name, released_ip);
  }
  else
  {
    /* We have no standard_fail_release - maybe we should add one ? */
    if(rrec->fail_fn)
      (*(release_name_fail_function)rrec->fail_fn)(subrec, rrec, answer_name);
  }

  remove_response_record(subrec, rrec);
}

/****************************************************************************
 Deal with a timeout when releasing one of our names.
****************************************************************************/

static void release_name_timeout_response(struct subnet_record *subrec,
                       struct response_record *rrec)
{
  /*
   * If we are releasing unicast, then NOT getting a response is an
   * error - we could not release the name. If we are releasing broadcast,
   * then we don't expect to get a response.
   */

  struct nmb_packet *sent_nmb = &rrec->packet->packet.nmb;
  BOOL bcast = sent_nmb->header.nm_flags.bcast;
  BOOL success = False;
  struct nmb_name *question_name = &sent_nmb->question.question_name;
  struct in_addr released_ip;

  if(bcast)
  {
    if(rrec->num_msgs == 0)
    {
      /* Not receiving a message is success for broadcast release. */
      success = True; 

      /* Get the ip address we were trying to release. */
      putip((char*)&released_ip ,&sent_nmb->additional->rdata[2]);
    }
  }
  else
  {
    /* Unicast - if no responses then it's an error. */
    if(rrec->num_msgs == 0)
    {
      DEBUG(2,("release_name_timeout_response: WINS server at address %s is not \
responding.\n", inet_ntoa(rrec->packet->ip)));

      /* Keep trying to contact the WINS server periodically. This allows
         us to work correctly if the WINS server is down temporarily when
         we want to delete the name. */

      /* Reset the number of attempts to zero and double the interval between
         retries. Max out at 5 minutes. */
      rrec->repeat_count = 3;
      rrec->repeat_interval *= 2;
      if(rrec->repeat_interval > (5 * 60))
        rrec->repeat_interval = (5 * 60);
      rrec->repeat_time = time(NULL) + rrec->repeat_interval;

      DEBUG(5,("release_name_timeout_response: increasing WINS timeout to %d seconds.\n",
              (int)rrec->repeat_interval));
      return; /* Don't remove the response record. */
    }
  }

  DEBUG(5,("release_name_timeout_response: %s in releasing name %s on subnet %s.\n",
        success ? "success" : "failure", nmb_namestr(question_name), subrec->subnet_name));

  if(success && rrec->success_fn)
  {
    if(rrec->success_fn)
      (*(release_name_success_function)rrec->success_fn)(subrec, rrec->userdata, question_name, released_ip);
    standard_success_release( subrec, rrec->userdata, question_name, released_ip);
  }
  else 
  {
    /* We have no standard_fail_release - maybe we should add one ? */
    if( rrec->fail_fn)
      (*(release_name_fail_function)rrec->fail_fn)(subrec, rrec, question_name);
  }

  remove_response_record(subrec, rrec);
}

/****************************************************************************
 Try and release one of our names.
****************************************************************************/

BOOL release_name(struct subnet_record *subrec, struct name_record *namerec,
                   release_name_success_function success_fn,
                   release_name_fail_function fail_fn,
                   struct userdata_struct *userdata)
{
  int i;

  /* Ensure it's a SELF name, and in the ACTIVE state. */
  if((namerec->data.source != SELF_NAME) || !NAME_IS_ACTIVE(namerec))
  {
    DEBUG(0,("release_name: Cannot release name %s from subnet %s. Source was %d \n",
          nmb_namestr(&namerec->name), subrec->subnet_name, namerec->data.source)); 
    return True;
  }

  /* Set the name into the deregistering state. */
  namerec->data.nb_flags |= NB_DEREG;

  /*  
   * Go through and release the name for all known ip addresses.
   * Only call the success/fail function on the last one (it should
   * only be done once).
   */

  for( i = 0; i < namerec->data.num_ips; i++)
  {
    if(queue_release_name( subrec,
        release_name_response,
        release_name_timeout_response,
        (i == (namerec->data.num_ips - 1)) ? success_fn : NULL,
        (i == (namerec->data.num_ips - 1)) ? fail_fn : NULL,
        (i == (namerec->data.num_ips - 1)) ? userdata : NULL,
        &namerec->name,
        namerec->data.nb_flags,
        namerec->data.ip[i]) == NULL)
    {
      DEBUG(0,("release_name: Failed to send packet trying to release name %s IP %s\n",
            nmb_namestr(&namerec->name), inet_ntoa(namerec->data.ip[i]) ));
      return True;
    }
  }
  return False;
}