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unexpected.c

/* 
   Unix SMB/Netbios implementation.
   Version 3.0
   handle unexpected packets
   Copyright (C) Andrew Tridgell 2000
   
   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"

static TDB_CONTEXT *tdbd = NULL;

/* the key type used in the unexpeceted packet database */
struct unexpected_key {
      enum packet_type packet_type;
      time_t timestamp;
      int count;
};



/****************************************************************************
 all unexpected packets are passed in here, to be stored in a unexpected
 packet database. This allows nmblookup and other tools to receive packets
 erroneoously sent to the wrong port by broken MS systems
  **************************************************************************/
void unexpected_packet(struct packet_struct *p)
{
      static int count;
      TDB_KEY kbuf;
      TDB_DATA dbuf;
      struct unexpected_key key;
      char buf[1024];
      int len=0;

      if (!tdbd) {
            tdbd = tdb_open_log(lock_path("unexpected.tdb"), 0, 
                         TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
                         O_RDWR | O_CREAT, 0644);
            if (!tdbd) {
                  DEBUG(0,("Failed to open unexpected.tdb\n"));
                  return;
            }
      }

      memset(buf,'\0',sizeof(buf));
      
      len = build_packet(buf, p);

      key.packet_type = p->packet_type;
      key.timestamp = p->timestamp;
      key.count = count++;

      kbuf.dptr = (char *)&key;
      kbuf.dsize = sizeof(key);
      dbuf.dptr = buf;
      dbuf.dsize = len;

      tdb_store(tdbd, kbuf, dbuf, TDB_REPLACE);
}


static time_t lastt;

/****************************************************************************
delete the record if it is too old
  **************************************************************************/
static int traverse_fn(TDB_CONTEXT *ttdb, TDB_KEY kbuf, TDB_DATA dbuf, void *state)
{
      struct unexpected_key key;

      memcpy(&key, kbuf.dptr, sizeof(key));

      if (lastt - key.timestamp > NMBD_UNEXPECTED_TIMEOUT) {
            tdb_delete(ttdb, kbuf);
      }

      return 0;
}


/****************************************************************************
delete all old unexpected packets
  **************************************************************************/
void clear_unexpected(time_t t)
{
      if (!tdbd) return;

      if ((lastt != 0) && (t < lastt + NMBD_UNEXPECTED_TIMEOUT))
            return;

      lastt = t;

      tdb_traverse(tdbd, traverse_fn, NULL);
}


static struct packet_struct *matched_packet;
static int match_id;
static enum packet_type match_type;
static const char *match_name;

/****************************************************************************
tdb traversal fn to find a matching 137 packet
  **************************************************************************/
static int traverse_match(TDB_CONTEXT *ttdb, TDB_KEY kbuf, TDB_DATA dbuf, void *state)
{
      struct unexpected_key key;
      struct packet_struct *p;

      memcpy(&key, kbuf.dptr, sizeof(key));

      if (key.packet_type != match_type) return 0;

      p = parse_packet(dbuf.dptr, dbuf.dsize, match_type);

      if ((match_type == NMB_PACKET && 
           p->packet.nmb.header.name_trn_id == match_id) ||
          (match_type == DGRAM_PACKET && 
           match_mailslot_name(p, match_name))) {
            matched_packet = p;
            return -1;
      }

      free_packet(p);

      return 0;
}


/****************************************************************************
check for a particular packet in the unexpected packet queue
  **************************************************************************/
struct packet_struct *receive_unexpected(enum packet_type packet_type, int id, 
                               const char *mailslot_name)
{
      TDB_CONTEXT *tdb2 = NULL;

      tdb2 = tdb_open_log(lock_path("unexpected.tdb"), 0, 0, O_RDONLY, 0);
      if (!tdb2) return NULL;

      matched_packet = NULL;
      match_id = id;
      match_type = packet_type;
      match_name = mailslot_name;

      tdb_traverse(tdb2, traverse_match, NULL);

      tdb_close(tdb2);

      return matched_packet;
}

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