source: branches/samba-3.0/source/libsmb/unexpected.c

/* 
   Unix SMB/CIFS implementation.
   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_DATA kbuf, 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);

        ZERO_STRUCT(key);       /* needed for potential alignment */

        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_DATA kbuf, TDB_DATA dbuf, void *state)
{
        struct unexpected_key key;

        if (kbuf.dsize != sizeof(key)) {
                tdb_delete(ttdb, kbuf);
        }

        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_DATA kbuf, TDB_DATA dbuf, void *state)
{
        struct unexpected_key key;
        struct packet_struct *p;

        if (kbuf.dsize != sizeof(key)) {
                return 0;
        }

        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;

        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;
}