source: branches/samba-3.3.x/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 3 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, see <http://www.gnu.org/licenses/>.

*/

#include "includes.h"

static TDB_CONTEXT *tdbd = NULL;

/* the key type used in the unexpected 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
 erroneously 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;
        uint32_t enc_ip;

        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));

        /* Encode the ip addr and port. */
        enc_ip = ntohl(p->ip.s_addr);
        SIVAL(buf,0,enc_ip);
        SSVAL(buf,4,p->port);

        len = build_packet(&buf[6], sizeof(buf)-6, p) + 6;

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

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

        kbuf.dptr = (uint8_t *)&key;
        kbuf.dsize = sizeof(key);
        dbuf.dptr = (uint8_t *)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);
}

struct receive_unexpected_state {
        struct packet_struct *matched_packet;
        int match_id;
        enum packet_type match_type;
        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 *private_data)
{
        struct receive_unexpected_state *state =
                (struct receive_unexpected_state *)private_data;
        struct unexpected_key key;
        struct in_addr ip;
        uint32_t enc_ip;
        int port;
        struct packet_struct *p;

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

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

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

        if (dbuf.dsize < 6) {
                return 0;
        }

        /* Decode the ip addr and port. */
        enc_ip = IVAL(dbuf.dptr,0);
        ip.s_addr = htonl(enc_ip);
        port = SVAL(dbuf.dptr,4);

        p = parse_packet((char *)&dbuf.dptr[6],
                        dbuf.dsize-6,
                        state->match_type,
                        ip,
                        port);

        if (!p) {
                return 0;
        }

        if ((state->match_type == NMB_PACKET &&
             p->packet.nmb.header.name_trn_id == state->match_id) ||
            (state->match_type == DGRAM_PACKET &&
             match_mailslot_name(p, state->match_name))) {
                state->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;
        struct receive_unexpected_state state;

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

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

        tdb_traverse(tdb2, traverse_match, &state);

        tdb_close(tdb2);

        return state.matched_packet;
}