/*
   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 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;
	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;

	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;

	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 ((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;
}