/* 
   Unix SMB/CIFS implementation.

   SMB2 client transport context management functions

   Copyright (C) Andrew Tridgell 2005
   
   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"
#include "libcli/raw/libcliraw.h"
#include "libcli/smb2/smb2.h"
#include "lib/socket/socket.h"
#include "lib/events/events.h"
#include "lib/stream/packet.h"
#include "include/dlinklist.h"


/*
  an event has happened on the socket
*/
static void smb2_transport_event_handler(struct event_context *ev, 
					 struct fd_event *fde, 
					 uint16_t flags, void *private)
{
	struct smb2_transport *transport = talloc_get_type(private,
							   struct smb2_transport);
	if (flags & EVENT_FD_READ) {
		packet_recv(transport->packet);
		return;
	}
	if (flags & EVENT_FD_WRITE) {
		packet_queue_run(transport->packet);
	}
}

/*
  destroy a transport
 */
static int transport_destructor(void *ptr)
{
	struct smb2_transport *transport = ptr;
	smb2_transport_dead(transport);
	return 0;
}


/*
  handle receive errors
*/
static void smb2_transport_error(void *private, NTSTATUS status)
{
	struct smb2_transport *transport = talloc_get_type(private, 
							   struct smb2_transport);
	smb2_transport_dead(transport);
}

static NTSTATUS smb2_transport_finish_recv(void *private, DATA_BLOB blob);

/*
  create a transport structure based on an established socket
*/
struct smb2_transport *smb2_transport_init(struct smbcli_socket *sock,
					   TALLOC_CTX *parent_ctx)
{
	struct smb2_transport *transport;

	transport = talloc_zero(parent_ctx, struct smb2_transport);
	if (!transport) return NULL;

	transport->socket = talloc_steal(transport, sock);

	/* setup the stream -> packet parser */
	transport->packet = packet_init(transport);
	if (transport->packet == NULL) {
		talloc_free(transport);
		return NULL;
	}
	packet_set_private(transport->packet, transport);
	packet_set_socket(transport->packet, transport->socket->sock);
	packet_set_callback(transport->packet, smb2_transport_finish_recv);
	packet_set_full_request(transport->packet, packet_full_request_nbt);
	packet_set_error_handler(transport->packet, smb2_transport_error);
	packet_set_event_context(transport->packet, transport->socket->event.ctx);
	packet_set_nofree(transport->packet);

	/* take over event handling from the socket layer - it only
	   handles events up until we are connected */
	talloc_free(transport->socket->event.fde);
	transport->socket->event.fde = event_add_fd(transport->socket->event.ctx,
						    transport->socket,
						    socket_get_fd(transport->socket->sock),
						    EVENT_FD_READ,
						    smb2_transport_event_handler,
						    transport);

	packet_set_serialise(transport->packet, transport->socket->event.fde);

	talloc_set_destructor(transport, transport_destructor);

	transport->options.timeout = 30;

	return transport;
}

/*
  mark the transport as dead
*/
void smb2_transport_dead(struct smb2_transport *transport)
{
	smbcli_sock_dead(transport->socket);

	/* kill all pending receives */
	while (transport->pending_recv) {
		struct smb2_request *req = transport->pending_recv;
		req->state = SMB2_REQUEST_ERROR;
		req->status = NT_STATUS_NET_WRITE_FAULT;
		DLIST_REMOVE(transport->pending_recv, req);
		if (req->async.fn) {
			req->async.fn(req);
		}
	}
}

/*
  we have a full request in our receive buffer - match it to a pending request
  and process
 */
static NTSTATUS smb2_transport_finish_recv(void *private, DATA_BLOB blob)
{
	struct smb2_transport *transport = talloc_get_type(private, 
							     struct smb2_transport);
	uint8_t *buffer, *hdr;
	int len;
	struct smb2_request *req;
	uint64_t seqnum;

	buffer = blob.data;
	len = blob.length;

	hdr = buffer+NBT_HDR_SIZE;

	if (len < SMB2_MIN_SIZE) {
		DEBUG(1,("Discarding smb2 reply of size %d\n", len));
		goto error;
	}

	seqnum = BVAL(hdr, SMB2_HDR_SEQNUM);

	/* match the incoming request against the list of pending requests */
	for (req=transport->pending_recv; req; req=req->next) {
		if (req->seqnum == seqnum) break;
	}

	if (!req) {
		DEBUG(1,("Discarding unmatched reply with seqnum 0x%llx op %d\n", 
			 seqnum, SVAL(hdr, SMB2_HDR_OPCODE)));
		goto error;
	}

	/* fill in the 'in' portion of the matching request */
	req->in.buffer = buffer;
	talloc_steal(req, buffer);
	req->in.size = len;
	req->in.allocated = req->in.size;

	req->in.hdr       = hdr;
	req->in.body      = hdr+SMB2_HDR_BODY;
	req->in.body_size = req->in.size - (SMB2_HDR_BODY+NBT_HDR_SIZE);
	req->in.ptr       = req->in.body;
	req->status       = NT_STATUS(IVAL(hdr, SMB2_HDR_STATUS));

	DEBUG(2, ("SMB2 RECV seqnum=0x%llx\n", req->seqnum));
	dump_data(2, req->in.body, req->in.body_size);

	/* if this request has an async handler then call that to
	   notify that the reply has been received. This might destroy
	   the request so it must happen last */
	DLIST_REMOVE(transport->pending_recv, req);
	req->state = SMB2_REQUEST_DONE;
	if (req->async.fn) {
		req->async.fn(req);
	}
	return NT_STATUS_OK;

error:
	if (req) {
		DLIST_REMOVE(transport->pending_recv, req);
		req->state = SMB2_REQUEST_ERROR;
	}
	dump_data(2, blob.data, blob.length);
	data_blob_free(&blob);
	return NT_STATUS_UNSUCCESSFUL;
}

/*
  handle timeouts of individual smb requests
*/
static void smb2_timeout_handler(struct event_context *ev, struct timed_event *te, 
				   struct timeval t, void *private)
{
	struct smb2_request *req = talloc_get_type(private, struct smb2_request);

	if (req->state == SMB2_REQUEST_RECV) {
		DLIST_REMOVE(req->transport->pending_recv, req);
	}
	req->status = NT_STATUS_IO_TIMEOUT;
	req->state = SMB2_REQUEST_ERROR;
	if (req->async.fn) {
		req->async.fn(req);
	}
}


/*
  destroy a request
*/
static int smb2_request_destructor(void *ptr)
{
	struct smb2_request *req = talloc_get_type(ptr, struct smb2_request);
	if (req->state == SMB2_REQUEST_RECV) {
		DLIST_REMOVE(req->transport->pending_recv, req);
	}
	return 0;
}


/*
  put a request into the send queue
*/
void smb2_transport_send(struct smb2_request *req)
{
	DATA_BLOB blob;
	NTSTATUS status;

	_smb_setlen(req->out.buffer, req->out.size - NBT_HDR_SIZE);

	DEBUG(2, ("SMB2 send seqnum=0x%llx\n", req->seqnum));
	dump_data(2, req->out.body, req->out.body_size);

	/* check if the transport is dead */
	if (req->transport->socket->sock == NULL) {
		req->state = SMB2_REQUEST_ERROR;
		req->status = NT_STATUS_NET_WRITE_FAULT;
		return;
	}

	blob = data_blob_const(req->out.buffer, req->out.size);
	status = packet_send(req->transport->packet, blob);
	if (!NT_STATUS_IS_OK(status)) {
		req->state = SMB2_REQUEST_ERROR;
		req->status = status;
		return;
	}

	req->state = SMB2_REQUEST_RECV;
	DLIST_ADD(req->transport->pending_recv, req);

	/* add a timeout */
	if (req->transport->options.timeout) {
		event_add_timed(req->transport->socket->event.ctx, req, 
				timeval_current_ofs(req->transport->options.timeout, 0), 
				smb2_timeout_handler, req);
	}

	talloc_set_destructor(req, smb2_request_destructor);
}