/*

   Unix SMB/CIFS implementation.

   Infrastructure for async SMB client requests

   Copyright (C) Volker Lendecke 2008

   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"

#include "system/network.h"

#include "lib/async_req/async_sock.h"

#include "read_smb.h"

#include "lib/util/tevent_unix.h"

#include "libcli/smb/smb_constants.h"

/*

 * Read an smb packet asynchronously, discard keepalives

 */

struct read_smb_state {

  struct tevent_context *ev;

  int fd;

  uint8_t *buf;

};

static void read_smb_done(struct tevent_req *subreq);

struct tevent_req *read_smb_send(TALLOC_CTX *mem_ctx,

         struct tevent_context *ev,

         int fd)

{

  struct tevent_req *result, *subreq;

  struct read_smb_state *state;

  result = tevent_req_create(mem_ctx, &state, struct read_smb_state);

  if (result == NULL) {

    return NULL;

  }

  state->ev = ev;

  state->fd = fd;

  subreq = read_packet_send(state, ev, fd, 4, read_smb_more, NULL);

  if (subreq == NULL) {

    goto fail;

  }

  tevent_req_set_callback(subreq, read_smb_done, result);

  return result;

 fail:

  TALLOC_FREE(result);

  return NULL;

}

ssize_t read_smb_more(uint8_t *buf, size_t buflen, void *private_data)

{

  if (buflen > 4) {

    return 0; /* We've been here, we're done */

  }

  return smb_len_tcp(buf);

}

static void read_smb_done(struct tevent_req *subreq)

{

  struct tevent_req *req = tevent_req_callback_data(

    subreq, struct tevent_req);

  struct read_smb_state *state = tevent_req_data(

    req, struct read_smb_state);

  ssize_t len;

  int err;

  len = read_packet_recv(subreq, state, &state->buf, &err);

  TALLOC_FREE(subreq);

  if (len == -1) {

    tevent_req_error(req, err);

    return;

  }

  if (CVAL(state->buf, 0) == NBSSkeepalive) {

    subreq = read_packet_send(state, state->ev, state->fd, 4,

            read_smb_more, NULL);

    if (tevent_req_nomem(subreq, req)) {

      return;

    }

    tevent_req_set_callback(subreq, read_smb_done, req);

    return;

  }

  tevent_req_done(req);

}

ssize_t read_smb_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,

          uint8_t **pbuf, int *perrno)

{

  struct read_smb_state *state = tevent_req_data(

    req, struct read_smb_state);

  if (tevent_req_is_unix_error(req, perrno)) {

    tevent_req_received(req);

    return -1;

  }

  *pbuf = talloc_move(mem_ctx, &state->buf);

  tevent_req_received(req);

  return talloc_get_size(*pbuf);

}