/*
 * Secure eXtended Message Passing framework
 * Secure eXtended Transport layer implementation: (libsxt)
 * - very similar to SSH2/TLS
 * - using already proven and tested crypto algos
 * - better than TLS for message passing
 *
 * General sxt API and structures
 *
 * (c) Alexander Vdolainen 2016 <avdolainen@zoho.com>
 *
 * libsxmp is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * libsxmp 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.";
 *
 */

#ifndef __SXT_SXT_H__
#define __SXT_SXT_H__

#define SXT_AUTH_PASSWORD  (1 << 1)
#define SXT_AUTH_PEERKEY   (1 << 2)
#define SXT_AUTH_PEERHASH  (1 << 3)

#define SXTPROTO_VERSION  1
#define SXTBEER_TYPE      "lager"

typedef struct __sxtlink_type {
  uint64_t unuuid;
  uint8_t unique[16];
  uint8_t state;

  /* sets keys */
  sxtkey_t *pubkey;
  sxtkey_t *privkey;

  /* peer stuff */
  ndbuf_t *loginpass_pair;
  sxtkey_t *peer_pubkey;

  /* socket */
  sxtsocket_t *socket;

  void *priv;
} sxtlink_t;

typedef struct __sxtset_type {
  /* flags for authentification */
  uint8_t auth_types;
  /* timeouts in secs */
  uint32_t session_tm; /* timeout for session i.e. secs to forget about session while socket io error */
  uint32_t session_lt; /* session life time i.e. when session will be closed, 0 if infinite */

  sxtkey_t *pubkey;
  sxtkey_t *privkey;

  /* authentification ops */
  struct {
    int (*auth_loginpass_pair)(sxtlink_t *, void *);
    int (*auth_key_peer)(sxtlink_t *, void *);
  } auth_ops;

  /* options */
  uint64_t hash;
  const char *strctx;

  void *priv;
} sxtset_t;

typedef struct __sxtsession_type {
  uint8_t unique[16];
  uint8_t state;

  sxtlink_t *link;
  sxtset_t *linkset;

  int sxt_version;
  uint64_t peer_swhash;
  sxtsafebuffer_t *peerbeer;

  /* stats */
  uint64_t rcv_pck;
  uint64_t snd_pck;

} sxtsession_t;

int sxt_init(void);

int sxt_finish(void);

int sxt_reseed(void);

/* plain text beer exchange :) */
int sxt_scanbeer(sxtsession_t *, const char *, size_t);

int sxt_genbeer(sxtsession_t *, sxtsafebuffer_t *);

#endif /* __SXT_SXT_H__ */