/*

 * Dropbear - a SSH2 server

 * 

 * Copyright (c) 2002,2003 Matt Johnston

 * All rights reserved.

 * 

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 * 

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE. */

#ifndef DROPBEAR_ALGO_H_

#define DROPBEAR_ALGO_H_

#include "includes.h"

#include "buffer.h"

#define DROPBEAR_MODE_UNUSED 0

#define DROPBEAR_MODE_CBC 1

#define DROPBEAR_MODE_CTR 2

struct Algo_Type {

  const char *name; /* identifying name */

  char val; /* a value for this cipher, or -1 for invalid */

  const void *data; /* algorithm specific data */

  char usable; /* whether we can use this algorithm */

  const void *mode; /* the mode, currently only used for ciphers,

             points to a 'struct dropbear_cipher_mode' */

};

typedef struct Algo_Type algo_type;

/* lists mapping ssh types of algorithms to internal values */

extern algo_type sshkex[];

extern algo_type sigalgs[];

extern algo_type sshciphers[];

extern algo_type sshhashes[];

extern algo_type ssh_compress[];

extern algo_type ssh_delaycompress[];

extern algo_type ssh_nocompress[];

extern const struct dropbear_cipher dropbear_nocipher;

extern const struct dropbear_cipher_mode dropbear_mode_none;

extern const struct dropbear_hash dropbear_nohash;

struct dropbear_cipher {

  const struct ltc_cipher_descriptor *cipherdesc;

  const unsigned long keysize;

  const unsigned char blocksize;

};

struct dropbear_cipher_mode {

  int (*start)(int cipher, const unsigned char *IV, 

      const unsigned char *key, 

      int keylen, int num_rounds, void *cipher_state);

  int (*encrypt)(const unsigned char *pt, unsigned char *ct, 

      unsigned long len, void *cipher_state);

  int (*decrypt)(const unsigned char *ct, unsigned char *pt, 

      unsigned long len, void *cipher_state);

  int (*aead_crypt)(unsigned int seq,

      const unsigned char *in, unsigned char *out,

      unsigned long len, unsigned long taglen,

      void *cipher_state, int direction);

  int (*aead_getlength)(unsigned int seq,

      const unsigned char *in, unsigned int *outlen,

      unsigned long len, void *cipher_state);

  const struct dropbear_hash *aead_mac;

};

struct dropbear_hash {

  const struct ltc_hash_descriptor *hash_desc;

  const unsigned long keysize;

  /* hashsize may be truncated from the size returned by hash_desc,

     eg sha1-96 */

  const unsigned char hashsize;

};

enum dropbear_kex_mode {

#if DROPBEAR_NORMAL_DH

  DROPBEAR_KEX_NORMAL_DH,

#endif

#if DROPBEAR_ECDH

  DROPBEAR_KEX_ECDH,

#endif

#if DROPBEAR_CURVE25519

  DROPBEAR_KEX_CURVE25519,

#endif

};

struct dropbear_kex {

  enum dropbear_kex_mode mode;

  /* "normal" DH KEX */

  const unsigned char *dh_p_bytes;

  const int dh_p_len;

  /* elliptic curve DH KEX */

#if DROPBEAR_ECDH

  const struct dropbear_ecc_curve *ecc_curve;

#else

  const void* dummy;

#endif

  /* both */

  const struct ltc_hash_descriptor *hash_desc;

};

/* Includes all algorithms is useall is set */

void buf_put_algolist_all(buffer * buf, const algo_type localalgos[], int useall);

/* Includes "usable" algorithms */

void buf_put_algolist(buffer * buf, const algo_type localalgos[]);

#define KEXGUESS2_ALGO_NAME "kexguess2@matt.ucc.asn.au"

int buf_has_algo(buffer *buf, const char *algo);

algo_type * first_usable_algo(algo_type algos[]);

algo_type * buf_match_algo(buffer* buf, algo_type localalgos[],

    int kexguess2, int *goodguess);

#if DROPBEAR_USER_ALGO_LIST

int check_user_algos(const char* user_algo_list, algo_type * algos, 

    const char *algo_desc);

char * algolist_string(const algo_type algos[]);

#endif

enum {

  DROPBEAR_COMP_NONE,

  DROPBEAR_COMP_ZLIB,

  DROPBEAR_COMP_ZLIB_DELAY,

};

#endif /* DROPBEAR_ALGO_H_ */