/*

  silcauth.h 

  Author: Pekka Riikonen <priikone@silcnet.org>

  Copyright (C) 2001 - 2002 Pekka Riikonen

  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; version 2 of the License.

  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.

*/

/****h* silccore/SILC Authentication Interface
 *
 * DESCRIPTION
 *
 * Implementations of the SILC Authentication Payload and authentication
 * routines.  The SILC Authentication Payload is used to deliver 
 * authentication data usually from client to server in purpose of 
 * gaining access to some service.  The Payload and the authentication
 * routines supports both passphrase and public key (signature) based
 * authentication.
 *
 * This interface defines also the SILC Key Agreement Payload that is
 * used by client to agree on key material usually with another client
 * in the network.
 *
 ***/

#ifndef SILCAUTH_H
#define SILCAUTH_H

/****d* silccore/SilcAuthAPI/SilcAuthMethod
 *
 * NAME
 * 
 *    typedef SilcUInt16 SilcAuthMethod;
 *
 * DESCRIPTION
 *
 *    Authentication method type definition, the authentication methods
 *    and the authentication status'.  The status defines are used by
 *    all authentication protocols in the SILC.
 *
 * SOURCE
 */
typedef SilcUInt16 SilcAuthMethod;

#define SILC_AUTH_NONE        0	           /* No authentication */
#define SILC_AUTH_PASSWORD    1		   /* Passphrase authentication */
#define SILC_AUTH_PUBLIC_KEY  2		   /* Public key authentication */

/* Authentication protocol status message (used by all authentication
   protocols in the SILC). */
#define SILC_AUTH_OK          0
#define SILC_AUTH_FAILED      1
/***/

/****s* silccore/SilcAuthAPI/SilcAuthPayload
 *
 * NAME
 * 
 *    typedef struct SilcAuthPayloadStruct *SilcAuthPayload; 
 *
 *
 * DESCRIPTION
 *
 *    This context is the actual Authentication Payload and is allocated
 *    by silc_auth_payload_parse and given as argument usually to all
 *    silc_auth_payload_* functions.  It is freed by silc_auth_payload_free
 *    function.
 *
 ***/
typedef struct SilcAuthPayloadStruct *SilcAuthPayload;

/****f* silccore/SilcAuthAPI/silc_auth_payload_parse
 *
 * SYNOPSIS
 *
 *    SilcAuthPayload silc_auth_payload_parse(const unsigned char *data,
 *                                            SilcUInt32 data_len);
 *
 * DESCRIPTION
 *
 *    Parses and returns Authentication Payload.  The `data' and the
 *    `data_len' are the raw payload buffer.
 *
 ***/
SilcAuthPayload silc_auth_payload_parse(const unsigned char *data,
					SilcUInt32 data_len);

/****f* silccore/SilcAuthAPI/silc_auth_payload_encode
 *
 * SYNOPSIS
 *
 *    SilcBuffer silc_auth_payload_encode(SilcAuthMethod method,
 *                                        const unsigned char *random_data,
 *                                        SilcUInt16 random_len,
 *                                        const unsigned char *auth_data,
 *                                        SilcUInt16 auth_len);
 *
 * DESCRIPTION
 *
 *    Encodes authentication payload into buffer and returns it.
 *    The `random_data' is provided only if doing public key authentication.
 *    The `auth_data' is the actual authentication data.  If the
 *    `method' is SILC_AUTH_PASSWORD the passphase in `auth_data' sent as
 *    argument SHOULD be UTF-8 encoded, if not library will attempt to
 *    encode it.
 *
 ***/
SilcBuffer silc_auth_payload_encode(SilcAuthMethod method,
				    const unsigned char *random_data,
				    SilcUInt16 random_len,
				    const unsigned char *auth_data,
				    SilcUInt16 auth_len);

/****f* silccore/SilcAuthAPI/silc_auth_payload_free
 *
 * SYNOPSIS
 *
 *    void silc_auth_payload_free(SilcAuthPayload payload);
 *
 * DESCRIPTION
 *
 *    Frees authentication payload and all data in it.
 *
 ***/
void silc_auth_payload_free(SilcAuthPayload payload);

/****f* silccore/SilcAuthAPI/silc_auth_get_method
 *
 * SYNOPSIS
 *
 *    SilcAuthMethod silc_auth_get_method(SilcAuthPayload payload);
 *
 * DESCRIPTION
 *
 *    Get authentication method.
 *
 ***/
SilcAuthMethod silc_auth_get_method(SilcAuthPayload payload);

/****f* silccore/SilcAuthAPI/silc_auth_get_data
 *
 * SYNOPSIS
 *
 *    unsigned char *silc_auth_get_data(SilcAuthPayload payload,
 *                                      SilcUInt32 *auth_len);
 *
 * DESCRIPTION
 *
 *    Get the authentication data. The caller must not free the data.  If
 *    the authentication method is passphrase, then the returned string
 *    is UTF-8 encoded passphrase.
 *
 ***/
unsigned char *silc_auth_get_data(SilcAuthPayload payload,
				  SilcUInt32 *auth_len);

/****f* silccore/SilcAuthAPI/silc_auth_public_key_auth_generate
 *
 * SYNOPSIS
 *
 *    SilcBuffer silc_auth_public_key_auth_generate(SilcPublicKey public_key,
 *                                                  SilcPrivateKey private_key,
 *                                                  SilcRng rng,
 *                                                  SilcHash hash,
 *                                                  const void *id, 
 *                                                  SilcIdType type);
 *
 * DESCRIPTION
 *
 *    Generates Authentication Payload with authentication data. This is used
 *    to do public key based authentication. This generates the random data
 *    and the actual authentication data. Returns NULL on error and the
 *    encoded Authentication Payload on success.
 *
 *    The `private_key' is used to sign the payload.  The `public_key', the
 *    and the `id' is encoded in the payload and signed.  If the `rng' is
 *    NULL then global RNG is used, if non-NULL then `rng' is used as
 *    random number generator.  Also random number is encoded in the
 *    payload before signing it with `private_key'.
 *
 ***/
SilcBuffer silc_auth_public_key_auth_generate(SilcPublicKey public_key,
					      SilcPrivateKey private_key,
					      SilcRng rng, SilcHash hash,
					      const void *id, SilcIdType type);

/****f* silccore/SilcAuthAPI/silc_auth_public_key_auth_verify
 *
 * SYNOPSIS
 *
 *    bool silc_auth_public_key_auth_verify(SilcAuthPayload payload,
 *                                          SilcPublicKey public_key, 
 *                                          SilcHash hash,
 *                                          const void *id, SilcIdType type);
 *
 * DESCRIPTION
 *
 *    Verifies the authentication data. Returns TRUE if authentication was
 *    successful.
 *
 ***/
bool silc_auth_public_key_auth_verify(SilcAuthPayload payload,
				      SilcPublicKey public_key, SilcHash hash,
				      const void *id, SilcIdType type);

/****f* silccore/SilcAuthAPI/silc_auth_public_key_auth_verify_data
 *
 * SYNOPSIS
 *
 *    bool silc_auth_public_key_auth_verify_data(const unsigned char *payload,
 *                                               SilcUInt32 payload_len,
 *                                               SilcPublicKey public_key, 
 *                                               SilcHash hash,
 *                                               const void *id, 
 *                                               SilcIdType type);
 *
 * DESCRIPTION
 *
 *    Same as silc_auth_public_key_auth_verify but the payload has not
 *    been parsed yet.  This will parse it.  Returns TRUE if authentication
 *    was successful.
 *
 ***/
bool silc_auth_public_key_auth_verify_data(const unsigned char *payload,
					   SilcUInt32 payload_len,
					   SilcPublicKey public_key, 
					   SilcHash hash,
					   const void *id, SilcIdType type);

/****f* silccore/SilcAuthAPI/silc_auth_verify
 *
 * SYNOPSIS
 *
 *    bool silc_auth_verify(SilcAuthPayload payload, 
 *                          SilcAuthMethod auth_method,
 *                          const void *auth_data, SilcUInt32 auth_data_len, 
 *                          SilcHash hash, const void *id, SilcIdType type);
 *
 * DESCRIPTION
 *
 *    Verifies the authentication data directly from the Authentication 
 *    Payload. Supports all authentication methods. If the authentication
 *    method is passphrase based then the `auth_data' and `auth_data_len'
 *    are the passphrase and its length.  The passphrase MUST be UTF-8
 *    encoded.  If the method is public key authentication then the
 *    `auth_data' is the SilcPublicKey and the `auth_data_len' is ignored.
 *
 ***/
bool silc_auth_verify(SilcAuthPayload payload, SilcAuthMethod auth_method,
		      const void *auth_data, SilcUInt32 auth_data_len, 
		      SilcHash hash, const void *id, SilcIdType type);

/****f* silccore/SilcAuthAPI/silc_auth_verify_data
 *
 * SYNOPSIS
 *
 *    bool silc_auth_verify_data(const unsigned char *payload, 
 *                               SilcUInt32 payload_len,
 *                               SilcAuthMethod auth_method, 
 *                               const void *auth_data,
 *                               SilcUInt32 auth_data_len, SilcHash hash, 
 *                               const void *id, SilcIdType type);
 * 
 * DESCRIPTION
 *
 *    Same as silc_auth_verify but the payload has not been parsed yet.
 *    Verifies the authentication data directly from the Authentication 
 *    Payload. Supports all authentication methods. If the authentication
 *    method is passphrase based then the `auth_data' and `auth_data_len'
 *    are the passphrase and its length.  The passphrase MUST be UTF-8
 *    encoded.  If the method is public key authentication then the
 *    `auth_data' is the SilcPublicKey and the `auth_data_len' is ignored.
 *
 ***/
bool silc_auth_verify_data(const unsigned char *payload, 
			   SilcUInt32 payload_len,
			   SilcAuthMethod auth_method, const void *auth_data,
			   SilcUInt32 auth_data_len, SilcHash hash, 
			   const void *id, SilcIdType type);

/****s* silccore/SilcAuthAPI/SilcKeyAgreementPayload
 *
 * NAME
 * 
 *    typedef struct SilcKeyAgreementPayloadStruct *SilcKeyAgreementPayload;
 *
 * DESCRIPTION
 *
 *    This context is the actual Key Agreement Payload and is allocated
 *    by silc_key_agreement_payload_parse and given as argument usually to all
 *    silc_key_agreement_* functions.  It is freed by the function
 *    silc_key_agreement_payload_free.
 *
 ***/
typedef struct SilcKeyAgreementPayloadStruct *SilcKeyAgreementPayload;

/****f* silccore/SilcAuthAPI/silc_key_agreement_payload_parse
 *
 * SYNOPSIS
 *
 *    SilcKeyAgreementPayload 
 *    silc_key_agreement_payload_parse(const unsigned char *payload,
 *                                     SilcUInt32 payload_len);
 *
 * DESCRIPTION
 *
 *    Parses and returns an allocated Key Agreement payload.
 *
 ***/
SilcKeyAgreementPayload 
silc_key_agreement_payload_parse(const unsigned char *payload,
				 SilcUInt32 payload_len);

/****f* silccore/SilcAuthAPI/silc_key_agreement_payload_encode
 *
 * SYNOPSIS
 *
 *    SilcBuffer silc_key_agreement_payload_encode(char *hostname,
 *                                                 SilcUInt32 port);
 *
 * DESCRIPTION
 *
 *    Encodes the Key Agreement protocol and returns the encoded buffer
 *
 ***/
SilcBuffer silc_key_agreement_payload_encode(const char *hostname,
					     SilcUInt32 port);

/****f* silccore/SilcAuthAPI/silc_key_agreement_payload_free
 *
 * SYNOPSIS
 *
 *    void silc_key_agreement_payload_free(SilcKeyAgreementPayload payload);
 *
 * DESCRIPTION
 *
 *    Frees the Key Agreement protocol and all data in it.
 *
 ***/
void silc_key_agreement_payload_free(SilcKeyAgreementPayload payload);

/****f* silccore/SilcAuthAPI/silc_key_agreement_get_hostname
 *
 * SYNOPSIS
 *
 *    char *silc_key_agreement_get_hostname(SilcKeyAgreementPayload payload);
 *
 * DESCRIPTION
 *
 *    Returns the hostname in the payload. Caller must not free it.
 *    The hostname is the host that is able to accept key negotiation
 *    using the SILC Key Exchange protocol.
 *
 ***/
char *silc_key_agreement_get_hostname(SilcKeyAgreementPayload payload);

/****f* silccore/SilcAuthAPI/silc_key_agreement_get_port
 *
 * SYNOPSIS
 *
 *    SilcUInt32 silc_key_agreement_get_port(SilcKeyAgreementPayload payload);
 *
 * DESCRIPTION
 *
 *    Returns the port in the payload.  The port is the port on the
 *    host returned by silc_key_agreement_get_hostname that is running
 *    the SILC Key Exchange protocol.
 *
 ***/
SilcUInt32 silc_key_agreement_get_port(SilcKeyAgreementPayload payload);

#endif
