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/*
* Tiny TACACS+ Client Library
* Copyright (C) 2022 David M. Syzdek <david@syzdek.net>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of David M. Syzdek nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAVID M. SYZDEK BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef __TINYTAC_H
#define __TINYTAC_H 1
///////////////
// //
// Headers //
// //
///////////////
#pragma mark - Headers
#include <stddef.h>
#include <inttypes.h>
#include <sys/types.h>
#include <tinytac_plus.h>
//////////////
// //
// Macros //
// //
//////////////
#pragma mark - Macros
// Exports function type
#undef TINYTAC_C_DECLS
#undef TINYTAC_BEGIN_C_DECLS
#undef TINYTAC_END_C_DECLS
#undef _TINYTAC_I
#undef _TINYTAC_F
#undef _TINYTAC_V
#if defined(__cplusplus) || defined(c_plusplus)
# define TINYTAC_C_DECLS "C" ///< exports as C functions
# define TINYTAC_BEGIN_C_DECLS extern "C" { ///< exports as C functions
# define TINYTAC_END_C_DECLS } ///< exports as C functions
#else
# define TINYTAC_C_DECLS /* empty */ ///< exports as C functions
# define TINYTAC_BEGIN_C_DECLS /* empty */ ///< exports as C functions
# define TINYTAC_END_C_DECLS /* empty */ ///< exports as C functions
#endif
#ifdef WIN32
# ifdef _LIB_LIBTINYTAC_H
# define _TINYTAC_I inline
# define _TINYTAC_F extern TINYTAC_C_DECLS __declspec(dllexport) ///< used for library calls
# define _TINYTAC_V extern TINYTAC_C_DECLS __declspec(dllexport) ///< used for library calls
# else
# define _TINYTAC_I extern TINYTAC_C_DECLS __declspec(dllimport) ///< used for library calls
# define _TINYTAC_F extern TINYTAC_C_DECLS __declspec(dllimport) ///< used for library calls
# define _TINYTAC_V extern TINYTAC_C_DECLS __declspec(dllimport) ///< used for library calls
# endif
#else
# ifdef _LIB_LIBTINYTAC_H
# define _TINYTAC_I inline
# define _TINYTAC_F /* empty */ ///< used for library calls
# define _TINYTAC_V extern TINYTAC_C_DECLS ///< used for library calls
# else
# define _TINYTAC_I extern TINYTAC_C_DECLS ///< used for library calls
# define _TINYTAC_F extern TINYTAC_C_DECLS ///< used for library calls
# define _TINYTAC_V extern TINYTAC_C_DECLS ///< used for library calls
# endif
#endif
///////////////////
// //
// Definitions //
// //
///////////////////
#pragma mark - Definitions
// library error codes
#define TTAC_SUCCESS 0x0000 ///< success
#define TTAC_EUNKNOWN 0x0001 ///< unknown error
#define TTAC_ENOMEM 0x0002 ///< out of virtual memory
#define TTAC_EACCES 0x0003 ///< permission denied
#define TTAC_ENOENT 0x0004 ///< no such file or directory
#define TTAC_ESYNTAX 0x0005 ///< invalid or unrecognized syntax
#define TTAC_ENOBUFS 0x0006 ///< no buffer space available
#define TTAC_EEXISTS 0x0007 ///< dictionary object exists
#define TTAC_EINVAL 0x0008 ///< invalid argument
#define TTAC_EOPTION 0x0009 ///< invalid or unknown option
#define TTAC_EOPTVAL 0x000a ///< invalid option value
// library user options
#define TTAC_NOINIT 0x00000001U
#define TTAC_IPV4 0x00000002U
#define TTAC_IPV6 0x00000004U
#define TTAC_IP_UNSPEC (TTAC_IPV4 | TTAC_IPV6)
#define TTAC_SERVER 0x00000080U
#define TTAC_ASCII 0x00000100U ///< allow ASCII authentication
#define TTAC_PAP 0x00000200U ///< allow PAP authentication
#define TTAC_CHAP 0x00000400U ///< allow CHAP authentication
#define TTAC_MSCHAP 0x00000800U ///< allow MSCHAP authentication
#define TTAC_MSCHAPV2 0x00001000U ///< allow MSCHAPv2 authentication
#define TTAC_AUTHEN_TYPES (TTAC_ASCII | TTAC_PAP | TTAC_CHAP | TTAC_MSCHAP | TTAC_MSCHAPV2 )
#define TTAC_NO 0
#define TTAC_YES 1
// library get/set options
#define TTAC_OPT_DEBUG_LEVEL 1
#define TTAC_OPT_DEBUG_IDENT 2
#define TTAC_OPT_DEBUG_SYSLOG 3
#define TTAC_OPT_HOSTS 10
#define TTAC_OPT_KEY 11
#define TTAC_OPT_KEYS 12
#define TTAC_OPT_AUTHEN_ASCII 20
#define TTAC_OPT_AUTHEN_PAP 21
#define TTAC_OPT_AUTHEN_CHAP 22
#define TTAC_OPT_AUTHEN_MSCHAP 23
#define TTAC_OPT_AUTHEN_MSCHAPV2 24
// library debug levels
#define TTAC_DEBUG_NONE 0
#define TTAC_DEBUG_TRACE 0x0000001
#define TTAC_DEBUG_ARGS 0x0000002
#define TTAC_DEBUG_CONNS 0x0000004
#define TTAC_DEBUG_PACKETS 0x0000008
#define TTAC_DEBUG_PARSE 0x0000010
#define TTAC_DEBUG_ANY (~0x00)
// library defaults
#define TTAC_DFLT_DEBUG_IDENT "libtinytac"
#define TTAC_DFLT_DEBUG_LEVEL TTAC_DEBUG_NONE
#define TTAC_DFLT_DEBUG_SYSLOG TTAC_NO
#define TTAC_DFLT_HOSTS "localhost"
#define TTAC_DFLT_SECRETS NULL
#define TTAC_DFLT_OPTS 0
#define TTAC_DFLT_OPTS_NEG 0
//////////////////
// //
// Data Types //
// //
//////////////////
#pragma mark - Data Types
typedef struct _tinytac TinyTac;
typedef struct _tinytac_packet tinytac_pckt_t;
typedef struct _tinytac_authen_start tinytac_authen_start_t;
typedef struct _tinytac_authen_reply tinytac_authen_reply_t;
typedef struct _tinytac_authen_continue tinytac_authen_cont_t;
typedef struct _tinytac_author_request tinytac_author_req_t;
typedef struct _tinytac_author_reply tinytac_author_reply_t;
typedef struct _tinytac_account_request tinytac_acct_req_t;
typedef struct _tinytac_account_reply tinytac_acct_reply_t;
struct _tinytac_packet
{
uint8_t pckt_version; // 4 bits major and 4 bits minor
uint8_t pckt_type;
uint8_t pckt_seq_no;
uint8_t pckt_flags;
uint32_t pckt_session_id;
uint32_t pckt_length;
uint8_t pckt_body[];
};
struct _tinytac_authen_start
{
uint8_t bdy_action;
uint8_t bdy_priv_lvl;
uint8_t bdy_authen_type;
uint8_t bdy_authen_service;
uint8_t bdy_user_len;
uint8_t bdy_port_len;
uint8_t bdy_rem_addr_len;
uint8_t bdy_data_len;
uint8_t bdy_bytes[];
};
struct _tinytac_authen_reply
{
uint8_t bdy_status;
uint8_t bdy_flags;
uint16_t bdy_server_msg_len;
uint16_t bdy_data_len;
uint8_t bdy_bytes[];
};
struct _tinytac_authen_continue
{
uint16_t bdy_user_msg_len;
uint16_t bdy_data_len;
uint8_t bdy_flags;
uint8_t bdy_bytes[];
};
struct _tinytac_author_request
{
uint8_t bdy_authen_method;
uint8_t bdy_priv_lvl;
uint8_t bdy_authen_type;
uint8_t bdy_authen_service;
uint8_t bdy_user_len;
uint8_t bdy_port_len;
uint8_t bdy_rem_addr_len;
uint8_t bdy_arg_cnt;
uint8_t bdy_bytes[];
};
struct _tinytac_author_reply
{
uint8_t bdy_status;
uint8_t bdy_arg_cnt;
uint16_t bdy_server_msg_len;
uint16_t bdy_data_len;
uint8_t bdy_bytes[];
};
struct _tinytac_account_request
{
uint8_t bdy_flags;
uint8_t bdy_authen_method;
uint8_t bdy_priv_lvl;
uint8_t bdy_authen_type;
uint8_t bdy_authen_service;
uint8_t bdy_user_len;
uint8_t bdy_port_len;
uint8_t bdy_rem_addr_len;
uint8_t bdy_arg_cnt;
uint8_t bdy_bytes[];
};
struct _tinytac_account_reply
{
uint16_t bdy_server_msg_len;
uint16_t bdy_data_len;
uint8_t bdy_status;
uint8_t bdy_bytes[];
};
//////////////////
// //
// Prototypes //
// //
//////////////////
#pragma mark - Prototypes
//------------------//
// error prototypes //
//------------------//
#pragma mark error prototypes
_TINYTAC_F char *
tinytac_strerror(
int errnum );
_TINYTAC_F char *
tinytac_strerror_r(
int errnum,
char * strerrbuf,
size_t buflen );
//-------------------//
// memory prototypes //
//-------------------//
#pragma mark memory prototypes
_TINYTAC_F void
tinytac_free(
void * ptr );
_TINYTAC_F int
tinytac_get_option(
TinyTac * tt,
int option,
void * outvalue );
_TINYTAC_F int
tinytac_initialize(
TinyTac ** ttp,
const char * hosts,
const char * key,
unsigned opts );
_TINYTAC_F int
tinytac_set_option(
TinyTac * tt,
int option,
const void * invalue );
//--------------------//
// network prototypes //
//--------------------//
#pragma mark network prototypes
_TINYTAC_F int
tinytac_recv(
int s,
char * key,
tinytac_pckt_t ** pcktp );
_TINYTAC_F int
tinytac_send(
int s,
char * key,
tinytac_pckt_t * pckt );
//---------------------//
// protocol prototypes //
//---------------------//
#pragma mark protocol prototypes
/// prints hexdump of packet to file stream
///
/// @param[in] fs write hexdump to file stream 'fs'
/// @param[in] pckt packet used to generate psuedo-random pad
/// @param[in] prefix string to prepend to each line
void
tinytac_pckt_hexdump(
FILE * fs,
tinytac_pckt_t * pckt,
const char * prefix );
/// generates pseudo-random pad used to obfuscate the packet body
///
/// @param[in] pckt packet used to generate psuedo-random pad
/// @param[in] key shared secret key used to protect the communication
/// @param[in] key_len length of shared secret key
/// @param[in] md5pad_prev previously generated psuedo-random pad (must be 16 bytes)
/// @param[out] md5pad buffer to store generated
///
/// @return Returns 0 on success or -1 on error.
_TINYTAC_F int
tinytac_pckt_md5pad(
tinytac_pckt_t * pckt,
char * key,
size_t key_len,
uint8_t * md5pad_prev,
uint8_t * md5pad );
/// obfuscate or unobfuscate packet using shared secret key
///
/// @param[in] pckt packet used to generate psuedo-random pad
/// @param[in] key shared secret key used to protect the communication
/// @param[in] key_len length of shared secret key
/// @param[in] unencrypted packet should not be obfuscated (TTAC_YES or TTAC_NO)
///
/// @return Returns 0 on success or -1 on error.
_TINYTAC_F int
tinytac_pckt_obfuscate(
tinytac_pckt_t * pckt,
char * key,
size_t key_len,
unsigned unencrypted );
#endif /* end of header */
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