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/* Netfilter Driver for IPSec VPN Client
*
* Copyright(c) 2012 Samsung Electronics
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*
* sshencode.h
*
* Encode/decode API.
*
*/
#ifndef SSHENCODE_H
#define SSHENCODE_H
/* Encode object in `datum' into buffer `buf' whose size is `len' bytes.
Return values:
[0,len] number of bytes datums prentation took in the buffer.
]len,inf[ amount of space writing datum would require.
If buf can be extented, this will be done by the driver, and the
encoder function will be called again. If buf can not be extented
(either it is static, or allocating space fails at the driver,
ssh_encode call will return error. */
typedef int (*SshEncodeDatum)(unsigned char *buf, size_t len,
const void *datum);
/* Decode */
typedef int (*SshDecodeDatum)(const unsigned char *buf, size_t len,
void **datum);
/* Decode, which does not alloc new datum to be returned, but assumes that
it gets preallocated datum of correct size in, and fills it up */
typedef int (*SshDecodeDatumNoAlloc)(const unsigned char *buf, size_t len,
void *datum);
/* The packet encoding/decoding functions take a variable number of
arguments, and decode data from a SshBuffer or a character array as
specified by a format. Each element of the format contains a type
specifier, and arguments depending on the type specifier. The list
must end with a SSH_FORMAT_END specifier. */
typedef enum {
/* Specifies a string with uint32-coded length. This has two arguments.
For encoding,
const unsigned char *data
size_t len
For decoding,
unsigned char **data_return
size_t *len_return
When decoding, either or both arguments may be NULL, in which case they
are not stored. The returned data is allocated by ssh_xmalloc, and an
extra nul (\0) character is automatically added at the end to make it
easier to retrieve strings. */
SSH_FORMAT_UINT32_STR, /* Encode const unsigned char *, size_t */
/* Decode unsigned char *, size_t * */
/* This code can only be used while decoding. This specifies string with
uint32-coded length. This has two arguments:
unsigned char **data_return
size_t *len_return
Either argument may be NULL. *data_return is set to point to the data
in the packet, and *len_return is set to the length of the string.
No null character is stored, and the string remains in the original
buffer. This can only be used with ssh_decode_array. */
SSH_FORMAT_UINT32_STR_NOCOPY, /* unsigned char **, size_t */
/* An 32-bit MSB first integer value. */
SSH_FORMAT_UINT32, /* SshUInt32, note that if you encode constant
integer, you still must use (SshUInt32) cast
before it. Also enums must be casted to
SshUInt32 before encoding. */
/* A boolean value. For encoding, this has a single "Boolean" argument.
For decoding, this has a "Boolean *" argument, where the value will
be stored. The argument may be NULL in which case the value is not
stored. */
SSH_FORMAT_BOOLEAN, /* Boolean */
/* Application specific value given as `void *' argument is encoded
using SshEncodeDatum function, or decoded using SshDecodeDatum.
For information about renderers, see their definitions. */
SSH_FORMAT_SPECIAL, /* SshEncodeDatum, void * */
/* SshDecodeDatum, void ** */
/* A single one-byte character. The argument is of type "unsigned int"
when encoding, and of type "unsigned int *" when decoding. The value
may also be NULL when decoding, in which case the value is ignored. */
SSH_FORMAT_CHAR, /* unsigned int */
/* A fixed-length character array, without explicit length. When
encoding, the arguments are
const unsigned char *buf
size_t len
and when decoding,
unsigned char *buf
size_t len
The buffer must be preallocated when decoding; data is simply copied
there. `buf' may also be NULL, in which the value is ignored. */
SSH_FORMAT_DATA, /* char * (fixed length!), size_t */
/* A 64-bit MSB first integer value. For encoding, this has a single
"SshUInt64" argument (the value), and for decoding an
"SshUInt64 *" argument, where the value will be stored. The argument
may be NULL in which case the value is not stored. */
SSH_FORMAT_UINT64, /* SshUInt64 */
/* A 16-bit MSB first integer value. */
SSH_FORMAT_UINT16, /* SshUInt16 */
/* Marks end of the argument list. */
SSH_FORMAT_END = 0x0d0e0a0d
} SshEncodingFormat;
/* Encodes the given data to a given buffer as specified by the
variable-length argument list. If the given buffer cannot hold the
encoded data, 0 is returned and the given buffer is left in
undefined state. */
size_t ssh_encode_array(unsigned char *buf, size_t bufsize,...);
/* Encodes the given data to a given buffer as specified by the
variable-length argument list. If the given buffer cannot hold the
encoded data, 0 is returned and the given buffer is left in
undefined state. */
size_t ssh_encode_array_va(unsigned char *buf, size_t bufsize, va_list ap);
/* Encodes the given data. Returns the length of encoded data in
bytes, and if `buf_return' is non-NULL, it is set to a memory area
allocated by ssh_xmalloc that contains the data. The caller should
free the data when no longer needed. */
size_t ssh_encode_array_alloc(unsigned char **buf_return, ...);
/* Encodes the given data. Returns the length of encoded data in
bytes, and if `buf_return' is non-NULL, it is set to a memory area
allocated by ssh_xmalloc that contains the data. The caller should
free the data when no longer needed. */
size_t ssh_encode_array_alloc_va(unsigned char **buf_return, va_list ap);
/* Decodes data from the given byte array as specified by the
variable-length argument list. If all specified arguments could be
successfully parsed, returns the number of bytes parsed (any
remaining data can be parsed by first skipping this many bytes).
If parsing any element results in an error, this returns 0 (and
frees any already allocated data). Zero is also returned if the
specified length would be exceeded. */
size_t ssh_decode_array(const unsigned char *buf, size_t len, ...);
/* Decodes data from the given byte array as specified by the
variable-length argument list. If all specified arguments could be
successfully parsed, returns the number of bytes parsed (any
remaining data can be parsed by first skipping this many bytes).
If parsing any element results in an error, this returns 0 (and
frees any already allocated data). Zero is also returned if the
specified length would be exceeded. */
size_t ssh_decode_array_va(const unsigned char *buf, size_t len, va_list ap);
#define ssh_xxcode_unsigned_char_ptr(ptr) ((unsigned char *) (ptr))
#define ssh_xxcode_const_unsigned_char_ptr(ptr) ((const unsigned char *) (ptr))
#define ssh_xxcode_size_t(size) ((size_t) (size))
#define ssh_xxcode_uint32(num) ((SshUInt32) (num))
#define ssh_xxcode_uint32_ptr(ptr) ((SshUInt32 *) (ptr))
#define ssh_xxcode_unsigned_int(num) ((unsigned int) num)
#define ssh_xxcode_unsigned_int_ptr(ptr) ((unsigned int *) ptr)
#define ssh_xxcode_unsigned_char_ptr_ptr(ptr) ((unsigned char **) (ptr))
#define ssh_xxcode_size_t_ptr(size) ((size_t *) (size))
#define SSH_ENCODE_UINT32(num) \
SSH_FORMAT_UINT32, \
ssh_xxcode_uint32(num)
#define SSH_DECODE_UINT32(ptr) \
SSH_FORMAT_UINT32, \
ssh_xxcode_uint32_ptr(ptr)
#define SSH_DECODE_UINT32_STR_NOCOPY(ptr,size) \
SSH_FORMAT_UINT32_STR_NOCOPY, \
ssh_xxcode_unsigned_char_ptr_ptr(ptr), \
ssh_xxcode_size_t_ptr(size)
#define SSH_ENCODE_CHAR(num) \
SSH_FORMAT_CHAR, \
ssh_xxcode_unsigned_int(num)
#define SSH_DECODE_CHAR(ptr) \
SSH_FORMAT_CHAR, \
ssh_xxcode_unsigned_int_ptr(ptr)
#define SSH_ENCODE_DATA(ptr,size) \
SSH_FORMAT_DATA, \
ssh_xxcode_const_unsigned_char_ptr(ptr), \
ssh_xxcode_size_t(size)
#define SSH_DECODE_DATA(ptr,size) \
SSH_FORMAT_DATA, \
ssh_xxcode_unsigned_char_ptr(ptr), \
ssh_xxcode_size_t(size)
#endif /* SSHENCODE_H */
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