Library of decoding methods from RFC4997 and RFC4996. More...

#include "rfc4996.h"
#include "rohc_bit_ops.h"
#include "rohc_traces_internal.h"
#include "rohc_decomp_internals.h"
#include "rohc_debug.h"
#include "rohc_utils.h"
#include "crc.h"
#include "protocols/tcp.h"
#include "rohc_packets.h"
#include "rohc_decomp.h"
#include <string.h>
#include <assert.h>

Include dependency graph for decomp/schemes/rfc4996.c:

Functions
uint32_t	d_lsb (const struct rohc_decomp_ctxt *const context, int num_lsbs_param, int offset_param, unsigned int context_value, unsigned int value)
	Decompress the lower bits from the given value and the context value.
int	d_static_or_irreg8 (const uint8_t rohc_data, const uint8_t context_value, const int indicator, uint8_t const decoded_value)
	Decompress the 8-bit given value, according to the indicator.
int	d_static_or_irreg16 (const uint8_t rohc_data, const uint16_t context_value, const int indicator, uint16_t const decoded_value)
	Decompress the 16-bit given value, according to the indicator.
int	variable_length_32_dec (const struct rohc_lsb_decode const lsb, const struct rohc_decomp_ctxt const context, const uint8_t rohc_data, const int indicator, uint32_t const decoded_value)
	Decode the 32 bits value, according to the indicator.
int	d_optional32 (const int flag, const uint8_t const data, const size_t data_len, uint32_t context_value, uint32_t const decoded_value)
	Decode the 32 bits value, according to the indicator.
uint32_t	d_field_scaling (const uint32_t scaling_factor, const uint32_t scaled_value, const uint32_t residue_field)
	Calculate the value from the scaling factor, scaled value and residue.
unsigned int	rsf_index_dec (unsigned int rsf_index)
	Calculate the rsf flags from the rsf index.
static uint32_t	d_c_lsb (const struct rohc_decomp_ctxt *const context, int num_lsbs_param, unsigned int offset_param, unsigned int context_value, unsigned int original_value)
	Compress the lower bits of the given value.
uint16_t	d_ip_id_lsb (const struct rohc_decomp_ctxt *const context, const int behavior, const unsigned int k, const unsigned int p, const uint16_t context_ip_id, const uint16_t value, const uint16_t msn)
	Decompress the lower bits of IP-ID.
int	d_optional_ip_id_lsb (const struct rohc_decomp_ctxt const context, const uint8_t const rohc_data, const int behavior, const int indicator, const uint16_t context_ip_id, uint16_t *const ip_id, const uint16_t msn)
	Decompress the IP-ID.
int	dscp_decode (const uint8_t const rohc_data, const uint8_t context_value, const int indicator, uint8_t const decoded_value)
	Decode the DSCP field.
Variables
static unsigned int	lsb_masks []
	Table of the mask for lsb()
unsigned int	lsb_xor_masks []
	Table of the mask for lsb()
unsigned int	variable_length_32_size [4]
	Table of the size of the variable_length_32 encode value.

Detailed Description

Library of decoding methods from RFC4997 and RFC4996.

Author:: FWX <rohc_team@dialine.fr>; Didier Barvaux <didier@barvaux.org>

Function Documentation

static uint32_t d_c_lsb	(	const struct rohc_decomp_ctxt *const	context,
		int	num_lsbs_param,
		unsigned int	offset_param,
		unsigned int	context_value,
		unsigned int	original_value
	)		`[static]`

Compress the lower bits of the given value.

See RFC4997 page 27

Parameters:

context	The compressor context
num_lsbs_param	The number of bits
offset_param	The offset
context_value	The value of the context
original_value	The value to compress

Returns:: The compressed value with num_lsbs_param bits

Todo:: TODO: duplicated code from rfc4996_encoding.c

uint32_t d_field_scaling	(	const uint32_t	scaling_factor,
		const uint32_t	scaled_value,
		const uint32_t	residue_field
	)

Calculate the value from the scaling factor, scaled value and residue.

See RFC4996 page 49

Parameters:

scaling_factor	The scaling factor
scaled_value	The scaled value
residue_field	The residue value

Returns:: The unscaled value

uint16_t d_ip_id_lsb	(	const struct rohc_decomp_ctxt *const	context,
		const int	behavior,
		const unsigned int	k,
		const unsigned int	p,
		const uint16_t	context_ip_id,
		const uint16_t	value,
		const uint16_t	msn
	)

Decompress the lower bits of IP-ID.

See RFC4996 page 75

Parameters:

context	The decompression context
behavior	The IP-ID behavior
k	The num_lsbs_param parameter for d_lsb()
p	The offset parameter for d_lsb()
context_ip_id	The context IP-ID value
value	The value to decompress
msn	The Master Sequence Number

Returns:: The IP-ID

uint32_t d_lsb	(	const struct rohc_decomp_ctxt *const	context,
		int	num_lsbs_param,
		int	offset_param,
		unsigned int	context_value,
		unsigned int	value
	)

Decompress the lower bits from the given value and the context value.

See RFC4997 page 27

Parameters:

context	The decompression context
num_lsbs_param	The number of bits
offset_param	The offset
context_value	The value of the context
value	The compressed value

Returns:: The uncompressed value

int d_optional32	(	const int	flag,
		const uint8_t *const	data,
		const size_t	data_len,
		uint32_t	context_value,
		uint32_t *const	decoded_value
	)

Decode the 32 bits value, according to the indicator.

See RFC4996 page 47

Parameters:

	flag	Flag of compression
	data	The remaining part of the ROHC packet
	data_len	The length of the remaining part of the packet
	context_value	The context value
[out]	decoded_value	The uncompressed value

Returns:: The number of ROHC bytes parsed, -1 if packet is malformed

int d_optional_ip_id_lsb	(	const struct rohc_decomp_ctxt *const	context,
		const uint8_t *const	rohc_data,
		const int	behavior,
		const int	indicator,
		const uint16_t	context_ip_id,
		uint16_t *const	ip_id,
		const uint16_t	msn
	)

Decompress the IP-ID.

See RFC4996 page 76

Parameters:

context	The decompression context
rohc_data	The compressed value
behavior	The IP-ID behavior
indicator	The compression indicator
context_ip_id	The context IP-ID value
ip_id	Pointer to the uncompressed IP-ID
msn	The Master Sequence Number

Returns:: The length (in bytes) of the compressed value, -1 if ROHC data is malformed

int d_static_or_irreg16	(	const uint8_t *	rohc_data,
		const uint16_t	context_value,
		const int	indicator,
		uint16_t *const	decoded_value
	)

Decompress the 16-bit given value, according to the indicator.

Parameters:

	rohc_data	The packet value
	context_value	The context value
	indicator	The indicator of compression
[out]	decoded_value	The decoded value

Returns:: The length (in bytes) of the compressed value, -1 if ROHC data is malformed

int d_static_or_irreg8	(	const uint8_t *	rohc_data,
		const uint8_t	context_value,
		const int	indicator,
		uint8_t *const	decoded_value
	)

Decompress the 8-bit given value, according to the indicator.

Parameters:

	rohc_data	The packet value
	context_value	The context value
	indicator	The indicator of compression
[out]	decoded_value	The decoded value

Returns:: The length (in bytes) of the compressed value, -1 if ROHC data is malformed

int dscp_decode	(	const uint8_t *const	rohc_data,
		const uint8_t	context_value,
		const int	indicator,
		uint8_t *const	decoded_value
	)

Decode the DSCP field.

Parameters:

	rohc_data	The compressed value
	context_value	The context DSCP value
	indicator	The indicator of the compression
[out]	decoded_value	The decoded value

Returns:: The length (in bytes) of the compressed value, -1 if ROHC data is malformed

unsigned int rsf_index_dec ( unsigned int rsf_index )

Calculate the rsf flags from the rsf index.

See RFC4996 page 71

Parameters:

rsf_index The rsf index

Returns:: The rsf flags

int variable_length_32_dec	(	const struct rohc_lsb_decode *const	lsb,
		const struct rohc_decomp_ctxt *const	context,
		const uint8_t *	rohc_data,
		const int	indicator,
		uint32_t *const	decoded_value
	)

Decode the 32 bits value, according to the indicator.

See RFC4996 page 46

Parameters:

	lsb	The WLSB decoding context
	context	The decompression context
	rohc_data	The compressed value
	indicator	The indicator of compression
[out]	decoded_value	The decoded value (in NBO)

Returns:: The length (in bytes) of the compressed value, -1 if ROHC data is malformed

Variable Documentation

unsigned int lsb_masks[] [static]

Initial value:

{
        0x00000,
        0x00001, 0x00003, 0x00007, 0x0000F,
        0x0001F, 0x0003F, 0x0007F, 0x000FF,
        0x001FF, 0x003FF, 0x007FF, 0x00FFF,
        0x01FFF, 0x03FFF, 0x07FFF, 0x0FFFF,
        0x1FFFF, 0x3FFFF, 0x7FFFF, 0xFFFFF
}

Table of the mask for lsb()

unsigned int lsb_xor_masks[]

Initial value:

{
        0xFFFFFFFF,
        0xFFFFFFFE, 0xFFFFFFFC, 0xFFFFFFF8, 0xFFFFFFF0,
        0xFFFFFFE0, 0xFFFFFFC0, 0xFFFFFF80, 0xFFFFFF00,
        0xFFFFFE00, 0xFFFFFC00, 0xFFFFF800, 0xFFFFF000,
        0xFFFFE000, 0xFFFFC000, 0xFFFF8000, 0xFFFF0000,
        0xFFFE0000, 0xFFFC0000, 0xFFF80000, 0xFFF00000
}

Table of the mask for lsb()

unsigned int variable_length_32_size[4]

Initial value:

{
        0,1,2,4
}

Table of the size of the variable_length_32 encode value.

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation