ROHC CRC routines. More...

#include "crc.h"
#include "protocols/ip_numbers.h"
#include "protocols/udp.h"
#include "protocols/rtp.h"
#include "protocols/esp.h"
#include "protocols/tcp.h"
#include <stdlib.h>
#include <assert.h>

Include dependency graph for crc.c:

Functions
static uint8_t	ipv6_ext_calc_crc_static (const uint8_t const ip, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-STATIC part of IPv6 extensions.
static uint8_t	ipv6_ext_calc_crc_dyn (const uint8_t const ip, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-DYNAMIC part of IPv6 extensions.
static uint8_t *	ipv6_get_first_extension (const uint8_t const ip, uint8_t const type)
	Get the first extension in an IPv6 packet.
static bool	rohc_crc_get_polynom (const rohc_crc_type_t crc_type, uint8_t *const polynom)
	Get the polynom for the given CRC type.
static uint8_t	crc_calc_8 (const uint8_t const buf, const size_t size, const uint8_t init_val, const uint8_t const crc_table)
	Optimized CRC-8 calculation using a table.
static uint8_t	crc_calc_7 (const uint8_t const buf, const size_t size, const uint8_t init_val, const uint8_t const crc_table)
	Optimized CRC-7 calculation using a table.
static uint8_t	crc_calc_3 (const uint8_t const buf, const size_t size, const uint8_t init_val, const uint8_t const crc_table)
	Optimized CRC-3 calculation using a table.
int	crc_get_polynom (int type)
	Get the polynom for the given CRC type.
void	crc_init_table (unsigned char *table, unsigned char poly)
	Initialize a CRC table given a 256-byte table and the polynom to use.
bool	rohc_crc_init_table (uint8_t *const table, const rohc_crc_type_t crc_type)
	Initialize a CRC table given a 256-byte table and the CRC type to use.
uint8_t	crc_calculate (const rohc_crc_type_t crc_type, const uint8_t const data, const size_t length, const uint8_t init_val, const uint8_t const crc_table)
	Calculate the checksum for the given data.
uint32_t	crc_calc_fcs32 (const uint8_t *const data, const size_t length, const uint32_t init_val)
	Optimized CRC FCS-32 calculation using a table.
uint8_t	compute_crc_static (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-STATIC part of an IP header.
uint8_t	compute_crc_dynamic (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-DYNAMIC part of an IP header.
uint8_t	udp_compute_crc_static (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-STATIC part of an UDP or UDP-Lite header.
uint8_t	udp_compute_crc_dynamic (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-DYNAMIC part of an UDP or UDP-Lite header.
uint8_t	esp_compute_crc_static (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-STATIC part of an ESP header.
uint8_t	esp_compute_crc_dynamic (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-DYNAMIC part of an ESP header.
uint8_t	rtp_compute_crc_static (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-STATIC part of a RTP header.
uint8_t	rtp_compute_crc_dynamic (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-DYNAMIC part of a RTP header.
uint8_t	tcp_compute_crc_static (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-STATIC part of an TCP header.
uint8_t	tcp_compute_crc_dynamic (const uint8_t const ip, const uint8_t const ip2, const uint8_t const next_header, const rohc_crc_type_t crc_type, const uint8_t init_val, const uint8_t const crc_table)
	Compute the CRC-DYNAMIC part of an TCP header.
Variables
unsigned char	crc_table_8 [256]
unsigned char	crc_table_7 [256]
unsigned char	crc_table_6 [256]
unsigned char	crc_table_3 [256]
unsigned char	crc_table_2 [256]
static const uint32_t	crc_table_fcs32 [256]
	The pre-computed table for 32-bit Frame Check Sequence (FCS)

Detailed Description

ROHC CRC routines.

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

Function Documentation

uint8_t compute_crc_dynamic	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-DYNAMIC part of an IP header.

Concerned fields are:

bytes 3-4, 5-6, 11-12 in original IPv4 header
bytes 5-6 in original IPv6 header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t compute_crc_static	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-STATIC part of an IP header.

Concerned fields are: all fields expect those for CRC-DYNAMIC

bytes 1-2, 7-10, 13-20 in original IPv4 header
bytes 1-4, 7-40 in original IPv6 header

This function is one of the functions that must exist in one profile for the framework to work.

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

static uint8_t crc_calc_3	(	const uint8_t *const	buf,
		const size_t	size,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)		`[inline, static]`

Optimized CRC-3 calculation using a table.

Parameters:

buf	The data to compute the CRC for
size	The size of the data
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The CRC byte

static uint8_t crc_calc_7	(	const uint8_t *const	buf,
		const size_t	size,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)		`[inline, static]`

Optimized CRC-7 calculation using a table.

Parameters:

buf	The data to compute the CRC for
size	The size of the data
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The CRC byte

static uint8_t crc_calc_8	(	const uint8_t *const	buf,
		const size_t	size,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)		`[inline, static]`

Optimized CRC-8 calculation using a table.

Parameters:

buf	The data to compute the CRC for
size	The size of the data
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The CRC byte

uint32_t crc_calc_fcs32	(	const uint8_t *const	data,
		const size_t	length,
		const uint32_t	init_val
	)

Optimized CRC FCS-32 calculation using a table.

Parameters:

data	The data to compute the CRC for
length	The size of the data
init_val	The initial value of the CRC

Returns:: The 32-bit CRC

uint8_t crc_calculate	(	const rohc_crc_type_t	crc_type,
		const uint8_t *const	data,
		const size_t	length,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Calculate the checksum for the given data.

Parameters:

crc_type	The CRC type
data	The data to calculate the checksum on
length	The length of the data
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t esp_compute_crc_dynamic	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-DYNAMIC part of an ESP header.

Concerned fields are:

bytes 5-8 in original ESP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t esp_compute_crc_static	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-STATIC part of an ESP header.

Concerned fields are: all fields expect those for CRC-DYNAMIC

bytes 1-4 in original ESP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

static uint8_t ipv6_ext_calc_crc_dyn	(	const uint8_t *const	ip,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)		`[static]`

Compute the CRC-DYNAMIC part of IPv6 extensions.

Only entire AH header is concerned.

Parameters:

ip	The IPv6 packet
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

static uint8_t ipv6_ext_calc_crc_static	(	const uint8_t *const	ip,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)		`[static]`

Compute the CRC-STATIC part of IPv6 extensions.

Prototypes of private functions

Private functions All extensions are concerned except entire AH header.

Parameters:

ip	The IPv6 packet
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

static uint8_t * ipv6_get_first_extension	(	const uint8_t *const	ip,
		uint8_t *const	type
	)		`[static]`

Get the first extension in an IPv6 packet.

Parameters:

ip	The IPv6 packet
type	The type of the extension

Returns:: The extension, NULL if there is no extension

static bool rohc_crc_get_polynom	(	const rohc_crc_type_t	crc_type,
		uint8_t *const	polynom
	)		`[static]`

Get the polynom for the given CRC type.

Parameters:

crc_type	The CRC type
polynom	IN/OUT: the polynom for the requested CRC type

Returns:: true in case of success, false otherwise

bool rohc_crc_init_table	(	uint8_t *const	table,
		const rohc_crc_type_t	crc_type
	)

Initialize a CRC table given a 256-byte table and the CRC type to use.

Parameters:

table	IN/OUT: The 256-byte table to initialize
crc_type	The type of CRC to initialize the table for

Returns:: true in case of success, false in case of failure

uint8_t rtp_compute_crc_dynamic	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-DYNAMIC part of a RTP header.

Concerned fields are:

bytes 2, 3-4, 5-8 in original RTP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t rtp_compute_crc_static	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-STATIC part of a RTP header.

Concerned fields are: all fields expect those for CRC-DYNAMIC

bytes 1, 9-12 (and CSRC list) in original RTP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t tcp_compute_crc_dynamic	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-DYNAMIC part of an TCP header.

Concerned fields are:

bytes 5-20 in original TCP header
TCP options

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t tcp_compute_crc_static	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-STATIC part of an TCP header.

Concerned fields are: all fields expect those for CRC-DYNAMIC

bytes 1-4 in original TCP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t udp_compute_crc_dynamic	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-DYNAMIC part of an UDP or UDP-Lite header.

Concerned fields are:

bytes 5-6, 7-8 in original UDP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

uint8_t udp_compute_crc_static	(	const uint8_t *const	ip,
		const uint8_t *const	ip2,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

Compute the CRC-STATIC part of an UDP or UDP-Lite header.

Concerned fields are: all fields expect those for CRC-DYNAMIC

bytes 1-4 in original UDP header

Parameters:

ip	The outer IP packet
ip2	The inner IP packet if there is 2 IP headers, NULL otherwise
next_header	The next header located after the IP header(s)
crc_type	The type of CRC
init_val	The initial CRC value
crc_table	The pre-computed table for fast CRC computation

Returns:: The checksum

Variable Documentation

unsigned char crc_table_2[256]

The table to enable fast CRC-2 computation

Deprecated:: please do not use this variable anymore

unsigned char crc_table_3[256]

The table to enable fast CRC-3 computation

Deprecated:: please do not use this variable anymore

unsigned char crc_table_6[256]

The table to enable fast CRC-6 computation

Deprecated:: please do not use this variable anymore

unsigned char crc_table_7[256]

The table to enable fast CRC-7 computation

Deprecated:: please do not use this variable anymore

unsigned char crc_table_8[256]

The table to enable fast CRC-8 computation

Deprecated:: please do not use this variable anymore

const uint32_t crc_table_fcs32[256] [static]

The pre-computed table for 32-bit Frame Check Sequence (FCS)

x**0 + x**1 + x**2 + x**4 + x**5 + x**7 + x**8 + x**10 + x**11 + x**12 + x**16 + x**22 + x**23 + x**26 + x**32

Copied from RFC 1662, appendix C.3

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation