ROHC CRC routines. More...

#include "ip.h"
#include "protocols/udp.h"
#include "protocols/rtp.h"
#include "protocols/esp.h"
#include "protocols/tcp.h"
#include <rohc/rohc.h>
#include <stdbool.h>

Include dependency graph for crc.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	CRC_INIT_3 0x7
	The CRC-3 initial value. More...

#define	CRC_INIT_7 0x7f
	The CRC-7 initial value. More...

#define	CRC_INIT_8 0xff
	The CRC-8 initial value. More...

#define	CRC_INIT_FCS32 0xffffffff

#define	CRC_FCS32_LEN 4U

Enumerations
enum	rohc_crc_type_t { ROHC_CRC_TYPE_NONE = 0, ROHC_CRC_TYPE_3 = 3, ROHC_CRC_TYPE_7 = 7, ROHC_CRC_TYPE_8 = 8 }

Functions
void	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. More...

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. More...

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. More...

uint8_t	compute_crc_static (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

uint8_t	compute_crc_dynamic (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

static uint8_t	udp_compute_crc_static (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

static uint8_t	udp_compute_crc_dynamic (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

static uint8_t	esp_compute_crc_static (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

static uint8_t	esp_compute_crc_dynamic (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

static uint8_t	rtp_compute_crc_static (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

static uint8_t	rtp_compute_crc_dynamic (const uint8_t const outer_ip, const uint8_t const inner_ip, 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. More...

uint8_t	compute_crc_ctrl_fields (const rohc_profile_t profile_id, const uint8_t *const crc_table, const uint8_t reorder_ratio, const uint16_t msn, const uint8_t ip_id_behaviors[], const size_t ip_id_behaviors_nr)
	Compute the CRC-3 over control fields for ROHCv2 profiles. More...

Detailed Description

ROHC CRC routines.

Author: Didier Barvaux didie.nosp@m.r.ba.nosp@m.rvaux.nosp@m.@tou.nosp@m.louse.nosp@m..viv.nosp@m.eris..nosp@m.com; Didier Barvaux didie.nosp@m.r@ba.nosp@m.rvaux.nosp@m..org; FWX rohc_.nosp@m.team.nosp@m.@dial.nosp@m.ine..nosp@m.fr

Macro Definition Documentation

◆ CRC_FCS32_LEN

#define CRC_FCS32_LEN 4U

The length (in bytes) of the FCS-32 CRC

◆ CRC_INIT_3

#define CRC_INIT_3 0x7

The CRC-3 initial value.

◆ CRC_INIT_7

#define CRC_INIT_7 0x7f

The CRC-7 initial value.

◆ CRC_INIT_8

#define CRC_INIT_8 0xff

The CRC-8 initial value.

◆ CRC_INIT_FCS32

#define CRC_INIT_FCS32 0xffffffff

The FCS-32 initial value

Enumeration Type Documentation

◆ rohc_crc_type_t

enum rohc_crc_type_t

The different types of CRC used to protect ROHC headers

Enumerator
ROHC_CRC_TYPE_NONE	No CRC selected
ROHC_CRC_TYPE_3	The CRC-3 type
ROHC_CRC_TYPE_7	The CRC-7 type
ROHC_CRC_TYPE_8	The CRC-8 type

Function Documentation

◆ compute_crc_ctrl_fields()

uint8_t compute_crc_ctrl_fields	(	const rohc_profile_t	profile_id,
		const uint8_t *const	crc_table,
		const uint8_t	reorder_ratio,
		const uint16_t	msn,
		const uint8_t	ip_id_behaviors[],
		const size_t	ip_id_behaviors_nr
	)

Compute the CRC-3 over control fields for ROHCv2 profiles.

Parameters

profile_id	The current profile ID
crc_table	The pre-computed table for fast CRC computation
reorder_ratio	The 2-bit reorder_ratio control field, padded with 6 MSB of zeroes
msn	The 16-bit MSN control field
ip_id_behaviors	The 2-bit control fields behavior of IP-ID, one per IP header, all are padded with 6 MSB of zeroes
ip_id_behaviors_nr	The number of IP headers, ie. the number of IP-ID behavior control fields to compute the CRC over

Returns: The computed CRC-3

◆ compute_crc_dynamic()

uint8_t compute_crc_dynamic	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		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

outer_ip	The outer IP packet
inner_ip	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

◆ compute_crc_static()

uint8_t compute_crc_static	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		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

outer_ip	The outer IP packet
inner_ip	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

◆ crc_calc_fcs32()

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

◆ crc_calculate()

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

◆ esp_compute_crc_dynamic()

static uint8_t esp_compute_crc_dynamic	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

inlinestatic

Compute the CRC-DYNAMIC part of an ESP header.

Concerned fields are:

bytes 5-8 in original ESP header

Parameters

outer_ip	The outer IP packet
inner_ip	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

◆ esp_compute_crc_static()

static uint8_t esp_compute_crc_static	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

inlinestatic

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

outer_ip	The outer IP packet
inner_ip	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

◆ rohc_crc_init_table()

void 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.

Public functions

Parameters

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

◆ rtp_compute_crc_dynamic()

static uint8_t rtp_compute_crc_dynamic	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

inlinestatic

Compute the CRC-DYNAMIC part of a RTP header.

Concerned fields are:

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

Parameters

outer_ip	The outer IP packet
inner_ip	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

◆ rtp_compute_crc_static()

static uint8_t rtp_compute_crc_static	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

inlinestatic

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

outer_ip	The outer IP packet
inner_ip	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

◆ udp_compute_crc_dynamic()

static uint8_t udp_compute_crc_dynamic	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

inlinestatic

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

outer_ip	The outer IP packet
inner_ip	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

◆ udp_compute_crc_static()

static uint8_t udp_compute_crc_static	(	const uint8_t *const	outer_ip,
		const uint8_t *const	inner_ip,
		const uint8_t *const	next_header,
		const rohc_crc_type_t	crc_type,
		const uint8_t	init_val,
		const uint8_t *const	crc_table
	)

inlinestatic

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

outer_ip	The outer IP packet
inner_ip	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

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ CRC_FCS32_LEN

◆ CRC_INIT_3

◆ CRC_INIT_7

◆ CRC_INIT_8

◆ CRC_INIT_FCS32

Enumeration Type Documentation

◆ rohc_crc_type_t

Function Documentation

◆ compute_crc_ctrl_fields()

◆ compute_crc_dynamic()

◆ compute_crc_static()

◆ crc_calc_fcs32()

◆ crc_calculate()

◆ esp_compute_crc_dynamic()

◆ esp_compute_crc_static()

◆ rohc_crc_init_table()

◆ rtp_compute_crc_dynamic()

◆ rtp_compute_crc_static()

◆ udp_compute_crc_dynamic()

◆ udp_compute_crc_static()