ROHC generic decompression context for IP-only, UDP and UDP Lite profiles. More...

#include "rohc_decomp.h"
#include "rohc_packets.h"
#include "comp_list.h"
#include "lsb.h"
#include "ip_id.h"
#include "ip.h"
#include <stddef.h>
#include <stdbool.h>

Include dependency graph for d_generic.h:

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Go to the source code of this file.

Data Structures
struct	d_generic_changes
	Store information about an IP header between the different decompressions of IP packets. More...
struct	d_generic_context
	The generic decompression context. More...
struct	list_decomp
	The list decompressor. More...
Defines
#define	MAX_ITEM 15
#define	LIST_COMP_WINDOW 100
#define	L 5
Functions
void *	d_generic_create (void)
	Create the generic decompression context.
void	d_generic_destroy (void *context)
	Destroy the context.
int	d_generic_decode (struct rohc_decomp decomp, struct d_context context, const unsigned char const rohc_packet, const unsigned int rohc_length, int second_byte, unsigned char dest)
	Decode one IR-DYN, UO-0, UO-1 or UOR-2 packet, but not IR packet.
int	d_generic_decode_ir (struct rohc_decomp decomp, struct d_context context, const unsigned char const rohc_packet, const unsigned int rohc_length, int large_cid_len, int is_addcid_used, unsigned char dest)
	Decode one IR packet.
unsigned int	d_generic_detect_ir_size (struct d_context context, unsigned char packet, unsigned int plen, unsigned int large_cid_len)
	Find the length of the IR header.
unsigned int	d_generic_detect_ir_dyn_size (struct d_context context, unsigned char first_byte, unsigned int plen, unsigned int large_cid_len)
	Find the length of the IR-DYN header.
int	d_generic_get_sn (struct d_context *context)
	Get the reference SN value of the context.
rohc_packet_t	find_packet_type (struct rohc_decomp decomp, struct d_context context, const unsigned char *packet, const size_t rohc_length, int second_byte)
	Find out of which type is the ROHC packet.

Detailed Description

ROHC generic decompression context for IP-only, UDP and UDP Lite profiles.

Author:: Didier Barvaux <didier.barvaux@toulouse.viveris.com>; Didier Barvaux <didier@barvaux.org>; The hackers from ROHC for Linux; David Moreau from TAS

Define Documentation

#define L 5

#define LIST_COMP_WINDOW 100

Referenced by d_generic_destroy().

#define MAX_ITEM 15

Function Documentation

void* d_generic_create ( void )

Create the generic decompression context.

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

Returns:: The newly-created generic decompression context

Referenced by d_ip_create(), d_rtp_create(), d_udp_create(), and d_udp_lite_create().

int d_generic_decode	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		const unsigned char *const	rohc_packet,
		const unsigned int	rohc_length,
		int	second_byte,
		unsigned char *	dest
	)

Decode one IR-DYN, UO-0, UO-1 or UOR-2 packet, but not IR packet.

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

Parameters:

decomp	The ROHC decompressor
context	The decompression context
rohc_packet	The ROHC packet to decode
rohc_length	The length of the ROHC packet
second_byte	The offset for the second byte of the ROHC packet (depends on the CID encoding and the packet type, may not exist in packet)
dest	OUT: The decoded IP packet

Returns:: The length of the uncompressed IP packet or ROHC_ERROR if an error occurs or ROHC_ERROR_CRC if a CRC error occurs

References d_generic_context::active1, d_generic_context::active2, cmp_generic_changes(), d_generic_context::current_packet_time, d_generic_decode(), decode_irdyn(), decode_uo0(), decode_uo1(), decode_uor2(), find_packet_type(), d_generic_changes::ip, ip_get_version(), IPV4, d_generic_context::last1, d_generic_context::last2, d_generic_context::multiple_ip, d_generic_changes::nbo, NO_CONTEXT, PACKET_IR_DYN, d_generic_context::packet_type, PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, d_generic_changes::rnd, rohc_debugf, ROHC_ERROR, rohc_get_packet_descr(), ROHC_NEED_REPARSE, d_context::specific, d_context::state, STATIC_CONTEXT, and synchronize().

Referenced by d_generic_decode(), and d_udp_lite_decode().

int d_generic_decode_ir	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		const unsigned char *const	rohc_packet,
		const unsigned int	rohc_length,
		int	large_cid_len,
		int	is_addcid_used,
		unsigned char *	dest
	)

Decode one IR packet.

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

Parameters:

decomp	The ROHC decompressor
context	The decompression context
rohc_packet	The ROHC packet to decode
rohc_length	The length of the ROHC packet to decode
large_cid_len	The length of the large CID field
is_addcid_used	Whether the add-CID field is present or not
dest	The decoded IP packet

Returns:: The length of the uncompressed IP packet or ROHC_ERROR if an error occurs

Referenced by d_udp_lite_decode_ir().

void d_generic_destroy ( void * context )

Destroy the context.

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

Parameters:

context The compression context

References d_generic_context::active1, d_generic_context::active2, destroy_list(), list_decomp::free_table, d_generic_context::last1, d_generic_context::last2, LIST_COMP_WINDOW, d_generic_context::list_decomp1, d_generic_context::list_decomp2, list_decomp::list_table, d_generic_context::specific, and zfree.

Referenced by d_rtp_create(), d_udp_create(), d_udp_destroy(), d_udp_lite_create(), and d_udp_lite_destroy().

unsigned int d_generic_detect_ir_dyn_size	(	struct d_context *	context,
		unsigned char *	packet,
		unsigned int	plen,
		unsigned int	large_cid_len
	)

Find the length of the IR-DYN header.

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


 Basic structure of the IR-DYN packet (5.7.7.2):

      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  :         Add-CID octet         : if for small CIDs and CID != 0
    +---+---+---+---+---+---+---+---+
 2  | 1   1   1   1   1   0   0   0 | IR-DYN packet type
    +---+---+---+---+---+---+---+---+
    :                               :
 3  /     0-2 octets of CID info    / 1-2 octets if for large CIDs
    :                               :
    +---+---+---+---+---+---+---+---+
 4  |            Profile            | 1 octet
    +---+---+---+---+---+---+---+---+
 5  |              CRC              | 1 octet
    +---+---+---+---+---+---+---+---+
    |                               |
 6  /         Dynamic chain         / variable length
    |                               |
    +---+---+---+---+---+---+---+---+
 7  |             SN                | 2 octets if not RTP
    +---+---+---+---+---+---+---+---+
    :                               :
 8  /           Payload             / variable length
    :                               :
     - - - - - - - - - - - - - - - -

The function computes the length of the fields 2 + 4-7, ie. the first byte, the Profile and CRC fields and the dynamic chains (outer and inner IP headers).

Parameters:

context	The decompression context
packet	The IR-DYN packet after the Add-CID byte if present (ie. field 2 in the figure)
plen	The length of the IR-DYN packet minus the Add-CID byte
large_cid_len	The size of the large CID field (ie. field 3 in the figure)

Returns:: The length of the IR-DYN header, 0 if an error occurs

References d_generic_context::active1, d_generic_context::active2, d_generic_changes::ip, ip_get_protocol(), ip_get_version(), IPV4, IPV4_DYN_PART_SIZE, d_generic_context::list_decomp1, d_generic_context::list_decomp2, rohc_debugf, list_decomp::size_ext, d_context::specific, and version.

Referenced by ip_detect_ir_dyn_size(), and rtp_detect_ir_dyn_size().

unsigned int d_generic_detect_ir_size	(	struct d_context *	context,
		unsigned char *	packet,
		unsigned int	plen,
		unsigned int	large_cid_len
	)

Find the length of the IR header.

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


 Basic structure of the IR packet (5.7.7.1):

      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  |         Add-CID octet         |  if for small CIDs and CID != 0
    +---+---+---+---+---+---+---+---+
 2  | 1   1   1   1   1   1   0 | D |
    +---+---+---+---+---+---+---+---+
    |                               |
 3  /    0-2 octets of CID info     /  1-2 octets if for large CIDs
    |                               |
    +---+---+---+---+---+---+---+---+
 4  |            Profile            |  1 octet
    +---+---+---+---+---+---+---+---+
 5  |              CRC              |  1 octet
    +---+---+---+---+---+---+---+---+
    |                               |
 6  |         Static chain          |  variable length
    |                               |
    +---+---+---+---+---+---+---+---+
    |                               |
 7  |         Dynamic chain         |  present if D = 1, variable length
    |                               |
    +---+---+---+---+---+---+---+---+
 8  |             SN                |  2 octets if not RTP
    +---+---+---+---+---+---+---+---+
    |                               |
 9  |           Payload             |  variable length
    |                               |
     - - - - - - - - - - - - - - - -

The function computes the length of the fields 2 + 4-7, ie. the first byte, the Profile and CRC fields and the static and dynamic chains (outer and inner IP headers).

Parameters:

context	The decompression context
packet	The pointer on the IR packet minus the Add-CID byte (ie. the field 2 in the figure)
plen	The length of the IR packet minus the Add-CID byte
large_cid_len	The size of the large CID field (ie. the field 3 in the figure)

Returns:: The length of the IR header, 0 if an error occurs

References GET_BIT_0, GET_REAL, d_profile::get_static_part, IPV4, IPV4_DYN_PART_SIZE, IPV6, d_generic_context::list_decomp1, d_generic_context::list_decomp2, d_context::profile, rohc_debugf, list_decomp::size_ext, and d_context::specific.

Referenced by ip_detect_ir_size(), and rtp_detect_ir_size().

int d_generic_get_sn ( struct d_context * context )

Get the reference SN value of the context.

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

Parameters:

context The decompression context

Returns:: The reference SN value

References d_get_lsb_ref(), d_generic_context::sn, and d_context::specific.

rohc_packet_t find_packet_type	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		const unsigned char *	packet,
		const size_t	rohc_length,
		int	second_byte
	)

Find out of which type is the ROHC packet.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
packet	The ROHC packet
rohc_length	The length of the ROHC packet
second_byte	The offset for the second byte of the ROHC packet (depends on the CID encoding and the packet type, may not exist in packet)

Returns:: The packet type among PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UO_1_ID, PACKET_UOR_2, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, PACKET_UOR_2_ID, PACKET_IR_DYN, PACKET_IR or PACKET_UNKNOWN

References GET_BIT_5, GET_BIT_5_7, GET_BIT_6, GET_BIT_6_7, GET_BIT_7, d_profile::id, d_generic_changes::ip, ip_get_version(), IPV4, d_generic_context::last1, d_generic_context::last2, d_generic_context::multiple_ip, PACKET_IR, PACKET_IR_DYN, PACKET_UNKNOWN, PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, d_context::profile, d_generic_changes::rnd, rohc_debugf, ROHC_PROFILE_RTP, and d_context::specific.

Referenced by d_generic_decode(), and d_udp_lite_decode().

Data Structures

Defines

Functions

Detailed Description

Define Documentation

Function Documentation