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

#include "d_generic.h"
#include "d_rtp.h"
#include "config.h"
#include "rohc_traces.h"
#include <assert.h>

Include dependency graph for d_generic.c:

Defines
#define	MIN(a, b) ((a) < (b) ? (a) : (b))
#define	IPV4_DYN_PART_SIZE 6
	The size (in bytes) of the IPv4 dynamic part.
Functions
int	decode_irdyn (struct rohc_decomp decomp, struct d_context context, unsigned char head, unsigned char packet, unsigned char *dest, int plen)
	Decode one IR-DYN packet.
int	decode_uo1 (struct rohc_decomp decomp, struct d_context context, unsigned char head, unsigned char packet, unsigned char *dest, int plen)
	Decode one UO-1 packet.
int	decode_uo0 (struct rohc_decomp decomp, struct d_context context, unsigned char head, unsigned char packet, unsigned char *dest, int plen)
	Decode one UO-0 packet.
int	do_decode_uo0_and_uo1 (struct d_context context, const unsigned char packet, unsigned char dest, int plen, int sn_bits, int nb_of_sn_bits, int id, int nb_of_id_bits, int id2, int sn, int calc_crc)
	Decode one UO-0 or UO-1 packet.
int	decode_uor2 (struct rohc_decomp decomp, struct d_context context, unsigned char head, unsigned char packet, unsigned char *dest, int plen)
	Decode one UOR-2 packet.
int	do_decode_uor2 (struct rohc_decomp decomp, struct d_context context, unsigned char packet, unsigned char dest, int plen, int id, int id2, int sn, int sn_size, int sn_bits, int ext, int calc_crc)
	Decode one UOR-2 packet.
int	decode_extension0 (unsigned char packet, unsigned int length, int packet_type, int sn, int ip_id, int ts)
	Decode the extension 0 of the UOR-2 packet.
int	decode_extension1 (unsigned char packet, unsigned int length, int packet_type, int sn, int ip_id, int ts)
	Decode the extension 1 of the UOR-2 packet.
int	decode_extension2 (unsigned char packet, unsigned int length, int packet_type, int sn, int ip_id, int ip_id2, int *ts)
	Decode the extension 2 of the UOR-2 packet.
int	decode_extension3 (struct rohc_decomp decomp, struct d_context context, unsigned char packet, unsigned int length, int sn, int sn_size, int is_id_updated, int is_id2_updated, int is_rtp_present, int *is_pt_updated)
	Decode the extension 3 of the UOR-2 packet.
int	extension_type (const unsigned char *packet)
	Find out which extension is carried by the UOR-2 packet.
int	d_decode_static_ip (const unsigned char packet, const unsigned int length, struct d_generic_changes info)
	Decode the IP static part of a ROHC packet.
int	d_decode_static_ip4 (const unsigned char packet, const unsigned int length, struct ip_packet ip)
	Decode the IPv4 static part of a ROHC packet.
int	d_decode_static_ip6 (const unsigned char packet, const unsigned int length, struct ip_packet ip)
	Decode the IPv6 static part of a ROHC packet.
int	d_decode_dynamic_ip (const unsigned char packet, unsigned int length, struct d_generic_changes info, struct list_decomp *decomp)
	Decode the IP dynamic part of a ROHC packet.
int	d_decode_dynamic_ip4 (const unsigned char packet, unsigned int length, struct ip_packet ip, int rnd, int nbo)
	Decode the IPv4 dynamic part of a ROHC packet.
int	d_decode_dynamic_ip6 (const unsigned char packet, unsigned int length, struct ip_packet ip, struct list_decomp decomp, struct d_generic_changes info)
	Decode the IPv6 dynamic part of a ROHC packet.
int	decode_outer_header_flags (struct d_context context, unsigned char flags, unsigned char fields, unsigned int length, struct d_generic_changes info, int *updated_id)
	Decode the outer IP header flags and fields.
int	decode_inner_header_flags (struct d_context context, unsigned char flags, unsigned char fields, unsigned int length, struct d_generic_changes info)
	Decode the inner IP header flags and fields.
unsigned int	build_uncompressed_ip (struct d_generic_changes active, unsigned char dest, unsigned int payload_size, struct list_decomp *decomp)
	Build an uncompressed IP header.
unsigned int	build_uncompressed_ip4 (struct d_generic_changes active, unsigned char dest, unsigned int payload_size)
	Build an uncompressed IPv4 header.
unsigned int	build_uncompressed_ip6 (struct d_generic_changes active, unsigned char dest, unsigned int payload_size, struct list_decomp *decomp)
	Build an uncompressed IPv6 header.
void	copy_generic_changes (struct d_generic_changes dst, struct d_generic_changes src)
	Copy the header changes object into another one.
int	cmp_generic_changes (struct d_generic_changes first, struct d_generic_changes second)
	Compare two header changes objects.
void	sync_on_failure (struct d_generic_context *context)
	Replace the active header changes with the last ones.
void	synchronize (struct d_generic_context *context)
	Replace last header changes with the active ones.
void	update_inter_packet (struct d_generic_context *context)
	Update the inter-packet time, a sort of average over the last inter-packet times.
int	act_on_crc_failure (struct rohc_decomp decomp, struct d_context context, unsigned char packet, unsigned char dest, int sn_size, int sn, int sn_bits, int payload_size, int id, int id_size, int id2, int *calc_crc, int real_crc, int ext)
	Try to repair the SN in one of two different ways.
int	check_id (struct list_decomp *decomp, int gen_id)
	Check if the gen_id is present in list table.
int	get_bit_index (unsigned char byte, int index)
	Get the bit in the byte at the specified index.
int	check_ip6_index (struct list_decomp *decomp, int index)
	Check if the index is correct in IPv6 table.
int	encode_ip6_extension (struct d_generic_changes active, struct list_decomp decomp, unsigned char *dest)
	Build an extension list in IPv6 header.
void	create_ip6_item (const unsigned char data, int length, int index, struct list_decomp decomp)
	Create an IPv6 item extension list.
void	ip6_d_init_table (struct list_decomp *decomp)
	Initialize the tables IPv6 extension in decompressor.
int	get_ip6_ext_size (const unsigned char *ext)
	Get the size of the extension in bytes.
void *	d_generic_create (void)
	Create the generic decompression context.
void	d_generic_destroy (void *context)
	Destroy the context.
int	d_algo_list_decompress (struct list_decomp decomp, const unsigned char packet)
	Algorithm of list decompression.
int	decode_type_0 (struct list_decomp decomp, const unsigned char packet, int gen_id, int ps, int m)
	Decode an extension list type 0.
int	decode_type_1 (struct list_decomp decomp, const unsigned char packet, int gen_id, int ps, int m, int ref_id)
	Decode an extension list type 1.
int	decode_type_2 (struct list_decomp decomp, const unsigned char packet, int gen_id, int ps, int ref_id)
	Decode an extension list type 2.
int	decode_type_3 (struct list_decomp decomp, const unsigned char packet, int gen_id, int ps, int m, int ref_id)
	Decode an extension list type 3.
int	d_generic_decode_ir (struct rohc_decomp decomp, struct d_context context, unsigned char packet, int plen, 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 packet, unsigned int plen, unsigned int large_cid_len)
	Find the length of the IR-DYN header.
int	d_generic_decode (struct rohc_decomp decomp, struct d_context context, unsigned char packet, int size, 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_get_sn (struct d_context *context)
	Get the reference SN value of the context.
int	find_packet_type (struct rohc_decomp decomp, struct d_context context, const unsigned char *packet, 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>; The hackers from ROHC for Linux; David Moreau from TAS

Define Documentation

#define IPV4_DYN_PART_SIZE 6

The size (in bytes) of the IPv4 dynamic part.

According to RFC3095 section 5.7.7.4: 1 (TOS) + 1 (TTL) + 2 (IP-ID) + 1 (flags) + 1 (header list) = 6 bytes

The size of the generic extension header list field is considered constant because generic extension header list is not supported yet and thus 1 byte of zero is used.

Referenced by d_decode_dynamic_ip4(), d_generic_detect_ir_dyn_size(), and d_generic_detect_ir_size().

#define MIN	(	a,
		b
	)	((a) < (b) ? (a) : (b))

Get the minimum of two values

Referenced by decode_type_2(), and decode_type_3().

Function Documentation

int act_on_crc_failure	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	packet,
		unsigned char *	dest,
		int	sn_size,
		int *	sn,
		int	sn_bits,
		int *	payload_size,
		int *	id,
		int	id_size,
		int *	id2,
		int *	calc_crc,
		int	real_crc,
		int	ext
	)

Try to repair the SN in one of two different ways.

TODO: check this function

Parameters:

decomp	The ROHC decompressor
context	The decompression context
packet	The ROHC packet with a wrong CRC
dest	The decoded IP packet
sn_size	The number of bits used to code the SN
sn	OUT: The Sequence Number (SN) value
sn_bits	The LSB part of the SN
payload_size	OUT: The length of the ROHC payload
id	OUT: The outer IP-ID
id_size	The number of bits used to code the IP-ID
id2	OUT: The inner IP-ID
calc_crc	OUT: The computed CRC
real_crc	The CRC transmitted in the ROHC packet
ext	Whether the UOR-2 packet owns an extension or not

Returns:: Always return ROHC_ERROR_CRC

Referenced by decode_uo0(), decode_uo1(), and decode_uor2().

unsigned int build_uncompressed_ip	(	struct d_generic_changes *	active,
		unsigned char *	dest,
		unsigned int	payload_size,
		struct list_decomp *	decomp
	)

Build an uncompressed IP header.

Parameters:

active	The IP header changes
dest	The buffer to store the IP header (MUST be at least of sizeof(struct iphdr) or sizeof(struct ip6_hdr) bytes depending on the IP version)
payload_size	The length of the IP payload
decomp	The list decompressor (IPv6 only)

Returns:: The length of the IP header

References build_uncompressed_ip4(), build_uncompressed_ip6(), d_generic_changes::ip, ip_get_version(), and IPV4.

Referenced by d_generic_decode_ir(), decode_irdyn(), do_decode_uo0_and_uo1(), and do_decode_uor2().

unsigned int build_uncompressed_ip4	(	struct d_generic_changes *	active,
		unsigned char *	dest,
		unsigned int	payload_size
	)

Build an uncompressed IPv4 header.

Parameters:

active	The IPv4 header changes
dest	The buffer to store the IPv4 header (MUST be at least of sizeof(struct iphdr) bytes)
payload_size	The length of the IPv4 payload

Returns:: The length of the IPv4 header

References ip_packet::header, d_generic_changes::ip, d_generic_changes::nbo, rohc_debugf, and ip_packet::v4.

Referenced by build_uncompressed_ip().

unsigned int build_uncompressed_ip6	(	struct d_generic_changes *	active,
		unsigned char *	dest,
		unsigned int	payload_size,
		struct list_decomp *	decomp
	)

Build an uncompressed IPv6 header.

Parameters:

active	The IPv6 header changes
dest	The buffer to store the IPv6 header (MUST be at least of sizeof(struct ip6_hdr) bytes)
payload_size	The length of the IPv6 payload
decomp	The list decompressor

Returns:: The length of the IPv6 header

References d_generic_changes::complist, list_decomp::counter_list, list_decomp::encode_extension, c_list::first_elt, ip_packet::header, d_generic_changes::ip, list_elt::item, list_decomp::list_decomp, list_decomp::list_table, rohc_debugf, d_generic_changes::size_list, size_list(), item::type, and ip_packet::v6.

Referenced by build_uncompressed_ip().

int check_id	(	struct list_decomp *	decomp,
		int	gen_id
	)

Check if the gen_id is present in list table.

Parameters:

decomp	The list decompressor
gen_id	The specified id

Returns:: 1 if successfull, 0 else

References c_list::gen_id, LIST_COMP_WINDOW, and list_decomp::list_table.

Referenced by decode_type_0(), decode_type_1(), decode_type_2(), and decode_type_3().

int check_ip6_index	(	struct list_decomp *	decomp,
		int	index
	)

Check if the index is correct in IPv6 table.

Parameters:

decomp	The list decompressor
index	The specified index

Returns:: 1 if successfull, 0 else

References rohc_debugf.

Referenced by d_generic_create().

int cmp_generic_changes	(	struct d_generic_changes *	first,
		struct d_generic_changes *	second
	)

Compare two header changes objects.

Parameters:

first	One header changes object
second	Another header changes object

Returns:: 1 if the two objects match, 0 otherwise

References d_generic_changes::ip, d_generic_changes::nbo, d_generic_changes::next_header, d_generic_changes::next_header_len, and d_generic_changes::rnd.

Referenced by d_generic_decode().

void copy_generic_changes	(	struct d_generic_changes *	dst,
		struct d_generic_changes *	src
	)

Copy the header changes object into another one.

Parameters:

dst	The destination header changes
src	The source header changes

References d_generic_changes::ip, d_generic_changes::nbo, d_generic_changes::next_header, d_generic_changes::next_header_len, d_generic_changes::rnd, and rohc_debugf.

Referenced by sync_on_failure(), and synchronize().

void create_ip6_item	(	const unsigned char *	data,
		int	length,
		int	index,
		struct list_decomp *	decomp
	)

Create an IPv6 item extension list.

Parameters:

data	The data in the item
length	The length of the item
index	The index of the item in based table
decomp	The list decompressor

References item::ahhdr, list_decomp::based_table, item::data, item::dest, item::hbh, item::header, ip6_ahhdr::ip6ah_len, ip6_ahhdr::ip6ah_nxt, d_translation::known, item::length, rohc_debugf, item::rthdr, list_decomp::trans_table, and zfree.

Referenced by d_generic_create().

int d_algo_list_decompress	(	struct list_decomp *	decomp,
		const unsigned char *	packet
	)

Algorithm of list decompression.

Parameters:

decomp	The list decompressor
packet	The ROHC packet to decompress

Returns:: the size of the compressed list

References decode_type_0(), decode_type_1(), decode_type_2(), decode_type_3(), GET_BIT_0_3, GET_BIT_4, GET_BIT_6_7, GET_REAL, list_decomp::list_decomp, m, and rohc_debugf.

Referenced by d_generic_detect_ir_dyn_size(), and d_generic_detect_ir_size().

int d_decode_dynamic_ip	(	const unsigned char *	packet,
		unsigned int	length,
		struct d_generic_changes *	info,
		struct list_decomp *	decomp
	)

Decode the IP dynamic part of a ROHC packet.

See 5.7.7.3 and 5.7.7.4 in RFC 3095 for details.

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
info	The decoded IP header information
decomp	The list decompressor (only for IPv6)

Returns:: The number of bytes read in the ROHC packet, -1 in case of failure

References d_decode_dynamic_ip4(), d_decode_dynamic_ip6(), d_generic_changes::ip, ip_get_version(), IPV4, d_generic_changes::nbo, and d_generic_changes::rnd.

Referenced by d_generic_decode_ir(), and decode_irdyn().

int d_decode_dynamic_ip4	(	const unsigned char *	packet,
		unsigned int	length,
		struct ip_packet *	ip,
		int *	rnd,
		int *	nbo
	)

Decode the IPv4 dynamic part of a ROHC packet.

See 5.7.7.4 in RFC 3095 for details. Generic extension header list is not managed yet.

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
ip	The decoded IP packet
rnd	Boolean to store whether the IP-ID is random or not
nbo	Boolean to store whether the IP-ID is in NBO or not

Returns:: The number of bytes read in the ROHC packet, -1 in case of failure

References GET_BIT_0_7, GET_BIT_5, GET_BIT_6, GET_BIT_7, GET_NEXT_16_BITS, GET_REAL, ip_get_tos(), ip_get_ttl(), ip_set_tos(), ip_set_ttl(), IPV4_DYN_PART_SIZE, ipv4_get_df(), ipv4_get_id(), ipv4_set_df(), ipv4_set_id(), and rohc_debugf.

Referenced by d_decode_dynamic_ip().

int d_decode_dynamic_ip6	(	const unsigned char *	packet,
		unsigned int	length,
		struct ip_packet *	ip,
		struct list_decomp *	decomp,
		struct d_generic_changes *	info
	)

Decode the IPv6 dynamic part of a ROHC packet.

See 5.7.7.3 in RFC 3095 for details. Generic extension header list is not managed yet.

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
ip	The decoded IP packet
decomp	The list decompressor
info	The decoded IP header information

Returns:: The number of bytes read in the ROHC packet, -1 in case of failure

References list_decomp::counter_list, c_list::first_elt, GET_BIT_0_7, get_elt(), ip_get_tos(), ip_get_ttl(), ip_set_tos(), ip_set_ttl(), list_elt::item, item::length, list_decomp::list_decomp, list_decomp::list_table, list_decomp::ref_list, list_decomp::ref_ok, rohc_debugf, list_decomp::size_ext, d_generic_changes::size_list, and size_list().

Referenced by d_decode_dynamic_ip().

int d_decode_static_ip	(	const unsigned char *	packet,
		const unsigned int	length,
		struct d_generic_changes *	info
	)

Decode the IP static part of a ROHC packet.

See 5.7.7.3 and 5.7.7.4 in RFC 3095 for details.

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
info	The decoded IP header information

Returns:: The number of bytes read in the ROHC packet, -1 in case of failure

References d_decode_static_ip4(), d_decode_static_ip6(), GET_BIT_4_7, d_generic_changes::ip, ip_new(), IPV4, IPV6, and rohc_debugf.

Referenced by d_generic_decode_ir().

int d_decode_static_ip4	(	const unsigned char *	packet,
		const unsigned int	length,
		struct ip_packet *	ip
	)

Decode the IPv4 static part of a ROHC packet.

See 5.7.7.4 in RFC 3095 for details.

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
ip	The decoded IP packet

Returns:: The number of bytes read in the ROHC packet, -1 in case of failure

References GET_BIT_0_7, GET_BIT_4_7, ip_get_protocol(), ip_set_daddr(), ip_set_protocol(), ip_set_saddr(), IPV4, ipv4_get_daddr(), ipv4_get_saddr(), rohc_debugf, ip_packet::version, and version.

Referenced by d_decode_static_ip().

int d_decode_static_ip6	(	const unsigned char *	packet,
		const unsigned int	length,
		struct ip_packet *	ip
	)

Decode the IPv6 static part of a ROHC packet.

See 5.7.7.3 in RFC 3095 for details.

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
ip	The decoded IP packet

Returns:: The number of bytes read in the ROHC packet, -1 in case of failure

References GET_BIT_0_3, GET_BIT_0_7, GET_BIT_4_7, ip_packet::header, ip_set_daddr(), ip_set_protocol(), ip_set_saddr(), IPV6, IPV6_ADDR, IPV6_ADDR_FORMAT, ipv6_get_daddr(), ipv6_get_flow_label(), ipv6_get_saddr(), ipv6_set_flow_label(), rohc_debugf, ip_packet::v6, ip_packet::version, and version.

Referenced by d_decode_static_ip().

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,
		unsigned char *	packet,
		int	size,
		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
packet	The ROHC packet to decode
size	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)
dest	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_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,
		unsigned char *	packet,
		int	plen,
		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
packet	The ROHC packet to decode
plen	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, list_decomp::temp_list, 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_algo_list_decompress(), 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, 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 d_algo_list_decompress(), 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.

int decode_extension0	(	unsigned char *	packet,
		unsigned int	length,
		int	packet_type,
		int *	sn,
		int *	ip_id,
		int *	ts
	)

Decode the extension 0 of the UOR-2 packet.

Actions taken:

SN value is expanded with 3 lower bits
UOR-2: IP-ID is replaced with 3 bits
UOR-2-ID: IP-ID is expanded with 3 lower bits
UOR-2-RTP or UOR-2-TS: TS is expanded with 3 lower bits

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
packet_type	The type of ROHC packet
sn	IN/OUT: The updated SN value
ip_id	IN/OUT: The updated IP-ID value
ts	OUT: The TS value

Returns:: The data length read from the ROHC packet, -1 in case of error

References GET_BIT_0_2, GET_BIT_3_5, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, and rohc_debugf.

Referenced by do_decode_uor2().

int decode_extension1	(	unsigned char *	packet,
		unsigned int	length,
		int	packet_type,
		int *	sn,
		int *	ip_id,
		int *	ts
	)

Decode the extension 1 of the UOR-2 packet.

Actions taken:

SN value is expanded with 3 lower bits
UOR-2: IP-ID is replaced with 11 bits
UOR-2-RTP: TS is expanded with 11 lower bits
UOR-2-TS: TS is expanded with 3 lower bits, IP-ID replaced with 8 bits
UOR-2-ID: IP-ID is expanded with 3 lower bits, TS is replaced with 8 bits

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
packet_type	The type of ROHC packet
sn	IN/OUT: The updated SN value
ip_id	IN/OUT: The updated IP-ID value
ts	OUT: The TS value

Returns:: The data length read from the ROHC packet, -1 in case of error

References GET_BIT_0_2, GET_BIT_3_5, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, and rohc_debugf.

Referenced by do_decode_uor2().

int decode_extension2	(	unsigned char *	packet,
		unsigned int	length,
		int	packet_type,
		int *	sn,
		int *	ip_id,
		int *	ip_id2,
		int *	ts
	)

Decode the extension 2 of the UOR-2 packet.

Actions taken:

SN value is expanded with 3 lower bits
UOR-2: outer IP-ID is replaced with 11 bits, inner IP-ID is replaced with 8 bits
UOR-2-RTP: TS is expanded with 19 lower bits
UOR-2-TS: TS is expanded with 11 lower bits, inner IP-ID is replaced with 8 bits
UOR-2-ID: TS is replaced with 8 bits, inner IP-ID is expanded with 11 lower bits

Parameters:

packet	The ROHC packet to decode
length	The length of the ROHC packet
packet_type	The type of ROHC packet
sn	IN/OUT: The updated SN value
ip_id	IN/OUT: The updated inner IP-ID value
ip_id2	OUT: The outer IP-ID value
ts	OUT: The TS value

Returns:: The data length read from the ROHC packet, -1 in case of error

References GET_BIT_0_2, GET_BIT_3_5, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, and rohc_debugf.

Referenced by do_decode_uor2().

int decode_extension3	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	packet,
		unsigned int	length,
		int *	sn,
		int *	sn_size,
		int *	is_id_updated,
		int *	is_id2_updated,
		int *	is_rtp_present,
		int *	is_pt_updated
	)

Decode the extension 3 of the UOR-2 packet.

Actions taken:

update random fields in the header changes,
the SN is eventually expanded with 8 lower bits.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
packet	The ROHC packet to decode
length	The length of the ROHC packet
sn	IN/OUT: The updated SN value
sn_size	IN/OUT: The new SN size
is_id_updated	OUT: Whether the outer IP-ID is updated by the extension or not
is_id2_updated	OUT: Whether the inner IP-ID is updated by the extension or not
is_rtp_present	OUT: Whether RTP flags & fields are present or not
is_pt_updated	OUT: Whether RTP PT is updated by the extension or not

Returns:: The data length read from the ROHC packet, -2 in case packet must be parsed again, -1 in case of error

References d_generic_context::active1, d_generic_context::active2, d_add_ts_stride(), d_change_mode_feedback(), d_decode_ts(), d_lsb_decode(), d_sdvalue_decode(), d_sdvalue_size(), decode_inner_header_flags(), decode_outer_header_flags(), GET_BIT_0, GET_BIT_1, GET_BIT_2, GET_BIT_3, GET_BIT_3_4, GET_BIT_4, GET_BIT_5, GET_BIT_6_7, GET_BIT_7, GET_NEXT_16_BITS, GET_REAL, d_profile::id, d_generic_changes::ip, ipv4_get_id(), ipv4_set_id(), d_rtp_context::m, MAX_BITS_IN_4_BYTE_SDVL, d_context::mode, d_generic_context::multiple_ip, d_generic_context::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, d_context::profile, d_rtp_context::pt, rohc_debugf, ROHC_PROFILE_RTP, d_rtp_context::rp, d_rtp_context::rx, d_generic_context::sn, d_context::specific, d_generic_context::specific, d_rtp_context::timestamp, ts_deducted(), d_rtp_context::ts_received, d_rtp_context::ts_received_size, and d_rtp_context::ts_sc.

Referenced by do_decode_uor2().

int decode_inner_header_flags	(	struct d_context *	context,
		unsigned char *	flags,
		unsigned char *	fields,
		unsigned int	length,
		struct d_generic_changes *	info
	)

Decode the inner IP header flags and fields.

Store the values in an IP header info structure.


  Inner IP header flags (5.7.5):

       0     1     2     3     4     5     6     7
     ..... ..... ..... ..... ..... ..... ..... .....
    | TOS | TTL | DF  | PR  | IPX | NBO | RND | ip2 |  if ip = 1
     ..... ..... ..... ..... ..... ..... ..... .....

  Inner IP header fields (5.7.5):

    ..... ..... ..... ..... ..... ..... ..... .....
   |         Type of Service/Traffic Class         |  if TOS = 1
    ..... ..... ..... ..... ..... ..... ..... .....
   |         Time to Live/Hop Limit                |  if TTL = 1
    ..... ..... ..... ..... ..... ..... ..... .....
   |         Protocol/Next Header                  |  if PR = 1
    ..... ..... ..... ..... ..... ..... ..... .....
   /         IP extension headers                  /  variable,
    ..... ..... ..... ..... ..... ..... ..... .....   if IPX = 1

Parameters:

context	The decompression context
flags	The ROHC flags that indicate which IP fields are present in the packet
fields	The ROHC packet part that contains some IP header fields
length	The length of the ROHC packet part that contains some IP header fields
info	The IP header info to store the decoded values in

Returns:: The data length read from the ROHC packet, -2 in case packet must be parsed again, -1 in case of error

References GET_BIT_1, GET_BIT_2, GET_BIT_3, GET_BIT_4, GET_BIT_5, GET_BIT_6, GET_BIT_7, GET_REAL, d_profile::id, d_generic_changes::ip, ip_get_version(), ip_set_protocol(), ip_set_tos(), ip_set_ttl(), IPV4, ipv4_get_df(), ipv4_set_df(), d_generic_changes::nbo, d_context::profile, d_generic_changes::rnd, rohc_debugf, and ROHC_PROFILE_RTP.

Referenced by decode_extension3(), and decode_outer_header_flags().

int decode_irdyn	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	head,
		unsigned char *	packet,
		unsigned char *	dest,
		int	plen
	)

Decode one IR-DYN packet.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
head	The first byte the the ROHC packet
packet	The end of the ROHC packet to decode
dest	The decoded IP packet
plen	The length of the ROHC packet

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

References d_generic_context::active1, d_generic_context::active2, d_generic_context::build_next_header, build_uncompressed_ip(), c_add_wlsb(), d_generic_context::counter, d_decode_dynamic_ip(), d_generic_context::decode_dynamic_next_header, FULL_CONTEXT, d_context::header_16_compressed, d_context::header_16_uncompressed, d_context::header_compressed_size, d_context::header_uncompressed_size, d_generic_changes::ip, ip_get_hdrlen(), d_generic_context::list_decomp1, d_generic_context::list_decomp2, d_generic_context::multiple_ip, d_generic_changes::next_header, d_generic_changes::next_header_len, rohc_debugf, ROHC_ERROR, d_generic_changes::size_list, d_context::specific, d_context::state, synchronize(), and update_inter_packet().

Referenced by d_generic_decode().

int decode_outer_header_flags	(	struct d_context *	context,
		unsigned char *	flags,
		unsigned char *	fields,
		unsigned int	length,
		struct d_generic_changes *	info,
		int *	updated_id
	)

Decode the outer IP header flags and fields.

Store the values in an IP header info structure.


  Outer IP header flags (5.7.5):

       0     1     2     3     4     5     6     7
     ..... ..... ..... ..... ..... ..... ..... .....
    | TOS2| TTL2| DF2 | PR2 |IPX2 |NBO2 |RND2 |  I2 |  if ip2 = 1
     ..... ..... ..... ..... ..... ..... ..... .....

  Outer IP header fields

     ..... ..... ..... ..... ..... ..... ..... .....
    |      Type of Service/Traffic Class            |  if TOS2 = 1
     ..... ..... ..... ..... ..... ..... ..... .....
    |         Time to Live/Hop Limit                |  if TTL2 = 1
     ..... ..... ..... ..... ..... ..... ..... .....
    |         Protocol/Next Header                  |  if PR2 = 1
     ..... ..... ..... ..... ..... ..... ..... .....
    /         IP extension header(s)                /  variable,
     ..... ..... ..... ..... ..... ..... ..... .....    if IPX2 = 1
    |                  IP-ID                        |  2 octets,
     ..... ..... ..... ..... ..... ..... ..... .....    if I2 = 1

Parameters:

context	The decompression context
flags	The ROHC flags that indicate which IP fields are present in the packet
fields	The ROHC packet part that contain some IP header fields
length	The length of the ROHC packet part that contains some IP header fields
info	The IP header info to store the decoded values in
updated_id	The boolean to store whether the IP-ID is updated or not

Returns:: The data length read from the ROHC packet, -1 in case of error

References decode_inner_header_flags(), GET_BIT_0, GET_NEXT_16_BITS, GET_REAL, d_generic_changes::ip, ip_get_version(), IPV4, ipv4_get_id(), ipv4_set_id(), and rohc_debugf.

Referenced by decode_extension3().

int decode_type_0	(	struct list_decomp *	decomp,
		const unsigned char *	packet,
		int	gen_id,
		int	ps,
		int	m
	)

Decode an extension list type 0.

Parameters:

decomp	The list decompressor
packet	The ROHC packet to decompress
gen_id	The id of the current list
ps	The ps field
m	The m fiel

Returns:: the size of the compressed list

References list_decomp::based_table, check_id(), list_decomp::counter, list_decomp::counter_list, list_decomp::create_item, empty_list(), c_list::first_elt, c_list::gen_id, GET_BIT_0_2, GET_BIT_0_6, GET_BIT_3, GET_BIT_4_6, GET_BIT_7, list_decomp::get_ext_size, insert_elt(), d_translation::known, L, LIST_COMP_WINDOW, list_decomp::list_table, m, list_decomp::ref_list, list_decomp::ref_ok, rohc_debugf, and list_decomp::trans_table.

Referenced by d_algo_list_decompress().

int decode_type_1	(	struct list_decomp *	decomp,
		const unsigned char *	packet,
		int	gen_id,
		int	ps,
		int	m,
		int	ref_id
	)

Decode an extension list type 1.

Parameters:

decomp	The list decompressor
packet	The ROHC packet to decompress
gen_id	The id of the current list
ps	The ps field
m	The m fiel
ref_id	The id of the reference list

Returns:: the size of the compressed list

References list_decomp::based_table, check_id(), list_decomp::check_index, list_decomp::counter, list_decomp::counter_list, list_decomp::create_item, empty_list(), c_list::first_elt, c_list::gen_id, GET_BIT_0_2, GET_BIT_0_6, GET_BIT_3, GET_BIT_4_6, GET_BIT_7, get_bit_index(), get_elt(), list_decomp::get_ext_size, list_elt::index_table, insert_elt(), list_elt::item, d_translation::known, L, LIST_COMP_WINDOW, list_decomp::list_table, list_decomp::ref_list, list_decomp::ref_ok, rohc_debugf, size_list(), and list_decomp::trans_table.

Referenced by d_algo_list_decompress().

int decode_type_2	(	struct list_decomp *	decomp,
		const unsigned char *	packet,
		int	gen_id,
		int	ps,
		int	ref_id
	)

Decode an extension list type 2.

Parameters:

decomp	The list decompressor
packet	The ROHC packet to decompress
gen_id	The id of the current list
ps	The ps field
ref_id	The id of the reference list

Returns:: the size of the compressed list

References check_id(), list_decomp::counter, list_decomp::counter_list, empty_list(), c_list::first_elt, c_list::gen_id, get_bit_index(), get_elt(), list_elt::index_table, insert_elt(), list_elt::item, L, LIST_COMP_WINDOW, list_decomp::list_table, MIN, list_decomp::ref_list, list_decomp::ref_ok, rohc_debugf, and size_list().

Referenced by d_algo_list_decompress().

int decode_type_3	(	struct list_decomp *	decomp,
		const unsigned char *	packet,
		int	gen_id,
		int	ps,
		int	m,
		int	ref_id
	)

Decode an extension list type 3.

Parameters:

decomp	The list decompressor
packet	The ROHC packet to decompress
gen_id	The id of the current list
ps	The ps field
m	The m fiel
ref_id	The id of the reference list

Returns:: the size of the compressed list

References list_decomp::based_table, check_id(), list_decomp::check_index, list_decomp::counter, list_decomp::counter_list, list_decomp::create_item, empty_list(), c_list::first_elt, c_list::gen_id, GET_BIT_0_2, GET_BIT_0_6, GET_BIT_3, GET_BIT_4_6, GET_BIT_7, get_bit_index(), get_elt(), list_decomp::get_ext_size, GET_REAL, list_elt::index_table, insert_elt(), list_elt::item, d_translation::known, L, LIST_COMP_WINDOW, list_decomp::list_table, MIN, list_decomp::ref_list, list_decomp::ref_ok, rohc_debugf, size_list(), list_decomp::temp_list, and list_decomp::trans_table.

Referenced by d_algo_list_decompress().

int decode_uo0	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	head,
		unsigned char *	packet,
		unsigned char *	dest,
		int	plen
	)

Decode one UO-0 packet.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
head	The first byte the the ROHC packet
packet	The end of the ROHC packet to decode
dest	The decoded IP packet
plen	The length of the ROHC 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

Referenced by d_generic_decode().

int decode_uo1	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	head,
		unsigned char *	packet,
		unsigned char *	dest,
		int	plen
	)

Decode one UO-1 packet.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
head	The first byte the the ROHC packet
packet	The end of the ROHC packet to decode
dest	The decoded IP packet
plen	The length of the ROHC 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

Referenced by d_generic_decode().

int decode_uor2	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	head,
		unsigned char *	packet,
		unsigned char *	dest,
		int	plen
	)

Decode one UOR-2 packet.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
head	The first byte the the ROHC packet
packet	The end of the ROHC packet to decode
dest	The decoded IP packet
plen	The length of the ROHC 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 or ROHC_NEED_REPARSE if packet needs to be parsed again

Referenced by d_generic_decode().

int do_decode_uo0_and_uo1	(	struct d_context *	context,
		const unsigned char *	packet,
		unsigned char *	dest,
		int *	plen,
		int	sn_bits,
		int	nb_of_sn_bits,
		int *	id,
		int	nb_of_id_bits,
		int *	id2,
		int *	sn,
		int *	calc_crc
	)

Decode one UO-0 or UO-1 packet.

Parameters:

context	The decompression context
packet	The ROHC packet to decode
dest	The decoded IP packet
plen	IN/OUT: The length of the ROHC packet
sn_bits	The SN bits as they are transmitted in the ROHC packet
nb_of_sn_bits	The number of bits that code the SN field
id	The outer IP-ID
nb_of_id_bits	The number of bits that code the outer IP-ID field
id2	The inner IP-ID
sn	The SN value
calc_crc	The computed CRC

Returns:: The length of the uncompressed IP packet, -1 in case of error

Referenced by act_on_crc_failure(), decode_uo0(), and decode_uo1().

int do_decode_uor2	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		unsigned char *	packet,
		unsigned char *	dest,
		int *	plen,
		int *	id,
		int *	id2,
		int *	sn,
		int *	sn_size,
		int	sn_bits,
		int	ext,
		int *	calc_crc
	)

Decode one UOR-2 packet.

Parameters:

decomp	The ROHC decompressor
context	The decompression context
packet	The ROHC packet to decode
dest	The decoded IP packet
plen	IN/OUT: The length of the ROHC packet
id	The outer IP-ID
id2	The inner IP-ID
sn	The SN value
sn_size	The SN size
sn_bits	The SN bits as they are transmitted in the ROHC packet
ext	Whether the UOR-2 packet owns an extension or not
calc_crc	The computed CRC

Returns:: The length of the uncompressed IP packet, -2 in case packet must be parsed again, -1 in case of error

Referenced by act_on_crc_failure(), and decode_uor2().

int encode_ip6_extension	(	struct d_generic_changes *	active,
		struct list_decomp *	decomp,
		unsigned char *	dest
	)

Build an extension list in IPv6 header.

Parameters:

active	The IPv6 header changes
decomp	The list decompressor
dest	The buffer to store the IPv6 header

Returns:: The size of the list

References list_decomp::counter_list, item::data, c_list::first_elt, get_elt(), ip_packet::header, d_generic_changes::ip, list_elt::item, item::length, list_decomp::list_table, list_elt::next_elt, list_decomp::ref_list, list_decomp::ref_ok, rohc_debugf, size_list(), item::type, and ip_packet::v6.

Referenced by d_generic_create().

int extension_type ( const unsigned char * packet )

Find out which extension is carried by the UOR-2 packet.

Parameters:

packet The ROHC UOR-2 packet

Returns:: The UOR-2 extension type among PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2 or PACKET_EXT_3

References GET_BIT_6_7.

Referenced by do_decode_uor2().

int find_packet_type	(	struct rohc_decomp *	decomp,
		struct d_context *	context,
		const unsigned char *	packet,
		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
second_byte	The offset for the second byte of the ROHC packet (depends on the CID encoding and the packet type)

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_PROFILE_RTP, and d_context::specific.