rohc_decomp.c File Reference

ROHC decompression routines. More...

#include "rohc_decomp.h"
#include "rohc_traces.h"
#include "rohc_time.h"
#include "rohc_debug.h"
#include "feedback.h"
#include "wlsb.h"
#include "decode.h"
#include "crc.h"
#include <assert.h>

Include dependency graph for rohc_decomp.c:

Functions
void	context_array_increase (struct rohc_decomp *decomp, int highest_cid)
	Increases the context array size in sizes of 2^x (max 16384).
void	context_array_decrease (struct rohc_decomp *decomp)
	Decreases the context array size in sizes of 2^x (min 16).
struct d_context *	find_context (struct rohc_decomp *decomp, int cid)
	Find one decompression context thanks to its CID.
struct d_context *	context_create (struct rohc_decomp *decomp, int with_cid, struct d_profile *profile)
	Create one new decompression context with profile specific data.
void	context_free (struct d_context *context)
	Destroy one decompression context and the profile specific data associated with it.
struct rohc_decomp *	rohc_alloc_decompressor (struct rohc_comp *compressor)
	Create one ROHC decompressor.
void	rohc_free_decompressor (struct rohc_decomp *decomp)
	Destroy one ROHC decompressor.
int	rohc_decompress (struct rohc_decomp *decomp, unsigned char *ibuf, int isize, unsigned char *obuf, int osize)
	Decompress a ROHC packet.
int	rohc_decompress_both (struct rohc_decomp *decomp, unsigned char *ibuf, int isize, unsigned char *obuf, int osize, int large)
	Decompress both large and small CID packets.
int	d_decode_header (struct rohc_decomp *decomp, unsigned char *ibuf, int isize, unsigned char *obuf, int osize, struct d_decode_data *ddata)
	Decompress the compressed headers.
void	d_optimistic_feedback (struct rohc_decomp *decomp, int rohc_status, int cid, int addcidUsed, int largecidUsed, struct d_context *context)
	Send feedback in Optimistic Mode.
void	d_operation_mode_feedback (struct rohc_decomp *decomp, int rohc_status, int cid, int addcidUsed, int largecidUsed, int mode, struct d_context *context)
	Send feedback depending on the mode: Unidirectional, Optimistic or Reliable.
void	clear_statistics (struct rohc_decomp *decomp)
	Clear all the statistics.
int	rohc_d_statistics (struct rohc_decomp *decomp, unsigned int indent, char *buffer)
	Output the decompression statistics of one decompressor to a buffer. The buffer must be large enough to store all the statistics.
int	rohc_d_context (struct rohc_decomp *decomp, int index, unsigned int indent, char *buffer)
	Output the statistics of one decompression context to a buffer.
void	d_change_mode_feedback (struct rohc_decomp *decomp, struct d_context *context)
	Create a feedback ACK packet telling the compressor to change state.
void	user_interactions (struct rohc_decomp *decomp, int feedback_maxval)
	Update feedback interval by the user.
Variables
struct d_profile d_uncomp_profile d_udp_profile d_ip_profile d_udplite_profile	d_rtp_profile
	Define the decompression part of the RTP profile as described in the RFC 3095.

---

Detailed Description

ROHC decompression routines.

Author:

Didier Barvaux <didier.barvaux@toulouse.viveris.com>

Didier Barvaux <didier@barvaux.org>

The hackers from ROHC for Linux

David Moreau from TAS

---

Function Documentation

void context_array_decrease

(

struct rohc_decomp *

decomp

)

Decreases the context array size in sizes of 2^x (min 16).

Parameters:

decomp

The ROHC decompressor

References rohc_decomp::contexts, rohc_decomp::num_contexts, rohc_debugf, and zfree.

void context_array_increase	(	struct rohc_decomp *	decomp,
		int	highest_cid
	)

Increases the context array size in sizes of 2^x (max 16384).

Parameters:

decomp	The ROHC decompressor
highest_cid	Highest CID to adapt context array size with

References rohc_decomp::contexts, rohc_decomp::num_contexts, rohc_debugf, and zfree.

Referenced by d_decode_header(), and rohc_alloc_decompressor().

struct d_context* context_create	(	struct rohc_decomp *	decomp,
		int	with_cid,
		struct d_profile *	profile
	)		[read]

Create one new decompression context with profile specific data.

Parameters:

decomp	The ROHC decompressor
with_cid	The CID of the new context (not implemented)
profile	The profile to be assigned with the new context

Returns:

The new context if successful, NULL otherwise

References d_profile::allocate_decode_data, c_create_wlsb(), c_destroy_wlsb(), d_context::curval, d_context::first_used, d_profile::free_decode_data, d_context::header_16_compressed, d_context::header_16_uncompressed, d_context::header_compressed_size, d_context::header_uncompressed_size, d_context::latest_used, d_context::mode, NO_CONTEXT, d_context::num_decomp_failures, d_context::num_decomp_repairs, d_context::num_recv_ir, d_context::num_recv_ir_dyn, d_context::num_recv_packets, d_context::num_sent_feedbacks, d_context::profile, rohc_debugf, d_context::specific, d_context::state, d_context::total_16_compressed, d_context::total_16_uncompressed, d_context::total_compressed_size, d_context::total_uncompressed_size, U_MODE, and zfree.

Referenced by d_decode_header().

void context_free

(

struct d_context *

context

)

Destroy one decompression context and the profile specific data associated with it.

Parameters:

context

The context to destroy

References c_destroy_wlsb(), d_profile::free_decode_data, d_context::header_16_compressed, d_context::header_16_uncompressed, d_context::profile, d_context::specific, d_context::total_16_compressed, d_context::total_16_uncompressed, and zfree.

Referenced by d_decode_header(), and rohc_free_decompressor().

int d_decode_header	(	struct rohc_decomp *	decomp,
		unsigned char *	ibuf,
		int	isize,
		unsigned char *	obuf,
		int	osize,
		struct d_decode_data *	ddata
	)

Decompress the compressed headers.

Parameters:

decomp	The ROHC decompressor
ibuf	The ROHC packet to decompress
isize	The size of the ROHC packet
obuf	The buffer where to store the decompressed packet
osize	The size of the buffer for the decompressed packet
ddata	Decompression-related data (e.g. the context)

Returns:

The size of the decompressed packet

References d_decode_data::active, d_decode_data::addcidUsed, d_decode_data::cid, context_array_increase(), context_create(), context_free(), rohc_decomp::contexts, rohc_decomp::curval, d_is_ir(), d_is_irdyn(), d_profile::decode, d_profile::decode_ir, find_context(), d_decode_data::large_cid_size, rohc_decomp::last_context, d_context::latest_used, rohc_decomp::maxval, rohc_decomp::num_contexts, d_context::num_recv_ir, d_context::num_recv_ir_dyn, d_context::profile, rohc_debugf, ROHC_ERROR_CRC, ROHC_ERROR_NO_CONTEXT, ROHC_FEEDBACK_ONLY, and ROHC_OK.

Referenced by rohc_decompress().

void d_operation_mode_feedback	(	struct rohc_decomp *	decomp,
		int	rohc_status,
		int	cid,
		int	addcidUsed,
		int	largecidUsed,
		int	mode,
		struct d_context *	context
	)

Send feedback depending on the mode: Unidirectional, Optimistic or Reliable.

Parameters:

decomp	The ROHC decompressor
rohc_status	The type of feedback to send: 0 = OK (ack), -1 = ContextInvalid (S-nack), -2 = PackageFailed (Nack)
cid	The Context ID (CID) to which the feedback is related
addcidUsed	Whether add-CID is used or not
largecidUsed	Whether large CIDs are used or not
mode	The mode in which the ROHC decompressor operates: U_MODE, O_MODE or R_MODE
context	The context to which the feedback is related

References d_optimistic_feedback(), O_MODE, R_MODE, and U_MODE.

Referenced by rohc_decompress().

void d_optimistic_feedback	(	struct rohc_decomp *	decomp,
		int	rohc_status,
		int	cid,
		int	addcidUsed,
		int	largecidUsed,
		struct d_context *	context
	)

Send feedback in Optimistic Mode.

Parameters:

decomp	The ROHC decompressor
rohc_status	The type of feedback to send: 0 = OK (ack), -1 = ContextInvalid (S-nack), -2 = PackageFailed (Nack)
cid	The Context ID (CID) to which the feedback is related
addcidUsed	Whether add-CID is used or not
largecidUsed	Whether large CIDs are used or not
context	The context to which the feedback is related

References ACKTYPE_ACK, ACKTYPE_NACK, ACKTYPE_STATIC_NACK, c_piggyback_feedback(), rohc_decomp::compressor, rohc_decomp::crc_table_8, f_add_option(), f_feedback2(), f_wrap_feedback(), FULL_CONTEXT, d_profile::get_sn, d_context::mode, NO_CONTEXT, NO_CRC, d_context::num_sent_feedbacks, O_MODE, OPT_TYPE_SN_NOT_VALID, d_context::profile, rohc_debugf, ROHC_ERROR_CRC, ROHC_ERROR_NO_CONTEXT, ROHC_ERROR_PACKET_FAILED, ROHC_OK, d_context::state, STATIC_CONTEXT, WITH_CRC, and zfree.

Referenced by d_operation_mode_feedback().

struct d_context* find_context	(	struct rohc_decomp *	decomp,
		int	cid
	)		[read]

Find one decompression context thanks to its CID.

Parameters:

decomp	The ROHC decompressor
cid	The CID of the context to find out

Returns:

The context if found, NULL otherwise

References rohc_decomp::contexts, and rohc_decomp::num_contexts.

Referenced by d_decode_header().

int rohc_d_context	(	struct rohc_decomp *	decomp,
		int	index,
		unsigned int	indent,
		char *	buffer
	)

Output the statistics of one decompression context to a buffer.

The buffer must be large enough to store the statistics of one context.

Parameters:

decomp	The ROHC decompressor
index	The index of the decompression context in the contexts array
indent	The level of indentation to add during output
buffer	The buffer where to outputs the statistics

Returns:

The length of data written to the buffer

References c_mean_wlsb(), c_sum_wlsb(), rohc_decomp::contexts, d_profile::description, d_context::first_used, d_context::header_16_compressed, d_context::header_16_uncompressed, d_context::header_compressed_size, d_context::header_uncompressed_size, d_context::latest_used, d_context::mode, rohc_decomp::num_contexts, d_context::num_decomp_failures, d_context::num_decomp_repairs, d_context::num_recv_ir, d_context::num_recv_ir_dyn, d_context::num_recv_packets, d_context::num_sent_feedbacks, d_context::profile, d_context::state, d_context::total_16_compressed, d_context::total_16_uncompressed, d_context::total_compressed_size, and d_context::total_uncompressed_size.

Referenced by rohc_d_statistics().

int rohc_decompress_both	(	struct rohc_decomp *	decomp,
		unsigned char *	ibuf,
		int	isize,
		unsigned char *	obuf,
		int	osize,
		int	large
	)

Decompress both large and small CID packets.

Parameters:

decomp	The ROHC decompressor
ibuf	The ROHC packet to decompress
isize	The size of the ROHC packet
obuf	The buffer where to store the decompressed packet
osize	The size of the buffer for the decompressed packet
large	Whether the packet use large CID or not

Returns:

The size of the decompressed packet

References medium::cid_type, rohc_decomp::medium, rohc_decompress(), ROHC_LARGE_CID, and ROHC_SMALL_CID.

---

Variable Documentation

struct d_profile d_uncomp_profile d_udp_profile d_ip_profile d_udplite_profile d_rtp_profile

Define the decompression part of the RTP profile as described in the RFC 3095.