rohc_decomp.c File Reference

ROHC decompression routines. More...

#include "rohc_decomp.h"
#include "rohc_decomp_internals.h"
#include "rohc_traces_internal.h"
#include "rohc_time_internal.h"
#include "rohc_utils.h"
#include "rohc_bit_ops.h"
#include "rohc_debug.h"
#include "feedback_create.h"
#include "feedback_parse.h"
#include "sdvl.h"
#include "rohc_add_cid.h"
#include "rohc_decomp_detect_packet.h"
#include "crc.h"
#include <string.h>
#include <stdarg.h>
#include <assert.h>

Include dependency graph for rohc_decomp.c:

Data Structures
struct	rohc_decomp_stream
	The stream informations about a decompressed packet. More...
Functions
static bool	rohc_decomp_create_contexts (struct rohc_decomp *const decomp, const rohc_cid_t max_cid)
	Create the array of decompression contexts.
static struct rohc_decomp_profile *	find_profile (const struct rohc_decomp *const decomp, const rohc_profile_t profile_id)
	Find the ROHC profile with the given profile ID.
static struct rohc_decomp_ctxt *	context_create (struct rohc_decomp decomp, const rohc_cid_t cid, const struct rohc_decomp_profile const profile, const struct rohc_ts arrival_time)
	Create one new decompression context with profile specific data.
static struct rohc_decomp_ctxt *	find_context (const struct rohc_decomp *const decomp, const rohc_cid_t cid)
	Find one decompression context thanks to its CID.
static void	context_free (struct rohc_decomp_ctxt *const context)
	Destroy one decompression context and the profile specific data associated with it.
static rohc_status_t	d_decode_header (struct rohc_decomp decomp, const struct rohc_buf rohc_packet, struct rohc_buf const uncomp_packet, struct rohc_buf const rcvd_feedback, struct rohc_decomp_stream const stream)
	Decompress the compressed headers.
static bool	rohc_decomp_decode_cid (struct rohc_decomp decomp, const uint8_t packet, unsigned int len, rohc_cid_t const cid, size_t const add_cid_len, size_t *const large_cid_len)
	Decode the CID of a packet.
static void	rohc_decomp_parse_padding (const struct rohc_decomp const decomp, struct rohc_buf const packet)
	Parse padding bits if some are present.
static rohc_status_t	rohc_decomp_find_context (struct rohc_decomp const decomp, const uint8_t const packet, const size_t packet_len, const rohc_cid_type_t cid, const size_t large_cid_len, const struct rohc_ts arrival_time, rohc_profile_t const profile_id, struct rohc_decomp_ctxt const context, bool const context_created)
	Find the context for the given ROHC packet.
static rohc_status_t	rohc_decomp_decode_pkt (struct rohc_decomp const decomp, struct rohc_decomp_ctxt const context, const struct rohc_buf rohc_packet, const size_t add_cid_len, const size_t large_cid_len, struct rohc_buf const uncomp_packet, rohc_packet_t const packet_type, bool *const do_change_mode)
	Decode one ROHC packet.
static bool	rohc_decomp_check_ir_crc (const struct rohc_decomp const decomp, const struct rohc_decomp_ctxt const context, const uint8_t *const rohc_hdr, const size_t rohc_hdr_len, const size_t add_cid_len, const size_t large_cid_len, const uint8_t crc_packet)
	Check whether the CRC on IR or IR-DYN header is correct or not.
static void	rohc_decomp_stats_add_success (struct rohc_decomp_ctxt *const context, const size_t comp_hdr_len, const size_t uncomp_hdr_len)
	Update statistics upon successful decompression.
static void	rohc_decomp_update_context (struct rohc_decomp_ctxt const context, const void const decoded, const size_t payload_len, const struct rohc_ts pkt_arrival_time, bool *const do_change_mode)
	Update context with decoded values.
static bool	rohc_decomp_parse_feedbacks (struct rohc_decomp const decomp, struct rohc_buf const rohc_data, struct rohc_buf *const feedbacks)
	Parse zero or more feedback items from the given ROHC data.
static bool	rohc_decomp_parse_feedback (struct rohc_decomp const decomp, struct rohc_buf const rohc_data, struct rohc_buf const feedback, size_t const feedback_len)
	Parse a feedback item from the given ROHC data.
static bool	rohc_decomp_feedback_ack (struct rohc_decomp const decomp, const struct rohc_decomp_stream const infos, struct rohc_buf *const feedback)
	Build a positive ACK feedback.
static bool	rohc_decomp_feedback_nack (struct rohc_decomp const decomp, const struct rohc_decomp_stream const infos, struct rohc_buf *const feedback)
	Build a negative ACK feedback.
static void	rohc_decomp_reset_stats (struct rohc_decomp *const decomp)
	Reset all the statistics of the given ROHC decompressor.
static bool	rohc_decomp_packet_carry_static_info (const rohc_packet_t packet_type)
	Does packet type carry static information?
static bool	rohc_decomp_packet_carry_crc_7_or_8 (const rohc_packet_t packet_type)
	Does packet type carry 7- or 8-bit CRC?
struct rohc_decomp *	rohc_decomp_new2 (const rohc_cid_type_t cid_type, const rohc_cid_t max_cid, const rohc_mode_t mode)
	Create a new ROHC decompressor.
void	rohc_decomp_free (struct rohc_decomp *const decomp)
	Destroy the given ROHC decompressor.
rohc_status_t	rohc_decompress3 (struct rohc_decomp const decomp, const struct rohc_buf rohc_packet, struct rohc_buf const uncomp_packet, struct rohc_buf const rcvd_feedback, struct rohc_buf const feedback_send)
	Decompress the given ROHC packet into one uncompressed packet.
const char *	rohc_decomp_get_state_descr (const rohc_decomp_state_t state)
	Give a description for the given ROHC decompression context state.
bool	rohc_decomp_get_last_packet_info (const struct rohc_decomp const decomp, rohc_decomp_last_packet_info_t const info)
	Get some information about the last decompressed packet.
bool	rohc_decomp_get_context_info (const struct rohc_decomp const decomp, const rohc_cid_t cid, rohc_decomp_context_info_t const info)
	Get some information about the given decompression context.
bool	rohc_decomp_get_general_info (const struct rohc_decomp const decomp, rohc_decomp_general_info_t const info)
	Get some general information about the decompressor.
bool	rohc_decomp_get_cid_type (const struct rohc_decomp const decomp, rohc_cid_type_t const cid_type)
	Get the CID type that the decompressor uses.
bool	rohc_decomp_get_max_cid (const struct rohc_decomp const decomp, size_t const max_cid)
	Get the maximal CID value the decompressor uses.
bool	rohc_decomp_set_mrru (struct rohc_decomp *const decomp, const size_t mrru)
	Set the Maximum Reconstructed Reception Unit (MRRU).
bool	rohc_decomp_get_mrru (const struct rohc_decomp const decomp, size_t const mrru)
	Get the Maximum Reconstructed Reception Unit (MRRU).
bool	rohc_decomp_set_prtt (struct rohc_decomp *const decomp, const size_t prtt)
	Set the number of packets sent during one Round-Trip Time (RTT).
bool	rohc_decomp_get_prtt (const struct rohc_decomp const decomp, size_t const prtt)
	Get the number of packets sent during one Round-Trip Time (RTT).
bool	rohc_decomp_set_rate_limits (struct rohc_decomp *const decomp, const size_t k, const size_t n, const size_t k_1, const size_t n_1, const size_t k_2, const size_t n_2)
	Set the rate limits for feedbacks.
bool	rohc_decomp_get_rate_limits (const struct rohc_decomp const decomp, size_t const k, size_t const n, size_t const k_1, size_t const n_1, size_t const k_2, size_t *const n_2)
	Get the rate limits for feedbacks currently configured.
bool	rohc_decomp_set_features (struct rohc_decomp *const decomp, const rohc_decomp_features_t features)
	Enable/disable features for ROHC decompressor.
bool	rohc_decomp_profile_enabled (const struct rohc_decomp *const decomp, const rohc_profile_t profile)
	Is the given decompression profile enabled for a decompressor?
bool	rohc_decomp_enable_profile (struct rohc_decomp *const decomp, const rohc_profile_t profile)
	Enable a decompression profile for a decompressor.
bool	rohc_decomp_disable_profile (struct rohc_decomp *const decomp, const rohc_profile_t profile)
	Disable a decompression profile for a decompressor.
bool	rohc_decomp_enable_profiles (struct rohc_decomp *const decomp,...)
	Enable several decompression profiles for a decompressor.
bool	rohc_decomp_disable_profiles (struct rohc_decomp *const decomp,...)
	Disable several decompression profiles for a decompressor.
bool	rohc_decomp_set_traces_cb2 (struct rohc_decomp decomp, rohc_trace_callback2_t callback, void const priv_ctxt)
	Set the callback function used to manage traces in decompressor.
Variables
struct rohc_decomp_profile d_uncomp_profile d_udp_profile d_ip_profile d_udplite_profile d_esp_profile d_rtp_profile	d_tcp_profile
	Define the decompression part of the TCP profile as described in the RFC 3095.
static struct rohc_decomp_profile *const	rohc_decomp_profiles [D_NUM_PROFILES]
	The decompression parts of the ROHC profiles.

Detailed Description

ROHC decompression routines.

Author:: Didier Barvaux <didier.barvaux@toulouse.viveris.com>; Didier Barvaux <didier@barvaux.org>; David Moreau from TAS

Function Documentation

static struct rohc_decomp_ctxt * context_create	(	struct rohc_decomp *	decomp,
		const rohc_cid_t	cid,
		const struct rohc_decomp_profile *const	profile,
		const struct rohc_ts	arrival_time
	)			`[static, read]`

Create one new decompression context with profile specific data.

Parameters:

	decomp	The ROHC decompressor
	cid	The CID of the new context
	profile	The profile to be assigned with the new context
	arrival_time	The time at which packet was received (0 if unknown, or to disable time-related features in ROHC protocol)

Returns:: The new context if successful, NULL otherwise

static void context_free ( struct rohc_decomp_ctxt *const context ) [static]

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

Parameters:

context

The context to destroy

static rohc_status_t d_decode_header	(	struct rohc_decomp *	decomp,
		const struct rohc_buf	rohc_packet,
		struct rohc_buf *const	uncomp_packet,
		struct rohc_buf *const	rcvd_feedback,
		struct rohc_decomp_stream *const	stream
	)			`[static]`

Decompress the compressed headers.

Parameters:

	decomp	The ROHC decompressor
	rohc_packet	The ROHC packet to decode
`[out]`	uncomp_packet	The uncompressed packet
`[out]`	rcvd_feedback	The feedback received from the remote peer for the same-side associated ROHC compressor through the feedback channel: If NULL, ignore the received feedback data If not NULL, store the received feedback in at the given address
`[out]`	stream	The informations about the decompressed stream, required for sending feedback to compressor

Returns:

Possible return values:

ROHC_STATUS_OK if packet is successfully decoded,
ROHC_STATUS_NO_CONTEXT if no matching context was found and packet cannot create a new context (or failed to do so),
ROHC_STATUS_MALFORMED if packet is malformed,
ROHC_STATUS_BAD_CRC if a CRC error occurs,
ROHC_STATUS_ERROR if another error occurs

static struct rohc_decomp_ctxt * find_context	(	const struct rohc_decomp *const	decomp,
		const rohc_cid_t	cid
	)			`[static, 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

static struct rohc_decomp_profile * find_profile	(	const struct rohc_decomp *const	decomp,
		const rohc_profile_t	profile_id
	)			`[static, read]`

Find the ROHC profile with the given profile ID.

Parameters:

	decomp	The ROHC decompressor
	profile_id	The profile ID to search for

Returns:: The matching ROHC profile if found and enabled, NULL if not found or disabled

static bool rohc_decomp_check_ir_crc	(	const struct rohc_decomp *const	decomp,
		const struct rohc_decomp_ctxt *const	context,
		const uint8_t *const	rohc_hdr,
		const size_t	rohc_hdr_len,
		const size_t	add_cid_len,
		const size_t	large_cid_len,
		const uint8_t	crc_packet
	)			`[static]`

Check whether the CRC on IR or IR-DYN header is correct or not.

The CRC for IR/IR-DYN headers is always CRC-8. It is computed on the whole compressed header (payload excluded, but any CID bits included).

Parameters:

	decomp	The ROHC decompressor
	context	The decompression context
	rohc_hdr	The compressed IR or IR-DYN header
	rohc_hdr_len	The length (in bytes) of the compressed header
	add_cid_len	The length of the optional Add-CID field
	large_cid_len	The length of the optional large CID field
	crc_packet	The CRC extracted from the ROHC header

Returns:: true if the CRC is correct, false otherwise

static bool rohc_decomp_create_contexts	(	struct rohc_decomp *const	decomp,
		const rohc_cid_t	max_cid
	)			`[static]`

Create the array of decompression contexts.

The maximum size of the array is ROHC_LARGE_CID_MAX + 1.

Parameters:

	decomp	The ROHC decompressor
	max_cid	The MAX_CID value to used

Returns:: true if the contexts were created, false otherwise

static bool rohc_decomp_decode_cid	(	struct rohc_decomp *	decomp,
		const uint8_t *	packet,
		unsigned int	len,
		rohc_cid_t *const	cid,
		size_t *const	add_cid_len,
		size_t *const	large_cid_len
	)			`[static]`

Decode the CID of a packet.

Parameters:

	decomp	The ROHC decompressor
	packet	The ROHC packet to extract CID from
	len	The size of the ROHC packet
`[out]`	cid	The Context ID (CID) extracted from the ROHC packet
`[out]`	add_cid_len	The length of add-CID in ROHC packet
`[out]`	large_cid_len	The length of large CID in ROHC packet

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

static rohc_status_t rohc_decomp_decode_pkt	(	struct rohc_decomp *const	decomp,
		struct rohc_decomp_ctxt *const	context,
		const struct rohc_buf	rohc_packet,
		const size_t	add_cid_len,
		const size_t	large_cid_len,
		struct rohc_buf *const	uncomp_packet,
		rohc_packet_t *const	packet_type,
		bool *const	do_change_mode
	)			`[static]`

Decode one ROHC packet.

Steps:

A. Parse the ROHC header
B. For IR and IR-DYN packet, check for correct compressed header (CRC)
C. Decode extracted bits
D. Build uncompressed headers (and check for correct decompression for UO* packets)
E. Copy the payload (if any)
F. Update the compression context

Steps C and D may be repeated if packet or context repair is attempted upon CRC failure.

Parameters:

	decomp	The ROHC decompressor
	context	The decompression context
	rohc_packet	The ROHC packet to decode
	add_cid_len	The length of the optional Add-CID field
	large_cid_len	The length of the optional large CID field
`[out]`	uncomp_packet	The uncompressed packet
`[in,out]`	packet_type	IN: The type of the ROHC packet to parse OUT: The type of the parsed ROHC packet
`[out]`	do_change_mode	Whether the profile context wants to change its operational mode or not

Returns:: ROHC_STATUS_OK if packet is successfully decoded, ROHC_STATUS_MALFORMED if packet is malformed, ROHC_STATUS_BAD_CRC if a CRC error occurs, ROHC_STATUS_ERROR if an error occurs

static bool rohc_decomp_feedback_ack	(	struct rohc_decomp *const	decomp,
		const struct rohc_decomp_stream *const	infos,
		struct rohc_buf *const	feedback
	)			`[static]`

Build a positive ACK feedback.

Parameters:

	decomp	The ROHC decompressor
	infos	The information collected on the successfully decompressed packet
`[out]`	feedback	The feedback to be transmitted to the remote compressor through the feedback channel

Returns:: true if the ACK feedback was successfully built (may be 0 byte), false if a problem occurred

static bool rohc_decomp_feedback_nack	(	struct rohc_decomp *const	decomp,
		const struct rohc_decomp_stream *const	infos,
		struct rohc_buf *const	feedback
	)			`[static]`

Build a negative ACK feedback.

There are two types of negative feedback: NACK and STATIC-NACK.

Parameters:

	decomp	The ROHC decompressor
	infos	The information collected on the failed decompressed packet
`[out]`	feedback	The feedback to be transmitted to the remote compressor through the feedback channel (may be NULL)

Returns:: true if the ACK feedback was successfully built (may be 0 byte), false if a problem occurred

static rohc_status_t rohc_decomp_find_context	(	struct rohc_decomp *const	decomp,
		const uint8_t *const	packet,
		const size_t	packet_len,
		const rohc_cid_type_t	cid,
		const size_t	large_cid_len,
		const struct rohc_ts	arrival_time,
		rohc_profile_t *const	profile_id,
		struct rohc_decomp_ctxt **const	context,
		bool *const	context_created
	)			`[static]`

Find the context for the given ROHC packet.

If packet is an IR(-DYN) packet, parse it for the profile ID. Searche for the context with the given CID. Create a new context if needed.

Parameters:

	decomp	The ROHC decompressor
	packet	The ROHC packet to parse
	packet_len	The length (in bytes) of the ROHC packet
	cid	The CID that was parsed from ROHC packet
	large_cid_len	The length (in bytes) of the Large CID that was parsed from ROHC packet
	arrival_time	The time at which the ROHC packet was received
`[out]`	profile_id	The profile ID parsed from the ROHC packet
`[out]`	context	The decompression context for the given ROHC packet
`[out]`	context_created	Whether the packet has just been created or not

Returns:

Possible return values:

ROHC_STATUS_OK if context was found,
ROHC_STATUS_NO_CONTEXT if no matching context was found and packet cannot create a new context (or failed to do so),
ROHC_STATUS_MALFORMED if packet is malformed

static bool rohc_decomp_packet_carry_crc_7_or_8 ( const rohc_packet_t packet_type ) [static]

Does packet type carry 7- or 8-bit CRC?

Parameters:

packet_type

The type of packet

Returns:: true if packet carries 7- or 8-bit CRC, false if it does not

static bool rohc_decomp_packet_carry_static_info ( const rohc_packet_t packet_type ) [static]

Does packet type carry static information?

Parameters:

packet_type

The type of packet

Returns:: true if packet carries static information, false if it does not

static bool rohc_decomp_parse_feedback	(	struct rohc_decomp *const	decomp,
		struct rohc_buf *const	rohc_data,
		struct rohc_buf *const	feedback,
		size_t *const	feedback_len
	)			`[static]`

Parse a feedback item from the given ROHC data.

Parameters:

	decomp	The ROHC decompressor
	rohc_data	The ROHC data to parse for one feedback item
`[out]`	feedback	The retrieved feedback (header and data included), may be NULL if one don't want to retrieve the feedback item
`[out]`	feedback_len	The length of the parsed feedback (maybe be different from feedback->len if feedback was NULL or full)

Returns:: true if feedback parsing was successful, false if feedback is malformed

static bool rohc_decomp_parse_feedbacks	(	struct rohc_decomp *const	decomp,
		struct rohc_buf *const	rohc_data,
		struct rohc_buf *const	feedbacks
	)			`[static]`

Parse zero or more feedback items from the given ROHC data.

Parameters:

	decomp	The ROHC decompressor
	rohc_data	The ROHC data to parse for feedback items
`[out]`	feedbacks	The parsed feedback items, may be NULL if one don't want to retrieve the feedback items

Returns:: true if parsing of feedback items is successful, false if at least one feedback is malformed

static void rohc_decomp_parse_padding	(	const struct rohc_decomp *const	decomp,
		struct rohc_buf *const	packet
	)			`[static]`

Parse padding bits if some are present.

Parameters:

	decomp	The ROHC decompressor
	packet	The ROHC packet to parse

static void rohc_decomp_reset_stats ( struct rohc_decomp *const decomp ) [static]

Reset all the statistics of the given ROHC decompressor.

Parameters:

decomp

The ROHC decompressor

static void rohc_decomp_stats_add_success	(	struct rohc_decomp_ctxt *const	context,
		const size_t	comp_hdr_len,
		const size_t	uncomp_hdr_len
	)			`[static]`

Update statistics upon successful decompression.

Parameters:

	context	The decompression context
	comp_hdr_len	The length (in bytes) of the compressed header
	uncomp_hdr_len	The length (in bytes) of the uncompressed header

static void rohc_decomp_update_context	(	struct rohc_decomp_ctxt *const	context,
		const void *const	decoded,
		const size_t	payload_len,
		const struct rohc_ts	pkt_arrival_time,
		bool *const	do_change_mode
	)			`[static]`

Update context with decoded values.

Parameters:

	context	The decompression context
	decoded	The decoded values to update in the context
	payload_len	The length of the packet payload
	pkt_arrival_time	The arrival time of the decoded ROHC packet
`[out]`	do_change_mode	Whether the context wants to change its operational mode or not

Variable Documentation

struct rohc_decomp_profile d_uncomp_profile d_udp_profile d_ip_profile d_udplite_profile d_esp_profile d_rtp_profile d_tcp_profile

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

struct rohc_decomp_profile* const rohc_decomp_profiles[D_NUM_PROFILES] [static]

Initial value:

{
        &d_uncomp_profile,
        &d_rtp_profile,
        &d_udp_profile,
        &d_esp_profile,
        &d_ip_profile,
        &d_tcp_profile,
        &d_udplite_profile,
}

The decompression parts of the ROHC profiles.

rohc_decomp.c File Reference

Data Structures

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation