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. More...

static const 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. More...

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. More...

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. More...

static void	context_free (struct rohc_decomp_ctxt *const context)
	Destroy one decompression context and the profile specific data associated with it. More...

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. More...

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. More...

static void	rohc_decomp_parse_padding (const struct rohc_decomp const decomp, struct rohc_buf const packet)
	Parse padding bits if some are present. More...

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. More...

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. More...

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. More...

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. More...

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. More...

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. More...

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. More...

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. More...

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. More...

static void	rohc_decomp_reset_stats (struct rohc_decomp *const decomp)
	Reset all the statistics of the given ROHC decompressor. More...

static bool	rohc_decomp_packet_carry_static_info (const rohc_packet_t packet_type)
	Does packet type carry static information? More...

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? More...

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. More...

void	rohc_decomp_free (struct rohc_decomp *const decomp)
	Destroy the given ROHC decompressor. More...

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. More...

const char *	rohc_decomp_get_state_descr (const rohc_decomp_state_t state)
	Give a description for the given ROHC decompression context state. More...

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. More...

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. More...

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. More...

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. More...

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. More...

bool	rohc_decomp_set_mrru (struct rohc_decomp *const decomp, const size_t mrru)
	Set the Maximum Reconstructed Reception Unit (MRRU). More...

bool	rohc_decomp_get_mrru (const struct rohc_decomp const decomp, size_t const mrru)
	Get the Maximum Reconstructed Reception Unit (MRRU). More...

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). More...

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). More...

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. More...

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. More...

bool	rohc_decomp_set_features (struct rohc_decomp *const decomp, const rohc_decomp_features_t features)
	Enable/disable features for ROHC decompressor. More...

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? More...

bool	rohc_decomp_enable_profile (struct rohc_decomp *const decomp, const rohc_profile_t profile)
	Enable a decompression profile for a decompressor. More...

bool	rohc_decomp_disable_profile (struct rohc_decomp *const decomp, const rohc_profile_t profile)
	Disable a decompression profile for a decompressor. More...

bool	rohc_decomp_enable_profiles (struct rohc_decomp *const decomp,...)
	Enable several decompression profiles for a decompressor. More...

bool	rohc_decomp_disable_profiles (struct rohc_decomp *const decomp,...)
	Disable several decompression profiles for a decompressor. More...

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. More...

Variables
const 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. More...

static const struct rohc_decomp_profile *const	rohc_decomp_profiles [D_NUM_PROFILES]
	The decompression parts of the ROHC profiles. More...

Detailed Description

ROHC decompression 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; 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

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

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 const struct rohc_decomp_profile * find_profile	(	const struct rohc_decomp *const	decomp,
		const rohc_profile_t	profile_id
	)

static

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

const 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.

const 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.

Data Structures

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation