rohc_comp.c File Reference

ROHC compression routines. More...

#include "rohc_comp.h"
#include "rohc_traces.h"
#include "rtp.h"
#include <stdbool.h>
#include <assert.h>

Include dependency graph for rohc_comp.c:

Functions
void	c_destroy_contexts (struct rohc_comp *comp)
	Destroy all the compression contexts in the context array.
int	c_create_contexts (struct rohc_comp *comp)
	Create the array of compression contexts.
int	c_alloc_contexts (struct rohc_comp *comp, int size)
	Allocate memory for the array of compression contexts.
struct rohc_comp *	rohc_alloc_compressor (int max_cid, int jam_use, int adapt_size, int encap_size)
	Create one ROHC compressor.
void	rohc_free_compressor (struct rohc_comp *comp)
	Destroy one ROHC compressor.
int	rohc_compress (struct rohc_comp *comp, unsigned char *ibuf, int isize, unsigned char *obuf, int osize)
	Compress a ROHC packet.
void	rohc_activate_profile (struct rohc_comp *comp, int profile)
	Activate a profile for a compressor.
int	rohc_c_using_small_cid (struct rohc_comp *comp)
	Whether the compressor uses small CID or not.
void	rohc_c_set_header (struct rohc_comp *comp, int header)
	Set the maximal header size. The maximal header size is ignored for the moment.
void	rohc_c_set_mrru (struct rohc_comp *comp, int value)
	Set the Maximum Reconstructed Reception Unit (MRRU). The MRRU is ignored for the moment.
void	rohc_c_set_max_cid (struct rohc_comp *comp, int value)
	Set the maximal CID value the compressor should use.
void	rohc_c_set_large_cid (struct rohc_comp *comp, int large_cid)
	Tell the compressor to use large CIDs.
void	rohc_c_set_enable (struct rohc_comp *comp, int enable)
	Enable the ROHC compressor.
int	rohc_c_is_enabled (struct rohc_comp *comp)
	Whether the ROHC compressor is enabled or not.
int	rohc_c_info (char *buffer)
	Get information about available compression profiles.
int	rohc_c_statistics (struct rohc_comp *comp, unsigned int indent, char *buffer)
	Get information about a ROHC compressor.
int	rohc_c_context (struct rohc_comp *comp, int cid, unsigned int indent, char *buffer)
	Get information about a compression context.
struct c_profile *	c_get_profile_from_id (struct rohc_comp *comp, int profile_id)
	Find out a ROHC profile given a profile ID.
boolean	c_is_in_list (struct c_profile *profile, int port)
	Check whether an UDP port is associated with a given profile or not.
struct c_profile *	c_get_profile_from_packet (struct rohc_comp *comp, struct ip_packet *outer_ip, struct ip_packet *inner_ip, int protocol)
	Find out a ROHC profile given an IP protocol ID.
struct c_context *	c_create_context (struct rohc_comp *comp, struct c_profile *profile, struct ip_packet ip)
	Create a compression context.
struct c_context *	c_find_context (struct rohc_comp *comp, struct c_profile *profile, struct ip_packet ip)
	Find a compression context given a profile and an IP packet.
struct c_context *	c_get_context (struct rohc_comp *comp, int cid)
	Find out a context given its CID.
void	c_piggyback_feedback (struct rohc_comp *comp, unsigned char *feedback, int size)
	Add a feedback packet to the next outgoing ROHC packet (piggybacking)
int	rohc_feedback_flush (struct rohc_comp *comp, unsigned char *obuf, int osize)
	Send as much feedback data as possible.
void	c_deliver_feedback (struct rohc_comp *comp, unsigned char *packet, int size)
	Callback called by a decompressor to deliver a feedback packet to the compressor.
Variables
struct c_profile c_rtp_profile c_udp_profile c_udp_lite_profile c_ip_profile	c_uncompressed_profile
	Define the compression part of the Uncompressed profile as described in the RFC 3095.
struct c_profile *	c_profiles [C_NUM_PROFILES]
	The compression parts of the ROHC profiles.

---

Detailed Description

ROHC compression routines.

Author:

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

The hackers from ROHC for Linux

David Moreau from TAS

---

Function Documentation

int c_alloc_contexts	(	struct rohc_comp *	comp,
		int	size
	)

Allocate memory for the array of compression contexts.

Parameters:

comp	The ROHC compressor
size	The size of the context array (maximum: comp->medium.max_cid + 1)

Returns:

1 if the creation is successful, 0 otherwise

References c_create_wlsb(), rohc_comp::contexts, c_context::header_16_compressed, c_context::header_16_uncompressed, medium::max_cid, rohc_comp::medium, rohc_comp::num_contexts, rohc_debugf, c_context::total_16_compressed, c_context::total_16_uncompressed, and zfree.

Referenced by c_create_context(), and c_create_contexts().

struct c_context* c_create_context	(	struct rohc_comp *	comp,
		struct c_profile *	profile,
		struct ip_packet	ip
	)		[read]

Create a compression context.

Parameters:

comp	The ROHC compressor
profile	The profile to associate the context with
ip	The IP packet to initialize the context

Returns:

The compression context if successful, NULL otherwise

References c_alloc_contexts(), c_context::cid, c_context::compressor, rohc_comp::contexts, c_profile::create, c_profile::destroy, c_context::first_used, c_context::header_compressed_size, c_context::header_last_compressed_size, c_context::header_last_uncompressed_size, c_context::header_uncompressed_size, IR, c_context::latest_used, c_context::mode, rohc_comp::num_contexts, rohc_comp::num_contexts_used, c_context::num_recv_feedbacks, c_context::num_sent_ir, c_context::num_sent_ir_dyn, c_context::num_sent_packets, c_context::profile, rohc_debugf, c_context::state, c_context::total_compressed_size, c_context::total_last_compressed_size, c_context::total_last_uncompressed_size, c_context::total_uncompressed_size, U_MODE, and c_context::used.

Referenced by rohc_compress().

int c_create_contexts

(

struct rohc_comp *

comp

)

Create the array of compression contexts.

Parameters:

comp	The ROHC compressor

Returns:

1 if the creation is successful, 0 otherwise

References c_alloc_contexts(), rohc_comp::contexts, rohc_comp::num_contexts, and rohc_comp::num_contexts_used.

Referenced by rohc_alloc_compressor().

void c_deliver_feedback	(	struct rohc_comp *	comp,
		unsigned char *	packet,
		int	size
	)

Callback called by a decompressor to deliver a feedback packet to the compressor.

When feedback is received by the decompressor, this function is called and delivers the feedback to the right profile/context of the compressor.

Parameters:

comp	The ROHC compressor
packet	The feedback data
size	The length of the feedback packet

References c_feedback::acktype, c_get_context(), c_feedback::cid, medium::cid_type, d_decode_add_cid(), d_is_add_cid(), d_sdvalue_decode(), d_sdvalue_size(), c_feedback::data, c_profile::feedback, rohc_comp::medium, c_context::num_recv_feedbacks, c_context::profile, rohc_debugf, c_feedback::size, c_feedback::specific_offset, c_feedback::specific_size, c_feedback::type, and zfree.

void c_destroy_contexts

(

struct rohc_comp *

comp

)

Destroy all the compression contexts in the context array.

The profile-specific contexts are also destroyed.

Parameters:

comp	The ROHC compressor

References c_destroy_wlsb(), rohc_comp::contexts, c_profile::destroy, c_context::header_16_compressed, c_context::header_16_uncompressed, rohc_comp::num_contexts, rohc_comp::num_contexts_used, c_context::profile, c_context::total_16_compressed, c_context::total_16_uncompressed, c_context::used, and zfree.

Referenced by rohc_free_compressor().

struct c_context* c_find_context	(	struct rohc_comp *	comp,
		struct c_profile *	profile,
		struct ip_packet	ip
	)		[read]

Find a compression context given a profile and an IP packet.

Parameters:

comp	The ROHC compressor
profile	The profile the context must be associated with
ip	The IP packet that must be accepted by the context

Returns:

The compression context if found, NULL if not found, -1 if an error occurs

References c_profile::check_context, c_context::cid, rohc_comp::contexts, c_profile::id, rohc_comp::num_contexts, c_context::profile, rohc_debugf, and c_context::used.

Referenced by rohc_compress().

struct c_context* c_get_context	(	struct rohc_comp *	comp,
		int	cid
	)		[read]

Find out a context given its CID.

Parameters:

comp	The ROHC compressor
cid	The CID of the context to find

Returns:

The context with the given CID if found, NULL otherwise

References c_context::cid, rohc_comp::contexts, rohc_comp::num_contexts, and c_context::used.

Referenced by c_deliver_feedback().

struct c_profile* c_get_profile_from_id	(	struct rohc_comp *	comp,
		int	profile_id
	)		[read]

Find out a ROHC profile given a profile ID.

Parameters:

comp	The ROHC compressor
profile_id	The ID of the ROHC profile to find out

Returns:

The ROHC profile if found, NULL otherwise

References C_NUM_PROFILES, and rohc_comp::profiles.

Referenced by rohc_compress().

struct c_profile* c_get_profile_from_packet	(	struct rohc_comp *	comp,
		struct ip_packet *	outer_ip,
		struct ip_packet *	inner_ip,
		int	protocol
	)		[read]

Find out a ROHC profile given an IP protocol ID.

Parameters:

comp	The ROHC compressor
outer_ip	The outer IP header of the network packet that will help choosing the best profile
inner_ip	The inner IP header of the network packet that will help choosing the best profile if any NULL if there is no inner IP header in the packet
protocol	The transport protocol of the network packet

Returns:

The ROHC profile if found, NULL otherwise

References c_is_in_list(), C_NUM_PROFILES, c_profile::description, ip_get_hdrlen(), ip_get_next_layer(), ip_get_plen(), ip_is_fragment(), IPV4, IPV6, rohc_comp::profiles, rohc_debugf, ROHC_PROFILE_RTP, ROHC_PROFILE_UNCOMPRESSED, and ip_packet::version.

Referenced by rohc_compress().

boolean c_is_in_list	(	struct c_profile *	profile,
		int	port
	)

Check whether an UDP port is associated with a given profile or not.

Parameters:

profile	The ROHC profile
port	The UDP port

Returns:

ROHC_TRUE if UDP is associated with profile, ROHC_FALSE otherwise

References c_profile::ports, and ROHC_FALSE.

Referenced by c_get_profile_from_packet().

void c_piggyback_feedback	(	struct rohc_comp *	comp,
		unsigned char *	feedback,
		int	size
	)

Add a feedback packet to the next outgoing ROHC packet (piggybacking)

Parameters:

comp	The ROHC compressor
feedback	The feedback data
size	The length of the feedback packet

References rohc_feedback::data, FEEDBACK_BUFFER_SIZE, rohc_comp::feedbacks, rohc_comp::feedbacks_first, rohc_comp::feedbacks_next, rohc_feedback::length, and rohc_debugf.

Referenced by d_change_mode_feedback(), and d_optimistic_feedback().

int rohc_c_context	(	struct rohc_comp *	comp,
		int	cid,
		unsigned int	indent,
		char *	buffer
	)

Get information about a compression context.

This function outputs XML.

Parameters:

comp	The ROHC compressor
cid	The CID of the compressor context to output information about
indent	The indent level to beautify the XML output
buffer	The buffer where to store the information

Returns:

The length of the data stored in the buffer if successful, -2 if the given CID is too large, -1 if the given CID is unused or an error occurs

References c_mean_wlsb(), c_sum_wlsb(), c_context::cid, rohc_comp::contexts, c_profile::description, c_context::first_used, c_context::header_16_compressed, c_context::header_16_uncompressed, c_context::header_compressed_size, c_context::header_uncompressed_size, c_context::latest_used, c_context::mode, rohc_comp::num_contexts, c_context::num_recv_feedbacks, c_context::num_sent_ir, c_context::num_sent_ir_dyn, c_context::num_sent_packets, c_context::profile, c_context::state, c_context::total_16_compressed, c_context::total_16_uncompressed, c_context::total_compressed_size, c_context::total_uncompressed_size, and c_context::used.

Referenced by rohc_c_statistics().

---

Variable Documentation

struct c_profile* c_profiles[C_NUM_PROFILES]

Initial value:

{
        &c_rtp_profile,
        &c_udp_profile,
        &c_udp_lite_profile,
        &c_ip_profile,
        &c_uncompressed_profile,
}

The compression parts of the ROHC profiles.

struct c_profile c_rtp_profile c_udp_profile c_udp_lite_profile c_ip_profile c_uncompressed_profile

Define the compression part of the Uncompressed profile as described in the RFC 3095.