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

#include "rohc_comp_internals.h"
#include "rohc_packets.h"
#include "schemes/list.h"
#include "ip.h"
#include "crc.h"
#include <stdlib.h>

Include dependency graph for c_generic.h:

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Data Structures
struct	ipv4_header_info
	Store information about an IPv4 header between the different compressions of IP packets. More...
struct	ipv6_header_info
	Store information about an IPv6 header between the different compressions of IP packets. More...
struct	ip_header_info
	Store information about an IP (IPv4 or IPv6) header between the different compressions of IP packets. More...
struct	generic_tmp_vars
	Structure that contains variables that are used during one single compression of packet. More...
struct	c_generic_context
	The generic compression context. More...
Functions
bool	c_generic_create (struct rohc_comp_ctxt const context, const rohc_lsb_shift_t sn_shift, const struct net_pkt const packet)
	Create a new context and initialize it thanks to the given IP packet.
void	c_generic_destroy (struct rohc_comp_ctxt *const context)
	Destroy the context.
bool	c_generic_check_profile (const struct rohc_comp const comp, const struct net_pkt const packet)
	Check if the given packet corresponds to an IP-based profile.
void	change_state (struct rohc_comp_ctxt *const context, const rohc_comp_state_t new_state)
	Change the state of the context.
rohc_ext_t	decide_extension (const struct rohc_comp_ctxt *const context)
	Decide what extension shall be used in the UO-1-ID/UOR-2 packet.
int	c_generic_encode (struct rohc_comp_ctxt const context, const struct net_pkt const uncomp_pkt, unsigned char const rohc_pkt, const size_t rohc_pkt_max_len, rohc_packet_t const packet_type, size_t *const payload_offset)
	Encode an IP packet according to a pattern decided by several different factors.
bool	c_generic_reinit_context (struct rohc_comp_ctxt *const context)
	Re-initialize the given context.
bool	c_generic_feedback (struct rohc_comp_ctxt const context, const struct c_feedback const feedback)
	Update the profile when feedback is received.
bool	c_generic_use_udp_port (const struct rohc_comp_ctxt *const context, const unsigned int port)
	Whether the profile uses the given UDP port.
void	decide_state (struct rohc_comp_ctxt *const context)
	Decide the state that should be used for the next packet.
void	rohc_get_ipid_bits (const struct rohc_comp_ctxt const context, size_t const nr_innermost_bits, size_t *const nr_outermost_bits)
	Get the number of non-random outer/inner IP-ID bits.

Detailed Description

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

Author:: Didier Barvaux <didier.barvaux@toulouse.viveris.com>; Didier Barvaux <didier@barvaux.org>

Function Documentation

bool c_generic_check_profile	(	const struct rohc_comp *const	comp,
		const struct net_pkt *const	packet
	)

Check if the given packet corresponds to an IP-based profile.

Conditions are:

the version of the outer IP header is 4 or 6
if the outer IP header is IPv4, it does not contain options
the outer IP header is not an IP fragment
if there are at least 2 IP headers, the version of the inner IP header is 4 or 6
if there are at least 2 IP headers and if the inner IP header is IPv4, it does not contain options
if there are at least 2 IP headers, the inner IP header is not an IP fragment

This function is one of the functions that must exist in one profile for the framework to work.

Parameters:

comp	The ROHC compressor
packet	The packet to check

Returns:

Whether the IP packet corresponds to the profile:

true if the IP packet corresponds to the profile,
false if the IP packet does not correspond to the profile

bool c_generic_create	(	struct rohc_comp_ctxt *const	context,
		const rohc_lsb_shift_t	sn_shift,
		const struct net_pkt *const	packet
	)

Create a new context and initialize it thanks to the given IP packet.

Parameters:

context	The compression context
sn_shift	The shift parameter (p) to use for encoding SN with W-LSB
packet	The packet given to initialize the new context

Returns:: bool if successful, false otherwise

void c_generic_destroy ( struct rohc_comp_ctxt *const 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

int c_generic_encode	(	struct rohc_comp_ctxt *const	context,
		const struct net_pkt *const	uncomp_pkt,
		unsigned char *const	rohc_pkt,
		const size_t	rohc_pkt_max_len,
		rohc_packet_t *const	packet_type,
		size_t *const	payload_offset
	)

Encode an IP packet according to a pattern decided by several different factors.

1. parse uncompressed packet (done in rohc_compress3)
2. detect changes between the new uncompressed packet and the context
3. decide new compressor state
4. determine how many bytes are required for every field
5. decide which packet to send
6. code the ROHC header
7. copy the packet payload (done in rohc_compress3)
8. update the context with the new headers

This function is one of the functions that must exist in one profile for the framework to work.

Parameters:

context	The compression context
uncomp_pkt	The uncompressed packet to encode
rohc_pkt	OUT: The ROHC packet
rohc_pkt_max_len	The maximum length of the ROHC packet
packet_type	OUT: The type of ROHC packet that is created
payload_offset	OUT: The offset for the payload in the IP packet

Returns:: The length of the ROHC packet if successful, -1 otherwise

bool c_generic_feedback	(	struct rohc_comp_ctxt *const	context,
		const struct c_feedback *const	feedback
	)

Update the profile when feedback is received.

This function is one of the functions that must exist in one profile for the framework to work.

Parameters:

context	The compression context
feedback	The feedback information

Returns:: true if the feedback was successfully handled, false if the feedback could not be taken into account

bool c_generic_reinit_context ( struct rohc_comp_ctxt *const context )

Re-initialize the given context.

Make the context restart its initialization with decompressor, ie. it goes in the lowest compression state.

Parameters:

context The compression context to re-initialize

Returns:: true in case of success, false otherwise

bool c_generic_use_udp_port	(	const struct rohc_comp_ctxt *const	context,
		const unsigned int	port
	)

Whether the profile uses the given UDP port.

This function is one of the functions that must exist in one profile for the framework to work.

Parameters:

context	The compression context
port	The UDP port number to check

Returns:: always return true, it is used by non-RTP profiles

void change_state	(	struct rohc_comp_ctxt *const	context,
		const rohc_comp_state_t	new_state
	)

Change the state of the context.

Parameters:

context	The compression context
new_state	The new state the context must enter in

rohc_ext_t decide_extension ( const struct rohc_comp_ctxt *const context )

Decide what extension shall be used in the UO-1-ID/UOR-2 packet.

Extensions 0, 1 & 2 are IPv4 only because of the IP-ID.

Parameters:

context The compression context

Returns:: The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3 if successful, ROHC_EXT_UNKNOWN otherwise

void decide_state ( struct rohc_comp_ctxt *const context )

Decide the state that should be used for the next packet.

The three states are:

Initialization and Refresh (IR),
First Order (FO),
Second Order (SO).

Parameters:

context The compression context

void rohc_get_ipid_bits	(	const struct rohc_comp_ctxt *const	context,
		size_t *const	nr_innermost_bits,
		size_t *const	nr_outermost_bits
	)

Get the number of non-random outer/inner IP-ID bits.

Parameters:

context	The compression context
nr_innermost_bits	OUT: the maximum number of IP-ID bits for the innermost IPv4 header
nr_outermost_bits	OUT: the maximum number of IP-ID bits for the outermost IP header

Data Structures

Functions

Detailed Description

Function Documentation