c_udp.c File Reference

ROHC compression context for the UDP profile. More...

#include "c_udp.h"
#include "c_ip.h"
#include "rohc_traces_internal.h"
#include "rohc_packets.h"
#include "rohc_utils.h"
#include "crc.h"
#include "rohc_comp_rfc3095.h"
#include "protocols/udp.h"
#include <stdlib.h>
#include <string.h>
#include <assert.h>

Include dependency graph for c_udp.c:

Data Structures
struct	udp_tmp_vars
	Define the UDP-specific temporary variables in the profile compression context. More...
struct	sc_udp_context
	Define the UDP part of the profile decompression context. More...
Functions
static bool	c_udp_create (struct rohc_comp_ctxt const context, const struct net_pkt const packet)
	Create a new UDP context and initialize it thanks to the given IP/UDP packet.
static void	udp_decide_state (struct rohc_comp_ctxt *const context)
	Decide the state that should be used for the next packet compressed with the ROHC UDP profile.
static int	c_udp_encode (struct rohc_comp_ctxt const context, const struct net_pkt const uncomp_pkt, uint8_t const rohc_pkt, const size_t rohc_pkt_max_len, rohc_packet_t const packet_type, size_t *const payload_offset)
	Encode an IP/UDP packet according to a pattern decided by several different factors.
static size_t	udp_code_dynamic_udp_part (const struct rohc_comp_ctxt const context, const uint8_t const next_header, uint8_t *const dest, const size_t counter)
	Build the dynamic part of the UDP header.
static int	udp_changed_udp_dynamic (const struct rohc_comp_ctxt context, const struct udphdr udp)
	Check if the dynamic part of the UDP header changed.
bool	c_udp_check_profile (const struct rohc_comp const comp, const struct net_pkt const packet)
	Check if the given packet corresponds to the UDP profile.
bool	c_udp_check_context (const struct rohc_comp_ctxt const context, const struct net_pkt const packet)
	Check if the IP/UDP packet belongs to the context.
size_t	udp_code_uo_remainder (const struct rohc_comp_ctxt const context, const uint8_t const next_header, uint8_t *const dest, const size_t counter)
	Build UDP-related fields in the tail of the UO packets.
size_t	udp_code_static_udp_part (const struct rohc_comp_ctxt const context, const uint8_t const next_header, uint8_t *const dest, const size_t counter)
	Build the static part of the UDP header.
Variables
struct rohc_comp_profile	c_udp_profile
	Define the compression part of the UDP profile as described in the RFC 3095.

Detailed Description

ROHC compression context for the UDP profile.

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

Function Documentation

bool c_udp_check_context	(	const struct rohc_comp_ctxt *const	context,
		const struct net_pkt *const	packet
	)

Check if the IP/UDP packet belongs to the context.

Conditions are:

the number of IP headers must be the same as in context
IP version of the two IP headers must be the same as in context
IP packets must not be fragmented
the source and destination addresses of the two IP headers must match the ones in the context
the transport protocol must be UDP
the source and destination ports of the UDP header must match the ones in the context
IPv6 only: the Flow Label of the two IP headers must match the ones 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
	packet	The IP/UDP packet to check

Returns:: true if the IP/UDP packet belongs to the context false if it does not belong to the context

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

Check if the given packet corresponds to the UDP profile.

Conditions are:

the transport protocol is UDP
the version of the outer IP header is 4 or 6
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, the inner IP header is not an IP fragment
the inner IP payload is at least 8-byte long for UDP header
the UDP Length field and the UDP payload match

See also:: rohc_comp_rfc3095_check_profile

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

static bool c_udp_create	(	struct rohc_comp_ctxt *const	context,
		const struct net_pkt *const	packet
	)			`[static]`

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

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

Parameters:

	context	The compression context
	packet	The IP/UDP packet given to initialize the new context

Returns:: true if successful, false otherwise

static int c_udp_encode	(	struct rohc_comp_ctxt *const	context,
		const struct net_pkt *const	uncomp_pkt,
		uint8_t *const	rohc_pkt,
		const size_t	rohc_pkt_max_len,
		rohc_packet_t *const	packet_type,
		size_t *const	payload_offset
	)			`[static]`

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

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

static int udp_changed_udp_dynamic	(	const struct rohc_comp_ctxt *	context,
		const struct udphdr *	udp
	)			`[static]`

Check if the dynamic part of the UDP header changed.

Parameters:

	context	The compression context
	udp	The UDP header

Returns:: The number of UDP fields that changed

static size_t udp_code_dynamic_udp_part	(	const struct rohc_comp_ctxt *const	context,
		const uint8_t *const	next_header,
		uint8_t *const	dest,
		const size_t	counter
	)			`[static]`

Build the dynamic part of the UDP header.


 Dynamic part of UDP header (5.7.7.5):

    +---+---+---+---+---+---+---+---+
 1  /           Checksum            /   2 octets
    +---+---+---+---+---+---+---+---+

Parameters:

	context	The compression context
	next_header	The UDP header
	dest	The rohc-packet-under-build buffer
	counter	The current position in the rohc-packet-under-build buffer

Returns:: The new position in the rohc-packet-under-build buffer

size_t udp_code_static_udp_part	(	const struct rohc_comp_ctxt *const	context,
		const uint8_t *const	next_header,
		uint8_t *const	dest,
		const size_t	counter
	)

Build the static part of the UDP header.


 Static part of UDP header (5.7.7.5):

    +---+---+---+---+---+---+---+---+
 1  /          Source Port          /   2 octets
    +---+---+---+---+---+---+---+---+
 2  /       Destination Port        /   2 octets
    +---+---+---+---+---+---+---+---+

Parameters:

	context	The compression context
	next_header	The UDP header
	dest	The rohc-packet-under-build buffer
	counter	The current position in the rohc-packet-under-build buffer

Returns:: The new position in the rohc-packet-under-build buffer

size_t udp_code_uo_remainder	(	const struct rohc_comp_ctxt *const	context,
		const uint8_t *const	next_header,
		uint8_t *const	dest,
		const size_t	counter
	)

Build UDP-related fields in the tail of the UO packets.


     --- --- --- --- --- --- --- ---
    :                               :
 13 +         UDP Checksum          +  2 octets,
    :                               :  if context(UDP Checksum) != 0
     --- --- --- --- --- --- --- ---

Parameters:

	context	The compression context
	next_header	The UDP header
	dest	The rohc-packet-under-build buffer
	counter	The current position in the rohc-packet-under-build buffer

Returns:: The new position in the rohc-packet-under-build buffer

static void udp_decide_state ( struct rohc_comp_ctxt *const context ) [static]

Decide the state that should be used for the next packet compressed with the ROHC UDP profile.

The three states are:

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

Parameters:

context

The compression context

Variable Documentation

struct rohc_comp_profile c_udp_profile

Initial value:

{
        .id             = ROHC_PROFILE_UDP, 
        .protocol       = ROHC_IPPROTO_UDP, 
        .create         = c_udp_create,     
        .destroy        = rohc_comp_rfc3095_destroy,
        .check_profile  = c_udp_check_profile,
        .check_context  = c_udp_check_context,
        .encode         = c_udp_encode,
        .reinit_context = rohc_comp_reinit_context,
        .feedback       = rohc_comp_rfc3095_feedback,
}

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

c_udp.c File Reference

Data Structures

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation