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
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 rohc_pkt_hdrs *const uncomp_pkt_hdrs)
	Create a new UDP context and initialize it thanks to the given IP/UDP packet. More...
static rohc_packet_t	c_udp_decide_FO_packet (const struct rohc_comp_ctxt *const context)
	Decide which packet to send when in First Order (FO) state. More...
static rohc_packet_t	c_udp_decide_SO_packet (const struct rohc_comp_ctxt *const context)
	Decide which packet to send when in Second Order (SO) state. More...
static int	c_udp_encode (struct rohc_comp_ctxt *const context, const struct rohc_pkt_hdrs *const uncomp_pkt_hdrs, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len, rohc_packet_t *const packet_type)
	Encode an IP/UDP packet according to a pattern decided by several different factors. More...
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. More...
static void	udp_detect_udp_changes (const struct rohc_comp_ctxt *const context, const struct udphdr *const udp, struct udp_tmp_vars *const tmp)
	Detect changes in the UDP header. More...
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. More...
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. More...

Variables
const struct rohc_comp_profile	c_udp_profile
	Define the compression part of the UDP profile as described in the RFC 3095. More...

Detailed Description

ROHC compression context for the UDP profile.

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

Function Documentation

c_udp_create()

static bool c_udp_create ( struct rohc_comp_ctxt *const  context, const struct rohc_pkt_hdrs *const  uncomp_pkt_hdrs  )

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
uncomp_pkt_hdrs	The uncompressed headers to initialize the new context

Returns

true if successful, false otherwise

c_udp_decide_FO_packet()

static rohc_packet_t c_udp_decide_FO_packet ( const struct rohc_comp_ctxt *const  context )

static

Decide which packet to send when in First Order (FO) state.

Packets that can be used are the IR-DYN and UO-2 packets.

See also

decide_packet

Parameters

context

The compression context

Returns

The packet type among ROHC_PACKET_IR_DYN and ROHC_PACKET_UOR_2

c_udp_decide_SO_packet()

static rohc_packet_t c_udp_decide_SO_packet ( const struct rohc_comp_ctxt *const  context )

static

Decide which packet to send when in Second Order (SO) state.

Packets that can be used are the UO-0, UO-1 and UO-2 (with or without extensions) packets.

See also

decide_packet

Parameters

context

The compression context

Returns

The packet type among ROHC_PACKET_UO_0, ROHC_PACKET_UO_1 and ROHC_PACKET_UOR_2

c_udp_encode()

static int c_udp_encode ( struct rohc_comp_ctxt *const  context, const struct rohc_pkt_hdrs *const  uncomp_pkt_hdrs, uint8_t *const  rohc_pkt, const size_t  rohc_pkt_max_len, rohc_packet_t *const  packet_type  )

static

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

Parameters

context	The compression context
uncomp_pkt_hdrs	The uncompressed headers 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

Returns

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

udp_code_dynamic_udp_part()

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

udp_code_static_udp_part()

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

udp_code_uo_remainder()

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

udp_detect_udp_changes()

static void udp_detect_udp_changes ( const struct rohc_comp_ctxt *const  context, const struct udphdr *const  udp, struct udp_tmp_vars *const  tmp  )

static

Detect changes in the UDP header.

Parameters

	context	The compression context
	udp	The UDP header
[out]	tmp	The changes detected in the UDP header

Variable Documentation

c_udp_profile

const struct rohc_comp_profile c_udp_profile

Initial value:

=
{
        .id             = ROHC_PROFILE_UDP, 
        .create         = c_udp_create,     
        .destroy        = rohc_comp_rfc3095_destroy,
        .encode         = c_udp_encode,
        .feedback       = rohc_comp_rfc3095_feedback,
}

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