c_ip.c File Reference

ROHC compression context for the IP-only profile. More...

#include "c_ip.h"
#include "rohc_traces_internal.h"
#include "rohc_utils.h"
#include <string.h>
#include <assert.h>

Include dependency graph for c_ip.c:

Functions
static bool	rohc_ip_ctxt_create (struct rohc_comp_ctxt *const context, const struct net_pkt *const packet)
	Create a new context and initialize it thanks to the given IP packet. More...
bool	c_ip_check_context (const struct rohc_comp_ctxt *const context, const struct net_pkt *const packet)
	Check if an IP packet belongs to the context. More...
rohc_packet_t	c_ip_decide_FO_packet (const struct rohc_comp_ctxt *context)
	Decide which packet to send when in First Order (FO) state. More...
rohc_packet_t	c_ip_decide_SO_packet (const struct rohc_comp_ctxt *context)
	Decide which packet to send when in Second Order (SO) state. More...
uint32_t	c_ip_get_next_sn (const struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
	Determine the SN value for the next packet. More...
int	c_ip_code_ir_remainder (const struct rohc_comp_ctxt *const context, uint8_t *const dest, const size_t dest_max_len, const size_t counter)
	Code the remainder header for the IR or IR-DYN packets. More...

Variables
const struct rohc_comp_profile	c_ip_profile
	Define the compression part of the IP-only profile as described in the RFC 3843. More...

Detailed Description

ROHC compression context for the IP-only 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

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

Check if an IP 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
• IPv6 only: the Flow Label of the two IP headers must match the ones in the context
• the transport protocol must match the one in 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 packet to check

Returns

true if the IP packet belongs to the context false if it does not belong to the context

int c_ip_code_ir_remainder	(	const struct rohc_comp_ctxt *const	context,
		uint8_t *const	dest,
		const size_t	dest_max_len,
		const size_t	counter
	)

Code the remainder header for the IR or IR-DYN packets.

 Remainder of IR/IR-DYN packet (5.7.7.1):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 1  |             SN                |  2 octets if not RTP
    +---+---+---+---+---+---+---+---+

Parameters

context	The compression context
dest	The ROHC packet being coded
dest_max_len	The maximum length (in bytes) of the ROHC packet
counter	The current position in the ROHC buffer

Returns

The new position in ROHC buffer in case of success, -1 in case of failure

rohc_packet_t c_ip_decide_FO_packet

(

const struct rohc_comp_ctxt *

context

)

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

rohc_packet_t c_ip_decide_SO_packet

(

const struct rohc_comp_ctxt *

context

)

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

uint32_t c_ip_get_next_sn	(	const struct rohc_comp_ctxt *const	context,
		const struct net_pkt *const	uncomp_pkt
	)

Determine the SN value for the next packet.

Profile SN is an internal increasing 16-bit number.

Parameters

context	The compression context
uncomp_pkt	The uncompressed packet to encode

Returns

The SN

static bool rohc_ip_ctxt_create ( struct rohc_comp_ctxt *const  context, const struct net_pkt *const  packet  )

static

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

Returns

true if successful, false otherwise

Variable Documentation

const struct rohc_comp_profile c_ip_profile

Initial value:

=
{
        .id             = ROHC_PROFILE_IP,     
        .protocol       = 0,                   
        .create         = rohc_ip_ctxt_create, 
        .destroy        = rohc_comp_rfc3095_destroy,
        .check_profile  = rohc_comp_rfc3095_check_profile,
        .check_context  = c_ip_check_context,
        .encode         = rohc_comp_rfc3095_encode,
        .reinit_context = rohc_comp_reinit_context,
        .feedback       = rohc_comp_rfc3095_feedback,
}

Define the compression part of the IP-only profile as described in the RFC 3843.