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

#include "c_generic.h"
#include "c_rtp.h"
#include "config.h"
#include "rohc_traces.h"
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <math.h>
#include <assert.h>

Include dependency graph for c_generic.c:

Functions
int	code_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest)
	Build the ROHC packet to send.
int	code_IR_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest)
	Build the IR packet.
int	code_IR_DYN_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest)
	Build the IR-DYN packet.
int	code_generic_static_part (struct c_context context, struct ip_header_info header_info, const struct ip_packet ip, unsigned char *dest, int counter)
	Build the static part of the IR and IR-DYN packets.
int	code_ipv4_static_part (struct c_context context, struct ip_header_info header_info, const struct ip_packet ip, unsigned char *dest, int counter)
	Build the IPv4 static part of the IR and IR-DYN packets.
int	code_ipv6_static_part (struct c_context context, struct ip_header_info header_info, struct ip_packet ip, unsigned char *dest, int counter)
	Build the IPv6 static part of the IR and IR-DYN packets.
int	code_generic_dynamic_part (struct c_context context, struct ip_header_info header_info, const struct ip_packet ip, unsigned char *dest, int counter)
	Build the dynamic part of the IR and IR-DYN packets.
int	code_ipv4_dynamic_part (struct c_context context, struct ip_header_info header_info, const struct ip_packet ip, unsigned char *dest, int counter)
	Build the IPv4 dynamic part of the IR and IR-DYN packets.
int	code_ipv6_dynamic_part (struct c_context context, struct ip_header_info header_info, const struct ip_packet ip, unsigned char *dest, int counter)
	Build the IPv6 dynamic part of the IR and IR-DYN packets.
int	code_UO_packet_tail (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest, int counter)
	Build the tail of the UO packet.
int	code_UO0_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest)
	Build the UO-0 packet.
int	code_UO1_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest)
	Build the UO-1 packet.
int	code_UO2_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, const unsigned char next_header, unsigned char *dest)
	Build the UO-2 packet.
int	code_UOR2_bytes (struct c_context context, int extension, unsigned char f_byte, unsigned char s_byte, unsigned char t_byte)
	Code some fields of the UOR-2 packet.
int	code_UOR2_RTP_bytes (struct c_context context, int extension, unsigned char f_byte, unsigned char s_byte, unsigned char t_byte)
	Code some fields of the UOR-2-RTP packet.
int	code_UOR2_TS_bytes (struct c_context context, int extension, unsigned char f_byte, unsigned char s_byte, unsigned char t_byte)
	Code some fields of the UOR-2-TS packet.
int	code_UOR2_ID_bytes (struct c_context context, int extension, unsigned char f_byte, unsigned char s_byte, unsigned char t_byte)
	Code some fields of the UOR-2-ID packet.
int	code_EXT0_packet (struct c_context context, unsigned char dest, int counter)
	Build the extension 0 of the UO-2 packet.
int	code_EXT1_packet (struct c_context context, unsigned char dest, int counter)
	Build the extension 1 of the UO-2 packet.
int	code_EXT2_packet (struct c_context context, unsigned char dest, int counter)
	Build the extension 2 of the UO-2 packet.
int	code_EXT3_packet (struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, unsigned char dest, int counter)
	Build the extension 3 of the UO-2 packet.
void	create_ipv6_item (unsigned char ext, int index_table, int size, struct list_comp comp)
	Update an IPv6 item with the extension.
unsigned char *	get_ipv6_extension (const struct ip_packet ip, int index)
	Extract the Nth IP extension of the IP packet.
int	ipv6_compare (unsigned char ext, struct list_comp comp, int size, int index_table)
	Ipv6 extension comparison.
int	get_index_ipv6_table (const struct ip_packet ip, int index)
	Return the based table index for the Nth IP extension of the IP packet.
int	get_ipv6_ext_size (unsigned char *ext)
	Get the size of the IPv6 extension.
void	decide_state (struct c_context *context)
	Decide the state that should be used for the next packet.
int	decide_packet (struct c_context *context, const struct ip_packet ip, const struct ip_packet ip2, int size_data)
	Decide which packet to send when in the different states.
void	update_variables (struct c_context *context, const struct ip_packet ip, const struct ip_packet ip2)
	Update some context variables.
int	decide_extension (struct c_context *context)
	Decide what extension shall be used in the UO-2 packet.
int	rtp_header_flags_and_fields (struct c_context context, unsigned short changed_f, const struct ip_packet ip, unsigned char dest, int counter)
int	header_flags (struct c_context context, struct ip_header_info header_info, unsigned short changed_f, const struct ip_packet ip, boolean is_outer, int nr_ip_id_bits, unsigned char *dest, int counter)
	Build inner or outer IP header flags.
int	header_fields (struct c_context context, struct ip_header_info header_info, unsigned short changed_f, const struct ip_packet ip, boolean is_outer, int nr_ip_id_bits, unsigned char *dest, int counter)
	Build inner or outer IP header fields.
int	changed_static_both_hdr (struct c_context *context, const struct ip_packet ip, const struct ip_packet ip2)
	Check if the static parts of the context changed in any of the two IP headers.
int	changed_static_one_hdr (unsigned short changed_fields, struct ip_header_info header_info, const struct ip_packet ip, struct c_context context)
	Check if the static part of the context changed in the new IP packet.
int	changed_dynamic_both_hdr (struct c_context *context, const struct ip_packet ip, const struct ip_packet ip2)
	Check if the dynamic parts of the context changed in any of the two IP headers.
int	changed_dynamic_one_hdr (unsigned short changed_fields, struct ip_header_info header_info, const struct ip_packet ip, struct c_context context)
	Check if the dynamic part of the context changed in the IP packet.
unsigned short	changed_fields (struct ip_header_info *header_info, const struct ip_packet ip)
	Find the IP fields that changed between the profile and a new IP packet.
void	check_ip_identification (struct ip_header_info *header_info, const struct ip_packet ip)
	Determine whether the IPv4 Identification field of one IPv4 header is random and/or in Network Bit Order (NBO).
int	c_assessment_size (struct rohc_comp comp, struct c_context context, const struct ip_packet ip, int packet, int size_data, int original)
	Make an assessment of the size in byte of the paquet which will be sent.
int	decide_algo (struct rohc_comp comp, struct c_context context, const struct ip_packet ip, const struct ip_packet ip2, int packet, int size_data)
boolean	is_changed (unsigned short changed_fields, unsigned short check_field)
	Check if a specified IP field has changed.
void	ip6_c_init_table (struct list_comp *comp)
	Initialize the tables IPv6 extension in compressor.
int	c_init_header_info (struct ip_header_info *header_info, const struct ip_packet ip)
	Initialize the inner or outer IP header info stored in the context.
void	c_init_tmp_variables (struct generic_tmp_variables *tmp_variables)
	Initialize all temporary variables stored in the context.
int	c_generic_create (struct c_context *context, const struct ip_packet ip)
	Create a new context and initialize it thanks to the given IP packet.
void	c_generic_destroy (struct c_context *context)
	Destroy the context.
void	change_mode (struct c_context *context, rohc_mode new_mode)
	Change the mode of the context.
void	change_state (struct c_context *context, rohc_c_state new_state)
	Change the state of the context.
int	c_generic_encode (struct c_context context, const struct ip_packet ip, int packet_size, unsigned char dest, int dest_size, int *payload_offset)
	Encode an IP packet according to a pattern decided by several different factors.
int	c_algo_list_compress (struct list_comp *comp, const struct ip_packet ip)
	Algorithm of compression list.
int	c_create_current_list (int index, struct list_comp comp, unsigned char ext, int index_table)
	Create the current list.
int	decide_type (struct list_comp *comp)
	Decide the encoding type for compression list.
int	encode_list (struct list_comp comp, unsigned char dest, int counter, int ps, int size)
	Generique encoding of compressed list.
int	encode_type_0 (struct list_comp comp, unsigned char dest, int counter, int ps)
	build Encoding type 0
int	encode_type_1 (struct list_comp comp, unsigned char dest, int counter, int ps)
	build Encoding type 1
int	encode_type_2 (struct list_comp comp, unsigned char dest, int counter, int ps)
	build Encoding type 2
int	encode_type_3 (struct list_comp comp, unsigned char dest, int counter, int ps)
	build Encoding type 3
void	c_generic_feedback (struct c_context context, struct c_feedback feedback)
	Update the profile when feedback arrives.
void	periodic_down_transition (struct c_context *context)
	Periodically change the context state after a certain number of packets.
int	decide_FO_packet (struct c_context *context)
	Decide which packet to send when in First Order (FO) state.
int	decide_SO_packet (const struct c_context *context)
	Decide which packet to send when in Second Order (SO) state.
Variables
const char *	generic_packet_types []
	The description of the different ROHC packets.
const char *	generic_extension_types []
	The description of the different extensions for the UO-2 packet.

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>; David Moreau from TAS; Emmanuelle Pechereau <epechereau@toulouse.viveris.com>; The hackers from ROHC for Linux

Function Documentation

int c_algo_list_compress	(	struct list_comp *	comp,
		const struct ip_packet	ip
	)

Algorithm of compression list.

This function compress a generic extension list

Parameters:

comp	The list compressor which is specific to the extension type
ip	The ip packet to compress

Returns:: 1 if a compressed list must be sent, 0 if not and -1 if error

References c_create_current_list(), c_translation::counter, list_comp::counter, list_comp::curr_list, ip_packet::data, delete_elt(), empty_list(), c_list::gen_id, get_elt(), list_comp::get_extension, list_comp::get_index_table, list_elt::index_table, insert_elt(), list_comp::islist, list_elt::item, c_translation::known, L, MAX_ITEM, list_comp::ref_list, rohc_debugf, size_list(), list_comp::trans_table, item::type, and list_comp::update_done.

Referenced by code_ipv6_dynamic_part(), and decide_packet().

int c_assessment_size	(	struct rohc_comp *	comp,
		struct c_context *	context,
		const struct ip_packet	ip,
		int	packet,
		int	size_data,
		int	original
	)

Make an assessment of the size in byte of the paquet which will be sent.

Parameters:

comp	The rohc compressor
context	The context used for the compression
ip	The packet which will be compressed
packet	The type of the packet which will be compressed
size_data	The size of the data in bytes
original	Indicate if the specified packet is the original ROHC packet

Returns:: the size assessment of the ROHC packet

References medium::cid_type, c_profile::id, ip_get_protocol(), ip_get_version(), IPV4, rohc_comp::medium, PACKET_IR, PACKET_IR_DYN, PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, rohc_debugf, ROHC_PROFILE_IP, ROHC_PROFILE_RTP, ROHC_PROFILE_UDP, and ROHC_PROFILE_UDPLITE.

Referenced by decide_algo().

int c_create_current_list	(	int	index,
		struct list_comp *	comp,
		unsigned char *	ext,
		int	index_table
	)

Create the current list.

Parameters:

index	the number of the extension
comp	The list compressor which is specific to the extension type
ext	The extension
index_table	The index of the item in the based table

Returns:: 1 if successfull, 0 else

References list_comp::based_table, list_comp::compare, c_translation::counter, list_comp::counter, list_comp::create_item, list_comp::curr_list, delete_elt(), elt_index(), get_elt(), list_comp::get_size, list_elt::index_table, insert_elt(), list_elt::item, c_translation::known, item::length, push_back(), rohc_debugf, list_comp::trans_table, and item::type.

Referenced by c_algo_list_compress().

int c_generic_create	(	struct c_context *	context,
		const struct ip_packet	ip
	)

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
ip	The IP packet given to initialize the new context

Returns:: 1 if successful, 0 otherwise

Referenced by c_rtp_create(), c_udp_create(), and c_udp_lite_create().

void c_generic_destroy ( struct c_context * 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

References c_destroy_wlsb(), list_comp::curr_list, destroy_list(), ipv6_header_info::ext_comp, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, ipv4_header_info::ip_id_window, IPV4, IPV6, c_generic_context::is_ip2_initialized, list_comp::ref_list, c_generic_context::sn_window, c_context::specific, c_generic_context::specific, ip_header_info::v4, ip_header_info::v6, ip_header_info::version, and zfree.

Referenced by c_generic_create(), c_rtp_create(), c_rtp_destroy(), c_udp_create(), and c_udp_lite_create().

int c_generic_encode	(	struct c_context *	context,
		const struct ip_packet	ip,
		int	packet_size,
		unsigned char *	dest,
		int	dest_size,
		int *	payload_offset
	)

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

1. Check if we have double IP headers.
2. Check if the IP-ID fields are random and if they are in NBO.
3. Decide in which state to go (IR, FO or SO).
4. Decide how many bits are needed to send the IP-ID and SN fields and more important update the sliding windows.
5. Decide which packet type to send.
6. Code the packet.

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

Parameters:

context	The compression context
ip	The IP packet to encode
packet_size	The length of the IP packet to encode
dest	The rohc-packet-under-build buffer
dest_size	The length of the rohc-packet-under-build buffer
payload_offset	The offset for the payload in the IP packet

Returns:: The length of the created ROHC packet or -1 in case of failure

Referenced by c_rtp_encode(), c_udp_encode(), and c_udp_lite_encode().

void c_generic_feedback	(	struct c_context *	context,
		struct c_feedback *	feedback
	)

Update the profile when feedback arrives.

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 including the whole feedback packet

References c_feedback::acktype, c_ack_sn_wlsb(), change_mode(), change_state(), crc_calculate(), CRC_INIT_8, CRC_TYPE_8, c_feedback::data, FO, ip_header_info::info, c_generic_context::ip_flags, ipv4_header_info::ip_id_window, IPV4, IR, c_generic_context::ir_dyn_count, rohc_debugf, c_feedback::size, sn, c_generic_context::sn_window, SO, c_context::specific, c_feedback::specific_offset, c_feedback::specific_size, c_context::state, c_feedback::type, ip_header_info::v4, and ip_header_info::version.

int c_init_header_info	(	struct ip_header_info *	header_info,
		const struct ip_packet	ip
	)

Initialize the inner or outer IP header info stored in the context.

Parameters:

header_info	The inner or outer IP header info to initialize
ip	The inner or outer IP header

Returns:: 1 if successful, 0 otherwise

Referenced by c_generic_create(), and c_generic_encode().

void c_init_tmp_variables ( struct generic_tmp_variables * tmp_variables )

Initialize all temporary variables stored in the context.

Parameters:

tmp_variables The temporary variables to initialize

References generic_tmp_variables::changed_fields, generic_tmp_variables::changed_fields2, generic_tmp_variables::max_size, generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_ip_id_bits2, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::nr_sn_bits, generic_tmp_variables::packet_type, generic_tmp_variables::send_dynamic, and generic_tmp_variables::send_static.

Referenced by c_generic_create().

void change_mode	(	struct c_context *	context,
		rohc_mode	new_mode
	)

Change the mode of the context.

Parameters:

context	The compression context
new_mode	The new mode the context must enter in

References change_state(), IR, c_context::mode, and rohc_debugf.

Referenced by c_generic_feedback().

void change_state	(	struct c_context *	context,
		rohc_c_state	new_state
	)

Change the state of the context.

Parameters:

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

References c_generic_context::fo_count, c_generic_context::ir_count, rohc_debugf, c_generic_context::so_count, c_context::specific, and c_context::state.

Referenced by c_generic_feedback(), change_mode(), decide_state(), periodic_down_transition(), rtp_decide_state(), and udp_decide_state().

int changed_dynamic_both_hdr	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2
	)

Check if the dynamic parts of the context changed in any of the two IP headers.

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header

Returns:: The number of fields that changed

References changed_dynamic_one_hdr(), generic_tmp_variables::changed_fields, changed_fields(), generic_tmp_variables::changed_fields2, c_generic_context::ip2_flags, c_generic_context::ip_flags, generic_tmp_variables::nr_of_ip_hdr, rohc_debugf, c_context::specific, and c_generic_context::tmp_variables.

Referenced by c_generic_encode().

int changed_dynamic_one_hdr	(	unsigned short	changed_fields,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		struct c_context *	context
	)

Check if the dynamic part of the context changed in the IP packet.

The fields classified as CHANGING by RFC need to be checked for change. The fields are:

the TOS, IP-ID and TTL fields for IPv4,
the TC and HL fields for IPv6.

The IP-ID changes are managed outside of this function.

Althought classified as STATIC, the IPv4 Don't Fragment flag is not part of the static initialization, but of the dynamic initialization. It needs to be checked for change.

Other flags are checked for change for IPv4. There are IP-ID related flags:

RND: is the IP-ID random ?
NBO: is the IP-ID in Network Byte Order ?

Parameters:

changed_fields	The fields that changed, created by the function changed_fields
header_info	The header info stored in the profile
ip	The header of the new IP packet
context	The compression context

Returns:: The number of fields that changed

References ipv4_header_info::df_count, c_generic_context::fo_count, ip_header_info::info, ip_get_version(), IPV4, IPV4_GET_DF, ipv4_get_df(), is_changed(), MAX_FO_COUNT, MOD_TOS, MOD_TTL, ipv4_header_info::nbo, ipv4_header_info::nbo_count, ipv4_header_info::old_ip, ipv4_header_info::old_nbo, ipv4_header_info::old_rnd, ipv4_header_info::rnd, ipv4_header_info::rnd_count, rohc_debugf, c_context::specific, ip_header_info::tos_count, ip_header_info::ttl_count, and ip_header_info::v4.

Referenced by changed_dynamic_both_hdr(), and code_EXT3_packet().

unsigned short changed_fields	(	struct ip_header_info *	header_info,
		const struct ip_packet	ip
	)

Find the IP fields that changed between the profile and a new IP packet.

Only some fields are checked for change in the compression process, so only check these ones to avoid useless work. The fields to check are: TOS/TC, TTL/HL and Protocol/Next Header.

Parameters:

header_info	The header info stored in the profile
ip	The header of the new IP packet

Returns:: The bitpattern that indicates which field changed

References ip_header_info::info, ip_get_protocol(), ip_get_tos(), ip_get_ttl(), ip_get_version(), IPV4, IPV6_GET_TC, MOD_PROTOCOL, MOD_TOS, MOD_TTL, ipv4_header_info::old_ip, ipv6_header_info::old_ip, ip_header_info::v4, and ip_header_info::v6.

Referenced by c_generic_encode(), changed_dynamic_both_hdr(), and changed_static_both_hdr().

int changed_static_both_hdr	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2
	)

Check if the static parts of the context changed in any of the two IP headers.

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header

Returns:: The number of fields that changed

References generic_tmp_variables::changed_fields, changed_fields(), generic_tmp_variables::changed_fields2, changed_static_one_hdr(), c_generic_context::ip2_flags, c_generic_context::ip_flags, generic_tmp_variables::nr_of_ip_hdr, c_context::specific, and c_generic_context::tmp_variables.

Referenced by c_generic_encode().

int changed_static_one_hdr	(	unsigned short	changed_fields,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		struct c_context *	context
	)

Check if the static part of the context changed in the new IP packet.

The fields classified as STATIC-DEF by RFC do not need to be checked for change. These fields are constant for all packets in a stream (ie. a profile context). So, the Source Address and Destination Address fields are not checked for change for both IPv4 and IPv6. The Flow Label is not checked for IPv6.

Althought not classified as STATIC-DEF, the Version field is the same for all packets in a stream (ie. a profile context) and therefore does not need to be checked for change neither for IPv4 nor IPv6.

Althought classified as STATIC, the IPv4 Don't Fragment flag is not part of the static initialization, but of the dynamic initialization.

Summary:

For IPv4, check the Protocol field for change.
For IPv6, check the Next Header field for change.

Parameters:

changed_fields	The fields that changed, created by the function changed_fields
header_info	The header info stored in the profile
ip	The header of the new IP packet
context	The compression context

Returns:: The number of fields that changed

References c_generic_context::fo_count, is_changed(), MAX_FO_COUNT, MOD_PROTOCOL, ip_header_info::protocol_count, rohc_debugf, and c_context::specific.

Referenced by changed_static_both_hdr(), and code_EXT3_packet().

void check_ip_identification	(	struct ip_header_info *	header_info,
		const struct ip_packet	ip
	)

Determine whether the IPv4 Identification field of one IPv4 header is random and/or in Network Bit Order (NBO).

Parameters:

header_info	The header info stored in the profile
ip	One IPv4 header

References ip_header_info::info, ip_get_version(), IPID_MAX_DELTA, IPV4, ipv4_get_id(), ipv4_header_info::nbo, ipv4_header_info::old_ip, ipv4_header_info::rnd, rohc_debugf, and ip_header_info::v4.

Referenced by c_generic_encode().

int code_EXT0_packet	(	struct c_context *	context,
		unsigned char *	dest,
		int	counter
	)

Build the extension 0 of the UO-2 packet.


 Extension 0 for non-RTP profiles (5.11.4):

    +---+---+---+---+---+---+---+---+
 1  | 0   0 |    SN     |   IP-ID   |
    +---+---+---+---+---+---+---+---+

 Extension 0 for RTP profile (5.7.5):

    +---+---+---+---+---+---+---+---+
 1  | 0   0 |    SN     |    +T     |
    +---+---+---+---+---+---+---+---+

 if T = 0 -> +T = IP-ID
          -> -T = TS

 if T = 1 -> +T = TS
          -> -T = IP-ID

 no T bit -> +T = -T = TS

Parameters:

context	The compression context
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 if successful, -1 otherwise

References ipv4_header_info::id_delta, ip_header_info::info, c_generic_context::ip_flags, IPV4, generic_tmp_variables::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, rohc_debugf, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, rtp_tmp_variables::ts_send, ip_header_info::v4, and ip_header_info::version.

Referenced by code_UO2_packet().

int code_EXT1_packet	(	struct c_context *	context,
		unsigned char *	dest,
		int	counter
	)

Build the extension 1 of the UO-2 packet.


 Extension 1 for non-RTP profiles (5.11.4):

    +---+---+---+---+---+---+---+---+
 1  | 0   1 |    SN     |   IP-ID   |
    +---+---+---+---+---+---+---+---+
 2  |             IP-ID             |
    +---+---+---+---+---+---+---+---+

 Extension 1 for RTP profile (5.7.5):

    +---+---+---+---+---+---+---+---+
 1  | 0   1 |    SN     |    +T     |
    +---+---+---+---+---+---+---+---+
 2  |               -T              |
    +---+---+---+---+---+---+---+---+

 if T = 0 -> +T = IP-ID
          -> -T = TS

 if T = 1 -> +T = TS
          -> -T = IP-ID

 no T bit -> +T = -T = TS

Parameters:

context	The compression context
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 if successful, -1 otherwise

References ipv4_header_info::id_delta, ip_header_info::info, c_generic_context::ip_flags, IPV4, generic_tmp_variables::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, rohc_debugf, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, rtp_tmp_variables::ts_send, ip_header_info::v4, and ip_header_info::version.

Referenced by code_UO2_packet().

int code_EXT2_packet	(	struct c_context *	context,
		unsigned char *	dest,
		int	counter
	)

Build the extension 2 of the UO-2 packet.


 Extension 2 for non-RTP profiles (5.11.4):

    +---+---+---+---+---+---+---+---+
 1  | 1   0 |    SN     |   IP-ID2  |
    +---+---+---+---+---+---+---+---+
 2  |            IP-ID2             |
    +---+---+---+---+---+---+---+---+
 3  |             IP-ID             |
    +---+---+---+---+---+---+---+---+

 IP-ID2 is for outer IP-ID field

 Extension 2 for RTP profile (5.7.5):

    +---+---+---+---+---+---+---+---+
 1  | 1   0 |    SN     |     +T    |
    +---+---+---+---+---+---+---+---+
 2  |               +T              |
    +---+---+---+---+---+---+---+---+
 3  |               -T              |
    +---+---+---+---+---+---+---+---+

 if T = 0 -> +T = IP-ID
          -> -T = TS

 if T = 1 -> +T = TS
          -> -T = IP-ID

 no T bit -> +T = -T = TS

Parameters:

context	The compression context
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 if successful, -1 otherwise

References ipv4_header_info::id_delta, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, IPV4, generic_tmp_variables::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, rohc_debugf, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, rtp_tmp_variables::ts_send, ip_header_info::v4, and ip_header_info::version.

Referenced by code_UO2_packet().

int code_EXT3_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		unsigned char *	dest,
		int	counter
	)

Build the extension 3 of the UO-2 packet.


 Extension 3 for non-RTP profiles (5.7.5 & 5.11.4):
 
       0     1     2     3     4     5     6     7
    +-----+-----+-----+-----+-----+-----+-----+-----+
 1  |  1     1  |  S  |   Mode    |  I  | ip  | ip2 |
    +-----+-----+-----+-----+-----+-----+-----+-----+
 2  |            Inner IP header flags        |     |  if ip = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
 3  |            Outer IP header flags              |
    +-----+-----+-----+-----+-----+-----+-----+-----+
 4  |                      SN                       |  if S = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 5  /            Inner IP header fields             /  variable,
    |                                               |
    +-----+-----+-----+-----+-----+-----+-----+-----+
 6  |                     IP-ID                     |  2 octets, if I = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 7  /            Outer IP header fields             /  variable,
    |                                               |
    +-----+-----+-----+-----+-----+-----+-----+-----+

 Extension 3 for RTP profile (5.7.5):

       0     1     2     3     4     5     6     7
    +-----+-----+-----+-----+-----+-----+-----+-----+
 1  |  1     1  |  S  |R-TS | Tsc |  I  | ip  | rtp |
    +-----+-----+-----+-----+-----+-----+-----+-----+
 2  |            Inner IP header flags        | ip2 |  if ip = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
 3  |            Outer IP header flags              |
    +-----+-----+-----+-----+-----+-----+-----+-----+
 4  |                      SN                       |  if S = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
4.1 /                      TS                       / 1-4octets, if R-TS = 1
    |                                               |
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 5  /            Inner IP header fields             /  variable,
    |                                               |  if ip = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
 6  |                     IP-ID                     |  2 octets, if I = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 7  /            Outer IP header fields             /  variable,
    |                                               |  if ip2 = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |  variable,
 8  /          RTP Header flags and fields          /  if rtp = 1
    |                                               |
    +-----+-----+-----+-----+-----+-----+-----+-----+

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP 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 if successful, -1 otherwise

References c_bytesSdvl(), c_encodeSdvl(), changed_dynamic_one_hdr(), generic_tmp_variables::changed_fields, generic_tmp_variables::changed_fields2, changed_static_one_hdr(), header_fields(), header_flags(), c_profile::id, ip_header_info::info, INIT_STRIDE, c_generic_context::ip2_flags, c_generic_context::ip_flags, ip_get_version(), IPV4, ipv4_get_id_nbo(), is_deductible(), is_ts_constant(), MAX_FO_COUNT, c_context::mode, ipv4_header_info::nbo, generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_ip_id_bits2, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, rtp_tmp_variables::nr_ts_bits_ext3, generic_tmp_variables::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, ipv4_header_info::rnd, ipv4_header_info::rnd_count, rohc_debugf, ROHC_PROFILE_RTP, rtp_header_flags_and_fields(), sc_rtp_context::rtp_pt_change_count, rtp_tmp_variables::rtp_pt_changed, SEND_SCALED, c_generic_context::sn, c_context::specific, c_generic_context::specific, ts_sc_comp::state, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, sc_rtp_context::ts_sc, rtp_tmp_variables::ts_send, and ip_header_info::v4.

Referenced by code_UO2_packet().

int code_generic_dynamic_part	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

Build the dynamic part of the IR and IR-DYN packets.

Parameters:

context	The compression context
header_info	The IP header info stored in the profile
ip	The IP header the dynamic part is built for
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

References code_ipv4_dynamic_part(), code_ipv6_dynamic_part(), ip_get_version(), and IPV4.

Referenced by code_IR_DYN_packet(), and code_IR_packet().

int code_generic_static_part	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

Build the static part of the IR and IR-DYN packets.

Parameters:

context	The compression context
header_info	The IP header info stored in the profile
ip	The IP header the static part is built for
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

References code_ipv4_static_part(), code_ipv6_static_part(), ip_get_version(), and IPV4.

Referenced by code_IR_packet().

int code_ipv4_dynamic_part	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

Build the IPv4 dynamic part of the IR and IR-DYN packets.


 Dynamic part IPv4 (5.7.7.4):
 
    +---+---+---+---+---+---+---+---+
 1  |        Type of Service        |
   +---+---+---+---+---+---+---+---+
 2  |         Time to Live          |
    +---+---+---+---+---+---+---+---+
 3  /        Identification         /   2 octets
    +---+---+---+---+---+---+---+---+
 4  | DF|RND|NBO|         0         |
    +---+---+---+---+---+---+---+---+
 5  / Generic extension header list /  variable length
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
header_info	The IP header info stored in the profile
ip	The IPv4 header the dynamic part is built for
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

References ipv4_header_info::df_count, ip_header_info::info, ip_get_tos(), ip_get_ttl(), ipv4_get_df(), ipv4_get_id_nbo(), ipv4_header_info::nbo, ipv4_header_info::nbo_count, ipv4_header_info::rnd, ipv4_header_info::rnd_count, rohc_debugf, ip_header_info::tos_count, ip_header_info::ttl_count, and ip_header_info::v4.

Referenced by code_generic_dynamic_part().

int code_ipv4_static_part	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

Build the IPv4 static part of the IR and IR-DYN packets.


 Static part IPv4 (5.7.7.4):

    +---+---+---+---+---+---+---+---+
 1  |  Version = 4  |       0       |
    +---+---+---+---+---+---+---+---+
 2  |           Protocol            |
    +---+---+---+---+---+---+---+---+
 3  /        Source Address         /   4 octets
    +---+---+---+---+---+---+---+---+
 4  /      Destination Address      /   4 octets
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
header_info	The IP header info stored in the profile
ip	The IPv4 header the static part is built for
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

References ip_get_protocol(), ipv4_get_daddr(), ipv4_get_saddr(), ip_header_info::protocol_count, and rohc_debugf.

Referenced by code_generic_static_part().

int code_ipv6_dynamic_part	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		const struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

Build the IPv6 dynamic part of the IR and IR-DYN packets.


 Dynamic part IPv6 (5.7.7.3):

    +---+---+---+---+---+---+---+---+
 1  |         Traffic Class         |   1 octet
    +---+---+---+---+---+---+---+---+
 2  |           Hop Limit           |   1 octet
    +---+---+---+---+---+---+---+---+
 3  / Generic extension header list /   variable length
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
header_info	The IP header info stored in the profile
ip	The IPv6 header the dynamic part is built for
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

References c_algo_list_compress(), list_comp::curr_list, encode_list(), ipv6_header_info::ext_comp, ip_header_info::info, ip_get_tos(), ip_get_ttl(), list_comp::islist, list_comp::list_compress, list_comp::ref_list, rohc_debugf, size_list(), ip_header_info::tos_count, ip_header_info::ttl_count, list_comp::update_done, and ip_header_info::v6.

Referenced by code_generic_dynamic_part().

int code_ipv6_static_part	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

Build the IPv6 static part of the IR and IR-DYN packets.


 Static part IPv6 (5.7.7.3):

    +---+---+---+---+---+---+---+---+
 1  |  Version = 6  |Flow Label(msb)|   1 octet
    +---+---+---+---+---+---+---+---+
 2  /        Flow Label (lsb)       /   2 octets
    +---+---+---+---+---+---+---+---+
 3  |          Next Header          |   1 octet
    +---+---+---+---+---+---+---+---+
 4  /        Source Address         /   16 octets
    +---+---+---+---+---+---+---+---+
 5  /      Destination Address      /   16 octets
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
header_info	The IP header info stored in the profile
ip	The IPv6 header the static part is built for
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

References ip_get_protocol(), IPV6_ADDR, IPV6_ADDR_FORMAT, ipv6_get_daddr(), ipv6_get_flow_label(), ipv6_get_saddr(), ip_header_info::protocol_count, and rohc_debugf.

Referenced by code_generic_static_part().

int code_IR_DYN_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest
	)

Build the IR-DYN packet.


 IR-DYN packet (5.7.7.2):

      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  :         Add-CID octet         : if for small CIDs and CID != 0
    +---+---+---+---+---+---+---+---+
 2  | 1   1   1   1   1   0   0   0 | IR-DYN packet type
    +---+---+---+---+---+---+---+---+
    :                               :
 3  /     0-2 octets of CID info    / 1-2 octets if for large CIDs
    :                               :
    +---+---+---+---+---+---+---+---+
 4  |            Profile            | 1 octet
    +---+---+---+---+---+---+---+---+
 5  |              CRC              | 1 octet
    +---+---+---+---+---+---+---+---+
    |                               |
 6  /         Dynamic chain         / variable length
    |                               |
    +---+---+---+---+---+---+---+---+
 7  |             SN                | 2 octets if not RTP
    +---+---+---+---+---+---+---+---+
    :                               :
    /           Payload             / variable length
    :                               :
     - - - - - - - - - - - - - - - -

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header data used to code the dynamic part of the next header for some profiles such as UDP, UDP-Lite, etc.
dest	The rohc-packet-under-build buffer

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

References c_context::cid, code_cid_values(), c_generic_context::code_dynamic_part, code_generic_dynamic_part(), crc_calculate(), CRC_INIT_8, CRC_TYPE_8, c_profile::id, c_generic_context::init_at_IR, c_generic_context::ip2_flags, c_generic_context::ip_flags, generic_tmp_variables::max_size, generic_tmp_variables::nr_of_ip_hdr, c_context::profile, rohc_debugf, ROHC_PROFILE_RTP, c_generic_context::sn, c_context::specific, and c_generic_context::tmp_variables.

Referenced by code_packet().

int code_IR_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest
	)

Build the IR packet.


 IR packet (5.7.7.1):

      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  |         Add-CID octet         |  if for small CIDs and CID != 0
    +---+---+---+---+---+---+---+---+
 2  | 1   1   1   1   1   1   0 | D |
    +---+---+---+---+---+---+---+---+
    |                               |
 3  /    0-2 octets of CID info     /  1-2 octets if for large CIDs
    |                               |
    +---+---+---+---+---+---+---+---+
 4  |            Profile            |  1 octet
    +---+---+---+---+---+---+---+---+
 5  |              CRC              |  1 octet
    +---+---+---+---+---+---+---+---+
    |                               |
 6  |         Static chain          |  variable length
    |                               |
    +---+---+---+---+---+---+---+---+
    |                               |
 7  |         Dynamic chain         |  present if D = 1, variable length
    |                               |
    +---+---+---+---+---+---+---+---+
 8  |             SN                |  2 octets if not RTP
    +---+---+---+---+---+---+---+---+
    |                               |
    |           Payload             |  variable length
    |                               |
     - - - - - - - - - - - - - - - -

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header data used to code the static and dynamic parts of the next header for some profiles such as UDP, UDP-Lite, and so on.
dest	The rohc-packet-under-build buffer

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

References c_context::cid, code_cid_values(), c_generic_context::code_dynamic_part, code_generic_dynamic_part(), code_generic_static_part(), c_generic_context::code_static_part, crc_calculate(), CRC_INIT_8, CRC_TYPE_8, c_profile::id, c_generic_context::init_at_IR, c_generic_context::ip2_flags, c_generic_context::ip_flags, generic_tmp_variables::max_size, generic_tmp_variables::nr_of_ip_hdr, c_context::profile, rohc_debugf, ROHC_PROFILE_RTP, sn, c_generic_context::sn, c_context::specific, and c_generic_context::tmp_variables.

Referenced by code_packet().

int code_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest
	)

Build the ROHC packet to send.

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header such as UDP or UDP-Lite
dest	The rohc-packet-under-build buffer

Returns:: The position in the rohc-packet-under-build buffer if successful, -1 otherwise

References code_IR_DYN_packet(), code_IR_packet(), code_UO0_packet(), code_UO1_packet(), code_UO2_packet(), PACKET_IR, PACKET_IR_DYN, generic_tmp_variables::packet_type, PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, rohc_debugf, c_context::specific, and c_generic_context::tmp_variables.

Referenced by c_generic_encode(), and uncompressed_code_packet().

int code_UO0_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest
	)

Build the UO-0 packet.


      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  :         Add-CID octet         :
    +---+---+---+---+---+---+---+---+
 2  |   first octet of base header  |
    +---+---+---+---+---+---+---+---+
    :                               :
 3  /   0, 1, or 2 octets of CID    /
    :                               :
    +---+---+---+---+---+---+---+---+
 
 UO-0 (5.7.1)
 
      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 0 |      SN       |    CRC    |
    +===+===+===+===+===+===+===+===+

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header such as UDP or UDP-Lite
dest	The rohc-packet-under-build buffer

Returns:: The position in the rohc-packet-under-build buffer if successful, -1 otherwise

References c_context::cid, code_cid_values(), c_generic_context::code_UO_packet_head, code_UO_packet_tail(), c_generic_context::compute_crc_dynamic, c_generic_context::compute_crc_static, CRC_INIT_3, CRC_TYPE_3, ip_packet::data, generic_tmp_variables::max_size, generic_tmp_variables::nr_of_ip_hdr, rohc_debugf, c_generic_context::sn, c_context::specific, and c_generic_context::tmp_variables.

Referenced by code_packet().

int code_UO1_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest
	)

Build the UO-1 packet.

UO-1 and UO-1-ID cannot be used if there is no IPv4 header in the context or if value(RND) and value(RND2) are both 1.


      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  :         Add-CID octet         :
    +---+---+---+---+---+---+---+---+
 2  |   first octet of base header  |
    +---+---+---+---+---+---+---+---+
    :                               :
 3  /   0, 1, or 2 octets of CID    /
    :                               :
    +---+---+---+---+---+---+---+---+
 
 UO-1 (5.11.3):
 
      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   0 |         IP-ID         |
    +===+===+===+===+===+===+===+===+
 4  |        SN         |    CRC    |
    +---+---+---+---+---+---+---+---+

 UO-1-RTP (5.7.3):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   0 |          TS           |
    +===+===+===+===+===+===+===+===+
 4  | M |      SN       |    CRC    |
    +---+---+---+---+---+---+---+---+

 UO-1-ID (5.7.3):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   0 |T=0|      IP-ID        |
    +===+===+===+===+===+===+===+===+
 4  | M |      SN       |    CRC    |
    +---+---+---+---+---+---+---+---+

 UO-1-TS (5.7.3):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   0 |T=1|        TS         |
    +===+===+===+===+===+===+===+===+
 4  | M |      SN       |    CRC    |
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header such as UDP or UDP-Lite
dest	The rohc-packet-under-build buffer

Returns:: The position in the rohc-packet-under-build buffer if successful, -1 otherwise

References c_context::cid, code_cid_values(), c_generic_context::code_UO_packet_head, code_UO_packet_tail(), c_generic_context::compute_crc_dynamic, c_generic_context::compute_crc_static, CRC_INIT_3, CRC_TYPE_3, ip_packet::data, c_profile::id, ipv4_header_info::id_delta, ip_header_info::info, c_generic_context::ip_flags, IPV4, rtp_tmp_variables::m_set, generic_tmp_variables::max_size, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::packet_type, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, c_context::profile, rohc_debugf, ROHC_PROFILE_RTP, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, rtp_tmp_variables::ts_send, ip_header_info::v4, and ip_header_info::version.

Referenced by code_packet().

int code_UO2_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest
	)

Build the UO-2 packet.


      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  :         Add-CID octet         :
    +---+---+---+---+---+---+---+---+
 2  |   first octet of base header  |
    +---+---+---+---+---+---+---+---+
    :                               :
 3  /   0, 1, or 2 octets of CID    /
    :                               :
    +---+---+---+---+---+---+---+---+
 
 UOR-2 (5.11.3):
 
      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |        SN         |
    +===+===+===+===+===+===+===+===+
 5  | X |            CRC            |
    +---+---+---+---+---+---+---+---+

 UOR-2-RTP (5.7.4):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |        TS         |
    +===+===+===+===+===+===+===+===+
 4  | TS| M |       SN              |
    +---+---+---+---+---+---+---+---+
 5  | X |            CRC            |
    +---+---+---+---+---+---+---+---+

 UOR-2-TS (5.7.4):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |        TS         |
    +===+===+===+===+===+===+===+===+
 4  |T=1| M |          SN           |
    +---+---+---+---+---+---+---+---+
 5  | X |           CRC             |
    +---+---+---+---+---+---+---+---+

 UOR-2-ID (5.7.4):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |      IP-ID        |
    +===+===+===+===+===+===+===+===+
 4  |T=0| M |          SN           |
    +---+---+---+---+---+---+---+---+
 5  | X |           CRC             |
    +---+---+---+---+---+---+---+---+

    +---+---+---+---+---+---+---+---+
    :                               :
 6  /           Extension           /
    :                               :
     --- --- --- --- --- --- --- ---

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header such as UDP or UDP-Lite
dest	The rohc-packet-under-build buffer

Returns:: The position in the rohc-packet-under-build buffer if successful, -1 otherwise

References c_context::cid, code_cid_values(), code_EXT0_packet(), code_EXT1_packet(), code_EXT2_packet(), code_EXT3_packet(), c_generic_context::code_UO_packet_head, code_UO_packet_tail(), code_UOR2_bytes(), code_UOR2_ID_bytes(), code_UOR2_RTP_bytes(), code_UOR2_TS_bytes(), c_generic_context::compute_crc_dynamic, c_generic_context::compute_crc_static, CRC_INIT_6, CRC_INIT_7, CRC_TYPE_6, CRC_TYPE_7, ip_packet::data, decide_extension(), extension, c_profile::id, generic_tmp_variables::max_size, generic_tmp_variables::nr_of_ip_hdr, PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2, PACKET_EXT_3, PACKET_NOEXT, generic_tmp_variables::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, rohc_debugf, ROHC_PROFILE_RTP, c_context::specific, and c_generic_context::tmp_variables.

Referenced by code_packet().

int code_UO_packet_tail	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		const unsigned char *	next_header,
		unsigned char *	dest,
		int	counter
	)

Build the tail of the UO packet.


 The general format for the UO packets is:

      0   1   2   3   4   5   6   7
     --- --- --- --- --- --- --- ---
 1  :         Add-CID octet         :                    |
    +---+---+---+---+---+---+---+---+                    |
 2  |   first octet of base header  |                    |
    +---+---+---+---+---+---+---+---+                    |
    :                               :                    |
 3  /   0, 1, or 2 octets of CID    /                    |
    :                               :                    |
    +---+---+---+---+---+---+---+---+                    |
 4  /   remainder of base header    /                    |
    +---+---+---+---+---+---+---+---+                    |
    :                               :                    |
 5  /           Extension           /                    |
    :                               :                    |
     --- --- --- --- --- --- --- ---                     |
    :                               :                    |
 6  +   IP-ID of outer IPv4 header  +
    :                               :     (see section 5.7 or [RFC-3095])
     --- --- --- --- --- --- --- ---
 7  /    AH data for outer list     /                    |
     --- --- --- --- --- --- --- ---                     |
    :                               :                    |
 8  +         GRE checksum          +                    |
    :                               :                    |
     --- --- --- --- --- --- --- ---                     |
    :                               :                    |
 9  +   IP-ID of inner IPv4 header  +                    |
    :                               :                    |
     --- --- --- --- --- --- --- ---                     |
 10 /    AH data for inner list     /                    |
     --- --- --- --- --- --- --- ---                     |
    :                               :                    |
 11 +         GRE checksum          +                    |
    :                               :                    |
     --- --- --- --- --- --- --- ---
    :            List of            :
 12 /        Dynamic chains         /  variable, given by static chain
    :   for additional IP headers   :  (includes no SN)
     --- --- --- --- --- --- --- ---

     --- --- --- --- --- --- --- ---
    :                               :  RTP/UDP profiles only [RFC-3095]
 13 +         UDP Checksum          +  2 octets,
    :                               :  if context(UDP Checksum) != 0
     --- --- --- --- --- --- --- ---

Parts 7, 8, 10, 11 and 12 are not supported. Parts 1, 2, 3, 4 and 5 are built in packet-specific functions. Parts 6 and 9 are built in this function. Part 13 is built in profile-specific function.

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header
next_header	The next header such as UDP or UDP-Lite
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

References c_generic_context::code_UO_packet_tail, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, ip_get_version(), IPV4, ipv4_get_id(), generic_tmp_variables::nr_of_ip_hdr, ipv4_header_info::rnd, rohc_debugf, c_context::specific, c_generic_context::tmp_variables, and ip_header_info::v4.

Referenced by code_UO0_packet(), code_UO1_packet(), and code_UO2_packet().

int code_UOR2_bytes	(	struct c_context *	context,
		int	extension,
		unsigned char *	f_byte,
		unsigned char *	s_byte,
		unsigned char *	t_byte
	)

Code some fields of the UOR-2 packet.

This function is called by code_UO2_packet. It should not be called directly.

See also:: code_UO2_packet


 UOR-2 (5.11.3):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |        SN         |
    +===+===+===+===+===+===+===+===+
 5  | X |            CRC            |
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
extension	The extension that will be appended to the packet
f_byte	IN/OUT: The first byte of the UOR-2 packet
s_byte	IN/OUT: Not used by the UOR-2 packet
t_byte	IN/OUT: The second byte of the UOR-2 packet

Returns:: 1 if successful, 0 otherwise

References generic_tmp_variables::nr_sn_bits, PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2, PACKET_EXT_3, PACKET_NOEXT, rohc_debugf, c_generic_context::sn, c_context::specific, and c_generic_context::tmp_variables.

Referenced by code_UO2_packet().

int code_UOR2_ID_bytes	(	struct c_context *	context,
		int	extension,
		unsigned char *	f_byte,
		unsigned char *	s_byte,
		unsigned char *	t_byte
	)

Code some fields of the UOR-2-ID packet.

This function is called by code_UO2_packet. It should not be called directly.

See also:: code_UO2_packet


 UOR-2-ID (5.7.4):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |      IP-ID        |
    +===+===+===+===+===+===+===+===+
 4  |T=0| M |          SN           |
    +---+---+---+---+---+---+---+---+
 5  | X |           CRC             |
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
extension	The extension that will be appended to the packet
f_byte	IN/OUT: The first byte of the UOR-2-ID packet
s_byte	IN/OUT: The second byte of the UOR-2-ID packet
t_byte	IN/OUT: The third byte of the UOR-2-ID packet

Returns:: 1 if successful, 0 otherwise

References ipv4_header_info::id_delta, ip_header_info::info, c_generic_context::ip_flags, is_deductible(), m, rtp_tmp_variables::m_set, MAX_BITS_IN_4_BYTE_SDVL, generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, rtp_tmp_variables::nr_ts_bits_ext3, PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2, PACKET_EXT_3, PACKET_NOEXT, rohc_debugf, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, sc_rtp_context::ts_sc, rtp_tmp_variables::ts_send, and ip_header_info::v4.

Referenced by code_UO2_packet().

int code_UOR2_RTP_bytes	(	struct c_context *	context,
		int	extension,
		unsigned char *	f_byte,
		unsigned char *	s_byte,
		unsigned char *	t_byte
	)

Code some fields of the UOR-2-RTP packet.

This function is called by code_UO2_packet. It should not be called directly.

See also:: code_UO2_packet


 UOR-2-RTP (5.7.4):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |        TS         |
    +===+===+===+===+===+===+===+===+
 4  | TS| M |       SN              |
    +---+---+---+---+---+---+---+---+
 5  | X |            CRC            |
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
extension	The extension that will be appended to the packet
f_byte	IN/OUT: The first byte of the UOR-2-RTP packet
s_byte	IN/OUT: The second byte of the UOR-2-RTP packet
t_byte	IN/OUT: The third byte of the UOR-2-RTP packet

Returns:: 1 if successful, 0 otherwise

References m, rtp_tmp_variables::m_set, MAX_BITS_IN_4_BYTE_SDVL, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, rtp_tmp_variables::nr_ts_bits_ext3, PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2, PACKET_EXT_3, PACKET_NOEXT, rohc_debugf, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, and rtp_tmp_variables::ts_send.

Referenced by code_UO2_packet().

int code_UOR2_TS_bytes	(	struct c_context *	context,
		int	extension,
		unsigned char *	f_byte,
		unsigned char *	s_byte,
		unsigned char *	t_byte
	)

Code some fields of the UOR-2-TS packet.

This function is called by code_UO2_packet. It should not be called directly.

See also:: code_UO2_packet


 UOR-2-TS (5.7.4):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   1   0 |        TS         |
    +===+===+===+===+===+===+===+===+
 4  |T=1| M |          SN           |
    +---+---+---+---+---+---+---+---+
 5  | X |           CRC             |
    +---+---+---+---+---+---+---+---+

Parameters:

context	The compression context
extension	The extension that will be appended to the packet
f_byte	IN/OUT: The first byte of the UOR-2-TS packet
s_byte	IN/OUT: The second byte of the UOR-2-TS packet
t_byte	IN/OUT: The third byte of the UOR-2-TS packet

Returns:: 1 if successful, 0 otherwise

References m, rtp_tmp_variables::m_set, MAX_BITS_IN_4_BYTE_SDVL, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, rtp_tmp_variables::nr_ts_bits_ext3, PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2, PACKET_EXT_3, PACKET_NOEXT, rohc_debugf, c_generic_context::sn, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, and rtp_tmp_variables::ts_send.

Referenced by code_UO2_packet().

void create_ipv6_item	(	unsigned char *	ext,
		int	index_table,
		int	size,
		struct list_comp *	comp
	)

Update an IPv6 item with the extension.

Parameters:

ext	the extension
index_table	The index of this item in the based table
size	The size of the data
comp	The list compressor

References item::ahhdr, list_comp::based_table, item::data, item::dest, item::hbh, item::header, list_elt::index_table, ip6_ahhdr::ip6ah_len, ip6_ahhdr::ip6ah_nxt, item::length, rohc_debugf, item::rthdr, and zfree.

Referenced by c_init_header_info().

int decide_algo	(	struct rohc_comp *	comp,
		struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		int	packet,
		int	size_data
	)

Decision Algorithm which returns the type of the packet to send when the jamming option is activated. It is an optimisation of the use of the encapsulation packets.

Parameters:

comp	The rohc compressor
context	The context used for the compression
ip	The packet to compress
ip2	The inner ip packet
packet	The type of the original ROHC packet
size_data	The size of the data to send in bytes

Returns:: the new type of the ROHC packet to send (0 if failed)

References rohc_comp::adapt_size, c_assessment_size(), c_context::compressor, rohc_comp::encap_size, ip_packet::header, c_profile::id, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, ip_get_version(), IPV4, IPV6, IPV6_EXT_AUTH, IPV6_EXT_DESTINATION, IPV6_EXT_HOP_BY_HOP, IPV6_EXT_ROUTING, generic_tmp_variables::nr_of_ip_hdr, PACKET_IR, PACKET_IR_DYN, PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, ipv4_header_info::rnd, rohc_debugf, ROHC_PROFILE_RTP, c_context::specific, c_generic_context::tmp_variables, ip_header_info::v4, ip_packet::v6, and ip_header_info::version.

Referenced by decide_packet().

int decide_extension ( struct c_context * context )

Decide what extension shall be used in the UO-2 packet.

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

Parameters:

context The compression context

Returns:: The extension code among PACKET_NOEXT, PACKET_EXT_0, PACKET_EXT_1 and PACKET_EXT_3 if successful, -1 otherwise

References c_profile::id, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, IPV4, is_deductible(), generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_ip_id_bits2, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, PACKET_EXT_0, PACKET_EXT_1, PACKET_EXT_2, PACKET_EXT_3, PACKET_NOEXT, generic_tmp_variables::packet_type, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, ipv4_header_info::rnd, rohc_debugf, ROHC_PROFILE_RTP, generic_tmp_variables::send_dynamic, rtp_tmp_variables::send_rtp_dynamic, generic_tmp_variables::send_static, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, sc_rtp_context::ts_sc, ip_header_info::v4, and ip_header_info::version.

Referenced by code_UO2_packet().

int decide_FO_packet ( struct c_context * 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 PACKET_IR_DYN and PACKET_UOR_2

References c_profile::id, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, IPV4, c_generic_context::ir_dyn_count, MAX_BITS_IN_4_BYTE_SDVL, MAX_FO_COUNT, generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_ip_id_bits2, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, PACKET_IR_DYN, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, ipv4_header_info::rnd, ROHC_PROFILE_RTP, generic_tmp_variables::send_dynamic, generic_tmp_variables::send_static, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, ip_header_info::v4, and ip_header_info::version.

Referenced by decide_packet().

int decide_packet	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2,
		int	size_data
	)

Decide which packet to send when in the different states.

In IR state, IR packets are used. In FO and SO, the decide_FO_packet and decide_SO_packet are used to decide which packet to send.

See also:: decide_FO_packet; decide_SO_packet

Parameters:

context	The compression context
ip	The ip packet to compress
ip2	The inner ip packet
size_data	The size of the data in bytes

Returns:: The packet type among PACKET_IR, PACKET_IR_DYN, PACKET_UO_0, PACKET_UO_1 and PACKET_UOR_2

References c_algo_list_compress(), c_context::compressor, decide_algo(), decide_FO_packet(), decide_SO_packet(), ipv6_header_info::ext_comp, FO, c_generic_context::fo_count, ip_packet::header, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, IPV6, IPV6_EXT_AUTH, IPV6_EXT_DESTINATION, IPV6_EXT_HOP_BY_HOP, IPV6_EXT_ROUTING, IR, c_generic_context::ir_count, rohc_comp::jam_use, list_comp::list_compress, generic_tmp_variables::nr_of_ip_hdr, PACKET_IR, PACKET_IR_DYN, rohc_debugf, SO, c_generic_context::so_count, c_context::specific, c_context::state, c_generic_context::tmp_variables, list_comp::update_done, ip_packet::v6, ip_header_info::v6, and ip_header_info::version.

Referenced by c_generic_encode().

int decide_SO_packet ( const struct c_context * 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 PACKET_UO_0, PACKET_UO_1 and PACKET_UOR_2

References c_profile::id, ip_header_info::info, c_generic_context::ip2_flags, c_generic_context::ip_flags, IPV4, is_deductible(), rtp_tmp_variables::m_set, MAX_BITS_IN_4_BYTE_SDVL, generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_ip_id_bits2, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, PACKET_UO_0, PACKET_UO_1, PACKET_UO_1_ID, PACKET_UO_1_RTP, PACKET_UO_1_TS, PACKET_UOR_2, PACKET_UOR_2_ID, PACKET_UOR_2_RTP, PACKET_UOR_2_TS, c_context::profile, ipv4_header_info::rnd, rohc_debugf, ROHC_PROFILE_RTP, c_context::specific, c_generic_context::specific, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, sc_rtp_context::ts_sc, ip_header_info::v4, and ip_header_info::version.

Referenced by decide_packet().

void decide_state ( struct c_context * 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

References change_state(), FO, c_generic_context::fo_count, IR, c_generic_context::ir_count, MAX_FO_COUNT, MAX_IR_COUNT, c_context::mode, periodic_down_transition(), generic_tmp_variables::send_dynamic, generic_tmp_variables::send_static, SO, c_context::specific, c_context::state, c_generic_context::tmp_variables, and U_MODE.

Referenced by c_generic_create(), c_udp_lite_create(), rtp_decide_state(), and udp_decide_state().

int decide_type ( struct list_comp * comp )

Decide the encoding type for compression list.

Parameters:

comp	The list compressor

Returns:: the encoding type

References list_comp::curr_list, get_elt(), list_elt::index_table, list_elt::item, c_translation::known, list_comp::ref_list, size_list(), list_comp::trans_table, and type_is_present().

Referenced by encode_list().

int encode_list	(	struct list_comp *	comp,
		unsigned char *	dest,
		int	counter,
		int	ps,
		int	size
	)

Generique encoding of compressed list.

Parameters:

comp	the list compressor
dest	The ROHC packet under build
counter	The current position in the rohc-packet-under-build buffer
ps	the size of the index
size	The number of element in current list

Returns:: The new position

References list_comp::curr_list, decide_type(), encode_type_0(), encode_type_1(), encode_type_2(), encode_type_3(), c_list::first_elt, c_list::gen_id, get_elt(), list_elt::index_table, list_comp::islist, list_comp::list_compress, list_comp::ref_list, and rohc_debugf.

Referenced by code_ipv6_dynamic_part().

int encode_type_0	(	struct list_comp *	comp,
		unsigned char *	dest,
		int	counter,
		int	ps
	)

build Encoding type 0

 
Encoding type 0 (5.8.6.1):

       0   1   2   3   4   5   6   7
      --- --- --- --- --- --- --- ---
     | ET = 0| GP| PS|   CC = m      |  
     +---+---+---+---+---+---+---+---+
     |            gen_id             |
     +---+---+---+---+---+---+---+---+
     |       XI 1, ..., XI m         | m octets, or m * 4 bits
     /               --- --- --- --- /  
     |               :    Padding    : if PS = 0 and m is odd
     +---+---+---+---+---+---+---+---+
     |                               |
     /      item 1, ..., item n      / variable length
     |                               |
     +---+---+---+---+---+---+---+---+

Parameters:

comp	the list compressor
dest	The ROHC packet under build
counter	The current position in the rohc-packet-under-build buffer
ps	the size of the index

Returns:: The new position

References list_comp::curr_list, item::data, c_list::gen_id, get_elt(), list_elt::index_table, list_elt::item, c_translation::known, item::length, rohc_debugf, size_list(), and list_comp::trans_table.

Referenced by encode_list().

int encode_type_1	(	struct list_comp *	comp,
		unsigned char *	dest,
		int	counter,
		int	ps
	)

build Encoding type 1


Encoding type 1 (5.8.6.2):

	  0   1   2   3   4   5   6   7
	 --- --- --- --- --- --- --- ---
	| ET = 1| GP| PS|     XI 1      |
	+---+---+---+---+---+---+---+---+
	|            gen_id             |
	+---+---+---+---+---+---+---+---+
	|            ref_id             |
	+---+---+---+---+---+---+---+---+
	/       insertion bit mask      /
	+---+---+---+---+---+---+---+---+
	|           XI list             | k octets, or (k-1)*4 bits
	/               --- --- --- --- /
	|               :    Padding    : if PS = 0 and k is even
	+---+---+---+---+---+---+---+---+
	|                               |
	/      item 1, ..., item n      / variable length
	|                               |
	+---+---+---+---+---+---+---+---+

Parameters:

comp	the list compressor
dest	The ROHC packet under build
counter	The current position in the rohc-packet-under-build buffer
ps	the size of the index

Returns:: The new position

References list_comp::curr_list, item::data, get_elt(), list_elt::index_table, list_elt::item, c_translation::known, item::length, list_comp::ref_list, size_list(), list_comp::trans_table, and type_is_present().

Referenced by encode_list().

int encode_type_2	(	struct list_comp *	comp,
		unsigned char *	dest,
		int	counter,
		int	ps
	)

build Encoding type 2


Encoding type 2 (5.8.6.3):

	  0   1   2   3   4   5   6   7
	+---+---+---+---+---+---+---+---+
	| ET = 2| GP| PS|    Counter    |
	+---+---+---+---+---+---+---+---+
	|            gen_id             |
	+---+---+---+---+---+---+---+---+
	|            ref_id             |
	+---+---+---+---+---+---+---+---+
	/        removal bit mask       /
	+---+---+---+---+---+---+---+---+

Parameters:

comp	the list compressor
dest	The ROHC packet under build
counter	The current position in the rohc-packet-under-build buffer
ps	the size of the index

Returns:: The new position

References list_comp::curr_list, get_elt(), list_elt::item, list_comp::ref_list, rohc_debugf, size_list(), and type_is_present().

Referenced by encode_list().

int encode_type_3	(	struct list_comp *	comp,
		unsigned char *	dest,
		int	counter,
		int	ps
	)

build Encoding type 3


Encoding type 3 (5.8.6.4):

	  0   1   2   3   4   5   6   7
	+---+---+---+---+---+---+---+---+
	| ET = 2| GP| PS|     XI 1      |
	+---+---+---+---+---+---+---+---+
	|            gen_id             |
	+---+---+---+---+---+---+---+---+
	|            ref_id             |
	+---+---+---+---+---+---+---+---+
	/        removal bit mask       /
	+---+---+---+---+---+---+---+---+
	/       insertion bit mask      /
        +---+---+---+---+---+---+---+---+
	|           XI list             | k octets, or (k-1)*4 bits
	/               --- --- --- --- /
	|               :    Padding    : if PS = 0 and k is even
	+---+---+---+---+---+---+---+---+
	|                               |
	/      item 1, ..., item n      / variable length
	|                               |
	+---+---+---+---+---+---+---+---+

Parameters:

comp	the list compressor
dest	The ROHC packet under build
counter	The current position in the rohc-packet-under-build buffer
ps	the size of the index

Returns:: The new position

References list_comp::curr_list, item::data, GET_BIT_0_2, GET_BIT_3, get_elt(), GET_REAL, list_elt::index_table, list_elt::item, c_translation::known, item::length, list_comp::ref_list, rohc_debugf, size_list(), list_comp::trans_table, and type_is_present().

Referenced by encode_list().

int get_index_ipv6_table	(	const struct ip_packet	ip,
		int	index
	)

Return the based table index for the Nth IP extension of the IP packet.

Parameters:

ip	The IP packet to analyse
index	The index of the extension to retrieve in the IP packet

Returns:: the based table index

References list_elt::index_table, ip_get_next_ext_header_from_ext(), ip_get_next_ext_header_from_ip(), IPV6_EXT_AUTH, IPV6_EXT_DESTINATION, IPV6_EXT_HOP_BY_HOP, and IPV6_EXT_ROUTING.

Referenced by c_init_header_info().

int get_ipv6_ext_size ( unsigned char * ext )

Get the size of the IPv6 extension.

Parameters:

ext	The extension

Returns:: the size

Referenced by c_init_header_info().

unsigned char * get_ipv6_extension	(	const struct ip_packet	ip,
		int	index
	)

Extract the Nth IP extension of the IP packet.

Extract the IP extension at the given index.

Parameters:

ip	The IP packet to analyse
index	The index of the extension to retrieve in the IP packet

Returns:: the extension

References ip_get_next_ext_header_from_ext(), and ip_get_next_ext_header_from_ip().

Referenced by c_init_header_info().

int header_fields	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		unsigned short	changed_f,
		const struct ip_packet	ip,
		boolean	is_outer,
		int	nr_ip_id_bits,
		unsigned char *	dest,
		int	counter
	)

Build inner or outer IP header fields.

This function is used to code the IP header fields of the extension 3 of the UO-2 packet. The function is called twice (one for inner IP header and one for outer IP header) with different arguments.

See also:: code_EXT3_packet


    +-----+-----+-----+-----+-----+-----+-----+-----+
 1  |         Type of Service/Traffic Class         |  if TOS = 1
     ..... ..... ..... ..... ..... ..... ..... .....
 2  |         Time to Live/Hop Limit                |  if TTL = 1
     ..... ..... ..... ..... ..... ..... ..... .....
 3  |         Protocol/Next Header                  |  if PR = 1
     ..... ..... ..... ..... ..... ..... ..... .....
 4  /         IP extension headers                  /  variable, if IPX = 1
     ..... ..... ..... ..... ..... ..... ..... .....
 
    IP-ID is coded here for outer header fields although it doesn't look that
    way in the extension 3 picture in 5.7.5 and 5.11.4 of RFC 3095.
    +-----+-----+-----+-----+-----+-----+-----+-----+
 5  |                  IP-ID                        |  2 octets, if I = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+

Part 4 is not supported.

Parameters:

context	The compression context
header_info	The header info stored in the profile
changed_f	The fields that changed, created by the function changed_fields
ip	One inner or outer IP header
is_outer	Whether the IP header is the outer header or not
nr_ip_id_bits	The number of bits needed to transmit the IP-ID field
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

See also:: changed_fields

References ip_header_info::info, ip_get_protocol(), ip_get_tos(), ip_get_ttl(), IPV4, ipv4_get_id_nbo(), is_changed(), MAX_FO_COUNT, MOD_PROTOCOL, MOD_TOS, MOD_TTL, ipv4_header_info::nbo, ip_header_info::protocol_count, ipv4_header_info::rnd, ipv4_header_info::rnd_count, rohc_debugf, ip_header_info::tos_count, ip_header_info::ttl_count, ip_header_info::v4, and ip_header_info::version.

Referenced by code_EXT3_packet().

int header_flags	(	struct c_context *	context,
		struct ip_header_info *	header_info,
		unsigned short	changed_f,
		const struct ip_packet	ip,
		boolean	is_outer,
		int	nr_ip_id_bits,
		unsigned char *	dest,
		int	counter
	)

Build inner or outer IP header flags.

This function is used to code the IP header fields of the extension 3 of the UO-2 packet. The function is called twice (one for inner IP header and one for outer IP header) with different arguments.

See also:: code_EXT3_packet


 Header flags for IP and UDP profiles (5.11.4):

 For inner flags:
 
    +-----+-----+-----+-----+-----+-----+-----+-----+
 1  |            Inner IP header flags        |     |  if ip = 1
    | TOS | TTL | DF  | PR  | IPX | NBO | RND | 0** |  0** reserved
    +-----+-----+-----+-----+-----+-----+-----+-----+
 
 or for outer flags:
 
    +-----+-----+-----+-----+-----+-----+-----+-----+
 2  |            Outer IP header flags              |
    | TOS2| TTL2| DF2 | PR2 |IPX2 |NBO2 |RND2 |  I2 |  if ip2 = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+

Parameters:

context	The compression context
header_info	The header info stored in the profile
changed_f	The fields that changed, created by the function changed_fields
ip	One inner or outer IP header
is_outer	Whether the IP header is the outer header or not
nr_ip_id_bits	The number of bits needed to transmit the IP-ID field
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

See also:: changed_fields

References ipv4_header_info::df_count, ip_header_info::info, IPV4, ipv4_get_df(), is_changed(), MAX_FO_COUNT, MOD_PROTOCOL, MOD_TOS, MOD_TTL, ipv4_header_info::nbo, ipv4_header_info::nbo_count, ip_header_info::protocol_count, ipv4_header_info::rnd, ipv4_header_info::rnd_count, rohc_debugf, ip_header_info::tos_count, ip_header_info::ttl_count, ip_header_info::v4, and ip_header_info::version.

Referenced by code_EXT3_packet().

void ip6_c_init_table ( struct list_comp * comp )

Initialize the tables IPv6 extension in compressor.

Parameters:

comp	The list compressor

References AH, item::ahhdr, list_comp::based_table, c_translation::counter, item::data, DEST, item::dest, HBH, item::hbh, item::header, c_translation::item, c_translation::known, item::length, RTHDR, item::rthdr, list_comp::trans_table, and item::type.

Referenced by c_init_header_info().

int ipv6_compare	(	unsigned char *	ext,
		struct list_comp *	comp,
		int	size,
		int	index_table
	)

Ipv6 extension comparison.

Parameters:

ext	The extensiom
comp	the list compressor
size	The size to compare
index_table	The index in based table

Returns:: 1 if equal, 0 else

References list_comp::based_table, and item::data.

Referenced by c_init_header_info().

boolean is_changed	(	unsigned short	changed_fields,
		unsigned short	check_field
	)		`[inline]`

Check if a specified IP field has changed.

Parameters:

changed_fields	The fields that changed, created by the function changed_fields
check_field	The field for which to check a change

Returns:: Whether the field changed or not

See also:: changed_fields

Referenced by changed_dynamic_one_hdr(), changed_static_one_hdr(), header_fields(), and header_flags().

void periodic_down_transition ( struct c_context * context )

Periodically change the context state after a certain number of packets.

Parameters:

context The compression context

References change_state(), CHANGE_TO_FO_COUNT, CHANGE_TO_IR_COUNT, FO, c_generic_context::go_back_fo_count, c_generic_context::go_back_ir_count, IR, c_generic_context::ir_dyn_count, rohc_debugf, SO, c_context::specific, and c_context::state.

Referenced by decide_state().

int rtp_header_flags_and_fields	(	struct c_context *	context,
		unsigned short	changed_f,
		const struct ip_packet	ip,
		unsigned char *	dest,
		int	counter
	)

void update_variables	(	struct c_context *	context,
		const struct ip_packet	ip,
		const struct ip_packet	ip2
	)

Update some context variables.

This function is only used in encode. Everything in this function could be in encode but to make it more readable we have it here instead.

Parameters:

context	The compression context
ip	The outer IP header
ip2	The inner IP header

References add_scaled(), c_add_wlsb(), c_get_k_wlsb(), get_ts_scaled(), c_profile::id, ipv4_header_info::id_delta, ip_header_info::info, INIT_STRIDE, c_generic_context::ip2_flags, c_generic_context::ip_flags, ip_get_next_layer(), ip_get_version(), ipv4_header_info::ip_id_window, IPV4, ipv4_get_id(), nb_bits_scaled(), ipv4_header_info::nbo, generic_tmp_variables::nr_ip_id_bits, generic_tmp_variables::nr_ip_id_bits2, generic_tmp_variables::nr_of_ip_hdr, generic_tmp_variables::nr_sn_bits, rtp_tmp_variables::nr_ts_bits, c_context::profile, rohc_debugf, ROHC_PROFILE_RTP, SEND_SCALED, c_generic_context::sn, c_generic_context::sn_window, c_context::specific, c_generic_context::specific, ts_sc_comp::state, rtphdr::timestamp, sc_rtp_context::tmp_variables, c_generic_context::tmp_variables, sc_rtp_context::ts_sc, rtp_tmp_variables::ts_send, and ip_header_info::v4.

Referenced by c_generic_encode().

Variable Documentation

const char* generic_extension_types[]

Initial value:

{
        "NOEXT",
        "EXT0",
        "EXT1",
        "EXT2",
        "EXT3",
}

The description of the different extensions for the UO-2 packet.

const char* generic_packet_types[]

Initial value:

{
        "IR",
        "IRDYN",
        "OU-0",
        "OU-1",
        "OU-2",
}

The description of the different ROHC packets.

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation