rohc_comp_rfc3095.c File Reference

Generic framework for RFC3095-based compression profiles such as IP-only, UDP, UDP-Lite, ESP, and RTP profiles. More...

#include "rohc_comp_rfc3095.h"
#include "c_rtp.h"
#include "rohc_traces.h"
#include "rohc_traces_internal.h"
#include "rohc_debug.h"
#include "rohc_packets.h"
#include "rohc_utils.h"
#include "rohc_bit_ops.h"
#include "schemes/cid.h"
#include "schemes/ip_id_offset.h"
#include "schemes/comp_list_ipv6.h"
#include "sdvl.h"
#include "crc.h"
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include "config.h"
Include dependency graph for rohc_comp_rfc3095.c:

Defines

#define MOD_TOS   0x0001
#define MOD_TTL   0x0010
#define MOD_PROTOCOL   0x0020
#define MOD_IPV6_EXT_LIST_STRUCT   0x0002
#define MOD_IPV6_EXT_LIST_CONTENT   0x0004
#define MOD_ERROR   0x0008

Functions

static bool ip_header_info_new (struct ip_header_info *const header_info, const struct ip_packet *const ip, const size_t list_trans_nr, const size_t wlsb_window_width, rohc_trace_callback2_t trace_cb, void *const trace_cb_priv, const int profile_id)
 Initialize the IP header info stored in the context.
static void ip_header_info_free (struct ip_header_info *const header_info)
 Reset the given IP header info.
static void c_init_tmp_variables (struct generic_tmp_vars *const tmp_vars)
 Initialize all temporary variables stored in the context.
static rohc_packet_t decide_packet (struct rohc_comp_ctxt *const context)
 Decide which packet to send when in the different states.
static rohc_ext_t decide_extension_uor2 (const struct rohc_comp_ctxt *const context, const size_t nr_innermost_ip_id_bits, const size_t nr_outermost_ip_id_bits)
 Decide what extension shall be used in the UOR-2 packet (non-RTP).
static rohc_ext_t decide_extension_uor2rtp (const struct rohc_comp_ctxt *const context, const size_t nr_innermost_ip_id_bits, const size_t nr_outermost_ip_id_bits)
 Decide what extension shall be used in the UOR-2 packet (RTP).
static rohc_ext_t decide_extension_uor2ts (const struct rohc_comp_ctxt *const context, const size_t nr_innermost_ip_id_bits, const size_t nr_outermost_ip_id_bits)
 Decide what extension shall be used in the UO-1-ID/UOR-2 packet.
static rohc_ext_t decide_extension_uor2id (const struct rohc_comp_ctxt *const context, const size_t nr_innermost_ip_id_bits, const size_t nr_outermost_ip_id_bits)
 Decide what extension shall be used in the UOR-2-ID packet.
static rohc_ext_t decide_extension_uo1id (const struct rohc_comp_ctxt *const context, const size_t nr_innermost_ip_id_bits, const size_t nr_outermost_ip_id_bits)
 Decide what extension shall be used in the UO-1-ID packet.
static int code_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the ROHC packet to send.
static int code_IR_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the IR packet.
static int code_IR_DYN_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the IR-DYN packet.
static int rohc_code_static_part (const struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, int counter)
 Build the static part of the IR packet.
static int rohc_code_static_ip_part (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const struct ip_packet *const ip, uint8_t *const dest, int counter)
 Build the static part of one IP header for the IR packet.
static int code_ipv4_static_part (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const struct ip_packet *const ip, uint8_t *const dest, int counter)
 Build the IPv4 static part of the IR packet.
static int code_ipv6_static_part (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const struct ip_packet *const ip, uint8_t *const dest, int counter)
 Build the IPv6 static part of the IR packet.
static int rohc_code_dynamic_part (const struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, int counter)
 Build the dynamic part of the IR and IR-DYN packets.
static int rohc_code_dynamic_ip_part (const struct rohc_comp_ctxt *const context, const unsigned int hdr_pos, struct ip_header_info *const header_info, const struct ip_packet *const ip, uint8_t *const dest, int counter)
 Build the dynamic part of one IP header for the IR/IR-DYN packets.
static int code_ipv4_dynamic_part (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const struct ip_packet *const ip, uint8_t *const dest, int counter)
 Build the IPv4 dynamic part of the IR and IR-DYN packets.
static int code_ipv6_dynamic_part (const struct rohc_comp_ctxt *const context, const unsigned int hdr_pos, struct ip_header_info *const header_info, const struct ip_packet *const ip, uint8_t *const dest, int counter)
 Build the IPv6 dynamic part of the IR and IR-DYN packets.
static int code_uo_remainder (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const dest, int counter)
 Build the tail of the UO packet.
static int code_UO0_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the UO-0 packet.
static int rohc_comp_rfc3095_build_uo1_pkt (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the UO-1 packet for the non-RTP profiles.
static int rohc_comp_rfc3095_build_uo1rtp_pkt (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the UO-1 packet for the RTP profiles.
static int rohc_comp_rfc3095_build_uo1ts_pkt (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the UO-1-TS packet.
static int rohc_comp_rfc3095_build_uo1id_pkt (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the UO-1-ID packet.
static int code_UO2_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len)
 Build the UO-2 packet.
static int code_UOR2_bytes (const struct rohc_comp_ctxt *const context, const rohc_ext_t extension, uint8_t *const f_byte, uint8_t *const s_byte, uint8_t *const t_byte)
 Code some fields of the UOR-2 packet.
static int code_UOR2_RTP_bytes (const struct rohc_comp_ctxt *const context, const rohc_ext_t extension, uint8_t *const f_byte, uint8_t *const s_byte, uint8_t *const t_byte)
 Code some fields of the UOR-2-RTP packet.
static int code_UOR2_TS_bytes (const struct rohc_comp_ctxt *const context, const rohc_ext_t extension, uint8_t *const f_byte, uint8_t *const s_byte, uint8_t *const t_byte)
 Code some fields of the UOR-2-TS packet.
static int code_UOR2_ID_bytes (const struct rohc_comp_ctxt *const context, const rohc_ext_t extension, uint8_t *const f_byte, uint8_t *const s_byte, uint8_t *const t_byte)
 Code some fields of the UOR-2-ID packet.
static int code_EXT0_packet (const struct rohc_comp_ctxt *const context, uint8_t *const dest, int counter)
 Build the extension 0 of the UO-2 packet.
static int code_EXT1_packet (const struct rohc_comp_ctxt *const context, uint8_t *const dest, int counter)
 Build the extension 1 of the UO-2 packet.
static int code_EXT2_packet (const struct rohc_comp_ctxt *const context, uint8_t *const dest, int counter)
 Build the extension 2 of the UO-2 packet.
static int code_EXT3_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const dest, int counter)
 Build the extension 3 of the UO* packet types.
static int code_EXT3_rtp_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const dest, int counter)
 Build the extension 3 of the UO-2 packet.
static int code_EXT3_nortp_packet (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const dest, int counter)
 Build the extension 3 of the UO-2 packet.
static int rtp_header_flags_and_fields (const struct rohc_comp_ctxt *const context, const struct ip_packet *const ip, uint8_t *const dest, int counter)
static int header_flags (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const unsigned short changed_f, const struct ip_packet *const ip, const int ip2_or_I2, uint8_t *const dest, int counter)
 Build inner or outer IP header flags.
static int header_fields (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const unsigned short changed_f, const struct ip_packet *const ip, const int I, const ip_header_pos_t ip_hdr_pos, uint8_t *const dest, int counter)
 Build inner or outer IP header fields.
static uint8_t compute_uo_crc (const struct rohc_comp_rfc3095_ctxt *rfc3095_ctxt, const struct net_pkt *const uncomp_pkt, const rohc_crc_type_t crc_type, const uint8_t crc_init, const uint8_t *const crc_table)
 Compute the CRC for a UO* packet.
static void update_context (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Update the compression context with the successfully compressed packet.
static void update_context_ip_hdr (struct ip_header_info *const ip_flags, const struct ip_packet *const ip)
 Update the IP information with the IP header.
static bool rohc_comp_rfc3095_detect_changes (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Detect changes between packet and context.
static int changed_static_both_hdr (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Check if the static parts of the context changed in any of the two IP headers.
static int changed_static_one_hdr (struct rohc_comp_ctxt *const context, const unsigned short changed_fields, struct ip_header_info *const header_info)
 Check if the static part of the context changed in the new IP packet.
static int changed_dynamic_both_hdr (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Check if the dynamic parts of the context changed in any of the two IP headers.
static int changed_dynamic_one_hdr (struct rohc_comp_ctxt *const context, const unsigned short changed_fields, struct ip_header_info *const header_info, const struct ip_packet *const ip)
 Check if the dynamic part of the context changed in the IP packet.
static unsigned short detect_changed_fields (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info,const struct ip_packet *const ip)
 Find the IP fields that changed between the profile and a new IP packet.
static bool is_field_changed (const unsigned short changed_fields, const unsigned short check_field)
 Check if a specified IP field has changed.
static void detect_ip_id_behaviours (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Detect the behaviour of the IP-ID fields of the IPv4 headers.
static void detect_ip_id_behaviour (const struct rohc_comp_ctxt *const context, struct ip_header_info *const header_info, const struct ip_packet *const ip)
 Detect the behaviour of the IP-ID field of the given IPv4 header.
static bool encode_uncomp_fields (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Encode uncompressed fields with the corresponding encoding scheme.
static void rohc_get_innermost_ipv4_non_rnd (const struct rohc_comp_ctxt *const context, ip_header_pos_t *const pos, size_t *const nr_bits, uint16_t *const offset)
 Determine the number of IP-ID bits and the IP-ID offset of the innermost IPv4 header with non-random IP-ID.
static void rohc_comp_rfc3095_get_ext3_I_flags (const struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, const rohc_packet_t packet_type, const size_t nr_ip_id_bits, const size_t nr_ip_id_bits2, ip_header_pos_t *const innermost_ipv4_non_rnd, uint8_t *const I, uint8_t *const I2)
 Determine the values of the I and I2 flags for UO* extension 3.
static bool rohc_comp_rfc3095_feedback_2 (struct rohc_comp_ctxt *const context, const uint8_t *const packet, const size_t packet_len, const uint8_t *const feedback_data, const size_t feedback_data_len)
 Update the profile when FEEDBACK-2 is received.
static void rohc_comp_rfc3095_feedback_ack (struct rohc_comp_ctxt *const context, const uint32_t sn_bits, const size_t sn_bits_nr, const bool sn_not_valid)
 Perform the required actions after the reception of a positive ACK.
bool rohc_comp_rfc3095_create (struct rohc_comp_ctxt *const context, const rohc_lsb_shift_t sn_shift, const struct net_pkt *const packet)
 Create a new context and initialize it thanks to the given IP packet.
void rohc_comp_rfc3095_destroy (struct rohc_comp_ctxt *const context)
 Destroy the context.
bool rohc_comp_rfc3095_check_profile (const struct rohc_comp *const comp, const struct net_pkt *const packet)
 Check if the given packet corresponds to an IP-based profile.
int rohc_comp_rfc3095_encode (struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt, uint8_t *const rohc_pkt, const size_t rohc_pkt_max_len, rohc_packet_t *const packet_type, size_t *const payload_offset)
 Encode an IP packet according to a pattern decided by several different factors.
bool rohc_comp_rfc3095_feedback (struct rohc_comp_ctxt *const context, const enum rohc_feedback_type feedback_type, const uint8_t *const packet, const size_t packet_len, const uint8_t *const feedback_data, const size_t feedback_data_len)
 Update the profile when feedback is received.
void rohc_comp_rfc3095_decide_state (struct rohc_comp_ctxt *const context)
 Decide the state that should be used for the next packet.
rohc_ext_t decide_extension (const struct rohc_comp_ctxt *const context)
 Decide what extension shall be used in the UO-1-ID/UOR-2 packet.
void rohc_get_ipid_bits (const struct rohc_comp_ctxt *const context, size_t *const nr_innermost_bits, size_t *const nr_outermost_bits)
 Get the number of non-random outer/inner IP-ID bits.
bool rohc_comp_rfc3095_is_sn_possible (const struct rohc_comp_rfc3095_ctxt *const rfc3095_ctxt, const size_t bits_nr, const size_t add_bits_nr)
 Are the given SN field sizes possible?

Detailed Description

Generic framework for RFC3095-based compression profiles such as IP-only, UDP, UDP-Lite, ESP, and RTP profiles.

Author:
Didier Barvaux <didier.barvaux@toulouse.viveris.com>
Didier Barvaux <didier@barvaux.org>
David Moreau from TAS
Emmanuelle Pechereau <epechereau@toulouse.viveris.com>

Define Documentation

#define MOD_ERROR   0x0008

A flag to indicate that an errror occurred

#define MOD_IPV6_EXT_LIST_CONTENT   0x0004

A flag to indicate that the content of the IPv6 extension headers list changed in IP header

#define MOD_IPV6_EXT_LIST_STRUCT   0x0002

A flag to indicate that the structure of the IPv6 extension headers list changed in IP header

#define MOD_PROTOCOL   0x0020

A flag to indicate that the IPv4 Protocol field changed in IP header

#define MOD_TOS   0x0001

A flag to indicate that IPv4 Type Of Service field changed in IP header

#define MOD_TTL   0x0010

A flag to indicate that IPv4 Time To Live field changed in IP header

Function Documentation

static void c_init_tmp_variables ( struct generic_tmp_vars *const   tmp_vars  )  [static]

Initialize all temporary variables stored in the context.

Parameters:
tmp_vars The temporary variables to initialize
static int changed_dynamic_both_hdr ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

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

Parameters:
context The compression context
uncomp_pkt The uncompressed packet
Returns:
The number of dynamic fields that changed
static int changed_dynamic_one_hdr ( struct rohc_comp_ctxt *const   context,
const unsigned short  changed_fields,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip 
) [static]

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.

Although 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?
  • SID: is the IP-ID static?
Parameters:
context The compression context
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
Returns:
The number of fields that changed
static int changed_static_both_hdr ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

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

Parameters:
context The compression context
uncomp_pkt The uncompressed packet
Returns:
The number of static fields that changed
static int changed_static_one_hdr ( struct rohc_comp_ctxt *const   context,
const unsigned short  changed_fields,
struct ip_header_info *const   header_info 
) [static]

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.

Although 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.

Although 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:
context The compression context
changed_fields The fields that changed, created by the function changed_fields
header_info The header info stored in the profile
Returns:
The number of fields that changed
static int code_EXT0_packet ( const struct rohc_comp_ctxt *const   context,
uint8_t *const   dest,
int  counter 
) [static]

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
static int code_EXT1_packet ( const struct rohc_comp_ctxt *const   context,
uint8_t *const   dest,
int  counter 
) [static]

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
static int code_EXT2_packet ( const struct rohc_comp_ctxt *const   context,
uint8_t *const   dest,
int  counter 
) [static]

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
static int code_EXT3_nortp_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   dest,
int  counter 
) [static]

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              |  if ip2 = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
 4  |                      SN                       |  if S = 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
    +-----+-----+-----+-----+-----+-----+-----+-----+
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
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
static int code_EXT3_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   dest,
int  counter 
) [static]

Build the extension 3 of the UO* packet types.

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
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
static int code_EXT3_rtp_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   dest,
int  counter 
) [static]

Build the extension 3 of the UO-2 packet. 


 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              |  if ip2 = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
 4  |                      SN                       |  if S = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 5  /                      TS                       / 1-4 octets, if R-TS = 1
    |                                               |
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 6  /            Inner IP header fields             /  variable,
    |                                               |  if ip = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
 7  |                     IP-ID                     |  2 octets, if I = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |
 8  /            Outer IP header fields             /  variable,
    |                                               |  if ip2 = 1
    +-----+-----+-----+-----+-----+-----+-----+-----+
    |                                               |  variable,
 9  /          RTP Header flags and fields          /  if rtp = 1
    |                                               |
    +-----+-----+-----+-----+-----+-----+-----+-----+
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
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
static int code_ipv4_dynamic_part ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]

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, sent verbatim
    +---+---+---+---+---+---+---+---+
 4  | DF|RND|NBO|SID|       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
static int code_ipv4_static_part ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]

Build the IPv4 static part of the IR packet. 


 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
static int code_ipv6_dynamic_part ( const struct rohc_comp_ctxt *const   context,
const unsigned int  hdr_pos,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]

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
hdr_pos The position of the IP header: 1 for the outer header or 2 for the inner IP header
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, -1 in case of error
static int code_ipv6_static_part ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]

Build the IPv6 static part of the IR packet. 


 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
static int code_IR_DYN_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

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 nor ESP
    +---+---+---+---+---+---+---+---+
    :                               :
    /           Payload             / variable length
    :                               :
     - - - - - - - - - - - - - - - -
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int code_IR_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

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 nor ESP
    +---+---+---+---+---+---+---+---+
    |                               |
    |           Payload             |  variable length
    |                               |
     - - - - - - - - - - - - - - - -
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
int code_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

Build the ROHC packet to send.

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int code_UO0_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

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
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int code_UO2_packet ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

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           /
    :                               :
     --- --- --- --- --- --- --- ---

 X: X = 0 indicates that no extension is present;
    X = 1 indicates that an extension is present.

 T: T = 0 indicates format UOR-2-ID;
    T = 1 indicates format UOR-2-TS.
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int code_uo_remainder ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   dest,
int  counter 
) [static]

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
uncomp_pkt The uncompressed packet to encode
dest The rohc-packet-under-build buffer
counter The current position in the rohc-packet-under-build buffer
Returns:
The new position in the rohc-packet-under-build buffer
static int code_UOR2_bytes ( const struct rohc_comp_ctxt *const   context,
const rohc_ext_t  extension,
uint8_t *const   f_byte,
uint8_t *const   s_byte,
uint8_t *const   t_byte 
) [static]

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
static int code_UOR2_ID_bytes ( const struct rohc_comp_ctxt *const   context,
const rohc_ext_t  extension,
uint8_t *const   f_byte,
uint8_t *const   s_byte,
uint8_t *const   t_byte 
) [static]

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
static int code_UOR2_RTP_bytes ( const struct rohc_comp_ctxt *const   context,
const rohc_ext_t  extension,
uint8_t *const   f_byte,
uint8_t *const   s_byte,
uint8_t *const   t_byte 
) [static]

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
static int code_UOR2_TS_bytes ( const struct rohc_comp_ctxt *const   context,
const rohc_ext_t  extension,
uint8_t *const   f_byte,
uint8_t *const   s_byte,
uint8_t *const   t_byte 
) [static]

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
static uint8_t compute_uo_crc ( const struct rohc_comp_rfc3095_ctxt *  rfc3095_ctxt,
const struct net_pkt *const   uncomp_pkt,
const rohc_crc_type_t  crc_type,
const uint8_t  crc_init,
const uint8_t *const   crc_table 
) [static]

Compute the CRC for a UO* packet.

Parameters:
rfc3095_ctxt The generic compression context
uncomp_pkt The uncompressed packet to encode
crc_type The type of CRC to compute
crc_init The initial value of the CRC
crc_table The table of pre-computed CRC
Returns:
The computed CRC
rohc_ext_t decide_extension ( const struct rohc_comp_ctxt *const   context  ) 

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

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

Parameters:
context The compression context
Returns:
The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3 if successful, ROHC_EXT_UNKNOWN otherwise
static rohc_ext_t decide_extension_uo1id ( const struct rohc_comp_ctxt *const   context,
const size_t  nr_innermost_ip_id_bits,
const size_t  nr_outermost_ip_id_bits 
) [static]

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

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

Parameters:
context The compression context
nr_innermost_ip_id_bits The number of IP-ID bits of the innermost IPv4 header
nr_outermost_ip_id_bits The number of IP-ID bits of the outermost IPv4 header
Returns:
The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3
static rohc_ext_t decide_extension_uor2 ( const struct rohc_comp_ctxt *const   context,
const size_t  nr_innermost_ip_id_bits,
const size_t  nr_outermost_ip_id_bits 
) [static]

Decide what extension shall be used in the UOR-2 packet (non-RTP).

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

Parameters:
context The compression context
nr_innermost_ip_id_bits The number of IP-ID bits of the innermost IPv4 header
nr_outermost_ip_id_bits The number of IP-ID bits of the outermost IPv4 header
Returns:
The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3
static rohc_ext_t decide_extension_uor2id ( const struct rohc_comp_ctxt *const   context,
const size_t  nr_innermost_ip_id_bits,
const size_t  nr_outermost_ip_id_bits 
) [static]

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

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

Parameters:
context The compression context
nr_innermost_ip_id_bits The number of IP-ID bits of the innermost IPv4 header
nr_outermost_ip_id_bits The number of IP-ID bits of the outermost IPv4 header
Returns:
The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3
static rohc_ext_t decide_extension_uor2rtp ( const struct rohc_comp_ctxt *const   context,
const size_t  nr_innermost_ip_id_bits,
const size_t  nr_outermost_ip_id_bits 
) [static]

Decide what extension shall be used in the UOR-2 packet (RTP).

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

Parameters:
context The compression context
nr_innermost_ip_id_bits The number of IP-ID bits of the innermost IPv4 header
nr_outermost_ip_id_bits The number of IP-ID bits of the outermost IPv4 header
Returns:
The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3
static rohc_ext_t decide_extension_uor2ts ( const struct rohc_comp_ctxt *const   context,
const size_t  nr_innermost_ip_id_bits,
const size_t  nr_outermost_ip_id_bits 
) [static]

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

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

Parameters:
context The compression context
nr_innermost_ip_id_bits The number of IP-ID bits of the innermost IPv4 header
nr_outermost_ip_id_bits The number of IP-ID bits of the outermost IPv4 header
Returns:
The extension code among ROHC_EXT_NONE, ROHC_EXT_0, ROHC_EXT_1 and ROHC_EXT_3
static rohc_packet_t decide_packet ( struct rohc_comp_ctxt *const   context  )  [static]

Decide which packet to send when in the different states.

In IR state, IR packets are used. In FO and SO, the profile-specific functions are called if they are defined, otherwise IR packets are used.

Parameters:
context The compression context
Returns:
  • The packet type among ROHC_PACKET_IR, ROHC_PACKET_IR_DYN, ROHC_PACKET_UO_0, ROHC_PACKET_UO_1* and ROHC_PACKET_UOR_2* in case of success
  • ROHC_PACKET_UNKNOWN in case of failure
static unsigned short detect_changed_fields ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip 
) [static]

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:
context The compression context
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
static void detect_ip_id_behaviour ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip 
) [static]

Detect the behaviour of the IP-ID field of the given IPv4 header.

Detect how the IP-ID field behave:

  • constant,
  • increase in Network Bit Order (NBO),
  • increase in Little Endian,
  • randomly.
Parameters:
context The compression context
header_info The header info stored in the profile
ip One IPv4 header
static void detect_ip_id_behaviours ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

Detect the behaviour of the IP-ID fields of the IPv4 headers.

Detect how the IP-ID fields behave:

  • constant (not handled yet),
  • increase in Network Bit Order (NBO),
  • increase in Little Endian,
  • randomly.
Parameters:
context The compression context
uncomp_pkt The uncompressed packet
static bool encode_uncomp_fields ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

Encode uncompressed fields with the corresponding encoding scheme.

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
Returns:
true in case of success, false otherwise
static int header_fields ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const unsigned short  changed_f,
const struct ip_packet *const   ip,
const int  I,
const ip_header_pos_t  ip_hdr_pos,
uint8_t *const   dest,
int  counter 
) [static]

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
     ..... ..... ..... ..... ..... ..... ..... .....

 For outer IP-ID:
     ..... ..... ..... ..... ..... ..... ..... .....
 5  |                  IP-ID                        |  2 octets,
     ..... ..... ..... ..... ..... ..... ..... .....    if I2 = 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
I The I flag of the IP header
ip_hdr_pos The position of the 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
See also:
changed_fields
static int header_flags ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const unsigned short  changed_f,
const struct ip_packet *const   ip,
const int  ip2_or_I2,
uint8_t *const   dest,
int  counter 
) [static]

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 | ip2 |  ip2 = 0 if non-RTP
    +-----+-----+-----+-----+-----+-----+-----+-----+

 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
ip2_or_I2 Whether the ip2 (inner, RTP only) or I2 (outer) flag is set or not
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
static void ip_header_info_free ( struct ip_header_info *const   header_info  )  [static]

Reset the given IP header info.

Parameters:
header_info The IP header info to reset
static bool ip_header_info_new ( struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
const size_t  list_trans_nr,
const size_t  wlsb_window_width,
rohc_trace_callback2_t  trace_cb,
void *const   trace_cb_priv,
const int  profile_id 
) [static]

Initialize the IP header info stored in the context.

Parameters:
header_info The IP header info to initialize
ip The IP header
list_trans_nr The number of uncompressed transmissions for list compression (L)
wlsb_window_width The width of the W-LSB sliding window for IPv4 IP-ID (must be > 0)
trace_cb The function to call for printing traces
trace_cb_priv An optional private context, may be NULL
profile_id The ID of the associated compression profile
Returns:
true if successful, false otherwise
static bool is_field_changed ( const unsigned short  changed_fields,
const unsigned short  check_field 
) [static]

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:
1 if the field changed, 0 if not
See also:
changed_fields
static int rohc_code_dynamic_ip_part ( const struct rohc_comp_ctxt *const   context,
const unsigned int  hdr_pos,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]

Build the dynamic part of one IP header for the IR/IR-DYN packets.

Parameters:
context The compression context
hdr_pos The position of the IP header: 1 for the outer header or 2 for the inner IP header
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, -1 in case of error
static int rohc_code_dynamic_part ( const struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
int  counter 
) [static]

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

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt The rohc-packet-under-build buffer
counter The current position in the rohc-packet-under-build buffer
Returns:
The new position in the rohc-packet-under-build buffer
static int rohc_code_static_ip_part ( const struct rohc_comp_ctxt *const   context,
struct ip_header_info *const   header_info,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]

Build the static part of one IP header for the IR packet.

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
static int rohc_code_static_part ( const struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
int  counter 
) [static]

Build the static part of the IR packet.

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt The rohc-packet-under-build buffer
counter The current position in the rohc-packet-under-build buffer
Returns:
The new position in the rohc-packet-under-build buffer
static int rohc_comp_rfc3095_build_uo1_pkt ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

Build the UO-1 packet for the non-RTP profiles.

The UO-1 packet type 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    |
    +---+---+---+---+---+---+---+---+
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
[out] rohc_pkt The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int rohc_comp_rfc3095_build_uo1id_pkt ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

Build the UO-1-ID packet.

The UO-1-ID packet type 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-ID (5.7.3):

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

 X: X = 0 indicates that no extension is present;
    X = 1 indicates that an extension is present.

 T: T = 0 indicates format UO-1-ID;
    T = 1 indicates format UO-1-TS.
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
[out] rohc_pkt The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int rohc_comp_rfc3095_build_uo1rtp_pkt ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

Build the UO-1 packet for the RTP profiles.

The UO-1 packet type 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 (5.7.3):

      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
 2  | 1   0 |          TS           |
    +===+===+===+===+===+===+===+===+
 4  | M |      SN       |    CRC    |
    +---+---+---+---+---+---+---+---+
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
[out] rohc_pkt The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static int rohc_comp_rfc3095_build_uo1ts_pkt ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len 
) [static]

Build the UO-1-TS 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-1-TS (5.7.3):

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

 T: T = 0 indicates format UO-1-ID;
    T = 1 indicates format UO-1-TS.
Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
[out] rohc_pkt The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
bool rohc_comp_rfc3095_check_profile ( const struct rohc_comp *const   comp,
const struct net_pkt *const   packet 
)

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

Conditions are:

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

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

Parameters:
comp The ROHC compressor
packet The packet to check
Returns:
Whether the IP packet corresponds to the profile:
  • true if the IP packet corresponds to the profile,
  • false if the IP packet does not correspond to the profile
bool rohc_comp_rfc3095_create ( struct rohc_comp_ctxt *const   context,
const rohc_lsb_shift_t  sn_shift,
const struct net_pkt *const   packet 
)

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

Parameters:
context The compression context
sn_shift The shift parameter (p) to use for encoding SN with W-LSB
packet The packet given to initialize the new context
Returns:
bool if successful, false otherwise
void rohc_comp_rfc3095_decide_state ( struct rohc_comp_ctxt *const   context  ) 

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

The three states are:

  • Initialization and Refresh (IR),
  • First Order (FO),
  • Second Order (SO).
Parameters:
context The compression context
void rohc_comp_rfc3095_destroy ( struct rohc_comp_ctxt *const   context  ) 

Destroy the context.

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

Parameters:
context The compression context
static bool rohc_comp_rfc3095_detect_changes ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

Detect changes between packet and context.

Parameters:
context The compression context to compare
uncomp_pkt The uncompressed packet to compare
Returns:
true if changes were successfully detected, false if a problem occurred
int rohc_comp_rfc3095_encode ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len,
rohc_packet_t *const   packet_type,
size_t *const   payload_offset 
)

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

1. parse uncompressed packet (done in rohc_compress4)
2. detect changes between the new uncompressed packet and the context
3. decide new compressor state
4. determine how many bytes are required for every field
5. decide which packet to send
6. code the ROHC header
7. copy the packet payload (done in rohc_compress4)
8. update the context with the new headers

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

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
packet_type OUT: The type of ROHC packet that is created
payload_offset OUT: The offset for the payload in the IP packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
bool rohc_comp_rfc3095_feedback ( struct rohc_comp_ctxt *const   context,
const enum rohc_feedback_type  feedback_type,
const uint8_t *const   packet,
const size_t  packet_len,
const uint8_t *const   feedback_data,
const size_t  feedback_data_len 
)

Update the profile when feedback is received.

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

Parameters:
context The compression context
feedback_type The feedback type
packet The whole feedback packet with CID bits
packet_len The length of the whole feedback packet with CID bits
feedback_data The feedback data without the CID bits
feedback_data_len The length of the feedback data without the CID bits
Returns:
true if the feedback was successfully handled, false if the feedback could not be taken into account
static bool rohc_comp_rfc3095_feedback_2 ( struct rohc_comp_ctxt *const   context,
const uint8_t *const   packet,
const size_t  packet_len,
const uint8_t *const   feedback_data,
const size_t  feedback_data_len 
) [static]

Update the profile when FEEDBACK-2 is received.

Parameters:
context The compression context
packet The whole feedback packet with CID bits
packet_len The length of the whole feedback packet with CID bits
feedback_data The feedback data without the CID bits
feedback_data_len The length of the feedback data without the CID bits
Returns:
true if the feedback was successfully handled, false if the feedback could not be taken into account
static void rohc_comp_rfc3095_feedback_ack ( struct rohc_comp_ctxt *const   context,
const uint32_t  sn_bits,
const size_t  sn_bits_nr,
const bool  sn_not_valid 
) [static]

Perform the required actions after the reception of a positive ACK.

Parameters:
context The compression context that received a positive ACK
sn_bits The LSB bits of the acknowledged SN
sn_bits_nr The number of LSB bits of the acknowledged SN
sn_not_valid Whether the received SN may be considered as valid or not
static void rohc_comp_rfc3095_get_ext3_I_flags ( const struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
const rohc_packet_t  packet_type,
const size_t  nr_ip_id_bits,
const size_t  nr_ip_id_bits2,
ip_header_pos_t *const   innermost_ipv4_non_rnd,
uint8_t *const   I,
uint8_t *const   I2 
) [static]

Determine the values of the I and I2 flags for UO* extension 3.

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
packet_type The type of packet that is being built
nr_ip_id_bits The number of IP-ID bits for the first IP header
nr_ip_id_bits2 The number of IP-ID bits for the second IP header (if any)
[out] innermost_ipv4_non_rnd The position of the innermost IPv4 header with a non-random IP-ID field
[out] I The value of the I flag in UO extension 3, ie. whether the innermost IPv4 header with a non-random IP-ID needs to transmit some IP-ID bits
[out] I2 The value of the I2 flag in UO extension 3, ie. whether the 2nd innermost IPv4 header with a non-random IP-ID needs to transmit some IP-ID bits
bool rohc_comp_rfc3095_is_sn_possible ( const struct rohc_comp_rfc3095_ctxt *const   rfc3095_ctxt,
const size_t  bits_nr,
const size_t  add_bits_nr 
)

Are the given SN field sizes possible?

Parameters:
rfc3095_ctxt The compression context
bits_nr The base number of SN bits
add_bits_nr The additional number of SN bits
Returns:
true if the SN field is usable, false if not
static void rohc_get_innermost_ipv4_non_rnd ( const struct rohc_comp_ctxt *const   context,
ip_header_pos_t *const   pos,
size_t *const   nr_bits,
uint16_t *const   offset 
) [static]

Determine the number of IP-ID bits and the IP-ID offset of the innermost IPv4 header with non-random IP-ID.

Parameters:
context The compression context
pos OUT: The position of the header
nr_bits OUT: the number of IP-ID bits of the found header
offset OUT: the IP-ID offset of the found header
void rohc_get_ipid_bits ( const struct rohc_comp_ctxt *const   context,
size_t *const   nr_innermost_bits,
size_t *const   nr_outermost_bits 
)

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

Parameters:
context The compression context
nr_innermost_bits OUT: the maximum number of IP-ID bits for the innermost IPv4 header
nr_outermost_bits OUT: the maximum number of IP-ID bits for the outermost IP header
static int rtp_header_flags_and_fields ( const struct rohc_comp_ctxt *const   context,
const struct ip_packet *const   ip,
uint8_t *const   dest,
int  counter 
) [static]
static void update_context ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

Update the compression context with the successfully compressed packet.

Parameters:
context The compression context to update
uncomp_pkt The uncompressed packet that updates the context
static void update_context_ip_hdr ( struct ip_header_info *const   ip_flags,
const struct ip_packet *const   ip 
) [static]

Update the IP information with the IP header.

Parameters:
ip_flags The IP context to update
ip The uncompressed IP header that updates the context
Generated on 4 Jul 2018 for ROHC compression/decompression library by  doxygen 1.6.1