c_esp.c File Reference

ROHC ESP compression profile. More...

#include "rohc_comp_rfc3095.h"
#include "c_ip.h"
#include "rohc_traces_internal.h"
#include "crc.h"
#include "protocols/esp.h"
#include "rohc_utils.h"
#include <stdbool.h>
#include <string.h>
#include <assert.h>
Include dependency graph for c_esp.c:

Data Structures

struct  sc_esp_context
 Define the ESP part of the profile decompression context. More...

Functions

static bool c_esp_create (struct rohc_comp_ctxt *const context, const struct net_pkt *const packet)
 Create a new ESP context and initialize it thanks to the given IP/ESP packet.
static bool c_esp_check_profile (const struct rohc_comp *const comp, const struct net_pkt *const packet)
 Check if the given packet corresponds to the ESP profile.
static bool c_esp_check_context (const struct rohc_comp_ctxt *const context, const struct net_pkt *const packet)
 Check if the IP/ESP packet belongs to the context.
static int c_esp_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/ESP packet according to a pattern decided by several different factors.
static uint32_t c_esp_get_next_sn (const struct rohc_comp_ctxt *const context, const struct net_pkt *const uncomp_pkt)
 Determine the SN value for the next packet.
static size_t esp_code_static_esp_part (const struct rohc_comp_ctxt *const context, const uint8_t *const next_header, uint8_t *const dest, const size_t counter)
 Build the static part of the ESP header.
static size_t esp_code_dynamic_esp_part (const struct rohc_comp_ctxt *const context, const uint8_t *const next_header, uint8_t *const dest, const size_t counter)
 Build the dynamic part of the ESP header.

Variables

struct rohc_comp_profile c_esp_profile
 Define the compression part of the ESP profile as described in the RFC 3095.

Detailed Description

ROHC ESP compression profile.

Author:
FWX <rohc_team@dialine.fr>
Didier Barvaux <didier@barvaux.org>

Function Documentation

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

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

Conditions are:

  • the number of IP headers must be the same as in context
  • IP version of the two IP headers must be the same as in context
  • IP packets must not be fragmented
  • the source and destination addresses of the two IP headers must match the ones in the context
  • the transport protocol must be ESP
  • the security parameters index of the ESP header must match the one in the context
  • IPv6 only: the Flow Label of the two IP headers must match the ones the context

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

Parameters:
context The compression context
packet The IP/UDP packet to check
Returns:
true if the packet belongs to the context, false if it does not belong to the context
static bool c_esp_check_profile ( const struct rohc_comp *const   comp,
const struct net_pkt *const   packet 
) [static]

Check if the given packet corresponds to the ESP profile.

Conditions are:

  • the transport protocol is ESP
  • the version of the outer IP header is 4 or 6
  • the outer IP header is not an IP fragment
  • if there are at least 2 IP headers, the version of the inner IP header is 4 or 6
  • if there are at least 2 IP headers, the inner IP header is not an IP fragment
See also:
rohc_comp_rfc3095_check_profile

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

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

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

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

Parameters:
context The compression context
packet The IP/ESP packet given to initialize the new context
Returns:
true if successful, false otherwise
static int c_esp_encode ( struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt,
uint8_t *const   rohc_pkt,
const size_t  rohc_pkt_max_len,
rohc_packet_t *const   packet_type,
size_t *const   payload_offset 
) [static]

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

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
rohc_pkt OUT: The ROHC packet
rohc_pkt_max_len The maximum length of the ROHC packet
packet_type OUT: The type of ROHC packet that is created
payload_offset OUT: The offset for the payload in the IP packet
Returns:
The length of the ROHC packet if successful, -1 otherwise
static uint32_t c_esp_get_next_sn ( const struct rohc_comp_ctxt *const   context,
const struct net_pkt *const   uncomp_pkt 
) [static]

Determine the SN value for the next packet.

Profile SN is the ESP SN.

Parameters:
context The compression context
uncomp_pkt The uncompressed packet to encode
Returns:
The SN
static size_t esp_code_dynamic_esp_part ( const struct rohc_comp_ctxt *const   context,
const uint8_t *const   next_header,
uint8_t *const   dest,
const size_t  counter 
) [static]

Build the dynamic part of the ESP header. 


 Dynamic part of ESP header (5.7.7.7):

    +---+---+---+---+---+---+---+---+
 1  /       Sequence Number         /   4 octets
    +---+---+---+---+---+---+---+---+
Parameters:
context The compression context
next_header The ESP header
dest The rohc-packet-under-build buffer
counter The current position in the rohc-packet-under-build buffer
Returns:
The new position in the rohc-packet-under-build buffer
static size_t esp_code_static_esp_part ( const struct rohc_comp_ctxt *const   context,
const uint8_t *const   next_header,
uint8_t *const   dest,
const size_t  counter 
) [static]

Build the static part of the ESP header. 


 Static part of ESP header (5.7.7.7):

    +---+---+---+---+---+---+---+---+
 1  /              SPI              /   4 octets
    +---+---+---+---+---+---+---+---+

 SPI = Security Parameters Index
Parameters:
context The compression context
next_header The ESP 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

Variable Documentation

struct rohc_comp_profile c_esp_profile
Initial value:
{
        .id             = ROHC_PROFILE_ESP, 
        .protocol       = ROHC_IPPROTO_ESP, 
        .create         = c_esp_create,     
        .destroy        = rohc_comp_rfc3095_destroy,
        .check_profile  = c_esp_check_profile,
        .check_context  = c_esp_check_context,
        .encode         = c_esp_encode,
        .reinit_context = rohc_comp_reinit_context,
        .feedback       = rohc_comp_rfc3095_feedback,
}

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

Generated on 4 Jul 2018 for ROHC compression/decompression library by  doxygen 1.6.1