c_tcp_opts_list.c File Reference

Handle the list of TCP options for the TCP compression profile. More...

#include "c_tcp_opts_list.h"
#include "schemes/tcp_ts.h"
#include "schemes/tcp_sack.h"
#include <string.h>

Include dependency graph for c_tcp_opts_list.c:

Data Structures
struct	c_tcp_opt
Defines
#define	TCP_LIST_ITEM_MAP_LEN 16U
Functions
static bool	c_tcp_opt_get_type_len (const uint8_t const opts_data, const size_t opts_len, uint8_t const opt_type, uint8_t *const opt_len)
	Get the type and length of the next TCP option.
static bool	c_tcp_opt_changed (const struct c_tcp_opts_ctxt const opts_ctxt, const uint8_t opt_idx, const uint8_t const pkt_opt, const size_t pkt_opt_len)
	Does the TCP option changed since last packets?
static void	c_tcp_opt_record (struct c_tcp_opts_ctxt const opts_ctxt, const uint8_t opt_idx, const uint8_t const pkt_opt, const size_t pkt_opt_len)
	Record the TCP option in context.
static void	c_tcp_opt_trace (const struct rohc_comp_ctxt const context, const uint8_t opt_type, const uint8_t const opt_data, const size_t opt_len)
	Print a trace for the given TCP option.
static uint8_t	c_tcp_get_opt_index (const struct rohc_comp_ctxt const context, struct c_tcp_opts_ctxt const opts_ctxt, const uint8_t opt_type, const bool indexes_in_use[MAX_TCP_OPTION_INDEX+1])
	Determine the index of the TCP option.
static int	c_tcp_opt_compute_ps (const uint8_t idx_max)
	Determine PS for the compressed list of TCP options.
static size_t	c_tcp_opt_compute_xi_len (const int ps, const size_t m)
	Determine the length of XI indexes for the list of TCP options.
static size_t	c_tcp_opt_write_xi (const struct rohc_comp_ctxt const context, uint8_t const comp_opts, const int ps, const size_t opt_pos, const uint8_t opt_idx, const bool item_needed)
	Write the XI field for a TCP option.
bool	c_tcp_is_list_item_needed (const struct rohc_comp_ctxt const context, const bool is_dynamic_chain, const uint8_t opt_idx, const uint8_t opt_type, const uint8_t opt_len, const uint8_t const opt, const struct c_tcp_opts_ctxt *const opts_ctxt)
	Shall the list item be transmitted or not?
static int	c_tcp_build_nop_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP NOP option.
static int	c_tcp_build_eol_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP EOL option.
static int	c_tcp_build_mss_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP MSS option.
static int	c_tcp_build_ws_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP WS option.
static int	c_tcp_build_ts_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP TS option.
static int	c_tcp_build_sack_perm_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP SACK Permitted option.
static int	c_tcp_build_sack_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP SACK option.
static int	c_tcp_build_generic_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint8_t const uncomp_opt, const uint8_t uncomp_opt_len, uint8_t const comp_opt, const size_t comp_opt_max_len)
	Build the list item for the TCP generic option.
bool	rohc_comp_tcp_are_options_acceptable (const struct rohc_comp const comp, const uint8_t const opts, const size_t data_offset)
	Whether TCP options are acceptable for TCP profile or not.
bool	tcp_detect_options_changes (struct rohc_comp_ctxt const context, const struct tcphdr const tcp, struct c_tcp_opts_ctxt const opts_ctxt, size_t const opts_len)
	Parse the uncompressed TCP options for changes.
int	c_tcp_code_tcp_opts_list_item (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint16_t msn, const bool is_dynamic_chain, struct c_tcp_opts_ctxt const opts_ctxt, uint8_t const comp_opts, const size_t comp_opts_max_len)
	Build the list of TCP options items.
int	c_tcp_code_tcp_opts_irreg (const struct rohc_comp_ctxt const context, const struct tcphdr const tcp, const uint16_t msn, struct c_tcp_opts_ctxt const opts_ctxt, uint8_t const comp_opts, const size_t comp_opts_max_len)
	Build the list of TCP options for the irregular chain.
Variables
static struct c_tcp_opt	c_tcp_opts [MAX_TCP_OPTION_INDEX+1]
static int	c_tcp_type2index [TCP_LIST_ITEM_MAP_LEN]
	Table of TCP option index, from option Id.

Detailed Description

Handle the list of TCP options for the TCP compression profile.

Author:: FWX <rohc_team@dialine.fr>; Didier Barvaux <didier@barvaux.org>; Didier Barvaux <didier.barvaux@toulouse.viveris.com>

Define Documentation

#define TCP_LIST_ITEM_MAP_LEN 16U

The length of the table mapping for TCP options

Function Documentation

static int c_tcp_build_eol_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP EOL option.


   pad_len =:= compressed_value(8, nbits-8) [ 8 ];

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_generic_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP generic option.


   type          =:= irregular(8)      [ 8 ];
   option_static =:= one_bit_choice    [ 1 ];
   length_lsb    =:= irregular(7)      [ 7 ];
   contents      =:=
     irregular(length_lsb.UVALUE*8-16) [ length_lsb.UVALUE*8-16 ];

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_mss_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP MSS option.


   mss =:= irregular(16) [ 16 ];

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_nop_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP NOP option.

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_sack_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP SACK option.

See RFC4996 page 67.

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_sack_perm_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP SACK Permitted option.

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_ts_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP TS option.


   tsval  =:= irregular(32) [ 32 ];
   tsecho =:= irregular(32) [ 32 ];

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

static int c_tcp_build_ws_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint8_t *const	uncomp_opt,
		const uint8_t	uncomp_opt_len,
		uint8_t *const	comp_opt,
		const size_t	comp_opt_max_len
	)			`[static]`

Build the list item for the TCP WS option.


   wscale =:= irregular(8) [ 8 ];

Parameters:

	context	The compression context
	tcp	The TCP header
	uncomp_opt	The uncompressed TCP option to compress
	uncomp_opt_len	The length of the uncompressed TCP option to compress
`[out]`	comp_opt	The compressed TCP option
	comp_opt_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP option in case of success, -1 in case of failure

int c_tcp_code_tcp_opts_irreg	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint16_t	msn,
		struct c_tcp_opts_ctxt *const	opts_ctxt,
		uint8_t *const	comp_opts,
		const size_t	comp_opts_max_len
	)

Build the list of TCP options for the irregular chain.

All the CO packets contains an irregular chain.

Parameters:

	context	The compression context
	tcp	The TCP header
	msn	The Master Sequence Number (MSN) of the packet to compress
`[in,out]`	opts_ctxt	The compression context for TCP options
`[out]`	comp_opts	The compressed TCP options
	comp_opts_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP options in case of success, -1 in case of failure

Todo:: TODO: defines 'options profiles' the same way as for decompressor

int c_tcp_code_tcp_opts_list_item	(	const struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		const uint16_t	msn,
		const bool	is_dynamic_chain,
		struct c_tcp_opts_ctxt *const	opts_ctxt,
		uint8_t *const	comp_opts,
		const size_t	comp_opts_max_len
	)

Build the list of TCP options items.

The list of TCP options is used in the dynamic chain of the IR and IR-DYN packets, but also at the end of the rnd_8, seq_8, and co_common packets.

Parameters:

	context	The compression context
	tcp	The TCP header
	msn	The Master Sequence Number (MSN) of the packet to compress
	is_dynamic_chain	Whether the list of items is for the dynamic chain or not
`[in,out]`	opts_ctxt	The compression context for TCP options
`[out]`	comp_opts	The compressed TCP options
	comp_opts_max_len	The max remaining length in the ROHC buffer

Returns:: The length (in bytes) of compressed TCP options in case of success, -1 in case of failure

static uint8_t c_tcp_get_opt_index	(	const struct rohc_comp_ctxt *const	context,
		struct c_tcp_opts_ctxt *const	opts_ctxt,
		const uint8_t	opt_type,
		const bool	indexes_in_use[MAX_TCP_OPTION_INDEX+1]
	)			`[static]`

Determine the index of the TCP option.

Parameters:

	context	The compression context
`[in,out]`	opts_ctxt	The compression context for TCP options
	opt_type	The type of the option
	indexes_in_use	What indexes are used by the current packet?

Returns:: true if the TCP options were successfully parsed and can be compressed, false otherwise

bool c_tcp_is_list_item_needed	(	const struct rohc_comp_ctxt *const	context,
		const bool	is_dynamic_chain,
		const uint8_t	opt_idx,
		const uint8_t	opt_type,
		const uint8_t	opt_len,
		const uint8_t *const	opt,
		const struct c_tcp_opts_ctxt *const	opts_ctxt
	)

Shall the list item be transmitted or not?

Parameters:

	context	The compression context
	is_dynamic_chain	Whether the list of items is for the dynamic chain or not
	opt_idx	The compression index of the TCP option to compress
	opt_type	The type of the TCP option to compress
	opt_len	The length of the TCP option to compress
	opt	The TCP option to compress
	opts_ctxt	The compression context for TCP options

Returns:: true if the list item shall be transmitted, false if it shall not

static bool c_tcp_opt_changed	(	const struct c_tcp_opts_ctxt *const	opts_ctxt,
		const uint8_t	opt_idx,
		const uint8_t *const	pkt_opt,
		const size_t	pkt_opt_len
	)			`[static]`

Does the TCP option changed since last packets?

The TCP option changed if the packet TCP option do not match the TCP option that was recorded in the compression context.

Parameters:

	opts_ctxt	The compression context of the TCP options
	opt_idx	The index of the TCP option in the TCP compression context
	pkt_opt	The TCP option as found in the TCP packet
	pkt_opt_len	The length of the TCP option as found in the TCP packet

Returns:: true if the TCP option changed, false if it doesn't

static int c_tcp_opt_compute_ps ( const uint8_t idx_max ) [static]

Determine PS for the compressed list of TCP options.

According to RFC6846, §6.3.3, PS indicates size of XI fields:

PS = 0 indicates 4-bit XI fields;
PS = 1 indicates 8-bit XI fields.

The rational to choose is: use 4-bit XI fields if the largest option index may fit in 4 bits, otherwise fallback on the 8-bit XI fields

Parameters:

idx_max

The largest option index used in the compressed packet

Returns:: The PS value

static size_t c_tcp_opt_compute_xi_len	(	const int	ps,
		const size_t	m
	)			`[static]`

Determine the length of XI indexes for the list of TCP options.

The length of the XI indexes depends on the type of XI fields we use. According to RFC6846, §6.3.3, PS indicates size of XI fields:

PS = 0 indicates 4-bit XI fields;
PS = 1 indicates 8-bit XI fields.

The computed XI length includes the first byte that contain the reserved bits, the PS flag and the number of XI indexes (m).

Parameters:

	ps	The PS value
	m	The number of elements in the list

Returns:: The length (in bytes) of the XI indexes

static bool c_tcp_opt_get_type_len	(	const uint8_t *const	opts_data,
		const size_t	opts_len,
		uint8_t *const	opt_type,
		uint8_t *const	opt_len
	)			`[static]`

Get the type and length of the next TCP option.

Parameters:

	opts_data	The remaining data in the TCP options
	opts_len	The length of the remaining data in the TCP options
`[out]`	opt_type	The type of the TCP option
`[out]`	opt_len	The length (in bytes) of the TCP option

Returns:: true if one well-formed TCP option was found, false if the TCP option is malformed

static void c_tcp_opt_record	(	struct c_tcp_opts_ctxt *const	opts_ctxt,
		const uint8_t	opt_idx,
		const uint8_t *const	pkt_opt,
		const size_t	pkt_opt_len
	)			`[static]`

Record the TCP option in context.

Parameters:

`[out]`	opts_ctxt	The TCP compression context
	opt_idx	The index of the TCP option in the TCP compression context
	pkt_opt	The TCP option as found in the TCP packet
	pkt_opt_len	The length of the TCP option as found in the TCP packet

static void c_tcp_opt_trace	(	const struct rohc_comp_ctxt *const	context,
		const uint8_t	opt_type,
		const uint8_t *const	opt_data,
		const size_t	opt_len
	)			`[static]`

Print a trace for the given TCP option.

Parameters:

	context	The compression context
	opt_type	The type of the TCP option to print a trace for
	opt_data	The data of the TCP option to print a trace for
	opt_len	The length (in bytes) of the TCP option to print a trace for

static size_t c_tcp_opt_write_xi	(	const struct rohc_comp_ctxt *const	context,
		uint8_t *const	comp_opts,
		const int	ps,
		const size_t	opt_pos,
		const uint8_t	opt_idx,
		const bool	item_needed
	)			`[static]`

Write the XI field for a TCP option.

The room available in comp_opts shall have been checked before calling this function.

Parameters:

	context	The compression context
`[in,out]`	comp_opts	The compressed options
	ps	0 to use 4-bit XI fields, or 1 to use 8-bit XI fields
	opt_pos	The position of the TCP option in the list (opt_pos starts at 0)
	opt_idx	The index of the TCP option
	item_needed	Whether the TCP option requires its related item to be present or not

Returns:: The number of bytes completed

bool rohc_comp_tcp_are_options_acceptable	(	const struct rohc_comp *const	comp,
		const uint8_t *const	opts,
		const size_t	data_offset
	)

Whether TCP options are acceptable for TCP profile or not.

TCP options are acceptable for the TCP profile if:

the last TCP option is not truncated,
well-known TCP options got the expected length (see below),
no more than ROHC_TCP_OPTS_MAX options are present,
each TCP options is present only once (except EOL and NOP).

The following well-known TCP options shall have expected lengthes:

MSS shall be TCP_OLEN_MSS long,
WS shall be TCP_OLEN_WS long,
SACK Permitted shall be TCP_OLEN_SACK_PERM long,
SACK shall be 2 + N * 8 with N in range [1, 4]
TS shall be TCP_OLEN_TS long.

Parameters:

	comp	The ROHC compressor
	opts	The beginning of the TCP options
	data_offset	The length (in 32-bit words) of the full TCP header

Returns:: true if the TCP options are acceptable, false if they are not

See also:: ROHC_TCP_OPTS_MAX

bool tcp_detect_options_changes	(	struct rohc_comp_ctxt *const	context,
		const struct tcphdr *const	tcp,
		struct c_tcp_opts_ctxt *const	opts_ctxt,
		size_t *const	opts_len
	)

Parse the uncompressed TCP options for changes.

Parameters:

	context	The compression context
	tcp	The TCP header
`[in,out]`	opts_ctxt	The compression context for TCP options
`[out]`	opts_len	The length (in bytes) of the TCP options

Returns:: true if the TCP options were successfully parsed and can be compressed, false otherwise

Variable Documentation

struct c_tcp_opt c_tcp_opts[MAX_TCP_OPTION_INDEX+1] [static]

int c_tcp_type2index[TCP_LIST_ITEM_MAP_LEN] [static]

Initial value:

{
        TCP_INDEX_EOL,             
        TCP_INDEX_NOP,             
        TCP_INDEX_MSS,             
        TCP_INDEX_WS,              
        TCP_INDEX_SACK_PERM,       
        TCP_INDEX_SACK,            
        -1,                        
        -1,                        
        TCP_INDEX_TS,              
        -1,                        
        -1,                        
        -1,                        
        -1,                        
        -1,                        
        -1,                        
        -1                         
}

Table of TCP option index, from option Id.

See RFC4996 §6.3.4 Return item index of TCP option

c_tcp_opts_list.c File Reference

Data Structures

Defines

Functions

Variables

Detailed Description

Define Documentation

Function Documentation

Variable Documentation