Overview

Parse or pack a generic PDU or PDU block.

#include "lwpa_pdu.h"

Modules
	lwpa_rootlayerpdu
	Parse or pack a Root Layer PDU block.

Data Structures
struct	LwpaPdu
	Holds state data used when parsing multiple PDUs in a PDU block. More...

struct	LwpaPduConstraints
	Contains specific PDU info used by the generic helper parse_pdu(). More...

Macros
#define	pdu_length(pdu_buf)
	Get the length from the Length field of a PDU. More...

#define	pdu_pack_normal_len(pdu_buf, length)
	Fill in the Length field of a PDU which has a length less than 4096. More...

#define	pdu_pack_ext_len(pdu_buf, length)
	Fill in the Length field of a PDU which has a length 4096 or greater. More...

#define	PDU_INIT
	Default LwpaPdu initializer values; must be used to intialize a struct pdu when parsing the first PDU in a block. More...

#define	init_pdu(pduptr)
	An alternative to PDU_INIT which can be used on an existing LwpaPdu to re-initialize its values. More...

Typedefs
typedef struct LwpaPdu	LwpaPdu
	Holds state data used when parsing multiple PDUs in a PDU block.

typedef struct LwpaPduConstraints	LwpaPduConstraints
	Contains specific PDU info used by the generic helper parse_pdu().

Functions
bool	parse_pdu (const uint8_t buf, size_t buflen, const LwpaPduConstraints constraints, LwpaPdu *pdu)
	Parse a generic PDU. More...

Get the inheritance and length bits in a PDU Flags & Length segment.
The first byte of each PDU contains a flags field which indicates the inheritance properties of that PDU. For more information, see ANSI E1.17, ACN Architecture, s. 2.4.
#define	l_flag_set(flags_byte) ((bool)(flags_byte & 0x80))
	Determine whether the L flag is set in a PDU flags field. More...

#define	v_flag_set(flags_byte) ((bool)(flags_byte & 0x40))
	Determine whether the V flag is set in a PDU flags field. More...

#define	h_flag_set(flags_byte) ((bool)(flags_byte & 0x20))
	Determine whether the H flag is set in a PDU flags field. More...

#define	d_flag_set(flags_byte) ((bool)(flags_byte & 0x10))
	Determine whether the D flag is set in a PDU flags field. More...

Set the inheritance and length bits in a PDU Flags & Length segment.
The first byte of each PDU contains a flags field which indicates the inheritance properties of that PDU. For more information, see ANSI E1.17, ACN Architecture, s. 2.4.
#define	set_l_flag(flags_byte) (flags_byte \|= 0x80)
	Set the L flag in a PDU flags field. More...

#define	set_v_flag(flags_byte) (flags_byte \|= 0x40)
	Set the V flag in a PDU flags field. More...

#define	set_h_flag(flags_byte) (flags_byte \|= 0x20)
	Set the H flag in a PDU flags field. More...

#define	set_d_flag(flags_byte) (flags_byte \|= 0x10)
	Set the D flag in a PDU flags field. More...

Macro Definition Documentation

◆ d_flag_set

#define d_flag_set ( flags_byte ) ((bool)(flags_byte & 0x10))

Determine whether the D flag is set in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

Returns: true (the D flag is set) or false (the D flag is not set).

◆ h_flag_set

#define h_flag_set ( flags_byte ) ((bool)(flags_byte & 0x20))

Determine whether the H flag is set in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

Returns: true (the H flag is set) or false (the H flag is not set).

◆ init_pdu

#define init_pdu ( pduptr )

Value:

  do                           \
  {                            \
    (pduptr)->pvector = NULL;  \
    (pduptr)->pheader = NULL;  \
    (pduptr)->pdata = NULL;    \
    (pduptr)->datalen = 0;     \
    (pduptr)->pnextpdu = NULL; \
  } while (0)

An alternative to PDU_INIT which can be used on an existing LwpaPdu to re-initialize its values.

Parameters

pduptr Pointer to LwpaPdu to initialize.

◆ l_flag_set

#define l_flag_set ( flags_byte ) ((bool)(flags_byte & 0x80))

Determine whether the L flag is set in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

Returns: true (the L flag is set) or false (the L flags is not set).

◆ PDU_INIT

#define PDU_INIT

Value:

  {                           \
    NULL, NULL, NULL, 0, NULL \
  }

Default LwpaPdu initializer values; must be used to intialize a struct pdu when parsing the first PDU in a block.

◆ pdu_length

#define pdu_length ( pdu_buf )

Value:

((uint32_t)(l_flag_set(pdu_buf[0]) ? (((pdu_buf[0] & 0x0f) << 16) | (pdu_buf[1] << 8) | pdu_buf[2]) \

: (((pdu_buf[0] & 0x0f) << 8) | pdu_buf[1])))

l_flag_set

#define l_flag_set(flags_byte)

Determine whether the L flag is set in a PDU flags field.

Definition: lwpa_pdu.h:47

Get the length from the Length field of a PDU.

Parameters

pdu_buf Pointer to the start of the PDU buffer.

Returns: The length of the PDU.

◆ pdu_pack_ext_len

#define pdu_pack_ext_len	(	pdu_buf,
		length
	)

Value:

  do                                                                    \
  {                                                                     \
    (pdu_buf)[0] = (((pdu_buf)[0] & 0xf0) | (((length) >> 16) & 0x0f)); \
    (pdu_buf)[1] = (((length) >> 8) & 0xff);                            \
    (pdu_buf)[2] = (length)&0xff;                                       \
  } while (0)

Fill in the Length field of a PDU which has a length 4096 or greater.

The L flag of this PDU must be set to 1.

Parameters

pdu_buf	Pointer to the start of the PDU buffer.
length	Length of this PDU.

◆ pdu_pack_normal_len

#define pdu_pack_normal_len	(	pdu_buf,
		length
	)

Value:

  do                                                                   \
  {                                                                    \
    (pdu_buf)[0] = (((pdu_buf)[0] & 0xf0) | (((length) >> 8) & 0x0f)); \
    (pdu_buf)[1] = (length)&0xff;                                      \
  } while (0)

Fill in the Length field of a PDU which has a length less than 4096.

The L flag of this PDU must be set to 0.

Parameters

pdu_buf	Pointer to the start of the PDU buffer.
length	Length of this PDU.

◆ set_d_flag

#define set_d_flag ( flags_byte ) (flags_byte |= 0x10)

Set the D flag in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

◆ set_h_flag

#define set_h_flag ( flags_byte ) (flags_byte |= 0x20)

Set the H flag in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

◆ set_l_flag

#define set_l_flag ( flags_byte ) (flags_byte |= 0x80)

Set the L flag in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

◆ set_v_flag

#define set_v_flag ( flags_byte ) (flags_byte |= 0x40)

Set the V flag in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

◆ v_flag_set

#define v_flag_set ( flags_byte ) ((bool)(flags_byte & 0x40))

Determine whether the V flag is set in a PDU flags field.

Parameters

flags_byte The first byte of the PDU.

Returns: true (the V flag is set) or false (the V flag is not set).

Function Documentation

◆ parse_pdu()

bool parse_pdu	(	const uint8_t *	buf,
		size_t	buflen,
		const LwpaPduConstraints *	constraints,
		LwpaPdu *	pdu
	)

Parse a generic PDU.

A function to parse a generic PDU. The specific PDU info needed for parsing is contained in a struct pdu_constraints. Uses LwpaPdu to maintain state across multiple PDUs in a block.

Parameters

[in]	buf	Byte buffer containing a PDU.
[in]	buflen	Size in bytes of buf.
[in]	constraints	Specific information about the PDU being parsed
[in,out]	pdu	PDU data from the last PDU in the block. The data is used and then replaced with data from this PDU.

Returns: true (PDU was parsed successfully) or false (parse error or no more PDUs in the block).

Overview

Modules

Data Structures

Macros

Typedefs

Functions

Get the inheritance and length bits in a PDU Flags & Length segment.

Set the inheritance and length bits in a PDU Flags & Length segment.

Macro Definition Documentation

◆ d_flag_set

◆ h_flag_set

◆ init_pdu

◆ l_flag_set

◆ PDU_INIT

◆ pdu_length

◆ pdu_pack_ext_len

◆ pdu_pack_normal_len

◆ set_d_flag

◆ set_h_flag

◆ set_l_flag

◆ set_v_flag

◆ v_flag_set

Function Documentation

◆ parse_pdu()