t1_block.cpp File Reference

#include "mod_gpg/openpgp/t1/t1_block.h"
#include <string.h>

Go to the source code of this file.

Functions
uint8_t	t1_lrc (const uint8_t *buf, size_t len)
	Compute the longitudinal redundancy check (LRC) of a buffer.
uint16_t	t1_crc (const uint8_t *buf, size_t len)
	Compute the ISO/IEC 13239 CRC-16 of a buffer (polynomial 0x1021, initial value 0xFFFF, no final XOR, MSB first). Used as the alternative EDC when CRC is negotiated.
static t1_status_t	append_edc (uint8_t *out, size_t prologue_and_inf_len, bool use_crc, size_t out_cap, size_t *out_len)
t1_status_t	t1_block_encode_i (uint8_t nad, uint8_t ns, bool more, const uint8_t *inf, uint8_t inf_len, bool use_crc, uint8_t *out, size_t out_cap, size_t *out_len)
	Encode an I-block.
t1_status_t	t1_block_encode_r (uint8_t nad, uint8_t nr, t1_r_error_t err, bool use_crc, uint8_t *out, size_t out_cap, size_t *out_len)
	Encode an R-block.
t1_status_t	t1_block_encode_s (uint8_t nad, t1_s_subtype_t subtype, const uint8_t *inf, uint8_t inf_len, bool use_crc, uint8_t *out, size_t out_cap, size_t *out_len)
	Encode an S-block.
t1_status_t	t1_block_decode (const uint8_t *buf, size_t buf_len, bool use_crc, t1_block_t *out)
	Decode a T=1 block.

Function Documentation

append_edc()

t1_status_t append_edc ( uint8_t * out, size_t prologue_and_inf_len, bool use_crc, size_t out_cap, size_t * out_len )

static

Definition at line 58 of file t1_block.cpp.

References t1_crc(), T1_ERR_OUT_BUF, t1_lrc(), and T1_OK.

Referenced by t1_block_encode_i(), t1_block_encode_r(), and t1_block_encode_s().

t1_block_decode()

t1_status_t t1_block_decode	(	const uint8_t *	buf,
		size_t	buf_len,
		bool	use_crc,
		t1_block_t *	out )

Decode a T=1 block.

The decoder validates LEN, EDC, and PCB encoding rules. Reserved bits in I- and R-blocks must be zero; otherwise T1_ERR_PCB is returned.

Parameters

buf	Input bytes.
buf_len	Number of bytes available.
use_crc	If true, expect 2-byte CRC; otherwise LRC.
out	Decoded block (INF pointer aliases into buf).

Definition at line 147 of file t1_block.cpp.

References t1_block_t::edc_ok, t1_block_t::i_more, t1_block_t::i_ns, t1_block_t::inf, t1_block_t::inf_len, t1_block_t::kind, t1_block_t::nad, t1_block_t::pcb, t1_block_t::r_err, t1_block_t::r_nr, t1_block_t::s_subtype, T1_BLOCK_I, T1_BLOCK_R, T1_BLOCK_S, t1_crc(), T1_ERR_LEN, T1_ERR_NULL, T1_ERR_PCB, T1_ERR_SHORT, T1_LEN_RESERVED, t1_lrc(), T1_OK, and t1_block_t::use_crc.

t1_block_encode_i()

t1_status_t t1_block_encode_i	(	uint8_t	nad,
		uint8_t	ns,
		bool	more,
		const uint8_t *	inf,
		uint8_t	inf_len,
		bool	use_crc,
		uint8_t *	out,
		size_t	out_cap,
		size_t *	out_len )

Encode an I-block.

Parameters

nad	Node address.
ns	Sequence number (0 or 1).
more	More-data flag (chaining).
inf	Information field payload (may be NULL when inf_len == 0).
inf_len	Payload length (<= T1_INF_MAX).
use_crc	Use 2-byte CRC instead of LRC.
out	Output buffer (caller-allocated, at least 4 + inf_len + (use_crc ? 1 : 0) bytes).
out_cap	Output capacity in bytes.
out_len	Receives total bytes written.

Definition at line 75 of file t1_block.cpp.

References append_edc(), T1_ERR_INF_TOO_BIG, T1_ERR_NULL, T1_ERR_OUT_BUF, T1_ERR_PCB, and T1_INF_MAX.

Referenced by t1_state_next_outbound().

t1_block_encode_r()

t1_status_t t1_block_encode_r	(	uint8_t	nad,
		uint8_t	nr,
		t1_r_error_t	err,
		bool	use_crc,
		uint8_t *	out,
		size_t	out_cap,
		size_t *	out_len )

Encode an R-block.

Parameters

nad	Node address.
nr	Expected sequence number (0 or 1).
err	Error indicator.
use_crc	EDC algorithm select.
out	Output buffer.
out_cap	Output buffer capacity.
out_len	Receives bytes written.

Definition at line 103 of file t1_block.cpp.

References append_edc(), T1_ERR_NULL, T1_ERR_OUT_BUF, and T1_ERR_PCB.

Referenced by encode_rblock().

t1_block_encode_s()

t1_status_t t1_block_encode_s	(	uint8_t	nad,
		t1_s_subtype_t	subtype,
		const uint8_t *	inf,
		uint8_t	inf_len,
		bool	use_crc,
		uint8_t *	out,
		size_t	out_cap,
		size_t *	out_len )

Encode an S-block.

Parameters

nad	Node address.
subtype	S-block subtype (request or response).
inf	Optional info payload (e.g. IFS new value).
inf_len	Length of the info payload (0..254).
use_crc	EDC algorithm select.
out	Output buffer.
out_cap	Output buffer capacity.
out_len	Receives bytes written.

Definition at line 123 of file t1_block.cpp.

References append_edc(), T1_ERR_INF_TOO_BIG, T1_ERR_NULL, T1_ERR_OUT_BUF, T1_ERR_PCB, and T1_INF_MAX.

Referenced by encode_sblock_response().

t1_crc()

uint16_t t1_crc	(	const uint8_t *	buf,
		size_t	len )

Compute the ISO/IEC 13239 CRC-16 of a buffer (polynomial 0x1021, initial value 0xFFFF, no final XOR, MSB first). Used as the alternative EDC when CRC is negotiated.

Definition at line 41 of file t1_block.cpp.

Referenced by append_edc(), and t1_block_decode().

t1_lrc()

uint8_t t1_lrc	(	const uint8_t *	buf,
		size_t	len )

Compute the longitudinal redundancy check (LRC) of a buffer.

LRC is the bytewise XOR of all bytes in buf. Used as the default EDC byte when the T=1 protocol parameters do not select CRC.

Parameters

buf	Buffer pointer.
len	Number of bytes to fold into the LRC.

Returns

XOR of all bytes.

Definition at line 33 of file t1_block.cpp.

Referenced by append_edc(), and t1_block_decode().