mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
416d0a638c
Reviewed-by: Tim Hudson <tjh@openssl.org> Reviewed-by: Tomas Mraz <tomas@openssl.org> (Merged from https://github.com/openssl/openssl/pull/18382)
124 lines
4.1 KiB
C
124 lines
4.1 KiB
C
/*
|
|
* Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
|
|
*
|
|
* Licensed under the Apache License 2.0 (the "License"). You may not use
|
|
* this file except in compliance with the License. You can obtain a copy
|
|
* in the file LICENSE in the source distribution or at
|
|
* https://www.openssl.org/source/license.html
|
|
*/
|
|
|
|
#ifndef OSSL_INTERNAL_QUIC_VLINT_H
|
|
# define OSSL_INTERNAL_QUIC_VLINT_H
|
|
# pragma once
|
|
|
|
#include "internal/e_os.h"
|
|
|
|
/* The smallest value requiring a 1, 2, 4, or 8-byte representation. */
|
|
#define OSSL_QUIC_VLINT_1B_MIN 0
|
|
#define OSSL_QUIC_VLINT_2B_MIN 64
|
|
#define OSSL_QUIC_VLINT_4B_MIN 16384
|
|
#define OSSL_QUIC_VLINT_8B_MIN 1073741824
|
|
|
|
/* The largest value representable in a given number of bytes. */
|
|
#define OSSL_QUIC_VLINT_1B_MAX (OSSL_QUIC_VLINT_2B_MIN - 1)
|
|
#define OSSL_QUIC_VLINT_2B_MAX (OSSL_QUIC_VLINT_4B_MIN - 1)
|
|
#define OSSL_QUIC_VLINT_4B_MAX (OSSL_QUIC_VLINT_8B_MIN - 1)
|
|
#define OSSL_QUIC_VLINT_8B_MAX (((uint64_t)1 << 62) - 1)
|
|
|
|
/* The largest value representable as a variable-length integer. */
|
|
#define OSSL_QUIC_VLINT_MAX OSSL_QUIC_VLINT_8B_MAX
|
|
|
|
/*
|
|
* Returns the number of bytes needed to encode v in the QUIC variable-length
|
|
* integer encoding.
|
|
*
|
|
* Returns 0 if v exceeds OSSL_QUIC_VLINT_MAX.
|
|
*/
|
|
static ossl_unused ossl_inline size_t ossl_quic_vlint_encode_len(uint64_t v)
|
|
{
|
|
if (v < OSSL_QUIC_VLINT_2B_MIN)
|
|
return 1;
|
|
|
|
if (v < OSSL_QUIC_VLINT_4B_MIN)
|
|
return 2;
|
|
|
|
if (v < OSSL_QUIC_VLINT_8B_MIN)
|
|
return 4;
|
|
|
|
if (v <= OSSL_QUIC_VLINT_MAX)
|
|
return 8;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function writes a QUIC varable-length encoded integer to buf.
|
|
* The smallest usable representation is used.
|
|
*
|
|
* It is the caller's responsibility to ensure that the buffer is big enough by
|
|
* calling ossl_quic_vlint_encode_len(v) before calling this function.
|
|
*
|
|
* Precondition: buf is at least ossl_quic_vlint_enc_len(v) bytes in size
|
|
* (unchecked)
|
|
* Precondition: v does not exceed OSSL_QUIC_VLINT_MAX
|
|
* (unchecked)
|
|
*/
|
|
void ossl_quic_vlint_encode(unsigned char *buf, uint64_t v);
|
|
|
|
/*
|
|
* This function writes a QUIC variable-length encoded integer to buf. The
|
|
* specified number of bytes n are used for the encoding, which means that the
|
|
* encoded value may take up more space than necessary.
|
|
*
|
|
* It is the caller's responsibility to ensure that the buffer is of at least n
|
|
* bytes, and that v is representable by a n-byte QUIC variable-length integer.
|
|
* The representable ranges are:
|
|
*
|
|
* 1-byte encoding: [0, 2** 6-1]
|
|
* 2-byte encoding: [0, 2**14-1]
|
|
* 4-byte encoding: [0, 2**30-1]
|
|
* 8-byte encoding: [0, 2**62-1]
|
|
*
|
|
* Precondition: buf is at least n bytes in size (unchecked)
|
|
* Precondition: v does not exceed the representable range
|
|
* (ossl_quic_vlint_encode_len(v) <= n) (unchecked)
|
|
* Precondition: v does not exceed OSSL_QUIC_VLINT_MAX
|
|
* (unchecked)
|
|
*/
|
|
void ossl_quic_vlint_encode_n(unsigned char *buf, uint64_t v, int n);
|
|
|
|
/*
|
|
* Given the first byte of an encoded QUIC variable-length integer, returns
|
|
* the number of bytes comprising the encoded integer, including the first
|
|
* byte.
|
|
*/
|
|
static ossl_unused ossl_inline size_t ossl_quic_vlint_decode_len(uint8_t first_byte)
|
|
{
|
|
return 1U << ((first_byte & 0xC0) >> 6);
|
|
}
|
|
|
|
/*
|
|
* Given a buffer containing an encoded QUIC variable-length integer, returns
|
|
* the decoded value. The buffer must be of at least
|
|
* ossl_quic_vlint_decode_len(buf[0]) bytes in size, and the caller is responsible
|
|
* for checking this.
|
|
*
|
|
* Precondition: buf is at least ossl_quic_vlint_decode_len(buf[0]) bytes in size
|
|
* (unchecked)
|
|
*/
|
|
uint64_t ossl_quic_vlint_decode_unchecked(const unsigned char *buf);
|
|
|
|
/*
|
|
* Given a buffer buf of buf_len bytes in length, attempts to decode an encoded
|
|
* QUIC variable-length integer at the start of the buffer and writes the result
|
|
* to *v. If buf_len is inadequate, suggesting a truncated encoded integer, the
|
|
* function fails and 0 is returned. Otherwise, returns the number of bytes
|
|
* consumed.
|
|
*
|
|
* Precondition: buf is at least buf_len bytes in size
|
|
* Precondition: v (unchecked)
|
|
*/
|
|
int ossl_quic_vlint_decode(const unsigned char *buf, size_t buf_len, uint64_t *v);
|
|
|
|
#endif
|