nuttx/net/utils/net_getrandom.c
Alin Jerpelea 67d02a45eb net: migrate to SPDX identifier
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2024-09-12 01:08:11 +08:00

85 lines
2.6 KiB
C

/****************************************************************************
* net/utils/net_getrandom.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <string.h>
#include <sys/param.h>
#include <sys/random.h>
#include <nuttx/clock.h>
#include <nuttx/hashtable.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: net_getrandom
*
* Description:
* Fill a buffer of arbitrary length with randomness. This function is
* guaranteed to be success.
*
* Input Parameters:
* bytes - Buffer for returned random bytes
* nbytes - Number of bytes requested.
*
****************************************************************************/
void net_getrandom(FAR void *bytes, size_t nbytes)
{
#if defined(CONFIG_DEV_URANDOM) || defined(CONFIG_DEV_RANDOM)
ssize_t ret = getrandom(bytes, nbytes, 0);
if (ret < 0)
{
ret = getrandom(bytes, nbytes, GRND_RANDOM);
}
if (ret == nbytes)
{
return;
}
#endif
/* Fallback to hash of clock_systime_ticks(), minus nbytes to avoid getting
* same tick count when looping more than once.
*/
while (nbytes > 0)
{
uint32_t hash = HASH(clock_systime_ticks() - nbytes, 32);
size_t ncopy = MIN(nbytes, sizeof(hash));
memcpy(bytes, &hash, ncopy);
nbytes -= ncopy;
bytes = (FAR uint8_t *)bytes + ncopy;
}
}