/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2020 Alexander V. Chernikov
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include "opt_inet.h"
#include "opt_route.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <net/route/nhop_utils.h>
#define BLOCK_ITEMS (8 * sizeof(u_long)) /* Number of items for ffsl() */
#define _BLOCKS_TO_SZ(_blocks) ((size_t)(_blocks) * sizeof(u_long))
#define _BLOCKS_TO_ITEMS(_blocks) ((uint32_t)(_blocks) * BLOCK_ITEMS)
#define _ITEMS_TO_BLOCKS(_items) ((_items) / BLOCK_ITEMS)
static void _bitmask_init_idx(void *index, uint32_t items);
void
bitmask_init(struct bitmask_head *bh, void *idx, uint32_t num_items)
{
if (idx != NULL)
_bitmask_init_idx(idx, num_items);
memset(bh, 0, sizeof(struct bitmask_head));
bh->blocks = _ITEMS_TO_BLOCKS(num_items);
bh->idx = (u_long *)idx;
}
uint32_t
bitmask_get_resize_items(const struct bitmask_head *bh)
{
if ((bh->items_count * 2 > _BLOCKS_TO_ITEMS(bh->blocks)) && bh->items_count < 65536)
return (_BLOCKS_TO_ITEMS(bh->blocks) * 2);
return (0);
}
int
bitmask_should_resize(const struct bitmask_head *bh)
{
return (bitmask_get_resize_items(bh) != 0);
}
#if 0
uint32_t
_bitmask_get_blocks(uint32_t items)
{
return (items / BLOCK_ITEMS);
}
#endif
size_t
bitmask_get_size(uint32_t items)
{
#if _KERNEL
KASSERT((items % BLOCK_ITEMS) == 0,
("bitmask size needs to power of 2 and greater or equal to %zu",
BLOCK_ITEMS));
#else
assert((items % BLOCK_ITEMS) == 0);
#endif
return (items / 8);
}
static void
_bitmask_init_idx(void *_idx, uint32_t items)
{
size_t size = bitmask_get_size(items);
u_long *idx = (u_long *)_idx;
/* Mark all as free */
memset(idx, 0xFF, size);
*idx &= ~(u_long)1; /* Always skip index 0 */
}
/*
* _try_merge api to allow shrinking?
*/
int
bitmask_copy(const struct bitmask_head *bi, void *new_idx, uint32_t new_items)
{
uint32_t new_blocks = _BLOCKS_TO_ITEMS(new_items);
_bitmask_init_idx(new_idx, new_items);
if (bi->blocks < new_blocks) {
/* extend current blocks */
if (bi->blocks > 0)
memcpy(new_idx, bi->idx, _BLOCKS_TO_SZ(bi->blocks));
return (0);
} else {
/* XXX: ensure all other blocks are non-zero */
for (int i = new_blocks; i < bi->blocks; i++) {
}
return (1);
}
}
void
bitmask_swap(struct bitmask_head *bh, void *new_idx, uint32_t new_items, void **pidx)
{
void *old_ptr;
old_ptr = bh->idx;
bh->idx = (u_long *)new_idx;
bh->blocks = _ITEMS_TO_BLOCKS(new_items);
if (pidx != NULL)
*pidx = old_ptr;
}
/*
* Allocate new index in given instance and stores in in @pidx.
* Returns 0 on success.
*/
int
bitmask_alloc_idx(struct bitmask_head *bi, uint16_t *pidx)
{
u_long *mask;
int i, off, v;
off = bi->free_off;
mask = &bi->idx[off];
for (i = off; i < bi->blocks; i++, mask++) {
if ((v = ffsl(*mask)) == 0)
continue;
/* Mark as busy */
*mask &= ~ ((u_long)1 << (v - 1));
bi->free_off = i;
v = BLOCK_ITEMS * i + v - 1;
*pidx = v;
bi->items_count++;
return (0);
}
return (1);
}
/*
* Removes index from given set.
* Returns 0 on success.
*/
int
bitmask_free_idx(struct bitmask_head *bi, uint16_t idx)
{
u_long *mask;
int i, v;
if (idx == 0)
return (1);
i = idx / BLOCK_ITEMS;
v = idx % BLOCK_ITEMS;
if (i >= bi->blocks)
return (1);
mask = &bi->idx[i];
if ((*mask & ((u_long)1 << v)) != 0)
return (1);
/* Mark as free */
*mask |= (u_long)1 << v;
bi->items_count--;
/* Update free offset */
if (bi->free_off > i)
bi->free_off = i;
return (0);
}
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