Differential D24232 Diff 70089 sys/net/route/nhop_utils.c

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sys/net/route/nhop_utils.c

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				/*-
				* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
				*
				* 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.
				*
				* $FreeBSD$
				*/

				#include <sys/cdefs.h>
				#include "opt_inet.h"
				#include "opt_route.h"
				#include "opt_mpath.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);
				}