xref: /freebsd/sys/net/route/nhop_utils.h (revision cc68614da8232d8baaca0ae0d0dd8f890f06623e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2020 Alexander V. Chernikov
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 
30 #ifndef	_NET_ROUTE_NHOP_UTILS_H_
31 #define	_NET_ROUTE_NHOP_UTILS_H_
32 
33 /* Chained hash table */
34 struct _cht_head {
35 	uint32_t	hash_size;
36 	uint32_t	items_count;
37 	void		**ptr;
38 };
39 
40 static inline uint32_t
41 _cht_get_resize_size(const struct _cht_head *head)
42 {
43 	uint32_t new_size = 0;
44 
45 	if ((head->items_count * 2 > head->hash_size) && (head->hash_size < 65536))
46 		new_size = head->hash_size * 2;
47 	else if ((head->items_count * 4 < head->hash_size) && head->hash_size > 16)
48 		new_size = head->hash_size / 2;
49 
50 	return (new_size);
51 }
52 
53 static inline int
54 _cht_need_resize(const struct _cht_head *head)
55 {
56 
57 	return (_cht_get_resize_size(head) > 0);
58 }
59 
60 #ifndef	typeof
61 #define	typeof	__typeof
62 #endif
63 
64 #define	CHT_SLIST_NEED_RESIZE(_head)		\
65 	_cht_need_resize((const struct _cht_head *)(_head))
66 #define	CHT_SLIST_GET_RESIZE_BUCKETS(_head)	\
67 	_cht_get_resize_size((const struct _cht_head *)(_head))
68 #define	CHT_SLIST_GET_RESIZE_SIZE(_buckets)	((_buckets) * sizeof(void *))
69 
70 #define	CHT_SLIST_DEFINE(_HNAME, _ITEM_TYPE)	\
71 struct _HNAME##_head {				\
72 	uint32_t	hash_size;		\
73 	uint32_t	items_count;		\
74 	_ITEM_TYPE	**ptr;			\
75 }
76 
77 #define	CHT_SLIST_INIT(_head, _ptr, _num_buckets)	\
78 	(_head)->hash_size = _num_buckets;		\
79 	(_head)->items_count = 0;			\
80 	(_head)->ptr = _ptr;
81 
82 /* Default hash method for constant-size keys */
83 
84 #define	CHT_GET_BUCK(_head, _PX, _key)	_PX##_hash_key(_key) & ((_head)->hash_size - 1)
85 #define	CHT_GET_BUCK_OBJ(_head, _PX, _obj)	_PX##_hash_obj(_obj) & ((_head)->hash_size - 1)
86 
87 #define	CHT_FIRST(_head, idx)	_CHT_FIRST((_head)->ptr, idx)
88 #define	_CHT_FIRST(_ptr, idx)	(_ptr)[idx]
89 
90 #define	CHT_SLIST_FIND(_head, _PX, _key, _ret) do {			\
91 	uint32_t _buck = CHT_GET_BUCK(_head, _PX, _key);		\
92 	_ret = CHT_FIRST(_head, _buck);					\
93 	for ( ; _ret != NULL; _ret = _PX##_next(_ret)) {		\
94 		if (_PX##_cmp(_key, (_ret)))				\
95 			break;						\
96 	}								\
97 } while(0)
98 
99 /*
100  * hash_obj, nhop_cmp
101  */
102 #define	CHT_SLIST_FIND_BYOBJ(_head, _PX, _obj, _ret) do {		\
103 	uint32_t _buck = CHT_GET_BUCK_OBJ(_head, _PX, _obj);		\
104 	_ret = CHT_FIRST(_head, _buck);					\
105 	for ( ; _ret != NULL; _ret = _PX##_next(_ret)) {		\
106 		if (_PX##_cmp(_obj, _ret))				\
107 			break;						\
108 	}								\
109 } while(0)
110 
111 #define	CHT_SLIST_INSERT_HEAD(_head, _PX, _obj) do {			\
112 	uint32_t _buck = CHT_GET_BUCK_OBJ(_head, _PX, _obj);		\
113 	_PX##_next(_obj) = CHT_FIRST(_head, _buck);			\
114 	CHT_FIRST(_head, _buck) = _obj;					\
115 	(_head)->items_count++;						\
116 } while(0)
117 
118 #define	CHT_SLIST_REMOVE(_head, _PX, _obj, _ret) do {			\
119 	typeof(*(_head)->ptr) _tmp;					\
120 	uint32_t _buck = CHT_GET_BUCK_OBJ(_head, _PX, _obj);		\
121 	_ret = CHT_FIRST(_head, _buck);					\
122 	_tmp = NULL;							\
123 	for ( ; _ret != NULL; _tmp = _ret, _ret = _PX##_next(_ret)) {	\
124 		if (_obj == _ret)					\
125 			break;						\
126 	}								\
127 	if (_ret != NULL) {						\
128 		if (_tmp == NULL)					\
129 			CHT_FIRST(_head, _buck) = _PX##_next(_ret);	\
130 		else							\
131 			_PX##_next(_tmp) = _PX##_next(_ret);		\
132 		(_head)->items_count--;					\
133 	}								\
134 } while(0)
135 #define	CHT_SLIST_REMOVE_BYOBJ	CHT_SLIST_REMOVE
136 
137 #define	CHT_SLIST_FOREACH(_head, _PX, _x)				\
138 	for (uint32_t _i = 0; _i < (_head)->hash_size; _i++) {		\
139 		for (_x = CHT_FIRST(_head, _i); _x; _x = _PX##_next(_x))
140 #define	CHT_SLIST_FOREACH_END	}
141 
142 #define	CHT_SLIST_RESIZE(_head, _PX, _new_void_ptr, _new_hsize)		\
143 	uint32_t _new_idx;						\
144 	typeof((_head)->ptr) _new_ptr = (void *)_new_void_ptr;		\
145 	typeof(*(_head)->ptr) _x, _y;					\
146 	for (uint32_t _old_idx = 0; _old_idx < (_head)->hash_size; _old_idx++) {\
147 		_x = CHT_FIRST(_head, _old_idx);			\
148 		_y = _x;						\
149 		while (_y != NULL) {					\
150 			_y = _PX##_next(_x);				\
151 			_new_idx = _PX##_hash_obj(_x) & (_new_hsize - 1);\
152 			_PX##_next(_x) = _CHT_FIRST(_new_ptr, _new_idx);\
153 			_CHT_FIRST(_new_ptr, _new_idx) = _x;		\
154 			_x = _y;					\
155 		}							\
156 	}								\
157 	(_head)->hash_size = _new_hsize;				\
158 	_new_void_ptr = (void *)(_head)->ptr;				\
159 	(_head)->ptr = _new_ptr;
160 
161 /* bitmasks */
162 
163 struct bitmask_head {
164 	uint16_t	free_off; /* index of the first potentially free block */
165 	uint16_t	blocks; /* number of 4/8-byte blocks in the index */
166 	uint32_t	items_count; /* total number of items */
167 	u_long		*idx;
168 };
169 
170 size_t bitmask_get_size(uint32_t items);
171 uint32_t bitmask_get_resize_items(const struct bitmask_head *nh);
172 int bitmask_should_resize(const struct bitmask_head *bh);
173 void bitmask_swap(struct bitmask_head *bh, void *new_idx, uint32_t new_items, void **pidx);
174 void bitmask_init(struct bitmask_head *bh, void *idx, uint32_t num_items);
175 int bitmask_copy(const struct bitmask_head *bi, void *new_idx, uint32_t new_items);
176 int bitmask_alloc_idx(struct bitmask_head *bi, uint16_t *pidx);
177 int bitmask_free_idx(struct bitmask_head *bi, uint16_t idx);
178 
179 #endif
180