xref: /openbmc/linux/net/batman-adv/bitarray.h (revision d2574c33)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (C) 2006-2019  B.A.T.M.A.N. contributors:
3  *
4  * Simon Wunderlich, Marek Lindner
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of version 2 of the GNU General Public
8  * License as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #ifndef _NET_BATMAN_ADV_BITARRAY_H_
20 #define _NET_BATMAN_ADV_BITARRAY_H_
21 
22 #include "main.h"
23 
24 #include <linux/bitops.h>
25 #include <linux/compiler.h>
26 #include <linux/stddef.h>
27 #include <linux/types.h>
28 
29 /**
30  * batadv_test_bit() - check if bit is set in the current window
31  *
32  * @seq_bits: pointer to the sequence number receive packet
33  * @last_seqno: latest sequence number in seq_bits
34  * @curr_seqno: sequence number to test for
35  *
36  * Return: true if the corresponding bit in the given seq_bits indicates true
37  * and curr_seqno is within range of last_seqno. Otherwise returns false.
38  */
39 static inline bool batadv_test_bit(const unsigned long *seq_bits,
40 				   u32 last_seqno, u32 curr_seqno)
41 {
42 	s32 diff;
43 
44 	diff = last_seqno - curr_seqno;
45 	if (diff < 0 || diff >= BATADV_TQ_LOCAL_WINDOW_SIZE)
46 		return false;
47 	return test_bit(diff, seq_bits) != 0;
48 }
49 
50 /**
51  * batadv_set_bit() - Turn corresponding bit on, so we can remember that we got
52  *  the packet
53  * @seq_bits: bitmap of the packet receive window
54  * @n: relative sequence number of newly received packet
55  */
56 static inline void batadv_set_bit(unsigned long *seq_bits, s32 n)
57 {
58 	/* if too old, just drop it */
59 	if (n < 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
60 		return;
61 
62 	set_bit(n, seq_bits); /* turn the position on */
63 }
64 
65 bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
66 			   s32 seq_num_diff, int set_mark);
67 
68 #endif /* _NET_BATMAN_ADV_BITARRAY_H_ */
69