xref: /openbmc/linux/net/batman-adv/bitarray.h (revision 7587eb18)
1 /* Copyright (C) 2006-2016  B.A.T.M.A.N. contributors:
2  *
3  * Simon Wunderlich, Marek Lindner
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of version 2 of the GNU General Public
7  * License as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #ifndef _NET_BATMAN_ADV_BITARRAY_H_
19 #define _NET_BATMAN_ADV_BITARRAY_H_
20 
21 #include "main.h"
22 
23 #include <linux/bitops.h>
24 #include <linux/compiler.h>
25 #include <linux/stddef.h>
26 #include <linux/types.h>
27 
28 /**
29  * batadv_test_bit - check if bit is set in the current window
30  *
31  * @seq_bits: pointer to the sequence number receive packet
32  * @last_seqno: latest sequence number in seq_bits
33  * @curr_seqno: sequence number to test for
34  *
35  * Return: true if the corresponding bit in the given seq_bits indicates true
36  * and curr_seqno is within range of last_seqno. Otherwise returns false.
37  */
38 static inline bool batadv_test_bit(const unsigned long *seq_bits,
39 				   u32 last_seqno, u32 curr_seqno)
40 {
41 	s32 diff;
42 
43 	diff = last_seqno - curr_seqno;
44 	if (diff < 0 || diff >= BATADV_TQ_LOCAL_WINDOW_SIZE)
45 		return false;
46 	return test_bit(diff, seq_bits) != 0;
47 }
48 
49 /* turn corresponding bit on, so we can remember that we got the packet */
50 static inline void batadv_set_bit(unsigned long *seq_bits, s32 n)
51 {
52 	/* if too old, just drop it */
53 	if (n < 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
54 		return;
55 
56 	set_bit(n, seq_bits); /* turn the position on */
57 }
58 
59 bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
60 			   s32 seq_num_diff, int set_mark);
61 
62 #endif /* _NET_BATMAN_ADV_BITARRAY_H_ */
63