xref: /linux/net/batman-adv/bitarray.h (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /* Copyright (C) 2006-2012 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, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA
18  */
19 
20 #ifndef _NET_BATMAN_ADV_BITARRAY_H_
21 #define _NET_BATMAN_ADV_BITARRAY_H_
22 
23 /* Returns 1 if the corresponding bit in the given seq_bits indicates true
24  * and curr_seqno is within range of last_seqno. Otherwise returns 0.
25  */
26 static inline int batadv_test_bit(const unsigned long *seq_bits,
27 				  uint32_t last_seqno, uint32_t curr_seqno)
28 {
29 	int32_t diff;
30 
31 	diff = last_seqno - curr_seqno;
32 	if (diff < 0 || diff >= BATADV_TQ_LOCAL_WINDOW_SIZE)
33 		return 0;
34 	else
35 		return test_bit(diff, seq_bits) != 0;
36 }
37 
38 /* turn corresponding bit on, so we can remember that we got the packet */
39 static inline void batadv_set_bit(unsigned long *seq_bits, int32_t n)
40 {
41 	/* if too old, just drop it */
42 	if (n < 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
43 		return;
44 
45 	set_bit(n, seq_bits); /* turn the position on */
46 }
47 
48 /* receive and process one packet, returns 1 if received seq_num is considered
49  * new, 0 if old
50  */
51 int batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
52 			  int32_t seq_num_diff, int set_mark);
53 
54 #endif /* _NET_BATMAN_ADV_BITARRAY_H_ */
55