net/batman-adv/bitarray.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Copyright (C) 2006-2017  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_ */