net/batman-adv/bitarray.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Copyright (C) 2006-2020  B.A.T.M.A.N. contributors:
   3  *
   4  * Simon Wunderlich, Marek Lindner
   5  */
   6
   7 #ifndef _NET_BATMAN_ADV_BITARRAY_H_
   8 #define _NET_BATMAN_ADV_BITARRAY_H_
   9
  10 #include "main.h"
  11
  12 #include <linux/bitops.h>
  13 #include <linux/compiler.h>
  14 #include <linux/stddef.h>
  15 #include <linux/types.h>
  16
  17 /**
  18  * batadv_test_bit() - check if bit is set in the current window
  19  *
  20  * @seq_bits: pointer to the sequence number receive packet
  21  * @last_seqno: latest sequence number in seq_bits
  22  * @curr_seqno: sequence number to test for
  23  *
  24  * Return: true if the corresponding bit in the given seq_bits indicates true
  25  * and curr_seqno is within range of last_seqno. Otherwise returns false.
  26  */
  27 static inline bool batadv_test_bit(const unsigned long *seq_bits,
  28                                    u32 last_seqno, u32 curr_seqno)
  29 {
  30         s32 diff;
  31
  32         diff = last_seqno - curr_seqno;
  33         if (diff < 0 || diff >= BATADV_TQ_LOCAL_WINDOW_SIZE)
  34                 return false;
  35         return test_bit(diff, seq_bits) != 0;
  36 }
  37
  38 /**
  39  * batadv_set_bit() - Turn corresponding bit on, so we can remember that we got
  40  *  the packet
  41  * @seq_bits: bitmap of the packet receive window
  42  * @n: relative sequence number of newly received packet
  43  */
  44 static inline void batadv_set_bit(unsigned long *seq_bits, s32 n)
  45 {
  46         /* if too old, just drop it */
  47         if (n < 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
  48                 return;
  49
  50         set_bit(n, seq_bits); /* turn the position on */
  51 }
  52
  53 bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
  54                            s32 seq_num_diff, int set_mark);
  55
  56 #endif /* _NET_BATMAN_ADV_BITARRAY_H_ */