net/batman-adv/bitarray.h

   1 /* Copyright (C) 2006-2017  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_ */