96 lines
2.8 KiB
C
96 lines
2.8 KiB
C
/* Copyright (C) 2006-2013 B.A.T.M.A.N. contributors:
|
|
*
|
|
* Simon Wunderlich, Marek Lindner
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of version 2 of the GNU General Public
|
|
* License as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
* 02110-1301, USA
|
|
*/
|
|
|
|
#include "main.h"
|
|
#include "bitarray.h"
|
|
|
|
#include <linux/bitops.h>
|
|
|
|
/* shift the packet array by n places. */
|
|
static void batadv_bitmap_shift_left(unsigned long *seq_bits, int32_t n)
|
|
{
|
|
if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
|
|
return;
|
|
|
|
bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE);
|
|
}
|
|
|
|
|
|
/* receive and process one packet within the sequence number window.
|
|
*
|
|
* returns:
|
|
* 1 if the window was moved (either new or very old)
|
|
* 0 if the window was not moved/shifted.
|
|
*/
|
|
int batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
|
|
int32_t seq_num_diff, int set_mark)
|
|
{
|
|
struct batadv_priv *bat_priv = priv;
|
|
|
|
/* sequence number is slightly older. We already got a sequence number
|
|
* higher than this one, so we just mark it.
|
|
*/
|
|
if (seq_num_diff <= 0 && seq_num_diff > -BATADV_TQ_LOCAL_WINDOW_SIZE) {
|
|
if (set_mark)
|
|
batadv_set_bit(seq_bits, -seq_num_diff);
|
|
return 0;
|
|
}
|
|
|
|
/* sequence number is slightly newer, so we shift the window and
|
|
* set the mark if required
|
|
*/
|
|
if (seq_num_diff > 0 && seq_num_diff < BATADV_TQ_LOCAL_WINDOW_SIZE) {
|
|
batadv_bitmap_shift_left(seq_bits, seq_num_diff);
|
|
|
|
if (set_mark)
|
|
batadv_set_bit(seq_bits, 0);
|
|
return 1;
|
|
}
|
|
|
|
/* sequence number is much newer, probably missed a lot of packets */
|
|
if (seq_num_diff >= BATADV_TQ_LOCAL_WINDOW_SIZE &&
|
|
seq_num_diff < BATADV_EXPECTED_SEQNO_RANGE) {
|
|
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
|
|
"We missed a lot of packets (%i) !\n",
|
|
seq_num_diff - 1);
|
|
bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
|
|
if (set_mark)
|
|
batadv_set_bit(seq_bits, 0);
|
|
return 1;
|
|
}
|
|
|
|
/* received a much older packet. The other host either restarted
|
|
* or the old packet got delayed somewhere in the network. The
|
|
* packet should be dropped without calling this function if the
|
|
* seqno window is protected.
|
|
*
|
|
* seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE
|
|
* or
|
|
* seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE
|
|
*/
|
|
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
|
|
"Other host probably restarted!\n");
|
|
|
|
bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
|
|
if (set_mark)
|
|
batadv_set_bit(seq_bits, 0);
|
|
|
|
return 1;
|
|
}
|