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9cfc7bd608
batman-adv doesn't follow the style for multiline comments that David S. Miller prefers. All comments should be reformatted to follow this consistent style to make the code slightly more readable. Signed-off-by: Sven Eckelmann <sven@narfation.org>
99 lines
2.8 KiB
C
99 lines
2.8 KiB
C
/* Copyright (C) 2006-2012 B.A.T.M.A.N. contributors:
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*
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* Simon Wunderlich, Marek Lindner
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*/
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#include "main.h"
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#include "bitarray.h"
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#include <linux/bitops.h>
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/* shift the packet array by n places. */
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static void batadv_bitmap_shift_left(unsigned long *seq_bits, int32_t n)
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{
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if (n <= 0 || n >= TQ_LOCAL_WINDOW_SIZE)
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return;
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bitmap_shift_left(seq_bits, seq_bits, n, TQ_LOCAL_WINDOW_SIZE);
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}
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/* receive and process one packet within the sequence number window.
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*
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* returns:
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* 1 if the window was moved (either new or very old)
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* 0 if the window was not moved/shifted.
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*/
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int batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
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int32_t seq_num_diff, int set_mark)
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{
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struct bat_priv *bat_priv = priv;
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/* sequence number is slightly older. We already got a sequence number
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* higher than this one, so we just mark it.
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*/
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if ((seq_num_diff <= 0) && (seq_num_diff > -TQ_LOCAL_WINDOW_SIZE)) {
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if (set_mark)
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bat_set_bit(seq_bits, -seq_num_diff);
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return 0;
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}
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/* sequence number is slightly newer, so we shift the window and
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* set the mark if required
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*/
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if ((seq_num_diff > 0) && (seq_num_diff < TQ_LOCAL_WINDOW_SIZE)) {
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batadv_bitmap_shift_left(seq_bits, seq_num_diff);
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if (set_mark)
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bat_set_bit(seq_bits, 0);
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return 1;
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}
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/* sequence number is much newer, probably missed a lot of packets */
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if ((seq_num_diff >= TQ_LOCAL_WINDOW_SIZE) &&
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(seq_num_diff < EXPECTED_SEQNO_RANGE)) {
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bat_dbg(DBG_BATMAN, bat_priv,
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"We missed a lot of packets (%i) !\n",
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seq_num_diff - 1);
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bitmap_zero(seq_bits, TQ_LOCAL_WINDOW_SIZE);
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if (set_mark)
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bat_set_bit(seq_bits, 0);
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return 1;
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}
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/* received a much older packet. The other host either restarted
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* or the old packet got delayed somewhere in the network. The
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* packet should be dropped without calling this function if the
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* seqno window is protected.
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*/
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if ((seq_num_diff <= -TQ_LOCAL_WINDOW_SIZE) ||
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(seq_num_diff >= EXPECTED_SEQNO_RANGE)) {
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bat_dbg(DBG_BATMAN, bat_priv,
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"Other host probably restarted!\n");
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bitmap_zero(seq_bits, TQ_LOCAL_WINDOW_SIZE);
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if (set_mark)
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bat_set_bit(seq_bits, 0);
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return 1;
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}
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/* never reached */
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return 0;
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}
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