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7db7d9f369
The "Linux kernel licensing rules" require that each file has a SPDX license identifier as first line (and sometimes as second line). The FSFE REUSE practices [1] would also require the same tags but have no restrictions on the placement in the source file. Using the "Linux kernel licensing rules" is therefore also fulfilling the FSFE REUSE practices requirements at the same time. [1] https://reuse.software/practices/ Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2006-2017 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, see <http://www.gnu.org/licenses/>.
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*/
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#include "bitarray.h"
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#include "main.h"
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#include <linux/bitmap.h>
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#include "log.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, s32 n)
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{
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if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
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return;
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bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE);
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}
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/**
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* batadv_bit_get_packet - receive and process one packet within the sequence
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* number window
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* @priv: the bat priv with all the soft interface information
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* @seq_bits: pointer to the sequence number receive packet
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* @seq_num_diff: difference between the current/received sequence number and
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* the last sequence number
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* @set_mark: whether this packet should be marked in seq_bits
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*
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* Return: true if the window was moved (either new or very old),
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* false if the window was not moved/shifted.
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*/
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bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
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s32 seq_num_diff, int set_mark)
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{
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struct batadv_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 > -BATADV_TQ_LOCAL_WINDOW_SIZE) {
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if (set_mark)
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batadv_set_bit(seq_bits, -seq_num_diff);
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return false;
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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 < BATADV_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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batadv_set_bit(seq_bits, 0);
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return true;
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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 >= BATADV_TQ_LOCAL_WINDOW_SIZE &&
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seq_num_diff < BATADV_EXPECTED_SEQNO_RANGE) {
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batadv_dbg(BATADV_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, BATADV_TQ_LOCAL_WINDOW_SIZE);
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if (set_mark)
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batadv_set_bit(seq_bits, 0);
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return true;
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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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* seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE
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* or
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* seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE
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*/
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Other host probably restarted!\n");
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bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
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if (set_mark)
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batadv_set_bit(seq_bits, 0);
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return true;
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}
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