From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- net/batman-adv/bitarray.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 net/batman-adv/bitarray.c (limited to 'net/batman-adv/bitarray.c') diff --git a/net/batman-adv/bitarray.c b/net/batman-adv/bitarray.c new file mode 100644 index 000000000..a296a4d85 --- /dev/null +++ b/net/batman-adv/bitarray.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2006-2018 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, see . + */ + +#include "bitarray.h" +#include "main.h" + +#include + +#include "log.h" + +/* shift the packet array by n places. */ +static void batadv_bitmap_shift_left(unsigned long *seq_bits, s32 n) +{ + if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE) + return; + + bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE); +} + +/** + * batadv_bit_get_packet() - receive and process one packet within the sequence + * number window + * @priv: the bat priv with all the soft interface information + * @seq_bits: pointer to the sequence number receive packet + * @seq_num_diff: difference between the current/received sequence number and + * the last sequence number + * @set_mark: whether this packet should be marked in seq_bits + * + * Return: true if the window was moved (either new or very old), + * false if the window was not moved/shifted. + */ +bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits, + s32 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 false; + } + + /* 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 true; + } + + /* 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 true; + } + + /* 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 true; +} -- cgit v1.2.3