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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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2.6 kB · 89 lines
C
at master
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990// SPDX-License-Identifier: GPL-2.0/* Copyright (C) B.A.T.M.A.N. contributors: * * Simon Wunderlich, Marek Lindner */
#include "bitarray.h"#include "main.h"
#include <linux/bitmap.h>
#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 mesh interface information * @seq_bits: pointer to the sequence number bitmap of received packets * @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;}