| 1 | |
| 2 | |
| 3 | *
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| 4 | * Simon Wunderlich, Marek Lindner
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| 5 |
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| 6 |
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| 7 | #include "bitarray.h"
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| 8 | #include "main.h"
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| 9 |
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| 10 | #include <linux/bitmap.h>
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| 11 |
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| 12 | #include "log.h"
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| 13 |
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| 14 | |
| 15 | * batadv_bitmap_shift_left() - shift the sequence number bitmap left
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| 16 | * @seq_bits: the sequence number bitmap to shift
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| 17 | * @n: number of positions to shift left
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| 18 | *
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| 19 | * Shift @seq_bits by @n positions. No-op if @n is not within the bounds of
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| 20 | * the bitmap.
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| 21 |
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| 22 | static void batadv_bitmap_shift_left(unsigned long *seq_bits, s32 n)
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| 23 | {
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| 24 | if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
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| 25 | return;
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| 26 |
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| 27 | bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE);
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| 28 | }
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| 29 |
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| 30 | |
| 31 | * batadv_bit_get_packet() - receive and process one packet within the sequence
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| 32 | * number window
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| 33 | * @priv: the bat priv with all the mesh interface information
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| 34 | * @seq_bits: pointer to the sequence number bitmap of received packets
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| 35 | * @seq_num_diff: difference between the current/received sequence number and
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| 36 | * the last sequence number
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| 37 | * @set_mark: whether this packet should be marked in seq_bits
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| 38 | *
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| 39 | * Return: true if the window was moved (either new or very old),
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| 40 | * false if the window was not moved/shifted.
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| 41 |
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| 42 | bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
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| 43 | s32 seq_num_diff, int set_mark)
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| 44 | {
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| 45 | struct batadv_priv *bat_priv = priv;
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| 46 |
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| 47 | |
| 48 | * higher than this one, so we just mark it.
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| 49 |
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| 50 | if (seq_num_diff <= 0 && seq_num_diff > -BATADV_TQ_LOCAL_WINDOW_SIZE) {
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| 51 | if (set_mark)
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| 52 | batadv_set_bit(seq_bits, -seq_num_diff);
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| 53 | return false;
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| 54 | }
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| 55 |
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| 56 | |
| 57 | * set the mark if required
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| 58 |
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| 59 | if (seq_num_diff > 0 && seq_num_diff < BATADV_TQ_LOCAL_WINDOW_SIZE) {
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| 60 | batadv_bitmap_shift_left(seq_bits, seq_num_diff);
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| 61 |
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| 62 | if (set_mark)
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| 63 | batadv_set_bit(seq_bits, 0);
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| 64 | return true;
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| 65 | }
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| 66 |
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| 67 |
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| 68 | if (seq_num_diff >= BATADV_TQ_LOCAL_WINDOW_SIZE &&
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| 69 | seq_num_diff < BATADV_EXPECTED_SEQNO_RANGE) {
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| 70 | batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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| 71 | "We missed a lot of packets (%i) !\n",
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| 72 | seq_num_diff - 1);
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| 73 | bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
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| 74 | if (set_mark)
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| 75 | batadv_set_bit(seq_bits, 0);
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| 76 | return true;
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| 77 | }
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| 78 |
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| 79 | |
| 80 | * or the old packet got delayed somewhere in the network. The
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| 81 | * packet should be dropped without calling this function if the
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| 82 | * seqno window is protected.
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| 83 | *
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| 84 | * seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE
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| 85 | * or
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| 86 | * seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE
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| 87 |
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| 88 | batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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| 89 | "Other host probably restarted!\n");
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| 90 |
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| 91 | bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
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| 92 | if (set_mark)
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| 93 | batadv_set_bit(seq_bits, 0);
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| 94 |
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| 95 | return true;
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| 96 | }
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