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7db7d9f3 | 1 | // SPDX-License-Identifier: GPL-2.0 |
68e039f9 | 2 | /* Copyright (C) 2006-2020 B.A.T.M.A.N. contributors: |
c6c8fea2 SE |
3 | * |
4 | * Simon Wunderlich, Marek Lindner | |
c6c8fea2 SE |
5 | */ |
6 | ||
c6c8fea2 | 7 | #include "bitarray.h" |
1e2c2a4f | 8 | #include "main.h" |
c6c8fea2 | 9 | |
1e2c2a4f | 10 | #include <linux/bitmap.h> |
c6c8fea2 | 11 | |
ba412080 SE |
12 | #include "log.h" |
13 | ||
c6c8fea2 | 14 | /* shift the packet array by n places. */ |
6b5e971a | 15 | static void batadv_bitmap_shift_left(unsigned long *seq_bits, s32 n) |
c6c8fea2 | 16 | { |
42d0b044 | 17 | if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE) |
c6c8fea2 SE |
18 | return; |
19 | ||
42d0b044 | 20 | bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE); |
c6c8fea2 SE |
21 | } |
22 | ||
7afcbbef | 23 | /** |
7e9a8c2c | 24 | * batadv_bit_get_packet() - receive and process one packet within the sequence |
7afcbbef SE |
25 | * number window |
26 | * @priv: the bat priv with all the soft interface information | |
27 | * @seq_bits: pointer to the sequence number receive packet | |
28 | * @seq_num_diff: difference between the current/received sequence number and | |
29 | * the last sequence number | |
30 | * @set_mark: whether this packet should be marked in seq_bits | |
c6c8fea2 | 31 | * |
4b426b10 SE |
32 | * Return: true if the window was moved (either new or very old), |
33 | * false if the window was not moved/shifted. | |
c6c8fea2 | 34 | */ |
4b426b10 SE |
35 | bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits, |
36 | s32 seq_num_diff, int set_mark) | |
c6c8fea2 | 37 | { |
56303d34 | 38 | struct batadv_priv *bat_priv = priv; |
c6c8fea2 SE |
39 | |
40 | /* sequence number is slightly older. We already got a sequence number | |
9cfc7bd6 SE |
41 | * higher than this one, so we just mark it. |
42 | */ | |
42d0b044 | 43 | if (seq_num_diff <= 0 && seq_num_diff > -BATADV_TQ_LOCAL_WINDOW_SIZE) { |
c6c8fea2 | 44 | if (set_mark) |
9b4a1159 | 45 | batadv_set_bit(seq_bits, -seq_num_diff); |
4b426b10 | 46 | return false; |
c6c8fea2 SE |
47 | } |
48 | ||
49 | /* sequence number is slightly newer, so we shift the window and | |
9cfc7bd6 SE |
50 | * set the mark if required |
51 | */ | |
42d0b044 | 52 | if (seq_num_diff > 0 && seq_num_diff < BATADV_TQ_LOCAL_WINDOW_SIZE) { |
0f5f9322 | 53 | batadv_bitmap_shift_left(seq_bits, seq_num_diff); |
c6c8fea2 SE |
54 | |
55 | if (set_mark) | |
9b4a1159 | 56 | batadv_set_bit(seq_bits, 0); |
4b426b10 | 57 | return true; |
c6c8fea2 SE |
58 | } |
59 | ||
60 | /* sequence number is much newer, probably missed a lot of packets */ | |
42d0b044 SE |
61 | if (seq_num_diff >= BATADV_TQ_LOCAL_WINDOW_SIZE && |
62 | seq_num_diff < BATADV_EXPECTED_SEQNO_RANGE) { | |
39c75a51 | 63 | batadv_dbg(BATADV_DBG_BATMAN, bat_priv, |
1eda58bf SE |
64 | "We missed a lot of packets (%i) !\n", |
65 | seq_num_diff - 1); | |
42d0b044 | 66 | bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE); |
c6c8fea2 | 67 | if (set_mark) |
9b4a1159 | 68 | batadv_set_bit(seq_bits, 0); |
4b426b10 | 69 | return true; |
c6c8fea2 SE |
70 | } |
71 | ||
72 | /* received a much older packet. The other host either restarted | |
73 | * or the old packet got delayed somewhere in the network. The | |
74 | * packet should be dropped without calling this function if the | |
9cfc7bd6 | 75 | * seqno window is protected. |
8e7c15d6 SE |
76 | * |
77 | * seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE | |
78 | * or | |
79 | * seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE | |
9cfc7bd6 | 80 | */ |
8e7c15d6 SE |
81 | batadv_dbg(BATADV_DBG_BATMAN, bat_priv, |
82 | "Other host probably restarted!\n"); | |
c6c8fea2 | 83 | |
8e7c15d6 SE |
84 | bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE); |
85 | if (set_mark) | |
86 | batadv_set_bit(seq_bits, 0); | |
c6c8fea2 | 87 | |
4b426b10 | 88 | return true; |
c6c8fea2 | 89 | } |