| | 1 | /* Copyright (C) 2006-2012 B.A.T.M.A.N. contributors: |
| | 2 | * |
| | 3 | * Simon Wunderlich, Marek Lindner |
| | 4 | * |
| | 5 | * This program is free software; you can redistribute it and/or |
| | 6 | * modify it under the terms of version 2 of the GNU General Public |
| | 7 | * License as published by the Free Software Foundation. |
| | 8 | * |
| | 9 | * This program is distributed in the hope that it will be useful, but |
| | 10 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| | 12 | * General Public License for more details. |
| | 13 | * |
| | 14 | * You should have received a copy of the GNU General Public License |
| | 15 | * along with this program; if not, write to the Free Software |
| | 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| | 17 | * 02110-1301, USA |
| | 18 | */ |
| | 19 | |
| | 20 | #include "main.h" |
| | 21 | #include "bitarray.h" |
| | 22 | |
| | 23 | #include <linux/bitops.h> |
| | 24 | |
| | 25 | /* shift the packet array by n places. */ |
| | 26 | static void batadv_bitmap_shift_left(unsigned long *seq_bits, int32_t n) |
| | 27 | { |
| | 28 | if (n <= 0 || n >= TQ_LOCAL_WINDOW_SIZE) |
| | 29 | return; |
| | 30 | |
| | 31 | bitmap_shift_left(seq_bits, seq_bits, n, TQ_LOCAL_WINDOW_SIZE); |
| | 32 | } |
| | 33 | |
| | 34 | |
| | 35 | /* receive and process one packet within the sequence number window. |
| | 36 | * |
| | 37 | * returns: |
| | 38 | * 1 if the window was moved (either new or very old) |
| | 39 | * 0 if the window was not moved/shifted. |
| | 40 | */ |
| | 41 | int batadv_bit_get_packet(void *priv, unsigned long *seq_bits, |
| | 42 | int32_t seq_num_diff, int set_mark) |
| | 43 | { |
| | 44 | struct bat_priv *bat_priv = priv; |
| | 45 | |
| | 46 | /* sequence number is slightly older. We already got a sequence number |
| | 47 | * higher than this one, so we just mark it. |
| | 48 | */ |
| | 49 | if ((seq_num_diff <= 0) && (seq_num_diff > -TQ_LOCAL_WINDOW_SIZE)) { |
| | 50 | if (set_mark) |
| | 51 | batadv_set_bit(seq_bits, -seq_num_diff); |
| | 52 | return 0; |
| | 53 | } |
| | 54 | |
| | 55 | /* sequence number is slightly newer, so we shift the window and |
| | 56 | * set the mark if required |
| | 57 | */ |
| | 58 | if ((seq_num_diff > 0) && (seq_num_diff < TQ_LOCAL_WINDOW_SIZE)) { |
| | 59 | batadv_bitmap_shift_left(seq_bits, seq_num_diff); |
| | 60 | |
| | 61 | if (set_mark) |
| | 62 | batadv_set_bit(seq_bits, 0); |
| | 63 | return 1; |
| | 64 | } |
| | 65 | |
| | 66 | /* sequence number is much newer, probably missed a lot of packets */ |
| | 67 | if ((seq_num_diff >= TQ_LOCAL_WINDOW_SIZE) && |
| | 68 | (seq_num_diff < EXPECTED_SEQNO_RANGE)) { |
| | 69 | batadv_dbg(DBG_BATMAN, bat_priv, |
| | 70 | "We missed a lot of packets (%i) !\n", |
| | 71 | seq_num_diff - 1); |
| | 72 | bitmap_zero(seq_bits, TQ_LOCAL_WINDOW_SIZE); |
| | 73 | if (set_mark) |
| | 74 | batadv_set_bit(seq_bits, 0); |
| | 75 | return 1; |
| | 76 | } |
| | 77 | |
| | 78 | /* received a much older packet. The other host either restarted |
| | 79 | * or the old packet got delayed somewhere in the network. The |
| | 80 | * packet should be dropped without calling this function if the |
| | 81 | * seqno window is protected. |
| | 82 | */ |
| | 83 | if ((seq_num_diff <= -TQ_LOCAL_WINDOW_SIZE) || |
| | 84 | (seq_num_diff >= EXPECTED_SEQNO_RANGE)) { |
| | 85 | |
| | 86 | batadv_dbg(DBG_BATMAN, bat_priv, |
| | 87 | "Other host probably restarted!\n"); |
| | 88 | |
| | 89 | bitmap_zero(seq_bits, TQ_LOCAL_WINDOW_SIZE); |
| | 90 | if (set_mark) |
| | 91 | batadv_set_bit(seq_bits, 0); |
| | 92 | |
| | 93 | return 1; |
| | 94 | } |
| | 95 | |
| | 96 | /* never reached */ |
| | 97 | return 0; |
| | 98 | } |
projects / deliverable / linux.git / blame_incremental