Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / net / batman-adv / bitarray.c

diff --git a/kernel/net/batman-adv/bitarray.c b/kernel/net/batman-adv/bitarray.c
new file mode 100644 (file)
index 0000000..e3da07a
--- /dev/null
+++ b/kernel/net/batman-adv/bitarray.c
@@ -0,0 +1,92 @@
+/* Copyright (C) 2006-2014 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include "main.h"
+#include "bitarray.h"
+
+#include <linux/bitops.h>
+
+/* shift the packet array by n places. */
+static void batadv_bitmap_shift_left(unsigned long *seq_bits, int32_t n)
+{
+       if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
+               return;
+
+       bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE);
+}
+
+/* receive and process one packet within the sequence number window.
+ *
+ * returns:
+ *  1 if the window was moved (either new or very old)
+ *  0 if the window was not moved/shifted.
+ */
+int batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
+                         int32_t 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 0;
+       }
+
+       /* 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 1;
+       }
+
+       /* 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 1;
+       }
+
+       /* 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 1;
+}