Ticket #61: imported libsrtp into third_party directory (backported from srtp branch)
git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@1730 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/third_party/srtp/crypto/replay/rdb.c b/third_party/srtp/crypto/replay/rdb.c
new file mode 100644
index 0000000..9f2ea87
--- /dev/null
+++ b/third_party/srtp/crypto/replay/rdb.c
@@ -0,0 +1,137 @@
+/*
+ * rdb.c
+ *
+ * Implements a replay database for packet security
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2006, Cisco Systems, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ *
+ * Neither the name of the Cisco Systems, Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+
+#include "rdb.h"
+
+
+/*
+ * this implementation of a replay database works as follows:
+ *
+ * window_start is the index of the first packet in the window
+ * bitmask a bit-buffer, containing the most recently entered
+ * index as the leftmost bit
+ *
+ */
+
+/* rdb_init initalizes rdb */
+
+err_status_t
+rdb_init(rdb_t *rdb) {
+ v128_set_to_zero(&rdb->bitmask);
+ rdb->window_start = 0;
+ return err_status_ok;
+}
+
+/*
+ * rdb_check checks to see if index appears in rdb
+ */
+
+err_status_t
+rdb_check(const rdb_t *rdb, uint32_t index) {
+
+ /* if the index appears after (or at very end of) the window, its good */
+ if (index >= rdb->window_start + rdb_bits_in_bitmask)
+ return err_status_ok;
+
+ /* if the index appears before the window, its bad */
+ if (index < rdb->window_start)
+ return err_status_replay_old;
+
+ /* otherwise, the index appears within the window, so check the bitmask */
+ if (v128_get_bit(&rdb->bitmask, (index - rdb->window_start)) == 1)
+ return err_status_replay_fail;
+
+ /* otherwise, the index is okay */
+ return err_status_ok;
+}
+
+/*
+ * rdb_add_index adds index to rdb_t (and does *not* check if
+ * index appears in db)
+ *
+ * this function should be called only after rdb_check has
+ * indicated that the index does not appear in the rdb, e.g., a mutex
+ * should protect the rdb between these calls
+ */
+
+err_status_t
+rdb_add_index(rdb_t *rdb, uint32_t index) {
+ int delta;
+
+ /* here we *assume* that index > rdb->window_start */
+
+ delta = (index - rdb->window_start);
+ if (delta < rdb_bits_in_bitmask) {
+
+ /* if the index is within the window, set the appropriate bit */
+ v128_set_bit(&rdb->bitmask, delta);
+
+ } else {
+
+ delta -= rdb_bits_in_bitmask - 1;
+
+ /* shift the window forward by delta bits*/
+ v128_left_shift(&rdb->bitmask, delta);
+ v128_set_bit(&rdb->bitmask, rdb_bits_in_bitmask-delta);
+ rdb->window_start += delta;
+
+ }
+
+ return err_status_ok;
+}
+
+err_status_t
+rdb_increment(rdb_t *rdb) {
+
+ if (rdb->window_start++ > 0x7fffffff)
+ return err_status_key_expired;
+ return err_status_ok;
+}
+
+uint32_t
+rdb_get_value(const rdb_t *rdb) {
+ return rdb->window_start;
+}