1 files changed, 139 insertions, 0 deletions
diff --git a/third_party/libsrtp/src/crypto/replay/rdb.c b/third_party/libsrtp/src/crypto/replay/rdb.c
new file mode 100644
index 0000000000..d8c2b3838e
--- /dev/null
+++ b/third_party/libsrtp/src/crypto/replay/rdb.c
@@ -0,0 +1,139 @@
+/*
+ * rdb.c
+ *
+ * Implements a replay database for packet security
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2017, 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.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "rdb.h"
+
+#define rdb_bits_in_bitmask (8 * sizeof(v128_t))
+
+/*
+ * 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
+ *
+ */
+
+/* srtp_rdb_init initalizes rdb */
+srtp_err_status_t srtp_rdb_init(srtp_rdb_t *rdb)
+{
+    v128_set_to_zero(&rdb->bitmask);
+    rdb->window_start = 0;
+    return srtp_err_status_ok;
+}
+
+/*
+ * srtp_rdb_check checks to see if index appears in rdb
+ */
+srtp_err_status_t srtp_rdb_check(const srtp_rdb_t *rdb, uint32_t p_index)
+{
+    /* if the index appears after (or at very end of) the window, its good */
+    if (p_index >= rdb->window_start + rdb_bits_in_bitmask) {
+        return srtp_err_status_ok;
+    }
+
+    /* if the index appears before the window, its bad */
+    if (p_index < rdb->window_start) {
+        return srtp_err_status_replay_old;
+    }
+
+    /* otherwise, the index appears within the window, so check the bitmask */
+    if (v128_get_bit(&rdb->bitmask, (p_index - rdb->window_start)) == 1) {
+        return srtp_err_status_replay_fail;
+    }
+
+    /* otherwise, the index is okay */
+    return srtp_err_status_ok;
+}
+
+/*
+ * srtp_rdb_add_index adds index to srtp_rdb_t (and does *not* check if
+ * index appears in db)
+ *
+ * this function should be called only after srtp_rdb_check has
+ * indicated that the index does not appear in the rdb, e.g., a mutex
+ * should protect the rdb between these calls
+ */
+srtp_err_status_t srtp_rdb_add_index(srtp_rdb_t *rdb, uint32_t p_index)
+{
+    unsigned int delta;
+
+    if (p_index < rdb->window_start)
+        return srtp_err_status_replay_fail;
+
+    delta = (p_index - rdb->window_start);
+    if (delta < rdb_bits_in_bitmask) {
+        /* if the p_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 - 1);
+        rdb->window_start += delta;
+    }
+
+    return srtp_err_status_ok;
+}
+
+srtp_err_status_t srtp_rdb_increment(srtp_rdb_t *rdb)
+{
+    if (rdb->window_start >= 0x7fffffff) {
+        return srtp_err_status_key_expired;
+    }
+    ++rdb->window_start;
+    return srtp_err_status_ok;
+}
+
+uint32_t srtp_rdb_get_value(const srtp_rdb_t *rdb)
+{
+    return rdb->window_start;
+}