Merge branch 'NSS-335'

1 files changed, 94 insertions, 0 deletions

diff --git a/security/nss/lib/ssl/sslbloom.c b/security/nss/lib/ssl/sslbloom.c
new file mode 100644
index 000000000..3d5f9d1f1
--- /dev/null
+++ b/security/nss/lib/ssl/sslbloom.c
@@ -0,0 +1,94 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * A bloom filter.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "sslbloom.h"
+#include "prnetdb.h"
+#include "secport.h"
+
+static inline unsigned int
+sslBloom_Size(unsigned int bits)
+{
+    return (bits >= 3) ? (1 << (bits - 3)) : 1;
+}
+
+SECStatus
+sslBloom_Init(sslBloomFilter *filter, unsigned int k, unsigned int bits)
+{
+    PORT_Assert(filter);
+    PORT_Assert(bits > 0);
+    PORT_Assert(bits <= sizeof(PRUint32) * 8);
+    PORT_Assert(k > 0);
+
+    filter->filter = PORT_ZNewArray(PRUint8, sslBloom_Size(bits));
+    if (!filter->filter) {
+        return SECFailure; /* Error code already set. */
+    }
+
+    filter->k = k;
+    filter->bits = bits;
+    return SECSuccess;
+}
+
+void
+sslBloom_Zero(sslBloomFilter *filter)
+{
+    PORT_Memset(filter->filter, 0, sslBloom_Size(filter->bits));
+}
+
+void
+sslBloom_Fill(sslBloomFilter *filter)
+{
+    PORT_Memset(filter->filter, 0xff, sslBloom_Size(filter->bits));
+}
+
+static PRBool
+sslBloom_AddOrCheck(sslBloomFilter *filter, const PRUint8 *hashes, PRBool add)
+{
+    unsigned int iteration;
+    unsigned int bitIndex;
+    PRUint32 tmp = 0;
+    PRUint8 mask;
+    unsigned int bytes = (filter->bits + 7) / 8;
+    unsigned int shift = (bytes * 8) - filter->bits;
+    PRBool found = PR_TRUE;
+
+    PORT_Assert(bytes <= sizeof(unsigned int));
+
+    for (iteration = 0; iteration < filter->k; ++iteration) {
+        PORT_Memcpy(((PRUint8 *)&tmp) + (sizeof(tmp) - bytes),
+                    hashes, bytes);
+        hashes += bytes;
+        bitIndex = PR_ntohl(tmp) >> shift;
+
+        mask = 1 << (bitIndex % 8);
+        found = found && filter->filter[bitIndex / 8] & mask;
+        if (add) {
+            filter->filter[bitIndex / 8] |= mask;
+        }
+    }
+    return found;
+}
+
+PRBool
+sslBloom_Add(sslBloomFilter *filter, const PRUint8 *hashes)
+{
+    return sslBloom_AddOrCheck(filter, hashes, PR_TRUE);
+}
+
+PRBool
+sslBloom_Check(sslBloomFilter *filter, const PRUint8 *hashes)
+{
+    return sslBloom_AddOrCheck(filter, hashes, PR_FALSE);
+}
+
+void
+sslBloom_Destroy(sslBloomFilter *filter)
+{
+    PORT_Free(filter->filter);
+    PORT_Memset(filter, 0, sizeof(*filter));
+}