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DependentExtensions/cat/crypt/cookie/CookieJar.hpp

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+/*
+	Copyright (c) 2009-2010 Christopher A. Taylor.  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 LibCat 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 HOLDER 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.
+*/
+
+#ifndef CAT_COOKIE_JAR_HPP
+#define CAT_COOKIE_JAR_HPP
+
+#include <cat/crypt/rand/Fortuna.hpp>
+
+namespace cat {
+
+
+class CookieJar
+{
+    static const int EXPIRE_TIME = 4000; // ms
+    static const int BIN_COUNT = 16; // power of 2
+    static const int BIN_TIME = EXPIRE_TIME / BIN_COUNT;
+    static const int BIN_MASK = BIN_COUNT - 1;
+
+    u32 key[16];
+
+    u32 Salsa6(u32 *x);
+
+    u32 Hash(u32 ip, u16 port, u32 epoch);
+    u32 Hash(const void *address_info, int bytes, u32 epoch);
+
+    u32 GetEpoch();
+    u32 ReconstructEpoch(u32 cookie);
+
+public:
+    // Initialize to a random 512-bit key on startup
+    void Initialize(FortunaOutput *csprng);
+
+    // Thread-safe and lock-free
+    u32 Generate(u32 ip, u16 port);
+    u32 Generate(const void *address_info, int bytes); // bytes <= 48
+
+    // Thread-safe and lock-free
+    bool Verify(u32 ip, u16 port, u32 cookie);
+    bool Verify(const void *address_info, int bytes, u32 cookie); // bytes <= 48
+};
+
+
+} // namespace cat
+
+#endif // CAT_COOKIE_JAR_HPP