1 files changed, 61 insertions, 0 deletions
diff --git a/src/tls/hello_verify.cpp b/src/tls/hello_verify.cpp
new file mode 100644
index 000000000..e844d7f72
--- /dev/null
+++ b/src/tls/hello_verify.cpp
@@ -0,0 +1,61 @@
+/*
+* DTLS Hello Verify Request
+* (C) 2012 Jack Lloyd
+*
+* Released under the terms of the Botan license
+*/
+
+#include <botan/internal/tls_messages.h>
+#include <botan/lookup.h>
+#include <memory>
+
+namespace Botan {
+
+namespace TLS {
+
+Hello_Verify_Request::Hello_Verify_Request(const MemoryRegion<byte>& buf)
+   {
+   if(buf.size() < 3)
+      throw Decoding_Error("Hello verify request too small");
+
+   if(buf[0] != 254 || (buf[1] != 255 && buf[1] != 253))
+      throw Decoding_Error("Unknown version from server in hello verify request");
+
+   m_cookie.resize(buf.size() - 2);
+   copy_mem(&m_cookie[0], &buf[2], buf.size() - 2);
+   }
+
+Hello_Verify_Request::Hello_Verify_Request(const MemoryVector<byte>& client_hello_bits,
+                                           const std::string& client_identity,
+                                           const SymmetricKey& secret_key)
+   {
+   std::unique_ptr<MessageAuthenticationCode> hmac(get_mac("HMAC(SHA-256)"));
+   hmac->set_key(secret_key);
+
+   hmac->update_be(client_hello_bits.size());
+   hmac->update(client_hello_bits);
+   hmac->update_be(client_identity.size());
+   hmac->update(client_identity);
+
+   m_cookie = hmac->final();
+   }
+
+MemoryVector<byte> Hello_Verify_Request::serialize() const
+   {
+   /* DTLS 1.2 server implementations SHOULD use DTLS version 1.0
+      regardless of the version of TLS that is expected to be
+      negotiated (RFC 6347, section 4.2.1)
+   */
+
+   Protocol_Version format_version(Protocol_Version::TLS_V11);
+
+   MemoryVector<byte> bits;
+   bits.push_back(format_version.major_version());
+   bits.push_back(format_version.minor_version());
+   bits += m_cookie;
+   return bits;
+   }
+
+}
+
+}