From 2d9eff0ecf477b51c9798514dd9ad4222987f060 Mon Sep 17 00:00:00 2001
From: Arthur Britto <ahbritto@gmail.com>
Date: Sun, 29 Apr 2012 16:48:00 -0700
Subject: [PATCH] Add strUnHex and DH support to utils.

---
 src/utils.cpp | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/utils.h   | 10 ++++++++
 2 files changed, 74 insertions(+)

diff --git a/src/utils.cpp b/src/utils.cpp
index 1c454d004..f67a87724 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -24,4 +24,68 @@ char charHex(int iDigit)
 	return iDigit < 10 ? '0' + iDigit : 'A' - 10 + iDigit;
 }
 
+int charUnHex(char cDigit)
+{
+	return cDigit >= '0' && cDigit <= '9'
+		? cDigit - '0'
+		: cDigit >= 'A' && cDigit <= 'F'
+			? cDigit - 'A' + 10
+			: cDigit >= 'a' && cDigit <= 'f'
+				? cDigit - 'a' + 10
+				: -1;
+}
+
+void strUnHex(std::string& strDst, const std::string& strSrc)
+{
+	int	iBytes	= strSrc.size()/2;
+
+	strDst.resize(iBytes);
+
+	for (int i=0; i != iBytes; i++)
+		strDst[i]	= (charUnHex(strSrc[i*2]) << 4) | charUnHex(strSrc[i*2+1]);
+}
+
+void DH_der_gen(std::string& strDer, int iKeyLength)
+{
+	DH*	dh	= 0;
+	int	iCodes;
+
+	do {
+		dh	= DH_generate_parameters(iKeyLength, DH_GENERATOR_5, NULL, NULL);
+		iCodes	= 0;
+		DH_check(dh, &iCodes);
+	} while (iCodes & (DH_CHECK_P_NOT_PRIME|DH_CHECK_P_NOT_SAFE_PRIME|DH_UNABLE_TO_CHECK_GENERATOR|DH_NOT_SUITABLE_GENERATOR));
+
+	strDer.resize(i2d_DHparams(dh, NULL));
+
+	unsigned char* next	= reinterpret_cast<unsigned char *>(&strDer[0]);
+
+	(void) i2d_DHparams(dh, &next);
+}
+
+void DH_der_gen_hex(std::string& strDer, int iKeyLength)
+{
+	std::string	strBuf;
+
+	DH_der_gen(strBuf, iKeyLength);
+
+	strHex(strDer, strBuf);
+}
+
+DH* DH_der_load(const std::string& strDer)
+{
+	const unsigned char *pbuf	= reinterpret_cast<const unsigned char *>(&strDer[0]);
+
+	return d2i_DHparams(NULL, &pbuf, strDer.size());
+}
+
+DH* DH_der_load_hex(const std::string& strDer)
+{
+	std::string	strBuf;
+
+	strUnHex(strBuf, strDer);
+
+	return DH_der_load(strBuf);
+}
+
 // vim:ts=4
diff --git a/src/utils.h b/src/utils.h
index dc6ba8e87..02ee67f90 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -4,6 +4,8 @@
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/format.hpp>
 
+#include <openssl/dh.h>
+
 #define nothing()   do {} while (0)
 
 boost::posix_time::ptime ptEpoch();
@@ -46,6 +48,14 @@ inline void strHex(std::string& strDst, const std::vector<unsigned char> vchData
 	strHex(strDst, vchData.begin(), vchData.size());
 }
 
+int charUnHex(char cDigit);
+void strUnHex(std::string& strDst, const std::string& strSrc);
+
+DH* DH_der_load(const std::string& strDer);
+DH* DH_der_load_hex(const std::string& strDer);
+void DH_der_gen(std::string& strDer, int iKeyLength);
+void DH_der_gen_hex(std::string& strDer, int iKeyLength);
+
 #endif
 
 // vim:ts=4