From 94b29782eb84ed6471f41399756b5f7a1aebfded Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Tue, 1 Apr 2014 14:19:07 -0700
Subject: [PATCH] re-scaffold some client side DTLS in DTLSSession

---
 libraries/shared/src/DTLSSession.cpp   | 50 +++++++++++++++++++-------
 libraries/shared/src/DTLSSession.h     | 15 ++++----
 libraries/shared/src/DomainHandler.cpp |  3 +-
 3 files changed, 46 insertions(+), 22 deletions(-)

diff --git a/libraries/shared/src/DTLSSession.cpp b/libraries/shared/src/DTLSSession.cpp
index ce14d91f27..9c86f8d7a2 100644
--- a/libraries/shared/src/DTLSSession.cpp
+++ b/libraries/shared/src/DTLSSession.cpp
@@ -6,13 +6,15 @@
 //  Copyright (c) 2014 High Fidelity, Inc. All rights reserved.
 //
 
+#include <gnutls/dtls.h>
+
 #include "DTLSSession.h"
 
-static int socketPullTimeout(gnutls_transport_ptr_t ptr, unsigned int ms) {
+int DTLSSession::socketPullTimeout(gnutls_transport_ptr_t ptr, unsigned int ms) {
     return 1;
 }
 
-static ssize_t socketPull(gnutls_transport_ptr_t ptr, void* buffer, size_t size) {
+ssize_t DTLSSession::socketPull(gnutls_transport_ptr_t ptr, void* buffer, size_t size) {
     DTLSSession* session = static_cast<DTLSSession*>(ptr);
     QUdpSocket& dtlsSocket = session->_dtlsSocket;
     
@@ -24,20 +26,44 @@ static ssize_t socketPull(gnutls_transport_ptr_t ptr, void* buffer, size_t size)
     }
 }
 
-static ssize_t socketPush(gnutls_transport_ptr_t ptr, const void* buffer, size_t size) {
+ssize_t DTLSSession::socketPush(gnutls_transport_ptr_t ptr, const void* buffer, size_t size) {
     DTLSSession* session = static_cast<DTLSSession*>(ptr);
     QUdpSocket& dtlsSocket = session->_dtlsSocket;
     
-    if (dtlsSocket.state() != QAbstractSocket::ConnectedState) {
-        gnutls_transport_set_errno(session->_gnutlsSession, GNUTLS_E_AGAIN);
-        return -1;
-    }
-    
-    return dtlsSocket.write(reinterpret_cast<const char*>(buffer), size);
+    return dtlsSocket.writeDatagram(reinterpret_cast<const char*>(buffer), size,
+                                    session->_destinationSocket.getAddress(), session->_destinationSocket.getPort());
 }
 
-DTLSSession::DTLSSession(QUdpSocket& dtlsSocket) :
-    _dtlsSocket(dtlsSocket)
-{
+static gnutls_certificate_credentials_t* x509ClientCredentials() {
+    static gnutls_certificate_credentials_t x509Credentials;
+    static bool credentialsInitialized = false;
     
+    if (!credentialsInitialized) {
+        gnutls_certificate_allocate_credentials(&x509Credentials);
+    }
+    
+    return &x509Credentials;
+}
+
+DTLSSession::DTLSSession(QUdpSocket& dtlsSocket, HifiSockAddr& destinationSocket) :
+    _dtlsSocket(dtlsSocket),
+    _destinationSocket(destinationSocket)
+{
+    qDebug() << "Initializing DTLS Session.";
+    
+    gnutls_init(&_gnutlsSession, GNUTLS_CLIENT | GNUTLS_DATAGRAM);
+    gnutls_priority_set_direct(_gnutlsSession, "NORMAL", NULL);
+    
+    gnutls_credentials_set(_gnutlsSession, GNUTLS_CRD_CERTIFICATE, x509ClientCredentials());
+    
+    // tell GnuTLS to call us for push or pull
+    gnutls_transport_set_ptr(_gnutlsSession, this);
+    gnutls_transport_set_push_function(_gnutlsSession, socketPush);
+    gnutls_transport_set_pull_function(_gnutlsSession, socketPull);
+    gnutls_transport_set_pull_timeout_function(_gnutlsSession, socketPullTimeout);
+    
+    // start the handshake process with domain-server now
+    int handshakeReturn = gnutls_handshake(_gnutlsSession);
+    gnutls_perror(handshakeReturn);
+    qDebug() << "HR" << handshakeReturn;
 }
\ No newline at end of file
diff --git a/libraries/shared/src/DTLSSession.h b/libraries/shared/src/DTLSSession.h
index 190373c155..c0077a38b4 100644
--- a/libraries/shared/src/DTLSSession.h
+++ b/libraries/shared/src/DTLSSession.h
@@ -13,20 +13,19 @@
 
 #include <gnutls/gnutls.h>
 
-static int socketPullTimeout(gnutls_transport_ptr_t ptr, unsigned int ms);
-static ssize_t socketPull(gnutls_transport_ptr_t ptr, void* buffer, size_t size);
-static ssize_t socketPush(gnutls_transport_ptr_t ptr, const void* buffer, size_t size);
+#include "HifiSockAddr.h"
 
 class DTLSSession {
 public:
-    DTLSSession(QUdpSocket& dtlsSocket);
-    
-    friend int socketPullTimeout(gnutls_transport_ptr_t ptr, unsigned int ms);
-    friend ssize_t socketPull(gnutls_transport_ptr_t ptr, void* buffer, size_t size);
-    friend ssize_t socketPush(gnutls_transport_ptr_t ptr, const void* buffer, size_t size);    
+    DTLSSession(QUdpSocket& dtlsSocket, HifiSockAddr& destinationSocket);
 private:
+    static int socketPullTimeout(gnutls_transport_ptr_t ptr, unsigned int ms);
+    static ssize_t socketPull(gnutls_transport_ptr_t ptr, void* buffer, size_t size);
+    static ssize_t socketPush(gnutls_transport_ptr_t ptr, const void* buffer, size_t size);
+    
     QUdpSocket& _dtlsSocket;
     gnutls_session_t _gnutlsSession;
+    HifiSockAddr _destinationSocket;
 };
 
 #endif /* defined(__hifi__DTLSSession__) */
diff --git a/libraries/shared/src/DomainHandler.cpp b/libraries/shared/src/DomainHandler.cpp
index 52bfa04414..2881da64c5 100644
--- a/libraries/shared/src/DomainHandler.cpp
+++ b/libraries/shared/src/DomainHandler.cpp
@@ -42,7 +42,7 @@ void DomainHandler::reset() {
 
 void DomainHandler::initializeDTLSSession() {
     if (!_dtlsSession) {
-        _dtlsSession = new DTLSSession(NodeList::getInstance()->getDTLSSocket());
+        _dtlsSession = new DTLSSession(NodeList::getInstance()->getDTLSSocket(), _sockAddr);
     }
 }
 
@@ -119,7 +119,6 @@ void DomainHandler::parseDTLSRequirementPacket(const QByteArray& dtlsRequirement
     unsigned short dtlsPort = 0;
     memcpy(&dtlsPort, dtlsRequirementPacket.data() + numBytesPacketHeader, sizeof(dtlsPort));
     
-    
     qDebug() << "domain-server DTLS port changed to" << dtlsPort << "- Enabling DTLS.";
     
     _sockAddr.setPort(dtlsPort);