Better handling of SSL_ERROR_WANT_READ/SSL_ERROR_WANT_WRITE. Sockets on Windows platform are now non-blocking (thanks to Mehmet Bozkurt).

12 files changed, 515 insertions, 59 deletions

diff --git a/src/net/tls/gnutls/TLSSocket_GnuTLS.cpp b/src/net/tls/gnutls/TLSSocket_GnuTLS.cpp
index 35e1d415..477f655b 100644
--- a/src/net/tls/gnutls/TLSSocket_GnuTLS.cpp
+++ b/src/net/tls/gnutls/TLSSocket_GnuTLS.cpp
@@ -53,7 +53,7 @@ ref <TLSSocket> TLSSocket::wrap(ref <TLSSession> session, ref <socket> sok)
 
 TLSSocket_GnuTLS::TLSSocket_GnuTLS(ref <TLSSession_GnuTLS> session, ref <socket> sok)
 	: m_session(session), m_wrapped(sok), m_connected(false),
-	  m_handshaking(false), m_ex(NULL)
+	  m_handshaking(false), m_ex(NULL), m_status(0)
 {
 	gnutls_transport_set_ptr(*m_session->m_gnutlsSession, this);
 
@@ -131,6 +131,8 @@ void TLSSocket_GnuTLS::send(const string& buffer)
 
 TLSSocket::size_type TLSSocket_GnuTLS::receiveRaw(char* buffer, const size_type count)
 {
+	m_status &= ~STATUS_WOULDBLOCK;
+
 	const ssize_t ret = gnutls_record_recv
 		(*m_session->m_gnutlsSession,
 		 buffer, static_cast <size_t>(count));
@@ -141,23 +143,67 @@ TLSSocket::size_type TLSSocket_GnuTLS::receiveRaw(char* buffer, const size_type
 	if (ret < 0)
 	{
 		if (ret == GNUTLS_E_AGAIN)
+		{
+			m_status |= STATUS_WOULDBLOCK;
 			return 0;
+		}
 
 		TLSSession_GnuTLS::throwTLSException("gnutls_record_recv", ret);
 	}
 
-	return static_cast <int>(ret);
+	return static_cast <size_type>(ret);
 }
 
 
 void TLSSocket_GnuTLS::sendRaw(const char* buffer, const size_type count)
 {
-	gnutls_record_send
+	ssize_t ret = gnutls_record_send
+		(*m_session->m_gnutlsSession,
+		 buffer, static_cast <size_t>(count));
+
+	if (m_ex)
+		internalThrow();
+
+	if (ret < 0)
+	{
+		if (ret == GNUTLS_E_AGAIN)
+		{
+			m_status |= STATUS_WOULDBLOCK;
+			return;
+		}
+
+		TLSSession_GnuTLS::throwTLSException("gnutls_record_send", ret);
+	}
+}
+
+
+TLSSocket::size_type TLSSocket_GnuTLS::sendRawNonBlocking(const char* buffer, const size_type count)
+{
+	ssize_t ret = gnutls_record_send
 		(*m_session->m_gnutlsSession,
 		 buffer, static_cast <size_t>(count));
 
 	if (m_ex)
 		internalThrow();
+
+	if (ret < 0)
+	{
+		if (ret == GNUTLS_E_AGAIN)
+		{
+			m_status |= STATUS_WOULDBLOCK;
+			return 0;
+		}
+
+		TLSSession_GnuTLS::throwTLSException("gnutls_record_send", ret);
+	}
+
+	return static_cast <size_type>(ret);
+}
+
+
+unsigned int TLSSocket_GnuTLS::getStatus() const
+{
+	return m_status | m_wrapped->getStatus();
 }
 
 
@@ -290,8 +336,8 @@ ssize_t TLSSocket_GnuTLS::gnutlsPullFunc
 					(reinterpret_cast <char*>(data),
 					 static_cast <int>(len)));
 
-			if (n == 0)
-				return GNUTLS_E_AGAIN;  // This seems like a hack, really...
+			if (n == 0 && sok->m_wrapped->getStatus() & socket::STATUS_WOULDBLOCK)
+				return GNUTLS_E_AGAIN;
 
 			return n;
 		}
diff --git a/src/net/tls/openssl/TLSSession_OpenSSL.cpp b/src/net/tls/openssl/TLSSession_OpenSSL.cpp
index 5d7e1052..248322d4 100755
--- a/src/net/tls/openssl/TLSSession_OpenSSL.cpp
+++ b/src/net/tls/openssl/TLSSession_OpenSSL.cpp
@@ -62,6 +62,9 @@ TLSSession_OpenSSL::TLSSession_OpenSSL(ref <vmime::security::cert::certificateVe
 
 	m_sslctx = SSL_CTX_new(SSLv23_client_method());
 	SSL_CTX_set_options(m_sslctx, SSL_OP_ALL | SSL_OP_NO_SSLv2);
+	SSL_CTX_set_mode(m_sslctx, SSL_MODE_AUTO_RETRY);
+	SSL_CTX_set_cipher_list(m_sslctx, "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
+	SSL_CTX_set_session_cache_mode(m_sslctx, SSL_SESS_CACHE_OFF);
 }
 
 
diff --git a/src/net/tls/openssl/TLSSocket_OpenSSL.cpp b/src/net/tls/openssl/TLSSocket_OpenSSL.cpp
index cbd1f9fd..25937e32 100755
--- a/src/net/tls/openssl/TLSSocket_OpenSSL.cpp
+++ b/src/net/tls/openssl/TLSSocket_OpenSSL.cpp
@@ -54,7 +54,7 @@ ref <TLSSocket> TLSSocket::wrap(ref <TLSSession> session, ref <socket> sok)
 
 
 TLSSocket_OpenSSL::TLSSocket_OpenSSL(ref <TLSSession_OpenSSL> session, ref <socket> sok)
-	: m_session(session), m_wrapped(sok), m_connected(false), m_ssl(0)
+	: m_session(session), m_wrapped(sok), m_connected(false), m_ssl(0), m_ex(NULL)
 {
 }
 
@@ -162,8 +162,10 @@ TLSSocket::size_type TLSSocket_OpenSSL::getBlockSize() const
 
 void TLSSocket_OpenSSL::receive(string& buffer)
 {
-	const int size = receiveRaw(m_buffer, sizeof(m_buffer));
-	buffer = vmime::string(m_buffer, size);
+	const size_type size = receiveRaw(m_buffer, sizeof(m_buffer));
+
+	if (size >= 0)
+		buffer = vmime::string(m_buffer, size);
 }
 
 
@@ -175,19 +177,35 @@ void TLSSocket_OpenSSL::send(const string& buffer)
 
 TLSSocket::size_type TLSSocket_OpenSSL::receiveRaw(char* buffer, const size_type count)
 {
-	int rc = SSL_read(m_ssl, buffer, count);
+	int rc = SSL_read(m_ssl, buffer, static_cast <int>(count));
 	handleError(rc);
+
+	if (rc < 0)
+		return 0;
+
 	return rc;
 }
 
 
 void TLSSocket_OpenSSL::sendRaw(const char* buffer, const size_type count)
 {
-	int rc = SSL_write(m_ssl, buffer, count);
+	int rc = SSL_write(m_ssl, buffer, static_cast <int>(count));
 	handleError(rc);
 }
 
 
+TLSSocket_OpenSSL::size_type TLSSocket_OpenSSL::sendRawNonBlocking(const char* buffer, const size_type count)
+{
+	int rc = SSL_write(m_ssl, buffer, static_cast <int>(count));
+	handleError(rc);
+
+	if (rc < 0)
+		rc = 0;
+
+	return rc;
+}
+
+
 void TLSSocket_OpenSSL::handshake(ref <timeoutHandler> toHandler)
 {
 	if (toHandler)
@@ -260,6 +278,13 @@ ref <security::cert::certificateChain> TLSSocket_OpenSSL::getPeerCertificates()
 }
 
 
+void TLSSocket_OpenSSL::internalThrow()
+{
+	if (m_ex.get())
+		throw *m_ex;
+}
+
+
 void TLSSocket_OpenSSL::handleError(int rc)
 {
 	if (rc > 0) return;
@@ -277,12 +302,14 @@ void TLSSocket_OpenSSL::handleError(int rc)
 		if (lastError == 0)
 		{
 			if (rc == 0)
+			{
 				throw exceptions::tls_exception("SSL connection unexpectedly closed");
+			}
 			else
 			{
 				vmime::string msg;
 				std::ostringstream oss(msg);
-				oss << "The BIO reported an error: %d" << rc;
+				oss << "The BIO reported an error: " << rc;
 				oss.flush();
 				throw exceptions::tls_exception(oss.str());
 			}
@@ -290,10 +317,16 @@ void TLSSocket_OpenSSL::handleError(int rc)
 		break;
 	}
 
-	//// Follwoing errors should not occur
-	// With SSL_MODE_AUTO_RETRY these should not happen
 	case SSL_ERROR_WANT_READ:
+
+		BIO_set_retry_read(SSL_get_rbio(m_ssl));
+		break;
+
 	case SSL_ERROR_WANT_WRITE:
+
+		BIO_set_retry_write(SSL_get_wbio(m_ssl));
+		break;
+
 	// This happens only for BIOs of type BIO_s_connect() or BIO_s_accept()
 	case SSL_ERROR_WANT_CONNECT:
 	case SSL_ERROR_WANT_ACCEPT:
@@ -319,6 +352,12 @@ void TLSSocket_OpenSSL::handleError(int rc)
 }
 
 
+unsigned int TLSSocket_OpenSSL::getStatus() const
+{
+	return m_wrapped->getStatus();
+}
+
+
 // Implementation of custom BIO methods
 
 
@@ -330,9 +369,28 @@ int TLSSocket_OpenSSL::bio_write(BIO* bio, const char* buf, int len)
 
 	TLSSocket_OpenSSL *sok = reinterpret_cast <TLSSocket_OpenSSL*>(bio->ptr);
 
-	sok->m_wrapped->sendRaw(buf, len);
+	try
+	{
+		BIO_clear_retry_flags(bio);
+
+		const size_type n = sok->m_wrapped->sendRawNonBlocking(buf, len);
+
+		BIO_clear_retry_flags(bio);
+
+		if (n == 0 && sok->m_wrapped->getStatus() & socket::STATUS_WOULDBLOCK)
+		{
+			BIO_set_retry_write(bio);
+			return -1;
+		}
 
-	return len;
+		return static_cast <int>(len);
+	}
+	catch (exception& e)
+	{
+		// Workaround for passing C++ exceptions from C BIO functions
+		sok->m_ex.reset(e.clone());
+		return -1;
+	}
 }
 
 
@@ -344,21 +402,33 @@ int TLSSocket_OpenSSL::bio_read(BIO* bio, char* buf, int len)
 
 	TLSSocket_OpenSSL *sok = reinterpret_cast <TLSSocket_OpenSSL*>(bio->ptr);
 
-	const int n = sok->m_wrapped->receiveRaw(buf, len);
+	try
+	{
+		const size_type n = sok->m_wrapped->receiveRaw(buf, len);
 
-	if (n == 0)
-		BIO_set_retry_read(bio);  // This seems like a hack, really...
-	else
 		BIO_clear_retry_flags(bio);
 
-	return n;
+		if (sok->m_wrapped->getStatus() & socket::STATUS_WOULDBLOCK)
+		{
+			BIO_set_retry_read(bio);
+			return -1;
+		}
+
+		return static_cast <int>(n);
+	}
+	catch (exception& e)
+	{
+		// Workaround for passing C++ exceptions from C BIO functions
+		sok->m_ex.reset(e.clone());
+		return -1;
+	}
 }
 
 
 // static
 int TLSSocket_OpenSSL::bio_puts(BIO* bio, const char* str)
 {
-	return bio_write(bio, str, strlen(str));
+	return bio_write(bio, str, static_cast <int>(strlen(str)));
 }
 
 
diff --git a/src/platforms/posix/posixSocket.cpp b/src/platforms/posix/posixSocket.cpp
index 6fcbd118..b3e33f49 100644
--- a/src/platforms/posix/posixSocket.cpp
+++ b/src/platforms/posix/posixSocket.cpp
@@ -43,6 +43,13 @@
 #include "vmime/exception.hpp"
 
 
+#if defined(EWOULDBLOCK)
+#   define IS_EAGAIN(x)  ((x) == EAGAIN || (x) == EWOULDBLOCK || (x) == EINTR)
+#else
+#   define IS_EAGAIN(x)  ((x) == EAGAIN || (x) == EINTR)
+#endif
+
+
 namespace vmime {
 namespace platforms {
 namespace posix {
@@ -53,7 +60,7 @@ namespace posix {
 //
 
 posixSocket::posixSocket(ref <vmime::net::timeoutHandler> th)
-	: m_timeoutHandler(th), m_desc(-1)
+	: m_timeoutHandler(th), m_desc(-1), m_status(0)
 {
 }
 
@@ -332,13 +339,15 @@ posixSocket::size_type posixSocket::getBlockSize() const
 
 void posixSocket::receive(vmime::string& buffer)
 {
-	const int size = receiveRaw(m_buffer, sizeof(m_buffer));
+	const size_type size = receiveRaw(m_buffer, sizeof(m_buffer));
 	buffer = vmime::string(m_buffer, size);
 }
 
 
 posixSocket::size_type posixSocket::receiveRaw(char* buffer, const size_type count)
 {
+	m_status &= ~STATUS_WOULDBLOCK;
+
 	// Check whether data is available
 	fd_set fds;
 	FD_ZERO(&fds);
@@ -348,11 +357,11 @@ posixSocket::size_type posixSocket::receiveRaw(char* buffer, const size_type cou
 	tv.tv_sec = 1;
 	tv.tv_usec = 0;
 
-	int ret = ::select(m_desc + 1, &fds, NULL, NULL, &tv);
+	ssize_t ret = ::select(m_desc + 1, &fds, NULL, NULL, &tv);
 
 	if (ret < 0)
 	{
-		if (errno != EAGAIN)
+		if (!IS_EAGAIN(errno))
 			throwSocketError(errno);
 
 		// No data available at this time
@@ -372,6 +381,8 @@ posixSocket::size_type posixSocket::receiveRaw(char* buffer, const size_type cou
 			}
 		}
 
+		m_status |= STATUS_WOULDBLOCK;
+
 		// Continue waiting for data
 		return 0;
 	}
@@ -381,9 +392,27 @@ posixSocket::size_type posixSocket::receiveRaw(char* buffer, const size_type cou
 
 	if (ret < 0)
 	{
-		if (errno != EAGAIN)
+		if (!IS_EAGAIN(errno))
 			throwSocketError(errno);
 
+		// Check if we are timed out
+		if (m_timeoutHandler &&
+		    m_timeoutHandler->isTimeOut())
+		{
+			if (!m_timeoutHandler->handleTimeOut())
+			{
+				// Server did not react within timeout delay
+				throwSocketError(errno);
+			}
+			else
+			{
+				// Reset timeout
+				m_timeoutHandler->resetTimeOut();
+			}
+		}
+
+		m_status |= STATUS_WOULDBLOCK;
+
 		// No data available at this time
 		return 0;
 	}
@@ -411,15 +440,17 @@ void posixSocket::send(const vmime::string& buffer)
 
 void posixSocket::sendRaw(const char* buffer, const size_type count)
 {
+	m_status &= ~STATUS_WOULDBLOCK;
+
 	size_type size = count;
 
 	while (size > 0)
 	{
-		const int ret = ::send(m_desc, buffer, size, 0);
+		const ssize_t ret = ::send(m_desc, buffer, size, 0);
 
 		if (ret < 0)
 		{
-			if (errno != EAGAIN)
+			if (!IS_EAGAIN(errno))
 				throwSocketError(errno);
 
 			platform::getHandler()->wait();
@@ -437,6 +468,27 @@ void posixSocket::sendRaw(const char* buffer, const size_type count)
 }
 
 
+posixSocket::size_type posixSocket::sendRawNonBlocking(const char* buffer, const size_type count)
+{
+	m_status &= ~STATUS_WOULDBLOCK;
+
+	const ssize_t ret = ::send(m_desc, buffer, count, 0);
+
+	if (ret < 0)
+	{
+		if (!IS_EAGAIN(errno))
+			throwSocketError(errno);
+
+		m_status |= STATUS_WOULDBLOCK;
+
+		// No data can be written at this time
+		return 0;
+	}
+
+	return ret;
+}
+
+
 void posixSocket::throwSocketError(const int err)
 {
 	string msg;
@@ -473,6 +525,12 @@ void posixSocket::throwSocketError(const int err)
 }
 
 
+unsigned int posixSocket::getStatus() const
+{
+	return m_status;
+}
+
+
 
 //
 // posixSocketFactory
diff --git a/src/platforms/windows/windowsSocket.cpp b/src/platforms/windows/windowsSocket.cpp
index 27cbcaa7..7f58e279 100644
--- a/src/platforms/windows/windowsSocket.cpp
+++ b/src/platforms/windows/windowsSocket.cpp
@@ -40,11 +40,11 @@ namespace windows {
 
 
 //
-// posixSocket
+// windowsSocket
 //
 
 windowsSocket::windowsSocket(ref <vmime::net::timeoutHandler> th)
-	: m_timeoutHandler(th), m_desc(-1)
+	: m_timeoutHandler(th), m_desc(INVALID_SOCKET), m_status(0)
 {
 	WSAData wsaData;
 	WSAStartup(MAKEWORD(1, 1), &wsaData);
@@ -53,8 +53,9 @@ windowsSocket::windowsSocket(ref <vmime::net::timeoutHandler> th)
 
 windowsSocket::~windowsSocket()
 {
-	if (m_desc != -1)
+	if (m_desc != INVALID_SOCKET)
 		::closesocket(m_desc);
+
 	WSACleanup();
 }
 
@@ -62,10 +63,10 @@ windowsSocket::~windowsSocket()
 void windowsSocket::connect(const vmime::string& address, const vmime::port_t port)
 {
 	// Close current connection, if any
-	if (m_desc != -1)
+	if (m_desc != INVALID_SOCKET)
 	{
 		::closesocket(m_desc);
-		m_desc = -1;
+		m_desc = INVALID_SOCKET;
 	}
 
 	// Resolve address
@@ -93,35 +94,64 @@ void windowsSocket::connect(const vmime::string& address, const vmime::port_t po
 	// Get a new socket
 	m_desc = ::socket(AF_INET, SOCK_STREAM, 0);
 
-	if (m_desc == -1)
-		throw vmime::exceptions::connection_error("Error while creating socket.");
+	if (m_desc == INVALID_SOCKET)
+	{
+		try
+		{
+			int err = WSAGetLastError();
+			throwSocketError(err);
+		}
+		catch (exceptions::socket_exception& e)
+		{
+			throw vmime::exceptions::connection_error
+				("Error while creating socket.", e);
+		}
+	}
 
 	// Start connection
 	if (::connect(m_desc, reinterpret_cast <sockaddr*>(&addr), sizeof(addr)) == -1)
 	{
-		::closesocket(m_desc);
-		m_desc = -1;
+		try
+		{
+			int err = WSAGetLastError();
+			throwSocketError(err);
+		}
+		catch (exceptions::socket_exception& e)
+		{
+			::closesocket(m_desc);
+			m_desc = INVALID_SOCKET;
 
-		// Error
-		throw vmime::exceptions::connection_error("Error while connecting socket.");
+			// Error
+			throw vmime::exceptions::connection_error
+				("Error while connecting socket.", e);
+		}
 	}
+
+	// Set socket to non-blocking
+	unsigned long non_blocking = 1;
+	::ioctlsocket(m_desc, FIONBIO, &non_blocking);
 }
 
 
 bool windowsSocket::isConnected() const
 {
-	return (m_desc != -1);
+	if (m_desc == INVALID_SOCKET)
+		return false;
+
+	char buff;
+
+	return ::recv(m_desc, &buff, 1, MSG_PEEK) != 0;
 }
 
 
 void windowsSocket::disconnect()
 {
-	if (m_desc != -1)
+	if (m_desc != INVALID_SOCKET)
 	{
 		::shutdown(m_desc, SD_BOTH);
 		::closesocket(m_desc);
 
-		m_desc = -1;
+		m_desc = INVALID_SOCKET;
 	}
 }
 
@@ -134,48 +164,200 @@ windowsSocket::size_type windowsSocket::getBlockSize() const
 
 void windowsSocket::receive(vmime::string& buffer)
 {
-	int ret = ::recv(m_desc, m_buffer, sizeof(m_buffer), 0);
-
-	if (ret == -1)
-	{
-		// Error or no data
-		return;
-	}
-	else if (ret > 0)
-	{
-		buffer = vmime::string(m_buffer, ret);
-	}
+	const size_type size = receiveRaw(m_buffer, sizeof(m_buffer));
+	buffer = vmime::string(m_buffer, size);
 }
 
 
 windowsSocket::size_type windowsSocket::receiveRaw(char* buffer, const size_type count)
 {
+	m_status &= ~STATUS_WOULDBLOCK;
+
+	// Check whether data is available
+	bool timedout;
+	waitForData(READ, timedout);
+
+	if (timedout)
+	{
+		// No data available at this time
+		// Check if we are timed out
+		if (m_timeoutHandler &&
+		    m_timeoutHandler->isTimeOut())
+		{
+			if (!m_timeoutHandler->handleTimeOut())
+			{
+				// Server did not react within timeout delay
+				throwSocketError(WSAETIMEDOUT);
+			}
+			else
+			{
+				// Reset timeout
+				m_timeoutHandler->resetTimeOut();
+			}
+		}
+
+		// Continue waiting for data
+		return 0;
+	}
+
+	// Read available data
 	int ret = ::recv(m_desc, buffer, count, 0);
 
-	if (ret == -1)
+	if (ret == SOCKET_ERROR)
 	{
+		int err = WSAGetLastError();
+
+		if (err != WSAEWOULDBLOCK)
+			throwSocketError(err);
+
+		m_status |= STATUS_WOULDBLOCK;
+
 		// Error or no data
 		return (0);
 	}
+	else if (ret == 0)
+	{
+		// Host shutdown
+		throwSocketError(WSAENOTCONN);
+	}
 	else
 	{
-		return (ret);
+		// Data received, reset timeout
+		if (m_timeoutHandler)
+			m_timeoutHandler->resetTimeOut();
+
+		return ret;
 	}
 }
 
 
 void windowsSocket::send(const vmime::string& buffer)
 {
-	::send(m_desc, buffer.data(), buffer.length(), 0);
+	sendRaw(buffer.data(), buffer.length());
 }
 
 
 void windowsSocket::sendRaw(const char* buffer, const size_type count)
 {
-	::send(m_desc, buffer, count, 0);
+	m_status &= ~STATUS_WOULDBLOCK;
+
+	size_type size = count;
+
+	while (size > 0)
+	{
+		const int ret = ::send(m_desc, buffer, size, 0);
+
+		if (ret == SOCKET_ERROR)
+		{
+			int err = WSAGetLastError();
+
+			if (err != WSAEWOULDBLOCK)
+				throwSocketError(err);
+
+			bool timedout;
+			waitForData(WRITE, timedout);
+		}
+		else
+		{
+			buffer += ret;
+			size -= ret;
+		}
+	}
+
+	// Reset timeout
+	if (m_timeoutHandler)
+		m_timeoutHandler->resetTimeOut();
+}
+
+
+windowsSocket::size_type windowsSocket::sendRawNonBlocking(const char* buffer, const size_type count, const bool block)
+{
+	m_status &= ~STATUS_WOULDBLOCK;
+
+	const int ret = ::send(m_desc, buffer, count, 0);
+
+	if (ret == SOCKET_ERROR)
+	{
+		int err = WSAGetLastError();
+
+		if (err == WSAEWOULDBLOCK)
+		{
+			m_status |= STATUS_WOULDBLOCK;
+
+			// No data can be written at this time
+			return 0;
+		}
+		else
+		{
+			throwSocketError(err);
+		}
+	}
+
+	return ret;
 }
 
 
+unsigned int windowsSocket::getStatus() const
+{
+	return m_status;
+}
+
+
+void windowsSocket::throwSocketError(const int err)
+{
+	std::ostringstream oss;
+	string msg;
+
+	LPTSTR str;
+
+	if (::FormatMessage(
+			FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
+			NULL, err, 0, (LPTSTR) &str, 0, NULL) == 0)
+	{
+		// Failed getting message
+		oss << "Unknown socket error (code " << err << ")";
+	}
+	else
+	{
+		oss << str;
+		::LocalFree(str);
+	}
+
+	msg = oss.str();
+
+	throw exceptions::socket_exception(msg);
+}
+
+
+void windowsSocket::waitForData(const WaitOpType t, bool& timedOut)
+{
+	// Check whether data is available
+	fd_set fds;
+	FD_ZERO(&fds);
+	FD_SET(m_desc, &fds);
+
+	struct timeval tv;
+	tv.tv_sec = 1;
+	tv.tv_usec = 0;
+
+	int ret;
+
+	if (t & READ)
+		ret = ::select(m_desc + 1, &fds, NULL, NULL, &tv);
+	else if (t & WRITE)
+		ret = ::select(m_desc + 1, NULL, &fds, NULL, &tv);
+	else
+		ret = ::select(m_desc + 1, &fds, &fds, NULL, &tv);
+
+	timedOut = (ret == 0);
+
+	if (ret == SOCKET_ERROR)
+	{
+		int err = WSAGetLastError();
+		throwSocketError(err);
+	}
+}
+
 
 
 //
diff --git a/src/security/sasl/SASLSocket.cpp b/src/security/sasl/SASLSocket.cpp
index 28f5f6f6..531e4188 100644
--- a/src/security/sasl/SASLSocket.cpp
+++ b/src/security/sasl/SASLSocket.cpp
@@ -177,6 +177,40 @@ void SASLSocket::sendRaw(const char* buffer, const size_type count)
 }
 
 
+SASLSocket::size_type SASLSocket::sendRawNonBlocking(const char* buffer, const size_type count)
+{
+	byte_t* output = 0;
+	int outputLen = 0;
+
+	m_session->getMechanism()->encode
+		(m_session, reinterpret_cast <const byte_t*>(buffer), count,
+		 &output, &outputLen);
+
+	size_type bytesSent = 0;
+
+	try
+	{
+		bytesSent = m_wrapped->sendRawNonBlocking
+			(reinterpret_cast <const char*>(output), outputLen);
+	}
+	catch (...)
+	{
+		delete [] output;
+		throw;
+	}
+
+	delete [] output;
+
+	return bytesSent;
+}
+
+
+unsigned int SASLSocket::getStatus() const
+{
+	return m_wrapped->getStatus();
+}
+
+
 } // sasl
 } // security
 } // vmime
diff --git a/vmime/net/socket.hpp b/vmime/net/socket.hpp
index 0fac6514..4551e3e2 100644
--- a/vmime/net/socket.hpp
+++ b/vmime/net/socket.hpp
@@ -47,11 +47,17 @@ class socket : public object
 {
 public:
 
+	enum Status
+	{
+		STATUS_WOULDBLOCK = 0x1   /**< The receive operation would block. */
+	};
+
+
 	virtual ~socket() { }
 
 	/** Type used for lengths in streams.
 	  */
-	typedef int size_type;
+	typedef long size_type;
 
 
 	/** Connect to the specified address and port.
@@ -84,7 +90,7 @@ public:
 	  * @param count maximum number of bytes to receive (size of buffer)
 	  * @return number of bytes received/written into output buffer
 	  */
-	virtual int receiveRaw(char* buffer, const size_type count) = 0;
+	virtual size_type receiveRaw(char* buffer, const size_type count) = 0;
 
 	/** Send (text) data to the socket.
 	  *
@@ -99,6 +105,15 @@ public:
 	  */
 	virtual void sendRaw(const char* buffer, const size_type count) = 0;
 
+	/** Send (raw) data to the socket.
+	  * Function may returns before all data is sent.
+	  *
+	  * @param buffer data to send
+	  * @param count number of bytes to send (size of buffer)
+	  * @return number of bytes sent
+	  */
+	virtual size_type sendRawNonBlocking(const char* buffer, const size_type count) = 0;
+
 	/** Return the preferred maximum block size when reading
 	  * from or writing to this stream.
 	  *
@@ -106,6 +121,12 @@ public:
 	  */
 	virtual size_type getBlockSize() const = 0;
 
+	/** Return the current status of this socket.
+	  *
+	  * @return status flags for this socket
+	  */
+	virtual unsigned int getStatus() const = 0;
+
 protected:
 
 	socket() { }
diff --git a/vmime/net/tls/gnutls/TLSSocket_GnuTLS.hpp b/vmime/net/tls/gnutls/TLSSocket_GnuTLS.hpp
index 729923f3..ca113f17 100644
--- a/vmime/net/tls/gnutls/TLSSocket_GnuTLS.hpp
+++ b/vmime/net/tls/gnutls/TLSSocket_GnuTLS.hpp
@@ -70,9 +70,12 @@ public:
 
 	void send(const string& buffer);
 	void sendRaw(const char* buffer, const size_type count);
+	size_type sendRawNonBlocking(const char* buffer, const size_type count);
 
 	size_type getBlockSize() const;
 
+	unsigned int getStatus() const;
+
 private:
 
 	void internalThrow();
@@ -97,6 +100,8 @@ private:
 	ref <timeoutHandler> m_toHandler;
 
 	exception* m_ex;
+
+	unsigned int m_status;
 };
 
 
diff --git a/vmime/net/tls/openssl/TLSSocket_OpenSSL.hpp b/vmime/net/tls/openssl/TLSSocket_OpenSSL.hpp
index 401fad12..ab4093f7 100755
--- a/vmime/net/tls/openssl/TLSSocket_OpenSSL.hpp
+++ b/vmime/net/tls/openssl/TLSSocket_OpenSSL.hpp
@@ -36,6 +36,8 @@
 
 #include "vmime/net/tls/TLSSocket.hpp"
 
+#include <memory>
+
 #include <openssl/ssl.h>
 
 
@@ -72,9 +74,12 @@ public:
 
 	void send(const string& buffer);
 	void sendRaw(const char* buffer, const size_type count);
+	size_type sendRawNonBlocking(const char* buffer, const size_type count);
 
 	size_type getBlockSize() const;
 
+	unsigned int getStatus() const;
+
 private:
 
 	static int bio_write(BIO* bio, const char* buf, int len);
@@ -87,8 +92,10 @@ private:
 
 	void createSSLHandle();
 
+	void internalThrow();
 	void handleError(int rc);
 
+
 	ref <TLSSession_OpenSSL> m_session;
 
 	ref <socket> m_wrapped;
@@ -100,6 +107,9 @@ private:
 	ref <timeoutHandler> m_toHandler;
 
 	SSL* m_ssl;
+
+	// Last exception thrown from C BIO functions
+	std::auto_ptr <std::exception> m_ex;
 };
 
 
diff --git a/vmime/platforms/posix/posixSocket.hpp b/vmime/platforms/posix/posixSocket.hpp
index 1332505b..78b1c0aa 100644
--- a/vmime/platforms/posix/posixSocket.hpp
+++ b/vmime/platforms/posix/posixSocket.hpp
@@ -55,9 +55,12 @@ public:
 
 	void send(const vmime::string& buffer);
 	void sendRaw(const char* buffer, const size_type count);
+	size_type sendRawNonBlocking(const char* buffer, const size_type count);
 
 	size_type getBlockSize() const;
 
+	unsigned int getStatus() const;
+
 protected:
 
 	static void throwSocketError(const int err);
@@ -68,6 +71,8 @@ private:
 
 	char m_buffer[65536];
 	int m_desc;
+
+	unsigned int m_status;
 };
 
 
diff --git a/vmime/platforms/windows/windowsSocket.hpp b/vmime/platforms/windows/windowsSocket.hpp
index c41d8bfe..ca007a06 100644
--- a/vmime/platforms/windows/windowsSocket.hpp
+++ b/vmime/platforms/windows/windowsSocket.hpp
@@ -43,6 +43,7 @@ namespace windows {
 class windowsSocket : public vmime::net::socket
 {
 public:
+
 	windowsSocket();
 	windowsSocket(ref <vmime::net::timeoutHandler> th);
 	~windowsSocket();
@@ -58,15 +59,33 @@ public:
 
 	void send(const vmime::string& buffer);
 	void sendRaw(const char* buffer, const size_type count);
+	size_type sendRawNonBlocking(const char* buffer, const size_type count);
 
 	size_type getBlockSize() const;
 
+	unsigned int getStatus() const;
+
+protected:
+
+	void throwSocketError(const int err);
+
+	enum WaitOpType
+	{
+		READ  = 1,
+		WRITE = 2,
+		BOTH  = 4
+	};
+
+	void waitForData(const WaitOpType t, bool& timedOut);
+
 private:
 
 	ref <vmime::net::timeoutHandler> m_timeoutHandler;
 
 	char m_buffer[65536];
 	SOCKET m_desc;
+
+	unsigned int m_status;
 };
 
 
diff --git a/vmime/security/sasl/SASLSocket.hpp b/vmime/security/sasl/SASLSocket.hpp
index f05ed424..d6f4ecd9 100644
--- a/vmime/security/sasl/SASLSocket.hpp
+++ b/vmime/security/sasl/SASLSocket.hpp
@@ -63,9 +63,12 @@ public:
 
 	void send(const string& buffer);
 	void sendRaw(const char* buffer, const size_type count);
+	size_type sendRawNonBlocking(const char* buffer, const size_type count);
 
 	size_type getBlockSize() const;
 
+	unsigned int getStatus() const;
+
 private:
 
 	ref <SASLSession> m_session;