Sockets: Added support for SO_KEEPALIVE and TCP_NODELAY

Introduce QAbstractSocket::setSocketOption that allows
to set the socket options for TCP Keep Alive and
TCP_NODELAY (disabling Nagle's Algorithm).

Reviewed-by: Thiago

8 files changed, 154 insertions, 10 deletions

diff --git a/src/network/socket/qabstractsocket.cpp b/src/network/socket/qabstractsocket.cpp
index d099382a62..be90b96456 100644
--- a/src/network/socket/qabstractsocket.cpp
+++ b/src/network/socket/qabstractsocket.cpp
@@ -332,6 +332,22 @@
     \sa QAbstractSocket::state()
 */
 
+/*!
+    \enum QAbstractSocket::SocketOption
+    \since 4.6
+
+    This enum represents the options that can be set on a socket.
+    If desired, they can be set after having received the connected() signal from
+    the socket or after having received a new socket from a QTcpServer.
+
+    \value LowDelayOption Try to optimize the socket for low latency. For a QTcpSocket
+    this would set the TCP_NODELAY option and disable Nagle's algorithm. Set this to 1
+    to enable.
+    \value KeepAliveOption Set this to 1 to enable the SO_KEEPALIVE socket option
+
+    \sa QAbstractSocket::setSocketOption(), QAbstractSocket::socketOption()
+*/
+
 #include "qabstractsocket.h"
 #include "qabstractsocket_p.h"
 
@@ -1548,6 +1564,54 @@ bool QAbstractSocket::setSocketDescriptor(int socketDescriptor, SocketState sock
     return true;
 }
 
+/*!
+    Sets the option \a option to the value described by \a value.
+
+    \sa socketOption()
+*/
+void QAbstractSocket::setSocketOption(QAbstractSocket::SocketOption option, QVariant value)
+{
+    if (!d_func()->socketEngine)
+        return;
+
+    switch (option) {
+        case LowDelayOption:
+            d_func()->socketEngine->setOption(QAbstractSocketEngine::LowDelayOption, value.toInt());
+            break;
+
+        case KeepAliveOption:
+            d_func()->socketEngine->setOption(QAbstractSocketEngine::KeepAliveOption, value.toInt());
+            break;
+    }
+}
+
+/*!
+    Returns the value of the \a option option.
+
+    \sa setSocketOption()
+*/
+QVariant QAbstractSocket::socketOption(QAbstractSocket::SocketOption option)
+{
+    if (!d_func()->socketEngine)
+        return QVariant();
+
+    int ret = -1;
+    switch (option) {
+        case LowDelayOption:
+            ret = d_func()->socketEngine->option(QAbstractSocketEngine::LowDelayOption);
+            break;
+
+        case KeepAliveOption:
+            ret = d_func()->socketEngine->option(QAbstractSocketEngine::KeepAliveOption);
+            break;
+    }
+    if (ret == -1)
+        return QVariant();
+    else
+        return QVariant(ret);
+}
+
+
 /*
    Returns the difference between msecs and elapsed. If msecs is -1,
    however, -1 is returned.
diff --git a/src/network/socket/qabstractsocket.h b/src/network/socket/qabstractsocket.h
index ed187e54eb..50a38bb7a6 100644
--- a/src/network/socket/qabstractsocket.h
+++ b/src/network/socket/qabstractsocket.h
@@ -116,6 +116,10 @@ public:
         Connection = ConnectedState
 #endif
     };
+    enum SocketOption {
+        LowDelayOption, // TCP_NODELAY
+        KeepAliveOption // SO_KEEPALIVE
+    };
 
     QAbstractSocket(SocketType socketType, QObject *parent);
     virtual ~QAbstractSocket();
@@ -149,6 +153,10 @@ public:
     bool setSocketDescriptor(int socketDescriptor, SocketState state = ConnectedState,
                              OpenMode openMode = ReadWrite);
 
+    // ### Qt 5: Make virtual?
+    void setSocketOption(QAbstractSocket::SocketOption o, QVariant v);
+    QVariant socketOption(QAbstractSocket::SocketOption o);
+
     SocketType socketType() const;
     SocketState state() const;
     SocketError error() const;
diff --git a/src/network/socket/qabstractsocketengine_p.h b/src/network/socket/qabstractsocketengine_p.h
index b784f65854..39c00cc15c 100644
--- a/src/network/socket/qabstractsocketengine_p.h
+++ b/src/network/socket/qabstractsocketengine_p.h
@@ -92,7 +92,9 @@ public:
         SendBufferSocketOption,
         AddressReusable,
         BindExclusively,
-        ReceiveOutOfBandData
+        ReceiveOutOfBandData,
+        LowDelayOption,
+        KeepAliveOption
     };
 
     virtual bool initialize(QAbstractSocket::SocketType type, QAbstractSocket::NetworkLayerProtocol protocol = QAbstractSocket::IPv4Protocol) = 0;
diff --git a/src/network/socket/qhttpsocketengine.cpp b/src/network/socket/qhttpsocketengine.cpp
index 156a9f4b80..84b7c1403d 100644
--- a/src/network/socket/qhttpsocketengine.cpp
+++ b/src/network/socket/qhttpsocketengine.cpp
@@ -276,13 +276,30 @@ qint64 QHttpSocketEngine::pendingDatagramSize() const
 }
 #endif // QT_NO_UDPSOCKET
 
-int QHttpSocketEngine::option(SocketOption) const
+int QHttpSocketEngine::option(SocketOption option) const
 {
+    Q_D(const QHttpSocketEngine);
+    if (d->socket) {
+        // convert the enum and call the real socket
+        if (option == QAbstractSocketEngine::LowDelayOption)
+            return d->socket->socketOption(QAbstractSocket::LowDelayOption).toInt();
+        if (option == QAbstractSocketEngine::KeepAliveOption)
+            return d->socket->socketOption(QAbstractSocket::KeepAliveOption).toInt();
+    }
     return -1;
 }
 
-bool QHttpSocketEngine::setOption(SocketOption, int)
+bool QHttpSocketEngine::setOption(SocketOption option, int value)
 {
+    Q_D(QHttpSocketEngine);
+    if (d->socket) {
+        // convert the enum and call the real socket
+        if (option == QAbstractSocketEngine::LowDelayOption)
+            d->socket->setSocketOption(QAbstractSocket::LowDelayOption, value);
+        if (option == QAbstractSocketEngine::KeepAliveOption)
+            d->socket->setSocketOption(QAbstractSocket::KeepAliveOption, value);
+        return true;
+    }
     return false;
 }
 
diff --git a/src/network/socket/qnativesocketengine_unix.cpp b/src/network/socket/qnativesocketengine_unix.cpp
index 3991ae61c1..b4b673a4ec 100644
--- a/src/network/socket/qnativesocketengine_unix.cpp
+++ b/src/network/socket/qnativesocketengine_unix.cpp
@@ -65,6 +65,8 @@
 #include <ctype.h>
 #endif
 
+#include <netinet/tcp.h>
+
 QT_BEGIN_NAMESPACE
 
 #if defined QNATIVESOCKETENGINE_DEBUG
@@ -203,6 +205,8 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
         return -1;
 
     int n = -1;
+    int level = SOL_SOCKET; // default
+
     switch (opt) {
     case QNativeSocketEngine::ReceiveBufferSocketOption:
         n = SO_RCVBUF;
@@ -222,11 +226,18 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
     case QNativeSocketEngine::ReceiveOutOfBandData:
         n = SO_OOBINLINE;
         break;
+    case QNativeSocketEngine::LowDelayOption:
+        level = IPPROTO_TCP;
+        n = TCP_NODELAY;
+        break;
+    case QNativeSocketEngine::KeepAliveOption:
+        n = SO_KEEPALIVE;
+        break;
     }
 
     int v = -1;
     QT_SOCKOPTLEN_T len = sizeof(v);
-    if (getsockopt(socketDescriptor, SOL_SOCKET, n, (char *) &v, &len) != -1)
+    if (getsockopt(socketDescriptor, level, n, (char *) &v, &len) != -1)
         return v;
     return -1;
 }
@@ -242,6 +253,8 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
         return false;
 
     int n = 0;
+    int level = SOL_SOCKET; // default
+
     switch (opt) {
     case QNativeSocketEngine::ReceiveBufferSocketOption:
         n = SO_RCVBUF;
@@ -282,9 +295,16 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
     case QNativeSocketEngine::ReceiveOutOfBandData:
         n = SO_OOBINLINE;
         break;
+    case QNativeSocketEngine::LowDelayOption:
+        level = IPPROTO_TCP;
+        n = TCP_NODELAY;
+        break;
+    case QNativeSocketEngine::KeepAliveOption:
+        n = SO_KEEPALIVE;
+        break;
     }
 
-    return ::setsockopt(socketDescriptor, SOL_SOCKET, n, (char *) &v, sizeof(v)) == 0;
+    return ::setsockopt(socketDescriptor, level, n, (char *) &v, sizeof(v)) == 0;
 }
 
 bool QNativeSocketEnginePrivate::nativeConnect(const QHostAddress &addr, quint16 port)
diff --git a/src/network/socket/qnativesocketengine_win.cpp b/src/network/socket/qnativesocketengine_win.cpp
index 6bc23ceb7d..f0b9f0bd9b 100644
--- a/src/network/socket/qnativesocketengine_win.cpp
+++ b/src/network/socket/qnativesocketengine_win.cpp
@@ -362,6 +362,8 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
         return -1;
 
     int n = -1;
+    int level = SOL_SOCKET; // default
+
     switch (opt) {
     case QNativeSocketEngine::ReceiveBufferSocketOption:
         n = SO_RCVBUF;
@@ -389,11 +391,18 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
     case QNativeSocketEngine::ReceiveOutOfBandData:
         n = SO_OOBINLINE;
         break;
+    case QNativeSocketEngine::LowDelayOption:
+        level = IPPROTO_TCP;
+        n = TCP_NODELAY;
+        break;
+    case QNativeSocketEngine::KeepAliveOption:
+        n = SO_KEEPALIVE;
+        break;
     }
 
     int v = -1;
     QT_SOCKOPTLEN_T len = sizeof(v);
-    if (getsockopt(socketDescriptor, SOL_SOCKET, n, (char *) &v, &len) != -1)
+    if (getsockopt(socketDescriptor, level, n, (char *) &v, &len) != -1)
         return v;
     return -1;
 }
@@ -409,6 +418,8 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
         return false;
 
     int n = 0;
+    int level = SOL_SOCKET; // default
+
     switch (opt) {
     case QNativeSocketEngine::ReceiveBufferSocketOption:
         n = SO_RCVBUF;
@@ -440,9 +451,16 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
     case QNativeSocketEngine::ReceiveOutOfBandData:
         n = SO_OOBINLINE;
         break;
+    case QNativeSocketEngine::LowDelayOption:
+        level = IPPROTO_TCP;
+        n = TCP_NODELAY;
+        break;
+    case QNativeSocketEngine::KeepAliveOption:
+        n = SO_KEEPALIVE;
+        break;
     }
 
-    if (::setsockopt(socketDescriptor, SOL_SOCKET, n, (char*)&v, sizeof(v)) != 0) {
+    if (::setsockopt(socketDescriptor, level, n, (char*)&v, sizeof(v)) != 0) {
         WS_ERROR_DEBUG(WSAGetLastError());
         return false;
     }
diff --git a/src/network/socket/qsocks5socketengine.cpp b/src/network/socket/qsocks5socketengine.cpp
index c9e5150894..d226f21da5 100644
--- a/src/network/socket/qsocks5socketengine.cpp
+++ b/src/network/socket/qsocks5socketengine.cpp
@@ -1621,14 +1621,28 @@ qint64 QSocks5SocketEngine::pendingDatagramSize() const
 
 int QSocks5SocketEngine::option(SocketOption option) const
 {
-    Q_UNUSED(option);
+    Q_D(const QSocks5SocketEngine);
+    if (d->data && d->data->controlSocket) {
+        // convert the enum and call the real socket
+        if (option == QAbstractSocketEngine::LowDelayOption)
+            return d->data->controlSocket->socketOption(QAbstractSocket::LowDelayOption).toInt();
+        if (option == QAbstractSocketEngine::KeepAliveOption)
+            return d->data->controlSocket->socketOption(QAbstractSocket::KeepAliveOption).toInt();
+    }
     return -1;
 }
 
 bool QSocks5SocketEngine::setOption(SocketOption option, int value)
 {
-    Q_UNUSED(option);
-    Q_UNUSED(value);
+    Q_D(QSocks5SocketEngine);
+    if (d->data && d->data->controlSocket) {
+        // convert the enum and call the real socket
+        if (option == QAbstractSocketEngine::LowDelayOption)
+            d->data->controlSocket->setSocketOption(QAbstractSocket::LowDelayOption, value);
+        if (option == QAbstractSocketEngine::KeepAliveOption)
+            d->data->controlSocket->setSocketOption(QAbstractSocket::KeepAliveOption, value);
+        return true;
+    }
     return false;
 }
 
diff --git a/src/network/socket/qtcpsocket.h b/src/network/socket/qtcpsocket.h
index 81f81dea9c..4e1003ab7b 100644
--- a/src/network/socket/qtcpsocket.h
+++ b/src/network/socket/qtcpsocket.h
@@ -43,6 +43,7 @@
 #define QTCPSOCKET_H
 
 #include <QtNetwork/qabstractsocket.h>
+#include <QtCore/qvariant.h>
 
 QT_BEGIN_HEADER