QNetworkInterface: prefer SIOCGIFINDEX over if_nametoindex

On Linux (on a bad system without getifaddrs), the ioctl for
SIOCGIFINDEX should be faster than if_nametoindex. The ioctl on the
already open socket will require one syscall, while if_nametoindex will
require at least one more (to open the socket), probably more.

Change-Id: I7de033f80b0e4431b7f1ffff13f9888bf2044105
Reviewed-by: Richard J. Moore <rich@kde.org>

diff --git a/src/network/kernel/qnetworkinterface_unix.cpp b/src/network/kernel/qnetworkinterface_unix.cpp
index 04e1ce7edd757f21666363233b067bc1e15f92c6..38cddd8f7ab139582915882945ae5f457e1b5710 100644 (file)
--- a/src/network/kernel/qnetworkinterface_unix.cpp
+++ b/src/network/kernel/qnetworkinterface_unix.cpp
@@ -185,9 +185,14 @@ static QNetworkInterfacePrivate *findInterface(int socket, QList<QNetworkInterfa
     QNetworkInterfacePrivate *iface = 0;
     int ifindex = 0;
 
-#ifndef QT_NO_IPV6IFNAME
+#if !defined(QT_NO_IPV6IFNAME) || defined(SIOCGIFINDEX)
     // Get the interface index
+#  ifdef SIOCGIFINDEX
+    if (qt_safe_ioctl(socket, SIOCGIFINDEX, &req) >= 0)
+        ifindex = req.ifr_ifindex;
+#  else
     ifindex = if_nametoindex(req.ifr_name);
+#  endif
 
     // find the interface data
     QList<QNetworkInterfacePrivate *>::Iterator if_it = interfaces.begin();