From 1bf9cb44e24ba2d795e3c242276d07acb0e46322 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Tue, 11 Aug 2015 15:21:30 -0700
Subject: [PATCH] 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>
---
 src/network/kernel/qnetworkinterface_unix.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/network/kernel/qnetworkinterface_unix.cpp b/src/network/kernel/qnetworkinterface_unix.cpp
index 04e1ce7edd..38cddd8f7a 100644
--- 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();