From 075098e0db8f8a8bf1dac3d591b6bd533db2bc70 Mon Sep 17 00:00:00 2001
From: Thorvald Natvig <slicer@users.sourceforge.net>
Date: Sun, 27 Dec 2009 00:51:40 +0100
Subject: [PATCH] Listen to IPv4 explicitly if IPV6_V6ONLY is 1

---
 src/murmur/Meta.cpp | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/murmur/Meta.cpp b/src/murmur/Meta.cpp
index 26e687fbf..9387bb73d 100644
--- a/src/murmur/Meta.cpp
+++ b/src/murmur/Meta.cpp
@@ -189,13 +189,25 @@ void MetaParams::read(QString fname) {
 			}
 		}
 
-		if (hasipv6)
+		if (hasipv6) {
 			qlBind << QHostAddress(QHostAddress::AnyIPv6);
 #ifdef Q_OS_UNIX
-		else
+			if (hasipv4) {
+				int s = ::socket(AF_INET6, SOCK_STREAM, 0);
+				if (s != -1) {
+					int ipv6only = 0;
+					socklen_t optlen = sizeof(ipv6only);
+					if (getsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &ipv6only, &optlen) == 0) {
+						if (ipv6only == 0)
+							hasipv4 = false;
+					}
+					close(s);
+				}
+			}
 #endif
-			if (hasipv4)
-				qlBind << QHostAddress(QHostAddress::Any);
+		}
+		if (hasipv4)
+			qlBind << QHostAddress(QHostAddress::Any);
 	}
 
 	qsPassword = qsSettings->value("serverpassword", qsPassword).toString();