path: root/src
diff options
authorRobin Burchell <>2012-03-30 16:23:24 +0200
committerQt by Nokia <>2012-04-02 12:49:38 +0200
commitc82d40749dc1ce816333e84d7f3232e59fbe2058 (patch)
tree340231cf80134be4ac7b3b82cbd522ec320a3e5d /src
parentc7f8f459bd9bb388aa06d2fb4564012d3eec3906 (diff)
Fix multicast join/leave when binding to QHostAddress::Any.
On OS X and Windows, this was not working, because the socket was being bound in v6 mode (due to ::Any being for dual mode), but the address passed was a v4 address, meaning it took the wrong codepath. Linux, strangely, apparently works anyway. This is fixable in OS X (by using the v6 join path when bound in v6/dual mode), but the same fix doesn't work on Windows, failing with WSAEADDRNOTAVAIL. Don't allow this behaviour, and provide a sane error message telling the user what to do instead. Done-with: Shane Kearns Task-number: QTBUG-25047 Change-Id: Iaf5bbee82e13ac92e11b60c558f5af9ce26f474b Reviewed-by: Shane Kearns <>
Diffstat (limited to 'src')
2 files changed, 17 insertions, 0 deletions
diff --git a/src/network/socket/qnativesocketengine.cpp b/src/network/socket/qnativesocketengine.cpp
index a34b19f7ef..8fac3613c0 100644
--- a/src/network/socket/qnativesocketengine.cpp
+++ b/src/network/socket/qnativesocketengine.cpp
@@ -637,6 +637,19 @@ bool QNativeSocketEngine::joinMulticastGroup(const QHostAddress &groupAddress,
Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::joinMulticastGroup(), false);
Q_CHECK_STATE(QNativeSocketEngine::joinMulticastGroup(), QAbstractSocket::BoundState, false);
Q_CHECK_TYPE(QNativeSocketEngine::joinMulticastGroup(), QAbstractSocket::UdpSocket, false);
+ // if the user binds a socket to an IPv6 address (or QHostAddress::Any) and
+ // then attempts to join an IPv4 multicast group, this won't work on
+ // Windows. In order to make this cross-platform, we warn & fail on all
+ // platforms.
+ if (groupAddress.protocol() == QAbstractSocket::IPv4Protocol &&
+ (d->socketProtocol == QAbstractSocket::IPv6Protocol ||
+ d->socketProtocol == QAbstractSocket::AnyIPProtocol)) {
+ qWarning("QAbstractSocket: cannot bind to QHostAddress::Any (or an IPv6 address) and join an IPv4 multicast group");
+ qWarning("QAbstractSocket: bind to QHostAddress::AnyIPv4 instead if you want to do this");
+ return false;
+ }
return d->nativeJoinMulticastGroup(groupAddress, iface);
diff --git a/src/network/socket/qudpsocket.cpp b/src/network/socket/qudpsocket.cpp
index ec751c289e..23c1956ec5 100644
--- a/src/network/socket/qudpsocket.cpp
+++ b/src/network/socket/qudpsocket.cpp
@@ -178,6 +178,10 @@ QUdpSocket::~QUdpSocket()
interface chosen by the operating system. The socket must be in BoundState,
otherwise an error occurs.
+ Note that if you are attempting to join an IPv4 group, your socket must not
+ be bound using IPv6 (or in dual mode, using QHostAddress::Any). You must use
+ QHostAddress::AnyIPv4 instead.
This function returns true if successful; otherwise it returns false
and sets the socket error accordingly.