Arthur,
> On 16 May 2019, at 00:24, Arthur Eubanks <[email protected]> wrote:
>
> webrev: http://cr.openjdk.java.net/~aeubanks/8224014/webrev.00/
> <http://cr.openjdk.java.net/~aeubanks/8224014/webrev.00/>
> bug: https://bugs.openjdk.java.net/browse/JDK-8224014
> <https://bugs.openjdk.java.net/browse/JDK-8224014>
>
> In https://bugs.openjdk.java.net/browse/JDK-8220673
> <https://bugs.openjdk.java.net/browse/JDK-8220673>, I missed
> skipping test/jdk/java/net/NetworkInterface/IPv4Only.java when running in an
> IPv6 only environment. It should have a call to
> IPSupport.throwSkippedExceptionIfNonOperational().
After the change for 8223532 in NetworkInterface.c, it is no longer
required that AF_INET sockets be able to be created, coupled with
-Djava.net.preferIPv4Stack=true, enumInterfaces may return NULL, which
in turn bubbles up to the Java layer, in this case getNetworkInterfaces,
as null ( rather than a collection containing the interfaces ).
The specification for NetworkInterface::getNetworkInterfaces guarantees
that there be at least one element in the returned collection, but there
cannot be since the system is mis-configured ( the underlying platform
is IPv6-only coupled with -Djava.net.preferIPv4Stack=true ). The only
sensible thing for the NetworkInterface implementation to do is to throw
an exception ( which is perfectly fine as per its specification,
"java.net.SocketException: No network interfaces configured" ).
Rather than skipping the test, which will clearly work, an alternative
is to ensure that an exception is thrown for this case, e.g.
if (IPSupport.hasIPv4()) {
out.println("Testing IPv4");
Enumeration<NetworkInterface> nifs =
NetworkInterface.getNetworkInterfaces();
while (nifs.hasMoreElements()) {
NetworkInterface nif = nifs.nextElement();
Enumeration<InetAddress> addrs = nif.getInetAddresses();
while (addrs.hasMoreElements()) {
InetAddress hostAddr = addrs.nextElement();
if ( hostAddr instanceof Inet6Address ){
throw new RuntimeException( "NetworkInterfaceV6List failed
- found v6 address " + hostAddr.getHostAddress() );
}
}
}
} else {
// No platform IPv4 support & -Djava.net.preferIPv4Stack=true
out.println("Testing without IPv4 support");
try {
NetworkInterface.getNetworkInterfaces();
} catch (SocketException expected) {
out.println("caught expected exception: " + expected);
}
try {
NetworkInterface.networkInterfaces();
} catch (SocketException expected) {
out.println("caught expected exception: " + expected);
}
}
-Chris.
