It looks like setting and getting the IP_TOS values on the java.net
Sockets is currently broken for some scenarios. It's not possible to set
the value on a ServerSocket via the jdk.net.Sockets.setOption API. See
below for a webrev I'm proposing. It basically makes best efforts to set
the IP_TOS value by mapping it to the IPV6_TCLASS option in an IPV6
enabled environment. NIO follows a similar approach.
Some of the comments in NET_SetSockOpt seem to be legacy and I've
removed the no-op that was in place for IP_TOS. A corner case of setting
of IP_TOS was found on Solaris. It doesn't seem to support setting the
value once the socket is connected. I've handled this via catching of
exception and we should be ok with this since the spec doesn't make any
promises in this area if the socket is connected.
I've been testing various fixes across IPv4/v6 sockets on Solaris, Linux
and macosx. So far, the proposed changes seem to work and wireshark
traces help to confirm that TOS/TCLASS values are being set.
I still need to see if I can improve the getOpt logic for IP_TOS. At the
moment, it can return a cached value which may not represent the true
value in place at kernel socket level. I'll also improve test coverage
in this area.
bug report : https://bugs.openjdk.java.net/browse/JDK-8072384
webrev : http://cr.openjdk.java.net/~coffeys/webrev.8072384.jdk9.v1/webrev/
regards,
Sean.
