On 20/12/2019 17:53, Chris Hegarty wrote:
The MulticastSocket implementation on Windows uses the two stacks
implementation. The two stacks implementation creates a socket on the
IPv4 stack and another on the IPv6 stack. Operations are then performed
on both sockets as appropriate. If the socket is bound to a specific
address, then the IP version of the socket that matches that address is
retained, and the other closed.
This is a complicated implementation, which will hopefully be replaced
soon, but in the meantime there is a serious bug with handling the
IP_MULTICAST_IF[2] socket option. The code does not correctly cater for
the fact that one of the file descriptors may be closed, leading to
SocketExceptions with a message of: "An operation was attempted on
something that is not a socket (Error setting socket option)"
Webrev:
https://cr.openjdk.java.net/~chegar/8236441/webrev.00/
JIRA:
https://bugs.openjdk.java.net/browse/JDK-8236441
This looks okay to me. There are a few inconsistencies in this code in
that some places it checks if fd1 >= 0, others != -1 but I don't think
there are correctness issues. You probably don't need to check
ipv6_supported as fd1 can't be valid if IPv6 is disabled but won't
change the branches that are executed.
In passing, the pre-existing comment at L1881 in this patch doesn't look
right. The index will be 0 when an outgoing interface is not set.
-Alan.
