On 08/05/2020 14:43, Patrick Concannon wrote:
Hi,
Could someone please review my fix for JDK-8242885
'PlainDatagramSocketImpl doesn’t allow for the sending of IPv6
datagrams on macOS with sizes between 65508-65527 bytes'?
This fix changes the current max size for IPv6 datagrams on macOS from
it's current size of 65507, which is the IPv4 limit, to65527, the
actual limit for IPv6 on macOS. This will get around the issue of not
being able to send datagrams with sizes between65508-65527 bytes.
bug: https://bugs.openjdk.java.net/browse/JDK-8242885
webrev: http://cr.openjdk.java.net/~pconcannon/8242885/webrevs/webrev.00/
Given that PDSI will not be used by default then I think this minimal
fix is okay. If PDSI were to remain the default then the right thing
would be to check the initial value of SO_SNDBUF first so that this code
doesn't reduce the size when it has been configured to a larger value
(with sysctl). The code to change SO_RCVBUF would also be removed.
You added SetGetSendBufferSize.java recently to test the
set/getSendBufferSize methods. The test in this webrev overlaps a bit.
Does testInitialSendBufferSize go away or change to test the limit when
the socket is IPv6?
In the new test, sendLargeDatagram sends large datagrams through the
loopback but it doesn't check that they can be received. I think an
end-to-end test would be more useful. I don't know if there is any
equivalent of fragmentation when sending large datagrams through the
loopback interface on macOS. I think we will only have confidence with
an end-to-end test if it sends it on the network (not the loopback).
-Alan
