RFR: 8231260: (dc) DatagramChannel::disconnect changes the port of the local address to 0 (lnx)

[mark sheppard]

OK  Alan, Daniel thanks for the feedback and consideration  … but what you say does lend an argument that
localAddress = null; rather than localAddress = isa;
is a reasonable value in the event of Net.bind throwing a BindException ��

but, as you have said,  that may have other implications

leaving my dead donkey well and truly flogged!!

an influencing (rhetorical) question is
how soon is a port available for re-allocation/re-use after it has been released by the OS on Linux?
with  connected TCP sockets  it would expected to be the TTL setting … not sure about a connected UDP socket!
Would it be instantaneously available after its release by the kernel, or subject to TTL lifetime?

best regards
Mark


________________________________
From: Daniel Fuchs <daniel.fuchs at oracle.com>
Sent: Tuesday 8 October 2019 14:40
To: Alan Bateman <Alan.Bateman at oracle.com>; mark sheppard <macanaoire at hotmail.com>; nio-dev <nio-dev at openjdk.java.net>
Cc: OpenJDK Network Dev list <net-dev at openjdk.java.net>
Subject: Re: RFR: 8231260: (dc) DatagramChannel::disconnect changes the port of the local address to 0 (lnx)

On 08/10/2019 15:29, Alan Bateman wrote:
> On 08/10/2019 15:20, mark sheppard wrote:
>> :
>>
>> Q: is  localAddress.getPort() == 0   indicative that the
>> DatagramChannel is unbound ?
>>
> getLocalAddress() returns a SocketAddress when bound, it returns null
> when not bound. I don't think we should get too hung up on corner case
> that arises when the local port cannot be restored (by re-binding). The
> javadoc sets the expectations that the channel's socket is in an
> undefined state when disconnect fails.

+1 : you would be in uncharted territory and that's exactly why
we want to throw an exception when rebind fails and why we recommend
closing the channel when that happens.

-- daniel

>
> -Alan.

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