RFR:8194298 Add support for per Socket configuration of TCP keepalive

[vyom tewari]

Hi,

Please find the latest 
webrev(http://cr.openjdk.java.net/~vtewari/8194298/webrev0.2/index.html). 
I incorporated most of the review comments. Chris as you suggested in 
below mail i did not added the note for upper-bound because values are 
also OS specific.

Thanks,

Vyom


On Monday 23 April 2018 07:26 PM, Chris Hegarty wrote:
>
> On 23/04/18 13:34, Alan Bateman wrote:
>> On 23/04/2018 13:05, vyom tewari wrote:
>>> Hi,
>>>
>>> Please find the latest 
>>> webrev(http://cr.openjdk.java.net/~vtewari/8194298/webrev0.1/index.html). 
>>> I incorporated  most of the review comments.
>> This looks much better but I think the second paragraph of the spec 
>> of each option needs to be inverted so that it states clearly what 
>> the options does before it gets into the background of SO_KEEPALIVE. 
>> For example, TCP_KEEPALIVE should say that it sets the idle period 
>> for keep alive before it explains SO_KEEPALIVE. 
>
> Mea culpa, I ordered the paragraphs as they are to be consistent
> with TCP_QUICKACK. I don't have any objection if they are reversed.
>
>> The currently wording also begs questions as to whether the socket 
>> option means anything when SO_KEEPALIVE is not enabled.
>
> It's implicit. The option can still be set and its value retrieved.
>
>
>> Also it probably should say something about whether it can be changed 
>> at any time or not.
>
> You can set it any time. Of course, it may not be effective
> immediately, depending on the exact state of the socket.
>
> We may also want to add a note that the accepted values may
> have an upper-bound. For example, the following is the largest
> set of values that I can set on my Ubuntu Linux, without an
> exception being thrown [*].
>
>  TCP_KEEPIDLE = 32767
>  TCP_KEEPINTERVAL = 32767
>  TCP_KEEPCOUNT = 127
>
> -Chris.
>
> [*] "java.net.SocketException: Invalid argument" when a given
> value is "too" large.