Proposed changes for Bug 7193520

[Dmitry Samersoff]

John,

linux has both ip_mreq and ip_mreqn structs, but
after better consideration,

I think it's better to *leave this code as is* because
ip_mreq is obsoleted and general direction should be to
use ip_mreqn for all OS that have it but these changes clearly out of
scope of this CR,

-Dmitry

On 2012-09-15 00:06, John Zavgren wrote:
> I agree with all the changes you recommend except the last one... see below.
> ----- Original Message -----
> From: Dmitry.Samersoff at oracle.com
> To: john.zavgren at oracle.com
> Cc: net-dev at openjdk.java.net
> Sent: Friday, September 14, 2012 3:08:57 PM GMT -05:00 US/Canada Eastern
> Subject: Re: Proposed changes for Bug 7193520
> 
> John,
> 
> Changes look good for me.
> Few nits below.
> 
> 
> PlainDatagramSocketImpl.c
> 
> 
> 318  brackets is not necessary anymore
> 
> 1644 whole #ifdef could be removed
>         struct ip_mreqn mreqn;
>      is not necessary anymore,
> 
> 2283 the same
> 
> 2294 #ifdef is not necessary anymore
> ------- This is the original code near line number 2294
> #ifdef __linux__
>                 mname.imr_address.s_addr =
>                     (isOldKernel ? mreqn.imr_address.s_addr : in.s_addr);
> 
> #else
>                 mname.imr_interface.s_addr = in.s_addr;
> #endif
> ---------------
> When Linux is the OS, the structure field name to be set is "imr_address", whereas when other OSes are used, the field name is: imr_interface.
> Am I understanding your suggestion correctly?
> 
> Thanks!
> John
> 
> 
> -Dmitry
> 
> 
> 
> On 2012-09-14 22:22, John Zavgren wrote:
>> Greetings:
>>
>>
>> This bug (7193520) was filed because there are obsolete checks in the openJDK native code that implements datagram sockets, e.g.,
>> src/solaris/native/java/net/PlainDatagramSocketImpl.c
>> and it's Java counterpart:
>> src/share/classes/java/net/AbstractPlainDatagramSocketImpl.java
>>
>> The native code (PlainDatagramSocketImpl.c and "friends") runs real time checks for the Linux kernel version number. If the most significant two fields of the version number is "2.2" on the host platform, then these checks cause the socket to be created, used, and managed differently than if the Linux kernel version were newer. (These behavior changes were necessary because Linux kernel 2.2.X
>> IP networking was was implemented differently and lacked features of the newer kernels.)
>>
>> However, the run time logic isn't actually needed anymore because openJDK doesn't support Linux kernel 2.2.X, and consequently one cannot run openJDK on these older OSes. The run time checks are never used.
>>
>> The proposed changes to the code (http://cr.openjdk.java.net/~chegar/7193520/webrev.00/) eliminate distracting dead wood, and it makes it run (slightly) faster, because the run time checks are eliminated.
>>
>>
>> Thanks!
>> and
>> RSVP
>> John Zavgren
>> john.zavgren at oracle.com
>>
>>
>>
>>
> 
> 


-- 
Dmitry Samersoff
Java Hotspot development team, SPB04
* There will come soft rains ...