Subject: Re: kern/35196: sockets should die if addresses vanish
To: None <kern-bug-people@netbsd.org, gnats-admin@netbsd.org,>
From: Perry E. Metzger <perry@piermont.com>
List: netbsd-bugs
Date: 12/07/2006 14:25:04
The following reply was made to PR kern/35196; it has been noted by GNATS.

From: "Perry E. Metzger" <perry@piermont.com>
To: SODA Noriyuki <soda@sra.co.jp>
Cc: gnats-bugs@NetBSD.org, kern-bug-people@NetBSD.org,
	gnats-admin@NetBSD.org, netbsd-bugs@NetBSD.org
Subject: Re: kern/35196: sockets should die if addresses vanish
Date: Thu, 07 Dec 2006 09:22:54 -0500

 SODA Noriyuki <soda@sra.co.jp> writes:
 >>>>>> On Thu,  7 Dec 2006 02:25:01 +0000 (UTC), perry@piermont.com said:
 >> The addresses bound to said interface will often go away, to be
 >> replaced by new ones (or none at all). However, even after they go
 >> away, TCP connections will continue to live for quite some time,
 >> eventually timing out, going into time wait, etc.
 >
 >> This is quite clearly silly.
 >
 > It is not so silly, acutally.
 > Think about unstable PPP link which nearly always assigns same IP
 > address for each host.
 > With current behavior, we can still use same TCP connect, after the
 > links goes down and then the link is reconnected.
 
 My problem is when the address does *not* return, which also happens
 in a lot of cases. Perhaps we could have a sysctl to control my
 proposed behavior (or to add a switch+timeout for it) so that users
 can pick their preferred behavior based on their usage pattern.
 
 Another alternative would be to tear down the connections when the
 same interface comes up again but with a different IP address.
 
 Perry