X-Recipient: archive-cygwin AT delorie DOT com
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:message-id:date:from:mime-version:to:subject
	:references:in-reply-to:content-type:content-transfer-encoding;
	 q=dns; s=default; b=NdVHFgiup4H/IeVYpfs/HMtTRpT6jS3fTDobBfSluRW
	A7szx6w5P8/ljVcOcgv8x1IUD5nht1aadjHzLGuW8o0Ry1ACOOTUxuhg4SBKQd4f
	r+eP7tkj/Z3uss/dd9T/Gb56Yq+JiNR6iVTAQ1lrI3+k3T5zZAOx/JAST98WkT3g
	=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:message-id:date:from:mime-version:to:subject
	:references:in-reply-to:content-type:content-transfer-encoding;
	 s=default; bh=4l3/dI27tSq69rW9Qa6QpVk9K3M=; b=qj11Q6xR5e6PpRhQj
	48zsTT5efsN2rbCN+QPLZ/My7BlXgI1r1Nfo8vgH6goZUOSmpNXjR57RpN7+xh/q
	JscmHRbp/33C5296U9UWaV5r89aLe4QkWQtnMU1NAlxjL91TRkC0MWQgkvO06CzY
	yiAGrvr9Qp4wPqDy+CDu5GDAsM=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2
X-HELO: na01-bn1-obe.outbound.protection.outlook.com
Message-ID: <54E763CD.9000307@coverity.com>
Date: Fri, 20 Feb 2015 11:41:49 -0500
From: Tom Honermann <thonermann AT coverity DOT com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0
MIME-Version: 1.0
To: <cygwin AT cygwin DOT com>
Subject: Re: [ANNOUNCEMENT] TEST RELEASE: Cygwin 1.7.35-0.3
References: <announce DOT 20150218105937 DOT GA28211 AT calimero DOT vinschen DOT de> <87d255htw7 DOT fsf AT Rainer DOT invalid> <20150220095617 DOT GO26084 AT calimero DOT vinschen DOT de> <54E75BB9 DOT 90807 AT coverity DOT com> <20150220162442 DOT GA26084 AT calimero DOT vinschen DOT de>
In-Reply-To: <20150220162442.GA26084@calimero.vinschen.de>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Transfer-Encoding: 7bit
X-ClientProxiedBy: DM2PR03CA0010.namprd03.prod.outlook.com (10.141.96.20) To BY2PR05MB709.namprd05.prod.outlook.com (10.141.222.142)
Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=thonermann AT coverity DOT com;
X-Microsoft-Antispam: UriScan:;
X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:;SRVR:BY2PR05MB709;
X-Microsoft-Antispam-PRVS:	<BY2PR05MB709F23E561E2BF051EF4424B52A0 AT BY2PR05MB709 DOT namprd05 DOT prod DOT outlook DOT com>
X-Exchange-Antispam-Report-Test: UriScan:;
X-Exchange-Antispam-Report-CFA-Test:	BCL:0;PCL:0;RULEID:(601004)(5005003);SRVR:BY2PR05MB709;
X-Forefront-PRVS: 0493852DA9
X-Forefront-Antispam-Report:	SFV:NSPM;SFS:(10019020)(6049001)(6009001)(3905003)(479174004)(51704005)(5423002)(377454003)(24454002)(199003)(189002)(46102003)(50466002)(93886004)(42186005)(64126003)(36756003)(122386002)(59896002)(23676002)(77096005)(68736005)(105586002)(450100001)(101416001)(106356001)(62966003)(86362001)(2950100001)(19580395003)(87976001)(15975445007)(80316001)(83506001)(65806001)(65956001)(40100003)(117156001)(33656002)(97736003)(66066001)(107886001)(54356999)(110136001)(87266999)(2351001)(77156002)(76176999)(64706001)(65816999)(47776003)(50986999)(92566002);DIR:OUT;SFP:1102;SCL:1;SRVR:BY2PR05MB709;H:[192.168.1.15];FPR:;SPF:None;PTR:InfoNoRecords;A:1;MX:1;LANG:en;
Received-SPF: None (protection.outlook.com: coverity.com does not designate permitted sender hosts)
X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:;SRVR:BY2PR05MB709;
X-OriginatorOrg: coverity.com
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Feb 2015 16:41:54.9419 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY2PR05MB709
X-IsSubscribed: yes

On 02/20/2015 11:24 AM, Corinna Vinschen wrote:
> On Feb 20 11:07, Tom Honermann wrote:
>> On 02/20/2015 04:56 AM, Corinna Vinschen wrote:
>>>> Lastly, running cygserver to cache the LDAP data has another side-effect
>>>> when using VPN.  Since the cygserver is usually started before you've
>>>> dialed into the VPN, your username and some groups will get reported as
>>>> "DOM+User(12345)".  You have to restart cygserver after the VPN is up to
>>>> correct that.
>>>
>>> Yep.  We should contemplate to allow sending a signal to cygserver to
>>> invalidate its cache.
>>
>> Perhaps cygserver could subscribe to network event notifications and
>> automatically invalidate its cache?
>>
>> https://msdn.microsoft.com/en-us/library/windows/desktop/aa366334%28v=vs.85%29.aspx
>
> How do you know if and when an interface change requires a cache
> invalidation?

I doubt there is a perfect algorithm, but perhaps a heuristic would work 
fairly well.  For non-mobile systems, interface changes are presumably 
rather rare and invalidation on the addition of any new interface might 
be acceptable.  For mobile systems migrating between networks, the 
situation is tougher - invalidating the cache when not connected to a 
network from which it can be rebuilt would be frustrating.  An ugly 
solution would be to invalidate depending on whether a (set of) user 
specified address(es) has transitioned from non-reachable to reachable 
(perhaps cache addresses of previously known AD servers?).  A 
not-quite-as-ugly solution might be to invalidate based on specific 
networks (ie, a user specified wifi network name).  None of these sound 
great to me, but perhaps would work well enough in practice.

Tom.

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple