PowerDNS Forward-Notify Patch #1701

DrRemorse · 2014-09-04T21:46:38Z

This patch will allow you to redirect PowerDNS notifications to a "passthru" server. It is intended to fix notify/axfr behavior in anycast clusters of PowerDNS auth servers however it may be useful for other situations.

The configuration option "passthru-notify" has been added to the pdns.conf parser. The option accepts multiple IPv4 and IPv6 address values.

This patch obsoletes issue #655.

Ralph Covelli
Hurricane Electric / AS6939
rcovelli@he.net

klaus3000 · 2014-09-05T11:59:14Z

IMO the feature name is confusing. I would call it "notify-override" (NOTIFY this targets instead of the zones NS set).

cmouse · 2014-09-06T08:24:24Z

@DrRemorse Your build failed because pdns.conf-dist differs from output of pdns --config. (Asked in IRC).

Habbie · 2015-05-06T13:05:04Z

Thank you for this patch!

I'm happy to merge this with some changes:

a rebase (we changed a lot of code on our end, sorry about that)
making sure Travis passes
a rename to forward-notify or something similar
the testIPv6addr function (and the v4 equivalent) almost certainly duplicate code we already have, can you look into cleaning that up? I presume ComboAddress can already do the checking.
clear documentation; right now this feature both forwards incoming NOTIFYs and overrides the target of locally initiated NOTIFYs. Given the override can also be done with a combination of also-notify and only-notify I am somewhat tempted to remove the override feature in full.

Then, we need a review to make sure the static Resolver passthruResolver really is safe, I'm happy to do that.

We're happy to help with any of the above steps if you have trouble with them or can't find the time. Do let us know!

This reverts commit e4f5f30.

This reverts commit ba2fa53.

klaus3000 · 2016-12-27T21:20:18Z

Which problem are you actually trying to solve? There are plenty of notification options already in PDNS.

klaus3000 · 2017-01-06T08:47:35Z

Hi DrRemorse! I still do not understand your problem. We also use PDNS in Anycast Clusters but do not have problems. There are plenty of options like notify-only, slave-renotify, ALSO-NOTIFY and what we do, we changed some default SQL queries to a SQL function which has some additional notify logic, so we do lots of notify tricks without any code changes.

removed forward-notify from mastercommunicator.cc must startup communicator if forward-notify is specified

DrRemorse · 2017-01-09T03:36:14Z

Hi,

We operate a large anycast cluster of PowerDNS servers as well. Our servers are not configured as masters or slaves. Internally the backend handles synchronization however we can also be configured to slave zones off other user's servers. In this case when the user's server sends us a notification we use this feature to relay that notification to an AXFR controller which then in turn pulls the zone from the user's server. There may be other methods of accomplishing this however we found this way efficient and scalable. We are offering this to the community in the hopes that someone will find it as useful as we did.

Thanks!

klaus3000 · 2017-01-09T07:58:42Z

Basically our setup may be similar: 1 "control server" PDNS fetching the zone from the customers and receiving NOTIFYs from the customers. Zone are configured with type=SLAVE. The backend is replicated to the anycast nodes (Postgresql+Slony) and the anycast nodes operate with type=NATIVE. To prevent the "control server" to send automatic NOTIFYs to the NS hostnames we use "only-notify=". Customers can also fetch their zones from our control server. Therefore we have slave-renotify=yes and set ALSO-NOTIFY for these customer's zones. So, no code big changes are needed (only one optimizations: #4861)

pieterlexis · 2017-01-25T16:36:14Z

pdns/communicator.cc

+    }
+    catch(PDNSException &e) {
+      L<<Logger::Error<<"Unparseable IP in forward-notify. Error: "<<e.reason<<endl;
+      exit(1);


please don't kill the daemon on error

Hi,

It was written like this to be consistent with the behavior of also-notify, only-notify and friends which directly precede this chunk of code. This code is only run once at pdns startup.

Thanks!

Habbie · 2017-01-30T19:42:00Z

After IRC discussion: needs some squashing, but given the small size of the total change, please feel free to squash it all into one commit.

Habbie

Looks to be in good shape. One nit, one question.

Habbie · 2017-01-31T14:24:57Z

pdns/packethandler.cc

@@ -886,7 +888,17 @@ int PacketHandler::processNotify(DNSPacket *p)

  // ok, we've done our checks
  di.backend = 0;
-  Communicator.addSlaveCheckRequest(di, p->d_remote);
+
+  if(!::arg()["forward-notify"].empty()) {


It's cheaper to check if PacketHandler::s_forwardNotify is empty.

Good call. Ill make the change and squash tonight.

Habbie · 2017-01-31T14:38:08Z

pdns/packethandler.cc

+    }
+  }
+
+  if(::arg().mustDo("slave"))


Is this intentional? What is the behaviour change here?

This is intentional to preserve the original pdns behavior due to my conditional change at the top of the function: if(!::arg().mustDo("slave") && ::arg()["forward-notify"].empty()) ...

…ify.empty() checks

This patch will allow you to redirect inbound notifications to a proxy server. It's intended use is in anycast environments where it might be nessessary for a proxy server to preform the AXFR. The configuration option "forward-notify" has been added to the pdns.conf parser. The option accepts multiple IPv4 and IPv6 address values.

Habbie added auth enhancement labels Sep 15, 2014

Habbie mentioned this pull request Sep 30, 2014

Add nproxy support into pdns. #539

Closed

Ralph Covelli added 2 commits November 4, 2014 16:22

PowerDNS Passthru Notify Patch #7

ba2fa53

forgot to add default example values for pdns_server --config

e4f5f30

Habbie mentioned this pull request Jan 26, 2015

No manpage or docs for nproxy #2099

Closed

pieterlexis added this to the auth-4.0.0 milestone Jun 9, 2015

Habbie modified the milestones: auth-4.1.0, auth-4.0.0 Dec 15, 2015

Ralph Covelli added 7 commits December 23, 2016 02:12

Revert "forgot to add default example values for pdns_server --config"

e3bff36

This reverts commit e4f5f30.

Revert "PowerDNS Passthru Notify Patch #7"

62e38ee

This reverts commit ba2fa53.

Merge branch 'master' of http://github.com/PowerDNS/pdns

5c193b6

rebase

34e9d08

changed name from passthru-notify to forward-notify

2d1956e

removed testIPv4addr() and testIPv6addr()

0d7f861

slightly better documentation

481c475

DrRemorse changed the title ~~PowerDNS Passthru Notify Patch~~ PowerDNS Forward-Notify Patch Dec 27, 2016

DrRemorse and others added 2 commits December 26, 2016 22:54

Update misc.cc

08dac86

removed unused ComboAddress local in relayNotification()

6a21309

Ralph Covelli and others added 4 commits January 1, 2017 03:50

removed relayNotification()

1c99143

Update resolver.hh

0188de2

switched Warning back to Error... oops

ddc5e42

replaced ResolverException with PDNSException

ae2371d

Ralph Covelli added 2 commits January 9, 2017 02:33

load forward-notify list on startup

a3201e8

removed forward-notify from mastercommunicator.cc must startup communicator if forward-notify is specified

fixed docs

7be40d8

Merge remote-tracking branch 'upstream/master'

6f7a384

Ralph Covelli added 2 commits January 17, 2017 04:21

changed useless nested if to && ...oops

97f7698

small formatting fix oops

da484dd

pieterlexis reviewed Jan 25, 2017

View reviewed changes

Habbie self-assigned this Jan 30, 2017

Habbie reviewed Jan 31, 2017

View reviewed changes

Ralph Covelli added 3 commits February 1, 2017 01:32

changed some ::arg()["forward-notify"].empty() checks to s_forwardNot…

8726f45

…ify.empty() checks

Merge branch 'master' of http://github.com/DrRemorse/pdns

234d766

DrRemorse closed this Feb 1, 2017

DrRemorse mentioned this pull request Feb 1, 2017

PowerDNS Forward-Notify Patch #4964

Closed

ahupowerdns modified the milestone: auth-4.1.0 Feb 23, 2017

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PowerDNS Forward-Notify Patch #1701

PowerDNS Forward-Notify Patch #1701

DrRemorse commented Sep 4, 2014

klaus3000 commented Sep 5, 2014

cmouse commented Sep 6, 2014

Habbie commented May 6, 2015

klaus3000 commented Dec 27, 2016

klaus3000 commented Jan 6, 2017

DrRemorse commented Jan 9, 2017

klaus3000 commented Jan 9, 2017

pieterlexis Jan 25, 2017

DrRemorse Jan 30, 2017

Habbie commented Jan 30, 2017

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Habbie Jan 31, 2017

DrRemorse Jan 31, 2017

Habbie Jan 31, 2017

DrRemorse Jan 31, 2017

PowerDNS Forward-Notify Patch #1701

PowerDNS Forward-Notify Patch #1701

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DrRemorse commented Sep 4, 2014

klaus3000 commented Sep 5, 2014

cmouse commented Sep 6, 2014

Habbie commented May 6, 2015

klaus3000 commented Dec 27, 2016

klaus3000 commented Jan 6, 2017

DrRemorse commented Jan 9, 2017

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