standard compliant errors on EDNS0 about coredns HOT 4 CLOSED

See https://ednscomp.isc.org/compliance/summary.html

from coredns.

First test:

% dig +norec +edns=0 soa miek.nl @linode.atoom.net                            ~
;; ->>HEADER<<- opcode: QUERY; status: NOERROR; id: 59413
;; Flags: qr aa ra; QUERY: 1; ANSWER: 1; AUTHORITY: 0; ADDITIONAL: 0

;; QUESTION SECTION:
;; miek.nl.                 IN  SOA

;; ANSWER SECTION:
miek.nl.                1800    IN  SOA linode.atoom.net. miek.miek.nl. 1460088781 14400 3600 604800 14400

;; Received 82 B
;; Time 2016-04-08 07:40:23 BST
;; From 2a01:7e00::f03c:91ff:feae:e74c@53(UDP) in 9.7 ms

Missing

;; EDNS PSEUDOSECTION:
;; Version: 0; flags: ; UDP size: 4096 B; ext-rcode: Unused

For instance...

Should just put the above page in an edns0_test.go file, load a fake zone. Also take care that that "dropped" zone (i.e. did not enter the middleware) takes care of this. Also check the etcd middleware, prolly need a function in the middleware directory that does most of this, or on state and cache a few bits...

from coredns.

I could add a middleware to add or fixes the EDNS0 in the packet, this would work similar to the rewrite middleware, but is on by default. The only downside is TSIG signed packets - also [IA]XFR... might just go ahead and fix this for the file middleware, see what can be applied to etcd middleware, abstract that and put in the middleware directory.

from coredns.

Fixed in all middleware, respond correctly to EDNS0 options in the middleware.

from coredns.