Default to scrubbing replies in the server (#2012)

Every plugin needs to deal with EDNS0 and should call Scrub to make a
message fit the client's buffer. Move this functionality into the server
and wrapping the ResponseWriter into a ScrubWriter that handles these
bits for us. Result:

Less code and faster, because multiple chained plugins could all be
calling scrub and SizeAndDo - now there is just one place.

Most tests in file/* and dnssec/* needed adjusting because in those unit
tests you don't see OPT RRs anymore. The DNSSEC signer was also looking
at the returned OPT RR to see if it needed to sign - as those are now
added by the server (and thus later), this needed to change slightly.

Scrub itself still exist (for backward compat reasons), but has been
made a noop. Scrub has been renamed to scrub as it should not be used by
external plugins.

Fixes: #2010

Signed-off-by: Miek Gieben <miek@miek.nl>

1 files changed, 4 insertions, 14 deletions

diff --git a/plugin/file/dnssec_test.go b/plugin/file/dnssec_test.go
index 29cd9a61e..fee39a37a 100644
--- a/plugin/file/dnssec_test.go
+++ b/plugin/file/dnssec_test.go
@@ -11,6 +11,7 @@ import (
 	"github.com/miekg/dns"
 )
 
+// All OPT RR are added in server.go, so we don't specify them in the unit tests.
 var dnssecTestCases = []test.Case{
 	{
 		Qname: "miek.nl.", Qtype: dns.TypeSOA, Do: true,
@@ -18,8 +19,7 @@ var dnssecTestCases = []test.Case{
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	SOA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. FIrzy07acBbtyQczy1dc="),
 			test.SOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
 		},
-		Ns:    auth,
-		Extra: []dns.RR{test.OPT(4096, true)},
+		Ns: auth,
 	},
 	{
 		Qname: "miek.nl.", Qtype: dns.TypeAAAA, Do: true,
@@ -27,8 +27,7 @@ var dnssecTestCases = []test.Case{
 			test.AAAA("miek.nl.	1800	IN	AAAA	2a01:7e00::f03c:91ff:fef1:6735"),
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	AAAA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. SsRT="),
 		},
-		Ns:    auth,
-		Extra: []dns.RR{test.OPT(4096, true)},
+		Ns: auth,
 	},
 	{
 		Qname: "miek.nl.", Qtype: dns.TypeNS, Do: true,
@@ -39,7 +38,6 @@ var dnssecTestCases = []test.Case{
 			test.NS("miek.nl.	1800	IN	NS	omval.tednet.nl."),
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	NS 8 2 1800 20160426031301 20160327031301 12051 miek.nl. ZLtsQhwaz+lHfNpztFoR1Vxs="),
 		},
-		Extra: []dns.RR{test.OPT(4096, true)},
 	},
 	{
 		Qname: "miek.nl.", Qtype: dns.TypeMX, Do: true,
@@ -51,8 +49,7 @@ var dnssecTestCases = []test.Case{
 			test.MX("miek.nl.	1800	IN	MX	5 alt2.aspmx.l.google.com."),
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	MX 8 2 1800 20160426031301 20160327031301 12051 miek.nl. kLqG+iOr="),
 		},
-		Ns:    auth,
-		Extra: []dns.RR{test.OPT(4096, true)},
+		Ns: auth,
 	},
 	{
 		Qname: "www.miek.nl.", Qtype: dns.TypeA, Do: true,
@@ -63,9 +60,6 @@ var dnssecTestCases = []test.Case{
 			test.RRSIG("www.miek.nl. 1800	RRSIG	CNAME 8 3 1800 20160426031301 20160327031301 12051 miek.nl.  NVZmMJaypS+wDL2Lar4Zw1zF"),
 		},
 		Ns: auth,
-		Extra: []dns.RR{
-			test.OPT(4096, true),
-		},
 	},
 	{
 		// NoData
@@ -76,7 +70,6 @@ var dnssecTestCases = []test.Case{
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	SOA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. FIrzy07acBbtyQczy1dc="),
 			test.SOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
 		},
-		Extra: []dns.RR{test.OPT(4096, true)},
 	},
 	{
 		Qname: "b.miek.nl.", Qtype: dns.TypeA, Do: true,
@@ -89,7 +82,6 @@ var dnssecTestCases = []test.Case{
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	SOA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. FIrzy07acBbtyQczy1dc="),
 			test.SOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
 		},
-		Extra: []dns.RR{test.OPT(4096, true)},
 	},
 	{
 		Qname: "b.blaat.miek.nl.", Qtype: dns.TypeA, Do: true,
@@ -102,7 +94,6 @@ var dnssecTestCases = []test.Case{
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	SOA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. FIrzy07acBbtyQczy1dc="),
 			test.SOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
 		},
-		Extra: []dns.RR{test.OPT(4096, true)},
 	},
 	{
 		Qname: "b.a.miek.nl.", Qtype: dns.TypeA, Do: true,
@@ -114,7 +105,6 @@ var dnssecTestCases = []test.Case{
 			test.RRSIG("miek.nl.	1800	IN	RRSIG	SOA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. FIrzy07acBbtyQczy1dc="),
 			test.SOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
 		},
-		Extra: []dns.RR{test.OPT(4096, true)},
 	},
 }