From bf6d90600be7eac782e076b7c5f334e83ba9dea0 Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Wed, 30 Mar 2016 16:45:02 +0000
Subject: [PATCH] add closest encloser stuff

---
 middleware/canonical.go         |  7 +++++--
 middleware/file/closest.go      | 16 ++++++++++++++++
 middleware/file/closest_test.go | 34 +++++++++++++++++++++++++++++++++
 middleware/file/dnssec_test.go  |  3 ++-
 middleware/file/lookup.go       |  1 +
 middleware/file/tree/tree.go    | 19 ++++--------------
 6 files changed, 62 insertions(+), 18 deletions(-)
 create mode 100644 middleware/file/closest.go
 create mode 100644 middleware/file/closest_test.go

diff --git a/middleware/canonical.go b/middleware/canonical.go
index 5d51231c2..b8953f655 100644
--- a/middleware/canonical.go
+++ b/middleware/canonical.go
@@ -17,8 +17,11 @@ func Less(a, b string) int {
 	aj := len(a)
 	bj := len(b)
 	for {
-		ai, _ := dns.PrevLabel(a, i)
-		bi, _ := dns.PrevLabel(b, i)
+		ai, oka := dns.PrevLabel(a, i)
+		bi, okb := dns.PrevLabel(b, i)
+		if oka && okb {
+			return 0
+		}
 		// sadly this []byte will allocate...
 		ab := []byte(a[ai:aj])
 		toLowerAndDDD(ab)
diff --git a/middleware/file/closest.go b/middleware/file/closest.go
new file mode 100644
index 000000000..daee27314
--- /dev/null
+++ b/middleware/file/closest.go
@@ -0,0 +1,16 @@
+package file
+
+import "github.com/miekg/dns"
+
+// ClosestEncloser returns the closest encloser for rr.
+func (z *Zone) ClosestEncloser(rr dns.RR) string {
+	elem := z.Tree.Prev(rr)
+	if elem == nil {
+		// SOA?
+		return ""
+	}
+	for _, r := range elem.All() {
+		return r.Header().Name
+	}
+	return ""
+}
diff --git a/middleware/file/closest_test.go b/middleware/file/closest_test.go
new file mode 100644
index 000000000..643e4943f
--- /dev/null
+++ b/middleware/file/closest_test.go
@@ -0,0 +1,34 @@
+package file
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+func TestClosestEncloser(t *testing.T) {
+	z, err := Parse(strings.NewReader(dbMiekNL), testzone, "stdin")
+	if err != nil {
+		t.Fatalf("expect no error when reading zone, got %q", err)
+	}
+
+	tests := []struct {
+		in, out string
+	}{
+		{"miek.nl.", "miek.nl."},
+		{"blaat.miek.nl.", "miek.nl."},
+		{"blaat.blaat.miek.nl.", "miek.nl."},
+		{"blaat.a.miek.nl.", "archive.miek.nl."},
+	}
+
+	mk, _ := dns.TypeToRR[dns.TypeA]
+	rr := mk()
+	for _, tc := range tests {
+		rr.Header().Name = tc.in
+		ce := z.ClosestEncloser(rr)
+		if ce != tc.out {
+			t.Errorf("expected ce to be %s for %s, got %s", tc.out, tc.in, ce)
+		}
+	}
+}
diff --git a/middleware/file/dnssec_test.go b/middleware/file/dnssec_test.go
index 96eff6660..ed8b6a607 100644
--- a/middleware/file/dnssec_test.go
+++ b/middleware/file/dnssec_test.go
@@ -61,9 +61,10 @@ var dnssecTestCases = []coretest.Case{
 		},
 	},
 	{
-		Qname: "b.miek.nl.", Qtype: dns.TypeA, // Do: true, // need sorting first
+		Qname: "b.miek.nl.", Qtype: dns.TypeA, Do: true,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
+			coretest.RRSIG("miek.nl.	1800	IN	RRSIG	SOA 8 2 1800 20160426031301 20160327031301 12051 miek.nl. FIrzy07acBbtyQczy1dc="),
 			coretest.SOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
 		},
 	},
diff --git a/middleware/file/lookup.go b/middleware/file/lookup.go
index 3d3de9679..10f308cf1 100644
--- a/middleware/file/lookup.go
+++ b/middleware/file/lookup.go
@@ -2,6 +2,7 @@ package file
 
 import (
 	"github.com/miekg/coredns/middleware/file/tree"
+
 	"github.com/miekg/dns"
 )
 
diff --git a/middleware/file/tree/tree.go b/middleware/file/tree/tree.go
index 342bcefa8..05dfdfa7d 100644
--- a/middleware/file/tree/tree.go
+++ b/middleware/file/tree/tree.go
@@ -17,8 +17,7 @@ package tree
 // TODO(miek): fix docs
 
 import (
-	"strings"
-
+	"github.com/miekg/coredns/middleware"
 	"github.com/miekg/dns"
 )
 
@@ -112,21 +111,11 @@ func (e *Elem) Delete(rr dns.RR) (empty bool) {
 	return
 }
 
-// TODO(miek): need case ignore compare that is more efficient.
 func Less(a *Elem, rr dns.RR) int {
-	aname := ""
-	for _, ar := range a.m {
-		aname = strings.ToLower(ar[0].Header().Name)
-		break
+	for _, ar := range a.m { // Get first element in a
+		return middleware.Less(ar[0].Header().Name, rr.Header().Name)
 	}
-	rname := strings.ToLower(rr.Header().Name)
-	if aname == rname {
-		return 0
-	}
-	if aname < rname {
-		return -1
-	}
-	return 1
+	return 0
 }
 
 // Assuming the same type and name this will check if the rdata is equal as well.