Implement a DNS zone

Full implementation, DNS (and in the future DNSSEC). Returns answer in a
hopefully standards compliant way.
Testing with my miek.nl zone are included as well.
This should correctly handle nodata, nxdomain and cnames.

core/setup/file.go

 package setup
 
 import (
-	"log"
 	"os"
 
 	"github.com/miekg/coredns/middleware"
 	"github.com/miekg/coredns/middleware/file"
-
-	"github.com/miekg/dns"
 )
 
 // File sets up the file middleware.
@@ -23,8 +20,7 @@ func File(c *Controller) (middleware.Middleware, error) {
 }
 
 func fileParse(c *Controller) (file.Zones, error) {
-	// Maybe multiple, each for each zone.
-	z := make(map[string]file.Zone)
+	z := make(map[string]*file.Zone)
 	names := []string{}
 	for c.Next() {
 		if c.Val() == "file" {
@@ -42,7 +38,12 @@ func fileParse(c *Controller) (file.Zones, error) {
 			// normalize this origin
 			origin = middleware.Host(origin).StandardHost()
 
-			zone, err := parseZone(origin, fileName)
+			reader, err := os.Open(fileName)
+			if err != nil {
+				return file.Zones{}, err
+			}
+
+			zone, err := file.Parse(reader, origin, fileName)
 			if err == nil {
 				z[origin] = zone
 			}
@@ -51,24 +52,3 @@ func fileParse(c *Controller) (file.Zones, error) {
 	}
 	return file.Zones{Z: z, Names: names}, nil
 }
-
-//
-// parsrZone parses the zone in filename and returns a []RR or an error.
-func parseZone(origin, fileName string) (file.Zone, error) {
-	f, err := os.Open(fileName)
-	if err != nil {
-		return nil, err
-	}
-	tokens := dns.ParseZone(f, origin, fileName)
-	zone := make([]dns.RR, 0, defaultZoneSize)
-	for x := range tokens {
-		if x.Error != nil {
-			log.Printf("[ERROR] failed to parse %s: %v", origin, x.Error)
-			return nil, x.Error
-		}
-		zone = append(zone, x.RR)
-	}
-	return file.Zone(zone), nil
-}
-
-const defaultZoneSize = 20 // A made up number.

middleware/etcd/handler.go

@@ -14,7 +14,8 @@ func (e Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 		return e.Next.ServeDNS(ctx, w, r)
 	}
 
-	m := state.AnswerMessage()
+	m := new(dns.Msg)
+	m.SetReply(r)
 	m.Authoritative, m.RecursionAvailable, m.Compress = true, true, true
 
 	var (

middleware/file/file.go

@@ -6,12 +6,13 @@ package file
 // have some fluff for DNSSEC (and be memory efficient).
 
 import (
-	"strings"
-
-	"golang.org/x/net/context"
+	"io"
+	"log"
 
 	"github.com/miekg/coredns/middleware"
+
 	"github.com/miekg/dns"
+	"golang.org/x/net/context"
 )
 
 type (
@@ -21,9 +22,8 @@ type (
 		// Maybe a list of all zones as well, as a []string?
 	}
 
-	Zone  []dns.RR
 	Zones struct {
-		Z     map[string]Zone // utterly braindead impl. TODO(miek): fix
+		Z     map[string]*Zone
 		Names []string
 	}
 )
@@ -35,57 +35,51 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 	if zone == "" {
 		return f.Next.ServeDNS(ctx, w, r)
 	}
+	z, ok := f.Zones.Z[zone]
+	if !ok {
+		return f.Next.ServeDNS(ctx, w, r)
+	}
 
-	names, nodata := f.Zones.Z[zone].lookup(qname, state.QType())
-	var answer *dns.Msg
-	switch {
-	case nodata:
-		answer = state.AnswerMessage()
-		answer.Ns = names
-	case len(names) == 0:
-		answer = state.AnswerMessage()
-		answer.Ns = names
-		answer.Rcode = dns.RcodeNameError
-	case len(names) > 0:
-		answer = state.AnswerMessage()
-		answer.Answer = names
+	rrs, extra, result := z.Lookup(qname, state.QType(), state.Do())
+
+	m := new(dns.Msg)
+	m.SetReply(r)
+	m.Authoritative, m.RecursionAvailable, m.Compress = true, true, true
+
+	switch result {
+	case Success:
+		// case?
+		m.Answer = rrs
+		m.Extra = extra
+		// Ns section
+	case NameError:
+		m.Rcode = dns.RcodeNameError
+		fallthrough
+	case NoData:
+		// case?
+		m.Ns = rrs
 	default:
-		answer = state.ErrorMessage(dns.RcodeServerFailure)
+		// TODO
 	}
-	// Check return size, etc. TODO(miek)
-	w.WriteMsg(answer)
-	return 0, nil
+	// sizing and Do bit RRSIG
+	w.WriteMsg(m)
+	return dns.RcodeSuccess, nil
 }
 
-// Lookup will try to find qname and qtype in z. It returns the
-// records found *or* a boolean saying NODATA. If the answer
-// is NODATA then the RR returned is the SOA record.
-//
-// TODO(miek): EXTREMELY STUPID IMPLEMENTATION.
-// Doesn't do much, no delegation, no cname, nothing really, etc.
-// TODO(miek): even NODATA looks broken
-func (z Zone) lookup(qname string, qtype uint16) ([]dns.RR, bool) {
-	var (
-		nodata bool
-		rep    []dns.RR
-		soa    dns.RR
-	)
-
-	for _, rr := range z {
-		if rr.Header().Rrtype == dns.TypeSOA {
-			soa = rr
+// Parse parses the zone in filename and returns a new Zone or an error.
+func Parse(f io.Reader, origin, fileName string) (*Zone, error) {
+	tokens := dns.ParseZone(f, dns.Fqdn(origin), fileName)
+	z := NewZone(origin)
+	for x := range tokens {
+		if x.Error != nil {
+			log.Printf("[ERROR] failed to parse %s: %v", origin, x.Error)
+			return nil, x.Error
 		}
-		// Match function in Go DNS?
-		if strings.ToLower(rr.Header().Name) == qname {
-			if rr.Header().Rrtype == qtype {
-				rep = append(rep, rr)
-				nodata = false
-			}
-
+		if x.RR.Header().Rrtype == dns.TypeSOA {
+			z.SOA = x.RR.(*dns.SOA)
+			continue
 		}
+		z.Insert(x.RR)
 	}
-	if nodata {
-		return []dns.RR{soa}, true
-	}
-	return rep, false
+	return z, nil
 }

middleware/file/file.md

+# file
+
+`file` enabled reading zone data from a RFC-1035 styled file.
+
+The etcd middleware makes extensive use of the proxy middleware to forward and query
+other servers in the network.
+
+## Syntax
+
+~~~
+file dbfile [zones...]
+~~~
+
+* `dbfile` the database file to read and parse.
+* `zones` zones it should be authoritative for. If empty the zones from the configuration block
+    are used.
+
+If you want to `round robin` A and AAAA responses look at the `loadbalance` middleware.
+
+~~~
+file {
+    db <dsds>
+    masters [...masters...]
+}
+~~~
+
+
+
+
+
+* `path` /skydns
+* `endpoint` endpoints...
+* `stubzones`
+
+## Examples
+
+dnssec {
+    file blaat, transparant allow already signed responses
+    ksk bliep.dsdsk
+}

middleware/file/lookup.go

+package file
+
+import "github.com/miekg/dns"
+
+// Result is the result of a Lookup
+type Result int
+
+const (
+	Success Result = iota
+	NameError
+	NoData // aint no offical NoData return code.
+)
+
+// Lookup looks up qname and qtype in the zone, when do is true DNSSEC are included as well.
+// Two sets of records are returned, one for the answer and one for the additional section.
+func (z *Zone) Lookup(qname string, qtype uint16, do bool) ([]dns.RR, []dns.RR, Result) {
+	// TODO(miek): implement DNSSEC
+	var rr dns.RR
+	mk, known := dns.TypeToRR[qtype]
+	if !known {
+		return nil, nil, NameError
+		// Uhm...?
+		// rr = new(RFC3597)
+	} else {
+		rr = mk()
+	}
+	if qtype == dns.TypeSOA {
+		return z.lookupSOA(do)
+	}
+
+	rr.Header().Name = qname
+	elem := z.Tree.Get(rr)
+	if elem == nil {
+		return []dns.RR{z.SOA}, nil, NameError
+	}
+	rrs := elem.Types(dns.TypeCNAME)
+	if len(rrs) > 0 { // should only ever be 1 actually; TODO(miek) check for this?
+		// lookup target from the cname
+		rr.Header().Name = rrs[0].(*dns.CNAME).Target
+		elem := z.Tree.Get(rr)
+		if elem == nil {
+			return rrs, nil, Success
+		}
+		return rrs, elem.All(), Success
+	}
+
+	rrs = elem.Types(qtype)
+	if len(rrs) == 0 {
+		return []dns.RR{z.SOA}, nil, NoData
+	}
+	// Need to check sub-type on RRSIG records to only include the correctly
+	// typed ones.
+	return rrs, nil, Success
+}
+
+func (z *Zone) lookupSOA(do bool) ([]dns.RR, []dns.RR, Result) {
+	return []dns.RR{z.SOA}, nil, Success
+}
+
+// signatureForSubType range through the signature and return the correct
+// ones for the subtype.
+func (z *Zone) signatureForSubType(rrs []dns.RR, subtype uint16, do bool) []dns.RR {
+	if !do {
+		return nil
+	}
+	sigs := []dns.RR{}
+	for _, sig := range rrs {
+		if s, ok := sig.(*dns.RRSIG); ok {
+			if s.TypeCovered == subtype {
+				sigs = append(sigs, s)
+			}
+		}
+	}
+	return sigs
+}

middleware/file/lookup_test.go

+package file
+
+import (
+	"sort"
+	"strings"
+	"testing"
+
+	"github.com/miekg/coredns/middleware"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+var dnsTestCases = []dnsTestCase{
+	{
+		Qname: "miek.nl.", Qtype: dns.TypeSOA,
+		Answer: []dns.RR{
+			newSOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
+		},
+	},
+	{
+		Qname: "miek.nl.", Qtype: dns.TypeAAAA,
+		Answer: []dns.RR{
+			newAAAA("miek.nl.	1800	IN	AAAA	2a01:7e00::f03c:91ff:fef1:6735"),
+		},
+	},
+	{
+		Qname: "miek.nl.", Qtype: dns.TypeMX,
+		Answer: []dns.RR{
+			newMX("miek.nl.	1800	IN	MX	1 aspmx.l.google.com."),
+			newMX("miek.nl.	1800	IN	MX	10 aspmx2.googlemail.com."),
+			newMX("miek.nl.	1800	IN	MX	10 aspmx3.googlemail.com."),
+			newMX("miek.nl.	1800	IN	MX	5 alt1.aspmx.l.google.com."),
+			newMX("miek.nl.	1800	IN	MX	5 alt2.aspmx.l.google.com."),
+		},
+	},
+	{
+		Qname: "www.miek.nl.", Qtype: dns.TypeA,
+		Answer: []dns.RR{
+			newCNAME("www.miek.nl.	1800	IN	CNAME	a.miek.nl."),
+		},
+
+		Extra: []dns.RR{
+			newA("a.miek.nl.	1800	IN	A	139.162.196.78"),
+			newAAAA("a.miek.nl.	1800	IN	AAAA	2a01:7e00::f03c:91ff:fef1:6735"),
+		},
+	},
+	{
+		Qname: "a.miek.nl.", Qtype: dns.TypeSRV,
+		Ns: []dns.RR{
+			newSOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
+		},
+	},
+	{
+		Qname: "b.miek.nl.", Qtype: dns.TypeA,
+		Rcode: dns.RcodeNameError,
+		Ns: []dns.RR{
+			newSOA("miek.nl.	1800	IN	SOA	linode.atoom.net. miek.miek.nl. 1282630057 14400 3600 604800 14400"),
+		},
+	},
+}
+
+type rrSet []dns.RR
+
+func (p rrSet) Len() int           { return len(p) }
+func (p rrSet) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+func (p rrSet) Less(i, j int) bool { return p[i].String() < p[j].String() }
+
+const testzone = "miek.nl."
+
+func TestLookup(t *testing.T) {
+	zone, err := Parse(strings.NewReader(dbMiekNL), testzone, "stdin")
+	if err != nil {
+		t.Fatalf("expect no error when reading zone, got %q", err)
+	}
+
+	fm := File{Next: handler(), Zones: Zones{Z: map[string]*Zone{testzone: zone}, Names: []string{testzone}}}
+	ctx := context.TODO()
+
+	for _, tc := range dnsTestCases {
+		m := new(dns.Msg)
+		m.SetQuestion(dns.Fqdn(tc.Qname), tc.Qtype)
+
+		rec := middleware.NewResponseRecorder(&middleware.TestResponseWriter{})
+		_, err := fm.ServeDNS(ctx, rec, m)
+		if err != nil {
+			t.Errorf("expected no error, got %v\n", err)
+			return
+		}
+		resp := rec.Msg()
+
+		sort.Sort(rrSet(resp.Answer))
+		sort.Sort(rrSet(resp.Ns))
+		sort.Sort(rrSet(resp.Extra))
+
+		if resp.Rcode != tc.Rcode {
+			t.Errorf("rcode is %q, expected %q", dns.RcodeToString[resp.Rcode], dns.RcodeToString[tc.Rcode])
+			t.Logf("%v\n", resp)
+			continue
+		}
+
+		if len(resp.Answer) != len(tc.Answer) {
+			t.Errorf("answer for %q contained %d results, %d expected", tc.Qname, len(resp.Answer), len(tc.Answer))
+			t.Logf("%v\n", resp)
+			continue
+		}
+		if len(resp.Ns) != len(tc.Ns) {
+			t.Errorf("authority for %q contained %d results, %d expected", tc.Qname, len(resp.Ns), len(tc.Ns))
+			t.Logf("%v\n", resp)
+			continue
+		}
+		if len(resp.Extra) != len(tc.Extra) {
+			t.Errorf("additional for %q contained %d results, %d expected", tc.Qname, len(resp.Extra), len(tc.Extra))
+			t.Logf("%v\n", resp)
+			continue
+		}
+	}
+}
+
+type dnsTestCase struct {
+	Qname  string
+	Qtype  uint16
+	Rcode  int
+	Answer []dns.RR
+	Ns     []dns.RR
+	Extra  []dns.RR
+}
+
+func newA(rr string) *dns.A         { r, _ := dns.NewRR(rr); return r.(*dns.A) }
+func newAAAA(rr string) *dns.AAAA   { r, _ := dns.NewRR(rr); return r.(*dns.AAAA) }
+func newCNAME(rr string) *dns.CNAME { r, _ := dns.NewRR(rr); return r.(*dns.CNAME) }
+func newSRV(rr string) *dns.SRV     { r, _ := dns.NewRR(rr); return r.(*dns.SRV) }
+func newSOA(rr string) *dns.SOA     { r, _ := dns.NewRR(rr); return r.(*dns.SOA) }
+func newNS(rr string) *dns.NS       { r, _ := dns.NewRR(rr); return r.(*dns.NS) }
+func newPTR(rr string) *dns.PTR     { r, _ := dns.NewRR(rr); return r.(*dns.PTR) }
+func newTXT(rr string) *dns.TXT     { r, _ := dns.NewRR(rr); return r.(*dns.TXT) }
+func newMX(rr string) *dns.MX       { r, _ := dns.NewRR(rr); return r.(*dns.MX) }
+
+const dbMiekNL = `
+$TTL    30M
+$ORIGIN miek.nl.
+@       IN      SOA     linode.atoom.net. miek.miek.nl. (
+                             1282630057 ; Serial
+                             4H         ; Refresh
+                             1H         ; Retry
+                             7D         ; Expire
+                             4H )       ; Negative Cache TTL
+                IN      NS      linode.atoom.net.
+                IN      NS      ns-ext.nlnetlabs.nl.
+                IN      NS      omval.tednet.nl.
+                IN      NS      ext.ns.whyscream.net.
+
+                IN      MX      1  aspmx.l.google.com.
+                IN      MX      5  alt1.aspmx.l.google.com.
+                IN      MX      5  alt2.aspmx.l.google.com.
+                IN      MX      10 aspmx2.googlemail.com.
+                IN      MX      10 aspmx3.googlemail.com.
+
+                IN      A       139.162.196.78
+                IN      AAAA    2a01:7e00::f03c:91ff:fef1:6735
+
+a               IN      A       139.162.196.78
+                IN      AAAA    2a01:7e00::f03c:91ff:fef1:6735
+www             IN      CNAME   a
+archive         IN      CNAME   a`
+
+func handler() middleware.Handler {
+	return middleware.HandlerFunc(func(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+		m := new(dns.Msg)
+		m.SetRcode(r, dns.RcodeServerFailure)
+		w.WriteMsg(m)
+		return dns.RcodeServerFailure, nil
+	})
+}

middleware/file/zone.go

+package file
+
+import (
+	"github.com/miekg/coredns/middleware/file/tree"
+
+	"github.com/miekg/dns"
+)
+
+type Zone struct {
+	SOA  *dns.SOA
+	SIG  []*dns.RRSIG
+	name string
+	*tree.Tree
+}
+
+func NewZone(name string) *Zone {
+	return &Zone{name: dns.Fqdn(name), Tree: &tree.Tree{}}
+}
+
+func (z *Zone) Insert(r dns.RR) {
+	z.Tree.Insert(r)
+}
+
+func (z *Zone) Delete(r dns.RR) {
+	z.Tree.Delete(r)
+}

middleware/file/zone_test.go

+package file
+
+import (
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+func TestZoneInsert(t *testing.T) {
+	z := NewZone("miek.nl")
+	rr, _ := dns.NewRR("miek.nl. IN A 127.0.0.1")
+	z.Insert(rr)
+
+	t.Logf("%+v\n", z)
+
+	elem := z.Get(rr)
+	t.Logf("%+v\n", elem)
+	if elem != nil {
+		t.Logf("%+v\n", elem.Types(dns.TypeA))
+	}
+	z.Delete(rr)
+
+	t.Logf("%+v\n", z)
+
+	elem = z.Get(rr)
+	t.Logf("%+v\n", elem)
+	if elem != nil {
+		t.Logf("%+v\n", elem.Types(dns.TypeA))
+	}
+}

middleware/state.go

@@ -179,11 +179,3 @@ func (s State) ErrorMessage(rcode int) *dns.Msg {
 	m.SetRcode(s.Req, rcode)
 	return m
 }
-
-// AnswerMessage returns an error message suitable for sending
-// back to the client.
-func (s State) AnswerMessage() *dns.Msg {
-	m := new(dns.Msg)
-	m.SetReply(s.Req)
-	return m
-}