more etcd stuff

core/setup/etcd.go

@@ -8,24 +8,24 @@ import (
 	"net/http"
 	"time"
 
-	etcdc "github.com/coreos/etcd/client"
 	"github.com/miekg/coredns/middleware"
-	"github.com/miekg/coredns/middleware/file"
+	"github.com/miekg/coredns/middleware/etcd"
+
+	etcdc "github.com/coreos/etcd/client"
 )
 
-const defaultAddress = "http://127.0.0.1:2379"
+const defaultEndpoint = "http://127.0.0.1:2379"
 
 // Etcd sets up the etcd middleware.
 func Etcd(c *Controller) (middleware.Middleware, error) {
-	keysapi, err := etcdParse(c)
+	client, err := etcdParse(c)
 	if err != nil {
 		return nil, err
 	}
 
 	return func(next middleware.Handler) middleware.Handler {
-		return file.File{Next: next, Zones: zones}
+		return etcd.NewEtcd(client, next, c.ServerBlockHosts)
 	}, nil
-
 }
 
 func etcdParse(c *Controller) (etcdc.KeysAPI, error) {
@@ -33,43 +33,30 @@ func etcdParse(c *Controller) (etcdc.KeysAPI, error) {
 		if c.Val() == "etcd" {
 			// etcd [address...]
 			if !c.NextArg() {
-
+				// TODO(certs) and friends, this is client side
-				return file.Zones{}, c.ArgErr()
+				client, err := newEtcdClient([]string{defaultEndpoint}, "", "", "")
+				return client, err
 			}
-			args1 := c.RemainingArgs()
+			client, err := newEtcdClient(c.RemainingArgs(), "", "", "")
-			fileName := c.Val()
+			return client, err
-
-			origin := c.ServerBlockHosts[c.ServerBlockHostIndex]
-			if c.NextArg() {
-				c.Next()
-				origin = c.Val()
-			}
-			// normalize this origin
-			origin = middleware.Host(origin).StandardHost()
-
-			zone, err := parseZone(origin, fileName)
-			if err == nil {
-				z[origin] = zone
-			}
-			names = append(names, origin)
 		}
 	}
-	return file.Zones{Z: z, Names: names}, nil
+	return nil, nil
 }
 
-func newEtcdClient(machines []string, tlsCert, tlsKey, tlsCACert string) (etcd.KeysAPI, error) {
+func newEtcdClient(endpoints []string, tlsCert, tlsKey, tlsCACert string) (etcdc.KeysAPI, error) {
-	etcdCfg := etcd.Config{
+	etcdCfg := etcdc.Config{
-		Endpoints: machines,
+		Endpoints: endpoints,
 		Transport: newHTTPSTransport(tlsCert, tlsKey, tlsCACert),
 	}
-	cli, err := etcd.New(etcdCfg)
+	cli, err := etcdc.New(etcdCfg)
 	if err != nil {
 		return nil, err
 	}
-	return etcd.NewKeysAPI(cli), nil
+	return etcdc.NewKeysAPI(cli), nil
 }
 
-func newHTTPSTransport(tlsCertFile, tlsKeyFile, tlsCACertFile string) etcd.CancelableTransport {
+func newHTTPSTransport(tlsCertFile, tlsKeyFile, tlsCACertFile string) etcdc.CancelableTransport {
 	var cc *tls.Config = nil
 
 	if tlsCertFile != "" && tlsKeyFile != "" {

core/setup/file.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/miekg/coredns/middleware"
 	"github.com/miekg/coredns/middleware/file"
+
 	"github.com/miekg/dns"
 )
 

middleware/etcd/backend.go

@@ -1,164 +0,0 @@
-// Package etcd provides the etcd server Backend implementation,
-package etcd
-
-import (
-	"encoding/json"
-	"fmt"
-	"strings"
-
-	"github.com/miekg/coredns/middleware/etcd/msg"
-
-	etcdc "github.com/coreos/etcd/client"
-)
-
-const (
-	priority = 10   // default priority when nothing is set
-	ttl      = 3600 // default ttl when nothing is set
-)
-
-func (g *Backend) Records(name string, exact bool) ([]msg.Service, error) {
-	path, star := msg.PathWithWildcard(name)
-	r, err := g.get(path, true)
-	if err != nil {
-		return nil, err
-	}
-	segments := strings.Split(msg.Path(name), "/")
-	switch {
-	case exact && r.Node.Dir:
-		return nil, nil
-	case r.Node.Dir:
-		return g.loopNodes(r.Node.Nodes, segments, star, nil)
-	default:
-		return g.loopNodes([]*etcdc.Node{r.Node}, segments, false, nil)
-	}
-}
-
-func (g *Backend) ReverseRecord(name string) (*msg.Service, error) {
-	path, star := msg.PathWithWildcard(name)
-	if star {
-		return nil, fmt.Errorf("reverse can not contain wildcards")
-	}
-	r, err := g.get(path, true)
-	if err != nil {
-		return nil, err
-	}
-	if r.Node.Dir {
-		return nil, fmt.Errorf("reverse must not be a directory")
-	}
-	segments := strings.Split(msg.Path(name), "/")
-	records, err := g.loopNodes([]*etcdc.Node{r.Node}, segments, false, nil)
-	if err != nil {
-		return nil, err
-	}
-	if len(records) != 1 {
-		return nil, fmt.Errorf("must be only one service record")
-	}
-	return &records[0], nil
-}
-
-// get is a wrapper for client.Get that uses SingleInflight to suppress multiple
-// outstanding queries.
-func (g *Backend) get(path string, recursive bool) (*etcdc.Response, error) {
-	resp, err := g.inflight.Do(path, func() (interface{}, error) {
-		r, e := g.client.Get(g.ctx, path, &etcdc.GetOptions{Sort: false, Recursive: recursive})
-		if e != nil {
-			return nil, e
-		}
-		return r, e
-	})
-	if err != nil {
-		return nil, err
-	}
-	return resp.(*etcdc.Response), err
-}
-
-type bareService struct {
-	Host     string
-	Port     int
-	Priority int
-	Weight   int
-	Text     string
-}
-
-// skydns/local/skydns/east/staging/web
-// skydns/local/skydns/west/production/web
-//
-// skydns/local/skydns/*/*/web
-// skydns/local/skydns/*/web
-
-// loopNodes recursively loops through the nodes and returns all the values. The nodes' keyname
-// will be match against any wildcards when star is true.
-func (g *Backend) loopNodes(ns []*etcdc.Node, nameParts []string, star bool, bx map[bareService]bool) (sx []msg.Service, err error) {
-	if bx == nil {
-		bx = make(map[bareService]bool)
-	}
-Nodes:
-	for _, n := range ns {
-		if n.Dir {
-			nodes, err := g.loopNodes(n.Nodes, nameParts, star, bx)
-			if err != nil {
-				return nil, err
-			}
-			sx = append(sx, nodes...)
-			continue
-		}
-		if star {
-			keyParts := strings.Split(n.Key, "/")
-			for i, n := range nameParts {
-				if i > len(keyParts)-1 {
-					// name is longer than key
-					continue Nodes
-				}
-				if n == "*" || n == "any" {
-					continue
-				}
-				if keyParts[i] != n {
-					continue Nodes
-				}
-			}
-		}
-		serv := new(msg.Service)
-		if err := json.Unmarshal([]byte(n.Value), serv); err != nil {
-			return nil, err
-		}
-		b := bareService{serv.Host, serv.Port, serv.Priority, serv.Weight, serv.Text}
-		if _, ok := bx[b]; ok {
-			continue
-		}
-		bx[b] = true
-
-		serv.Key = n.Key
-		serv.Ttl = g.calculateTtl(n, serv)
-		if serv.Priority == 0 {
-			serv.Priority = priority
-		}
-		sx = append(sx, *serv)
-	}
-	return sx, nil
-}
-
-// calculateTtl returns the smaller of the etcd TTL and the service's
-// TTL. If neither of these are set (have a zero value), the server
-// default is used.
-func (g *Backend) calculateTtl(node *etcdc.Node, serv *msg.Service) uint32 {
-	etcdTtl := uint32(node.TTL)
-
-	if etcdTtl == 0 && serv.Ttl == 0 {
-		return ttl
-	}
-	if etcdTtl == 0 {
-		return serv.Ttl
-	}
-	if serv.Ttl == 0 {
-		return etcdTtl
-	}
-	if etcdTtl < serv.Ttl {
-		return etcdTtl
-	}
-	return serv.Ttl
-}
-
-// Client exposes the underlying Etcd client (used in tests).
-func (g *Backend) Client() etcdc.KeysAPI {
-	return g.client
-}

middleware/etcd/etcd.go

@@ -2,9 +2,12 @@
 package etcd
 
 import (
+	"encoding/json"
+	"strings"
+
 	"github.com/miekg/coredns/middleware"
-	"github.com/miekg/dns"
+	"github.com/miekg/coredns/middleware/etcd/msg"
-	"github.com/skynetservices/skydns/singleflight"
+	"github.com/miekg/coredns/middleware/etcd/singleflight"
 
 	etcdc "github.com/coreos/etcd/client"
 	"golang.org/x/net/context"
@@ -13,22 +16,135 @@ import (
 type (
 	Etcd struct {
 		Next     middleware.Handler
-
+		Zones    []string
-		client   etcd.KeysAPI
+		client   etcdc.KeysAPI
 		ctx      context.Context
 		inflight *singleflight.Group
 	}
 )
 
-func NewEtcd(client etcdc.KeysAPI, next middleware.Handler) Etcd {
+func NewEtcd(client etcdc.KeysAPI, next middleware.Handler, zones []string) Etcd {
 	return Etcd{
 		Next:     next,
+		Zones:    zones,
 		client:   client,
 		ctx:      context.Background(),
 		inflight: &singleflight.Group{},
 	}
 }
 
-func (e Etcd) ServerDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+func (g Etcd) Records(name string, exact bool) ([]msg.Service, error) {
-	return 0, nil
+	path, star := msg.PathWithWildcard(name)
+	r, err := g.Get(path, true)
+	if err != nil {
+		return nil, err
+	}
+	segments := strings.Split(msg.Path(name), "/")
+	switch {
+	case exact && r.Node.Dir:
+		return nil, nil
+	case r.Node.Dir:
+		return g.loopNodes(r.Node.Nodes, segments, star, nil)
+	default:
+		return g.loopNodes([]*etcdc.Node{r.Node}, segments, false, nil)
+	}
 }
+
+// Get is a wrapper for client.Get that uses SingleInflight to suppress multiple outstanding queries.
+func (g Etcd) Get(path string, recursive bool) (*etcdc.Response, error) {
+	resp, err := g.inflight.Do(path, func() (interface{}, error) {
+		r, e := g.client.Get(g.ctx, path, &etcdc.GetOptions{Sort: false, Recursive: recursive})
+		if e != nil {
+			return nil, e
+		}
+		return r, e
+	})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*etcdc.Response), err
+}
+
+// skydns/local/skydns/east/staging/web
+// skydns/local/skydns/west/production/web
+//
+// skydns/local/skydns/*/*/web
+// skydns/local/skydns/*/web
+
+// loopNodes recursively loops through the nodes and returns all the values. The nodes' keyname
+// will be match against any wildcards when star is true.
+func (g Etcd) loopNodes(ns []*etcdc.Node, nameParts []string, star bool, bx map[msg.Service]bool) (sx []msg.Service, err error) {
+	if bx == nil {
+		bx = make(map[msg.Service]bool)
+	}
+Nodes:
+	for _, n := range ns {
+		if n.Dir {
+			nodes, err := g.loopNodes(n.Nodes, nameParts, star, bx)
+			if err != nil {
+				return nil, err
+			}
+			sx = append(sx, nodes...)
+			continue
+		}
+		if star {
+			keyParts := strings.Split(n.Key, "/")
+			for i, n := range nameParts {
+				if i > len(keyParts)-1 {
+					// name is longer than key
+					continue Nodes
+				}
+				if n == "*" || n == "any" {
+					continue
+				}
+				if keyParts[i] != n {
+					continue Nodes
+				}
+			}
+		}
+		serv := new(msg.Service)
+		if err := json.Unmarshal([]byte(n.Value), serv); err != nil {
+			return nil, err
+		}
+		b := msg.Service{Host: serv.Host, Port: serv.Port, Priority: serv.Priority, Weight: serv.Weight, Text: serv.Text}
+		if _, ok := bx[b]; ok {
+			continue
+		}
+		bx[b] = true
+
+		serv.Key = n.Key
+		serv.Ttl = g.Ttl(n, serv)
+		if serv.Priority == 0 {
+			serv.Priority = priority
+		}
+		sx = append(sx, *serv)
+	}
+	return sx, nil
+}
+
+// Ttl returns the smaller of the etcd TTL and the service's
+// TTL. If neither of these are set (have a zero value), a default is used.
+func (g Etcd) Ttl(node *etcdc.Node, serv *msg.Service) uint32 {
+	etcdTtl := uint32(node.TTL)
+
+	if etcdTtl == 0 && serv.Ttl == 0 {
+		return ttl
+	}
+	if etcdTtl == 0 {
+		return serv.Ttl
+	}
+	if serv.Ttl == 0 {
+		return etcdTtl
+	}
+	if etcdTtl < serv.Ttl {
+		return etcdTtl
+	}
+	return serv.Ttl
+}
+
+const (
+	priority   = 10  // default priority when nothing is set
+	ttl        = 300 // default ttl when nothing is set
+	minTtl     = 60
+	hostmaster = "hostmaster"
+)

middleware/etcd/etcd.md

@@ -2,7 +2,10 @@
 
 `etcd` enabled reading zone data from an etcd instance. The data in etcd has to be encoded as
 a [message](https://github.com/skynetservices/skydns/blob/2fcff74cdc9f9a7dd64189a447ef27ac354b725f/msg/service.go#L26)
-like SkyDNS.
+like [SkyDNS](https//github.com/skynetservices/skydns).
+
+If you need replies to SOA and NS queries you should add a little zone after etcd directive that has
+these resource records.
 
 ## Syntax
 
@@ -14,16 +17,16 @@ etcd [endpoint...]
 
 The will default to `/skydns` as the path and the local etcd proxy (http://127.0.0.1:2379).
 
+If you want to `round robin` A and AAAA responses look at the `round_robin` middleware.
+
 ~~~
 etcd {
-    round_robin
     path /skydns
     endpoint address...
     stubzones
 }
 ~~~
 
-* `round_robin`
 * `path` /skydns
 * `endpoint` address...
 * `stubzones`

middleware/etcd/handler.go

@@ -0,0 +1,105 @@
+package etcd
+
+import (
+	"github.com/miekg/coredns/middleware"
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+func (e Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	println("ETCD MIDDLEWARE HIT")
+
+	state := middleware.State{W: w, Req: r}
+
+	m := state.AnswerMessage()
+	m.Authoritative = true
+	m.RecursionAvailable = true
+	m.Compress = true
+
+	return 0, nil
+}
+
+// only needs state and current zone name we are auth for.
+/*
+func (s *server) ServeDNS(w dns.ResponseWriter, req *dns.Msg) {
+
+	q := req.Question[0]
+	name := strings.ToLower(q.Name)
+
+	switch q.Qtype {
+	case dns.TypeNS:
+		records, extra, err := s.NSRecords(q, s.config.dnsDomain)
+		if isEtcdNameError(err, s) {
+			m = s.NameError(req)
+			return
+		}
+		m.Answer = append(m.Answer, records...)
+		m.Extra = append(m.Extra, extra...)
+	case dns.TypeA, dns.TypeAAAA:
+		records, err := s.AddressRecords(q, name, nil, bufsize, dnssec, false)
+		if isEtcdNameError(err, s) {
+			m = s.NameError(req)
+			return
+		}
+		m.Answer = append(m.Answer, records...)
+	case dns.TypeTXT:
+		records, err := s.TXTRecords(q, name)
+		if isEtcdNameError(err, s) {
+			m = s.NameError(req)
+			return
+		}
+		m.Answer = append(m.Answer, records...)
+	case dns.TypeCNAME:
+		records, err := s.CNAMERecords(q, name)
+		if isEtcdNameError(err, s) {
+			m = s.NameError(req)
+			return
+		}
+		m.Answer = append(m.Answer, records...)
+	case dns.TypeMX:
+		records, extra, err := s.MXRecords(q, name, bufsize, dnssec)
+		if isEtcdNameError(err, s) {
+			m = s.NameError(req)
+			return
+		}
+		m.Answer = append(m.Answer, records...)
+		m.Extra = append(m.Extra, extra...)
+	default:
+		fallthrough // also catch other types, so that they return NODATA
+	case dns.TypeSRV:
+		records, extra, err := s.SRVRecords(q, name, bufsize, dnssec)
+		if err != nil {
+			if isEtcdNameError(err, s) {
+				m = s.NameError(req)
+				return
+			}
+			logf("got error from backend: %s", err)
+			if q.Qtype == dns.TypeSRV { // Otherwise NODATA
+				m = s.ServerFailure(req)
+				return
+			}
+		}
+		// if we are here again, check the types, because an answer may only
+		// be given for SRV. All other types should return NODATA, the
+		// NXDOMAIN part is handled in the above code. TODO(miek): yes this
+		// can be done in a more elegant manor.
+		if q.Qtype == dns.TypeSRV {
+			m.Answer = append(m.Answer, records...)
+			m.Extra = append(m.Extra, extra...)
+		}
+	}
+
+	if len(m.Answer) == 0 { // NODATA response
+		m.Ns = []dns.RR{s.NewSOA()}
+		m.Ns[0].Header().Ttl = s.config.MinTtl
+	}
+}
+
+// etcNameError checks if the error is ErrorCodeKeyNotFound from etcd.
+func isEtcdNameError(err error, s *server) bool {
+	if e, ok := err.(etcd.Error); ok && e.Code == etcd.ErrorCodeKeyNotFound {
+		return true
+	}
+	return false
+}
+*/

middleware/etcd/lookup.go

@@ -0,0 +1,327 @@
+package etcd
+
+/*
+func (s *server) AddressRecords(q dns.Question, name string, previousRecords []dns.RR, state middleware.State) (records []dns.RR, err error) {
+	services, err := s.backend.Records(name, false)
+	if err != nil {
+		return nil, err
+	}
+
+	services = msg.Group(services)
+
+	for _, serv := range services {
+		ip := net.ParseIP(serv.Host)
+		switch {
+		case ip == nil:
+			// Try to resolve as CNAME if it's not an IP, but only if we don't create loops.
+			if q.Name == dns.Fqdn(serv.Host) {
+				// x CNAME x is a direct loop, don't add those
+				continue
+			}
+
+			newRecord := serv.NewCNAME(q.Name, dns.Fqdn(serv.Host))
+			if len(previousRecords) > 7 {
+				logf("CNAME lookup limit of 8 exceeded for %s", newRecord)
+				// don't add it, and just continue
+				continue
+			}
+			if s.isDuplicateCNAME(newRecord, previousRecords) {
+				logf("CNAME loop detected for record %s", newRecord)
+				continue
+			}
+
+			nextRecords, err := s.AddressRecords(dns.Question{Name: dns.Fqdn(serv.Host), Qtype: q.Qtype, Qclass: q.Qclass},
+				strings.ToLower(dns.Fqdn(serv.Host)), append(previousRecords, newRecord), state)
+			if err == nil {
+				// Only have we found something we should add the CNAME and the IP addresses.
+				if len(nextRecords) > 0 {
+					records = append(records, newRecord)
+					records = append(records, nextRecords...)
+				}
+				continue
+			}
+			// This means we can not complete the CNAME, try to look else where.
+			target := newRecord.Target
+			if dns.IsSubDomain(s.config.Domain, target) {
+				// We should already have found it
+				continue
+			}
+			m1, e1 := s.Lookup(target, q.Qtype, bufsize, dnssec)
+			if e1 != nil {
+				logf("incomplete CNAME chain: %s", e1)
+				continue
+			}
+			// Len(m1.Answer) > 0 here is well?
+			records = append(records, newRecord)
+			records = append(records, m1.Answer...)
+			continue
+		case ip.To4() != nil && (q.Qtype == dns.TypeA || both):
+			records = append(records, serv.NewA(q.Name, ip.To4()))
+		case ip.To4() == nil && (q.Qtype == dns.TypeAAAA || both):
+			records = append(records, serv.NewAAAA(q.Name, ip.To16()))
+		}
+	}
+	return records, nil
+}
+
+// NSRecords returns NS records from etcd.
+func (s *server) NSRecords(q dns.Question, state middleware.State) (records []dns.RR, extra []dns.RR, err error) {
+	services, err := s.backend.Records(name, false)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	services = msg.Group(services)
+
+	for _, serv := range services {
+		ip := net.ParseIP(serv.Host)
+		switch {
+		case ip == nil:
+			return nil, nil, fmt.Errorf("NS record must be an IP address")
+		case ip.To4() != nil:
+			serv.Host = msg.Domain(serv.Key)
+			records = append(records, serv.NewNS(q.Name, serv.Host))
+			extra = append(extra, serv.NewA(serv.Host, ip.To4()))
+		case ip.To4() == nil:
+			serv.Host = msg.Domain(serv.Key)
+			records = append(records, serv.NewNS(q.Name, serv.Host))
+			extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
+		}
+	}
+	return records, extra, nil
+}
+
+// SRVRecords returns SRV records from etcd.
+// If the Target is not a name but an IP address, a name is created.
+func (s *server) SRVRecords(s middleware.State) (records []dns.RR, extra []dns.RR, err error) {
+	services, err := s.backend.Records(name, false)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	services = msg.Group(services)
+
+	// Looping twice to get the right weight vs priority
+	w := make(map[int]int)
+	for _, serv := range services {
+		weight := 100
+		if serv.Weight != 0 {
+			weight = serv.Weight
+		}
+		if _, ok := w[serv.Priority]; !ok {
+			w[serv.Priority] = weight
+			continue
+		}
+		w[serv.Priority] += weight
+	}
+	lookup := make(map[string]bool)
+	for _, serv := range services {
+		w1 := 100.0 / float64(w[serv.Priority])
+		if serv.Weight == 0 {
+			w1 *= 100
+		} else {
+			w1 *= float64(serv.Weight)
+		}
+		weight := uint16(math.Floor(w1))
+		ip := net.ParseIP(serv.Host)
+		switch {
+		case ip == nil:
+			srv := serv.NewSRV(q.Name, weight)
+			records = append(records, srv)
+
+			if _, ok := lookup[srv.Target]; ok {
+				break
+			}
+
+			lookup[srv.Target] = true
+
+			if !dns.IsSubDomain(s.config.Domain, srv.Target) {
+				m1, e1 := s.Lookup(srv.Target, dns.TypeA, bufsize, dnssec)
+				if e1 == nil {
+					extra = append(extra, m1.Answer...)
+				}
+				m1, e1 = s.Lookup(srv.Target, dns.TypeAAAA, bufsize, dnssec)
+				if e1 == nil {
+					// If we have seen CNAME's we *assume* that they are already added.
+					for _, a := range m1.Answer {
+						if _, ok := a.(*dns.CNAME); !ok {
+							extra = append(extra, a)
+						}
+					}
+				}
+				break
+			}
+			// Internal name, we should have some info on them, either v4 or v6
+			// Clients expect a complete answer, because we are a recursor in their
+			// view.
+			addr, e1 := s.AddressRecords(dns.Question{srv.Target, dns.ClassINET, dns.TypeA},
+				srv.Target, nil, bufsize, dnssec, true)
+			if e1 == nil {
+				extra = append(extra, addr...)
+			}
+		case ip.To4() != nil:
+			serv.Host = msg.Domain(serv.Key)
+			srv := serv.NewSRV(q.Name, weight)
+
+			records = append(records, srv)
+			extra = append(extra, serv.NewA(srv.Target, ip.To4()))
+		case ip.To4() == nil:
+			serv.Host = msg.Domain(serv.Key)
+			srv := serv.NewSRV(q.Name, weight)
+
+			records = append(records, srv)
+			extra = append(extra, serv.NewAAAA(srv.Target, ip.To16()))
+		}
+	}
+	return records, extra, nil
+}
+
+// MXRecords returns MX records from etcd.
+// If the Target is not a name but an IP address, a name is created.
+func (s *server) MXRecords(q dns.Question, name string, s middleware.State) (records []dns.RR, extra []dns.RR, err error) {
+	services, err := s.backend.Records(name, false)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	lookup := make(map[string]bool)
+	for _, serv := range services {
+		if !serv.Mail {
+			continue
+		}
+		ip := net.ParseIP(serv.Host)
+		switch {
+		case ip == nil:
+			mx := serv.NewMX(q.Name)
+			records = append(records, mx)
+			if _, ok := lookup[mx.Mx]; ok {
+				break
+			}
+
+			lookup[mx.Mx] = true
+
+			if !dns.IsSubDomain(s.config.Domain, mx.Mx) {
+				m1, e1 := s.Lookup(mx.Mx, dns.TypeA, bufsize, dnssec)
+				if e1 == nil {
+					extra = append(extra, m1.Answer...)
+				}
+				m1, e1 = s.Lookup(mx.Mx, dns.TypeAAAA, bufsize, dnssec)
+				if e1 == nil {
+					// If we have seen CNAME's we *assume* that they are already added.
+					for _, a := range m1.Answer {
+						if _, ok := a.(*dns.CNAME); !ok {
+							extra = append(extra, a)
+						}
+					}
+				}
+				break
+			}
+			// Internal name
+			addr, e1 := s.AddressRecords(dns.Question{mx.Mx, dns.ClassINET, dns.TypeA},
+				mx.Mx, nil, bufsize, dnssec, true)
+			if e1 == nil {
+				extra = append(extra, addr...)
+			}
+		case ip.To4() != nil:
+			serv.Host = msg.Domain(serv.Key)
+			records = append(records, serv.NewMX(q.Name))
+			extra = append(extra, serv.NewA(serv.Host, ip.To4()))
+		case ip.To4() == nil:
+			serv.Host = msg.Domain(serv.Key)
+			records = append(records, serv.NewMX(q.Name))
+			extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
+		}
+	}
+	return records, extra, nil
+}
+
+func (s *server) CNAMERecords(q dns.Question, state middleware.State) (records []dns.RR, err error) {
+	services, err := s.backend.Records(name, true)
+	if err != nil {
+		return nil, err
+	}
+
+	services = msg.Group(services)
+
+	if len(services) > 0 {
+		serv := services[0]
+		if ip := net.ParseIP(serv.Host); ip == nil {
+			records = append(records, serv.NewCNAME(q.Name, dns.Fqdn(serv.Host)))
+		}
+	}
+	return records, nil
+}
+
+func (s *server) TXTRecords(q dns.Question, state middleware.State) (records []dns.RR, err error) {
+	services, err := s.backend.Records(name, false)
+	if err != nil {
+		return nil, err
+	}
+
+	services = msg.Group(services)
+
+	for _, serv := range services {
+		if serv.Text == "" {
+			continue
+		}
+		records = append(records, serv.NewTXT(q.Name))
+	}
+	return records, nil
+}
+
+func isDuplicateCNAME(r *dns.CNAME, records []dns.RR) bool {
+	for _, rec := range records {
+		if v, ok := rec.(*dns.CNAME); ok {
+			if v.Target == r.Target {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// Move to state.go somehow?
+func (s *server) NameError(req *dns.Msg) *dns.Msg {
+	m := new(dns.Msg)
+	m.SetRcode(req, dns.RcodeNameError)
+	m.Ns = []dns.RR{s.NewSOA()}
+	m.Ns[0].Header().Ttl = s.config.MinTtl
+	return m
+}
+
+// overflowOrTruncated writes back an error to the client if the message does not fit.
+// It updates prometheus metrics. If something has been written to the client, true
+// will be returned.
+func (s *server) overflowOrTruncated(w dns.ResponseWriter, m *dns.Msg, bufsize int, sy metrics.System) bool {
+	switch isTCP(w) {
+	case true:
+		if _, overflow := Fit(m, dns.MaxMsgSize, true); overflow {
+			metrics.ReportErrorCount(m, sy)
+			msgFail := s.ServerFailure(m)
+			w.WriteMsg(msgFail)
+			return true
+		}
+	case false:
+		// Overflow with udp always results in TC.
+		Fit(m, bufsize, false)
+		metrics.ReportErrorCount(m, sy)
+		if m.Truncated {
+			w.WriteMsg(m)
+			return true
+		}
+	}
+	return false
+}
+
+// etcNameError return a NameError to the client if the error
+// returned from etcd has ErrorCode == 100.
+func isEtcdNameError(err error, s *server) bool {
+	if e, ok := err.(etcd.Error); ok && e.Code == etcd.ErrorCodeKeyNotFound {
+		return true
+	}
+	if err != nil {
+		logf("error from backend: %s", err)
+	}
+	return false
+}
+*/

middleware/exchange.go

@@ -8,3 +8,7 @@ func Exchange(c *dns.Client, m *dns.Msg, server string) (*dns.Msg, error) {
 	r, _, err := c.Exchange(m, server)
 	return r, err
 }
+
+// Lookup functions, ala
+// LookupHost
+// LookupCNAME

middleware/state.go

@@ -83,6 +83,30 @@ func (s State) Family() int {
 	return 2
 }
 
+// Do returns if the request has the DO (DNSSEC OK) bit set.
+func (s State) Do() bool {
+	if o := s.Req.IsEdns0(); o != nil {
+		return o.Do()
+	}
+	return false
+}
+
+// UDPSize returns if UDP buffer size advertised in the requests OPT record.
+// Or when the request was over TCP, we return the maximum allowed size of 64K.
+func (s State) Size() int {
+	if s.Proto() == "tcp" {
+		return dns.MaxMsgSize
+	}
+	if o := s.Req.IsEdns0(); o != nil {
+		s := o.UDPSize()
+		if s < dns.MinMsgSize {
+			s = dns.MinMsgSize
+		}
+		return int(s)
+	}
+	return dns.MinMsgSize
+}
+
 // Type returns the type of the question as a string.
 func (s State) Type() string {
 	return dns.Type(s.Req.Question[0].Qtype).String()