plugin/dnstap: various cleanups (#4179)

* plugin/dnstap: various cleanups

A recent issue made me look into this plugin, I suspect various other
cleanups (hopefully deletion of code) can be made as well

Remove identical functions ToClientQuery etc, and just use tap.Message
as the base type in plugin. Keep msg/ for a few helper functions that
may proof useful.

This remove the whole test directory as we will just check the things we
are interested in which gives much better feedback and keeps that code
closer together.

tapwr dir is also not needed, writer_test.go was just duplicating the
tests already done. This moves writer.go to the top directory.

Make the only user of dnstap, the forward plugin, use the newer code
also remove the test, a better test there would be a full e2e test to
see the correct thing happens.

Cleanup the Tapper interface and move it to dnstapio where it belongs,
remove higher level interfaces that are not used. This remove
dnstap.Tapper and dnstap.IORoutines.

Use the standard mechanism for getting access to a plugin and remove
shuffling the plugin into the context.

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

* use opts to get the correct proto

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

* Various fixes

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

* Remove bad addr test, as dnstap is only called from within coredns where these fields have been preparsed

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

* dnstap: remove saving the error

all these fields have been preparsed, no need for dnstap to be pedantic
and check (and save!) this error again.

Simplifies it a bit more.

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

* Update plugin/forward/dnstap.go

Co-authored-by: Ruslan Drozhdzh <30860269+rdrozhdzh@users.noreply.github.com>

* Code review

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

* add back in preferUDP

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

* nit

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

Co-authored-by: Ruslan Drozhdzh <30860269+rdrozhdzh@users.noreply.github.com>

1 files changed, 69 insertions, 131 deletions

diff --git a/plugin/dnstap/msg/msg.go b/plugin/dnstap/msg/msg.go
index d96fc6c9a..f9d84c45a 100644
--- a/plugin/dnstap/msg/msg.go
+++ b/plugin/dnstap/msg/msg.go
@@ -1,159 +1,97 @@
 package msg
 
 import (
-	"errors"
+	"fmt"
 	"net"
-	"strconv"
 	"time"
 
 	tap "github.com/dnstap/golang-dnstap"
-	"github.com/miekg/dns"
 )
 
-// Builder helps to build a Dnstap message.
-type Builder struct {
-	Packed      []byte
-	SocketProto tap.SocketProtocol
-	SocketFam   tap.SocketFamily
-	Address     net.IP
-	Port        uint32
-	TimeSec     uint64
-	TimeNsec    uint32
-
-	err error
-}
+var (
+	protoUDP    = tap.SocketProtocol_UDP
+	protoTCP    = tap.SocketProtocol_TCP
+	familyINET  = tap.SocketFamily_INET
+	familyINET6 = tap.SocketFamily_INET6
+)
 
-// New returns a new Builder
-func New() *Builder {
-	return &Builder{}
-}
+// SetQueryAddress adds the query address to the message. This also sets the SocketFamily and SocketProtocol.
+func SetQueryAddress(t *tap.Message, addr net.Addr) error {
+	t.SocketFamily = &familyINET
+	switch a := addr.(type) {
+	case *net.TCPAddr:
+		t.SocketProtocol = &protoTCP
+		t.QueryAddress = a.IP
 
-// Addr adds the remote address to the message.
-func (b *Builder) Addr(remote net.Addr) *Builder {
-	if b.err != nil {
-		return b
-	}
+		p := uint32(a.Port)
+		t.QueryPort = &p
 
-	switch addr := remote.(type) {
-	case *net.TCPAddr:
-		b.Address = addr.IP
-		b.Port = uint32(addr.Port)
-		b.SocketProto = tap.SocketProtocol_TCP
+		if a.IP.To4() == nil {
+			t.SocketFamily = &familyINET6
+		}
+		return nil
 	case *net.UDPAddr:
-		b.Address = addr.IP
-		b.Port = uint32(addr.Port)
-		b.SocketProto = tap.SocketProtocol_UDP
-	default:
-		b.err = errors.New("unknown remote address type")
-		return b
-	}
+		t.SocketProtocol = &protoUDP
+		t.QueryAddress = a.IP
+
+		p := uint32(a.Port)
+		t.QueryPort = &p
 
-	if b.Address.To4() != nil {
-		b.SocketFam = tap.SocketFamily_INET
-	} else {
-		b.SocketFam = tap.SocketFamily_INET6
+		if a.IP.To4() == nil {
+			t.SocketFamily = &familyINET6
+		}
+		return nil
+	default:
+		return fmt.Errorf("unknown address type: %T", a)
 	}
-	return b
 }
 
-// Msg adds the raw DNS message to the dnstap message.
-func (b *Builder) Msg(m *dns.Msg) *Builder {
-	if b.err != nil {
-		return b
-	}
+// SetResponseAddress the response address to the message. This also sets the SocketFamily and SocketProtocol.
+func SetResponseAddress(t *tap.Message, addr net.Addr) error {
+	t.SocketFamily = &familyINET
+	switch a := addr.(type) {
+	case *net.TCPAddr:
+		t.SocketProtocol = &protoTCP
+		t.ResponseAddress = a.IP
 
-	b.Packed, b.err = m.Pack()
-	return b
-}
+		p := uint32(a.Port)
+		t.ResponsePort = &p
 
-// HostPort adds the remote address as encoded by dnsutil.ParseHostPortOrFile to the message.
-func (b *Builder) HostPort(addr string) *Builder {
-	ip, port, err := net.SplitHostPort(addr)
-	if err != nil {
-		b.err = err
-		return b
-	}
-	p, err := strconv.ParseUint(port, 10, 32)
-	if err != nil {
-		b.err = err
-		return b
-	}
-	b.Port = uint32(p)
-
-	if ip := net.ParseIP(ip); ip != nil {
-		b.Address = []byte(ip)
-		if ip := ip.To4(); ip != nil {
-			b.SocketFam = tap.SocketFamily_INET
-		} else {
-			b.SocketFam = tap.SocketFamily_INET6
+		if a.IP.To4() == nil {
+			t.SocketFamily = &familyINET6
 		}
-		return b
-	}
-	b.err = errors.New("not an ip address")
-	return b
-}
+		return nil
+	case *net.UDPAddr:
+		t.SocketProtocol = &protoUDP
+		t.ResponseAddress = a.IP
 
-// Time adds the timestamp to the message.
-func (b *Builder) Time(ts time.Time) *Builder {
-	b.TimeSec = uint64(ts.Unix())
-	b.TimeNsec = uint32(ts.Nanosecond())
-	return b
-}
+		p := uint32(a.Port)
+		t.ResponsePort = &p
 
-// ToClientResponse transforms Data into a client response message.
-func (b *Builder) ToClientResponse() (*tap.Message, error) {
-	t := tap.Message_CLIENT_RESPONSE
-	return &tap.Message{
-		Type:             &t,
-		SocketFamily:     &b.SocketFam,
-		SocketProtocol:   &b.SocketProto,
-		ResponseTimeSec:  &b.TimeSec,
-		ResponseTimeNsec: &b.TimeNsec,
-		ResponseMessage:  b.Packed,
-		QueryAddress:     b.Address,
-		QueryPort:        &b.Port,
-	}, b.err
+		if a.IP.To4() == nil {
+			t.SocketFamily = &familyINET6
+		}
+		return nil
+	default:
+		return fmt.Errorf("unknown address type: %T", a)
+	}
 }
 
-// ToClientQuery transforms Data into a client query message.
-func (b *Builder) ToClientQuery() (*tap.Message, error) {
-	t := tap.Message_CLIENT_QUERY
-	return &tap.Message{
-		Type:           &t,
-		SocketFamily:   &b.SocketFam,
-		SocketProtocol: &b.SocketProto,
-		QueryTimeSec:   &b.TimeSec,
-		QueryTimeNsec:  &b.TimeNsec,
-		QueryMessage:   b.Packed,
-		QueryAddress:   b.Address,
-		QueryPort:      &b.Port,
-	}, b.err
+// SetQueryTime sets the time of the query in t.
+func SetQueryTime(t *tap.Message, ti time.Time) {
+	qts := uint64(ti.Unix())
+	qtn := uint32(ti.Nanosecond())
+	t.QueryTimeSec = &qts
+	t.QueryTimeNsec = &qtn
 }
 
-// ToOutsideQuery transforms the data into a forwarder or resolver query message.
-func (b *Builder) ToOutsideQuery(t tap.Message_Type) (*tap.Message, error) {
-	return &tap.Message{
-		Type:            &t,
-		SocketFamily:    &b.SocketFam,
-		SocketProtocol:  &b.SocketProto,
-		QueryTimeSec:    &b.TimeSec,
-		QueryTimeNsec:   &b.TimeNsec,
-		QueryMessage:    b.Packed,
-		ResponseAddress: b.Address,
-		ResponsePort:    &b.Port,
-	}, b.err
+// SetResponseTime sets the time of the response in t.
+func SetResponseTime(t *tap.Message, ti time.Time) {
+	rts := uint64(ti.Unix())
+	rtn := uint32(ti.Nanosecond())
+	t.ResponseTimeSec = &rts
+	t.ResponseTimeNsec = &rtn
 }
 
-// ToOutsideResponse transforms the data into a forwarder or resolver response message.
-func (b *Builder) ToOutsideResponse(t tap.Message_Type) (*tap.Message, error) {
-	return &tap.Message{
-		Type:             &t,
-		SocketFamily:     &b.SocketFam,
-		SocketProtocol:   &b.SocketProto,
-		ResponseTimeSec:  &b.TimeSec,
-		ResponseTimeNsec: &b.TimeNsec,
-		ResponseMessage:  b.Packed,
-		ResponseAddress:  b.Address,
-		ResponsePort:     &b.Port,
-	}, b.err
-}
+// SetType sets the type in t.
+func SetType(t *tap.Message, typ tap.Message_Type) { t.Type = &typ }