Enable extension options

Author: Marc Odermatt

pkg/snet/packet.go

@@ -360,6 +360,10 @@ func (r RawPath) SetPath(s *slayers.SCION) error {
 	return serrors.New("snet.RawPath does not support SetPath")
 }
 
+func (r RawPath) SetExtensions(s *slayers.SCION, p *PacketInfo) error {
+	return serrors.New("snet.RawPath does not support SetExtensions")
+}
+
 // Packet describes a SCION packet.
 type Packet struct {
 	Bytes
@@ -370,16 +374,16 @@ type Packet struct {
 func (p *Packet) Decode() error {
 	var (
 		scionLayer slayers.SCION
-		hbhLayer   slayers.HopByHopExtnSkipper
-		e2eLayer   slayers.EndToEndExtnSkipper
+		hbhLayer   slayers.HopByHopExtn
+		e2eLayer   slayers.EndToEndExtn
 		udpLayer   slayers.UDP
 		scmpLayer  slayers.SCMP
 	)
 	parser := gopacket.NewDecodingLayerParser(
 		slayers.LayerTypeSCION, &scionLayer, &hbhLayer, &e2eLayer, &udpLayer, &scmpLayer,
 	)
 	parser.IgnoreUnsupported = true
-	decoded := make([]gopacket.LayerType, 0, 4)
+	decoded := make([]gopacket.LayerType, 0, 6)
 	if err := parser.DecodeLayers(p.Bytes, &decoded); err != nil {
 		return err
 	}
@@ -411,6 +415,12 @@ func (p *Packet) Decode() error {
 		}
 	}
 	p.Path = rpath
+	if len(hbhLayer.Options) != 0 {
+		p.HbhExtension = &hbhLayer
+	}
+	if len(e2eLayer.Options) != 0 {
+		p.E2eExtension = &e2eLayer
+	}
 
 	switch l4 {
 	case slayers.LayerTypeSCIONUDP:
@@ -581,10 +591,36 @@ func (p *Packet) Serialize() error {
 	if err := p.Path.SetPath(&scionLayer); err != nil {
 		return serrors.WrapStr("setting path", err)
 	}
+	if err := p.Path.SetExtensions(&scionLayer, &p.PacketInfo); err != nil {
+		return serrors.WrapStr("error setting the header extensions", err)
+	}
 
 	packetLayers = append(packetLayers, &scionLayer)
+	if p.HbhExtension != nil {
+		packetLayers = append(packetLayers, p.HbhExtension)
+	}
+	if p.E2eExtension != nil {
+		packetLayers = append(packetLayers, p.E2eExtension)
+	}
+
 	packetLayers = append(packetLayers, p.Payload.toLayers(&scionLayer)...)
 
+	if p.HbhExtension != nil {
+		tmp := scionLayer.NextHdr
+		scionLayer.NextHdr = slayers.HopByHopClass
+		p.HbhExtension.NextHdr = tmp
+
+		if p.E2eExtension != nil {
+			tmp = p.HbhExtension.NextHdr
+			p.HbhExtension.NextHdr = slayers.End2EndClass
+			p.E2eExtension.NextHdr = tmp
+		}
+	} else if p.E2eExtension != nil {
+		tmp := scionLayer.NextHdr
+		scionLayer.NextHdr = slayers.End2EndClass
+		p.E2eExtension.NextHdr = tmp
+	}
+
 	buffer := gopacket.NewSerializeBuffer()
 	options := gopacket.SerializeOptions{
 		ComputeChecksums: true,
@@ -617,4 +653,8 @@ type PacketInfo struct {
 	Path DataplanePath
 	// Payload is the Payload of the message.
 	Payload Payload
+	// HbhExtension contains the Hop-by-Hop options.
+	HbhExtension *slayers.HopByHopExtn
+	// E2eExtension contains the End-to-End options.
+	E2eExtension *slayers.EndToEndExtn
 }

pkg/snet/path.go

@@ -41,6 +41,8 @@ type DataplanePath interface {
 	// SetPath sets the path in the SCION header. It assumes that all the fields
 	// except the path and path type are set correctly.
 	SetPath(scion *slayers.SCION) error
+
+	SetExtensions(s *slayers.SCION, p *PacketInfo) error
 }
 
 // Path is an abstract representation of a path. Most applications do not need

pkg/snet/path/empty.go

@@ -17,6 +17,7 @@ package path
 import (
 	"github.com/scionproto/scion/pkg/slayers"
 	"github.com/scionproto/scion/pkg/slayers/path/empty"
+	"github.com/scionproto/scion/pkg/snet"
 )
 
 type Empty struct{}
@@ -25,3 +26,7 @@ func (e Empty) SetPath(s *slayers.SCION) error {
 	s.Path, s.PathType = empty.Path{}, empty.PathType
 	return nil
 }
+
+func (e Empty) SetExtensions(s *slayers.SCION, p *snet.PacketInfo) error {
+	return nil
+}

pkg/snet/path/epic.go

@@ -94,3 +94,7 @@ func (e *EPIC) SetPath(s *slayers.SCION) error {
 	s.Path, s.PathType = ep, ep.Type()
 	return nil
 }
+
+func (e *EPIC) SetExtensions(s *slayers.SCION, p *snet.PacketInfo) error {
+	return nil
+}

pkg/snet/path/onehop.go

@@ -16,6 +16,7 @@ package path
 
 import (
 	"crypto/rand"
+	"github.com/scionproto/scion/pkg/snet"
 	"hash"
 	"math/big"
 	"time"
@@ -68,3 +69,7 @@ func NewOneHop(
 	ohp.FirstHop.Mac = path.MAC(mac, ohp.Info, ohp.FirstHop, nil)
 	return ohp, nil
 }
+
+func (p OneHop) SetExtensions(s *slayers.SCION, pi *snet.PacketInfo) error {
+	return nil
+}

pkg/snet/path/scion.go

@@ -18,6 +18,7 @@ import (
 	"github.com/scionproto/scion/pkg/private/serrors"
 	"github.com/scionproto/scion/pkg/slayers"
 	"github.com/scionproto/scion/pkg/slayers/path/scion"
+	"github.com/scionproto/scion/pkg/snet"
 )
 
 type SCION struct {
@@ -43,3 +44,7 @@ func (p SCION) SetPath(s *slayers.SCION) error {
 	s.Path, s.PathType = &sp, sp.Type()
 	return nil
 }
+
+func (p SCION) SetExtensions(s *slayers.SCION, pi *snet.PacketInfo) error {
+	return nil
+}

pkg/snet/reply_pather.go

@@ -58,3 +58,7 @@ func (p RawReplyPath) SetPath(s *slayers.SCION) error {
 	s.Path, s.PathType = p.Path, p.Path.Type()
 	return nil
 }
+
+func (p RawReplyPath) SetExtensions(s *slayers.SCION, pi *PacketInfo) error {
+	return nil
+}