snet: Copy method added to snet.Path (#3226)

go/lib/infra/messenger/addr_test.go

@@ -498,3 +498,7 @@ func (t *testPath) Destination() addr.IA {
 func (t *testPath) MTU() uint16 {
 	panic("not implemented")
 }
+
+func (t *testPath) Copy() snet.Path {
+	panic("not implemented")
+}

go/lib/overlay/addr.go

@@ -72,6 +72,9 @@ func (a *OverlayAddr) Type() Type {
 }
 
 func (a *OverlayAddr) Copy() *OverlayAddr {
+	if a == nil {
+		return nil
+	}
 	return &OverlayAddr{l3: a.l3.Copy(), l4: a.l4.Copy()}
 }
 

go/lib/snet/router.go

@@ -135,6 +135,8 @@ type Path interface {
 	Destination() addr.IA
 	// MTU returns the MTU of the path. If the result is zero, MTU is unknown.
 	MTU() uint16
+	// Copy create a copy of the path.
+	Copy() Path
 }
 
 var _ Path = (*path)(nil)
@@ -159,7 +161,7 @@ func (p *path) Fingerprint() string {
 }
 
 func (p *path) OverlayNextHop() *overlay.OverlayAddr {
-	return p.overlay
+	return p.overlay.Copy()
 }
 
 func (p *path) Path() *spath.Path {
@@ -183,6 +185,15 @@ func (p *path) MTU() uint16 {
 	return p.sciondPath.Path.Mtu
 }
 
+func (p *path) Copy() Path {
+	return &path{
+		sciondPath: p.sciondPath.Copy(),
+		spath:      p.spath.Copy(),
+		overlay:    p.overlay.Copy(),
+		source:     p.source,
+	}
+}
+
 // partialPath is a path object with incomplete metadata. It is used as a
 // temporary solution where a full path cannot be reconstituted from other
 // objects, notably snet.Addr.
@@ -215,6 +226,14 @@ func (p *partialPath) MTU() uint16 {
 	return 0
 }
 
+func (p *partialPath) Copy() Path {
+	return &partialPath{
+		spath:       p.spath.Copy(),
+		overlay:     p.overlay.Copy(),
+		destination: p.destination,
+	}
+}
+
 // LocalMachine describes aspects of the host system and its network.
 type LocalMachine struct {
 	// InterfaceIP is the default L3 address for connections originating from

go/lib/svc/resolver.go

@@ -188,3 +188,11 @@ func (p *path) Destination() addr.IA {
 func (p *path) MTU() uint16 {
 	return 0
 }
+
+func (p *path) Copy() snet.Path {
+	return &path{
+		spath:       p.spath.Copy(),
+		overlay:     p.overlay.Copy(),
+		destination: p.destination,
+	}
+}