types/key: add MachinePrivate and MachinePublic.

Plumb throughout the codebase as a replacement for the mixed use of
tailcfg.MachineKey and wgkey.Private/Public.

Signed-off-by: David Anderson <danderson@tailscale.com>

tailcfg/tailcfg.go

@@ -77,9 +77,6 @@ func (u StableNodeID) IsZero() bool {
 	return u == ""
 }
 
-// MachineKey is the curve25519 public key for a machine.
-type MachineKey [32]byte
-
 // NodeKey is the curve25519 public key for a node.
 type NodeKey [32]byte
 
@@ -157,7 +154,7 @@ type Node struct {
 
 	Key        NodeKey
 	KeyExpiry  time.Time
-	Machine    MachineKey
+	Machine    key.MachinePublic
 	DiscoKey   DiscoKey
 	Addresses  []netaddr.IPPrefix // IP addresses of this Node directly
 	AllowedIPs []netaddr.IPPrefix // range of IP addresses to route to this node
@@ -1078,11 +1075,6 @@ type Debug struct {
 	DisableUPnP opt.Bool `json:",omitempty"`
 }
 
-func (k MachineKey) String() string                   { return fmt.Sprintf("mkey:%x", k[:]) }
-func (k MachineKey) MarshalText() ([]byte, error)     { return keyMarshalText("mkey:", k), nil }
-func (k MachineKey) HexString() string                { return fmt.Sprintf("%x", k[:]) }
-func (k *MachineKey) UnmarshalText(text []byte) error { return keyUnmarshalText(k[:], "mkey:", text) }
-
 func appendKey(base []byte, prefix string, k [32]byte) []byte {
 	ret := append(base, make([]byte, len(prefix)+64)...)
 	buf := ret[len(base):]
@@ -1116,9 +1108,6 @@ func (k *NodeKey) UnmarshalText(text []byte) error { return keyUnmarshalText(k[:
 // IsZero reports whether k is the zero value.
 func (k NodeKey) IsZero() bool { return k == NodeKey{} }
 
-// IsZero reports whether k is the zero value.
-func (k MachineKey) IsZero() bool { return k == MachineKey{} }
-
 func (k DiscoKey) String() string                   { return fmt.Sprintf("discokey:%x", k[:]) }
 func (k DiscoKey) MarshalText() ([]byte, error)     { return keyMarshalText("discokey:", k), nil }
 func (k *DiscoKey) UnmarshalText(text []byte) error { return keyUnmarshalText(k[:], "discokey:", text) }

tailcfg/tailcfg_clone.go

@@ -9,6 +9,7 @@ package tailcfg
 import (
 	"inet.af/netaddr"
 	"tailscale.com/types/dnstype"
+	"tailscale.com/types/key"
 	"tailscale.com/types/opt"
 	"tailscale.com/types/structs"
 	"time"
@@ -73,7 +74,7 @@ var _NodeNeedsRegeneration = Node(struct {
 	Sharer                  UserID
 	Key                     NodeKey
 	KeyExpiry               time.Time
-	Machine                 MachineKey
+	Machine                 key.MachinePublic
 	DiscoKey                DiscoKey
 	Addresses               []netaddr.IPPrefix
 	AllowedIPs              []netaddr.IPPrefix

tailcfg/tailcfg_test.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"inet.af/netaddr"
+	"tailscale.com/types/key"
 	"tailscale.com/types/wgkey"
 	"tailscale.com/version"
 )
@@ -213,6 +214,7 @@ func TestNodeEqual(t *testing.T) {
 		return k.Public()
 	}
 	n1 := newPublicKey(t)
+	m1 := key.NewMachine().Public()
 	now := time.Now()
 
 	tests := []struct {
@@ -290,13 +292,13 @@ func TestNodeEqual(t *testing.T) {
 			true,
 		},
 		{
-			&Node{Machine: MachineKey(n1)},
-			&Node{Machine: MachineKey(newPublicKey(t))},
+			&Node{Machine: m1},
+			&Node{Machine: key.NewMachine().Public()},
 			false,
 		},
 		{
-			&Node{Machine: MachineKey(n1)},
-			&Node{Machine: MachineKey(n1)},
+			&Node{Machine: m1},
+			&Node{Machine: m1},
 			true,
 		},
 		{
@@ -393,14 +395,6 @@ func TestNetInfoFields(t *testing.T) {
 	}
 }
 
-func TestMachineKeyMarshal(t *testing.T) {
-	var k1, k2 MachineKey
-	for i := range k1 {
-		k1[i] = byte(i)
-	}
-	testKey(t, "mkey:", k1, &k2)
-}
-
 func TestNodeKeyMarshal(t *testing.T) {
 	var k1, k2 NodeKey
 	for i := range k1 {