finish structifying lease, add a stub file for lease2

lib/common/lease.go

@@ -37,13 +37,19 @@ const (
 	LEASE_TUNNEL_DATE_SIZE = 8
 )
 
-type Lease struct {
-	LeaseHash   [LEASE_HASH_SIZE]byte
-	TunnelIdent [LEASE_TUNNEL_ID_SIZE]byte
-	TunnelDate  [LEASE_TUNNEL_DATE_SIZE]byte
+type LeaseInterface interface {
+	TunnelGateway() (hash Hash)
+	TunnelID() uint32
+	Date() (date Date)
 }
 
-//[LEASE_SIZE]byte
+type Lease struct {
+	LeaseHash   Hash //[LEASE_HASH_SIZE]byte
+	TunnelIdent int  //[LEASE_TUNNEL_ID_SIZE]byte
+	TunnelDate  Date //[LEASE_TUNNEL_DATE_SIZE]byte
+} //[LEASE_SIZE]byte
+
+var li LeaseInterface = &Lease{}
 
 //
 // Return the first 32 bytes of the Lease as a Hash.
@@ -54,10 +60,10 @@ func (lease Lease) TunnelGateway() (hash Hash) {
 }
 
 //
-// Parse the TunnelID Integer in the Lease.
+// Return the TunnelID Integer in the Lease.
 //
 func (lease Lease) TunnelID() uint32 {
-	return uint32(Integer(lease.TunnelIdent[:]))
+	return uint32(lease.TunnelIdent)
 }
 
 //
@@ -74,7 +80,7 @@ func (lease Lease) Date() (date Date) {
 func (lease Lease) Bytes() (bytes []byte) {
 	var r []byte
 	r = append(r, lease.LeaseHash[:]...)
-	r = append(r, lease.TunnelIdent[:]...)
+	r = append(r, IntegerBytes(lease.TunnelIdent)[:]...)
 	r = append(r, lease.TunnelDate[:]...)
 	return r
 }

lib/common/lease2.go

@@ -0,0 +1,40 @@
+package common
+
+/*
+Lease2
+https://geti2p.net/spec/common-structures#lease2
+Description
+
+Defines the authorization for a particular tunnel to receive messages targeting a Destination. Same as Lease but with a 4-byte end_date. Used by LeaseSet2. Supported as of 0.9.38; see proposal 123 for more information.
+Contents
+
+SHA256 Hash of the RouterIdentity of the gateway router, then the TunnelId, and finally a 4 byte end date.
+
++----+----+----+----+----+----+----+----+
+| tunnel_gw                             |
++                                       +
+|                                       |
++                                       +
+|                                       |
++                                       +
+|                                       |
++----+----+----+----+----+----+----+----+
+|     tunnel_id     |      end_date     |
++----+----+----+----+----+----+----+----+
+
+tunnel_gw :: Hash of the RouterIdentity of the tunnel gateway
+             length -> 32 bytes
+
+tunnel_id :: TunnelId
+             length -> 4 bytes
+
+end_date :: 4 byte date
+            length -> 4 bytes
+            Seconds since the epoch, rolls over in 2106.
+
+Notes
+
+    Total size: 40 bytes
+
+JavaDoc: http://echelon.i2p/javadoc/net/i2p/data/Lease2.html
+*/