uapi: insert peer version placeholder

While we don't want people to ever use old protocols, people will
complain if the API "changes", so explicitly make the unset protocol
mean the latest, and add a dummy mechanism of specifying the protocol on
a per-peer basis, which we hope nobody actually ever uses.

diff --git a/uapi.go b/uapi.go
index 1edafe032edaad47bfa65f66b350f29cced03238..1801c4c647a2c449532b7024904f1d44ccbfea4f 100644 (file)
--- a/uapi.go
+++ b/uapi.go
@@ -75,6 +75,7 @@ func ipcGetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 
                        send("public_key=" + peer.handshake.remoteStatic.ToHex())
                        send("preshared_key=" + peer.handshake.presharedKey.ToHex())
+                       send("protocol_version=1")
                        if peer.endpoint != nil {
                                send("endpoint=" + peer.endpoint.DstToString())
                        }
@@ -362,6 +363,13 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
                                ones, _ := network.Mask.Size()
                                device.allowedips.Insert(network.IP, uint(ones), peer)
 
+                       case "protocol_version":
+
+                               if value != "1" {
+                                       logError.Println("Invalid protocol version:", value)
+                                       return &IPCError{Code: ipcErrorInvalid}
+                               }
+
                        default:
                                logError.Println("Invalid UAPI peer key:", key)
                                return &IPCError{Code: ipcErrorInvalid}