Implement version tag for application as well

1 files changed, 16 insertions, 1 deletions

diff --git a/src/netapp.rs b/src/netapp.rs
index acaed62..1ac5f37 100644
--- a/src/netapp.rs
+++ b/src/netapp.rs
@@ -24,6 +24,14 @@ use crate::proto::*;
 use crate::server::*;
 use crate::util::*;
 
+/// Tag which is exchanged between client and server upon connection establishment
+/// to check that they are running compatible versions of Netapp,
+/// composed of 8 bytes for Netapp version and 8 bytes for client version
+pub(crate) type VersionTag = [u8; 16];
+
+/// Value of the Netapp version used in the version tag
+pub(crate) const NETAPP_VERSION_TAG: u64 = 0x6e65746170700004; // netapp 0x0004
+
 #[derive(Serialize, Deserialize, Debug)]
 pub(crate) struct HelloMessage {
 	pub server_addr: Option<IpAddr>,
@@ -48,6 +56,8 @@ type OnDisconnectHandler = Box<dyn Fn(NodeID, bool) + Send + Sync>;
 pub struct NetApp {
 	listen_params: ArcSwapOption<ListenParams>,
 
+	/// Version tag, 8 bytes for netapp version, 8 bytes for app version
+	pub version_tag: VersionTag,
 	/// Network secret key
 	pub netid: auth::Key,
 	/// Our peer ID
@@ -76,10 +86,15 @@ impl NetApp {
 	/// using `.listen()`
 	///
 	/// Our Peer ID is the public key associated to the secret key given here.
-	pub fn new(netid: auth::Key, privkey: ed25519::SecretKey) -> Arc<Self> {
+	pub fn new(app_version_tag: u64, netid: auth::Key, privkey: ed25519::SecretKey) -> Arc<Self> {
+		let mut version_tag = [0u8; 16];
+		version_tag[0..8].copy_from_slice(&u64::to_be_bytes(NETAPP_VERSION_TAG)[..]);
+		version_tag[8..16].copy_from_slice(&u64::to_be_bytes(app_version_tag)[..]);
+
 		let id = privkey.public_key();
 		let netapp = Arc::new(Self {
 			listen_params: ArcSwapOption::new(None),
+			version_tag,
 			netid,
 			id,
 			privkey,