Implement version tag for application as well

1 files changed, 17 insertions, 2 deletions

diff --git a/src/client.rs b/src/client.rs
index e84c85e..27cd1b8 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -52,6 +52,7 @@ impl ClientConn {
 		let remote_addr = socket.peer_addr()?;
 		let mut socket = socket.compat();
 
+		// Do handshake to authenticate and prove our identity to server
 		let handshake = handshake_client(
 			&mut socket,
 			netapp.netid.clone(),
@@ -67,11 +68,25 @@ impl ClientConn {
 			remote_addr
 		);
 
+		// Create BoxStream layer that encodes content
 		let (read, write) = socket.split();
-
-		let (read, write) =
+		let (mut read, write) =
 			BoxStream::from_handshake(read, write, handshake, 0x8000).split_read_write();
 
+		// Before doing anything, receive version tag and
+		// check they are running the same version as us
+		let mut their_version_tag = VersionTag::default();
+		read.read_exact(&mut their_version_tag[..]).await?;
+		if their_version_tag != netapp.version_tag {
+			let msg = format!(
+				"Different netapp versions: {:?} (theirs) vs. {:?} (ours)",
+				their_version_tag, netapp.version_tag
+			);
+			error!("{}", msg);
+			return Err(Error::VersionMismatch(msg));
+		}
+
+		// Build and launch stuff that manages sending requests client-side
 		let (query_send, query_recv) = mpsc::unbounded_channel();
 
 		let (stop_recv_loop, stop_recv_loop_recv) = watch::channel(false);