Revert "feat(server): add enable_datagrams, off by default"

This reverts commit e1dc976.

Stream-based video transfer is really painfully bad in the face of either packet
loss or latency. What we really need is FEC.

mm-server/src/config.rs

@@ -87,7 +87,6 @@ mod parsed {
         pub(super) tls_key: Option<PathBuf>,
         pub(super) worker_threads: Option<NonZeroU32>,
         pub(super) max_connections: Option<MaxConnections>,
-        pub(super) enable_datagrams: Option<bool>,
     }
 
     #[derive(Debug, Clone, PartialEq, Deserialize, Converge)]
@@ -122,7 +121,6 @@ pub struct ServerConfig {
     pub tls_key: Option<PathBuf>,
     pub worker_threads: NonZeroU32,
     pub max_connections: Option<NonZeroU32>,
-    pub enable_datagrams: bool,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -184,7 +182,6 @@ impl Config {
                     parsed::MaxConnections::Value(n) => Some(n),
                     parsed::MaxConnections::Infinity => None,
                 },
-                enable_datagrams: server.enable_datagrams.unwrap(),
             },
             apps: HashMap::new(), // Handled below.
             bug_report_dir: None, // This is only set from the command line.

mm-server/src/server/handlers.rs

@@ -259,8 +259,6 @@ fn attach(
         }
     };
 
-    let use_datagrams = state.lock().unwrap().cfg.server.enable_datagrams;
-
     let (handle, display_params, bug_report_dir) = {
         let mut state = state.lock().unwrap();
 
@@ -363,7 +361,6 @@ fn attach(
     // Five varints at max 5 bytes, plus a header, works out to around 32
     // bytes. Double for safety.
     let dgram_chunk_size = max_dgram_len - 64;
-    let stream_chunk_size = protocol::MAX_MESSAGE_SIZE - 64;
 
     loop {
         select! {
@@ -545,13 +542,7 @@ fn attach(
 
                         // TODO FEC
 
-                        let chunk_size = if use_datagrams {
-                            dgram_chunk_size
-                        } else {
-                            stream_chunk_size
-                        };
-
-                        for (chunk, num_chunks, data) in iter_chunks(frame, chunk_size) {
+                        for (chunk, num_chunks, data) in iter_chunks(frame, dgram_chunk_size) {
                             let msg = protocol::VideoChunk {
                                 session_id,
                                 attachment_id: handle.attachment_id,
@@ -564,11 +555,7 @@ fn attach(
                                 timestamp: ts,
                             };
 
-                            if use_datagrams {
-                                outgoing_dgrams.send(msg.into()).ok();
-                            } else {
-                                outgoing.send(msg.into()).ok();
-                            }
+                            outgoing_dgrams.send(msg.into()).ok();
                         }
                     }
                     Ok(CompositorEvent::AudioFrame{ stream_seq, seq, ts, frame }) => {
@@ -580,13 +567,7 @@ fn attach(
                             last_audio_frame_recv = time::Instant::now();
 
 
-                            let chunk_size = if use_datagrams {
-                                dgram_chunk_size
-                            } else {
-                                stream_chunk_size
-                            };
-
-                            for (chunk, num_chunks, data) in iter_chunks(frame, chunk_size) {
+                            for (chunk, num_chunks, data) in iter_chunks(frame, dgram_chunk_size) {
                                 let msg = protocol::AudioChunk {
                                     session_id,
                                     attachment_id: handle.attachment_id,
@@ -599,14 +580,8 @@ fn attach(
                                     timestamp: ts,
                                 };
 
-                                if use_datagrams {
-                                    outgoing_dgrams.send(msg.into()).ok();
-                                } else {
-                                    outgoing.send(msg.into()).ok();
-                                }
+                                outgoing_dgrams.send(msg.into()).ok();
                             }
-
-
                     }
                     Ok(CompositorEvent::CursorUpdate{ image, icon, hotspot_x, hotspot_y }) => {
                         use protocol::update_cursor::CursorIcon;

mmserver.default.toml

@@ -49,14 +49,6 @@ worker_threads = 8
 # to specify no limit.
 max_connections = 4
 
-# Whether to enable the use of QUIC datagrams (RFC 9221) to transmit audio and video
-# packets. Datagrams offer lower latency but decreased robustness in the face of
-# packet loss, so this option can be used to decrease latency if you're on a
-# local network where you know there won't be any loss.
-#
-# This option will likely default to true in a future release.
-enable_datagrams = false
-
 # *** Configured Applications *** 
 #
 # Each application you want to stream must be configured in advance. An example