Bump release candidate to rc3

Cargo.lock

@@ -436,7 +436,7 @@ dependencies = [
 
 [[package]]
 name = "dosh"
-version = "1.0.0-rc1"
+version = "1.0.0-rc3"
 dependencies = [
  "anyhow",
  "base64",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dosh"
-version = "1.0.0-rc1"
+version = "1.0.0-rc3"
 edition = "2024"
 license = "MIT"
 

scripts/bench-local.sh

@@ -67,6 +67,7 @@ cleanup() {
     kill "$server_pid" 2>/dev/null || true
     wait "$server_pid" 2>/dev/null || true
   fi
+  pkill -f "$server_bin hold --runtime-dir $home/sessions/run" 2>/dev/null || true
   rm -rf "$home"
 }
 trap cleanup EXIT INT TERM
@@ -86,6 +87,7 @@ scrollback = 5000
 auth_ttl_secs = 30
 attach_ticket_ttl_secs = 3600
 allow_attach_tickets = true
+persist_sessions = false
 client_timeout_secs = 60
 retransmit_window = 256
 default_input_mode = "read-write"

src/bin/dosh-client.rs

@@ -36,6 +36,7 @@ use dosh::transport::{
     DoshTransport, SessionEvent, SessionRole, SessionTransportConfig, TransportConfig,
     TransportEvent,
 };
+use dosh::udp::is_transient_udp_send_error;
 use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
 use std::collections::BTreeMap;
@@ -63,6 +64,8 @@ const STREAM_INITIAL_WINDOW: usize = 1024 * 1024;
 const MAX_PENDING_USER_INPUT_BYTES: usize = 1024 * 1024;
 const STARTUP_INPUT_HOLD: Duration = Duration::from_millis(750);
 const POST_SUBMIT_ALL_INPUT_HOLD: Duration = Duration::from_millis(120);
+const STALE_TERMINAL_INPUT_AFTER: Duration = Duration::from_secs(2);
+const POST_RECONNECT_STALE_INPUT_GRACE: Duration = Duration::from_secs(2);
 
 /// Sentinel `target_host` the server uses on a server-initiated `StreamOpen` that
 /// represents an SSH-agent connection (rather than a TCP target). The client
@@ -3532,52 +3535,6 @@ async fn send_terminal_udp(socket: &UdpSocket, packet: &[u8], addr: SocketAddr)
     }
 }
 
-fn is_transient_udp_send_error(err: &std::io::Error) -> bool {
-    matches!(
-        err.kind(),
-        std::io::ErrorKind::Interrupted
-            | std::io::ErrorKind::TimedOut
-            | std::io::ErrorKind::WouldBlock
-    ) || err.raw_os_error().is_some_and(is_transient_udp_os_error)
-}
-
-#[cfg(unix)]
-fn is_transient_udp_os_error(code: i32) -> bool {
-    matches!(
-        code,
-        libc::EADDRNOTAVAIL
-            | libc::ECONNREFUSED
-            | libc::ECONNRESET
-            | libc::EHOSTDOWN
-            | libc::EHOSTUNREACH
-            | libc::ENETDOWN
-            | libc::ENETRESET
-            | libc::ENETUNREACH
-            | libc::ETIMEDOUT
-    )
-}
-
-#[cfg(windows)]
-fn is_transient_udp_os_error(code: i32) -> bool {
-    matches!(
-        code,
-        10049  // WSAEADDRNOTAVAIL
-            | 10050 // WSAENETDOWN
-            | 10051 // WSAENETUNREACH
-            | 10052 // WSAENETRESET
-            | 10054 // WSAECONNRESET
-            | 10060 // WSAETIMEDOUT
-            | 10061 // WSAECONNREFUSED
-            | 10064 // WSAEHOSTDOWN
-            | 10065 // WSAEHOSTUNREACH
-    )
-}
-
-#[cfg(not(any(unix, windows)))]
-fn is_transient_udp_os_error(_code: i32) -> bool {
-    false
-}
-
 #[allow(clippy::too_many_arguments)]
 async fn try_native_auth(
     socket: &UdpSocket,
@@ -4376,6 +4333,7 @@ async fn run_terminal(
     let mut pending_user_input_bytes = 0usize;
     let mut startup_input_hold_until: Option<Instant> = None;
     let mut startup_gate_mode = StartupGateMode::HoldControl;
+    let mut stale_terminal_input_suppress_until: Option<Instant> = None;
     if let Some(frame) = first_frame {
         if !forward_only {
             render_frame(&frame)?;
@@ -4433,10 +4391,19 @@ async fn run_terminal(
             biased;
             stdin_msg = stdin_rx.recv() => {
                 match stdin_msg {
-                    Some(bytes) => {
+                    Some(mut bytes) => {
                         if input_matches_escape(&bytes, escape_key.as_deref()) {
                             break;
                         }
+                        if should_strip_stale_terminal_reports(
+                            last_packet_at.elapsed(),
+                            stale_terminal_input_suppress_until,
+                        ) {
+                            bytes = strip_stale_mouse_reports(&bytes);
+                            if bytes.is_empty() {
+                                continue;
+                            }
+                        }
                         if cred.mode != "view-only" && cred.mode != "forward-only" {
                             if let Some(deadline) = startup_input_hold_until {
                                 if !predictor.alternate_screen
@@ -4535,6 +4502,9 @@ async fn run_terminal(
                                 .await?
                                 {
                                     refresh_live_addr(&mut addr, &cred)?;
+                                    arm_stale_terminal_input_suppression(
+                                        &mut stale_terminal_input_suppress_until,
+                                    );
                                     if !forward_only {
                                         render_frame(&frame)?;
                                         predictor.observe_output(&frame.bytes);
@@ -4594,6 +4564,9 @@ async fn run_terminal(
                     .await?
                 {
                     refresh_live_addr(&mut addr, &cred)?;
+                    arm_stale_terminal_input_suppression(
+                        &mut stale_terminal_input_suppress_until,
+                    );
                     if !forward_only {
                         render_frame(&frame)?;
                         predictor.observe_output(&frame.bytes);
@@ -4644,6 +4617,9 @@ async fn run_terminal(
                             .await?
                             {
                                 refresh_live_addr(&mut addr, &cred)?;
+                                arm_stale_terminal_input_suppression(
+                                    &mut stale_terminal_input_suppress_until,
+                                );
                                 if !forward_only {
                                     render_frame(&frame)?;
                                     predictor.observe_output(&frame.bytes);
@@ -4765,6 +4741,9 @@ async fn run_terminal(
                             .await?
                             {
                                 refresh_live_addr(&mut addr, &cred)?;
+                                arm_stale_terminal_input_suppression(
+                                    &mut stale_terminal_input_suppress_until,
+                                );
                                 if !forward_only {
                                     render_frame(&frame)?;
                                     predictor.observe_output(&frame.bytes);
@@ -5157,6 +5136,9 @@ async fn run_terminal(
                     .await?
                     {
                         refresh_live_addr(&mut addr, &cred)?;
+                        arm_stale_terminal_input_suppression(
+                            &mut stale_terminal_input_suppress_until,
+                        );
                         if !forward_only {
                             render_frame(&frame)?;
                             predictor.observe_output(&frame.bytes);
@@ -5562,6 +5544,18 @@ fn should_flush_terminal_input_after_contact(
     !forward_only && !pending_empty && mode != "view-only" && mode != "forward-only"
 }
 
+fn should_strip_stale_terminal_reports(
+    silent_for: Duration,
+    suppress_until: Option<Instant>,
+) -> bool {
+    silent_for >= STALE_TERMINAL_INPUT_AFTER
+        || suppress_until.is_some_and(|deadline| Instant::now() < deadline)
+}
+
+fn arm_stale_terminal_input_suppression(suppress_until: &mut Option<Instant>) {
+    *suppress_until = Some(Instant::now() + POST_RECONNECT_STALE_INPUT_GRACE);
+}
+
 async fn flush_pending_user_input(
     socket: &UdpSocket,
     addr: SocketAddr,
@@ -5623,6 +5617,7 @@ fn stale_mouse_report_len(bytes: &[u8], offset: usize) -> Option<usize> {
     match bytes.get(offset).copied()? {
         0x1b if bytes.get(offset + 1) == Some(&b'[') => match bytes.get(offset + 2).copied() {
             Some(b'M') if offset + 6 <= bytes.len() => Some(6),
+            Some(b'I' | b'O') => Some(3),
             Some(b'<') => mouse_report_params_len(bytes, offset + 3, 2).map(|len| len + 3),
             Some(byte) if byte.is_ascii_digit() => {
                 mouse_report_params_len(bytes, offset + 2, 2).map(|len| len + 2)
@@ -5631,13 +5626,15 @@ fn stale_mouse_report_len(bytes: &[u8], offset: usize) -> Option<usize> {
         },
         0x9b => match bytes.get(offset + 1).copied() {
             Some(b'M') if offset + 5 <= bytes.len() => Some(5),
+            Some(b'I' | b'O') => Some(2),
             Some(b'<') => mouse_report_params_len(bytes, offset + 2, 2).map(|len| len + 2),
             Some(byte) if byte.is_ascii_digit() => {
                 mouse_report_params_len(bytes, offset + 1, 2).map(|len| len + 1)
             }
             _ => None,
         },
-        byte if byte.is_ascii_digit() => mouse_report_params_len(bytes, offset, 1),
+        byte if byte.is_ascii_digit() => mouse_report_params_len(bytes, offset, 1)
+            .or_else(|| orphan_mouse_suffix_len(bytes, offset)),
         _ => None,
     }
 }
@@ -5659,6 +5656,21 @@ fn mouse_report_params_len(bytes: &[u8], offset: usize, min_semicolons: usize) -
     None
 }
 
+fn orphan_mouse_suffix_len(bytes: &[u8], offset: usize) -> Option<usize> {
+    if offset != 0 {
+        return None;
+    }
+    let mut cursor = offset;
+    while let Some(byte) = bytes.get(cursor).copied() {
+        match byte {
+            b'0'..=b'9' => cursor += 1,
+            b'M' | b'm' if cursor > offset => return Some(cursor + 1 - offset),
+            _ => return None,
+        }
+    }
+    None
+}
+
 fn stale_mouse_report_maybe_incomplete(bytes: &[u8], offset: usize) -> bool {
     let Some(rest) = bytes.get(offset..) else {
         return false;
@@ -7221,23 +7233,23 @@ mod tests {
         PredictMode, Predictor, RESTART_STATUS_SCRIPT, RemoteForward, STARTUP_INPUT_HOLD,
         SshConfig, StartupGateMode, StatusAction, auth_allows, cache_key, cache_server_prefix,
         clear_cached_credentials, ensure_tui_safe_status_overlay, input_matches_escape,
-        is_local_status_target, is_resume_response_for_client, is_transient_udp_os_error,
+        is_local_status_target, is_resume_response_for_client, latest_release_download_url,
-        latest_release_download_url, load_first_native_identity_with_prompt, parse_dynamic_forward,
+        load_first_native_identity_with_prompt, parse_dynamic_forward, parse_escape_key,
-        parse_escape_key, parse_local_forward, parse_remote_forward, parse_ssh_config,
+        parse_local_forward, parse_remote_forward, parse_ssh_config, post_submit_hold_duration,
-        post_submit_hold_duration, queue_pending_user_input, raw_contains_host_table,
+        queue_pending_user_input, raw_contains_host_table, recv_response_until, refresh_live_addr,
-        recv_response_until, refresh_live_addr, release_tag_download_url,
+        release_tag_download_url, release_tag_from_effective_url, release_version_from_tag,
-        release_tag_from_effective_url, release_version_from_tag, render_status_clear,
+        render_status_clear, render_status_overlay, requested_env, resolved_startup_command,
-        render_status_overlay, requested_env, resolved_startup_command, retransmit_stream_opens,
+        retransmit_stream_opens, rewrite_forward_command, selected_predict_mode, selected_udp_host,
-        rewrite_forward_command, selected_predict_mode, selected_udp_host, server_version_mismatch,
+        server_version_mismatch, should_flush_terminal_input_after_contact,
-        should_flush_terminal_input_after_contact, should_hold_during_startup_gate,
+        should_hold_during_startup_gate, should_hold_post_submit_input, split_after_command_submit,
-        should_hold_post_submit_input, split_after_command_submit, ssh_destination_host,
+        ssh_destination_host, ssh_username, ssh_with_user, startup_command, status_ssh_target,
-        ssh_username, ssh_with_user, startup_command, status_ssh_target, strip_stale_mouse_reports,
+        strip_stale_mouse_reports, toml_bare_key_or_quoted, update_check_requested,
-        toml_bare_key_or_quoted, update_check_requested, update_version_status,
+        update_version_status, upsert_managed_block, valid_forward_host, vscode_safe_alias,
-        upsert_managed_block, valid_forward_host, vscode_safe_alias,
     };
     use dosh::config::{ClientConfig, CommandExtension, HostConfig};
     use dosh::native::EnvVar;
     use dosh::protocol::{self, Frame, PacketKind};
+    use dosh::udp::is_transient_udp_send_error;
     use ed25519_dalek::{SigningKey, VerifyingKey};
     use std::collections::{HashMap, VecDeque};
     use std::fs;
@@ -8467,18 +8479,34 @@ mod tests {
     fn transient_udp_send_errors_are_not_terminal_fatal() {
         #[cfg(unix)]
         {
-            assert!(is_transient_udp_os_error(libc::ENETUNREACH));
+            assert!(is_transient_udp_send_error(
-            assert!(is_transient_udp_os_error(libc::EHOSTUNREACH));
+                &std::io::Error::from_raw_os_error(libc::ENETUNREACH)
-            assert!(is_transient_udp_os_error(libc::EADDRNOTAVAIL));
+            ));
-            assert!(!is_transient_udp_os_error(libc::EINVAL));
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(libc::EHOSTUNREACH)
+            ));
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(libc::EADDRNOTAVAIL)
+            ));
+            assert!(!is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(libc::EINVAL)
+            ));
         }
 
         #[cfg(windows)]
         {
-            assert!(is_transient_udp_os_error(10051)); // WSAENETUNREACH
+            assert!(is_transient_udp_send_error(
-            assert!(is_transient_udp_os_error(10065)); // WSAEHOSTUNREACH
+                &std::io::Error::from_raw_os_error(10051)
-            assert!(is_transient_udp_os_error(10049)); // WSAEADDRNOTAVAIL
+            )); // WSAENETUNREACH
-            assert!(!is_transient_udp_os_error(10022)); // WSAEINVAL
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(10065)
+            )); // WSAEHOSTUNREACH
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(10049)
+            )); // WSAEADDRNOTAVAIL
+            assert!(!is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(10022)
+            )); // WSAEINVAL
         }
     }
 
@@ -8495,6 +8523,18 @@ mod tests {
         assert_eq!(strip_stale_mouse_reports(b"152;1Mls\r"), b"ls\r");
     }
 
+    #[test]
+    fn split_stale_mouse_suffixes_are_stripped_from_pending_input() {
+        assert_eq!(strip_stale_mouse_reports(b"1M35;149;1Mls\r"), b"ls\r");
+        assert_eq!(strip_stale_mouse_reports(b"10m"), b"");
+    }
+
+    #[test]
+    fn stale_focus_reports_are_stripped_from_pending_input() {
+        assert_eq!(strip_stale_mouse_reports(b"\x1b[Ihello\x1b[O"), b"hello");
+        assert_eq!(strip_stale_mouse_reports(b"\x9bIhello\x9bO"), b"hello");
+    }
+
     #[test]
     fn non_mouse_escape_input_survives_stale_filter() {
         assert_eq!(strip_stale_mouse_reports(b"\x1b[A"), b"\x1b[A");

src/bin/dosh-server.rs

@@ -28,6 +28,7 @@ use dosh::protocol::{
     TicketAttachBody, TicketAttachEnvelope, TicketAttachOkEnvelope,
 };
 use dosh::pty::{PtyHandle, PtyOutput, adopt_pty_from_fd, spawn_pty_session};
+use dosh::udp::is_transient_udp_send_error;
 use sha2::{Digest, Sha256};
 use std::collections::{BTreeMap, HashMap, HashSet, VecDeque};
 use std::fs;
@@ -980,7 +981,7 @@ async fn handle_native_client_hello(
     };
     let body = protocol::to_body(&NativeServerHelloBody { hello })?;
     let out = protocol::encode_plain(PacketKind::NativeServerHello, pending_id, 1, 0, &body)?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1058,7 +1059,7 @@ async fn handle_native_user_auth(
             SERVER_TO_CLIENT,
             &body,
         )?;
-        socket.send_to(&out, peer).await?;
+        let _ = send_udp(socket, &out, peer).await?;
         return Ok(());
     }
 
@@ -1251,7 +1252,7 @@ async fn handle_native_user_auth(
         SERVER_TO_CLIENT,
         &body,
     )?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1359,7 +1360,7 @@ async fn handle_bootstrap_attach(
         SERVER_TO_CLIENT,
         &body,
     )?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1494,7 +1495,7 @@ async fn handle_ticket_attach(
     };
     let body = protocol::to_body(&envelope)?;
     let out = protocol::encode_plain(PacketKind::AttachOk, client_id, 1, 0, &body)?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1512,7 +1513,7 @@ async fn send_reject_to_client(
         reason: reason.to_string(),
     })?;
     let out = protocol::encode_plain(PacketKind::AttachReject, client_id, 0, 0, &body)?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1578,7 +1579,7 @@ async fn handle_resume(
         SERVER_TO_CLIENT,
         &body,
     )?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1690,7 +1691,7 @@ async fn handle_ping(
         SERVER_TO_CLIENT,
         b"",
     )?;
-    socket.send_to(&out, peer).await?;
+    let _ = send_udp(socket, &out, peer).await?;
     Ok(())
 }
 
@@ -1705,6 +1706,14 @@ fn remove_client(state: &Arc<Mutex<ServerState>>, client_id: [u8; 16]) {
     locked.remove_client_everywhere(&client_id);
 }
 
+async fn send_udp(socket: &UdpSocket, packet: &[u8], peer: SocketAddr) -> Result<bool> {
+    match socket.send_to(packet, peer).await {
+        Ok(_) => Ok(true),
+        Err(err) if is_transient_udp_send_error(&err) => Ok(false),
+        Err(err) => Err(err).with_context(|| format!("send UDP packet to {peer}")),
+    }
+}
+
 async fn handle_ack(
     state: &Arc<Mutex<ServerState>>,
     peer: SocketAddr,
@@ -3020,7 +3029,7 @@ async fn send_stream_open_to_client(
         found
     };
     if let Some((endpoint, packet)) = send {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -3114,7 +3123,7 @@ async fn queue_or_send_stream_data_to_client(
         send
     };
     if let Some((endpoint, packet)) = send {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -3189,7 +3198,7 @@ async fn flush_stream_pending_data_to_client(
         let Some((endpoint, packet)) = send else {
             return Ok(());
         };
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
 }
 
@@ -3333,7 +3342,7 @@ async fn send_stream_packet_to_client(
         found
     };
     if let Some((endpoint, packet)) = send {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -3435,7 +3444,7 @@ async fn broadcast_output(
         }
     }
     for (endpoint, packet) in sends {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -3488,7 +3497,7 @@ async fn broadcast_session_exit(
         persist::remove_runtime_dir(&sessions_dir, &session_name);
     }
     for (endpoint, packet) in sends {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -3595,7 +3604,7 @@ async fn retransmit_pending(
         sends
     };
     for (endpoint, packet) in sends {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -3691,7 +3700,7 @@ async fn maybe_rekey_clients(
         sends
     };
     for (endpoint, packet) in sends {
-        socket.send_to(&packet, endpoint).await?;
+        let _ = send_udp(socket, &packet, endpoint).await?;
     }
     Ok(())
 }
@@ -4536,4 +4545,25 @@ mod tests {
         };
         remote_bind_allowed(&config, "0.0.0.0").unwrap();
     }
+
+    #[cfg(unix)]
+    #[test]
+    fn server_udp_send_classifier_treats_network_roaming_errors_as_transient() {
+        for code in [
+            libc::EADDRNOTAVAIL,
+            libc::ECONNREFUSED,
+            libc::ECONNRESET,
+            libc::EHOSTDOWN,
+            libc::EHOSTUNREACH,
+            libc::ENETDOWN,
+            libc::ENETRESET,
+            libc::ENETUNREACH,
+            libc::ETIMEDOUT,
+        ] {
+            assert!(
+                is_transient_udp_send_error(&std::io::Error::from_raw_os_error(code)),
+                "expected errno {code} to be transient"
+            );
+        }
+    }
 }

src/lib.rs

@@ -23,3 +23,4 @@ pub mod pty;
 pub mod server;
 pub mod ssh_agent;
 pub mod transport;
+pub mod udp;

src/transport.rs

@@ -19,6 +19,7 @@ use crate::protocol::{
     self, CLIENT_TO_SERVER, PacketKind, ReplayWindow, SERVER_TO_CLIENT, StreamClose, StreamData,
     StreamOpen, StreamOpenOk, StreamOpenReject, StreamWindowAdjust,
 };
+use crate::udp::is_transient_udp_send_error;
 use anyhow::{Result, anyhow, bail};
 use std::collections::{BTreeMap, HashMap, HashSet, VecDeque};
 use std::net::SocketAddr;
@@ -348,8 +349,8 @@ impl StreamMux {
         &mut self,
         adjust: StreamWindowAdjust,
     ) -> Result<Vec<OutgoingStreamPacket>> {
-        self.ack_data(adjust.stream_id, adjust.received_offset);
+        let acked_bytes = self.ack_data(adjust.stream_id, adjust.received_offset);
-        self.add_credit(adjust.stream_id, adjust.bytes as usize);
+        self.add_credit(adjust.stream_id, acked_bytes);
         self.flush_pending_data(adjust.stream_id)
     }
 
@@ -556,9 +557,9 @@ impl StreamMux {
         (chunks, consumed, *expected)
     }
 
-    fn ack_data(&mut self, stream_id: u64, received_offset: u64) {
+    fn ack_data(&mut self, stream_id: u64, received_offset: u64) -> usize {
         let Some(sent) = self.sent_data.get_mut(&stream_id) else {
-            return;
+            return 0;
         };
         let acked_offsets = sent
             .iter()
@@ -567,12 +568,16 @@ impl StreamMux {
                 (end <= received_offset).then_some(*offset)
             })
             .collect::<Vec<_>>();
+        let mut acked_bytes = 0usize;
         for offset in acked_offsets {
-            sent.remove(&offset);
+            if let Some(chunk) = sent.remove(&offset) {
+                acked_bytes = acked_bytes.saturating_add(chunk.bytes.len());
+            }
         }
         if sent.is_empty() {
             self.sent_data.remove(&stream_id);
         }
+        acked_bytes
     }
 
     fn add_credit(&mut self, stream_id: u64, bytes: usize) {
@@ -815,7 +820,12 @@ impl DoshTransport {
 
     async fn send_kind(&mut self, kind: PacketKind, body: &[u8]) -> Result<()> {
         let encoded = self.encode_kind(kind, body)?;
-        self.socket.send_to(&encoded, self.peer_addr).await?;
+        if let Err(err) = self.socket.send_to(&encoded, self.peer_addr).await {
+            if is_transient_udp_send_error(&err) {
+                return Ok(());
+            }
+            return Err(err.into());
+        }
         Ok(())
     }
 
@@ -980,6 +990,30 @@ mod tests {
         assert_eq!(data.bytes, b"!");
     }
 
+    #[test]
+    fn cumulative_window_adjust_restores_credit_even_if_delta_was_lost() {
+        let mut mux = StreamMux::new(TransportConfig {
+            initial_window: 5,
+            retransmit_after: Duration::from_secs(1),
+            ..TransportConfig::default()
+        });
+        mux.open_stream(1, "@dosh-test", 0).unwrap();
+        mux.handle_open_ok(StreamOpenOk { stream_id: 1 }).unwrap();
+        assert_eq!(mux.send_data(1, b"hello".to_vec()).unwrap().len(), 1);
+        assert_eq!(mux.send_credit[&1], 0);
+
+        let flushed = mux
+            .handle_window_adjust(StreamWindowAdjust {
+                stream_id: 1,
+                received_offset: 5,
+                bytes: 0,
+            })
+            .unwrap();
+        assert!(flushed.is_empty());
+        assert_eq!(mux.send_credit[&1], 5);
+        assert_eq!(mux.send_data(1, b"!".to_vec()).unwrap().len(), 1);
+    }
+
     #[test]
     fn handle_packet_decodes_and_dispatches_stream_packets() {
         let mut mux = StreamMux::new(TransportConfig::default());

src/udp.rs

@@ -0,0 +1,98 @@
+//! UDP error classification shared by Dosh clients, servers, and embedders.
+
+pub fn is_transient_udp_send_error(err: &std::io::Error) -> bool {
+    matches!(
+        err.kind(),
+        std::io::ErrorKind::Interrupted
+            | std::io::ErrorKind::TimedOut
+            | std::io::ErrorKind::WouldBlock
+    ) || err.raw_os_error().is_some_and(is_transient_udp_os_error)
+}
+
+#[cfg(unix)]
+fn is_transient_udp_os_error(code: i32) -> bool {
+    matches!(
+        code,
+        libc::EADDRNOTAVAIL
+            | libc::ECONNREFUSED
+            | libc::ECONNRESET
+            | libc::EHOSTDOWN
+            | libc::EHOSTUNREACH
+            | libc::ENETDOWN
+            | libc::ENETRESET
+            | libc::ENETUNREACH
+            | libc::ETIMEDOUT
+    )
+}
+
+#[cfg(windows)]
+fn is_transient_udp_os_error(code: i32) -> bool {
+    matches!(
+        code,
+        10049  // WSAEADDRNOTAVAIL
+            | 10050 // WSAENETDOWN
+            | 10051 // WSAENETUNREACH
+            | 10052 // WSAENETRESET
+            | 10054 // WSAECONNRESET
+            | 10060 // WSAETIMEDOUT
+            | 10061 // WSAECONNREFUSED
+            | 10064 // WSAEHOSTDOWN
+            | 10065 // WSAEHOSTUNREACH
+    )
+}
+
+#[cfg(not(any(unix, windows)))]
+fn is_transient_udp_os_error(_code: i32) -> bool {
+    false
+}
+
+#[cfg(test)]
+mod tests {
+    use super::is_transient_udp_send_error;
+
+    #[test]
+    fn classifies_portable_transient_send_errors() {
+        for kind in [
+            std::io::ErrorKind::Interrupted,
+            std::io::ErrorKind::TimedOut,
+            std::io::ErrorKind::WouldBlock,
+        ] {
+            assert!(is_transient_udp_send_error(&std::io::Error::from(kind)));
+        }
+        assert!(!is_transient_udp_send_error(&std::io::Error::from(
+            std::io::ErrorKind::PermissionDenied,
+        )));
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn classifies_unix_network_churn_as_transient() {
+        for code in [
+            libc::EADDRNOTAVAIL,
+            libc::ECONNREFUSED,
+            libc::ECONNRESET,
+            libc::EHOSTDOWN,
+            libc::EHOSTUNREACH,
+            libc::ENETDOWN,
+            libc::ENETRESET,
+            libc::ENETUNREACH,
+            libc::ETIMEDOUT,
+        ] {
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(code)
+            ));
+        }
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn classifies_windows_network_churn_as_transient() {
+        for code in [
+            10049, 10050, 10051, 10052, 10054, 10060, 10061, 10064, 10065,
+        ] {
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(code)
+            ));
+        }
+    }
+}