Harden embedded transport under UDP churn

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;
@@ -3534,52 +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,
@@ -7278,23 +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,
-        latest_release_download_url, load_first_native_identity_with_prompt, parse_dynamic_forward,
-        parse_escape_key, parse_local_forward, parse_remote_forward, parse_ssh_config,
-        post_submit_hold_duration, queue_pending_user_input, raw_contains_host_table,
-        recv_response_until, refresh_live_addr, release_tag_download_url,
-        release_tag_from_effective_url, release_version_from_tag, render_status_clear,
-        render_status_overlay, requested_env, resolved_startup_command, retransmit_stream_opens,
-        rewrite_forward_command, selected_predict_mode, selected_udp_host, server_version_mismatch,
-        should_flush_terminal_input_after_contact, should_hold_during_startup_gate,
-        should_hold_post_submit_input, split_after_command_submit, ssh_destination_host,
-        ssh_username, ssh_with_user, startup_command, status_ssh_target, strip_stale_mouse_reports,
-        toml_bare_key_or_quoted, update_check_requested, update_version_status,
-        upsert_managed_block, valid_forward_host, vscode_safe_alias,
+        is_local_status_target, is_resume_response_for_client, latest_release_download_url,
+        load_first_native_identity_with_prompt, parse_dynamic_forward, parse_escape_key,
+        parse_local_forward, parse_remote_forward, parse_ssh_config, post_submit_hold_duration,
+        queue_pending_user_input, raw_contains_host_table, recv_response_until, refresh_live_addr,
+        release_tag_download_url, release_tag_from_effective_url, release_version_from_tag,
+        render_status_clear, render_status_overlay, requested_env, resolved_startup_command,
+        retransmit_stream_opens, rewrite_forward_command, selected_predict_mode, selected_udp_host,
+        server_version_mismatch, should_flush_terminal_input_after_contact,
+        should_hold_during_startup_gate, should_hold_post_submit_input, split_after_command_submit,
+        ssh_destination_host, ssh_username, ssh_with_user, startup_command, status_ssh_target,
+        strip_stale_mouse_reports, toml_bare_key_or_quoted, update_check_requested,
+        update_version_status, 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;
@@ -8524,18 +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_os_error(libc::EHOSTUNREACH));
-            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::ENETUNREACH)
+            ));
+            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_os_error(10065)); // WSAEHOSTUNREACH
-            assert!(is_transient_udp_os_error(10049)); // WSAEADDRNOTAVAIL
-            assert!(!is_transient_udp_os_error(10022)); // WSAEINVAL
+            assert!(is_transient_udp_send_error(
+                &std::io::Error::from_raw_os_error(10051)
+            )); // WSAENETUNREACH
+            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
         }
     }
 

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;
@@ -1713,52 +1714,6 @@ async fn send_udp(socket: &UdpSocket, packet: &[u8], peer: SocketAddr) -> Result
     }
 }
 
-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
-}
-
 async fn handle_ack(
     state: &Arc<Mutex<ServerState>>,
     peer: SocketAddr,