Merge pull request #459 from dolonet/fix/openbsd-keepalive

Fix TCP keepalive setup on OpenBSD

network/sockopts.go

 }
 
 func setCommonSocketOptions(conn *net.TCPConn) error {
-	if err := conn.SetKeepAliveConfig(net.KeepAliveConfig{
+	if err := applyKeepAlive(conn, net.KeepAliveConfig{
 		Enable:   true,
 		Idle:     DefaultKeepAliveIdle,
 		Interval: DefaultKeepAliveInterval,

network/sockopts_keepalive.go

+//go:build !openbsd
+
+package network
+
+import "net"
+
+// applyKeepAlive enables TCP keepalive on conn and applies the per-socket
+// idle/interval/count tuning from cfg.
+func applyKeepAlive(conn *net.TCPConn, cfg net.KeepAliveConfig) error {
+	return conn.SetKeepAliveConfig(cfg) //nolint: wrapcheck
+}

network/sockopts_keepalive_openbsd.go

+package network
+
+import "net"
+
+// applyKeepAlive enables (or disables) TCP keepalive on conn.
+//
+// OpenBSD has no user-settable per-socket TCP keepalive options: TCP_KEEPIDLE,
+// TCP_KEEPINTVL and TCP_KEEPCNT do not exist on OpenBSD, and Go's
+// (*TCPConn).SetKeepAliveConfig therefore returns ENOPROTOOPT ("protocol not
+// available") for any non-negative Idle/Interval/Count value (see
+// src/net/tcpsockopt_openbsd.go in the Go source tree). Calling
+// SetKeepAliveConfig with mtg's defaults (zero values) breaks every accepted
+// listener connection and every outbound dial on OpenBSD.
+//
+// On OpenBSD we only flip SO_KEEPALIVE on or off; the keepalive timing is
+// controlled system-wide via the sysctl knobs net.inet.tcp.keepidle and
+// net.inet.tcp.keepintvl.
+func applyKeepAlive(conn *net.TCPConn, cfg net.KeepAliveConfig) error {
+	return conn.SetKeepAlive(cfg.Enable) //nolint: wrapcheck
+}

network/v2/sockopts.go

 )
 
 func setCommonSocketOptions(conn *net.TCPConn, keepAliveConfig net.KeepAliveConfig) error {
-	if err := conn.SetKeepAliveConfig(keepAliveConfig); err != nil {
+	if err := applyKeepAlive(conn, keepAliveConfig); err != nil {
 		return fmt.Errorf("cannot configure TCP keepalive: %w", err)
 	}
 

network/v2/sockopts_keepalive.go

+//go:build !openbsd
+
+package network
+
+import "net"
+
+// applyKeepAlive enables TCP keepalive on conn and applies the per-socket
+// idle/interval/count tuning from cfg.
+func applyKeepAlive(conn *net.TCPConn, cfg net.KeepAliveConfig) error {
+	return conn.SetKeepAliveConfig(cfg) //nolint: wrapcheck
+}

network/v2/sockopts_keepalive_openbsd.go

+package network
+
+import "net"
+
+// applyKeepAlive enables (or disables) TCP keepalive on conn.
+//
+// OpenBSD has no user-settable per-socket TCP keepalive options: TCP_KEEPIDLE,
+// TCP_KEEPINTVL and TCP_KEEPCNT do not exist on OpenBSD, and Go's
+// (*TCPConn).SetKeepAliveConfig therefore returns ENOPROTOOPT ("protocol not
+// available") for any non-negative Idle/Interval/Count value (see
+// src/net/tcpsockopt_openbsd.go in the Go source tree). Calling
+// SetKeepAliveConfig with mtg's defaults (zero values) breaks every accepted
+// listener connection and every outbound dial on OpenBSD.
+//
+// On OpenBSD we only flip SO_KEEPALIVE on or off; the keepalive timing is
+// controlled system-wide via the sysctl knobs net.inet.tcp.keepidle and
+// net.inet.tcp.keepintvl.
+func applyKeepAlive(conn *net.TCPConn, cfg net.KeepAliveConfig) error {
+	return conn.SetKeepAlive(cfg.Enable) //nolint: wrapcheck
+}