tcp,udp: idle timeout as sockopt where possible

intra/common.go

@@ -235,6 +235,8 @@ func (h *baseHandler) forward(local, remote net.Conn, smm *SocketSummary) {
 	if r, ok := remote.(rwext); ok {
 		if r.IsZeroDeadline() {
 			remote = r.Unwrap()
+		} else if c, ok := r.SetAsTCPSockOpt(); ok {
+			remote = c
 		}
 	}
 

intra/core/sockopt.go

@@ -40,6 +40,31 @@ func SetKeepAliveConfig(c MinConn) bool {
 	return false
 }
 
+func SetTimeoutSockOpt(c MinConn, timeoutms int) bool {
+	if tc, ok := c.(*net.TCPConn); ok {
+		id := conn2str(tc)
+		rawConn, err := tc.SyscallConn()
+		if err != nil || rawConn == nil {
+			return false
+		}
+		ok := true
+		err = rawConn.Control(func(fd uintptr) {
+			sock := int(fd)
+			// code.googlesource.com/google-api-go-client/+/master/transport/grpc/dial_socketopt.go#30
+			if err := unix.SetsockoptInt(sock, unix.SOL_TCP, unix.TCP_USER_TIMEOUT, timeoutms); err != nil {
+				log.D("core: sockopt: set TCP_USER_TIMEOUT %s (%d) failed: %dms, %v", id, sock, timeoutms, err)
+				ok = false
+			}
+		})
+		if err != nil {
+			log.E("core: sockopt: %s RawConn.Control() err: %v", id, err)
+			ok = false
+		}
+		return ok
+	}
+	return false
+}
+
 // SetKeepAliveConfigSockOpt sets for a TCP connection, SO_KEEPALIVE,
 // TCP_KEEPIDLE, TCP_KEEPINTVL, TCP_KEEPCNT, TCP_USER_TIMEOUT.
 // args is optional, and should be in the order of idle, interval, count.
@@ -72,29 +97,29 @@ func SetKeepAliveConfigSockOpt(c MinConn, args ...int) (ok bool) {
 		err = rawConn.Control(func(fd uintptr) {
 			sock := int(fd)
 			if err := syscall.SetsockoptInt(sock, syscall.SOL_SOCKET, syscall.SO_KEEPALIVE, boolint(true)); err != nil {
-				log.D("set SO_KEEPALIVE %s failed: %v", id, err)
+				log.D("core: sockopt: set SO_KEEPALIVE %s (%d) failed: %v", id, sock, err)
 				ok = false
 			}
 			if err := syscall.SetsockoptInt(sock, syscall.IPPROTO_TCP, syscall.TCP_KEEPIDLE, idle); err != nil {
-				log.D("set TCP_KEEPIDLE %s failed: %ds, %v", id, idle, err)
+				log.D("core: sockopt: set TCP_KEEPIDLE %s (%d) failed: %ds, %v", id, sock, idle, err)
 				ok = false
 			}
 			if err := syscall.SetsockoptInt(sock, syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, interval); err != nil {
-				log.D("set TCP_KEEPINTVL %s failed: %ds, %v", id, interval, err)
+				log.D("core: sockopt: set TCP_KEEPINTVL %s (%d) failed: %ds, %v", id, sock, interval, err)
 				ok = false
 			}
 			if err := syscall.SetsockoptInt(sock, syscall.IPPROTO_TCP, syscall.TCP_KEEPCNT, count); err != nil {
-				log.D("set TCP_KEEPCNT %s failed: #%d, %v", id, count, err)
+				log.D("core: sockopt: set TCP_KEEPCNT %s (%d) failed: #%d, %v", id, sock, count, err)
 				ok = false
 			}
 			// code.googlesource.com/google-api-go-client/+/master/transport/grpc/dial_socketopt.go#30
 			if err := unix.SetsockoptInt(sock, unix.SOL_TCP, unix.TCP_USER_TIMEOUT, usertimeoutms); err != nil {
-				log.D("set TCP_USER_TIMEOUT %s failed: %dms, %v", id, usertimeoutms, err)
+				log.D("core: sockopt: set TCP_USER_TIMEOUT %s (%d) failed: %dms, %v", id, sock, usertimeoutms, err)
 				ok = false
 			}
 		})
 		if err != nil {
-			log.E("dialers: sockopt: %s RawConn.Control() err: %v", id, err)
+			log.E("core: sockopt: %s RawConn.Control() err: %v", id, err)
 			ok = false
 		}
 	}

intra/udp.go

@@ -74,14 +74,24 @@ var _ netstack.GUDPConnHandler = (*udpHandler)(nil)
 // on every read and write.
 type rwext struct {
 	net.Conn        // underlying conn
-	min      uint32 // min idle timeout in secs
+	minidle  uint32 // min idle timeout in secs
 }
 
 func (rw rwext) IsZeroDeadline() bool {
 	r, w := rw.deadlines()
 	return r == 0 && w == 0
 }
 
+func (rw rwext) SetAsTCPSockOpt() (core.TCPConn, bool) {
+	r, _ := rw.deadlines()
+	c, ok := rw.Conn.(core.TCPConn) // no-op for tcp conns
+	if ok && r > 0 {
+		// always returns false for udp conns
+		ok = core.SetTimeoutSockOpt(c, int(r)*1000)
+	}
+	return c, ok
+}
+
 func (rw rwext) Unwrap() net.Conn {
 	return rw.Conn
 }
@@ -99,8 +109,8 @@ func (rw rwext) Write(b []byte) (n int, err error) {
 func (rw rwext) deadlines() (r, w uint32) {
 	dopt := settings.GetDialerOpts()
 	// -ve ints go higher than 2^31 w/ uint: go.dev/play/p/Rrqk_V8a7W0
-	return max(rw.min, uint32(dopt.ReadTimeoutSec)),
-		max(rw.min, uint32(dopt.WriteTimeoutSec))
+	return max(rw.minidle, uint32(dopt.ReadTimeoutSec)),
+		max(rw.minidle, uint32(dopt.WriteTimeoutSec))
 }
 
 func (rw rwext) extend() {