1 files changed, 16 insertions, 5 deletions
diff --git a/libgo/go/net/tcpsockopt_windows.go b/libgo/go/net/tcpsockopt_windows.go
index 0bf4312f24..091f5233f2 100644
--- a/libgo/go/net/tcpsockopt_windows.go
+++ b/libgo/go/net/tcpsockopt_windows.go
@@ -2,12 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// TCP socket options for windows
-
 package net
 
 import (
+	"os"
+	"syscall"
 	"time"
+	"unsafe"
 )
 
 func setKeepAlivePeriod(fd *netFD, d time.Duration) error {
@@ -15,7 +16,17 @@ func setKeepAlivePeriod(fd *netFD, d time.Duration) error {
 		return err
 	}
 	defer fd.decref()
-
-	// We can't actually set this per connection.  Act as a noop rather than an error.
-	return nil
+	// The kernel expects milliseconds so round to next highest
+	// millisecond.
+	d += (time.Millisecond - time.Nanosecond)
+	msecs := uint32(d / time.Millisecond)
+	ka := syscall.TCPKeepalive{
+		OnOff:    1,
+		Time:     msecs,
+		Interval: msecs,
+	}
+	ret := uint32(0)
+	size := uint32(unsafe.Sizeof(ka))
+	err := syscall.WSAIoctl(fd.sysfd, syscall.SIO_KEEPALIVE_VALS, (*byte)(unsafe.Pointer(&ka)), size, nil, 0, &ret, nil, 0)
+	return os.NewSyscallError("WSAIoctl", err)
 }