From e3ef473cd33817a7f9cbc92bc92d3b6594eed225 Mon Sep 17 00:00:00 2001
From: Adam Harrison <harrisonadamw@gmail.com>
Date: Fri, 5 Feb 2016 14:19:55 +0000
Subject: [PATCH] Utility function to disable tx checksum offload

---
 net/ethtool.go | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 net/ethtool.go

diff --git a/net/ethtool.go b/net/ethtool.go
new file mode 100644
index 00000000..34209f0d
--- /dev/null
+++ b/net/ethtool.go
@@ -0,0 +1,52 @@
+package net
+
+import "fmt"
+import "syscall"
+import "unsafe"
+
+const (
+	SIOCETHTOOL     = 0x8946     // linux/sockios.h
+	ETHTOOL_STXCSUM = 0x00000017 // linux/ethtool.h
+	IFNAMSIZ        = 16         // linux/if.h
+)
+
+// linux/if.h 'struct ifreq'
+type IFReqData struct {
+	Name [IFNAMSIZ]byte
+	Data uintptr
+}
+
+// linux/ethtool.h 'struct ethtool_value'
+type EthtoolValue struct {
+	Cmd  uint32
+	Data uint32
+}
+
+// Disable TX checksum offload on specified interface
+func EthtoolTXOff(name string) error {
+	if len(name)+1 > IFNAMSIZ {
+		return fmt.Errorf("name too long")
+	}
+
+	value := EthtoolValue{ETHTOOL_STXCSUM, 0}
+	request := IFReqData{Data: uintptr(unsafe.Pointer(&value))}
+
+	copy(request.Name[:], name)
+
+	socket, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(socket)
+
+	_, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL,
+		uintptr(socket),
+		uintptr(SIOCETHTOOL),
+		uintptr(unsafe.Pointer(&request)))
+
+	if errno != 0 {
+		return errno
+	}
+
+	return nil
+}