ipv4: remove unnecessary control message marshaling

The encoded data is just for debugging at kernel side and has remained
in normal code path until now, oops.

Change-Id: I28003ae211eb63d717d7e20f39ee0f39201892a5
Reviewed-on: https://go-review.googlesource.com/31534
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

ipv4/control_unix.go

@@ -83,22 +83,6 @@ func newControlMessage(opt *rawOpt) (oob []byte) {
 	}
 	if l > 0 {
 		oob = make([]byte, l)
-		b := oob
-		if opt.isset(FlagTTL) && ctlOpts[ctlTTL].name > 0 {
-			b = ctlOpts[ctlTTL].marshal(b, nil)
-		}
-		if ctlOpts[ctlPacketInfo].name > 0 {
-			if opt.isset(FlagSrc | FlagDst | FlagInterface) {
-				b = ctlOpts[ctlPacketInfo].marshal(b, nil)
-			}
-		} else {
-			if opt.isset(FlagDst) && ctlOpts[ctlDst].name > 0 {
-				b = ctlOpts[ctlDst].marshal(b, nil)
-			}
-			if opt.isset(FlagInterface) && ctlOpts[ctlInterface].name > 0 {
-				b = ctlOpts[ctlInterface].marshal(b, nil)
-			}
-		}
 	}
 	opt.RUnlock()
 	return