Function NewControlMessage

ipv6/control.go:149–169

NewControlMessage returns a new control message. The returned message is large enough for options specified by cf.

(cf ControlFlags)

//
// The returned message is large enough for options specified by cf.
func NewControlMessage(cf ControlFlags) []byte {
	opt := rawOpt{cflags: cf}
	var l int
	if opt.isset(FlagTrafficClass) && ctlOpts[ctlTrafficClass].name > 0 {
		l += socket.ControlMessageSpace(ctlOpts[ctlTrafficClass].length)
	}
	if opt.isset(FlagHopLimit) && ctlOpts[ctlHopLimit].name > 0 {
		l += socket.ControlMessageSpace(ctlOpts[ctlHopLimit].length)
	}
	if opt.isset(flagPacketInfo) && ctlOpts[ctlPacketInfo].name > 0 {
		l += socket.ControlMessageSpace(ctlOpts[ctlPacketInfo].length)
	}
	if opt.isset(FlagPathMTU) && ctlOpts[ctlPathMTU].name > 0 {
		l += socket.ControlMessageSpace(ctlOpts[ctlPathMTU].length)
	}
	var b []byte
	if l > 0 {
		b = make([]byte, l)
	}
	return b
}

// Ancillary data socket options
const (