---
title: getVlanTagDemand
framework: kernel
role: pseudoSymbol
path: kernel/ioethernetcontroller/1811320-getvlantagdemand
---

# getVlanTagDemand

Fetch the demand for hardware vlan tag stuffing for the given packet before it is transmitted on the network.

## Declaration

```occ
virtual bool getVlanTagDemand(
 mbuf_tm,
 UInt32 *vlanTag); 
```

## Parameters

- `m`: A mbuf containing a packet that may require vlan tag stuffing.
- `vlanTag`: After calling, the low order 16 bits contain the 802.1Q priority and vlan ID tag in host order. The hi-order 16 bits are currently unused and should be ignored.

## Return Value

Return Value true if vlanTag has been set and should be used. false if no vlan tag stuffing is required for this packet.

## Overview

Overview A network controller that can insert 802.1Q vlan tags for output packets must call this method to obtain vlan tag information that it must insert into the given output packet.

## See Also

### Miscellaneous

- [createInterface](kernel/ioethernetcontroller/1811019-createinterface.md)
- [disablePacketFilter](kernel/ioethernetcontroller/1811029-disablepacketfilter.md)
- [enablePacketFilter](kernel/ioethernetcontroller/1811042-enablepacketfilter.md)
- [free](kernel/ioethernetcontroller/1811058-free.md)
- [getHardwareAddress(IOEthernetAddress *)](kernel/ioethernetcontroller/1811070-gethardwareaddress.md)
- [getHardwareAddress(void *, UInt32 *)](kernel/ioethernetcontroller/1811082-gethardwareaddress.md)
- [getMaxPacketSize](kernel/ioethernetcontroller/1811094-getmaxpacketsize.md)
- [getMinPacketSize](kernel/ioethernetcontroller/1811103-getminpacketsize.md)
- [getPacketFilters(const OSSymbol *, UInt32 *)](kernel/ioethernetcontroller/1811115-getpacketfilters.md)
- [getPacketFilters(UInt32 *)](kernel/ioethernetcontroller/1811127-getpacketfilters.md)
- [init](kernel/ioethernetcontroller/1811348-init.md)
- [initialize](kernel/ioethernetcontroller/1811361-initialize.md)
- [publishProperties](kernel/ioethernetcontroller/1811373-publishproperties.md)
- [setHardwareAddress(const IOEthernetAddress *)](kernel/ioethernetcontroller/1811383-sethardwareaddress.md)
- [setHardwareAddress(const void *, UInt32)](kernel/ioethernetcontroller/1811391-sethardwareaddress.md)
- [setMulticastList](kernel/ioethernetcontroller/1811399-setmulticastlist.md)
- [setMulticastMode](kernel/ioethernetcontroller/1811409-setmulticastmode.md)
- [setPromiscuousMode](kernel/ioethernetcontroller/1811419-setpromiscuousmode.md)
- [setVlanTag](kernel/ioethernetcontroller/1811426-setvlantag.md)
- [setWakeOnMagicPacket](kernel/ioethernetcontroller/1811434-setwakeonmagicpacket.md)