---
title: getPacketBufferConstraints
framework: kernel
role: pseudoSymbol
path: kernel/ionetworkcontroller/1813962-getpacketbufferconstraints
---

# getPacketBufferConstraints

Gets the controller's packet buffer constraints.

## Declaration

```occ
virtual void getPacketBufferConstraints( 
 IOPacketBufferConstraints *constraints) const; 
```

## Parameters

- `constraints`: A pointer to an IOPacketBufferConstraints structure that this method is expected to initialize. See IOPacketBufferConstraints structure definition.

## Overview

Overview Called by start() to obtain the constraints on the memory buffer for each mbuf packet allocated through allocatePacket(). Drivers can override this method to specify the buffer constraints imposed by their bus mastering hardware. Note that outbound packets, those that originate from the network stack, are not currently subject to the constraints reported here.

## See Also

### Miscellaneous

- [allocatePacket](kernel/ionetworkcontroller/1813917-allocatepacket.md)
- [attachDebuggerClient](kernel/ionetworkcontroller/1813919-attachdebuggerclient.md)
- [attachInterface](kernel/ionetworkcontroller/1813921-attachinterface.md)
- [configureInterface](kernel/ionetworkcontroller/1813923-configureinterface.md)
- [copyMediumDictionary](kernel/ionetworkcontroller/1813924-copymediumdictionary.md)
- [copyPacket](kernel/ionetworkcontroller/1813925-copypacket.md)
- [createInterface](kernel/ionetworkcontroller/1813926-createinterface.md)
- [createOutputQueue](kernel/ionetworkcontroller/1813927-createoutputqueue.md)
- [createWorkLoop](kernel/ionetworkcontroller/1813928-createworkloop.md)
- [detachDebuggerClient](kernel/ionetworkcontroller/1813929-detachdebuggerclient.md)
- [detachInterface](kernel/ionetworkcontroller/1813930-detachinterface.md)
- [disable](kernel/ionetworkcontroller/1813931-disable.md)
- [disable(IONetworkInterface *)](kernel/ionetworkcontroller/1813932-disable.md)
- [disable(IOService *)](kernel/ionetworkcontroller/1813933-disable.md)
- [disablePacketFilter](kernel/ionetworkcontroller/1813934-disablepacketfilter.md)
- [doDisable](kernel/ionetworkcontroller/1813935-dodisable.md)
- [doEnable](kernel/ionetworkcontroller/1813936-doenable.md)
- [enable](kernel/ionetworkcontroller/1813937-enable.md)
- [enable(IONetworkInterface *)](kernel/ionetworkcontroller/1813938-enable.md)
- [enable(IOService *)](kernel/ionetworkcontroller/1813939-enable.md)
- [enablePacketFilter](kernel/ionetworkcontroller/1813940-enablepacketfilter.md)
- [executeCommand](kernel/ionetworkcontroller/1813941-executecommand.md)
- [free](kernel/ionetworkcontroller/1813942-free.md)
- [freePacket](kernel/ionetworkcontroller/1813943-freepacket.md)
- [getChecksumDemand](kernel/ionetworkcontroller/1813944-getchecksumdemand.md)
- [getChecksumSupport](kernel/ionetworkcontroller/1813945-getchecksumsupport.md)
- [getCommandClient](kernel/ionetworkcontroller/1813946-getcommandclient.md)
- [getCommandGate](kernel/ionetworkcontroller/1813947-getcommandgate.md)
- [getDebuggerLinkStatus](kernel/ionetworkcontroller/1813949-getdebuggerlinkstatus.md)
- [getFeatures](kernel/ionetworkcontroller/1813951-getfeatures.md)
- [getHardwareAddress](kernel/ionetworkcontroller/1813953-gethardwareaddress.md)
- [getMaxPacketSize](kernel/ionetworkcontroller/1813954-getmaxpacketsize.md)
- [getMediumDictionary](kernel/ionetworkcontroller/1813956-getmediumdictionary.md)
- [getMinPacketSize](kernel/ionetworkcontroller/1813957-getminpacketsize.md)
- [getOutputHandler](kernel/ionetworkcontroller/1813959-getoutputhandler.md)
- [getOutputQueue](kernel/ionetworkcontroller/1813960-getoutputqueue.md)
- [getPacketFilters](kernel/ionetworkcontroller/1813964-getpacketfilters.md)
- [getSelectedMedium](kernel/ionetworkcontroller/1813966-getselectedmedium.md)
- [handleClose](kernel/ionetworkcontroller/1813967-handleclose.md)
- [handleIsOpen](kernel/ionetworkcontroller/1813968-handleisopen.md)
- [handleOpen](kernel/ionetworkcontroller/1813969-handleopen.md)
- [init](kernel/ionetworkcontroller/1813970-init.md)
- [message](kernel/ionetworkcontroller/1813971-message.md)
- [newModelString](kernel/ionetworkcontroller/1813972-newmodelstring.md)
- [newRevisionString](kernel/ionetworkcontroller/1813973-newrevisionstring.md)
- [newVendorString](kernel/ionetworkcontroller/1813974-newvendorstring.md)
- [outputPacket](kernel/ionetworkcontroller/1813975-outputpacket.md)
- [prepare](kernel/ionetworkcontroller/1813976-prepare.md)
- [publishMediumDictionary](kernel/ionetworkcontroller/1813977-publishmediumdictionary.md)
- [publishProperties](kernel/ionetworkcontroller/1813978-publishproperties.md)
- [receivePacket](kernel/ionetworkcontroller/1813979-receivepacket.md)
- [registerWithPolicyMaker](kernel/ionetworkcontroller/1813980-registerwithpolicymaker.md)
- [releaseDebuggerLock](kernel/ionetworkcontroller/1813981-releasedebuggerlock.md)
- [releaseFreePackets](kernel/ionetworkcontroller/1813982-releasefreepackets.md)
- [replaceOrCopyPacket](kernel/ionetworkcontroller/1813983-replaceorcopypacket.md)
- [replacePacket](kernel/ionetworkcontroller/1813984-replacepacket.md)
- [reserveDebuggerLock](kernel/ionetworkcontroller/1813985-reservedebuggerlock.md)
- [selectMedium](kernel/ionetworkcontroller/1813986-selectmedium.md)
- [selectMediumWithName](kernel/ionetworkcontroller/1813987-selectmediumwithname.md)
- [sendPacket](kernel/ionetworkcontroller/1813988-sendpacket.md)
- [setChecksumResult](kernel/ionetworkcontroller/1813989-setchecksumresult.md)
- [setDebuggerMode](kernel/ionetworkcontroller/1813990-setdebuggermode.md)
- [setHardwareAddress](kernel/ionetworkcontroller/1813991-sethardwareaddress.md)
- [setLinkStatus](kernel/ionetworkcontroller/1813992-setlinkstatus.md)
- [setMaxPacketSize](kernel/ionetworkcontroller/1813993-setmaxpacketsize.md)
- [setSelectedMedium](kernel/ionetworkcontroller/1813994-setselectedmedium.md)
- [start](kernel/ionetworkcontroller/1813995-start.md)
- [stop](kernel/ionetworkcontroller/1813996-stop.md)
- [systemWillShutdown](kernel/ionetworkcontroller/1813997-systemwillshutdown.md)