Re: MdeModulePkg/UefiPxeBcDxe: Question about IcmpErrorListenHandler in PxeBcImpl.c

["Wu, Jiaxin" <jiaxin.wu@intel.com>]

Hi Gary, 

IcmpErrorRcvToken is only used to get ICMP error from IP layer, and the data will be copied to Mode->IcmpError. So, I think the RxData should be recycled. 

Besides, EFI_IP_PROTO_ICMP should be also checked in the call function but currently it's not:

  if (!EFI_IP4_EQUAL (&RxData->Header->DestinationAddress, &Mode->StationIp.v4)) {
    //
    // The dest address is not equal to Station Ip address, discard it.
    //
    goto CleanUp;
  }

  +if (&RxData->Header->Protocol != EFI_IP_PROTO_ICMP) {
  +//
  +// The protocol value in the header of the receveid packet should be EFI_IP_PROTO_ICMP.
  +//
  +goto CleanUp;
  +}

Thanks the report.

Thanks,
Jiaxin



> -----Original Message-----
> From: Guo Heyi [mailto:heyi.guo@linaro.org]
> Sent: Thursday, December 7, 2017 12:07 PM
> To: edk2-devel@lists.01.org
> Cc: Zeng, Star <star.zeng@intel.com>; Dong, Eric <eric.dong@intel.com>; Ni,
> Ruiyu <ruiyu.ni@intel.com>; Fu, Siyuan <siyuan.fu@intel.com>; Wu, Jiaxin
> <jiaxin.wu@intel.com>
> Subject: MdeModulePkg/UefiPxeBcDxe: Question about
> IcmpErrorListenHandler in PxeBcImpl.c
> 
> Hi folks,
> 
> In PxeBcImpl.c, we have IcmpErrorListenHandler which seems to process
> ICMP errors. But in EfiPxeBcStart function, we can see Private-
> >IcmpErrorRcvToken.Event is only a common event and Ip4->Receive is
> called to receive IP4 packets. So will IcmpErrorListenHandler receive all IP4
> packets belonging to this network interface, or will it only receive ICMP error
> packets? If it is the latter situation, how do we make it?
> 
> The background of this question is that when we flush the network with
> deprecated ICMP packets (type 15, 16, ...), RxData will not be recycled and
> the list of UEFI events becomes longer and longer, which finally impacts
> system performance a lot. If only error ICMP will be received by
> IcmpErrorListenHandler, we'd like to patch it as below:
> 
> diff --git a/MdeModulePkg/Universal/Network/UefiPxeBcDxe/PxeBcImpl.c
> b/MdeModulePkg/Universal/Network/UefiPxeBcDxe/PxeBcImpl.c
> index 6d4f33f..f74b264 100644
> --- a/MdeModulePkg/Universal/Network/UefiPxeBcDxe/PxeBcImpl.c
> +++ b/MdeModulePkg/Universal/Network/UefiPxeBcDxe/PxeBcImpl.c
> @@ -216,8 +216,6 @@ IcmpErrorListenHandlerDpc (
>      CopiedPointer += CopiedLen;
>    }
> 
> -  goto Resume;
> -
>  CleanUp:
>    gBS->SignalEvent (RxData->RecycleSignal);
> 
> We tested and it worked, but we are still not sure whether it will impact
> other code in the network stack.
> 
> Please let me know your comments.
> 
> Thanks,
> 
> Gary (Heyi Guo)