Re: [Patch v2] MdeModulePkg: Free NET_BUF data after it is sent out to avoid memory leak

["Fu, Siyuan" <siyuan.fu@intel.com>]

Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>

> -----Original Message-----
> From: Wang, Fan
> Sent: Monday, November 27, 2017 2:44 PM
> To: edk2-devel@lists.01.org
> Cc: Wu, Jiaxin <jiaxin.wu@intel.com>; Ye, Ting <ting.ye@intel.com>; Fu,
> Siyuan <siyuan.fu@intel.com>; Wang, Fan <fan.wang@intel.com>
> Subject: [Patch v2] MdeModulePkg: Free NET_BUF data after it is sent out
> to avoid memory leak
> 
> V2:
> * Since packet has already been referred by DhcpSb->LastPacket, and will
> be
> freed when sending another packet or clean up, there is no need to add an
> extra free function in NetbufFromExt.
> 
> Cc: Jiaxin Wu <jiaxin.wu@intel.com>
> Cc: Ye Ting <ting.ye@intel.com>
> Cc: Fu Siyuan <siyuan.fu@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Wang Fan <fan.wang@intel.com>
> ---
>  MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Impl.h | 12 ++++++++++++
>  MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Io.c   | 13 +++++--------
>  2 files changed, 17 insertions(+), 8 deletions(-)
> 
> diff --git a/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Impl.h
> b/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Impl.h
> index e546a08..57f6d5e 100644
> --- a/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Impl.h
> +++ b/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Impl.h
> @@ -182,10 +182,22 @@ VOID
>  DhcpCleanConfigure (
>    IN OUT EFI_DHCP4_CONFIG_DATA  *Config
>    );
> 
>  /**
> +  Callback of Dhcp packet. Does nothing.
> +
> +  @param Arg           The context.
> +
> +**/
> +VOID
> +EFIAPI
> +DhcpDummyExtFree (
> +  IN VOID                   *Arg
> +  );
> +
> +/**
>    Set the elapsed time based on the given instance and the pointer to the
>    elapsed time option.
> 
>    @param[in]      Elapsed       The pointer to the position to append.
>    @param[in]      Instance      The pointer to the Dhcp4 instance.
> diff --git a/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Io.c
> b/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Io.c
> index 3898223..54a610a 100644
> --- a/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Io.c
> +++ b/MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Io.c
> @@ -1357,17 +1357,16 @@ DhcpSendMessage (
>      &DhcpSb->ClientAddressSendOut[0],
>      &Packet->Dhcp4.Header.ClientHwAddr[0],
>      Packet->Dhcp4.Header.HwAddrLen
>      );
> 
> -
>    //
>    // Wrap it into a netbuf then send it.
>    //
>    Frag.Bulk = (UINT8 *) &Packet->Dhcp4.Header;
>    Frag.Len  = Packet->Length;
> -  Wrap      = NetbufFromExt (&Frag, 1, 0, 0, DhcpReleasePacket, Packet);
> +  Wrap      = NetbufFromExt (&Frag, 1, 0, 0, DhcpDummyExtFree, NULL);
> 
>    if (Wrap == NULL) {
>      FreePool (Packet);
>      return EFI_OUT_OF_RESOURCES;
>    }
> @@ -1397,11 +1396,10 @@ DhcpSendMessage (
>      EndPoint.LocalAddr.Addr[0]  = DhcpSb->ClientAddr;
>      UdpIo                       = DhcpSb->LeaseIoPort;
>    }
> 
>    ASSERT (UdpIo != NULL);
> -  NET_GET_REF (Wrap);
> 
>    Status = UdpIoSendDatagram (
>               UdpIo,
>               Wrap,
>               &EndPoint,
> @@ -1409,11 +1407,11 @@ DhcpSendMessage (
>               DhcpOnPacketSent,
>               DhcpSb
>               );
> 
>    if (EFI_ERROR (Status)) {
> -    NET_PUT_REF (Wrap);
> +    NetbufFree (Wrap);
>      return EFI_ACCESS_DENIED;
>    }
> 
>    return EFI_SUCCESS;
>  }
> @@ -1452,16 +1450,16 @@ DhcpRetransmit (
>    //
>    // Wrap it into a netbuf then send it.
>    //
>    Frag.Bulk = (UINT8 *) &DhcpSb->LastPacket->Dhcp4.Header;
>    Frag.Len  = DhcpSb->LastPacket->Length;
> -  Wrap      = NetbufFromExt (&Frag, 1, 0, 0, DhcpReleasePacket, DhcpSb-
> >LastPacket);
> +  Wrap      = NetbufFromExt (&Frag, 1, 0, 0, DhcpDummyExtFree, NULL);
> 
>    if (Wrap == NULL) {
>      return EFI_OUT_OF_RESOURCES;
>    }
> -
> +
>    //
>    // Broadcast the message, unless we know the server address.
>    //
>    EndPoint.RemotePort         = DHCP_SERVER_PORT;
>    EndPoint.LocalPort          = DHCP_CLIENT_PORT;
> @@ -1475,22 +1473,21 @@ DhcpRetransmit (
>      UdpIo                       = DhcpSb->LeaseIoPort;
>    }
> 
>    ASSERT (UdpIo != NULL);
> 
> -  NET_GET_REF (Wrap);
>    Status = UdpIoSendDatagram (
>               UdpIo,
>               Wrap,
>               &EndPoint,
>               NULL,
>               DhcpOnPacketSent,
>               DhcpSb
>               );
> 
>    if (EFI_ERROR (Status)) {
> -    NET_PUT_REF (Wrap);
> +    NetbufFree (Wrap);
>      return EFI_ACCESS_DENIED;
>    }
> 
>    return EFI_SUCCESS;
>  }
> --
> 1.9.5.msysgit.1