Re: [PATCH v1] NetworkPkg/UefiPxeBcDxe: Fix PXE_BOOT_SERVERS usage in boot info parse flow

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

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

> -----Original Message-----
> From: Maciej Rabeda <maciej.rabeda@linux.intel.com>
> Sent: 2020年8月20日 0:54
> To: devel@edk2.groups.io
> Cc: Wu, Jiaxin <jiaxin.wu@intel.com>; Fu, Siyuan <siyuan.fu@intel.com>
> Subject: [PATCH v1] NetworkPkg/UefiPxeBcDxe: Fix PXE_BOOT_SERVERS usage
> in boot info parse flow
> 
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2876
> 
> According to PXE 2.1 spec, DHCP option 43, tag 6 (PXE_DISCOVERY_CONTROL),
> bit 3 specifies whether PXE client should use/accept TFTP servers defined
> within PXE_BOOT_SERVERS list (tag 8). This bit was not being taken into
> account when choosing boot server IP in PxeBcDhcp4BootInfo().
> 
> Cc: Jiaxin Wu <jiaxin.wu@intel.com>
> Cc: Siyuan Fu <siyuan.fu@intel.com>
> Signed-off-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
> ---
>  NetworkPkg/UefiPxeBcDxe/PxeBcBoot.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/NetworkPkg/UefiPxeBcDxe/PxeBcBoot.c
> b/NetworkPkg/UefiPxeBcDxe/PxeBcBoot.c
> index d062a526077b..ed9bca0f7de3 100644
> --- a/NetworkPkg/UefiPxeBcDxe/PxeBcBoot.c
> +++ b/NetworkPkg/UefiPxeBcDxe/PxeBcBoot.c
> @@ -499,12 +499,16 @@ PxeBcDhcp4BootInfo (
> 
> 
>    //
> 
>    // Parse the boot server address.
> 
> -  // If prompt/discover is disabled, get the first boot server from the boot
> servers list.
> 
> -  // Otherwise, parse the boot server Ipv4 address from next server address field
> in DHCP header.
> 
> +  // If prompt/discover is disabled, server list should be used and is present
> (DHCP option 43),
> 
> +  // get the first boot server from the boot servers list.
> 
> +  // Otherwise, parse the boot server IPv4 address from next server address
> field in DHCP header.
> 
>    // If all these fields are not available, use option 54 instead.
> 
>    //
> 
>    VendorOpt = &Cache4->VendorOpt;
> 
> -  if (IS_DISABLE_PROMPT_MENU (VendorOpt->DiscoverCtrl) &&
> IS_VALID_BOOT_SERVERS (VendorOpt->BitMap)) {
> 
> +  if (IS_DISABLE_PROMPT_MENU (VendorOpt->DiscoverCtrl) &&
> 
> +      IS_VALID_BOOT_SERVERS (VendorOpt->BitMap) &&
> 
> +      IS_ENABLE_USE_SERVER_LIST (VendorOpt->DiscoverCtrl))
> 
> +  {
> 
>      Entry = VendorOpt->BootSvr;
> 
>      if (VendorOpt->BootSvrLen >= sizeof (PXEBC_BOOT_SVR_ENTRY) && Entry-
> >IpCnt > 0) {
> 
>        CopyMem (
> 
> --
> 2.24.0.windows.2