[syslinux] EFI: PXE: "My IP is 0.0.0.0"

[Patrick Masotta]

>>>
 > It does contain a Net but there are 2 issues with SNP:
 > 1) The interface is different than UDPv4/TCPv4 protocols; this imply lot of code.

 Not as much as you
 may think.  We already have lwIP implemented into lpxelinux.0.  It's more a matter of using more glue.
 
 > 2) SNP has its non-blocking transmit issues ; see "Flaws in the design" at
 >  https://wiki.linaro.org/LEG/Engineering/Kernel/UEFI/UEFI_Network_Driver#Flaws_in_the_design
  certainly gives some things to think about.
 
 As a side note, I'd expect anything that used SNP should be able to
 shut everything else off and have to implement enough of a TCP/IP stack to be proper for
 its uses (ie no need to implement TCP or respond to TCP if it doesn't use TCP yet
 should respond to ARP requests).
>>>

OK, at the moment the updated code should be able to deal with cases #2 and #3
Let's put a pin on SNP for case #1 and see what the multi-NIC users report from the 
current patch. What do you think?
 
 
>>>
 >
 > So far I've seen MNPSb is only available when the rest of SBs are also present then
 > it makes no sense embracing a new MNP protocol when UDPv4Sb and TCPv4Sb are also
 > available.
 
 Correct, MNPSb is the parent.  We'd only use it if we wanted to create
 a new protocol like a TCP replacement which I expect is out of scope.
 
 My point is that unless the rule was set early, I'd expect to
 eventually find an oddball client where UDPSb and TCPSb live on different 
 EFI_HANDLEs (but presumably still under an MNPSb).
<<<

The current code either looks for UDPSb handles (or TCPSb depending on the received bgiud),
then it really does not matter if UDPSb and TCPSb are created under different handles.
As soon as I get the array of UDPSb (or TCPSb ) handles I parse their associated 
Path Protocol looking for the matching MAC. 
 
>>>
 > I also wonder if UEFI firmware w/o SB protocols is really UEFI compliant...
 > i.e the Elitebook 8460p is an early 2011 model that probably should receive a firmware update
 > including the missing SB protocols...
 
 What firmware version is loaded?  Available?
<<<

The last one;  	F.60 Rev.A(31 Mar 2015)


>>> For absolute hilarity, Google "8460p firmware EFI".  Your forum post was on top for me. <<<

Yes; I know... HP silence says it all; they know they're guilty ;-)
http://h30434.www3.hp.com/t5/Notebook-Operating-Systems-and-Software/EFI-firmware-bug-on-HP-EliteBook-2560p-8460p/td-p/4931486


>>> 
> I thought of it but I do not know if there's really much to get here;
 > i.e. in a 4 NIC PC the parsing only involves 4 UDPv4Sb (or TCPv4Sb) handles.
 > Anyway it can definitely be done if necessary.
 
 It's also a
 question of how fast the firmware bothers to be.
 Considering our rate, this in theory shouldn't matter.
<<<

agreed


>>>
Oh how fun.  UEFI Specifications version 2.0 states "An
EFI_PXE_BASE_CODE_PROTOCOL will be layered on top of an
EFI_SIMPLE_NETWORK_PROTOCOL protocol in order to perform packet level
transactions." while version 2.1 states "An EFI_PXE_BASE_CODE_PROTOCOL
will be layered on top of an EFI_MANAGED_NETWORK_PROTOCOL protocol in
order to perform packet level transactions."
>>>

Could this be the reason why in the past Pxebc and the SBs where attached to different handles?? mmhhh
I have to admit; UEFI development is a bit messy...


Best,
Patrick