| commit | 8f367fc0e44ff19150608bae6e5742ae4d3d0fe2 | [log] [tgz] |
|---|---|---|
| author | Will Drewry <wad@google.com> | Thu Mar 30 22:07:48 2017 -0500 |
| committer | Will Drewry <wad@google.com> | Mon Apr 03 08:39:49 2017 -0500 |
| tree | e343437ce2474da1cd2b11483773d0d9ac3555fb | |
| parent | b502e59c5325769d28f2f6f41050e36255b84738 [diff] |
libese-hw: move transceive to scattergather This change migrates hardware callbacks for transceive to a scatter-gather interface, updates the tests, and adds specific tests for ese_sg. Additionally, a small amount of code reorganization is included, like moving API to ESE_API and into sysdeps to reduce some duplicatation as well as removing dead code (two sysdeps.h). As the T=1 implementation already copies data during framing, it was becoming ungainly to recopy data to frame APDUs which will then be copied only to be reframed. This is especially true for extended APDUs as the payloads may be up to 65k. Change-Id: I37f586645965d32577f8b724dbe41c9041439887 Test: ese_replay still works (open channel, select, close channel) Bug: 34467857
Document last updated: 13 Jan 2017
libese provides a minimal transport wrapper for communicating with embedded secure elements. Embedded secure elements typically adhere to smart card standards whose translation is not always smooth when migrated to an always connected bus, like SPI. The interfaces exposed by libese should enable higher level "terminal" implementations to be written on top and/or a service which provides a similar interface.
Behind the interface, libese should help smooth over the differences between eSEs and smart cards use in the hardware adapter implementations. Additionally, a T=1 implementation is supplied, as it appears to be the most common wire transport for these chips.
Public client interface for Embedded Secure Elements.
Prior to use in a file, import all necessary variables with:
ESE_INCLUDE_HW(SOME_HAL_IMPL);
Instantiate in a function with:
ESE_DECLARE(my_ese, SOME_HAL_IMPL);
or
struct EseInterface my_ese = ESE_INITIALIZER(SOME_HAL_IMPL);
or
struct EseInterface *my_ese = malloc(sizeof(struct EseInterface)); ... ese_init(my_ese, SOME_HAL_IMPL);
To initialize the hardware abstraction, call:
ese_open(my_ese);
To release any claimed resources, call
ese_close(my_ese)
when interface use is complete.
To perform a transmit-receive cycle, call
ese_transceive(my_ese, ...);
with a filled transmit buffer with total data length and an empty receive buffer and a maximum fill length. A negative return value indicates an error and a hardware specific code and string may be collected with calls to
ese_error_code(my_ese); ese_error_message(my_ese);
The EseInterface is not safe for concurrent access. (Patches welcome! ;).
libese is broken into multiple pieces:
libese provides the headers and wrappers for writing libese clients and for implementing hardware backends. It depends on a backend being provided as per libese-hw and on libese-sysdeps.
libese-sysdeps provides the system level libraries that are needed by libese provided software. If libese is being ported to a new environment, like a bootloader or non-Linux OS, this library may need to be replaced. (Also take a look at libese/include/ese/log.h for the macro definitions that may be needed.)
libese-hw provides existing libese hardware backends.
libese-teq1 provides a T=1 compatible transcieve function that may be used by a hardware backend. It comes with some prequisites for use, such as a specifically structured set of error messages and EseInteface pad usage, but otherwise it does not depends on any specific functionality not abstracted via the libese EseOperations structure.
There are two test backends, fake and echo, as well as one real backend for the NXP PN80T/PN81A.
The NXP backends support both a direct kernel driver and a Linux SPIdev interface.