Skip to content
This repository has been archived by the owner on Jul 14, 2021. It is now read-only.

Latest commit

 

History

History
53 lines (48 loc) · 3.26 KB

README.md

File metadata and controls

53 lines (48 loc) · 3.26 KB
Raw

SCEWL Bus Controller

The SCEWL Bus Controller implements the security and functionality of the SCEWL protocol and is one of two components your team must implement (the other being the SSS in /sss/). The SCEWL Bus Controller runs on a Stellaris lm3s6965 chip, which will be emulated using qemu-system-arm.

The SCEWL Bus Controller is split into a few files that may be of interest to you, although you are free to change any and all files in this directory as long as functional and build requirements are met:

  • controller.{c,h}: Implements the main functionality of the SCEWL Bus Controller. It contains main() and handles the message passing of the system
  • interface.{c,h}: Implements the interface to the hardware interfaces, reading and writing raw bytes. NOTE: it is your responsibility to format bytes written to the interfaces as specified in Section 4.6 of the rules. Malformed messages may be mangled or dropped completely by the network backend emulation. There is a good chance that you will not need to change interface.{c,h} in your design.
  • startup_gcc.c: Implements the system startup code, including initializing the stack and reset vectors. There is a good chance that you will not need to change startup_gcc.c in your design.
  • controller.ld: The linker script to set up memory regions. There is a good chance that you will not need to change controller.ld in your design.
  • lm3s/: Contains files to help interface with the lm3s6965 chip. There is a good chance that you will not need to change anything in lm3s/ in your design.
  • CMSIS/: Contains files to help interface with the ARM Cortex-M3 proccessor. There is a good chance that you will not need to change anything in CMSIS/ in your design.

On Adding Crypto

To aid with development, we have included Makefile rules and example code for using tiny-AES-c (see line 54 of the Makefile and lines 11 and 219 of controller.c). You are free to use the library for your crypto or simply use build process as a template for another crypto library of your choice.

If you choose to use a different crypto library, we recommend using the following steps to integrate it into your system. **NOTE: All added libraries must compile from the all rule of controller/Makefile to follow the functional requirements.

  1. Find a crypto library suitable for your embedded system. Make sure it does not require any system calls or dynamic memory allocation (i.e. malloc), as the controller runs on bare metal without an operating system
  2. Add the library to the controller/ directory either as a submodule in git or as a copy of the library source code
  3. Run the included tests of the library to verify it works properly on your machine before you integrate it with your code
  4. Add the directory path to the list of include paths (IPATH+=/path/to/crypto) in controller/Makefile
  5. Add the directory path to the list of source files (VPATH+=/path/to/crypto) in controller/Makefile
  6. Add each object file you wish to link to the LDFLAGS list (LDFLAGS+=${COMPILER}/source_file_name.o) in controller/Makefile
  7. Add each object file you wish to link to the all rule (all: ${COMPILER}/source_file_name.o) in controller/Makefile