TCP/IP Protocol stack without an OS

Question

I'm looking for a TCP/IP stack that can be used without an OS. Our customer has an "aversion" to interrupts and doesn't want a real OS on a embedded board we're building. It's desirable to move as much of the functionality to FPGA as possible due to the fact we will be only using a 50 to 100 MHz Arm. And I'm pretty sure GPL licensed stuff won't be acceptable for this client. (Due to the legal quagmire associated with it. They expect to have full unrestricted rights to the software once it's complete.)

Answer 1

uIP (micro IP) and lwIP (lightweight IP) are both candidates worth consideration. According to the original developer of both stacks - Adam Dunkel - one of the primary differences between the two is: "lwIP is larger than uIP, but provides better throughput". Both stacks employ a modified BSD license and have been used in commercial products.

Answer 2

This doesn't necessarily answer your question the way you want it answered (it's not in the comments section since my diatribe is probably going to be too long). However, I think it may still be helpful.

A couple of points. I think you should re-educate your clients on the benefits and costs of interrupts. Interrupts are a very efficient way of handling device control and, unless you're meticulous about your coding, you're unlikely to match the performance with non-interrupt-driven code.

Secondly, using GPL software will give them full unrestricted rights to the software, it just won't allow them to restrict others. If you mean they do want to restrict others then I'd be asking why they think they should have the right to use the labours of others without any give-back.

You may well be able to find a TCP stack under a more permissive licence than GPL (allowing them to effectively close-source it). If you have a C compiler for your FPGA, you can possibly look into uIP which has a very permissive licence from a brief look:

Copyright (c) 2001-2006, Adam Dunkels and the Swedish Institute of Computer Science

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

That's it, no "must release under GPL" or any other viral clauses, and the only attribution is the inclusion of the copyright notice.