[tailhook]

Well, for many protocols it easy. I had written (a useful subset of) mysql protocol parser in a weekend. Sure, this is in Python, so reimplement it in C is much harder, still not years or so. Many protocols: mongodb, redis, memcached, beanstalk, etc, are much simpler.

There are protocols that take months and years, but they are not so ubiquitous (with the obvious exception of HTTP, which is really complex and ubiquitous). So they may be developed after basic tools are in place.

[rumcajz]

Parsers are generally easy, I was thimking more about implementation stuff like: How can we pipe input from one protocol to another protocol on top of it? How to poll on a user-space protocol? How to integrate it with foreign event loops? If in user space, how to handle process termination if there's still data in tx queue? How to handle many different peers at once without having to create a separate thread for each of them? Et c.