pg_trgm vs. Solr ngram

Hello list

I'm pondering migrating an FTS application from Solr to Postgres, just
because we use Postgres for everything else.

The application is basically fgrep with a web frontend. However the
indexed documents are very computer network specific and contain a lot
of hyphenated hostnames with dot-separated domains, as well as IPv4 and
IPv6 addresses. In Solr I was using ngrams and customized the
TokenizerFactories until more or less only whitespace was as separator,
while [.:-_\d] remains part of the ngrams. This allows to search for
".12.255/32" or "xzy-eth5.example.org" without any false positives.

It looks like a straight conversion of this method is not possible since
the tokenization in pg_trgm is not configurable afaict. Is there some
other good method to search for a random substring including all the
punctuation using an index? Or a pg_trgm-style module that is more
flexible like the Solr/Lucene variant?

Or maybe hacking my own pg_trgm wouldn't be so hard and could be fun, do
I pretty much just need to change the emitted tokens or will this lead
to significant complications in the operators, indexes etc.?

thanks for any hints & cheers
Christian