RFC Gateway Service + Python 3 Migration

[randomstr1ng]

This PR adds an RFC Gateway honeypot service and migrates the codebase to Python 3.

RFC Gateway (new)

• Full RFC gateway implementation that emulates an SAP application server gateway
• Handles login handshakes, FM/RFM calls, and system info requests
• Extracts and descrambles credentials from CPIC login traffic
• Captures multi stage attacks by simulating FM & RFM behaviour
• Ships with bundled DDIC and RFM catalogs

Other changes

• Python 3 migration across the entire codebase
• Message Server: better alignment with pysap, improved logging
• SAPRouter: bug fixes
• Docker and CI pipeline updates
• Docs for Gateway, ICM, and Message Server services

Before leaving draft status:

• Check & validate CI Pipeline
• Check and Validate Docker Images
• Merge RFC additions (and others) into pysap project from local fork!

[DaCodah]

Hi @randomstr1ng, really like where this PR is going. The Python 3 migration and the new RFC gateway are great additions. I pulled your rfc-gateway branch locally to help validate the CI item on your todo list, and wanted to share what I found.

1. One leftover six import blocks the test suite. tests/services/saprouter_test.py still has from six.moves import range, but six was (correctly) dropped from requirements.txt during the migration, so pytest fails at collection with ModuleNotFoundError: No module named 'six'. In Python 3 the line isn't needed at all, since the built-in range covers the one usage in that file. Removing it gets the suite to 32 passed locally.

2. The PR isn't buildable from outside without pysap-dev. requirements.txt pins pysap>=0.1.20.dev0, which isn't on PyPI (only up to 0.1.19 is published). I found it lives in your pysap-dev fork (0.2.0.dev0) and installing from there works, but anyone trying the PR fresh will hit a hard wall here. This lines up with your "merge RFC additions into pysap" todo, just flagging how it currently affects reproducibility.

3. Minor: newer pytest emits PytestReturnNotNoneWarning for the test_suite functions that return a TestSuite instead of using assert. Not blocking anything, just noise, and clearly out of scope here.

Happy to send the six fix as a small PR against your rfc-gateway branch if that's useful, or just leave it here for you to fold in. Whatever works best for you. Either way, nice work on this.

[randomstr1ng]

submitted the PR to pysap to add required modules and functions: OWASP/pysap#93