Respdiff

Respdiff is an abbreviation from "response differences" used as name for set of tools allowing to gather answers to DNS queries from DNS servers and compare them based on specified criteria.

Installation

$ git clone https://gitlab.nic.cz/knot/respdiff.git
$ cd respdiff
$ pip3 install -r requirements.txt

Respdiff toolchain requires Python 3.5.2+. There are also some Python package dependencies that are listed in requirements.txt. If you'd prefer to use your distribution packages, please install them manually instead of using pip3.

Usage

Please note that this is very basic use-case where nothing is prepared beforehand.

$ ./qprep.py "${DIR}" < list_of_queries_in_text_format
$ ./orchestrator.py "${DIR}"
$ ./msgdiff.py "${DIR}"
$ ./diffsum.py "${DIR}" > "${DIR}"/"${DIR}".txt

You can also re-run msgdiff.py and diffsum.py using different configuration.

Advanced usage

• Customize respdiff.cfg (see instructions in the file).
• All executable scripts in the project's repository are tools for with a specific purpose. You can find their documentation in doc/ and --help.
• Queries and answeres can be gathered with a different tool (e.g. dnsjit) and read from LMDB (see doc/lmdb_format.rst for description of the used binary format.
• Some tools have a more performant alternative, see respdiff-rs.

Overview

Respdiff is conceptually chain of independent tools:

1. qprep: generate queries in wire format and store to LMDB
2. orchestrator: send pre-generated wire format to servers and gather answers to LMDB
3. msgdiff: compare DNS answers
4. diffrepro: attempt to reproduce the differences
5. diffsum: summarize differences into textual and machine readable report
6. histogram: plot graph of answer latencies
7. sumcmp: compare a new diffsum report to a reference one
8. sumstat: generate statistics from multiple diffsum reports
9. statcmp: plot and compare statistics and reports

Changelog

• 2019-07-03: histrogram.py - -o/--output now expects directory instead of a single file, -f/--format can be used to specify image format
• 2018-08-30: JSON datafile format changed: other_disagreements now includes a list of all affected queries. Older reports will incorrectly report 0 for this field. (Can be fixed by re-creating reports with msgdiff.py).
• 2018-08-21: qname, qcase and qtype field comparisons were removed. question comparison now performs all these check in a case sensitive manner. Remove these checks from criteria and field_weights in respdiff.cfg.
• 2018-08-16: new dependency scipy added to requirements.txt
• 2018-06-01: reorganized tools and created a new git repo with cleaned-up history