From 444d3196359be6bb82fdb6a0f5d5ba32fde4118a Mon Sep 17 00:00:00 2001 From: Paweł Redman Date: Sun, 14 Jun 2026 18:36:53 +0200 Subject: Initial commit --- site/content/schachtmeister2.typ | 66 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 site/content/schachtmeister2.typ (limited to 'site/content/schachtmeister2.typ') diff --git a/site/content/schachtmeister2.typ b/site/content/schachtmeister2.typ new file mode 100644 index 0000000..f000360 --- /dev/null +++ b/site/content/schachtmeister2.typ @@ -0,0 +1,66 @@ +#import "/common.typ": post + +#show: post.with( + title: "schachtmeister2", + date: datetime(year: 2020, month: 8, day: 15), +) + +`schachtmeister2` is a daemon for white- and blacklisting specified ISPs, hosting providers and so on. It was created for the Der Bunker Tremulous server to combat malicious players evading bans. + +The source code is available #link("https://redman.xyz/git/schachtmeister2")[here]. + +The daemon works by looking up a given IP address in WHOIS databases and reverse DNS records and analyzing the results. Its configuration file, `schachts.list`, is a list of keywords to be searched for along with a *partial rating*. The program's output, the *rating*, is the sum of partial ratings of all matched keywords. + += Usage + +Since the daemon is meant to be used with a Tremulous server, it communicates over UDP. The protocol is extremely simple. To query `schachtmeister2` send an UDP packet (port 1337) that looks like: + +``` +\xff\xff\xff\xffsm2query ADDRESS +``` + +Note the four leading `0xFF` bytes. The daemon will send a reply to the sender's address and port that will look like: + +``` +\xff\xff\xff\xffsm2reply ADDRESS RATING +``` + +Here's an example using BSD's netcat, asking for the rating of `8.8.8.8` (Google's DNS): + +``` +$ printf "\xff\xff\xff\xffsm2query 8.8.8.8" | nc -u 127.0.0.1 1337 +����sm2reply 8.8.8.8 0 +``` + += The list + +The daemon needs a list of keywords to operate meaningfully. The program looks for a file named `schachts.list` in its working directory. Below is an example list: + +``` +// a few known VPS and VPN providers +revdns -50 tcpvpn.com +revdns -50 vultr.com + +whois -50 "OVH" +whois -50 "DigitalOcean" +whois -50 "Digital Ocean" + +// Desala's ISP +revdns -10 .dynamic.chello.pl +``` + +The columns are: + +- Where to look for the substring: `revdns` or `whois`? +- The partial rating or how much the total rating changes if this substring is found. +- The substring to look for. Use quotation marks if you need spaces. The program does not support regular expressions yet. + +Whitespace doesn't matter but I recommend tabs for proper alignment. You can use C++-style one-line comments. + += Reloading on the fly + +Restarting the daemon clears its cache, so you might want to avoid it. To make `schachtmeister2` reload the list, send `SIGUSR1` to the process. + += Limitations + +This is one of those programs that I've written quickly, as crude prototypes, but have worked exceedingly well. As I couldn't be bothered to rewrite the program better, it's not very flexible and works well only in a single application. I might continue working on it if there's demand outside of Tremulous. -- cgit