The milter library provides Rust bindings to libmilter, the sendmail mail filter API.
This library serves the creation of milters: mail filtering applications that can be integrated with MTAs (mail servers) such as [Postfix].
This crate requires the milter C library (libmilter) to be available.
On Debian and Ubuntu, install the package libmilter-dev.
If your distribution does not provide pkg-config metadata for libmilter, try
using the provided milter.pc file when executing the build:
PKG_CONFIG_PATH=. cargo build
The integration tests of this crate require the third-party miltertest utility
in order to exercise the test milters. This program can be found among the
OpenDKIM command-line tools.
On Debian and Ubuntu, install either the miltertest or the opendkim-tools
package (only required when working on the milter crate itself).
The main use case of this library is creating milter applications, that is,
executable programs with a main function.
Include [libc] in addition to milter in Cargo.toml:
toml
[dependencies]
milter = "0.2"
libc = "0.2"
Here’s a simple milter application that logs client IP addresses:
```rust use milter::{on_connect, Context, Milter, Status}; use std::net::SocketAddr;
fn handleconnect(
_: Context<()>,
_: &str,
socketaddr: Option
Status::Continue
}
fn main() { Milter::new("unix:/run/ipmilter.sock") .name("IPMilter") .onconnect(connectcallback) .run() .expect("milter execution failed"); } ```
Refer to the [API documentation] for complete usage instructions.
This package includes an example milter inspect, which prints all arguments
and macros for each stage, and so is immediately useful as a view into how
milters operate, and what shape the received data has.
Start the inspect example by passing a socket spec with an unused port (again,
if your distribution does not provide the requisite pkg-config metadata, you may
need to adjust PKG_CONFIG_PATH, see above):
cargo run --example inspect inet:3000@localhost
After the example milter has started, configure the MTA – Postfix – to connect
to the milter. Add the following parameters to /etc/postfix/main.cf, and
reload the Postfix configuration:
smtpd_milters = inet:localhost:3000
non_smtpd_milters = $smtpd_milters
The example milter will then print everything it receives from Postfix.
Copyright © 2020 David Bürgin
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.