aya-log - a logging library for eBPF programs

Overview

aya-log is a logging library for eBPF programs written using aya. Think of it as the log crate for eBPF.

Installation

User space

Add aya-log to Cargo.toml:

[dependencies]
aya-log = { git = "https://github.com/aya-rs/aya-log", branch = "main" }

eBPF side

Add aya-log-ebpf and ufmt to Cargo.toml:

[dependencies]
aya-log-ebpf = { git = "https://github.com/aya-rs/aya-log", branch = "main" }
ufmt = "0.1"

Example

Here's an example that uses aya-log in conjunction with the simplelog crate to log eBPF messages to the terminal.

User space code

use aya_log::BpfLogger;
use simplelog::{ColorChoice, ConfigBuilder, LevelFilter, TermLogger, TerminalMode};

BpfLogger::init(
    &mut bpf,
    TermLogger::new(
        LevelFilter::Trace,
        ConfigBuilder::new()
            .set_target_level(LevelFilter::Error)
            .set_location_level(LevelFilter::Error)
            .build(),
        TerminalMode::Mixed,
        ColorChoice::Auto,
    ),
).unwrap();

eBPF code

use aya_log_ebpf::info;

fn try_xdp_firewall(ctx: XdpContext) -> Result<u32, ()> {
    if let Some(port) = tcp_dest_port(&ctx)? {
        if block_port(port) {
            info!(&ctx, "❌ blocked incoming connection on port: {}", port);
            return Ok(XDP_DROP);
        }
    }

    Ok(XDP_PASS)
}