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History

Michal Rostecki ec31526de1 Format arguments in userspace This change moves away argument formatting from eBPF to the userspace. eBPF part of aya-log writes unformatted log message and all arguments to the perf buffer and the userspace part of aya-log is formatting the message after receiving all arguments. Aya-based project to test this change: https://github.com/vadorovsky/aya-log-example Fixes: #4 Signed-off-by: Michal Rostecki <vadorovsky@gmail.com> Signed-off-by: Tuetuopay <tuetuopay@me.com> Co-authored-by: Tuetuopay <tuetuopay@me.com>		4 years ago
..
src	Format arguments in userspace	4 years ago
Cargo.toml	Format arguments in userspace	4 years ago
README.md	Add copy of README.md inside aya-log/	4 years ago

README.md

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 to Cargo.toml:

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

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

TermLogger::init(
    LevelFilter::Debug,
    ConfigBuilder::new()
        .set_target_level(LevelFilter::Error)
        .set_location_level(LevelFilter::Error)
        .build(),
    TerminalMode::Mixed,
    ColorChoice::Auto,
)
.unwrap();

// Will log using the default logger, which is TermLogger in this case
BpfLogger::init(&mut bpf).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)
}