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History

Michal Rostecki 628b473e09 ebpf: Ensure the bounds of log buffer eBPF verifier rejects programs which are not checking the bounds of the log buffer before writing any arguments. This change ensures that written log arguments. In practice, it means that doing this kind of checks is not going to be needed in eBPF program code anymore: `33a1aee2ea/echo-ebpf/src/main.rs (L47)` Tested on: `876f8b4551` Signed-off-by: Michal Rostecki <vadorovsky@gmail.com>		3 years ago
..
.cargo	git add .cargo and xtask	3 years ago
aya-log	aya-log, aya-log-common: start next development iteration 0.1.10-dev.0	3 years ago
aya-log-common	common: Bump the buffer size	3 years ago
ebpf	ebpf: Ensure the bounds of log buffer	3 years ago
xtask	xtask: do not release	3 years ago
.gitignore	Initial commit	3 years ago
Cargo.toml	Initial commit	3 years ago
README.md	Simplify BpfLogger::init	3 years ago
release.toml	Add cargo-release config	3 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)
}