Crate ip2asn

A high-performance, memory-efficient Rust crate for mapping IP addresses to Autonomous System (AS) information with sub-microsecond lookups.

The core of the crate is the IpAsnMap, a read-optimized data structure constructed using a flexible Builder. The builder can ingest data from files, network streams, or in-memory buffers, and can operate in either a strict mode that errors on malformed lines or a resilient mode that skips them. Lookups are performed in sub-microsecond time, returning a lightweight view of the ASN details. The crate provides detailed Error and Warning types for robust error handling.

All public data structures are marked as #[non_exhaustive] to allow for future additions without breaking backward compatibility. This means you must use the .. syntax in match patterns on enums and struct instantiations.

Quick Start

use ip2asn::{Builder, IpAsnMap};
use ip_network::IpNetwork;
use std::net::IpAddr;

fn main() -> Result<(), ip2asn::Error> {
    // A small, in-memory TSV data source for the example.
    let data = "31.13.64.0\t31.13.127.255\t32934\tUS\tFACEBOOK-AS";

    // Build the map from a source that implements `io::Read`.
    let map = Builder::new()
        .with_source(data.as_bytes())?
        .build()?;

    // Perform a lookup.
    let ip: IpAddr = "31.13.100.100".parse().unwrap();
    if let Some(info) = map.lookup(ip) {
        assert_eq!(info.network, "31.13.64.0/18".parse::<IpNetwork>().unwrap());
        assert_eq!(info.asn, 32934);
        assert_eq!(info.country_code, "US");
        assert_eq!(info.organization, "FACEBOOK-AS");
        println!(
            "{} -> AS{} {} ({}) in {}",
            ip, info.asn, info.organization, info.country_code, info.network
        );
    }

    Ok(())
}

Modules

parser

Line-by-line parsing logic for IP-to-ASN data. Contains the logic for parsing a single line of the iptoasn.com TSV data.

range

IP range to CIDR conversion logic.

types

Core data structures for ASN records. This module contains the primary data structures for the ip2asn crate, with a focus on memory efficiency and query performance.

Structs

AsnInfo

An owned struct containing ASN information for an IP address.

AsnInfoView

A lightweight, read-only view into the ASN information for an IP address. This struct is returned by the lookup method.

Builder

A builder for configuring and loading an IpAsnMap.

IpAsnMap

A read-optimized, in-memory map for IP address to ASN lookups. Construction is handled by the Builder.

Enums

Error

The primary error type for the crate.

ParseErrorKind

The specific kind of error that occurred during line parsing.

Warning

A non-fatal warning for a skipped line during parsing.