community-id 0.2.4

use std::collections::HashMap;
use std::sync::LazyLock;

const ECHO_REPLY: u16 = 0;
const ECHO: u16 = 8;
const RTR_ADVERT: u16 = 9;
const RTR_SOLICIT: u16 = 10;
const TSTAMP: u16 = 13;
const TSTAMP_REPLY: u16 = 14;
const INFO: u16 = 15;
const INFO_REPLY: u16 = 16;
const MASK: u16 = 17;
const MASK_REPLY: u16 = 18;

/// icmp type mapping
///
/// ref <https://github.com/corelight/pycommunityid/blob/master/communityid/icmp.py>
static ICMP_TYPE_MAPPING: LazyLock<HashMap<u16, u16>> = LazyLock::new(|| {
    HashMap::from([
        (ECHO, ECHO_REPLY),
        (ECHO_REPLY, ECHO),
        (TSTAMP, TSTAMP_REPLY),
        (TSTAMP_REPLY, TSTAMP),
        (INFO, INFO_REPLY),
        (INFO_REPLY, INFO),
        (RTR_SOLICIT, RTR_ADVERT),
        (RTR_ADVERT, RTR_SOLICIT),
        (MASK, MASK_REPLY),
        (MASK_REPLY, MASK),
    ])
});

pub(crate) fn get_port_equivalents(mtype: u16, mcode: u16) -> (u16, u16, bool) {
    match ICMP_TYPE_MAPPING.get(&mtype) {
        Some(v) => (mtype, *v, false),
        None => (mtype, mcode, true),
    }
}

#[cfg(test)]
mod tests {
    use std::net::Ipv4Addr;

    use crate::calculate_community_id;

    #[test]
    fn test_icmp_with_ports() {
        let id = calculate_community_id(
            0,
            Ipv4Addr::new(10, 10, 10, 10).into(),
            Ipv4Addr::new(10, 10, 10, 10).into(),
            Some(0),
            Some(8),
            1,
            Default::default(),
        );

        assert_eq!("1:4MHSMLtBw+4q7Wke3ztBRVwtgt0=", id.unwrap());
    }

    #[test]
    fn test_icmp_without_ports() {
        let id = calculate_community_id(
            0,
            Ipv4Addr::new(10, 10, 10, 10).into(),
            Ipv4Addr::new(10, 10, 10, 10).into(),
            None,
            None,
            1,
            Default::default(),
        );

        assert_eq!("1:4MHSMLtBw+4q7Wke3ztBRVwtgt0=", id.unwrap());
    }
}