sdlan-lib-rs/src/network/tuntap.rs

use std::sync::atomic::Ordering;

use bytes::{Bytes, BytesMut};
use dashmap::DashMap;
use once_cell::sync::OnceCell;
use sdlan_sn_rs::{
    config::SDLAN_DEFAULT_TTL,
    utils::{get_current_timestamp, ip_to_string, Mac, Result},
};

use tracing::{debug, warn};

use tracing::error;

use crate::{
    network::{form_ethernet_packet, send_packet_to_net, Node, RouteInfo},
    pb::{encode_to_udp_message, SdlData},
    tcp::PacketType,
    utils::mac_to_string,
};

use super::get_edge;

pub const MAX_WAIT_PACKETS: usize = 100;

const DEFAULT_DNS_SERVER: u32 = (223 << 24) + (5 << 16) + (5 << 8) + 5; // ali dns

pub trait TunTapPacketHandler {
    async fn handle_packet_from_net(&self, data: &[u8]) -> std::io::Result<()>;
    async fn handle_packet_from_device(&self, data: BytesMut) -> std::io::Result<()>;
}

pub fn set_route_from_net(routes: Vec<RouteInfo>) -> Result<()> {
    let eee = get_edge();
    eee.route_table.clear_and_add_routes(routes)?;
    eee.route_table.apply_system(eee.device.get_if_idx());
    Ok(())
}

/*
static ARP_WAIT_LIST: OnceCell<ArpWaitList> = OnceCell::new();

pub fn init_arp_wait_list() {
    let waitlist = ArpWaitList {
        content: DashMap::new(),
    };
    ARP_WAIT_LIST.set(waitlist).unwrap();
}

#[derive(Debug)]
pub struct ArpWaitInfo {
    timestamp: u64,
    // origin data is from the tun or tap device
    origin_data: BytesMut,
}

#[derive(Debug)]
pub struct ArpWaitList {
    content: DashMap<u32, Vec<ArpWaitInfo>>,
}

impl ArpWaitList {
    fn add_to_wait_list(&self, ip: u32, origin_data_with_zeroed_layer2: BytesMut) {
        let mut entry = self.content.entry(ip).or_insert(vec![]);
        if entry.len() < MAX_WAIT_PACKETS {
            entry.push(ArpWaitInfo {
                timestamp: get_current_timestamp(),
                origin_data: origin_data_with_zeroed_layer2,
            })
        }
    }

    async fn arp_arrived(&self, ip: u32, mac: Mac) {
        debug!(
            "arp for {} arrived: {}",
            ip_to_string(&ip),
            mac_to_string(&mac)
        );
        let Some(items) = self.content.remove(&ip) else {
            return;
        };
        let edge = get_edge();
        // just remove the items
        if !edge.is_authorized() {
            return;
        }

        // let encrypt_key = edge.get_encrypt_key();
        let network_id = edge.network_id.load(Ordering::Relaxed);

        let src_mac = edge.device_config.get_mac();
        let now = get_current_timestamp();
        for item in items.1 {
            if (now - item.timestamp) > 5 {
                continue;
            }
            let packet = form_ethernet_packet(src_mac, mac, item.origin_data);

            let pkt_size = packet.len();

            let Ok(encrypted) = edge.encryptor.load().encrypt(&packet) else {
            // let Ok(encrypted) = edge.encryptor.read().unwrap().encrypt(&packet) else {
            // let Ok(encrypted) = aes_encrypt(&encrypt_key, &packet) else {
                error!("failed to encrypt packet request");
                return;
            };
            let data_bytes = Bytes::from(encrypted);
            let data = SdlData {
                is_p2p: true,
                network_id,
                ttl: SDLAN_DEFAULT_TTL as u32,
                src_mac: Vec::from(src_mac),
                dst_mac: Vec::from(mac),
                data: data_bytes,
                identity_id: edge.identity_id.load(),
                session_token: edge.session_token.get(),
            };
            let msg = encode_to_udp_message(Some(data), PacketType::Data as u8).unwrap();
            send_packet_to_net(edge, mac, &msg, pkt_size as u64).await;
        }
    }
}

pub fn add_to_arp_wait_list(ip: u32, origin_data_with_zeroed_layer2: BytesMut) {
    let waitlist = ARP_WAIT_LIST
        .get()
        .expect("ARP_WAIT_LIST has not been inited");

    waitlist.add_to_wait_list(ip, origin_data_with_zeroed_layer2);
}

pub async fn arp_arrived(ip: u32, mac: Mac) {
    let waitlist = ARP_WAIT_LIST
        .get()
        .expect("ARP_WAIT_LIST has not been inited");

    waitlist.arp_arrived(ip, mac).await;
}
*/

pub fn get_dns_gateway(edge: &Node, payload: &[u8]) -> Option<String> {
    let dns_packet = match simple_dns::Packet::parse(payload) {
        Err(e) => {
            error!("failed to parse dns packet: {}", e);
            return None;
        }
        Ok(p) => p,
    };

    let mut target_dns: &str = "";
    if !dns_packet.has_flags(simple_dns::PacketFlag::RESPONSE) && !dns_packet.questions.is_empty() {
        let question = &dns_packet.questions[0];
        let domain = question.qname.to_string();

        let self_domain = &edge.network_domain.load();
        if self_domain.is_empty() {
            return None;
        }

        if domain.ends_with(self_domain.as_str()) {
            debug!("got dns request for domain {}, which ends with our network domain {}, should send to dns server", domain, self_domain);
            return Some(domain);
        }
    }
    return None;
}

pub async fn parse_dns_payload(
    edge: &Node,
    layer7: &[u8],
    layer3: &[u8],
    source_ip: u32,
    source_port: u16,
) {
    match simple_dns::Packet::parse(layer7) {
        Ok(mut dns) => {
            if !dns.has_flags(simple_dns::PacketFlag::RESPONSE) && !dns.questions.is_empty() {
                let question = &dns.questions[0];
                let qname = question.qname.to_string();
                if qname.ends_with(edge.network_domain.load().as_str()) {
                    warn!(
                        "question 15353 for {} from {}:{} with transaction_id = {}",
                        qname,
                        ip_to_string(&source_ip),
                        source_port,
                        dns.id()
                    );
                    // should send to our socket
                    if let Err(e) = edge
                        .udp_sock_for_dns
                        .send_to(layer3, format!("{}:15353", edge.server_ip))
                        .await
                    {
                        error!("failed to send request to 15353: {}", e);
                    }
                } else {
                    let origin_transaction_id = dns.id();
                    let transaction_id = edge.dns_matcher.generate_transaction_id(
                        source_ip,
                        source_port,
                        origin_transaction_id,
                    );
                    dns.set_id(transaction_id);
                    warn!(
                        "question 223.5.5.5 for {} from {}:{} with transaction_id = {}",
                        qname,
                        ip_to_string(&source_ip),
                        source_port,
                        dns.id()
                    );
                    if let Ok(res) = dns.build_bytes_vec() {
                        if let Err(e) = edge
                            .udp_sock_for_global_dns
                            .send_to(&res, "223.5.5.5:53")
                            .await
                        {
                            error!("failed to query for global dns: {}", e);
                        }
                    }
                    // edge.udp_sock_for_global_dns.send_to()
                }
            }
        }
        Err(e) => {
            error!("failed to parse dns packet");
        }
    }
}