Files
Easytier_lkddi/easytier/src/instance/dns_server/server_instance.rs
2025-10-18 12:48:04 +08:00

568 lines
18 KiB
Rust

// single-instance server in one machine, every easytier instance that has ip address and tun device will try to create a server instance.
// magic dns client will connect to this server to update the dns records.
// magic dns server will add the dns server ip address to the tun device, and forward the dns request to the dns server
// magic dns client will establish a long live tcp connection to the magic dns server, and when the server stops or crashes,
// all the clients will exit and let the easytier instance to launch a new server instance.
use super::{
config::{GeneralConfigBuilder, RunConfigBuilder},
server::Server,
system_config::{OSConfig, SystemConfig},
MAGIC_DNS_INSTANCE_ADDR,
};
use crate::{
common::{
ifcfg::{IfConfiger, IfConfiguerTrait},
PeerId,
},
instance::dns_server::{
config::{Record, RecordBuilder, RecordType},
server::build_authority,
},
peers::{peer_manager::PeerManager, NicPacketFilter},
proto::{
api::instance::Route,
common::{TunnelInfo, Void},
magic_dns::{
dns_record::{self},
DnsRecord, DnsRecordA, DnsRecordList, GetDnsRecordResponse, HandshakeRequest,
HandshakeResponse, MagicDnsServerRpc, MagicDnsServerRpcServer, UpdateDnsRecordRequest,
},
rpc_impl::standalone::{RpcServerHook, StandAloneServer},
rpc_types::controller::{BaseController, Controller},
},
tunnel::{packet_def::ZCPacket, tcp::TcpTunnelListener},
};
use anyhow::Context;
use cidr::Ipv4Inet;
use dashmap::DashMap;
use hickory_proto::rr::LowerName;
use hickory_proto::serialize::binary::{BinDecodable, BinEncoder};
use hickory_server::authority::{MessageRequest, MessageResponse};
use hickory_server::server::{Request, RequestHandler, ResponseHandler, ResponseInfo};
use multimap::MultiMap;
use pnet::packet::icmp::{IcmpTypes, MutableIcmpPacket};
use pnet::packet::ipv4::Ipv4Packet;
use pnet::packet::udp::UdpPacket;
use pnet::packet::{
icmp,
ip::IpNextHeaderProtocols,
ipv4::{self, MutableIpv4Packet},
udp::{self, MutableUdpPacket},
MutablePacket, Packet,
};
use std::net::{SocketAddr, SocketAddrV4};
use std::sync::Mutex;
use std::{collections::BTreeMap, io, net::Ipv4Addr, str::FromStr, sync::Arc, time::Duration};
static NIC_PIPELINE_NAME: &str = "magic_dns_server";
pub(super) struct MagicDnsServerInstanceData {
dns_server: Server,
tun_dev: Option<String>,
tun_ip: Ipv4Addr,
fake_ip: Ipv4Addr,
my_peer_id: PeerId,
// zone -> (tunnel remote addr -> route)
route_infos: DashMap<String, MultiMap<url::Url, Route>>,
system_config: Option<Box<dyn SystemConfig>>,
}
impl MagicDnsServerInstanceData {
pub async fn update_dns_records<'a, T: Iterator<Item = &'a Route>>(
&self,
routes: T,
zone: &str,
) -> Result<(), anyhow::Error> {
let mut records: Vec<Record> = vec![];
for route in routes {
if route.hostname.is_empty() {
continue;
}
let Some(ipv4_addr) = route.ipv4_addr.unwrap_or_default().address else {
continue;
};
let record = RecordBuilder::default()
.rr_type(RecordType::A)
.name(format!("{}.{}", route.hostname, zone))
.value(ipv4_addr.to_string())
.ttl(Duration::from_secs(1))
.build()?;
// check record name valid for dns
if let Err(e) = record.name() {
tracing::error!("Invalid subdomain label: {}", e);
continue;
}
records.push(record);
}
let soa_record = RecordBuilder::default()
.rr_type(RecordType::SOA)
.name(zone.to_string())
.value(format!(
"ns.{} hostmaster.{} 2023101001 7200 3600 1209600 86400",
zone, zone
))
.ttl(Duration::from_secs(60))
.build()?;
records.push(soa_record);
let authority = build_authority(zone, &records)?;
self.dns_server
.upsert(
LowerName::from_str(zone)
.with_context(|| "Invalid zone name, expect format like \"et.net.\"")?,
Arc::new(authority),
)
.await;
tracing::debug!("Updated DNS records for zone {}: {:?}", zone, records);
Ok(())
}
pub async fn update(&self) {
for item in self.route_infos.iter() {
let zone = item.key();
let route_iter = item.value().flat_iter().map(|x| x.1);
if let Err(e) = self.update_dns_records(route_iter, zone).await {
tracing::error!("Failed to update DNS records for zone {}: {:?}", zone, e);
}
}
}
fn do_system_config(&self, zone: &str) -> Result<(), anyhow::Error> {
if let Some(c) = &self.system_config {
c.set_dns(&OSConfig {
nameservers: vec![self.fake_ip.to_string()],
search_domains: vec![zone.to_string()],
match_domains: vec![zone.to_string()],
})?;
}
Ok(())
}
}
#[async_trait::async_trait]
impl MagicDnsServerRpc for MagicDnsServerInstanceData {
type Controller = BaseController;
async fn handshake(
&self,
_ctrl: Self::Controller,
_input: HandshakeRequest,
) -> crate::proto::rpc_types::error::Result<HandshakeResponse> {
Ok(Default::default())
}
async fn heartbeat(
&self,
_ctrl: Self::Controller,
_input: Void,
) -> crate::proto::rpc_types::error::Result<Void> {
Ok(Default::default())
}
async fn update_dns_record(
&self,
ctrl: Self::Controller,
input: UpdateDnsRecordRequest,
) -> crate::proto::rpc_types::error::Result<Void> {
let Some(tunnel_info) = ctrl.get_tunnel_info() else {
return Err(anyhow::anyhow!("No tunnel info").into());
};
let Some(remote_addr) = &tunnel_info.remote_addr else {
return Err(anyhow::anyhow!("No remote addr").into());
};
let zone = input.zone.clone();
self.route_infos
.entry(zone.clone())
.or_default()
.insert_many(remote_addr.clone().into(), input.routes);
self.update().await;
Ok(Default::default())
}
async fn get_dns_record(
&self,
_ctrl: Self::Controller,
_input: Void,
) -> crate::proto::rpc_types::error::Result<GetDnsRecordResponse> {
let mut ret = BTreeMap::new();
for item in self.route_infos.iter() {
let zone = item.key();
let routes = item.value();
let mut dns_records = DnsRecordList::default();
for route in routes.iter().map(|x| x.1) {
dns_records.records.push(DnsRecord {
record: Some(dns_record::Record::A(DnsRecordA {
name: format!("{}.{}", route.hostname, zone),
value: route.ipv4_addr.unwrap_or_default().address,
ttl: 1,
})),
});
}
ret.insert(zone.clone(), dns_records);
}
Ok(GetDnsRecordResponse { records: ret })
}
}
// This should only be used for UDP response.
// For other protocols, the variable `max_size` in `send_response` should be u16::MAX.
#[derive(Clone)]
struct ResponseWrapper {
response: Arc<Mutex<Vec<u8>>>,
}
trait RecordIter<'a>: Iterator<Item = &'a hickory_proto::rr::Record> + Send + 'a {}
impl<'a, T> RecordIter<'a> for T where T: Iterator<Item = &'a hickory_proto::rr::Record> + Send + 'a {}
#[async_trait::async_trait]
impl ResponseHandler for ResponseWrapper {
async fn send_response<'a>(
&mut self,
response: MessageResponse<
'_,
'a,
impl RecordIter<'a>,
impl RecordIter<'a>,
impl RecordIter<'a>,
impl RecordIter<'a>,
>,
) -> io::Result<ResponseInfo> {
let mut buffer = self
.response
.lock()
.map_err(|_| io::Error::other("lock poisoned"))?;
let mut encoder = BinEncoder::new(&mut buffer);
// `max_size` should be u16::MAX for protocol other than UDP.
let max_size = if let Some(edns) = response.get_edns() {
edns.max_payload()
} else {
hickory_proto::udp::MAX_RECEIVE_BUFFER_SIZE as u16
};
encoder.set_max_size(max_size);
response
.destructive_emit(&mut encoder)
.map_err(io::Error::other)
}
}
impl MagicDnsServerInstanceData {
/// Replace content of incoming UDP DNS request and ICMP echo request packet with reply data,
/// and swap source and destination IP addresses to send it back.
async fn handle_ip_packet(&self, zc_packet: &mut ZCPacket) -> Option<()> {
let (ip_header_length, ip_protocol, src_ip, dst_ip) = {
let ip_packet = Ipv4Packet::new(zc_packet.payload())?;
if ip_packet.get_version() != 4 {
return None;
}
(
ip_packet.get_header_length() as usize * 4,
ip_packet.get_next_level_protocol(),
ip_packet.get_source(),
ip_packet.get_destination(),
)
};
if dst_ip != self.fake_ip {
return None;
}
match ip_protocol {
IpNextHeaderProtocols::Udp => {
self.handle_udp_packet(zc_packet, ip_header_length, src_ip, dst_ip)
.await?;
}
IpNextHeaderProtocols::Icmp => {
self.handle_icmp_packet(zc_packet, ip_header_length)?;
}
_ => {
return None;
}
}
let mut ip_packet = MutableIpv4Packet::new(zc_packet.mut_payload())?;
ip_packet.set_source(dst_ip);
ip_packet.set_destination(src_ip);
ip_packet.set_checksum(ipv4::checksum(&ip_packet.to_immutable()));
zc_packet.mut_peer_manager_header().unwrap().to_peer_id = self.my_peer_id.into();
Some(())
}
/// Extract the DNS request message and send it to the hickory-dns server instance.
/// Replace the content of the UDP packet with the response message.
async fn handle_udp_packet(
&self,
zc_packet: &mut ZCPacket,
ip_header_length: usize,
src_ip: Ipv4Addr,
dst_ip: Ipv4Addr,
) -> Option<()> {
let (src_port, dst_port, request, request_length) = {
let udp_packet = UdpPacket::new(&zc_packet.payload()[ip_header_length..])?;
let src_port = udp_packet.get_source();
let dst_port = udp_packet.get_destination();
// Remove this to support any UDP port
if dst_port != 53 {
return None;
}
let request_payload = udp_packet.payload();
(
src_port,
dst_port,
Request::new(
MessageRequest::from_bytes(request_payload).ok()?,
SocketAddr::from(SocketAddrV4::new(src_ip, src_port)),
hickory_proto::xfer::Protocol::Udp,
),
request_payload.len(),
)
};
let response_payload = {
let response_payload_arc = Arc::new(Mutex::new(Vec::with_capacity(512)));
self.dns_server
.read_catalog()
.await
.handle_request(
&request,
ResponseWrapper {
response: response_payload_arc.clone(),
},
)
.await;
Arc::into_inner(response_payload_arc)?.into_inner().ok()?
};
let response_length = response_payload.len();
let delta_length = response_length as isize - request_length as isize;
let inner_length = (zc_packet.buf_len() as isize + delta_length) as usize;
if zc_packet.mut_inner().capacity() < inner_length {
let header_length = inner_length - response_length;
zc_packet.mut_inner().truncate(header_length);
}
zc_packet.mut_inner().resize(inner_length, 0);
let mut ip_packet = MutableIpv4Packet::new(zc_packet.mut_payload())?;
let ip_length = (ip_packet.get_total_length() as isize + delta_length) as u16;
ip_packet.set_total_length(ip_length);
let mut udp_packet = MutableUdpPacket::new(ip_packet.payload_mut())?;
let udp_length = (udp_packet.get_length() as isize + delta_length) as u16;
udp_packet.set_length(udp_length);
udp_packet.set_source(dst_port);
udp_packet.set_destination(src_port);
udp_packet.payload_mut().copy_from_slice(&response_payload);
udp_packet.set_checksum(udp::ipv4_checksum(
&udp_packet.to_immutable(),
&dst_ip,
&src_ip,
));
Some(())
}
fn handle_icmp_packet(&self, zc_packet: &mut ZCPacket, ip_header_length: usize) -> Option<()> {
let mut icmp_packet =
MutableIcmpPacket::new(&mut zc_packet.mut_payload()[ip_header_length..])?;
if icmp_packet.get_icmp_type() != IcmpTypes::EchoRequest {
return None;
}
icmp_packet.set_icmp_type(IcmpTypes::EchoReply);
icmp_packet.set_checksum(icmp::checksum(&icmp_packet.to_immutable()));
Some(())
}
}
#[async_trait::async_trait]
impl NicPacketFilter for MagicDnsServerInstanceData {
async fn try_process_packet_from_nic(&self, zc_packet: &mut ZCPacket) -> bool {
self.handle_ip_packet(zc_packet).await.is_some()
}
fn id(&self) -> String {
NIC_PIPELINE_NAME.to_string()
}
}
#[async_trait::async_trait]
impl RpcServerHook for MagicDnsServerInstanceData {
async fn on_new_client(
&self,
tunnel_info: Option<TunnelInfo>,
) -> Result<Option<TunnelInfo>, anyhow::Error> {
tracing::info!(?tunnel_info, "New client connected");
Ok(tunnel_info)
}
async fn on_client_disconnected(&self, tunnel_info: Option<TunnelInfo>) {
tracing::info!(?tunnel_info, "Client disconnected");
let Some(tunnel_info) = tunnel_info else {
return;
};
let Some(remote_addr) = tunnel_info.remote_addr else {
return;
};
let remote_addr = remote_addr.into();
for mut item in self.route_infos.iter_mut() {
item.value_mut().remove(&remote_addr);
}
self.route_infos.retain(|_, v| !v.is_empty());
self.route_infos.shrink_to_fit();
self.update().await;
}
}
pub struct MagicDnsServerInstance {
rpc_server: StandAloneServer<TcpTunnelListener>,
pub(super) data: Arc<MagicDnsServerInstanceData>,
peer_mgr: Arc<PeerManager>,
tun_inet: Ipv4Inet,
}
fn get_system_config(
_tun_name: Option<&str>,
) -> Result<Option<Box<dyn SystemConfig>>, anyhow::Error> {
#[cfg(target_os = "windows")]
{
use super::system_config::windows::WindowsDNSManager;
let tun_name = _tun_name.ok_or_else(|| anyhow::anyhow!("No tun name"))?;
return Ok(Some(Box::new(WindowsDNSManager::new(tun_name)?)));
}
#[cfg(target_os = "macos")]
{
use super::system_config::darwin::DarwinConfigurator;
return Ok(Some(Box::new(DarwinConfigurator::new())));
}
#[allow(unreachable_code)]
Ok(None)
}
impl MagicDnsServerInstance {
pub async fn new(
peer_mgr: Arc<PeerManager>,
tun_dev: Option<String>,
tun_inet: Ipv4Inet,
fake_ip: Ipv4Addr,
) -> Result<Self, anyhow::Error> {
let tcp_listener = TcpTunnelListener::new(MAGIC_DNS_INSTANCE_ADDR.parse()?);
let mut rpc_server = StandAloneServer::new(tcp_listener);
rpc_server.serve().await?;
let dns_config = RunConfigBuilder::default()
.general(GeneralConfigBuilder::default().build()?)
.excluded_forward_nameservers(vec![fake_ip.into()])
.build()?;
let mut dns_server = Server::new(dns_config);
dns_server.run().await?;
if !tun_inet.contains(&fake_ip) && tun_dev.is_some() {
let cost = if cfg!(target_os = "windows") {
Some(4)
} else {
None
};
let ifcfg = IfConfiger {};
ifcfg
.add_ipv4_route(tun_dev.as_ref().unwrap(), fake_ip, 32, cost)
.await?;
}
let data = Arc::new(MagicDnsServerInstanceData {
dns_server,
tun_dev: tun_dev.clone(),
tun_ip: tun_inet.address(),
fake_ip,
my_peer_id: peer_mgr.my_peer_id(),
route_infos: DashMap::new(),
system_config: get_system_config(tun_dev.as_deref())?,
});
rpc_server
.registry()
.register(MagicDnsServerRpcServer::new(data.clone()), "");
rpc_server.set_hook(data.clone());
peer_mgr
.add_nic_packet_process_pipeline(Box::new(data.clone()))
.await;
// Use configured tld_dns_zone or fall back to DEFAULT_ET_DNS_ZONE if empty
let flags = peer_mgr.get_global_ctx().config.get_flags();
let tld_dns_zone_clone = flags.tld_dns_zone.clone();
let data_clone = data.clone();
tokio::task::spawn_blocking(move || data_clone.do_system_config(&tld_dns_zone_clone))
.await
.context("Failed to configure system")??;
Ok(Self {
rpc_server,
data,
peer_mgr,
tun_inet,
})
}
pub async fn clean_env(&self) {
if let Some(configer) = &self.data.system_config {
let ret = configer.close();
if let Err(e) = ret {
tracing::error!("Failed to close system config: {:?}", e);
}
}
if !self.tun_inet.contains(&self.data.fake_ip) && self.data.tun_dev.is_some() {
let ifcfg = IfConfiger {};
let _ = ifcfg
.remove_ipv4_route(self.data.tun_dev.as_ref().unwrap(), self.data.fake_ip, 32)
.await;
}
let _ = self
.peer_mgr
.remove_nic_packet_process_pipeline(NIC_PIPELINE_NAME.to_string())
.await;
}
}
impl Drop for MagicDnsServerInstance {
fn drop(&mut self) {
println!("MagicDnsServerInstance dropped");
}
}