network: successfully implement NAT support for UDP. timeouts are not yet implemented.

This commit is contained in:
Alex Zenla 2024-02-10 12:00:15 +00:00
parent 360506bbdd
commit d2f86afb7c
No known key found for this signature in database
GPG Key ID: 067B238899B51269
3 changed files with 109 additions and 65 deletions

View File

@ -109,11 +109,11 @@ impl NetworkBackend {
.map_err(|_| anyhow!("failed to parse cidr: {}", self.network))?;
let addresses: Vec<IpCidr> = vec![address];
let kdev = AsyncRawSocket::bind(&self.interface)?;
let (sender, receiver) = channel::<Vec<u8>>(4);
let mut udev = ChannelDevice::new(1500, sender);
let (tx_sender, tx_receiver) = channel::<Vec<u8>>(4);
let mut udev = ChannelDevice::new(1500, tx_sender.clone());
let mac = MacAddr6::random();
let mac = smoltcp::wire::EthernetAddress(mac.to_array());
let nat = NatRouter::new(proxy, mac);
let nat = NatRouter::new(proxy, mac, tx_sender.clone());
let mac = HardwareAddress::Ethernet(mac);
let config = Config::new(mac);
let mut iface = Interface::new(config, &mut udev, Instant::now());
@ -124,7 +124,7 @@ impl NetworkBackend {
});
let sockets = SocketSet::new(vec![]);
Ok(NetworkStack {
tx: receiver,
tx: tx_receiver,
kdev,
udev,
interface: iface,

View File

@ -3,6 +3,7 @@
use anyhow::Result;
use async_trait::async_trait;
use etherparse::Ethernet2Slice;
use etherparse::IpNumber;
use etherparse::IpPayloadSlice;
use etherparse::Ipv4Slice;
@ -17,32 +18,31 @@ use smoltcp::wire::IpEndpoint;
use std::collections::hash_map::Entry;
use std::collections::HashMap;
use std::fmt::Display;
use tokio::sync::mpsc::Sender;
#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
pub enum NatKey {
Tcp {
client: IpEndpoint,
external: IpEndpoint,
},
pub enum NatKeyProtocol {
Tcp,
Udp,
Ping,
}
Udp {
client: IpEndpoint,
external: IpEndpoint,
},
Ping {
client: IpAddress,
external: IpAddress,
},
#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
pub struct NatKey {
pub protocol: NatKeyProtocol,
pub client_mac: EthernetAddress,
pub local_mac: EthernetAddress,
pub client_ip: IpEndpoint,
pub external_ip: IpEndpoint,
}
impl Display for NatKey {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
NatKey::Tcp { client, external } => write!(f, "TCP {client} -> {external}"),
NatKey::Udp { client, external } => write!(f, "UDP {client} -> {external}"),
NatKey::Ping { client, external } => write!(f, "Ping {client} -> {external}"),
}
write!(
f,
"{} -> {} {:?} {} -> {}",
self.client_mac, self.local_mac, self.protocol, self.client_ip, self.external_ip
)
}
}
@ -51,6 +51,11 @@ pub trait NatHandler: Send {
async fn receive(&self, packet: &[u8]) -> Result<()>;
}
#[async_trait]
pub trait NatHandlerFactory: Send {
async fn nat(&self, key: NatKey, sender: Sender<Vec<u8>>) -> Option<Box<dyn NatHandler>>;
}
pub struct NatTable {
inner: HashMap<NatKey, Box<dyn NatHandler>>,
}
@ -63,23 +68,24 @@ impl NatTable {
}
}
#[async_trait]
pub trait NatHandlerFactory: Send {
async fn nat(&self, key: NatKey) -> Option<Box<dyn NatHandler>>;
}
pub struct NatRouter {
_mac: EthernetAddress,
_local_mac: EthernetAddress,
factory: Box<dyn NatHandlerFactory>,
table: NatTable,
tx_sender: Sender<Vec<u8>>,
}
impl NatRouter {
pub fn new(factory: Box<dyn NatHandlerFactory>, mac: EthernetAddress) -> Self {
pub fn new(
factory: Box<dyn NatHandlerFactory>,
mac: EthernetAddress,
tx_sender: Sender<Vec<u8>>,
) -> Self {
Self {
_mac: mac,
_local_mac: mac,
factory,
table: NatTable::new(),
tx_sender,
}
}
@ -101,8 +107,9 @@ impl NatRouter {
match net {
NetSlice::Ipv4(ipv4) => {
self.process_ipv4(data, ipv4).await?;
self.process_ipv4(data, ether, ipv4).await?;
}
_ => {
return Ok(());
}
@ -111,18 +118,22 @@ impl NatRouter {
Ok(())
}
pub async fn process_ipv4<'a>(&mut self, data: &[u8], ipv4: &Ipv4Slice<'a>) -> Result<()> {
pub async fn process_ipv4<'a>(
&mut self,
data: &[u8],
ether: &Ethernet2Slice<'a>,
ipv4: &Ipv4Slice<'a>,
) -> Result<()> {
let source_addr = IpAddress::Ipv4(ipv4.header().source_addr().into());
let dest_addr = IpAddress::Ipv4(ipv4.header().destination_addr().into());
match ipv4.header().protocol() {
IpNumber::TCP => {
self.process_tcp(data, source_addr, dest_addr, ipv4.payload())
self.process_tcp(data, ether, source_addr, dest_addr, ipv4.payload())
.await?;
}
IpNumber::UDP => {
self.process_udp(data, source_addr, dest_addr, ipv4.payload())
self.process_udp(data, ether, source_addr, dest_addr, ipv4.payload())
.await?;
}
@ -135,6 +146,7 @@ impl NatRouter {
pub async fn process_tcp<'a>(
&mut self,
data: &'a [u8],
ether: &Ethernet2Slice<'a>,
source_addr: IpAddress,
dest_addr: IpAddress,
payload: &IpPayloadSlice<'a>,
@ -142,9 +154,12 @@ impl NatRouter {
let header = TcpHeaderSlice::from_slice(payload.payload)?;
let source = IpEndpoint::new(source_addr, header.source_port());
let dest = IpEndpoint::new(dest_addr, header.destination_port());
let key = NatKey::Tcp {
client: source,
external: dest,
let key = NatKey {
protocol: NatKeyProtocol::Tcp,
client_mac: EthernetAddress(ether.destination()),
local_mac: EthernetAddress(ether.source()),
client_ip: source,
external_ip: dest,
};
self.process_nat(data, key).await?;
Ok(())
@ -153,6 +168,7 @@ impl NatRouter {
pub async fn process_udp<'a>(
&mut self,
data: &'a [u8],
ether: &Ethernet2Slice<'a>,
source_addr: IpAddress,
dest_addr: IpAddress,
payload: &IpPayloadSlice<'a>,
@ -160,9 +176,12 @@ impl NatRouter {
let header = UdpHeaderSlice::from_slice(payload.payload)?;
let source = IpEndpoint::new(source_addr, header.source_port());
let dest = IpEndpoint::new(dest_addr, header.destination_port());
let key = NatKey::Udp {
client: source,
external: dest,
let key = NatKey {
protocol: NatKeyProtocol::Udp,
client_mac: EthernetAddress(ether.destination()),
local_mac: EthernetAddress(ether.source()),
client_ip: source,
external_ip: dest,
};
self.process_nat(data, key).await?;
Ok(())
@ -172,7 +191,7 @@ impl NatRouter {
let handler: Option<&mut Box<dyn NatHandler>> = match self.table.inner.entry(key) {
Entry::Occupied(entry) => Some(entry.into_mut()),
Entry::Vacant(entry) => {
if let Some(handler) = self.factory.nat(key).await {
if let Some(handler) = self.factory.nat(key, self.tx_sender.clone()).await {
Some(entry.insert(handler))
} else {
None

View File

@ -2,11 +2,11 @@ use std::net::{IpAddr, Ipv4Addr, SocketAddr};
use anyhow::{anyhow, Result};
use async_trait::async_trait;
use etherparse::{SlicedPacket, UdpSlice};
use etherparse::{PacketBuilder, SlicedPacket, UdpSlice};
use log::{debug, warn};
use smoltcp::{
phy::{Checksum, ChecksumCapabilities},
wire::{IpAddress, IpEndpoint},
wire::IpAddress,
};
use tokio::{
io::{AsyncReadExt, AsyncWriteExt},
@ -16,13 +16,13 @@ use tokio::{
use tokio::{sync::mpsc::Receiver, sync::mpsc::Sender};
use udp_stream::UdpStream;
use crate::nat::{NatHandler, NatHandlerFactory, NatKey};
use crate::nat::{NatHandler, NatHandlerFactory, NatKey, NatKeyProtocol};
pub struct ProxyNatHandlerFactory {}
struct ProxyUdpHandler {
external: IpEndpoint,
sender: Sender<Vec<u8>>,
key: NatKey,
rx_sender: Sender<Vec<u8>>,
}
impl ProxyNatHandlerFactory {
@ -33,18 +33,15 @@ impl ProxyNatHandlerFactory {
#[async_trait]
impl NatHandlerFactory for ProxyNatHandlerFactory {
async fn nat(&self, key: NatKey) -> Option<Box<dyn NatHandler>> {
async fn nat(&self, key: NatKey, sender: Sender<Vec<u8>>) -> Option<Box<dyn NatHandler>> {
debug!("creating proxy nat entry for key: {}", key);
match key {
NatKey::Udp {
client: _,
external,
} => {
let (sender, receiver) = channel::<Vec<u8>>(4);
let mut handler = ProxyUdpHandler { external, sender };
match key.protocol {
NatKeyProtocol::Udp => {
let (rx_sender, rx_receiver) = channel::<Vec<u8>>(4);
let mut handler = ProxyUdpHandler { key, rx_sender };
if let Err(error) = handler.spawn(receiver).await {
if let Err(error) = handler.spawn(rx_receiver, sender.clone()).await {
warn!("unable to spawn udp proxy handler: {}", error);
None
} else {
@ -60,7 +57,7 @@ impl NatHandlerFactory for ProxyNatHandlerFactory {
#[async_trait]
impl NatHandler for ProxyUdpHandler {
async fn receive(&self, data: &[u8]) -> Result<()> {
self.sender.try_send(data.to_vec())?;
self.rx_sender.try_send(data.to_vec())?;
Ok(())
}
}
@ -72,25 +69,36 @@ enum ProxySelect {
}
impl ProxyUdpHandler {
async fn spawn(&mut self, receiver: Receiver<Vec<u8>>) -> Result<()> {
let external_addr = match self.external.addr {
async fn spawn(
&mut self,
rx_receiver: Receiver<Vec<u8>>,
tx_sender: Sender<Vec<u8>>,
) -> Result<()> {
let external_addr = match self.key.external_ip.addr {
IpAddress::Ipv4(addr) => SocketAddr::new(
IpAddr::V4(Ipv4Addr::new(addr.0[0], addr.0[1], addr.0[2], addr.0[3])),
self.external.port,
self.key.external_ip.port,
),
IpAddress::Ipv6(_) => return Err(anyhow!("IPv6 unsupported")),
};
let socket = UdpStream::connect(external_addr).await?;
let key = self.key;
tokio::spawn(async move {
if let Err(error) = ProxyUdpHandler::process(socket, receiver).await {
if let Err(error) = ProxyUdpHandler::process(key, socket, rx_receiver, tx_sender).await
{
warn!("processing of udp proxy failed: {}", error);
}
});
Ok(())
}
async fn process(mut socket: UdpStream, mut receiver: Receiver<Vec<u8>>) -> Result<()> {
async fn process(
key: NatKey,
mut socket: UdpStream,
mut rx_receiver: Receiver<Vec<u8>>,
tx_sender: Sender<Vec<u8>>,
) -> Result<()> {
let mut checksum = ChecksumCapabilities::ignored();
checksum.udp = Checksum::Tx;
checksum.ipv4 = Checksum::Tx;
@ -100,7 +108,7 @@ impl ProxyUdpHandler {
loop {
let selection = select! {
x = receiver.recv() => if let Some(data) = x {
x = rx_receiver.recv() => if let Some(data) = x {
ProxySelect::Internal(data)
} else {
ProxySelect::Closed
@ -111,7 +119,24 @@ impl ProxyUdpHandler {
match selection {
ProxySelect::External(size) => {
let data = &external_buffer[0..size];
debug!("UDP from external: {:?}", data);
let packet = PacketBuilder::ethernet2(key.local_mac.0, key.client_mac.0);
let packet = match (key.external_ip.addr, key.client_ip.addr) {
(IpAddress::Ipv4(external_addr), IpAddress::Ipv4(client_addr)) => {
packet.ipv4(external_addr.0, client_addr.0, 20)
}
(IpAddress::Ipv6(external_addr), IpAddress::Ipv6(client_addr)) => {
packet.ipv6(external_addr.0, client_addr.0, 20)
}
_ => {
return Err(anyhow!("IP endpoint mismatch"));
}
};
let packet = packet.udp(key.external_ip.port, key.client_ip.port);
let mut buffer: Vec<u8> = Vec::new();
packet.write(&mut buffer, data)?;
if let Err(error) = tx_sender.try_send(buffer) {
debug!("failed to transmit udp packet: {}", error);
}
}
ProxySelect::Internal(data) => {
debug!("udp socket to handle data: {:?}", data);