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network: implement NAT table reclaim

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This commit is contained in:
Alex Zenla
2024-02-10 14:02:54 +00:00
parent 8ee93c5752
commit d2136b5d8c
4 changed files with 98 additions and 36 deletions
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4
network/src/backend.rs
View File

@ -24,6 +24,7 @@ pub struct NetworkBackend {
enum NetworkStackSelect<'a> {
Receive(&'a [u8]),
Send(Option<Vec<u8>>),
Reclaim,
}
struct NetworkStack<'a> {
@ -40,6 +41,7 @@ impl NetworkStack<'_> {
let what = select! {
x = self.tx.recv() => NetworkStackSelect::Send(x),
x = self.kdev.read(receive_buffer) => NetworkStackSelect::Receive(&receive_buffer[0..x?]),
_ = self.router.process_reclaim() => NetworkStackSelect::Reclaim,
};
match what {
@ -59,6 +61,8 @@ impl NetworkStack<'_> {
self.interface
.poll(timestamp, &mut self.udev, &mut self.sockets);
}
NetworkStackSelect::Reclaim => {}
}
Ok(())

70
network/src/nat.rs
View File

@ -1,23 +1,24 @@
// Referenced https://github.com/vi/wgslirpy/blob/master/crates/libwgslirpy/src/router.rs as a very interesting way to implement NAT.
// hypha will heavily change how the original code functions however. NatKey was a very useful example of what we need to store in a NAT map.
use anyhow::Result;
use async_trait::async_trait;
use etherparse::Ethernet2Slice;
use etherparse::IpNumber;
use etherparse::IpPayloadSlice;
use etherparse::Ipv4Slice;
use etherparse::Ipv6Slice;
use etherparse::LinkSlice;
use etherparse::NetSlice;
use etherparse::SlicedPacket;
use etherparse::TcpHeaderSlice;
use etherparse::UdpHeaderSlice;
use log::debug;
use smoltcp::wire::EthernetAddress;
use smoltcp::wire::IpAddress;
use smoltcp::wire::IpEndpoint;
use std::collections::hash_map::Entry;
use std::collections::HashMap;
use std::fmt::Display;
use tokio::sync::mpsc::channel;
use tokio::sync::mpsc::Receiver;
use tokio::sync::mpsc::Sender;
#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
@ -52,7 +53,12 @@ pub trait NatHandler: Send {
#[async_trait]
pub trait NatHandlerFactory: Send {
async fn nat(&self, key: NatKey, sender: Sender<Vec<u8>>) -> Option<Box<dyn NatHandler>>;
async fn nat(
&self,
key: NatKey,
tx_sender: Sender<Vec<u8>>,
reclaim_sender: Sender<NatKey>,
) -> Option<Box<dyn NatHandler>>;
}
pub struct NatTable {
@ -72,6 +78,8 @@ pub struct NatRouter {
factory: Box<dyn NatHandlerFactory>,
table: NatTable,
tx_sender: Sender<Vec<u8>>,
reclaim_sender: Sender<NatKey>,
reclaim_receiver: Receiver<NatKey>,
}
impl NatRouter {
@ -80,14 +88,27 @@ impl NatRouter {
mac: EthernetAddress,
tx_sender: Sender<Vec<u8>>,
) -> Self {
let (reclaim_sender, reclaim_receiver) = channel(4);
Self {
_local_mac: mac,
factory,
table: NatTable::new(),
tx_sender,
reclaim_sender,
reclaim_receiver,
}
}
pub async fn process_reclaim(&mut self) -> Result<Option<NatKey>> {
Ok(if let Some(key) = self.reclaim_receiver.recv().await {
self.table.inner.remove(&key);
debug!("reclaimed nat key: {}", key);
Some(key)
} else {
None
})
}
pub async fn process(&mut self, data: &[u8]) -> Result<()> {
let packet = SlicedPacket::from_ethernet(data)?;
let Some(ref link) = packet.link else {
@ -105,13 +126,8 @@ impl NatRouter {
};
match net {
NetSlice::Ipv4(ipv4) => {
self.process_ipv4(data, ether, ipv4).await?;
}
_ => {
return Ok(());
}
NetSlice::Ipv4(ipv4) => self.process_ipv4(data, ether, ipv4).await?,
NetSlice::Ipv6(ipv6) => self.process_ipv6(data, ether, ipv6).await?,
}
Ok(())
@ -142,6 +158,31 @@ impl NatRouter {
Ok(())
}
pub async fn process_ipv6<'a>(
&mut self,
data: &[u8],
ether: &Ethernet2Slice<'a>,
ipv6: &Ipv6Slice<'a>,
) -> Result<()> {
let source_addr = IpAddress::Ipv6(ipv6.header().source_addr().into());
let dest_addr = IpAddress::Ipv6(ipv6.header().destination_addr().into());
match ipv6.header().next_header() {
IpNumber::TCP => {
self.process_tcp(data, ether, source_addr, dest_addr, ipv6.payload())
.await?;
}
IpNumber::UDP => {
self.process_udp(data, ether, source_addr, dest_addr, ipv6.payload())
.await?;
}
_ => {}
}
Ok(())
}
pub async fn process_tcp<'a>(
&mut self,
data: &'a [u8],
@ -190,7 +231,11 @@ 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, self.tx_sender.clone()).await {
if let Some(handler) = self
.factory
.nat(key, self.tx_sender.clone(), self.reclaim_sender.clone())
.await
{
Some(entry.insert(handler))
} else {
None
@ -201,7 +246,6 @@ impl NatRouter {
if let Some(handler) = handler {
handler.receive(data).await?;
}
Ok(())
}
}

15
network/src/proxynat/mod.rs
View File

@ -1,5 +1,3 @@
mod udp;
use async_trait::async_trait;
use log::{debug, warn};
@ -11,6 +9,8 @@ use crate::proxynat::udp::ProxyUdpHandler;
use crate::nat::{NatHandler, NatHandlerFactory, NatKey, NatKeyProtocol};
mod udp;
pub struct ProxyNatHandlerFactory {}
impl ProxyNatHandlerFactory {
@ -21,7 +21,12 @@ impl ProxyNatHandlerFactory {
#[async_trait]
impl NatHandlerFactory for ProxyNatHandlerFactory {
async fn nat(&self, key: NatKey, sender: Sender<Vec<u8>>) -> Option<Box<dyn NatHandler>> {
async fn nat(
&self,
key: NatKey,
tx_sender: Sender<Vec<u8>>,
reclaim_sender: Sender<NatKey>,
) -> Option<Box<dyn NatHandler>> {
debug!("creating proxy nat entry for key: {}", key);
match key.protocol {
@ -29,7 +34,7 @@ impl NatHandlerFactory for ProxyNatHandlerFactory {
let (rx_sender, rx_receiver) = channel::<Vec<u8>>(4);
let mut handler = ProxyUdpHandler::new(key, rx_sender);
if let Err(error) = handler.spawn(rx_receiver, sender.clone()).await {
if let Err(error) = handler.spawn(rx_receiver, tx_sender, reclaim_sender).await {
warn!("unable to spawn udp proxy handler: {}", error);
None
} else {
@ -45,5 +50,5 @@ impl NatHandlerFactory for ProxyNatHandlerFactory {
pub enum ProxyNatSelect {
External(usize),
Internal(Vec<u8>),
Closed,
Close,
}

45
network/src/proxynat/udp.rs
View File

@ -1,13 +1,13 @@
use std::net::{IpAddr, Ipv4Addr, SocketAddr};
use std::{
net::{IpAddr, SocketAddr},
time::Duration,
};
use anyhow::{anyhow, Result};
use async_trait::async_trait;
use etherparse::{PacketBuilder, SlicedPacket, UdpSlice};
use log::{debug, warn};
use smoltcp::{
phy::{Checksum, ChecksumCapabilities},
wire::IpAddress,
};
use smoltcp::wire::IpAddress;
use tokio::{
io::{AsyncReadExt, AsyncWriteExt},
select,
@ -19,6 +19,8 @@ use crate::nat::{NatHandler, NatKey};
use super::ProxyNatSelect;
const UDP_TIMEOUT_SECS: u64 = 60;
pub struct ProxyUdpHandler {
key: NatKey,
rx_sender: Sender<Vec<u8>>,
@ -41,19 +43,22 @@ impl ProxyUdpHandler {
&mut self,
rx_receiver: Receiver<Vec<u8>>,
tx_sender: Sender<Vec<u8>>,
reclaim_sender: Sender<NatKey>,
) -> 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.key.external_ip.port,
),
IpAddress::Ipv6(_) => return Err(anyhow!("IPv6 unsupported")),
IpAddress::Ipv4(addr) => {
SocketAddr::new(IpAddr::V4(addr.0.into()), self.key.external_ip.port)
}
IpAddress::Ipv6(addr) => {
SocketAddr::new(IpAddr::V6(addr.0.into()), self.key.external_ip.port)
}
};
let socket = UdpStream::connect(external_addr).await?;
let key = self.key;
tokio::spawn(async move {
if let Err(error) = ProxyUdpHandler::process(key, socket, rx_receiver, tx_sender).await
if let Err(error) =
ProxyUdpHandler::process(key, socket, rx_receiver, tx_sender, reclaim_sender).await
{
warn!("processing of udp proxy failed: {}", error);
}
@ -66,22 +71,20 @@ impl ProxyUdpHandler {
mut socket: UdpStream,
mut rx_receiver: Receiver<Vec<u8>>,
tx_sender: Sender<Vec<u8>>,
reclaim_sender: Sender<NatKey>,
) -> Result<()> {
let mut checksum = ChecksumCapabilities::ignored();
checksum.udp = Checksum::Tx;
checksum.ipv4 = Checksum::Tx;
checksum.tcp = Checksum::Tx;
let mut external_buffer = vec![0u8; 2048];
loop {
let deadline = tokio::time::sleep(Duration::from_secs(UDP_TIMEOUT_SECS));
let selection = select! {
x = rx_receiver.recv() => if let Some(data) = x {
ProxyNatSelect::Internal(data)
} else {
ProxyNatSelect::Closed
ProxyNatSelect::Close
},
x = socket.read(&mut external_buffer) => ProxyNatSelect::External(x?),
_ = deadline => ProxyNatSelect::Close,
};
match selection {
@ -119,8 +122,14 @@ impl ProxyUdpHandler {
let udp = UdpSlice::from_slice(ip.payload)?;
socket.write_all(udp.payload()).await?;
}
ProxyNatSelect::Closed => warn!("UDP socket closed"),
ProxyNatSelect::Close => {
drop(socket);
reclaim_sender.send(key).await?;
break;
}
}
}
Ok(())
}
}