288 lines
8.1 KiB
Rust

use std::{
collections::VecDeque,
net::{Ipv4Addr, SocketAddr},
time::Duration,
};
use anyhow::{anyhow, bail};
use log::{debug, error, info, trace};
use nl_sys::{netlink, route};
use packets::{
self, ARPMode, ARPPacket, ARPProto, EthernetPacket, IPv4Packet, IPv4Pkt, Layer3Packet,
Layer3Pkt, Layer4Packet, Layer4Pkt, TCPPacket, TCPPacketBuilder, TCPPkt,
};
use pcap_sys;
use tokio::{sync::mpsc, task};
use tokio_stream::StreamExt;
struct PeerInfo {
remote_addr: Ipv4Addr,
remote_port: u16,
local_addr: Ipv4Addr,
local_port: u16,
}
#[derive(Default)]
struct TcpSocket {
tx_buffer: VecDeque<u8>,
rx_buffer: VecDeque<u8>,
local_seq_no: u32,
remote_seq_no: u32,
remote_last_ack: Option<u32>,
remote_last_win: u16,
local_rx_last_seq: Option<u32>,
local_rx_last_ack: Option<u32>,
state: TcpState,
peer_info: Option<PeerInfo>,
ack_timeout: Option<Duration>,
}
#[derive(Default)]
enum TcpState {
Listen,
SynSent,
SynReceived,
Established,
FinWait1,
FinWait2,
CloseWait,
Closing,
LastAck,
TimeWait,
#[default]
Closed,
}
enum TcpOptions {
EndOfList,
NoOp,
MaxSegmentSize(u16),
}
impl TcpOptions {
fn get_bytes(&self) -> Vec<u8> {
match self {
Self::EndOfList => vec![0x00],
Self::NoOp => vec![0x01],
Self::MaxSegmentSize(size) => [&[0x02, 0x04][..], &size.to_be_bytes()].concat(),
}
}
}
fn socket_accepts_packet(socket: &TcpSocket, ip: &IPv4Pkt<'_>, tcp: &TCPPkt<'_>) -> bool {
if let Some(peer) = &socket.peer_info {
peer.local_addr == ip.dest_ip()
&& peer.remote_addr == ip.source_ip()
&& peer.local_port == tcp.dstport()
&& peer.remote_port == tcp.srcport()
} else {
false
}
}
fn connect(
socket: &mut TcpSocket,
remote_addr: Ipv4Addr,
remote_port: u16,
local_addr: Ipv4Addr,
) -> (u16, TCPPacket) {
socket.state = TcpState::SynSent;
let local_port: u16 = loop {
let port = rand::random();
if port > 40000 {
break port;
}
};
socket.peer_info = Some(PeerInfo {
remote_addr,
remote_port,
local_addr,
local_port,
});
socket.local_seq_no = rand::random();
let packet = TCPPacketBuilder::default()
.srcport(local_port)
.dstport(remote_port)
.syn(true)
.window(64240)
.seqnumber(socket.local_seq_no)
//.options([TcpOptions::MaxSegmentSize(64240).get_bytes()].concat())
.build(local_addr, remote_addr, vec![], None);
(local_port, packet)
}
fn process_packet(
socket: &mut TcpSocket,
packet: TCPPkt<'_>,
) -> anyhow::Result<(Option<(TCPPacketBuilder, Vec<u8>)>, Option<Vec<u8>>)> {
match socket.state {
TcpState::SynSent if packet.ack() && packet.syn() => {}
_ => {}
}
Ok((None, None))
}
fn send_data(
socket: &mut TcpSocket,
data: Vec<u8>,
) -> anyhow::Result<Option<(TCPPacketBuilder, Vec<u8>)>> {
Ok(None)
}
struct TcpSocketHandle {
send_channel: mpsc::Sender<Vec<u8>>,
receiver_channel: mpsc::Receiver<Vec<u8>>,
}
async fn use_socket(mut socket_handle: TcpSocketHandle) {
_ = socket_handle.send_channel.send(b"ping".to_vec()).await;
match socket_handle.receiver_channel.recv().await {
Some(bytes) => match std::str::from_utf8(&bytes) {
Ok(string) => {
log::info!("received packet: {string}")
}
Err(_) => {
log::info!("received packet: {bytes:?}");
}
},
None => {
log::error!("could not get packets from server")
}
}
}
#[tokio::main]
async fn main() -> anyhow::Result<()> {
simple_logger::SimpleLogger::new()
.with_level(log::LevelFilter::Trace)
.with_module_level("tcp_test", log::LevelFilter::Trace)
.init()?;
let ip = std::env::args()
.skip(1)
.next()
.ok_or(anyhow!("could not get target IP"))?
.parse::<Ipv4Addr>()?;
let (ifname, _, srcip, src_mac, dst_mac, _) = {
let socket = netlink::Socket::new()?;
let routes = socket.get_routes()?;
let neighs = socket.get_neigh()?;
let links = socket.get_links()?;
let addrs = socket.get_addrs()?;
route::get_macs_and_src_for_ip(&addrs, &routes, &neighs, &links, ip)
.ok_or(anyhow!("unable to find a route to the IP"))?
};
let mut socket = TcpSocket::default();
let mut interface = pcap_sys::Interface::<pcap_sys::DevDisabled>::new(&ifname)?;
let srcip: u32 = srcip.into();
let srcip = srcip + 10;
let srcip: Ipv4Addr = srcip.into();
dbg!(srcip, src_mac, dst_mac);
let dst_mac = [0x00, 0x16, 0x3e, 0xde, 0xa9, 0x93];
interface.set_buffer_size(8192)?;
interface.set_non_blocking(true)?;
interface.set_promisc(false)?;
interface.set_timeout(10)?;
let interface = interface.activate()?;
macro_rules! format_packet {
($tcp_packet:expr) => {{
let ippkt = IPv4Packet::construct(srcip, ip, &Layer4Packet::TCP($tcp_packet));
EthernetPacket::construct(src_mac, dst_mac, &Layer3Packet::IPv4(ippkt))
}};
}
let (port, packet) = connect(&mut socket, ip, 54248, srcip);
interface.set_filter(&format!("arp or (inbound and tcp port {port})"), true, None)?;
if interface.datalink() != pcap_sys::consts::DLT_EN10MB {
bail!("interface does not support ethernet");
}
let mut packets = interface.stream()?;
packets.sendpacket(format_packet!(packet).pkt())?;
let (send_channel, mut send_packet) = mpsc::channel(1024);
let (receive_packet, receiver_channel) = mpsc::channel(1024);
let socket_handle = TcpSocketHandle {
receiver_channel,
send_channel,
};
task::spawn(async move { use_socket(socket_handle) });
loop {
let Some(packet) = tokio::select! {
Some(Ok(bytes)) = packets.next() => {
let pkt = bytes.pkt();
match pkt.get_layer3_pkt() {
Ok(Layer3Pkt::IPv4Pkt(ip_pkt)) => {
let Ok(Layer4Pkt::TCP(tcp_pkt)) = ip_pkt.get_layer4_packet() else { continue; };
if !socket_accepts_packet(&socket, &ip_pkt, &tcp_pkt) {
continue;
}
let Ok((to_send, received)) = process_packet(&mut socket, tcp_pkt) else { continue; };
if let Some(received) = received {
_ = receive_packet.send(received).await;
}
to_send.map(|(b, d)| format_packet!(b.build(srcip, ip, d, None)))
},
Ok(Layer3Pkt::ARP(arp)) => {
if arp.opcode() != 1 || arp.plen() != 4 || arp.hwlen() != 6 {
continue;
}
let senderip: [u8; 4] = arp.srcprotoaddr().try_into().unwrap();
let sendermac: &[u8] = arp.srchwaddr();
let queryip: [u8; 4] = arp.targetprotoaddr().try_into().unwrap();
let queryip: Ipv4Addr = queryip.into();
if queryip != srcip {
continue;
}
let response = ARPPacket::construct(ARPMode::Reply, ARPProto::IPv4, &src_mac, &sendermac, &queryip.octets(), &senderip);
Some(EthernetPacket::construct(src_mac, sendermac.try_into().unwrap(), &Layer3Packet::ARP(response)))
},
_ => continue
}
},
Some(to_send) = send_packet.recv() => {
match send_data(&mut socket, to_send) {
Ok(v) => v.map(|(b, d)| format_packet!(b.build(srcip, ip, d, None))),
Err(_) => continue
}
},
else => { continue; }
} else {
continue;
};
_ = packets.sendpacket(packet.pkt());
}
}