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protomask/src/protomask-clat.rs

116 lines
3.7 KiB
Rust

//! Entrypoint for the `protomask-clat` binary.
//!
//! This binary is a Customer-side transLATor (CLAT) that translates all native
//! IPv4 traffic to IPv6 traffic for transmission over an IPv6-only ISP network.
use crate::common::packet_handler::handle_packet;
use crate::{args::protomask_clat::Args, common::permissions::ensure_root};
use clap::Parser;
use common::logging::enable_logger;
use easy_tun::Tun;
use interproto::protocols::ip::{translate_ipv4_to_ipv6, translate_ipv6_to_ipv4};
use ipnet::{IpNet, Ipv4Net, Ipv6Net};
use rfc6052::{embed_ipv4_addr_unchecked, extract_ipv4_addr_unchecked};
use std::io::{Read, Write};
mod args;
mod common;
#[tokio::main]
pub async fn main() {
// Parse CLI args
let args = Args::parse();
// Initialize logging
enable_logger(args.verbose);
// Load config data
let config = args.data().unwrap();
// We must be root to continue program execution
ensure_root();
// Bring up a TUN interface
let mut tun = Tun::new(&args.interface).unwrap();
// Get the interface index
let rt_handle = rtnl::new_handle().unwrap();
let tun_link_idx = rtnl::link::get_link_index(&rt_handle, tun.name())
.await
.unwrap()
.unwrap();
// Bring the interface up
rtnl::link::link_up(&rt_handle, tun_link_idx).await.unwrap();
// Add an IPv4 default route towards the interface
rtnl::route::route_add(IpNet::V4(Ipv4Net::default()), &rt_handle, tun_link_idx)
.await
.unwrap();
// Add an IPv6 route for each customer prefix
for customer_prefix in config.customer_pool {
let embedded_customer_prefix = unsafe {
Ipv6Net::new(
embed_ipv4_addr_unchecked(customer_prefix.addr(), config.embed_prefix),
config.embed_prefix.prefix_len() + customer_prefix.prefix_len(),
)
.unwrap_unchecked()
};
log::debug!(
"Adding route for {} to {}",
embedded_customer_prefix,
tun.name()
);
rtnl::route::route_add(
IpNet::V6(embedded_customer_prefix),
&rt_handle,
tun_link_idx,
)
.await
.unwrap();
}
// If we are configured to serve prometheus metrics, start the server
if let Some(bind_addr) = config.prom_bind_addr {
log::info!("Starting prometheus server on {}", bind_addr);
tokio::spawn(protomask_metrics::http::serve_metrics(bind_addr));
}
// Translate all incoming packets
log::info!("Translating packets on {}", tun.name());
let mut buffer = vec![0u8; 1500];
loop {
// Read a packet
let len = tun.read(&mut buffer).unwrap();
// Translate it based on the Layer 3 protocol number
if let Some(output) = handle_packet(
&buffer[..len],
// IPv4 -> IPv6
|packet, source, dest| {
Ok(translate_ipv4_to_ipv6(
packet,
unsafe { embed_ipv4_addr_unchecked(*source, config.embed_prefix) },
unsafe { embed_ipv4_addr_unchecked(*dest, config.embed_prefix) },
)
.map(Some)?)
},
// IPv6 -> IPv4
|packet, source, dest| {
Ok(translate_ipv6_to_ipv4(
packet,
unsafe {
extract_ipv4_addr_unchecked(*source, config.embed_prefix.prefix_len())
},
unsafe { extract_ipv4_addr_unchecked(*dest, config.embed_prefix.prefix_len()) },
)
.map(Some)?)
},
) {
// Write the packet if we get one back from the handler functions
tun.write_all(&output).unwrap();
}
}
}