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use rsdsl_dhcp6::util::*;
use rsdsl_dhcp6::{Error, Result};
use std::fs::{self, File};
use std::net::{Ipv6Addr, SocketAddr, SocketAddrV6};
use std::str::FromStr;
use std::time::SystemTime;
use tokio::net::{ToSocketAddrs, UdpSocket};
use tokio::time::{self, Duration, Instant};
use dhcproto::v6::{duid::Duid, DhcpOption, IAPrefix, Message, MessageType, OptionCode, IAPD, ORO};
use dhcproto::{Decodable, Decoder, Encodable, Encoder, Name};
use rsdsl_ip_config::DsConfig;
use rsdsl_pd_config::PdConfig;
use socket2::{Domain, Socket, Type};
use sysinfo::{ProcessExt, Signal, System, SystemExt};
use trust_dns_proto::serialize::binary::BinDecodable;
const DUID_LOCATION: &str = "/data/dhcp6.duid";
const TICK_INTERVAL: u64 = 60;
const ALL_DHCPV6_SERVERS: SocketAddrV6 =
SocketAddrV6::new(Ipv6Addr::new(0xff02, 0, 0, 0, 0, 0, 1, 2), 547, 0, 0);
#[derive(Clone, Debug, Eq, PartialEq)]
struct Dhcp6 {
duid: Duid,
lease: Option<PdConfig>,
}
impl Dhcp6 {
fn load_from_disk() -> Result<Self> {
Ok(Self {
duid: load_or_generate_duid()?,
lease: load_lease_optional(),
})
}
}
fn load_or_generate_duid() -> Result<Duid> {
match fs::read(DUID_LOCATION) {
Ok(duid) => Ok(duid.into()),
Err(_) => {
let duid = Duid::uuid(&rand::random::<u128>().to_be_bytes());
fs::write(DUID_LOCATION, &duid)?;
Ok(duid)
}
}
}
fn load_lease_optional() -> Option<PdConfig> {
let mut file = File::open(rsdsl_pd_config::LOCATION).ok()?;
let lease = serde_json::from_reader(&mut file).ok();
lease.filter(|lease| !expired(lease))
}
#[tokio::main]
async fn main() -> Result<()> {
let dhcp6 = Dhcp6::load_from_disk()?;
let sock = Socket::new(Domain::IPV6, Type::DGRAM, None)?;
sock.set_only_v6(true)?;
sock.set_reuse_port(true)?;
sock.set_reuse_address(true)?;
let address = SocketAddr::from_str("[::]:546")?;
sock.bind(&address.into())?;
let sock: std::net::UdpSocket = sock.into();
let sock: UdpSocket = sock.try_into()?;
sock.bind_device(Some("ppp0".as_bytes()))?;
// If a valid lease is present on disk, inform netlinkd immediately.
if dhcp6.lease.is_some() {
for netlinkd in System::default().processes_by_exact_name("/bin/rsdsl_netlinkd") {
netlinkd.kill_with(Signal::User1);
}
}
let mut interval = time::interval(Duration::from_secs(TICK_INTERVAL));
let mut buf = [0; 1500];
loop {
tokio::select! {
result = sock.recv_from(&mut buf) => {
let (n, raddr) = result?;
let buf = &buf[..n];
logged_handle(&dhcp6, buf, raddr);
logged_tick(&sock, &dhcp6).await;
}
_ = interval.tick() => {
logged_tick(&sock, &dhcp6).await;
}
}
}
}
async fn logged_tick(sock: &UdpSocket, dhcp6: &Dhcp6) {
match tick(sock, dhcp6).await {
Ok(_) => {}
Err(e) => println!("[warn] tick: {}", e),
}
}
async fn tick(sock: &UdpSocket, dhcp6: &Dhcp6) -> Result<()> {
match &dhcp6.lease {
None => {
let mut solicit = Message::new(MessageType::Solicit);
let opts = solicit.opts_mut();
opts.insert(DhcpOption::ClientId(dhcp6.duid.as_ref().to_vec()));
opts.insert(DhcpOption::RapidCommit);
opts.insert(DhcpOption::IAPD(IAPD {
id: 1,
t1: 0,
t2: 0,
opts: Default::default(),
}));
opts.insert(DhcpOption::ORO(ORO {
opts: vec![OptionCode::AftrName, OptionCode::DomainNameServers],
}));
let mut buf = Vec::new();
solicit.encode(&mut Encoder::new(&mut buf))?;
send_to_exact(sock, &buf, ALL_DHCPV6_SERVERS).await?;
println!("[info] -> solicit");
Ok(())
}
Some(lease) => todo!(),
}
}
fn logged_handle(dhcp6: &Dhcp6, buf: &[u8], raddr: SocketAddr) {
match handle(dhcp6, buf, raddr) {
Ok(_) => {}
Err(e) => println!("[warn] handle from {}: {}", raddr, e),
}
}
fn handle(dhcp6: &Dhcp6, buf: &[u8], raddr: SocketAddr) -> Result<()> {
let msg = Message::decode(&mut Decoder::new(buf))?;
let client_id = match msg
.opts()
.get(OptionCode::ClientId)
.ok_or(Error::NoClientId)?
{
DhcpOption::ClientId(client_id) => client_id,
_ => unreachable!(),
};
if client_id != dhcp6.duid.as_ref() {
println!("[warn] <- [{}] client id mismatch", raddr);
return Ok(());
}
match msg.msg_type() {
_ => println!(
"[warn] <- [{}] unhandled message type {:?}",
raddr,
msg.msg_type()
),
}
Ok(())
}
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