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use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
use std::time::{Duration, SystemTime};
use anyhow::{anyhow, bail, Result};
use log::*;
use serde::{Deserialize, Serialize};
use crate::config::{RuntimeConfigConsul, RuntimeConfigStun};
use crate::consul;
/// If autodiscovery returns None but an address was obtained less than
/// this number of seconds ago (here 15 minutes), we keep that address
/// in the Consul db instead of insterting a None.
const PERSIST_SOME_RESULT_DURATION_SECS: u64 = 900;
pub struct StunActor {
consul: consul::Consul,
refresh_time: Duration,
autodiscovery_v4: StunAutodiscovery,
autodiscovery_v6: StunAutodiscovery,
}
pub struct StunAutodiscovery {
consul_key: String,
is_ipv4: bool,
stun_server: Option<SocketAddr>,
last_result: Option<AutodiscoverResult>,
}
#[derive(Serialize, Deserialize, Debug)]
pub struct AutodiscoverResult {
pub timestamp: u64,
pub address: Option<IpAddr>,
}
impl StunActor {
pub fn new(
consul_config: &RuntimeConfigConsul,
stun_config: &RuntimeConfigStun,
node: &str,
) -> Self {
assert!(stun_config
.stun_server_v4
.map(|x| x.is_ipv4())
.unwrap_or(true));
assert!(stun_config.stun_server_v6.is_ipv6());
let autodiscovery_v4 = StunAutodiscovery {
consul_key: format!("diplonat/autodiscovery/ipv4/{}", node),
is_ipv4: true,
stun_server: stun_config.stun_server_v4,
last_result: None,
};
let autodiscovery_v6 = StunAutodiscovery {
consul_key: format!("diplonat/autodiscovery/ipv6/{}", node),
is_ipv4: false,
stun_server: Some(stun_config.stun_server_v6),
last_result: None,
};
Self {
consul: consul::Consul::new(consul_config),
autodiscovery_v4,
autodiscovery_v6,
refresh_time: stun_config.refresh_time,
}
}
pub async fn listen(&mut self) -> Result<()> {
loop {
if let Err(e) = self.autodiscovery_v4.do_iteration(&self.consul).await {
error!("Unable to autodiscover IPv4 address: {}", e);
}
if let Err(e) = self.autodiscovery_v6.do_iteration(&self.consul).await {
error!("Unable to autodiscover IPv6 address: {}", e);
}
tokio::time::sleep(self.refresh_time).await;
}
}
}
impl StunAutodiscovery {
async fn do_iteration(&mut self, consul: &consul::Consul) -> Result<()> {
let binding_ip = match self.is_ipv4 {
true => IpAddr::V4(Ipv4Addr::UNSPECIFIED), // 0.0.0.0
false => IpAddr::V6(Ipv6Addr::UNSPECIFIED), // [::]
};
let binding_addr = SocketAddr::new(binding_ip, 0);
let discovered_addr = match self.stun_server {
Some(stun_server) => {
assert_eq!(self.is_ipv4, stun_server.is_ipv4());
get_mapped_addr(stun_server, binding_addr)
.await?
.map(|x| x.ip())
}
None => None,
};
let now = timestamp();
if discovered_addr.is_none() {
if let Some(last_result) = &self.last_result {
if last_result.address.is_some()
&& now - last_result.timestamp <= PERSIST_SOME_RESULT_DURATION_SECS
{
// Keep non-None result that was obtained before by not
// writing/taking into account None result.
return Ok(());
}
}
}
let current_result = AutodiscoverResult {
timestamp: now,
address: discovered_addr,
};
consul
.kv_put(&self.consul_key, serde_json::to_vec(¤t_result)?)
.await?;
self.last_result = Some(current_result);
Ok(())
}
}
async fn get_mapped_addr(
stun_server: SocketAddr,
binding_addr: SocketAddr,
) -> Result<Option<SocketAddr>> {
use stun_client::*;
let mut client = Client::new(binding_addr, None).await?;
let res = match client.binding_request(stun_server, None).await {
Err(e) => {
info!(
"STUN binding request to {} failed, assuming no address (error: {})",
binding_addr, e
);
return Ok(None);
}
Ok(r) => r,
};
if res.get_class() != Class::SuccessResponse {
bail!("STUN server did not responde with a success response");
}
let xor_mapped_addr = Attribute::get_xor_mapped_address(&res)
.ok_or(anyhow!("no XorMappedAddress found in STUN response"))?;
Ok(Some(xor_mapped_addr))
}
fn timestamp() -> u64 {
SystemTime::now()
.duration_since(SystemTime::UNIX_EPOCH)
.expect("clock error")
.as_secs()
}
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