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fallback.rs
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fallback.rs
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use crate::IfEvent;
use async_io::Timer;
use futures::stream::Stream;
use if_addrs::IfAddr;
use ipnet::{IpNet, Ipv4Net, Ipv6Net};
use std::collections::{HashSet, VecDeque};
use std::future::Future;
use std::io::Result;
use std::pin::Pin;
use std::task::{Context, Poll};
use std::time::{Duration, Instant};
/// An address set/watcher
#[derive(Debug)]
pub struct IfWatcher {
addrs: HashSet<IpNet>,
queue: VecDeque<IfEvent>,
ticker: Timer,
}
impl IfWatcher {
/// Create a watcher
pub async fn new() -> Result<Self> {
Ok(Self {
addrs: Default::default(),
queue: Default::default(),
ticker: Timer::interval_at(Instant::now(), Duration::from_secs(10)),
})
}
fn resync(&mut self) -> Result<()> {
let addrs = if_addrs::get_if_addrs()?;
for old_addr in self.addrs.clone() {
if addrs.iter().any(|addr| addr.ip() == old_addr.addr()) {
self.addrs.remove(&old_addr);
self.queue.push_back(IfEvent::Down(old_addr));
}
}
for new_addr in addrs {
let ipnet = ifaddr_to_ipnet(new_addr.addr);
if self.addrs.insert(ipnet) {
self.queue.push_back(IfEvent::Up(ipnet));
}
}
Ok(())
}
pub fn iter(&self) -> impl Iterator<Item = &IpNet> {
self.addrs.iter()
}
pub fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<IfEvent>> {
loop {
if let Some(event) = self.queue.pop_front() {
return Poll::Ready(Ok(event));
}
if Pin::new(&mut self.ticker).poll_next(cx).is_pending() {
return Poll::Pending;
}
if let Err(err) = self.resync() {
return Poll::Ready(Err(err));
}
}
}
}
fn ifaddr_to_ipnet(addr: IfAddr) -> IpNet {
match addr {
IfAddr::V4(ip) => {
let prefix_len = (!u32::from_be_bytes(ip.netmask.octets())).leading_zeros();
IpNet::V4(
Ipv4Net::new(ip.ip, prefix_len as u8).expect("if_addrs returned a valid prefix"),
)
}
IfAddr::V6(ip) => {
let prefix_len = (!u128::from_be_bytes(ip.netmask.octets())).leading_zeros();
IpNet::V6(
Ipv6Net::new(ip.ip, prefix_len as u8).expect("if_addrs returned a valid prefix"),
)
}
}
}