Files
lanspread/crates/lanspread-mdns/src/lib.rs
T

138 lines
4.1 KiB
Rust

#![allow(clippy::missing_errors_doc, clippy::missing_panics_doc)]
use std::net::SocketAddr;
use eyre::bail;
pub use mdns_sd::DaemonEvent;
use mdns_sd::{Receiver, ServiceDaemon, ServiceEvent, ServiceInfo};
pub const LANSPREAD_SERVICE_TYPE: &str = "_lanspread._udp.local.";
pub struct MdnsAdvertiser {
daemon: ServiceDaemon,
service_info: ServiceInfo,
pub monitor: Receiver<DaemonEvent>,
}
impl MdnsAdvertiser {
pub fn new(service_type: &str, instance_name: &str, address: SocketAddr) -> eyre::Result<Self> {
let host_name = format!("{}.local.", address.ip());
let daemon = ServiceDaemon::new()?;
let service_info = ServiceInfo::new(
service_type,
instance_name,
&host_name,
address.ip(),
address.port(),
None,
)?;
let monitor = daemon.monitor()?;
// Register the service
daemon.register(service_info.clone())?;
Ok(Self {
daemon,
service_info,
monitor,
})
}
}
impl Drop for MdnsAdvertiser {
fn drop(&mut self) {
let _ = self.daemon.unregister(self.service_info.get_fullname());
let _ = self.daemon.shutdown();
}
}
pub struct MdnsBrowser {
daemon: ServiceDaemon,
receiver: Receiver<ServiceEvent>,
service_type: String,
}
impl MdnsBrowser {
pub fn new(service_type: &str) -> eyre::Result<Self> {
let daemon = ServiceDaemon::new()?;
let receiver = daemon.browse(service_type)?;
Ok(Self {
daemon,
receiver,
service_type: service_type.to_string(),
})
}
pub fn next_address(
&self,
ignore_addr: Option<SocketAddr>,
) -> eyre::Result<Option<SocketAddr>> {
loop {
match self.receiver.recv() {
Ok(ServiceEvent::ServiceResolved(info)) => {
log::trace!("mdns ServiceResolved event: {info:?}");
if info.ty_domain != self.service_type {
log::trace!(
"Got mDNS with uninteresting service type: {} (expected: {})",
info.ty_domain,
self.service_type,
);
continue;
}
let mut ignored_match = false;
for address in info.get_addresses() {
let addr = SocketAddr::new(address.to_ip_addr(), info.get_port());
if ignore_addr.is_some_and(|ignore| ignore == addr) {
ignored_match = true;
log::trace!("Ignoring mDNS advertisement for local server at {addr}");
continue;
}
log::info!("Found server at {addr}");
return Ok(Some(addr));
}
if ignored_match {
log::trace!(
"Only saw ignored mDNS advertisements (probably ourselves) for {:?}",
info.get_fullname()
);
continue;
}
log::error!("No address found in mDNS response: {info:?}");
}
Ok(other_event) => {
log::trace!("mdns unrelated event: {other_event:?}");
}
Err(err) => {
log::error!("mDNS browse channel closed: {err}");
return Ok(None);
}
}
}
}
}
impl Drop for MdnsBrowser {
fn drop(&mut self) {
let _ = self.daemon.shutdown();
}
}
pub fn discover_service(
service_type: &str,
ignore_addr: Option<SocketAddr>,
) -> eyre::Result<SocketAddr> {
// Currently unused; kept for potential one-off discovery callers that just need a single address.
let browser = MdnsBrowser::new(service_type)?;
match browser.next_address(ignore_addr)? {
Some(addr) => Ok(addr),
None => bail!("No server found."),
}
}