fix(server): filter out /quic in favor of /quic-v1

Configuration files generated by Kubo <= v0.22 list both `/quic` and `/quic-v1` listen
addresses with the same UDP port. Given that we enable draft-29, the two addresses are
treated the same by rust-libp2p's QUIC implementation. Though calling `listen_on` with
both results in an "Address already in use" error by the OS on the second call. To
prevent this from happening filter out `/quic` addresses in favor of `/quic-v1`.

misc/server/src/main.rs

@@ -12,11 +12,13 @@ use libp2p::identity;
 use libp2p::identity::PeerId;
 use libp2p::kad;
 use libp2p::metrics::{Metrics, Recorder};
+use libp2p::multiaddr::Protocol;
 use libp2p::noise;
 use libp2p::quic;
 use libp2p::swarm::{SwarmBuilder, SwarmEvent};
 use libp2p::tcp;
 use libp2p::yamux;
+use libp2p::Multiaddr;
 use libp2p::Transport;
 use log::{debug, info, warn};
 use prometheus_client::metrics::info::Info;
@@ -114,10 +116,35 @@ async fn main() -> Result<(), Box<dyn Error>> {
     );
     let mut swarm = SwarmBuilder::with_tokio_executor(transport, behaviour, local_peer_id).build();
 
-    if config.addresses.swarm.is_empty() {
-        warn!("No listen addresses configured.");
-    }
-    for address in &config.addresses.swarm {
+    let listen_addresses = {
+        let addresses = config.addresses.swarm.clone();
+        if addresses.is_empty() {
+            warn!("No listen addresses configured.");
+        }
+        // Configuration files generated by Kubo <= v0.22 list both `/quic` and `/quic-v1` listen
+        // addresses with the same UDP port. Given that we enable draft-29, the two addresses are
+        // treated the same by rust-libp2p's QUIC implementation. Though calling `listen_on` with
+        // both results in an "Address already in use" error by the OS on the second call. To
+        // prevent this from happening filter out `/quic` addresses in favor of `/quic-v1`.
+        let mut addresses = addresses
+            .into_iter()
+            .map(|a| {
+                a.into_iter()
+                    .map(|p| {
+                        if p == Protocol::Quic {
+                            Protocol::QuicV1
+                        } else {
+                            p
+                        }
+                    })
+                    .collect()
+            })
+            .collect::<Vec<Multiaddr>>();
+        addresses.sort();
+        addresses.dedup();
+        addresses
+    };
+    for address in listen_addresses {
         match swarm.listen_on(address.clone()) {
             Ok(_) => {}
             Err(e @ libp2p::TransportError::MultiaddrNotSupported(_)) => {
@@ -126,6 +153,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
             Err(e) => return Err(e.into()),
         }
     }
+
     if config.addresses.append_announce.is_empty() {
         warn!("No external addresses configured.");
     }