discovery: allow limiting the advertised ip addresses

contrib/spotifyd.conf

@@ -56,6 +56,10 @@
 # zeroconf port need to be allowed through any active firewall.
 #zeroconf_port = 1234
 
+# The ip addresses that `spotifyd` advertises via mDNS. By default, the addresses
+# of all interfaces are advertised.
+#zeroconf_ip = ["192.168.0.10"]
+
 #-------#
 # AUDIO #
 #-------#

docs/src/configuration/auth.md

@@ -11,6 +11,8 @@ For this to work, you need to make sure that your firewall isn't blocking the di
 - `5353 UDP`: MDNS service advertisement
 - A zeroconf port which uses TCP. By default, it is randomly chosen, but if you want to, you can configure it with the `--zeroconf-port` cli option / `zeroconf_port` config value.
 
+By default, `spotifyd` advertises the addresses of all interfaces. On hosts with many of them, clients may pick one that they cannot reach, in which case you can limit the advertisement with the `--zeroconf-ip` cli option / `zeroconf_ip` config value.
+
 If you don't want discovery, because you're using one of the methods below, you can disable it via the `--disable-discovery` cli option / `disable_discovery = true` config value.
 
 > __Note:__ By default, the last active session will be remembered and reconnected once the service is restarted.

src/config.rs

@@ -25,6 +25,7 @@ use std::{
     borrow::Cow,
     convert::TryInto,
     fs,
+    net::IpAddr,
     path::{Path, PathBuf},
     str::FromStr,
 };
@@ -339,6 +340,10 @@ pub struct SharedConfigValues {
     #[arg(long)]
     zeroconf_port: Option<u16>,
 
+    /// The ip addresses to advertise for the Spotify Connect discovery
+    #[arg(long, value_name = "IP", value_delimiter = ',')]
+    zeroconf_ip: Option<Vec<IpAddr>>,
+
     /// The proxy used to connect to spotify's servers
     #[arg(long, value_name = "URL")]
     proxy: Option<String>,
@@ -583,6 +588,7 @@ impl SharedConfigValues {
             on_song_change_hook,
             disable_discovery,
             zeroconf_port,
+            zeroconf_ip,
             proxy,
             device_type,
             max_cache_size,
@@ -634,6 +640,7 @@ pub(crate) struct SpotifydConfig {
     pub(crate) shell: String,
     pub(crate) discovery: bool,
     pub(crate) zeroconf_port: Option<u16>,
+    pub(crate) zeroconf_ip: Option<Vec<IpAddr>>,
     pub(crate) device_type: LSDeviceType,
     #[cfg(feature = "dbus_mpris")]
     pub(crate) mpris: MprisConfig,
@@ -757,6 +764,7 @@ pub(crate) fn get_internal_config(config: CliConfig) -> SpotifydConfig {
         shell,
         discovery: !config.shared_config.disable_discovery.unwrap_or(false),
         zeroconf_port: config.shared_config.zeroconf_port,
+        zeroconf_ip: config.shared_config.zeroconf_ip,
         device_type,
         #[cfg(unix)]
         pid,

src/setup.rs

@@ -76,6 +76,7 @@ pub(crate) fn initial_state(
     let backend = config.backend.clone();
 
     let zeroconf_port = config.zeroconf_port.unwrap_or(0);
+    let zeroconf_ip = config.zeroconf_ip.unwrap_or_default();
 
     let creds = if let Some(creds) = config.oauth_cache.as_ref().and_then(|c| c.credentials()) {
         info!(
@@ -105,6 +106,7 @@ pub(crate) fn initial_state(
             .name(config.device_name.clone())
             .device_type(config.device_type)
             .port(zeroconf_port)
+            .zeroconf_ip(zeroconf_ip.clone())
             .launch()
             {
                 Ok(discovery_stream) => break Some(discovery_stream),