Allow avahi support using dns-sd for Discovery

.gitignore

@@ -2,3 +2,5 @@ target
 .cargo
 spotify_appkey.key
 .vagrant/
+.settings/
+.project

Cargo.toml

@@ -31,12 +31,14 @@ path = "protocol"
 
 [dependencies]
 base64 = "0.5.0"
+cfg-if = "0.1.2"
+dns-sd = { version  = "~0.1.3", optional = true }
 env_logger = "0.4.0"
 futures = "0.1.8"
 getopts = "0.2.14"
 hyper = "0.11.2"
 log = "0.3.5"
-mdns = { git = "https://github.com/plietar/rust-mdns" }
+mdns = { git = "https://github.com/plietar/rust-mdns", optional = true }
 num-bigint = "0.1.35"
 protobuf = "1.1"
 rand = "0.3.13"
@@ -66,7 +68,10 @@ pulseaudio-backend = ["libpulse-sys"]
 with-tremor = ["librespot-audio/with-tremor"]
 with-lewton = ["librespot-audio/with-lewton"]
 
-default = ["portaudio-backend"]
+with-internal-mdns = ["mdns"]
+with-external-mdns = ["dns-sd"]
+
+default = ["portaudio-backend", "with-internal-mdns"]
 
 [package.metadata.deb]
 maintainer = "nobody"

README.md

@@ -58,6 +58,11 @@ The following backends are currently available :
 - PortAudio 
 - PulseAudio
 
+## mdns - Internal or External
+*librespot* allows for the use of external avahi mdns. Internal or External mdns can be specified at compile time using
+`--feature "with-internal-mdns"` or `--feature "with-external-mdns"` respectively. The internal mdns is used by default if none is specified. Currently, it is not possible to build without mdns.
+`libavahi-compat-libdnssd-dev` must be installed to compile with-external-mdns.
+
 ## Cross-compiling
 A cross compilation environment is provided as a docker image.
 Build the image from the root of the project with the following command :

contrib/Dockerfile

@@ -4,6 +4,8 @@
 #
 # The resulting image can be used to build librespot for linux x86_64, armhf and armel.
 # $ docker run -v /tmp/librespot-build:/build librespot-cross
+# To build librespot with avahi support
+# $ docker run -v /tmp/librespot-build:/build librespot-cross /src/contrib/docker-build-avahi.sh
 #
 # The compiled binaries will be located in /tmp/librespot-build
 #
@@ -23,6 +25,7 @@ RUN apt-get update
 
 RUN apt-get install -y curl git build-essential crossbuild-essential-arm64 crossbuild-essential-armel crossbuild-essential-armhf crossbuild-essential-mipsel
 RUN apt-get install -y libasound2-dev libasound2-dev:arm64 libasound2-dev:armel libasound2-dev:armhf libasound2-dev:mipsel
+RUN apt-get install -y libavahi-compat-libdnssd-dev libavahi-compat-libdnssd-dev:arm64 libavahi-compat-libdnssd-dev:armel libavahi-compat-libdnssd-dev:armhf libavahi-compat-libdnssd-dev:mipsel
 
 RUN curl https://sh.rustup.rs -sSf | sh -s -- -y
 ENV PATH="/root/.cargo/bin/:${PATH}"

contrib/docker-build-avahi.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -eux
+
+cargo build --release --no-default-features --features "alsa-backend with-external-mdns"
+cp /usr/lib/x86_64-linux-gnu/libdns_sd.so.1 /build/release
+
+export PKG_CONFIG_ALLOW_CROSS=0
+
+export PKG_CONFIG_PATH=/usr/lib/aarch64-unknown-linux-gnu/pkgconfig
+cargo build --release --target aarch64-unknown-linux-gnu --no-default-features --features "alsa-backend with-external-mdns"
+cp /usr/lib/aarch64-linux-gnu/libdns_sd.so.1 /build/aarch64-unknown-linux-gnu/release
+
+export PKG_CONFIG_PATH=/usr/lib/arm-linux-gnueabi/pkgconfig
+cargo build --release --target arm-unknown-linux-gnueabi --no-default-features --features "alsa-backend with-external-mdns"
+cp /usr/lib/arm-linux-gnueabi/libdns_sd.so.1 /build/arm-unknown-linux-gnueabi/release
+
+export PKG_CONFIG_PATH=/usr/lib/arm-linux-gnueabihf/pkgconfig
+cargo build --release --target arm-unknown-linux-gnueabihf --no-default-features --features "alsa-backend with-external-mdns"
+cp /usr/lib/arm-linux-gnueabihf/libdns_sd.so.1 /build/arm-unknown-linux-gnueabihf/release
+
+export PKG_CONFIG_PATH=/usr/lib/mipsel-linux-gnu/pkgconfig
+cargo build --release --target mipsel-unknown-linux-gnu --no-default-features --features "alsa-backend with-external-mdns"
+cp /usr/libmipsel-linux-gnu/libdns_sd.so.1 /build/mipsel-unknown-linux-gnu/release
+

src/discovery.rs

@@ -6,7 +6,6 @@ use futures::sync::mpsc;
 use futures::{Future, Stream, BoxFuture, Poll, Async};
 use hyper::server::{Service, NewService, Request, Response, Http};
 use hyper::{self, Get, Post, StatusCode};
-use mdns;
 use num_bigint::BigUint;
 use rand;
 use std::collections::BTreeMap;
@@ -21,6 +20,16 @@ use core::authentication::Credentials;
 use core::util;
 use core::config::ConnectConfig;
 
+cfg_if! {
+    if #[cfg(feature = "with-internal-mdns")] {
+        use mdns;
+    } else if #[cfg(feature = "with-external-mdns")] {
+        use dns_sd::DNSService;
+    } else {
+        use mdns;
+    }
+}
+
 #[derive(Clone)]
 struct Discovery(Arc<DiscoveryInner>);
 struct DiscoveryInner {
@@ -201,39 +210,117 @@ impl NewService for Discovery {
     }
 }
 
-pub struct DiscoveryStream {
-    credentials: mpsc::UnboundedReceiver<Credentials>,
-    _svc: mdns::Service,
-    task: Box<Future<Item=(), Error=io::Error>>,
+cfg_if! {
+    if #[cfg(feature = "with-internal-mdns")] {
+            pub struct DiscoveryStream {
+                credentials: mpsc::UnboundedReceiver<Credentials>,
+                _svc: mdns::Service,
+                task: Box<Future<Item=(), Error=io::Error>>,
+            }
+        } else if #[cfg(feature = "with-external-mdns")] {
+            pub struct DiscoveryStream {
+                credentials: mpsc::UnboundedReceiver<Credentials>,
+                _svc: DNSService,
+                task: Box<Future<Item=(), Error=io::Error>>,
+            }
+        } else {
+            pub struct DiscoveryStream {
+                credentials: mpsc::UnboundedReceiver<Credentials>,
+                _svc: mdns::Service,
+                task: Box<Future<Item=(), Error=io::Error>>,
+            }
+        }
 }
 
-pub fn discovery(handle: &Handle, config: ConnectConfig, device_id: String)
-    -> io::Result<DiscoveryStream>
-{
-    let (discovery, creds_rx) = Discovery::new(config.clone(), device_id);
-
-    let listener = TcpListener::bind(&"0.0.0.0:0".parse().unwrap(), handle)?;
-    let addr = listener.local_addr()?;
-
-    let http = Http::new();
-    let handle_ = handle.clone();
-    let task = Box::new(listener.incoming().for_each(move |(socket, addr)| {
-        http.bind_connection(&handle_, socket, addr, discovery.clone());
-        Ok(())
-    }));
-
-    let responder = mdns::Responder::spawn(&handle)?;
-    let svc = responder.register(
-        "_spotify-connect._tcp".to_owned(),
-        config.name,
-        addr.port(),
-        &["VERSION=1.0", "CPath=/"]);
-
-    Ok(DiscoveryStream {
-        credentials: creds_rx,
-        _svc: svc,
-        task: task,
-    })
+cfg_if! {
+    if #[cfg(feature = "with-internal-mdns")] {
+        pub fn discovery(handle: &Handle, config: ConnectConfig, device_id: String)
+            -> io::Result<DiscoveryStream>
+        {
+            let (discovery, creds_rx) = Discovery::new(config.clone(), device_id);
+
+            let listener = TcpListener::bind(&"0.0.0.0:0".parse().unwrap(), handle)?;
+            let addr = listener.local_addr()?;
+
+            let http = Http::new();
+            let handle_ = handle.clone();
+            let task = Box::new(listener.incoming().for_each(move |(socket, addr)| {
+                http.bind_connection(&handle_, socket, addr, discovery.clone());
+                Ok(())
+            }));
+
+            let responder = mdns::Responder::spawn(&handle)?;
+            let svc = responder.register(
+                "_spotify-connect._tcp".to_owned(),
+                config.name,
+                addr.port(),
+                &["VERSION=1.0", "CPath=/"]);
+
+            Ok(DiscoveryStream {
+                credentials: creds_rx,
+                _svc: svc,
+                task: task,
+            })
+        }
+    } else if #[cfg(feature = "with-external-mdns")] {
+        pub fn discovery(handle: &Handle, config: ConnectConfig, device_id: String)
+            -> io::Result<DiscoveryStream>
+        {
+            let (discovery, creds_rx) = Discovery::new(config.clone(), device_id);
+
+            let listener = TcpListener::bind(&"0.0.0.0:0".parse().unwrap(), handle)?;
+            let port = listener.local_addr().unwrap().port();
+
+            let http = Http::new();
+            let handle_ = handle.clone();
+            let task = Box::new(listener.incoming().for_each(move |(socket, addr)| {
+                http.bind_connection(&handle_, socket, addr, discovery.clone());
+                Ok(())
+            }));
+
+            let svc = DNSService::register(Some(&*config.name),
+                                           "_spotify-connect._tcp",
+                                           None,
+                                           None,
+                                           port,
+                                           &["VERSION=1.0", "CPath=/"]).unwrap();
+
+            Ok(DiscoveryStream {
+                credentials: creds_rx,
+                _svc: svc,
+                task: task,
+            })
+        }
+        } else {
+        pub fn discovery(handle: &Handle, config: ConnectConfig, device_id: String)
+            -> io::Result<DiscoveryStream>
+        {
+            let (discovery, creds_rx) = Discovery::new(config.clone(), device_id);
+
+            let listener = TcpListener::bind(&"0.0.0.0:0".parse().unwrap(), handle)?;
+            let addr = listener.local_addr()?;
+
+            let http = Http::new();
+            let handle_ = handle.clone();
+            let task = Box::new(listener.incoming().for_each(move |(socket, addr)| {
+                http.bind_connection(&handle_, socket, addr, discovery.clone());
+                Ok(())
+            }));
+
+            let responder = mdns::Responder::spawn(&handle)?;
+            let svc = responder.register(
+                "_spotify-connect._tcp".to_owned(),
+                config.name,
+                addr.port(),
+                &["VERSION=1.0", "CPath=/"]);
+
+            Ok(DiscoveryStream {
+                credentials: creds_rx,
+                _svc: svc,
+                task: task,
+            })
+        }
+        }
 }
 
 impl Stream for DiscoveryStream {
@@ -248,4 +335,4 @@ impl Stream for DiscoveryStream {
 
         Ok(self.credentials.poll().unwrap())
     }
-}
+}

src/lib.rs

@@ -5,6 +5,7 @@
 // TODO: many items from tokio-core::io have been deprecated in favour of tokio-io
 #![allow(deprecated)]
 
+#[macro_use] extern crate cfg_if;
 #[macro_use] extern crate log;
 #[macro_use] extern crate serde_json;
 #[macro_use] extern crate serde_derive;
@@ -13,7 +14,6 @@ extern crate base64;
 extern crate crypto;
 extern crate futures;
 extern crate hyper;
-extern crate mdns;
 extern crate num_bigint;
 extern crate protobuf;
 extern crate rand;
@@ -34,6 +34,16 @@ extern crate portaudio_rs;
 #[cfg(feature = "libpulse-sys")]
 extern crate libpulse_sys;
 
+cfg_if! {
+    if #[cfg(feature = "with-internal-mdns")] {
+    	extern crate mdns;
+    } else if #[cfg(feature = "with-external-mdns")] {
+        extern crate dns_sd;
+    } else {
+        extern crate mdns;
+    }
+}
+
 pub mod audio_backend;
 pub mod discovery;
 pub mod keymaster;