Implement sys_publish_service for Linux based on libmdns

matter/Cargo.toml

@@ -47,6 +47,10 @@ safemem = "0.3.3"
 chrono = { version = "0.4.19", default-features = false, features = ["clock", "std"] }
 async-channel = "1.6"
 
+[target.'cfg(target_os = "linux")'.dependencies]
+libmdns = "0.7"
+lazy_static = "1.4.0"
+
 [target.'cfg(target_os = "macos")'.dependencies]
 astro-dnssd = "0.3"
 

matter/src/sys/sys_linux.rs

@@ -1,15 +1,46 @@
 use crate::error::Error;
-use log::error;
+use std::vec::Vec;
+use log::info;
+use lazy_static::lazy_static;
+use std::sync::{Arc, Mutex};
+use libmdns::{Service, Responder};
 
 #[allow(dead_code)]
-pub struct SysMdnsService {}
+pub struct SysMdnsService {
+    service: Service,
+}
+
+lazy_static!{
+    static ref RESPONDER: Arc<Mutex<Responder>> = Arc::new(Mutex::new(Responder::new().unwrap()));
+}
 
+/// Publish a mDNS service
+/// name - can be a service name (comma separate subtypes may follow)
+/// regtype - registration type (e.g. _matter_.tcp etc)
+/// port - the port
 pub fn sys_publish_service(
-    _name: &str,
-    _regtype: &str,
-    _port: u16,
-    _txt_kvs: &[[&str; 2]],
+    name: &str,
+    regtype: &str,
+    port: u16,
+    txt_kvs: &[[&str; 2]],
 ) -> Result<SysMdnsService, Error> {
-    error!("Linux is not yet supported for MDNS Service");
-    Ok(SysMdnsService {})
+    info!("mDNS Registration Type {}", regtype);
+    info!("mDNS properties {:?}", txt_kvs);
+
+    let mut properties = Vec::new();
+    for kvs in txt_kvs {
+        info!("mDNS TXT key {} val {}", kvs[0], kvs[1]);
+        properties.push(format!("{}={}", kvs[0], kvs[1]));
+    }
+    let properties: Vec<&str> = properties.iter().map(|entry| entry.as_str()).collect();
+
+    let responder = RESPONDER.lock().map_err(|_| Error::MdnsError)?;
+    let service = responder.register(
+        regtype.to_owned(),
+        name.to_owned(),
+        port,
+        &properties,
+    );
+
+    Ok(SysMdnsService {service})
 }