Not to use link-local addrs if routable addrs exist (#117)

* And bump up to rustc 1.60.0

.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: 1.55.0
+          toolchain: 1.60.0
           override: true
           components: rustfmt, clippy
       - name: Run rustfmt and fail if any warnings

Cargo.toml

@@ -17,7 +17,7 @@ default = ["async", "logging"]
 
 [dependencies]
 flume = { version = "0.10", default-features = false } # channel between threads
-if-addrs = "0.7"                                       # get local IP addresses
+if-addrs = "0.10"                                       # get local IP addresses
 log = { version = "0.4.14", optional = true }          # logging
 polling = "2.1"                                        # select/poll sockets
 socket2 = { version = "0.4", features = ["all"] }      # socket APIs

README.md

@@ -32,7 +32,7 @@ Currently this library has the following limitations:
 
 ## Minimum Rust version
 
-Tested against Rust 1.55.0
+Tested against Rust 1.60.0
 
 ## License
 

src/service_daemon.rs

@@ -1672,20 +1672,36 @@ fn call_listener(
 
 /// Returns valid IPv4 interfaces in the host system.
 fn my_ipv4_interfaces() -> Vec<Ifv4Addr> {
-    if_addrs::get_if_addrs()
+    // Link local interfaces have the 169.254/16 prefix,
+    // see RFC 3927 for details.
+    let mut link_local_count = 0;
+
+    let mut intf_vec: Vec<Ifv4Addr> = if_addrs::get_if_addrs()
         .unwrap_or_default()
         .into_iter()
         .filter_map(|i| {
             if i.is_loopback() {
                 None
             } else {
+                if i.is_link_local() {
+                    link_local_count += 1;
+                }
                 match i.addr {
                     IfAddr::V4(ifv4) => Some(ifv4),
                     _ => None,
                 }
             }
         })
-        .collect()
+        .collect();
+
+    // If we have both routable interfaces and link-local interfaces,
+    // we only keep the routable interfaces. Otherwise, it can confuse
+    // the clients.
+    if link_local_count > 0 && intf_vec.len() > link_local_count {
+        intf_vec.retain(|i| !i.is_link_local())
+    }
+
+    intf_vec
 }
 
 /// Sends out `packet` to `addr` on the socket in `intf_sock`.

tests/mdns_test.rs

@@ -632,16 +632,22 @@ fn instance_name_two_dots() {
 }
 
 fn my_ipv4_interfaces() -> Vec<Ifv4Addr> {
+    let mut link_local_count = 0;
+
     // Use a random port for binding test.
     let test_port = fastrand::u16(8000u16..9000u16);
 
-    if_addrs::get_if_addrs()
+    let mut intf_vec: Vec<Ifv4Addr> = if_addrs::get_if_addrs()
         .unwrap_or_default()
         .into_iter()
         .filter_map(|i| {
             if i.is_loopback() {
                 None
             } else {
+                if i.is_link_local() {
+                    link_local_count += 1;
+                }
+
                 match i.addr {
                     IfAddr::V4(ifv4) =>
                     // Use a 'bind' to check if this is a valid IPv4 addr.
@@ -658,7 +664,13 @@ fn my_ipv4_interfaces() -> Vec<Ifv4Addr> {
                 }
             }
         })
-        .collect()
+        .collect();
+
+    if link_local_count > 0 && intf_vec.len() > link_local_count {
+        intf_vec.retain(|i| !i.is_link_local())
+    }
+
+    intf_vec
 }
 
 /// Returns a made-up IPv4 address "net.1.1.1", where