fix for macOS: exclude IFF_POINTTOPOINT interfaces and exclude Apple P2P interfaces by default

Cargo.toml

@@ -20,7 +20,7 @@ default = ["reuseport", "async", "logging"]
 [dependencies]
 fastrand = "2.3"
 flume = { version = "0.11", default-features = false } # channel between threads
-if-addrs = { version = "0.14", features = ["link-local"] } # get local IP addresses
+if-addrs = { version = "0.15", features = ["link-local"] } # get local IP addresses
 log = { version = "0.4", optional = true }             # logging
 mio = { version = "1.1", features = ["os-poll", "net"] }  # select/poll sockets
 socket2 = { version = "0.6", features = ["all"] }      # socket APIs

examples/register.rs

@@ -26,6 +26,7 @@ fn main() {
     let mut should_unreg = false;
     let mut disable_ipv6 = false;
     let mut use_logfile = false;
+    let mut include_apple_p2p = false;
 
     for arg in args.iter() {
         if arg.as_str() == "--unregister" {
@@ -34,6 +35,8 @@ fn main() {
             disable_ipv6 = true;
         } else if arg.as_str() == "--logfile" {
             use_logfile = true;
+        } else if arg.as_str() == "--include-apple-p2p" {
+            include_apple_p2p = true;
         }
     }
 
@@ -60,6 +63,10 @@ fn main() {
         mdns.disable_interface(IfKind::IPv6).unwrap();
     }
 
+    if include_apple_p2p {
+        mdns.include_apple_p2p(true).unwrap();
+    }
+
     let service_type = match args.get(1) {
         Some(arg) => format!("{}.local.", arg),
         None => {
@@ -140,6 +147,7 @@ fn print_usage() {
     println!("--unregister: automatically unregister after 2 seconds");
     println!("--disable-ipv6: not to use IPv6 interfaces.");
     println!("--logfile: write debug log to a file instead of stderr. The logfile is named 'mdns-register-<timestamp>.log'.");
+    println!("--include-apple-p2p: include Apple p2p interfaces (e.g., awdl, llw) for mDNS.");
     println!();
     println!("For example:");
     println!("cargo run --example register _my-hello._udp instance1 host1");

src/service_daemon.rs

@@ -570,6 +570,12 @@ impl ServiceDaemon {
         self.send_cmd(Command::SetOption(DaemonOption::AcceptUnsolicited(accept)))
     }
 
+    /// Include or exclude Apple P2P interfaces, e.g. "awdl0", "llw0".
+    /// By default, they are excluded.
+    pub fn include_apple_p2p(&self, include: bool) -> Result<()> {
+        self.send_cmd(Command::SetOption(DaemonOption::IncludeAppleP2P(include)))
+    }
+
     #[cfg(test)]
     pub fn test_down_interface(&self, ifname: &str) -> Result<()> {
         self.send_cmd(Command::SetOption(DaemonOption::TestDownInterface(
@@ -942,6 +948,8 @@ struct Zeroconf {
 
     accept_unsolicited: bool,
 
+    include_apple_p2p: bool,
+
     cmd_sender: Sender<Command>,
 
     signal_addr: SocketAddr,
@@ -1118,6 +1126,7 @@ impl Zeroconf {
             multicast_loop_v4: true,
             multicast_loop_v6: true,
             accept_unsolicited: false,
+            include_apple_p2p: false,
             cmd_sender,
             signal_addr,
 
@@ -1404,6 +1413,7 @@ impl Zeroconf {
             DaemonOption::MulticastLoopV4(on) => self.set_multicast_loop_v4(on),
             DaemonOption::MulticastLoopV6(on) => self.set_multicast_loop_v6(on),
             DaemonOption::AcceptUnsolicited(accept) => self.set_accept_unsolicited(accept),
+            DaemonOption::IncludeAppleP2P(enable) => self.set_apple_p2p(enable),
             #[cfg(test)]
             DaemonOption::TestDownInterface(ifname) => {
                 self.test_down_interfaces.insert(ifname);
@@ -1424,7 +1434,7 @@ impl Zeroconf {
             });
         }
 
-        self.apply_intf_selections(my_ip_interfaces(true));
+        self.apply_intf_selections(my_ip_interfaces_inner(true, self.include_apple_p2p));
     }
 
     fn disable_interface(&mut self, kinds: Vec<IfKind>) {
@@ -1436,7 +1446,7 @@ impl Zeroconf {
             });
         }
 
-        self.apply_intf_selections(my_ip_interfaces(true));
+        self.apply_intf_selections(my_ip_interfaces_inner(true, self.include_apple_p2p));
     }
 
     fn set_multicast_loop_v4(&mut self, on: bool) {
@@ -1465,6 +1475,13 @@ impl Zeroconf {
         self.accept_unsolicited = accept;
     }
 
+    fn set_apple_p2p(&mut self, include: bool) {
+        if self.include_apple_p2p != include {
+            self.include_apple_p2p = include;
+            self.apply_intf_selections(my_ip_interfaces_inner(true, self.include_apple_p2p));
+        }
+    }
+
     fn notify_monitors(&mut self, event: DaemonEvent) {
         // Only retain the monitors that are still connected.
         self.monitors.retain(|sender| {
@@ -1573,7 +1590,7 @@ impl Zeroconf {
     /// Check for IP changes and update [my_intfs] as needed.
     fn check_ip_changes(&mut self) {
         // Get the current interfaces.
-        let my_ifaddrs = my_ip_interfaces(true);
+        let my_ifaddrs = my_ip_interfaces_inner(true, self.include_apple_p2p);
 
         #[cfg(test)]
         let my_ifaddrs: Vec<_> = my_ifaddrs
@@ -1869,7 +1886,8 @@ impl Zeroconf {
         }
 
         if info.is_addr_auto() {
-            let selected_intfs = self.selected_intfs(my_ip_interfaces(true));
+            let selected_intfs =
+                self.selected_intfs(my_ip_interfaces_inner(true, self.include_apple_p2p));
             for intf in selected_intfs {
                 info.insert_ipaddr(&intf);
             }
@@ -3922,6 +3940,7 @@ enum DaemonOption {
     MulticastLoopV4(bool),
     MulticastLoopV6(bool),
     AcceptUnsolicited(bool),
+    IncludeAppleP2P(bool),
     #[cfg(test)]
     TestDownInterface(String),
     #[cfg(test)]
@@ -4044,13 +4063,29 @@ fn call_hostname_resolution_listener(
 /// Operational down interfaces are excluded.
 /// Loopback interfaces are excluded if `with_loopback` is false.
 fn my_ip_interfaces(with_loopback: bool) -> Vec<Interface> {
+    my_ip_interfaces_inner(with_loopback, false)
+}
+
+fn my_ip_interfaces_inner(with_loopback: bool, with_apple_p2p: bool) -> Vec<Interface> {
     if_addrs::get_if_addrs()
         .unwrap_or_default()
         .into_iter()
-        .filter(|i| i.is_oper_up() && (!i.is_loopback() || with_loopback))
+        .filter(|i| {
+            i.is_oper_up()
+                && !i.is_p2p()
+                && (!i.is_loopback() || with_loopback)
+                && (with_apple_p2p || !is_apple_p2p_by_name(&i.name))
+        })
         .collect()
 }
 
+/// Checks if the interface name indicates it's an Apple peer-to-peer interface,
+/// which should be ignored by default.
+fn is_apple_p2p_by_name(name: &str) -> bool {
+    let p2p_prefixes = ["awdl", "llw"];
+    p2p_prefixes.iter().any(|prefix| name.starts_with(prefix))
+}
+
 /// Send an outgoing mDNS query or response, and returns the packet bytes.
 /// Returns empty vec if no valid interface address is found.
 fn send_dns_outgoing(
@@ -4116,6 +4151,7 @@ fn send_dns_outgoing_impl(
                         addr: if_addr.clone(),
                         index: Some(if_index),
                         oper_status: if_addrs::IfOperStatus::Down,
+                        is_p2p: false,
                         #[cfg(windows)]
                         adapter_name: String::new(),
                     };
@@ -4137,6 +4173,7 @@ fn send_dns_outgoing_impl(
                         addr: if_addr.clone(),
                         index: Some(if_index),
                         oper_status: if_addrs::IfOperStatus::Down,
+                        is_p2p: false,
                         #[cfg(windows)]
                         adapter_name: String::new(),
                     };

src/service_info.rs

@@ -1547,6 +1547,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };
@@ -1561,6 +1562,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };
@@ -1575,6 +1577,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };
@@ -1589,6 +1592,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };
@@ -1605,6 +1609,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };
@@ -1619,6 +1624,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };
@@ -1633,6 +1639,7 @@ mod tests {
                 prefixlen: 16,
             }),
             oper_status: IfOperStatus::Up,
+            is_p2p: false,
             #[cfg(windows)]
             adapter_name: String::new(),
         };

tests/mdns_test.rs

@@ -1173,6 +1173,11 @@ fn service_new_publish_after_browser() {
     daemon.shutdown().unwrap();
 }
 
+fn is_apple_p2p_by_name(name: &str) -> bool {
+    let p2p_prefixes = ["awdl", "llw"];
+    p2p_prefixes.iter().any(|prefix| name.starts_with(prefix))
+}
+
 fn my_ip_interfaces() -> Vec<Interface> {
     // Use a random port for binding test.
     let test_port = fastrand::u16(8000u16..9000u16);
@@ -1181,7 +1186,7 @@ fn my_ip_interfaces() -> Vec<Interface> {
         .unwrap_or_default()
         .into_iter()
         .filter_map(|i| {
-            if i.is_loopback() {
+            if i.is_loopback() || i.is_p2p() || is_apple_p2p_by_name(&i.name) {
                 None
             } else {
                 match &i.addr {