Workaround broken join_multicast_v4 on ESP-IDF

examples/onoff_light/src/main.rs

@@ -77,13 +77,14 @@ fn run() -> Result<(), Error> {
         device_name: "OnOff Light",
     };
 
-    let (ipv4_addr, ipv6_addr) = initialize_network()?;
+    let (ipv4_addr, ipv6_addr, interface) = initialize_network()?;
 
     let mdns = DefaultMdns::new(
         0,
         "matter-demo",
         ipv4_addr.octets(),
         Some(ipv6_addr.octets()),
+        interface,
         &dev_det,
         matter::MATTER_PORT,
     );
@@ -231,7 +232,7 @@ fn initialize_logger() {
 
 #[cfg(not(target_os = "espidf"))]
 #[inline(never)]
-fn initialize_network() -> Result<(Ipv4Addr, Ipv6Addr), Error> {
+fn initialize_network() -> Result<(Ipv4Addr, Ipv6Addr, u32), Error> {
     use log::error;
     use matter::error::ErrorCode;
     use nix::{net::if_::InterfaceFlags, sys::socket::SockaddrIn6};
@@ -276,7 +277,7 @@ fn initialize_network() -> Result<(Ipv4Addr, Ipv6Addr), Error> {
         iname, ip, ipv6
     );
 
-    Ok((ip, ipv6))
+    Ok((ip, ipv6, 0 as _))
 }
 
 #[cfg(target_os = "espidf")]
@@ -287,7 +288,7 @@ fn initialize_logger() {
 
 #[cfg(target_os = "espidf")]
 #[inline(never)]
-fn initialize_network() -> Result<(Ipv4Addr, Ipv6Addr), Error> {
+fn initialize_network() -> Result<(Ipv4Addr, Ipv6Addr, u32), Error> {
     use core::time::Duration;
 
     use embedded_svc::wifi::{AuthMethod, ClientConfiguration, Configuration};
@@ -379,9 +380,11 @@ fn initialize_network() -> Result<(Ipv4Addr, Ipv6Addr), Error> {
         ipv6.addr[3].to_le_bytes()[3],
     ];
 
+    let interface = wifi.sta_netif().get_index();
+
     // Not OK of course, but for a demo this is good enough
     // Wifi will continue to be available and working in the background
     core::mem::forget(wifi);
 
-    Ok((ipv4_octets.into(), ipv6_octets.into()))
+    Ok((ipv4_octets.into(), ipv6_octets.into(), interface))
 }

matter/src/mdns/astro.rs

@@ -23,6 +23,7 @@ impl<'a> Mdns<'a> {
         _hostname: &str,
         _ip: [u8; 4],
         _ipv6: Option<[u8; 16]>,
+        _interface: u32,
         dev_det: &'a BasicInfoConfig<'a>,
         matter_port: u16,
     ) -> Self {

matter/src/mdns/builtin.rs

@@ -19,21 +19,19 @@ use super::{
     Service, ServiceMode,
 };
 
-const IP_BROADCAST_ADDRS: [(IpAddr, u16); 2] = [
+const IP_BIND_ADDR: IpAddr = IpAddr::V6(Ipv6Addr::UNSPECIFIED);
-    (IpAddr::V4(Ipv4Addr::new(224, 0, 0, 251)), 5353),
-    (
-        IpAddr::V6(Ipv6Addr::new(0xff02, 0, 0, 0, 0, 0, 0, 0x00fb)),
-        5353,
-    ),
-];
 
-const IP_BIND_ADDR: (IpAddr, u16) = (IpAddr::V6(Ipv6Addr::UNSPECIFIED), 5353);
+const IP_BROADCAST_ADDR: Ipv4Addr = Ipv4Addr::new(224, 0, 0, 251);
+const IPV6_BROADCAST_ADDR: Ipv6Addr = Ipv6Addr::new(0xff02, 0, 0, 0, 0, 0, 0, 0x00fb);
+
+const PORT: u16 = 5353;
 
 type MdnsTxBuf = MaybeUninit<[u8; MAX_TX_BUF_SIZE]>;
 type MdnsRxBuf = MaybeUninit<[u8; MAX_RX_BUF_SIZE]>;
 
 pub struct Mdns<'a> {
     host: Host<'a>,
+    interface: u32,
     dev_det: &'a BasicInfoConfig<'a>,
     matter_port: u16,
     services: RefCell<heapless::Vec<(heapless::String<40>, ServiceMode), 4>>,
@@ -47,6 +45,7 @@ impl<'a> Mdns<'a> {
         hostname: &'a str,
         ip: [u8; 4],
         ipv6: Option<[u8; 16]>,
+        interface: u32,
         dev_det: &'a BasicInfoConfig<'a>,
         matter_port: u16,
     ) -> Self {
@@ -57,6 +56,7 @@ impl<'a> Mdns<'a> {
                 ip,
                 ipv6,
             },
+            interface,
             dev_det,
             matter_port,
             services: RefCell::new(heapless::Vec::new()),
@@ -121,11 +121,10 @@ impl<'a> MdnsRunner<'a> {
         let tx_pipe = &tx_pipe;
         let rx_pipe = &rx_pipe;
 
-        let mut udp = UdpListener::new(SocketAddr::new(IP_BIND_ADDR.0, IP_BIND_ADDR.1)).await?;
+        let mut udp = UdpListener::new(SocketAddr::new(IP_BIND_ADDR, PORT)).await?;
 
-        for (ip, _) in IP_BROADCAST_ADDRS {
+        udp.join_multicast_v6(IPV6_BROADCAST_ADDR, self.0.interface)?;
-            udp.join_multicast(ip).await?;
+        udp.join_multicast_v4(IP_BROADCAST_ADDR, Ipv4Addr::from(self.0.host.ip))?;
-        }
 
         let udp = &udp;
 
@@ -188,7 +187,10 @@ impl<'a> MdnsRunner<'a> {
             )
             .await;
 
-            for (addr, port) in IP_BROADCAST_ADDRS {
+            for addr in [
+                IpAddr::V4(IP_BROADCAST_ADDR),
+                IpAddr::V6(IPV6_BROADCAST_ADDR),
+            ] {
                 loop {
                     let sent = {
                         let mut data = tx_pipe.data.lock().await;
@@ -197,12 +199,12 @@ impl<'a> MdnsRunner<'a> {
                             let len = self.0.host.broadcast(&self.0, data.buf, 60)?;
 
                             if len > 0 {
-                                info!("Broadasting mDNS entry to {}:{}", addr, port);
+                                info!("Broadasting mDNS entry to {}:{}", addr, PORT);
 
                                 data.chunk = Some(Chunk {
                                     start: 0,
                                     end: len,
-                                    addr: Address::Udp(SocketAddr::new(addr, port)),
+                                    addr: Address::Udp(SocketAddr::new(addr, PORT)),
                                 });
 
                                 tx_pipe.data_supplied_notification.signal(());

matter/src/transport/udp.rs

@@ -27,7 +27,7 @@ mod smol_udp {
     use log::{debug, info, warn};
     use smol::net::UdpSocket;
 
-    use crate::transport::network::{IpAddr, Ipv4Addr, SocketAddr};
+    use crate::transport::network::{Ipv4Addr, Ipv6Addr, SocketAddr};
 
     pub struct UdpListener {
         socket: UdpSocket,
@@ -44,15 +44,71 @@ mod smol_udp {
             Ok(listener)
         }
 
-        pub async fn join_multicast(&mut self, ip_addr: IpAddr) -> Result<(), Error> {
+        pub fn join_multicast_v6(
-            match ip_addr {
+            &mut self,
-                IpAddr::V4(ip_addr) => self
+            multiaddr: Ipv6Addr,
-                    .socket
+            interface: u32,
-                    .join_multicast_v4(ip_addr, Ipv4Addr::UNSPECIFIED)?,
+        ) -> Result<(), Error> {
-                IpAddr::V6(ip_addr) => self.socket.join_multicast_v6(&ip_addr, 0)?,
+            self.socket.join_multicast_v6(&multiaddr, interface)?;
+
+            info!("Joined IPV6 multicast {}/{}", multiaddr, interface);
+
+            Ok(())
+        }
+
+        pub fn join_multicast_v4(
+            &mut self,
+            multiaddr: Ipv4Addr,
+            interface: Ipv4Addr,
+        ) -> Result<(), Error> {
+            #[cfg(not(target_os = "espidf"))]
+            self.socket.join_multicast_v4(multiaddr, interface)?;
+
+            // join_multicast_v4() is broken for ESP-IDF, most likely due to wrong `ip_mreq` signature in the `libc` crate
+            // Note that also most *_multicast_v4 and *_multicast_v6 methods are broken as well in Rust STD for the ESP-IDF
+            // due to mismatch w.r.t. sizes (u8 expected but u32 passed to setsockopt() and sometimes the other way around)
+            #[cfg(target_os = "espidf")]
+            {
+                fn esp_setsockopt<T>(
+                    socket: &mut UdpSocket,
+                    proto: u32,
+                    option: u32,
+                    value: T,
+                ) -> Result<(), Error> {
+                    use std::os::fd::AsRawFd;
+
+                    esp_idf_sys::esp!(unsafe {
+                        esp_idf_sys::lwip_setsockopt(
+                            socket.as_raw_fd(),
+                            proto as _,
+                            option as _,
+                            &value as *const _ as *const _,
+                            core::mem::size_of::<T>() as _,
+                        )
+                    })
+                    .map_err(|_| ErrorCode::StdIoError)?;
+
+                    Ok(())
+                }
+
+                let mreq = esp_idf_sys::ip_mreq {
+                    imr_multiaddr: esp_idf_sys::in_addr {
+                        s_addr: u32::from_ne_bytes(multiaddr.octets()),
+                    },
+                    imr_interface: esp_idf_sys::in_addr {
+                        s_addr: u32::from_ne_bytes(interface.octets()),
+                    },
+                };
+
+                esp_setsockopt(
+                    &mut self.socket,
+                    esp_idf_sys::IPPROTO_IP,
+                    esp_idf_sys::IP_ADD_MEMBERSHIP,
+                    mreq,
+                )?;
             }
 
-            info!("Joining multicast on {:?}", ip_addr);
+            info!("Joined IP multicast {}/{}", multiaddr, interface);
 
             Ok(())
         }