Trying to talk to legacy js & go IPFS mDNS implementations

misc/mdns/src/behaviour.rs

@@ -60,6 +60,15 @@ impl<TSubstream> Mdns<TSubstream> {
             marker: PhantomData,
         })
     }
+    /// Builds a new `Mdns` behaviour with legacy IPFS support
+    pub fn new_with_legacy() -> io::Result<Mdns<TSubstream>> {
+        Ok(Mdns {
+            service: MdnsService::new_with_legacy()?,
+            discovered_nodes: SmallVec::new(),
+            closest_expiration: None,
+            marker: PhantomData,
+        })
+    }
 
     /// Returns true if the given `PeerId` is in the list of nodes discovered through mDNS.
     pub fn has_node(&self, peer_id: &PeerId) -> bool {
@@ -240,7 +249,7 @@ where
                             if let Some(new_addr) = params.nat_traversal(&addr, &observed) {
                                 addrs.push(new_addr);
                             }
-                            addrs.push(addr);
+                            addrs.push(addr.clone());
                         }
 
                         for addr in addrs {

misc/mdns/src/dns.rs

@@ -21,7 +21,7 @@
 //! Contains methods that handle the DNS encoding and decoding capabilities not available in the
 //! `dns_parser` library.
 
-use crate::{META_QUERY_SERVICE, SERVICE_NAME};
+use crate::{META_QUERY_SERVICE, SERVICE_NAME, LEGACY_SERVICE_NAME_GO, LEGACY_SERVICE_NAME_JS};
 use data_encoding;
 use libp2p_core::{Multiaddr, PeerId};
 use rand;
@@ -49,7 +49,19 @@ pub fn decode_character_string(mut from: &[u8]) -> Result<Cow<'_, [u8]>, ()> {
 
 /// Builds the binary representation of a DNS query to send on the network.
 pub fn build_query() -> Vec<u8> {
-    let mut out = Vec::with_capacity(33);
+    build_query_inner(SERVICE_NAME)
+}
+
+/// Builds the binary representations of legacy DNS queries to send on the network.
+pub fn build_legacy_queries() -> (Vec<u8>, Vec<u8>) {
+    return (
+        build_query_inner(LEGACY_SERVICE_NAME_JS),
+        build_query_inner(LEGACY_SERVICE_NAME_GO)
+    )
+}
+
+fn build_query_inner(name: &[u8]) -> Vec<u8> {
+    let mut out = vec![];
 
     // Program-generated transaction ID; unused by our implementation.
     append_u16(&mut out, rand::random());
@@ -67,15 +79,12 @@ pub fn build_query() -> Vec<u8> {
 
     // Our single question.
     // The name.
-    append_qname(&mut out, SERVICE_NAME);
+    append_qname(&mut out, name);
 
     // Flags.
     append_u16(&mut out, 0x0c);
     append_u16(&mut out, 0x01);
 
-    // Since the output is constant, we reserve the right amount ahead of time.
-    // If this assert fails, adjust the capacity of `out` in the source code.
-    debug_assert_eq!(out.capacity(), out.len());
     out
 }
 
@@ -86,7 +95,7 @@ pub fn build_query_response(
     id: u16,
     peer_id: PeerId,
     addresses: impl ExactSizeIterator<Item = Multiaddr>,
-    ttl: Duration,
+    ttl: Duration
 ) -> Result<Vec<u8>, MdnsResponseError> {
     // Convert the TTL into seconds.
     let ttl = duration_to_secs(ttl);
@@ -147,6 +156,7 @@ pub fn build_query_response(
     Ok(out)
 }
 
+
 /// Builds the response to the DNS query.
 pub fn build_service_discovery_response(id: u16, ttl: Duration) -> Vec<u8> {
     // Convert the TTL into seconds.

misc/mdns/src/lib.rs

@@ -32,6 +32,10 @@
 
 /// Hardcoded name of the mDNS service. Part of the mDNS libp2p specifications.
 const SERVICE_NAME: &[u8] = b"_p2p._udp.local";
+/// Hardcoded name of the mDNS service as used by legacy IPFS services in GO
+const LEGACY_SERVICE_NAME_GO: &[u8] = b"_ipfs-discovery._udp.local";
+/// Hardcoded name of the mDNS service as used by legacy IPFS services in JS
+const LEGACY_SERVICE_NAME_JS: &[u8] = b"ipfs.local";
 /// Hardcoded name of the service used for DNS-SD.
 const META_QUERY_SERVICE: &[u8] = b"_services._dns-sd._udp.local";