eculocate

commit 7696ac0277cdd685429501da59c1675444a93ee0
parent 39df2730b9f0640bbb86a37819a67397fdaba02d
Author: Daniel Barlow <dan@telent.net>
Date:   Tue, 30 Dec 2025 23:56:51 +0000

handle unicast (QU) and legacy (post != 5353) queries

Diffstat:
M
ecu-esp32/src/wifi.rs
 | 
32
++++++++++++++++++++++++++------
M
notes.md
 | 
22
+---------------------

2 files changed, 27 insertions(+), 27 deletions(-)
diff --git a/ecu-esp32/src/wifi.rs b/ecu-esp32/src/wifi.rs
@@ -113,15 +113,11 @@ impl<'a> MdnsResponder<'a> {
 			   question: Option<&Question<'_>>,
 			   answers: Vec<&DnsResource>) {
 
-	let questions = match question {
-	    Some(q) =>&mut [*q][..],
-	    None => &mut [][..]
-	};
+	let legacy = question != None;
 
 	let db = &self.database;
 	let mut flags = Flags::new();
 
-
 	flags.set_qr(MessageType::Reply);
 	flags.set_authoritative(true);
 
@@ -143,6 +139,22 @@ impl<'a> MdnsResponder<'a> {
 	}
 
 	let mut additional : Vec<ResourceRecord> = additional.into_iter().collect();
+
+	let questions = match question {
+	    Some(q) =>&mut [*q][..],
+	    None => &mut [][..]
+	};
+
+	if legacy {
+	    // force class = IN (no cache-flush) and ttl to 10 seconds
+	    answers = answers.iter().map(|rr| {
+		ResourceRecord::new(rr.name(), rr.ty(), 1, 10, rr.data())
+	    }).collect();
+	    additional = additional.iter().map(|rr| {
+		ResourceRecord::new(rr.name(), rr.ty(), 1, 10, rr.data())
+	    }).collect();
+	}
+
 	let message = Message::new(
 	    id,
 	    flags,
@@ -183,7 +195,15 @@ impl<'a> MdnsResponder<'a> {
 			   message.flags().raw(),
 			   meta.endpoint);
 
-		self.send_response(q_id, MDNS_ENDPOINT, None, relevant).await
+		let unicast = (q.class() & (1<<15)) != 0;
+		let legacy = meta.endpoint.port != 5353;
+		if legacy {
+		    self.send_response(q_id, meta.endpoint, Some(q), relevant).await
+		} else if unicast {
+		    self.send_response(0, meta.endpoint, None, relevant).await
+		} else {
+		    self.send_response(0, MDNS_ENDPOINT, None, relevant).await
+		}
 	    }
 	}
     }
diff --git a/notes.md b/notes.md
@@ -200,28 +200,10 @@ but not the PTR records because other devices could also legitimately
 have those
 
 
-
-
 ** do we need to do NSEC?
 
 ** handle QU and legacy queries
 
-	// RFC: "Multicast DNS responses MUST NOT contain any questions in the
-	// Question Section. ". However, responses to "legacy" queries (port != 5353)
-	// should have a question section just like traditional DNS
-	if q.name().eq(&Label::from("&my_hostname")) {
-	    // if meta.endpoint.port == 5353 {
-	    // 	send_advert(&sock, q_id, MDNS_ENDPOINT, None, &my_address).await;
-	    // } else if (q.class() & 0x8000) != 0 {
-	    // 	log::info!("unicast");
-	    // 	send_advert(&sock, q_id, meta.endpoint, None,  &my_address).await;
-	    // } else {
-	    // 	// legacy unicast, send questions
-	    // 	send_advert(&sock, q_id, meta.endpoint, Some(q),  &my_address).await;
-	    // }
-	    // log::info!("IT ME");
-	}
-
 5.4 Questions Requesting Unicast Responses
 
 - top bit in the class field of a DNS question is the unicast-response bit
@@ -241,11 +223,9 @@ if source port != 5353
 - don't set cache-flush bit
 - ttl <= 10s
 
-
-
-
 ** compress responses
 
+
 * write the udp server
 
 - on reception of a packet containing table numbers, start streaming those