dns: properly handle AddrType::Either in get_host_by_name()

1 files changed, 19 insertions, 4 deletions

diff --git a/embassy-net/src/dns.rs b/embassy-net/src/dns.rs
index a1151d5e4..8ccfa4e4f 100644
--- a/embassy-net/src/dns.rs
+++ b/embassy-net/src/dns.rs
@@ -84,11 +84,26 @@ where
         addr_type: embedded_nal_async::AddrType,
     ) -> Result<embedded_nal_async::IpAddr, Self::Error> {
         use embedded_nal_async::{AddrType, IpAddr};
-        let qtype = match addr_type {
-            AddrType::IPv6 => DnsQueryType::Aaaa,
-            _ => DnsQueryType::A,
+        let (qtype, secondary_qtype) = match addr_type {
+            AddrType::IPv4 => (DnsQueryType::A, None),
+            AddrType::IPv6 => (DnsQueryType::Aaaa, None),
+            AddrType::Either => {
+                #[cfg(not(feature = "proto-ipv6"))]
+                let v6_first = false;
+                #[cfg(feature = "proto-ipv6")]
+                let v6_first = self.stack.config_v6().is_some();
+                match v6_first {
+                    true => (DnsQueryType::Aaaa, Some(DnsQueryType::A)),
+                    false => (DnsQueryType::A, Some(DnsQueryType::Aaaa)),
+                }
+            }
         };
-        let addrs = self.query(host, qtype).await?;
+        let mut addrs = self.query(host, qtype).await?;
+        if addrs.is_empty() {
+            if let Some(qtype) = secondary_qtype {
+                addrs = self.query(host, qtype).await?
+            }
+        }
         if let Some(first) = addrs.get(0) {
             Ok(match first {
                 #[cfg(feature = "proto-ipv4")]