From f581831b86f1f3e46a1cc7a8c4d1a2baf3379e6a Mon Sep 17 00:00:00 2001
From: bjoernQ <bjoern.quentin@mobile-j.de>
Date: Tue, 18 Jul 2023 10:39:29 +0200
Subject: [PATCH] Make dual-stack work in embassy-net

---
 embassy-net/src/lib.rs | 39 ++++++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/embassy-net/src/lib.rs b/embassy-net/src/lib.rs
index 0d0a986f..f43e3797 100644
--- a/embassy-net/src/lib.rs
+++ b/embassy-net/src/lib.rs
@@ -531,11 +531,14 @@ impl<D: Driver + 'static> Inner<D> {
 
         debug!("   IP address:      {}", config.address);
         s.iface.update_ip_addrs(|addrs| {
-            if addrs.is_empty() {
-                addrs.push(IpCidr::Ipv4(config.address)).unwrap();
-            } else {
-                addrs[0] = IpCidr::Ipv4(config.address);
+            if let Some((index, _)) = addrs
+                .iter()
+                .enumerate()
+                .find(|(_, &addr)| matches!(addr, IpCidr::Ipv4(_)))
+            {
+                addrs.remove(index);
             }
+            addrs.push(IpCidr::Ipv4(config.address)).unwrap();
         });
 
         #[cfg(feature = "medium-ethernet")]
@@ -570,11 +573,14 @@ impl<D: Driver + 'static> Inner<D> {
 
         debug!("   IP address:      {}", config.address);
         s.iface.update_ip_addrs(|addrs| {
-            if addrs.is_empty() {
-                addrs.push(IpCidr::Ipv6(config.address)).unwrap();
-            } else {
-                addrs[0] = IpCidr::Ipv6(config.address);
+            if let Some((index, _)) = addrs
+                .iter()
+                .enumerate()
+                .find(|(_, &addr)| matches!(addr, IpCidr::Ipv6(_)))
+            {
+                addrs.remove(index);
             }
+            addrs.push(IpCidr::Ipv6(config.address)).unwrap();
         });
 
         #[cfg(feature = "medium-ethernet")]
@@ -643,12 +649,19 @@ impl<D: Driver + 'static> Inner<D> {
     }
 
     #[allow(unused)] // used only with dhcp
-    fn unapply_config(&mut self, s: &mut SocketStack) {
+    fn unapply_config_v4(&mut self, s: &mut SocketStack) {
         #[cfg(feature = "medium-ethernet")]
         let medium = self.device.capabilities().medium;
-
         debug!("Lost IP configuration");
-        s.iface.update_ip_addrs(|ip_addrs| ip_addrs.clear());
+        s.iface.update_ip_addrs(|ip_addrs| {
+            if let Some((index, _)) = ip_addrs
+                .iter()
+                .enumerate()
+                .find(|(index, &addr)| matches!(addr, IpCidr::Ipv4(_)))
+            {
+                ip_addrs.remove(index);
+            }
+        });
         #[cfg(feature = "medium-ethernet")]
         if medium == Medium::Ethernet {
             #[cfg(feature = "proto-ipv4")]
@@ -695,7 +708,7 @@ impl<D: Driver + 'static> Inner<D> {
             if self.link_up {
                 match socket.poll() {
                     None => {}
-                    Some(dhcpv4::Event::Deconfigured) => self.unapply_config(s),
+                    Some(dhcpv4::Event::Deconfigured) => self.unapply_config_v4(s),
                     Some(dhcpv4::Event::Configured(config)) => {
                         let config = StaticConfigV4 {
                             address: config.address,
@@ -707,7 +720,7 @@ impl<D: Driver + 'static> Inner<D> {
                 }
             } else if old_link_up {
                 socket.reset();
-                self.unapply_config(s);
+                self.unapply_config_v4(s);
             }
         }
         //if old_link_up || self.link_up {