From c93f774c93b80ddc710e62265868d5e57da03163 Mon Sep 17 00:00:00 2001
From: Simon Bernard <code@simonbernard.eu>
Date: Mon, 5 Feb 2024 15:46:55 +0100
Subject: [PATCH] GH-1580: ipv6 zone id in URI should be prefixed by %25.

---
 .../leshan/core/endpoint/EndpointUriUtil.java | 33 +++++++++++++++++--
 .../endpoint/CaliforniumServerEndpoint.java   |  3 +-
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/leshan-core/src/main/java/org/eclipse/leshan/core/endpoint/EndpointUriUtil.java b/leshan-core/src/main/java/org/eclipse/leshan/core/endpoint/EndpointUriUtil.java
index 9fc3dc9eae..791ce50561 100644
--- a/leshan-core/src/main/java/org/eclipse/leshan/core/endpoint/EndpointUriUtil.java
+++ b/leshan-core/src/main/java/org/eclipse/leshan/core/endpoint/EndpointUriUtil.java
@@ -15,6 +15,8 @@
  *******************************************************************************/
 package org.eclipse.leshan.core.endpoint;
 
+import java.net.Inet6Address;
+import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.net.URISyntaxException;
@@ -33,7 +35,7 @@ public static URI createUri(String scheme, String host, int port) {
 
     public static URI createUri(String scheme, InetSocketAddress addr) {
         try {
-            return new URI(scheme, null, addr.getHostString(), addr.getPort(), null, null, null);
+            return new URI(scheme, null, toUriHostName(addr), addr.getPort(), null, null, null);
         } catch (URISyntaxException e) {
             throw new IllegalStateException(e);
         }
@@ -49,7 +51,7 @@ public static URI createUri(String uri) {
 
     public static URI replaceAddress(URI originalUri, InetSocketAddress newAddress) {
         try {
-            return new URI(originalUri.getScheme(), null, newAddress.getHostString(), newAddress.getPort(), null, null,
+            return new URI(originalUri.getScheme(), null, toUriHostName(newAddress), newAddress.getPort(), null, null,
                     null);
         } catch (URISyntaxException e) {
             throw new IllegalStateException(e);
@@ -75,4 +77,31 @@ public static void validateURI(URI uri) throws IllegalArgumentException {
             throw new IllegalArgumentException(String.format("Invalid URI[%s]: Post MUST NOT be undefined", uri));
         }
     }
+
+    /**
+     * This convert socket address in URI hostname.
+     * <p>
+     * Following https://www.rfc-editor.org/rfc/rfc6874#section-2, zone id (also called scope id) in URI should be
+     * prefixed by <code>%25</code>
+     */
+    private static String toUriHostName(InetSocketAddress socketAddr) {
+        if (socketAddr == null) {
+            Validate.notNull(socketAddr);
+        }
+        InetAddress addr = socketAddr.getAddress();
+        String host = addr.getHostAddress();
+        if (addr instanceof Inet6Address) {
+            Inet6Address address6 = (Inet6Address) addr;
+            if (address6.getScopedInterface() != null || address6.getScopeId() > 0) {
+                int pos = host.indexOf('%');
+                if (pos > 0 && pos + 1 < host.length()) {
+                    String separator = "%25";
+                    String scope = host.substring(pos + 1);
+                    String hostAddress = host.substring(0, pos);
+                    host = hostAddress + separator + scope;
+                }
+            }
+        }
+        return host;
+    }
 }
diff --git a/leshan-server-cf/src/main/java/org/eclipse/leshan/server/californium/endpoint/CaliforniumServerEndpoint.java b/leshan-server-cf/src/main/java/org/eclipse/leshan/server/californium/endpoint/CaliforniumServerEndpoint.java
index 1c56d79224..fd8bed79ed 100644
--- a/leshan-server-cf/src/main/java/org/eclipse/leshan/server/californium/endpoint/CaliforniumServerEndpoint.java
+++ b/leshan-server-cf/src/main/java/org/eclipse/leshan/server/californium/endpoint/CaliforniumServerEndpoint.java
@@ -32,7 +32,6 @@
 import org.eclipse.leshan.core.californium.ExceptionTranslator;
 import org.eclipse.leshan.core.californium.SyncRequestObserver;
 import org.eclipse.leshan.core.californium.identity.IdentityHandler;
-import org.eclipse.leshan.core.endpoint.EndpointUriUtil;
 import org.eclipse.leshan.core.endpoint.Protocol;
 import org.eclipse.leshan.core.observation.Observation;
 import org.eclipse.leshan.core.request.DownlinkRequest;
@@ -86,7 +85,7 @@ public Protocol getProtocol() {
 
     @Override
     public URI getURI() {
-        return EndpointUriUtil.createUri(protocol.getUriScheme(), endpoint.getAddress());
+        return endpoint.getUri();
     }
 
     @Override