From fe16ccb4342d74bde19de1a35f86a597b975a6fb Mon Sep 17 00:00:00 2001
From: zzz <zzz@mail.i2p>
Date: Mon, 10 Feb 2020 14:43:57 +0000
Subject: [PATCH] Transport: Mark yggdrasil IPv6 prefix as not routable Minor
 cleanup of the checking code

---
 .../i2p/router/transport/TransportUtil.java   | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/router/java/src/net/i2p/router/transport/TransportUtil.java b/router/java/src/net/i2p/router/transport/TransportUtil.java
index 55f5f0e174..7ae32d7286 100644
--- a/router/java/src/net/i2p/router/transport/TransportUtil.java
+++ b/router/java/src/net/i2p/router/transport/TransportUtil.java
@@ -203,17 +203,23 @@ public abstract class TransportUtil {
                         if (addr[2] == 0x0d && (addr[3] & 0xff) == 0xb8)
                             return false;
                     }
+                } else if ((addr[0] & 0xfe) == 0xfc) {
+                    // disallow fc00::/8 and fd00::/8 (Unique local addresses RFC 4193)
+                    // not recognized as local by InetAddress
+                    return false;
+                } else if (addr[0] == 0x26) {
+                    // Hamachi IPv6
+                    if (addr[1] == 0x20 && addr[2] == 0x00 && (addr[3] & 0xff) == 0x9b)
+                        return false;
+                } else if (addr[0] == 0x3f) {
+                    // 6bone RFC 2471
+                    if ((addr[1] & 0xff) == 0xfe)
+                        return false;
+                } else if ((addr[0] & 0xfe) == 0x02) {
+                    // Yggdrasil 0200:/7
+                    // https://yggdrasil-network.github.io/faq.html
+                    return false;
                 }
-                // disallow fc00::/8 and fd00::/8 (Unique local addresses RFC 4193)
-                // not recognized as local by InetAddress
-                if ((addr[0] & 0xfe) == 0xfc)
-                    return false;
-                // Hamachi IPv6
-                if (addr[0] == 0x26 && addr[1] == 0x20 && addr[2] == 0x00 && (addr[3] & 0xff) == 0x9b)
-                    return false;
-                // 6bone RFC 2471
-                if (addr[0] == 0x3f && (addr[1] & 0xff) == 0xfe)
-                    return false;
                 try {
                     InetAddress ia = InetAddress.getByAddress(addr);
                     return