- Handle IPv6 in too-close checks

router/java/src/net/i2p/router/transport/udp/EstablishmentManager.java

@@ -960,7 +960,7 @@ class EstablishmentManager {
                port <= 65535 &&
                ip != null && ip.length == 4 &&
                _transport.isValid(ip) &&
-               (!DataHelper.eq(ip, 0, _transport.getExternalIP(), 0, 2)) &&
+               (!_transport.isTooClose(ip)) &&
                (!_context.blocklist().isBlocklisted(ip));
     }
 

router/java/src/net/i2p/router/transport/udp/IntroductionManager.java

@@ -433,7 +433,7 @@ class IntroductionManager {
                port <= 65535 &&
                ip != null && ip.length == 4 &&
                _transport.isValid(ip) &&
-               (!DataHelper.eq(ip, 0, _transport.getExternalIP(), 0, 2)) &&
+               (!_transport.isTooClose(ip)) &&
                (!_context.blocklist().isBlocklisted(ip));
     }
 }

router/java/src/net/i2p/router/transport/udp/PacketBuilder.java

@@ -1084,7 +1084,7 @@ class PacketBuilder {
                 // must be IPv4 for now as we don't send Alice IP/port, see below
                 iaddr.getAddress().length != 4 ||
                 (!_transport.isValid(iaddr.getAddress())) ||
-                Arrays.equals(iaddr.getAddress(), _transport.getExternalIP())) {
+                (Arrays.equals(iaddr.getAddress(), _transport.getExternalIP()) && !_transport.allowLocal())) {
                 if (_log.shouldLog(_log.WARN))
                     _log.warn("Cannot build a relay request to " + state.getRemoteIdentity().calculateHash()
                                + ", as their UDP address is invalid: addr=" + addr + " index=" + i);

router/java/src/net/i2p/router/transport/udp/PeerTestManager.java

@@ -182,7 +182,7 @@ class PeerTestManager {
                 _log.warn("We are already running a test: " + _currentTest + ", aborting test with bob = " + bobIP);
             return;
         }
-        if (DataHelper.eq(bobIP.getAddress(), 0, _transport.getExternalIP(), 0, 2)) {
+        if (_transport.isTooClose(bobIP.getAddress())) {
             if (_log.shouldLog(Log.WARN))
                 _log.warn("Not running test with Bob too close to us " + bobIP);
             return;
@@ -496,7 +496,7 @@ class PeerTestManager {
         int fromPort = from.getPort();
         if (fromPort < 1024 || fromPort > 65535 ||
             (!_transport.isValid(fromIP)) ||
-            DataHelper.eq(fromIP, 0, _transport.getExternalIP(), 0, 2) ||
+            _transport.isTooClose(fromIP) ||
             _context.blocklist().isBlocklisted(fromIP)) {
             // spoof check, and don't respond to privileged ports
             if (_log.shouldLog(Log.WARN))
@@ -556,7 +556,7 @@ class PeerTestManager {
         Long lNonce = Long.valueOf(nonce);
         PeerTestState state = _activeTests.get(lNonce);
 
-        if (testIP != null && DataHelper.eq(testIP, 0, _transport.getExternalIP(), 0, 2)) {
+        if (testIP != null && _transport.isTooClose(testIP)) {
             // spoof check - have to do this after receiveTestReply(), since
             // the field should be us there.
             // Let's also eliminate anybody in the same /16

router/java/src/net/i2p/router/transport/udp/UDPPacket.java

@@ -10,6 +10,7 @@ import net.i2p.I2PAppContext;
 import net.i2p.data.DataHelper;
 import net.i2p.data.SessionKey;
 import net.i2p.router.util.CDQEntry;
+import net.i2p.util.Addresses;
 import net.i2p.util.Log;
 
 /**
@@ -292,8 +293,7 @@ class UDPPacket implements CDQEntry {
         StringBuilder buf = new StringBuilder(256);
         buf.append(_packet.getLength());
         buf.append(" byte pkt with ");
-        buf.append(_packet.getAddress().getHostAddress()).append(":");
-        buf.append(_packet.getPort());
+        buf.append(Addresses.toString(_packet.getAddress().getAddress(), _packet.getPort()));
         //buf.append(" id=").append(System.identityHashCode(this));
         if (_messageType >= 0)
             buf.append(" msgType=").append(_messageType);

router/java/src/net/i2p/router/transport/udp/UDPTransport.java

@@ -508,6 +508,30 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
         return null;
     }
 
+    /**
+     *  Is this IP too close to ours to trust it for
+     *  things like relaying?
+     *  @param ip IPv4 or IPv6
+     *  @since IPv6
+     */
+    boolean isTooClose(byte[] ip) {
+        if (allowLocal())
+            return false;
+        for (RouterAddress addr : getCurrentAddresses()) {
+            byte[] myip = addr.getIP();
+            if (myip == null || ip.length != myip.length)
+                continue;
+            if (ip.length == 4) {
+                if (DataHelper.eq(ip, 0, myip, 0, 2))
+                    return true;
+            } else if (ip.length == 16) {
+                if (DataHelper.eq(ip, 0, myip, 0, 8))
+                    return true;
+            }
+        }
+        return false;
+    }
+
     /**
      *  The current port of the first matching endpoint.
      *  To be enhanced to handle multiple endpoints of the same type.
@@ -2980,7 +3004,7 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
             }
             if (ip == null)
                 continue;
-            if (DataHelper.eq(ip, 0, getExternalIP(), 0, 2))
+            if (isTooClose(ip))
                 continue;
             return peer;
         }