* UDP: Bid lower than NTCP when we need introducers and don't

have enough; was preventing firewalled routers from
      being reachable

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

@@ -23,9 +23,9 @@ public class IntroductionManager {
     private UDPTransport _transport;
     private PacketBuilder _builder;
     /** map of relay tag to PeerState that should receive the introduction */
-    private Map _outbound;
+    private Map<Long, PeerState> _outbound;
     /** list of peers (PeerState) who have given us introduction tags */
-    private final List _inbound;
+    private final List<PeerState> _inbound;
 
     public IntroductionManager(RouterContext ctx, UDPTransport transport) {
         _context = ctx;
@@ -74,7 +74,7 @@ public class IntroductionManager {
     }
     
     public PeerState get(long id) {
-        return (PeerState)_outbound.get(new Long(id));
+        return _outbound.get(new Long(id));
     }
     
     /**
@@ -90,7 +90,7 @@ public class IntroductionManager {
      * and we want to keep our introducers valid.
      */
     public int pickInbound(Properties ssuOptions, int howMany) {
-        List peers = null;
+        List<PeerState> peers = null;
         int start = _context.random().nextInt(Integer.MAX_VALUE);
         synchronized (_inbound) {
             if (_log.shouldLog(Log.DEBUG))
@@ -103,7 +103,7 @@ public class IntroductionManager {
         int found = 0;
         long inactivityCutoff = _context.clock().now() - (UDPTransport.EXPIRE_TIMEOUT / 2);
         for (int i = 0; i < sz && found < howMany; i++) {
-            PeerState cur = (PeerState)peers.get((start + i) % sz);
+            PeerState cur = peers.get((start + i) % sz);
             RouterInfo ri = _context.netDb().lookupRouterInfoLocally(cur.getRemotePeer());
             if (ri == null) {
                 if (_log.shouldLog(Log.INFO))
@@ -144,7 +144,7 @@ public class IntroductionManager {
         long pingCutoff = _context.clock().now() - (2 * 60 * 60 * 1000);
         inactivityCutoff = _context.clock().now() - (UDPTransport.EXPIRE_TIMEOUT / 4);
         for (int i = 0; i < sz; i++) {
-            PeerState cur = (PeerState)peers.get(i);
+            PeerState cur = peers.get(i);
             if (cur.getIntroducerTime() > pingCutoff &&
                 cur.getLastSendTime() < inactivityCutoff) {
                 if (_log.shouldLog(Log.INFO))
@@ -157,6 +157,18 @@ public class IntroductionManager {
         return found;
     }
     
+    /**
+     * Not as elaborate as pickInbound() above.
+     * Just a quick check to see how many volunteers we know,
+     * which the Transport uses to see if we need more.
+     * @return number of peers that have volunteerd to introduce us
+     */
+    int introducerCount() {
+        synchronized(_inbound) {
+            return _inbound.size();
+        }
+    }
+
     void receiveRelayIntro(RemoteHostId bob, UDPPacketReader reader) {
         if (_context.router().isHidden())
             return;

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

@@ -461,13 +461,15 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
         boolean updated = false;
         boolean fireTest = false;
 
+        if (_log.shouldLog(Log.WARN))
+            _log.warn("Change address? status = " + _reachabilityStatus +
+                      " diff = " + (_context.clock().now() - _reachabilityStatusLastUpdated) +
+                      " old = " + _externalListenHost + ':' + _externalListenPort +
+                      " new = " + DataHelper.toString(ourIP) + ':' + ourPort);
+
             synchronized (this) {
                 if ( (_externalListenHost == null) ||
                      (!eq(_externalListenHost.getAddress(), _externalListenPort, ourIP, ourPort)) ) {
-                    if (_log.shouldLog(Log.WARN))
-                        _log.warn("Change address? status = " + _reachabilityStatus +
-                                  " diff = " + (_context.clock().now() - _reachabilityStatusLastUpdated) +
-                                  " old = " + _externalListenHost + ':' + _externalListenPort);
                     if ( (_reachabilityStatus != CommSystemFacade.STATUS_OK) ||
                          (_externalListenHost == null) || (_externalListenPort <= 0) ||
                          (_context.clock().now() - _reachabilityStatusLastUpdated > 2*TEST_FREQUENCY) ) {
@@ -968,6 +970,11 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
         return _endpoint.send(packet); 
     }
     
+    /** minimum active peers to maintain IP detection, etc. */
+    private static final int MIN_PEERS = 3;
+    /** minimum peers volunteering to be introducers if we need that */
+    private static final int MIN_INTRODUCER_POOL = 4;
+
     public TransportBid bid(RouterInfo toAddress, long dataSize) {
         if (dataSize > OutboundMessageState.MAX_MSG_SIZE) {
             // NTCP max is lower, so msg will get dropped
@@ -1015,11 +1022,16 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
 
             // Try to maintain at least 3 peers so we can determine our IP address and
             // we have a selection to run peer tests with.
+            // If we are firewalled, and we don't have enough peers that volunteered to
+            // also introduce us, also bid aggressively so we are preferred over NTCP.
+            // (Otherwise we only talk UDP to those that are firewalled, and we will
+            // never get any introducers)
             int count;
             synchronized (_peersByIdent) {
                 count = _peersByIdent.size();
             }
-            if (alwaysPreferUDP() || count < 3)
+            if (alwaysPreferUDP() || count < MIN_PEERS ||
+                (introducersRequired() && _introManager.introducerCount() < MIN_INTRODUCER_POOL))
                 return _slowPreferredBid;
             else if (preferUDP())
                 return _slowBid;
@@ -1157,6 +1169,9 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
                     _log.info("Picked peers: " + found);
                 _introducersSelectedOn = _context.clock().now();
                 introducersIncluded = true;
+            } else {
+                if (_log.shouldLog(Log.WARN))
+                    _log.warn("Need introducers but we don't know any");
             }
         }