connect to closer nodes for introset lookups

llarp/dht/messages/findintro.cpp

@@ -2,6 +2,8 @@
 #include <dht/messages/findintro.hpp>
 #include <dht/messages/gotintro.hpp>
 #include <routing/message.hpp>
+#include <router/abstractrouter.hpp>
+#include <nodedb.hpp>
 
 namespace llarp
 {
@@ -112,8 +114,14 @@ namespace llarp
         Key_t us     = dht.OurKey();
         Key_t target = S.ToKey();
         // we are recursive
-        if(dht.Nodes()->FindCloseExcluding(target, peer, exclude))
+        const auto rc = dht.GetRouter()->nodedb()->FindClosestTo(target);
         {
+          peer = Key_t(rc.pubkey);
+          if(peer == us)
+          {
+            replies.emplace_back(new GotIntroMessage({}, T));
+            return true;
+          }
           if(relayed)
             dht.LookupIntroSetForPath(S, T, pathID, peer, R - 1);
           else

llarp/nodedb.cpp

@@ -9,6 +9,7 @@
 #include <util/mem.hpp>
 #include <util/thread/logic.hpp>
 #include <util/thread/thread_pool.hpp>
+#include <dht/kademlia.hpp>
 
 #include <fstream>
 #include <unordered_map>
@@ -92,6 +93,25 @@ llarp_nodedb::Has(const llarp::RouterID &pk)
   return entries.find(pk) != entries.end();
 }
 
+llarp::RouterContact
+llarp_nodedb::FindClosestTo(const llarp::dht::Key_t &location)
+{
+  llarp::RouterContact rc;
+  const llarp::dht::XorMetric compare(location);
+  visit([&rc, compare](const auto &otherRC) -> bool {
+    if(rc.pubkey.IsZero())
+    {
+      rc = otherRC;
+      return true;
+    }
+    if(compare(llarp::dht::Key_t{otherRC.pubkey.as_array()},
+               llarp::dht::Key_t{rc.pubkey.as_array()}))
+      rc = otherRC;
+    return true;
+  });
+  return rc;
+}
+
 /// skiplist directory is hex encoded first nibble
 /// skiplist filename is <base32encoded>.snode.signed
 std::string

llarp/nodedb.hpp

@@ -6,6 +6,7 @@
 #include <util/common.hpp>
 #include <util/fs.hpp>
 #include <util/thread/threading.hpp>
+#include <dht/key.hpp>
 
 #include <absl/base/thread_annotations.h>
 
@@ -73,6 +74,9 @@ struct llarp_nodedb
   NetDBMap_t entries GUARDED_BY(access);
   fs::path nodePath;
 
+  llarp::RouterContact
+  FindClosestTo(const llarp::dht::Key_t &location);
+
   /// return true if we should save our nodedb to disk
   bool
   ShouldSaveToDisk(llarp_time_t now = 0) const;