on path timeout look up each router, if the lookup fails then we remove it from nodedb and close any connections to it so that bad first hops are rotated off of.

llarp/path/pathbuilder.cpp

@@ -6,8 +6,10 @@
 #include "path_context.hpp"
 #include <llarp/profiling.hpp>
 #include <llarp/router/abstractrouter.hpp>
+#include <llarp/router/i_rc_lookup_handler.hpp>
 #include <llarp/util/buffer.hpp>
 #include <llarp/tooling/path_event.hpp>
+#include <llarp/link/link_manager.hpp>
 
 #include <functional>
 
@@ -477,16 +479,30 @@ namespace llarp
       m_router->routerProfiling().MarkPathTimeout(p.get());
       PathSet::HandlePathBuildTimeout(p);
       DoPathBuildBackoff();
-      bool firstHop = true;
       for (const auto& hop : p->hops)
       {
-        if (not firstHop)
-        {
-          RouterID router{hop.rc.pubkey};
-          LogWarn(Name(), " removing router ", router, " because of path build timeout");
-          m_router->nodedb()->Remove(router);
-        }
-        firstHop = false;
+        const RouterID router{hop.rc.pubkey};
+        // look up router and see if it's still on the network
+        m_router->loop()->call_soon([router, r = m_router]() {
+          LogInfo("looking up ", router, " because of path build timeout");
+          r->rcLookupHandler().GetRC(
+              router,
+              [r](const auto& router, const auto* rc, auto result) {
+                if (result == RCRequestResult::Success && rc != nullptr)
+                {
+                  LogInfo("refreshed rc for ", router);
+                  r->nodedb()->PutIfNewer(*rc);
+                }
+                else
+                {
+                  // remove all connections to this router as it's probably not registered anymore
+                  LogWarn("removing router ", router, " because of path build timeout");
+                  r->linkManager().DeregisterPeer(router);
+                  r->nodedb()->Remove(router);
+                }
+              },
+              true);
+        });
       }
     }