dht: allow search table update with listen token refresh

src/dht.cpp

@@ -661,8 +661,9 @@ Dht::searchSynchedNodeListen(const Sp<Search>& sr, SearchNode& n)
                 /* on new values */
                 if (auto sr = ws.lock()) {
                     scheduler.edit(sr->nextSearchStep, scheduler.time());
-                    sr->insertNode(node, scheduler.time(), answer.ntoken);
                     if (auto sn = sr->getNode(node)) {
+                        if (not answer.ntoken.empty())
+                            sn->refreshToken(answer.ntoken);
                         sn->onValues(query, std::move(answer), types, scheduler);
                     }
                 }
@@ -2715,7 +2716,9 @@ Dht::onListenDone(const Sp<Node>& node, net::RequestAnswer& answer, Sp<Search>&
 
     if (not sr->done) {
         const auto& now = scheduler.time();
-        sr->insertNode(node, now, answer.ntoken);
+        if (not answer.ntoken.empty())
+            if (auto sn = sr->getNode(node))
+                sn->refreshToken(answer.ntoken);
         searchSendGetValues(sr);
         scheduler.edit(sr->nextSearchStep, now);
     }

src/search.h

@@ -133,6 +133,16 @@ struct Dht::SearchNode
         return last_get_reply + Node::NODE_EXPIRE_TIME;
     }
 
+    /**
+     * Update the token without refreshing last_get_reply,
+     * so that periodic find_node/get requests still occur.
+     */
+    void refreshToken(const Blob& tok)
+    {
+        if (not tok.empty() and tok.size() <= 64)
+            token = tok;
+    }
+
     friend std::ostream& operator<<(std::ostream& s, const SearchNode& node)
     {
         s << "getStatus:" << node.getStatus.size() << " listenStatus:" << node.listenStatus.size()

tests/test_networkengine.cpp

@@ -428,8 +428,10 @@ NetworkEngineTester::testListenConfirmationUpdatesSearchNodeToken()
     localDht.onListenDone(node, answer, sr);
 
     CPPUNIT_ASSERT(searchNodePtr->token == answer.ntoken);
-    CPPUNIT_ASSERT(searchNodePtr->last_get_reply == localDht.scheduler.time());
-    CPPUNIT_ASSERT(searchNodePtr->isSynced(localDht.scheduler.time()));
+    /* last_get_reply should NOT be updated by listen confirmation,
+       so that periodic find_node requests still refresh the search table. */
+    CPPUNIT_ASSERT(searchNodePtr->last_get_reply == time_point::min());
+    CPPUNIT_ASSERT(!searchNodePtr->isSynced(localDht.scheduler.time()));
 }
 
 void