Gives seednode priority over dnsseed if both are provided

src/net.cpp

@@ -2172,7 +2172,30 @@ void CConnman::ThreadDNSAddressSeed()
     std::vector<std::string> seeds = m_params.DNSSeeds();
     Shuffle(seeds.begin(), seeds.end(), rng);
     int seeds_right_now = 0; // Number of seeds left before testing if we have enough connections
-    int found = 0;
+    int target_outbound_connections = 2;
+    int outbound_connection_count = 0;
+
+    auto start = NodeClock::now();
+    if (gArgs.IsArgSet("-seednode")) {
+        LogPrintf("-seednode enabled. Trying the provided seeds before defaulting to the dnsseeds.\n");
+        while (!interruptNet) {
+            if (!interruptNet.sleep_for(std::chrono::milliseconds(500)))
+                return;
+
+            // Abort if we have spent enough time without reaching our target.
+            // Giving seed nodes 30 seconds so this does not become a race against fixedseeds (which triggers after 1 min)
+            if (NodeClock::now() > start + 30s) {
+                LogPrintf("Couldn't connect to enough peers via seed nodes. Handing fetch logic to the DNS seeds.\n");
+                break;
+            }
+
+            outbound_connection_count = GetFullOutboundConnCount();
+            if (outbound_connection_count >= target_outbound_connections) {
+                    LogPrintf("P2P peers available. Finished fetching data from seed nodes.\n");
+                break;
+            }
+        }
+    }
 
     if (gArgs.GetBoolArg("-forcednsseed", DEFAULT_FORCEDNSSEED)) {
         // When -forcednsseed is provided, query all.
@@ -2184,6 +2207,8 @@ void CConnman::ThreadDNSAddressSeed()
         seeds_right_now = seeds.size();
     }
 
+    // Proceed with dnsseeds if seednodes hasn't reached the target or if forcednsseed is set
+    if (outbound_connection_count < target_outbound_connections || seeds_right_now) {
         // goal: only query DNS seed if address need is acute
         // * If we have a reasonable number of peers in addrman, spend
         //   some time trying them first. This improves user privacy by
@@ -2196,6 +2221,7 @@ void CConnman::ThreadDNSAddressSeed()
         // * If we continue having problems, eventually query all the
         //   DNS seeds, and if that fails too, also try the fixed seeds.
         //   (done in ThreadOpenConnections)
+        int found = 0;
         const std::chrono::seconds seeds_wait_time = (addrman.Size() >= DNSSEEDS_DELAY_PEER_THRESHOLD ? DNSSEEDS_DELAY_MANY_PEERS : DNSSEEDS_DELAY_FEW_PEERS);
 
         for (const std::string& seed : seeds) {
@@ -2213,14 +2239,7 @@ void CConnman::ThreadDNSAddressSeed()
                         if (!interruptNet.sleep_for(w)) return;
                         to_wait -= w;
 
-                    int nRelevant = 0;
-                    {
-                        LOCK(m_nodes_mutex);
-                        for (const CNode* pnode : m_nodes) {
-                            if (pnode->fSuccessfullyConnected && pnode->IsFullOutboundConn()) ++nRelevant;
-                        }
-                    }
-                    if (nRelevant >= 2) {
+                        if (GetFullOutboundConnCount() >= target_outbound_connections) {
                             if (found > 0) {
                                 LogPrintf("%d addresses found from DNS seeds\n", found);
                                 LogPrintf("P2P peers available. Finished DNS seeding.\n");
@@ -2280,6 +2299,9 @@ void CConnman::ThreadDNSAddressSeed()
             --seeds_right_now;
         }
         LogPrintf("%d addresses found from DNS seeds\n", found);
+    } else {
+        LogPrintf("Skipping DNS seeds. Enough peers have been found\n");
+    }
 }
 
 void CConnman::DumpAddresses()
@@ -2330,6 +2352,19 @@ void CConnman::StartExtraBlockRelayPeers()
     m_start_extra_block_relay_peers = true;
 }
 
+// Return the number of outbound connections that are full relay (not blocks only)
+int CConnman::GetFullOutboundConnCount() const
+{
+    int nRelevant = 0;
+    {
+        LOCK(m_nodes_mutex);
+        for (const CNode* pnode : m_nodes) {
+            if (pnode->fSuccessfullyConnected && pnode->IsFullOutboundConn()) ++nRelevant;
+        }
+    }
+    return nRelevant;
+}
+
 // Return the number of peers we have over our outbound connection limit
 // Exclude peers that are marked for disconnect, or are going to be
 // disconnected soon (eg ADDR_FETCH and FEELER)

src/net.h

@@ -1175,6 +1175,8 @@ public:
 
     void StartExtraBlockRelayPeers();
 
+    // Count the number of full-relay peer we have.
+    int GetFullOutboundConnCount() const;
     // Return the number of outbound peers we have in excess of our target (eg,
     // if we previously called SetTryNewOutboundPeer(true), and have since set
     // to false, we may have extra peers that we wish to disconnect). This may