From 42a7a4dd320f002457843b4418314f43a70c0c8f Mon Sep 17 00:00:00 2001
From: xiphon <xiphon@protonmail.com>
Date: Wed, 26 Feb 2020 12:37:28 +0000
Subject: daemon: auto public nodes - cache and prioritize most stable nodes

---
 src/rpc/core_rpc_server.cpp | 50 ++++++++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 23 deletions(-)

(limited to 'src/rpc/core_rpc_server.cpp')

diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index e92ae7c08..eaded5726 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -170,7 +170,7 @@ namespace cryptonote
     return set_bootstrap_daemon(address, credentials);
   }
   //------------------------------------------------------------------------------------------------------------------------------
-  boost::optional<std::string> core_rpc_server::get_random_public_node()
+  std::map<std::string, bool> core_rpc_server::get_public_nodes(uint32_t credits_per_hash_threshold/* = 0*/)
   {
     COMMAND_RPC_GET_PUBLIC_NODES::request request;
     COMMAND_RPC_GET_PUBLIC_NODES::response response;
@@ -179,47 +179,51 @@ namespace cryptonote
     request.white = true;
     if (!on_get_public_nodes(request, response) || response.status != CORE_RPC_STATUS_OK)
     {
-      return boost::none;
+      return {};
     }
 
-    const auto get_random_node_address = [](const std::vector<public_node>& public_nodes) -> std::string {
-      const auto& random_node = public_nodes[crypto::rand_idx(public_nodes.size())];
-      const auto address = random_node.host + ":" + std::to_string(random_node.rpc_port);
-      return address;
-    };
-
-    if (!response.white.empty())
-    {
-      return get_random_node_address(response.white);
-    }
+    std::map<std::string, bool> result;
 
-    MDEBUG("No white public node found, checking gray peers");
-
-    if (!response.gray.empty())
-    {
-      return get_random_node_address(response.gray);
-    }
+    const auto append = [&result, &credits_per_hash_threshold](const std::vector<public_node> &nodes, bool white) {
+      for (const auto &node : nodes)
+      {
+        const bool rpc_payment_enabled = credits_per_hash_threshold > 0;
+        const bool node_rpc_payment_enabled = node.rpc_credits_per_hash > 0;
+        if (!node_rpc_payment_enabled ||
+            (rpc_payment_enabled && node.rpc_credits_per_hash >= credits_per_hash_threshold))
+        {
+          result.insert(std::make_pair(node.host + ":" + std::to_string(node.rpc_port), white));
+        }
+      }
+    };
 
-    MERROR("Failed to find any suitable public node");
+    append(response.white, true);
+    append(response.gray, false);
 
-    return boost::none;
+    return result;
   }
   //------------------------------------------------------------------------------------------------------------------------------
   bool core_rpc_server::set_bootstrap_daemon(const std::string &address, const boost::optional<epee::net_utils::http::login> &credentials)
   {
     boost::unique_lock<boost::shared_mutex> lock(m_bootstrap_daemon_mutex);
 
+    constexpr const uint32_t credits_per_hash_threshold = 0;
+    constexpr const bool rpc_payment_enabled = credits_per_hash_threshold != 0;
+
     if (address.empty())
     {
       m_bootstrap_daemon.reset(nullptr);
     }
     else if (address == "auto")
     {
-      m_bootstrap_daemon.reset(new bootstrap_daemon([this]{ return get_random_public_node(); }));
+      auto get_nodes = [this, credits_per_hash_threshold]() {
+        return get_public_nodes(credits_per_hash_threshold);
+      };
+      m_bootstrap_daemon.reset(new bootstrap_daemon(std::move(get_nodes), rpc_payment_enabled));
     }
     else
     {
-      m_bootstrap_daemon.reset(new bootstrap_daemon(address, credentials));
+      m_bootstrap_daemon.reset(new bootstrap_daemon(address, credentials, rpc_payment_enabled));
     }
 
     m_should_use_bootstrap_daemon = m_bootstrap_daemon.get() != nullptr;
@@ -1931,7 +1935,7 @@ namespace cryptonote
       if (*bootstrap_daemon_height < target_height)
       {
         MINFO("Bootstrap daemon is out of sync");
-        return m_bootstrap_daemon->handle_result(false);
+        return m_bootstrap_daemon->handle_result(false, {});
       }
 
       uint64_t top_height = m_core.get_current_blockchain_height();
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