Enforce restricted # pool txs served via RPC + optimize chunked reqs [release-v0.18]

- `/getblocks.bin` respects the `RESTRICTED_TX_COUNT` (=100) when
returning pool txs via a restricted RPC daemon.
- A restricted RPC daemon includes a max of `RESTRICTED_TX_COUNT` txs
in the `added_pool_txs` field, and returns any remaining pool hashes
in the `remaining_added_pool_txids` field. The client then requests
the remaining txs via `/gettransactions` in chunks.
- `/gettransactions` no longer does expensive no-ops for ALL pool txs
if the client requests a subset of pool txs. Instead it searches for
the txs the client explicitly requests.
- Reset `m_pool_info_query_time` when a user:
  (1) rescans the chain (so the wallet re-requests the whole pool)
  (2) changes the daemon their wallets points to (a new daemon would
      have a different view of the pool)
- `/getblocks.bin` respects the `req.prune` field when returning
pool txs.
- Pool extension fields in response to `/getblocks.bin` are optional
with default 0'd values.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/wallet/node_rpc_proxy.cpp b/src/wallet/node_rpc_proxy.cpp
index 44c52df62..aa0b4dfd3 100644
--- a/src/wallet/node_rpc_proxy.cpp
+++ b/src/wallet/node_rpc_proxy.cpp
@@ -392,6 +392,36 @@ boost::optional<std::string> NodeRPCProxy::get_rpc_payment_info(bool mining, boo
   return boost::none;
 }
 
+boost::optional<std::string> NodeRPCProxy::get_transactions(const std::vector<crypto::hash> &txids, const std::function<void(const cryptonote::COMMAND_RPC_GET_TRANSACTIONS::request&, const cryptonote::COMMAND_RPC_GET_TRANSACTIONS::response&, bool)> &f)
+{
+  const size_t SLICE_SIZE = 100; // RESTRICTED_TRANSACTIONS_COUNT as defined in rpc/core_rpc_server.cpp
+  for (size_t offset = 0; offset < txids.size(); offset += SLICE_SIZE)
+  {
+    cryptonote::COMMAND_RPC_GET_TRANSACTIONS::request req_t = AUTO_VAL_INIT(req_t);
+    cryptonote::COMMAND_RPC_GET_TRANSACTIONS::response resp_t = AUTO_VAL_INIT(resp_t);
+
+    const size_t n_txids = std::min<size_t>(SLICE_SIZE, txids.size() - offset);
+    for (size_t n = offset; n < (offset + n_txids); ++n)
+      req_t.txs_hashes.push_back(epee::string_tools::pod_to_hex(txids[n]));
+    MDEBUG("asking for " << req_t.txs_hashes.size() << " transactions");
+    req_t.decode_as_json = false;
+    req_t.prune = true;
+
+    bool r = false;
+    {
+      const boost::lock_guard<boost::recursive_mutex> lock{m_daemon_rpc_mutex};
+      uint64_t pre_call_credits = m_rpc_payment_state.credits;
+      req_t.client = cryptonote::make_rpc_payment_signature(m_client_id_secret_key);
+      r = net_utils::invoke_http_json("/gettransactions", req_t, resp_t, m_http_client, rpc_timeout);
+      if (r && resp_t.status == CORE_RPC_STATUS_OK)
+        check_rpc_cost(m_rpc_payment_state, "/gettransactions", resp_t.credits, pre_call_credits, resp_t.txs.size() * COST_PER_TX);
+    }
+
+    f(req_t, resp_t, r);
+  }
+  return boost::optional<std::string>();
+}
+
 boost::optional<std::string> NodeRPCProxy::get_block_header_by_height(uint64_t height, cryptonote::block_header_response &block_header)
 {
   if (m_offline)