Full command forwarding (#75)

CMakeLists.txt

@@ -43,12 +43,6 @@ if(RECORD_TRACE)
   add_definitions(-DNO_COMMITTED_TX_HISTORY)
 endif()
 
-option(RPC_FORWARD_TO_LEADER "Followers verify signatures and forward RPC to leader" OFF)
-if (RPC_FORWARD_TO_LEADER)
-  add_definitions(-DRPC_FORWARD_TO_LEADER)
-  set(TEST_FORWARD_TO_LEADER "--leader-forwarding")
-endif()
-
 option(BUILD_SMALLBANK "Build SmallBank sample app and clients" ON)
 
 # MemberClient executable

src/apps/luageneric/luageneric_test.cpp

@@ -114,13 +114,15 @@ template <typename F, typename K, typename V>
 void check_store_load(F frontend, K k, V v)
 {
   const Cert u0 = {0};
+  enclave::RpcContext rpc_ctx(0, u0);
+
   // store
   const auto pc0 = make_pc("store", {{"k", k}, {"v", v}});
-  check_success(frontend->process(u0, pc0), true);
+  check_success(frontend->process(rpc_ctx, pc0), true);
 
   // load and check that we get the right result
   const auto pc1 = make_pc("load", {{"k", k}});
-  check_success(frontend->process(u0, pc1), v);
+  check_success(frontend->process(rpc_ctx, pc1), v);
 }
 
 TEST_CASE("simple lua apps")
@@ -130,6 +132,7 @@ TEST_CASE("simple lua apps")
   // create network with 1 user and 3 active members
   auto frontend = init_frontend(network, notifier, 1, 3);
   const Cert u0 = {0};
+  enclave::RpcContext rpc_ctx(0, u0);
 
   SUBCASE("echo")
   {
@@ -149,7 +152,7 @@ TEST_CASE("simple lua apps")
     // call "echo" function with "hello"
     const string verb = "hello";
     const auto pc = make_pc("echo", {{"verb", verb}});
-    check_success(frontend->process(u0, pc), verb);
+    check_success(frontend->process(rpc_ctx, pc), verb);
   }
 
   SUBCASE("store/load different types in generic table")
@@ -191,7 +194,7 @@ TEST_CASE("simple lua apps")
 
     // (3) attempt to read non-existing key (set of integers)
     const auto pc = make_pc("load", {{"k", set{5, 6, 7}}});
-    check_error(frontend->process(u0, pc), ErrorCodes::INVALID_PARAMS);
+    check_error(frontend->process(rpc_ctx, pc), ErrorCodes::INVALID_PARAMS);
   }
 
   SUBCASE("access gov tables")
@@ -223,12 +226,12 @@ TEST_CASE("simple lua apps")
     map<string, MemberInfo> expected = {{"0", {MemberStatus::ACTIVE}},
                                         {"1", {MemberStatus::ACTIVE}},
                                         {"2", {MemberStatus::ACTIVE}}};
-    check_success(frontend->process(u0, pc), expected);
+    check_success(frontend->process(rpc_ctx, pc), expected);
 
     // (2) try to write to members table
     const auto pc1 = make_pc(
       "put_member", {{"k", 99}, {"v", MemberInfo{MemberStatus::ACTIVE}}});
-    check_error(frontend->process(u0, pc1), ErrorCodes::SCRIPT_ERROR);
+    check_error(frontend->process(rpc_ctx, pc1), ErrorCodes::SCRIPT_ERROR);
   }
 }
 
@@ -239,6 +242,7 @@ TEST_CASE("simple bank")
   // create network with 1 user and 3 active members
   auto frontend = init_frontend(network, notifier, 1, 3);
   const Cert u0 = {0};
+  enclave::RpcContext rpc_ctx(0, u0);
 
   constexpr auto app = R"xxx(
   tables, gov_tables, caller_id, method, params = ...
@@ -293,34 +297,34 @@ TEST_CASE("simple bank")
 
   {
     const auto pc = make_pc("SB_create", {{"dst", 1}, {"amt", 123}});
-    check_success<string>(frontend->process(u0, pc), "OK");
+    check_success<string>(frontend->process(rpc_ctx, pc), "OK");
 
     const auto pc1 = make_pc("SB_read", {{"account", 1}});
-    check_success(frontend->process(u0, pc1), 123);
+    check_success(frontend->process(rpc_ctx, pc1), 123);
   }
 
   {
     const auto pc = make_pc("SB_create", {{"dst", 2}, {"amt", 999}});
-    check_success<string>(frontend->process(u0, pc), "OK");
+    check_success<string>(frontend->process(rpc_ctx, pc), "OK");
 
     const auto pc1 = make_pc("SB_read", {{"account", 2}});
-    check_success(frontend->process(u0, pc1), 999);
+    check_success(frontend->process(rpc_ctx, pc1), 999);
   }
 
   {
     const auto pc = make_pc("SB_read", {{"account", 3}});
-    check_error(frontend->process(u0, pc), ErrorCodes::INVALID_PARAMS);
+    check_error(frontend->process(rpc_ctx, pc), ErrorCodes::INVALID_PARAMS);
   }
 
   {
     const auto pc =
       make_pc("SB_transfer", {{"src", 1}, {"dst", 2}, {"amt", 5}});
-    check_success<string>(frontend->process(u0, pc), "OK");
+    check_success<string>(frontend->process(rpc_ctx, pc), "OK");
 
     const auto pc1 = make_pc("SB_read", {{"account", 1}});
-    check_success(frontend->process(u0, pc1), 123 - 5);
+    check_success(frontend->process(rpc_ctx, pc1), 123 - 5);
 
     const auto pc2 = make_pc("SB_read", {{"account", 2}});
-    check_success(frontend->process(u0, pc2), 999 + 5);
+    check_success(frontend->process(rpc_ctx, pc2), 999 + 5);
   }
 }

src/enclave/enclave.h

@@ -11,6 +11,7 @@
 #include "node/nodestate.h"
 #include "node/nodetypes.h"
 #include "node/notifier.h"
+#include "node/rpc/forwarder.h"
 #include "node/rpc/managementfrontend.h"
 #include "node/rpc/memberfrontend.h"
 #include "node/rpc/nodefrontend.h"
@@ -28,6 +29,7 @@ namespace enclave
     ccf::NetworkState network;
     ccf::NodeState node;
     std::shared_ptr<ccf::NodeToNode> n2n_channels;
+    std::shared_ptr<ccf::Forwarder> cmd_forwarder;
     ccf::Notifier notifier;
     std::shared_ptr<RpcMap> rpc_map;
     bool recover = false;
@@ -38,8 +40,9 @@ namespace enclave
       writer_factory(circuit, config->writer_config),
       rpcsessions(writer_factory),
       n2n_channels(std::make_shared<ccf::NodeToNode>(writer_factory)),
-      node(writer_factory, network, rpcsessions, notifier),
-      notifier(writer_factory)
+      node(writer_factory, network, rpcsessions),
+      notifier(writer_factory),
+      cmd_forwarder(std::make_shared<ccf::Forwarder>(rpcsessions, n2n_channels))
     {
       rpc_map = std::make_shared<RpcMap>();
       rpc_map->emplace(
@@ -62,14 +65,20 @@ namespace enclave
         frontend->set_sig_intervals(
           config->signature_intervals.sig_max_tx,
           config->signature_intervals.sig_max_ms);
-        frontend->set_n2n_channels(n2n_channels);
+
+        // TODO: All frontends should be able to forward to/be forwarded to.
+        if (r.first == ccf::Actors::USERS)
+        {
+          frontend->set_cmd_forwarder(cmd_forwarder);
+        }
       }
 
       logger::config::msg() = AdminMessage::log_msg;
       logger::config::writer() = writer_factory.create_writer_to_outside();
 
       node.initialize(config->raft_config, n2n_channels);
       rpcsessions.initialize(rpc_map);
+      cmd_forwarder->initialize(rpc_map);
     }
 
     bool create_node(
@@ -132,22 +141,17 @@ namespace enclave
 
         DISPATCHER_SET_MESSAGE_HANDLER(
           bp, ccf::node_inbound, [this](const uint8_t* data, size_t size) {
-            auto [body] =
+            const auto [body] =
               ringbuffer::read_message<ccf::node_inbound>(data, size);
 
-            const auto& body_ = body;
-            auto p = body_.data();
-            auto psize = body_.size();
+            auto p = body.data();
+            auto psize = body.size();
 
             if (
               serialized::peek<ccf::NodeMsgType>(p, psize) ==
               ccf::NodeMsgType::forwarded_msg)
             {
-              serialized::skip(p, psize, sizeof(ccf::NodeMsgType));
-              LOG_DEBUG << "RPC forwarded: " << ccf::Actors::USERS << std::endl;
-
-              rpc_map->at(std::string(ccf::Actors::USERS))
-                ->process_forwarded(p, psize);
+              cmd_forwarder->recv_message(p, psize);
             }
             else
             {

src/enclave/rpcendpoint.h

@@ -14,6 +14,7 @@ namespace enclave
   private:
     std::shared_ptr<RpcMap> rpc_map;
     std::shared_ptr<RpcHandler> handler;
+    size_t session_id;
     CBuffer caller;
 
   public:
@@ -23,7 +24,8 @@ namespace enclave
       ringbuffer::AbstractWriterFactory& writer_factory,
       std::unique_ptr<tls::Context> ctx) :
       FramedTLSEndpoint(session_id, writer_factory, move(ctx)),
-      rpc_map(rpc_map_)
+      rpc_map(rpc_map_),
+      session_id(session_id)
     {}
 
     bool handle_data(const std::vector<uint8_t>& data)
@@ -42,7 +44,22 @@ namespace enclave
         caller = peer_cert();
       }
 
-      send(handler->process(caller, data));
+      // Create a new RPC context for each command since some may require
+      // forwarding to the leader.
+      RpcContext rpc_ctx(session_id, caller);
+      auto rep = handler->process(rpc_ctx, data);
+
+      if (rpc_ctx.is_forwarded)
+      {
+        // If the RPC has been forwarded, hold the connection.
+        return true;
+      }
+      else
+      {
+        // Otherwise, reply to the client synchronously.
+        send(rep);
+      }
+
       return true;
     }
   };

src/enclave/rpchandler.h

@@ -1,24 +1,36 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the Apache 2.0 License.
 #pragma once
-#include "../ds/buffer.h"
+#include "ds/buffer.h"
 
 #include <chrono>
+#include <limits>
 #include <stdint.h>
 #include <vector>
 
 namespace enclave
 {
+  static constexpr size_t InvalidSessionId = std::numeric_limits<size_t>::max();
+
+  struct RpcContext
+  {
+    const size_t session_id;
+    const CBuffer caller;
+    bool is_forwarded = false;
+
+    RpcContext(size_t session_id_, CBuffer caller_) :
+      session_id(session_id_),
+      caller(caller_)
+    {}
+  };
+
   class RpcHandler
   {
   public:
     virtual ~RpcHandler() {}
 
     virtual std::vector<uint8_t> process(
-      CBuffer caller, const std::vector<uint8_t>& input) = 0;
-
-    virtual std::vector<uint8_t> process_forwarded(
-      const uint8_t* data, size_t size) = 0;
+      RpcContext& rpc_ctx, const std::vector<uint8_t>& input) = 0;
 
     virtual void tick(std::chrono::milliseconds elapsed_ms_count) {}
   };

src/enclave/rpcsessions.h

@@ -78,6 +78,20 @@ namespace enclave
       sessions.insert(std::make_pair(id, std::move(session)));
     }
 
+    void reply_forwarded(size_t id, const std::vector<uint8_t>& data)
+    {
+      std::lock_guard<SpinLock> guard(lock);
+
+      auto search = sessions.find(id);
+      if (search == sessions.end())
+      {
+        throw std::logic_error(
+          "reply forwarded for unknown session: " + std::to_string(id));
+      }
+
+      search->second->send(data);
+    }
+
     void remove_session(size_t id)
     {
       std::lock_guard<SpinLock> guard(lock);

src/enclave/tlsendpoint.h

@@ -153,8 +153,8 @@ namespace enclave
       // MBEDTLS_ERR_SSL_WANT_READ. Probably hit a size limit - try again
       if (exact && (total < up_to))
       {
-        LOG_INFO << "Asked for exactly " << up_to << ", received " << total
-                 << ", retrying" << std::endl;
+        LOG_DEBUG << "Asked for exactly " << up_to << ", received " << total
+                  << ", retrying" << std::endl;
         read_buffer = move(data);
         return read(up_to, exact);
       }

src/node/channels.h

@@ -112,7 +112,7 @@ namespace ccf
       const GcmHdr& header, CBuffer aad, CBuffer cipher, Buffer plain)
     {
       if (status != ESTABLISHED)
-        throw std::logic_error("Channel is not established for encrypting");
+        throw std::logic_error("Channel is not established for decrypting");
 
       return key->decrypt(header.getIv(), header.tag, cipher, aad, plain.p);
     }

src/node/nodestate.h

@@ -19,7 +19,6 @@
 #include "kv/replicator.h"
 #include "networkstate.h"
 #include "nodetonode.h"
-#include "notifier.h"
 #include "rpc/consts.h"
 #include "rpc/frontend.h"
 #include "rpc/serialization.h"
@@ -126,7 +125,6 @@ namespace ccf
     enclave::RPCSessions& rpcsessions;
     std::shared_ptr<kv::TxHistory> history;
     std::shared_ptr<kv::AbstractTxEncryptor> encryptor;
-    Notifier& notifier;
 
     //
     // join protocol
@@ -160,15 +158,13 @@ namespace ccf
     NodeState(
       ringbuffer::AbstractWriterFactory& writer_factory,
       NetworkState& network,
-      enclave::RPCSessions& rpcsessions,
-      Notifier& notifier) :
+      enclave::RPCSessions& rpcsessions) :
       sm(State::uninitialized),
       self(INVALID_ID),
       writer_factory(writer_factory),
       to_host(writer_factory.create_writer_to_outside()),
       network(network),
-      rpcsessions(rpcsessions),
-      notifier(notifier)
+      rpcsessions(rpcsessions)
     {
       ::EverCrypt_AutoConfig2_init();
     }
@@ -880,14 +876,14 @@ namespace ccf
 #endif
     }
 
-    bool node_msg(const std::vector<uint8_t>& data)
+    void node_msg(const std::vector<uint8_t>& data)
     {
       // Only process messages once part of network
       if (
         !sm.check(State::partOfNetwork) &&
         !sm.check(State::partOfPublicNetwork))
       {
-        return false;
+        return;
       }
 
       auto p = data.data();
@@ -912,7 +908,6 @@ namespace ccf
         default:
         {}
       }
-      return true;
     }
 
     bool pbft_msg(const uint8_t* data, size_t size)