From 916c52280983a96a792984ccb487908e91309bef Mon Sep 17 00:00:00 2001
From: Kevin Heifner <heifnerk@objectcomputing.com>
Date: Mon, 18 Mar 2019 10:25:56 -0500
Subject: [PATCH 1/2] Add strand to protect internals of asio

---
 plugins/net_plugin/net_plugin.cpp | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/plugins/net_plugin/net_plugin.cpp b/plugins/net_plugin/net_plugin.cpp
index 91ff34f00d5..736052dcca1 100644
--- a/plugins/net_plugin/net_plugin.cpp
+++ b/plugins/net_plugin/net_plugin.cpp
@@ -497,7 +497,8 @@ namespace eosio {
       transaction_state_index trx_state;
       optional<sync_state>    peer_requested;  // this peer is requesting info from us
       std::shared_ptr<boost::asio::io_context>  server_ioc; // keep ioc alive
-      socket_ptr              socket;
+      boost::asio::io_context::strand           strand;
+      socket_ptr                                socket;
 
       fc::message_buffer<1024*1024>    pending_message_buffer;
       fc::optional<std::size_t>        outstanding_read_bytes;
@@ -730,6 +731,7 @@ namespace eosio {
         trx_state(),
         peer_requested(),
         server_ioc( my_impl->server_ioc ),
+        strand( *my_impl->server_ioc ),
         socket( std::make_shared<tcp::socket>( std::ref( *my_impl->server_ioc ))),
         node_id(),
         last_handshake_recv(),
@@ -755,6 +757,7 @@ namespace eosio {
         trx_state(),
         peer_requested(),
         server_ioc( my_impl->server_ioc ),
+        strand( *my_impl->server_ioc ),
         socket( s ),
         node_id(),
         last_handshake_recv(),
@@ -976,7 +979,8 @@ namespace eosio {
       std::vector<boost::asio::const_buffer> bufs;
       buffer_queue.fill_out_buffer( bufs );
 
-      boost::asio::async_write(*socket, bufs, [c, priority]( boost::system::error_code ec, std::size_t w ) {
+      boost::asio::async_write(*socket, bufs,
+            boost::asio::bind_executor(strand, [c, priority]( boost::system::error_code ec, std::size_t w ) {
          app().post(priority, [c, priority, ec, w]() {
             try {
                auto conn = c.lock();
@@ -1016,7 +1020,7 @@ namespace eosio {
                fc_elog( logger,"Exception in do_queue_write to ${p}", ("p",pname) );
             }
          });
-      });
+      }));
    }
 
    void connection::cancel_sync(go_away_reason reason) {
@@ -1849,7 +1853,7 @@ namespace eosio {
       connection_wptr weak_conn = c;
       // Note: need to add support for IPv6 too
 
-      resolver->async_resolve( query,
+      resolver->async_resolve( query, boost::asio::bind_executor( c->strand,
                 [weak_conn, this]( const boost::system::error_code& err, tcp::resolver::iterator endpoint_itr ) {
                    app().post( priority::low, [err, endpoint_itr, weak_conn, this]() {
                       auto c = weak_conn.lock();
@@ -1861,7 +1865,7 @@ namespace eosio {
                                   ("peer_addr", c->peer_name())( "error", err.message()) );
                       }
                    } );
-                } );
+                } ) );
    }
 
    void net_plugin_impl::connect(const connection_ptr& c, tcp::resolver::iterator endpoint_itr) {
@@ -1873,7 +1877,8 @@ namespace eosio {
       ++endpoint_itr;
       c->connecting = true;
       connection_wptr weak_conn = c;
-      c->socket->async_connect( current_endpoint, [weak_conn, endpoint_itr, this]( const boost::system::error_code& err ) {
+      c->socket->async_connect( current_endpoint, boost::asio::bind_executor( c->strand,
+            [weak_conn, endpoint_itr, this]( const boost::system::error_code& err ) {
          app().post( priority::low, [weak_conn, endpoint_itr, this, err]() {
             auto c = weak_conn.lock();
             if( !c ) return;
@@ -1892,7 +1897,7 @@ namespace eosio {
                }
             }
          } );
-      } );
+      } ) );
    }
 
    bool net_plugin_impl::start_session(const connection_ptr& con) {
@@ -2042,6 +2047,7 @@ namespace eosio {
          ++conn->reads_in_flight;
          boost::asio::async_read(*conn->socket,
             conn->pending_message_buffer.get_buffer_sequence_for_boost_async_read(), completion_handler,
+            boost::asio::bind_executor( conn->strand,
             [this,weak_conn]( boost::system::error_code ec, std::size_t bytes_transferred ) {
             app().post( priority::medium, [this,weak_conn, ec, bytes_transferred]() {
                auto conn = weak_conn.lock();
@@ -2124,7 +2130,7 @@ namespace eosio {
                   close( conn );
                }
             });
-         });
+         }));
       } catch (...) {
          string pname = conn ? conn->peer_name() : "no connection name";
          fc_elog( logger, "Undefined exception handling reading ${p}",("p",pname) );

From 9e849da81b42fb292f5b3d1ad2b576ab9fbd3788 Mon Sep 17 00:00:00 2001
From: Kevin Heifner <heifnerk@objectcomputing.com>
Date: Tue, 19 Mar 2019 15:52:04 -0500
Subject: [PATCH 2/2] Ensure that intermediate asio operations are on the same
 thread

---
 plugins/net_plugin/net_plugin.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/plugins/net_plugin/net_plugin.cpp b/plugins/net_plugin/net_plugin.cpp
index 736052dcca1..521f36ca66c 100644
--- a/plugins/net_plugin/net_plugin.cpp
+++ b/plugins/net_plugin/net_plugin.cpp
@@ -731,7 +731,7 @@ namespace eosio {
         trx_state(),
         peer_requested(),
         server_ioc( my_impl->server_ioc ),
-        strand( *my_impl->server_ioc ),
+        strand( app().get_io_service() ),
         socket( std::make_shared<tcp::socket>( std::ref( *my_impl->server_ioc ))),
         node_id(),
         last_handshake_recv(),
@@ -757,7 +757,7 @@ namespace eosio {
         trx_state(),
         peer_requested(),
         server_ioc( my_impl->server_ioc ),
-        strand( *my_impl->server_ioc ),
+        strand( app().get_io_service() ),
         socket( s ),
         node_id(),
         last_handshake_recv(),