From 0c64d208d9368fadd6d8911b49e5f322b970f9d4 Mon Sep 17 00:00:00 2001
From: Daniel Larimer <dlarimer@invictus-innovations.com>
Date: Wed, 11 Jun 2014 15:17:28 -0400
Subject: [PATCH] adding ntp support to fc

---
 CMakeLists.txt             |  4 ++++
 include/fc/crypto/hex.hpp  |  2 ++
 include/fc/network/ntp.hpp | 15 ++++++++++++++
 ntp_test.cpp               | 15 ++++++++++++++
 src/crypto/hex.cpp         |  6 ++++++
 src/network/ntp.cpp        | 42 ++++++++++++++++++++++++++++++++++++++
 6 files changed, 84 insertions(+)
 create mode 100644 include/fc/network/ntp.hpp
 create mode 100644 ntp_test.cpp
 create mode 100644 src/network/ntp.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0cba89e..0dc4d6a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -148,6 +148,7 @@ set( fc_sources
      src/network/udp_socket.cpp
      src/network/http/http_connection.cpp
      src/network/http/http_server.cpp
+     src/network/ntp.cpp
      src/network/ip.cpp
      src/network/rate_limiting.cpp
      src/network/resolve.cpp
@@ -214,6 +215,9 @@ target_include_directories(fc
 
 target_link_libraries( fc PUBLIC easylzma_static ${Boost_LIBRARIES} ${OPENSSL_LIBRARIES} ${ZLIB_LIBRARIES} ${CMAKE_DL_LIBS})
 
+add_executable( ntp_test ntp_test.cpp )
+target_link_libraries( ntp_test fc )
+
 #add_executable( test_compress tests/compress.cpp )
 #target_link_libraries( test_compress fc )
 #add_executable( test_aes tests/aes_test.cpp )
diff --git a/include/fc/crypto/hex.hpp b/include/fc/crypto/hex.hpp
index f3ca29e..201f167 100644
--- a/include/fc/crypto/hex.hpp
+++ b/include/fc/crypto/hex.hpp
@@ -1,10 +1,12 @@
 #pragma once
 #include <fc/string.hpp>
 #include <fc/utility.hpp>
+#include <vector>
 
 namespace fc {
     uint8_t from_hex( char c );
     fc::string to_hex( const char* d, uint32_t s );
+    std::string to_hex( const std::vector<char>& data );
 
     /**
      *  @return the number of bytes decoded
diff --git a/include/fc/network/ntp.hpp b/include/fc/network/ntp.hpp
new file mode 100644
index 0000000..96fb54f
--- /dev/null
+++ b/include/fc/network/ntp.hpp
@@ -0,0 +1,15 @@
+#pragma once
+#include <string>
+#include <fc/time.hpp>
+
+
+namespace fc {
+
+   class ntp 
+   {
+      public:
+         static void set_server( const std::string& hostname, uint16_t port = 123 );
+         static fc::time_point get_time();
+   };
+
+} // namespace fc
diff --git a/ntp_test.cpp b/ntp_test.cpp
new file mode 100644
index 0000000..fbea98b
--- /dev/null
+++ b/ntp_test.cpp
@@ -0,0 +1,15 @@
+#include <fc/network/ntp.hpp>
+#include <fc/log/logger.hpp>
+
+int main( int argc, char** argv )
+{
+   fc::time_point ntp_time = fc::ntp::get_time();
+   auto delta = ntp_time - fc::time_point::now();
+   auto minutes = delta.count() / 1000000 / 60;
+   auto hours = delta.count() / 1000000 / 60 / 60;
+   auto seconds = delta.count() / 1000000;
+   auto msec= delta.count() / 1000;
+
+   idump( (ntp_time)(delta)(msec)(seconds)(minutes)(hours) );
+   return 0;
+}
diff --git a/src/crypto/hex.cpp b/src/crypto/hex.cpp
index 41690fe..67ef919 100644
--- a/src/crypto/hex.cpp
+++ b/src/crypto/hex.cpp
@@ -39,5 +39,11 @@ namespace fc {
         }
         return out_pos - (uint8_t*)out_data;
     }
+    std::string to_hex( const std::vector<char>& data )
+    {
+       if( data.size() )
+          return to_hex( data.data(), data.size() );
+       return "";
+    }
 
 }
diff --git a/src/network/ntp.cpp b/src/network/ntp.cpp
new file mode 100644
index 0000000..7f9e347
--- /dev/null
+++ b/src/network/ntp.cpp
@@ -0,0 +1,42 @@
+#include <fc/network/ntp.hpp>
+#include <fc/network/udp_socket.hpp>
+#include <fc/network/resolve.hpp>
+#include <fc/network/ip.hpp>
+
+#include <array>
+
+namespace fc
+{
+  static fc::ip::endpoint ntp_server;
+
+
+  void ntp::set_server( const std::string& hostname, uint16_t port  )
+  {
+     auto eps = resolve( hostname, port );
+     if(  eps.size() )
+        ntp_server = eps.front();
+  }
+
+  fc::time_point ntp::get_time()
+  {
+     static bool init_ntp_server = [](){
+        set_server( "pool.ntp.org", 123 );
+        return true;
+     }();
+     (void)init_ntp_server;
+
+     udp_socket sock;
+     sock.open();
+
+     std::array<unsigned char, 48> send_buf { {010,0,0,0,0,0,0,0,0} };
+
+     sock.send_to( (const char*)send_buf.data(), send_buf.size(), ntp_server );
+
+     fc::ip::endpoint from;
+     std::array<unsigned long, 1024> recv_buf;
+     sock.receive_from( (char*)recv_buf.data(), recv_buf.size(), from );
+
+     return fc::time_point() + fc::seconds( ntohl((time_t)recv_buf[4]) - 2208988800U);
+  }
+
+}