From 86cced792bd7e16a08b6185187083cc7024ed87d Mon Sep 17 00:00:00 2001
From: Alexey Rybalchenko <alexryba@gmail.com>
Date: Thu, 3 May 2018 15:00:32 +0200
Subject: [PATCH] Add resolver for hostname -> ip, use it before bind/connect

---
 fairmq/FairMQChannel.cxx |  6 ++---
 fairmq/FairMQDevice.cxx  | 27 ++++++++++++++++----
 fairmq/FairMQDevice.h    |  4 +--
 fairmq/tools/Network.h   | 55 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 82 insertions(+), 10 deletions(-)

diff --git a/fairmq/FairMQChannel.cxx b/fairmq/FairMQChannel.cxx
index c50332ad..e72e4903 100644
--- a/fairmq/FairMQChannel.cxx
+++ b/fairmq/FairMQChannel.cxx
@@ -12,12 +12,12 @@
  * @author A. Rybalchenko
  */
 
-#include <set>
-#include <utility> // std::move
+#include "FairMQChannel.h"
 
 #include <boost/algorithm/string.hpp> // join/split
 
-#include "FairMQChannel.h"
+#include <set>
+#include <utility> // std::move
 
 using namespace std;
 
diff --git a/fairmq/FairMQDevice.cxx b/fairmq/FairMQDevice.cxx
index 50ed5fd0..5443cc56 100644
--- a/fairmq/FairMQDevice.cxx
+++ b/fairmq/FairMQDevice.cxx
@@ -302,15 +302,32 @@ bool FairMQDevice::AttachChannel(FairMQChannel& ch)
             address = endpoint.substr(1);
         }
 
-        bool rc = true;
+        if (address.compare(0, 6, "tcp://") == 0)
+        {
+            string addressString = address.substr(6);
+            auto pos = addressString.find(":");
+            string hostPart = addressString.substr(0, pos);
+            if (!(bind && hostPart == "*"))
+            {
+                string portPart = addressString.substr(pos + 1);
+                string resolvedHost = fair::mq::tools::getIpFromHostname(hostPart);
+                if (resolvedHost == "")
+                {
+                    return false;
+                }
+                address.assign("tcp://" + resolvedHost + ":" + portPart);
+            }
+        }
+
+        bool success = true;
         // make the connection
         if (bind)
         {
-            rc = BindEndpoint(*ch.fSocket, address);
+            success = BindEndpoint(*ch.fSocket, address);
         }
         else
         {
-            rc = ConnectEndpoint(*ch.fSocket, address);
+            success = ConnectEndpoint(*ch.fSocket, address);
         }
 
         // bind might bind to an address different than requested,
@@ -325,9 +342,9 @@ bool FairMQDevice::AttachChannel(FairMQChannel& ch)
         LOG(debug) << "Attached channel " << ch.fName << " to " << endpoint << (bind ? " (bind) " : " (connect) ");
 
         // after the book keeping is done, exit in case of errors
-        if (!rc)
+        if (!success)
         {
-            return rc;
+            return success;
         }
     }
 
diff --git a/fairmq/FairMQDevice.h b/fairmq/FairMQDevice.h
index d4acae7d..6b2bdaae 100644
--- a/fairmq/FairMQDevice.h
+++ b/fairmq/FairMQDevice.h
@@ -530,8 +530,8 @@ class FairMQDevice : public FairMQStateMachine
     bool fExternalConfig;
 
     const fair::mq::tools::Version fVersion;
-    float fRate;
-    size_t fLastTime;
+    float fRate; ///< Rate limiting for ConditionalRun
+    size_t fLastTime; ///< Rate limiting for ConditionalRun
 };
 
 #endif /* FAIRMQDEVICE_H_ */
diff --git a/fairmq/tools/Network.h b/fairmq/tools/Network.h
index 4d35f297..9cd7514b 100644
--- a/fairmq/tools/Network.h
+++ b/fairmq/tools/Network.h
@@ -22,11 +22,13 @@
 #include <stdio.h>
 
 #include <boost/algorithm/string.hpp> // trim
+#include <boost/asio.hpp>
 
 #include <map>
 #include <string>
 #include <iostream>
 #include <array>
+#include <exception>
 
 namespace fair
 {
@@ -128,6 +130,59 @@ inline std::string getDefaultRouteNetworkInterface()
     return interfaceName;
 }
 
+inline std::string getIpFromHostname(const std::string& hostname)
+{
+    try {
+        boost::asio::io_service ios;
+        boost::asio::ip::tcp::resolver resolver(ios);
+        boost::asio::ip::tcp::resolver::query query(hostname, "");
+        boost::asio::ip::tcp::resolver::iterator end;
+
+        auto it = std::find_if(resolver.resolve(query), end, [](const boost::asio::ip::tcp::endpoint& ep) {
+            return ep.address().is_v4();
+        });
+
+        if (it != end) {
+            std::stringstream ss;
+            ss << static_cast<boost::asio::ip::tcp::endpoint>(*it).address();
+            return ss.str();
+        }
+
+        LOG(warn) << "could not find ipv4 address for hostname '" << hostname << "'";
+
+        return "";
+    } catch (std::exception& e) {
+        LOG(error) << "could not resolve hostname '" << hostname << "', reason: " << e.what();
+        return "";
+    }
+}
+
+inline std::string getIpFromHostname(const std::string& hostname, boost::asio::io_service& ios)
+{
+    try {
+        boost::asio::ip::tcp::resolver resolver(ios);
+        boost::asio::ip::tcp::resolver::query query(hostname, "");
+        boost::asio::ip::tcp::resolver::iterator end;
+
+        auto it = std::find_if(resolver.resolve(query), end, [](const boost::asio::ip::tcp::endpoint& ep) {
+            return ep.address().is_v4();
+        });
+
+        if (it != end) {
+            std::stringstream ss;
+            ss << static_cast<boost::asio::ip::tcp::endpoint>(*it).address();
+            return ss.str();
+        }
+
+        LOG(warn) << "could not find ipv4 address for hostname '" << hostname << "'";
+
+        return "";
+    } catch (std::exception& e) {
+        LOG(error) << "could not resolve hostname '" << hostname << "', reason: " << e.what();
+        return "";
+    }
+}
+
 } /* namespace tools */
 } /* namespace mq */
 } /* namespace fair */