Allow programmatic configuration of unicast relays.

include/gz/transport/Discovery.hh

@@ -740,6 +740,26 @@ namespace gz
         }
       }
 
+      /// \brief Register a new relay address.
+      /// \param[in] _ip New IP address.
+      public: void AddRelayAddress(const std::string &_ip)
+      {
+        // Sanity check: Make sure that this IP address is not already saved.
+        for (auto const &addr : this->relayAddrs)
+        {
+          if (addr.sin_addr.s_addr == inet_addr(_ip.c_str()))
+            return;
+        }
+
+        sockaddr_in addr;
+        memset(&addr, 0, sizeof(addr));
+        addr.sin_family = AF_INET;
+        addr.sin_addr.s_addr = inet_addr(_ip.c_str());
+        addr.sin_port = htons(static_cast<u_short>(this->port));
+
+        this->relayAddrs.push_back(addr);
+      }
+
       /// \brief Broadcast periodic heartbeats.
       private: void UpdateHeartbeat()
       {
@@ -1420,26 +1440,6 @@ namespace gz
         return true;
       }
 
-      /// \brief Register a new relay address.
-      /// \param[in] _ip New IP address.
-      private: void AddRelayAddress(const std::string &_ip)
-      {
-        // Sanity check: Make sure that this IP address is not already saved.
-        for (auto const &addr : this->relayAddrs)
-        {
-          if (addr.sin_addr.s_addr == inet_addr(_ip.c_str()))
-            return;
-        }
-
-        sockaddr_in addr;
-        memset(&addr, 0, sizeof(addr));
-        addr.sin_family = AF_INET;
-        addr.sin_addr.s_addr = inet_addr(_ip.c_str());
-        addr.sin_port = htons(static_cast<u_short>(this->port));
-
-        this->relayAddrs.push_back(addr);
-      }
-
       /// \brief Default activity interval value (ms.).
       /// \sa ActivityInterval.
       /// \sa SetActivityInterval.

include/gz/transport/NodeOptions.hh

@@ -20,6 +20,7 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "gz/transport/config.hh"
 #include "gz/transport/Export.hh"
@@ -126,6 +127,19 @@ namespace gz
       public: bool TopicRemap(const std::string &_fromTopic,
                               std::string &_toTopic) const;
 
+      /// \brief Add relay IPs. This node will send UDP unicast traffic to these
+      /// addresses to connect networks when UDP multicast traffic is not
+      /// forwarded.
+      /// It's also possible to use the environment variable GZ_RELAY to add
+      /// relays.
+      /// \param[in] _relayIPs IPv4 addresses of unicast relays to add.
+      /// \return True if the relay list is valid or false otherwise.
+      public: bool SetRelays(const std::vector<std::string>& _relayIPs);
+
+      /// \brief Gets the list of relay addresses specified in this NodeOptions.
+      /// \return The list of relay addresses.
+      public: const std::vector<std::string>& Relays() const;
+
 #ifdef _WIN32
 // Disable warning C4251 which is triggered by
 // std::unique_ptr

src/Node.cc

@@ -512,6 +512,12 @@ Node::Node(const NodeOptions &_options)
 
   // Save the options.
   this->dataPtr->options = _options;
+
+  // Add relays from the node options.
+  for(const auto& addr : _options.Relays()) {
+    this->dataPtr->shared->dataPtr->msgDiscovery->AddRelayAddress(addr);
+    this->dataPtr->shared->dataPtr->srvDiscovery->AddRelayAddress(addr);
+  }
 }
 
 //////////////////////////////////////////////////

src/NodeOptions.cc

@@ -17,6 +17,7 @@
 
 #include <iostream>
 #include <string>
+#include <vector>
 
 #include "gz/transport/Helpers.hh"
 #include "gz/transport/NodeOptions.hh"
@@ -136,3 +137,15 @@ bool NodeOptions::TopicRemap(const std::string &_fromTopic,
 
   return topicIt != this->dataPtr->topicsRemap.end();
 }
+
+//////////////////////////////////////////////////
+bool NodeOptions::SetRelays(const std::vector<std::string>& _relayIPs) {
+  this->dataPtr->relayIPs = _relayIPs;
+  return true;
+}
+
+//////////////////////////////////////////////////
+const std::vector<std::string>& NodeOptions::Relays() const {
+  return this->dataPtr->relayIPs;
+}
+

src/NodeOptionsPrivate.hh

@@ -20,6 +20,7 @@
 
 #include <map>
 #include <string>
+#include <vector>
 
 #include "gz/transport/config.hh"
 #include "gz/transport/NetUtils.hh"
@@ -50,6 +51,9 @@ namespace gz
       /// \brief Table of remappings. The key is the original topic name and
       /// its value is the new topic name to be used instead.
       public: std::map<std::string, std::string> topicsRemap;
+
+      /// \brief List of unicast relay IPs.
+      public: std::vector<std::string> relayIPs;
     };
     }
   }

src/NodeOptions_TEST.cc

@@ -74,4 +74,11 @@ TEST(NodeOptionsTest, accessors)
   EXPECT_EQ(opts.Partition(), defaultPartition);
   EXPECT_TRUE(opts.SetPartition(aPartition));
   EXPECT_EQ(opts.Partition(), aPartition);
+
+  // Relay
+  std::string aRelay = "123.45.67.89";
+  EXPECT_TRUE(opts.SetRelays({aRelay}));
+  auto relays = opts.Relays();
+  ASSERT_EQ(relays.size(), 1);
+  EXPECT_EQ(relays[0], aRelay);
 }