disable rpc on relays by default (#1383)

* disable rpc on relays by default

* add default inbound link as service node

* throw if public-ip and public-port are not set

llarp/config/config.cpp

@@ -464,13 +464,10 @@ namespace llarp
   void
   ApiConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
   {
-    (void)params;
-
-    constexpr bool DefaultRPCEnabled = true;
     constexpr auto DefaultRPCBindAddr = "tcp://127.0.0.1:1190";
 
     conf.defineOption<bool>(
-        "api", "enabled", false, DefaultRPCEnabled, AssignmentAcceptor(m_enableRPCServer));
+        "api", "enabled", false, not params.isRelay, AssignmentAcceptor(m_enableRPCServer));
 
     conf.defineOption<std::string>(
         "api", "bind", false, DefaultRPCBindAddr, [this](std::string arg) {

llarp/router/router.cpp

@@ -568,8 +568,22 @@ namespace llarp
         whitelistRouters,
         m_isServiceNode);
 
+    std::vector<LinksConfig::LinkInfo> inboundLinks = conf.links.m_InboundLinks;
+
+    if (inboundLinks.empty() and m_isServiceNode)
+    {
+      const auto& publicAddr = conf.router.m_publicAddress;
+      if (publicAddr.isEmpty() or not publicAddr.hasPort())
+      {
+        throw std::runtime_error(
+            "service node enabled but could not find a public IP to bind to; you need to set the "
+            "public-ip= and public-port= options");
+      }
+      inboundLinks.push_back(LinksConfig::LinkInfo{"0.0.0.0", AF_INET, *publicAddr.getPort()});
+    }
+
     // create inbound links, if we are a service node
-    for (const LinksConfig::LinkInfo& serverConfig : conf.links.m_InboundLinks)
+    for (const LinksConfig::LinkInfo& serverConfig : inboundLinks)
     {
       auto server = iwp::NewInboundLink(
           m_keyManager,
@@ -594,11 +608,6 @@ namespace llarp
       _linkManager.AddLink(std::move(server), true);
     }
 
-    if (conf.links.m_InboundLinks.empty() and m_isServiceNode)
-    {
-      throw std::runtime_error("service node enabled but have no inbound links");
-    }
-
     // Network config
     if (conf.network.m_enableProfiling.has_value() and not*conf.network.m_enableProfiling)
     {