Add --no-network option (#831)

- Add `--no-network` CLI option which disables all TCP/HTTPS listeners, restricting zenserver to Unix domain socket communication only. 
- Also fixes asio upgrade breakage on main

4 files changed, 29 insertions, 18 deletions

diff --git a/src/zenhttp/httpserver.cpp b/src/zenhttp/httpserver.cpp
index 1a0018908..6ba0ca563 100644
--- a/src/zenhttp/httpserver.cpp
+++ b/src/zenhttp/httpserver.cpp
@@ -1157,7 +1157,7 @@ CreateHttpServerClass(const std::string_view ServerClass, const HttpServerConfig
 		ZEN_INFO("using asio HTTP server implementation")
 		return CreateHttpAsioServer(AsioConfig {
 			.ThreadCount = Config.ThreadCount, .ForceLoopback = Config.ForceLoopback, .IsDedicatedServer = Config.IsDedicatedServer,
-			.UnixSocketPath = Config.UnixSocketPath,
+			.NoNetwork = Config.NoNetwork, .UnixSocketPath = Config.UnixSocketPath,
 #if ZEN_USE_OPENSSL
 			.HttpsPort = Config.HttpsPort, .CertFile = Config.CertFile, .KeyFile = Config.KeyFile,
 #endif
diff --git a/src/zenhttp/include/zenhttp/httpserver.h b/src/zenhttp/include/zenhttp/httpserver.h
index d98877d16..627e7921f 100644
--- a/src/zenhttp/include/zenhttp/httpserver.h
+++ b/src/zenhttp/include/zenhttp/httpserver.h
@@ -329,10 +329,11 @@ struct HttpServerConfig
 	std::vector<HttpServerPluginConfig> PluginConfigs;
 	bool								ForceLoopback = false;
 	unsigned int						ThreadCount	  = 0;
-	std::string							UnixSocketPath;	 // Unix domain socket path (empty = disabled, non-Windows only)
-	int									HttpsPort = 0;	 // HTTPS listen port (0 = disabled, ASIO backend)
-	std::string							CertFile;		 // PEM certificate chain file path
-	std::string							KeyFile;		 // PEM private key file path
+	std::string							UnixSocketPath;		// Unix domain socket path (empty = disabled, non-Windows only)
+	bool								NoNetwork = false;	// Disable TCP/HTTPS listeners; only accept connections via UnixSocketPath
+	int									HttpsPort = 0;		// HTTPS listen port (0 = disabled, ASIO backend)
+	std::string							CertFile;			// PEM certificate chain file path
+	std::string							KeyFile;			// PEM private key file path
 
 	struct
 	{
diff --git a/src/zenhttp/servers/httpasio.cpp b/src/zenhttp/servers/httpasio.cpp
index e8b27da70..643f33618 100644
--- a/src/zenhttp/servers/httpasio.cpp
+++ b/src/zenhttp/servers/httpasio.cpp
@@ -2157,15 +2157,18 @@ HttpAsioServerImpl::Start(uint16_t Port, const AsioConfig& Config)
 
 	ZEN_INFO("starting asio http with {} service threads", Config.ThreadCount);
 
-	m_Acceptor.reset(
-		new asio_http::HttpAcceptor(*this, m_IoService, Port, Config.ForceLoopback, /*AllowPortProbing */ !Config.IsDedicatedServer));
-
-	if (!m_Acceptor->IsValid())
+	if (!Config.NoNetwork)
 	{
-		return 0;
-	}
+		m_Acceptor.reset(
+			new asio_http::HttpAcceptor(*this, m_IoService, Port, Config.ForceLoopback, /*AllowPortProbing */ !Config.IsDedicatedServer));
+
+		if (!m_Acceptor->IsValid())
+		{
+			return 0;
+		}
 
-	m_Acceptor->Start();
+		m_Acceptor->Start();
+	}
 
 #if defined(ASIO_HAS_LOCAL_SOCKETS)
 	if (!Config.UnixSocketPath.empty())
@@ -2184,7 +2187,7 @@ HttpAsioServerImpl::Start(uint16_t Port, const AsioConfig& Config)
 #endif
 
 #if ZEN_USE_OPENSSL
-	if (!Config.CertFile.empty() && !Config.KeyFile.empty())
+	if (!Config.NoNetwork && !Config.CertFile.empty() && !Config.KeyFile.empty())
 	{
 		m_SslContext = std::make_unique<asio::ssl::context>(asio::ssl::context::tlsv12_server);
 		m_SslContext->set_options(asio::ssl::context::default_workarounds | asio::ssl::context::no_sslv2 | asio::ssl::context::no_sslv3 |
@@ -2243,12 +2246,18 @@ HttpAsioServerImpl::Start(uint16_t Port, const AsioConfig& Config)
 		});
 	}
 
-	ZEN_INFO("asio http started in {} mode, using {} threads on port {}",
-			 Config.IsDedicatedServer ? "DEDICATED" : "NORMAL",
-			 Config.ThreadCount,
-			 m_Acceptor->GetAcceptPort());
+	if (m_Acceptor)
+	{
+		ZEN_INFO("asio http started in {} mode, using {} threads on port {}",
+				 Config.IsDedicatedServer ? "DEDICATED" : "NORMAL",
+				 Config.ThreadCount,
+				 m_Acceptor->GetAcceptPort());
+
+		return m_Acceptor->GetAcceptPort();
+	}
 
-	return m_Acceptor->GetAcceptPort();
+	ZEN_INFO("asio http started in no-network mode, using {} threads (unix socket only)", Config.ThreadCount);
+	return Port;
 }
 
 void
diff --git a/src/zenhttp/servers/httpasio.h b/src/zenhttp/servers/httpasio.h
index 5adf4d5e8..21d10170e 100644
--- a/src/zenhttp/servers/httpasio.h
+++ b/src/zenhttp/servers/httpasio.h
@@ -11,6 +11,7 @@ struct AsioConfig
 	unsigned int ThreadCount	   = 0;
 	bool		 ForceLoopback	   = false;
 	bool		 IsDedicatedServer = false;
+	bool		 NoNetwork		   = false;
 	std::string	 UnixSocketPath;
 #if ZEN_USE_OPENSSL
 	int			HttpsPort = 0;	// 0 = auto-assign; set CertFile/KeyFile to enable HTTPS