support configuring SSL TCP sockets for non-blocking operations;

src/common/network/tcp/SecureTcpClient.h

@@ -4,7 +4,7 @@
  * GPLv2 Open Source. Use is subject to license terms.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
- *  Copyright (C) 2024 Bryan Biedenkapp, N2PLL
+ *  Copyright (C) 2024-2025 Bryan Biedenkapp, N2PLL
  *
  */
 /**
@@ -56,8 +56,9 @@ namespace network
              * @param sslCtx Instance of the OpenSSL context.
              * @param client Address for client.
              * @param clientLen Length of sockaddr_in structure.
+             * @param nonBlocking Flag indicating socket operations should be non-blocking.
              */
-            SecureTcpClient(const int fd, SSL_CTX* sslCtx, sockaddr_in& client, int clientLen) : Socket(fd),
+            SecureTcpClient(const int fd, SSL_CTX* sslCtx, sockaddr_in& client, int clientLen, bool nonBlocking) : Socket(fd),
                 m_sockaddr(),
                 m_pSSL(nullptr),
                 m_pSSLCtx(nullptr)
@@ -135,6 +136,7 @@ namespace network
                 } while (status == 1 && !SSL_is_init_finished(m_pSSL));
 
                 // reset socket blocking operations
+                if (!nonBlocking) {
                     flags = fcntl(fd, F_GETFL, 0);
                     if (flags < 0) {
                         LogError(LOG_NET, "failed fcntl(F_GETFL), err: %d", errno);
@@ -146,12 +148,14 @@ namespace network
                         throw std::runtime_error("Cannot accept SSL client");
                     }
                 }
+            }
             /**
              * @brief Initializes a new instance of the SecureTcpClient class.
              * @param address IP Address.
              * @param port Port.
+             * @param nonBlocking Flag indicating socket operations should be non-blocking.
              */
-            SecureTcpClient(const std::string& address, const uint16_t port) : 
+            SecureTcpClient(const std::string& address, const uint16_t port, bool nonBlocking) : 
                 m_pSSL(nullptr),
                 m_pSSLCtx(nullptr)
             {
@@ -180,6 +184,20 @@ namespace network
                     LogError(LOG_NET, "Failed to connect to server, %s err: %d", ERR_error_string(ERR_get_error(), NULL), errno);
                     throw std::runtime_error("Failed to SSL connect to server");
                 }
+            
+                // setup socket for non-blocking operations
+                if (nonBlocking) {
+                    int flags = fcntl(m_fd, F_GETFL, 0);
+                    if (flags < 0) {
+                        LogError(LOG_NET, "failed fcntl(F_GETFL), err: %d", errno);
+                        throw std::runtime_error("Failed to set SSL server connection to non-blocking");
+                    }
+
+                    if (fcntl(m_fd, F_SETFL, flags | O_NONBLOCK) < 0) {
+                        LogError(LOG_NET, "failed fcntl(F_SETFL), err: %d", errno);
+                        throw std::runtime_error("Failed to set SSL server connection to non-blocking");
+                    }
+                }
             }
             /**
              * @brief Finalizes a instance of the SecureTcpClient class.

src/common/network/tcp/SecureTcpListener.h

@@ -7,7 +7,7 @@
 * @package DVM / Common Library
 * @license GPLv2 License (https://opensource.org/licenses/GPL-2.0)
 *
-*  Copyright (C) 2024 Bryan Biedenkapp, N2PLL
+*  Copyright (C) 2024-2025 Bryan Biedenkapp, N2PLL
 *
 */
 /**
@@ -109,9 +109,10 @@ namespace network
 
             /**
              * @brief Accept a new TCP connection either secure or unsecure.
+             * @param nonBlocking Flag indicating accepted TCP connections should use non-blocking sockets.
              * @returns SecureTcpClient* Newly accepted TCP connection.
              */
-            [[nodiscard]] SecureTcpClient* accept()
+            [[nodiscard]] SecureTcpClient* accept(bool nonBlocking = false)
             {
                 sockaddr_in client = {};
                 socklen_t clientLen = sizeof(client);
@@ -120,7 +121,7 @@ namespace network
                     return nullptr;
                 }
 
-                return new SecureTcpClient(fd, m_pSSLCtx, client, clientLen);
+                return new SecureTcpClient(fd, m_pSSLCtx, client, clientLen, nonBlocking);
             }
 
         private: