From c35eb35bb63a97b7c46e879819757a9cb48165b5 Mon Sep 17 00:00:00 2001
From: Thomas Vanbesien <tvanbesi@proton.me>
Date: Tue, 17 Feb 2026 02:27:51 +0100
Subject: Initial commit: OPC UA discovery project

CMake-based C project using open62541 for OPC UA discovery.
Includes Local Discovery Server, register server, and find
servers client with OpenSSL encryption support.
---
 src/common.h | 115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 src/common.h

(limited to 'src/common.h')

diff --git a/src/common.h b/src/common.h
new file mode 100644
index 0000000..e3d2f4c
--- /dev/null
+++ b/src/common.h
@@ -0,0 +1,115 @@
+#ifndef DISCOVERY_COMMON_H
+#define DISCOVERY_COMMON_H
+
+/**
+ * @file  common.h
+ * @brief Shared helpers for the OPC UA discovery demo programs.
+ *
+ * Provides file-loading, factory, and output formatting functions used by
+ * the LDS, the registering server, and the FindServers client.
+ */
+
+#include <open62541/client.h>
+#include <open62541/server.h>
+#include <open62541/types.h>
+
+/**
+ * @brief Loads a DER-encoded certificate or key file into a UA_ByteString.
+ *
+ * @param path File path to read.
+ * @return The file contents, or UA_BYTESTRING_NULL on error.
+ */
+UA_ByteString loadFile (const char *const path);
+
+/**
+ * @brief Creates a UA_Server configured with security policies and encryption.
+ *
+ * The server is initialized with the specified port, certificate, private key,
+ * and trustlist. The applicationUri is set in the server's application
+ * description.
+ *
+ * @param port Server port number.
+ * @param applicationUri OPC UA application URI.
+ * @param certPath Path to server certificate (.der).
+ * @param keyPath Path to private key (.der).
+ * @param trustPaths Array of trustlist file paths (may be NULL if trustSize is
+ * 0).
+ * @param trustSize Number of entries in trustPaths.
+ * @param retval Output parameter set to the status code on failure.
+ * @return A configured UA_Server, or NULL on error.
+ */
+UA_Server *createSecureServer (UA_UInt16 port, const char *applicationUri,
+                               const char *certPath, const char *keyPath,
+                               char **trustPaths, size_t trustSize,
+                               UA_StatusCode *retval);
+
+/**
+ * @brief Parses a security mode name into the corresponding enum value.
+ *
+ * Accepted names: "None", "Sign", "SignAndEncrypt".
+ *
+ * @param name Mode name string.
+ * @return The matching UA_MessageSecurityMode, or
+ * UA_MESSAGESECURITYMODE_INVALID if the name is not recognized.
+ */
+UA_MessageSecurityMode parseSecurityMode (const char *name);
+
+/**
+ * @brief Maps a short security policy name to its full OPC UA URI.
+ *
+ * Accepted names: "None", "Basic256Sha256", "Aes256_Sha256_RsaPss",
+ * "Aes128_Sha256_RsaOaep", "ECC_nistP256".
+ *
+ * @param shortName Short policy name.
+ * @return The full URI string, or NULL if the name is not recognized.
+ */
+const char *resolveSecurityPolicyUri (const char *shortName);
+
+/**
+ * @brief Initializes a UA_ClientConfig with encryption from file paths.
+ *
+ * The config must be zero-initialized by the caller before calling this
+ * function. Loads the certificate, private key, and trustlist, then applies
+ * default encryption settings.
+ *
+ * @param cc Pointer to a zero-initialized UA_ClientConfig.
+ * @param applicationUri OPC UA application URI.
+ * @param certPath Path to client certificate (.der).
+ * @param keyPath Path to private key (.der).
+ * @param trustPaths Array of trustlist file paths (may be NULL if trustSize is
+ * 0).
+ * @param trustSize Number of entries in trustPaths.
+ * @param securityMode Requested message security mode.
+ * @param securityPolicyUri Security policy URI string (e.g.
+ * "http://opcfoundation.org/UA/SecurityPolicy#Basic256Sha256").
+ * @return UA_STATUSCODE_GOOD on success, error code otherwise.
+ */
+UA_StatusCode createSecureClientConfig (
+    UA_ClientConfig *cc, const char *applicationUri, const char *certPath,
+    const char *keyPath, char **trustPaths, size_t trustSize,
+    UA_MessageSecurityMode securityMode, const char *securityPolicyUri);
+
+/**
+ * @brief Logs a UA_ApplicationDescription (server info from FindServers).
+ *
+ * Outputs the application URI, name, product URI, type, and discovery URLs
+ * via UA_LOG_INFO.
+ *
+ * @param description The application description to print.
+ * @param index Display index (e.g. position in the FindServers result array).
+ */
+void printApplicationDescription (const UA_ApplicationDescription *description,
+                                  size_t index);
+
+/**
+ * @brief Logs a UA_EndpointDescription in a compact one-line format.
+ *
+ * Outputs the endpoint URL, security level, security mode, and the short
+ * policy name (the part after '#') via UA_LOG_INFO.
+ *
+ * @param endpoint The endpoint description to print.
+ * @param index Display index (e.g. position in the GetEndpoints result array).
+ */
+void printEndpoint (const UA_EndpointDescription *endpoint, size_t index);
+
+#endif /* DISCOVERY_COMMON_H */
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