ua_plugin_network.h 9.4 KB

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  1. /* This Source Code Form is subject to the terms of the Mozilla Public
  2. * License, v. 2.0. If a copy of the MPL was not distributed with this
  3. * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  4. *
  5. * Copyright 2017 (c) Fraunhofer IOSB (Author: Julius Pfrommer)
  6. * Copyright 2017 (c) Stefan Profanter, fortiss GmbH
  7. */
  8. #ifndef UA_PLUGIN_NETWORK_H_
  9. #define UA_PLUGIN_NETWORK_H_
  10. #ifdef __cplusplus
  11. extern "C" {
  12. #endif
  13. #include "ua_server.h"
  14. #include "ua_plugin_log.h"
  15. /* Forward declarations */
  16. struct UA_Connection;
  17. typedef struct UA_Connection UA_Connection;
  18. struct UA_SecureChannel;
  19. typedef struct UA_SecureChannel UA_SecureChannel;
  20. struct UA_ServerNetworkLayer;
  21. typedef struct UA_ServerNetworkLayer UA_ServerNetworkLayer;
  22. /**
  23. * .. _networking:
  24. *
  25. * Networking Plugin API
  26. * =====================
  27. *
  28. * Connection
  29. * ----------
  30. * Client-server connections are represented by a `UA_Connection`. The
  31. * connection is stateful and stores partially received messages, and so on. In
  32. * addition, the connection contains function pointers to the underlying
  33. * networking implementation. An example for this is the `send` function. So the
  34. * connection encapsulates all the required networking functionality. This lets
  35. * users on embedded (or otherwise exotic) systems implement their own
  36. * networking plugins with a clear interface to the main open62541 library. */
  37. typedef struct {
  38. UA_UInt32 protocolVersion;
  39. UA_UInt32 sendBufferSize;
  40. UA_UInt32 recvBufferSize;
  41. UA_UInt32 maxMessageSize;
  42. UA_UInt32 maxChunkCount;
  43. } UA_ConnectionConfig;
  44. typedef enum {
  45. UA_CONNECTION_CLOSED, /* The socket has been closed and the connection
  46. * will be deleted */
  47. UA_CONNECTION_OPENING, /* The socket is open, but the HEL/ACK handshake
  48. * is not done */
  49. UA_CONNECTION_ESTABLISHED /* The socket is open and the connection
  50. * configured */
  51. } UA_ConnectionState;
  52. struct UA_Connection {
  53. UA_ConnectionState state;
  54. UA_ConnectionConfig localConf;
  55. UA_ConnectionConfig remoteConf;
  56. UA_SecureChannel *channel; /* The securechannel that is attached to
  57. * this connection */
  58. UA_Int32 sockfd; /* Most connectivity solutions run on
  59. * sockets. Having the socket id here
  60. * simplifies the design. */
  61. UA_DateTime openingDate; /* The date the connection was created */
  62. void *handle; /* A pointer to internal data */
  63. UA_ByteString incompleteMessage; /* A half-received message (TCP is a
  64. * streaming protocol) is stored here */
  65. /* Get a buffer for sending */
  66. UA_StatusCode (*getSendBuffer)(UA_Connection *connection, size_t length,
  67. UA_ByteString *buf);
  68. /* Release the send buffer manually */
  69. void (*releaseSendBuffer)(UA_Connection *connection, UA_ByteString *buf);
  70. /* Sends a message over the connection. The message buffer is always freed,
  71. * even if sending fails.
  72. *
  73. * @param connection The connection
  74. * @param buf The message buffer
  75. * @return Returns an error code or UA_STATUSCODE_GOOD. */
  76. UA_StatusCode (*send)(UA_Connection *connection, UA_ByteString *buf);
  77. /* Receive a message from the remote connection
  78. *
  79. * @param connection The connection
  80. * @param response The response string. It is allocated by the connection
  81. * and needs to be freed with connection->releaseBuffer
  82. * @param timeout Timeout of the recv operation in milliseconds
  83. * @return Returns UA_STATUSCODE_BADCOMMUNICATIONERROR if the recv operation
  84. * can be repeated, UA_STATUSCODE_GOOD if it succeeded and
  85. * UA_STATUSCODE_BADCONNECTIONCLOSED if the connection was
  86. * closed. */
  87. UA_StatusCode (*recv)(UA_Connection *connection, UA_ByteString *response,
  88. UA_UInt32 timeout);
  89. /* Release the buffer of a received message */
  90. void (*releaseRecvBuffer)(UA_Connection *connection, UA_ByteString *buf);
  91. /* Close the connection. The network layer closes the socket. This is picked
  92. * up during the next 'listen' and the connection is freed in the network
  93. * layer. */
  94. void (*close)(UA_Connection *connection);
  95. /* To be called only from within the server (and not the network layer).
  96. * Frees up the connection's memory. */
  97. void (*free)(UA_Connection *connection);
  98. };
  99. /* Cleans up half-received messages, and so on. Called from connection->free. */
  100. void UA_EXPORT
  101. UA_Connection_deleteMembers(UA_Connection *connection);
  102. /**
  103. * Server Network Layer
  104. * --------------------
  105. * The server exposes two functions to interact with remote clients:
  106. * `processBinaryMessage` and `removeConnection`. These functions are called by
  107. * the server network layer.
  108. *
  109. * It is the job of the server network layer to listen on a TCP socket, to
  110. * accept new connections, to call the server with received messages and to
  111. * signal closed connections to the server.
  112. *
  113. * The network layer is part of the server config. So users can provide a custom
  114. * implementation if the provided example does not fit their architecture. The
  115. * network layer is invoked only from the server's main loop. So the network
  116. * layer does not need to be thread-safe. If the networklayer receives a
  117. * positive duration for blocking listening, the server's main loop will block
  118. * until a message is received or the duration times out. */
  119. /* Process a binary message (TCP packet). The message can contain partial
  120. * chunks. (TCP is a streaming protocol and packets may be split/merge during
  121. * transport.) After processing, the message is freed with
  122. * connection->releaseRecvBuffer. */
  123. void UA_EXPORT
  124. UA_Server_processBinaryMessage(UA_Server *server, UA_Connection *connection,
  125. UA_ByteString *message);
  126. /* The server internally cleans up the connection and then calls
  127. * connection->free. */
  128. void UA_EXPORT
  129. UA_Server_removeConnection(UA_Server *server, UA_Connection *connection);
  130. struct UA_ServerNetworkLayer {
  131. void *handle; /* Internal data */
  132. UA_String discoveryUrl;
  133. /* Start listening on the networklayer.
  134. *
  135. * @param nl The network layer
  136. * @return Returns UA_STATUSCODE_GOOD or an error code. */
  137. UA_StatusCode (*start)(UA_ServerNetworkLayer *nl, const UA_String *customHostname);
  138. /* Listen for new and closed connections and arriving packets. Calls
  139. * UA_Server_processBinaryMessage for the arriving packets. Closed
  140. * connections are picked up here and forwarded to
  141. * UA_Server_removeConnection where they are cleaned up and freed.
  142. *
  143. * @param nl The network layer
  144. * @param server The server for processing the incoming packets and for
  145. * closing connections.
  146. * @param timeout The timeout during which an event must arrive in
  147. * milliseconds
  148. * @return A statuscode for the status of the network layer. */
  149. UA_StatusCode (*listen)(UA_ServerNetworkLayer *nl, UA_Server *server,
  150. UA_UInt16 timeout);
  151. /* Close the network socket and all open connections. Afterwards, the
  152. * network layer can be safely deleted.
  153. *
  154. * @param nl The network layer
  155. * @param server The server that processes the incoming packets and for
  156. * closing connections before deleting them.
  157. * @return A statuscode for the status of the closing operation. */
  158. void (*stop)(UA_ServerNetworkLayer *nl, UA_Server *server);
  159. /* Deletes the network layer context. Call only after stopping. */
  160. void (*deleteMembers)(UA_ServerNetworkLayer *nl);
  161. };
  162. /**
  163. * Client Network Layer
  164. * --------------------
  165. * The client has only a single connection used for sending and receiving binary
  166. * messages. */
  167. /* @param localConf the connection config for this client
  168. * @param endpointUrl to where to connect
  169. * @param timeout in ms until the connection try times out if remote not reachable
  170. * @param logger the logger to use */
  171. typedef UA_Connection
  172. (*UA_ConnectClientConnection)(UA_ConnectionConfig localConf, const char *endpointUrl,
  173. const UA_UInt32 timeout, UA_Logger logger);
  174. /**
  175. * Endpoint URL Parser
  176. * -------------------
  177. * The endpoint URL parser is generally useful for the implementation of network
  178. * layer plugins. */
  179. /* Split the given endpoint url into hostname, port and path. All arguments must
  180. * be non-NULL. EndpointUrls have the form "opc.tcp://hostname:port/path", port
  181. * and path may be omitted (together with the prefix colon and slash).
  182. *
  183. * @param endpointUrl The endpoint URL.
  184. * @param outHostname Set to the parsed hostname. The string points into the
  185. * original endpointUrl, so no memory is allocated. If an IPv6 address is
  186. * given, hostname contains e.g. '[2001:0db8:85a3::8a2e:0370:7334]'
  187. * @param outPort Set to the port of the url or left unchanged.
  188. * @param outPath Set to the path if one is present in the endpointUrl.
  189. * Starting or trailing '/' are NOT included in the path. The string
  190. * points into the original endpointUrl, so no memory is allocated.
  191. * @return Returns UA_STATUSCODE_BADTCPENDPOINTURLINVALID if parsing failed. */
  192. UA_StatusCode UA_EXPORT
  193. UA_parseEndpointUrl(const UA_String *endpointUrl, UA_String *outHostname,
  194. UA_UInt16 *outPort, UA_String *outPath);
  195. #ifdef __cplusplus
  196. } // extern "C"
  197. #endif
  198. #endif /* UA_PLUGIN_NETWORK_H_ */