2 meshlink++.h -- MeshLink C++ API
3 Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24 #include <new> // for 'placement new'
31 /// Severity of log messages generated by MeshLink.
32 typedef meshlink_log_level_t log_level_t;
34 /// Code of most recent error encountered.
35 typedef meshlink_errno_t errno_t;
37 /// A callback for receiving data from the mesh.
38 /** @param mesh A handle which represents an instance of MeshLink.
39 * @param source A pointer to a meshlink::node describing the source of the data.
40 * @param data A pointer to a buffer containing the data sent by the source.
41 * @param len The length of the received data.
43 typedef void (*receive_cb_t)(mesh *mesh, node *source, const void *data, size_t len);
45 /// A callback reporting node status changes.
46 /** @param mesh A handle which represents an instance of MeshLink.
47 * @param node A pointer to a meshlink::node describing the node whose status changed.
48 * @param reachable True if the node is reachable, false otherwise.
50 typedef void (*node_status_cb_t)(mesh *mesh, node *node, bool reachable);
52 /// A callback for receiving log messages generated by MeshLink.
53 /** @param mesh A handle which represents an instance of MeshLink.
54 * @param level An enum describing the severity level of the message.
55 * @param text A pointer to a string containing the textual log message.
57 typedef void (*log_cb_t)(mesh *mesh, log_level_t level, const char *text);
59 /// A callback for accepting incoming channels.
60 /** @param mesh A handle which represents an instance of MeshLink.
61 * @param channel A handle for the incoming channel.
62 * @param node The node from which this channel is being initiated.
63 * @param port The port number the peer wishes to connect to.
64 * @param data A pointer to a buffer containing data already received. (Not yet used.)
65 * @param len The length of the data. (Not yet used.)
67 * @return This function should return true if the application accepts the incoming channel, false otherwise.
68 * If returning false, the channel is invalid and may not be used anymore.
70 typedef bool (*channel_accept_cb_t)(mesh *mesh, channel *channel, node *node, uint16_t port, const void *data, size_t len);
72 /// A callback for receiving data from a channel.
73 /** @param mesh A handle which represents an instance of MeshLink.
74 * @param channel A handle for the channel.
75 * @param data A pointer to a buffer containing data sent by the source.
76 * @param len The length of the data.
78 typedef void (*channel_receive_cb_t)(mesh *mesh, channel *channel, const void *data, size_t len);
80 /// A class describing a MeshLink node.
81 class node: public meshlink_node_t {
84 /// A class describing a MeshLink channel.
85 class channel: public meshlink_channel_t {
88 /// A class describing a MeshLink mesh.
89 class mesh: public meshlink_handle_t {
97 /** instead of registerin callbacks you derive your own class and overwrite the following abstract member functions.
98 * These functions are run in MeshLink's own thread.
99 * It is therefore important that these functions use apprioriate methods (queues, pipes, locking, etc.)
100 * to hand the data over to the application's thread.
101 * These functions should also not block itself and return as quickly as possible.
102 * The default member functions are no-ops, so you are not required to overwrite all these member functions
105 /// This function is called whenever another node sends data to the local node.
106 virtual void receive(node* source, const void* data, size_t length) { /* do nothing */ }
108 /// This functions is called whenever another node's status changed.
109 virtual void node_status(node* peer, bool reachable) { /* do nothing */ }
111 /// This functions is called whenever MeshLink has some information to log.
112 virtual void log(log_level_t level, const char* message) { /* do nothing */ }
115 /** This function causes MeshLink to open network sockets, make outgoing connections, and
116 * create a new thread, which will handle all network I/O.
118 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
121 meshlink_set_receive_cb (this, &receive_trampoline);
122 meshlink_set_node_status_cb(this, &node_status_trampoline);
123 meshlink_set_log_cb (this, MESHLINK_DEBUG, &log_trampoline);
124 return meshlink_start(this);
128 /** This function causes MeshLink to disconnect from all other nodes,
129 * close all sockets, and shut down its own thread.
135 /// Send data to another node.
136 /** This functions sends one packet of data to another node in the mesh.
137 * The packet is sent using UDP semantics, which means that
138 * the packet is sent as one unit and is received as one unit,
139 * and that there is no guarantee that the packet will arrive at the destination.
140 * The application should take care of getting an acknowledgement and retransmission if necessary.
142 * @param destination A pointer to a meshlink::node describing the destination for the data.
143 * @param data A pointer to a buffer containing the data to be sent to the source.
144 * @param len The length of the data.
145 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
146 * A return value of true does not guarantee that the message will actually arrive at the destination.
148 bool send(node *destination, const void *data, unsigned int len) {
149 return meshlink_send(this, destination, data, len);
152 /// Get a handle for a specific node.
153 /** This function returns a handle for the node with the given name.
155 * @param name The name of the node for which a handle is requested.
157 * @return A pointer to a meshlink::node which represents the requested node,
158 * or NULL if the requested node does not exist.
160 node *get_node(const char *name) {
161 return (node *)meshlink_get_node(this, name);
164 /// Get a list of all nodes.
165 /** This function returns a list with handles for all known nodes.
167 * @param nodes A pointer to an array of pointers to meshlink::node, which should be allocated by the application.
168 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
170 * @return The number of known nodes, or -1 in case of an error.
171 * This can be larger than nmemb, in which case not all nodes were stored in the nodes array.
173 node **get_all_nodes(node **nodes, size_t *nmemb) {
174 return (node **)meshlink_get_all_nodes(this, (meshlink_node_t **)nodes, nmemb);
177 /// Sign data using the local node's MeshLink key.
178 /** This function signs data using the local node's MeshLink key.
179 * The generated signature can be securely verified by other nodes.
181 * @param data A pointer to a buffer containing the data to be signed.
182 * @param len The length of the data to be signed.
183 * @param signature A pointer to a buffer where the signature will be stored.
184 * @param siglen The size of the signature buffer. Will be changed after the call to match the size of the signature itself.
186 * @return This function returns true if the signature is valid, false otherwise.
188 bool sign(const void *data, size_t len, void *signature, size_t *siglen) {
189 return meshlink_sign(this, data, len, signature, siglen);
192 /// Verify the signature generated by another node of a piece of data.
193 /** This function verifies the signature that another node generated for a piece of data.
195 * @param source A pointer to a meshlink_node_t describing the source of the signature.
196 * @param data A pointer to a buffer containing the data to be verified.
197 * @param len The length of the data to be verified.
198 * @param signature A pointer to a string containing the signature.
199 * @param siglen The size of the signature.
201 * @return This function returns true if the signature is valid, false otherwise.
203 bool verify(node *source, const void *data, size_t len, const void *signature, size_t siglen) {
204 return meshlink_verify(this, source, data, len, signature, siglen);
207 /// Add an Address for the local node.
208 /** This function adds an Address for the local node, which will be used for invitation URLs.
210 * @param address A string containing the address, which can be either in numeric format or a hostname.
212 * @return This function returns true if the address was added, false otherwise.
214 bool add_address(const char *address) {
215 return meshlink_add_address(this, address);
218 /// Invite another node into the mesh.
219 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
220 * The generated invitation is a string containing a URL.
221 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
222 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
224 * @param name The name that the invitee will use in the mesh.
226 * @return This function returns a string that contains the invitation URL.
227 * The application should call free() after it has finished using the URL.
229 char *invite(const char *name) {
230 return meshlink_invite(this, name);
233 /// Use an invitation to join a mesh.
234 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
235 * An invitation can only be used if the local node has never connected to other nodes before.
236 * After a succesfully accepted invitation, the name of the local node may have changed.
238 * @param invitation A string containing the invitation URL.
240 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
242 bool join(const char *invitation) {
243 return meshlink_join(this, invitation);
246 /// Export the local node's key and addresses.
247 /** This function generates a string that contains the local node's public key and one or more IP addresses.
248 * The application can pass it in some way to another node, which can then import it,
249 * granting the local node access to the other node's mesh.
251 * @return This function returns a string that contains the exported key and addresses.
252 * The application should call free() after it has finished using this string.
255 return meshlink_export(this);
258 /// Import another node's key and addresses.
259 /** This function accepts a string containing the exported public key and addresses of another node.
260 * By importing this data, the local node grants the other node access to its mesh.
262 * @param data A string containing the other node's exported key and addresses.
264 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
266 bool import_key(const char *data) {
267 return meshlink_import(this, data);
270 /// Blacklist a node from the mesh.
271 /** This function causes the local node to blacklist another node.
272 * The local node will drop any existing connections to that node,
273 * and will not send data to it nor accept any data received from it any more.
275 * @param node A pointer to a meshlink::node describing the node to be blacklisted.
277 void blacklist(node *node) {
278 return meshlink_blacklist(this, node);
281 /// Set the accept callback.
282 /** This functions sets the callback that is called whenever another node sends data to the local node.
283 * The callback is run in MeshLink's own thread.
284 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
285 * to hand the data over to the application's thread.
286 * The callback should also not block itself and return as quickly as possible.
288 * @param channel A handle for the channel.
289 * @param cb A pointer to the function which will be called when another node sends data to the local node.
291 void set_channel_accept_cb(channel *channel, channel_accept_cb_t cb) {
292 return meshlink_set_channel_accept_cb(this, (meshlink_channel_accept_cb_t)cb);
295 /// Open a reliable stream channel to another node.
296 /** This function is called whenever a remote node wants to open a channel to the local node.
297 * The application then has to decide whether to accept or reject this channel.
299 * @param node The node to which this channel is being initiated.
300 * @param port The port number the peer wishes to connect to.
301 * @param cb A pointer to the function which will be called when the remote node sends data to the local node.
302 * @param data A pointer to a buffer containing data to already queue for sending.
303 * @param len The length of the data.
305 * @return A handle for the channel, or NULL in case of an error.
307 channel *channel_open(node *node, uint16_t port, channel_receive_cb_t cb, const void *data, size_t len) {
308 return (channel *)meshlink_channel_open(this, node, port, (meshlink_channel_receive_cb_t)cb, data, len);
311 /// Partially close a reliable stream channel.
312 /** This shuts down the read or write side of a channel, or both, without closing the handle.
313 * It can be used to inform the remote node that the local node has finished sending all data on the channel,
314 * but still allows waiting for incoming data from the remote node.
316 * @param channel A handle for the channel.
317 * @param direction Must be one of SHUT_RD, SHUT_WR or SHUT_RDWR.
319 void channel_shutdown(channel *channel, int direction) {
320 return meshlink_channel_shutdown(this, channel, direction);
323 /// Close a reliable stream channel.
324 /** This informs the remote node that the local node has finished sending all data on the channel.
325 * It also causes the local node to stop accepting incoming data from the remote node.
326 * Afterwards, the channel handle is invalid and must not be used any more.
328 * @param channel A handle for the channel.
330 void channel_close(meshlink_channel_t *channel) {
331 return meshlink_channel_close(this, channel);
334 /// Transmit data on a channel
335 /** This queues data to send to the remote node.
337 * @param channel A handle for the channel.
338 * @param data A pointer to a buffer containing data sent by the source.
339 * @param len The length of the data.
341 * @return The amount of data that was queued, which can be less than len, or a negative value in case of an error.
343 ssize_t channel_send(channel *channel, void *data, size_t len) {
344 return meshlink_channel_send(this, channel, data, len);
349 mesh(const mesh&) /* TODO: C++11: = delete */;
350 void operator=(const mesh&) /* TODO: C++11: = delete */ ;
352 /// static callback trampolines:
353 static void receive_trampoline(meshlink_handle_t* handle, meshlink_node_t* source, const void* data, size_t length)
355 mesh* that = static_cast<mesh*>(handle);
356 that->receive(static_cast<node*>(source), data, length);
359 static void node_status_trampoline(meshlink_handle_t* handle, meshlink_node_t* peer, bool reachable)
361 mesh* that = static_cast<mesh*>(handle);
362 that->node_status(static_cast<node*>(peer), reachable);
365 static void log_trampoline(meshlink_handle_t* handle, log_level_t level, const char* message)
367 mesh* that = static_cast<mesh*>(handle);
368 that->log(level, message);
372 /// Initialize MeshLink's configuration directory.
373 /** This function causes MeshLink to initialize its configuration directory,
374 * if it hasn't already been initialized.
375 * It only has to be run the first time the application starts,
376 * but it is not a problem if it is run more than once, as long as
377 * the arguments given are the same.
379 * This function does not start any network I/O yet. The application should
380 * first set callbacks, and then call meshlink_start().
382 * @param confbase The directory in which MeshLink will store its configuration files.
383 * @param name The name which this instance of the application will use in the mesh.
384 * @param appname The application name which will be used in the mesh.
386 * @return This function will return a pointer to a meshlink::mesh if MeshLink has succesfully set up its configuration files, NULL otherwise.
389 static MESH* open(const char *confbase, const char *name, const char* appname) {
390 void* mp = (void *)meshlink_open_with_size(confbase, name, appname, sizeof(MESH));
391 return new (mp) MESH;
394 /// Close the MeshLink handle.
395 /** This function calls meshlink_stop() if necessary,
396 * and frees all memory allocated by MeshLink.
397 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
399 static void close(mesh *mesh) {
400 meshlink_close(mesh);
403 static const char *strerror(errno_t err = meshlink_errno) {
404 return meshlink_strerror(err);
409 #endif // MESHLINKPP_H