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 port The port number the peer wishes to connect to.
63 * @param data A pointer to a buffer containing data already received. (Not yet used.)
64 * @param len The length of the data. (Not yet used.)
66 * @return This function should return true if the application accepts the incoming channel, false otherwise.
67 * If returning false, the channel is invalid and may not be used anymore.
69 typedef bool (*channel_accept_cb_t)(mesh *mesh, channel *channel, uint16_t port, const void *data, size_t len);
71 /// A callback for receiving data from a channel.
72 /** @param mesh A handle which represents an instance of MeshLink.
73 * @param channel A handle for the channel.
74 * @param data A pointer to a buffer containing data sent by the source.
75 * @param len The length of the data.
77 typedef void (*channel_receive_cb_t)(mesh *mesh, channel *channel, const void *data, size_t len);
79 /// A callback that is called when data can be send on a channel.
80 /** @param mesh A handle which represents an instance of MeshLink.
81 * @param channel A handle for the channel.
82 * @param len The maximum length of data that is guaranteed to be accepted by a call to channel_send().
84 typedef void (*channel_poll_cb_t)(mesh *mesh, channel *channel, size_t len);
86 /// A class describing a MeshLink node.
87 class node: public meshlink_node_t {
90 /// A class describing a MeshLink channel.
91 class channel: public meshlink_channel_t {
94 /// A class describing a MeshLink mesh.
103 bool isOpen() const {
107 // TODO: please enable C++11 in autoconf to enable "move constructors":
108 // mesh(mesh&& other)
109 // : handle(other.handle)
112 // handle->priv = this;
116 /// Initialize MeshLink's configuration directory.
117 /** This function causes MeshLink to initialize its configuration directory,
118 * if it hasn't already been initialized.
119 * It only has to be run the first time the application starts,
120 * but it is not a problem if it is run more than once, as long as
121 * the arguments given are the same.
123 * This function does not start any network I/O yet. The application should
124 * first set callbacks, and then call meshlink_start().
126 * @param confbase The directory in which MeshLink will store its configuration files.
127 * @param name The name which this instance of the application will use in the mesh.
128 * @param appname The application name which will be used in the mesh.
129 * @param dclass The device class which will be used in the mesh.
131 * @return This function will return a pointer to a meshlink::mesh if MeshLink has succesfully set up its configuration files, NULL otherwise.
133 bool open(const char *confbase, const char *name, const char* appname, dev_class_t devclass) {
134 handle = meshlink_open(confbase, name, appname, devclass);
141 mesh(const char *confbase, const char *name, const char* appname, dev_class_t devclass) {
142 open(confbase, name, appname, devclass);
145 /// Close the MeshLink handle.
146 /** This function calls meshlink_stop() if necessary,
147 * and frees all memory allocated by MeshLink.
148 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
154 meshlink_close(handle);
159 /** instead of registerin callbacks you derive your own class and overwrite the following abstract member functions.
160 * These functions are run in MeshLink's own thread.
161 * It is therefore important that these functions use apprioriate methods (queues, pipes, locking, etc.)
162 * to hand the data over to the application's thread.
163 * These functions should also not block itself and return as quickly as possible.
164 * The default member functions are no-ops, so you are not required to overwrite all these member functions
167 /// This function is called whenever another node sends data to the local node.
168 virtual void receive(node* source, const void* data, size_t length) { /* do nothing */ }
170 /// This functions is called whenever another node's status changed.
171 virtual void node_status(node* peer, bool reachable) { /* do nothing */ }
173 /// This functions is called whenever MeshLink has some information to log.
174 virtual void log(log_level_t level, const char* message) { /* do nothing */ }
176 /// This functions is called whenever another node attemps to open a channel to the local node.
178 * If the channel is accepted, the poll_callback will be set to channel_poll and can be
179 * changed using set_channel_poll_cb(). Likewise, the receive callback is set to
182 * The function is run in MeshLink's own thread.
183 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
184 * to pass data to or from the application's thread.
185 * The callback should also not block itself and return as quickly as possible.
187 * @param channel A handle for the incoming channel.
188 * @param port The port number the peer wishes to connect to.
189 * @param data A pointer to a buffer containing data already received. (Not yet used.)
190 * @param len The length of the data. (Not yet used.)
192 * @return This function should return true if the application accepts the incoming channel, false otherwise.
193 * If returning false, the channel is invalid and may not be used anymore.
195 virtual bool channel_accept(channel *channel, uint16_t port, const void *data, size_t len)
197 /* by default reject all channels */
201 /// This function is called by Meshlink for receiving data from a channel.
203 * The function is run in MeshLink's own thread.
204 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
205 * to pass data to or from the application's thread.
206 * The callback should also not block itself and return as quickly as possible.
208 * @param channel A handle for the channel.
209 * @param data A pointer to a buffer containing data sent by the source.
210 * @param len The length of the data.
212 virtual void channel_receive(channel *channel, const void *data, size_t len) { /* do nothing */ }
214 /// This function is called by Meshlink when data can be send on a channel.
216 * The function is run in MeshLink's own thread.
217 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
218 * to pass data to or from the application's thread.
220 * The callback should also not block itself and return as quickly as possible.
221 * @param channel A handle for the channel.
222 * @param len The maximum length of data that is guaranteed to be accepted by a call to channel_send().
224 virtual void channel_poll(channel *channel, size_t len) { /* do nothing */ }
227 /** This function causes MeshLink to open network sockets, make outgoing connections, and
228 * create a new thread, which will handle all network I/O.
230 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
233 meshlink_set_receive_cb (handle, &receive_trampoline);
234 meshlink_set_node_status_cb (handle, &node_status_trampoline);
235 meshlink_set_log_cb (handle, MESHLINK_DEBUG, &log_trampoline);
236 meshlink_set_channel_accept_cb(handle, &channel_accept_trampoline);
237 return meshlink_start (handle);
241 /** This function causes MeshLink to disconnect from all other nodes,
242 * close all sockets, and shut down its own thread.
245 meshlink_stop(handle);
248 /// Send data to another node.
249 /** This functions sends one packet of data to another node in the mesh.
250 * The packet is sent using UDP semantics, which means that
251 * the packet is sent as one unit and is received as one unit,
252 * and that there is no guarantee that the packet will arrive at the destination.
253 * The application should take care of getting an acknowledgement and retransmission if necessary.
255 * @param destination A pointer to a meshlink::node describing the destination for the data.
256 * @param data A pointer to a buffer containing the data to be sent to the source.
257 * @param len The length of the data.
258 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
259 * A return value of true does not guarantee that the message will actually arrive at the destination.
261 bool send(node *destination, const void *data, unsigned int len) {
262 return meshlink_send(handle, destination, data, len);
265 /// Get a handle for a specific node.
266 /** This function returns a handle for the node with the given name.
268 * @param name The name of the node for which a handle is requested.
270 * @return A pointer to a meshlink::node which represents the requested node,
271 * or NULL if the requested node does not exist.
273 node *get_node(const char *name) {
274 return (node *)meshlink_get_node(handle, name);
277 /// Get a list of all nodes.
278 /** This function returns a list with handles for all known nodes.
280 * @param nodes A pointer to an array of pointers to meshlink::node, which should be allocated by the application.
281 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
283 * @return The number of known nodes, or -1 in case of an error.
284 * This can be larger than nmemb, in which case not all nodes were stored in the nodes array.
286 node **get_all_nodes(node **nodes, size_t *nmemb) {
287 return (node **)meshlink_get_all_nodes(handle, (meshlink_node_t **)nodes, nmemb);
290 /// Sign data using the local node's MeshLink key.
291 /** This function signs data using the local node's MeshLink key.
292 * The generated signature can be securely verified by other nodes.
294 * @param data A pointer to a buffer containing the data to be signed.
295 * @param len The length of the data to be signed.
296 * @param signature A pointer to a buffer where the signature will be stored.
297 * @param siglen The size of the signature buffer. Will be changed after the call to match the size of the signature itself.
299 * @return This function returns true if the signature is valid, false otherwise.
301 bool sign(const void *data, size_t len, void *signature, size_t *siglen) {
302 return meshlink_sign(handle, data, len, signature, siglen);
305 /// Verify the signature generated by another node of a piece of data.
306 /** This function verifies the signature that another node generated for a piece of data.
308 * @param source A pointer to a meshlink_node_t describing the source of the signature.
309 * @param data A pointer to a buffer containing the data to be verified.
310 * @param len The length of the data to be verified.
311 * @param signature A pointer to a string containing the signature.
312 * @param siglen The size of the signature.
314 * @return This function returns true if the signature is valid, false otherwise.
316 bool verify(node *source, const void *data, size_t len, const void *signature, size_t siglen) {
317 return meshlink_verify(handle, source, data, len, signature, siglen);
320 /// Add an Address for the local node.
321 /** This function adds an Address for the local node, which will be used for invitation URLs.
323 * @param address A string containing the address, which can be either in numeric format or a hostname.
325 * @return This function returns true if the address was added, false otherwise.
327 bool add_address(const char *address) {
328 return meshlink_add_address(handle, address);
331 /// Invite another node into the mesh.
332 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
333 * The generated invitation is a string containing a URL.
334 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
335 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
337 * @param name The name that the invitee will use in the mesh.
339 * @return This function returns a string that contains the invitation URL.
340 * The application should call free() after it has finished using the URL.
342 char *invite(const char *name) {
343 return meshlink_invite(handle, name);
346 /// Use an invitation to join a mesh.
347 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
348 * An invitation can only be used if the local node has never connected to other nodes before.
349 * After a succesfully accepted invitation, the name of the local node may have changed.
351 * @param invitation A string containing the invitation URL.
353 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
355 bool join(const char *invitation) {
356 return meshlink_join(handle, invitation);
359 /// Export the local node's key and addresses.
360 /** This function generates a string that contains the local node's public key and one or more IP addresses.
361 * The application can pass it in some way to another node, which can then import it,
362 * granting the local node access to the other node's mesh.
364 * @return This function returns a string that contains the exported key and addresses.
365 * The application should call free() after it has finished using this string.
368 return meshlink_export(handle);
371 /// Import another node's key and addresses.
372 /** This function accepts a string containing the exported public key and addresses of another node.
373 * By importing this data, the local node grants the other node access to its mesh.
375 * @param data A string containing the other node's exported key and addresses.
377 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
379 bool import_key(const char *data) {
380 return meshlink_import(handle, data);
383 /// Blacklist a node from the mesh.
384 /** This function causes the local node to blacklist another node.
385 * The local node will drop any existing connections to that node,
386 * and will not send data to it nor accept any data received from it any more.
388 * @param node A pointer to a meshlink::node describing the node to be blacklisted.
390 void blacklist(node *node) {
391 return meshlink_blacklist(handle, node);
394 /// Set the poll callback.
395 /** This functions sets the callback that is called whenever data can be sent to another node.
396 * The callback is run in MeshLink's own thread.
397 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
398 * to pass data to or from the application's thread.
399 * The callback should also not block itself and return as quickly as possible.
401 * @param channel A handle for the channel.
402 * @param cb A pointer to the function which will be called when data can be sent to another node.
403 * If a NULL pointer is given, the callback will be disabled.
405 void set_channel_poll_cb(channel *channel, channel_poll_cb_t cb) {
406 meshlink_set_channel_poll_cb(handle, channel, (meshlink_channel_poll_cb_t)cb);
409 /// Open a reliable stream channel to another node.
410 /** This function is called whenever a remote node wants to open a channel to the local node.
411 * The application then has to decide whether to accept or reject this channel.
413 * This function sets the channel poll callback to channel_poll_trampoline, which in turn
414 * calls channel_poll. To set a differnt, channel-specific poll callback, use set_channel_poll_cb.
416 * @param node The node to which this channel is being initiated.
417 * @param port The port number the peer wishes to connect to.
418 * @param cb A pointer to the function which will be called when the remote node sends data to the local node.
419 * @param data A pointer to a buffer containing data to already queue for sending.
420 * @param len The length of the data.
422 * @return A handle for the channel, or NULL in case of an error.
424 channel *channel_open(node *node, uint16_t port, channel_receive_cb_t cb, const void *data, size_t len) {
425 channel *ch = (channel *)meshlink_channel_open(handle, node, port, (meshlink_channel_receive_cb_t)cb, data, len);
426 meshlink_set_channel_poll_cb(handle, ch, &channel_poll_trampoline);
432 * Sets channel_receive_trampoline as cb, which in turn calls this->channel_receive( ... ).
434 channel *channel_open(node *node, uint16_t port, const void *data, size_t len) {
435 channel *ch = (channel *)meshlink_channel_open(handle, node, port, &channel_receive_trampoline, data, len);
436 meshlink_set_channel_poll_cb(handle, ch, &channel_poll_trampoline);
440 /// Partially close a reliable stream channel.
441 /** This shuts down the read or write side of a channel, or both, without closing the handle.
442 * It can be used to inform the remote node that the local node has finished sending all data on the channel,
443 * but still allows waiting for incoming data from the remote node.
445 * @param channel A handle for the channel.
446 * @param direction Must be one of SHUT_RD, SHUT_WR or SHUT_RDWR.
448 void channel_shutdown(channel *channel, int direction) {
449 return meshlink_channel_shutdown(handle, channel, direction);
452 /// Close a reliable stream channel.
453 /** This informs the remote node that the local node has finished sending all data on the channel.
454 * It also causes the local node to stop accepting incoming data from the remote node.
455 * Afterwards, the channel handle is invalid and must not be used any more.
457 * @param channel A handle for the channel.
459 void channel_close(meshlink_channel_t *channel) {
460 return meshlink_channel_close(handle, channel);
463 /// Transmit data on a channel
464 /** This queues data to send to the remote node.
466 * @param channel A handle for the channel.
467 * @param data A pointer to a buffer containing data sent by the source.
468 * @param len The length of the data.
470 * @return The amount of data that was queued, which can be less than len, or a negative value in case of an error.
472 ssize_t channel_send(channel *channel, void *data, size_t len) {
473 return meshlink_channel_send(handle, channel, data, len);
478 mesh(const mesh&) /* TODO: C++11: = delete */;
479 void operator=(const mesh&) /* TODO: C++11: = delete */ ;
481 /// static callback trampolines:
482 static void receive_trampoline(meshlink_handle_t* handle, meshlink_node_t* source, const void* data, size_t length)
486 meshlink::mesh* that = static_cast<mesh*>(handle->priv);
487 that->receive(static_cast<node*>(source), data, length);
490 static void node_status_trampoline(meshlink_handle_t* handle, meshlink_node_t* peer, bool reachable)
494 meshlink::mesh* that = static_cast<mesh*>(handle->priv);
495 that->node_status(static_cast<node*>(peer), reachable);
498 static void log_trampoline(meshlink_handle_t* handle, log_level_t level, const char* message)
502 meshlink::mesh* that = static_cast<mesh*>(handle->priv);
503 that->log(level, message);
506 static bool channel_accept_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, uint16_t port, const void *data, size_t len)
510 meshlink::mesh* that = static_cast<mesh*>(handle->priv);
511 bool accepted = that->channel_accept(static_cast<meshlink::channel*>(channel), port, data, len);
514 meshlink_set_channel_receive_cb(handle, channel, &channel_receive_trampoline);
515 meshlink_set_channel_poll_cb(handle, channel, &channel_poll_trampoline);
520 static void channel_receive_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, const void* data, size_t len)
524 meshlink::mesh* that = static_cast<mesh*>(handle->priv);
525 that->channel_receive(static_cast<meshlink::channel*>(channel), data, len);
528 static void channel_poll_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, size_t len)
532 meshlink::mesh* that = static_cast<mesh*>(handle->priv);
533 that->channel_poll(static_cast<meshlink::channel*>(channel), len);
536 meshlink_handle_t* handle;
539 static const char *strerror(errno_t err = meshlink_errno) {
540 return meshlink_strerror(err);
545 #endif // MESHLINKPP_H