5 meshlink++.h -- MeshLink C++ API
6 Copyright (C) 2014, 2017 Guus Sliepen <guus@meshlink.io>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 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 {
93 static const uint32_t RELIABLE = MESHLINK_CHANNEL_RELIABLE;
94 static const uint32_t ORDERED = MESHLINK_CHANNEL_ORDERED;
95 static const uint32_t FRAMED = MESHLINK_CHANNEL_FRAMED;
96 static const uint32_t DROP_LATE = MESHLINK_CHANNEL_DROP_LATE;
97 static const uint32_t TCP = MESHLINK_CHANNEL_TCP;
98 static const uint32_t UDP = MESHLINK_CHANNEL_UDP;
101 /// A class describing a MeshLink mesh.
104 mesh() : handle(0) {}
110 bool isOpen() const {
111 return (handle != 0);
114 // TODO: please enable C++11 in autoconf to enable "move constructors":
115 // mesh(mesh&& other)
116 // : handle(other.handle)
119 // handle->priv = this;
123 /// Initialize MeshLink's configuration directory.
124 /** This function causes MeshLink to initialize its configuration directory,
125 * if it hasn't already been initialized.
126 * It only has to be run the first time the application starts,
127 * but it is not a problem if it is run more than once, as long as
128 * the arguments given are the same.
130 * This function does not start any network I/O yet. The application should
131 * first set callbacks, and then call meshlink_start().
133 * @param confbase The directory in which MeshLink will store its configuration files.
134 * @param name The name which this instance of the application will use in the mesh.
135 * @param appname The application name which will be used in the mesh.
136 * @param dclass The device class which will be used in the mesh.
138 * @return This function will return a pointer to a meshlink::mesh if MeshLink has succesfully set up its configuration files, NULL otherwise.
140 bool open(const char *confbase, const char *name, const char *appname, dev_class_t devclass) {
141 handle = meshlink_open(confbase, name, appname, devclass);
148 mesh(const char *confbase, const char *name, const char *appname, dev_class_t devclass) {
149 open(confbase, name, appname, devclass);
152 /// Close the MeshLink handle.
153 /** This function calls meshlink_stop() if necessary,
154 * and frees all memory allocated by MeshLink.
155 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
160 meshlink_close(handle);
165 /** instead of registerin callbacks you derive your own class and overwrite the following abstract member functions.
166 * These functions are run in MeshLink's own thread.
167 * It is therefore important that these functions use apprioriate methods (queues, pipes, locking, etc.)
168 * to hand the data over to the application's thread.
169 * These functions should also not block itself and return as quickly as possible.
170 * The default member functions are no-ops, so you are not required to overwrite all these member functions
173 /// This function is called whenever another node sends data to the local node.
174 virtual void receive(node *source, const void *data, size_t length) { /* do nothing */ }
176 /// This functions is called whenever another node's status changed.
177 virtual void node_status(node *peer, bool reachable) { /* do nothing */ }
179 /// This functions is called whenever MeshLink has some information to log.
180 virtual void log(log_level_t level, const char *message) { /* do nothing */ }
182 /// This functions is called whenever another node attemps to open a channel to the local node.
184 * If the channel is accepted, the poll_callback will be set to channel_poll and can be
185 * changed using set_channel_poll_cb(). Likewise, the receive callback is set to
188 * The function is run in MeshLink's own thread.
189 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
190 * to pass data to or from the application's thread.
191 * The callback should also not block itself and return as quickly as possible.
193 * @param channel A handle for the incoming channel.
194 * @param port The port number the peer wishes to connect to.
195 * @param data A pointer to a buffer containing data already received. (Not yet used.)
196 * @param len The length of the data. (Not yet used.)
198 * @return This function should return true if the application accepts the incoming channel, false otherwise.
199 * If returning false, the channel is invalid and may not be used anymore.
201 virtual bool channel_accept(channel *channel, uint16_t port, const void *data, size_t len) {
202 /* by default reject all channels */
206 /// This function is called by Meshlink for receiving data from a channel.
208 * The function is run in MeshLink's own thread.
209 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
210 * to pass data to or from the application's thread.
211 * The callback should also not block itself and return as quickly as possible.
213 * @param channel A handle for the channel.
214 * @param data A pointer to a buffer containing data sent by the source.
215 * @param len The length of the data.
217 virtual void channel_receive(channel *channel, const void *data, size_t len) { /* do nothing */ }
219 /// This function is called by Meshlink when data can be send on a channel.
221 * The function is run in MeshLink's own thread.
222 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
223 * to pass data to or from the application's thread.
225 * The callback should also not block itself and return as quickly as possible.
226 * @param channel A handle for the channel.
227 * @param len The maximum length of data that is guaranteed to be accepted by a call to channel_send().
229 virtual void channel_poll(channel *channel, size_t len) { /* do nothing */ }
232 /** This function causes MeshLink to open network sockets, make outgoing connections, and
233 * create a new thread, which will handle all network I/O.
235 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
238 meshlink_set_receive_cb(handle, &receive_trampoline);
239 meshlink_set_node_status_cb(handle, &node_status_trampoline);
240 meshlink_set_log_cb(handle, MESHLINK_DEBUG, &log_trampoline);
241 meshlink_set_channel_accept_cb(handle, &channel_accept_trampoline);
242 return meshlink_start(handle);
246 /** This function causes MeshLink to disconnect from all other nodes,
247 * close all sockets, and shut down its own thread.
250 meshlink_stop(handle);
253 /// Send data to another node.
254 /** This functions sends one packet of data to another node in the mesh.
255 * The packet is sent using UDP semantics, which means that
256 * the packet is sent as one unit and is received as one unit,
257 * and that there is no guarantee that the packet will arrive at the destination.
258 * The application should take care of getting an acknowledgement and retransmission if necessary.
260 * @param destination A pointer to a meshlink::node describing the destination for the data.
261 * @param data A pointer to a buffer containing the data to be sent to the source.
262 * @param len The length of the data.
263 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
264 * A return value of true does not guarantee that the message will actually arrive at the destination.
266 bool send(node *destination, const void *data, unsigned int len) {
267 return meshlink_send(handle, destination, data, len);
270 /// Get a handle for a specific node.
271 /** This function returns a handle for the node with the given name.
273 * @param name The name of the node for which a handle is requested.
275 * @return A pointer to a meshlink::node which represents the requested node,
276 * or NULL if the requested node does not exist.
278 node *get_node(const char *name) {
279 return (node *)meshlink_get_node(handle, name);
282 /// Get a handle for our own node.
283 /** This function returns a handle for the local node.
285 * @return A pointer to a meshlink::node which represents the local node.
288 return (node *)meshlink_get_self(handle);
291 /// Get a list of all nodes.
292 /** This function returns a list with handles for all known nodes.
294 * @param nodes A pointer to an array of pointers to meshlink::node, which should be allocated by the application.
295 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
297 * @return The number of known nodes, or -1 in case of an error.
298 * This can be larger than nmemb, in which case not all nodes were stored in the nodes array.
300 node **get_all_nodes(node **nodes, size_t *nmemb) {
301 return (node **)meshlink_get_all_nodes(handle, (meshlink_node_t **)nodes, nmemb);
304 /// Sign data using the local node's MeshLink key.
305 /** This function signs data using the local node's MeshLink key.
306 * The generated signature can be securely verified by other nodes.
308 * @param data A pointer to a buffer containing the data to be signed.
309 * @param len The length of the data to be signed.
310 * @param signature A pointer to a buffer where the signature will be stored.
311 * @param siglen The size of the signature buffer. Will be changed after the call to match the size of the signature itself.
313 * @return This function returns true if the signature is valid, false otherwise.
315 bool sign(const void *data, size_t len, void *signature, size_t *siglen) {
316 return meshlink_sign(handle, data, len, signature, siglen);
319 /// Verify the signature generated by another node of a piece of data.
320 /** This function verifies the signature that another node generated for a piece of data.
322 * @param source A pointer to a meshlink_node_t describing the source of the signature.
323 * @param data A pointer to a buffer containing the data to be verified.
324 * @param len The length of the data to be verified.
325 * @param signature A pointer to a string containing the signature.
326 * @param siglen The size of the signature.
328 * @return This function returns true if the signature is valid, false otherwise.
330 bool verify(node *source, const void *data, size_t len, const void *signature, size_t siglen) {
331 return meshlink_verify(handle, source, data, len, signature, siglen);
334 /// Add an Address for the local node.
335 /** This function adds an Address for the local node, which will be used for invitation URLs.
337 * @param address A string containing the address, which can be either in numeric format or a hostname.
339 * @return This function returns true if the address was added, false otherwise.
341 bool add_address(const char *address) {
342 return meshlink_add_address(handle, address);
345 /** This function performs tries to discover the local node's external address
346 * by contacting the meshlink.io server. If a reverse lookup of the address works,
347 * the FQDN associated with the address will be returned.
349 * Please note that this is function only returns a single address,
350 * even if the local node might have more than one external address.
351 * In that case, there is no control over which address will be selected.
352 * Also note that if you have a dynamic IP address, or are behind carrier-grade NAT,
353 * there is no guarantee that the external address will be valid for an extended period of time.
355 * This function is blocking. It can take several seconds before it returns.
356 * There is no guarantee it will be able to resolve the external address.
357 * Failures might be because by temporary network outages.
359 * @return This function returns a pointer to a C string containing the discovered external address,
360 * or NULL if there was an error looking up the address.
361 * After get_external_address() returns, the application is free to overwrite or free this string.
363 bool get_external_address() {
364 return meshlink_get_external_address(handle);
367 /// Try to discover the external address for the local node, and add it to its list of addresses.
368 /** This function is equivalent to:
370 * mesh->add_address(mesh->get_external_address());
372 * Read the description of get_external_address() for the limitations of this function.
374 * @return This function returns true if the address was added, false otherwise.
376 bool add_external_address() {
377 return meshlink_add_external_address(handle);
380 /// Get the network port used by the local node.
381 /** This function returns the network port that the local node is listening on.
383 * @param mesh A handle which represents an instance of MeshLink.
385 * @return This function returns the port number, or -1 in case of an error.
388 return meshlink_get_port(handle);
391 /// Set the network port used by the local node.
392 /** This function sets the network port that the local node is listening on.
393 * It may only be called when the mesh is not running.
394 * If unsure, call stop() before calling this function.
395 * Also note that if your node is already part of a mesh with other nodes,
396 * that the other nodes may no longer be able to initiate connections to the local node,
397 * since they will try to connect to the previously configured port.
399 * @param port The port number to listen on. This must be between 0 and 65535.
400 * If the port is set to 0, then MeshLink will listen on a port
401 * that is randomly assigned by the operating system every time open() is called.
403 * @return This function returns true if the port was succesfully changed, false otherwise.
405 bool set_port(int port) {
406 return meshlink_set_port(handle, port);
409 /// Invite another node into the mesh.
410 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
411 * The generated invitation is a string containing a URL.
412 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
413 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
415 * @param name The name that the invitee will use in the mesh.
417 * @return This function returns a string that contains the invitation URL.
418 * The application should call free() after it has finished using the URL.
420 char *invite(const char *name) {
421 return meshlink_invite(handle, name);
424 /// Use an invitation to join a mesh.
425 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
426 * An invitation can only be used if the local node has never connected to other nodes before.
427 * After a succesfully accepted invitation, the name of the local node may have changed.
429 * This function may only be called on a mesh that has not been started yet and which is not already part of an existing mesh.
431 * This function is blocking. It can take several seconds before it returns.
432 * There is no guarantee it will perform a successful join.
433 * Failures might be caused by temporary network outages, or by the invitation having expired.
435 * @param invitation A string containing the invitation URL.
437 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
439 bool join(const char *invitation) {
440 return meshlink_join(handle, invitation);
443 /// Export the local node's key and addresses.
444 /** This function generates a string that contains the local node's public key and one or more IP addresses.
445 * The application can pass it in some way to another node, which can then import it,
446 * granting the local node access to the other node's mesh.
448 * @return This function returns a string that contains the exported key and addresses.
449 * The application should call free() after it has finished using this string.
452 return meshlink_export(handle);
455 /// Import another node's key and addresses.
456 /** This function accepts a string containing the exported public key and addresses of another node.
457 * By importing this data, the local node grants the other node access to its mesh.
459 * @param data A string containing the other node's exported key and addresses.
461 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
463 bool import_key(const char *data) {
464 return meshlink_import(handle, data);
467 /// Blacklist a node from the mesh.
468 /** This function causes the local node to blacklist another node.
469 * The local node will drop any existing connections to that node,
470 * and will not send data to it nor accept any data received from it any more.
472 * @param node A pointer to a meshlink::node describing the node to be blacklisted.
474 void blacklist(node *node) {
475 return meshlink_blacklist(handle, node);
478 /// Set the poll callback.
479 /** This functions sets the callback that is called whenever data can be sent to another node.
480 * The callback is run in MeshLink's own thread.
481 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
482 * to pass data to or from the application's thread.
483 * The callback should also not block itself and return as quickly as possible.
485 * @param channel A handle for the channel.
486 * @param cb A pointer to the function which will be called when data can be sent to another node.
487 * If a NULL pointer is given, the callback will be disabled.
489 void set_channel_poll_cb(channel *channel, channel_poll_cb_t cb) {
490 meshlink_set_channel_poll_cb(handle, channel, (meshlink_channel_poll_cb_t)cb);
493 /// Open a reliable stream channel to another node.
494 /** This function is called whenever a remote node wants to open a channel to the local node.
495 * The application then has to decide whether to accept or reject this channel.
497 * This function sets the channel poll callback to channel_poll_trampoline, which in turn
498 * calls channel_poll. To set a differnt, channel-specific poll callback, use set_channel_poll_cb.
500 * @param node The node to which this channel is being initiated.
501 * @param port The port number the peer wishes to connect to.
502 * @param cb A pointer to the function which will be called when the remote node sends data to the local node.
503 * @param data A pointer to a buffer containing data to already queue for sending.
504 * @param len The length of the data.
505 * @param flags A bitwise-or'd combination of flags that set the semantics for this channel.
507 * @return A handle for the channel, or NULL in case of an error.
509 channel *channel_open(node *node, uint16_t port, channel_receive_cb_t cb, const void *data, size_t len, uint32_t flags = channel::TCP) {
510 channel *ch = (channel *)meshlink_channel_open_ex(handle, node, port, (meshlink_channel_receive_cb_t)cb, data, len, flags);
511 meshlink_set_channel_poll_cb(handle, ch, &channel_poll_trampoline);
517 * Sets channel_receive_trampoline as cb, which in turn calls this->channel_receive( ... ).
519 channel *channel_open(node *node, uint16_t port, const void *data, size_t len, uint32_t flags = channel::TCP) {
520 channel *ch = (channel *)meshlink_channel_open_ex(handle, node, port, &channel_receive_trampoline, data, len, flags);
521 meshlink_set_channel_poll_cb(handle, ch, &channel_poll_trampoline);
525 /// Partially close a reliable stream channel.
526 /** This shuts down the read or write side of a channel, or both, without closing the handle.
527 * It can be used to inform the remote node that the local node has finished sending all data on the channel,
528 * but still allows waiting for incoming data from the remote node.
530 * @param channel A handle for the channel.
531 * @param direction Must be one of SHUT_RD, SHUT_WR or SHUT_RDWR.
533 void channel_shutdown(channel *channel, int direction) {
534 return meshlink_channel_shutdown(handle, channel, direction);
537 /// Close a reliable stream channel.
538 /** This informs the remote node that the local node has finished sending all data on the channel.
539 * It also causes the local node to stop accepting incoming data from the remote node.
540 * Afterwards, the channel handle is invalid and must not be used any more.
542 * @param channel A handle for the channel.
544 void channel_close(meshlink_channel_t *channel) {
545 return meshlink_channel_close(handle, channel);
548 /// Transmit data on a channel
549 /** This queues data to send to the remote node.
551 * @param channel A handle for the channel.
552 * @param data A pointer to a buffer containing data sent by the source.
553 * @param len The length of the data.
555 * @return The amount of data that was queued, which can be less than len, or a negative value in case of an error.
557 ssize_t channel_send(channel *channel, void *data, size_t len) {
558 return meshlink_channel_send(handle, channel, data, len);
561 /// Enable or disable zeroconf discovery of local peers
562 /** This controls whether zeroconf discovery using the Catta library will be
563 * enabled to search for peers on the local network. By default, it is enabled.
565 * @param enable Set to true to enable discovery, false to disable.
567 void enable_discovery(bool enable = true) {
568 meshlink_enable_discovery(handle, enable);
573 mesh(const mesh &) /* TODO: C++11: = delete */;
574 void operator=(const mesh &) /* TODO: C++11: = delete */ ;
576 /// static callback trampolines:
577 static void receive_trampoline(meshlink_handle_t *handle, meshlink_node_t *source, const void *data, size_t length) {
580 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
581 that->receive(static_cast<node *>(source), data, length);
584 static void node_status_trampoline(meshlink_handle_t *handle, meshlink_node_t *peer, bool reachable) {
587 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
588 that->node_status(static_cast<node *>(peer), reachable);
591 static void log_trampoline(meshlink_handle_t *handle, log_level_t level, const char *message) {
594 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
595 that->log(level, message);
598 static bool channel_accept_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, uint16_t port, const void *data, size_t len) {
601 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
602 bool accepted = that->channel_accept(static_cast<meshlink::channel *>(channel), port, data, len);
604 meshlink_set_channel_receive_cb(handle, channel, &channel_receive_trampoline);
605 meshlink_set_channel_poll_cb(handle, channel, &channel_poll_trampoline);
610 static void channel_receive_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, const void *data, size_t len) {
613 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
614 that->channel_receive(static_cast<meshlink::channel *>(channel), data, len);
617 static void channel_poll_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, size_t len) {
620 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
621 that->channel_poll(static_cast<meshlink::channel *>(channel), len);
624 meshlink_handle_t *handle;
627 static const char *strerror(errno_t err = meshlink_errno) {
628 return meshlink_strerror(err);
631 /// Destroy a MeshLink instance.
632 /** This function remove all configuration files of a MeshLink instance. It should only be called when the application
633 * does not have an open handle to this instance. Afterwards, a call to meshlink_open() will create a completely
636 * @param confbase The directory in which MeshLink stores its configuration files.
637 * After the function returns, the application is free to overwrite or free @a confbase @a.
639 * @return This function will return true if the MeshLink instance was succesfully destroyed, false otherwise.
641 static bool destroy(const char *confbase) {
642 return meshlink_destroy(confbase);