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);
150 mesh(const char *confbase, const char *name, const char *appname, dev_class_t devclass) {
151 open(confbase, name, appname, devclass);
154 /// Close the MeshLink handle.
155 /** This function calls meshlink_stop() if necessary,
156 * and frees all memory allocated by MeshLink.
157 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
162 meshlink_close(handle);
168 /** instead of registerin callbacks you derive your own class and overwrite the following abstract member functions.
169 * These functions are run in MeshLink's own thread.
170 * It is therefore important that these functions use apprioriate methods (queues, pipes, locking, etc.)
171 * to hand the data over to the application's thread.
172 * These functions should also not block itself and return as quickly as possible.
173 * The default member functions are no-ops, so you are not required to overwrite all these member functions
176 /// This function is called whenever another node sends data to the local node.
177 virtual void receive(node *source, const void *data, size_t length) { /* do nothing */ }
179 /// This functions is called whenever another node's status changed.
180 virtual void node_status(node *peer, bool reachable) { /* do nothing */ }
182 /// This functions is called whenever MeshLink has some information to log.
183 virtual void log(log_level_t level, const char *message) { /* do nothing */ }
185 /// This functions is called whenever another node attemps to open a channel to the local node.
187 * If the channel is accepted, the poll_callback will be set to channel_poll and can be
188 * changed using set_channel_poll_cb(). Likewise, the receive callback is set to
191 * The function is run in MeshLink's own thread.
192 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
193 * to pass data to or from the application's thread.
194 * The callback should also not block itself and return as quickly as possible.
196 * @param channel A handle for the incoming channel.
197 * @param port The port number the peer wishes to connect to.
198 * @param data A pointer to a buffer containing data already received. (Not yet used.)
199 * @param len The length of the data. (Not yet used.)
201 * @return This function should return true if the application accepts the incoming channel, false otherwise.
202 * If returning false, the channel is invalid and may not be used anymore.
204 virtual bool channel_accept(channel *channel, uint16_t port, const void *data, size_t len) {
205 /* by default reject all channels */
209 /// This function is called by Meshlink for receiving data from a channel.
211 * The function is run in MeshLink's own thread.
212 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
213 * to pass data to or from the application's thread.
214 * The callback should also not block itself and return as quickly as possible.
216 * @param channel A handle for the channel.
217 * @param data A pointer to a buffer containing data sent by the source.
218 * @param len The length of the data.
220 virtual void channel_receive(channel *channel, const void *data, size_t len) { /* do nothing */ }
222 /// This function is called by Meshlink when data can be send on a channel.
224 * The function is run in MeshLink's own thread.
225 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
226 * to pass data to or from the application's thread.
228 * The callback should also not block itself and return as quickly as possible.
229 * @param channel A handle for the channel.
230 * @param len The maximum length of data that is guaranteed to be accepted by a call to channel_send().
232 virtual void channel_poll(channel *channel, size_t len) { /* do nothing */ }
235 /** This function causes MeshLink to open network sockets, make outgoing connections, and
236 * create a new thread, which will handle all network I/O.
238 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
241 meshlink_set_receive_cb(handle, &receive_trampoline);
242 meshlink_set_node_status_cb(handle, &node_status_trampoline);
243 meshlink_set_log_cb(handle, MESHLINK_DEBUG, &log_trampoline);
244 meshlink_set_channel_accept_cb(handle, &channel_accept_trampoline);
245 return meshlink_start(handle);
249 /** This function causes MeshLink to disconnect from all other nodes,
250 * close all sockets, and shut down its own thread.
253 meshlink_stop(handle);
256 /// Send data to another node.
257 /** This functions sends one packet of data to another node in the mesh.
258 * The packet is sent using UDP semantics, which means that
259 * the packet is sent as one unit and is received as one unit,
260 * and that there is no guarantee that the packet will arrive at the destination.
261 * The application should take care of getting an acknowledgement and retransmission if necessary.
263 * @param destination A pointer to a meshlink::node describing the destination for the data.
264 * @param data A pointer to a buffer containing the data to be sent to the source.
265 * @param len The length of the data.
266 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
267 * A return value of true does not guarantee that the message will actually arrive at the destination.
269 bool send(node *destination, const void *data, unsigned int len) {
270 return meshlink_send(handle, destination, data, len);
273 /// Get a handle for a specific node.
274 /** This function returns a handle for the node with the given name.
276 * @param name The name of the node for which a handle is requested.
278 * @return A pointer to a meshlink::node which represents the requested node,
279 * or NULL if the requested node does not exist.
281 node *get_node(const char *name) {
282 return (node *)meshlink_get_node(handle, name);
285 /// Get a handle for our own node.
286 /** This function returns a handle for the local node.
288 * @return A pointer to a meshlink::node which represents the local node.
291 return (node *)meshlink_get_self(handle);
294 /// Get a list of all nodes.
295 /** This function returns a list with handles for all known nodes.
297 * @param nodes A pointer to an array of pointers to meshlink::node, which should be allocated by the application.
298 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
300 * @return The number of known nodes, or -1 in case of an error.
301 * This can be larger than nmemb, in which case not all nodes were stored in the nodes array.
303 node **get_all_nodes(node **nodes, size_t *nmemb) {
304 return (node **)meshlink_get_all_nodes(handle, (meshlink_node_t **)nodes, nmemb);
307 /// Sign data using the local node's MeshLink key.
308 /** This function signs data using the local node's MeshLink key.
309 * The generated signature can be securely verified by other nodes.
311 * @param data A pointer to a buffer containing the data to be signed.
312 * @param len The length of the data to be signed.
313 * @param signature A pointer to a buffer where the signature will be stored.
314 * @param siglen The size of the signature buffer. Will be changed after the call to match the size of the signature itself.
316 * @return This function returns true if the signature is valid, false otherwise.
318 bool sign(const void *data, size_t len, void *signature, size_t *siglen) {
319 return meshlink_sign(handle, data, len, signature, siglen);
322 /// Verify the signature generated by another node of a piece of data.
323 /** This function verifies the signature that another node generated for a piece of data.
325 * @param source A pointer to a meshlink_node_t describing the source of the signature.
326 * @param data A pointer to a buffer containing the data to be verified.
327 * @param len The length of the data to be verified.
328 * @param signature A pointer to a string containing the signature.
329 * @param siglen The size of the signature.
331 * @return This function returns true if the signature is valid, false otherwise.
333 bool verify(node *source, const void *data, size_t len, const void *signature, size_t siglen) {
334 return meshlink_verify(handle, source, data, len, signature, siglen);
337 /// Add an Address for the local node.
338 /** This function adds an Address for the local node, which will be used for invitation URLs.
340 * @param address A string containing the address, which can be either in numeric format or a hostname.
342 * @return This function returns true if the address was added, false otherwise.
344 bool add_address(const char *address) {
345 return meshlink_add_address(handle, address);
348 /** This function performs tries to discover the local node's external address
349 * by contacting the meshlink.io server. If a reverse lookup of the address works,
350 * the FQDN associated with the address will be returned.
352 * Please note that this is function only returns a single address,
353 * even if the local node might have more than one external address.
354 * In that case, there is no control over which address will be selected.
355 * Also note that if you have a dynamic IP address, or are behind carrier-grade NAT,
356 * there is no guarantee that the external address will be valid for an extended period of time.
358 * This function is blocking. It can take several seconds before it returns.
359 * There is no guarantee it will be able to resolve the external address.
360 * Failures might be because by temporary network outages.
362 * @return This function returns a pointer to a C string containing the discovered external address,
363 * or NULL if there was an error looking up the address.
364 * After get_external_address() returns, the application is free to overwrite or free this string.
366 bool get_external_address() {
367 return meshlink_get_external_address(handle);
370 /// Try to discover the external address for the local node, and add it to its list of addresses.
371 /** This function is equivalent to:
373 * mesh->add_address(mesh->get_external_address());
375 * Read the description of get_external_address() for the limitations of this function.
377 * @return This function returns true if the address was added, false otherwise.
379 bool add_external_address() {
380 return meshlink_add_external_address(handle);
383 /// Get the network port used by the local node.
384 /** This function returns the network port that the local node is listening on.
386 * @param mesh A handle which represents an instance of MeshLink.
388 * @return This function returns the port number, or -1 in case of an error.
391 return meshlink_get_port(handle);
394 /// Set the network port used by the local node.
395 /** This function sets the network port that the local node is listening on.
396 * It may only be called when the mesh is not running.
397 * If unsure, call stop() before calling this function.
398 * Also note that if your node is already part of a mesh with other nodes,
399 * that the other nodes may no longer be able to initiate connections to the local node,
400 * since they will try to connect to the previously configured port.
402 * @param port The port number to listen on. This must be between 0 and 65535.
403 * If the port is set to 0, then MeshLink will listen on a port
404 * that is randomly assigned by the operating system every time open() is called.
406 * @return This function returns true if the port was succesfully changed, false otherwise.
408 bool set_port(int port) {
409 return meshlink_set_port(handle, port);
412 /// Invite another node into the mesh.
413 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
414 * The generated invitation is a string containing a URL.
415 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
416 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
418 * @param name The name that the invitee will use in the mesh.
420 * @return This function returns a string that contains the invitation URL.
421 * The application should call free() after it has finished using the URL.
423 char *invite(const char *name) {
424 return meshlink_invite(handle, name);
427 /// Use an invitation to join a mesh.
428 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
429 * An invitation can only be used if the local node has never connected to other nodes before.
430 * After a succesfully accepted invitation, the name of the local node may have changed.
432 * 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.
434 * This function is blocking. It can take several seconds before it returns.
435 * There is no guarantee it will perform a successful join.
436 * Failures might be caused by temporary network outages, or by the invitation having expired.
438 * @param invitation A string containing the invitation URL.
440 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
442 bool join(const char *invitation) {
443 return meshlink_join(handle, invitation);
446 /// Export the local node's key and addresses.
447 /** This function generates a string that contains the local node's public key and one or more IP addresses.
448 * The application can pass it in some way to another node, which can then import it,
449 * granting the local node access to the other node's mesh.
451 * @return This function returns a string that contains the exported key and addresses.
452 * The application should call free() after it has finished using this string.
455 return meshlink_export(handle);
458 /// Import another node's key and addresses.
459 /** This function accepts a string containing the exported public key and addresses of another node.
460 * By importing this data, the local node grants the other node access to its mesh.
462 * @param data A string containing the other node's exported key and addresses.
464 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
466 bool import_key(const char *data) {
467 return meshlink_import(handle, data);
470 /// Blacklist a node from the mesh.
471 /** This function causes the local node to blacklist another node.
472 * The local node will drop any existing connections to that node,
473 * and will not send data to it nor accept any data received from it any more.
475 * @param node A pointer to a meshlink::node describing the node to be blacklisted.
477 void blacklist(node *node) {
478 return meshlink_blacklist(handle, node);
481 /// Set the poll callback.
482 /** This functions sets the callback that is called whenever data can be sent to another node.
483 * The callback is run in MeshLink's own thread.
484 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
485 * to pass data to or from the application's thread.
486 * The callback should also not block itself and return as quickly as possible.
488 * @param channel A handle for the channel.
489 * @param cb A pointer to the function which will be called when data can be sent to another node.
490 * If a NULL pointer is given, the callback will be disabled.
492 void set_channel_poll_cb(channel *channel, channel_poll_cb_t cb) {
493 meshlink_set_channel_poll_cb(handle, channel, (meshlink_channel_poll_cb_t)cb);
496 /// Open a reliable stream channel to another node.
497 /** This function is called whenever a remote node wants to open a channel to the local node.
498 * The application then has to decide whether to accept or reject this channel.
500 * This function sets the channel poll callback to channel_poll_trampoline, which in turn
501 * calls channel_poll. To set a differnt, channel-specific poll callback, use set_channel_poll_cb.
503 * @param node The node to which this channel is being initiated.
504 * @param port The port number the peer wishes to connect to.
505 * @param cb A pointer to the function which will be called when the remote node sends data to the local node.
506 * @param data A pointer to a buffer containing data to already queue for sending.
507 * @param len The length of the data.
508 * @param flags A bitwise-or'd combination of flags that set the semantics for this channel.
510 * @return A handle for the channel, or NULL in case of an error.
512 channel *channel_open(node *node, uint16_t port, channel_receive_cb_t cb, const void *data, size_t len, uint32_t flags = channel::TCP) {
513 channel *ch = (channel *)meshlink_channel_open_ex(handle, node, port, (meshlink_channel_receive_cb_t)cb, data, len, flags);
514 meshlink_set_channel_poll_cb(handle, ch, &channel_poll_trampoline);
520 * Sets channel_receive_trampoline as cb, which in turn calls this->channel_receive( ... ).
522 channel *channel_open(node *node, uint16_t port, const void *data, size_t len, uint32_t flags = channel::TCP) {
523 channel *ch = (channel *)meshlink_channel_open_ex(handle, node, port, &channel_receive_trampoline, data, len, flags);
524 meshlink_set_channel_poll_cb(handle, ch, &channel_poll_trampoline);
528 /// Partially close a reliable stream channel.
529 /** This shuts down the read or write side of a channel, or both, without closing the handle.
530 * It can be used to inform the remote node that the local node has finished sending all data on the channel,
531 * but still allows waiting for incoming data from the remote node.
533 * @param channel A handle for the channel.
534 * @param direction Must be one of SHUT_RD, SHUT_WR or SHUT_RDWR.
536 void channel_shutdown(channel *channel, int direction) {
537 return meshlink_channel_shutdown(handle, channel, direction);
540 /// Close a reliable stream channel.
541 /** This informs the remote node that the local node has finished sending all data on the channel.
542 * It also causes the local node to stop accepting incoming data from the remote node.
543 * Afterwards, the channel handle is invalid and must not be used any more.
545 * @param channel A handle for the channel.
547 void channel_close(meshlink_channel_t *channel) {
548 return meshlink_channel_close(handle, channel);
551 /// Transmit data on a channel
552 /** This queues data to send to the remote node.
554 * @param channel A handle for the channel.
555 * @param data A pointer to a buffer containing data sent by the source.
556 * @param len The length of the data.
558 * @return The amount of data that was queued, which can be less than len, or a negative value in case of an error.
560 ssize_t channel_send(channel *channel, void *data, size_t len) {
561 return meshlink_channel_send(handle, channel, data, len);
564 /// Enable or disable zeroconf discovery of local peers
565 /** This controls whether zeroconf discovery using the Catta library will be
566 * enabled to search for peers on the local network. By default, it is enabled.
568 * @param enable Set to true to enable discovery, false to disable.
570 void enable_discovery(bool enable = true) {
571 meshlink_enable_discovery(handle, enable);
576 mesh(const mesh &) /* TODO: C++11: = delete */;
577 void operator=(const mesh &) /* TODO: C++11: = delete */ ;
579 /// static callback trampolines:
580 static void receive_trampoline(meshlink_handle_t *handle, meshlink_node_t *source, const void *data, size_t length) {
581 if(!(handle->priv)) {
585 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
586 that->receive(static_cast<node *>(source), data, length);
589 static void node_status_trampoline(meshlink_handle_t *handle, meshlink_node_t *peer, bool reachable) {
590 if(!(handle->priv)) {
594 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
595 that->node_status(static_cast<node *>(peer), reachable);
598 static void log_trampoline(meshlink_handle_t *handle, log_level_t level, const char *message) {
599 if(!(handle->priv)) {
603 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
604 that->log(level, message);
607 static bool channel_accept_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, uint16_t port, const void *data, size_t len) {
608 if(!(handle->priv)) {
612 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
613 bool accepted = that->channel_accept(static_cast<meshlink::channel *>(channel), port, data, len);
616 meshlink_set_channel_receive_cb(handle, channel, &channel_receive_trampoline);
617 meshlink_set_channel_poll_cb(handle, channel, &channel_poll_trampoline);
623 static void channel_receive_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, const void *data, size_t len) {
624 if(!(handle->priv)) {
628 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
629 that->channel_receive(static_cast<meshlink::channel *>(channel), data, len);
632 static void channel_poll_trampoline(meshlink_handle_t *handle, meshlink_channel *channel, size_t len) {
633 if(!(handle->priv)) {
637 meshlink::mesh *that = static_cast<mesh *>(handle->priv);
638 that->channel_poll(static_cast<meshlink::channel *>(channel), len);
641 meshlink_handle_t *handle;
644 static inline const char *strerror(errno_t err = meshlink_errno) {
645 return meshlink_strerror(err);
648 /// Destroy a MeshLink instance.
649 /** This function remove all configuration files of a MeshLink instance. It should only be called when the application
650 * does not have an open handle to this instance. Afterwards, a call to meshlink_open() will create a completely
653 * @param confbase The directory in which MeshLink stores its configuration files.
654 * After the function returns, the application is free to overwrite or free @a confbase @a.
656 * @return This function will return true if the MeshLink instance was succesfully destroyed, false otherwise.
658 static inline bool destroy(const char *confbase) {
659 return meshlink_destroy(confbase);