2 meshlink.h -- MeshLink 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.
26 /// A handle for an instance of MeshLink.
27 typedef struct meshlink_handle meshlink_handle_t;
29 /// A handle for a MeshLink node.
30 typedef struct meshlink_node meshlink_node_t;
32 /// Code of most recent error encountered.
34 MESHLINK_OK, // Everything is fine
35 MESHLINK_ENOMEM, // Out of memory
36 MESHLINK_ENOENT, // Node is not known
39 #ifndef MESHLINK_INTERNAL_H
41 struct meshlink_handle {
42 meshlink_errno_t errno; /// Code of the last encountered error.
43 const char *errstr; /// Textual representation of most recent error encountered.
46 struct meshlink_node {
47 const char *name; // Textual name of this node.
48 void *priv; // Private pointer which the application can set at will.
51 #endif // MESHLINK_INTERNAL_H
53 /// Get the text for the given MeshLink error code.
54 /** This function returns a pointer to the string containing the description of the given error code.
56 * @param errno An error code returned by MeshLink.
58 * @return A pointer to a string containing the description of the error code.
60 extern const char *meshlink_strerror(meshlink_errno_t errno);
62 /// Initialize MeshLink's configuration directory.
63 /** This function causes MeshLink to initialize its configuration directory,
64 * if it hasn't already been initialized.
65 * It only has to be run the first time the application starts,
66 * but it is not a problem if it is run more than once, as long as
67 * the arguments given are the same.
69 * @param confbase The directory in which MeshLink will store its configuration files.
70 * @param name The name which this instance of the application will use in the mesh.
72 * @return This function will return true if MeshLink has succesfully set up its configuration files, false otherwise.
74 extern meshlink_handle_t *meshlink_open(const char *confbase, const char *name);
77 /** This function causes MeshLink to create a new thread, which will
78 * handle all network I/O.
80 * @param confbase The directory in which MeshLink will store its configuration files.
82 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
84 extern bool meshlink_start(meshlink_handle_t *mesh);
87 /** This function causes MeshLink to disconnect from all other nodes,
88 * and shuts down its own thread.
90 * @param handle A handle which represents an instance of MeshLink.
92 extern void meshlink_stop(meshlink_handle_t *mesh);
94 /// Close the MeshLink handle.
95 /** This function calls meshlink_stop() if necessary,
96 * and frees all memory allocated by MeshLink.
97 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
99 * @param handle A handle which represents an instance of MeshLink.
101 extern void meshlink_close(meshlink_handle_t *mesh);
103 /// A callback for receiving data from the mesh.
104 /** @param handle A handle which represents an instance of MeshLink.
105 * @param source A pointer to a meshlink_node_t describing the source of the data.
106 * @param data A pointer to a buffer containing the data sent by the source.
107 * @param len The length of the received data.
109 typedef void (*meshlink_receive_cb_t)(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len);
111 /// Set the receive callback.
112 /** This functions sets the callback that is called whenever another node sends data to the local node.
113 * The callback is run in MeshLink's own thread.
114 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
115 * to hand the data over to the application's thread.
116 * The callback should also not block itself and return as quickly as possible.
118 * @param handle A handle which represents an instance of MeshLink.
119 * @param cb A pointer to the function which will be called when another node sends data to the local node.
121 extern void meshlink_set_receive_cb(meshlink_handle_t *mesh, meshlink_receive_cb_t cb);
123 /// A callback reporting node status changes.
124 /** @param handle A handle which represents an instance of MeshLink.
125 * @param node A pointer to a meshlink_node_t describing the node whose status changed.
126 * @param reachable True if the node is reachable, false otherwise.
128 typedef void (*meshlink_node_status_cb_t)(meshlink_handle_t *mesh, meshlink_node_t *node, bool reachable);
130 /// Set the node status callback.
131 /** This functions sets the callback that is called whenever another node's status changed.
132 * The callback is run in MeshLink's own thread.
133 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
134 * to hand the data over to the application's thread.
135 * The callback should also not block itself and return as quickly as possible.
137 * @param handle A handle which represents an instance of MeshLink.
138 * @param cb A pointer to the function which will be called when another node's status changes.
140 extern void meshlink_set_node_status_cb(meshlink_handle_t *mesh, meshlink_node_status_cb_t cb);
142 /// Severity of log messages generated by MeshLink.
144 MESHLINK_DEBUG, // Internal debugging messages. Only useful during application development.
145 MESHLINK_INFO, // Informational messages.
146 MESHLINK_WARNING, // Warnings which might indicate problems, but which are not real errors.
147 MESHLINK_ERROR, // Errors which hamper correct functioning of MeshLink, without causing it to fail completely.
148 MESHLINK_CRITICAL, // Critical errors which cause MeshLink to fail completely.
149 } meshlink_log_level_t;
151 /// A callback for receiving log messages generated by MeshLink.
152 /** @param handle A handle which represents an instance of MeshLink.
153 * @param level An enum describing the severity level of the message.
154 * @param text A pointer to a string containing the textual log message.
156 typedef void (*meshlink_log_cb_t)(meshlink_handle_t *mesh, meshlink_log_level_t level, const char *text);
158 /// Set the log callback.
159 /** This functions sets the callback that is called whenever MeshLink has some information to log.
160 * The callback is run in MeshLink's own thread.
161 * It is important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
162 * to hand the data over to the application's thread.
163 * The callback should also not block itself and return as quickly as possible.
165 * @param handle A handle which represents an instance of MeshLink.
166 * @param level An enum describing the minimum severity level. Debugging information with a lower level will not trigger the callback.
167 * @param cb A pointer to the function which will be called when another node sends data to the local node.
169 extern void meshlink_set_log_cb(meshlink_handle_t *mesh, meshlink_log_level_t level, meshlink_log_cb_t cb);
171 /// Send data to another node.
172 /** This functions sends one packet of data to another node in the mesh.
173 * The packet is sent using UDP semantics, which means that
174 * the packet is sent as one unit and is received as one unit,
175 * and that there is no guarantee that the packet will arrive at the destination.
176 * The application should take care of getting an acknowledgement and retransmission if necessary.
178 * @param handle A handle which represents an instance of MeshLink.
179 * @param destination A pointer to a meshlink_node_t describing the destination for the data.
180 * @param data A pointer to a buffer containing the data to be sent to the source.
181 * @param len The length of the data.
182 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
183 * A return value of true does not guarantee that the message will actually arrive at the destination.
185 extern bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, const void *data, unsigned int len);
187 /// Get a handle for a specific node.
188 /** This function returns a handle for the node with the given name.
190 * @param handle A handle which represents an instance of MeshLink.
191 * @param name The name of the node for which a handle is requested.
193 * @return A pointer to a meshlink_node_t which represents the requested node,
194 * or NULL if the requested node does not exist.
196 extern meshlink_node_t *meshlink_get_node(meshlink_handle_t *mesh, const char *name);
198 /// Get a list of all nodes.
199 /** This function returns a list with handles for all known nodes.
201 * @param handle A handle which represents an instance of MeshLink.
202 * @param nodes A pointer to an array of pointers to meshlink_node_t, which should be allocated by the application.
203 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
205 * @param return The number of known nodes. This can be larger than nmemb, in which case not all nodes were stored in the nodes array.
207 extern size_t meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_t **nodes, size_t nmemb);
209 /// Sign data using the local node's MeshLink key.
210 /** This function signs data using the local node's MeshLink key.
211 * The generated signature can be securely verified by other nodes.
213 * @param handle A handle which represents an instance of MeshLink.
214 * @param data A pointer to a buffer containing the data to be signed.
215 * @param len The length of the data to be signed.
217 * @return This function returns a pointer to a string containing the signature, or NULL in case of an error.
218 * The application should call free() after it has finished using the signature.
220 extern char *meshlink_sign(meshlink_handle_t *mesh, const char *data, size_t len);
222 /// Verify the signature generated by another node of a piece of data.
223 /** This function verifies the signature that another node generated for a piece of data.
225 * @param handle A handle which represents an instance of MeshLink.
226 * @param source A pointer to a meshlink_node_t describing the source of the signature.
227 * @param data A pointer to a buffer containing the data to be verified.
228 * @param len The length of the data to be verified.
229 * @param signature A pointer to a string containing the signature.
231 * @return This function returns true if the signature is valid, false otherwise.
233 extern bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const char *data, size_t len, const char *signature);
235 /// Invite another node into the mesh.
236 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
237 * The generated invitation is a string containing a URL.
238 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
239 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
241 * @param handle A handle which represents an instance of MeshLink.
242 * @param name The name that the invitee will use in the mesh.
244 * @return This function returns a string that contains the invitation URL.
245 * The application should call free() after it has finished using the URL.
247 extern char *meshlink_invite(meshlink_handle_t *mesh, const char *name);
249 /// Use an invitation to join a mesh.
250 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
251 * An invitation can only be used if the local node has never connected to other nodes before.
252 * After a succesfully accepted invitation, the name of the local node may have changed.
254 * @param handle A handle which represents an instance of MeshLink.
255 * @param invitation A string containing the invitation URL.
257 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
259 extern bool meshlink_join(meshlink_handle_t *mesh, const char *invitation);
261 /// Export the local node's key and addresses.
262 /** This function generates a string that contains the local node's public key and one or more IP addresses.
263 * The application can pass it in some way to another node, which can then import it,
264 * granting the local node access to the other node's mesh.
266 * @param handle A handle which represents an instance of MeshLink.
268 * @return This function returns a string that contains the exported key and addresses.
269 * The application should call free() after it has finished using this string.
271 extern char *meshlink_export(meshlink_handle_t *mesh);
273 /// Import another node's key and addresses.
274 /** This function accepts a string containing the exported public key and addresses of another node.
275 * By importing this data, the local node grants the other node access to its mesh.
277 * @param handle A handle which represents an instance of MeshLink.
278 * @param data A string containing the other node's exported key and addresses.
280 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
282 extern bool meshlink_import(meshlink_handle_t *mesh, const char *data);
284 /// Blacklist a node from the mesh.
285 /** This function causes the local node to blacklist another node.
286 * The local node will drop any existing connections to that node,
287 * and will not send data to it nor accept any data received from it any more.
289 * @param handle A handle which represents an instance of MeshLink.
290 * @param node A pointer to a meshlink_node_t describing the node to be blacklisted.
292 extern void meshlink_blacklist(meshlink_handle_t *mesh, meshlink_node_t *node);