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
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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.
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17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
32 /// A handle for an instance of MeshLink.
33 typedef struct meshlink_handle meshlink_handle_t;
35 /// A handle for a MeshLink node.
36 typedef struct meshlink_node meshlink_node_t;
38 typedef struct meshlink_connection meshlink_connection_t;
40 /// Code of most recent error encountered.
42 MESHLINK_OK, ///< Everything is fine
43 MESHLINK_ENOMEM, ///< Out of memory
44 MESHLINK_ENOENT, ///< Node is not known
47 #ifndef MESHLINK_INTERNAL_H
49 struct meshlink_handle {
50 meshlink_errno_t meshlink_errno; ///< Code of the last encountered error.
51 const char *errstr; ///< Textual representation of most recent error encountered.
54 struct meshlink_node {
55 const char *name; ///< Textual name of this node.
56 void *priv; ///< Private pointer which the application can set at will.
59 struct meshlink_connection {
63 #endif // MESHLINK_INTERNAL_H
65 /// Get the text for the given MeshLink error code.
66 /** This function returns a pointer to the string containing the description of the given error code.
68 * @param errno An error code returned by MeshLink.
70 * @return A pointer to a string containing the description of the error code.
72 extern const char *meshlink_strerror(meshlink_errno_t errno);
74 /// Initialize MeshLink's configuration directory.
75 /** This function causes MeshLink to initialize its configuration directory,
76 * if it hasn't already been initialized.
77 * It only has to be run the first time the application starts,
78 * but it is not a problem if it is run more than once, as long as
79 * the arguments given are the same.
81 * This function does not start any network I/O yet. The application should
82 * first set callbacks, and then call meshlink_start().
84 * @param confbase The directory in which MeshLink will store its configuration files.
85 * @param name The name which this instance of the application will use in the mesh.
87 * @return This function will return true if MeshLink has succesfully set up its configuration files, false otherwise.
89 extern meshlink_handle_t *meshlink_open(const char *confbase, const char *name);
92 /** This function causes MeshLink to open network sockets, make outgoing connections, and
93 * create a new thread, which will handle all network I/O.
95 * @param mesh A handle which represents an instance of MeshLink.
97 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
99 extern bool meshlink_start(meshlink_handle_t *mesh);
102 /** This function causes MeshLink to disconnect from all other nodes,
103 * close all sockets, and shut down its own thread.
105 * @param mesh A handle which represents an instance of MeshLink.
107 extern void meshlink_stop(meshlink_handle_t *mesh);
109 /// Close the MeshLink handle.
110 /** This function calls meshlink_stop() if necessary,
111 * and frees all memory allocated by MeshLink.
112 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
114 * @param mesh A handle which represents an instance of MeshLink.
116 extern void meshlink_close(meshlink_handle_t *mesh);
118 /// A callback for receiving data from the mesh.
119 /** @param mesh A handle which represents an instance of MeshLink.
120 * @param source A pointer to a meshlink_node_t describing the source of the data.
121 * @param data A pointer to a buffer containing the data sent by the source.
122 * @param len The length of the received data.
124 typedef void (*meshlink_receive_cb_t)(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len);
126 /// Set the receive callback.
127 /** This functions sets the callback that is called whenever another node sends data to the local node.
128 * The callback is run in MeshLink's own thread.
129 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
130 * to hand the data over to the application's thread.
131 * The callback should also not block itself and return as quickly as possible.
133 * @param mesh A handle which represents an instance of MeshLink.
134 * @param cb A pointer to the function which will be called when another node sends data to the local node.
136 extern void meshlink_set_receive_cb(meshlink_handle_t *mesh, meshlink_receive_cb_t cb);
138 /// A callback reporting node status changes.
139 /** @param mesh A handle which represents an instance of MeshLink.
140 * @param node A pointer to a meshlink_node_t describing the node whose status changed.
141 * @param reachable True if the node is reachable, false otherwise.
143 typedef void (*meshlink_node_status_cb_t)(meshlink_handle_t *mesh, meshlink_node_t *node, bool reachable);
145 /// Set the node status callback.
146 /** This functions sets the callback that is called whenever another node's status changed.
147 * The callback is run in MeshLink's own thread.
148 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
149 * to hand the data over to the application's thread.
150 * The callback should also not block itself and return as quickly as possible.
152 * @param mesh A handle which represents an instance of MeshLink.
153 * @param cb A pointer to the function which will be called when another node's status changes.
155 extern void meshlink_set_node_status_cb(meshlink_handle_t *mesh, meshlink_node_status_cb_t cb);
157 /// Severity of log messages generated by MeshLink.
159 MESHLINK_DEBUG, ///< Internal debugging messages. Only useful during application development.
160 MESHLINK_INFO, ///< Informational messages.
161 MESHLINK_WARNING, ///< Warnings which might indicate problems, but which are not real errors.
162 MESHLINK_ERROR, ///< Errors which hamper correct functioning of MeshLink, without causing it to fail completely.
163 MESHLINK_CRITICAL, ///< Critical errors which cause MeshLink to fail completely.
164 } meshlink_log_level_t;
166 /// A callback for receiving log messages generated by MeshLink.
167 /** @param mesh A handle which represents an instance of MeshLink.
168 * @param level An enum describing the severity level of the message.
169 * @param text A pointer to a string containing the textual log message.
171 typedef void (*meshlink_log_cb_t)(meshlink_handle_t *mesh, meshlink_log_level_t level, const char *text);
173 /// Set the log callback.
174 /** This functions sets the callback that is called whenever MeshLink has some information to log.
175 * The callback is run in MeshLink's own thread.
176 * It is important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
177 * to hand the data over to the application's thread.
178 * The callback should also not block itself and return as quickly as possible.
180 * @param mesh A handle which represents an instance of MeshLink.
181 * @param level An enum describing the minimum severity level. Debugging information with a lower level will not trigger the callback.
182 * @param cb A pointer to the function which will be called when another node sends data to the local node.
184 extern void meshlink_set_log_cb(meshlink_handle_t *mesh, meshlink_log_level_t level, meshlink_log_cb_t cb);
186 /// Send data to another node.
187 /** This functions sends one packet of data to another node in the mesh.
188 * The packet is sent using UDP semantics, which means that
189 * the packet is sent as one unit and is received as one unit,
190 * and that there is no guarantee that the packet will arrive at the destination.
191 * The application should take care of getting an acknowledgement and retransmission if necessary.
193 * @param mesh A handle which represents an instance of MeshLink.
194 * @param destination A pointer to a meshlink_node_t describing the destination for the data.
195 * @param data A pointer to a buffer containing the data to be sent to the source.
196 * @param len The length of the data.
197 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
198 * A return value of true does not guarantee that the message will actually arrive at the destination.
200 extern bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, const void *data, unsigned int len);
202 /// Get a handle for a specific node.
203 /** This function returns a handle for the node with the given name.
205 * @param mesh A handle which represents an instance of MeshLink.
206 * @param name The name of the node for which a handle is requested.
208 * @return A pointer to a meshlink_node_t which represents the requested node,
209 * or NULL if the requested node does not exist.
211 extern meshlink_node_t *meshlink_get_node(meshlink_handle_t *mesh, const char *name);
213 /// Get a list of all nodes.
214 /** This function returns a list with handles for all known nodes.
216 * @param mesh A handle which represents an instance of MeshLink.
217 * @param nodes A pointer to an array of pointers to meshlink_node_t, which should be allocated by the application.
218 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
220 * @return The number of known nodes. This can be larger than nmemb, in which case not all nodes were stored in the nodes array.
222 extern size_t meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_t **nodes, size_t nmemb);
224 /// Sign data using the local node's MeshLink key.
225 /** This function signs data using the local node's MeshLink key.
226 * The generated signature can be securely verified by other nodes.
228 * @param mesh A handle which represents an instance of MeshLink.
229 * @param data A pointer to a buffer containing the data to be signed.
230 * @param len The length of the data to be signed.
232 * @return This function returns a pointer to a string containing the signature, or NULL in case of an error.
233 * The application should call free() after it has finished using the signature.
235 extern char *meshlink_sign(meshlink_handle_t *mesh, const char *data, size_t len);
237 /// Verify the signature generated by another node of a piece of data.
238 /** This function verifies the signature that another node generated for a piece of data.
240 * @param mesh A handle which represents an instance of MeshLink.
241 * @param source A pointer to a meshlink_node_t describing the source of the signature.
242 * @param data A pointer to a buffer containing the data to be verified.
243 * @param len The length of the data to be verified.
244 * @param signature A pointer to a string containing the signature.
246 * @return This function returns true if the signature is valid, false otherwise.
248 extern bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const char *data, size_t len, const char *signature);
250 /// Add an Address for the local node.
251 /** This function adds an Address for the local node, which will be used for invitation URLs.
253 * @param mesh A handle which represents an instance of MeshLink.
254 * @param address A string containing the address, which can be either in numeric format or a hostname.
256 * @return This function returns true if the address was added, false otherwise.
258 extern bool meshlink_add_address(meshlink_handle_t *mesh, const char *address);
260 /// Invite another node into the mesh.
261 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
262 * The generated invitation is a string containing a URL.
263 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
264 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
266 * @param mesh A handle which represents an instance of MeshLink.
267 * @param name The name that the invitee will use in the mesh.
269 * @return This function returns a string that contains the invitation URL.
270 * The application should call free() after it has finished using the URL.
272 extern char *meshlink_invite(meshlink_handle_t *mesh, const char *name);
274 /// Use an invitation to join a mesh.
275 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
276 * An invitation can only be used if the local node has never connected to other nodes before.
277 * After a succesfully accepted invitation, the name of the local node may have changed.
279 * @param mesh A handle which represents an instance of MeshLink.
280 * @param invitation A string containing the invitation URL.
282 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
284 extern bool meshlink_join(meshlink_handle_t *mesh, const char *invitation);
286 /// Export the local node's key and addresses.
287 /** This function generates a string that contains the local node's public key and one or more IP addresses.
288 * The application can pass it in some way to another node, which can then import it,
289 * granting the local node access to the other node's mesh.
291 * @param mesh A handle which represents an instance of MeshLink.
293 * @return This function returns a string that contains the exported key and addresses.
294 * The application should call free() after it has finished using this string.
296 extern char *meshlink_export(meshlink_handle_t *mesh);
298 /// Import another node's key and addresses.
299 /** This function accepts a string containing the exported public key and addresses of another node.
300 * By importing this data, the local node grants the other node access to its mesh.
302 * @param mesh A handle which represents an instance of MeshLink.
303 * @param data A string containing the other node's exported key and addresses.
305 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
307 extern bool meshlink_import(meshlink_handle_t *mesh, const char *data);
309 /// Blacklist a node from the mesh.
310 /** This function causes the local node to blacklist another node.
311 * The local node will drop any existing connections to that node,
312 * and will not send data to it nor accept any data received from it any more.
314 * @param mesh A handle which represents an instance of MeshLink.
315 * @param node A pointer to a meshlink_node_t describing the node to be blacklisted.
317 extern void meshlink_blacklist(meshlink_handle_t *mesh, meshlink_node_t *node);
319 /// Open a channel to destination node for reliable data delivery
320 extern meshlink_connection_t* meshlink_open_rchannel(meshlink_handle_t *mesh, meshlink_node_t *destination, uint16_t dport);