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.
25 #ifndef MESHLINK_INTERNAL_H
27 /// A handle for an instance of MeshLink.
28 typedef struct meshlink_handle meshlink_handle_t;
30 /// A handle for a MeshLink node.
31 typedef struct meshlink_node {
35 #endif // MESHLINK_INTERNAL_H
37 /// Code of most recent error encountered.
39 MESHLINK_OK, // Everything is fine
40 MESHLINK_ENOMEM, // Out of memory
41 MESHLINK_ENOENT, // Node is not known
44 extern meshlink_errno_t meshlink_errno;
46 /// Textual representation of most recent error encountered.
47 const char *meshlink_errstr;
49 /// Get the text for the given MeshLink error code.
50 /** This function returns a pointer to the string containing the description of the given error code.
52 * @param errno An error code returned by MeshLink.
54 * @return A pointer to a string containing the description of the error code.
56 extern const char *meshlink_strerror(meshlink_errno_t errno);
58 /// Initialize MeshLink's configuration directory.
59 /** This function causes MeshLink to initialize its configuration directory,
60 * if it hasn't already been initialized.
61 * It only has to be run the first time the application starts,
62 * but it is not a problem if it is run more than once, as long as
63 * the arguments given are the same.
65 * @param confbase The directory in which MeshLink will store its configuration files.
66 * @param name The name which this instance of the application will use in the mesh.
68 * @return This function will return true if MeshLink has succesfully set up its configuration files, false otherwise.
70 extern meshlink_handle_t *meshlink_open(const char *confbase, const char *name);
73 /** This function causes MeshLink to create a new thread, which will
74 * handle all network I/O.
76 * @param confbase The directory in which MeshLink will store its configuration files.
78 * @return This function will return true if MeshLink has succesfully started its thread, false otherwise.
80 extern bool meshlink_start(meshlink_handle_t *handle);
83 /** This function causes MeshLink to disconnect from all other nodes,
84 * and shuts down its own thread.
86 * @param handle A handle which represents an instance of MeshLink.
88 extern void meshlink_stop(meshlink_handle_t *handle);
90 /// Close the MeshLink handle.
91 /** This function calls meshlink_stop() if necessary,
92 * and frees all memory allocated by MeshLink.
93 * Afterwards, the handle and any pointers to a struct meshlink_node are invalid.
95 * @param handle A handle which represents an instance of MeshLink.
97 extern void meshlink_close(meshlink_handle_t *handle);
99 /// A callback for receiving data from the mesh.
100 /** @param handle A handle which represents an instance of MeshLink.
101 * @param source A pointer to a meshlink_node_t describing the source of the data.
102 * @param data A pointer to a buffer containing the data sent by the source.
103 * @param len The length of the received data.
105 typedef void (*meshlink_receive_cb_t)(meshlink_handle_t *handle, meshlink_node_t *source, const void *data, size_t len);
107 /// Set the receive callback.
108 /** This functions sets the callback that is called whenever another node sends data to the local node.
109 * The callback is run in MeshLink's own thread.
110 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
111 * to hand the data over to the application's thread.
112 * The callback should also not block itself and return as quickly as possible.
114 * @param handle A handle which represents an instance of MeshLink.
115 * @param cb A pointer to the function which will be called when another node sends data to the local node.
117 void meshlink_set_receive_cb(meshlink_handle_t *handle, meshlink_receive_cb_t cb);
119 /// Send data to another node.
120 /** This functions sends one packet of data to another node in the mesh.
121 * The packet is sent using UDP semantics, which means that
122 * the packet is sent as one unit and is received as one unit,
123 * and that there is no guarantee that the packet will arrive at the destination.
124 * The application should take care of getting an acknowledgement and retransmission if necessary.
126 * @param handle A handle which represents an instance of MeshLink.
127 * @param destination A pointer to a meshlink_node_t describing the destination for the data.
128 * @param data A pointer to a buffer containing the data to be sent to the source.
129 * @param len The length of the data.
130 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
131 * A return value of true does not guarantee that the message will actually arrive at the destination.
133 extern bool meshlink_send(meshlink_handle_t *handle, meshlink_node_t *destination, const void *data, unsigned int len);
135 /// Get a handle for a specific node.
136 /** This function returns a handle for the node with the given name.
138 * @param handle A handle which represents an instance of MeshLink.
139 * @param name The name of the node for which a handle is requested.
141 * @return A pointer to a meshlink_node_t which represents the requested node,
142 * or NULL if the requested node does not exist.
144 extern meshlink_node_t *meshlink_get_node(meshlink_handle_t *handle, const char *name);
146 /// Get a list of all nodes.
147 /** This function returns a list with handles for all known nodes.
149 * @param handle A handle which represents an instance of MeshLink.
150 * @param nodes A pointer to an array of pointers to meshlink_node_t, which should be allocated by the application.
151 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
153 * @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.
155 extern size_t meshlink_get_all_nodes(meshlink_handle_t *handle, meshlink_node_t **nodes, size_t nmemb);
157 /// Sign data using the local node's MeshLink key.
158 /** This function signs data using the local node's MeshLink key.
159 * The generated signature can be securely verified by other nodes.
161 * @param handle A handle which represents an instance of MeshLink.
162 * @param data A pointer to a buffer containing the data to be signed.
163 * @param len The length of the data to be signed.
165 * @return This function returns a pointer to a string containing the signature, or NULL in case of an error.
166 * The application should call free() after it has finished using the signature.
168 extern char *meshlink_sign(meshlink_handle_t *handle, const char *data, size_t len);
170 /// Verify the signature generated by another node of a piece of data.
171 /** This function verifies the signature that another node generated for a piece of data.
173 * @param handle A handle which represents an instance of MeshLink.
174 * @param source A pointer to a meshlink_node_t describing the source of the signature.
175 * @param data A pointer to a buffer containing the data to be verified.
176 * @param len The length of the data to be verified.
177 * @param signature A pointer to a string containing the signature.
179 * @return This function returns true if the signature is valid, false otherwise.
181 extern bool meshlink_verify(meshlink_handle_t *handle, meshlink_node_t *source, const char *data, size_t len, const char *signature);
183 /// Invite another node into the mesh.
184 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
185 * The generated invitation is a string containing a URL.
186 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
187 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
189 * @param handle A handle which represents an instance of MeshLink.
190 * @param name The name that the invitee will use in the mesh.
192 * @return This function returns a string that contains the invitation URL.
193 * The application should call free() after it has finished using the URL.
195 extern char *meshlink_invite(meshlink_handle_t *handle, const char *name);
197 /// Use an invitation to join a mesh.
198 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
199 * An invitation can only be used if the local node has never connected to other nodes before.
200 * After a succesfully accepted invitation, the name of the local node may have changed.
202 * @param handle A handle which represents an instance of MeshLink.
203 * @param invitation A string containing the invitation URL.
205 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
207 extern bool meshlink_join(meshlink_handle_t *handle, const char *invitation);
209 /// Export the local node's key and addresses.
210 /** This function generates a string that contains the local node's public key and one or more IP addresses.
211 * The application can pass it in some way to another node, which can then import it,
212 * granting the local node access to the other node's mesh.
214 * @param handle A handle which represents an instance of MeshLink.
216 * @return This function returns a string that contains the exported key and addresses.
217 * The application should call free() after it has finished using this string.
219 extern char *meshlink_export(meshlink_handle_t *handle);
221 /// Import another node's key and addresses.
222 /** This function accepts a string containing the exported public key and addresses of another node.
223 * By importing this data, the local node grants the other node access to its mesh.
225 * @param handle A handle which represents an instance of MeshLink.
226 * @param data A string containing the other node's exported key and addresses.
228 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
230 extern bool meshlink_import(meshlink_handle_t *handle, const char *data);
232 /// Blacklist a node from the mesh.
233 /** This function causes the local node to blacklist another node.
234 * The local node will drop any existing connections to that node,
235 * and will not send data to it nor accept any data received from it any more.
237 * @param handle A handle which represents an instance of MeshLink.
238 * @param node A pointer to a meshlink_node_t describing the node to be blacklisted.
240 extern void meshlink_blacklist(meshlink_handle_t *handle, meshlink_node_t *node);