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.
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17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
25 /// A handle for an instance of MeshLink.
26 typedef struct meshlink_handle meshlink_handle_t;
28 /// A handle for a MeshLink node.
29 typedef struct meshlink_node meshlink_node_t;
31 /// Initialize MeshLink's configuration directory.
32 /** This function causes MeshLink to initialize its configuration directory,
33 * if it hasn't already been initialized.
34 * It only has to be run the first time the application starts,
35 * but it is not a problem if it is run more than once, as long as
36 * the arguments given are the same.
38 * @param confbase The directory in which MeshLink will store its configuration files.
39 * @param name The name which this instance of the application will use in the mesh.
40 * @return This function will return true if MeshLink has succesfully set up its configuration files, false otherwise.
42 extern bool meshlink_setup(const char *confbase, const char *name);
45 /** This function causes MeshLink to create a new thread, which will
46 * handle all network I/O.
48 * @param confbase The directory in which MeshLink will store its configuration files.
49 * @return A handle which represents this instance of MeshLink,
50 * or NULL in case of an error.
52 extern meshlink_handle_t *meshlink_start(const char *confbase);
55 /** This function causes MeshLink to disconnect from all other nodes,
56 * and shuts down its own thread. Afterwards, the handle and any
57 * pointers to a struct meshlink_node are invalid.
59 * @param handle A handle which represents an instance of MeshLink.
61 extern void meshlink_stop(meshlink_handle *handle);
63 /// A callback for receiving data from the mesh.
64 /** @param handle A handle which represents an instance of MeshLink.
65 * @param source A pointer to a meshlink_node_t describing the source of the data.
66 * @param data A pointer to a buffer containing the data sent by the source.
67 * @param len The length of the received data.
69 typedef void (*meshlink_receive_cb_t)(meshlink_handle_t *handle, meshlink_node_t *source, const void *data, size_t len);
71 /// Set the receive callback.
72 /** This functions sets the callback that is called whenever another node sends data to the local node.
73 * The callback is run in MeshLink's own thread.
74 * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.)
75 * to hand the data over to the application's thread.
76 * The callback should also not block itself and return as quickly as possible.
78 * @param handle A handle which represents an instance of MeshLink.
79 * @param cb A pointer to the function which will be called when another node sends data to the local node.
81 void meshlink_set_receive_cb(meshlink_handle_t *handle, meshlink_receive_cb_t cb);
83 /// Send data to another node.
84 /** This functions sends one packet of data to another node in the mesh.
85 * The packet is sent using UDP semantics, which means that
86 * the packet is sent as one unit and is received as one unit,
87 * and that there is no guarantee that the packet will arrive at the destination.
88 * The application should take care of getting an acknowledgement and retransmission if necessary.
90 * @param handle A handle which represents an instance of MeshLink.
91 * @param destination A pointer to a meshlink_node_t describing the destination for the data.
92 * @param data A pointer to a buffer containing the data to be sent to the source.
93 * @param len The length of the data.
94 * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise.
95 * A return value of true does not guarantee that the message will actually arrive at the destination.
97 extern bool meshlink_send(meshlink_handle_t *handle, meshlink_node_t *destination, const void *data, unsigned int len);
99 /// Get a handle for a specific node.
100 /** This function returns a handle for the node with the given name.
102 * @param handle A handle which represents an instance of MeshLink.
103 * @param name The name of the node for which a handle is requested.
105 * @return A pointer to a meshlink_node_t which represents the requested node,
106 * or NULL if the requested node does not exist.
108 extern meshlink_node_t *meshlink_get_node(meshlink_handle_t *handle, const char *name);
110 /// Get a list of all nodes.
111 /** This function returns a list with handles for all known nodes.
113 * @param handle A handle which represents an instance of MeshLink.
114 * @param nodes A pointer to an array of pointers to meshlink_node_t, which should be allocated by the application.
115 * @param nmemb The maximum number of pointers that can be stored in the nodes array.
117 * @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.
119 extern size_t meshlink_get_all_nodes(meshlink_handle_t *handle, meshlink_node_t **nodes, size_t nmemb);
121 /// Sign data using the local node's MeshLink key.
122 /** This function signs data using the local node's MeshLink key.
123 * The generated signature can be securely verified by other nodes.
125 * @param handle A handle which represents an instance of MeshLink.
126 * @param data A pointer to a buffer containing the data to be signed.
127 * @param len The length of the data to be signed.
129 * @return This function returns a pointer to a string containing the signature, or NULL in case of an error.
130 * The application should call free() after it has finished using the signature.
132 extern char *meshlink_sign(meshlink_handle_t *handle, const char *data, size_t len);
134 /// Verify the signature generated by another node of a piece of data.
135 /** This function verifies the signature that another node generated for a piece of data.
137 * @param handle A handle which represents an instance of MeshLink.
138 * @param source A pointer to a meshlink_node_t describing the source of the signature.
139 * @param data A pointer to a buffer containing the data to be verified.
140 * @param len The length of the data to be verified.
141 * @param signature A pointer to a string containing the signature.
143 * @return This function returns true if the signature is valid, false otherwise.
145 extern bool meshlink_verify(meshlink_handle_t *handle, meshlink_node_t *source, const char *data, size_t len, const char *signature);
147 /// Invite another node into the mesh.
148 /** This function generates an invitation that can be used by another node to join the same mesh as the local node.
149 * The generated invitation is a string containing a URL.
150 * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL.
151 * The URL can only be used once, after the user has joined the mesh the URL is no longer valid.
153 * @param handle A handle which represents an instance of MeshLink.
154 * @param name The name that the invitee will use in the mesh.
156 * @return This function returns a string that contains the invitation URL.
157 * The application should call free() after it has finished using the URL.
159 extern char *meshlink_invite(meshlink_handle_t *handle, const char *name);
161 /// Use an invitation to join a mesh.
162 /** This function allows the local node to join an existing mesh using an invitation URL generated by another node.
163 * An invitation can only be used if the local node has never connected to other nodes before.
164 * After a succesfully accepted invitation, the name of the local node may have changed.
166 * @param handle A handle which represents an instance of MeshLink.
167 * @param invitation A string containing the invitation URL.
169 * @return This function returns true if the local node joined the mesh it was invited to, false otherwise.
171 extern bool meshlink_join(meshlink_handle_t *handle, const char *invitation);
173 /// Export the local node's key and addresses.
174 /** This function generates a string that contains the local node's public key and one or more IP addresses.
175 * The application can pass it in some way to another node, which can then import it,
176 * granting the local node access to the other node's mesh.
178 * @param handle A handle which represents an instance of MeshLink.
180 * @return This function returns a string that contains the exported key and addresses.
181 * The application should call free() after it has finished using this string.
183 extern char *meshlink_export(meshlink_handle_t *handle);
185 /// Import another node's key and addresses.
186 /** This function accepts a string containing the exported public key and addresses of another node.
187 * By importing this data, the local node grants the other node access to its mesh.
189 * @param handle A handle which represents an instance of MeshLink.
190 * @param data A string containing the other node's exported key and addresses.
192 * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise.
194 extern bool meshlink_import(meshlink_handle_t *handle, const char *data);
196 /// Blacklist a node from the mesh.
197 /** This function causes the local node to blacklist another node.
198 * The local node will drop any existing connections to that node,
199 * and will not send data to it nor accept any data received from it any more.
201 * @param handle A handle which represents an instance of MeshLink.
202 * @param node A pointer to a meshlink_node_t describing the node to be blacklisted.
204 extern void meshlink_blacklist(meshlink_handle_t *handle, meshlink_node_t *node);