X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fmeshlink.h;h=a21af570d54c75c81a2b61425acce7524a424af6;hb=a568bee4fa65742b452a8bd003c86d58d942e45f;hp=fdf0896e3e51786612ff47b5f61529786bc8c981;hpb=f7966aeb18195987a244e37df49847af5766605d;p=meshlink diff --git a/src/meshlink.h b/src/meshlink.h index fdf0896e..a21af570 100644 --- a/src/meshlink.h +++ b/src/meshlink.h @@ -20,36 +20,48 @@ #ifndef MESHLINK_H #define MESHLINK_H +#include #include #include +#include #ifdef __cplusplus extern "C" { #endif +/// The length in bytes of a signature made with meshlink_sign() +#define MESHLINK_SIGLEN 64 + /// A handle for an instance of MeshLink. typedef struct meshlink_handle meshlink_handle_t; /// A handle for a MeshLink node. typedef struct meshlink_node meshlink_node_t; +/// A handle for a MeshLink channel. +typedef struct meshlink_channel meshlink_channel_t; + /// Code of most recent error encountered. typedef enum { - MESHLINK_OK, // Everything is fine - MESHLINK_ENOMEM, // Out of memory - MESHLINK_ENOENT, // Node is not known + MESHLINK_OK, ///< Everything is fine + MESHLINK_ENOMEM, ///< Out of memory + MESHLINK_ENOENT, ///< Node is not known } meshlink_errno_t; +/// A variable holding the last encountered error from MeshLink. +extern __thread meshlink_errno_t meshlink_errno; + #ifndef MESHLINK_INTERNAL_H struct meshlink_handle { - meshlink_errno_t meshlink_errno; /// Code of the last encountered error. - const char *errstr; /// Textual representation of most recent error encountered. }; struct meshlink_node { - const char *name; // Textual name of this node. - void *priv; // Private pointer which the application can set at will. + const char *name; ///< Textual name of this node. + void *priv; ///< Private pointer which the application can set at will. +}; + +struct meshlink_channel { }; #endif // MESHLINK_INTERNAL_H @@ -63,20 +75,29 @@ struct meshlink_node { */ extern const char *meshlink_strerror(meshlink_errno_t errno); -/// Initialize MeshLink's configuration directory. -/** This function causes MeshLink to initialize its configuration directory, - * if it hasn't already been initialized. - * It only has to be run the first time the application starts, - * but it is not a problem if it is run more than once, as long as - * the arguments given are the same. +/// Open or create a MeshLink instance. +/** This function opens or creates a MeshLink instance. + * The state is stored in the configuration directory passed in the variable @a confbase @a. + * If the configuration directory does not exist yet, for example when it is the first time + * this instance is opened, the configuration directory will be automatically created and initialized. + * However, the parent directory should already exist, otherwise an error will be returned. + * + * The name given should be a unique identifier for this instance. + * + * This function returns a pointer to a struct meshlink_handle that will be allocated by MeshLink. + * When the application does no longer need to use this handle, it must call meshlink_close() to + * free its resources. * * This function does not start any network I/O yet. The application should * first set callbacks, and then call meshlink_start(). * * @param confbase The directory in which MeshLink will store its configuration files. + * After the function returns, the application is free to overwrite or free @a confbase @a. * @param name The name which this instance of the application will use in the mesh. + * After the function returns, the application is free to overwrite or free @a name @a. * - * @return This function will return true if MeshLink has succesfully set up its configuration files, false otherwise. + * @return A pointer to a meshlink_handle_t which represents this instance of MeshLink. + * The pointer is valid until meshlink_close() is called. */ extern meshlink_handle_t *meshlink_open(const char *confbase, const char *name); @@ -84,7 +105,7 @@ extern meshlink_handle_t *meshlink_open(const char *confbase, const char *name); /** This function causes MeshLink to open network sockets, make outgoing connections, and * create a new thread, which will handle all network I/O. * - * @param confbase The directory in which MeshLink will store its configuration files. + * @param mesh A handle which represents an instance of MeshLink. * * @return This function will return true if MeshLink has succesfully started its thread, false otherwise. */ @@ -94,23 +115,25 @@ extern bool meshlink_start(meshlink_handle_t *mesh); /** This function causes MeshLink to disconnect from all other nodes, * close all sockets, and shut down its own thread. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. */ extern void meshlink_stop(meshlink_handle_t *mesh); /// Close the MeshLink handle. /** This function calls meshlink_stop() if necessary, - * and frees all memory allocated by MeshLink. - * Afterwards, the handle and any pointers to a struct meshlink_node are invalid. + * and frees the struct meshlink_handle and all associacted memory allocated by MeshLink. + * Afterwards, the handle and any pointers to a struct meshlink_node or struct meshlink_channel are invalid. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. */ extern void meshlink_close(meshlink_handle_t *mesh); /// A callback for receiving data from the mesh. -/** @param handle A handle which represents an instance of MeshLink. +/** @param mesh A handle which represents an instance of MeshLink. * @param source A pointer to a meshlink_node_t describing the source of the data. * @param data A pointer to a buffer containing the data sent by the source. + * The pointer is only valid during the lifetime of the callback. + * The callback should mempcy() the data if it needs to be available outside the callback. * @param len The length of the received data. */ typedef void (*meshlink_receive_cb_t)(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len); @@ -122,13 +145,14 @@ typedef void (*meshlink_receive_cb_t)(meshlink_handle_t *mesh, meshlink_node_t * * to hand the data over to the application's thread. * The callback should also not block itself and return as quickly as possible. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param cb A pointer to the function which will be called when another node sends data to the local node. + * If a NULL pointer is given, the callback will be disabled. */ extern void meshlink_set_receive_cb(meshlink_handle_t *mesh, meshlink_receive_cb_t cb); /// A callback reporting node status changes. -/** @param handle A handle which represents an instance of MeshLink. +/** @param mesh A handle which represents an instance of MeshLink. * @param node A pointer to a meshlink_node_t describing the node whose status changed. * @param reachable True if the node is reachable, false otherwise. */ @@ -141,24 +165,27 @@ typedef void (*meshlink_node_status_cb_t)(meshlink_handle_t *mesh, meshlink_node * to hand the data over to the application's thread. * The callback should also not block itself and return as quickly as possible. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param cb A pointer to the function which will be called when another node's status changes. + * If a NULL pointer is given, the callback will be disabled. */ extern void meshlink_set_node_status_cb(meshlink_handle_t *mesh, meshlink_node_status_cb_t cb); /// Severity of log messages generated by MeshLink. typedef enum { - MESHLINK_DEBUG, // Internal debugging messages. Only useful during application development. - MESHLINK_INFO, // Informational messages. - MESHLINK_WARNING, // Warnings which might indicate problems, but which are not real errors. - MESHLINK_ERROR, // Errors which hamper correct functioning of MeshLink, without causing it to fail completely. - MESHLINK_CRITICAL, // Critical errors which cause MeshLink to fail completely. + MESHLINK_DEBUG, ///< Internal debugging messages. Only useful during application development. + MESHLINK_INFO, ///< Informational messages. + MESHLINK_WARNING, ///< Warnings which might indicate problems, but which are not real errors. + MESHLINK_ERROR, ///< Errors which hamper correct functioning of MeshLink, without causing it to fail completely. + MESHLINK_CRITICAL, ///< Critical errors which cause MeshLink to fail completely. } meshlink_log_level_t; /// A callback for receiving log messages generated by MeshLink. -/** @param handle A handle which represents an instance of MeshLink. +/** @param mesh A handle which represents an instance of MeshLink. * @param level An enum describing the severity level of the message. * @param text A pointer to a string containing the textual log message. + * This pointer is only valid for the duration of the callback. + * The application should strdup() the text if it has to be available outside the callback. */ typedef void (*meshlink_log_cb_t)(meshlink_handle_t *mesh, meshlink_log_level_t level, const char *text); @@ -169,9 +196,10 @@ typedef void (*meshlink_log_cb_t)(meshlink_handle_t *mesh, meshlink_log_level_t * to hand the data over to the application's thread. * The callback should also not block itself and return as quickly as possible. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param level An enum describing the minimum severity level. Debugging information with a lower level will not trigger the callback. * @param cb A pointer to the function which will be called when another node sends data to the local node. + * If a NULL pointer is given, the callback will be disabled. */ extern void meshlink_set_log_cb(meshlink_handle_t *mesh, meshlink_log_level_t level, meshlink_log_cb_t cb); @@ -182,9 +210,10 @@ extern void meshlink_set_log_cb(meshlink_handle_t *mesh, meshlink_log_level_t le * and that there is no guarantee that the packet will arrive at the destination. * The application should take care of getting an acknowledgement and retransmission if necessary. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param destination A pointer to a meshlink_node_t describing the destination for the data. * @param data A pointer to a buffer containing the data to be sent to the source. + * After meshlink_send() returns, the application is free to overwrite or free this buffer. * @param len The length of the data. * @return This function will return true if MeshLink has queued the message for transmission, and false otherwise. * A return value of true does not guarantee that the message will actually arrive at the destination. @@ -194,50 +223,68 @@ extern bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, /// Get a handle for a specific node. /** This function returns a handle for the node with the given name. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param name The name of the node for which a handle is requested. + * After this function returns, the application is free to overwrite or free @a name @a. * * @return A pointer to a meshlink_node_t which represents the requested node, * or NULL if the requested node does not exist. + * The pointer is guaranteed to be valid until meshlink_close() is called. */ extern meshlink_node_t *meshlink_get_node(meshlink_handle_t *mesh, const char *name); /// Get a list of all nodes. /** This function returns a list with handles for all known nodes. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param nodes A pointer to an array of pointers to meshlink_node_t, which should be allocated by the application. + * The pointers are valid until meshlink_close() is called. * @param nmemb The maximum number of pointers that can be stored in the nodes array. * - * @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. + * @return The number of known nodes, or -1 in case of an error. + * The returned number of nodes can be larger than nmemb, in which case not all nodes were stored in the nodes array. */ -extern size_t meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_t **nodes, size_t nmemb); +extern ssize_t meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_t **nodes, size_t nmemb); /// Sign data using the local node's MeshLink key. /** This function signs data using the local node's MeshLink key. * The generated signature can be securely verified by other nodes. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param data A pointer to a buffer containing the data to be signed. * @param len The length of the data to be signed. + * @param signature A pointer to a buffer where the signature will be stored. + * The buffer must be allocated by the application, and should be at least MESHLINK_SIGLEN bytes big. + * @param siglen The size of the signature buffer. Will be changed after the call to match the size of the signature itself. * - * @return This function returns a pointer to a string containing the signature, or NULL in case of an error. - * The application should call free() after it has finished using the signature. + * @return This function returns true if the signature was correctly generated, false otherwise. */ -extern char *meshlink_sign(meshlink_handle_t *mesh, const char *data, size_t len); +extern bool meshlink_sign(meshlink_handle_t *mesh, const void *data, size_t len, void *signature, size_t *siglen); /// Verify the signature generated by another node of a piece of data. /** This function verifies the signature that another node generated for a piece of data. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param source A pointer to a meshlink_node_t describing the source of the signature. * @param data A pointer to a buffer containing the data to be verified. * @param len The length of the data to be verified. - * @param signature A pointer to a string containing the signature. + * @param signature A pointer to a buffer where the signature will be stored. + * @param siglen A pointer to a variable holding the size of the signature buffer. + * The contents of the variable will be changed by meshlink_sign() to reflect the actual size of the signature. * * @return This function returns true if the signature is valid, false otherwise. */ -extern bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const char *data, size_t len, const char *signature); +extern bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len, const void *signature, size_t siglen); + +/// Add an Address for the local node. +/** This function adds an Address for the local node, which will be used for invitation URLs. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param address A string containing the address, which can be either in numeric format or a hostname. + * + * @return This function returns true if the address was added, false otherwise. + */ +extern bool meshlink_add_address(meshlink_handle_t *mesh, const char *address); /// Invite another node into the mesh. /** This function generates an invitation that can be used by another node to join the same mesh as the local node. @@ -245,8 +292,9 @@ extern bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, co * This URL should be passed by the application to the invitee in a way that no eavesdroppers can see the URL. * The URL can only be used once, after the user has joined the mesh the URL is no longer valid. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param name The name that the invitee will use in the mesh. + * After this function returns, the application is free to overwrite or free @a name @a. * * @return This function returns a string that contains the invitation URL. * The application should call free() after it has finished using the URL. @@ -258,8 +306,9 @@ extern char *meshlink_invite(meshlink_handle_t *mesh, const char *name); * An invitation can only be used if the local node has never connected to other nodes before. * After a succesfully accepted invitation, the name of the local node may have changed. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param invitation A string containing the invitation URL. + * After this function returns, the application is free to overwrite or free @a invitation @a. * * @return This function returns true if the local node joined the mesh it was invited to, false otherwise. */ @@ -270,7 +319,7 @@ extern bool meshlink_join(meshlink_handle_t *mesh, const char *invitation); * The application can pass it in some way to another node, which can then import it, * granting the local node access to the other node's mesh. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * * @return This function returns a string that contains the exported key and addresses. * The application should call free() after it has finished using this string. @@ -281,8 +330,9 @@ extern char *meshlink_export(meshlink_handle_t *mesh); /** This function accepts a string containing the exported public key and addresses of another node. * By importing this data, the local node grants the other node access to its mesh. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param data A string containing the other node's exported key and addresses. + * After this function returns, the application is free to overwrite or free @a data @a. * * @return This function returns true if the data was valid and the other node has been granted access to the mesh, false otherwise. */ @@ -293,11 +343,135 @@ extern bool meshlink_import(meshlink_handle_t *mesh, const char *data); * The local node will drop any existing connections to that node, * and will not send data to it nor accept any data received from it any more. * - * @param handle A handle which represents an instance of MeshLink. + * @param mesh A handle which represents an instance of MeshLink. * @param node A pointer to a meshlink_node_t describing the node to be blacklisted. */ extern void meshlink_blacklist(meshlink_handle_t *mesh, meshlink_node_t *node); +/// A callback for accepting incoming channels. +/** This function is called whenever a remote node wants to open a channel to the local node. + * The application then has to decide whether to accept or reject this channel. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the incoming channel. + * If the application accepts the incoming channel by returning true, + * then this handle is valid until meshlink_channel_close() is called on it. + * If the application rejects the incoming channel by returning false, + * then this handle is invalid after the callback returns + * (the callback does not need to call meshlink_channel_close() itself in this case). + * @param node The node from which this channel is being initiated. + * The pointer is guaranteed to be valid until meshlink_close() is called. + * @param port The port number the peer wishes to connect to. + * @param data A pointer to a buffer containing data already received. (Not yet used.) + * The pointer is only valid during the lifetime of the callback. + * The callback should mempcy() the data if it needs to be available outside the callback. + * @param len The length of the data. (Not yet used.) + * + * @return This function should return true if the application accepts the incoming channel, false otherwise. + * If returning false, the channel is invalid and may not be used anymore. + */ +typedef bool (*meshlink_channel_accept_cb_t)(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_node_t *node, uint16_t port, const void *data, size_t len); + +/// A callback for receiving data from a channel. +/** This function is called whenever a remote node wants to open a channel to the local node. + * The application then has to decide whether to accept or reject this channel. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the channel. + * @param data A pointer to a buffer containing data sent by the source. + * The pointer is only valid during the lifetime of the callback. + * The callback should mempcy() the data if it needs to be available outside the callback. + * @param len The length of the data. + */ +typedef void (*meshlink_channel_receive_cb_t)(meshlink_handle_t *mesh, meshlink_channel_t *channel, const void *data, size_t len); + +/// Set the accept callback. +/** This functions sets the callback that is called whenever another node sends data to the local node. + * The callback is run in MeshLink's own thread. + * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.) + * to hand the data over to the application's thread. + * The callback should also not block itself and return as quickly as possible. + * + * If no accept callback is set, incoming channels are rejected. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param cb A pointer to the function which will be called when another node sends data to the local node. + * If a NULL pointer is given, the callback will be disabled. + */ +extern void meshlink_set_channel_accept_cb(meshlink_handle_t *mesh, meshlink_channel_accept_cb_t cb); + +/// Set the receive callback. +/** This functions sets the callback that is called whenever another node sends data to the local node. + * The callback is run in MeshLink's own thread. + * It is therefore important that the callback uses apprioriate methods (queues, pipes, locking, etc.) + * to hand the data over to the application's thread. + * The callback should also not block itself and return as quickly as possible. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the channel. + * @param cb A pointer to the function which will be called when another node sends data to the local node. + * If a NULL pointer is given, the callback will be disabled. + */ +extern void meshlink_set_channel_receive_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_channel_receive_cb_t cb); + +/// Open a reliable stream channel to another node. +/** This function is called whenever a remote node wants to open a channel to the local node. + * The application then has to decide whether to accept or reject this channel. + * + * This function returns a pointer to a struct meshlink_channel that will be allocated by MeshLink. + * When the application does no longer need to use this channel, it must call meshlink_close() + * to free its resources. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param node The node to which this channel is being initiated. + * @param port The port number the peer wishes to connect to. + * @param cb A pointer to the function which will be called when the remote node sends data to the local node. + * @param data A pointer to a buffer containing data to already queue for sending. + * After meshlink_send() returns, the application is free to overwrite or free this buffer. + * @param len The length of the data. + * + * @return A handle for the channel, or NULL in case of an error. + * The handle is valid until meshlink_channel_close() is called. + */ +extern meshlink_channel_t *meshlink_channel_open(meshlink_handle_t *mesh, meshlink_node_t *node, uint16_t port, meshlink_channel_receive_cb_t cb, const void *data, size_t len); + +/// Partially close a reliable stream channel. +/** This shuts down the read or write side of a channel, or both, without closing the handle. + * It can be used to inform the remote node that the local node has finished sending all data on the channel, + * but still allows waiting for incoming data from the remote node. + * + * Shutting down the receive direction is also possible, and is equivalent to setting the receive callback to NULL. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the channel. + * @param direction Must be one of SHUT_RD, SHUT_WR or SHUT_RDWR. + */ +extern void meshlink_channel_shutdown(meshlink_handle_t *mesh, meshlink_channel_t *channel, int direction); + +/// Close a reliable stream channel. +/** This informs the remote node that the local node has finished sending all data on the channel. + * It also causes the local node to stop accepting incoming data from the remote node. + * It will free the struct meshlink_channel and all associated resources. + * Afterwards, the channel handle is invalid and must not be used any more. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the channel. + */ +extern void meshlink_channel_close(meshlink_handle_t *mesh, meshlink_channel_t *channel); + +/// Transmit data on a channel +/** This queues data to send to the remote node. + * + * @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the channel. + * @param data A pointer to a buffer containing data sent by the source. + * After meshlink_send() returns, the application is free to overwrite or free this buffer. + * @param len The length of the data. + * + * @return The amount of data that was queued, which can be less than len, or a negative value in case of an error. + */ +extern ssize_t meshlink_channel_send(meshlink_handle_t *mesh, meshlink_channel_t *channel, const void *data, size_t len); + #ifdef __cplusplus } #endif