From 287899bd4015afe0faff84545f95227846a01b65 Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Sat, 26 Jul 2014 14:17:11 +0200 Subject: [PATCH] Declare the channel API. Channels are very much like TCP connections. Willingness to accept channels is declared by setting a channel_accept callback. New channels can be created by calling channel_open(), data can be sent using channel_send() and data received is passed via a channel_receive callback. --- src/meshlink++.h | 92 ++++++++++++++++++++++++++++++++++++++++ src/meshlink.h | 108 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 200 insertions(+) diff --git a/src/meshlink++.h b/src/meshlink++.h index a4829a45..dc32855a 100644 --- a/src/meshlink++.h +++ b/src/meshlink++.h @@ -25,6 +25,7 @@ namespace meshlink { class mesh; class node; + class channel; /// Severity of log messages generated by MeshLink. typedef meshlink_log_level_t log_level_t; @@ -54,10 +55,35 @@ namespace meshlink { */ typedef void (*log_cb_t)(mesh *mesh, log_level_t level, const char *text); + /// A callback for accepting incoming channels. + /** @param mesh A handle which represents an instance of MeshLink. + * @param channel A handle for the incoming channel. + * @param node The node from which this channel is being initiated. + * @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.) + * @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 (*channel_accept_cb_t)(mesh *mesh, channel *channel, node *node, uint16_t port, void *data, size_t len); + + /// A callback for receiving data from a 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. + * @param len The length of the data. + */ + typedef void (*channel_receive_cb_t)(mesh *mesh, channel *channel, void *data, size_t len); + /// A class describing a MeshLink node. class node: public meshlink_node_t { }; + /// A class describing a MeshLink channel. + class channel: public meshlink_channel_t { + }; + /// A class describing a MeshLink mesh. class mesh: public meshlink_handle_t { public: @@ -265,6 +291,72 @@ namespace meshlink { void blacklist(node *node) { return meshlink_blacklist(this, node); } + + /// 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. + * + * @param cb A pointer to the function which will be called when another node sends data to the local node. + */ + void set_channel_accept_cb(channel *channel, channel_accept_cb_t cb) { + return meshlink_set_channel_accept_cb(this, (meshlink_channel_accept_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. + * + * @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. + * @param len The length of the data. + * + * @return A handle for the channel, or NULL in case of an error. + */ + channel *channel_open(node *node, uint16_t port, channel_receive_cb_t recv, void *data, size_t len) { + return (channel *)meshlink_channel_open(this, node, port, (meshlink_channel_receive_cb_t)recv, data, 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. + * + * @param channel A handle for the channel. + * @param direction Must be one of SHUT_RD, SHUT_WR or SHUT_RDWR. + */ + void channel_shutdown(channel *channel, int direction) { + return meshlink_channel_shutdown(this, channel, 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. + * Afterwards, the channel handle is invalid and must not be used any more. + * + * @param channel A handle for the channel. + */ + void channel_close(meshlink_channel_t *channel) { + return meshlink_channel_close(this, channel); + } + + /// Transmit data on a channel + /** This queues data to send to the remote node. + * + * @param channel A handle for the channel. + * @param data A pointer to a buffer containing data sent by the source. + * @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. + */ + ssize_t channel_send(channel *channel, void *data, size_t len) { + return meshlink_channel_send(this, channel, data, len); + } + }; /// Initialize MeshLink's configuration directory. diff --git a/src/meshlink.h b/src/meshlink.h index afa6032c..9db3c3d8 100644 --- a/src/meshlink.h +++ b/src/meshlink.h @@ -20,8 +20,10 @@ #ifndef MESHLINK_H #define MESHLINK_H +#include #include #include +#include #ifdef __cplusplus extern "C" { @@ -35,6 +37,9 @@ 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 @@ -54,6 +59,9 @@ struct meshlink_node { void *priv; ///< Private pointer which the application can set at will. }; +struct meshlink_channel { +}; + #endif // MESHLINK_INTERNAL_H /// Get the text for the given MeshLink error code. @@ -312,6 +320,106 @@ extern bool meshlink_import(meshlink_handle_t *mesh, const char *data); */ 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. + * @param node The node from which this channel is being initiated. + * @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.) + * @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, 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. + * @param len The length of the data. + */ +typedef void (*meshlink_channel_receive_cb_t)(meshlink_handle_t *mesh, meshlink_channel_t *channel, 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. + * + * @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. + */ +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. + */ +extern void meshlink_set_channel_receive_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_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. + * + * @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. + * @param len The length of the data. + * + * @return A handle for the channel, or NULL in case of an error. + */ +extern meshlink_channel_t *meshlink_channel_open(meshlink_handle_t *mesh, meshlink_node_t *node, uint16_t port, meshlink_channel_receive_cb_t cb, 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. + * + * @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. + * 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. + * @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, void *data, size_t len); + #ifdef __cplusplus } #endif -- 2.39.5