LNXCORE/v8/include/libwebsockets/lws-protocols-plugins.h
2025-01-22 17:22:38 +01:00

384 lines
14 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
/*! \defgroup Protocols-and-Plugins Protocols and Plugins
* \ingroup lwsapi
*
* ##Protocol and protocol plugin -related apis
*
* Protocols bind ws protocol names to a custom callback specific to that
* protocol implementaion.
*
* A list of protocols can be passed in at context creation time, but it is
* also legal to leave that NULL and add the protocols and their callback code
* using plugins.
*
* Plugins are much preferable compared to cut and pasting code into an
* application each time, since they can be used standalone.
*/
///@{
/** struct lws_protocols - List of protocols and handlers client or server
* supports. */
struct lws_protocols {
const char *name;
/**< Protocol name that must match the one given in the client
* Javascript new WebSocket(url, 'protocol') name. */
lws_callback_function *callback;
/**< The service callback used for this protocol. It allows the
* service action for an entire protocol to be encapsulated in
* the protocol-specific callback */
size_t per_session_data_size;
/**< Each new connection using this protocol gets
* this much memory allocated on connection establishment and
* freed on connection takedown. A pointer to this per-connection
* allocation is passed into the callback in the 'user' parameter */
size_t rx_buffer_size;
/**< lws allocates this much space for rx data and informs callback
* when something came. Due to rx flow control, the callback may not
* be able to consume it all without having to return to the event
* loop. That is supported in lws.
*
* If .tx_packet_size is 0, this also controls how much may be sent at
* once for backwards compatibility.
*/
unsigned int id;
/**< ignored by lws, but useful to contain user information bound
* to the selected protocol. For example if this protocol was
* called "myprotocol-v2", you might set id to 2, and the user
* code that acts differently according to the version can do so by
* switch (wsi->a.protocol->id), user code might use some bits as
* capability flags based on selected protocol version, etc. */
void *user; /**< ignored by lws, but user code can pass a pointer
here it can later access from the protocol callback */
size_t tx_packet_size;
/**< 0 indicates restrict send() size to .rx_buffer_size for backwards-
* compatibility.
* If greater than zero, a single send() is restricted to this amount
* and any remainder is buffered by lws and sent afterwards also in
* these size chunks. Since that is expensive, it's preferable
* to restrict one fragment you are trying to send to match this
* size.
*/
/* Add new things just above here ---^
* This is part of the ABI, don't needlessly break compatibility */
};
#define LWS_PROTOCOL_LIST_TERM { NULL, NULL, 0, 0, 0, NULL, 0 }
/**
* lws_vhost_name_to_protocol() - get vhost's protocol object from its name
*
* \param vh: vhost to search
* \param name: protocol name
*
* Returns NULL or a pointer to the vhost's protocol of the requested name
*/
LWS_VISIBLE LWS_EXTERN const struct lws_protocols *
lws_vhost_name_to_protocol(struct lws_vhost *vh, const char *name);
/**
* lws_get_protocol() - Returns a protocol pointer from a websocket
* connection.
* \param wsi: pointer to struct websocket you want to know the protocol of
*
*
* Some apis can act on all live connections of a given protocol,
* this is how you can get a pointer to the active protocol if needed.
*/
LWS_VISIBLE LWS_EXTERN const struct lws_protocols *
lws_get_protocol(struct lws *wsi);
/** lws_protocol_get() - deprecated: use lws_get_protocol */
LWS_VISIBLE LWS_EXTERN const struct lws_protocols *
lws_protocol_get(struct lws *wsi) LWS_WARN_DEPRECATED;
/**
* lws_protocol_vh_priv_zalloc() - Allocate and zero down a protocol's per-vhost
* storage
* \param vhost: vhost the instance is related to
* \param prot: protocol the instance is related to
* \param size: bytes to allocate
*
* Protocols often find it useful to allocate a per-vhost struct, this is a
* helper to be called in the per-vhost init LWS_CALLBACK_PROTOCOL_INIT
*/
LWS_VISIBLE LWS_EXTERN void *
lws_protocol_vh_priv_zalloc(struct lws_vhost *vhost,
const struct lws_protocols *prot, int size);
/**
* lws_protocol_vh_priv_get() - retreive a protocol's per-vhost storage
*
* \param vhost: vhost the instance is related to
* \param prot: protocol the instance is related to
*
* Recover a pointer to the allocated per-vhost storage for the protocol created
* by lws_protocol_vh_priv_zalloc() earlier
*/
LWS_VISIBLE LWS_EXTERN void *
lws_protocol_vh_priv_get(struct lws_vhost *vhost,
const struct lws_protocols *prot);
/**
* lws_vhd_find_by_pvo() - find a partner vhd
*
* \param cx: the lws_context
* \param protname: the name of the lws_protocol the vhd belongs to
* \param pvo_name: the name of a pvo that must exist bound to the vhd
* \param pvo_value: the required value of the named pvo
*
* This allows architectures with multiple protocols bound together to
* cleanly discover partner protocol instances even on completely
* different vhosts. For example, a proxy may consist of two protocols
* listening on different vhosts, and there may be multiple instances
* of the proxy in the same process. It's desirable that each side of
* the proxy is an independent protocol that can be freely bound to any
* vhost, eg, allowing Unix Domain to tls / h2 proxying, or each side
* bound to different network interfaces for localhost-only visibility
* on one side, using existing vhost management.
*
* That leaves the problem that the two sides have to find each other
* and bind at runtime. This api allows each side to specify the
* protocol name, and a common pvo name and pvo value that indicates
* the two sides belong together, and search through all the instantiated
* vhost-protocols looking for a match. If found, the private allocation
* (aka "vhd" of the match is returned). NULL is returned on no match.
*
* Since this can only succeed when called by the last of the two
* protocols to be instantiated, both sides should call it and handle
* NULL gracefully, since it may mean that they were first and their
* partner vhsot-protocol has not been instantiated yet.
*/
LWS_VISIBLE LWS_EXTERN void *
lws_vhd_find_by_pvo(struct lws_context *cx, const char *protname,
const char *pvo_name, const char *pvo_value);
/**
* lws_adjust_protocol_psds - change a vhost protocol's per session data size
*
* \param wsi: a connection with the protocol to change
* \param new_size: the new size of the per session data size for the protocol
*
* Returns user_space for the wsi, after allocating
*
* This should not be used except to initalize a vhost protocol's per session
* data size one time, before any connections are accepted.
*
* Sometimes the protocol wraps another protocol and needs to discover and set
* its per session data size at runtime.
*/
LWS_VISIBLE LWS_EXTERN void *
lws_adjust_protocol_psds(struct lws *wsi, size_t new_size);
/**
* lws_finalize_startup() - drop initial process privileges
*
* \param context: lws context
*
* This is called after the end of the vhost protocol initializations, but
* you may choose to call it earlier
*/
LWS_VISIBLE LWS_EXTERN int
lws_finalize_startup(struct lws_context *context);
/**
* lws_pvo_search() - helper to find a named pvo in a linked-list
*
* \param pvo: the first pvo in the linked-list
* \param name: the name of the pvo to return if found
*
* Returns NULL, or a pointer to the name pvo in the linked-list
*/
LWS_VISIBLE LWS_EXTERN const struct lws_protocol_vhost_options *
lws_pvo_search(const struct lws_protocol_vhost_options *pvo, const char *name);
/**
* lws_pvo_get_str() - retreive a string pvo value
*
* \param in: the first pvo in the linked-list
* \param name: the name of the pvo to return if found
* \param result: pointer to a const char * to get the result if any
*
* Returns 0 if found and *result set, or nonzero if not found
*/
LWS_VISIBLE LWS_EXTERN int
lws_pvo_get_str(void *in, const char *name, const char **result);
LWS_VISIBLE LWS_EXTERN int
lws_protocol_init(struct lws_context *context);
#define LWS_PLUGIN_API_MAGIC 191
/*
* Abstract plugin header for any kind of plugin class, always at top of
* actual class plugin export type.
*
* The export type object must be exported with the same name as the plugin
* file, eg, libmyplugin.so must export a const one of these as the symbol
* "myplugin".
*
* That is the only expected export from the plugin.
*/
typedef struct lws_plugin_header {
const char *name;
const char *_class;
const char *lws_build_hash; /* set to LWS_BUILD_HASH */
unsigned int api_magic;
/* set to LWS_PLUGIN_API_MAGIC at plugin build time */
/* plugin-class specific superclass data follows */
} lws_plugin_header_t;
/*
* "lws_protocol_plugin" class export, for lws_protocol implementations done
* as plugins
*/
typedef struct lws_plugin_protocol {
lws_plugin_header_t hdr;
const struct lws_protocols *protocols; /**< array of supported protocols provided by plugin */
const struct lws_extension *extensions; /**< array of extensions provided by plugin */
int count_protocols; /**< how many protocols */
int count_extensions; /**< how many extensions */
} lws_plugin_protocol_t;
/*
* This is the dynamic, runtime created part of the plugin instantiation.
* These are kept in a linked-list and destroyed with the context.
*/
struct lws_plugin {
struct lws_plugin *list; /**< linked list */
const lws_plugin_header_t *hdr;
union {
#if defined(LWS_WITH_LIBUV) && defined(UV_ERRNO_MAP)
#if (UV_VERSION_MAJOR > 0)
uv_lib_t lib; /**< shared library pointer */
#endif
#endif
void *l; /**< */
} u;
};
/*
* Event lib library plugin type (when LWS_WITH_EVLIB_PLUGINS)
* Public so new event libs can equally be supported outside lws itself
*/
typedef struct lws_plugin_evlib {
lws_plugin_header_t hdr;
const struct lws_event_loop_ops *ops;
} lws_plugin_evlib_t;
typedef int (*each_plugin_cb_t)(struct lws_plugin *p, void *user);
/**
* lws_plugins_init() - dynamically load plugins of matching class from dirs
*
* \param pplugin: pointer to linked-list for this kind of plugin
* \param d: array of directory paths to look in
* \param _class: class string that plugin must declare
* \param filter: NULL, or a string that must appear after the third char of the plugin filename
* \param each: NULL, or each_plugin_cb_t callback for each instantiated plugin
* \param each_user: pointer passed to each callback
*
* Allows you to instantiate a class of plugins to a specified linked-list.
* The each callback allows you to init each inistantiated callback and pass a
* pointer each_user to it.
*
* To take down the plugins, pass a pointer to the linked-list head to
* lws_plugins_destroy.
*
* This is used for lws protocol plugins but you can define your own plugin
* class name like "mypluginclass", declare it in your plugin headers, and load
* your own plugins to your own list using this api the same way.
*/
LWS_VISIBLE LWS_EXTERN int
lws_plugins_init(struct lws_plugin **pplugin, const char * const *d,
const char *_class, const char *filter,
each_plugin_cb_t each, void *each_user);
/**
* lws_plugins_destroy() - dynamically unload list of plugins
*
* \param pplugin: pointer to linked-list for this kind of plugin
* \param each: NULL, or each_plugin_cb_t callback for each instantiated plugin
* \param each_user: pointer passed to each callback
*
* Allows you to destroy a class of plugins from a specified linked-list
* created by a call to lws_plugins_init().
*
* The each callback allows you to deinit each inistantiated callback and pass a
* pointer each_user to it, just before its footprint is destroyed.
*/
LWS_VISIBLE LWS_EXTERN int
lws_plugins_destroy(struct lws_plugin **pplugin, each_plugin_cb_t each,
void *each_user);
#if defined(LWS_WITH_PLUGINS_BUILTIN)
/* provide exports for builtin plugin protocols */
extern const struct lws_protocols post_demo_protocols[1];
extern const struct lws_protocols lws_raw_proxy_protocols[1];
extern const struct lws_protocols lws_status_protocols[1];
extern const struct lws_protocols lws_mirror_protocols[1];
extern const struct lws_protocols lws_ssh_base_protocols[2];
extern const struct lws_protocols post_demo_protocols[1];
extern const struct lws_protocols dumb_increment_protocols[1];
extern const struct lws_protocols deaddrop_protocols[1];
extern const struct lws_protocols lws_raw_test_protocols[1];
extern const struct lws_protocols lws_sshd_demo_protocols[1];
extern const struct lws_protocols lws_acme_client_protocols[1];
extern const struct lws_protocols client_loopback_test_protocols[1];
extern const struct lws_protocols fulltext_demo_protocols[1];
extern const struct lws_protocols lws_openmetrics_export_protocols[
#if defined(LWS_WITH_SERVER) && defined(LWS_WITH_CLIENT) && defined(LWS_ROLE_WS)
4
#else
#if defined(LWS_WITH_SERVER)
3
#else
1
#endif
#endif
];
#define LWSOMPROIDX_DIRECT_HTTP_SERVER 0
#define LWSOMPROIDX_PROX_HTTP_SERVER 1
#define LWSOMPROIDX_PROX_WS_SERVER 2
#define LWSOMPROIDX_PROX_WS_CLIENT 3
#endif
///@}