479 lines
16 KiB
C
479 lines
16 KiB
C
/* $NetBSD: evrpc.h,v 1.1 2008/05/16 20:24:58 peter Exp $ */
|
|
/*
|
|
* Copyright (c) 2006 Niels Provos <provos@citi.umich.edu>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
#ifndef _EVRPC_H_
|
|
#define _EVRPC_H_
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
/** @file evrpc.h
|
|
*
|
|
* This header files provides basic support for an RPC server and client.
|
|
*
|
|
* To support RPCs in a server, every supported RPC command needs to be
|
|
* defined and registered.
|
|
*
|
|
* EVRPC_HEADER(SendCommand, Request, Reply);
|
|
*
|
|
* SendCommand is the name of the RPC command.
|
|
* Request is the name of a structure generated by event_rpcgen.py.
|
|
* It contains all parameters relating to the SendCommand RPC. The
|
|
* server needs to fill in the Reply structure.
|
|
* Reply is the name of a structure generated by event_rpcgen.py. It
|
|
* contains the answer to the RPC.
|
|
*
|
|
* To register an RPC with an HTTP server, you need to first create an RPC
|
|
* base with:
|
|
*
|
|
* struct evrpc_base *base = evrpc_init(http);
|
|
*
|
|
* A specific RPC can then be registered with
|
|
*
|
|
* EVRPC_REGISTER(base, SendCommand, Request, Reply, FunctionCB, arg);
|
|
*
|
|
* when the server receives an appropriately formatted RPC, the user callback
|
|
* is invokved. The callback needs to fill in the reply structure.
|
|
*
|
|
* void FunctionCB(EVRPC_STRUCT(SendCommand)* rpc, void *arg);
|
|
*
|
|
* To send the reply, call EVRPC_REQUEST_DONE(rpc);
|
|
*
|
|
* See the regression test for an example.
|
|
*/
|
|
|
|
struct evbuffer;
|
|
struct event_base;
|
|
struct evrpc_req_generic;
|
|
|
|
/* Encapsulates a request */
|
|
struct evrpc {
|
|
TAILQ_ENTRY(evrpc) next;
|
|
|
|
/* the URI at which the request handler lives */
|
|
const char* uri;
|
|
|
|
/* creates a new request structure */
|
|
void *(*request_new)(void);
|
|
|
|
/* frees the request structure */
|
|
void (*request_free)(void *);
|
|
|
|
/* unmarshals the buffer into the proper request structure */
|
|
int (*request_unmarshal)(void *, struct evbuffer *);
|
|
|
|
/* creates a new reply structure */
|
|
void *(*reply_new)(void);
|
|
|
|
/* creates a new reply structure */
|
|
void (*reply_free)(void *);
|
|
|
|
/* verifies that the reply is valid */
|
|
int (*reply_complete)(void *);
|
|
|
|
/* marshals the reply into a buffer */
|
|
void (*reply_marshal)(struct evbuffer*, void *);
|
|
|
|
/* the callback invoked for each received rpc */
|
|
void (*cb)(struct evrpc_req_generic *, void *);
|
|
void *cb_arg;
|
|
|
|
/* reference for further configuration */
|
|
struct evrpc_base *base;
|
|
};
|
|
|
|
/** The type of a specific RPC Message
|
|
*
|
|
* @param rpcname the name of the RPC message
|
|
*/
|
|
#define EVRPC_STRUCT(rpcname) struct evrpc_req__##rpcname
|
|
|
|
struct evhttp_request;
|
|
struct evrpc_status;
|
|
|
|
/* We alias the RPC specific structs to this voided one */
|
|
struct evrpc_req_generic {
|
|
/* the unmarshaled request object */
|
|
void *request;
|
|
|
|
/* the empty reply object that needs to be filled in */
|
|
void *reply;
|
|
|
|
/*
|
|
* the static structure for this rpc; that can be used to
|
|
* automatically unmarshal and marshal the http buffers.
|
|
*/
|
|
struct evrpc *rpc;
|
|
|
|
/*
|
|
* the http request structure on which we need to answer.
|
|
*/
|
|
struct evhttp_request* http_req;
|
|
|
|
/*
|
|
* callback to reply and finish answering this rpc
|
|
*/
|
|
void (*done)(struct evrpc_req_generic* rpc);
|
|
};
|
|
|
|
/** Creates the definitions and prototypes for an RPC
|
|
*
|
|
* You need to use EVRPC_HEADER to create structures and function prototypes
|
|
* needed by the server and client implementation. The structures have to be
|
|
* defined in an .rpc file and converted to source code via event_rpcgen.py
|
|
*
|
|
* @param rpcname the name of the RPC
|
|
* @param reqstruct the name of the RPC request structure
|
|
* @param replystruct the name of the RPC reply structure
|
|
* @see EVRPC_GENERATE()
|
|
*/
|
|
#define EVRPC_HEADER(rpcname, reqstruct, rplystruct) \
|
|
EVRPC_STRUCT(rpcname) { \
|
|
struct reqstruct* request; \
|
|
struct rplystruct* reply; \
|
|
struct evrpc* rpc; \
|
|
struct evhttp_request* http_req; \
|
|
void (*done)(struct evrpc_status *, \
|
|
struct evrpc* rpc, void *request, void *reply); \
|
|
}; \
|
|
int evrpc_send_request_##rpcname(struct evrpc_pool *, \
|
|
struct reqstruct *, struct rplystruct *, \
|
|
void (*)(struct evrpc_status *, \
|
|
struct reqstruct *, struct rplystruct *, void *cbarg), \
|
|
void *);
|
|
|
|
/** Generates the code for receiving and sending an RPC message
|
|
*
|
|
* EVRPC_GENERATE is used to create the code corresponding to sending
|
|
* and receiving a particular RPC message
|
|
*
|
|
* @param rpcname the name of the RPC
|
|
* @param reqstruct the name of the RPC request structure
|
|
* @param replystruct the name of the RPC reply structure
|
|
* @see EVRPC_HEADER()
|
|
*/
|
|
#define EVRPC_GENERATE(rpcname, reqstruct, rplystruct) \
|
|
int evrpc_send_request_##rpcname(struct evrpc_pool *pool, \
|
|
struct reqstruct *request, struct rplystruct *reply, \
|
|
void (*cb)(struct evrpc_status *, \
|
|
struct reqstruct *, struct rplystruct *, void *cbarg), \
|
|
void *cbarg) { \
|
|
struct evrpc_status status; \
|
|
struct evrpc_request_wrapper *ctx; \
|
|
ctx = (struct evrpc_request_wrapper *) \
|
|
malloc(sizeof(struct evrpc_request_wrapper)); \
|
|
if (ctx == NULL) \
|
|
goto error; \
|
|
ctx->pool = pool; \
|
|
ctx->evcon = NULL; \
|
|
ctx->name = strdup(#rpcname); \
|
|
if (ctx->name == NULL) { \
|
|
free(ctx); \
|
|
goto error; \
|
|
} \
|
|
ctx->cb = (void (*)(struct evrpc_status *, \
|
|
void *, void *, void *))cb; \
|
|
ctx->cb_arg = cbarg; \
|
|
ctx->request = (void *)request; \
|
|
ctx->reply = (void *)reply; \
|
|
ctx->request_marshal = (void (*)(struct evbuffer *, void *))reqstruct##_marshal; \
|
|
ctx->reply_clear = (void (*)(void *))rplystruct##_clear; \
|
|
ctx->reply_unmarshal = (int (*)(void *, struct evbuffer *))rplystruct##_unmarshal; \
|
|
return (evrpc_make_request(ctx)); \
|
|
error: \
|
|
memset(&status, 0, sizeof(status)); \
|
|
status.error = EVRPC_STATUS_ERR_UNSTARTED; \
|
|
(*(cb))(&status, request, reply, cbarg); \
|
|
return (-1); \
|
|
}
|
|
|
|
/** Provides access to the HTTP request object underlying an RPC
|
|
*
|
|
* Access to the underlying http object; can be used to look at headers or
|
|
* for getting the remote ip address
|
|
*
|
|
* @param rpc_req the rpc request structure provided to the server callback
|
|
* @return an struct evhttp_request object that can be inspected for
|
|
* HTTP headers or sender information.
|
|
*/
|
|
#define EVRPC_REQUEST_HTTP(rpc_req) (rpc_req)->http_req
|
|
|
|
/** Creates the reply to an RPC request
|
|
*
|
|
* EVRPC_REQUEST_DONE is used to answer a request; the reply is expected
|
|
* to have been filled in. The request and reply pointers become invalid
|
|
* after this call has finished.
|
|
*
|
|
* @param rpc_req the rpc request structure provided to the server callback
|
|
*/
|
|
#define EVRPC_REQUEST_DONE(rpc_req) do { \
|
|
struct evrpc_req_generic *_req = (struct evrpc_req_generic *)(rpc_req); \
|
|
_req->done(_req); \
|
|
} while (0)
|
|
|
|
|
|
/* Takes a request object and fills it in with the right magic */
|
|
#define EVRPC_REGISTER_OBJECT(rpc, name, request, reply) \
|
|
do { \
|
|
(rpc)->uri = strdup(#name); \
|
|
if ((rpc)->uri == NULL) { \
|
|
fprintf(stderr, "failed to register object\n"); \
|
|
exit(1); \
|
|
} \
|
|
(rpc)->request_new = (void *(*)(void))request##_new; \
|
|
(rpc)->request_free = (void (*)(void *))request##_free; \
|
|
(rpc)->request_unmarshal = (int (*)(void *, struct evbuffer *))request##_unmarshal; \
|
|
(rpc)->reply_new = (void *(*)(void))reply##_new; \
|
|
(rpc)->reply_free = (void (*)(void *))reply##_free; \
|
|
(rpc)->reply_complete = (int (*)(void *))reply##_complete; \
|
|
(rpc)->reply_marshal = (void (*)(struct evbuffer*, void *))reply##_marshal; \
|
|
} while (0)
|
|
|
|
struct evrpc_base;
|
|
struct evhttp;
|
|
|
|
/* functions to start up the rpc system */
|
|
|
|
/** Creates a new rpc base from which RPC requests can be received
|
|
*
|
|
* @param server a pointer to an existing HTTP server
|
|
* @return a newly allocated evrpc_base struct
|
|
* @see evrpc_free()
|
|
*/
|
|
struct evrpc_base *evrpc_init(struct evhttp *server);
|
|
|
|
/**
|
|
* Frees the evrpc base
|
|
*
|
|
* For now, you are responsible for making sure that no rpcs are ongoing.
|
|
*
|
|
* @param base the evrpc_base object to be freed
|
|
* @see evrpc_init
|
|
*/
|
|
void evrpc_free(struct evrpc_base *base);
|
|
|
|
/** register RPCs with the HTTP Server
|
|
*
|
|
* registers a new RPC with the HTTP server, each RPC needs to have
|
|
* a unique name under which it can be identified.
|
|
*
|
|
* @param base the evrpc_base structure in which the RPC should be
|
|
* registered.
|
|
* @param name the name of the RPC
|
|
* @param request the name of the RPC request structure
|
|
* @param reply the name of the RPC reply structure
|
|
* @param callback the callback that should be invoked when the RPC
|
|
* is received. The callback has the following prototype
|
|
* void (*callback)(EVRPC_STRUCT(Message)* rpc, void *arg)
|
|
* @param cbarg an additional parameter that can be passed to the callback.
|
|
* The parameter can be used to carry around state.
|
|
*/
|
|
#define EVRPC_REGISTER(base, name, request, reply, callback, cbarg) \
|
|
do { \
|
|
struct evrpc* rpc = (struct evrpc *)calloc(1, sizeof(struct evrpc)); \
|
|
EVRPC_REGISTER_OBJECT(rpc, name, request, reply); \
|
|
evrpc_register_rpc(base, rpc, \
|
|
(void (*)(struct evrpc_req_generic*, void *))callback, cbarg); \
|
|
} while (0)
|
|
|
|
int evrpc_register_rpc(struct evrpc_base *, struct evrpc *,
|
|
void (*)(struct evrpc_req_generic*, void *), void *);
|
|
|
|
/**
|
|
* Unregisters an already registered RPC
|
|
*
|
|
* @param base the evrpc_base object from which to unregister an RPC
|
|
* @param name the name of the rpc to unregister
|
|
* @return -1 on error or 0 when successful.
|
|
* @see EVRPC_REGISTER()
|
|
*/
|
|
#define EVRPC_UNREGISTER(base, name) evrpc_unregister_rpc(base, #name)
|
|
|
|
int evrpc_unregister_rpc(struct evrpc_base *base, const char *name);
|
|
|
|
/*
|
|
* Client-side RPC support
|
|
*/
|
|
|
|
struct evrpc_pool;
|
|
struct evhttp_connection;
|
|
|
|
/**
|
|
* provides information about the completed RPC request.
|
|
*/
|
|
struct evrpc_status {
|
|
#define EVRPC_STATUS_ERR_NONE 0
|
|
#define EVRPC_STATUS_ERR_TIMEOUT 1
|
|
#define EVRPC_STATUS_ERR_BADPAYLOAD 2
|
|
#define EVRPC_STATUS_ERR_UNSTARTED 3
|
|
#define EVRPC_STATUS_ERR_HOOKABORTED 4
|
|
int error;
|
|
|
|
/* for looking at headers or other information */
|
|
struct evhttp_request *http_req;
|
|
};
|
|
|
|
struct evrpc_request_wrapper {
|
|
TAILQ_ENTRY(evrpc_request_wrapper) next;
|
|
|
|
/* pool on which this rpc request is being made */
|
|
struct evrpc_pool *pool;
|
|
|
|
/* connection on which the request is being sent */
|
|
struct evhttp_connection *evcon;
|
|
|
|
/* event for implementing request timeouts */
|
|
struct event ev_timeout;
|
|
|
|
/* the name of the rpc */
|
|
char *name;
|
|
|
|
/* callback */
|
|
void (*cb)(struct evrpc_status*, void *request, void *reply, void *arg);
|
|
void *cb_arg;
|
|
|
|
void *request;
|
|
void *reply;
|
|
|
|
/* unmarshals the buffer into the proper request structure */
|
|
void (*request_marshal)(struct evbuffer *, void *);
|
|
|
|
/* removes all stored state in the reply */
|
|
void (*reply_clear)(void *);
|
|
|
|
/* marshals the reply into a buffer */
|
|
int (*reply_unmarshal)(void *, struct evbuffer*);
|
|
};
|
|
|
|
/** launches an RPC and sends it to the server
|
|
*
|
|
* EVRPC_MAKE_REQUEST() is used by the client to send an RPC to the server.
|
|
*
|
|
* @param name the name of the RPC
|
|
* @param pool the evrpc_pool that contains the connection objects over which
|
|
* the request should be sent.
|
|
* @param request a pointer to the RPC request structure - it contains the
|
|
* data to be sent to the server.
|
|
* @param reply a pointer to the RPC reply structure. It is going to be filled
|
|
* if the request was answered successfully
|
|
* @param cb the callback to invoke when the RPC request has been answered
|
|
* @param cbarg an additional argument to be passed to the client
|
|
* @return 0 on success, -1 on failure
|
|
*/
|
|
#define EVRPC_MAKE_REQUEST(name, pool, request, reply, cb, cbarg) \
|
|
evrpc_send_request_##name(pool, request, reply, cb, cbarg)
|
|
|
|
int evrpc_make_request(struct evrpc_request_wrapper *);
|
|
|
|
/** creates an rpc connection pool
|
|
*
|
|
* a pool has a number of connections associated with it.
|
|
* rpc requests are always made via a pool.
|
|
*
|
|
* @param base a pointer to an struct event_based object; can be left NULL
|
|
* in singled-threaded applications
|
|
* @return a newly allocated struct evrpc_pool object
|
|
* @see evrpc_pool_free()
|
|
*/
|
|
struct evrpc_pool *evrpc_pool_new(struct event_base *base);
|
|
/** frees an rpc connection pool
|
|
*
|
|
* @param pool a pointer to an evrpc_pool allocated via evrpc_pool_new()
|
|
* @see evrpc_pool_new()
|
|
*/
|
|
void evrpc_pool_free(struct evrpc_pool *pool);
|
|
/*
|
|
* adds a connection over which rpc can be dispatched. the connection
|
|
* object must have been newly created.
|
|
*/
|
|
void evrpc_pool_add_connection(struct evrpc_pool *,
|
|
struct evhttp_connection *);
|
|
|
|
/**
|
|
* Sets the timeout in secs after which a request has to complete. The
|
|
* RPC is completely aborted if it does not complete by then. Setting
|
|
* the timeout to 0 means that it never timeouts and can be used to
|
|
* implement callback type RPCs.
|
|
*
|
|
* Any connection already in the pool will be updated with the new
|
|
* timeout. Connections added to the pool after set_timeout has be
|
|
* called receive the pool timeout only if no timeout has been set
|
|
* for the connection itself.
|
|
*
|
|
* @param pool a pointer to a struct evrpc_pool object
|
|
* @param timeout_in_secs the number of seconds after which a request should
|
|
* timeout and a failure be returned to the callback.
|
|
*/
|
|
void evrpc_pool_set_timeout(struct evrpc_pool *pool, int timeout_in_secs);
|
|
|
|
/**
|
|
* Hooks for changing the input and output of RPCs; this can be used to
|
|
* implement compression, authentication, encryption, ...
|
|
*/
|
|
|
|
enum EVRPC_HOOK_TYPE {
|
|
INPUT, /**< apply the function to an input hook */
|
|
OUTPUT /**< apply the function to an output hook */
|
|
};
|
|
|
|
/** adds a processing hook to either an rpc base or rpc pool
|
|
*
|
|
* If a hook returns -1, the processing is aborted.
|
|
*
|
|
* The add functions return handles that can be used for removing hooks.
|
|
*
|
|
* @param vbase a pointer to either struct evrpc_base or struct evrpc_pool
|
|
* @param hook_type either INPUT or OUTPUT
|
|
* @param cb the callback to call when the hook is activated
|
|
* @param cb_arg an additional argument for the callback
|
|
* @return a handle to the hook so it can be removed later
|
|
* @see evrpc_remove_hook()
|
|
*/
|
|
void *evrpc_add_hook(void *vbase,
|
|
enum EVRPC_HOOK_TYPE hook_type,
|
|
int (*cb)(struct evhttp_request *, struct evbuffer *, void *),
|
|
void *cb_arg);
|
|
|
|
/** removes a previously added hook
|
|
*
|
|
* @param vbase a pointer to either struct evrpc_base or struct evrpc_pool
|
|
* @param hook_type either INPUT or OUTPUT
|
|
* @param handle a handle returned by evrpc_add_hook()
|
|
* @return 1 on success or 0 on failure
|
|
* @see evrpc_add_hook()
|
|
*/
|
|
int evrpc_remove_hook(void *vbase,
|
|
enum EVRPC_HOOK_TYPE hook_type,
|
|
void *handle);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* _EVRPC_H_ */
|