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      1 /*
      2  * Copyright (c) 2006-2007 Niels Provos <provos (at) citi.umich.edu>
      3  * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. The name of the author may not be used to endorse or promote products
     14  *    derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 #ifndef EVRPC_INTERNAL_H_INCLUDED_
     28 #define EVRPC_INTERNAL_H_INCLUDED_
     29 
     30 #include "event2/http.h"
     31 #include "http-internal.h"
     32 
     33 struct evrpc;
     34 struct evrpc_request_wrapper;
     35 
     36 #define EVRPC_URI_PREFIX "/.rpc."
     37 
     38 struct evrpc_hook {
     39 	TAILQ_ENTRY(evrpc_hook) next;
     40 
     41 	/* returns EVRPC_TERMINATE; if the rpc should be aborted.
     42 	 * a hook is is allowed to rewrite the evbuffer
     43 	 */
     44 	int (*process)(void *, struct evhttp_request *,
     45 	    struct evbuffer *, void *);
     46 	void *process_arg;
     47 };
     48 
     49 TAILQ_HEAD(evrpc_hook_list, evrpc_hook);
     50 
     51 /*
     52  * this is shared between the base and the pool, so that we can reuse
     53  * the hook adding functions; we alias both evrpc_pool and evrpc_base
     54  * to this common structure.
     55  */
     56 
     57 struct evrpc_hook_ctx;
     58 TAILQ_HEAD(evrpc_pause_list, evrpc_hook_ctx);
     59 
     60 struct evrpc_hooks_ {
     61 	/* hooks for processing outbound and inbound rpcs */
     62 	struct evrpc_hook_list in_hooks;
     63 	struct evrpc_hook_list out_hooks;
     64 
     65 	struct evrpc_pause_list pause_requests;
     66 };
     67 
     68 #define input_hooks common.in_hooks
     69 #define output_hooks common.out_hooks
     70 #define paused_requests common.pause_requests
     71 
     72 struct evrpc_base {
     73 	struct evrpc_hooks_ common;
     74 
     75 	/* the HTTP server under which we register our RPC calls */
     76 	struct evhttp* http_server;
     77 
     78 	/* a list of all RPCs registered with us */
     79 	TAILQ_HEAD(evrpc_list, evrpc) registered_rpcs;
     80 };
     81 
     82 struct evrpc_req_generic;
     83 void evrpc_reqstate_free_(struct evrpc_req_generic* rpc_state);
     84 
     85 /* A pool for holding evhttp_connection objects */
     86 struct evrpc_pool {
     87 	struct evrpc_hooks_ common;
     88 
     89 	struct event_base *base;
     90 
     91 	struct evconq connections;
     92 
     93 	int timeout;
     94 
     95 	TAILQ_HEAD(evrpc_requestq, evrpc_request_wrapper) (requests);
     96 };
     97 
     98 struct evrpc_hook_ctx {
     99 	TAILQ_ENTRY(evrpc_hook_ctx) next;
    100 
    101 	void *ctx;
    102 	void (*cb)(void *, enum EVRPC_HOOK_RESULT);
    103 };
    104 
    105 struct evrpc_meta {
    106 	TAILQ_ENTRY(evrpc_meta) next;
    107 	char *key;
    108 
    109 	void *data;
    110 	size_t data_size;
    111 };
    112 
    113 TAILQ_HEAD(evrpc_meta_list, evrpc_meta);
    114 
    115 struct evrpc_hook_meta {
    116 	struct evrpc_meta_list meta_data;
    117 	struct evhttp_connection *evcon;
    118 };
    119 
    120 /* allows association of meta data with a request */
    121 static void evrpc_hook_associate_meta_(struct evrpc_hook_meta **pctx,
    122     struct evhttp_connection *evcon);
    123 
    124 /* creates a new meta data store */
    125 static struct evrpc_hook_meta *evrpc_hook_meta_new_(void);
    126 
    127 /* frees the meta data associated with a request */
    128 static void evrpc_hook_context_free_(struct evrpc_hook_meta *ctx);
    129 
    130 /* the server side of an rpc */
    131 
    132 /* We alias the RPC specific structs to this voided one */
    133 struct evrpc_req_generic {
    134 	/*
    135 	 * allows association of meta data via hooks - needs to be
    136 	 * synchronized with evrpc_request_wrapper
    137 	 */
    138 	struct evrpc_hook_meta *hook_meta;
    139 
    140 	/* the unmarshaled request object */
    141 	void *request;
    142 
    143 	/* the empty reply object that needs to be filled in */
    144 	void *reply;
    145 
    146 	/*
    147 	 * the static structure for this rpc; that can be used to
    148 	 * automatically unmarshal and marshal the http buffers.
    149 	 */
    150 	struct evrpc *rpc;
    151 
    152 	/*
    153 	 * the http request structure on which we need to answer.
    154 	 */
    155 	struct evhttp_request* http_req;
    156 
    157 	/*
    158 	 * Temporary data store for marshaled data
    159 	 */
    160 	struct evbuffer* rpc_data;
    161 };
    162 
    163 /* the client side of an rpc request */
    164 struct evrpc_request_wrapper {
    165 	/*
    166 	 * allows association of meta data via hooks - needs to be
    167 	 * synchronized with evrpc_req_generic.
    168 	 */
    169 	struct evrpc_hook_meta *hook_meta;
    170 
    171 	TAILQ_ENTRY(evrpc_request_wrapper) next;
    172 
    173 	/* pool on which this rpc request is being made */
    174 	struct evrpc_pool *pool;
    175 
    176 	/* connection on which the request is being sent */
    177 	struct evhttp_connection *evcon;
    178 
    179 	/* the actual  request */
    180 	struct evhttp_request *req;
    181 
    182 	/* event for implementing request timeouts */
    183 	struct event ev_timeout;
    184 
    185 	/* the name of the rpc */
    186 	char *name;
    187 
    188 	/* callback */
    189 	void (*cb)(struct evrpc_status*, void *request, void *reply, void *arg);
    190 	void *cb_arg;
    191 
    192 	void *request;
    193 	void *reply;
    194 
    195 	/* unmarshals the buffer into the proper request structure */
    196 	void (*request_marshal)(struct evbuffer *, void *);
    197 
    198 	/* removes all stored state in the reply */
    199 	void (*reply_clear)(void *);
    200 
    201 	/* marshals the reply into a buffer */
    202 	int (*reply_unmarshal)(void *, struct evbuffer*);
    203 };
    204 
    205 #endif /* EVRPC_INTERNAL_H_INCLUDED_ */
    206