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1 /*
2  * Copyright (c) 2006-2007 Niels Provos <provos@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