evrpc-internal.h revision 290001 
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
33struct evrpc;
34struct evrpc_request_wrapper;
35
36#define EVRPC_URI_PREFIX "/.rpc."
37
38struct 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
49TAILQ_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
57struct evrpc_hook_ctx;
58TAILQ_HEAD(evrpc_pause_list, evrpc_hook_ctx);
59
60struct 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
72struct 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
82struct evrpc_req_generic;
83void evrpc_reqstate_free_(struct evrpc_req_generic* rpc_state);
84
85/* A pool for holding evhttp_connection objects */
86struct 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
98struct evrpc_hook_ctx {
99	TAILQ_ENTRY(evrpc_hook_ctx) next;
100
101	void *ctx;
102	void (*cb)(void *, enum EVRPC_HOOK_RESULT);
103};
104
105struct evrpc_meta {
106	TAILQ_ENTRY(evrpc_meta) next;
107	char *key;
108
109	void *data;
110	size_t data_size;
111};
112
113TAILQ_HEAD(evrpc_meta_list, evrpc_meta);
114
115struct 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 */
121static void evrpc_hook_associate_meta_(struct evrpc_hook_meta **pctx,
122    struct evhttp_connection *evcon);
123
124/* creates a new meta data store */
125static struct evrpc_hook_meta *evrpc_hook_meta_new_(void);
126
127/* frees the meta data associated with a request */
128static 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 */
133struct 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 */
164struct 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