1/*-
2 * Copyright (c) 2005 Paolo Pisati <piso@FreeBSD.org>
3 * All rights reserved.
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 */
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#ifdef _KERNEL
31#include <sys/libkern.h>
32#include <sys/param.h>
33#include <sys/lock.h>
34#include <sys/rwlock.h>
35#else
36#include <stdio.h>
37#include <string.h>
38#include <sys/types.h>
39#include <errno.h>
40#endif
41
42#include <netinet/in_systm.h>
43#include <netinet/in.h>
44#include <netinet/ip.h>
45
46#ifdef _KERNEL
47#include <netinet/libalias/alias_local.h>
48#include <netinet/libalias/alias_mod.h>
49#else
50#include "alias_local.h"
51#include "alias_mod.h"
52#endif
53
54/* Protocol and userland module handlers chains. */
55LIST_HEAD(handler_chain, proto_handler) handler_chain = LIST_HEAD_INITIALIZER(handler_chain);
56#ifdef _KERNEL
57struct rwlock   handler_rw;
58#endif
59SLIST_HEAD(dll_chain, dll) dll_chain = SLIST_HEAD_INITIALIZER(dll_chain);
60
61#ifdef _KERNEL
62
63#define	LIBALIAS_RWLOCK_INIT() \
64        rw_init(&handler_rw, "Libalias_modules_rwlock")
65#define	LIBALIAS_RWLOCK_DESTROY()	rw_destroy(&handler_rw)
66#define	LIBALIAS_WLOCK_ASSERT() \
67        rw_assert(&handler_rw, RA_WLOCKED)
68
69static __inline void
70LIBALIAS_RLOCK(void)
71{
72	rw_rlock(&handler_rw);
73}
74
75static __inline void
76LIBALIAS_RUNLOCK(void)
77{
78	rw_runlock(&handler_rw);
79}
80
81static __inline void
82LIBALIAS_WLOCK(void)
83{
84	rw_wlock(&handler_rw);
85}
86
87static __inline void
88LIBALIAS_WUNLOCK(void)
89{
90	rw_wunlock(&handler_rw);
91}
92
93static void
94_handler_chain_init(void)
95{
96
97	if (!rw_initialized(&handler_rw))
98		LIBALIAS_RWLOCK_INIT();
99}
100
101static void
102_handler_chain_destroy(void)
103{
104
105	if (rw_initialized(&handler_rw))
106		LIBALIAS_RWLOCK_DESTROY();
107}
108
109#else
110#define	LIBALIAS_RWLOCK_INIT() ;
111#define	LIBALIAS_RWLOCK_DESTROY()	;
112#define	LIBALIAS_WLOCK_ASSERT()	;
113#define	LIBALIAS_RLOCK() ;
114#define	LIBALIAS_RUNLOCK() ;
115#define	LIBALIAS_WLOCK() ;
116#define	LIBALIAS_WUNLOCK() ;
117#define _handler_chain_init() ;
118#define _handler_chain_destroy() ;
119#endif
120
121void
122handler_chain_init(void)
123{
124	_handler_chain_init();
125}
126
127void
128handler_chain_destroy(void)
129{
130	_handler_chain_destroy();
131}
132
133static int
134_attach_handler(struct proto_handler *p)
135{
136	struct proto_handler *b;
137
138	LIBALIAS_WLOCK_ASSERT();
139	b = NULL;
140	LIST_FOREACH(b, &handler_chain, entries) {
141		if ((b->pri == p->pri) &&
142		    (b->dir == p->dir) &&
143		    (b->proto == p->proto))
144			return (EEXIST); /* Priority conflict. */
145		if (b->pri > p->pri) {
146			LIST_INSERT_BEFORE(b, p, entries);
147			return (0);
148		}
149	}
150	/* End of list or found right position, inserts here. */
151	if (b)
152		LIST_INSERT_AFTER(b, p, entries);
153	else
154		LIST_INSERT_HEAD(&handler_chain, p, entries);
155	return (0);
156}
157
158static int
159_detach_handler(struct proto_handler *p)
160{
161	struct proto_handler *b, *b_tmp;
162
163	LIBALIAS_WLOCK_ASSERT();
164	LIST_FOREACH_SAFE(b, &handler_chain, entries, b_tmp) {
165		if (b == p) {
166			LIST_REMOVE(b, entries);
167			return (0);
168		}
169	}
170	return (ENOENT); /* Handler not found. */
171}
172
173int
174LibAliasAttachHandlers(struct proto_handler *_p)
175{
176	int i, error;
177
178	LIBALIAS_WLOCK();
179	error = -1;
180	for (i = 0; 1; i++) {
181		if (*((int *)&_p[i]) == EOH)
182			break;
183		error = _attach_handler(&_p[i]);
184		if (error != 0)
185			break;
186	}
187	LIBALIAS_WUNLOCK();
188	return (error);
189}
190
191int
192LibAliasDetachHandlers(struct proto_handler *_p)
193{
194	int i, error;
195
196	LIBALIAS_WLOCK();
197	error = -1;
198	for (i = 0; 1; i++) {
199		if (*((int *)&_p[i]) == EOH)
200			break;
201		error = _detach_handler(&_p[i]);
202		if (error != 0)
203			break;
204	}
205	LIBALIAS_WUNLOCK();
206	return (error);
207}
208
209int
210detach_handler(struct proto_handler *_p)
211{
212	int error;
213
214	LIBALIAS_WLOCK();
215	error = -1;
216	error = _detach_handler(_p);
217	LIBALIAS_WUNLOCK();
218	return (error);
219}
220
221int
222find_handler(int8_t dir, int8_t proto, struct libalias *la, __unused struct ip *pip,
223    struct alias_data *ad)
224{
225	struct proto_handler *p;
226	int error;
227
228	LIBALIAS_RLOCK();
229	error = ENOENT;
230	LIST_FOREACH(p, &handler_chain, entries) {
231		if ((p->dir & dir) && (p->proto & proto))
232			if (p->fingerprint(la, ad) == 0) {
233				error = p->protohandler(la, pip, ad);
234				break;
235			}
236	}
237	LIBALIAS_RUNLOCK();
238	return (error);
239}
240
241struct proto_handler *
242first_handler(void)
243{
244
245	return (LIST_FIRST(&handler_chain));
246}
247
248/* Dll manipulation code - this code is not thread safe... */
249
250int
251attach_dll(struct dll *p)
252{
253	struct dll *b;
254
255	SLIST_FOREACH(b, &dll_chain, next) {
256		if (!strncmp(b->name, p->name, DLL_LEN))
257			return (EEXIST); /* Dll name conflict. */
258	}
259	SLIST_INSERT_HEAD(&dll_chain, p, next);
260	return (0);
261}
262
263void *
264detach_dll(char *p)
265{
266	struct dll *b, *b_tmp;
267	void *error;
268
269	b = NULL;
270	error = NULL;
271	SLIST_FOREACH_SAFE(b, &dll_chain, next, b_tmp)
272		if (!strncmp(b->name, p, DLL_LEN)) {
273			SLIST_REMOVE(&dll_chain, b, dll, next);
274			error = b;
275			break;
276		}
277	return (error);
278}
279
280struct dll *
281walk_dll_chain(void)
282{
283	struct dll *t;
284
285	t = SLIST_FIRST(&dll_chain);
286	if (t == NULL)
287		return (NULL);
288	SLIST_REMOVE_HEAD(&dll_chain, next);
289	return (t);
290}
291