1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2005 Paolo Pisati <piso@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 */
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#ifdef _KERNEL
33#include <sys/libkern.h>
34#include <sys/param.h>
35#include <sys/lock.h>
36#include <sys/rwlock.h>
37#else
38#include <stdio.h>
39#include <string.h>
40#include <sys/types.h>
41#include <errno.h>
42#endif
43
44#include <netinet/in_systm.h>
45#include <netinet/in.h>
46#include <netinet/ip.h>
47
48#ifdef _KERNEL
49#include <netinet/libalias/alias_local.h>
50#include <netinet/libalias/alias_mod.h>
51#else
52#include "alias_local.h"
53#include "alias_mod.h"
54#endif
55
56/* Protocol and userland module handlers chains. */
57static TAILQ_HEAD(handler_chain, proto_handler) handler_chain =
58    TAILQ_HEAD_INITIALIZER(handler_chain);
59
60static int
61attach_handler(struct proto_handler *p)
62{
63	struct proto_handler *b;
64
65	TAILQ_FOREACH(b, &handler_chain, link) {
66		if ((b->pri == p->pri) &&
67		    (b->dir == p->dir) &&
68		    (b->proto == p->proto))
69			return (EEXIST);
70		if (b->pri > p->pri) {
71			TAILQ_INSERT_BEFORE(b, p, link);
72			return (0);
73		}
74	}
75
76	TAILQ_INSERT_TAIL(&handler_chain, p, link);
77
78	return (0);
79}
80
81int
82LibAliasAttachHandlers(struct proto_handler *p)
83{
84	int error;
85
86	while (p->dir != NODIR) {
87		error = attach_handler(p);
88		if (error)
89			return (error);
90		p++;
91	}
92
93	return (0);
94}
95
96/* XXXGL: should be void, but no good reason to break ABI */
97int
98LibAliasDetachHandlers(struct proto_handler *p)
99{
100	while (p->dir != NODIR) {
101		TAILQ_REMOVE(&handler_chain, p, link);
102		p++;
103	}
104
105	return (0);
106}
107
108int
109find_handler(int8_t dir, int8_t proto, struct libalias *la, struct ip *ip,
110    struct alias_data *ad)
111{
112	struct proto_handler *p;
113
114	TAILQ_FOREACH(p, &handler_chain, link)
115		if ((p->dir & dir) && (p->proto & proto) &&
116		    p->fingerprint(la, ad) == 0)
117			return (p->protohandler(la, ip, ad));
118
119	return (ENOENT);
120}
121
122struct proto_handler *
123first_handler(void)
124{
125	return (TAILQ_FIRST(&handler_chain));
126}
127
128#ifndef _KERNEL
129/* Dll manipulation code - this code is not thread safe... */
130static SLIST_HEAD(dll_chain, dll) dll_chain = SLIST_HEAD_INITIALIZER(dll_chain);
131int
132attach_dll(struct dll *p)
133{
134	struct dll *b;
135
136	SLIST_FOREACH(b, &dll_chain, next) {
137		if (!strncmp(b->name, p->name, DLL_LEN))
138			return (EEXIST); /* Dll name conflict. */
139	}
140	SLIST_INSERT_HEAD(&dll_chain, p, next);
141	return (0);
142}
143
144void *
145detach_dll(char *p)
146{
147	struct dll *b, *b_tmp;
148	void *error;
149
150	b = NULL;
151	error = NULL;
152	SLIST_FOREACH_SAFE(b, &dll_chain, next, b_tmp)
153		if (!strncmp(b->name, p, DLL_LEN)) {
154			SLIST_REMOVE(&dll_chain, b, dll, next);
155			error = b;
156			break;
157		}
158	return (error);
159}
160
161struct dll *
162walk_dll_chain(void)
163{
164	struct dll *t;
165
166	t = SLIST_FIRST(&dll_chain);
167	if (t == NULL)
168		return (NULL);
169	SLIST_REMOVE_HEAD(&dll_chain, next);
170	return (t);
171}
172#endif /* !_KERNEL */
173