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: releng/11.0/sys/netinet/libalias/alias_dummy.c 259858 2013-12-25 02:06:57Z glebius $");
29
30/*
31 * Alias_dummy is just an empty skeleton used to demostrate how to write
32 * a module for libalias, that will run unalterated in userland or in
33 * kernel land.
34 */
35
36#ifdef _KERNEL
37#include <sys/param.h>
38#include <sys/kernel.h>
39#include <sys/module.h>
40#else
41#include <errno.h>
42#include <sys/types.h>
43#include <stdio.h>
44#endif
45
46#include <netinet/in_systm.h>
47#include <netinet/in.h>
48#include <netinet/ip.h>
49#include <netinet/udp.h>
50
51#ifdef _KERNEL
52#include <netinet/libalias/alias_local.h>
53#include <netinet/libalias/alias_mod.h>
54#else
55#include "alias_local.h"
56#include "alias_mod.h"
57#endif
58
59static void
60AliasHandleDummy(struct libalias *la, struct ip *ip, struct alias_data *ah);
61
62static int
63fingerprint(struct libalias *la, struct alias_data *ah)
64{
65
66	/*
67	 * Check here all the data that will be used later, if any field
68	 * is empy/NULL, return a -1 value.
69	 */
70	if (ah->dport == NULL || ah->sport == NULL || ah->lnk == NULL ||
71		ah->maxpktsize == 0)
72		return (-1);
73	/*
74	 * Fingerprint the incoming packet, if it matches any conditions
75	 * return an OK value.
76	 */
77	if (ntohs(*ah->dport) == 123
78	    || ntohs(*ah->sport) == 456)
79		return (0); /* I know how to handle it. */
80	return (-1); /* I don't recognize this packet. */
81}
82
83/*
84 * Wrap in this general purpose function, the real function used to alias the
85 * packets.
86 */
87
88static int
89protohandler(struct libalias *la, struct ip *pip, struct alias_data *ah)
90{
91
92	AliasHandleDummy(la, pip, ah);
93	return (0);
94}
95
96/*
97 * NOTA BENE: the next variable MUST NOT be renamed in any case if you want
98 * your module to work in userland, cause it's used to find and use all
99 * the protocol handlers present in every module.
100 * So WATCH OUT, your module needs this variables and it needs it with
101 * ITS EXACT NAME: handlers.
102 */
103
104struct proto_handler handlers [] = {
105	{
106	  .pri = 666,
107	  .dir = IN|OUT,
108	  .proto = UDP|TCP,
109	  .fingerprint = &fingerprint,
110	  .protohandler = &protohandler
111	},
112	{ EOH }
113};
114
115static int
116mod_handler(module_t mod, int type, void *data)
117{
118	int error;
119
120	switch (type) {
121	case MOD_LOAD:
122		error = 0;
123		LibAliasAttachHandlers(handlers);
124		break;
125	case MOD_UNLOAD:
126		error = 0;
127		LibAliasDetachHandlers(handlers);
128		break;
129	default:
130		error = EINVAL;
131	}
132	return (error);
133}
134
135#ifdef _KERNEL
136static
137#endif
138moduledata_t alias_mod = {
139       "alias_dummy", mod_handler, NULL
140};
141
142#ifdef	_KERNEL
143DECLARE_MODULE(alias_dummy, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
144MODULE_VERSION(alias_dummy, 1);
145MODULE_DEPEND(alias_dummy, libalias, 1, 1, 1);
146#endif
147
148static void
149AliasHandleDummy(struct libalias *la, struct ip *ip, struct alias_data *ah)
150{
151	; /* Dummy. */
152}
153
154