154 lines
4.0 KiB
C
154 lines
4.0 KiB
C
/*-
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* Copyright (c) 2005 Paolo Pisati <piso@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Alias_dummy is just an empty skeleton used to demostrate how to write
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* a module for libalias, that will run unalterated in userland or in
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* kernel land.
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*/
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#ifdef _KERNEL
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#else
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#include <errno.h>
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#include <sys/types.h>
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#include <stdio.h>
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#endif
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#include <netinet/in_systm.h>
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#include <netinet/in.h>
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#include <netinet/ip.h>
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#include <netinet/udp.h>
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#ifdef _KERNEL
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#include <netinet/libalias/alias_local.h>
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#include <netinet/libalias/alias_mod.h>
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#else
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#include "alias_local.h"
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#include "alias_mod.h"
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#endif
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static void
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AliasHandleDummy(struct libalias *la, struct ip *ip, struct alias_data *ah);
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static int
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fingerprint(struct libalias *la, struct alias_data *ah)
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{
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/*
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* Check here all the data that will be used later, if any field
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* is empy/NULL, return a -1 value.
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*/
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if (ah->dport == NULL || ah->sport == NULL || ah->lnk == NULL ||
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ah->maxpktsize == 0)
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return (-1);
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/*
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* Fingerprint the incoming packet, if it matches any conditions
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* return an OK value.
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*/
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if (ntohs(*ah->dport) == 123
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|| ntohs(*ah->sport) == 456)
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return (0); /* I know how to handle it. */
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return (-1); /* I don't recognize this packet. */
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}
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/*
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* Wrap in this general purpose function, the real function used to alias the
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* packets.
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*/
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static int
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protohandler(struct libalias *la, struct ip *pip, struct alias_data *ah)
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{
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AliasHandleDummy(la, pip, ah);
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return (0);
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}
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/*
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* NOTA BENE: the next variable MUST NOT be renamed in any case if you want
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* your module to work in userland, cause it's used to find and use all
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* the protocol handlers present in every module.
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* So WATCH OUT, your module needs this variables and it needs it with
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* ITS EXACT NAME: handlers.
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*/
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struct proto_handler handlers [] = {
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{
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.pri = 666,
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.dir = IN|OUT,
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.proto = UDP|TCP,
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.fingerprint = &fingerprint,
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.protohandler = &protohandler
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},
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{ EOH }
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};
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static int
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mod_handler(module_t mod, int type, void *data)
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{
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int error;
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switch (type) {
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case MOD_LOAD:
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error = 0;
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LibAliasAttachHandlers(handlers);
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break;
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case MOD_UNLOAD:
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error = 0;
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LibAliasDetachHandlers(handlers);
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break;
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default:
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error = EINVAL;
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}
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return (error);
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}
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#ifdef _KERNEL
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static
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#endif
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moduledata_t alias_mod = {
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"alias_dummy", mod_handler, NULL
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};
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#ifdef _KERNEL
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DECLARE_MODULE(alias_dummy, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
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MODULE_VERSION(alias_dummy, 1);
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MODULE_DEPEND(alias_dummy, libalias, 1, 1, 1);
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#endif
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static void
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AliasHandleDummy(struct libalias *la, struct ip *ip, struct alias_data *ah)
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{
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; /* Dummy. */
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}
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