sys/net/libalias/alias_dummy.c

   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: src/sys/netinet/libalias/alias_dummy.c,v 1.1.6.1 2008/11/25 02:59:29 kensmith Exp $");
  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
  59 static void
  60 AliasHandleDummy(struct libalias *la, struct ip *ip, struct alias_data *ah);
  61
  62 static int
  63 fingerprint(struct libalias *la, struct ip *pip, 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
  88 static int
  89 protohandler(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
 104 struct 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
 115 static int
 116 mod_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
 136 static
 137 #endif
 138 moduledata_t alias_mod = {
 139            "alias_dummy", mod_handler, NULL
 140 };
 141
 142 #ifdef  _KERNEL
 143 DECLARE_MODULE(alias_dummy, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
 144 MODULE_VERSION(alias_dummy, 1);
 145 MODULE_DEPEND(alias_dummy, libalias, 1, 1, 1);
 146 #endif
 147
 148 static void
 149 AliasHandleDummy(struct libalias *la, struct ip *ip, struct alias_data *ah)
 150 {
 151         ; /* Dummy. */
 152 }