alias/alias_cuseeme.c

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*-
  26  * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org>
  27  *                    with the aid of code written by
  28  *                    Junichi SATOH <junichi@astec.co.jp> 1996, 1997.
  29  * All rights reserved.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  *
  52  * Based upon:
  53  * $FreeBSD: src/lib/libalias/alias_cuseeme.c,v 1.2.2.2 2000/10/31 08:48:21 ru Exp $
  54  */
  55
  56 #include <sys/types.h>
  57 #include <netinet/in_systm.h>
  58 #include <netinet/in.h>
  59 #include <netinet/ip.h>
  60 #include <netinet/udp.h>
  61
  62 #include "alias_local.h"
  63
  64 /* CU-SeeMe Data Header */
  65 struct cu_header {
  66     u_int16_t dest_family;
  67     u_int16_t dest_port;
  68     u_int32_t  dest_addr;
  69     int16_t family;
  70     u_int16_t port;
  71     u_int32_t addr;
  72     u_int32_t seq;
  73     u_int16_t msg;
  74     u_int16_t data_type;
  75     u_int16_t packet_len;
  76 };
  77
  78 /* Open Continue Header */
  79 struct oc_header {
  80     u_int16_t client_count;    /* Number of client info structs */
  81     u_int32_t seq_no;
  82     char user_name[20];
  83     char reserved[4];        /* flags, version stuff, etc */
  84 };
  85
  86 /* client info structures */
  87 struct client_info {
  88     u_int32_t address;          /* Client address */
  89     char reserved[8];        /* Flags, pruning bitfield, packet counts etc */
  90 };
  91
  92 void
  93 AliasHandleCUSeeMeOut(struct ip *pip, struct alias_link *link)
  94 {
  95   struct udphdr *ud;
  96
  97   ud = (struct udphdr *)((char *)pip + (pip->ip_hl << 2));
  98   if (ntohs(ud->uh_ulen) - sizeof(struct udphdr) >= sizeof(struct cu_header)) {
  99     struct cu_header *cu;
 100     struct alias_link *cu_link;
 101
 102     cu = (struct cu_header *)(ud + 1);
 103     if (cu->addr)
 104       cu->addr = (u_int32_t)GetAliasAddress(link).s_addr;
 105
 106     cu_link = FindUdpTcpOut(pip->ip_src, GetDestAddress(link),
 107                             ud->uh_dport, 0, IPPROTO_UDP, 1);
 108
 109 #ifndef NO_FW_PUNCH
 110     if (cu_link)
 111         PunchFWHole(cu_link);
 112 #endif
 113   }
 114 }
 115
 116 void
 117 AliasHandleCUSeeMeIn(struct ip *pip, struct in_addr original_addr)
 118 {
 119   struct in_addr alias_addr;
 120   struct udphdr *ud;
 121   struct cu_header *cu;
 122   struct oc_header *oc;
 123   struct client_info *ci;
 124   char *end;
 125   int i;
 126
 127   alias_addr.s_addr = pip->ip_dst.s_addr;
 128   ud = (struct udphdr *)((char *)pip + (pip->ip_hl << 2));
 129   cu = (struct cu_header *)(ud + 1);
 130   oc = (struct oc_header *)(cu + 1);
 131   ci = (struct client_info *)(oc + 1);
 132   end = (char *)ud + ntohs(ud->uh_ulen);
 133
 134   if ((char *)oc <= end) {
 135     if(cu->dest_addr)
 136       cu->dest_addr = (u_int32_t)original_addr.s_addr;
 137     if(ntohs(cu->data_type) == 101)
 138       /* Find and change our address */
 139       for(i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++)
 140         if(ci->address == (u_int32_t)alias_addr.s_addr) {
 141           ci->address = (u_int32_t)original_addr.s_addr;
 142           break;
 143         }
 144   }
 145 }