alias_cuseeme.c revision 50476
1/*- 2 * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org> 3 * with the aid of code written by 4 * Junichi SATOH <junichi@astec.co.jp> 1996, 1997. 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 * $FreeBSD: head/sys/netinet/libalias/alias_cuseeme.c 50476 1999-08-28 00:22:10Z peter $ 29 */ 30 31#include <sys/types.h> 32#include <netinet/in_systm.h> 33#include <netinet/in.h> 34#include <netinet/ip.h> 35#include <netinet/udp.h> 36 37#include "alias_local.h" 38 39/* CU-SeeMe Data Header */ 40struct cu_header { 41 u_int16_t dest_family; 42 u_int16_t dest_port; 43 u_int32_t dest_addr; 44 int16_t family; 45 u_int16_t port; 46 u_int32_t addr; 47 u_int32_t seq; 48 u_int16_t msg; 49 u_int16_t data_type; 50 u_int16_t packet_len; 51}; 52 53/* Open Continue Header */ 54struct oc_header { 55 u_int16_t client_count; /* Number of client info structs */ 56 u_int32_t seq_no; 57 char user_name[20]; 58 char reserved[4]; /* flags, version stuff, etc */ 59}; 60 61/* client info structures */ 62struct client_info { 63 u_int32_t address; /* Client address */ 64 char reserved[8]; /* Flags, pruning bitfield, packet counts etc */ 65}; 66 67void 68AliasHandleCUSeeMeOut(struct ip *pip, struct alias_link *link) 69{ 70 struct udphdr *ud; 71 72 ud = (struct udphdr *)((char *)pip + (pip->ip_hl << 2)); 73 if(ud->uh_ulen >= sizeof(struct cu_header)) { 74 struct cu_header *cu; 75 struct alias_link *cu_link; 76 77 cu = (struct cu_header *)(ud + 1); 78 if (cu->addr) 79 cu->addr = (u_int32_t)GetAliasAddress(link).s_addr; 80 81 cu_link = FindUdpTcpOut(pip->ip_src, GetDestAddress(link), 82 ud->uh_dport, 0, IPPROTO_UDP); 83 84#ifndef NO_FW_PUNCH 85 if (cu_link) 86 PunchFWHole(cu_link); 87#endif 88 } 89} 90 91void 92AliasHandleCUSeeMeIn(struct ip *pip, struct in_addr original_addr) 93{ 94 struct in_addr alias_addr; 95 struct udphdr *ud; 96 struct cu_header *cu; 97 struct oc_header *oc; 98 struct client_info *ci; 99 char *end; 100 int i; 101 102 alias_addr.s_addr = pip->ip_dst.s_addr; 103 ud = (struct udphdr *)((char *)pip + (pip->ip_hl << 2)); 104 cu = (struct cu_header *)(ud + 1); 105 oc = (struct oc_header *)(cu + 1); 106 ci = (struct client_info *)(oc + 1); 107 end = (char *)cu + ud->uh_ulen; 108 109 if ((char *)oc <= end) { 110 if(cu->dest_addr) 111 cu->dest_addr = (u_int32_t)original_addr.s_addr; 112 if(ntohs(cu->data_type) == 101) 113 /* Find and change our address */ 114 for(i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++) 115 if(ci->address == (u_int32_t)alias_addr.s_addr) { 116 ci->address = (u_int32_t)original_addr.s_addr; 117 break; 118 } 119 } 120} 121