alias_cuseeme.c revision 145932
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 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: head/sys/netinet/libalias/alias_cuseeme.c 145932 2005-05-05 21:55:17Z glebius $"); 31 32#ifdef _KERNEL 33#include <sys/param.h> 34#else 35#include <sys/types.h> 36#include <stdio.h> 37#endif 38 39#include <netinet/in_systm.h> 40#include <netinet/in.h> 41#include <netinet/ip.h> 42#include <netinet/udp.h> 43 44#ifdef _KERNEL 45#include <netinet/libalias/alias.h> 46#include <netinet/libalias/alias_local.h> 47#else 48#include "alias_local.h" 49#endif 50 51/* CU-SeeMe Data Header */ 52struct cu_header { 53 u_int16_t dest_family; 54 u_int16_t dest_port; 55 u_int32_t dest_addr; 56 int16_t family; 57 u_int16_t port; 58 u_int32_t addr; 59 u_int32_t seq; 60 u_int16_t msg; 61 u_int16_t data_type; 62 u_int16_t packet_len; 63}; 64 65/* Open Continue Header */ 66struct oc_header { 67 u_int16_t client_count; /* Number of client info structs */ 68 u_int32_t seq_no; 69 char user_name [20]; 70 char reserved [4]; /* flags, version stuff, etc */ 71}; 72 73/* client info structures */ 74struct client_info { 75 u_int32_t address;/* Client address */ 76 char reserved [8]; /* Flags, pruning bitfield, packet 77 * counts etc */ 78}; 79 80void 81AliasHandleCUSeeMeOut(struct libalias *la, struct ip *pip, struct alias_link *lnk) 82{ 83 struct udphdr *ud = ip_next(pip); 84 85 if (ntohs(ud->uh_ulen) - sizeof(struct udphdr) >= sizeof(struct cu_header)) { 86 struct cu_header *cu; 87 struct alias_link *cu_lnk; 88 89 cu = udp_next(ud); 90 if (cu->addr) 91 cu->addr = (u_int32_t) GetAliasAddress(lnk).s_addr; 92 93 cu_lnk = FindUdpTcpOut(la, pip->ip_src, GetDestAddress(lnk), 94 ud->uh_dport, 0, IPPROTO_UDP, 1); 95 96#ifndef NO_FW_PUNCH 97 if (cu_lnk) 98 PunchFWHole(cu_lnk); 99#endif 100 } 101} 102 103void 104AliasHandleCUSeeMeIn(struct libalias *la, struct ip *pip, struct in_addr original_addr) 105{ 106 struct in_addr alias_addr; 107 struct udphdr *ud; 108 struct cu_header *cu; 109 struct oc_header *oc; 110 struct client_info *ci; 111 char *end; 112 int i; 113 114 (void)la; 115 alias_addr.s_addr = pip->ip_dst.s_addr; 116 ud = ip_next(pip); 117 cu = udp_next(ud); 118 oc = (struct oc_header *)(cu + 1); 119 ci = (struct client_info *)(oc + 1); 120 end = (char *)ud + ntohs(ud->uh_ulen); 121 122 if ((char *)oc <= end) { 123 if (cu->dest_addr) 124 cu->dest_addr = (u_int32_t) original_addr.s_addr; 125 if (ntohs(cu->data_type) == 101) 126 /* Find and change our address */ 127 for (i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++) 128 if (ci->address == (u_int32_t) alias_addr.s_addr) { 129 ci->address = (u_int32_t) original_addr.s_addr; 130 break; 131 } 132 } 133} 134