alias_cuseeme.c revision 131699
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 131699 2004-07-06 12:13:28Z des $"); 31 32#include <stdio.h> 33#include <sys/types.h> 34#include <netinet/in_systm.h> 35#include <netinet/in.h> 36#include <netinet/ip.h> 37#include <netinet/udp.h> 38 39#include "alias_local.h" 40 41/* CU-SeeMe Data Header */ 42struct cu_header { 43 u_int16_t dest_family; 44 u_int16_t dest_port; 45 u_int32_t dest_addr; 46 int16_t family; 47 u_int16_t port; 48 u_int32_t addr; 49 u_int32_t seq; 50 u_int16_t msg; 51 u_int16_t data_type; 52 u_int16_t packet_len; 53}; 54 55/* Open Continue Header */ 56struct oc_header { 57 u_int16_t client_count; /* Number of client info structs */ 58 u_int32_t seq_no; 59 char user_name [20]; 60 char reserved [4]; /* flags, version stuff, etc */ 61}; 62 63/* client info structures */ 64struct client_info { 65 u_int32_t address;/* Client address */ 66 char reserved [8]; /* Flags, pruning bitfield, packet 67 * counts etc */ 68}; 69 70void 71AliasHandleCUSeeMeOut(struct libalias *la, struct ip *pip, struct alias_link *lnk) 72{ 73 struct udphdr *ud = ip_next(pip); 74 75 if (ntohs(ud->uh_ulen) - sizeof(struct udphdr) >= sizeof(struct cu_header)) { 76 struct cu_header *cu; 77 struct alias_link *cu_lnk; 78 79 cu = udp_next(ud); 80 if (cu->addr) 81 cu->addr = (u_int32_t) GetAliasAddress(lnk).s_addr; 82 83 cu_lnk = FindUdpTcpOut(la, pip->ip_src, GetDestAddress(lnk), 84 ud->uh_dport, 0, IPPROTO_UDP, 1); 85 86#ifndef NO_FW_PUNCH 87 if (cu_lnk) 88 PunchFWHole(cu_lnk); 89#endif 90 } 91} 92 93void 94AliasHandleCUSeeMeIn(struct libalias *la, struct ip *pip, struct in_addr original_addr) 95{ 96 struct in_addr alias_addr; 97 struct udphdr *ud; 98 struct cu_header *cu; 99 struct oc_header *oc; 100 struct client_info *ci; 101 char *end; 102 int i; 103 104 (void)la; 105 alias_addr.s_addr = pip->ip_dst.s_addr; 106 ud = ip_next(pip); 107 cu = udp_next(ud); 108 oc = (struct oc_header *)(cu + 1); 109 ci = (struct client_info *)(oc + 1); 110 end = (char *)ud + ntohs(ud->uh_ulen); 111 112 if ((char *)oc <= end) { 113 if (cu->dest_addr) 114 cu->dest_addr = (u_int32_t) original_addr.s_addr; 115 if (ntohs(cu->data_type) == 101) 116 /* Find and change our address */ 117 for (i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++) 118 if (ci->address == (u_int32_t) alias_addr.s_addr) { 119 ci->address = (u_int32_t) original_addr.s_addr; 120 break; 121 } 122 } 123} 124