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: src/lib/libalias/alias_cuseeme.c,v 1.2.2.2 2000/10/31 08:48:21 ru Exp $ 29 * $DragonFly: src/lib/libalias/alias_cuseeme.c,v 1.3 2004/08/20 01:21:36 joerg Exp $ 30 */ 31 32 #include <sys/param.h> 33 #include <netinet/in_systm.h> 34 #include <netinet/in.h> 35 #include <netinet/ip.h> 36 #include <netinet/udp.h> 37 38 #include "alias_local.h" 39 40 /* CU-SeeMe Data Header */ 41 struct cu_header { 42 u_int16_t dest_family; 43 u_int16_t dest_port; 44 u_int32_t dest_addr; 45 int16_t family; 46 u_int16_t port; 47 u_int32_t addr; 48 u_int32_t seq; 49 u_int16_t msg; 50 u_int16_t data_type; 51 u_int16_t packet_len; 52 }; 53 54 /* Open Continue Header */ 55 struct oc_header { 56 u_int16_t client_count; /* Number of client info structs */ 57 u_int32_t seq_no; 58 char user_name[20]; 59 char reserved[4]; /* flags, version stuff, etc */ 60 }; 61 62 /* client info structures */ 63 struct client_info { 64 u_int32_t address; /* Client address */ 65 char reserved[8]; /* Flags, pruning bitfield, packet counts etc */ 66 }; 67 68 void 69 AliasHandleCUSeeMeOut(struct ip *pip, struct alias_link *link) 70 { 71 struct udphdr *ud; 72 73 ud = (struct udphdr *)((char *)pip + (pip->ip_hl << 2)); 74 if (ntohs(ud->uh_ulen) - sizeof(struct udphdr) >= sizeof(struct cu_header)) { 75 struct cu_header *cu; 76 struct alias_link *cu_link; 77 78 cu = (struct cu_header *)(ud + 1); 79 if (cu->addr) 80 cu->addr = (u_int32_t)GetAliasAddress(link).s_addr; 81 82 cu_link = FindUdpTcpOut(pip->ip_src, GetDestAddress(link), 83 ud->uh_dport, 0, IPPROTO_UDP, 1); 84 85 #ifndef NO_FW_PUNCH 86 if (cu_link) 87 PunchFWHole(cu_link); 88 #endif 89 } 90 } 91 92 void 93 AliasHandleCUSeeMeIn(struct ip *pip, struct in_addr original_addr) 94 { 95 struct in_addr alias_addr; 96 struct udphdr *ud; 97 struct cu_header *cu; 98 struct oc_header *oc; 99 struct client_info *ci; 100 char *end; 101 int i; 102 103 alias_addr.s_addr = pip->ip_dst.s_addr; 104 ud = (struct udphdr *)((char *)pip + (pip->ip_hl << 2)); 105 cu = (struct cu_header *)(ud + 1); 106 oc = (struct oc_header *)(cu + 1); 107 ci = (struct client_info *)(oc + 1); 108 end = (char *)ud + ntohs(ud->uh_ulen); 109 110 if ((char *)oc <= end) { 111 if(cu->dest_addr) 112 cu->dest_addr = (u_int32_t)original_addr.s_addr; 113 if(ntohs(cu->data_type) == 101) 114 /* Find and change our address */ 115 for(i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++) 116 if(ci->address == (u_int32_t)alias_addr.s_addr) { 117 ci->address = (u_int32_t)original_addr.s_addr; 118 break; 119 } 120 } 121 } 122