2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org>
5 * with the aid of code written by
6 * Junichi SATOH <junichi@astec.co.jp> 1996, 1997.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/module.h>
40 #include <sys/types.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/in.h>
46 #include <netinet/ip.h>
47 #include <netinet/udp.h>
50 #include <netinet/libalias/alias.h>
51 #include <netinet/libalias/alias_local.h>
52 #include <netinet/libalias/alias_mod.h>
54 #include "alias_local.h"
55 #include "alias_mod.h"
58 #define CUSEEME_PORT_NUMBER 7648
61 AliasHandleCUSeeMeOut(struct libalias *la, struct ip *pip,
62 struct alias_link *lnk);
65 AliasHandleCUSeeMeIn(struct libalias *la, struct ip *pip,
66 struct in_addr original_addr);
69 fingerprint(struct libalias *la, struct alias_data *ah)
72 if (ah->dport == NULL || ah->oaddr == NULL)
74 if (ntohs(*ah->dport) == CUSEEME_PORT_NUMBER)
80 protohandlerin(struct libalias *la, struct ip *pip, struct alias_data *ah)
83 AliasHandleCUSeeMeIn(la, pip, *ah->oaddr);
88 protohandlerout(struct libalias *la, struct ip *pip, struct alias_data *ah)
91 AliasHandleCUSeeMeOut(la, pip, ah->lnk);
95 /* Kernel module definition. */
96 struct proto_handler handlers[] = {
101 .fingerprint = &fingerprint,
102 .protohandler = &protohandlerout
108 .fingerprint = &fingerprint,
109 .protohandler = &protohandlerin
115 mod_handler(module_t mod, int type, void *data)
122 LibAliasAttachHandlers(handlers);
126 LibAliasDetachHandlers(handlers);
139 "alias_cuseeme", mod_handler, NULL
143 DECLARE_MODULE(alias_cuseeme, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
144 MODULE_VERSION(alias_cuseeme, 1);
145 MODULE_DEPEND(alias_cuseeme, libalias, 1, 1, 1);
148 /* CU-SeeMe Data Header */
150 u_int16_t dest_family;
159 u_int16_t packet_len;
162 /* Open Continue Header */
164 u_int16_t client_count; /* Number of client info structs */
167 char reserved [4]; /* flags, version stuff, etc */
170 /* client info structures */
172 u_int32_t address;/* Client address */
173 char reserved [8]; /* Flags, pruning bitfield, packet
178 AliasHandleCUSeeMeOut(struct libalias *la, struct ip *pip, struct alias_link *lnk)
180 struct udphdr *ud = ip_next(pip);
182 if (ntohs(ud->uh_ulen) - sizeof(struct udphdr) >= sizeof(struct cu_header)) {
183 struct cu_header *cu;
184 struct alias_link *cu_lnk;
188 cu->addr = (u_int32_t) GetAliasAddress(lnk).s_addr;
190 cu_lnk = FindUdpTcpOut(la, pip->ip_src, GetDestAddress(lnk),
191 ud->uh_dport, 0, IPPROTO_UDP, 1);
201 AliasHandleCUSeeMeIn(struct libalias *la, struct ip *pip, struct in_addr original_addr)
203 struct in_addr alias_addr;
205 struct cu_header *cu;
206 struct oc_header *oc;
207 struct client_info *ci;
212 alias_addr.s_addr = pip->ip_dst.s_addr;
215 oc = (struct oc_header *)(cu + 1);
216 ci = (struct client_info *)(oc + 1);
217 end = (char *)ud + ntohs(ud->uh_ulen);
219 if ((char *)oc <= end) {
221 cu->dest_addr = (u_int32_t) original_addr.s_addr;
222 if (ntohs(cu->data_type) == 101)
223 /* Find and change our address */
224 for (i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++)
225 if (ci->address == (u_int32_t) alias_addr.s_addr) {
226 ci->address = (u_int32_t) original_addr.s_addr;