alias_cuseeme.c revision 145921 
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 145921 2005-05-05 19:27:32Z 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_local.h>
46#include <netinet/libalias/alias.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