1 /*
2  * Copyright (c) 2003+ Evgeniy Polyakov <johnpol@2ka.mxt.ru>
3  *
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #ifndef _XT_OSF_H
20 #define _XT_OSF_H
21 
22 #include <linux/types.h>
23 
24 #define MAXGENRELEN		32
25 
26 #define XT_OSF_GENRE		(1<<0)
27 #define	XT_OSF_TTL		(1<<1)
28 #define XT_OSF_LOG		(1<<2)
29 #define XT_OSF_INVERT		(1<<3)
30 
31 #define XT_OSF_LOGLEVEL_ALL	0	/* log all matched fingerprints */
32 #define XT_OSF_LOGLEVEL_FIRST	1	/* log only the first matced fingerprint */
33 #define XT_OSF_LOGLEVEL_ALL_KNOWN	2 /* do not log unknown packets */
34 
35 #define XT_OSF_TTL_TRUE		0	/* True ip and fingerprint TTL comparison */
36 #define XT_OSF_TTL_LESS		1	/* Check if ip TTL is less than fingerprint one */
37 #define XT_OSF_TTL_NOCHECK	2	/* Do not compare ip and fingerprint TTL at all */
38 
39 struct xt_osf_info {
40 	char			genre[MAXGENRELEN];
41 	__u32			len;
42 	__u32			flags;
43 	__u32			loglevel;
44 	__u32			ttl;
45 };
46 
47 /*
48  * Wildcard MSS (kind of).
49  * It is used to implement a state machine for the different wildcard values
50  * of the MSS and window sizes.
51  */
52 struct xt_osf_wc {
53 	__u32			wc;
54 	__u32			val;
55 };
56 
57 /*
58  * This struct represents IANA options
59  * http://www.iana.org/assignments/tcp-parameters
60  */
61 struct xt_osf_opt {
62 	__u16			kind, length;
63 	struct xt_osf_wc	wc;
64 };
65 
66 struct xt_osf_user_finger {
67 	struct xt_osf_wc	wss;
68 
69 	__u8			ttl, df;
70 	__u16			ss, mss;
71 	__u16			opt_num;
72 
73 	char			genre[MAXGENRELEN];
74 	char			version[MAXGENRELEN];
75 	char			subtype[MAXGENRELEN];
76 
77 	/* MAX_IPOPTLEN is maximum if all options are NOPs or EOLs */
78 	struct xt_osf_opt	opt[MAX_IPOPTLEN];
79 };
80 
81 struct xt_osf_nlmsg {
82 	struct xt_osf_user_finger	f;
83 	struct iphdr		ip;
84 	struct tcphdr		tcp;
85 };
86 
87 /* Defines for IANA option kinds */
88 
89 enum iana_options {
90 	OSFOPT_EOL = 0,		/* End of options */
91 	OSFOPT_NOP, 		/* NOP */
92 	OSFOPT_MSS, 		/* Maximum segment size */
93 	OSFOPT_WSO, 		/* Window scale option */
94 	OSFOPT_SACKP,		/* SACK permitted */
95 	OSFOPT_SACK,		/* SACK */
96 	OSFOPT_ECHO,
97 	OSFOPT_ECHOREPLY,
98 	OSFOPT_TS,		/* Timestamp option */
99 	OSFOPT_POCP,		/* Partial Order Connection Permitted */
100 	OSFOPT_POSP,		/* Partial Order Service Profile */
101 
102 	/* Others are not used in the current OSF */
103 	OSFOPT_EMPTY = 255,
104 };
105 
106 /*
107  * Initial window size option state machine: multiple of mss, mtu or
108  * plain numeric value. Can also be made as plain numeric value which
109  * is not a multiple of specified value.
110  */
111 enum xt_osf_window_size_options {
112 	OSF_WSS_PLAIN	= 0,
113 	OSF_WSS_MSS,
114 	OSF_WSS_MTU,
115 	OSF_WSS_MODULO,
116 	OSF_WSS_MAX,
117 };
118 
119 /*
120  * Add/remove fingerprint from the kernel.
121  */
122 enum xt_osf_msg_types {
123 	OSF_MSG_ADD,
124 	OSF_MSG_REMOVE,
125 	OSF_MSG_MAX,
126 };
127 
128 enum xt_osf_attr_type {
129 	OSF_ATTR_UNSPEC,
130 	OSF_ATTR_FINGER,
131 	OSF_ATTR_MAX,
132 };
133 
134 #endif				/* _XT_OSF_H */
135