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      1 /*
      2  * Copyright (c) 2003+ Evgeniy Polyakov <johnpol (at) 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 #include <linux/ip.h>
     24 #include <linux/tcp.h>
     25 
     26 #define MAXGENRELEN		32
     27 
     28 #define XT_OSF_GENRE		(1<<0)
     29 #define	XT_OSF_TTL		(1<<1)
     30 #define XT_OSF_LOG		(1<<2)
     31 #define XT_OSF_INVERT		(1<<3)
     32 
     33 #define XT_OSF_LOGLEVEL_ALL	0	/* log all matched fingerprints */
     34 #define XT_OSF_LOGLEVEL_FIRST	1	/* log only the first matced fingerprint */
     35 #define XT_OSF_LOGLEVEL_ALL_KNOWN	2 /* do not log unknown packets */
     36 
     37 #define XT_OSF_TTL_TRUE		0	/* True ip and fingerprint TTL comparison */
     38 #define XT_OSF_TTL_LESS		1	/* Check if ip TTL is less than fingerprint one */
     39 #define XT_OSF_TTL_NOCHECK	2	/* Do not compare ip and fingerprint TTL at all */
     40 
     41 struct xt_osf_info {
     42 	char			genre[MAXGENRELEN];
     43 	__u32			len;
     44 	__u32			flags;
     45 	__u32			loglevel;
     46 	__u32			ttl;
     47 };
     48 
     49 /*
     50  * Wildcard MSS (kind of).
     51  * It is used to implement a state machine for the different wildcard values
     52  * of the MSS and window sizes.
     53  */
     54 struct xt_osf_wc {
     55 	__u32			wc;
     56 	__u32			val;
     57 };
     58 
     59 /*
     60  * This struct represents IANA options
     61  * http://www.iana.org/assignments/tcp-parameters
     62  */
     63 struct xt_osf_opt {
     64 	__u16			kind, length;
     65 	struct xt_osf_wc	wc;
     66 };
     67 
     68 struct xt_osf_user_finger {
     69 	struct xt_osf_wc	wss;
     70 
     71 	__u8			ttl, df;
     72 	__u16			ss, mss;
     73 	__u16			opt_num;
     74 
     75 	char			genre[MAXGENRELEN];
     76 	char			version[MAXGENRELEN];
     77 	char			subtype[MAXGENRELEN];
     78 
     79 	/* MAX_IPOPTLEN is maximum if all options are NOPs or EOLs */
     80 	struct xt_osf_opt	opt[MAX_IPOPTLEN];
     81 };
     82 
     83 struct xt_osf_nlmsg {
     84 	struct xt_osf_user_finger	f;
     85 	struct iphdr		ip;
     86 	struct tcphdr		tcp;
     87 };
     88 
     89 /* Defines for IANA option kinds */
     90 
     91 enum iana_options {
     92 	OSFOPT_EOL = 0,		/* End of options */
     93 	OSFOPT_NOP, 		/* NOP */
     94 	OSFOPT_MSS, 		/* Maximum segment size */
     95 	OSFOPT_WSO, 		/* Window scale option */
     96 	OSFOPT_SACKP,		/* SACK permitted */
     97 	OSFOPT_SACK,		/* SACK */
     98 	OSFOPT_ECHO,
     99 	OSFOPT_ECHOREPLY,
    100 	OSFOPT_TS,		/* Timestamp option */
    101 	OSFOPT_POCP,		/* Partial Order Connection Permitted */
    102 	OSFOPT_POSP,		/* Partial Order Service Profile */
    103 
    104 	/* Others are not used in the current OSF */
    105 	OSFOPT_EMPTY = 255,
    106 };
    107 
    108 /*
    109  * Initial window size option state machine: multiple of mss, mtu or
    110  * plain numeric value. Can also be made as plain numeric value which
    111  * is not a multiple of specified value.
    112  */
    113 enum xt_osf_window_size_options {
    114 	OSF_WSS_PLAIN	= 0,
    115 	OSF_WSS_MSS,
    116 	OSF_WSS_MTU,
    117 	OSF_WSS_MODULO,
    118 	OSF_WSS_MAX,
    119 };
    120 
    121 /*
    122  * Add/remove fingerprint from the kernel.
    123  */
    124 enum xt_osf_msg_types {
    125 	OSF_MSG_ADD,
    126 	OSF_MSG_REMOVE,
    127 	OSF_MSG_MAX,
    128 };
    129 
    130 enum xt_osf_attr_type {
    131 	OSF_ATTR_UNSPEC,
    132 	OSF_ATTR_FINGER,
    133 	OSF_ATTR_MAX,
    134 };
    135 
    136 #endif				/* _XT_OSF_H */
    137