xt_osf.h

Go to the documentation of this file.

/*
 * Copyright (c) 2003+ Evgeniy Polyakov <[email protected]>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef _XT_OSF_H
#define _XT_OSF_H

#include <linux/types.h>

#define MAXGENRELEN     32

#define XT_OSF_GENRE        (1<<0)
#define XT_OSF_TTL      (1<<1)
#define XT_OSF_LOG      (1<<2)
#define XT_OSF_INVERT       (1<<3)

#define XT_OSF_LOGLEVEL_ALL 0   /* log all matched fingerprints */
#define XT_OSF_LOGLEVEL_FIRST   1   /* log only the first matced fingerprint */
#define XT_OSF_LOGLEVEL_ALL_KNOWN   2 /* do not log unknown packets */

#define XT_OSF_TTL_TRUE     0   /* True ip and fingerprint TTL comparison */
#define XT_OSF_TTL_LESS     1   /* Check if ip TTL is less than fingerprint one */
#define XT_OSF_TTL_NOCHECK  2   /* Do not compare ip and fingerprint TTL at all */

struct xt_osf_info {
    char            genre[MAXGENRELEN];
    __u32           len;
    __u32           flags;
    __u32           loglevel;
    __u32           ttl;
};

/*
 * Wildcard MSS (kind of).
 * It is used to implement a state machine for the different wildcard values
 * of the MSS and window sizes.
 */
struct xt_osf_wc {
    __u32           wc;
    __u32           val;
};

/*
 * This struct represents IANA options
 * http://www.iana.org/assignments/tcp-parameters
 */
struct xt_osf_opt {
    __u16           kind, length;
    struct xt_osf_wc    wc;
};

struct xt_osf_user_finger {
    struct xt_osf_wc    wss;

    __u8            ttl, df;
    __u16           ss, mss;
    __u16           opt_num;

    char            genre[MAXGENRELEN];
    char            version[MAXGENRELEN];
    char            subtype[MAXGENRELEN];

    /* MAX_IPOPTLEN is maximum if all options are NOPs or EOLs */
    struct xt_osf_opt   opt[MAX_IPOPTLEN];
};

struct xt_osf_nlmsg {
    struct xt_osf_user_finger   f;
    struct iphdr        ip;
    struct tcphdr       tcp;
};

/* Defines for IANA option kinds */

enum iana_options {
    OSFOPT_EOL = 0,     /* End of options */
    OSFOPT_NOP,         /* NOP */
    OSFOPT_MSS,         /* Maximum segment size */
    OSFOPT_WSO,         /* Window scale option */
    OSFOPT_SACKP,       /* SACK permitted */
    OSFOPT_SACK,        /* SACK */
    OSFOPT_ECHO,
    OSFOPT_ECHOREPLY,
    OSFOPT_TS,      /* Timestamp option */
    OSFOPT_POCP,        /* Partial Order Connection Permitted */
    OSFOPT_POSP,        /* Partial Order Service Profile */

    /* Others are not used in the current OSF */
    OSFOPT_EMPTY = 255,
};

/*
 * Initial window size option state machine: multiple of mss, mtu or
 * plain numeric value. Can also be made as plain numeric value which
 * is not a multiple of specified value.
 */
enum xt_osf_window_size_options {
    OSF_WSS_PLAIN   = 0,
    OSF_WSS_MSS,
    OSF_WSS_MTU,
    OSF_WSS_MODULO,
    OSF_WSS_MAX,
};

/*
 * Add/remove fingerprint from the kernel.
 */
enum xt_osf_msg_types {
    OSF_MSG_ADD,
    OSF_MSG_REMOVE,
    OSF_MSG_MAX,
};

enum xt_osf_attr_type {
    OSF_ATTR_UNSPEC,
    OSF_ATTR_FINGER,
    OSF_ATTR_MAX,
};

#endif              /* _XT_OSF_H */