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/*

 *      IP masquerading functionality definitions

 */

#ifndef _IP_MASQ_H

#define _IP_MASQ_H

#include <linux/types.h>

#include <linux/netdevice.h>

#include <linux/skbuff.h>

#include <linux/config.h>

/*

 * This define affects the number of ports that can be handled

 * by each of the protocol helper modules.

 */

#define MAX_MASQ_APP_PORTS 12

/*

 *      Linux ports don't normally get allocated above 32K.

 *      I used an extra 4K port-space

 */

#define PORT_MASQ_BEGIN 61000

#define PORT_MASQ_END   (PORT_MASQ_BEGIN+4096)

/*

 * Default timeouts for masquerade functions The control channels now

 * expire the same as TCP channels (other than being updated by

 * packets on their associated data channels.

 */

#define MASQUERADE_EXPIRE_TCP     15*60*HZ

#define MASQUERADE_EXPIRE_TCP_FIN  2*60*HZ

#define MASQUERADE_EXPIRE_UDP      5*60*HZ

/*

 * ICMP can no longer be modified on the fly using an ioctl - this

 * define is the only way to change the timeouts

 */

#define MASQUERADE_EXPIRE_ICMP      125*HZ

#define IP_AUTOFW_EXPIRE             15*HZ

#define IP_MASQ_F_OUT_SEQ               0x01    /* must do output seq adjust */

#define IP_MASQ_F_IN_SEQ                0x02    /* must do input seq adjust */

#define IP_MASQ_F_NO_DPORT              0x04    /* no dport set yet */

#define IP_MASQ_F_NO_DADDR              0x08    /* no daddr yet */

#define IP_MASQ_F_HASHED                0x10    /* hashed entry */

#define IP_MASQ_F_SAW_RST               0x20    /* tcp rst pkt seen */

#define IP_MASQ_F_SAW_FIN_IN            0x40    /* tcp fin pkt seen incoming */

#define IP_MASQ_F_SAW_FIN_OUT           0x80    /* tcp fin pkt seen outgoing */

#define IP_MASQ_F_SAW_FIN               (IP_MASQ_F_SAW_FIN_IN | \

                                         IP_MASQ_F_SAW_FIN_OUT)

                                                /* tcp fin pkts seen */

#define IP_MASQ_F_CONTROL               0x100   /* this is a control channel */

#define IP_MASQ_F_NO_SPORT              0x200   /* no sport set yet */

#define IP_MASQ_F_FTP_PASV              0x400   /* ftp PASV command just issued */

#define IP_MASQ_F_NO_REPLY              0x800   /* no reply yet from outside */

#define IP_MASQ_F_AFW_PORT             0x1000

#ifdef __KERNEL__

/*

 *      Delta seq. info structure

 *      Each MASQ struct has 2 (output AND input seq. changes).

 */

struct ip_masq_seq {

        __u32           init_seq;       /* Add delta from this seq */

        short           delta;          /* Delta in sequence numbers */

        short           previous_delta; /* Delta in sequence numbers before last resized pkt */

};

/*

 *      MASQ structure allocated for each masqueraded association

 */

struct ip_masq {

        struct ip_masq  *m_link, *s_link; /* hashed link ptrs */

        struct timer_list timer;        /* Expiration timer */

        __u16           protocol;       /* Which protocol are we talking? */

        __u16           sport, dport, mport;    /* src, dst & masq ports */

        __u32           saddr, daddr, maddr;    /* src, dst & masq addresses */

        struct ip_masq_seq out_seq, in_seq;

        struct ip_masq_app *app;        /* bound ip_masq_app object */

        void            *app_data;      /* Application private data */

        unsigned  flags;                /* status flags */

        struct ip_masq  *control;       /* Corresponding control connection */

#ifdef CONFIG_IP_MASQUERADE_IPSEC

        struct ip_masq  *d_link;        /* hashed link ptr */

        __u32           ospi, ispi;     /* outbound and inbound SPI keys for IPSEC */

                                        /* also the icookie for ISAKMP masquerade  */

        short           ocnt;           /* counter of inits sent - limit blocking  */

        short           blocking;       /* if we're blocking another host          */

#endif /* CONFIG_IP_MASQUERADE_IPSEC */

};

/*

 *      timeout values

 */

struct ip_fw_masq {

        int tcp_timeout;

        int tcp_fin_timeout;

        int udp_timeout;

};

extern struct ip_fw_masq *ip_masq_expire;

/*

 *      [0]: UDP free_ports

 *      [1]: TCP free_ports

 *      [2]: ICMP free ids

 */

extern int ip_masq_free_ports[3];

/*

 *      ip_masq initializer (registers symbols and /proc/net entries)

 */

extern int ip_masq_init(void);

/*

 *      functions called from ip layer

 */

extern int ip_fw_masquerade(struct sk_buff **, struct device *);

extern int ip_fw_masq_icmp(struct sk_buff **, struct device *);

extern int ip_fw_demasquerade(struct sk_buff **, struct device *);

/*

 *      ip_masq obj creation/deletion functions.

 */

extern struct ip_masq *ip_masq_new(struct device *dev, int proto, __u32 saddr, __u16 sport, __u32 daddr, __u16 dport, unsigned flags);

extern void ip_masq_set_expire(struct ip_masq *ms, unsigned long tout);

#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW

extern void ip_autofw_expire(unsigned long data);

#endif

/*

 *

 *      IP_MASQ_APP: IP application masquerading definitions

 *

 */

struct ip_masq_app

{

        struct ip_masq_app *next;

        char *name;             /* name of application proxy */

        unsigned type;          /* type = proto<<16 | port (host byte order)*/

        int n_attach;

        int (*masq_init_1)      /* ip_masq initializer */

                (struct ip_masq_app *, struct ip_masq *);

        int (*masq_done_1)      /* ip_masq fin. */

                (struct ip_masq_app *, struct ip_masq *);

        int (*pkt_out)          /* output (masquerading) hook */

                (struct ip_masq_app *, struct ip_masq *, struct sk_buff **, struct device *);

        int (*pkt_in)           /* input (demasq) hook */

                (struct ip_masq_app *, struct ip_masq *, struct sk_buff **, struct device *);

};

/*

 *      ip_masq_app initializer

 */

extern int ip_masq_app_init(void);

/*

 *      ip_masq_app object registration functions (port: host byte order)

 */

extern int register_ip_masq_app(struct ip_masq_app *mapp, unsigned short proto, __u16 port);

extern int unregister_ip_masq_app(struct ip_masq_app *mapp);

/*

 *      get ip_masq_app obj by proto,port(net_byte_order)

 */

extern struct ip_masq_app * ip_masq_app_get(unsigned short proto, __u16 port);

/*

 *      ip_masq TO ip_masq_app (un)binding functions.

 */

extern struct ip_masq_app * ip_masq_bind_app(struct ip_masq *ms);

extern int ip_masq_unbind_app(struct ip_masq *ms);

/*

 *      output and input app. masquerading hooks.

 *

 */

extern int ip_masq_app_pkt_out(struct ip_masq *, struct sk_buff **skb_p, struct device *dev);

extern int ip_masq_app_pkt_in(struct ip_masq *, struct sk_buff **skb_p, struct device *dev);

/*

 *      service routine(s).

 */

extern struct ip_masq * ip_masq_out_get_2(int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port);

extern struct ip_masq * ip_masq_in_get_2(int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port);

/*

 *      /proc/net entry

 */

extern int ip_masq_app_getinfo(char *buffer, char **start, off_t offset, int length, int dummy);

/*

 *      skb_replace function used by "client" modules to replace

 *      a segment of skb.

 */

extern struct sk_buff * ip_masq_skb_replace(struct sk_buff *skb, int pri, char *o_buf, int o_len, char *n_buf, int n_len);

#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW

extern struct ip_autofw * ip_autofw_hosts;

#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */

#endif /* __KERNEL__ */

#endif /* _IP_MASQ_H */