root/include/net/ip_masq.h

/* */

INCLUDED FROM

   1 /*
   2  *      IP masquerading functionality definitions
   3  */
   4 
   5 #ifndef _IP_MASQ_H
   6 #define _IP_MASQ_H
   7 
   8 #include <linux/types.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/skbuff.h>
  11 
  12 /*
  13  *      Linux ports don't normally get allocated above 32K.
  14  *      I used an extra 4K port-space
  15  */
  16  
  17 #define PORT_MASQ_BEGIN 60000
  18 #define PORT_MASQ_END   (PORT_MASQ_BEGIN+4096)
  19 
  20 #define MASQUERADE_EXPIRE_TCP     15*60*HZ
  21 #define MASQUERADE_EXPIRE_TCP_FIN  2*60*HZ
  22 #define MASQUERADE_EXPIRE_UDP      5*60*HZ
  23 
  24 #define IP_MASQ_F_OUT_SEQ               0x01    /* must do output seq adjust */
  25 #define IP_MASQ_F_IN_SEQ                0x02    /* must do input seq adjust */
  26 #define IP_MASQ_F_NO_DPORT              0x04    /* no dport set yet */
  27 #define IP_MASQ_F_NO_DADDR              0x08    /* no daddr yet */
  28 #define IP_MASQ_F_HASHED                0x10    /* hashed entry */
  29 #define IP_MASQ_F_SAW_FIN               0x20    /* tcp fin pkt seen */
  30 
  31 #ifdef __KERNEL__
  32 
  33 /*
  34  *      Delta seq. info structure
  35  *      Each MASQ struct has 2 (output AND input seq. changes).
  36  */
  37 
  38 struct ip_masq_seq {
  39         __u32           init_seq;       /* Add delta from this seq */
  40         short           delta;          /* Delta in sequence numbers */
  41         short           previous_delta; /* Delta in sequence numbers before last resized pkt */
  42 };
  43 
  44 /*
  45  *      MASQ structure allocated for each masqueraded association
  46  */
  47 struct ip_masq {
  48         struct ip_masq  *m_link, *s_link; /* hashed link ptrs */
  49         struct timer_list timer;        /* Expiration timer */
  50         __u16           protocol;       /* Which protocol are we talking? */
  51         __u16           sport, dport, mport;    /* src, dst & masq ports */
  52         __u32           saddr, daddr, maddr;    /* src, dst & masq addresses */
  53         struct ip_masq_seq out_seq, in_seq;
  54         struct ip_masq_app *app;        /* bound ip_masq_app object */
  55         unsigned  flags;                /* status flags */
  56 };
  57 
  58 /*
  59  *      [0]: UDP free_ports
  60  *      [1]: TCP free_ports
  61  */
  62 
  63 extern int ip_masq_free_ports[2];
  64 
  65 /*
  66  *      ip_masq initializer (registers symbols and /proc/net entries)
  67  */
  68 extern int ip_masq_init(void);
  69 
  70 /*
  71  *      functions called from ip layer
  72  */
  73 extern void ip_fw_masquerade(struct sk_buff **, struct device *);
  74 extern int ip_fw_demasquerade(struct sk_buff **, struct device *);
  75 
  76 /*
  77  *      ip_masq obj creation/deletion functions.
  78  */
  79 extern struct ip_masq *ip_masq_new(struct device *dev, int proto, __u32 saddr, __u16 sport, __u32 daddr, __u16 dport, unsigned flags);
  80 extern void ip_masq_set_expire(struct ip_masq *ms, unsigned long tout);
  81 
  82 
  83 /*
  84  *      
  85  *      IP_MASQ_APP: IP application masquerading definitions 
  86  *
  87  */
  88 
  89 struct ip_masq_app
  90 {
  91         struct ip_masq_app *next;
  92         unsigned type;          /* type = proto<<16 | port (host byte order)*/
  93         int n_attach;
  94         int (*masq_init_1)      /* ip_masq initializer */
  95                 (struct ip_masq_app *, struct ip_masq *);
  96         int (*masq_done_1)      /* ip_masq fin. */
  97                 (struct ip_masq_app *, struct ip_masq *);
  98         int (*pkt_out)          /* output (masquerading) hook */
  99                 (struct ip_masq_app *, struct ip_masq *, struct sk_buff **, struct device *);
 100         int (*pkt_in)           /* input (demasq) hook */
 101                 (struct ip_masq_app *, struct ip_masq *, struct sk_buff **, struct device *);
 102 };
 103 
 104 /*
 105  *      ip_masq_app initializer
 106  */
 107 extern int ip_masq_app_init(void);
 108 
 109 /*
 110  *      ip_masq_app object registration functions (port: host byte order)
 111  */
 112 extern int register_ip_masq_app(struct ip_masq_app *mapp, unsigned short proto, __u16 port);
 113 extern int unregister_ip_masq_app(struct ip_masq_app *mapp);
 114 
 115 /*
 116  *      get ip_masq_app obj by proto,port(net_byte_order)
 117  */
 118 extern struct ip_masq_app * ip_masq_app_get(unsigned short proto, __u16 port);
 119 
 120 /*
 121  *      ip_masq TO ip_masq_app (un)binding functions.
 122  */
 123 extern struct ip_masq_app * ip_masq_bind_app(struct ip_masq *ms);
 124 extern int ip_masq_unbind_app(struct ip_masq *ms);
 125 
 126 /*
 127  *      output and input app. masquerading hooks.
 128  *      
 129  */
 130 extern int ip_masq_app_pkt_out(struct ip_masq *, struct sk_buff **skb_p, struct device *dev);
 131 extern int ip_masq_app_pkt_in(struct ip_masq *, struct sk_buff **skb_p, struct device *dev);
 132 
 133 /*
 134  *      /proc/net entry
 135  */
 136 extern int ip_masq_app_getinfo(char *buffer, char **start, off_t offset, int length, int dummy);
 137 
 138 /*
 139  *      skb_replace function used by "client" modules to replace
 140  *      a segment of skb.
 141  */
 142 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);
 143 
 144 #endif /* __KERNEL__ */
 145 
 146 #endif /* _IP_MASQ_H */

/* */