root/include/net/ip_masq.h

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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  *      timeout values
  60  */
  61 
  62 struct ip_fw_masq {
  63         int tcp_timeout;
  64         int tcp_fin_timeout;
  65         int udp_timeout;
  66 };
  67 
  68 extern struct ip_fw_masq *ip_masq_expire;
  69 
  70 /*
  71  *      [0]: UDP free_ports
  72  *      [1]: TCP free_ports
  73  */
  74 
  75 extern int ip_masq_free_ports[2];
  76 
  77 /*
  78  *      ip_masq initializer (registers symbols and /proc/net entries)
  79  */
  80 extern int ip_masq_init(void);
  81 
  82 /*
  83  *      functions called from ip layer
  84  */
  85 extern void ip_fw_masquerade(struct sk_buff **, struct device *);
  86 extern int ip_fw_demasquerade(struct sk_buff **, struct device *);
  87 
  88 /*
  89  *      ip_masq obj creation/deletion functions.
  90  */
  91 extern struct ip_masq *ip_masq_new(struct device *dev, int proto, __u32 saddr, __u16 sport, __u32 daddr, __u16 dport, unsigned flags);
  92 extern void ip_masq_set_expire(struct ip_masq *ms, unsigned long tout);
  93 
  94 
  95 /*
  96  *      
  97  *      IP_MASQ_APP: IP application masquerading definitions 
  98  *
  99  */
 100 
 101 struct ip_masq_app
 102 {
 103         struct ip_masq_app *next;
 104         unsigned type;          /* type = proto<<16 | port (host byte order)*/
 105         int n_attach;
 106         int (*masq_init_1)      /* ip_masq initializer */
 107                 (struct ip_masq_app *, struct ip_masq *);
 108         int (*masq_done_1)      /* ip_masq fin. */
 109                 (struct ip_masq_app *, struct ip_masq *);
 110         int (*pkt_out)          /* output (masquerading) hook */
 111                 (struct ip_masq_app *, struct ip_masq *, struct sk_buff **, struct device *);
 112         int (*pkt_in)           /* input (demasq) hook */
 113                 (struct ip_masq_app *, struct ip_masq *, struct sk_buff **, struct device *);
 114 };
 115 
 116 /*
 117  *      ip_masq_app initializer
 118  */
 119 extern int ip_masq_app_init(void);
 120 
 121 /*
 122  *      ip_masq_app object registration functions (port: host byte order)
 123  */
 124 extern int register_ip_masq_app(struct ip_masq_app *mapp, unsigned short proto, __u16 port);
 125 extern int unregister_ip_masq_app(struct ip_masq_app *mapp);
 126 
 127 /*
 128  *      get ip_masq_app obj by proto,port(net_byte_order)
 129  */
 130 extern struct ip_masq_app * ip_masq_app_get(unsigned short proto, __u16 port);
 131 
 132 /*
 133  *      ip_masq TO ip_masq_app (un)binding functions.
 134  */
 135 extern struct ip_masq_app * ip_masq_bind_app(struct ip_masq *ms);
 136 extern int ip_masq_unbind_app(struct ip_masq *ms);
 137 
 138 /*
 139  *      output and input app. masquerading hooks.
 140  *      
 141  */
 142 extern int ip_masq_app_pkt_out(struct ip_masq *, struct sk_buff **skb_p, struct device *dev);
 143 extern int ip_masq_app_pkt_in(struct ip_masq *, struct sk_buff **skb_p, struct device *dev);
 144 
 145 /*
 146  *      /proc/net entry
 147  */
 148 extern int ip_masq_app_getinfo(char *buffer, char **start, off_t offset, int length, int dummy);
 149 
 150 /*
 151  *      skb_replace function used by "client" modules to replace
 152  *      a segment of skb.
 153  */
 154 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);
 155 
 156 #endif /* __KERNEL__ */
 157 
 158 #endif /* _IP_MASQ_H */

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