include/linux/netfilter/nf_conntrack_tcp.h

   1 #ifndef _NF_CONNTRACK_TCP_H
   2 #define _NF_CONNTRACK_TCP_H
   3 /* TCP tracking. */
   4
   5 /* This is exposed to userspace (ctnetlink) */
   6 enum tcp_conntrack {
   7         TCP_CONNTRACK_NONE,
   8         TCP_CONNTRACK_SYN_SENT,
   9         TCP_CONNTRACK_SYN_RECV,
  10         TCP_CONNTRACK_ESTABLISHED,
  11         TCP_CONNTRACK_FIN_WAIT,
  12         TCP_CONNTRACK_CLOSE_WAIT,
  13         TCP_CONNTRACK_LAST_ACK,
  14         TCP_CONNTRACK_TIME_WAIT,
  15         TCP_CONNTRACK_CLOSE,
  16         TCP_CONNTRACK_LISTEN,
  17         TCP_CONNTRACK_MAX,
  18         TCP_CONNTRACK_IGNORE
  19 };
  20
  21 /* Window scaling is advertised by the sender */
  22 #define IP_CT_TCP_FLAG_WINDOW_SCALE             0x01
  23
  24 /* SACK is permitted by the sender */
  25 #define IP_CT_TCP_FLAG_SACK_PERM                0x02
  26
  27 /* This sender sent FIN first */
  28 #define IP_CT_TCP_FLAG_CLOSE_INIT               0x04
  29
  30 /* Be liberal in window checking */
  31 #define IP_CT_TCP_FLAG_BE_LIBERAL               0x08
  32
  33 struct nf_ct_tcp_flags {
  34         u_int8_t flags;
  35         u_int8_t mask;
  36 };
  37
  38 #ifdef __KERNEL__
  39
  40 struct ip_ct_tcp_state {
  41         u_int32_t       td_end;         /* max of seq + len */
  42         u_int32_t       td_maxend;      /* max of ack + max(win, 1) */
  43         u_int32_t       td_maxwin;      /* max(win) */
  44         u_int8_t        td_scale;       /* window scale factor */
  45         u_int8_t        flags;          /* per direction options */
  46 };
  47
  48 struct ip_ct_tcp
  49 {
  50         struct ip_ct_tcp_state seen[2]; /* connection parameters per direction */
  51         u_int8_t        state;          /* state of the connection (enum tcp_conntrack) */
  52         /* For detecting stale connections */
  53         u_int8_t        last_dir;       /* Direction of the last packet (enum ip_conntrack_dir) */
  54         u_int8_t        retrans;        /* Number of retransmitted packets */
  55         u_int8_t        last_index;     /* Index of the last packet */
  56         u_int32_t       last_seq;       /* Last sequence number seen in dir */
  57         u_int32_t       last_ack;       /* Last sequence number seen in opposite dir */
  58         u_int32_t       last_end;       /* Last seq + len */
  59         u_int16_t       last_win;       /* Last window advertisement seen in dir */
  60 };
  61
  62 #endif /* __KERNEL__ */
  63
  64 #endif /* _NF_CONNTRACK_TCP_H */