libnetfilter_conntrack.h

/*
 * (C) 2005-2008 by Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 */

#ifndef _LIBNETFILTER_CONNTRACK_H_
#define _LIBNETFILTER_CONNTRACK_H_

#include <netinet/in.h>
#include <libnfnetlink/linux_nfnetlink.h>
#include <libnfnetlink/libnfnetlink.h>
#include <libnetfilter_conntrack/linux_nfnetlink_conntrack.h> 

#ifdef __cplusplus
extern "C" {
#endif

enum {
        CONNTRACK = NFNL_SUBSYS_CTNETLINK,
        EXPECT = NFNL_SUBSYS_CTNETLINK_EXP
};

/*
 * Subscribe to all possible conntrack event groups. Use this 
 * flag in case that you want to catch up all the possible 
 * events. Do not use this flag for dumping or any other
 * similar operation.
 */
#define NFCT_ALL_CT_GROUPS (NF_NETLINK_CONNTRACK_NEW|NF_NETLINK_CONNTRACK_UPDATE|NF_NETLINK_CONNTRACK_DESTROY)

struct nfct_handle;

/*
 * [Open|close] a conntrack handler
 */
extern struct nfct_handle *nfct_open(u_int8_t, unsigned);
extern struct nfct_handle *nfct_open_nfnl(struct nfnl_handle *nfnlh,
                                          u_int8_t subsys_id,
                                          unsigned int subscriptions);
extern int nfct_close(struct nfct_handle *cth);

extern int nfct_fd(struct nfct_handle *cth);
extern const struct nfnl_handle *nfct_nfnlh(struct nfct_handle *cth);

/* 
 * NEW libnetfilter_conntrack API 
 */

/* high level API */

#include <sys/types.h>

/* conntrack object */
struct nf_conntrack;

/* conntrack attributes */
enum nf_conntrack_attr {
        ATTR_ORIG_IPV4_SRC = 0,                 /* u32 bits */
        ATTR_IPV4_SRC = ATTR_ORIG_IPV4_SRC,     /* alias */
        ATTR_ORIG_IPV4_DST,                     /* u32 bits */
        ATTR_IPV4_DST = ATTR_ORIG_IPV4_DST,     /* alias */
        ATTR_REPL_IPV4_SRC,                     /* u32 bits */
        ATTR_REPL_IPV4_DST,                     /* u32 bits */
        ATTR_ORIG_IPV6_SRC = 4,                 /* u128 bits */
        ATTR_IPV6_SRC = ATTR_ORIG_IPV6_SRC,     /* alias */
        ATTR_ORIG_IPV6_DST,                     /* u128 bits */
        ATTR_IPV6_DST = ATTR_ORIG_IPV6_DST,     /* alias */
        ATTR_REPL_IPV6_SRC,                     /* u128 bits */
        ATTR_REPL_IPV6_DST,                     /* u128 bits */
        ATTR_ORIG_PORT_SRC = 8,                 /* u16 bits */
        ATTR_PORT_SRC = ATTR_ORIG_PORT_SRC,     /* alias */
        ATTR_ORIG_PORT_DST,                     /* u16 bits */
        ATTR_PORT_DST = ATTR_ORIG_PORT_DST,     /* alias */
        ATTR_REPL_PORT_SRC,                     /* u16 bits */
        ATTR_REPL_PORT_DST,                     /* u16 bits */
        ATTR_ICMP_TYPE = 12,                    /* u8 bits */
        ATTR_ICMP_CODE,                         /* u8 bits */
        ATTR_ICMP_ID,                           /* u16 bits */
        ATTR_ORIG_L3PROTO,                      /* u8 bits */
        ATTR_L3PROTO = ATTR_ORIG_L3PROTO,       /* alias */
        ATTR_REPL_L3PROTO = 16,                 /* u8 bits */
        ATTR_ORIG_L4PROTO,                      /* u8 bits */
        ATTR_L4PROTO = ATTR_ORIG_L4PROTO,       /* alias */
        ATTR_REPL_L4PROTO,                      /* u8 bits */
        ATTR_TCP_STATE,                         /* u8 bits */
        ATTR_SNAT_IPV4 = 20,                    /* u32 bits */
        ATTR_DNAT_IPV4,                         /* u32 bits */
        ATTR_SNAT_PORT,                         /* u16 bits */
        ATTR_DNAT_PORT,                         /* u16 bits */
        ATTR_TIMEOUT = 24,                      /* u32 bits */
        ATTR_MARK,                              /* u32 bits */
        ATTR_ORIG_COUNTER_PACKETS,              /* u64 bits */
        ATTR_REPL_COUNTER_PACKETS,              /* u64 bits */
        ATTR_ORIG_COUNTER_BYTES = 28,           /* u64 bits */
        ATTR_REPL_COUNTER_BYTES,                /* u64 bits */
        ATTR_USE,                               /* u32 bits */
        ATTR_ID,                                /* u32 bits */
        ATTR_STATUS = 32,                       /* u32 bits  */
        ATTR_TCP_FLAGS_ORIG,                    /* u8 bits */
        ATTR_TCP_FLAGS_REPL,                    /* u8 bits */
        ATTR_TCP_MASK_ORIG,                     /* u8 bits */
        ATTR_TCP_MASK_REPL = 36,                /* u8 bits */
        ATTR_MASTER_IPV4_SRC,                   /* u32 bits */
        ATTR_MASTER_IPV4_DST,                   /* u32 bits */
        ATTR_MASTER_IPV6_SRC,                   /* u128 bits */
        ATTR_MASTER_IPV6_DST = 40,              /* u128 bits */
        ATTR_MASTER_PORT_SRC,                   /* u16 bits */
        ATTR_MASTER_PORT_DST,                   /* u16 bits */
        ATTR_MASTER_L3PROTO,                    /* u8 bits */
        ATTR_MASTER_L4PROTO = 44,               /* u8 bits */
        ATTR_SECMARK,                           /* u32 bits */
        ATTR_ORIG_NAT_SEQ_CORRECTION_POS,       /* u32 bits */
        ATTR_ORIG_NAT_SEQ_OFFSET_BEFORE,        /* u32 bits */
        ATTR_ORIG_NAT_SEQ_OFFSET_AFTER = 48,    /* u32 bits */
        ATTR_REPL_NAT_SEQ_CORRECTION_POS,       /* u32 bits */
        ATTR_REPL_NAT_SEQ_OFFSET_BEFORE,        /* u32 bits */
        ATTR_REPL_NAT_SEQ_OFFSET_AFTER,         /* u32 bits */
        ATTR_SCTP_STATE = 52,                   /* u8 bits */
        ATTR_SCTP_VTAG_ORIG,                    /* u32 bits */
        ATTR_SCTP_VTAG_REPL,                    /* u32 bits */
        ATTR_HELPER_NAME,                       /* string (30 bytes max) */
        ATTR_DCCP_STATE = 56,                   /* u8 bits */
        ATTR_DCCP_ROLE,                         /* u8 bits */
        ATTR_DCCP_HANDSHAKE_SEQ,                /* u64 bits */
        ATTR_TCP_WSCALE_ORIG,                   /* u8 bits */
        ATTR_TCP_WSCALE_REPL = 60,              /* u8 bits */
        ATTR_ZONE,                              /* u16 bits */
        ATTR_SECCTX,                            /* string */
        ATTR_MAX
};

/* conntrack attribute groups */
enum nf_conntrack_attr_grp {
        ATTR_GRP_ORIG_IPV4 = 0,                 /* struct nfct_attr_grp_ipv4 */
        ATTR_GRP_REPL_IPV4,                     /* struct nfct_attr_grp_ipv4 */
        ATTR_GRP_ORIG_IPV6,                     /* struct nfct_attr_grp_ipv6 */
        ATTR_GRP_REPL_IPV6,                     /* struct nfct_attr_grp_ipv6 */
        ATTR_GRP_ORIG_PORT = 4,                 /* struct nfct_attr_grp_port */
        ATTR_GRP_REPL_PORT,                     /* struct nfct_attr_grp_port */
        ATTR_GRP_ICMP,                          /* struct nfct_attr_grp_icmp */
        ATTR_GRP_MASTER_IPV4,                   /* struct nfct_attr_grp_ipv4 */
        ATTR_GRP_MASTER_IPV6 = 8,               /* struct nfct_attr_grp_ipv6 */
        ATTR_GRP_MASTER_PORT,                   /* struct nfct_attr_grp_port */
        ATTR_GRP_ORIG_COUNTERS,                 /* struct nfct_attr_grp_ctrs */
        ATTR_GRP_REPL_COUNTERS,                 /* struct nfct_attr_grp_ctrs */
        ATTR_GRP_MAX
};

struct nfct_attr_grp_ipv4 {
        u_int32_t src, dst;
};

struct nfct_attr_grp_ipv6 {
        u_int32_t src[4], dst[4];
};

struct nfct_attr_grp_port {
        u_int16_t sport, dport;
};

struct nfct_attr_grp_icmp {
        u_int16_t id;
        u_int8_t code, type;
};

struct nfct_attr_grp_ctrs {
        u_int64_t packets;
        u_int64_t bytes;
};

/* message type */
enum nf_conntrack_msg_type {
        NFCT_T_UNKNOWN = 0,

        NFCT_T_NEW_BIT = 0,
        NFCT_T_NEW = (1 << NFCT_T_NEW_BIT),

        NFCT_T_UPDATE_BIT = 1,
        NFCT_T_UPDATE = (1 << NFCT_T_UPDATE_BIT),

        NFCT_T_DESTROY_BIT = 2,
        NFCT_T_DESTROY = (1 << NFCT_T_DESTROY_BIT),

        NFCT_T_ALL = NFCT_T_NEW | NFCT_T_UPDATE | NFCT_T_DESTROY,

        NFCT_T_ERROR_BIT = 31,
        NFCT_T_ERROR = (1 << NFCT_T_ERROR_BIT),
};

/* constructor / destructor */
extern struct nf_conntrack *nfct_new(void);
extern void nfct_destroy(struct nf_conntrack *ct);

/* clone */
struct nf_conntrack *nfct_clone(const struct nf_conntrack *ct);

/* object size */
extern size_t nfct_sizeof(const struct nf_conntrack *ct);

/* maximum object size */
extern size_t nfct_maxsize(void);

/* set option */
enum {
        NFCT_SOPT_UNDO_SNAT,
        NFCT_SOPT_UNDO_DNAT,
        NFCT_SOPT_UNDO_SPAT,
        NFCT_SOPT_UNDO_DPAT,
        NFCT_SOPT_SETUP_ORIGINAL,
        NFCT_SOPT_SETUP_REPLY,
        __NFCT_SOPT_MAX,
};
#define NFCT_SOPT_MAX (__NFCT_SOPT_MAX - 1)

/* get option */
enum {
        NFCT_GOPT_IS_SNAT,
        NFCT_GOPT_IS_DNAT,
        NFCT_GOPT_IS_SPAT,
        NFCT_GOPT_IS_DPAT,
        __NFCT_GOPT_MAX,
};
#define NFCT_GOPT_MAX (__NFCT_GOPT_MAX - 1)

extern int nfct_setobjopt(struct nf_conntrack *ct, unsigned int option);
extern int nfct_getobjopt(const struct nf_conntrack *ct, unsigned int option);

/* register / unregister callback */

extern int nfct_callback_register(struct nfct_handle *h,
                                  enum nf_conntrack_msg_type type,
                                  int (*cb)(enum nf_conntrack_msg_type type,
                                            struct nf_conntrack *ct,
                                            void *data),
                                  void *data);

extern void nfct_callback_unregister(struct nfct_handle *h);

/* register / unregister callback: extended version including netlink header */

extern int nfct_callback_register2(struct nfct_handle *h,
                                   enum nf_conntrack_msg_type type,
                                   int (*cb)(const struct nlmsghdr *nlh,
                                             enum nf_conntrack_msg_type type,
                                             struct nf_conntrack *ct,
                                             void *data),
                                   void *data);

extern void nfct_callback_unregister2(struct nfct_handle *h);

/* callback verdict */
enum {
        NFCT_CB_FAILURE = -1,   /* failure */
        NFCT_CB_STOP = 0,       /* stop the query */
        NFCT_CB_CONTINUE = 1,   /* keep iterating through data */
        NFCT_CB_STOLEN = 2,     /* like continue, but ct is not freed */
};

/* setter */
extern void nfct_set_attr(struct nf_conntrack *ct,
                          const enum nf_conntrack_attr type,
                          const void *value);

extern void nfct_set_attr_u8(struct nf_conntrack *ct,
                             const enum nf_conntrack_attr type,
                             u_int8_t value);

extern void nfct_set_attr_u16(struct nf_conntrack *ct,
                              const enum nf_conntrack_attr type,
                              u_int16_t value);

extern void nfct_set_attr_u32(struct nf_conntrack *ct,
                              const enum nf_conntrack_attr type,
                              u_int32_t value);

extern void nfct_set_attr_u64(struct nf_conntrack *ct,
                              const enum nf_conntrack_attr type,
                              u_int64_t value);

/* getter */
extern const void *nfct_get_attr(const struct nf_conntrack *ct,
                                 const enum nf_conntrack_attr type);

extern u_int8_t nfct_get_attr_u8(const struct nf_conntrack *ct,
                                 const enum nf_conntrack_attr type);

extern u_int16_t nfct_get_attr_u16(const struct nf_conntrack *ct,
                                   const enum nf_conntrack_attr type);

extern u_int32_t nfct_get_attr_u32(const struct nf_conntrack *ct,
                                   const enum nf_conntrack_attr type);

extern u_int64_t nfct_get_attr_u64(const struct nf_conntrack *ct,
                                   const enum nf_conntrack_attr type);

/* checker */
extern int nfct_attr_is_set(const struct nf_conntrack *ct,
                            const enum nf_conntrack_attr type);

extern int nfct_attr_is_set_array(const struct nf_conntrack *ct,
                                  const enum nf_conntrack_attr *type_array,
                                  int size);

/* unsetter */
extern int nfct_attr_unset(struct nf_conntrack *ct,
                           const enum nf_conntrack_attr type);

/* group setter */
extern void nfct_set_attr_grp(struct nf_conntrack *ct,
                              const enum nf_conntrack_attr_grp type,
                              const void *value);
/* group getter */
extern int nfct_get_attr_grp(const struct nf_conntrack *ct,
                             const enum nf_conntrack_attr_grp type,
                             void *data);

/* group checker */
extern int nfct_attr_grp_is_set(const struct nf_conntrack *ct,
                                const enum nf_conntrack_attr_grp type);

/* unsetter */
extern int nfct_attr_grp_unset(struct nf_conntrack *ct,
                               const enum nf_conntrack_attr_grp type);

/* print */

/* output type */
enum {
        NFCT_O_PLAIN,
        NFCT_O_DEFAULT = NFCT_O_PLAIN,
        NFCT_O_XML,
        NFCT_O_MAX
};

/* output flags */
enum {
        NFCT_OF_SHOW_LAYER3_BIT = 0,
        NFCT_OF_SHOW_LAYER3 = (1 << NFCT_OF_SHOW_LAYER3_BIT),

        NFCT_OF_TIME_BIT = 1,
        NFCT_OF_TIME = (1 << NFCT_OF_TIME_BIT),

        NFCT_OF_ID_BIT = 2,
        NFCT_OF_ID = (1 << NFCT_OF_ID_BIT),
};

extern int nfct_snprintf(char *buf, 
                         unsigned int size,
                         const struct nf_conntrack *ct,
                         const unsigned int msg_type,
                         const unsigned int out_type,
                         const unsigned int out_flags);

/* comparison */
extern int nfct_compare(const struct nf_conntrack *ct1,
                        const struct nf_conntrack *ct2);

enum {
        NFCT_CMP_ALL = 0,
        NFCT_CMP_ORIG = (1 << 0),
        NFCT_CMP_REPL = (1 << 1),
        NFCT_CMP_TIMEOUT_EQ = (1 << 2),
        NFCT_CMP_TIMEOUT_GT = (1 << 3),
        NFCT_CMP_TIMEOUT_GE = (NFCT_CMP_TIMEOUT_EQ | NFCT_CMP_TIMEOUT_GT),
        NFCT_CMP_TIMEOUT_LT = (1 << 4),
        NFCT_CMP_TIMEOUT_LE = (NFCT_CMP_TIMEOUT_EQ | NFCT_CMP_TIMEOUT_LT),
        NFCT_CMP_MASK = (1 << 5),
        NFCT_CMP_STRICT = (1 << 6),
};

extern int nfct_cmp(const struct nf_conntrack *ct1,
                    const struct nf_conntrack *ct2,
                    unsigned int flags);


/* query */
enum nf_conntrack_query {
        NFCT_Q_CREATE,
        NFCT_Q_UPDATE,
        NFCT_Q_DESTROY,
        NFCT_Q_GET,
        NFCT_Q_FLUSH,
        NFCT_Q_DUMP,
        NFCT_Q_DUMP_RESET,
        NFCT_Q_CREATE_UPDATE,
};

extern int nfct_query(struct nfct_handle *h,
                      const enum nf_conntrack_query query,
                      const void *data);

extern int nfct_send(struct nfct_handle *h,
                     const enum nf_conntrack_query query,
                     const void *data);

extern int nfct_catch(struct nfct_handle *h);

/* copy */
enum {
        NFCT_CP_ALL = 0,
        NFCT_CP_ORIG = (1 << 0),
        NFCT_CP_REPL = (1 << 1),
        NFCT_CP_META = (1 << 2),
};

extern void nfct_copy(struct nf_conntrack *dest,
                      const struct nf_conntrack *source,
                      unsigned int flags);

extern void nfct_copy_attr(struct nf_conntrack *ct1,
                           const struct nf_conntrack *ct2,
                           const enum nf_conntrack_attr type);

/* filter */

struct nfct_filter;

extern struct nfct_filter *nfct_filter_create(void);
extern void nfct_filter_destroy(struct nfct_filter *filter);

struct nfct_filter_proto {
        u_int16_t proto;
        u_int16_t state;
};
struct nfct_filter_ipv4 {
        u_int32_t addr;
        u_int32_t mask;
};
struct nfct_filter_ipv6 {
        u_int32_t addr[4];
        u_int32_t mask[4];
};

enum nfct_filter_attr {
        NFCT_FILTER_L4PROTO = 0,        /* u_int32_t */
        NFCT_FILTER_L4PROTO_STATE,      /* struct nfct_filter_proto */
        NFCT_FILTER_SRC_IPV4,           /* struct nfct_filter_ipv4 */
        NFCT_FILTER_DST_IPV4,           /* struct nfct_filter_ipv4 */
        NFCT_FILTER_SRC_IPV6,           /* struct nfct_filter_ipv6 */
        NFCT_FILTER_DST_IPV6,           /* struct nfct_filter_ipv6 */
        NFCT_FILTER_MAX
};

extern void nfct_filter_add_attr(struct nfct_filter *filter,
                                 const enum nfct_filter_attr attr,
                                 const void *value);

extern void nfct_filter_add_attr_u32(struct nfct_filter *filter,
                                     const enum nfct_filter_attr attr,
                                     const u_int32_t value);

enum nfct_filter_logic {
        NFCT_FILTER_LOGIC_POSITIVE,
        NFCT_FILTER_LOGIC_NEGATIVE,
        NFCT_FILTER_LOGIC_MAX
};

extern int nfct_filter_set_logic(struct nfct_filter *filter,
                                 const enum nfct_filter_attr attr,
                                 const enum nfct_filter_logic logic);

extern int nfct_filter_attach(int fd, struct nfct_filter *filter);
extern int nfct_filter_detach(int fd);

/* low level API: netlink functions */

extern int nfct_build_conntrack(struct nfnl_subsys_handle *ssh,
                                void *req,
                                size_t size,
                                u_int16_t type,
                                u_int16_t flags,
                                const struct nf_conntrack *ct);

extern int nfct_parse_conntrack(enum nf_conntrack_msg_type msg,
                                const struct nlmsghdr *nlh, 
                                struct nf_conntrack *ct);

extern int nfct_build_query(struct nfnl_subsys_handle *ssh,
                            const enum nf_conntrack_query query,
                            const void *data,
                            void *req,
                            unsigned int size);

/*
 * NEW expectation API
 */

/* expectation object */
struct nf_expect;

/* expect attributes */
enum nf_expect_attr {
        ATTR_EXP_MASTER = 0,    /* pointer to conntrack object */
        ATTR_EXP_EXPECTED,      /* pointer to conntrack object */
        ATTR_EXP_MASK,          /* pointer to conntrack object */
        ATTR_EXP_TIMEOUT,       /* u32 bits */
        ATTR_EXP_ZONE,          /* u16 bits */
        ATTR_EXP_FLAGS,         /* u32 bits */
        ATTR_EXP_MAX
};

/* constructor / destructor */
extern struct nf_expect *nfexp_new(void);
extern void nfexp_destroy(struct nf_expect *exp);

/* clone */
extern struct nf_expect *nfexp_clone(const struct nf_expect *exp);

/* object size */
extern size_t nfexp_sizeof(const struct nf_expect *exp);

/* maximum object size */
extern size_t nfexp_maxsize(void);

/* register / unregister callback */

extern int nfexp_callback_register(struct nfct_handle *h,
                                   enum nf_conntrack_msg_type type,
                                   int (*cb)(enum nf_conntrack_msg_type type,
                                             struct nf_expect *exp,
                                             void *data),
                                   void *data);

extern void nfexp_callback_unregister(struct nfct_handle *h);

/* register / unregister callback: extended version including netlink header */
extern int nfexp_callback_register2(struct nfct_handle *h,
                                    enum nf_conntrack_msg_type type,
                                    int (*cb)(const struct nlmsghdr *nlh,
                                              enum nf_conntrack_msg_type type,
                                              struct nf_expect *exp,
                                              void *data),
                                    void *data);

extern void nfexp_callback_unregister2(struct nfct_handle *h);

/* setter */
extern void nfexp_set_attr(struct nf_expect *exp,
                           const enum nf_expect_attr type,
                           const void *value);

extern void nfexp_set_attr_u8(struct nf_expect *exp,
                              const enum nf_expect_attr type,
                              u_int8_t value);

extern void nfexp_set_attr_u16(struct nf_expect *exp,
                               const enum nf_expect_attr type,
                               u_int16_t value);

extern void nfexp_set_attr_u32(struct nf_expect *exp,
                               const enum nf_expect_attr type,
                               u_int32_t value);

/* getter */
extern const void *nfexp_get_attr(const struct nf_expect *exp,
                                  const enum nf_expect_attr type);

extern u_int8_t nfexp_get_attr_u8(const struct nf_expect *exp,
                                  const enum nf_expect_attr type);

extern u_int16_t nfexp_get_attr_u16(const struct nf_expect *exp,
                                    const enum nf_expect_attr type);

extern u_int32_t nfexp_get_attr_u32(const struct nf_expect *exp,
                                    const enum nf_expect_attr type);

/* checker */
extern int nfexp_attr_is_set(const struct nf_expect *exp,
                             const enum nf_expect_attr type);

/* unsetter */
extern int nfexp_attr_unset(struct nf_expect *exp,
                            const enum nf_expect_attr type);

/* query */
extern int nfexp_query(struct nfct_handle *h,
                       const enum nf_conntrack_query qt,
                       const void *data);

/* print */
extern int nfexp_snprintf(char *buf, 
                          unsigned int size,
                          const struct nf_expect *exp,
                          const unsigned int msg_type,
                          const unsigned int out_type,
                          const unsigned int out_flags);

extern int nfexp_catch(struct nfct_handle *h);

/* low level API */
extern int nfexp_build_expect(struct nfnl_subsys_handle *ssh,
                              void *req,
                              size_t size,
                              u_int16_t type,
                              u_int16_t flags,
                              const struct nf_expect *exp);

extern int nfexp_parse_expect(enum nf_conntrack_msg_type type,
                              const struct nlmsghdr *nlh,
                              struct nf_expect *exp);

extern int nfexp_build_query(struct nfnl_subsys_handle *ssh,
                             const enum nf_conntrack_query qt,
                             const void *data,
                             void *buffer,
                             unsigned int size);

/* Bitset representing status of connection. Taken from ip_conntrack.h
 * 
 * Note: For backward compatibility this shouldn't ever change
 *       in kernel space.
 */
enum ip_conntrack_status {
        /* It's an expected connection: bit 0 set.  This bit never changed */
        IPS_EXPECTED_BIT = 0,
        IPS_EXPECTED = (1 << IPS_EXPECTED_BIT),

        /* We've seen packets both ways: bit 1 set.  Can be set, not unset. */
        IPS_SEEN_REPLY_BIT = 1,
        IPS_SEEN_REPLY = (1 << IPS_SEEN_REPLY_BIT),

        /* Conntrack should never be early-expired. */
        IPS_ASSURED_BIT = 2,
        IPS_ASSURED = (1 << IPS_ASSURED_BIT),

        /* Connection is confirmed: originating packet has left box */
        IPS_CONFIRMED_BIT = 3,
        IPS_CONFIRMED = (1 << IPS_CONFIRMED_BIT),

        /* Connection needs src nat in orig dir.  This bit never changed. */
        IPS_SRC_NAT_BIT = 4,
        IPS_SRC_NAT = (1 << IPS_SRC_NAT_BIT),

        /* Connection needs dst nat in orig dir.  This bit never changed. */
        IPS_DST_NAT_BIT = 5,
        IPS_DST_NAT = (1 << IPS_DST_NAT_BIT),

        /* Both together. */
        IPS_NAT_MASK = (IPS_DST_NAT | IPS_SRC_NAT),

        /* Connection needs TCP sequence adjusted. */
        IPS_SEQ_ADJUST_BIT = 6,
        IPS_SEQ_ADJUST = (1 << IPS_SEQ_ADJUST_BIT),

        /* NAT initialization bits. */
        IPS_SRC_NAT_DONE_BIT = 7,
        IPS_SRC_NAT_DONE = (1 << IPS_SRC_NAT_DONE_BIT),

        IPS_DST_NAT_DONE_BIT = 8,
        IPS_DST_NAT_DONE = (1 << IPS_DST_NAT_DONE_BIT),

        /* Both together */
        IPS_NAT_DONE_MASK = (IPS_DST_NAT_DONE | IPS_SRC_NAT_DONE),

        /* Connection is dying (removed from lists), can not be unset. */
        IPS_DYING_BIT = 9,
        IPS_DYING = (1 << IPS_DYING_BIT),

    /* Connection has fixed timeout. */
        IPS_FIXED_TIMEOUT_BIT = 10,
        IPS_FIXED_TIMEOUT = (1 << IPS_FIXED_TIMEOUT_BIT),
};

/* expectation flags */
#define NF_CT_EXPECT_PERMANENT          0x1
#define NF_CT_EXPECT_INACTIVE           0x2
#define NF_CT_EXPECT_USERSPACE          0x4

/*
 * TCP flags
 */

/* Window scaling is advertised by the sender */
#define IP_CT_TCP_FLAG_WINDOW_SCALE             0x01

/* SACK is permitted by the sender */
#define IP_CT_TCP_FLAG_SACK_PERM                0x02

/* This sender sent FIN first */
#define IP_CT_TCP_FLAG_CLOSE_INIT               0x04

/* Be liberal in window checking */
#define IP_CT_TCP_FLAG_BE_LIBERAL               0x08

/* WARNING: do not use these constants in new applications, we keep them here
 * to avoid breaking backward compatibility. */
#define NFCT_DIR_ORIGINAL 0
#define NFCT_DIR_REPLY 1
#define NFCT_DIR_MAX NFCT_DIR_REPLY+1

#ifdef __cplusplus
}
#endif

#endif  /* _LIBNETFILTER_CONNTRACK_H_ */