/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * This file includes definitions of kernel hook framework components
 */

#ifndef _SYS_HOOK_H
#define _SYS_HOOK_H

#include <sys/queue.h>
#include <sys/netstack.h>

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * Definition exposed to hook provider and consumer
 */

#define HOOK_VERSION    1

typedef uintptr_t hook_data_t;

struct hook_event_int;
typedef struct hook_event_int *hook_event_token_t;
struct hook_int;
typedef struct hook_int *hook_token_t;

typedef int (* hook_func_t)(hook_event_token_t, hook_data_t, void *);

/*
 * A hook_notify_cmd_t is given as an argument to functions called as part of
 * the notify callbacks that have been registered firing.
 */
typedef enum hook_notify_cmd_e {
        HN_NONE = 0,
        HN_REGISTER = 1,
        HN_UNREGISTER = 2
} hook_notify_cmd_t;

/*
 *
 */
typedef enum hook_hint_e {
        HH_NONE = 0,
        HH_FIRST,
        HH_LAST,
        HH_BEFORE,
        HH_AFTER
} hook_hint_t;

/*
 * Hook
 */
typedef struct hook_s {
        int             h_version;
        hook_func_t     h_func;         /* callback func */
        char            *h_name;        /* name of this hook */
        uint_t          h_flags;        /* extra hook properties */
        hook_hint_t     h_hint;         /* What type of hint is hintvalue */
        uintptr_t       h_hintvalue;
        void            *h_arg;         /* value to pass back into the hook */
} hook_t;

#define HOOK_INIT(x, fn, r, a)          \
        do {                                    \
                (x) = hook_alloc(HOOK_VERSION); \
                (x)->h_func = (fn);             \
                (x)->h_name = (r);              \
                (x)->h_flags = 0;               \
                (x)->h_hint = HH_NONE;          \
                (x)->h_hintvalue = 0;           \
                (x)->h_arg = (a);               \
                _NOTE(CONSTCOND)                \
        } while (0)

/*
 * Family
 */
typedef struct hook_family_s {
        int             hf_version;     /* version number */
        char            *hf_name;       /* family name */
} hook_family_t;

#define HOOK_FAMILY_INIT(x, y)                  \
        do {                                    \
                (x)->hf_version = HOOK_VERSION; \
                (x)->hf_name = (y);             \
                _NOTE(CONSTCOND)                \
        } while (0)

/*
 * Event
 */
typedef struct hook_event_s {
        int             he_version;
        char            *he_name;       /* name of this hook list */
        int             he_flags;       /* 1 = multiple entries allowed */
        boolean_t       he_interested;  /* true if callback exist */
} hook_event_t;

#define HOOK_RDONLY     0x1             /* Callbacks must not change data */
                                        /* Multiple callbacks are allowed */

#define HOOK_EVENT_INIT(x, y)                   \
        do {                                    \
                (x)->he_version = HOOK_VERSION; \
                (x)->he_name = (y);             \
                (x)->he_flags = 0;              \
                (x)->he_interested = B_FALSE;   \
                _NOTE(CONSTCOND)                \
        } while (0)

typedef int (* hook_notify_fn_t)(hook_notify_cmd_t, void *, const char *,
    const char *, const char *);

extern  hook_t          *hook_alloc(const int version);
extern  void            hook_free(hook_t *);

#ifdef  __cplusplus
}
#endif

#endif /* _SYS_HOOK_H */