common/sys/hook.h

/*
 * 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 */