/*-
* Copyright (c) 2010,2013 Lawrence Stewart <lstewart@freebsd.org>
* Copyright (c) 2010 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Lawrence Stewart while studying at the Centre
* for Advanced Internet Architectures, Swinburne University of Technology, made
* possible in part by grants from the FreeBSD Foundation and Cisco University
* Research Program Fund at Community Foundation Silicon Valley.
*
* Portions of this software were developed at the Centre for Advanced
* Internet Architectures, Swinburne University of Technology, Melbourne,
* Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* A KPI modelled on the pfil framework for instantiating helper hook points
* within the kernel for use by Khelp modules. Originally released as part of
* the NewTCP research project at Swinburne University of Technology's Centre
* for Advanced Internet Architectures, Melbourne, Australia, which was made
* possible in part by a grant from the Cisco University Research Program Fund
* at Community Foundation Silicon Valley. More details are available at:
* http://caia.swin.edu.au/urp/newtcp/
*/
#ifndef _SYS_HHOOK_H_
#define _SYS_HHOOK_H_
/* XXXLAS: Is there a way around this? */
#include <sys/lock.h>
#include <sys/rmlock.h>
/* hhook_head flags. */
#define HHH_ISINVNET 0x00000001 /* Is the hook point in a vnet? */
/* Flags common to all register functions. */
#define HHOOK_WAITOK 0x00000001 /* Sleeping allowed. */
#define HHOOK_NOWAIT 0x00000002 /* Sleeping disallowed. */
/* Flags only relevant to hhook_head_register() and hhook_head_is_virtual(). */
#define HHOOK_HEADISINVNET 0x00000100 /* Public proxy for HHH_ISINVNET. */
/* Helper hook types. */
#define HHOOK_TYPE_TCP 1
struct helper;
struct osd;
/* Signature for helper hook functions. */
typedef int (*hhook_func_t)(int32_t hhook_type, int32_t hhook_id, void *udata,
void *ctx_data, void *hdata, struct osd *hosd);
/*
* Information required to add/remove a helper hook function to/from a helper
* hook point.
*/
struct hookinfo {
hhook_func_t hook_func;
struct helper *hook_helper;
void *hook_udata;
int32_t hook_id;
int32_t hook_type;
};
/*
* Ideally this would be private but we need access to the hhh_nhooks member
* variable in order to make the HHOOKS_RUN_IF() macro low impact.
*/
struct hhook_head {
STAILQ_HEAD(hhook_list, hhook) hhh_hooks;
struct rmlock hhh_lock;
uintptr_t hhh_vid;
int32_t hhh_id;
int32_t hhh_nhooks;
int32_t hhh_type;
uint32_t hhh_flags;
volatile uint32_t hhh_refcount;
LIST_ENTRY(hhook_head) hhh_next;
LIST_ENTRY(hhook_head) hhh_vnext;
};
/* Public KPI functions. */
void hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd);
int hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki,
uint32_t flags);
int hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags);
int hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki);
int hhook_remove_hook_lookup(struct hookinfo *hki);
int hhook_head_register(int32_t hhook_type, int32_t hhook_id,
struct hhook_head **hhh, uint32_t flags);
int hhook_head_deregister(struct hhook_head *hhh);
int hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id);
struct hhook_head * hhook_head_get(int32_t hhook_type, int32_t hhook_id);
void hhook_head_release(struct hhook_head *hhh);
uint32_t hhook_head_is_virtualised(struct hhook_head *hhh);
uint32_t hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id);
/*
* A wrapper around hhook_run_hooks() that only calls the function if at least
* one helper hook function is registered for the specified helper hook point.
*/
#define HHOOKS_RUN_IF(hhh, ctx_data, hosd) do { \
if (hhh != NULL && hhh->hhh_nhooks > 0) \
hhook_run_hooks(hhh, ctx_data, hosd); \
} while (0)
/*
* WARNING: This macro should only be used in code paths that execute
* infrequently, otherwise the refcounting overhead would be excessive.
*
* A similar wrapper to HHOOKS_RUN_IF() for situations where the caller prefers
* not to lookup and store the appropriate hhook_head pointer themselves.
*/
#define HHOOKS_RUN_LOOKUP_IF(hhook_type, hhook_id, ctx_data, hosd) do { \
struct hhook_head *_hhh; \
\
_hhh = hhook_head_get(hhook_type, hhook_id); \
if (_hhh != NULL) { \
if (_hhh->hhh_nhooks > 0) \
hhook_run_hooks(_hhh, ctx_data, hosd); \
hhook_head_release(_hhh); \
} \
} while (0)
#endif /* _SYS_HHOOK_H_ */
