601d4c7543
type and id, as compared to virtualised hook points which are now uniquely identified by type, id and a vid (which for vimage is the pointer to the vnet that the hhook resides in). All hhook_head structs for both virtualised and non-virtualised hook points coexist in hhook_head_list, and a separate list is maintained for hhook points within each vnet to simplify some vimage-related housekeeping. Reviewed by: scottl MFC after: 1 week
456 lines
11 KiB
C
456 lines
11 KiB
C
/*-
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* Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
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* Copyright (c) 2010 The FreeBSD Foundation
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* All rights reserved.
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*
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* This software was developed by Lawrence Stewart while studying at the Centre
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* for Advanced Internet Architectures, Swinburne University of Technology,
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* made possible in part by grants from the FreeBSD Foundation and Cisco
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* University Research Program Fund at Community Foundation Silicon Valley.
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*
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* Portions of this software were developed at the Centre for Advanced
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* Internet Architectures, Swinburne University of Technology, Melbourne,
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* Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/hhook.h>
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#include <sys/khelp.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/module_khelp.h>
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#include <sys/osd.h>
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#include <sys/queue.h>
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#include <sys/refcount.h>
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#include <sys/systm.h>
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#include <net/vnet.h>
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struct hhook {
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hhook_func_t hhk_func;
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struct helper *hhk_helper;
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void *hhk_udata;
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STAILQ_ENTRY(hhook) hhk_next;
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};
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static MALLOC_DEFINE(M_HHOOK, "hhook", "Helper hooks are linked off hhook_head lists");
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LIST_HEAD(hhookheadhead, hhook_head);
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struct hhookheadhead hhook_head_list;
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VNET_DEFINE(struct hhookheadhead, hhook_vhead_list);
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#define V_hhook_vhead_list VNET(hhook_vhead_list)
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static struct mtx hhook_head_list_lock;
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MTX_SYSINIT(hhookheadlistlock, &hhook_head_list_lock, "hhook_head list lock",
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MTX_DEF);
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/* Private function prototypes. */
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static void hhook_head_destroy(struct hhook_head *hhh);
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#define HHHLIST_LOCK() mtx_lock(&hhook_head_list_lock)
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#define HHHLIST_UNLOCK() mtx_unlock(&hhook_head_list_lock)
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#define HHHLIST_LOCK_ASSERT() mtx_assert(&hhook_head_list_lock, MA_OWNED)
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#define HHH_LOCK_INIT(hhh) rm_init(&(hhh)->hhh_lock, "hhook_head rm lock")
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#define HHH_LOCK_DESTROY(hhh) rm_destroy(&(hhh)->hhh_lock)
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#define HHH_WLOCK(hhh) rm_wlock(&(hhh)->hhh_lock)
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#define HHH_WUNLOCK(hhh) rm_wunlock(&(hhh)->hhh_lock)
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#define HHH_RLOCK(hhh, rmpt) rm_rlock(&(hhh)->hhh_lock, (rmpt))
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#define HHH_RUNLOCK(hhh, rmpt) rm_runlock(&(hhh)->hhh_lock, (rmpt))
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/*
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* Run all helper hook functions for a given hook point.
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*/
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void
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hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd)
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{
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struct hhook *hhk;
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void *hdata;
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struct rm_priotracker rmpt;
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KASSERT(hhh->hhh_refcount > 0, ("hhook_head %p refcount is 0", hhh));
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HHH_RLOCK(hhh, &rmpt);
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STAILQ_FOREACH(hhk, &hhh->hhh_hooks, hhk_next) {
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if (hhk->hhk_helper->h_flags & HELPER_NEEDS_OSD) {
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hdata = osd_get(OSD_KHELP, hosd, hhk->hhk_helper->h_id);
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if (hdata == NULL)
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continue;
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} else
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hdata = NULL;
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/*
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* XXXLAS: We currently ignore the int returned by the hook,
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* but will likely want to handle it in future to allow hhook to
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* be used like pfil and effect changes at the hhook calling
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* site e.g. we could define a new hook type of HHOOK_TYPE_PFIL
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* and standardise what particular return values mean and set
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* the context data to pass exactly the same information as pfil
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* hooks currently receive, thus replicating pfil with hhook.
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*/
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hhk->hhk_func(hhh->hhh_type, hhh->hhh_id, hhk->hhk_udata,
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ctx_data, hdata, hosd);
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}
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HHH_RUNLOCK(hhh, &rmpt);
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}
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/*
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* Register a new helper hook function with a helper hook point.
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*/
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int
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hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki, uint32_t flags)
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{
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struct hhook *hhk, *tmp;
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int error;
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error = 0;
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if (hhh == NULL)
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return (ENOENT);
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hhk = malloc(sizeof(struct hhook), M_HHOOK,
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M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT));
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if (hhk == NULL)
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return (ENOMEM);
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hhk->hhk_helper = hki->hook_helper;
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hhk->hhk_func = hki->hook_func;
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hhk->hhk_udata = hki->hook_udata;
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HHH_WLOCK(hhh);
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STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) {
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if (tmp->hhk_func == hki->hook_func &&
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tmp->hhk_udata == hki->hook_udata) {
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/* The helper hook function is already registered. */
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error = EEXIST;
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break;
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}
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}
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if (!error) {
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STAILQ_INSERT_TAIL(&hhh->hhh_hooks, hhk, hhk_next);
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hhh->hhh_nhooks++;
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} else
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free(hhk, M_HHOOK);
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HHH_WUNLOCK(hhh);
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return (error);
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}
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/*
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* Lookup a helper hook point and register a new helper hook function with it.
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*/
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int
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hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags)
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{
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struct hhook_head *hhh;
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int error;
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hhh = hhook_head_get(hki->hook_type, hki->hook_id);
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if (hhh == NULL)
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return (ENOENT);
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error = hhook_add_hook(hhh, hki, flags);
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hhook_head_release(hhh);
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return (error);
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}
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/*
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* Remove a helper hook function from a helper hook point.
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*/
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int
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hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki)
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{
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struct hhook *tmp;
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if (hhh == NULL)
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return (ENOENT);
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HHH_WLOCK(hhh);
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STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) {
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if (tmp->hhk_func == hki->hook_func &&
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tmp->hhk_udata == hki->hook_udata) {
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STAILQ_REMOVE(&hhh->hhh_hooks, tmp, hhook, hhk_next);
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free(tmp, M_HHOOK);
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hhh->hhh_nhooks--;
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break;
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}
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}
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HHH_WUNLOCK(hhh);
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return (0);
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}
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/*
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* Lookup a helper hook point and remove a helper hook function from it.
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*/
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int
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hhook_remove_hook_lookup(struct hookinfo *hki)
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{
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struct hhook_head *hhh;
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hhh = hhook_head_get(hki->hook_type, hki->hook_id);
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if (hhh == NULL)
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return (ENOENT);
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hhook_remove_hook(hhh, hki);
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hhook_head_release(hhh);
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return (0);
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}
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/*
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* Register a new helper hook point.
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*/
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int
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hhook_head_register(int32_t hhook_type, int32_t hhook_id, struct hhook_head **hhh,
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uint32_t flags)
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{
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struct hhook_head *tmphhh;
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tmphhh = hhook_head_get(hhook_type, hhook_id);
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if (tmphhh != NULL) {
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/* Hook point previously registered. */
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hhook_head_release(tmphhh);
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return (EEXIST);
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}
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tmphhh = malloc(sizeof(struct hhook_head), M_HHOOK,
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M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT));
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if (tmphhh == NULL)
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return (ENOMEM);
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tmphhh->hhh_type = hhook_type;
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tmphhh->hhh_id = hhook_id;
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tmphhh->hhh_nhooks = 0;
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STAILQ_INIT(&tmphhh->hhh_hooks);
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HHH_LOCK_INIT(tmphhh);
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if (hhh != NULL) {
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refcount_init(&tmphhh->hhh_refcount, 1);
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*hhh = tmphhh;
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} else
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refcount_init(&tmphhh->hhh_refcount, 0);
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HHHLIST_LOCK();
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if (flags & HHOOK_HEADISINVNET) {
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tmphhh->hhh_flags |= HHH_ISINVNET;
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KASSERT(curvnet != NULL, ("curvnet is NULL"));
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tmphhh->hhh_vid = (uintptr_t)curvnet;
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LIST_INSERT_HEAD(&V_hhook_vhead_list, tmphhh, hhh_vnext);
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}
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LIST_INSERT_HEAD(&hhook_head_list, tmphhh, hhh_next);
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HHHLIST_UNLOCK();
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return (0);
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}
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static void
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hhook_head_destroy(struct hhook_head *hhh)
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{
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struct hhook *tmp, *tmp2;
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HHHLIST_LOCK_ASSERT();
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LIST_REMOVE(hhh, hhh_next);
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if (hhook_head_is_virtualised(hhh) == HHOOK_HEADISINVNET)
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LIST_REMOVE(hhh, hhh_vnext);
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HHH_WLOCK(hhh);
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STAILQ_FOREACH_SAFE(tmp, &hhh->hhh_hooks, hhk_next, tmp2)
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free(tmp, M_HHOOK);
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HHH_WUNLOCK(hhh);
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HHH_LOCK_DESTROY(hhh);
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free(hhh, M_HHOOK);
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}
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/*
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* Remove a helper hook point.
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*/
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int
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hhook_head_deregister(struct hhook_head *hhh)
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{
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int error;
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error = 0;
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HHHLIST_LOCK();
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if (hhh == NULL)
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error = ENOENT;
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else if (hhh->hhh_refcount > 1)
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error = EBUSY;
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else
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hhook_head_destroy(hhh);
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HHHLIST_UNLOCK();
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return (error);
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}
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/*
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* Remove a helper hook point via a hhook_head lookup.
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*/
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int
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hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id)
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{
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struct hhook_head *hhh;
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int error;
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hhh = hhook_head_get(hhook_type, hhook_id);
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error = hhook_head_deregister(hhh);
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if (error == EBUSY)
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hhook_head_release(hhh);
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return (error);
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}
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/*
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* Lookup and return the hhook_head struct associated with the specified type
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* and id, or NULL if not found. If found, the hhook_head's refcount is bumped.
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*/
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struct hhook_head *
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hhook_head_get(int32_t hhook_type, int32_t hhook_id)
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{
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struct hhook_head *hhh;
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HHHLIST_LOCK();
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LIST_FOREACH(hhh, &hhook_head_list, hhh_next) {
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if (hhh->hhh_type == hhook_type && hhh->hhh_id == hhook_id) {
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if (hhook_head_is_virtualised(hhh) ==
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HHOOK_HEADISINVNET) {
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KASSERT(curvnet != NULL, ("curvnet is NULL"));
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if (hhh->hhh_vid != (uintptr_t)curvnet)
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continue;
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}
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refcount_acquire(&hhh->hhh_refcount);
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break;
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}
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}
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HHHLIST_UNLOCK();
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return (hhh);
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}
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void
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hhook_head_release(struct hhook_head *hhh)
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{
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refcount_release(&hhh->hhh_refcount);
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}
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/*
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* Check the hhook_head private flags and return the appropriate public
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* representation of the flag to the caller. The function is implemented in a
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* way that allows us to cope with other subsystems becoming virtualised in the
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* future.
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*/
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uint32_t
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hhook_head_is_virtualised(struct hhook_head *hhh)
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{
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uint32_t ret;
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ret = 0;
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if (hhh != NULL) {
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if (hhh->hhh_flags & HHH_ISINVNET)
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ret = HHOOK_HEADISINVNET;
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}
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return (ret);
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}
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uint32_t
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hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id)
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{
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struct hhook_head *hhh;
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uint32_t ret;
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hhh = hhook_head_get(hook_type, hook_id);
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if (hhh == NULL)
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return (0);
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ret = hhook_head_is_virtualised(hhh);
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hhook_head_release(hhh);
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return (ret);
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}
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/*
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* Vnet created and being initialised.
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*/
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static void
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hhook_vnet_init(const void *unused __unused)
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{
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LIST_INIT(&V_hhook_vhead_list);
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}
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/*
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* Vnet being torn down and destroyed.
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*/
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static void
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hhook_vnet_uninit(const void *unused __unused)
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{
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struct hhook_head *hhh, *tmphhh;
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/*
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* If subsystems which export helper hook points use the hhook KPI
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* correctly, the loop below should have no work to do because the
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* subsystem should have already called hhook_head_deregister().
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*/
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HHHLIST_LOCK();
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LIST_FOREACH_SAFE(hhh, &V_hhook_vhead_list, hhh_vnext, tmphhh) {
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printf("%s: hhook_head type=%d, id=%d cleanup required\n",
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__func__, hhh->hhh_type, hhh->hhh_id);
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hhook_head_destroy(hhh);
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}
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HHHLIST_UNLOCK();
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}
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/*
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* When a vnet is created and being initialised, init the V_hhook_vhead_list.
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*/
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VNET_SYSINIT(hhook_vnet_init, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST,
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hhook_vnet_init, NULL);
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/*
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* The hhook KPI provides a mechanism for subsystems which export helper hook
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* points to clean up on vnet tear down, but in case the KPI is misused,
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* provide a function to clean up and free memory for a vnet being destroyed.
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*/
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VNET_SYSUNINIT(hhook_vnet_uninit, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST,
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hhook_vnet_uninit, NULL);
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