Author: lstewart
Date: Sat May 28 06:56:09 2011
New Revision: 222406
URL: http://svn.freebsd.org/changeset/base/222406

Log:
  MFC r216615,217248,217250:
  
  - Introduce the Hhook (Helper Hook) KPI. The KPI is closely modelled on 
pfil(9),
    and in many respects can be thought of as a more generic superset of pfil.
    Hhook provides a way for kernel subsystems to export hook points that Khelp
    modules can hook to provide enhanced or new functionality to the kernel. The
    KPI has been designed to ensure hook points pose no noticeable overhead when
    no hook functions are registered.
  
  - Introduce the Khelp (Kernel Helpers) KPI. Khelp provides a framework for
    managing Khelp modules, which indirectly use the Hhook KPI to register their
    hook functions with hook points of interest within the kernel. Khelp modules
    aim to provide a structured way to dynamically extend the kernel at runtime 
in
    an ABI preserving manner. Depending on the subsystem providing hook points, 
a
    Khelp module may be able to associate per-object data for maintaining 
relevant
    state between hook calls.
  
  - pjd's Object Specific Data (OSD) KPI is used to manage the per-object data
    allocated to Khelp modules. Create a new "OSD_KHELP" OSD type for use by the
    Khelp framework.
  
  - Bump __FreeBSD_version to 802505 to mark the introduction of the new KPIs.
  
  In collaboration with:        David Hayes <dahayes at swin edu au> and
                                Grenville Armitage <garmitage at swin edu au>
  Sponsored by: FreeBSD Foundation
  Reviewed by:  bz, others along the way

Added:
  stable/8/sys/kern/kern_hhook.c
     - copied, changed from r216615, head/sys/kern/kern_hhook.c
  stable/8/sys/kern/kern_khelp.c
     - copied unchanged from r216615, head/sys/kern/kern_khelp.c
  stable/8/sys/sys/hhook.h
     - copied unchanged from r216615, head/sys/sys/hhook.h
  stable/8/sys/sys/khelp.h
     - copied unchanged from r216615, head/sys/sys/khelp.h
  stable/8/sys/sys/module_khelp.h
     - copied unchanged from r216615, head/sys/sys/module_khelp.h
Modified:
  stable/8/sys/conf/files
  stable/8/sys/sys/osd.h
  stable/8/sys/sys/param.h
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)

Modified: stable/8/sys/conf/files
==============================================================================
--- stable/8/sys/conf/files     Sat May 28 05:40:19 2011        (r222405)
+++ stable/8/sys/conf/files     Sat May 28 06:56:09 2011        (r222406)
@@ -2101,9 +2101,11 @@ kern/kern_exec.c         standard
 kern/kern_exit.c               standard
 kern/kern_fail.c               standard
 kern/kern_fork.c               standard
+kern/kern_hhook.c              standard
 kern/kern_idle.c               standard
 kern/kern_intr.c               standard
 kern/kern_jail.c               standard
+kern/kern_khelp.c              standard
 kern/kern_kthread.c            standard
 kern/kern_ktr.c                        optional ktr
 kern/kern_ktrace.c             standard

Copied and modified: stable/8/sys/kern/kern_hhook.c (from r216615, 
head/sys/kern/kern_hhook.c)
==============================================================================
--- head/sys/kern/kern_hhook.c  Tue Dec 21 13:45:29 2010        (r216615, copy 
source)
+++ stable/8/sys/kern/kern_hhook.c      Sat May 28 06:56:09 2011        
(r222406)
@@ -156,8 +156,7 @@ hhook_add_hook(struct hhook_head *hhh, s
        if (!error) {
                STAILQ_INSERT_TAIL(&hhh->hhh_hooks, hhk, hhk_next);
                hhh->hhh_nhooks++;
-       }
-       else
+       } else
                free(hhk, M_HHOOK);
 
        HHH_WUNLOCK(hhh);
@@ -332,7 +331,6 @@ hhook_head_deregister_lookup(int32_t hho
        struct hhook_head *hhh;
        int error;
 
-       error = 0;
        hhh = hhook_head_get(hhook_type, hhook_id);
        error = hhook_head_deregister(hhh);
 
@@ -356,13 +354,12 @@ hhook_head_get(int32_t hhook_type, int32
        LIST_FOREACH(hhh, &V_hhook_head_list, hhh_next) {
                if (hhh->hhh_type == hhook_type && hhh->hhh_id == hhook_id) {
                        refcount_acquire(&hhh->hhh_refcount);
-                       HHHLIST_UNLOCK();
-                       return (hhh);
+                       break;
                }
        }
        HHHLIST_UNLOCK();
 
-       return (NULL);
+       return (hhh);
 }
 
 void
@@ -383,11 +380,12 @@ hhook_head_is_virtualised(struct hhook_h
 {
        uint32_t ret;
 
-       if (hhh == NULL)
-               return (0);
+       ret = 0;
 
-       if (hhh->hhh_flags & HHH_ISINVNET)
-               ret = HHOOK_HEADISINVNET;
+       if (hhh != NULL) {
+               if (hhh->hhh_flags & HHH_ISINVNET)
+                       ret = HHOOK_HEADISINVNET;
+       }
 
        return (ret);
 }

Copied: stable/8/sys/kern/kern_khelp.c (from r216615, 
head/sys/kern/kern_khelp.c)
==============================================================================
--- /dev/null   00:00:00 1970   (empty, because file is newly added)
+++ stable/8/sys/kern/kern_khelp.c      Sat May 28 06:56:09 2011        
(r222406, copy of r216615, head/sys/kern/kern_khelp.c)
@@ -0,0 +1,471 @@
+/*-
+ * Copyright (c) 2010 Lawrence Stewart <lstew...@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, 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/hhook.h>
+#include <sys/jail.h>
+#include <sys/khelp.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/module_khelp.h>
+#include <sys/osd.h>
+#include <sys/queue.h>
+#include <sys/refcount.h>
+#include <sys/rwlock.h>
+#include <sys/systm.h>
+
+#include <net/vnet.h>
+
+static struct rwlock khelp_list_lock;
+RW_SYSINIT(khelplistlock, &khelp_list_lock, "helper list lock");
+
+static TAILQ_HEAD(helper_head, helper) helpers = 
TAILQ_HEAD_INITIALIZER(helpers);
+
+/* Private function prototypes. */
+static inline void khelp_remove_osd(struct helper *h, struct osd *hosd);
+
+#define        KHELP_LIST_WLOCK() rw_wlock(&khelp_list_lock)
+#define        KHELP_LIST_WUNLOCK() rw_wunlock(&khelp_list_lock)
+#define        KHELP_LIST_RLOCK() rw_rlock(&khelp_list_lock)
+#define        KHELP_LIST_RUNLOCK() rw_runlock(&khelp_list_lock)
+#define        KHELP_LIST_LOCK_ASSERT() rw_assert(&khelp_list_lock, RA_LOCKED)
+
+int
+khelp_register_helper(struct helper *h)
+{
+       struct helper *tmph;
+       int error, i, inserted;
+
+       error = 0;
+       inserted = 0;
+       refcount_init(&h->h_refcount, 0);
+       h->h_id = osd_register(OSD_KHELP, NULL, NULL);
+
+       /* It's only safe to add the hooks after osd_register(). */
+       if (h->h_nhooks > 0) {
+               for (i = 0; i < h->h_nhooks && !error; i++) {
+                       /* We don't require the module to assign hook_helper. */
+                       h->h_hooks[i].hook_helper = h;
+                       error = khelp_add_hhook(&h->h_hooks[i], HHOOK_NOWAIT);
+               }
+
+               if (error) {
+                       for (i--; i >= 0; i--)
+                               khelp_remove_hhook(&h->h_hooks[i]);
+
+                       osd_deregister(OSD_KHELP, h->h_id);
+               }
+       }
+
+       if (!error) {
+               KHELP_LIST_WLOCK();
+               /*
+                * Keep list of helpers sorted in descending h_id order. Due to
+                * the way osd_set() works, a sorted list ensures
+                * init_helper_osd() will operate with improved efficiency.
+                */
+               TAILQ_FOREACH(tmph, &helpers, h_next) {
+                       if (tmph->h_id < h->h_id) {
+                               TAILQ_INSERT_BEFORE(tmph, h, h_next);
+                               inserted = 1;
+                               break;
+                       }
+               }
+
+               if (!inserted)
+                       TAILQ_INSERT_TAIL(&helpers, h, h_next);
+               KHELP_LIST_WUNLOCK();
+       }
+
+       return (error);
+}
+
+int
+khelp_deregister_helper(struct helper *h)
+{
+       struct helper *tmph;
+       int error, i;
+
+       error = 0;
+
+       KHELP_LIST_WLOCK();
+       if (h->h_refcount > 0)
+               error = EBUSY;
+       else {
+               error = ENOENT;
+               TAILQ_FOREACH(tmph, &helpers, h_next) {
+                       if (tmph == h) {
+                               TAILQ_REMOVE(&helpers, h, h_next);
+                               error = 0;
+                               break;
+                       }
+               }
+       }
+       KHELP_LIST_WUNLOCK();
+
+       if (!error) {
+               if (h->h_nhooks > 0) {
+                       for (i = 0; i < h->h_nhooks; i++)
+                               khelp_remove_hhook(&h->h_hooks[i]);
+               }
+               osd_deregister(OSD_KHELP, h->h_id);
+       }
+
+       return (error);
+}
+
+int
+khelp_init_osd(uint32_t classes, struct osd *hosd)
+{
+       struct helper *h;
+       void *hdata;
+       int error;
+
+       KASSERT(hosd != NULL, ("struct osd not initialised!"));
+
+       error = 0;
+
+       KHELP_LIST_RLOCK();
+       TAILQ_FOREACH(h, &helpers, h_next) {
+               /* If helper is correct class and needs to store OSD... */
+               if (h->h_classes & classes && h->h_flags & HELPER_NEEDS_OSD) {
+                       hdata = uma_zalloc(h->h_zone, M_NOWAIT);
+                       if (hdata == NULL) {
+                               error = ENOMEM;
+                               break;
+                       }
+                       osd_set(OSD_KHELP, hosd, h->h_id, hdata);
+                       refcount_acquire(&h->h_refcount);
+               }
+       }
+
+       if (error) {
+               /* Delete OSD that was assigned prior to the error. */
+               TAILQ_FOREACH(h, &helpers, h_next) {
+                       if (h->h_classes & classes)
+                               khelp_remove_osd(h, hosd);
+               }
+       }
+       KHELP_LIST_RUNLOCK();
+
+       return (error);
+}
+
+int
+khelp_destroy_osd(struct osd *hosd)
+{
+       struct helper *h;
+       int error;
+
+       KASSERT(hosd != NULL, ("struct osd not initialised!"));
+
+       error = 0;
+
+       KHELP_LIST_RLOCK();
+       /*
+        * Clean up all khelp related OSD.
+        *
+        * XXXLAS: Would be nice to use something like osd_exit() here but it
+        * doesn't have the right semantics for this purpose.
+        */
+       TAILQ_FOREACH(h, &helpers, h_next)
+               khelp_remove_osd(h, hosd);
+       KHELP_LIST_RUNLOCK();
+
+       return (error);
+}
+
+static inline void
+khelp_remove_osd(struct helper *h, struct osd *hosd)
+{
+       void *hdata;
+
+       if (h->h_flags & HELPER_NEEDS_OSD) {
+               /*
+                * If the current helper uses OSD and calling osd_get()
+                * on the helper's h_id returns non-NULL, the helper has
+                * OSD attached to 'hosd' which needs to be cleaned up.
+                */
+               hdata = osd_get(OSD_KHELP, hosd, h->h_id);
+               if (hdata != NULL) {
+                       uma_zfree(h->h_zone, hdata);
+                       osd_del(OSD_KHELP, hosd, h->h_id);
+                       refcount_release(&h->h_refcount);
+               }
+       }
+}
+
+void *
+khelp_get_osd(struct osd *hosd, int32_t id)
+{
+
+       return (osd_get(OSD_KHELP, hosd, id));
+}
+
+int32_t
+khelp_get_id(char *hname)
+{
+       struct helper *h;
+       int32_t id;
+
+       id = -1;
+
+       KHELP_LIST_RLOCK();
+       TAILQ_FOREACH(h, &helpers, h_next) {
+               if (strncmp(h->h_name, hname, HELPER_NAME_MAXLEN) == 0) {
+                       id = h->h_id;
+                       break;
+               }
+       }
+       KHELP_LIST_RUNLOCK();
+
+       return (id);
+}
+
+int
+khelp_add_hhook(struct hookinfo *hki, uint32_t flags)
+{
+       VNET_ITERATOR_DECL(vnet_iter);
+       int error;
+
+       error = 0;
+
+       /*
+        * XXXLAS: If a helper is dynamically adding a helper hook function at
+        * runtime using this function, we should update the helper's h_hooks
+        * struct member to include the additional hookinfo struct.
+        */
+
+       VNET_LIST_RLOCK_NOSLEEP();
+       VNET_FOREACH(vnet_iter) {
+               CURVNET_SET(vnet_iter);
+               error = hhook_add_hook_lookup(hki, flags);
+               CURVNET_RESTORE();
+#ifdef VIMAGE
+               if (error)
+                       break;
+#endif
+       }
+       VNET_LIST_RUNLOCK_NOSLEEP();
+
+       return (error);
+}
+
+int
+khelp_remove_hhook(struct hookinfo *hki)
+{
+       VNET_ITERATOR_DECL(vnet_iter);
+       int error;
+
+       error = 0;
+
+       /*
+        * XXXLAS: If a helper is dynamically removing a helper hook function at
+        * runtime using this function, we should update the helper's h_hooks
+        * struct member to remove the defunct hookinfo struct.
+        */
+
+       VNET_LIST_RLOCK_NOSLEEP();
+       VNET_FOREACH(vnet_iter) {
+               CURVNET_SET(vnet_iter);
+               error = hhook_remove_hook_lookup(hki);
+               CURVNET_RESTORE();
+#ifdef VIMAGE
+               if (error)
+                       break;
+#endif
+       }
+       VNET_LIST_RUNLOCK_NOSLEEP();
+
+       return (error);
+}
+
+int
+khelp_modevent(module_t mod, int event_type, void *data)
+{
+       struct khelp_modevent_data *kmd;
+       int error;
+
+       kmd = (struct khelp_modevent_data *)data;
+       error = 0;
+
+       switch(event_type) {
+       case MOD_LOAD:
+               if (kmd->helper->h_flags & HELPER_NEEDS_OSD) {
+                       if (kmd->uma_zsize <= 0) {
+                               printf("Use KHELP_DECLARE_MOD_UMA() 
instead!\n");
+                               error = EDOOFUS;
+                               break;
+                       }
+                       kmd->helper->h_zone = uma_zcreate(kmd->name,
+                           kmd->uma_zsize, kmd->umactor, kmd->umadtor, NULL,
+                           NULL, 0, 0);
+                       if (kmd->helper->h_zone == NULL) {
+                               error = ENOMEM;
+                               break;
+                       }
+               }
+               strlcpy(kmd->helper->h_name, kmd->name, HELPER_NAME_MAXLEN);
+               kmd->helper->h_hooks = kmd->hooks;
+               kmd->helper->h_nhooks = kmd->nhooks;
+               if (kmd->helper->mod_init != NULL)
+                       error = kmd->helper->mod_init();
+               if (!error)
+                       error = khelp_register_helper(kmd->helper);
+               break;
+
+       case MOD_QUIESCE:
+       case MOD_SHUTDOWN:
+       case MOD_UNLOAD:
+               error = khelp_deregister_helper(kmd->helper);
+               if (!error) {
+                       if (kmd->helper->h_flags & HELPER_NEEDS_OSD)
+                               uma_zdestroy(kmd->helper->h_zone);
+                       if (kmd->helper->mod_destroy != NULL)
+                               kmd->helper->mod_destroy();
+               } else if (error == ENOENT)
+                       /* Do nothing and allow unload if helper not in list. */
+                       error = 0;
+               else if (error == EBUSY)
+                       printf("Khelp module \"%s\" can't unload until its "
+                           "refcount drops from %d to 0.\n", kmd->name,
+                           kmd->helper->h_refcount);
+               break;
+
+       default:
+               error = EINVAL;
+               break;
+       }
+
+       return (error);
+}
+
+/*
+ * This function is called in two separate situations:
+ *
+ * - When the kernel is booting, it is called directly by the SYSINIT framework
+ * to allow Khelp modules which were compiled into the kernel or loaded by the
+ * boot loader to insert their non-virtualised hook functions into the kernel.
+ *
+ * - When the kernel is booting or a vnet is created, this function is also
+ * called indirectly through khelp_vnet_init() by the vnet initialisation code.
+ * In this situation, Khelp modules are able to insert their virtualised hook
+ * functions into the virtualised hook points in the vnet which is being
+ * initialised. In the case where the kernel is not compiled with "options
+ * VIMAGE", this step is still run once at boot, but the hook functions get
+ * transparently inserted into the standard unvirtualised network stack.
+ */
+static void
+khelp_init(const void *vnet)
+{
+       struct helper *h;
+       int error, i, vinit;
+       int32_t htype, hid;
+
+       error = 0;
+       vinit = vnet != NULL;
+
+       KHELP_LIST_RLOCK();
+       TAILQ_FOREACH(h, &helpers, h_next) {
+               for (i = 0; i < h->h_nhooks && !error; i++) {
+                       htype = h->h_hooks[i].hook_type;
+                       hid = h->h_hooks[i].hook_id;
+
+                       /*
+                        * If we're doing a virtualised init (vinit != 0) and
+                        * the hook point is virtualised, or we're doing a plain
+                        * sysinit at boot and the hook point is not
+                        * virtualised, insert the hook.
+                        */
+                       if ((hhook_head_is_virtualised_lookup(htype, hid) ==
+                           HHOOK_HEADISINVNET && vinit) ||
+                           (!hhook_head_is_virtualised_lookup(htype, hid) &&
+                           !vinit)) {
+                               error = hhook_add_hook_lookup(&h->h_hooks[i],
+                                   HHOOK_NOWAIT);
+                       }
+               }
+
+               if (error) {
+                        /* Remove any helper's hooks we successfully added. */
+                       for (i--; i >= 0; i--)
+                               hhook_remove_hook_lookup(&h->h_hooks[i]);
+
+                       printf("%s: Failed to add hooks for helper \"%s\" (%p)",
+                               __func__, h->h_name, h);
+                       if (vinit)
+                                   printf(" to vnet %p.\n", vnet);
+                       else
+                               printf(".\n");
+
+                       error = 0;
+               }
+       }
+       KHELP_LIST_RUNLOCK();
+}
+
+/*
+ * Vnet created and being initialised.
+ */
+static void
+khelp_vnet_init(const void *unused __unused)
+{
+
+       khelp_init(TD_TO_VNET(curthread));
+}
+
+
+/*
+ * As the kernel boots, allow Khelp modules which were compiled into the kernel
+ * or loaded by the boot loader to insert their non-virtualised hook functions
+ * into the kernel.
+ */
+SYSINIT(khelp_init, SI_SUB_PROTO_END, SI_ORDER_FIRST, khelp_init, NULL);
+
+/*
+ * When a vnet is created and being initialised, we need to insert the helper
+ * hook functions for all currently registered Khelp modules into the vnet's
+ * helper hook points.  The hhook KPI provides a mechanism for subsystems which
+ * export helper hook points to clean up on vnet shutdown, so we don't need a
+ * VNET_SYSUNINIT for Khelp.
+ */
+VNET_SYSINIT(khelp_vnet_init, SI_SUB_PROTO_END, SI_ORDER_FIRST,
+    khelp_vnet_init, NULL);

Copied: stable/8/sys/sys/hhook.h (from r216615, head/sys/sys/hhook.h)
==============================================================================
--- /dev/null   00:00:00 1970   (empty, because file is newly added)
+++ stable/8/sys/sys/hhook.h    Sat May 28 06:56:09 2011        (r222406, copy 
of r216615, head/sys/sys/hhook.h)
@@ -0,0 +1,156 @@
+/*-
+ * Copyright (c) 2010 Lawrence Stewart <lstew...@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, 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'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;
+       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;
+};
+
+/* 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_ */

Copied: stable/8/sys/sys/khelp.h (from r216615, head/sys/sys/khelp.h)
==============================================================================
--- /dev/null   00:00:00 1970   (empty, because file is newly added)
+++ stable/8/sys/sys/khelp.h    Sat May 28 06:56:09 2011        (r222406, copy 
of r216615, head/sys/sys/khelp.h)
@@ -0,0 +1,76 @@
+/*-
+ * Copyright (c) 2010 Lawrence Stewart <lstew...@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, 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 for managing kernel helper modules which perform useful functionality
+ * within the kernel. Originally released as part of the NewTCP research
+ * project at Swinburne University'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_KHELP_H_
+#define        _SYS_KHELP_H_
+
+struct helper;
+struct hookinfo;
+struct osd;
+
+/* Helper classes. */
+#define        HELPER_CLASS_TCP        0x00000001
+
+/* Public KPI functions. */
+int    khelp_register_helper(struct helper *h);
+
+int    khelp_deregister_helper(struct helper *h);
+
+int    khelp_init_osd(uint32_t classes, struct osd *hosd);
+
+int    khelp_destroy_osd(struct osd *hosd);
+
+void * khelp_get_osd(struct osd *hosd, int32_t id);
+
+int32_t        khelp_get_id(char *hname);
+
+int    khelp_add_hhook(struct hookinfo *hki, uint32_t flags);
+
+int    khelp_remove_hhook(struct hookinfo *hki);
+
+#endif /* _SYS_KHELP_H_ */

Copied: stable/8/sys/sys/module_khelp.h (from r216615, 
head/sys/sys/module_khelp.h)
==============================================================================
--- /dev/null   00:00:00 1970   (empty, because file is newly added)
+++ stable/8/sys/sys/module_khelp.h     Sat May 28 06:56:09 2011        
(r222406, copy of r216615, head/sys/sys/module_khelp.h)
@@ -0,0 +1,110 @@
+/*-
+ * Copyright (c) 2010 Lawrence Stewart <lstew...@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, 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_MODULE_KHELP_H_
+#define _SYS_MODULE_KHELP_H_
+
+/* XXXLAS: Needed for uma related typedefs. */
+#include <vm/uma.h>
+
+/* Helper flags. */
+#define        HELPER_NEEDS_OSD        0x0001
+
+struct helper {
+       int (*mod_init) (void);
+       int (*mod_destroy) (void);
+#define        HELPER_NAME_MAXLEN 16
+       char                    h_name[HELPER_NAME_MAXLEN];
+       uma_zone_t              h_zone;
+       struct hookinfo         *h_hooks;
+       uint32_t                h_nhooks;
+       uint32_t                h_classes;
+       int32_t                 h_id;
+       volatile uint32_t       h_refcount;
+       uint16_t                h_flags;
+       TAILQ_ENTRY(helper)     h_next;
+};
+
+struct khelp_modevent_data {
+       char                    name[HELPER_NAME_MAXLEN];
+       struct helper           *helper;
+       struct hookinfo         *hooks;
+       int                     nhooks;
+       int                     uma_zsize;
+       uma_ctor                umactor;
+       uma_dtor                umadtor;
+};
+
+#define        KHELP_DECLARE_MOD(hname, hdata, hhooks, version)                
\
+       static struct khelp_modevent_data kmd_##hname = {               \
+               .name = #hname,                                         \
+               .helper = hdata                                         \
+               .hooks = hhooks,                                        \
+               .nhooks = sizeof(hhooks) / sizeof(hhooks[0]),           \
+       };                                                              \
+       static moduledata_t h_##hname = {                               \
+               .name = #hname,                                         \
+               .evhand = khelp_modevent,                               \
+               .priv = &kmd_##hname                                    \
+       };                                                              \
+       DECLARE_MODULE(hname, h_##hname, SI_SUB_PROTO_IFATTACHDOMAIN,   \
+           SI_ORDER_ANY);                                              \
+       MODULE_VERSION(hname, version)
+
+#define        KHELP_DECLARE_MOD_UMA(hname, hdata, hhooks, version, size, 
ctor, dtor) \
+       static struct khelp_modevent_data kmd_##hname = {               \
+               .name = #hname,                                         \
+               .helper = hdata,                                        \
+               .hooks = hhooks,                                        \
+               .nhooks = sizeof(hhooks) / sizeof(hhooks[0]),           \
+               .uma_zsize = size,                                      \
+               .umactor = ctor,                                        \
+               .umadtor = dtor                                         \
+       };                                                              \
+       static moduledata_t h_##hname = {                               \
+               .name = #hname,                                         \
+               .evhand = khelp_modevent,                               \
+               .priv = &kmd_##hname                                    \
+       };                                                              \
+       DECLARE_MODULE(hname, h_##hname, SI_SUB_PROTO_IFATTACHDOMAIN,   \
+           SI_ORDER_ANY);                                              \
+       MODULE_VERSION(hname, version)
+
+int    khelp_modevent(module_t mod, int type, void *data);
+
+#endif /* _SYS_MODULE_KHELP_H_ */

Modified: stable/8/sys/sys/osd.h
==============================================================================
--- stable/8/sys/sys/osd.h      Sat May 28 05:40:19 2011        (r222405)
+++ stable/8/sys/sys/osd.h      Sat May 28 06:56:09 2011        (r222406)
@@ -46,9 +46,10 @@ struct osd {
 
 #define        OSD_THREAD      0
 #define        OSD_JAIL        1
+#define        OSD_KHELP       2
 
 #define        OSD_FIRST       OSD_THREAD
-#define        OSD_LAST        OSD_JAIL
+#define        OSD_LAST        OSD_KHELP
 
 typedef void (*osd_destructor_t)(void *value);
 typedef int (*osd_method_t)(void *obj, void *data);

Modified: stable/8/sys/sys/param.h
==============================================================================
--- stable/8/sys/sys/param.h    Sat May 28 05:40:19 2011        (r222405)
+++ stable/8/sys/sys/param.h    Sat May 28 06:56:09 2011        (r222406)
@@ -58,7 +58,7 @@
  *             in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 802504       /* Master, propagated to newvers */
+#define __FreeBSD_version 802505       /* Master, propagated to newvers */
 
 #ifdef _KERNEL
 #define        P_OSREL_SIGSEGV         700004
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