freebsd-dev/sys/kern/kern_khelp.c
Lawrence Stewart 891b8ed467 Use the full and proper company name for Swinburne University of Technology
throughout the source tree.

Requested by:	Grenville Armitage, Director of CAIA at Swinburne University of
			Technology
MFC after:	3 days
2011-04-12 08:13:18 +00:00

472 lines
12 KiB
C

/*-
* Copyright (c) 2010 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.
*/
#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);