1/*-
2 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
3 * Copyright (c) 2010 The FreeBSD Foundation
4 * All rights reserved.
5 *
6 * This software was developed by Lawrence Stewart while studying at the Centre
7 * for Advanced Internet Architectures, Swinburne University of Technology,
8 * made possible in part by grants from the FreeBSD Foundation and Cisco
9 * University Research Program Fund at Community Foundation Silicon Valley.
10 *
11 * Portions of this software were developed at the Centre for Advanced
12 * Internet Architectures, Swinburne University of Technology, Melbourne,
13 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/sys/kern/kern_hhook.c 220592 2011-04-13 11:28:46Z pluknet $");
39
40#include <sys/param.h>
41#include <sys/kernel.h>
42#include <sys/hhook.h>
43#include <sys/khelp.h>
44#include <sys/malloc.h>
45#include <sys/module.h>
46#include <sys/module_khelp.h>
47#include <sys/osd.h>
48#include <sys/queue.h>
49#include <sys/refcount.h>
50#include <sys/systm.h>
51
52#include <net/vnet.h>
53
54struct hhook {
55 hhook_func_t hhk_func;
56 struct helper *hhk_helper;
57 void *hhk_udata;
58 STAILQ_ENTRY(hhook) hhk_next;
59};
60
61static MALLOC_DEFINE(M_HHOOK, "hhook", "Helper hooks are linked off hhook_head lists");
62
63LIST_HEAD(hhookheadhead, hhook_head);
64VNET_DEFINE(struct hhookheadhead, hhook_head_list);
65#define V_hhook_head_list VNET(hhook_head_list)
66
67static struct mtx hhook_head_list_lock;
68MTX_SYSINIT(hhookheadlistlock, &hhook_head_list_lock, "hhook_head list lock",
69 MTX_DEF);
70
71/* Private function prototypes. */
72static void hhook_head_destroy(struct hhook_head *hhh);
73
74#define HHHLIST_LOCK() mtx_lock(&hhook_head_list_lock)
75#define HHHLIST_UNLOCK() mtx_unlock(&hhook_head_list_lock)
76#define HHHLIST_LOCK_ASSERT() mtx_assert(&hhook_head_list_lock, MA_OWNED)
77
78#define HHH_LOCK_INIT(hhh) rm_init(&(hhh)->hhh_lock, "hhook_head rm lock")
79#define HHH_LOCK_DESTROY(hhh) rm_destroy(&(hhh)->hhh_lock)
80#define HHH_WLOCK(hhh) rm_wlock(&(hhh)->hhh_lock)
81#define HHH_WUNLOCK(hhh) rm_wunlock(&(hhh)->hhh_lock)
82#define HHH_RLOCK(hhh, rmpt) rm_rlock(&(hhh)->hhh_lock, (rmpt))
83#define HHH_RUNLOCK(hhh, rmpt) rm_runlock(&(hhh)->hhh_lock, (rmpt))
84
85/*
86 * Run all helper hook functions for a given hook point.
87 */
88void
89hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd)
90{
91 struct hhook *hhk;
92 void *hdata;
93 struct rm_priotracker rmpt;
94
95 KASSERT(hhh->hhh_refcount > 0, ("hhook_head %p refcount is 0", hhh));
96
97 HHH_RLOCK(hhh, &rmpt);
98 STAILQ_FOREACH(hhk, &hhh->hhh_hooks, hhk_next) {
99 if (hhk->hhk_helper->h_flags & HELPER_NEEDS_OSD) {
100 hdata = osd_get(OSD_KHELP, hosd, hhk->hhk_helper->h_id);
101 if (hdata == NULL)
102 continue;
103 } else
104 hdata = NULL;
105
106 /*
107 * XXXLAS: We currently ignore the int returned by the hook,
108 * but will likely want to handle it in future to allow hhook to
109 * be used like pfil and effect changes at the hhook calling
110 * site e.g. we could define a new hook type of HHOOK_TYPE_PFIL
111 * and standardise what particular return values mean and set
112 * the context data to pass exactly the same information as pfil
113 * hooks currently receive, thus replicating pfil with hhook.
114 */
115 hhk->hhk_func(hhh->hhh_type, hhh->hhh_id, hhk->hhk_udata,
116 ctx_data, hdata, hosd);
117 }
118 HHH_RUNLOCK(hhh, &rmpt);
119}
120
121/*
122 * Register a new helper hook function with a helper hook point.
123 */
124int
125hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki, uint32_t flags)
126{
127 struct hhook *hhk, *tmp;
128 int error;
129
130 error = 0;
131
132 if (hhh == NULL)
133 return (ENOENT);
134
135 hhk = malloc(sizeof(struct hhook), M_HHOOK,
136 M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT));
137
138 if (hhk == NULL)
139 return (ENOMEM);
140
141 hhk->hhk_helper = hki->hook_helper;
142 hhk->hhk_func = hki->hook_func;
143 hhk->hhk_udata = hki->hook_udata;
144
145 HHH_WLOCK(hhh);
146 STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) {
147 if (tmp->hhk_func == hki->hook_func &&
148 tmp->hhk_udata == hki->hook_udata) {
149 /* The helper hook function is already registered. */
150 error = EEXIST;
151 break;
152 }
153 }
154
155 if (!error) {
156 STAILQ_INSERT_TAIL(&hhh->hhh_hooks, hhk, hhk_next);
157 hhh->hhh_nhooks++;
158 } else
159 free(hhk, M_HHOOK);
160
161 HHH_WUNLOCK(hhh);
162
163 return (error);
164}
165
166/*
167 * Lookup a helper hook point and register a new helper hook function with it.
168 */
169int
170hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags)
171{
172 struct hhook_head *hhh;
173 int error;
174
175 hhh = hhook_head_get(hki->hook_type, hki->hook_id);
176
177 if (hhh == NULL)
178 return (ENOENT);
179
180 error = hhook_add_hook(hhh, hki, flags);
181 hhook_head_release(hhh);
182
183 return (error);
184}
185
186/*
187 * Remove a helper hook function from a helper hook point.
188 */
189int
190hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki)
191{
192 struct hhook *tmp;
193
194 if (hhh == NULL)
195 return (ENOENT);
196
197 HHH_WLOCK(hhh);
198 STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) {
199 if (tmp->hhk_func == hki->hook_func &&
200 tmp->hhk_udata == hki->hook_udata) {
201 STAILQ_REMOVE(&hhh->hhh_hooks, tmp, hhook, hhk_next);
202 free(tmp, M_HHOOK);
203 hhh->hhh_nhooks--;
204 break;
205 }
206 }
207 HHH_WUNLOCK(hhh);
208
209 return (0);
210}
211
212/*
213 * Lookup a helper hook point and remove a helper hook function from it.
214 */
215int
216hhook_remove_hook_lookup(struct hookinfo *hki)
217{
218 struct hhook_head *hhh;
219
220 hhh = hhook_head_get(hki->hook_type, hki->hook_id);
221
222 if (hhh == NULL)
223 return (ENOENT);
224
225 hhook_remove_hook(hhh, hki);
226 hhook_head_release(hhh);
227
228 return (0);
229}
230
231/*
232 * Register a new helper hook point.
233 */
234int
235hhook_head_register(int32_t hhook_type, int32_t hhook_id, struct hhook_head **hhh,
236 uint32_t flags)
237{
238 struct hhook_head *tmphhh;
239
240 tmphhh = hhook_head_get(hhook_type, hhook_id);
241
242 if (tmphhh != NULL) {
243 /* Hook point previously registered. */
244 hhook_head_release(tmphhh);
245 return (EEXIST);
246 }
247
248 /* XXXLAS: Need to implement support for non-virtualised hooks. */
249 if ((flags & HHOOK_HEADISINVNET) == 0) {
250 printf("%s: only vnet-style virtualised hooks can be used\n",
251 __func__);
252 return (EINVAL);
253 }
254
255 tmphhh = malloc(sizeof(struct hhook_head), M_HHOOK,
256 M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT));
257
258 if (tmphhh == NULL)
259 return (ENOMEM);
260
261 tmphhh->hhh_type = hhook_type;
262 tmphhh->hhh_id = hhook_id;
263 tmphhh->hhh_nhooks = 0;
264 STAILQ_INIT(&tmphhh->hhh_hooks);
265 HHH_LOCK_INIT(tmphhh);
266
267 if (hhh != NULL)
268 refcount_init(&tmphhh->hhh_refcount, 1);
269 else
270 refcount_init(&tmphhh->hhh_refcount, 0);
271
272 if (flags & HHOOK_HEADISINVNET) {
273 tmphhh->hhh_flags |= HHH_ISINVNET;
274 HHHLIST_LOCK();
275 LIST_INSERT_HEAD(&V_hhook_head_list, tmphhh, hhh_next);
276 HHHLIST_UNLOCK();
277 } else {
278 /* XXXLAS: Add tmphhh to the non-virtualised list. */
279 }
280
281 *hhh = tmphhh;
282
283 return (0);
284}
285
286static void
287hhook_head_destroy(struct hhook_head *hhh)
288{
289 struct hhook *tmp, *tmp2;
290
291 HHHLIST_LOCK_ASSERT();
292
293 LIST_REMOVE(hhh, hhh_next);
294 HHH_WLOCK(hhh);
295 STAILQ_FOREACH_SAFE(tmp, &hhh->hhh_hooks, hhk_next, tmp2)
296 free(tmp, M_HHOOK);
297 HHH_WUNLOCK(hhh);
298 HHH_LOCK_DESTROY(hhh);
299 free(hhh, M_HHOOK);
300}
301
302/*
303 * Remove a helper hook point.
304 */
305int
306hhook_head_deregister(struct hhook_head *hhh)
307{
308 int error;
309
310 error = 0;
311
312 HHHLIST_LOCK();
313 if (hhh == NULL)
314 error = ENOENT;
315 else if (hhh->hhh_refcount > 1)
316 error = EBUSY;
317 else
318 hhook_head_destroy(hhh);
319 HHHLIST_UNLOCK();
320
321 return (error);
322}
323
324/*
325 * Remove a helper hook point via a hhook_head lookup.
326 */
327int
328hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id)
329{
330 struct hhook_head *hhh;
331 int error;
332
333 hhh = hhook_head_get(hhook_type, hhook_id);
334 error = hhook_head_deregister(hhh);
335
336 if (error == EBUSY)
337 hhook_head_release(hhh);
338
339 return (error);
340}
341
342/*
343 * Lookup and return the hhook_head struct associated with the specified type
344 * and id, or NULL if not found. If found, the hhook_head's refcount is bumped.
345 */
346struct hhook_head *
347hhook_head_get(int32_t hhook_type, int32_t hhook_id)
348{
349 struct hhook_head *hhh;
350
351 /* XXXLAS: Pick hhook_head_list based on hhook_head flags. */
352 HHHLIST_LOCK();
353 LIST_FOREACH(hhh, &V_hhook_head_list, hhh_next) {
354 if (hhh->hhh_type == hhook_type && hhh->hhh_id == hhook_id) {
355 refcount_acquire(&hhh->hhh_refcount);
356 break;
357 }
358 }
359 HHHLIST_UNLOCK();
360
361 return (hhh);
362}
363
364void
365hhook_head_release(struct hhook_head *hhh)
366{
367
368 refcount_release(&hhh->hhh_refcount);
369}
370
371/*
372 * Check the hhook_head private flags and return the appropriate public
373 * representation of the flag to the caller. The function is implemented in a
374 * way that allows us to cope with other subsystems becoming virtualised in the
375 * future.
376 */
377uint32_t
378hhook_head_is_virtualised(struct hhook_head *hhh)
379{
380 uint32_t ret;
381
382 ret = 0;
383
384 if (hhh != NULL) {
385 if (hhh->hhh_flags & HHH_ISINVNET)
386 ret = HHOOK_HEADISINVNET;
387 }
388
389 return (ret);
390}
391
392uint32_t
393hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id)
394{
395 struct hhook_head *hhh;
396 uint32_t ret;
397
398 hhh = hhook_head_get(hook_type, hook_id);
399
400 if (hhh == NULL)
401 return (0);
402
403 ret = hhook_head_is_virtualised(hhh);
404 hhook_head_release(hhh);
405
406 return (ret);
407}
408
409/*
410 * Vnet created and being initialised.
411 */
412static void
413hhook_vnet_init(const void *unused __unused)
414{
415
416 LIST_INIT(&V_hhook_head_list);
417}
418
419/*
420 * Vnet being torn down and destroyed.
421 */
422static void
423hhook_vnet_uninit(const void *unused __unused)
424{
425 struct hhook_head *hhh, *tmphhh;
426
427 /*
428 * If subsystems which export helper hook points use the hhook KPI
429 * correctly, the loop below should have no work to do because the
430 * subsystem should have already called hhook_head_deregister().
431 */
432 HHHLIST_LOCK();
433 LIST_FOREACH_SAFE(hhh, &V_hhook_head_list, hhh_next, tmphhh) {
434 printf("%s: hhook_head type=%d, id=%d cleanup required\n",
435 __func__, hhh->hhh_type, hhh->hhh_id);
436 hhook_head_destroy(hhh);
437 }
438 HHHLIST_UNLOCK();
439}
440
441
442/*
443 * When a vnet is created and being initialised, init the V_hhook_head_list.
444 */
445VNET_SYSINIT(hhook_vnet_init, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST,
446 hhook_vnet_init, NULL);
447
448/*
449 * The hhook KPI provides a mechanism for subsystems which export helper hook
450 * points to clean up on vnet tear down, but in case the KPI is misused,
451 * provide a function to clean up and free memory for a vnet being destroyed.
452 */
453VNET_SYSUNINIT(hhook_vnet_uninit, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST,
454 hhook_vnet_uninit, NULL);
2 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
3 * Copyright (c) 2010 The FreeBSD Foundation
4 * All rights reserved.
5 *
6 * This software was developed by Lawrence Stewart while studying at the Centre
7 * for Advanced Internet Architectures, Swinburne University of Technology,
8 * made possible in part by grants from the FreeBSD Foundation and Cisco
9 * University Research Program Fund at Community Foundation Silicon Valley.
10 *
11 * Portions of this software were developed at the Centre for Advanced
12 * Internet Architectures, Swinburne University of Technology, Melbourne,
13 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/sys/kern/kern_hhook.c 220592 2011-04-13 11:28:46Z pluknet $");
39
40#include <sys/param.h>
41#include <sys/kernel.h>
42#include <sys/hhook.h>
43#include <sys/khelp.h>
44#include <sys/malloc.h>
45#include <sys/module.h>
46#include <sys/module_khelp.h>
47#include <sys/osd.h>
48#include <sys/queue.h>
49#include <sys/refcount.h>
50#include <sys/systm.h>
51
52#include <net/vnet.h>
53
54struct hhook {
55 hhook_func_t hhk_func;
56 struct helper *hhk_helper;
57 void *hhk_udata;
58 STAILQ_ENTRY(hhook) hhk_next;
59};
60
61static MALLOC_DEFINE(M_HHOOK, "hhook", "Helper hooks are linked off hhook_head lists");
62
63LIST_HEAD(hhookheadhead, hhook_head);
64VNET_DEFINE(struct hhookheadhead, hhook_head_list);
65#define V_hhook_head_list VNET(hhook_head_list)
66
67static struct mtx hhook_head_list_lock;
68MTX_SYSINIT(hhookheadlistlock, &hhook_head_list_lock, "hhook_head list lock",
69 MTX_DEF);
70
71/* Private function prototypes. */
72static void hhook_head_destroy(struct hhook_head *hhh);
73
74#define HHHLIST_LOCK() mtx_lock(&hhook_head_list_lock)
75#define HHHLIST_UNLOCK() mtx_unlock(&hhook_head_list_lock)
76#define HHHLIST_LOCK_ASSERT() mtx_assert(&hhook_head_list_lock, MA_OWNED)
77
78#define HHH_LOCK_INIT(hhh) rm_init(&(hhh)->hhh_lock, "hhook_head rm lock")
79#define HHH_LOCK_DESTROY(hhh) rm_destroy(&(hhh)->hhh_lock)
80#define HHH_WLOCK(hhh) rm_wlock(&(hhh)->hhh_lock)
81#define HHH_WUNLOCK(hhh) rm_wunlock(&(hhh)->hhh_lock)
82#define HHH_RLOCK(hhh, rmpt) rm_rlock(&(hhh)->hhh_lock, (rmpt))
83#define HHH_RUNLOCK(hhh, rmpt) rm_runlock(&(hhh)->hhh_lock, (rmpt))
84
85/*
86 * Run all helper hook functions for a given hook point.
87 */
88void
89hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd)
90{
91 struct hhook *hhk;
92 void *hdata;
93 struct rm_priotracker rmpt;
94
95 KASSERT(hhh->hhh_refcount > 0, ("hhook_head %p refcount is 0", hhh));
96
97 HHH_RLOCK(hhh, &rmpt);
98 STAILQ_FOREACH(hhk, &hhh->hhh_hooks, hhk_next) {
99 if (hhk->hhk_helper->h_flags & HELPER_NEEDS_OSD) {
100 hdata = osd_get(OSD_KHELP, hosd, hhk->hhk_helper->h_id);
101 if (hdata == NULL)
102 continue;
103 } else
104 hdata = NULL;
105
106 /*
107 * XXXLAS: We currently ignore the int returned by the hook,
108 * but will likely want to handle it in future to allow hhook to
109 * be used like pfil and effect changes at the hhook calling
110 * site e.g. we could define a new hook type of HHOOK_TYPE_PFIL
111 * and standardise what particular return values mean and set
112 * the context data to pass exactly the same information as pfil
113 * hooks currently receive, thus replicating pfil with hhook.
114 */
115 hhk->hhk_func(hhh->hhh_type, hhh->hhh_id, hhk->hhk_udata,
116 ctx_data, hdata, hosd);
117 }
118 HHH_RUNLOCK(hhh, &rmpt);
119}
120
121/*
122 * Register a new helper hook function with a helper hook point.
123 */
124int
125hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki, uint32_t flags)
126{
127 struct hhook *hhk, *tmp;
128 int error;
129
130 error = 0;
131
132 if (hhh == NULL)
133 return (ENOENT);
134
135 hhk = malloc(sizeof(struct hhook), M_HHOOK,
136 M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT));
137
138 if (hhk == NULL)
139 return (ENOMEM);
140
141 hhk->hhk_helper = hki->hook_helper;
142 hhk->hhk_func = hki->hook_func;
143 hhk->hhk_udata = hki->hook_udata;
144
145 HHH_WLOCK(hhh);
146 STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) {
147 if (tmp->hhk_func == hki->hook_func &&
148 tmp->hhk_udata == hki->hook_udata) {
149 /* The helper hook function is already registered. */
150 error = EEXIST;
151 break;
152 }
153 }
154
155 if (!error) {
156 STAILQ_INSERT_TAIL(&hhh->hhh_hooks, hhk, hhk_next);
157 hhh->hhh_nhooks++;
158 } else
159 free(hhk, M_HHOOK);
160
161 HHH_WUNLOCK(hhh);
162
163 return (error);
164}
165
166/*
167 * Lookup a helper hook point and register a new helper hook function with it.
168 */
169int
170hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags)
171{
172 struct hhook_head *hhh;
173 int error;
174
175 hhh = hhook_head_get(hki->hook_type, hki->hook_id);
176
177 if (hhh == NULL)
178 return (ENOENT);
179
180 error = hhook_add_hook(hhh, hki, flags);
181 hhook_head_release(hhh);
182
183 return (error);
184}
185
186/*
187 * Remove a helper hook function from a helper hook point.
188 */
189int
190hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki)
191{
192 struct hhook *tmp;
193
194 if (hhh == NULL)
195 return (ENOENT);
196
197 HHH_WLOCK(hhh);
198 STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) {
199 if (tmp->hhk_func == hki->hook_func &&
200 tmp->hhk_udata == hki->hook_udata) {
201 STAILQ_REMOVE(&hhh->hhh_hooks, tmp, hhook, hhk_next);
202 free(tmp, M_HHOOK);
203 hhh->hhh_nhooks--;
204 break;
205 }
206 }
207 HHH_WUNLOCK(hhh);
208
209 return (0);
210}
211
212/*
213 * Lookup a helper hook point and remove a helper hook function from it.
214 */
215int
216hhook_remove_hook_lookup(struct hookinfo *hki)
217{
218 struct hhook_head *hhh;
219
220 hhh = hhook_head_get(hki->hook_type, hki->hook_id);
221
222 if (hhh == NULL)
223 return (ENOENT);
224
225 hhook_remove_hook(hhh, hki);
226 hhook_head_release(hhh);
227
228 return (0);
229}
230
231/*
232 * Register a new helper hook point.
233 */
234int
235hhook_head_register(int32_t hhook_type, int32_t hhook_id, struct hhook_head **hhh,
236 uint32_t flags)
237{
238 struct hhook_head *tmphhh;
239
240 tmphhh = hhook_head_get(hhook_type, hhook_id);
241
242 if (tmphhh != NULL) {
243 /* Hook point previously registered. */
244 hhook_head_release(tmphhh);
245 return (EEXIST);
246 }
247
248 /* XXXLAS: Need to implement support for non-virtualised hooks. */
249 if ((flags & HHOOK_HEADISINVNET) == 0) {
250 printf("%s: only vnet-style virtualised hooks can be used\n",
251 __func__);
252 return (EINVAL);
253 }
254
255 tmphhh = malloc(sizeof(struct hhook_head), M_HHOOK,
256 M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT));
257
258 if (tmphhh == NULL)
259 return (ENOMEM);
260
261 tmphhh->hhh_type = hhook_type;
262 tmphhh->hhh_id = hhook_id;
263 tmphhh->hhh_nhooks = 0;
264 STAILQ_INIT(&tmphhh->hhh_hooks);
265 HHH_LOCK_INIT(tmphhh);
266
267 if (hhh != NULL)
268 refcount_init(&tmphhh->hhh_refcount, 1);
269 else
270 refcount_init(&tmphhh->hhh_refcount, 0);
271
272 if (flags & HHOOK_HEADISINVNET) {
273 tmphhh->hhh_flags |= HHH_ISINVNET;
274 HHHLIST_LOCK();
275 LIST_INSERT_HEAD(&V_hhook_head_list, tmphhh, hhh_next);
276 HHHLIST_UNLOCK();
277 } else {
278 /* XXXLAS: Add tmphhh to the non-virtualised list. */
279 }
280
281 *hhh = tmphhh;
282
283 return (0);
284}
285
286static void
287hhook_head_destroy(struct hhook_head *hhh)
288{
289 struct hhook *tmp, *tmp2;
290
291 HHHLIST_LOCK_ASSERT();
292
293 LIST_REMOVE(hhh, hhh_next);
294 HHH_WLOCK(hhh);
295 STAILQ_FOREACH_SAFE(tmp, &hhh->hhh_hooks, hhk_next, tmp2)
296 free(tmp, M_HHOOK);
297 HHH_WUNLOCK(hhh);
298 HHH_LOCK_DESTROY(hhh);
299 free(hhh, M_HHOOK);
300}
301
302/*
303 * Remove a helper hook point.
304 */
305int
306hhook_head_deregister(struct hhook_head *hhh)
307{
308 int error;
309
310 error = 0;
311
312 HHHLIST_LOCK();
313 if (hhh == NULL)
314 error = ENOENT;
315 else if (hhh->hhh_refcount > 1)
316 error = EBUSY;
317 else
318 hhook_head_destroy(hhh);
319 HHHLIST_UNLOCK();
320
321 return (error);
322}
323
324/*
325 * Remove a helper hook point via a hhook_head lookup.
326 */
327int
328hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id)
329{
330 struct hhook_head *hhh;
331 int error;
332
333 hhh = hhook_head_get(hhook_type, hhook_id);
334 error = hhook_head_deregister(hhh);
335
336 if (error == EBUSY)
337 hhook_head_release(hhh);
338
339 return (error);
340}
341
342/*
343 * Lookup and return the hhook_head struct associated with the specified type
344 * and id, or NULL if not found. If found, the hhook_head's refcount is bumped.
345 */
346struct hhook_head *
347hhook_head_get(int32_t hhook_type, int32_t hhook_id)
348{
349 struct hhook_head *hhh;
350
351 /* XXXLAS: Pick hhook_head_list based on hhook_head flags. */
352 HHHLIST_LOCK();
353 LIST_FOREACH(hhh, &V_hhook_head_list, hhh_next) {
354 if (hhh->hhh_type == hhook_type && hhh->hhh_id == hhook_id) {
355 refcount_acquire(&hhh->hhh_refcount);
356 break;
357 }
358 }
359 HHHLIST_UNLOCK();
360
361 return (hhh);
362}
363
364void
365hhook_head_release(struct hhook_head *hhh)
366{
367
368 refcount_release(&hhh->hhh_refcount);
369}
370
371/*
372 * Check the hhook_head private flags and return the appropriate public
373 * representation of the flag to the caller. The function is implemented in a
374 * way that allows us to cope with other subsystems becoming virtualised in the
375 * future.
376 */
377uint32_t
378hhook_head_is_virtualised(struct hhook_head *hhh)
379{
380 uint32_t ret;
381
382 ret = 0;
383
384 if (hhh != NULL) {
385 if (hhh->hhh_flags & HHH_ISINVNET)
386 ret = HHOOK_HEADISINVNET;
387 }
388
389 return (ret);
390}
391
392uint32_t
393hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id)
394{
395 struct hhook_head *hhh;
396 uint32_t ret;
397
398 hhh = hhook_head_get(hook_type, hook_id);
399
400 if (hhh == NULL)
401 return (0);
402
403 ret = hhook_head_is_virtualised(hhh);
404 hhook_head_release(hhh);
405
406 return (ret);
407}
408
409/*
410 * Vnet created and being initialised.
411 */
412static void
413hhook_vnet_init(const void *unused __unused)
414{
415
416 LIST_INIT(&V_hhook_head_list);
417}
418
419/*
420 * Vnet being torn down and destroyed.
421 */
422static void
423hhook_vnet_uninit(const void *unused __unused)
424{
425 struct hhook_head *hhh, *tmphhh;
426
427 /*
428 * If subsystems which export helper hook points use the hhook KPI
429 * correctly, the loop below should have no work to do because the
430 * subsystem should have already called hhook_head_deregister().
431 */
432 HHHLIST_LOCK();
433 LIST_FOREACH_SAFE(hhh, &V_hhook_head_list, hhh_next, tmphhh) {
434 printf("%s: hhook_head type=%d, id=%d cleanup required\n",
435 __func__, hhh->hhh_type, hhh->hhh_id);
436 hhook_head_destroy(hhh);
437 }
438 HHHLIST_UNLOCK();
439}
440
441
442/*
443 * When a vnet is created and being initialised, init the V_hhook_head_list.
444 */
445VNET_SYSINIT(hhook_vnet_init, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST,
446 hhook_vnet_init, NULL);
447
448/*
449 * The hhook KPI provides a mechanism for subsystems which export helper hook
450 * points to clean up on vnet tear down, but in case the KPI is misused,
451 * provide a function to clean up and free memory for a vnet being destroyed.
452 */
453VNET_SYSUNINIT(hhook_vnet_uninit, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST,
454 hhook_vnet_uninit, NULL);