1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2004-2009 University of Zagreb
5 * Copyright (c) 2006-2009 FreeBSD Foundation
6 * All rights reserved.
7 *
8 * This software was developed by the University of Zagreb and the
9 * FreeBSD Foundation under sponsorship by the Stichting NLnet and the
10 * FreeBSD Foundation.
11 *
12 * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
13 * Copyright (c) 2009 Robert N. M. Watson
14 * All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 */
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD$");
40
41#include "opt_ddb.h"
42#include "opt_kdb.h"
43
44#include <sys/param.h>
45#include <sys/kdb.h>
46#include <sys/kernel.h>
47#include <sys/jail.h>
48#include <sys/sdt.h>
49#include <sys/systm.h>
50#include <sys/sysctl.h>
51#include <sys/eventhandler.h>
52#include <sys/lock.h>
53#include <sys/malloc.h>
54#include <sys/proc.h>
55#include <sys/socket.h>
56#include <sys/sx.h>
57#include <sys/sysctl.h>
58
59#include <machine/stdarg.h>
60
61#ifdef DDB
62#include <ddb/ddb.h>
63#include <ddb/db_sym.h>
64#endif
65
66#include <net/if.h>
67#include <net/if_var.h>
68#include <net/vnet.h>
69
70/*-
71 * This file implements core functions for virtual network stacks:
72 *
73 * - Virtual network stack management functions.
74 *
75 * - Virtual network stack memory allocator, which virtualizes global
76 *   variables in the network stack
77 *
78 * - Virtualized SYSINIT's/SYSUNINIT's, which allow network stack subsystems
79 *   to register startup/shutdown events to be run for each virtual network
80 *   stack instance.
81 */
82
83FEATURE(vimage, "VIMAGE kernel virtualization");
84
85static MALLOC_DEFINE(M_VNET, "vnet", "network stack control block");
86
87/*
88 * The virtual network stack list has two read-write locks, one sleepable and
89 * the other not, so that the list can be stablized and walked in a variety
90 * of network stack contexts.  Both must be acquired exclusively to modify
91 * the list, but a read lock of either lock is sufficient to walk the list.
92 */
93struct rwlock		vnet_rwlock;
94struct sx		vnet_sxlock;
95
96#define	VNET_LIST_WLOCK() do {						\
97	sx_xlock(&vnet_sxlock);						\
98	rw_wlock(&vnet_rwlock);						\
99} while (0)
100
101#define	VNET_LIST_WUNLOCK() do {					\
102	rw_wunlock(&vnet_rwlock);					\
103	sx_xunlock(&vnet_sxlock);					\
104} while (0)
105
106struct vnet_list_head vnet_head;
107struct vnet *vnet0;
108
109/*
110 * The virtual network stack allocator provides storage for virtualized
111 * global variables.  These variables are defined/declared using the
112 * VNET_DEFINE()/VNET_DECLARE() macros, which place them in the 'set_vnet'
113 * linker set.  The details of the implementation are somewhat subtle, but
114 * allow the majority of most network subsystems to maintain
115 * virtualization-agnostic.
116 *
117 * The virtual network stack allocator handles variables in the base kernel
118 * vs. modules in similar but different ways.  In both cases, virtualized
119 * global variables are marked as such by being declared to be part of the
120 * vnet linker set.  These "master" copies of global variables serve two
121 * functions:
122 *
123 * (1) They contain static initialization or "default" values for global
124 *     variables which will be propagated to each virtual network stack
125 *     instance when created.  As with normal global variables, they default
126 *     to zero-filled.
127 *
128 * (2) They act as unique global names by which the variable can be referred
129 *     to, regardless of network stack instance.  The single global symbol
130 *     will be used to calculate the location of a per-virtual instance
131 *     variable at run-time.
132 *
133 * Each virtual network stack instance has a complete copy of each
134 * virtualized global variable, stored in a malloc'd block of memory
135 * referred to by vnet->vnet_data_mem.  Critical to the design is that each
136 * per-instance memory block is laid out identically to the master block so
137 * that the offset of each global variable is the same across all blocks.  To
138 * optimize run-time access, a precalculated 'base' address,
139 * vnet->vnet_data_base, is stored in each vnet, and is the amount that can
140 * be added to the address of a 'master' instance of a variable to get to the
141 * per-vnet instance.
142 *
143 * Virtualized global variables are handled in a similar manner, but as each
144 * module has its own 'set_vnet' linker set, and we want to keep all
145 * virtualized globals togther, we reserve space in the kernel's linker set
146 * for potential module variables using a per-vnet character array,
147 * 'modspace'.  The virtual network stack allocator maintains a free list to
148 * track what space in the array is free (all, initially) and as modules are
149 * linked, allocates portions of the space to specific globals.  The kernel
150 * module linker queries the virtual network stack allocator and will
151 * bind references of the global to the location during linking.  It also
152 * calls into the virtual network stack allocator, once the memory is
153 * initialized, in order to propagate the new static initializations to all
154 * existing virtual network stack instances so that the soon-to-be executing
155 * module will find every network stack instance with proper default values.
156 */
157
158/*
159 * Number of bytes of data in the 'set_vnet' linker set, and hence the total
160 * size of all kernel virtualized global variables, and the malloc(9) type
161 * that will be used to allocate it.
162 */
163#define	VNET_BYTES	(VNET_STOP - VNET_START)
164
165static MALLOC_DEFINE(M_VNET_DATA, "vnet_data", "VNET data");
166
167/*
168 * VNET_MODMIN is the minimum number of bytes we will reserve for the sum of
169 * global variables across all loaded modules.  As this actually sizes an
170 * array declared as a virtualized global variable in the kernel itself, and
171 * we want the virtualized global variable space to be page-sized, we may
172 * have more space than that in practice.
173 */
174#define	VNET_MODMIN	(8 * PAGE_SIZE)
175#define	VNET_SIZE	roundup2(VNET_BYTES, PAGE_SIZE)
176
177/*
178 * Space to store virtualized global variables from loadable kernel modules,
179 * and the free list to manage it.
180 */
181VNET_DEFINE_STATIC(char, modspace[VNET_MODMIN] __aligned(__alignof(void *)));
182
183/*
184 * Global lists of subsystem constructor and destructors for vnets.  They are
185 * registered via VNET_SYSINIT() and VNET_SYSUNINIT().  Both lists are
186 * protected by the vnet_sysinit_sxlock global lock.
187 */
188static TAILQ_HEAD(vnet_sysinit_head, vnet_sysinit) vnet_constructors =
189	TAILQ_HEAD_INITIALIZER(vnet_constructors);
190static TAILQ_HEAD(vnet_sysuninit_head, vnet_sysinit) vnet_destructors =
191	TAILQ_HEAD_INITIALIZER(vnet_destructors);
192
193struct sx		vnet_sysinit_sxlock;
194
195#define	VNET_SYSINIT_WLOCK()	sx_xlock(&vnet_sysinit_sxlock);
196#define	VNET_SYSINIT_WUNLOCK()	sx_xunlock(&vnet_sysinit_sxlock);
197#define	VNET_SYSINIT_RLOCK()	sx_slock(&vnet_sysinit_sxlock);
198#define	VNET_SYSINIT_RUNLOCK()	sx_sunlock(&vnet_sysinit_sxlock);
199
200struct vnet_data_free {
201	uintptr_t	vnd_start;
202	int		vnd_len;
203	TAILQ_ENTRY(vnet_data_free) vnd_link;
204};
205
206static MALLOC_DEFINE(M_VNET_DATA_FREE, "vnet_data_free",
207    "VNET resource accounting");
208static TAILQ_HEAD(, vnet_data_free) vnet_data_free_head =
209	    TAILQ_HEAD_INITIALIZER(vnet_data_free_head);
210static struct sx vnet_data_free_lock;
211
212SDT_PROVIDER_DEFINE(vnet);
213SDT_PROBE_DEFINE1(vnet, functions, vnet_alloc, entry, "int");
214SDT_PROBE_DEFINE2(vnet, functions, vnet_alloc, alloc, "int",
215    "struct vnet *");
216SDT_PROBE_DEFINE2(vnet, functions, vnet_alloc, return,
217    "int", "struct vnet *");
218SDT_PROBE_DEFINE2(vnet, functions, vnet_destroy, entry,
219    "int", "struct vnet *");
220SDT_PROBE_DEFINE1(vnet, functions, vnet_destroy, return,
221    "int");
222
223#ifdef DDB
224static void db_show_vnet_print_vs(struct vnet_sysinit *, int);
225#endif
226
227/*
228 * Allocate a virtual network stack.
229 */
230struct vnet *
231vnet_alloc(void)
232{
233	struct vnet *vnet;
234
235	SDT_PROBE1(vnet, functions, vnet_alloc, entry, __LINE__);
236	vnet = malloc(sizeof(struct vnet), M_VNET, M_WAITOK | M_ZERO);
237	vnet->vnet_magic_n = VNET_MAGIC_N;
238	vnet->vnet_state = 0;
239	SDT_PROBE2(vnet, functions, vnet_alloc, alloc, __LINE__, vnet);
240
241	/*
242	 * Allocate storage for virtualized global variables and copy in
243	 * initial values form our 'master' copy.
244	 */
245	vnet->vnet_data_mem = malloc(VNET_SIZE, M_VNET_DATA, M_WAITOK);
246	memcpy(vnet->vnet_data_mem, (void *)VNET_START, VNET_BYTES);
247
248	/*
249	 * All use of vnet-specific data will immediately subtract VNET_START
250	 * from the base memory pointer, so pre-calculate that now to avoid
251	 * it on each use.
252	 */
253	vnet->vnet_data_base = (uintptr_t)vnet->vnet_data_mem - VNET_START;
254
255	/* Initialize / attach vnet module instances. */
256	CURVNET_SET_QUIET(vnet);
257	vnet_sysinit();
258	CURVNET_RESTORE();
259
260	VNET_LIST_WLOCK();
261	LIST_INSERT_HEAD(&vnet_head, vnet, vnet_le);
262	VNET_LIST_WUNLOCK();
263
264	SDT_PROBE2(vnet, functions, vnet_alloc, return, __LINE__, vnet);
265	return (vnet);
266}
267
268/*
269 * Destroy a virtual network stack.
270 */
271void
272vnet_destroy(struct vnet *vnet)
273{
274
275	SDT_PROBE2(vnet, functions, vnet_destroy, entry, __LINE__, vnet);
276	KASSERT(vnet->vnet_sockcnt == 0,
277	    ("%s: vnet still has sockets", __func__));
278
279	VNET_LIST_WLOCK();
280	LIST_REMOVE(vnet, vnet_le);
281	VNET_LIST_WUNLOCK();
282
283	CURVNET_SET_QUIET(vnet);
284	sx_xlock(&ifnet_detach_sxlock);
285	vnet_sysuninit();
286	sx_xunlock(&ifnet_detach_sxlock);
287	CURVNET_RESTORE();
288
289	/*
290	 * Release storage for the virtual network stack instance.
291	 */
292	free(vnet->vnet_data_mem, M_VNET_DATA);
293	vnet->vnet_data_mem = NULL;
294	vnet->vnet_data_base = 0;
295	vnet->vnet_magic_n = 0xdeadbeef;
296	free(vnet, M_VNET);
297	SDT_PROBE1(vnet, functions, vnet_destroy, return, __LINE__);
298}
299
300/*
301 * Boot time initialization and allocation of virtual network stacks.
302 */
303static void
304vnet_init_prelink(void *arg __unused)
305{
306
307	rw_init(&vnet_rwlock, "vnet_rwlock");
308	sx_init(&vnet_sxlock, "vnet_sxlock");
309	sx_init(&vnet_sysinit_sxlock, "vnet_sysinit_sxlock");
310	LIST_INIT(&vnet_head);
311}
312SYSINIT(vnet_init_prelink, SI_SUB_VNET_PRELINK, SI_ORDER_FIRST,
313    vnet_init_prelink, NULL);
314
315static void
316vnet0_init(void *arg __unused)
317{
318
319	if (bootverbose)
320		printf("VIMAGE (virtualized network stack) enabled\n");
321
322	/*
323	 * We MUST clear curvnet in vi_init_done() before going SMP,
324	 * otherwise CURVNET_SET() macros would scream about unnecessary
325	 * curvnet recursions.
326	 */
327	curvnet = prison0.pr_vnet = vnet0 = vnet_alloc();
328}
329SYSINIT(vnet0_init, SI_SUB_VNET, SI_ORDER_FIRST, vnet0_init, NULL);
330
331static void
332vnet_init_done(void *unused __unused)
333{
334
335	curvnet = NULL;
336}
337SYSINIT(vnet_init_done, SI_SUB_VNET_DONE, SI_ORDER_ANY, vnet_init_done,
338    NULL);
339
340/*
341 * Once on boot, initialize the modspace freelist to entirely cover modspace.
342 */
343static void
344vnet_data_startup(void *dummy __unused)
345{
346	struct vnet_data_free *df;
347
348	df = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO);
349	df->vnd_start = (uintptr_t)&VNET_NAME(modspace);
350	df->vnd_len = VNET_MODMIN;
351	TAILQ_INSERT_HEAD(&vnet_data_free_head, df, vnd_link);
352	sx_init(&vnet_data_free_lock, "vnet_data alloc lock");
353}
354SYSINIT(vnet_data, SI_SUB_KLD, SI_ORDER_FIRST, vnet_data_startup, NULL);
355
356/* Dummy VNET_SYSINIT to make sure we always reach the final end state. */
357static void
358vnet_sysinit_done(void *unused __unused)
359{
360
361	return;
362}
363VNET_SYSINIT(vnet_sysinit_done, SI_SUB_VNET_DONE, SI_ORDER_ANY,
364    vnet_sysinit_done, NULL);
365
366/*
367 * When a module is loaded and requires storage for a virtualized global
368 * variable, allocate space from the modspace free list.  This interface
369 * should be used only by the kernel linker.
370 */
371void *
372vnet_data_alloc(int size)
373{
374	struct vnet_data_free *df;
375	void *s;
376
377	s = NULL;
378	size = roundup2(size, sizeof(void *));
379	sx_xlock(&vnet_data_free_lock);
380	TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) {
381		if (df->vnd_len < size)
382			continue;
383		if (df->vnd_len == size) {
384			s = (void *)df->vnd_start;
385			TAILQ_REMOVE(&vnet_data_free_head, df, vnd_link);
386			free(df, M_VNET_DATA_FREE);
387			break;
388		}
389		s = (void *)df->vnd_start;
390		df->vnd_len -= size;
391		df->vnd_start = df->vnd_start + size;
392		break;
393	}
394	sx_xunlock(&vnet_data_free_lock);
395
396	return (s);
397}
398
399/*
400 * Free space for a virtualized global variable on module unload.
401 */
402void
403vnet_data_free(void *start_arg, int size)
404{
405	struct vnet_data_free *df;
406	struct vnet_data_free *dn;
407	uintptr_t start;
408	uintptr_t end;
409
410	size = roundup2(size, sizeof(void *));
411	start = (uintptr_t)start_arg;
412	end = start + size;
413	/*
414	 * Free a region of space and merge it with as many neighbors as
415	 * possible.  Keeping the list sorted simplifies this operation.
416	 */
417	sx_xlock(&vnet_data_free_lock);
418	TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) {
419		if (df->vnd_start > end)
420			break;
421		/*
422		 * If we expand at the end of an entry we may have to merge
423		 * it with the one following it as well.
424		 */
425		if (df->vnd_start + df->vnd_len == start) {
426			df->vnd_len += size;
427			dn = TAILQ_NEXT(df, vnd_link);
428			if (df->vnd_start + df->vnd_len == dn->vnd_start) {
429				df->vnd_len += dn->vnd_len;
430				TAILQ_REMOVE(&vnet_data_free_head, dn,
431				    vnd_link);
432				free(dn, M_VNET_DATA_FREE);
433			}
434			sx_xunlock(&vnet_data_free_lock);
435			return;
436		}
437		if (df->vnd_start == end) {
438			df->vnd_start = start;
439			df->vnd_len += size;
440			sx_xunlock(&vnet_data_free_lock);
441			return;
442		}
443	}
444	dn = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO);
445	dn->vnd_start = start;
446	dn->vnd_len = size;
447	if (df)
448		TAILQ_INSERT_BEFORE(df, dn, vnd_link);
449	else
450		TAILQ_INSERT_TAIL(&vnet_data_free_head, dn, vnd_link);
451	sx_xunlock(&vnet_data_free_lock);
452}
453
454/*
455 * When a new virtualized global variable has been allocated, propagate its
456 * initial value to each already-allocated virtual network stack instance.
457 */
458void
459vnet_data_copy(void *start, int size)
460{
461	struct vnet *vnet;
462
463	VNET_LIST_RLOCK();
464	LIST_FOREACH(vnet, &vnet_head, vnet_le)
465		memcpy((void *)((uintptr_t)vnet->vnet_data_base +
466		    (uintptr_t)start), start, size);
467	VNET_LIST_RUNLOCK();
468}
469
470/*
471 * Support for special SYSINIT handlers registered via VNET_SYSINIT()
472 * and VNET_SYSUNINIT().
473 */
474void
475vnet_register_sysinit(void *arg)
476{
477	struct vnet_sysinit *vs, *vs2;
478	struct vnet *vnet;
479
480	vs = arg;
481	KASSERT(vs->subsystem > SI_SUB_VNET, ("vnet sysinit too early"));
482
483	/* Add the constructor to the global list of vnet constructors. */
484	VNET_SYSINIT_WLOCK();
485	TAILQ_FOREACH(vs2, &vnet_constructors, link) {
486		if (vs2->subsystem > vs->subsystem)
487			break;
488		if (vs2->subsystem == vs->subsystem && vs2->order > vs->order)
489			break;
490	}
491	if (vs2 != NULL)
492		TAILQ_INSERT_BEFORE(vs2, vs, link);
493	else
494		TAILQ_INSERT_TAIL(&vnet_constructors, vs, link);
495
496	/*
497	 * Invoke the constructor on all the existing vnets when it is
498	 * registered.
499	 */
500	VNET_FOREACH(vnet) {
501		CURVNET_SET_QUIET(vnet);
502		vs->func(vs->arg);
503		CURVNET_RESTORE();
504	}
505	VNET_SYSINIT_WUNLOCK();
506}
507
508void
509vnet_deregister_sysinit(void *arg)
510{
511	struct vnet_sysinit *vs;
512
513	vs = arg;
514
515	/* Remove the constructor from the global list of vnet constructors. */
516	VNET_SYSINIT_WLOCK();
517	TAILQ_REMOVE(&vnet_constructors, vs, link);
518	VNET_SYSINIT_WUNLOCK();
519}
520
521void
522vnet_register_sysuninit(void *arg)
523{
524	struct vnet_sysinit *vs, *vs2;
525
526	vs = arg;
527
528	/* Add the destructor to the global list of vnet destructors. */
529	VNET_SYSINIT_WLOCK();
530	TAILQ_FOREACH(vs2, &vnet_destructors, link) {
531		if (vs2->subsystem > vs->subsystem)
532			break;
533		if (vs2->subsystem == vs->subsystem && vs2->order > vs->order)
534			break;
535	}
536	if (vs2 != NULL)
537		TAILQ_INSERT_BEFORE(vs2, vs, link);
538	else
539		TAILQ_INSERT_TAIL(&vnet_destructors, vs, link);
540	VNET_SYSINIT_WUNLOCK();
541}
542
543void
544vnet_deregister_sysuninit(void *arg)
545{
546	struct vnet_sysinit *vs;
547	struct vnet *vnet;
548
549	vs = arg;
550
551	/*
552	 * Invoke the destructor on all the existing vnets when it is
553	 * deregistered.
554	 */
555	VNET_SYSINIT_WLOCK();
556	VNET_FOREACH(vnet) {
557		CURVNET_SET_QUIET(vnet);
558		vs->func(vs->arg);
559		CURVNET_RESTORE();
560	}
561
562	/* Remove the destructor from the global list of vnet destructors. */
563	TAILQ_REMOVE(&vnet_destructors, vs, link);
564	VNET_SYSINIT_WUNLOCK();
565}
566
567/*
568 * Invoke all registered vnet constructors on the current vnet.  Used during
569 * vnet construction.  The caller is responsible for ensuring the new vnet is
570 * the current vnet and that the vnet_sysinit_sxlock lock is locked.
571 */
572void
573vnet_sysinit(void)
574{
575	struct vnet_sysinit *vs;
576
577	VNET_SYSINIT_RLOCK();
578	TAILQ_FOREACH(vs, &vnet_constructors, link) {
579		curvnet->vnet_state = vs->subsystem;
580		vs->func(vs->arg);
581	}
582	VNET_SYSINIT_RUNLOCK();
583}
584
585/*
586 * Invoke all registered vnet destructors on the current vnet.  Used during
587 * vnet destruction.  The caller is responsible for ensuring the dying vnet
588 * the current vnet and that the vnet_sysinit_sxlock lock is locked.
589 */
590void
591vnet_sysuninit(void)
592{
593	struct vnet_sysinit *vs;
594
595	VNET_SYSINIT_RLOCK();
596	TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head,
597	    link) {
598		curvnet->vnet_state = vs->subsystem;
599		vs->func(vs->arg);
600	}
601	VNET_SYSINIT_RUNLOCK();
602}
603
604/*
605 * EVENTHANDLER(9) extensions.
606 */
607/*
608 * Invoke the eventhandler function originally registered with the possibly
609 * registered argument for all virtual network stack instances.
610 *
611 * This iterator can only be used for eventhandlers that do not take any
612 * additional arguments, as we do ignore the variadic arguments from the
613 * EVENTHANDLER_INVOKE() call.
614 */
615void
616vnet_global_eventhandler_iterator_func(void *arg, ...)
617{
618	VNET_ITERATOR_DECL(vnet_iter);
619	struct eventhandler_entry_vimage *v_ee;
620
621	/*
622	 * There is a bug here in that we should actually cast things to
623	 * (struct eventhandler_entry_ ## name *)  but that's not easily
624	 * possible in here so just re-using the variadic version we
625	 * defined for the generic vimage case.
626	 */
627	v_ee = arg;
628	VNET_LIST_RLOCK();
629	VNET_FOREACH(vnet_iter) {
630		CURVNET_SET(vnet_iter);
631		((vimage_iterator_func_t)v_ee->func)(v_ee->ee_arg);
632		CURVNET_RESTORE();
633	}
634	VNET_LIST_RUNLOCK();
635}
636
637#ifdef VNET_DEBUG
638struct vnet_recursion {
639	SLIST_ENTRY(vnet_recursion)	 vnr_le;
640	const char			*prev_fn;
641	const char			*where_fn;
642	int				 where_line;
643	struct vnet			*old_vnet;
644	struct vnet			*new_vnet;
645};
646
647static SLIST_HEAD(, vnet_recursion) vnet_recursions =
648    SLIST_HEAD_INITIALIZER(vnet_recursions);
649
650static void
651vnet_print_recursion(struct vnet_recursion *vnr, int brief)
652{
653
654	if (!brief)
655		printf("CURVNET_SET() recursion in ");
656	printf("%s() line %d, prev in %s()", vnr->where_fn, vnr->where_line,
657	    vnr->prev_fn);
658	if (brief)
659		printf(", ");
660	else
661		printf("\n    ");
662	printf("%p -> %p\n", vnr->old_vnet, vnr->new_vnet);
663}
664
665void
666vnet_log_recursion(struct vnet *old_vnet, const char *old_fn, int line)
667{
668	struct vnet_recursion *vnr;
669
670	/* Skip already logged recursion events. */
671	SLIST_FOREACH(vnr, &vnet_recursions, vnr_le)
672		if (vnr->prev_fn == old_fn &&
673		    vnr->where_fn == curthread->td_vnet_lpush &&
674		    vnr->where_line == line &&
675		    (vnr->old_vnet == vnr->new_vnet) == (curvnet == old_vnet))
676			return;
677
678	vnr = malloc(sizeof(*vnr), M_VNET, M_NOWAIT | M_ZERO);
679	if (vnr == NULL)
680		panic("%s: malloc failed", __func__);
681	vnr->prev_fn = old_fn;
682	vnr->where_fn = curthread->td_vnet_lpush;
683	vnr->where_line = line;
684	vnr->old_vnet = old_vnet;
685	vnr->new_vnet = curvnet;
686
687	SLIST_INSERT_HEAD(&vnet_recursions, vnr, vnr_le);
688
689	vnet_print_recursion(vnr, 0);
690#ifdef KDB
691	kdb_backtrace();
692#endif
693}
694#endif /* VNET_DEBUG */
695
696/*
697 * DDB(4).
698 */
699#ifdef DDB
700static void
701db_vnet_print(struct vnet *vnet)
702{
703
704	db_printf("vnet            = %p\n", vnet);
705	db_printf(" vnet_magic_n   = %#08x (%s, orig %#08x)\n",
706	    vnet->vnet_magic_n,
707	    (vnet->vnet_magic_n == VNET_MAGIC_N) ?
708		"ok" : "mismatch", VNET_MAGIC_N);
709	db_printf(" vnet_ifcnt     = %u\n", vnet->vnet_ifcnt);
710	db_printf(" vnet_sockcnt   = %u\n", vnet->vnet_sockcnt);
711	db_printf(" vnet_data_mem  = %p\n", vnet->vnet_data_mem);
712	db_printf(" vnet_data_base = %#jx\n",
713	    (uintmax_t)vnet->vnet_data_base);
714	db_printf(" vnet_state     = %#08x\n", vnet->vnet_state);
715	db_printf("\n");
716}
717
718DB_SHOW_ALL_COMMAND(vnets, db_show_all_vnets)
719{
720	VNET_ITERATOR_DECL(vnet_iter);
721
722	VNET_FOREACH(vnet_iter) {
723		db_vnet_print(vnet_iter);
724		if (db_pager_quit)
725			break;
726	}
727}
728
729DB_SHOW_COMMAND(vnet, db_show_vnet)
730{
731
732	if (!have_addr) {
733		db_printf("usage: show vnet <struct vnet *>\n");
734		return;
735	}
736
737	db_vnet_print((struct vnet *)addr);
738}
739
740static void
741db_show_vnet_print_vs(struct vnet_sysinit *vs, int ddb)
742{
743	const char *vsname, *funcname;
744	c_db_sym_t sym;
745	db_expr_t  offset;
746
747#define xprint(...)							\
748	if (ddb)							\
749		db_printf(__VA_ARGS__);					\
750	else								\
751		printf(__VA_ARGS__)
752
753	if (vs == NULL) {
754		xprint("%s: no vnet_sysinit * given\n", __func__);
755		return;
756	}
757
758	sym = db_search_symbol((vm_offset_t)vs, DB_STGY_ANY, &offset);
759	db_symbol_values(sym, &vsname, NULL);
760	sym = db_search_symbol((vm_offset_t)vs->func, DB_STGY_PROC, &offset);
761	db_symbol_values(sym, &funcname, NULL);
762	xprint("%s(%p)\n", (vsname != NULL) ? vsname : "", vs);
763	xprint("  %#08x %#08x\n", vs->subsystem, vs->order);
764	xprint("  %p(%s)(%p)\n",
765	    vs->func, (funcname != NULL) ? funcname : "", vs->arg);
766#undef xprint
767}
768
769DB_SHOW_COMMAND(vnet_sysinit, db_show_vnet_sysinit)
770{
771	struct vnet_sysinit *vs;
772
773	db_printf("VNET_SYSINIT vs Name(Ptr)\n");
774	db_printf("  Subsystem  Order\n");
775	db_printf("  Function(Name)(Arg)\n");
776	TAILQ_FOREACH(vs, &vnet_constructors, link) {
777		db_show_vnet_print_vs(vs, 1);
778		if (db_pager_quit)
779			break;
780	}
781}
782
783DB_SHOW_COMMAND(vnet_sysuninit, db_show_vnet_sysuninit)
784{
785	struct vnet_sysinit *vs;
786
787	db_printf("VNET_SYSUNINIT vs Name(Ptr)\n");
788	db_printf("  Subsystem  Order\n");
789	db_printf("  Function(Name)(Arg)\n");
790	TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head,
791	    link) {
792		db_show_vnet_print_vs(vs, 1);
793		if (db_pager_quit)
794			break;
795	}
796}
797
798#ifdef VNET_DEBUG
799DB_SHOW_COMMAND(vnetrcrs, db_show_vnetrcrs)
800{
801	struct vnet_recursion *vnr;
802
803	SLIST_FOREACH(vnr, &vnet_recursions, vnr_le)
804		vnet_print_recursion(vnr, 1);
805}
806#endif
807#endif /* DDB */
808