2 * Copyright (c) 2004-2009 University of Zagreb
3 * Copyright (c) 2006-2009 FreeBSD Foundation
6 * This software was developed by the University of Zagreb and the
7 * FreeBSD Foundation under sponsorship by the Stichting NLnet and the
10 * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
11 * Copyright (c) 2009 Robert N. M. Watson
12 * All rights reserved.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
41 #include "opt_kdtrace.h"
43 #include <sys/param.h>
45 #include <sys/kernel.h>
48 #include <sys/systm.h>
49 #include <sys/sysctl.h>
50 #include <sys/linker_set.h>
52 #include <sys/malloc.h>
54 #include <sys/socket.h>
56 #include <sys/sysctl.h>
60 #include <ddb/db_sym.h>
64 #include <net/if_var.h>
68 * This file implements core functions for virtual network stacks:
70 * - Virtual network stack management functions.
72 * - Virtual network stack memory allocator, which virtualizes global
73 * variables in the network stack
75 * - Virtualized SYSINIT's/SYSUNINIT's, which allow network stack subsystems
76 * to register startup/shutdown events to be run for each virtual network
80 MALLOC_DEFINE(M_VNET, "vnet", "network stack control block");
83 * The virtual network stack list has two read-write locks, one sleepable and
84 * the other not, so that the list can be stablized and walked in a variety
85 * of network stack contexts. Both must be acquired exclusively to modify
86 * the list, but a read lock of either lock is sufficient to walk the list.
88 struct rwlock vnet_rwlock;
89 struct sx vnet_sxlock;
91 #define VNET_LIST_WLOCK() do { \
92 sx_xlock(&vnet_sxlock); \
93 rw_wlock(&vnet_rwlock); \
96 #define VNET_LIST_WUNLOCK() do { \
97 rw_wunlock(&vnet_rwlock); \
98 sx_xunlock(&vnet_sxlock); \
101 struct vnet_list_head vnet_head;
105 * The virtual network stack allocator provides storage for virtualized
106 * global variables. These variables are defined/declared using the
107 * VNET_DEFINE()/VNET_DECLARE() macros, which place them in the 'set_vnet'
108 * linker set. The details of the implementation are somewhat subtle, but
109 * allow the majority of most network subsystems to maintain
110 * virtualization-agnostic.
112 * The virtual network stack allocator handles variables in the base kernel
113 * vs. modules in similar but different ways. In both cases, virtualized
114 * global variables are marked as such by being declared to be part of the
115 * vnet linker set. These "master" copies of global variables serve two
118 * (1) They contain static initialization or "default" values for global
119 * variables which will be propagated to each virtual network stack
120 * instance when created. As with normal global variables, they default
123 * (2) They act as unique global names by which the variable can be referred
124 * to, regardless of network stack instance. The single global symbol
125 * will be used to calculate the location of a per-virtual instance
126 * variable at run-time.
128 * Each virtual network stack instance has a complete copy of each
129 * virtualized global variable, stored in a malloc'd block of memory
130 * referred to by vnet->vnet_data_mem. Critical to the design is that each
131 * per-instance memory block is laid out identically to the master block so
132 * that the offset of each global variable is the same across all blocks. To
133 * optimize run-time access, a precalculated 'base' address,
134 * vnet->vnet_data_base, is stored in each vnet, and is the amount that can
135 * be added to the address of a 'master' instance of a variable to get to the
138 * Virtualized global variables are handled in a similar manner, but as each
139 * module has its own 'set_vnet' linker set, and we want to keep all
140 * virtualized globals togther, we reserve space in the kernel's linker set
141 * for potential module variables using a per-vnet character array,
142 * 'modspace'. The virtual network stack allocator maintains a free list to
143 * track what space in the array is free (all, initially) and as modules are
144 * linked, allocates portions of the space to specific globals. The kernel
145 * module linker queries the virtual network stack allocator and will
146 * bind references of the global to the location during linking. It also
147 * calls into the virtual network stack allocator, once the memory is
148 * initialized, in order to propagate the new static initializations to all
149 * existing virtual network stack instances so that the soon-to-be executing
150 * module will find every network stack instance with proper default values.
154 * Location of the kernel's 'set_vnet' linker set.
156 extern uintptr_t *__start_set_vnet;
157 extern uintptr_t *__stop_set_vnet;
159 #define VNET_START (uintptr_t)&__start_set_vnet
160 #define VNET_STOP (uintptr_t)&__stop_set_vnet
163 * Number of bytes of data in the 'set_vnet' linker set, and hence the total
164 * size of all kernel virtualized global variables, and the malloc(9) type
165 * that will be used to allocate it.
167 #define VNET_BYTES (VNET_STOP - VNET_START)
169 MALLOC_DEFINE(M_VNET_DATA, "vnet_data", "VNET data");
172 * VNET_MODMIN is the minimum number of bytes we will reserve for the sum of
173 * global variables across all loaded modules. As this actually sizes an
174 * array declared as a virtualized global variable in the kernel itself, and
175 * we want the virtualized global variable space to be page-sized, we may
176 * have more space than that in practice.
178 #define VNET_MODMIN 8192
179 #define VNET_SIZE roundup2(VNET_BYTES, PAGE_SIZE)
180 #define VNET_MODSIZE (VNET_SIZE - (VNET_BYTES - VNET_MODMIN))
183 * Space to store virtualized global variables from loadable kernel modules,
184 * and the free list to manage it.
186 static VNET_DEFINE(char, modspace[VNET_MODMIN]);
189 * Global lists of subsystem constructor and destructors for vnets. They are
190 * registered via VNET_SYSINIT() and VNET_SYSUNINIT(). Both lists are
191 * protected by the vnet_sysinit_sxlock global lock.
193 static TAILQ_HEAD(vnet_sysinit_head, vnet_sysinit) vnet_constructors =
194 TAILQ_HEAD_INITIALIZER(vnet_constructors);
195 static TAILQ_HEAD(vnet_sysuninit_head, vnet_sysinit) vnet_destructors =
196 TAILQ_HEAD_INITIALIZER(vnet_destructors);
198 struct sx vnet_sysinit_sxlock;
200 #define VNET_SYSINIT_WLOCK() sx_xlock(&vnet_sysinit_sxlock);
201 #define VNET_SYSINIT_WUNLOCK() sx_xunlock(&vnet_sysinit_sxlock);
202 #define VNET_SYSINIT_RLOCK() sx_slock(&vnet_sysinit_sxlock);
203 #define VNET_SYSINIT_RUNLOCK() sx_sunlock(&vnet_sysinit_sxlock);
205 struct vnet_data_free {
208 TAILQ_ENTRY(vnet_data_free) vnd_link;
211 MALLOC_DEFINE(M_VNET_DATA_FREE, "vnet_data_free", "VNET resource accounting");
212 static TAILQ_HEAD(, vnet_data_free) vnet_data_free_head =
213 TAILQ_HEAD_INITIALIZER(vnet_data_free_head);
214 static struct sx vnet_data_free_lock;
216 SDT_PROVIDER_DEFINE(vnet);
217 SDT_PROBE_DEFINE1(vnet, functions, vnet_alloc, entry, "int");
218 SDT_PROBE_DEFINE2(vnet, functions, vnet_alloc, alloc, "int", "struct vnet *");
219 SDT_PROBE_DEFINE2(vnet, functions, vnet_alloc, return, "int", "struct vnet *");
220 SDT_PROBE_DEFINE2(vnet, functions, vnet_destroy, entry, "int", "struct vnet *");
221 SDT_PROBE_DEFINE1(vnet, functions, vnet_destroy, return, "int");
224 static void db_show_vnet_print_vs(struct vnet_sysinit *, int);
228 * Allocate a virtual network stack.
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 SDT_PROBE2(vnet, functions, vnet_alloc, alloc, __LINE__, vnet);
241 * Allocate storage for virtualized global variables and copy in
242 * initial values form our 'master' copy.
244 vnet->vnet_data_mem = malloc(VNET_SIZE, M_VNET_DATA, M_WAITOK);
245 memcpy(vnet->vnet_data_mem, (void *)VNET_START, VNET_BYTES);
248 * All use of vnet-specific data will immediately subtract VNET_START
249 * from the base memory pointer, so pre-calculate that now to avoid
252 vnet->vnet_data_base = (uintptr_t)vnet->vnet_data_mem - VNET_START;
254 /* Initialize / attach vnet module instances. */
255 CURVNET_SET_QUIET(vnet);
260 LIST_INSERT_HEAD(&vnet_head, vnet, vnet_le);
263 SDT_PROBE2(vnet, functions, vnet_alloc, return, __LINE__, vnet);
268 * Destroy a virtual network stack.
271 vnet_destroy(struct vnet *vnet)
273 struct ifnet *ifp, *nifp;
275 SDT_PROBE2(vnet, functions, vnet_destroy, entry, __LINE__, vnet);
276 KASSERT(vnet->vnet_sockcnt == 0,
277 ("%s: vnet still has sockets", __func__));
280 LIST_REMOVE(vnet, vnet_le);
283 CURVNET_SET_QUIET(vnet);
285 /* Return all inherited interfaces to their parent vnets. */
286 TAILQ_FOREACH_SAFE(ifp, &V_ifnet, if_link, nifp) {
287 if (ifp->if_home_vnet != ifp->if_vnet)
288 if_vmove(ifp, ifp->if_home_vnet);
295 * Release storage for the virtual network stack instance.
297 free(vnet->vnet_data_mem, M_VNET_DATA);
298 vnet->vnet_data_mem = NULL;
299 vnet->vnet_data_base = 0;
300 vnet->vnet_magic_n = 0xdeadbeef;
302 SDT_PROBE1(vnet, functions, vnet_destroy, return, __LINE__);
306 * Boot time initialization and allocation of virtual network stacks.
309 vnet_init_prelink(void *arg)
312 rw_init(&vnet_rwlock, "vnet_rwlock");
313 sx_init(&vnet_sxlock, "vnet_sxlock");
314 sx_init(&vnet_sysinit_sxlock, "vnet_sysinit_sxlock");
315 LIST_INIT(&vnet_head);
317 SYSINIT(vnet_init_prelink, SI_SUB_VNET_PRELINK, SI_ORDER_FIRST,
318 vnet_init_prelink, NULL);
321 vnet0_init(void *arg)
324 /* Warn people before take off - in case we crash early. */
325 printf("WARNING: VIMAGE (virtualized network stack) is a highly "
326 "experimental feature.\n");
329 * We MUST clear curvnet in vi_init_done() before going SMP,
330 * otherwise CURVNET_SET() macros would scream about unnecessary
331 * curvnet recursions.
333 curvnet = prison0.pr_vnet = vnet0 = vnet_alloc();
335 SYSINIT(vnet0_init, SI_SUB_VNET, SI_ORDER_FIRST, vnet0_init, NULL);
338 vnet_init_done(void *unused)
344 SYSINIT(vnet_init_done, SI_SUB_VNET_DONE, SI_ORDER_FIRST, vnet_init_done,
348 * Once on boot, initialize the modspace freelist to entirely cover modspace.
351 vnet_data_startup(void *dummy __unused)
353 struct vnet_data_free *df;
355 df = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO);
356 df->vnd_start = (uintptr_t)&VNET_NAME(modspace);
357 df->vnd_len = VNET_MODSIZE;
358 TAILQ_INSERT_HEAD(&vnet_data_free_head, df, vnd_link);
359 sx_init(&vnet_data_free_lock, "vnet_data alloc lock");
361 SYSINIT(vnet_data, SI_SUB_KLD, SI_ORDER_FIRST, vnet_data_startup, 0);
364 * When a module is loaded and requires storage for a virtualized global
365 * variable, allocate space from the modspace free list. This interface
366 * should be used only by the kernel linker.
369 vnet_data_alloc(int size)
371 struct vnet_data_free *df;
375 size = roundup2(size, sizeof(void *));
376 sx_xlock(&vnet_data_free_lock);
377 TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) {
378 if (df->vnd_len < size)
380 if (df->vnd_len == size) {
381 s = (void *)df->vnd_start;
382 TAILQ_REMOVE(&vnet_data_free_head, df, vnd_link);
383 free(df, M_VNET_DATA_FREE);
386 s = (void *)df->vnd_start;
388 df->vnd_start = df->vnd_start + size;
391 sx_xunlock(&vnet_data_free_lock);
397 * Free space for a virtualized global variable on module unload.
400 vnet_data_free(void *start_arg, int size)
402 struct vnet_data_free *df;
403 struct vnet_data_free *dn;
407 size = roundup2(size, sizeof(void *));
408 start = (uintptr_t)start_arg;
411 * Free a region of space and merge it with as many neighbors as
412 * possible. Keeping the list sorted simplifies this operation.
414 sx_xlock(&vnet_data_free_lock);
415 TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) {
416 if (df->vnd_start > end)
419 * If we expand at the end of an entry we may have to merge
420 * it with the one following it as well.
422 if (df->vnd_start + df->vnd_len == start) {
424 dn = TAILQ_NEXT(df, vnd_link);
425 if (df->vnd_start + df->vnd_len == dn->vnd_start) {
426 df->vnd_len += dn->vnd_len;
427 TAILQ_REMOVE(&vnet_data_free_head, dn,
429 free(dn, M_VNET_DATA_FREE);
431 sx_xunlock(&vnet_data_free_lock);
434 if (df->vnd_start == end) {
435 df->vnd_start = start;
437 sx_xunlock(&vnet_data_free_lock);
441 dn = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO);
442 dn->vnd_start = start;
445 TAILQ_INSERT_BEFORE(df, dn, vnd_link);
447 TAILQ_INSERT_TAIL(&vnet_data_free_head, dn, vnd_link);
448 sx_xunlock(&vnet_data_free_lock);
452 * When a new virtualized global variable has been allocated, propagate its
453 * initial value to each already-allocated virtual network stack instance.
456 vnet_data_copy(void *start, int size)
461 LIST_FOREACH(vnet, &vnet_head, vnet_le)
462 memcpy((void *)((uintptr_t)vnet->vnet_data_base +
463 (uintptr_t)start), start, size);
468 * Variants on sysctl_handle_foo that know how to handle virtualized global
469 * variables: if 'arg1' is a pointer, then we transform it to the local vnet
473 vnet_sysctl_handle_int(SYSCTL_HANDLER_ARGS)
477 arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
478 return (sysctl_handle_int(oidp, arg1, arg2, req));
482 vnet_sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
486 arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
487 return (sysctl_handle_opaque(oidp, arg1, arg2, req));
491 vnet_sysctl_handle_string(SYSCTL_HANDLER_ARGS)
495 arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
496 return (sysctl_handle_string(oidp, arg1, arg2, req));
500 vnet_sysctl_handle_uint(SYSCTL_HANDLER_ARGS)
504 arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
505 return (sysctl_handle_int(oidp, arg1, arg2, req));
509 * Support for special SYSINIT handlers registered via VNET_SYSINIT()
510 * and VNET_SYSUNINIT().
513 vnet_register_sysinit(void *arg)
515 struct vnet_sysinit *vs, *vs2;
519 KASSERT(vs->subsystem > SI_SUB_VNET, ("vnet sysinit too early"));
521 /* Add the constructor to the global list of vnet constructors. */
522 VNET_SYSINIT_WLOCK();
523 TAILQ_FOREACH(vs2, &vnet_constructors, link) {
524 if (vs2->subsystem > vs->subsystem)
526 if (vs2->subsystem == vs->subsystem && vs2->order > vs->order)
530 TAILQ_INSERT_BEFORE(vs2, vs, link);
532 TAILQ_INSERT_TAIL(&vnet_constructors, vs, link);
535 * Invoke the constructor on all the existing vnets when it is
539 CURVNET_SET_QUIET(vnet);
543 VNET_SYSINIT_WUNLOCK();
547 vnet_deregister_sysinit(void *arg)
549 struct vnet_sysinit *vs;
553 /* Remove the constructor from the global list of vnet constructors. */
554 VNET_SYSINIT_WLOCK();
555 TAILQ_REMOVE(&vnet_constructors, vs, link);
556 VNET_SYSINIT_WUNLOCK();
560 vnet_register_sysuninit(void *arg)
562 struct vnet_sysinit *vs, *vs2;
566 /* Add the destructor to the global list of vnet destructors. */
567 VNET_SYSINIT_WLOCK();
568 TAILQ_FOREACH(vs2, &vnet_destructors, link) {
569 if (vs2->subsystem > vs->subsystem)
571 if (vs2->subsystem == vs->subsystem && vs2->order > vs->order)
575 TAILQ_INSERT_BEFORE(vs2, vs, link);
577 TAILQ_INSERT_TAIL(&vnet_destructors, vs, link);
578 VNET_SYSINIT_WUNLOCK();
582 vnet_deregister_sysuninit(void *arg)
584 struct vnet_sysinit *vs;
590 * Invoke the destructor on all the existing vnets when it is
593 VNET_SYSINIT_WLOCK();
595 CURVNET_SET_QUIET(vnet);
600 /* Remove the destructor from the global list of vnet destructors. */
601 TAILQ_REMOVE(&vnet_destructors, vs, link);
602 VNET_SYSINIT_WUNLOCK();
606 * Invoke all registered vnet constructors on the current vnet. Used during
607 * vnet construction. The caller is responsible for ensuring the new vnet is
608 * the current vnet and that the vnet_sysinit_sxlock lock is locked.
613 struct vnet_sysinit *vs;
615 VNET_SYSINIT_RLOCK();
616 TAILQ_FOREACH(vs, &vnet_constructors, link) {
619 VNET_SYSINIT_RUNLOCK();
623 * Invoke all registered vnet destructors on the current vnet. Used during
624 * vnet destruction. The caller is responsible for ensuring the dying vnet
625 * the current vnet and that the vnet_sysinit_sxlock lock is locked.
630 struct vnet_sysinit *vs;
632 VNET_SYSINIT_RLOCK();
633 TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head,
637 VNET_SYSINIT_RUNLOCK();
641 struct vnet_recursion {
642 SLIST_ENTRY(vnet_recursion) vnr_le;
644 const char *where_fn;
646 struct vnet *old_vnet;
647 struct vnet *new_vnet;
650 static SLIST_HEAD(, vnet_recursion) vnet_recursions =
651 SLIST_HEAD_INITIALIZER(vnet_recursions);
654 vnet_print_recursion(struct vnet_recursion *vnr, int brief)
658 printf("CURVNET_SET() recursion in ");
659 printf("%s() line %d, prev in %s()", vnr->where_fn, vnr->where_line,
665 printf("%p -> %p\n", vnr->old_vnet, vnr->new_vnet);
669 vnet_log_recursion(struct vnet *old_vnet, const char *old_fn, int line)
671 struct vnet_recursion *vnr;
673 /* Skip already logged recursion events. */
674 SLIST_FOREACH(vnr, &vnet_recursions, vnr_le)
675 if (vnr->prev_fn == old_fn &&
676 vnr->where_fn == curthread->td_vnet_lpush &&
677 vnr->where_line == line &&
678 (vnr->old_vnet == vnr->new_vnet) == (curvnet == old_vnet))
681 vnr = malloc(sizeof(*vnr), M_VNET, M_NOWAIT | M_ZERO);
683 panic("%s: malloc failed", __func__);
684 vnr->prev_fn = old_fn;
685 vnr->where_fn = curthread->td_vnet_lpush;
686 vnr->where_line = line;
687 vnr->old_vnet = old_vnet;
688 vnr->new_vnet = curvnet;
690 SLIST_INSERT_HEAD(&vnet_recursions, vnr, vnr_le);
692 vnet_print_recursion(vnr, 0);
697 #endif /* VNET_DEBUG */
700 DB_SHOW_COMMAND(vnets, db_show_vnets)
702 VNET_ITERATOR_DECL(vnet_iter);
704 VNET_FOREACH(vnet_iter) {
705 db_printf("vnet = %p\n", vnet_iter);
706 db_printf(" vnet_magic_n = 0x%x (%s, orig 0x%x)\n",
707 vnet_iter->vnet_magic_n,
708 (vnet_iter->vnet_magic_n == VNET_MAGIC_N) ?
709 "ok" : "mismatch", VNET_MAGIC_N);
710 db_printf(" vnet_ifcnt = %u\n", vnet_iter->vnet_ifcnt);
711 db_printf(" vnet_sockcnt = %u\n", vnet_iter->vnet_sockcnt);
712 db_printf(" vnet_data_mem = %p\n", vnet_iter->vnet_data_mem);
713 db_printf(" vnet_data_base = 0x%jx\n",
714 (uintmax_t)vnet_iter->vnet_data_base);
722 db_show_vnet_print_vs(struct vnet_sysinit *vs, int ddb)
724 const char *vsname, *funcname;
728 #define xprint(...) \
730 db_printf(__VA_ARGS__); \
735 xprint("%s: no vnet_sysinit * given\n", __func__);
739 sym = db_search_symbol((vm_offset_t)vs, DB_STGY_ANY, &offset);
740 db_symbol_values(sym, &vsname, NULL);
741 sym = db_search_symbol((vm_offset_t)vs->func, DB_STGY_PROC, &offset);
742 db_symbol_values(sym, &funcname, NULL);
743 xprint("%s(%p)\n", (vsname != NULL) ? vsname : "", vs);
744 xprint(" 0x%08x 0x%08x\n", vs->subsystem, vs->order);
745 xprint(" %p(%s)(%p)\n",
746 vs->func, (funcname != NULL) ? funcname : "", vs->arg);
750 DB_SHOW_COMMAND(vnet_sysinit, db_show_vnet_sysinit)
752 struct vnet_sysinit *vs;
754 db_printf("VNET_SYSINIT vs Name(Ptr)\n");
755 db_printf(" Subsystem Order\n");
756 db_printf(" Function(Name)(Arg)\n");
757 TAILQ_FOREACH(vs, &vnet_constructors, link) {
758 db_show_vnet_print_vs(vs, 1);
764 DB_SHOW_COMMAND(vnet_sysuninit, db_show_vnet_sysuninit)
766 struct vnet_sysinit *vs;
768 db_printf("VNET_SYSUNINIT vs Name(Ptr)\n");
769 db_printf(" Subsystem Order\n");
770 db_printf(" Function(Name)(Arg)\n");
771 TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head,
773 db_show_vnet_print_vs(vs, 1);
780 DB_SHOW_COMMAND(vnetrcrs, db_show_vnetrcrs)
782 struct vnet_recursion *vnr;
784 SLIST_FOREACH(vnr, &vnet_recursions, vnr_le)
785 vnet_print_recursion(vnr, 1);