/*- * Copyright (c) 2004-2009 University of Zagreb * Copyright (c) 2006-2009 FreeBSD Foundation * All rights reserved. * * This software was developed by the University of Zagreb and the * FreeBSD Foundation under sponsorship by the Stichting NLnet and the * FreeBSD Foundation. * * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org> * Copyright (c) 2009 Robert N. M. Watson * All rights reserved. * * 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 "opt_ddb.h" #include "opt_kdb.h" #include <sys/param.h> #include <sys/kdb.h> #include <sys/kernel.h> #include <sys/jail.h> #include <sys/sdt.h> #include <sys/systm.h> #include <sys/sysctl.h> #include <sys/eventhandler.h> #include <sys/lock.h> #include <sys/malloc.h> #include <sys/proc.h> #include <sys/socket.h> #include <sys/sx.h> #include <sys/sysctl.h> #include <machine/stdarg.h> #ifdef DDB #include <ddb/ddb.h> #include <ddb/db_sym.h> #endif #include <net/if.h> #include <net/if_var.h> #include <net/vnet.h> /*- * This file implements core functions for virtual network stacks: * * - Virtual network stack management functions. * * - Virtual network stack memory allocator, which virtualizes global * variables in the network stack * * - Virtualized SYSINIT's/SYSUNINIT's, which allow network stack subsystems * to register startup/shutdown events to be run for each virtual network * stack instance. */ FEATURE(vimage, "VIMAGE kernel virtualization"); static MALLOC_DEFINE(M_VNET, "vnet", "network stack control block"); /* * The virtual network stack list has two read-write locks, one sleepable and * the other not, so that the list can be stablized and walked in a variety * of network stack contexts. Both must be acquired exclusively to modify * the list, but a read lock of either lock is sufficient to walk the list. */ struct rwlock vnet_rwlock; struct sx vnet_sxlock; #define VNET_LIST_WLOCK() do { \ sx_xlock(&vnet_sxlock); \ rw_wlock(&vnet_rwlock); \ } while (0) #define VNET_LIST_WUNLOCK() do { \ rw_wunlock(&vnet_rwlock); \ sx_xunlock(&vnet_sxlock); \ } while (0) struct vnet_list_head vnet_head; struct vnet *vnet0; /* * The virtual network stack allocator provides storage for virtualized * global variables. These variables are defined/declared using the * VNET_DEFINE()/VNET_DECLARE() macros, which place them in the 'set_vnet' * linker set. The details of the implementation are somewhat subtle, but * allow the majority of most network subsystems to maintain * virtualization-agnostic. * * The virtual network stack allocator handles variables in the base kernel * vs. modules in similar but different ways. In both cases, virtualized * global variables are marked as such by being declared to be part of the * vnet linker set. These "master" copies of global variables serve two * functions: * * (1) They contain static initialization or "default" values for global * variables which will be propagated to each virtual network stack * instance when created. As with normal global variables, they default * to zero-filled. * * (2) They act as unique global names by which the variable can be referred * to, regardless of network stack instance. The single global symbol * will be used to calculate the location of a per-virtual instance * variable at run-time. * * Each virtual network stack instance has a complete copy of each * virtualized global variable, stored in a malloc'd block of memory * referred to by vnet->vnet_data_mem. Critical to the design is that each * per-instance memory block is laid out identically to the master block so * that the offset of each global variable is the same across all blocks. To * optimize run-time access, a precalculated 'base' address, * vnet->vnet_data_base, is stored in each vnet, and is the amount that can * be added to the address of a 'master' instance of a variable to get to the * per-vnet instance. * * Virtualized global variables are handled in a similar manner, but as each * module has its own 'set_vnet' linker set, and we want to keep all * virtualized globals togther, we reserve space in the kernel's linker set * for potential module variables using a per-vnet character array, * 'modspace'. The virtual network stack allocator maintains a free list to * track what space in the array is free (all, initially) and as modules are * linked, allocates portions of the space to specific globals. The kernel * module linker queries the virtual network stack allocator and will * bind references of the global to the location during linking. It also * calls into the virtual network stack allocator, once the memory is * initialized, in order to propagate the new static initializations to all * existing virtual network stack instances so that the soon-to-be executing * module will find every network stack instance with proper default values. */ /* * Number of bytes of data in the 'set_vnet' linker set, and hence the total * size of all kernel virtualized global variables, and the malloc(9) type * that will be used to allocate it. */ #define VNET_BYTES (VNET_STOP - VNET_START) static MALLOC_DEFINE(M_VNET_DATA, "vnet_data", "VNET data"); /* * VNET_MODMIN is the minimum number of bytes we will reserve for the sum of * global variables across all loaded modules. As this actually sizes an * array declared as a virtualized global variable in the kernel itself, and * we want the virtualized global variable space to be page-sized, we may * have more space than that in practice. */ #define VNET_MODMIN 8192 #define VNET_SIZE roundup2(VNET_BYTES, PAGE_SIZE) #define VNET_MODSIZE (VNET_SIZE - (VNET_BYTES - VNET_MODMIN)) /* * Space to store virtualized global variables from loadable kernel modules, * and the free list to manage it. */ static VNET_DEFINE(char, modspace[VNET_MODMIN]); /* * Global lists of subsystem constructor and destructors for vnets. They are * registered via VNET_SYSINIT() and VNET_SYSUNINIT(). Both lists are * protected by the vnet_sysinit_sxlock global lock. */ static TAILQ_HEAD(vnet_sysinit_head, vnet_sysinit) vnet_constructors = TAILQ_HEAD_INITIALIZER(vnet_constructors); static TAILQ_HEAD(vnet_sysuninit_head, vnet_sysinit) vnet_destructors = TAILQ_HEAD_INITIALIZER(vnet_destructors); struct sx vnet_sysinit_sxlock; #define VNET_SYSINIT_WLOCK() sx_xlock(&vnet_sysinit_sxlock); #define VNET_SYSINIT_WUNLOCK() sx_xunlock(&vnet_sysinit_sxlock); #define VNET_SYSINIT_RLOCK() sx_slock(&vnet_sysinit_sxlock); #define VNET_SYSINIT_RUNLOCK() sx_sunlock(&vnet_sysinit_sxlock); struct vnet_data_free { uintptr_t vnd_start; int vnd_len; TAILQ_ENTRY(vnet_data_free) vnd_link; }; static MALLOC_DEFINE(M_VNET_DATA_FREE, "vnet_data_free", "VNET resource accounting"); static TAILQ_HEAD(, vnet_data_free) vnet_data_free_head = TAILQ_HEAD_INITIALIZER(vnet_data_free_head); static struct sx vnet_data_free_lock; SDT_PROVIDER_DEFINE(vnet); SDT_PROBE_DEFINE1(vnet, functions, vnet_alloc, entry, "int"); SDT_PROBE_DEFINE2(vnet, functions, vnet_alloc, alloc, "int", "struct vnet *"); SDT_PROBE_DEFINE2(vnet, functions, vnet_alloc, return, "int", "struct vnet *"); SDT_PROBE_DEFINE2(vnet, functions, vnet_destroy, entry, "int", "struct vnet *"); SDT_PROBE_DEFINE1(vnet, functions, vnet_destroy, return, "int"); #ifdef DDB static void db_show_vnet_print_vs(struct vnet_sysinit *, int); #endif /* * Allocate a virtual network stack. */ struct vnet * vnet_alloc(void) { struct vnet *vnet; SDT_PROBE1(vnet, functions, vnet_alloc, entry, __LINE__); vnet = malloc(sizeof(struct vnet), M_VNET, M_WAITOK | M_ZERO); vnet->vnet_magic_n = VNET_MAGIC_N; SDT_PROBE2(vnet, functions, vnet_alloc, alloc, __LINE__, vnet); /* * Allocate storage for virtualized global variables and copy in * initial values form our 'master' copy. */ vnet->vnet_data_mem = malloc(VNET_SIZE, M_VNET_DATA, M_WAITOK); memcpy(vnet->vnet_data_mem, (void *)VNET_START, VNET_BYTES); /* * All use of vnet-specific data will immediately subtract VNET_START * from the base memory pointer, so pre-calculate that now to avoid * it on each use. */ vnet->vnet_data_base = (uintptr_t)vnet->vnet_data_mem - VNET_START; /* Initialize / attach vnet module instances. */ CURVNET_SET_QUIET(vnet); vnet_sysinit(); CURVNET_RESTORE(); VNET_LIST_WLOCK(); LIST_INSERT_HEAD(&vnet_head, vnet, vnet_le); VNET_LIST_WUNLOCK(); SDT_PROBE2(vnet, functions, vnet_alloc, return, __LINE__, vnet); return (vnet); } /* * Destroy a virtual network stack. */ void vnet_destroy(struct vnet *vnet) { struct ifnet *ifp, *nifp; SDT_PROBE2(vnet, functions, vnet_destroy, entry, __LINE__, vnet); KASSERT(vnet->vnet_sockcnt == 0, ("%s: vnet still has sockets", __func__)); VNET_LIST_WLOCK(); LIST_REMOVE(vnet, vnet_le); VNET_LIST_WUNLOCK(); CURVNET_SET_QUIET(vnet); /* Return all inherited interfaces to their parent vnets. */ TAILQ_FOREACH_SAFE(ifp, &V_ifnet, if_link, nifp) { if (ifp->if_home_vnet != ifp->if_vnet) if_vmove(ifp, ifp->if_home_vnet); } vnet_sysuninit(); CURVNET_RESTORE(); /* * Release storage for the virtual network stack instance. */ free(vnet->vnet_data_mem, M_VNET_DATA); vnet->vnet_data_mem = NULL; vnet->vnet_data_base = 0; vnet->vnet_magic_n = 0xdeadbeef; free(vnet, M_VNET); SDT_PROBE1(vnet, functions, vnet_destroy, return, __LINE__); } /* * Boot time initialization and allocation of virtual network stacks. */ static void vnet_init_prelink(void *arg) { rw_init(&vnet_rwlock, "vnet_rwlock"); sx_init(&vnet_sxlock, "vnet_sxlock"); sx_init(&vnet_sysinit_sxlock, "vnet_sysinit_sxlock"); LIST_INIT(&vnet_head); } SYSINIT(vnet_init_prelink, SI_SUB_VNET_PRELINK, SI_ORDER_FIRST, vnet_init_prelink, NULL); static void vnet0_init(void *arg) { /* Warn people before take off - in case we crash early. */ printf("WARNING: VIMAGE (virtualized network stack) is a highly " "experimental feature.\n"); /* * We MUST clear curvnet in vi_init_done() before going SMP, * otherwise CURVNET_SET() macros would scream about unnecessary * curvnet recursions. */ curvnet = prison0.pr_vnet = vnet0 = vnet_alloc(); } SYSINIT(vnet0_init, SI_SUB_VNET, SI_ORDER_FIRST, vnet0_init, NULL); static void vnet_init_done(void *unused) { curvnet = NULL; } SYSINIT(vnet_init_done, SI_SUB_VNET_DONE, SI_ORDER_FIRST, vnet_init_done, NULL); /* * Once on boot, initialize the modspace freelist to entirely cover modspace. */ static void vnet_data_startup(void *dummy __unused) { struct vnet_data_free *df; df = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO); df->vnd_start = (uintptr_t)&VNET_NAME(modspace); df->vnd_len = VNET_MODMIN; TAILQ_INSERT_HEAD(&vnet_data_free_head, df, vnd_link); sx_init(&vnet_data_free_lock, "vnet_data alloc lock"); } SYSINIT(vnet_data, SI_SUB_KLD, SI_ORDER_FIRST, vnet_data_startup, 0); /* * When a module is loaded and requires storage for a virtualized global * variable, allocate space from the modspace free list. This interface * should be used only by the kernel linker. */ void * vnet_data_alloc(int size) { struct vnet_data_free *df; void *s; s = NULL; size = roundup2(size, sizeof(void *)); sx_xlock(&vnet_data_free_lock); TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) { if (df->vnd_len < size) continue; if (df->vnd_len == size) { s = (void *)df->vnd_start; TAILQ_REMOVE(&vnet_data_free_head, df, vnd_link); free(df, M_VNET_DATA_FREE); break; } s = (void *)df->vnd_start; df->vnd_len -= size; df->vnd_start = df->vnd_start + size; break; } sx_xunlock(&vnet_data_free_lock); return (s); } /* * Free space for a virtualized global variable on module unload. */ void vnet_data_free(void *start_arg, int size) { struct vnet_data_free *df; struct vnet_data_free *dn; uintptr_t start; uintptr_t end; size = roundup2(size, sizeof(void *)); start = (uintptr_t)start_arg; end = start + size; /* * Free a region of space and merge it with as many neighbors as * possible. Keeping the list sorted simplifies this operation. */ sx_xlock(&vnet_data_free_lock); TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) { if (df->vnd_start > end) break; /* * If we expand at the end of an entry we may have to merge * it with the one following it as well. */ if (df->vnd_start + df->vnd_len == start) { df->vnd_len += size; dn = TAILQ_NEXT(df, vnd_link); if (df->vnd_start + df->vnd_len == dn->vnd_start) { df->vnd_len += dn->vnd_len; TAILQ_REMOVE(&vnet_data_free_head, dn, vnd_link); free(dn, M_VNET_DATA_FREE); } sx_xunlock(&vnet_data_free_lock); return; } if (df->vnd_start == end) { df->vnd_start = start; df->vnd_len += size; sx_xunlock(&vnet_data_free_lock); return; } } dn = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO); dn->vnd_start = start; dn->vnd_len = size; if (df) TAILQ_INSERT_BEFORE(df, dn, vnd_link); else TAILQ_INSERT_TAIL(&vnet_data_free_head, dn, vnd_link); sx_xunlock(&vnet_data_free_lock); } /* * When a new virtualized global variable has been allocated, propagate its * initial value to each already-allocated virtual network stack instance. */ void vnet_data_copy(void *start, int size) { struct vnet *vnet; VNET_LIST_RLOCK(); LIST_FOREACH(vnet, &vnet_head, vnet_le) memcpy((void *)((uintptr_t)vnet->vnet_data_base + (uintptr_t)start), start, size); VNET_LIST_RUNLOCK(); } /* * Support for special SYSINIT handlers registered via VNET_SYSINIT() * and VNET_SYSUNINIT(). */ void vnet_register_sysinit(void *arg) { struct vnet_sysinit *vs, *vs2; struct vnet *vnet; vs = arg; KASSERT(vs->subsystem > SI_SUB_VNET, ("vnet sysinit too early")); /* Add the constructor to the global list of vnet constructors. */ VNET_SYSINIT_WLOCK(); TAILQ_FOREACH(vs2, &vnet_constructors, link) { if (vs2->subsystem > vs->subsystem) break; if (vs2->subsystem == vs->subsystem && vs2->order > vs->order) break; } if (vs2 != NULL) TAILQ_INSERT_BEFORE(vs2, vs, link); else TAILQ_INSERT_TAIL(&vnet_constructors, vs, link); /* * Invoke the constructor on all the existing vnets when it is * registered. */ VNET_FOREACH(vnet) { CURVNET_SET_QUIET(vnet); vs->func(vs->arg); CURVNET_RESTORE(); } VNET_SYSINIT_WUNLOCK(); } void vnet_deregister_sysinit(void *arg) { struct vnet_sysinit *vs; vs = arg; /* Remove the constructor from the global list of vnet constructors. */ VNET_SYSINIT_WLOCK(); TAILQ_REMOVE(&vnet_constructors, vs, link); VNET_SYSINIT_WUNLOCK(); } void vnet_register_sysuninit(void *arg) { struct vnet_sysinit *vs, *vs2; vs = arg; /* Add the destructor to the global list of vnet destructors. */ VNET_SYSINIT_WLOCK(); TAILQ_FOREACH(vs2, &vnet_destructors, link) { if (vs2->subsystem > vs->subsystem) break; if (vs2->subsystem == vs->subsystem && vs2->order > vs->order) break; } if (vs2 != NULL) TAILQ_INSERT_BEFORE(vs2, vs, link); else TAILQ_INSERT_TAIL(&vnet_destructors, vs, link); VNET_SYSINIT_WUNLOCK(); } void vnet_deregister_sysuninit(void *arg) { struct vnet_sysinit *vs; struct vnet *vnet; vs = arg; /* * Invoke the destructor on all the existing vnets when it is * deregistered. */ VNET_SYSINIT_WLOCK(); VNET_FOREACH(vnet) { CURVNET_SET_QUIET(vnet); vs->func(vs->arg); CURVNET_RESTORE(); } /* Remove the destructor from the global list of vnet destructors. */ TAILQ_REMOVE(&vnet_destructors, vs, link); VNET_SYSINIT_WUNLOCK(); } /* * Invoke all registered vnet constructors on the current vnet. Used during * vnet construction. The caller is responsible for ensuring the new vnet is * the current vnet and that the vnet_sysinit_sxlock lock is locked. */ void vnet_sysinit(void) { struct vnet_sysinit *vs; VNET_SYSINIT_RLOCK(); TAILQ_FOREACH(vs, &vnet_constructors, link) { vs->func(vs->arg); } VNET_SYSINIT_RUNLOCK(); } /* * Invoke all registered vnet destructors on the current vnet. Used during * vnet destruction. The caller is responsible for ensuring the dying vnet * the current vnet and that the vnet_sysinit_sxlock lock is locked. */ void vnet_sysuninit(void) { struct vnet_sysinit *vs; VNET_SYSINIT_RLOCK(); TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head, link) { vs->func(vs->arg); } VNET_SYSINIT_RUNLOCK(); } /* * EVENTHANDLER(9) extensions. */ /* * Invoke the eventhandler function originally registered with the possibly * registered argument for all virtual network stack instances. * * This iterator can only be used for eventhandlers that do not take any * additional arguments, as we do ignore the variadic arguments from the * EVENTHANDLER_INVOKE() call. */ void vnet_global_eventhandler_iterator_func(void *arg, ...) { VNET_ITERATOR_DECL(vnet_iter); struct eventhandler_entry_vimage *v_ee; /* * There is a bug here in that we should actually cast things to * (struct eventhandler_entry_ ## name *) but that's not easily * possible in here so just re-using the variadic version we * defined for the generic vimage case. */ v_ee = arg; VNET_LIST_RLOCK(); VNET_FOREACH(vnet_iter) { CURVNET_SET(vnet_iter); ((vimage_iterator_func_t)v_ee->func)(v_ee->ee_arg); CURVNET_RESTORE(); } VNET_LIST_RUNLOCK(); } #ifdef VNET_DEBUG struct vnet_recursion { SLIST_ENTRY(vnet_recursion) vnr_le; const char *prev_fn; const char *where_fn; int where_line; struct vnet *old_vnet; struct vnet *new_vnet; }; static SLIST_HEAD(, vnet_recursion) vnet_recursions = SLIST_HEAD_INITIALIZER(vnet_recursions); static void vnet_print_recursion(struct vnet_recursion *vnr, int brief) { if (!brief) printf("CURVNET_SET() recursion in "); printf("%s() line %d, prev in %s()", vnr->where_fn, vnr->where_line, vnr->prev_fn); if (brief) printf(", "); else printf("\n "); printf("%p -> %p\n", vnr->old_vnet, vnr->new_vnet); } void vnet_log_recursion(struct vnet *old_vnet, const char *old_fn, int line) { struct vnet_recursion *vnr; /* Skip already logged recursion events. */ SLIST_FOREACH(vnr, &vnet_recursions, vnr_le) if (vnr->prev_fn == old_fn && vnr->where_fn == curthread->td_vnet_lpush && vnr->where_line == line && (vnr->old_vnet == vnr->new_vnet) == (curvnet == old_vnet)) return; vnr = malloc(sizeof(*vnr), M_VNET, M_NOWAIT | M_ZERO); if (vnr == NULL) panic("%s: malloc failed", __func__); vnr->prev_fn = old_fn; vnr->where_fn = curthread->td_vnet_lpush; vnr->where_line = line; vnr->old_vnet = old_vnet; vnr->new_vnet = curvnet; SLIST_INSERT_HEAD(&vnet_recursions, vnr, vnr_le); vnet_print_recursion(vnr, 0); #ifdef KDB kdb_backtrace(); #endif } #endif /* VNET_DEBUG */ /* * DDB(4). */ #ifdef DDB DB_SHOW_COMMAND(vnets, db_show_vnets) { VNET_ITERATOR_DECL(vnet_iter); VNET_FOREACH(vnet_iter) { db_printf("vnet = %p\n", vnet_iter); db_printf(" vnet_magic_n = 0x%x (%s, orig 0x%x)\n", vnet_iter->vnet_magic_n, (vnet_iter->vnet_magic_n == VNET_MAGIC_N) ? "ok" : "mismatch", VNET_MAGIC_N); db_printf(" vnet_ifcnt = %u\n", vnet_iter->vnet_ifcnt); db_printf(" vnet_sockcnt = %u\n", vnet_iter->vnet_sockcnt); db_printf(" vnet_data_mem = %p\n", vnet_iter->vnet_data_mem); db_printf(" vnet_data_base = 0x%jx\n", (uintmax_t)vnet_iter->vnet_data_base); db_printf("\n"); if (db_pager_quit) break; } } static void db_show_vnet_print_vs(struct vnet_sysinit *vs, int ddb) { const char *vsname, *funcname; c_db_sym_t sym; db_expr_t offset; #define xprint(...) \ if (ddb) \ db_printf(__VA_ARGS__); \ else \ printf(__VA_ARGS__) if (vs == NULL) { xprint("%s: no vnet_sysinit * given\n", __func__); return; } sym = db_search_symbol((vm_offset_t)vs, DB_STGY_ANY, &offset); db_symbol_values(sym, &vsname, NULL); sym = db_search_symbol((vm_offset_t)vs->func, DB_STGY_PROC, &offset); db_symbol_values(sym, &funcname, NULL); xprint("%s(%p)\n", (vsname != NULL) ? vsname : "", vs); xprint(" 0x%08x 0x%08x\n", vs->subsystem, vs->order); xprint(" %p(%s)(%p)\n", vs->func, (funcname != NULL) ? funcname : "", vs->arg); #undef xprint } DB_SHOW_COMMAND(vnet_sysinit, db_show_vnet_sysinit) { struct vnet_sysinit *vs; db_printf("VNET_SYSINIT vs Name(Ptr)\n"); db_printf(" Subsystem Order\n"); db_printf(" Function(Name)(Arg)\n"); TAILQ_FOREACH(vs, &vnet_constructors, link) { db_show_vnet_print_vs(vs, 1); if (db_pager_quit) break; } } DB_SHOW_COMMAND(vnet_sysuninit, db_show_vnet_sysuninit) { struct vnet_sysinit *vs; db_printf("VNET_SYSUNINIT vs Name(Ptr)\n"); db_printf(" Subsystem Order\n"); db_printf(" Function(Name)(Arg)\n"); TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head, link) { db_show_vnet_print_vs(vs, 1); if (db_pager_quit) break; } } #ifdef VNET_DEBUG DB_SHOW_COMMAND(vnetrcrs, db_show_vnetrcrs) { struct vnet_recursion *vnr; SLIST_FOREACH(vnr, &vnet_recursions, vnr_le) vnet_print_recursion(vnr, 1); } #endif #endif /* DDB */