/*-
* 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 <sys/param.h>
#include <sys/kernel.h>
#include <sys/jail.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/linker_set.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>
#ifdef DDB
#include <ddb/ddb.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.
*/
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.
*/
/*
* Location of the kernel's 'set_vnet' linker set.
*/
extern uintptr_t *__start_set_vnet;
extern uintptr_t *__stop_set_vnet;
#define VNET_START (uintptr_t)&__start_set_vnet
#define VNET_STOP (uintptr_t)&__stop_set_vnet
/*
* 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)
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;
};
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;
/*
* Allocate a virtual network stack.
*/
struct vnet *
vnet_alloc(void)
{
struct vnet *vnet;
vnet = malloc(sizeof(struct vnet), M_VNET, M_WAITOK | M_ZERO);
vnet->vnet_magic_n = VNET_MAGIC_N;
/*
* 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();
return (vnet);
}
/*
* Destroy a virtual network stack.
*/
void
vnet_destroy(struct vnet *vnet)
{
struct ifnet *ifp, *nifp;
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);
}
/*
* 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_MODSIZE;
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();
}
/*
* Variants on sysctl_handle_foo that know how to handle virtualized global
* variables: if 'arg1' is a pointer, then we transform it to the local vnet
* offset.
*/
int
vnet_sysctl_handle_int(SYSCTL_HANDLER_ARGS)
{
if (arg1 != NULL)
arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
return (sysctl_handle_int(oidp, arg1, arg2, req));
}
int
vnet_sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
{
if (arg1 != NULL)
arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
return (sysctl_handle_opaque(oidp, arg1, arg2, req));
}
int
vnet_sysctl_handle_string(SYSCTL_HANDLER_ARGS)
{
if (arg1 != NULL)
arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
return (sysctl_handle_string(oidp, arg1, arg2, req));
}
int
vnet_sysctl_handle_uint(SYSCTL_HANDLER_ARGS)
{
if (arg1 != NULL)
arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
return (sysctl_handle_int(oidp, arg1, arg2, req));
}
/*
* 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();
}
#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;
}
}
#endif
