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linux-hardened/net/xfrm/xfrm_policy.c
Herbert Xu 4666faab09 [IPSEC] Kill spurious hard expire messages 
This patch ensures that the hard state/policy expire notifications are
only sent when the state/policy is successfully removed from their
respective tables.

As it is, it's possible for a state/policy to both expire through
reaching a hard limit, as well as being deleted by the user.

Note that this behaviour isn't actually forbidden by RFC 2367.
However, it is a quality of implementation issue.

As an added bonus, the restructuring in this patch will help
eventually in moving the expire notifications from softirq
context into process context, thus improving their reliability.

One important side-effect from this change is that SAs reaching
their hard byte/packet limits are now deleted immediately, just
like SAs that have reached their hard time limits.

Previously they were announced immediately but only deleted after
30 seconds.

This is bad because it prevents the system from issuing an ACQUIRE
command until the existing state was deleted by the user or expires
after the time is up.

In the scenario where the expire notification was lost this introduces
a 30 second delay into the system for no good reason.
 
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2005-06-18 22:43:22 -07:00

1348 lines
30 KiB
C
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/*
* xfrm_policy.c
*
* Changes:
* Mitsuru KANDA @USAGI
* Kazunori MIYAZAWA @USAGI
* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
* IPv6 support
* Kazunori MIYAZAWA @USAGI
* YOSHIFUJI Hideaki
* Split up af-specific portion
* Derek Atkins <derek@ihtfp.com> Add the post_input processor
*
*/
#include <asm/bug.h>
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <net/xfrm.h>
#include <net/ip.h>
DECLARE_MUTEX(xfrm_cfg_sem);
EXPORT_SYMBOL(xfrm_cfg_sem);
static DEFINE_RWLOCK(xfrm_policy_lock);
struct xfrm_policy *xfrm_policy_list[XFRM_POLICY_MAX*2];
EXPORT_SYMBOL(xfrm_policy_list);
static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
static kmem_cache_t *xfrm_dst_cache;
static struct work_struct xfrm_policy_gc_work;
static struct list_head xfrm_policy_gc_list =
LIST_HEAD_INIT(xfrm_policy_gc_list);
static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
int xfrm_register_type(struct xfrm_type *type, unsigned short family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
struct xfrm_type_map *typemap;
int err = 0;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
typemap = afinfo->type_map;
write_lock(&typemap->lock);
if (likely(typemap->map[type->proto] == NULL))
typemap->map[type->proto] = type;
else
err = -EEXIST;
write_unlock(&typemap->lock);
xfrm_policy_put_afinfo(afinfo);
return err;
}
EXPORT_SYMBOL(xfrm_register_type);
int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
struct xfrm_type_map *typemap;
int err = 0;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
typemap = afinfo->type_map;
write_lock(&typemap->lock);
if (unlikely(typemap->map[type->proto] != type))
err = -ENOENT;
else
typemap->map[type->proto] = NULL;
write_unlock(&typemap->lock);
xfrm_policy_put_afinfo(afinfo);
return err;
}
EXPORT_SYMBOL(xfrm_unregister_type);
struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
{
struct xfrm_policy_afinfo *afinfo;
struct xfrm_type_map *typemap;
struct xfrm_type *type;
int modload_attempted = 0;
retry:
afinfo = xfrm_policy_get_afinfo(family);
if (unlikely(afinfo == NULL))
return NULL;
typemap = afinfo->type_map;
read_lock(&typemap->lock);
type = typemap->map[proto];
if (unlikely(type && !try_module_get(type->owner)))
type = NULL;
read_unlock(&typemap->lock);
if (!type && !modload_attempted) {
xfrm_policy_put_afinfo(afinfo);
request_module("xfrm-type-%d-%d",
(int) family, (int) proto);
modload_attempted = 1;
goto retry;
}
xfrm_policy_put_afinfo(afinfo);
return type;
}
EXPORT_SYMBOL(xfrm_get_type);
int xfrm_dst_lookup(struct xfrm_dst **dst, struct flowi *fl,
unsigned short family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
int err = 0;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
if (likely(afinfo->dst_lookup != NULL))
err = afinfo->dst_lookup(dst, fl);
else
err = -EINVAL;
xfrm_policy_put_afinfo(afinfo);
return err;
}
EXPORT_SYMBOL(xfrm_dst_lookup);
void xfrm_put_type(struct xfrm_type *type)
{
module_put(type->owner);
}
static inline unsigned long make_jiffies(long secs)
{
if (secs >= (MAX_SCHEDULE_TIMEOUT-1)/HZ)
return MAX_SCHEDULE_TIMEOUT-1;
else
return secs*HZ;
}
static void xfrm_policy_timer(unsigned long data)
{
struct xfrm_policy *xp = (struct xfrm_policy*)data;
unsigned long now = (unsigned long)xtime.tv_sec;
long next = LONG_MAX;
int warn = 0;
int dir;
read_lock(&xp->lock);
if (xp->dead)
goto out;
dir = xp->index & 7;
if (xp->lft.hard_add_expires_seconds) {
long tmo = xp->lft.hard_add_expires_seconds +
xp->curlft.add_time - now;
if (tmo <= 0)
goto expired;
if (tmo < next)
next = tmo;
}
if (xp->lft.hard_use_expires_seconds) {
long tmo = xp->lft.hard_use_expires_seconds +
(xp->curlft.use_time ? : xp->curlft.add_time) - now;
if (tmo <= 0)
goto expired;
if (tmo < next)
next = tmo;
}
if (xp->lft.soft_add_expires_seconds) {
long tmo = xp->lft.soft_add_expires_seconds +
xp->curlft.add_time - now;
if (tmo <= 0) {
warn = 1;
tmo = XFRM_KM_TIMEOUT;
}
if (tmo < next)
next = tmo;
}
if (xp->lft.soft_use_expires_seconds) {
long tmo = xp->lft.soft_use_expires_seconds +
(xp->curlft.use_time ? : xp->curlft.add_time) - now;
if (tmo <= 0) {
warn = 1;
tmo = XFRM_KM_TIMEOUT;
}
if (tmo < next)
next = tmo;
}
if (warn)
km_policy_expired(xp, dir, 0);
if (next != LONG_MAX &&
!mod_timer(&xp->timer, jiffies + make_jiffies(next)))
xfrm_pol_hold(xp);
out:
read_unlock(&xp->lock);
xfrm_pol_put(xp);
return;
expired:
read_unlock(&xp->lock);
if (!xfrm_policy_delete(xp, dir))
km_policy_expired(xp, dir, 1);
xfrm_pol_put(xp);
}
/* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
* SPD calls.
*/
struct xfrm_policy *xfrm_policy_alloc(int gfp)
{
struct xfrm_policy *policy;
policy = kmalloc(sizeof(struct xfrm_policy), gfp);
if (policy) {
memset(policy, 0, sizeof(struct xfrm_policy));
atomic_set(&policy->refcnt, 1);
rwlock_init(&policy->lock);
init_timer(&policy->timer);
policy->timer.data = (unsigned long)policy;
policy->timer.function = xfrm_policy_timer;
}
return policy;
}
EXPORT_SYMBOL(xfrm_policy_alloc);
/* Destroy xfrm_policy: descendant resources must be released to this moment. */
void __xfrm_policy_destroy(struct xfrm_policy *policy)
{
if (!policy->dead)
BUG();
if (policy->bundles)
BUG();
if (del_timer(&policy->timer))
BUG();
kfree(policy);
}
EXPORT_SYMBOL(__xfrm_policy_destroy);
static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
{
struct dst_entry *dst;
while ((dst = policy->bundles) != NULL) {
policy->bundles = dst->next;
dst_free(dst);
}
if (del_timer(&policy->timer))
atomic_dec(&policy->refcnt);
if (atomic_read(&policy->refcnt) > 1)
flow_cache_flush();
xfrm_pol_put(policy);
}
static void xfrm_policy_gc_task(void *data)
{
struct xfrm_policy *policy;
struct list_head *entry, *tmp;
struct list_head gc_list = LIST_HEAD_INIT(gc_list);
spin_lock_bh(&xfrm_policy_gc_lock);
list_splice_init(&xfrm_policy_gc_list, &gc_list);
spin_unlock_bh(&xfrm_policy_gc_lock);
list_for_each_safe(entry, tmp, &gc_list) {
policy = list_entry(entry, struct xfrm_policy, list);
xfrm_policy_gc_kill(policy);
}
}
/* Rule must be locked. Release descentant resources, announce
* entry dead. The rule must be unlinked from lists to the moment.
*/
static void xfrm_policy_kill(struct xfrm_policy *policy)
{
int dead;
write_lock_bh(&policy->lock);
dead = policy->dead;
policy->dead = 1;
write_unlock_bh(&policy->lock);
if (unlikely(dead)) {
WARN_ON(1);
return;
}
spin_lock(&xfrm_policy_gc_lock);
list_add(&policy->list, &xfrm_policy_gc_list);
spin_unlock(&xfrm_policy_gc_lock);
schedule_work(&xfrm_policy_gc_work);
}
/* Generate new index... KAME seems to generate them ordered by cost
* of an absolute inpredictability of ordering of rules. This will not pass. */
static u32 xfrm_gen_index(int dir)
{
u32 idx;
struct xfrm_policy *p;
static u32 idx_generator;
for (;;) {
idx = (idx_generator | dir);
idx_generator += 8;
if (idx == 0)
idx = 8;
for (p = xfrm_policy_list[dir]; p; p = p->next) {
if (p->index == idx)
break;
}
if (!p)
return idx;
}
}
int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
{
struct xfrm_policy *pol, **p;
struct xfrm_policy *delpol = NULL;
struct xfrm_policy **newpos = NULL;
write_lock_bh(&xfrm_policy_lock);
for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL;) {
if (!delpol && memcmp(&policy->selector, &pol->selector, sizeof(pol->selector)) == 0) {
if (excl) {
write_unlock_bh(&xfrm_policy_lock);
return -EEXIST;
}
*p = pol->next;
delpol = pol;
if (policy->priority > pol->priority)
continue;
} else if (policy->priority >= pol->priority) {
p = &pol->next;
continue;
}
if (!newpos)
newpos = p;
if (delpol)
break;
p = &pol->next;
}
if (newpos)
p = newpos;
xfrm_pol_hold(policy);
policy->next = *p;
*p = policy;
atomic_inc(&flow_cache_genid);
policy->index = delpol ? delpol->index : xfrm_gen_index(dir);
policy->curlft.add_time = (unsigned long)xtime.tv_sec;
policy->curlft.use_time = 0;
if (!mod_timer(&policy->timer, jiffies + HZ))
xfrm_pol_hold(policy);
write_unlock_bh(&xfrm_policy_lock);
if (delpol) {
xfrm_policy_kill(delpol);
}
return 0;
}
EXPORT_SYMBOL(xfrm_policy_insert);
struct xfrm_policy *xfrm_policy_bysel(int dir, struct xfrm_selector *sel,
int delete)
{
struct xfrm_policy *pol, **p;
write_lock_bh(&xfrm_policy_lock);
for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
if (memcmp(sel, &pol->selector, sizeof(*sel)) == 0) {
xfrm_pol_hold(pol);
if (delete)
*p = pol->next;
break;
}
}
write_unlock_bh(&xfrm_policy_lock);
if (pol && delete) {
atomic_inc(&flow_cache_genid);
xfrm_policy_kill(pol);
}
return pol;
}
EXPORT_SYMBOL(xfrm_policy_bysel);
struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete)
{
struct xfrm_policy *pol, **p;
write_lock_bh(&xfrm_policy_lock);
for (p = &xfrm_policy_list[id & 7]; (pol=*p)!=NULL; p = &pol->next) {
if (pol->index == id) {
xfrm_pol_hold(pol);
if (delete)
*p = pol->next;
break;
}
}
write_unlock_bh(&xfrm_policy_lock);
if (pol && delete) {
atomic_inc(&flow_cache_genid);
xfrm_policy_kill(pol);
}
return pol;
}
EXPORT_SYMBOL(xfrm_policy_byid);
void xfrm_policy_flush(void)
{
struct xfrm_policy *xp;
int dir;
write_lock_bh(&xfrm_policy_lock);
for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
while ((xp = xfrm_policy_list[dir]) != NULL) {
xfrm_policy_list[dir] = xp->next;
write_unlock_bh(&xfrm_policy_lock);
xfrm_policy_kill(xp);
write_lock_bh(&xfrm_policy_lock);
}
}
atomic_inc(&flow_cache_genid);
write_unlock_bh(&xfrm_policy_lock);
}
EXPORT_SYMBOL(xfrm_policy_flush);
int xfrm_policy_walk(int (*func)(struct xfrm_policy *, int, int, void*),
void *data)
{
struct xfrm_policy *xp;
int dir;
int count = 0;
int error = 0;
read_lock_bh(&xfrm_policy_lock);
for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
for (xp = xfrm_policy_list[dir]; xp; xp = xp->next)
count++;
}
if (count == 0) {
error = -ENOENT;
goto out;
}
for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
for (xp = xfrm_policy_list[dir]; xp; xp = xp->next) {
error = func(xp, dir%XFRM_POLICY_MAX, --count, data);
if (error)
goto out;
}
}
out:
read_unlock_bh(&xfrm_policy_lock);
return error;
}
EXPORT_SYMBOL(xfrm_policy_walk);
/* Find policy to apply to this flow. */
static void xfrm_policy_lookup(struct flowi *fl, u16 family, u8 dir,
void **objp, atomic_t **obj_refp)
{
struct xfrm_policy *pol;
read_lock_bh(&xfrm_policy_lock);
for (pol = xfrm_policy_list[dir]; pol; pol = pol->next) {
struct xfrm_selector *sel = &pol->selector;
int match;
if (pol->family != family)
continue;
match = xfrm_selector_match(sel, fl, family);
if (match) {
xfrm_pol_hold(pol);
break;
}
}
read_unlock_bh(&xfrm_policy_lock);
if ((*objp = (void *) pol) != NULL)
*obj_refp = &pol->refcnt;
}
static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struct flowi *fl)
{
struct xfrm_policy *pol;
read_lock_bh(&xfrm_policy_lock);
if ((pol = sk->sk_policy[dir]) != NULL) {
int match = xfrm_selector_match(&pol->selector, fl,
sk->sk_family);
if (match)
xfrm_pol_hold(pol);
else
pol = NULL;
}
read_unlock_bh(&xfrm_policy_lock);
return pol;
}
static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
{
pol->next = xfrm_policy_list[dir];
xfrm_policy_list[dir] = pol;
xfrm_pol_hold(pol);
}
static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
int dir)
{
struct xfrm_policy **polp;
for (polp = &xfrm_policy_list[dir];
*polp != NULL; polp = &(*polp)->next) {
if (*polp == pol) {
*polp = pol->next;
return pol;
}
}
return NULL;
}
int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
{
write_lock_bh(&xfrm_policy_lock);
pol = __xfrm_policy_unlink(pol, dir);
write_unlock_bh(&xfrm_policy_lock);
if (pol) {
if (dir < XFRM_POLICY_MAX)
atomic_inc(&flow_cache_genid);
xfrm_policy_kill(pol);
return 0;
}
return -ENOENT;
}
int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
{
struct xfrm_policy *old_pol;
write_lock_bh(&xfrm_policy_lock);
old_pol = sk->sk_policy[dir];
sk->sk_policy[dir] = pol;
if (pol) {
pol->curlft.add_time = (unsigned long)xtime.tv_sec;
pol->index = xfrm_gen_index(XFRM_POLICY_MAX+dir);
__xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
}
if (old_pol)
__xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
write_unlock_bh(&xfrm_policy_lock);
if (old_pol) {
xfrm_policy_kill(old_pol);
}
return 0;
}
static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
{
struct xfrm_policy *newp = xfrm_policy_alloc(GFP_ATOMIC);
if (newp) {
newp->selector = old->selector;
newp->lft = old->lft;
newp->curlft = old->curlft;
newp->action = old->action;
newp->flags = old->flags;
newp->xfrm_nr = old->xfrm_nr;
newp->index = old->index;
memcpy(newp->xfrm_vec, old->xfrm_vec,
newp->xfrm_nr*sizeof(struct xfrm_tmpl));
write_lock_bh(&xfrm_policy_lock);
__xfrm_policy_link(newp, XFRM_POLICY_MAX+dir);
write_unlock_bh(&xfrm_policy_lock);
xfrm_pol_put(newp);
}
return newp;
}
int __xfrm_sk_clone_policy(struct sock *sk)
{
struct xfrm_policy *p0 = sk->sk_policy[0],
*p1 = sk->sk_policy[1];
sk->sk_policy[0] = sk->sk_policy[1] = NULL;
if (p0 && (sk->sk_policy[0] = clone_policy(p0, 0)) == NULL)
return -ENOMEM;
if (p1 && (sk->sk_policy[1] = clone_policy(p1, 1)) == NULL)
return -ENOMEM;
return 0;
}
/* Resolve list of templates for the flow, given policy. */
static int
xfrm_tmpl_resolve(struct xfrm_policy *policy, struct flowi *fl,
struct xfrm_state **xfrm,
unsigned short family)
{
int nx;
int i, error;
xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
for (nx=0, i = 0; i < policy->xfrm_nr; i++) {
struct xfrm_state *x;
xfrm_address_t *remote = daddr;
xfrm_address_t *local = saddr;
struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
if (tmpl->mode) {
remote = &tmpl->id.daddr;
local = &tmpl->saddr;
}
x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
if (x && x->km.state == XFRM_STATE_VALID) {
xfrm[nx++] = x;
daddr = remote;
saddr = local;
continue;
}
if (x) {
error = (x->km.state == XFRM_STATE_ERROR ?
-EINVAL : -EAGAIN);
xfrm_state_put(x);
}
if (!tmpl->optional)
goto fail;
}
return nx;
fail:
for (nx--; nx>=0; nx--)
xfrm_state_put(xfrm[nx]);
return error;
}
/* Check that the bundle accepts the flow and its components are
* still valid.
*/
static struct dst_entry *
xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short family)
{
struct dst_entry *x;
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
if (unlikely(afinfo == NULL))
return ERR_PTR(-EINVAL);
x = afinfo->find_bundle(fl, policy);
xfrm_policy_put_afinfo(afinfo);
return x;
}
/* Allocate chain of dst_entry's, attach known xfrm's, calculate
* all the metrics... Shortly, bundle a bundle.
*/
static int
xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
struct flowi *fl, struct dst_entry **dst_p,
unsigned short family)
{
int err;
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
if (unlikely(afinfo == NULL))
return -EINVAL;
err = afinfo->bundle_create(policy, xfrm, nx, fl, dst_p);
xfrm_policy_put_afinfo(afinfo);
return err;
}
static inline int policy_to_flow_dir(int dir)
{
if (XFRM_POLICY_IN == FLOW_DIR_IN &&
XFRM_POLICY_OUT == FLOW_DIR_OUT &&
XFRM_POLICY_FWD == FLOW_DIR_FWD)
return dir;
switch (dir) {
default:
case XFRM_POLICY_IN:
return FLOW_DIR_IN;
case XFRM_POLICY_OUT:
return FLOW_DIR_OUT;
case XFRM_POLICY_FWD:
return FLOW_DIR_FWD;
};
}
static int stale_bundle(struct dst_entry *dst);
/* Main function: finds/creates a bundle for given flow.
*
* At the moment we eat a raw IP route. Mostly to speed up lookups
* on interfaces with disabled IPsec.
*/
int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
struct sock *sk, int flags)
{
struct xfrm_policy *policy;
struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
struct dst_entry *dst, *dst_orig = *dst_p;
int nx = 0;
int err;
u32 genid;
u16 family = dst_orig->ops->family;
restart:
genid = atomic_read(&flow_cache_genid);
policy = NULL;
if (sk && sk->sk_policy[1])
policy = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
if (!policy) {
/* To accelerate a bit... */
if ((dst_orig->flags & DST_NOXFRM) || !xfrm_policy_list[XFRM_POLICY_OUT])
return 0;
policy = flow_cache_lookup(fl, family,
policy_to_flow_dir(XFRM_POLICY_OUT),
xfrm_policy_lookup);
}
if (!policy)
return 0;
policy->curlft.use_time = (unsigned long)xtime.tv_sec;
switch (policy->action) {
case XFRM_POLICY_BLOCK:
/* Prohibit the flow */
xfrm_pol_put(policy);
return -EPERM;
case XFRM_POLICY_ALLOW:
if (policy->xfrm_nr == 0) {
/* Flow passes not transformed. */
xfrm_pol_put(policy);
return 0;
}
/* Try to find matching bundle.
*
* LATER: help from flow cache. It is optional, this
* is required only for output policy.
*/
dst = xfrm_find_bundle(fl, policy, family);
if (IS_ERR(dst)) {
xfrm_pol_put(policy);
return PTR_ERR(dst);
}
if (dst)
break;
nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
if (unlikely(nx<0)) {
err = nx;
if (err == -EAGAIN && flags) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(&km_waitq, &wait);
set_current_state(TASK_INTERRUPTIBLE);
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&km_waitq, &wait);
nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
if (nx == -EAGAIN && signal_pending(current)) {
err = -ERESTART;
goto error;
}
if (nx == -EAGAIN ||
genid != atomic_read(&flow_cache_genid)) {
xfrm_pol_put(policy);
goto restart;
}
err = nx;
}
if (err < 0)
goto error;
}
if (nx == 0) {
/* Flow passes not transformed. */
xfrm_pol_put(policy);
return 0;
}
dst = dst_orig;
err = xfrm_bundle_create(policy, xfrm, nx, fl, &dst, family);
if (unlikely(err)) {
int i;
for (i=0; i<nx; i++)
xfrm_state_put(xfrm[i]);
goto error;
}
write_lock_bh(&policy->lock);
if (unlikely(policy->dead || stale_bundle(dst))) {
/* Wow! While we worked on resolving, this
* policy has gone. Retry. It is not paranoia,
* we just cannot enlist new bundle to dead object.
* We can't enlist stable bundles either.
*/
write_unlock_bh(&policy->lock);
xfrm_pol_put(policy);
if (dst)
dst_free(dst);
goto restart;
}
dst->next = policy->bundles;
policy->bundles = dst;
dst_hold(dst);
write_unlock_bh(&policy->lock);
}
*dst_p = dst;
dst_release(dst_orig);
xfrm_pol_put(policy);
return 0;
error:
dst_release(dst_orig);
xfrm_pol_put(policy);
*dst_p = NULL;
return err;
}
EXPORT_SYMBOL(xfrm_lookup);
/* When skb is transformed back to its "native" form, we have to
* check policy restrictions. At the moment we make this in maximally
* stupid way. Shame on me. :-) Of course, connected sockets must
* have policy cached at them.
*/
static inline int
xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x,
unsigned short family)
{
if (xfrm_state_kern(x))
return tmpl->optional && !xfrm_state_addr_cmp(tmpl, x, family);
return x->id.proto == tmpl->id.proto &&
(x->id.spi == tmpl->id.spi || !tmpl->id.spi) &&
(x->props.reqid == tmpl->reqid || !tmpl->reqid) &&
x->props.mode == tmpl->mode &&
(tmpl->aalgos & (1<<x->props.aalgo)) &&
!(x->props.mode && xfrm_state_addr_cmp(tmpl, x, family));
}
static inline int
xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
unsigned short family)
{
int idx = start;
if (tmpl->optional) {
if (!tmpl->mode)
return start;
} else
start = -1;
for (; idx < sp->len; idx++) {
if (xfrm_state_ok(tmpl, sp->x[idx].xvec, family))
return ++idx;
if (sp->x[idx].xvec->props.mode)
break;
}
return start;
}
static int
_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
afinfo->decode_session(skb, fl);
xfrm_policy_put_afinfo(afinfo);
return 0;
}
static inline int secpath_has_tunnel(struct sec_path *sp, int k)
{
for (; k < sp->len; k++) {
if (sp->x[k].xvec->props.mode)
return 1;
}
return 0;
}
int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
unsigned short family)
{
struct xfrm_policy *pol;
struct flowi fl;
if (_decode_session(skb, &fl, family) < 0)
return 0;
/* First, check used SA against their selectors. */
if (skb->sp) {
int i;
for (i=skb->sp->len-1; i>=0; i--) {
struct sec_decap_state *xvec = &(skb->sp->x[i]);
if (!xfrm_selector_match(&xvec->xvec->sel, &fl, family))
return 0;
/* If there is a post_input processor, try running it */
if (xvec->xvec->type->post_input &&
(xvec->xvec->type->post_input)(xvec->xvec,
&(xvec->decap),
skb) != 0)
return 0;
}
}
pol = NULL;
if (sk && sk->sk_policy[dir])
pol = xfrm_sk_policy_lookup(sk, dir, &fl);
if (!pol)
pol = flow_cache_lookup(&fl, family,
policy_to_flow_dir(dir),
xfrm_policy_lookup);
if (!pol)
return !skb->sp || !secpath_has_tunnel(skb->sp, 0);
pol->curlft.use_time = (unsigned long)xtime.tv_sec;
if (pol->action == XFRM_POLICY_ALLOW) {
struct sec_path *sp;
static struct sec_path dummy;
int i, k;
if ((sp = skb->sp) == NULL)
sp = &dummy;
/* For each tunnel xfrm, find the first matching tmpl.
* For each tmpl before that, find corresponding xfrm.
* Order is _important_. Later we will implement
* some barriers, but at the moment barriers
* are implied between each two transformations.
*/
for (i = pol->xfrm_nr-1, k = 0; i >= 0; i--) {
k = xfrm_policy_ok(pol->xfrm_vec+i, sp, k, family);
if (k < 0)
goto reject;
}
if (secpath_has_tunnel(sp, k))
goto reject;
xfrm_pol_put(pol);
return 1;
}
reject:
xfrm_pol_put(pol);
return 0;
}
EXPORT_SYMBOL(__xfrm_policy_check);
int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
{
struct flowi fl;
if (_decode_session(skb, &fl, family) < 0)
return 0;
return xfrm_lookup(&skb->dst, &fl, NULL, 0) == 0;
}
EXPORT_SYMBOL(__xfrm_route_forward);
/* Optimize later using cookies and generation ids. */
static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
{
if (!stale_bundle(dst))
return dst;
return NULL;
}
static int stale_bundle(struct dst_entry *dst)
{
return !xfrm_bundle_ok((struct xfrm_dst *)dst, NULL, AF_UNSPEC);
}
void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
{
while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
dst->dev = &loopback_dev;
dev_hold(&loopback_dev);
dev_put(dev);
}
}
EXPORT_SYMBOL(xfrm_dst_ifdown);
static void xfrm_link_failure(struct sk_buff *skb)
{
/* Impossible. Such dst must be popped before reaches point of failure. */
return;
}
static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
{
if (dst) {
if (dst->obsolete) {
dst_release(dst);
dst = NULL;
}
}
return dst;
}
static void xfrm_prune_bundles(int (*func)(struct dst_entry *))
{
int i;
struct xfrm_policy *pol;
struct dst_entry *dst, **dstp, *gc_list = NULL;
read_lock_bh(&xfrm_policy_lock);
for (i=0; i<2*XFRM_POLICY_MAX; i++) {
for (pol = xfrm_policy_list[i]; pol; pol = pol->next) {
write_lock(&pol->lock);
dstp = &pol->bundles;
while ((dst=*dstp) != NULL) {
if (func(dst)) {
*dstp = dst->next;
dst->next = gc_list;
gc_list = dst;
} else {
dstp = &dst->next;
}
}
write_unlock(&pol->lock);
}
}
read_unlock_bh(&xfrm_policy_lock);
while (gc_list) {
dst = gc_list;
gc_list = dst->next;
dst_free(dst);
}
}
static int unused_bundle(struct dst_entry *dst)
{
return !atomic_read(&dst->__refcnt);
}
static void __xfrm_garbage_collect(void)
{
xfrm_prune_bundles(unused_bundle);
}
int xfrm_flush_bundles(void)
{
xfrm_prune_bundles(stale_bundle);
return 0;
}
void xfrm_init_pmtu(struct dst_entry *dst)
{
do {
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
u32 pmtu, route_mtu_cached;
pmtu = dst_mtu(dst->child);
xdst->child_mtu_cached = pmtu;
pmtu = xfrm_state_mtu(dst->xfrm, pmtu);
route_mtu_cached = dst_mtu(xdst->route);
xdst->route_mtu_cached = route_mtu_cached;
if (pmtu > route_mtu_cached)
pmtu = route_mtu_cached;
dst->metrics[RTAX_MTU-1] = pmtu;
} while ((dst = dst->next));
}
EXPORT_SYMBOL(xfrm_init_pmtu);
/* Check that the bundle accepts the flow and its components are
* still valid.
*/
int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family)
{
struct dst_entry *dst = &first->u.dst;
struct xfrm_dst *last;
u32 mtu;
if (!dst_check(dst->path, ((struct xfrm_dst *)dst)->path_cookie) ||
(dst->dev && !netif_running(dst->dev)))
return 0;
last = NULL;
do {
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
return 0;
if (dst->xfrm->km.state != XFRM_STATE_VALID)
return 0;
mtu = dst_mtu(dst->child);
if (xdst->child_mtu_cached != mtu) {
last = xdst;
xdst->child_mtu_cached = mtu;
}
if (!dst_check(xdst->route, xdst->route_cookie))
return 0;
mtu = dst_mtu(xdst->route);
if (xdst->route_mtu_cached != mtu) {
last = xdst;
xdst->route_mtu_cached = mtu;
}
dst = dst->child;
} while (dst->xfrm);
if (likely(!last))
return 1;
mtu = last->child_mtu_cached;
for (;;) {
dst = &last->u.dst;
mtu = xfrm_state_mtu(dst->xfrm, mtu);
if (mtu > last->route_mtu_cached)
mtu = last->route_mtu_cached;
dst->metrics[RTAX_MTU-1] = mtu;
if (last == first)
break;
last = last->u.next;
last->child_mtu_cached = mtu;
}
return 1;
}
EXPORT_SYMBOL(xfrm_bundle_ok);
/* Well... that's _TASK_. We need to scan through transformation
* list and figure out what mss tcp should generate in order to
* final datagram fit to mtu. Mama mia... :-)
*
* Apparently, some easy way exists, but we used to choose the most
* bizarre ones. :-) So, raising Kalashnikov... tra-ta-ta.
*
* Consider this function as something like dark humour. :-)
*/
static int xfrm_get_mss(struct dst_entry *dst, u32 mtu)
{
int res = mtu - dst->header_len;
for (;;) {
struct dst_entry *d = dst;
int m = res;
do {
struct xfrm_state *x = d->xfrm;
if (x) {
spin_lock_bh(&x->lock);
if (x->km.state == XFRM_STATE_VALID &&
x->type && x->type->get_max_size)
m = x->type->get_max_size(d->xfrm, m);
else
m += x->props.header_len;
spin_unlock_bh(&x->lock);
}
} while ((d = d->child) != NULL);
if (m <= mtu)
break;
res -= (m - mtu);
if (res < 88)
return mtu;
}
return res + dst->header_len;
}
int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
{
int err = 0;
if (unlikely(afinfo == NULL))
return -EINVAL;
if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT;
write_lock(&xfrm_policy_afinfo_lock);
if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
err = -ENOBUFS;
else {
struct dst_ops *dst_ops = afinfo->dst_ops;
if (likely(dst_ops->kmem_cachep == NULL))
dst_ops->kmem_cachep = xfrm_dst_cache;
if (likely(dst_ops->check == NULL))
dst_ops->check = xfrm_dst_check;
if (likely(dst_ops->negative_advice == NULL))
dst_ops->negative_advice = xfrm_negative_advice;
if (likely(dst_ops->link_failure == NULL))
dst_ops->link_failure = xfrm_link_failure;
if (likely(dst_ops->get_mss == NULL))
dst_ops->get_mss = xfrm_get_mss;
if (likely(afinfo->garbage_collect == NULL))
afinfo->garbage_collect = __xfrm_garbage_collect;
xfrm_policy_afinfo[afinfo->family] = afinfo;
}
write_unlock(&xfrm_policy_afinfo_lock);
return err;
}
EXPORT_SYMBOL(xfrm_policy_register_afinfo);
int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
{
int err = 0;
if (unlikely(afinfo == NULL))
return -EINVAL;
if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT;
write_lock(&xfrm_policy_afinfo_lock);
if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
err = -EINVAL;
else {
struct dst_ops *dst_ops = afinfo->dst_ops;
xfrm_policy_afinfo[afinfo->family] = NULL;
dst_ops->kmem_cachep = NULL;
dst_ops->check = NULL;
dst_ops->negative_advice = NULL;
dst_ops->link_failure = NULL;
dst_ops->get_mss = NULL;
afinfo->garbage_collect = NULL;
}
}
write_unlock(&xfrm_policy_afinfo_lock);
return err;
}
EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
{
struct xfrm_policy_afinfo *afinfo;
if (unlikely(family >= NPROTO))
return NULL;
read_lock(&xfrm_policy_afinfo_lock);
afinfo = xfrm_policy_afinfo[family];
if (likely(afinfo != NULL))
read_lock(&afinfo->lock);
read_unlock(&xfrm_policy_afinfo_lock);
return afinfo;
}
static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
{
if (unlikely(afinfo == NULL))
return;
read_unlock(&afinfo->lock);
}
static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
switch (event) {
case NETDEV_DOWN:
xfrm_flush_bundles();
}
return NOTIFY_DONE;
}
static struct notifier_block xfrm_dev_notifier = {
xfrm_dev_event,
NULL,
0
};
static void __init xfrm_policy_init(void)
{
xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
sizeof(struct xfrm_dst),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (!xfrm_dst_cache)
panic("XFRM: failed to allocate xfrm_dst_cache\n");
INIT_WORK(&xfrm_policy_gc_work, xfrm_policy_gc_task, NULL);
register_netdevice_notifier(&xfrm_dev_notifier);
}
void __init xfrm_init(void)
{
xfrm_state_init();
xfrm_policy_init();
xfrm_input_init();
}
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