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linux/net/xfrm/xfrm_policy.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

1368 lines
30 KiB
C
Raw Blame History

/*
* 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);
km_policy_expired(xp, dir, 1);
xfrm_policy_delete(xp, dir);
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;
}
void 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);
}
}
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);
}
static void xfrm_dst_destroy(struct dst_entry *dst)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
dst_release(xdst->route);
if (!dst->xfrm)
return;
xfrm_state_put(dst->xfrm);
dst->xfrm = NULL;
}
static void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
if (!unregister)
return;
while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
dst->dev = &loopback_dev;
dev_hold(&loopback_dev);
dev_put(dev);
}
}
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, 0) ||
(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, 0))
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->destroy == NULL))
dst_ops->destroy = xfrm_dst_destroy;
if (likely(dst_ops->ifdown == NULL))
dst_ops->ifdown = xfrm_dst_ifdown;
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->destroy = NULL;
dst_ops->ifdown = 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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