xfrm: Add a state resolution packet queue
As the default, we blackhole packets until the key manager resolves
the states. This patch implements a packet queue where IPsec packets
are queued until the states are resolved. We generate a dummy xfrm
bundle, the output routine of the returned route enqueues the packet
to a per policy queue and arms a timer that checks for state resolution
when dst_output() is called. Once the states are resolved, the packets
are sent out of the queue. If the states are not resolved after some
time, the queue is flushed.
This patch keeps the defaut behaviour to blackhole packets as long
as we have no states. To enable the packet queue the sysctl
xfrm_larval_drop must be switched off.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 41eabc4..456b11b 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -35,6 +35,10 @@
#include "xfrm_hash.h"
+#define XFRM_QUEUE_TMO_MIN ((unsigned)(HZ/10))
+#define XFRM_QUEUE_TMO_MAX ((unsigned)(60*HZ))
+#define XFRM_MAX_QUEUE_LEN 100
+
DEFINE_MUTEX(xfrm_cfg_mutex);
EXPORT_SYMBOL(xfrm_cfg_mutex);
@@ -51,7 +55,7 @@
static void xfrm_init_pmtu(struct dst_entry *dst);
static int stale_bundle(struct dst_entry *dst);
static int xfrm_bundle_ok(struct xfrm_dst *xdst);
-
+static void xfrm_policy_queue_process(unsigned long arg);
static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
int dir);
@@ -287,8 +291,11 @@
INIT_HLIST_NODE(&policy->byidx);
rwlock_init(&policy->lock);
atomic_set(&policy->refcnt, 1);
+ skb_queue_head_init(&policy->polq.hold_queue);
setup_timer(&policy->timer, xfrm_policy_timer,
(unsigned long)policy);
+ setup_timer(&policy->polq.hold_timer, xfrm_policy_queue_process,
+ (unsigned long)policy);
policy->flo.ops = &xfrm_policy_fc_ops;
}
return policy;
@@ -309,6 +316,16 @@
}
EXPORT_SYMBOL(xfrm_policy_destroy);
+static void xfrm_queue_purge(struct sk_buff_head *list)
+{
+ struct sk_buff *skb;
+
+ while ((skb = skb_dequeue(list)) != NULL) {
+ dev_put(skb->dev);
+ kfree_skb(skb);
+ }
+}
+
/* Rule must be locked. Release descentant resources, announce
* entry dead. The rule must be unlinked from lists to the moment.
*/
@@ -319,6 +336,9 @@
atomic_inc(&policy->genid);
+ del_timer(&policy->polq.hold_timer);
+ xfrm_queue_purge(&policy->polq.hold_queue);
+
if (del_timer(&policy->timer))
xfrm_pol_put(policy);
@@ -562,6 +582,31 @@
return 0;
}
+static void xfrm_policy_requeue(struct xfrm_policy *old,
+ struct xfrm_policy *new)
+{
+ struct xfrm_policy_queue *pq = &old->polq;
+ struct sk_buff_head list;
+
+ __skb_queue_head_init(&list);
+
+ spin_lock_bh(&pq->hold_queue.lock);
+ skb_queue_splice_init(&pq->hold_queue, &list);
+ del_timer(&pq->hold_timer);
+ spin_unlock_bh(&pq->hold_queue.lock);
+
+ if (skb_queue_empty(&list))
+ return;
+
+ pq = &new->polq;
+
+ spin_lock_bh(&pq->hold_queue.lock);
+ skb_queue_splice(&list, &pq->hold_queue);
+ pq->timeout = XFRM_QUEUE_TMO_MIN;
+ mod_timer(&pq->hold_timer, jiffies);
+ spin_unlock_bh(&pq->hold_queue.lock);
+}
+
int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
{
struct net *net = xp_net(policy);
@@ -603,8 +648,10 @@
net->xfrm.policy_count[dir]++;
atomic_inc(&flow_cache_genid);
rt_genid_bump(net);
- if (delpol)
+ if (delpol) {
+ xfrm_policy_requeue(delpol, policy);
__xfrm_policy_unlink(delpol, dir);
+ }
policy->index = delpol ? delpol->index : xfrm_gen_index(net, dir);
hlist_add_head(&policy->byidx, net->xfrm.policy_byidx+idx_hash(net, policy->index));
policy->curlft.add_time = get_seconds();
@@ -1115,11 +1162,15 @@
pol->index = xfrm_gen_index(net, XFRM_POLICY_MAX+dir);
__xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
}
- if (old_pol)
+ if (old_pol) {
+ if (pol)
+ xfrm_policy_requeue(old_pol, pol);
+
/* Unlinking succeeds always. This is the only function
* allowed to delete or replace socket policy.
*/
__xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
+ }
write_unlock_bh(&xfrm_policy_lock);
if (old_pol) {
@@ -1310,6 +1361,8 @@
* It means we need to try again resolving. */
if (xdst->num_xfrms > 0)
return NULL;
+ } else if (dst->flags & DST_XFRM_QUEUE) {
+ return NULL;
} else {
/* Real bundle */
if (stale_bundle(dst))
@@ -1673,6 +1726,171 @@
return xdst;
}
+static void xfrm_policy_queue_process(unsigned long arg)
+{
+ int err = 0;
+ struct sk_buff *skb;
+ struct sock *sk;
+ struct dst_entry *dst;
+ struct net_device *dev;
+ struct xfrm_policy *pol = (struct xfrm_policy *)arg;
+ struct xfrm_policy_queue *pq = &pol->polq;
+ struct flowi fl;
+ struct sk_buff_head list;
+
+ spin_lock(&pq->hold_queue.lock);
+ skb = skb_peek(&pq->hold_queue);
+ dst = skb_dst(skb);
+ sk = skb->sk;
+ xfrm_decode_session(skb, &fl, dst->ops->family);
+ spin_unlock(&pq->hold_queue.lock);
+
+ dst_hold(dst->path);
+ dst = xfrm_lookup(xp_net(pol), dst->path, &fl,
+ sk, 0);
+ if (IS_ERR(dst))
+ goto purge_queue;
+
+ if (dst->flags & DST_XFRM_QUEUE) {
+ dst_release(dst);
+
+ if (pq->timeout >= XFRM_QUEUE_TMO_MAX)
+ goto purge_queue;
+
+ pq->timeout = pq->timeout << 1;
+ mod_timer(&pq->hold_timer, jiffies + pq->timeout);
+ return;
+ }
+
+ dst_release(dst);
+
+ __skb_queue_head_init(&list);
+
+ spin_lock(&pq->hold_queue.lock);
+ pq->timeout = 0;
+ skb_queue_splice_init(&pq->hold_queue, &list);
+ spin_unlock(&pq->hold_queue.lock);
+
+ while (!skb_queue_empty(&list)) {
+ skb = __skb_dequeue(&list);
+
+ xfrm_decode_session(skb, &fl, skb_dst(skb)->ops->family);
+ dst_hold(skb_dst(skb)->path);
+ dst = xfrm_lookup(xp_net(pol), skb_dst(skb)->path,
+ &fl, skb->sk, 0);
+ if (IS_ERR(dst)) {
+ dev_put(skb->dev);
+ kfree_skb(skb);
+ continue;
+ }
+
+ nf_reset(skb);
+ skb_dst_drop(skb);
+ skb_dst_set(skb, dst);
+
+ dev = skb->dev;
+ err = dst_output(skb);
+ dev_put(dev);
+ }
+
+ return;
+
+purge_queue:
+ pq->timeout = 0;
+ xfrm_queue_purge(&pq->hold_queue);
+}
+
+static int xdst_queue_output(struct sk_buff *skb)
+{
+ unsigned long sched_next;
+ struct dst_entry *dst = skb_dst(skb);
+ struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
+ struct xfrm_policy_queue *pq = &xdst->pols[0]->polq;
+
+ if (pq->hold_queue.qlen > XFRM_MAX_QUEUE_LEN) {
+ kfree_skb(skb);
+ return -EAGAIN;
+ }
+
+ skb_dst_force(skb);
+ dev_hold(skb->dev);
+
+ spin_lock_bh(&pq->hold_queue.lock);
+
+ if (!pq->timeout)
+ pq->timeout = XFRM_QUEUE_TMO_MIN;
+
+ sched_next = jiffies + pq->timeout;
+
+ if (del_timer(&pq->hold_timer)) {
+ if (time_before(pq->hold_timer.expires, sched_next))
+ sched_next = pq->hold_timer.expires;
+ }
+
+ __skb_queue_tail(&pq->hold_queue, skb);
+ mod_timer(&pq->hold_timer, sched_next);
+
+ spin_unlock_bh(&pq->hold_queue.lock);
+
+ return 0;
+}
+
+static struct xfrm_dst *xfrm_create_dummy_bundle(struct net *net,
+ struct dst_entry *dst,
+ const struct flowi *fl,
+ int num_xfrms,
+ u16 family)
+{
+ int err;
+ struct net_device *dev;
+ struct dst_entry *dst1;
+ struct xfrm_dst *xdst;
+
+ xdst = xfrm_alloc_dst(net, family);
+ if (IS_ERR(xdst))
+ return xdst;
+
+ if (net->xfrm.sysctl_larval_drop || num_xfrms <= 0 ||
+ (fl->flowi_flags & FLOWI_FLAG_CAN_SLEEP))
+ return xdst;
+
+ dst1 = &xdst->u.dst;
+ dst_hold(dst);
+ xdst->route = dst;
+
+ dst_copy_metrics(dst1, dst);
+
+ dst1->obsolete = DST_OBSOLETE_FORCE_CHK;
+ dst1->flags |= DST_HOST | DST_XFRM_QUEUE;
+ dst1->lastuse = jiffies;
+
+ dst1->input = dst_discard;
+ dst1->output = xdst_queue_output;
+
+ dst_hold(dst);
+ dst1->child = dst;
+ dst1->path = dst;
+
+ xfrm_init_path((struct xfrm_dst *)dst1, dst, 0);
+
+ err = -ENODEV;
+ dev = dst->dev;
+ if (!dev)
+ goto free_dst;
+
+ err = xfrm_fill_dst(xdst, dev, fl);
+ if (err)
+ goto free_dst;
+
+out:
+ return xdst;
+
+free_dst:
+ dst_release(dst1);
+ xdst = ERR_PTR(err);
+ goto out;
+}
+
static struct flow_cache_object *
xfrm_bundle_lookup(struct net *net, const struct flowi *fl, u16 family, u8 dir,
struct flow_cache_object *oldflo, void *ctx)
@@ -1751,7 +1969,7 @@
/* We found policies, but there's no bundles to instantiate:
* either because the policy blocks, has no transformations or
* we could not build template (no xfrm_states).*/
- xdst = xfrm_alloc_dst(net, family);
+ xdst = xfrm_create_dummy_bundle(net, dst_orig, fl, num_xfrms, family);
if (IS_ERR(xdst)) {
xfrm_pols_put(pols, num_pols);
return ERR_CAST(xdst);
@@ -2359,6 +2577,9 @@
(dst->dev && !netif_running(dst->dev)))
return 0;
+ if (dst->flags & DST_XFRM_QUEUE)
+ return 1;
+
last = NULL;
do {