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-rw-r--r--net/l2tp/l2tp_core.c36
-rw-r--r--net/l2tp/l2tp_core.h3
2 files changed, 34 insertions, 5 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 735cc06971ef..feae495a0a30 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -572,12 +572,33 @@ static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
* reorder queue, in order of ns.
*/
l2tp_recv_queue_skb(session, skb);
+ goto out;
+ }
+
+ /* Packet reordering disabled. Discard out-of-sequence packets, while
+ * tracking the number if in-sequence packets after the first OOS packet
+ * is seen. After nr_oos_count_max in-sequence packets, reset the
+ * sequence number to re-enable packet reception.
+ */
+ if (L2TP_SKB_CB(skb)->ns == session->nr) {
+ skb_queue_tail(&session->reorder_q, skb);
} else {
- /* Packet reordering disabled. Discard out-of-sequence
- * packets
- */
- if ((L2TP_SKB_CB(skb)->ns != session->nr) &&
- (!session->reorder_skip)) {
+ u32 nr_oos = L2TP_SKB_CB(skb)->ns;
+ u32 nr_next = (session->nr_oos + 1) & session->nr_max;
+
+ if (nr_oos == nr_next)
+ session->nr_oos_count++;
+ else
+ session->nr_oos_count = 0;
+
+ session->nr_oos = nr_oos;
+ if (session->nr_oos_count > session->nr_oos_count_max) {
+ session->reorder_skip = 1;
+ l2tp_dbg(session, L2TP_MSG_SEQ,
+ "%s: %d oos packets received. Resetting sequence numbers\n",
+ session->name, session->nr_oos_count);
+ }
+ if (!session->reorder_skip) {
atomic_long_inc(&session->stats.rx_seq_discards);
l2tp_dbg(session, L2TP_MSG_SEQ,
"%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
@@ -589,6 +610,7 @@ static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
skb_queue_tail(&session->reorder_q, skb);
}
+out:
return 0;
discard:
@@ -1852,6 +1874,10 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
else
session->nr_max = 0xffffff;
session->nr_window_size = session->nr_max / 2;
+ session->nr_oos_count_max = 4;
+
+ /* Use NR of first received packet */
+ session->reorder_skip = 1;
sprintf(&session->name[0], "sess %u/%u",
tunnel->tunnel_id, session->session_id);
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 4b9a3b724423..66a559b104b6 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -104,6 +104,9 @@ struct l2tp_session {
struct sk_buff_head reorder_q; /* receive reorder queue */
u32 nr_max; /* max NR. Depends on tunnel */
u32 nr_window_size; /* NR window size */
+ u32 nr_oos; /* NR of last OOS packet */
+ int nr_oos_count; /* For OOS recovery */
+ int nr_oos_count_max;
struct hlist_node hlist; /* Hash list node */
atomic_t ref_count;