l2tp: add session reorder queue purge function to core

If an l2tp session is deleted, it is necessary to delete skbs in-flight
on the session's reorder queue before taking it down.

Rather than having each pseudowire implementation reaching into the
l2tp_session struct to handle this itself, provide a function in l2tp_core to
purge the session queue.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 18 insertions, 0 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index e841ef2a68a5..69c316dd02dc 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -829,6 +829,23 @@ discard:
 }
 EXPORT_SYMBOL(l2tp_recv_common);
 
+/* Drop skbs from the session's reorder_q
+ */
+int l2tp_session_queue_purge(struct l2tp_session *session)
+{
+        struct sk_buff *skb = NULL;
+        BUG_ON(!session);
+        BUG_ON(session->magic != L2TP_SESSION_MAGIC);
+        while ((skb = skb_dequeue(&session->reorder_q))) {
+                atomic_long_inc(&session->stats.rx_errors);
+                kfree_skb(skb);
+                if (session->deref)
+                        (*session->deref)(session);
+        }
+        return 0;
+}
+EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
+
 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
  * here. The skb is not on a list when we get here.
  * Returns 0 if the packet was a data packet and was successfully passed on.
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index b0861f68a10b..d40713d105fc 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -246,6 +246,7 @@ extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunne
 extern int l2tp_session_delete(struct l2tp_session *session);
 extern void l2tp_session_free(struct l2tp_session *session);
 extern void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length, int (*payload_hook)(struct sk_buff *skb));
+extern int l2tp_session_queue_purge(struct l2tp_session *session);
 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 
 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);