[PATCH 3.2 14/79] l2tp: add session reorder queue purge function to core

Ben Hutchings
2018-02-11T04:33:40Z

From: Tom Parkin <tparkin@katalix.com>

commit 48f72f92b31431c40279b0fba6c5588e07e67d95 upstream.

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>
[bwh: Backported to 3.2: use non-atomic increment on rx_errors]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/l2tp/l2tp_core.c | 17 +++++++++++++++++
net/l2tp/l2tp_core.h | 1 +
2 files changed, 18 insertions(+)

--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -830,6 +830,23 @@ 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))) {
+ 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.
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -249,6 +249,7 @@ extern struct l2tp_session *l2tp_session
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);