l2tp: fix userspace reception on plain L2TP sockets

As pppol2tp_recv() never queues up packets to plain L2TP sockets,
pppol2tp_recvmsg() never returns data to userspace, thus making
the recv*() system calls unusable.

Instead of dropping packets when the L2TP socket isn't bound to a PPP
channel, this patch adds them to its reception queue.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 5 deletions

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 6bfeaa777135..5990919356a5 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -254,12 +254,14 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int
                 po = pppox_sk(sk);
                 ppp_input(&po->chan, skb);
         } else {
-                l2tp_info(session, PPPOL2TP_MSG_DATA, "%s: socket not bound\n",
-                          session->name);
+                l2tp_dbg(session, PPPOL2TP_MSG_DATA,
+                         "%s: recv %d byte data frame, passing to L2TP socket\n",
+                         session->name, data_len);
 
-                /* Not bound. Nothing we can do, so discard. */
-                atomic_long_inc(&session->stats.rx_errors);
-                kfree_skb(skb);
+                if (sock_queue_rcv_skb(sk, skb) < 0) {
+                        atomic_long_inc(&session->stats.rx_errors);
+                        kfree_skb(skb);
+                }
         }
 
         return;