diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 8d21ff25f160..2ab45e3f48bf 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -794,6 +794,7 @@ static void l2tp_session_queue_purge(struct l2tp_session *session) static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) { struct l2tp_session *session = NULL; + struct l2tp_tunnel *orig_tunnel = tunnel; unsigned char *ptr, *optr; u16 hdrflags; u32 tunnel_id, session_id; @@ -845,6 +846,20 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) /* Extract tunnel and session ID */ tunnel_id = ntohs(*(__be16 *)ptr); ptr += 2; + + if (tunnel_id != tunnel->tunnel_id) { + /* We are receiving trafic for another tunnel, probably + * because we have several tunnels between the same + * IP/port quadruple, look it up. + */ + struct l2tp_tunnel *alt_tunnel; + + alt_tunnel = l2tp_tunnel_get(tunnel->l2tp_net, tunnel_id); + if (!alt_tunnel || alt_tunnel->version != L2TP_HDR_VER_2) + goto pass; + tunnel = alt_tunnel; + } + session_id = ntohs(*(__be16 *)ptr); ptr += 2; } else { @@ -875,6 +890,9 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) l2tp_recv_common(session, skb, ptr, optr, hdrflags, length); l2tp_session_dec_refcount(session); + if (tunnel != orig_tunnel) + l2tp_tunnel_dec_refcount(tunnel); + return 0; invalid: @@ -884,6 +902,9 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) /* Put UDP header back */ __skb_push(skb, sizeof(struct udphdr)); + if (tunnel != orig_tunnel) + l2tp_tunnel_dec_refcount(tunnel); + return 1; }