diff options
Diffstat (limited to 'net/l2tp/l2tp_core.c')
| -rw-r--r-- | net/l2tp/l2tp_core.c | 37 |
1 files changed, 30 insertions, 7 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 8d21ff25f160..7d519a46a844 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; @@ -819,13 +820,8 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) /* Get L2TP header flags */ hdrflags = ntohs(*(__be16 *)ptr); - /* Check protocol version */ + /* Get protocol version */ version = hdrflags & L2TP_HDR_VER_MASK; - if (version != tunnel->version) { - pr_debug_ratelimited("%s: recv protocol version mismatch: got %d expected %d\n", - tunnel->name, version, tunnel->version); - goto invalid; - } /* Get length of L2TP packet */ length = skb->len; @@ -837,7 +833,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) /* Skip flags */ ptr += 2; - if (tunnel->version == L2TP_HDR_VER_2) { + if (version == L2TP_HDR_VER_2) { /* If length is present, skip it */ if (hdrflags & L2TP_HDRFLAG_L) ptr += 2; @@ -845,6 +841,20 @@ 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) + goto pass; + tunnel = alt_tunnel; + } + session_id = ntohs(*(__be16 *)ptr); ptr += 2; } else { @@ -854,6 +864,13 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb) ptr += 4; } + /* Check protocol version */ + if (version != tunnel->version) { + pr_debug_ratelimited("%s: recv protocol version mismatch: got %d expected %d\n", + tunnel->name, version, tunnel->version); + goto invalid; + } + /* Find the session context */ session = l2tp_tunnel_get_session(tunnel, session_id); if (!session || !session->recv_skb) { @@ -875,6 +892,9 @@ 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 +904,9 @@ pass: /* Put UDP header back */ __skb_push(skb, sizeof(struct udphdr)); + if (tunnel != orig_tunnel) + l2tp_tunnel_dec_refcount(tunnel); + return 1; } |