@@ -28,7 +28,8 @@ struct mpls_route { /* next hop label forwarding entry */
struct rcu_head rt_rcu;
u32 rt_label[MAX_NEW_LABELS];
u8 rt_protocol; /* routing protocol that set this entry */
- u8 rt_labels;
+ u8 rt_unlabeled : 1;
+ u8 rt_labels : 7;
u8 rt_via_alen;
u8 rt_via_table;
u8 rt_via[0];
@@ -201,6 +202,11 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
if (unlikely(!new_header_size && dec.bos)) {
if (!mpls_egress(rt, skb, dec))
goto drop;
+ } else if (rt->rt_unlabeled) {
+ /* Labeled traffic destined to unlabeled peer should
+ * be discarded
+ */
+ goto drop;
} else {
bool bos;
int i;
@@ -385,9 +391,16 @@ static int mpls_route_add(struct mpls_route_config *cfg)
if (!rt)
goto errout;
- rt->rt_labels = cfg->rc_output_labels;
- for (i = 0; i < rt->rt_labels; i++)
- rt->rt_label[i] = cfg->rc_output_label[i];
+ if (cfg->rc_output_labels == 1 &&
+ cfg->rc_output_label[0] == LABEL_IMPLICIT_NULL) {
+ rt->rt_labels = 0;
+ } else {
+ rt->rt_labels = cfg->rc_output_labels;
+ for (i = 0; i < rt->rt_labels; i++)
+ rt->rt_label[i] = cfg->rc_output_label[i];
+ if (!rt->rt_labels)
+ rt->rt_unlabeled = true;
+ }
rt->rt_protocol = cfg->rc_protocol;
RCU_INIT_POINTER(rt->rt_dev, dev);
rt->rt_via_table = cfg->rc_via_table;
The control plane can advertise labels for neighbours that don't have an outgoing label. RFC 3032 s3.22 states that either the remaining labels should be popped (if the control plane can determine that it's safe to do so, which in light of MPLS-VPN, RFC 4364, is never the case now) or that the packet should be discarded. Therefore, if the peer is unlabeled and the last label wasn't popped then drop the packet. The peer being unlabeled is signalled by an empty label stack. However, implicit-null still needs to be supported (i.e. penultimate hop popping) where the incoming label is popped and no labels are put on and the packet can still go out labeled with the unpopped part of the stack. This is achieved by the control plane specifying a label stack consisting of the single special implicit-null value. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> --- net/mpls/af_mpls.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)