[ovs-dev] [PATCH v12 6/8] Always update ethertype on mpls_pop

Simon Horman horms at verge.net.au
Wed Jun 5 05:28:52 UTC 2013

The ethertype should always be updated on mpls_pop
as there may be a transition between MPLS unicast (0x8847) and
MPLS multicast (0x8848).

Ben Pfaff tells me that this is consistent with the
behaviour described in EXT-194 of the JIRA bug tracker.

Signed-off-by: Simon Horman <horms+renesas at verge.net.au>


* Rebse

* Include in recirculation patch-set

v3 - v10
* Not posted

* Add note about EXT-194 to changelog
* Update manpage. Note that I plan to post a patch to
  make use of recirculation to remove restrictions on
  the use of MPLS pop and push.
 lib/packets.c            | 3 +--
 utilities/ovs-ofctl.8.in | 7 ++++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/packets.c b/lib/packets.c
index 77aa7d3..f2e0f81 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -373,9 +373,8 @@ pop_mpls(struct ofpbuf *packet, ovs_be16 ethtype)
         size_t len;
         mh = packet->l2_5;
         len = (char*)packet->l2_5 - (char*)packet->l2;
-        /* If bottom of the stack set ethertype. */
+        set_ethertype(packet, ethtype);
         if (mh->mpls_lse & htonl(MPLS_BOS_MASK)) {
-            set_ethertype(packet, ethtype);
             packet->l2_5 = NULL;
         } else {
             packet->l2_5 = (char*)packet->l2_5 + MPLS_HLEN;
diff --git a/utilities/ovs-ofctl.8.in b/utilities/ovs-ofctl.8.in
index 061982b..e66c605 100644
--- a/utilities/ovs-ofctl.8.in
+++ b/utilities/ovs-ofctl.8.in
@@ -944,9 +944,10 @@ followed by another \fBpush_mpls\fR will result in the first
 \fBpush_mpls\fR being discarded.
 .IP \fBpop_mpls\fR:\fIethertype\fR
-Strips the outermost MPLS label stack entry.  If the MPLS label
-stripped was the only one, changes the ethertype of a packet to
-\fIethertype\fR, which should not ordinarily be an MPLS Ethertype.
+Strips the outermost MPLS label stack entry.
+Currently the implementation restricts \fIethertype\fR to a non-MPLS Ethertype
+and thus \fBpop_mpls\fR should only be applied to packets with
+an MPLS label stack depth of one.
 There are some limitations in the implementation.  \fBpop_mpls\fR

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