On 7/26/15 9:57 AM, ravulakollu.ku...@wipro.com wrote:
Hi Thomas,

I am currently using the beta version of ovs(2.3.90). In my phy-phy scenario  , 
I am configuring the two physical ports(eth0, eth1) attached to ovs bridge
as trunk ports using the below commands.

ovs-vsctl --no-wait add-port br0 eth0 vlan_mode=trunk
ovs-vsctl --no-wait add-port br0 eth1 vlan_mode=trunk

I configured the bridge to work in legacy mode as shown below

$ ovs-ofctl dump-flows br0
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=15.458s, table=0, n_packets=0, n_bytes=0, idle_age=15, 
priority=0 actions=NORMAL

I tried sending 802.1ad tagged(outer tag tpid=0x88a8, inter tag tpid=ox8100) 
packet from packetgen to phyport1 (eth0), and receiving back on phyport2(eth2).
When I captured the received packet on eth1 , the received packet is not same 
as sent packet, means outer vlan TPID is not 0x88a8(instead 0x8100).

This patch supports pushing and popping of double tagged vlans. It shouldn't affect double tagged traffic flowing through the switch unless your ovs bridge has flows to pop or push a vlan.

Are you using tcpdump to look at the packets? There is a bug in libpcap where the outer TPID of outgoing packets is miss-reported as 0x8100 whether or not the tpid is actually 0x88a8

Could you please let me know , whether the below mentioned patch helps here.

Thanks in Advance,
Uday

-----Original Message-----
From: dev [mailto:dev-boun...@openvswitch.org] On Behalf Of Thomas F Herbert
Sent: Sunday, July 26, 2015 6:03 AM
To: Pravin Shelar
Cc: d...@openvswitch.org; netdev; therb...@redhat.com
Subject: Re: [ovs-dev] [PATCH net-next 3/3] openvswitch: 802.1AD: Flow 
handling, actions, and vlan parsing

On 6/30/15 12:16 AM, Pravin Shelar wrote:
On Tue, Jun 23, 2015 at 11:26 AM, Thomas F Herbert
Pravin, I apologize because I realize now that I am finishing V12 of this patch 
that I never responded to your comments in this email.
<thomasfherb...@gmail.com> wrote:
Add support for 802.1ad including the ability to push and pop double
tagged vlans. Add support for 802.1ad to netlink parsing and flow
conversion. Uses double nested encap attributes to represent double
tagged vlan. Inner TPID encoded along with ctci in nested attributes.

Signed-off-by: Thomas F Herbert <thomasfherb...@gmail.com>
---
   net/openvswitch/flow.c         |  84 +++++++++++++++---
   net/openvswitch/flow.h         |   5 ++
   net/openvswitch/flow_netlink.c | 195 
++++++++++++++++++++++++++++++++++-------
   3 files changed, 242 insertions(+), 42 deletions(-)

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c index
2dacc7b..e268865 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -298,21 +298,80 @@ static bool icmp6hdr_ok(struct sk_buff *skb)
   static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
   {
          struct qtag_prefix {
-               __be16 eth_type; /* ETH_P_8021Q */
+               __be16 eth_type; /* ETH_P_8021Q  or ETH_P_8021AD */
                  __be16 tci;
          };
-       struct qtag_prefix *qp;
+       struct qtag_prefix *qp = (struct qtag_prefix *)skb->data;

-       if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
+       struct qinqtag_prefix {
+               __be16 eth_type; /* ETH_P_8021Q  or ETH_P_8021AD */
+               __be16 tci;
+               __be16 inner_tpid; /* ETH_P_8021Q */
+               __be16 ctci;
+       };
+
+       if (likely(skb_vlan_tag_present(skb))) {
+               key->eth.tci = htons(skb->vlan_tci);
+
+               /* Case where upstream
+                * processing has already stripped the outer vlan tag.
+                */
+               if (unlikely(skb->vlan_proto == htons(ETH_P_8021AD))) {
+                       if (unlikely(skb->len < sizeof(struct qtag_prefix) +
+                                       sizeof(__be16))) {
+                               key->eth.tci = 0;
+                               return 0;
+                       }
+
+                       if (unlikely(!pskb_may_pull(skb,
+                                                   sizeof(struct qtag_prefix) +
+                                                   sizeof(__be16)))) {
+                               return -ENOMEM;
+                       }
+
+                       if (likely(qp->eth_type == htons(ETH_P_8021Q))) {
+                               key->eth.cvlan.ctci =
+                                       qp->tci | htons(VLAN_TAG_PRESENT);
+                               key->eth.cvlan.c_tpid =
+ skb->vlan_proto;

We should directly copy qp->inner_tpid here. As you have done it for
non offloaded case below.
Thanks! It is copied but it is set to the wrong tpid. The c_tpid field in the 
key should be set to the ethertype in the packet itself which is the inner 
tpid, not the offloaded skb-vlan_proto which is the outer tpid. Fixed in V12.

+                               __skb_pull(skb, sizeof(struct qtag_prefix));
+                       }
+               }
                  return 0;
+       }

-       if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
-                                        sizeof(__be16))))
-               return -ENOMEM;

-       qp = (struct qtag_prefix *) skb->data;
-       key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
-       __skb_pull(skb, sizeof(struct qtag_prefix));
+       if (qp->eth_type == htons(ETH_P_8021AD)) {
+               struct qinqtag_prefix *qinqp =
+                                       (struct qinqtag_prefix
+ *)skb->data;
+
+               if (unlikely(skb->len < sizeof(struct qinqtag_prefix) +
+                                       sizeof(__be16)))
+                       return 0;
+
+               if (unlikely(!pskb_may_pull(skb, sizeof(struct qinqtag_prefix) +
+                               sizeof(__be16)))) {
+                       return -ENOMEM;
+               }
+               key->eth.tci = qinqp->tci | htons(VLAN_TAG_PRESENT);
+               key->eth.cvlan.ctci = qinqp->ctci | htons(VLAN_TAG_PRESENT);
+               key->eth.cvlan.c_tpid = qinqp->inner_tpid;
+
+               __skb_pull(skb, sizeof(struct qinqtag_prefix));
+
+               return 0;
+       }
+       if (qp->eth_type == htons(ETH_P_8021Q)) {
+               if (unlikely(skb->len < sizeof(struct qtag_prefix) +
+                                       sizeof(__be16)))
+                       return -ENOMEM;
+
+               if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
+                               sizeof(__be16))))
+                       return 0;
+               key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
+
+               __skb_pull(skb, sizeof(struct qtag_prefix));
+       }

          return 0;
   }
@@ -474,9 +533,10 @@ static int key_extract(struct sk_buff *skb, struct 
sw_flow_key *key)
           */

          key->eth.tci = 0;
-       if (skb_vlan_tag_present(skb))
-               key->eth.tci = htons(skb->vlan_tci);
-       else if (eth->h_proto == htons(ETH_P_8021Q))
+       key->eth.cvlan.ctci = 0;
cvlan.c_tpid is not initialized for all cases.
Fixed in V12

+       if ((skb_vlan_tag_present(skb)) ||
+           (eth->h_proto == htons(ETH_P_8021Q)) ||
+           (eth->h_proto == htons(ETH_P_8021AD)))
These are redundant check. so we can directly call this function.
I don't agree that these 3 checks are redundant. parse_vlan parses both the 
offloaded and non-offloaded cases. In V12, I changed it to call
eth_type_vlan() to do the checks for the non-offloaded ethertypes.

Hmmm ... maybe I should add another function to if_vlan.h to check if a packet 
is a vlan regardless of whether it is offloaded or not?

                  if (unlikely(parse_vlan(skb, key)))
                          return -ENOMEM;


...

+static int cust_vlan_from_nlattrs(struct sw_flow_match *match, u64 attrs,
+                                 const struct nlattr **a, bool is_mask,
+                                 bool log) {
+       /* This should be nested inner or "customer" tci" */
+       if (attrs & (1 << OVS_KEY_ATTR_VLAN)) {
+               __be16 ctci;
+
+               ctci = nla_get_be16(a[OVS_KEY_ATTR_VLAN]);
+               if (!(ctci & htons(VLAN_TAG_PRESENT))) {
+                       if (is_mask)
+                               OVS_NLERR(log, "VLAN CTCI mask does not have exact 
match for VLAN_TAG_PRESENT bit.");
+                       else
+                               OVS_NLERR(log, "VLAN CTCI does not
+ have VLAN_TAG_PRESENT bit set.");
+
+                       return -EINVAL;
+               }
+               SW_FLOW_KEY_PUT(match, eth.cvlan.c_tpid, ctci, is_mask);
+               SW_FLOW_KEY_PUT(match, eth.cvlan.ctci, ctci, is_mask);
+       }
Same value is set to tpid and tci.
Thanks! Fixed in V12.

+       return 0;
+}
+
   static int ovs_key_from_nlattrs(struct sw_flow_match *match, u64 attrs,
                                  const struct nlattr **a, bool is_mask,
                                  bool log) @@ -1024,6 +1047,105 @@
static void mask_set_nlattr(struct nlattr *attr, u8 val)
          nlattr_set(attr, val, ovs_key_lens);
   }

+static int parse_vlan_from_nlattrs(const struct nlattr *nla,
+                                  struct sw_flow_match *match,
+                                  u64 *key_attrs, bool *ie_valid,
+                                  const struct nlattr **a, bool is_mask,
+                                  bool log) {
+       int err;
+       __be16 tci;
+       const struct nlattr *encap;
+
+       if (!is_mask) {
+               u64 v_attrs = 0;
+
+               tci = nla_get_be16(a[OVS_KEY_ATTR_VLAN]);
+
+               if (tci & htons(VLAN_TAG_PRESENT)) {
+                       if (unlikely((nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]) ==
+                                     htons(ETH_P_8021AD)))) {
Since we have added tpid to flow key, we have flexibility of
supporting generic double encapsulation. Therefore in netlink parsing
of key, double encap should not be limited to just 8021AD. for example
it should allow 8021Q in 8021Q header as valid key.
I agree. Although Open Flow specification doesn't support non 802.1AD double tagged 
vlans, we probably should be as least restrictive as possible here in the kernel module. 
I recoded this in V12 to allow a more "generic" qinq.

+                               err = parse_flow_nlattrs(nla, a, &v_attrs, log);
+                               if (err)
+                                       return err;
+                               if (!v_attrs)
+                                       return -EINVAL;
+

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