On Wed, Jan 16, 2013 at 05:38:08PM +0900, Simon Horman wrote:
> On Tue, Jan 15, 2013 at 11:05:45PM -0800, Ben Pfaff wrote:
> > On Tue, Jan 08, 2013 at 02:46:02PM +0900, Simon Horman wrote:
> > > diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
> > > index 5e32965..b421753 100644
> > > --- a/include/linux/openvswitch.h
> > > +++ b/include/linux/openvswitch.h
> > > @@ -282,6 +282,7 @@ enum ovs_key_attr {
> > > OVS_KEY_ATTR_ARP, /* struct ovs_key_arp */
> > > OVS_KEY_ATTR_ND, /* struct ovs_key_nd */
> > > OVS_KEY_ATTR_SKB_MARK, /* u32 skb mark */
> > > + OVS_KEY_ATTR_MPLS, /* struct ovs_key_mpls */
> > > OVS_KEY_ATTR_IPV4_TUNNEL, /* struct ovs_key_ipv4_tunnel */
> > > OVS_KEY_ATTR_TUN_ID = 63, /* be64 tunnel ID */
> > > __OVS_KEY_ATTR_MAX
> >
> > I'm pretty sure we shouldn't be inserting OVS_KEY_ATTR_MPLS in front of
> > another value that we're already aiming to get upstream. I'd suggest a
> > value of 62.
> >
> > Jesse, does that sound reasonable to you? Another alternative would be
> > to avoid modifying <linux/openvswitch.h> entirely, one way or another,
> > until we have real kernel support, which would be a little extra work.
>
> I'll use 62 unless I hear otherwise from Jesse.
>
> > I'm not sure why we have OVS_ACTION_ATTR_SET_MPLS instead of using
> > OVS_ACTION_SET to set OVS_KEY_ATTR_MPLS.
>
> I'll switch over to using OVS_ACTION_SET+OVS_KEY_ATTR_MPLS,
> it seems to be in keeping with the existing code.
>
> >
> > > +/* Action structure for NXAST_PUSH_VLAN/MPLS. */
> > > +struct nx_action_push {
> > > + ovs_be16 type; /* OFPAT_PUSH_VLAN/MPLS. */
> >
> > The above two comments are wrong, there's no NXAST_PUSH_VLAN. And the
> > struct should be named nx_action_push_mpls, not more generically. (This
> > must be a leftover from Ravi's initial patch that also added QinQ.)
> >
> > > + ovs_be16 len; /* Length is 8. */
> > > + ovs_be32 vendor; /* NX_VENDOR_ID. */
> > > + ovs_be16 subtype; /* NXAST_PUSH_MPLS. */
> > > + ovs_be16 ethertype; /* Ethertype */
> > > + uint8_t pad[4];
> > > +};
> > > +OFP_ASSERT(sizeof(struct nx_action_push) == 16);
> >
> > > @@ -1271,6 +1272,20 @@ dp_netdev_execute_actions(struct dp_netdev *dp,
> > > eth_pop_vlan(packet);
> > > break;
> > >
> > > + case OVS_ACTION_ATTR_PUSH_MPLS: {
> > > + const struct ovs_action_push_mpls *mpls = nl_attr_get(a);
> > > + push_mpls(packet, mpls->mpls_ethertype, mpls->mpls_label);
> > > + break;
> >
> > The similar OVS_ACTION_ATTR_PUSH_VLAN case declares its variable at the
> > outer block. Please make the code consistent one way or another on this
> > score.
I will supply a patch to localise the vlan variable for
OVS_ACTION_ATTR_PUSH_VLAN as this approach reduces clutter at the top
of the loop and keeps variables close to where they are used.
> > The breakdown of code between parse_mpls() and parse_remaining_mpls()
> > seems odd. I'd just write one function.
> >
> > In mf_is_value_valid(), I think that the MFF_MPLS_TC and MFF_MPLS_BOS
> > cases should check the u8 member, not be32. Same for
> > mf_random_value(). Also htonl won't be needed for u8.
> >
> > Most of the meta-flow functions present the cases in the order label,
> > tc, bos, but mf_set_value() uses a different order. Can you make it
> > consistent?
> >
> > In enum mf_prereqs, it might be best to add an "L2.5" category for MPLS.
> >
> > This adds a double blank line in nx_put_raw(). (Oh the horror!)
> >
> > Also in nx_put_raw(), missing space after the comma here:
> > + nxm_put_8(b,OXM_OF_MPLS_TC, mpls_lse_to_tc(flow->mpls_lse));
> >
> > parse_l3_onward() has a ";;":
> > + ovs_be16 dl_type = flow->dl_type;;
> >
> > parse_l3_onward() could use flow_innermost_dl_type() since that's what
> > it's effectively calculating as 'dl_type' (maybe it should be
> > 'inner_dl_type' or 'innermost_dl_type').
I'm not so sure about this.
flow_innermost_dl_type(), in its current incantation, is used to
obtain the innermost dl_type of a struct flow. In other words,
it reads flow->encap_dl_type.
On the other hand, parse_l3_onward() may write flow->encap_dl_type
and never reads it.
> > Is there any sense in handling cases in commit_mpls_action() where the
> > mpls_depth has to change by more than 1? Should we log an error at
> > least?
I think that logging is a good approach.
I have update the code as follows:
if (flow->mpls_depth < base->mpls_depth) {
if (base->mpls_depth - flow->mpls_depth > 1) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 10);
VLOG_WARN_RL(&rl, "Multiple mpls_pop actions reduced to "
" a single mpls_pop action");
}
nl_msg_put_be16(odp_actions, OVS_ACTION_ATTR_POP_MPLS, flow->dl_type);
} else if (flow->mpls_depth > base->mpls_depth) {
struct ovs_action_push_mpls *mpls;
if (flow->mpls_depth - base->mpls_depth > 1) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 10);
VLOG_WARN_RL(&rl, "Multiple mpls_push actions reduced to "
" a single mpls_push action");
}
...
> > The comment on struct ofpact_push is getting ahead of ourselves, since
> > we have an OFPACT_PUSH_VLAN but it doesn't use this structure and no one
> > has even mentioned PBB for OVS yet, at least not to me:
> >
> > +/* OFPACT_PUSH_VLAN/MPLS/PBB
> > + *
> > + * used for NXAST_PUSH_MPLS, OFPAT13_PUSH_VLAN/MPLS/PBB */
> > +struct ofpact_push {
> > + struct ofpact ofpact;
> > + ovs_be16 ethertype;
> > +};
Thanks. I'm not even sure that I know what PBB is.
I will also rename ofpact_push as ofpact_push_mpls.
> >
> > You can remove the bit about "negotiation of an OF1.3 session is not yet
> > supported" from this comment in ofputil_usable_protocols():
> > + /* NXM and OF1.3+ support matching MPLS label */
> > + /* Allow for OF1.2 as there doesn't seem to be a
> > + * particularly good reason not to and negotiation
> > + * of an OF1.3 session is not yet supported. */
> >
> > In ofputil_normalize_match__() should we also mask off mpls_depth if
> > !MAY_MPLS? I guess so.
Yes, I think so.
> > It's getting late here so I'll resume looking at this patch starting at
> > lib/packets.c next chance I get.
>
> All the above seems reasonable. I've started working on making it so.
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