[ovs-dev] [PATCH ovn] northd: Support flow offloading for logical switches with no ACLs.
Numan Siddique
numans at ovn.org
Fri May 7 14:35:52 UTC 2021
On Fri, May 7, 2021 at 5:50 AM Dumitru Ceara <dceara at redhat.com> wrote:
>
> On 5/6/21 3:52 PM, numans at ovn.org wrote:
> > From: Numan Siddique <numans at ovn.org>
> >
> > Some smart NICs can't offload datapath flows matching on conntrack
> > fields. If a deployment desires to make use of such smart NICs
> > then it cannot configure ACLs on the logical switches. If suppose
> > a logical switch S1 has no ACLs configured and a logical switch S2
> > has ACLs configured, then the CMS would expect the datapath flows
> > belonging to S1 logical ports are offloaded since it has no ACLs.
> > But this is not working as expected (even if S1 and S2 are
> > not connected via a logical router).
> >
> > ovn-northd generates the below logical flows in ls_in_acl_hint
> > and ls_in_acl stages for S1
> >
> > table=8 (ls_in_acl_hint ), priority=0 , match=(1), action=(next;)
> > table=9 (ls_in_acl ), priority=0 , match=(1), action=(next;)
> >
> > And the below for S2
> >
> > table=8 (ls_in_acl_hint ), priority=7 , match=(ct.new && !ct.est), action=(reg0[7] = 1; reg0[9] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=6 , match=(!ct.new && ct.est && !ct.rpl && ct_label.blocked == 1), action=(reg0[7] = 1; reg0[9] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=5 , match=(!ct.trk), action=(reg0[8] = 1; reg0[9] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=4 , match=(!ct.new && ct.est && !ct.rpl && ct_label.blocked == 0), action=(reg0[8] = 1; reg0[10] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=3 , match=(!ct.est), action=(reg0[9] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=2 , match=(ct.est && ct_label.blocked == 1), action=(reg0[9] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=1 , match=(ct.est && ct_label.blocked == 0), action=(reg0[10] = 1; next;)
> > table=8 (ls_in_acl_hint ), priority=0 , match=(1), action=(next;)
> > table=9 (ls_in_acl ), priority=65535, match=(!ct.est && ct.rel && !ct.new && !ct.inv && ct_label.blocked == 0), action=(next;)
> > table=9 (ls_in_acl ), priority=65535, match=(ct.est && !ct.rel && !ct.new && !ct.inv && ct.rpl && ct_label.blocked == 0), action=(next;)
> > table=9 (ls_in_acl ), priority=65535, match=(ct.inv || (ct.est && ct.rpl && ct_label.blocked == 1)), action=(drop;)
> > table=9 (ls_in_acl ), priority=65535, match=(nd || nd_ra || nd_rs || mldv1 || mldv2), action=(next;)
> > table=9 (ls_in_acl ), priority=34000, match=(eth.dst == $svc_monitor_mac), action=(next;)
> > table=9 (ls_in_acl ), priority=1 , match=(ip && (!ct.est || (ct.est && ct_label.blocked == 1))), action=(reg0[1] = 1; next;)
> > table=9 (ls_in_acl ), priority=0 , match=(1), action=(next;)
> >
> > Because there are higher priority flows in 'ls_in_acl_hint' and
> > 'ls_in_acl' with the match on conntrack fields,
> > ovs-vswitchd will generate a datapath flow with the match on ct_state fields as -
> > 'ct_state(-new-est-rel-rpl-inv-trk)' for the packet from S1, even though
> > the S1 pipeline doesn't have logical flows which match on conntrack
> > fields. [1] has more information.
> >
> > Modifying the below flows if a logical switch has no ACLs solves this
> > problem.
> >
> > table=8 (ls_in_acl_hint ), priority=65535 , match=(1), action=(next;)
> > table=9 (ls_in_acl ), priority=65535 , match=(1), action=(next;)
> >
> > With the above flows with higher priority, ovs-vswitchd will not
> > consider other flows in the same table during translation.
> >
> > This patch addresses this issue by using higher prioriy flows (for both
> > ls_in_acl* and ls_out_acl* stages).
> >
> > [1] - https://bugzilla.redhat.com/show_bug.cgi?id=1955191#c8
> >
> > Signed-off-by: Numan Siddique <numans at ovn.org>
> > ---
>
> Hi Numan,
>
> This needs a rebase after the recent commits to master.
Thanks for the review. Sure I'll rebase and submit v2.
>
> > northd/lswitch.dl | 12 ++++
> > northd/ovn-northd.8.xml | 32 ++++++----
> > northd/ovn-northd.c | 62 ++++++++++++++-----
> > northd/ovn_northd.dl | 62 +++++++++++--------
> > tests/ovn-northd.at | 51 ++++++++++++----
> > tests/system-ovn.at | 130 ++++++++++++++++++++++++++++++++++++++++
> > 6 files changed, 284 insertions(+), 65 deletions(-)
> >
> > diff --git a/northd/lswitch.dl b/northd/lswitch.dl
> > index 47c497e0cf..9bcfe9c321 100644
> > --- a/northd/lswitch.dl
> > +++ b/northd/lswitch.dl
> > @@ -125,6 +125,15 @@ LogicalSwitchHasStatefulACL(ls, false) :-
> > nb::Logical_Switch(._uuid = ls),
> > not LogicalSwitchStatefulACL(ls, _).
> >
> > +relation LogicalSwitchHasACLs(ls: uuid, has_acls: bool)
> > +
> > +LogicalSwitchHasACLs(ls, true) :-
> > + LogicalSwitchACL(ls, _).
> > +
> > +LogicalSwitchHasACLs(ls, false) :-
> > + nb::Logical_Switch(._uuid = ls),
> > + not LogicalSwitchACL(ls, _).
> > +
> > /*
> > * LogicalSwitchLocalnetPorts maps from each logical switch UUID
> > * to the logical switch's set of localnet ports. Each localnet
> > @@ -189,6 +198,7 @@ LogicalSwitchHasNonRouterPort(ls, false) :-
> > relation &Switch(
> > ls: nb::Logical_Switch,
> > has_stateful_acl: bool,
> > + has_acls: bool,
> > has_lb_vip: bool,
> > has_dns_records: bool,
> > has_unknown_ports: bool,
> > @@ -215,6 +225,7 @@ function ipv6_parse_prefix(s: string): Option<in6_addr> {
> >
> > &Switch(.ls = ls,
> > .has_stateful_acl = has_stateful_acl,
> > + .has_acls = has_acls,
> > .has_lb_vip = has_lb_vip,
> > .has_dns_records = has_dns_records,
> > .has_unknown_ports = has_unknown_ports,
> > @@ -226,6 +237,7 @@ function ipv6_parse_prefix(s: string): Option<in6_addr> {
> > .is_vlan_transparent = is_vlan_transparent) :-
> > nb::Logical_Switch[ls],
> > LogicalSwitchHasStatefulACL(ls._uuid, has_stateful_acl),
> > + LogicalSwitchHasACLs(ls._uuid, has_acls),
> > LogicalSwitchHasLBVIP(ls._uuid, has_lb_vip),
> > LogicalSwitchHasDNSRecords(ls._uuid, has_dns_records),
> > LogicalSwitchHasUnknownPorts(ls._uuid, has_unknown_ports),
> > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> > index 54e88d3fac..90a1f7d0b3 100644
> > --- a/northd/ovn-northd.8.xml
> > +++ b/northd/ovn-northd.8.xml
> > @@ -545,6 +545,14 @@
> > <p>
> > The table contains the following flows:
> > </p>
> > + <ul>
> > + <li>
> > + A priority-65535 flow to advance to the next table if the logical
> > + switch has <code>no</code> ACLs configured, otherwise a
> > + priority-0 flow to advance to the next table.
> > + </li>
> > + </ul>
> > +
> > <ul>
> > <li>
> > A priority-7 flow that matches on packets that initiate a new session.
> > @@ -585,9 +593,6 @@
> > This flow sets <code>reg0[10]</code> and then advances to the next
> > table.
> > </li>
> > - <li>
> > - A priority-0 flow to advance to the next table.
> > - </li>
> > </ul>
> >
> > <h3>Ingress table 9: <code>from-lport</code> ACLs</h3>
> > @@ -633,9 +638,14 @@
> > </ul>
> >
> > <p>
> > - This table also contains a priority 0 flow with action
> > - <code>next;</code>, so that ACLs allow packets by default. If the
> > - logical datapath has a stateful ACL or a load balancer with VIP
> > + This table contains a priority-65535 flow to advance to the next table
> > + if the logical switch has <code>no</code> ACLs configured, otherwise a
> > + priority-0 flow to advance to the next table so that ACLs allow
> > + packets by default.
> > + </p>
> > +
> > + <p>
> > + If the logical datapath has a stateful ACL or a load balancer with VIP
> > configured, the following flows will also be added:
> > </p>
> >
> > @@ -649,7 +659,7 @@
> > </li>
> >
> > <li>
> > - A priority-65535 flow that allows any traffic in the reply
> > + A priority-65532 flow that allows any traffic in the reply
> > direction for a connection that has been committed to the
> > connection tracker (i.e., established flows), as long as
> > the committed flow does not have <code>ct_label.blocked</code> set.
> > @@ -662,19 +672,19 @@
> > </li>
> >
> > <li>
> > - A priority-65535 flow that allows any traffic that is considered
> > + A priority-65532 flow that allows any traffic that is considered
> > related to a committed flow in the connection tracker (e.g., an
> > ICMP Port Unreachable from a non-listening UDP port), as long
> > as the committed flow does not have <code>ct_label.blocked</code> set.
> > </li>
> >
> > <li>
> > - A priority-65535 flow that drops all traffic marked by the
> > + A priority-65532 flow that drops all traffic marked by the
> > connection tracker as invalid.
> > </li>
> >
> > <li>
> > - A priority-65535 flow that drops all traffic in the reply direction
> > + A priority-65532 flow that drops all traffic in the reply direction
> > with <code>ct_label.blocked</code> set meaning that the connection
> > should no longer be allowed due to a policy change. Packets
> > in the request direction are skipped here to let a newly created
> > @@ -682,7 +692,7 @@
> > </li>
> >
> > <li>
> > - A priority-65535 flow that allows IPv6 Neighbor solicitation,
> > + A priority-65532 flow that allows IPv6 Neighbor solicitation,
> > Neighbor discover, Router solicitation, Router advertisement and MLD
> > packets.
> > </li>
> > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> > index 94fae5648a..dfe4225bb3 100644
> > --- a/northd/ovn-northd.c
> > +++ b/northd/ovn-northd.c
> > @@ -627,6 +627,7 @@ struct ovn_datapath {
> > bool has_stateful_acl;
> > bool has_lb_vip;
> > bool has_unknown;
> > + bool has_acls;
> >
> > /* IPAM data. */
> > struct ipam_info ipam_info;
> > @@ -4783,6 +4784,23 @@ ls_has_stateful_acl(struct ovn_datapath *od)
> > return false;
> > }
> >
> > +static bool
> > +ls_has_acls(struct ovn_datapath *od)
> > +{
> > + if (od->nbs->n_acls) {
> > + return true;
> > + }
> > +
> > + struct ovn_ls_port_group *ls_pg;
> > + HMAP_FOR_EACH (ls_pg, key_node, &od->nb_pgs) {
> > + if (ls_pg->nb_pg->n_acls) {
> > + return true;
> > + }
> > + }
> > +
> > + return false;
> > +}
>
> nit: ls_has_stateful_acl() and ls_has_acl() both walk the port groups
> associated to a logical switch. I wonder if it makes sense to combine
> the functions in one that sets both "has_acls" and "has_stateful_acl" in
> one go.
>
Ack. Sounds good.
> > +
> > /* Logical switch ingress table 0: Ingress port security - L2
> > * (priority 50).
> > * Ingress table 1: Ingress port security - IP (priority 90 and 80)
> > @@ -5237,7 +5255,11 @@ build_acl_hints(struct ovn_datapath *od, struct hmap *lflows)
> > enum ovn_stage stage = stages[i];
> >
> > /* In any case, advance to the next stage. */
> > - ovn_lflow_add(lflows, od, stage, 0, "1", "next;");
> > + if (!od->has_acls && !od->has_lb_vip) {
> > + ovn_lflow_add(lflows, od, stage, UINT16_MAX, "1", "next;");
> > + } else {
> > + ovn_lflow_add(lflows, od, stage, 0, "1", "next;");
> > + }
> >
> > if (!od->has_stateful_acl && !od->has_lb_vip) {
> > continue;
>
> I didn't test this it out thoroughly but isn't it enough to change this
> whole block to:
>
> if (!od->has_stateful_acl && !od->has_lb_vip) {
> ovn_lflow_add(lflows, od, stage, UINT16_MAX, "1", "next;");
> continue;
> } else {
> ovn_lflow_add(lflows, od, stage, 0, "1", "next;");
> }
Not really.
If a logical switch has no ACLs or no LB VIPs we want to add
65535-prio flow to advance the
packet to the next stage. But if a logical switch has any ACL (be it
allow, allow-related or drop)
we want to add a normal 0-priority flow to advance the packet to the next stage.
Thanks
Numan
>
> Regards,
> Dumitru
>
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