From 2baa1b74fb8e93e158d4800d9e42e24b70b3970a Mon Sep 17 00:00:00 2001
From: Dumitru Ceara <dceara@redhat.com>
Date: Wed, 24 Feb 2021 17:10:07 +0100
Subject: [PATCH 16/16] northd: Avoid matching on ct.dnat flags for load
balancers.
Matching on ct.dnat creates openflows that often are not offloadable
to hardware. ovn-northd uses ct.dnat only for load balancer hairpin
traffic handling and it turns out we don't really need to match on
ct.dnat.
Acked-by: Numan Siddique <numans@ovn.org>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: Numan Siddique <numans@ovn.org>
(cherry picked from upstream commit 110e670462a9ae580d40d14181c388fc2f0b1e1c)
Change-Id: Icea5badee2d4a83ac33f45557e39ebd47bf6192b
---
northd/ovn-northd.8.xml | 38 +++++++++++++++++++-----------------
northd/ovn-northd.c | 52 ++++++++++++++++++++++++++++++-------------------
tests/ovn-northd.at | 29 +++++++++++++++++++++++++++
3 files changed, 81 insertions(+), 38 deletions(-)
diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
index c2de5ba..0a22023 100644
--- a/northd/ovn-northd.8.xml
+++ b/northd/ovn-northd.8.xml
@@ -812,20 +812,13 @@
<ul>
<li>
If the logical switch has load balancer(s) configured, then a
- priorirty-100 flow is added with the match
- <code>ip && ct.trk&& ct.dnat</code> to check if the
+ priority-100 flow is added with the match
+ <code>ip && ct.trk</code> to check if the
packet needs to be hairpinned (if after load balancing the destination
- IP matches the source IP) or not by executing the action
- <code>reg0[6] = chk_lb_hairpin();</code> and advances the packet to
- the next table.
- </li>
-
- <li>
- If the logical switch has load balancer(s) configured, then a
- priorirty-90 flow is added with the match <code>ip</code> to check if
- the packet is a reply for a hairpinned connection or not by executing
- the action <code>reg0[6] = chk_lb_hairpin_reply();</code> and advances
- the packet to the next table.
+ IP matches the source IP) or not by executing the actions
+ <code>reg0[6] = chk_lb_hairpin();</code> and
+ <code>reg0[12] = chk_lb_hairpin_reply();</code> and advances the packet
+ to the next table.
</li>
<li>
@@ -837,17 +830,26 @@
<ul>
<li>
If the logical switch has load balancer(s) configured, then a
- priorirty-100 flow is added with the match
- <code>ip && (ct.new || ct.est) && ct.trk &&
- ct.dnat && reg0[6] == 1</code> which hairpins the traffic by
+ priority-100 flow is added with the match
+ <code>ip && ct.new && ct.trk &&
+ reg0[6] == 1</code> which hairpins the traffic by
NATting source IP to the load balancer VIP by executing the action
<code>ct_snat_to_vip</code> and advances the packet to the next table.
</li>
<li>
If the logical switch has load balancer(s) configured, then a
- priorirty-90 flow is added with the match
- <code>ip && reg0[6] == 1</code> which matches on the replies
+ priority-100 flow is added with the match
+ <code>ip && ct.est && ct.trk &&
+ reg0[6] == 1</code> which hairpins the traffic by
+ NATting source IP to the load balancer VIP by executing the action
+ <code>ct_snat</code> and advances the packet to the next table.
+ </li>
+
+ <li>
+ If the logical switch has load balancer(s) configured, then a
+ priority-90 flow is added with the match
+ <code>ip && reg0[12] == 1</code> which matches on the replies
of hairpinned traffic (i.e., destination IP is VIP,
source IP is the backend IP and source L4 port is backend port for L4
load balancers) and executes <code>ct_snat</code> and advances the
diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index 9209c13..c1614d8 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -231,6 +231,7 @@ enum ovn_stage {
#define REGBIT_ACL_HINT_DROP "reg0[9]"
#define REGBIT_ACL_HINT_BLOCK "reg0[10]"
#define REGBIT_LKUP_FDB "reg0[11]"
+#define REGBIT_HAIRPIN_REPLY "reg0[12]"
#define REG_ORIG_DIP_IPV4 "reg1"
#define REG_ORIG_DIP_IPV6 "xxreg1"
@@ -270,7 +271,8 @@ enum ovn_stage {
*
* Logical Switch pipeline:
* +----+----------------------------------------------+---+------------------+
- * | R0 | REGBIT_{CONNTRACK/DHCP/DNS/HAIRPIN} | | |
+ * | R0 | REGBIT_{CONNTRACK/DHCP/DNS} | | |
+ * | | REGBIT_{HAIRPIN/HAIRPIN_REPLY} | X | |
* | | REGBIT_ACL_HINT_{ALLOW_NEW/ALLOW/DROP/BLOCK} | X | |
* +----+----------------------------------------------+ X | |
* | R1 | ORIG_DIP_IPV4 (>= IN_STATEFUL) | R | |
@@ -6260,39 +6262,49 @@ build_lb_hairpin(struct ovn_datapath *od, struct hmap *lflows)
ovn_lflow_add(lflows, od, S_SWITCH_IN_HAIRPIN, 0, "1", "next;");
if (od->has_lb_vip) {
- /* Check if the packet needs to be hairpinned. */
- ovn_lflow_add_with_hint(lflows, od, S_SWITCH_IN_PRE_HAIRPIN, 100,
- "ip && ct.trk && ct.dnat",
- REGBIT_HAIRPIN " = chk_lb_hairpin(); next;",
+ /* Check if the packet needs to be hairpinned.
+ * Set REGBIT_HAIRPIN in the original direction and
+ * REGBIT_HAIRPIN_REPLY in the reply direction.
+ */
+ ovn_lflow_add_with_hint(
+ lflows, od, S_SWITCH_IN_PRE_HAIRPIN, 100, "ip && ct.trk",
+ REGBIT_HAIRPIN " = chk_lb_hairpin(); "
+ REGBIT_HAIRPIN_REPLY " = chk_lb_hairpin_reply(); "
+ "next;",
+ &od->nbs->header_);
+
+ /* If packet needs to be hairpinned, snat the src ip with the VIP
+ * for new sessions. */
+ ovn_lflow_add_with_hint(lflows, od, S_SWITCH_IN_NAT_HAIRPIN, 100,
+ "ip && ct.new && ct.trk"
+ " && "REGBIT_HAIRPIN " == 1",
+ "ct_snat_to_vip; next;",
&od->nbs->header_);
- /* Check if the packet is a reply of hairpinned traffic. */
- ovn_lflow_add_with_hint(lflows, od, S_SWITCH_IN_PRE_HAIRPIN, 90, "ip",
- REGBIT_HAIRPIN " = chk_lb_hairpin_reply(); "
- "next;", &od->nbs->header_);
-
- /* If packet needs to be hairpinned, snat the src ip with the VIP. */
+ /* If packet needs to be hairpinned, for established sessions there
+ * should already be an SNAT conntrack entry.
+ */
ovn_lflow_add_with_hint(lflows, od, S_SWITCH_IN_NAT_HAIRPIN, 100,
- "ip && (ct.new || ct.est) && ct.trk && ct.dnat"
+ "ip && ct.est && ct.trk"
" && "REGBIT_HAIRPIN " == 1",
- "ct_snat_to_vip; next;",
+ "ct_snat;",
&od->nbs->header_);
/* For the reply of hairpinned traffic, snat the src ip to the VIP. */
ovn_lflow_add_with_hint(lflows, od, S_SWITCH_IN_NAT_HAIRPIN, 90,
- "ip && "REGBIT_HAIRPIN " == 1", "ct_snat;",
+ "ip && "REGBIT_HAIRPIN_REPLY " == 1",
+ "ct_snat;",
&od->nbs->header_);
/* Ingress Hairpin table.
* - Priority 1: Packets that were SNAT-ed for hairpinning should be
* looped back (i.e., swap ETH addresses and send back on inport).
*/
- ovn_lflow_add(lflows, od, S_SWITCH_IN_HAIRPIN, 1,
- REGBIT_HAIRPIN " == 1",
- "eth.dst <-> eth.src;"
- "outport = inport;"
- "flags.loopback = 1;"
- "output;");
+ ovn_lflow_add(
+ lflows, od, S_SWITCH_IN_HAIRPIN, 1,
+ "("REGBIT_HAIRPIN " == 1 || " REGBIT_HAIRPIN_REPLY " == 1)",
+ "eth.dst <-> eth.src; outport = inport; flags.loopback = 1; "
+ "output;");
}
}
diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
index e252fc0..3592c04 100644
--- a/tests/ovn-northd.at
+++ b/tests/ovn-northd.at
@@ -2185,6 +2185,35 @@ check_column "$lb0_uuid" sb:datapath_binding load_balancers external_ids:name=sw
AT_CLEANUP
+AT_SETUP([ovn -- LS load balancer hairpin logical flows])
+ovn_start
+
+check ovn-nbctl \
+ -- ls-add sw0 \
+ -- lb-add lb0 10.0.0.10:80 10.0.0.4:8080 \
+ -- ls-lb-add sw0 lb0
+
+check ovn-nbctl --wait=sb sync
+
+AT_CHECK([ovn-sbctl lflow-list sw0 | grep ls_in_pre_hairpin | sort], [0], [dnl
+ table=14(ls_in_pre_hairpin ), priority=0 , match=(1), action=(next;)
+ table=14(ls_in_pre_hairpin ), priority=100 , match=(ip && ct.trk), action=(reg0[[6]] = chk_lb_hairpin(); reg0[[12]] = chk_lb_hairpin_reply(); next;)
+])
+
+AT_CHECK([ovn-sbctl lflow-list sw0 | grep ls_in_nat_hairpin | sort], [0], [dnl
+ table=15(ls_in_nat_hairpin ), priority=0 , match=(1), action=(next;)
+ table=15(ls_in_nat_hairpin ), priority=100 , match=(ip && ct.est && ct.trk && reg0[[6]] == 1), action=(ct_snat;)
+ table=15(ls_in_nat_hairpin ), priority=100 , match=(ip && ct.new && ct.trk && reg0[[6]] == 1), action=(ct_snat_to_vip; next;)
+ table=15(ls_in_nat_hairpin ), priority=90 , match=(ip && reg0[[12]] == 1), action=(ct_snat;)
+])
+
+AT_CHECK([ovn-sbctl lflow-list sw0 | grep ls_in_hairpin | sort], [0], [dnl
+ table=16(ls_in_hairpin ), priority=0 , match=(1), action=(next;)
+ table=16(ls_in_hairpin ), priority=1 , match=((reg0[[6]] == 1 || reg0[[12]] == 1)), action=(eth.dst <-> eth.src; outport = inport; flags.loopback = 1; output;)
+])
+
+AT_CLEANUP
+
AT_SETUP([ovn -- logical gatapath groups])
AT_KEYWORDS([use_logical_dp_groups])
ovn_start
--
1.8.3.1