ovn-trace: Set ct_state if not already set when tracing ct(nat).

Since 0038579 ("northd: Optimize ct nat for load balancer
traffic.") calls to 'ct()' and 'ct(nat)' are merged because 'ct(nat)'
implies 'ct()'.  However ovn-trace was not setting ct_state when
processing 'ct(nat)'.  This was yielding unexpected results.

Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=2017540
Reported-by: Surya Seetharaman <surya@redhat.com>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: Numan Siddique <numans@ovn.org>
(cherry picked from commit c117ce1)

tests/ovn-northd.at

@@ -3732,3 +3732,42 @@ wait_row_count Datapath_Binding 1
 
 AT_CLEANUP
 ])
+
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([conntrack nat implies conntrack])
+ovn_start
+
+check ovn-nbctl lr-add rtr \
+  -- set logical_router rtr options:chassis=hv \
+  -- lrp-add rtr rtr-ls 00:00:00:00:01:00 42.42.42.1/24 \
+  -- lb-add lb-test 43.43.43.43:4343 42.42.42.2:4242 tcp \
+  -- lr-lb-add rtr lb-test
+check ovn-nbctl --wait=sb sync
+
+flow="eth.dst == 00:00:00:00:01:00 && inport == \"rtr-ls\" && ip4.src == 42.42.42.42 && ip4.dst == 43.43.43.43 && ip.ttl == 64 && tcp && tcp.dst == 4343"
+
+AT_CHECK_UNQUOTED([ovn-trace --ct new --minimal "${flow}" --lb-dst 42.42.42.42:4242], [0], [dnl
+# tcp,reg14=0x1,vlan_tci=0x0000,dl_src=00:00:00:00:00:00,dl_dst=00:00:00:00:01:00,nw_src=42.42.42.42,nw_dst=43.43.43.43,nw_tos=0,nw_ecn=0,nw_ttl=64,tp_src=0,tp_dst=4343,tcp_flags=0
+ct_dnat /* assuming no un-dnat entry, so no change */ {
+    ct_lb {
+        ip.ttl--;
+        eth.src = 00:00:00:00:01:00;
+        eth.dst = 00:00:00:00:00:00;
+        arp {
+            eth.dst = ff:ff:ff:ff:ff:ff;
+            arp.spa = 0x2a2a2a01;
+            arp.tpa = 0x2a2a2a02;
+            arp.op = 1;
+            output("rtr-ls");
+        };
+    };
+};
+])
+
+AT_CHECK_UNQUOTED([ovn-trace --minimal "${flow}" --lb-dst 42.42.42.42:4242], [0], [dnl
+# tcp,reg14=0x1,vlan_tci=0x0000,dl_src=00:00:00:00:00:00,dl_dst=00:00:00:00:01:00,nw_src=42.42.42.42,nw_dst=43.43.43.43,nw_tos=0,nw_ecn=0,nw_ttl=64,tp_src=0,tp_dst=4343,tcp_flags=0
+ct_dnat /* assuming no un-dnat entry, so no change */ /* default (use --ct to customize) */;
+])
+
+AT_CLEANUP
+])

utilities/ovn-trace.c

@@ -199,6 +199,17 @@ parse_ct_option(const char *state_s_)
     ct_states[n_ct_states++] = state;
 }
 
+static uint32_t
+next_ct_state(struct ds *out_comment)
+{
+    if (ct_state_idx < n_ct_states) {
+        return ct_states[ct_state_idx++];
+    } else {
+        ds_put_format(out_comment, " /* default (use --ct to customize) */");
+        return CS_ESTABLISHED | CS_TRACKED;
+    }
+}
+
 static void
 parse_lb_option(const char *s)
 {
@@ -2248,23 +2259,17 @@ execute_ct_next(const struct ovnact_ct_next *ct_next,
                 enum ovnact_pipeline pipeline, struct ovs_list *super)
 {
     /* Figure out ct_state. */
-    uint32_t state;
-    const char *comment;
-    if (ct_state_idx < n_ct_states) {
-        state = ct_states[ct_state_idx++];
-        comment = "";
-    } else {
-        state = CS_ESTABLISHED | CS_TRACKED;
-        comment = " /* default (use --ct to customize) */";
-    }
+    struct ds comment = DS_EMPTY_INITIALIZER;
+    uint32_t state = next_ct_state(&comment);
 
     /* Make a sub-node for attaching the next table. */
     struct ds s = DS_EMPTY_INITIALIZER;
     format_flags(&s, ct_state_to_string, state, '|');
     struct ovntrace_node *node = ovntrace_node_append(
         super, OVNTRACE_NODE_TRANSFORMATION, "ct_next(ct_state=%s%s)",
-        ds_cstr(&s), comment);
+        ds_cstr(&s), ds_cstr(&comment));
     ds_destroy(&s);
+    ds_destroy(&comment);
 
     /* Trace the actions in the next table. */
     struct flow ct_flow = *uflow;
@@ -2309,6 +2314,12 @@ execute_ct_nat(const struct ovnact_ct_nat *ct_nat,
         ds_put_format(&s, " /* assuming no un-%cnat entry, so no change */",
                       direction[0]);
     }
+
+    /* ct(nat) implies ct(). */
+    if (!(ct_flow.ct_state & CS_TRACKED)) {
+        ct_flow.ct_state |= next_ct_state(&s);
+    }
+
     struct ovntrace_node *node = ovntrace_node_append(
         super, OVNTRACE_NODE_TRANSFORMATION, "%s", ds_cstr(&s));
     ds_destroy(&s);