conntrack: Fix flush not flushing all elements.

On netdev datapath, when a ct element was cleaned, the cmap
could be shrinked, potentially causing some elements to be skipped
in the flush iteration.

Fixes: 967bb5c ("conntrack: Add rcu support.")
Signed-off-by: Xavier Simonart <xsimonar@redhat.com>
Acked-by: Mike Pattrick <mkp@redhat.com>
Signed-off-by: Simon Horman <horms@ovn.org>

Author: simonartxavier

lib/conntrack.c

@@ -2632,25 +2632,19 @@ conntrack_dump_start(struct conntrack *ct, struct conntrack_dump *dump,
 
     dump->ct = ct;
     *ptot_bkts = 1; /* Need to clean up the callers. */
+    dump->cursor = cmap_cursor_start(&ct->conns);
     return 0;
 }
 
 int
 conntrack_dump_next(struct conntrack_dump *dump, struct ct_dpif_entry *entry)
 {
-    struct conntrack *ct = dump->ct;
     long long now = time_msec();
 
-    for (;;) {
-        struct cmap_node *cm_node = cmap_next_position(&ct->conns,
-                                                       &dump->cm_pos);
-        if (!cm_node) {
-            break;
-        }
-        struct conn_key_node *keyn;
-        struct conn *conn;
+    struct conn_key_node *keyn;
+    struct conn *conn;
 
-        INIT_CONTAINER(keyn, cm_node, cm_node);
+    CMAP_CURSOR_FOR_EACH_CONTINUE (keyn, cm_node, &dump->cursor) {
         if (keyn->dir != CT_DIR_FWD) {
             continue;
         }

lib/conntrack.h

@@ -101,8 +101,8 @@ struct conntrack_dump {
     struct conntrack *ct;
     unsigned bucket;
     union {
-        struct cmap_position cm_pos;
         struct hmap_position hmap_pos;
+        struct cmap_cursor cursor;
     };
     bool filter_zone;
     uint16_t zone;

tests/system-traffic.at

@@ -7913,6 +7913,65 @@ AT_CHECK([ovs-pcap client.pcap | grep 000000002010000000002000], [0], [dnl
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([conntrack - Flush many conntrack entries by port])
+CHECK_CONNTRACK()
+OVS_TRAFFIC_VSWITCHD_START()
+
+ADD_NAMESPACES(at_ns0, at_ns1)
+
+ADD_VETH(p0, at_ns0, br0, "10.1.1.1/24")
+ADD_VETH(p1, at_ns1, br0, "10.1.1.2/24")
+
+AT_DATA([flows.txt], [dnl
+priority=100,in_port=1,udp,action=ct(zone=1,commit),2
+])
+
+AT_CHECK([ovs-ofctl --bundle add-flows br0 flows.txt])
+
+dnl 20 packets from port 1 and 1 packet from port 2.
+flow_l3="\
+    eth_src=50:54:00:00:00:09,eth_dst=50:54:00:00:00:0a,dl_type=0x0800,\
+    nw_src=10.1.1.1,nw_dst=10.1.1.2,nw_proto=17,nw_ttl=64,nw_frag=no"
+
+head="50540000000a50540000000908004500005c000000004011648d0a0101010a010102"
+len=72
+base_csum=1366
+tail="000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f\
+      202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f"
+
+dst_port=1
+for src_port in $(seq 1 20); do
+    csum=$((base_csum - src_port - dst_port))
+    frame=$(printf "%s%04x%04x%04x%04x%s" $head 1 $src_port $len $csum $tail)
+    AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 "in_port=1 packet=$frame actions=resubmit(,0)"])
+done
+
+src_port=2
+dst_port=1
+csum=$((base_csum - src_port - dst_port))
+frame=$(printf "%s%04x%04x%04x%04x%s" $head $src_port $dst_port $len $csum $tail)
+AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 "in_port=1 packet=$frame actions=resubmit(,0)"])
+
+: > conntrack
+
+for i in $(seq 1 20); do
+    echo "udp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=1,dport=${i}),reply=(src=10.1.1.2,dst=10.1.1.1,sport=${i},dport=1),zone=1" >> conntrack
+done
+echo "udp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=2,dport=1),reply=(src=10.1.1.2,dst=10.1.1.1,sport=1,dport=2),zone=1" >> conntrack
+
+sort conntrack > expout
+
+AT_CHECK([ovs-appctl dpctl/dump-conntrack zone=1 | grep -F "src=10.1.1.1," | sort ], [0], [expout])
+
+dnl Check that flushing conntrack by port 1 flush all ct for port 1 but keeps ct for port 2.
+AT_CHECK([ovs-appctl dpctl/flush-conntrack zone=1 'ct_nw_proto=17,ct_tp_src=1'])
+AT_CHECK([ovs-appctl dpctl/dump-conntrack zone=1 | grep -F "src=10.1.1.1," | sort ], [0], [dnl
+udp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=2,dport=1),reply=(src=10.1.1.2,dst=10.1.1.1,sport=1,dport=2),zone=1
+])
+
+OVS_TRAFFIC_VSWITCHD_STOP
+AT_CLEANUP
+
 AT_BANNER([IGMP])
 
 AT_SETUP([IGMP - flood under normal action])