On Mon, Feb 26, 2024 at 5:50 AM Xavier Simonart <xsimo...@redhat.com> wrote:
>
> 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: 967bb5c5cd90 ("conntrack: Add rcu support.")
> Signed-off-by: Xavier Simonart <xsimo...@redhat.com>
Thank you for the patch, I was able to test this out, verify the issue
is as you described, and that your patch fixes the problem.
> ---
> v2: - Updated commit message.
> - Use compose-packet instead of hex packet content.
> - Use dnl for comments.
> - Remove unnecessary errors in OVS_TRAFFIC_VSWITCHD_STOP.
> - Rebased on origin/master.
> ---
> lib/conntrack.c | 14 ++++--------
> lib/conntrack.h | 1 +
> tests/system-traffic.at | 47 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 52 insertions(+), 10 deletions(-)
>
> diff --git a/lib/conntrack.c b/lib/conntrack.c
> index 8a7056bac..5786424f6 100644
> --- a/lib/conntrack.c
> +++ b/lib/conntrack.c
> @@ -2651,25 +2651,19 @@ 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;
> }
> diff --git a/lib/conntrack.h b/lib/conntrack.h
> index ee7da099e..aa12a1847 100644
> --- a/lib/conntrack.h
> +++ b/lib/conntrack.h
> @@ -109,6 +109,7 @@ struct conntrack_dump {
> union {
> struct cmap_position cm_pos;
cm_pos is now dead code.
> struct hmap_position hmap_pos;
> + struct cmap_cursor cursor;
> };
> bool filter_zone;
> uint16_t zone;
> diff --git a/tests/system-traffic.at b/tests/system-traffic.at
> index 98e494abf..34f93b2e5 100644
> --- a/tests/system-traffic.at
> +++ b/tests/system-traffic.at
> @@ -8389,6 +8389,53 @@ 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"
> +
> +for i in $(seq 1 20); do
> + frame=$(ovs-ofctl compose-packet --bare "$flow_l3, udp_src=1,udp_dst=$i")
> + AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 "in_port=1
> packet=$frame actions=resubmit(,0)"])
> +done
> +frame=$(ovs-ofctl compose-packet --bare "$flow_l3, udp_src=2,udp_dst=1")
> +AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 "in_port=1 packet=$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 | 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 'ct_nw_proto=17,ct_tp_src=1'])
> +AT_CHECK([ovs-appctl dpctl/dump-conntrack | 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])
> --
> 2.41.0
>
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