On Wed, May 20, 2026 at 11:03 PM Dumitru Ceara <[email protected]> wrote:

> On 5/20/26 4:03 PM, Dumitru Ceara wrote:
> > Hi Ales, Mark,
>

Hi Mark and Dumitru,

thank you for the review.


> >
> > On 5/19/26 9:39 PM, Mark Michelson wrote:
> >> Thanks Ales,
> >>
> >> Acked-by: Mark Michelson <[email protected]>
> >>
> >
> > Thanks for the patch and review, I have a few (minor) comments myself:
> >
> >> On Wed, May 13, 2026 at 3:04 AM Ales Musil via dev
> >> <[email protected]> wrote:
> >>>
> >>> When LRP is configured with multiple IPs we could have MAC Bindings
> >>> with IP addresses corresponding to any of the LRP subnets. However,
> >>> the refresh mechanism would just choose the first IP as source.
> >>> That could cause confusion for the switches along the way and it
> >>> could also be dropped along the way. Make sure we always select
> >>> the right IP. The linear lookup shouldn't cause any performance
> >>> issues as in the practice there isn't too many IPs per LRP.
> >>>
> >>> Reported-at: https://redhat.atlassian.net/browse/FDP-3784
> >>> Fixes: 1e4d4409f391 ("controller: Send ARP/ND for stale mac_bindings
> entries.")
> >>> Assisted-by: Claude Opus 4.6, Claude Code
> >>> Signed-off-by: Ales Musil <[email protected]>
> >>> ---
> >>>  controller/mac-cache.c |  28 +++++++---
> >>>  tests/ovn.at           | 113
> +++++++++++++++++++++++++++++++++++++++++
> >>>  2 files changed, 135 insertions(+), 6 deletions(-)
> >>>
> >>> diff --git a/controller/mac-cache.c b/controller/mac-cache.c
> >>> index bdf35eeb7..108d93f97 100644
> >>> --- a/controller/mac-cache.c
> >>> +++ b/controller/mac-cache.c
> >>> @@ -920,13 +920,29 @@ mac_binding_probe_stats_run(struct vector
> *stats_vec, uint64_t *req_delay,
> >>>              continue;
> >>>          }
> >>>
> >>> -        bool is_mb_v4 = IN6_IS_ADDR_V4MAPPED(&mb->data.ip);
> >>> -        if ((is_mb_v4 && laddr.n_ipv4_addrs)
> >>> -                || (!is_mb_v4 && laddr.n_ipv6_addrs)) {
> >>> -            struct in6_addr local =
> >>> -                is_mb_v4 ?
> in6_addr_mapped_ipv4(laddr.ipv4_addrs[0].addr)
> >>> -                         : laddr.ipv6_addrs[0].addr;
> >>> +        struct in6_addr local = in6addr_any;
> >>> +        if (IN6_IS_ADDR_V4MAPPED(&mb->data.ip)) {
> >>> +            ovs_be32 ip4 = in6_addr_get_mapped_ipv4(&mb->data.ip);
> >>> +            for (size_t i = 0; i < laddr.n_ipv4_addrs; i++) {
> >>> +                struct ipv4_netaddr address = laddr.ipv4_addrs[i];
> >>> +                if (address.network == (ip4 & address.mask)) {
> >>> +                    local = in6_addr_mapped_ipv4(address.addr);
> >>> +                    break;
> >>> +                }
> >>> +            }
> >>> +        } else {
> >>> +            for (size_t i = 0; i < laddr.n_ipv6_addrs; i++) {
> >>> +                struct ipv6_netaddr address = laddr.ipv6_addrs[i];
> >>> +                struct in6_addr neigh_prefix =
> >>> +                    ipv6_addr_bitand(&mb->data.ip, &address.mask);
> >>> +                if (ipv6_addr_equals(&address.network,
> &neigh_prefix)) {
> >>> +                    local = address.addr;
> >>> +                    break;
> >>> +                }
> >>> +            }
> >>> +        }
> >>>
> >>> +        if (!ipv6_addr_equals(&local, &in6addr_any)) {
> >>>              mac_binding_update_log("Sending ARP/ND request for
> active",
> >>>                                     &mb->data, true, threshold,
> >>>                                     stats->idle_age_ms,
> since_updated_ms);
> >>> diff --git a/tests/ovn.at b/tests/ovn.at
> >>> index 2914d0e64..cd849f4db 100644
> >>> --- a/tests/ovn.at
> >>> +++ b/tests/ovn.at
> >>> @@ -37258,6 +37258,119 @@ OVN_CLEANUP([hv1])
> >>>  AT_CLEANUP
> >>>  ])
> >>>
> >>> +OVN_FOR_EACH_NORTHD([
> >>> +AT_SETUP([MAC binding aging - probing multi-subnet source IP])
> >>> +AT_SKIP_IF([test $HAVE_SCAPY = no])
> >>> +ovn_start
> >>> +
> >>> +aging_th=10
> >>> +net_add n1
> >>> +sim_add hv1
> >>> +as hv1
> >>> +check ovs-vsctl add-br br-phys
> >>> +ovn_attach n1 br-phys 192.168.0.1
> >>> +ovn-appctl -t ovn-controller vlog/set mac_cache:file:dbg
> pinctrl:file:dbg
> >>> +
> >>> +check ovn-nbctl
>        \
> >>> +    -- ls-add ls1
>        \
> >>> +    -- lr-add lr
>       \
> >>> +    -- set logical_router lr
> options:mac_binding_age_threshold=$aging_th    \
> >>> +    -- lrp-add lr lr-ls1 00:00:00:00:10:00 10.10.10.1/24
> 42.42.42.1/24      \
> >>> +       fd11::1/64 fd12::1/64
>       \
> >>> +    -- lsp-add-router-port ls1 ls1-lr lr-ls1
>       \
> >>> +    -- lsp-add ls1 vif1
>        \
> >>> +    -- lsp-set-addresses vif1 "unknown"
> >>> +
> >>> +check ovs-vsctl
>        \
> >>> +    -- add-port br-int vif1
>        \
> >>> +    -- set interface vif1 external-ids:iface-id=vif1
>       \
> >>> +    options:tx_pcap=hv1/vif1-tx.pcap options:rxq_pcap=hv1/vif1-rx.pcap
> >>> +
> >>> +OVN_POPULATE_ARP
> >>> +wait_for_ports_up
> >>> +check ovn-nbctl --wait=hv sync
> >>> +
> >>> +# Wait for pinctrl thread to be connected.
> >>> +OVS_WAIT_UNTIL([grep pinctrl hv1/ovn-controller.log | grep -q
> connected])
> >>> +
> >>> +# Create MAC bindings in both IPv4 subnets.
> >>> +send_garp hv1 vif1 2 00:00:00:00:10:1a ff:ff:ff:ff:ff:ff 10.10.10.100
> 10.10.10.100
> >>> +wait_row_count mac_binding 1 ip="10.10.10.100" logical_port="lr-ls1"
> >>> +
> >>> +send_garp hv1 vif1 2 00:00:00:00:10:1b ff:ff:ff:ff:ff:ff 42.42.42.253
> 42.42.42.253
> >>> +wait_row_count mac_binding 1 ip="42.42.42.253" logical_port="lr-ls1"
> >>> +
> >>> +# Create MAC bindings in both IPv6 subnets.
> >>> +send_na hv1 vif1 00:00:00:00:10:1a 00:00:00:00:10:00 fd11::64 fd11::1
> >>> +wait_row_count mac_binding 1 ip=\"fd11::64\" logical_port=\"lr-ls1\"
> >>> +
> >>> +send_na hv1 vif1 00:00:00:00:10:1b 00:00:00:00:10:00 fd12::64 fd12::1
> >>> +wait_row_count mac_binding 1 ip=\"fd12::64\" logical_port=\"lr-ls1\"
> >>> +
> >>> +# Record UUIDs for all MAC bindings.
> >>> +uuid_v4_1=$(fetch_column Mac_Binding _uuid ip=10.10.10.100)
> >>> +uuid_v4_2=$(fetch_column Mac_Binding _uuid ip=42.42.42.253)
> >>> +uuid_v6_1=$(fetch_column Mac_Binding _uuid ip=\"fd11::64\")
> >>> +uuid_v6_2=$(fetch_column Mac_Binding _uuid ip=\"fd12::64\")
> >>> +
> >>> +# Send IPv4 and IPv6 UDP traffic to refresh entries in
> OFTABLE_MAC_BINDING.
> >>> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a 42.42.42.253
> 10.10.10.100
> >>> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b 10.10.10.100
> 42.42.42.253
> >>> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a fd12::64
> fd11::64
> >>> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b fd11::64
> fd12::64
> >>> +
> >>> +OVS_WAIT_UNTIL([$(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_BINDING | \
> >>> +                  sed
> 's/reg15=0x.,metadata=0x./reg15=<cleared>,metadata=<cleared>/g' | \
> >>> +                  grep -q
> "reg0=0xa0a0a64,reg15=<cleared>,metadata=<cleared>
> actions=mod_dl_dst:00:00:00:00:10:1a")])
> >>> +OVS_WAIT_UNTIL([$(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_BINDING | \
> >>> +                  sed
> 's/reg15=0x.,metadata=0x./reg15=<cleared>,metadata=<cleared>/g' | \
> >>> +                  grep -q
> "reg0=0x2a2a2afd,reg15=<cleared>,metadata=<cleared>
> actions=mod_dl_dst:00:00:00:00:10:1b")])
> >
> > Spotted by my "tiny little AI helper", quoting:
> >
> > Nit (test): The OVS_WAIT_UNTIL calls use OVS_WAIT_UNTIL([$(... | grep -q
> > ...)]). The $() command substitution captures empty stdout (since grep
> > -q is used) and evaluates the empty result as a command, which always
> > succeeds. The correct pattern would be OVS_WAIT_UNTIL([ovs-ofctl
> > dump-flows ... | sed ... | grep -q ...]) without the $() wrapper. Same
> > issue exists in the adjacent test (pre-existing).
> >
> >>> +
> >>> +# Wait until all entries in OFTABLE_MAC_CACHE_USE are stale.
> >>> +OVS_WAIT_UNTIL([test $(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_CACHE_USE | \
> >>> +                       awk '/nw_src=10.10.10.100/{print
> <http://10.10.10.100/%7Bprint> substr($6,10,1)}') -ge $((aging_th/2))])
> >>> +OVS_WAIT_UNTIL([test $(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_CACHE_USE | \
> >>> +                       awk '/nw_src=42.42.42.253/{print
> <http://42.42.42.253/%7Bprint> substr($6,10,1)}') -ge $((aging_th/2))])
> >>> +OVS_WAIT_UNTIL([test $(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_CACHE_USE | \
> >>> +                       awk '/ipv6_src=fd11::64/{print
> substr($6,10,1)}') -ge $((aging_th/2))])
> >>> +OVS_WAIT_UNTIL([test $(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_CACHE_USE | \
> >>> +                       awk '/ipv6_src=fd12::64/{print
> substr($6,10,1)}') -ge $((aging_th/2))])
> >>> +
> >>> +# Send traffic to trigger probing for all entries.
> >>> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a 42.42.42.253
> 10.10.10.100
> >>> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b 10.10.10.100
> 42.42.42.253
> >>> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a fd12::64
> fd11::64
> >>> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b fd11::64
> fd12::64
> >>> +
> >>> +# Verify ARP probes use the correct source IPs from matching subnets.
> >>> +# ARP for 10.10.10.100 must use source IP 10.10.10.1 (first subnet).
> >>> +dump_arp 1 00:00:00:00:10:00 ff:ff:ff:ff:ff:ff 10.10.10.1
> 10.10.10.100 00:00:00:00:00:00 > expected
> >>> +# ARP for 42.42.42.253 must use source IP 42.42.42.1 (second subnet).
> >>> +dump_arp 1 00:00:00:00:10:00 ff:ff:ff:ff:ff:ff 42.42.42.1
> 42.42.42.253 00:00:00:00:00:00 >> expected
> >>> +OVN_CHECK_PACKETS_CONTAIN([hv1/vif1-tx.pcap], [expected])
> >>> +
> >>> +# Verify NS probes use the correct source IPs from matching subnets.
> >>> +# NS for fd11::64 must use source IP fd11::1 (first IPv6 subnet).
> >>> +dump_ns 33:33:ff:00:00:64 00:00:00:00:10:00 ff02::1:ff00:64 fd11::1
> fd11::64 > expected_v6
> >>> +# NS for fd12::64 must use source IP fd12::1 (second IPv6 subnet).
> >>> +dump_ns 33:33:ff:00:00:64 00:00:00:00:10:00 ff02::1:ff00:64 fd12::1
> fd12::64 >> expected_v6
> >>> +OVN_CHECK_PACKETS_CONTAIN([hv1/vif1-tx.pcap], [expected_v6])
> >
> > There's a race here, I think, this failed in CI in my fork:
> >
> https://github.com/dceara/ovn/actions/runs/26164612950/job/76965765667#step:12:5323
> >
> >>> +
> >>> +# Send ARP/NA replies and check MAC_Binding UUIDs remain consistent.
> >>> +send_garp hv1 vif1 2 00:00:00:00:10:1a 00:00:00:00:10:00 10.10.10.100
> 10.10.10.1
> >>> +send_garp hv1 vif1 2 00:00:00:00:10:1b 00:00:00:00:10:00 42.42.42.253
> 42.42.42.1
> >>> +send_na hv1 vif1 00:00:00:00:10:1a 00:00:00:00:10:00 fd11::64 fd11::1
> >>> +send_na hv1 vif1 00:00:00:00:10:1b 00:00:00:00:10:00 fd12::64 fd12::1
> >>> +
> >>> +AT_CHECK([test "$(fetch_column Mac_Binding _uuid ip=10.10.10.100)" =
> "$uuid_v4_1"])
> >>> +AT_CHECK([test "$(fetch_column Mac_Binding _uuid ip=42.42.42.253)" =
> "$uuid_v4_2"])
> >>> +AT_CHECK([test "$(fetch_column Mac_Binding _uuid ip=\"fd11::64\")" =
> "$uuid_v6_1"])
> >>> +AT_CHECK([test "$(fetch_column Mac_Binding _uuid ip=\"fd12::64\")" =
> "$uuid_v6_2"])
> >>> +
> >>> +OVN_CLEANUP([hv1])
> >>> +AT_CLEANUP
> >>> +])
> >>> +
>
> FWIW, my "tiny little AI helper" suggested the following incremental
> which makes sense to me (it's also what we do in the other mac binding
> probing test):
>
> diff --git a/tests/ovn.at b/tests/ovn.at
> index c1d3a7b80d..135b38750d 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -37312,17 +37312,20 @@ uuid_v6_1=$(fetch_column Mac_Binding _uuid
> ip=\"fd11::64\")
>  uuid_v6_2=$(fetch_column Mac_Binding _uuid ip=\"fd12::64\")
>
>  # Send IPv4 and IPv6 UDP traffic to refresh entries in
> OFTABLE_MAC_BINDING.
> -send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a 42.42.42.253
> 10.10.10.100
> -send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b 10.10.10.100
> 42.42.42.253
> -send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a fd12::64 fd11::64
> -send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b fd11::64 fd12::64
> +# Use different src MACs than the ones from GARP/NA to avoid resetting
> +# OFTABLE_MAC_CACHE_USE idle_age (which would keep the timestamp fresh
> +# and suppress probing via the cooldown mechanism).
> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2a 42.42.42.253
> 10.10.10.100
> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2b 10.10.10.100
> 42.42.42.253
> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2a fd12::64 fd11::64
> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2b fd11::64 fd12::64
>
> -OVS_WAIT_UNTIL([$(ovs-ofctl dump-flows br-int table=OFTABLE_MAC_BINDING |
> \
> +OVS_WAIT_UNTIL([ovs-ofctl dump-flows br-int table=OFTABLE_MAC_BINDING | \
>                    sed
> 's/reg15=0x.,metadata=0x./reg15=<cleared>,metadata=<cleared>/g' | \
> -                  grep -q
> "reg0=0xa0a0a64,reg15=<cleared>,metadata=<cleared>
> actions=mod_dl_dst:00:00:00:00:10:1a")])
> -OVS_WAIT_UNTIL([$(ovs-ofctl dump-flows br-int table=OFTABLE_MAC_BINDING |
> \
> +                  grep -q
> "reg0=0xa0a0a64,reg15=<cleared>,metadata=<cleared>
> actions=mod_dl_dst:00:00:00:00:10:1a"])
> +OVS_WAIT_UNTIL([ovs-ofctl dump-flows br-int table=OFTABLE_MAC_BINDING | \
>                    sed
> 's/reg15=0x.,metadata=0x./reg15=<cleared>,metadata=<cleared>/g' | \
> -                  grep -q
> "reg0=0x2a2a2afd,reg15=<cleared>,metadata=<cleared>
> actions=mod_dl_dst:00:00:00:00:10:1b")])
> +                  grep -q
> "reg0=0x2a2a2afd,reg15=<cleared>,metadata=<cleared>
> actions=mod_dl_dst:00:00:00:00:10:1b"])
>
>  # Wait until all entries in OFTABLE_MAC_CACHE_USE are stale.
>  OVS_WAIT_UNTIL([test $(ovs-ofctl dump-flows br-int
> table=OFTABLE_MAC_CACHE_USE | \
> @@ -37335,10 +37338,11 @@ OVS_WAIT_UNTIL([test $(ovs-ofctl dump-flows
> br-int table=OFTABLE_MAC_CACHE_USE |
>                         awk '/ipv6_src=fd12::64/{print substr($6,10,1)}')
> -ge $((aging_th/2))])
>
>  # Send traffic to trigger probing for all entries.
> -send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a 42.42.42.253
> 10.10.10.100
> -send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b 10.10.10.100
> 42.42.42.253
> -send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1a fd12::64 fd11::64
> -send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:1b fd11::64 fd12::64
> +# Again use different src MACs to only hit OFTABLE_MAC_BINDING (not
> MAC_CACHE_USE).
> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2a 42.42.42.253
> 10.10.10.100
> +send_udp hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2b 10.10.10.100
> 42.42.42.253
> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2a fd12::64 fd11::64
> +send_udp6 hv1 vif1 00:00:00:00:10:00 00:00:00:00:10:2b fd11::64 fd12::64
>
>  # Verify ARP probes use the correct source IPs from matching subnets.
>  # ARP for 10.10.10.100 must use source IP 10.10.10.1 (first subnet).
>

I have applied to diff in v2. It seems to work as I didn't see a single
failure
while running it in a loop.


> ---
>
> Regards,
> Dumitru
>
>
Regards,
Ales
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