linux-cp: connectivity issue on stable/2602

[konradkreciwilk]

Environment

• VPP stable/2510: working
• VPP stable/2602: broken
• LCP with lcp-auto-subint, lcp-sync enabled
• Bond (LACP) with VLAN sub-interfaces

I have working configuration on stable/2510:

create bond mode lacp load-balance l34 numa-only id 100

bond add BondEthernet100 FortyGigabitEthernet1 long-timeout
#bond add BondEthernet100 FortyGigabitEthernet3 long-timeout

lcp create BondEthernet100 host-if be0

create sub-interfaces BondEthernet100 38

set interface mtu packet 1504 BondEthernet100
set interface mtu packet 1500 BondEthernet100.38

set interface state FortyGigabitEthernet1 up
set interface state FortyGigabitEthernet3 up

set interface state  BondEthernet100 up
set interface state  BondEthernet100.38 up

set interface ip address BondEthernet100.38 10.38.38.254/24


linux-cp {
  lcp-sync
  lcp-auto-subint
  del-static-on-link-down
  default netns dataplane
}

from linux, I able to ping host from BondEthernet100.38:

# ip netns exec dataplane ping 10.38.38.2
PING 10.38.38.2 (10.38.38.2) 56(84) bytes of data.
64 bytes from 10.38.38.2: icmp_seq=1 ttl=64 time=9.96 ms

after migration to stable/2602, the same configuration, does not work:

# ip netns exec dataplane ping 10.38.38.2
PING 10.38.38.2 (10.38.38.2) 56(84) bytes of data.

only arping is pingable

# ip netns exec dataplane arping 10.38.38.2
ARPING 10.38.38.2
60 bytes from 00:02:c9:42:cd:b0 (10.38.38.2): index=0 time=9.957 msec

tcpdump shows that flow goes out, but do not see and the other end.

Ping from vppctl works well:

vppctl ping 10.38.38.2
116 bytes from 10.38.38.2: icmp_seq=1 ttl=64 time=11.3647 ms

Conclusion

LCP punt mechanism for locally destined packets on sub-interfaces appears broken in 26.02.
Packets reach VPP (ARP works, vppctl ping works) but are not punted to Linux tap interface.