Bug 1791190

+++ This bug was initially created as a clone of Bug #1775525 +++

Description of problem:
After guest send a malformed arp, it can't ping other host through a logical router

Version-Release number of selected component (if applicable):
[root@dell-per730-57 multicast]# rpm -qa|grep openvs
openvswitch-selinux-extra-policy-1.0-14.el7fdp.noarch
openvswitch2.11-2.11.0-26.el7fdp.x86_64
[root@dell-per730-57 multicast]# rpm -qa|grep ovn
ovn2.11-2.11.1-20.el7fdp.x86_64
ovn2.11-central-2.11.1-20.el7fdp.x86_64
ovn2.11-host-2.11.1-20.el7fdp.x86_64


How reproducible:
everytime 

Steps to Reproduce:
topo
         hv1_v1
           |
hv1_vm0---S2----r1-----public(ls)
                |
     hv0_vm0---S3---vm2

1. setup a env of the topo above(or run the case ovn_test_nat to get the env)
[root@dell-per730-19 multicast]# ovn-nbctl show
switch b726549c-4249-4e34-8300-c62f1cbc6ca1 (s2)
    port hv1_vm01_vnet1
        addresses: ["00:de:ad:01:01:01 172.16.102.12"]
    port hv1_vm00_vnet1
        addresses: ["00:de:ad:01:00:01 172.16.102.11"]
    port s2_r1
        type: router
        addresses: ["00:de:ad:ff:01:02 172.16.102.1"]
        router-port: r1_s2
switch 67056c80-7d36-4730-9036-fd4fb5d29310 (public)
    port ln_p1
        type: localnet
        addresses: ["unknown"]
    port public_r1
        type: router
        router-port: r1_public
switch c8f319ef-4db1-4964-aefd-b5288ad1b652 (s3)
    port hv0_vm00_vnet1
        addresses: ["00:de:ad:00:00:01 172.16.103.11"]
    port vm2
        addresses: ["00:00:00:00:00:02"]
    port s3_r1
        type: router
        addresses: ["00:de:ad:ff:01:03 172.16.103.1"]
        router-port: r1_s3
    port hv0_vm01_vnet1
        addresses: ["00:de:ad:00:01:01 172.16.103.12"]
router 964bb90a-f52c-4fae-ba32-520da109b83b (r1)
    port r1_public
        mac: "40:44:00:00:00:03"
        networks: ["172.16.104.1/24"]
    port r1_s2
        mac: "00:de:ad:ff:01:02"
        networks: ["172.16.102.1/24"]
    port r1_s3
        mac: "00:de:ad:ff:01:03"
        networks: ["172.16.103.1/24"]
    nat 2f3e76c8-ab37-4345-b84c-bcea8f3ec231
        external ip: "172.16.104.200"
        logical ip: "172.16.102.11"
        type: "dnat_and_snat"
    nat dbc3612c-bc65-4221-b52b-d29aa7ed7a4b
        external ip: "172.16.104.201"
        logical ip: "172.16.103.11"
        type: "dnat_and_snat"

2. after this step,ping from vm2 to hv0_vm0/hv1_vm0/hv1_vm1 all pass.
ip netns exec vm2 ping 172.16.102.11 -c 3'
PING 172.16.102.11 (172.16.102.11) 56(84) bytes of data.
64 bytes from 172.16.102.11: icmp_seq=1 ttl=63 time=1.24 ms
64 bytes from 172.16.102.11: icmp_seq=2 ttl=63 time=0.294 ms
64 bytes from 172.16.102.11: icmp_seq=3 ttl=63 time=0.230 ms

--- 172.16.102.11 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms

3. send a malformed arp packets from vm2
from scapy.all import *

sendp(Ether(src="00:de:ad:01:00:01", dst="ff:ff:ff:ff:ff:ff")/ARP(op=1,hwsrc='00:de:ad:01:00:01',hwdst='00:00:00:00:00:00',psrc='172.16.103.13',pdst='0.0.0.0'),iface="vm2")

4. from vm2 to hv0_vm0/hv1_vm0/hv1_vm1,only to hv0_vm0 pass.
vm2 can't communicate hosts through router.
ping the ip of the router also failed.
ip netns exec vm2 ping 172.16.102.11 -c 3'
PING 172.16.102.11 (172.16.102.11) 56(84) bytes of data.

--- 172.16.102.11 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 1999ms
ip netns exec vm2 ping 172.16.103.1 -c 3'
PING 172.16.103.1 (172.16.103.1) 56(84) bytes of data.

--- 172.16.103.1 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 1999ms


Actual results:
ping failed

Expected results:
ping pass

Additional info:

--- Additional comment from ying xu on 2019-11-22 07:58:55 UTC ---