[ovs-discuss] ovn: unsnat handling error for Distributed Gateway

[Guoshuai Li]

Hi All, I am having a problem for ovn and need help, thanks.


I created two logical routes and connected the two LogicalRoutes through 
a external LogicalSwitch (connected to the external network) .

And then LogicalRoute-1 connected to the VM through the internal 
LogicalSwitch .

my topology:

                       10.157.142.3              172.16.1.254
                            +--------------------+ 
+---------+--------+                   +---------+--------+
           +----------------+  Logical Router 1 +------------------|  
Logical Switch  +-------------------+ VM 172.16.1.7   |
           |                +--------------------+ 
+------------------+                   +------------------+
+---------+--------+
|  Logical Switch  |
+------------------+
           |                +--------------------+
           +----------------+  Logical Router 2  |
                            +--------------------+
                       10.157.142.3

I tested the master and Branch2.7, it Can not be transferred from VM 
(172.16.1.7) to LogicaRouter-2 's port (10.157.142.3) via ping.
My logical router is a distributed gateway, and the two logical router 
ports that connect external LogicalSwitch are on the same chassis.
If the two logical router ports are not on the same chassis ping is also 
OK, And ping from VM (172.16.1.7) to external network is also OK.

I looked at the openflow tables on gateway chassis,  I suspected unsnat 
handling error in Router1 input for icmp replay.
I think it is necessary to replace the destination address 10.157.142.3 
with 172.16.1.7 in Table 19 and route 172.16.1.7 in Table 21, but now 
the route match is 10.157.142.0/24.

cookie=0x92bd0055, duration=68.468s, table=16, n_packets=1, n_bytes=98, 
idle_age=36, priority=50,reg14=0x4,metadata=0x7,dl_dst=fa:16:3e:58:1c:8a 
actions=resubmit(,17)
cookie=0x45765344, duration=68.467s, table=17, n_packets=1, n_bytes=98, 
idle_age=36, priority=0,metadata=0x7 actions=resubmit(,18)
cookie=0xaeaaed29, duration=68.479s, table=18, n_packets=1, n_bytes=98, 
idle_age=36, priority=0,metadata=0x7 actions=resubmit(,19)
cookie=0xce785d51, duration=68.479s, table=19, n_packets=1, n_bytes=98, 
idle_age=36, priority=100,ip,reg14=0x4,metadata=0x7,nw_dst=10.157.142.3 
actions=ct(table=20,zone=NXM_NX_REG12[0..15],nat)
cookie=0xbd994421, duration=68.481s, table=20, n_packets=1, n_bytes=98, 
idle_age=36, priority=0,metadata=0x7 actions=resubmit(,21)
cookie=0xaea3a6ae, duration=68.479s, table=21, n_packets=1, n_bytes=98, 
idle_age=36, priority=49,ip,metadata=0x7,nw_dst=10.157.142.0/24 
actions=dec_ttl(),move:NXM_OF_IP_DST[]->NXM_NX_XXREG0[96..127],load:0xa9d8e03->NXM_NX_XXREG0[64..95],mod_dl_src:fa:16:3e:58:1c:8a,load:0x4->NXM_NX_REG15[],load:0x1->NXM_NX_REG10[0],resubmit(,22)
cookie=0xce6e8d4e, duration=68.482s, table=22, n_packets=1, n_bytes=98, 
idle_age=36, priority=0,ip,metadata=0x7 
actions=push:NXM_NX_REG0[],push:NXM_NX_XXREG0[96..127],pop:NXM_NX_REG0[],mod_dl_dst:00:00:00:00:00:00,resubmit(,66),pop:NXM_NX_REG0[],resubmit(,23)
cookie=0xce89c4ed, duration=68.481s, table=23, n_packets=1, n_bytes=98, 
idle_age=36, 
priority=150,reg15=0x4,metadata=0x7,dl_dst=00:00:00:00:00:00 
actions=load:0x5->NXM_NX_REG15[],resubmit(,24)
cookie=0xb2d84350, duration=68.469s, table=24, n_packets=1, n_bytes=98, 
idle_age=36, priority=100,ip,metadata=0x7,dl_dst=00:00:00:00:00:00

I do not know why and need help, thanks.