How to trace OVN logical Flow trace with associated OVS OpenFlow rules in the OVN integrated environment?

Solution Verified - Updated -

Environment

  • Red Hat OpenStack 13
  • OpenvSwitch 2.9
  • python-networking-ovn-4.0.3-3

Issue

  • In OpenStack and ML2-OVN integrated environment, how to trace OVN logical Flow trace with associated OVS OpenFlow rules?

Resolution

  • This ovn-trace utility simulates packet forwarding within an OVN logical network.
  • ovn-trace works by reading the Logical_Flow and other tables from the OVN southbound database. It simulates a packet’s path through logical networks by repeatedly looking it up in the logical flow table, following the entire tree of possibilities.
  • In a typical scenario, ovn-trace is to provide datapath and microflow arguments on the command line.

    SYNOPSIS

    ovn-trace [options] datapath microflow
    
    • The datapath argument specifies the name of a logical datapath. Acceptable names are the name from the northbound Logical_Switch or Logical_Router table, the UUID of a record from one of those tables, or the UUID of a record from the southbound Datapath_Binding table.
    • The microflow argument describes the packet whose forwarding is to be simulated, in the syntax of an OVN logical expression, as described in man ovn-sb, to express constraints.
  • Refer the following command to get more ovn-trace option: # man ovn-trace.

  • In OpenStack cloud management systems, human-unfriendly names for ports and datapaths, for example, ones that include entire UUIDs. OVN does usually include friendlier names, but the long, hard-to-read names are the ones that appear in matches and actions. By default, or with --friendly-names, ovn-trace substitutes these friendlier names for the long names in its output. Use --no-friendly-names to disable this behavior; this option might be useful, for example, if a program is going to parse ovn-trace output.
  • Makes ovn-trace attempt to obtain and display the OpenFlow flows that correspond to each OVN logical flow. To do so, ovn-trace connects to remote with --ovs[=remote] over OpenFlow and retrieves the flows. If remote is specified, it must be an active OpenFlow connection method described in man ovs-ofctl.
  • To make it easier ovn-trace command locally can execute in compute node to review the logical flow trace and associated OpenFlow flows with --ovs option since default integration socket file unix:/var/run/openvswitch/br-int.mgmt resides in the same system.

Example: Details from the Lab

  1. Packet trace scenario from VM internal port to the external gateway where the instance associated with Floating IP with ACL policies.

    $ openstack server list --long --fit-width
    +-----------------------+-----------+--------+------------+-------------+-----------------------+------------+-----------------------+-------------+-----------------------+-------------------+---------------------------+------------+
    | ID                    | Name      | Status | Task State | Power State | Networks              | Image Name | Image ID              | Flavor Name | Flavor ID             | Availability Zone | Host                      | Properties |
    +-----------------------+-----------+--------+------------+-------------+-----------------------+------------+-----------------------+-------------+-----------------------+-------------------+---------------------------+------------+
    | 7482575f-6cf5-41de-b7 | instance1 | ACTIVE | None       | Running     | internal1=2001::f816: | cirros     | 5d1f2e8d-1d3d-429a-   | m1.medium   | fae9f759-f651-4512-b3 | nova              | ovn-compute-1.localdomain |            |
    | 13-c50a939664f4       |           |        |            |             | 3eff:febb:7e52,       |            | 9d73-7edb7f575952     |             | b7-3e03603bae51       |                   |                           |            |
    |                       |           |        |            |             | 192.168.1.6,          |            |                       |             |                       |                   |                           |            |
    |                       |           |        |            |             | 10.74.167.210         |            |                       |             |                       |                   |                           |            |
    +-----------------------+-----------+--------+------------+-------------+-----------------------+------------+-----------------------+-------------+-----------------------+-------------------+---------------------------+------------+
    
    $ nova interface-list instance1
    +------------+--------------------------------------+--------------------------------------+---------------------------------------+-------------------+
    | Port State | Port ID                              | Net ID                               | IP addresses                          | MAC Addr          |
    +------------+--------------------------------------+--------------------------------------+---------------------------------------+-------------------+
    | ACTIVE     | 45b37972-88ad-4f9f-884d-50120fcebc39 | 250d6622-eec8-4471-ae89-3eb0302be2e2 | 192.168.1.6,2001::f816:3eff:febb:7e52 | fa:16:3e:bb:7e:52 |
    +------------+--------------------------------------+--------------------------------------+---------------------------------------+-------------------+
    
    $ neutron router-port-list router1
    neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead.
    +--------------------------------------+------+----------------------------------+-------------------+--------------------------------------------------------------------------------------+
    | id                                   | name | tenant_id                        | mac_address       | fixed_ips                                                                            |
    +--------------------------------------+------+----------------------------------+-------------------+--------------------------------------------------------------------------------------+
    | 26aa8fb5-1259-4350-ad41-688434f4734a |      | 9bfb1590ceb94d5ca78b99f7c79994b2 | fa:16:3e:30:ed:9b | {"subnet_id": "fb81d894-5dc8-418e-80fb-bc3e5face00a", "ip_address": "192.168.1.1"}   |
    | b7db6753-1d91-4a9e-ac37-b62b60f1efcf |      | 9bfb1590ceb94d5ca78b99f7c79994b2 | fa:16:3e:55:9d:5e | {"subnet_id": "42c9fb04-515e-4070-9ee8-ad885ba1388d", "ip_address": "2001::1"}       |
    | ef37243a-ac26-4c00-8c84-ebd90d6bb373 |      |                                  | fa:16:3e:71:74:11 | {"subnet_id": "691ca54f-12c7-4cbf-977d-13f2e7e3f489", "ip_address": "10.74.167.213"} |
    +--------------------------------------+------+----------------------------------+-------------------+--------------------------------------------------------------------------------------+
    
  2. Login to Compute nodes where the associated instance is running and set the South Bound socket in the environment variable.

    export SB=$(sudo ovs-vsctl get open . external_ids:ovn-remote | sed -e 's/\"//g')
    export NB=$(sudo ovs-vsctl get open . external_ids:ovn-remote | sed -e 's/\"//g' | sed -e 's/6642/6641/g')
    alias ovn-sbctl='sudo docker exec ovn_controller ovn-sbctl --db=$SB'
    alias ovn-nbctl='sudo docker exec ovn_controller ovn-nbctl --db=$NB'
    alias ovn-trace='sudo docker exec ovn_controller ovn-trace --db=$SB'
    
  3. With the above reference details, the ovn-trace can trace the logical and associated OF rules from VM internal port to the external gateway.

    Sample output from lab

    # ovn-trace --no-friendly-names --ovs neutron-250d6622-eec8-4471-ae89-3eb0302be2e2 'inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && eth.src == fa:16:3e:bb:7e:52 &&  eth.dst == fa:16:3e:30:ed:9b && ip4.src == 192.168.1.6 && ip4.dst == 10.74.167.222 && ip.ttl == 64 && icmp4.type == 8'
    # icmp,reg14=0x4,vlan_tci=0x0000,dl_src=fa:16:3e:bb:7e:52,dl_dst=fa:16:3e:30:ed:9b,nw_src=192.168.1.6,nw_dst=10.74.167.222,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
    
    ingress(dp="019353ef-1517-4bfe-b244-d85d5c449721", inport="45b37972-88ad-4f9f-884d-50120fcebc39")
    -------------------------------------------------------------------------------------------------
     0. ls_in_port_sec_l2 (ovn-northd.c:3867): inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && eth.src == {fa:16:3e:bb:7e:52}, priority 50, uuid d1dce7a9
        cookie=0xd1dce7a9, duration=251129.966s, table=8, n_packets=542, n_bytes=66717, priority=50,reg14=0x4,metadata=0xa,dl_src=fa:16:3e:bb:7e:52 actions=resubmit(,9)
        next;
     1. ls_in_port_sec_ip (ovn-northd.c:2849): inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && eth.src == fa:16:3e:bb:7e:52 && ip4.src == {192.168.1.6}, priority 90, uuid 4af885b6
        cookie=0x4af885b6, duration=251129.966s, table=9, n_packets=500, n_bytes=64165, priority=90,ip,reg14=0x4,metadata=0xa,dl_src=fa:16:3e:bb:7e:52,nw_src=192.168.1.6 actions=resubmit(,10)
        next;
     3. ls_in_pre_acl (ovn-northd.c:3150): ip, priority 100, uuid a71014c0
        cookie=0xa71014c0, duration=251135.800s, table=11, n_packets=4, n_bytes=360, priority=100,ipv6,metadata=0xa actions=load:0x1->NXM_NX_XXREG0[96],resubmit(,12)
        cookie=0xa71014c0, duration=251135.800s, table=11, n_packets=548, n_bytes=70155, priority=100,ip,metadata=0xa actions=load:0x1->NXM_NX_XXREG0[96],resubmit(,12)
        reg0[0] = 1;
        next;
     5. ls_in_pre_stateful (ovn-northd.c:3287): reg0[0] == 1, priority 100, uuid 8f3c5a49
        cookie=0x8f3c5a49, duration=251183.065s, table=13, n_packets=548, n_bytes=70155, priority=100,ip,reg0=0x1/0x1,metadata=0xa actions=ct(table=14,zone=NXM_NX_REG13[0..15])
        cookie=0x8f3c5a49, duration=251183.064s, table=13, n_packets=4, n_bytes=360, priority=100,ipv6,reg0=0x1/0x1,metadata=0xa actions=ct(table=14,zone=NXM_NX_REG13[0..15])
        ct_next;
    
    ct_next(ct_state=est|trk /* default (use --ct to customize) */)
    ---------------------------------------------------------------
     6. ls_in_acl (ovn-northd.c:3495): !ct.new && ct.est && !ct.rpl && ct_label.blocked == 0 && (inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && ip4), priority 2002, uuid d525e066
        cookie=0xd525e066, duration=251129.967s, table=14, n_packets=75, n_bytes=7610, priority=2002,ct_state=-new+est-rpl+trk,ct_label=0/0x1,ip,reg14=0x4,metadata=0xa actions=resubmit(,15)
        next;
    16. ls_in_l2_lkup (ovn-northd.c:4261): eth.dst == fa:16:3e:30:ed:9b, priority 50, uuid 35cc93a3
        cookie=0x35cc93a3, duration=251183.065s, table=24, n_packets=399, n_bytes=51793, priority=50,metadata=0xa,dl_dst=fa:16:3e:30:ed:9b actions=set_field:0x2->reg15,resubmit(,32)
        outport = "26aa8fb5-1259-4350-ad41-688434f4734a";
        output;
    
    egress(dp="019353ef-1517-4bfe-b244-d85d5c449721", inport="45b37972-88ad-4f9f-884d-50120fcebc39", outport="26aa8fb5-1259-4350-ad41-688434f4734a")
    ------------------------------------------------------------------------------------------------------------------------------------------------
     1. ls_out_pre_acl (ovn-northd.c:3109): ip && outport == "26aa8fb5-1259-4350-ad41-688434f4734a", priority 110, uuid af93b9cd
        cookie=0xaf93b9cd, duration=251135.800s, table=41, n_packets=399, n_bytes=51793, priority=110,ip,reg15=0x2,metadata=0xa actions=resubmit(,42)
        cookie=0xaf93b9cd, duration=251135.800s, table=41, n_packets=0, n_bytes=0, priority=110,ipv6,reg15=0x2,metadata=0xa actions=resubmit(,42)
        next;
     9. ls_out_port_sec_l2 (ovn-northd.c:4344): outport == "26aa8fb5-1259-4350-ad41-688434f4734a", priority 50, uuid d52c56d2
        cookie=0xd52c56d2, duration=251183.065s, table=49, n_packets=399, n_bytes=51793, priority=50,reg15=0x2,metadata=0xa actions=resubmit(,64)
        output;
        /* output to "26aa8fb5-1259-4350-ad41-688434f4734a", type "patch" */
    
    ingress(dp="99c15106-ee1e-4683-ad0d-2c0bdd52afcf", inport="lrp-26aa8fb5-1259-4350-ad41-688434f4734a")
    -----------------------------------------------------------------------------------------------------
     0. lr_in_admission (ovn-northd.c:4890): eth.dst == fa:16:3e:30:ed:9b && inport == "lrp-26aa8fb5-1259-4350-ad41-688434f4734a", priority 50, uuid fdcdfbae
        cookie=0xfdcdfbae, duration=251183.064s, table=8, n_packets=399, n_bytes=51793, priority=50,reg14=0x1,metadata=0xc,dl_dst=fa:16:3e:30:ed:9b actions=resubmit(,9)
        next;
     7. lr_in_ip_routing (ovn-northd.c:4472): ip4.dst == 10.74.167.208/28, priority 57, uuid fca6ccef
        cookie=0xfca6ccef, duration=251183.073s, table=15, n_packets=0, n_bytes=0, priority=57,ip,metadata=0xc,nw_dst=10.74.167.208/28 actions=dec_ttl(),move:NXM_OF_IP_DST[]->NXM_NX_XXREG0[96..127],load:0xa4aa7d5->NXM_NX_XXREG0[64..95],set_field:fa:16:3e:71:74:11->eth_src,set_field:0x5->reg15,load:0x1->NXM_NX_REG10[0],resubmit(,16)
        ip.ttl--;
        reg0 = ip4.dst;
        reg1 = 10.74.167.213;
        eth.src = fa:16:3e:71:74:11;
        outport = "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373";
        flags.loopback = 1;
        next;
     8. lr_in_arp_resolve (ovn-northd.c:6199): ip4, priority 0, uuid f6832489
        cookie=0xf6832489, duration=251183.065s, table=16, n_packets=398, n_bytes=51695, priority=0,ip,metadata=0xc actions=push:NXM_NX_REG0[],push:NXM_NX_XXREG0[96..127],pop:NXM_NX_REG0[],set_field:00:00:00:00:00:00->eth_dst,resubmit(,66),pop:NXM_NX_REG0[],resubmit(,17)
        get_arp(outport, reg0);
        /* MAC binding to f4:b5:2f:40:a6:81. */
        next;
     9. lr_in_gw_redirect (ovn-northd.c:6228): outport == "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373", priority 50, uuid e6dc2d72
        cookie=0xe6dc2d72, duration=251183.065s, table=17, n_packets=397, n_bytes=51610, priority=50,reg15=0x5,metadata=0xc actions=set_field:0x6->reg15,resubmit(,18)
        outport = "cr-lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373";
        next;
    10. lr_in_arp_request (ovn-northd.c:6306): 1, priority 0, uuid 7ad01353
        cookie=0x7ad01353, duration=251183.067s, table=18, n_packets=4186, n_bytes=451250, priority=0,metadata=0xc actions=resubmit(,32)
        output;
        /* Replacing type "chassisredirect" outport "cr-lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373" with distributed port "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373". */
    
    egress(dp="99c15106-ee1e-4683-ad0d-2c0bdd52afcf", inport="lrp-26aa8fb5-1259-4350-ad41-688434f4734a", outport="lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373")
    --------------------------------------------------------------------------------------------------------------------------------------------------------
     0. lr_out_undnat (ovn-northd.c:5575): ip && ip4.src == 192.168.1.6 && outport == "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373" && is_chassis_resident("cr-lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373"), priority 100, uuid b2c757eb
        cookie=0xb2c757eb, duration=251038.879s, table=40, n_packets=397, n_bytes=51610, priority=100,ip,reg15=0x5,metadata=0xc,nw_src=192.168.1.6 actions=ct(table=41,zone=NXM_NX_REG11[0..15],nat)
        ct_dnat;
    
    ct_dnat /* assuming no un-dnat entry, so no change */
    -----------------------------------------------------
     1. lr_out_snat (ovn-northd.c:5622): ip && ip4.src == 192.168.1.6 && outport == "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373" && is_chassis_resident("cr-lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373"), priority 33, uuid 907892ee
        cookie=0x907892ee, duration=251038.879s, table=41, n_packets=44, n_bytes=4200, priority=33,ip,reg15=0x5,metadata=0xc,nw_src=192.168.1.6 actions=ct(commit,table=42,zone=NXM_NX_REG12[0..15],nat(src=10.74.167.210))
        ct_snat(10.74.167.210);
    
    ct_snat(ip4.src=10.74.167.210)
    ------------------------------
     3. lr_out_delivery (ovn-northd.c:6334): outport == "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373", priority 100, uuid 5b4bf15f
        cookie=0x5b4bf15f, duration=251183.066s, table=43, n_packets=4416, n_bytes=425000, priority=100,reg15=0x5,metadata=0xc actions=resubmit(,64)
        output;
        /* output to "lrp-ef37243a-ac26-4c00-8c84-ebd90d6bb373", type "patch" */
    
    ingress(dp="a28109b8-9d27-4551-a983-8c3bc98cda0c", inport="ef37243a-ac26-4c00-8c84-ebd90d6bb373")
    -------------------------------------------------------------------------------------------------
     0. ls_in_port_sec_l2 (ovn-northd.c:3867): inport == "ef37243a-ac26-4c00-8c84-ebd90d6bb373", priority 50, uuid 3a67f28b
        cookie=0x3a67f28b, duration=251183.065s, table=8, n_packets=4431, n_bytes=425630, priority=50,reg14=0x3,metadata=0x1 actions=resubmit(,9)
        next;
    16. ls_in_l2_lkup (ovn-northd.c:4307): 1, priority 0, uuid 96f935c1
        cookie=0x96f935c1, duration=251183.067s, table=24, n_packets=4415, n_bytes=424958, priority=0,metadata=0x1 actions=set_field:0xfffe->reg15,resubmit(,32)
        outport = "_MC_unknown";
        output;
    
    multicast(dp="a28109b8-9d27-4551-a983-8c3bc98cda0c", mcgroup="_MC_unknown")
    ---------------------------------------------------------------------------
    
        egress(dp="a28109b8-9d27-4551-a983-8c3bc98cda0c", inport="ef37243a-ac26-4c00-8c84-ebd90d6bb373", outport="provnet-53457a6f-fccd-480e-be35-18f4edd71923")
        --------------------------------------------------------------------------------------------------------------------------------------------------------
             9. ls_out_port_sec_l2 (ovn-northd.c:4344): outport == "provnet-53457a6f-fccd-480e-be35-18f4edd71923", priority 50, uuid da903ade
                cookie=0xda903ade, duration=251183.070s, table=49, n_packets=4415, n_bytes=424958, priority=50,reg15=0x1,metadata=0x1 actions=resubmit(,64)
                output;
                /* output to "provnet-53457a6f-fccd-480e-be35-18f4edd71923", type "localnet" */
    
  4. Sample output with --friendly-names option.

    # ovn-trace --friendly-names --ovs neutron-250d6622-eec8-4471-ae89-3eb0302be2e2 --db=$SB 'inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && eth.src == fa:16:3e:bb:7e:52 &&  eth.dst == fa:16:3e:30:ed:9b && ip4.src == 192.168.1.6 && ip4.dst == 10.74.167.222 && ip.ttl == 64 && icmp4.type == 8'
    # icmp,reg14=0x4,vlan_tci=0x0000,dl_src=fa:16:3e:bb:7e:52,dl_dst=fa:16:3e:30:ed:9b,nw_src=192.168.1.6,nw_dst=10.74.167.222,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
    
    ingress(dp="internal1", inport="45b379")
    ----------------------------------------
     0. ls_in_port_sec_l2 (ovn-northd.c:3867): inport == "45b379" && eth.src == {fa:16:3e:bb:7e:52}, priority 50, uuid d1dce7a9
        cookie=0xd1dce7a9, duration=254083.947s, table=8, n_packets=542, n_bytes=66717, priority=50,reg14=0x4,metadata=0xa,dl_src=fa:16:3e:bb:7e:52 actions=resubmit(,9)
        next;
     1. ls_in_port_sec_ip (ovn-northd.c:2849): inport == "45b379" && eth.src == fa:16:3e:bb:7e:52 && ip4.src == {192.168.1.6}, priority 90, uuid 4af885b6
        cookie=0x4af885b6, duration=254083.946s, table=9, n_packets=500, n_bytes=64165, priority=90,ip,reg14=0x4,metadata=0xa,dl_src=fa:16:3e:bb:7e:52,nw_src=192.168.1.6 actions=resubmit(,10)
        next;
     3. ls_in_pre_acl (ovn-northd.c:3150): ip, priority 100, uuid a71014c0
        cookie=0xa71014c0, duration=254089.780s, table=11, n_packets=4, n_bytes=360, priority=100,ipv6,metadata=0xa actions=load:0x1->NXM_NX_XXREG0[96],resubmit(,12)
        cookie=0xa71014c0, duration=254089.780s, table=11, n_packets=548, n_bytes=70155, priority=100,ip,metadata=0xa actions=load:0x1->NXM_NX_XXREG0[96],resubmit(,12)
        reg0[0] = 1;
        next;
     5. ls_in_pre_stateful (ovn-northd.c:3287): reg0[0] == 1, priority 100, uuid 8f3c5a49
        cookie=0x8f3c5a49, duration=254137.045s, table=13, n_packets=548, n_bytes=70155, priority=100,ip,reg0=0x1/0x1,metadata=0xa actions=ct(table=14,zone=NXM_NX_REG13[0..15])
        cookie=0x8f3c5a49, duration=254137.044s, table=13, n_packets=4, n_bytes=360, priority=100,ipv6,reg0=0x1/0x1,metadata=0xa actions=ct(table=14,zone=NXM_NX_REG13[0..15])
        ct_next;
    
    ct_next(ct_state=est|trk /* default (use --ct to customize) */)
    ---------------------------------------------------------------
     6. ls_in_acl (ovn-northd.c:3495): !ct.new && ct.est && !ct.rpl && ct_label.blocked == 0 && (inport == "45b379" && ip4), priority 2002, uuid d525e066
        cookie=0xd525e066, duration=254083.947s, table=14, n_packets=75, n_bytes=7610, priority=2002,ct_state=-new+est-rpl+trk,ct_label=0/0x1,ip,reg14=0x4,metadata=0xa actions=resubmit(,15)
        next;
    16. ls_in_l2_lkup (ovn-northd.c:4261): eth.dst == fa:16:3e:30:ed:9b, priority 50, uuid 35cc93a3
        cookie=0x35cc93a3, duration=254137.046s, table=24, n_packets=399, n_bytes=51793, priority=50,metadata=0xa,dl_dst=fa:16:3e:30:ed:9b actions=set_field:0x2->reg15,resubmit(,32)
        outport = "26aa8f";
        output;
    
    egress(dp="internal1", inport="45b379", outport="26aa8f")
    ---------------------------------------------------------
     1. ls_out_pre_acl (ovn-northd.c:3109): ip && outport == "26aa8f", priority 110, uuid af93b9cd
        cookie=0xaf93b9cd, duration=254089.781s, table=41, n_packets=399, n_bytes=51793, priority=110,ip,reg15=0x2,metadata=0xa actions=resubmit(,42)
        cookie=0xaf93b9cd, duration=254089.781s, table=41, n_packets=0, n_bytes=0, priority=110,ipv6,reg15=0x2,metadata=0xa actions=resubmit(,42)
        next;
     9. ls_out_port_sec_l2 (ovn-northd.c:4344): outport == "26aa8f", priority 50, uuid d52c56d2
        cookie=0xd52c56d2, duration=254137.046s, table=49, n_packets=399, n_bytes=51793, priority=50,reg15=0x2,metadata=0xa actions=resubmit(,64)
        output;
        /* output to "26aa8f", type "patch" */
    
    ingress(dp="router1", inport="lrp-26aa8f")
    ------------------------------------------
     0. lr_in_admission (ovn-northd.c:4890): eth.dst == fa:16:3e:30:ed:9b && inport == "lrp-26aa8f", priority 50, uuid fdcdfbae
        cookie=0xfdcdfbae, duration=254137.045s, table=8, n_packets=399, n_bytes=51793, priority=50,reg14=0x1,metadata=0xc,dl_dst=fa:16:3e:30:ed:9b actions=resubmit(,9)
        next;
     7. lr_in_ip_routing (ovn-northd.c:4472): ip4.dst == 10.74.167.208/28, priority 57, uuid fca6ccef
        cookie=0xfca6ccef, duration=254137.054s, table=15, n_packets=0, n_bytes=0, priority=57,ip,metadata=0xc,nw_dst=10.74.167.208/28 actions=dec_ttl(),move:NXM_OF_IP_DST[]->NXM_NX_XXREG0[96..127],load:0xa4aa7d5->NXM_NX_XXREG0[64..95],set_field:fa:16:3e:71:74:11->eth_src,set_field:0x5->reg15,load:0x1->NXM_NX_REG10[0],resubmit(,16)
        ip.ttl--;
        reg0 = ip4.dst;
        reg1 = 10.74.167.213;
        eth.src = fa:16:3e:71:74:11;
        outport = "lrp-ef3724";
        flags.loopback = 1;
        next;
     8. lr_in_arp_resolve (ovn-northd.c:6199): ip4, priority 0, uuid f6832489
        cookie=0xf6832489, duration=254137.046s, table=16, n_packets=398, n_bytes=51695, priority=0,ip,metadata=0xc actions=push:NXM_NX_REG0[],push:NXM_NX_XXREG0[96..127],pop:NXM_NX_REG0[],set_field:00:00:00:00:00:00->eth_dst,resubmit(,66),pop:NXM_NX_REG0[],resubmit(,17)
        get_arp(outport, reg0);
        /* MAC binding to f4:b5:2f:40:a6:81. */
        next;
     9. lr_in_gw_redirect (ovn-northd.c:6228): outport == "lrp-ef3724", priority 50, uuid e6dc2d72
        cookie=0xe6dc2d72, duration=254137.046s, table=17, n_packets=397, n_bytes=51610, priority=50,reg15=0x5,metadata=0xc actions=set_field:0x6->reg15,resubmit(,18)
        outport = "cr-lrp-ef3724";
        next;
    10. lr_in_arp_request (ovn-northd.c:6306): 1, priority 0, uuid 7ad01353
        cookie=0x7ad01353, duration=254137.047s, table=18, n_packets=4208, n_bytes=453806, priority=0,metadata=0xc actions=resubmit(,32)
        output;
        /* Replacing type "chassisredirect" outport "cr-lrp-ef3724" with distributed port "lrp-ef3724". */
    
    egress(dp="router1", inport="lrp-26aa8f", outport="lrp-ef3724")
    ---------------------------------------------------------------
     0. lr_out_undnat (ovn-northd.c:5575): ip && ip4.src == 192.168.1.6 && outport == "lrp-ef3724" && is_chassis_resident("cr-lrp-ef3724"), priority 100, uuid b2c757eb
        cookie=0xb2c757eb, duration=253992.859s, table=40, n_packets=397, n_bytes=51610, priority=100,ip,reg15=0x5,metadata=0xc,nw_src=192.168.1.6 actions=ct(table=41,zone=NXM_NX_REG11[0..15],nat)
        ct_dnat;
    
    ct_dnat /* assuming no un-dnat entry, so no change */
    -----------------------------------------------------
     1. lr_out_snat (ovn-northd.c:5622): ip && ip4.src == 192.168.1.6 && outport == "lrp-ef3724" && is_chassis_resident("cr-lrp-ef3724"), priority 33, uuid 907892ee
        cookie=0x907892ee, duration=253992.859s, table=41, n_packets=44, n_bytes=4200, priority=33,ip,reg15=0x5,metadata=0xc,nw_src=192.168.1.6 actions=ct(commit,table=42,zone=NXM_NX_REG12[0..15],nat(src=10.74.167.210))
        ct_snat(10.74.167.210);
    
    ct_snat(ip4.src=10.74.167.210)
    ------------------------------
     3. lr_out_delivery (ovn-northd.c:6334): outport == "lrp-ef3724", priority 100, uuid 5b4bf15f
        cookie=0x5b4bf15f, duration=254137.046s, table=43, n_packets=4443, n_bytes=427252, priority=100,reg15=0x5,metadata=0xc actions=resubmit(,64)
        output;
        /* output to "lrp-ef3724", type "patch" */
    
    ingress(dp="External", inport="ef3724")
    ---------------------------------------
     0. ls_in_port_sec_l2 (ovn-northd.c:3867): inport == "ef3724", priority 50, uuid 3a67f28b
        cookie=0x3a67f28b, duration=254137.046s, table=8, n_packets=4458, n_bytes=427882, priority=50,reg14=0x3,metadata=0x1 actions=resubmit(,9)
        next;
    16. ls_in_l2_lkup (ovn-northd.c:4307): 1, priority 0, uuid 96f935c1
        cookie=0x96f935c1, duration=254137.048s, table=24, n_packets=4442, n_bytes=427210, priority=0,metadata=0x1 actions=set_field:0xfffe->reg15,resubmit(,32)
        outport = "_MC_unknown";
        output;
    
    multicast(dp="External", mcgroup="_MC_unknown")
    -----------------------------------------------
    
        egress(dp="External", inport="ef3724", outport="provnet-53457a")
        ----------------------------------------------------------------
             9. ls_out_port_sec_l2 (ovn-northd.c:4344): outport == "provnet-53457a", priority 50, uuid da903ade
                cookie=0xda903ade, duration=254137.051s, table=49, n_packets=4442, n_bytes=427210, priority=50,reg15=0x1,metadata=0x1 actions=resubmit(,64)
                output;
                /* output to "provnet-53457a", type "localnet" */
    
  5. Sample ovn-trace with --minimal output.

    # ovn-trace --minimal --ovs neutron-250d6622-eec8-4471-ae89-3eb0302be2e2 --db=$SB 'inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && eth.src == fa:16:3e:bb:7e:52 &&  eth.dst == fa:16:3e:30:ed:9b && ip4.src == 192.168.1.6 && ip4.dst == 10.74.167.222 && ip.ttl == 64 && icmp4.type == 8'
    # icmp,reg14=0x4,vlan_tci=0x0000,dl_src=fa:16:3e:bb:7e:52,dl_dst=fa:16:3e:30:ed:9b,nw_src=192.168.1.6,nw_dst=10.74.167.222,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
    ct_next(ct_state=est|trk /* default (use --ct to customize) */) {
        ip.ttl--;
        eth.src = fa:16:3e:71:74:11;
        eth.dst = f4:b5:2f:40:a6:81;
        ct_dnat /* assuming no un-dnat entry, so no change */ {
            ct_snat(ip4.src=10.74.167.210) {
                output("provnet-53457a");
            };
        };
    };
    
  6. Sample ovn-trace with --summary output.

    # ovn-trace --summary --ovs neutron-250d6622-eec8-4471-ae89-3eb0302be2e2 --db=$SB 'inport == "45b37972-88ad-4f9f-884d-50120fcebc39" && eth.src == fa:16:3e:bb:7e:52 &&  eth.dst == fa:16:3e:30:ed:9b && ip4.src == 192.168.1.6 && ip4.dst == 10.74.167.222 && ip.ttl == 64 && icmp4.type == 8'
    # icmp,reg14=0x4,vlan_tci=0x0000,dl_src=fa:16:3e:bb:7e:52,dl_dst=fa:16:3e:30:ed:9b,nw_src=192.168.1.6,nw_dst=10.74.167.222,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
    ingress(dp="internal1", inport="45b379") {
        cookie=0xd1dce7a9, duration=254255.326s, table=8, n_packets=542, n_bytes=66717, priority=50,reg14=0x4,metadata=0xa,dl_src=fa:16:3e:bb:7e:52 actions=resubmit(,9)
        next;
        cookie=0x4af885b6, duration=254255.325s, table=9, n_packets=500, n_bytes=64165, priority=90,ip,reg14=0x4,metadata=0xa,dl_src=fa:16:3e:bb:7e:52,nw_src=192.168.1.6 actions=resubmit(,10)
        next;
        cookie=0xa71014c0, duration=254261.160s, table=11, n_packets=4, n_bytes=360, priority=100,ipv6,metadata=0xa actions=load:0x1->NXM_NX_XXREG0[96],resubmit(,12)
        cookie=0xa71014c0, duration=254261.160s, table=11, n_packets=548, n_bytes=70155, priority=100,ip,metadata=0xa actions=load:0x1->NXM_NX_XXREG0[96],resubmit(,12)
        reg0[0] = 1;
        next;
        cookie=0x8f3c5a49, duration=254308.425s, table=13, n_packets=548, n_bytes=70155, priority=100,ip,reg0=0x1/0x1,metadata=0xa actions=ct(table=14,zone=NXM_NX_REG13[0..15])
        cookie=0x8f3c5a49, duration=254308.424s, table=13, n_packets=4, n_bytes=360, priority=100,ipv6,reg0=0x1/0x1,metadata=0xa actions=ct(table=14,zone=NXM_NX_REG13[0..15])
        ct_next;
        ct_next(ct_state=est|trk /* default (use --ct to customize) */) {
            cookie=0xd525e066, duration=254255.327s, table=14, n_packets=75, n_bytes=7610, priority=2002,ct_state=-new+est-rpl+trk,ct_label=0/0x1,ip,reg14=0x4,metadata=0xa actions=resubmit(,15)
            next;
            cookie=0x35cc93a3, duration=254308.425s, table=24, n_packets=399, n_bytes=51793, priority=50,metadata=0xa,dl_dst=fa:16:3e:30:ed:9b actions=set_field:0x2->reg15,resubmit(,32)
            outport = "26aa8f";
            output;
            egress(dp="internal1", inport="45b379", outport="26aa8f") {
                cookie=0xaf93b9cd, duration=254261.160s, table=41, n_packets=399, n_bytes=51793, priority=110,ip,reg15=0x2,metadata=0xa actions=resubmit(,42)
                cookie=0xaf93b9cd, duration=254261.160s, table=41, n_packets=0, n_bytes=0, priority=110,ipv6,reg15=0x2,metadata=0xa actions=resubmit(,42)
                next;
                cookie=0xd52c56d2, duration=254308.425s, table=49, n_packets=399, n_bytes=51793, priority=50,reg15=0x2,metadata=0xa actions=resubmit(,64)
                output;
                /* output to "26aa8f", type "patch" */;
                ingress(dp="router1", inport="lrp-26aa8f") {
                    cookie=0xfdcdfbae, duration=254308.424s, table=8, n_packets=399, n_bytes=51793, priority=50,reg14=0x1,metadata=0xc,dl_dst=fa:16:3e:30:ed:9b actions=resubmit(,9)
                    next;
                    cookie=0xfca6ccef, duration=254308.433s, table=15, n_packets=0, n_bytes=0, priority=57,ip,metadata=0xc,nw_dst=10.74.167.208/28 actions=dec_ttl(),move:NXM_OF_IP_DST[]->NXM_NX_XXREG0[96..127],load:0xa4aa7d5->NXM_NX_XXREG0[64..95],set_field:fa:16:3e:71:74:11->eth_src,set_field:0x5->reg15,load:0x1->NXM_NX_REG10[0],resubmit(,16)
                    ip.ttl--;
                    reg0 = ip4.dst;
                    reg1 = 10.74.167.213;
                    eth.src = fa:16:3e:71:74:11;
                    outport = "lrp-ef3724";
                    flags.loopback = 1;
                    next;
                    cookie=0xf6832489, duration=254308.425s, table=16, n_packets=398, n_bytes=51695, priority=0,ip,metadata=0xc actions=push:NXM_NX_REG0[],push:NXM_NX_XXREG0[96..127],pop:NXM_NX_REG0[],set_field:00:00:00:00:00:00->eth_dst,resubmit(,66),pop:NXM_NX_REG0[],resubmit(,17)
                    get_arp(outport, reg0);
                    /* MAC binding to f4:b5:2f:40:a6:81. */
                    next;
                    cookie=0xe6dc2d72, duration=254308.425s, table=17, n_packets=397, n_bytes=51610, priority=50,reg15=0x5,metadata=0xc actions=set_field:0x6->reg15,resubmit(,18)
                    outport = "cr-lrp-ef3724";
                    next;
                    cookie=0x7ad01353, duration=254308.427s, table=18, n_packets=4211, n_bytes=454148, priority=0,metadata=0xc actions=resubmit(,32)
                    output;
                    /* Replacing type "chassisredirect" outport "cr-lrp-ef3724" with distributed port "lrp-ef3724". */;
                    egress(dp="router1", inport="lrp-26aa8f", outport="lrp-ef3724") {
                        cookie=0xb2c757eb, duration=254164.239s, table=40, n_packets=397, n_bytes=51610, priority=100,ip,reg15=0x5,metadata=0xc,nw_src=192.168.1.6 actions=ct(table=41,zone=NXM_NX_REG11[0..15],nat)
                        ct_dnat;
                        ct_dnat /* assuming no un-dnat entry, so no change */ {
                            cookie=0x907892ee, duration=254164.239s, table=41, n_packets=44, n_bytes=4200, priority=33,ip,reg15=0x5,metadata=0xc,nw_src=192.168.1.6 actions=ct(commit,table=42,zone=NXM_NX_REG12[0..15],nat(src=10.74.167.210))
                            ct_snat(10.74.167.210);
                            ct_snat(ip4.src=10.74.167.210) {
                                cookie=0x5b4bf15f, duration=254308.426s, table=43, n_packets=4446, n_bytes=427516, priority=100,reg15=0x5,metadata=0xc actions=resubmit(,64)
                                output;
                                /* output to "lrp-ef3724", type "patch" */;
                                ingress(dp="External", inport="ef3724") {
                                    cookie=0x3a67f28b, duration=254308.425s, table=8, n_packets=4461, n_bytes=428146, priority=50,reg14=0x3,metadata=0x1 actions=resubmit(,9)
                                    next;
                                    cookie=0x96f935c1, duration=254308.427s, table=24, n_packets=4445, n_bytes=427474, priority=0,metadata=0x1 actions=set_field:0xfffe->reg15,resubmit(,32)
                                    outport = "_MC_unknown";
                                    output;
                                    multicast(dp="External", mcgroup="_MC_unknown") {
                                        egress(dp="External", inport="ef3724", outport="provnet-53457a") {
                                            cookie=0xda903ade, duration=254308.430s, table=49, n_packets=4445, n_bytes=427474, priority=50,reg15=0x1,metadata=0x1 actions=resubmit(,64)
                                            output;
                                            /* output to "provnet-53457a", type "localnet" */;
                                        };
                                    };
                                };
                            };
                        };
                    };
                };
            };
        };
    };
    

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