【u2o】Underlay network in custom vpc can't reroute to physical gw when set u2o.

[xujunjie-cover]

Bug Report

Expected Behavior

• only connects the Underlay and Overlay subnets within Kube-OVN
• and other traffic accessing the Internet will still be forwarded through the physical gateway

Actual Behavior

drop

Steps to Reproduce the Problem

1. create vlan subnet with "U2O=true" in custom vpc.

trace:
ingress(dp="vpc1", inport="vpc1-under30")

0. lr_in_admission (northd.c:11885): eth.dst == 00:00:00:0d:48:5e && inport == "vpc1-under30", priority 50, uuid b307c20b
   xreg0[0..47] = 00:00:00:0d:48:5e;
   next;
1. lr_in_lookup_neighbor (northd.c:12062): 1, priority 0, uuid b23ff5d7
   reg9[2] = 1;
   next;
2. lr_in_learn_neighbor (northd.c:12071): reg9[2] == 1, priority 100, uuid d6143ffa
   next;
3. lr_in_ip_routing_pre (northd.c:12299): 1, priority 0, uuid 29e8b11f
   reg7 = 0;
   next;
4. lr_in_ip_routing (northd.c:12376): 1, priority 0, uuid 0214cc43
   drop;

• set +x

in vpc can't hit any flow in table 13 lr_in_ip_routing, after add a static route like " kubectl ko nbctl --policy src-ip lr-route-add vpc1 192.168.30.0/24 192.168.30.1"

ingress(dp="vpc1", inport="vpc1-under30")

0. lr_in_admission (northd.c:11885): eth.dst == 00:00:00:0d:48:5e && inport == "vpc1-under30", priority 50, uuid b307c20b
   xreg0[0..47] = 00:00:00:0d:48:5e;
   next;
1. lr_in_lookup_neighbor (northd.c:12062): 1, priority 0, uuid b23ff5d7
   reg9[2] = 1;
   next;
2. lr_in_learn_neighbor (northd.c:12071): reg9[2] == 1, priority 100, uuid d6143ffa
   next;
3. lr_in_ip_routing_pre (northd.c:12299): 1, priority 0, uuid 29e8b11f
   reg7 = 0;
   next;
4. lr_in_ip_routing (northd.c:10580): ip4.src == 192.168.30.0/24, priority 1, uuid 28cc7a36
   ip.ttl--;
   reg8[0..15] = 0;
   reg0 = 192.168.30.1;
   reg1 = 192.168.30.5;
   eth.src = 00:00:00:0d:48:5e;
   outport = "vpc1-under30";
   flags.loopback = 1;
   next;
5. lr_in_ip_routing_ecmp (northd.c:12377): reg8[0..15] == 0, priority 150, uuid c8a55107
   next;
6. lr_in_policy (northd.c:9718): ip4.src == 192.168.30.0/24, priority 29000, uuid 9e297e76
   reg0 = 192.168.30.1;
   reg1 = 192.168.30.5;
   eth.src = 00:00:00:0d:48:5e;
   outport = "vpc1-under30";
   flags.loopback = 1;
   reg8[0..15] = 0;
   next;
7. lr_in_policy_ecmp (northd.c:12546): reg8[0..15] == 0, priority 150, uuid 63b4debd
   next;
8. lr_in_arp_resolve (northd.c:12581): ip4, priority 1, uuid 726616ab
   get_arp(outport, reg0);
   /* No MAC binding. */
   next;
9. lr_in_arp_request (northd.c:13262): eth.dst == 00:00:00:00:00:00 && ip4, priority 100, uuid f7024caa
   arp { eth.dst = ff:ff:ff:ff:ff:ff; arp.spa = reg1; arp.tpa = reg0; arp.op = 1; output; };

Add static route for vlan subnet with "u2o == true" is necessary ?

[xujunjie-cover]

default vpc has dst-ip 0.0.0.0/0 gw join logical gw. so subnets in default_vpc don't have same issue.

[zhangzujian]

Please provide Kube-OVN version.

[xujunjie-cover]

Please provide Kube-OVN version.

Kube-OVN:
Version: v1.13.0
Build: 2023-11-18_00:35:09
Commit: git-14f136fe
Go Version: go1.21.3
Arch: amd64

commit 14f136f
merged 7 hours ago