Description of problem:
Two passt instances of different guests sometimes fail to communicate with using the address of the default gateway through TCP

Version-Release number of selected component (if applicable):
passt-0^20230222.g4ddbcb9-1.el9.x86_64
qemu-kvm-7.2.0-9.el9.x86_64
kernel-5.14.0-281.el9.x86_64
libvirt-9.0.0-6.el9.x86_64
seabios-bin-1.16.1-1.el9.noarch
edk2-ovmf-20221207gitfff6d81270b5-6.el9.noarch

How reproducible:
2/5

Steps to Reproduce:
1.Create two passt instance and boot up the corresponding guest:
 Passt1: $ passt  -f -t 10001 -u 10001 -P passt1.pid
         $ PATH:/usr/libexec
         $ qrap 5 qemu-kvm -m 16059 -smp 6 -blockdev '{"node-name": "file_ovmf_code", "driver": "file", "filename": "/usr/share/OVMF/OVMF_CODE.secboot.fd", "auto-read-only": true, "discard": "unmap"}' -blockdev '{"node-name": "drive_ovmf_code", "driver": "raw", "read-only": true, "file": "file_ovmf_code"}' -blockdev '{"node-name": "file_ovmf_vars", "driver": "file", "filename": "/home/test/avocado-vt-vm1_rhel920-64-virtio-scsi_qcow2_filesystem_VARS.fd", "auto-read-only": true, "discard": "unmap"}' -blockdev '{"node-name": "drive_ovmf_vars", "driver": "raw", "read-only": false, "file": "file_ovmf_vars"}' -machine q35,memory-backend=mem-machine_mem,pflash0=drive_ovmf_code,pflash1=drive_ovmf_vars -device '{"id": "pcie-root-port-0", "driver": "pcie-root-port", "multifunction": true, "bus": "pcie.0", "addr": "0x1", "chassis": 1}' -device '{"id": "pcie-pci-bridge-0", "driver": "pcie-pci-bridge", "addr": "0x0", "bus": "pcie-root-port-0"}' -nodefaults -device '{"driver": "VGA", "bus": "pcie.0", "addr": "0x2"}' -m 62464 -object '{"size": 65498251264, "id": "mem-machine_mem", "qom-type": "memory-backend-ram"}' -smp 28,maxcpus=28,cores=14,threads=1,dies=1,sockets=2 -cpu 'Icelake-Server',ds=on,ss=on,dtes64=on,vmx=on,pdcm=on,hypervisor=on,tsc-adjust=on,avx512ifma=on,sha-ni=on,rdpid=on,fsrm=on,md-clear=on,stibp=on,arch-capabilities=on,xsaves=on,ibpb=on,ibrs=on,amd-stibp=on,amd-ssbd=on,rdctl-no=on,ibrs-all=on,skip-l1dfl-vmentry=on,mds-no=on,pschange-mc-no=on,tsx-ctrl=on,hle=off,rtm=off,mpx=off,intel-pt=off,kvm_pv_unhalt=on  -device '{"id": "pcie-root-port-2", "port": 2, "driver": "pcie-root-port", "addr": "0x1.0x2", "bus": "pcie.0", "chassis": 3}' -device '{"id": "virtio_scsi_pci0", "driver": "virtio-scsi-pci", "bus": "pcie-root-port-2", "addr": "0x0"}' -blockdev '{"node-name": "file_image1", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/test/rhel920-64-virtio-scsi.qcow2", "cache": {"direct": true, "no-flush": false}}' -blockdev '{"node-name": "drive_image1", "driver": "qcow2", "read-only": false, "cache": {"direct": true, "no-flush": false}, "file": "file_image1"}' -device '{"driver": "scsi-hd", "id": "image1", "drive": "drive_image1", "write-cache": "on"}' -device '{"id": "pcie-root-port-3", "port": 3, "driver": "pcie-root-port", "addr": "0x1.0x3", "bus": "pcie.0", "chassis": 4}' -device '{"driver": "virtio-net-pci", "id": "net0", "netdev": "hostnet0", "x-txburst": 16384, "bus": "pcie-root-port-3", "addr": "0x0"}' -netdev socket,fd=5,id=hostnet0 -boot menu=off,order=cdn,once=c,strict=off -vnc :0 -boot menu=off,order=cdn,once=c,strict=off -monitor stdio


  Passt2: $ passt  -f -t 10002 -u 10002 -P passt2.pid
          $ PATH=$PATH:/usr/libexec
          $ qrap 5 qemu-kvm -m 16059 -smp 6 -blockdev '{"node-name": "file_ovmf_code", "driver": "file", "filename": "/usr/share/OVMF/OVMF_CODE.secboot.fd", "auto-read-only": true, "discard": "unmap"}' -blockdev '{"node-name": "drive_ovmf_code", "driver": "raw", "read-only": true, "file": "file_ovmf_code"}' -blockdev '{"node-name": "file_ovmf_vars", "driver": "file", "filename": "/home/test/2.fd", "auto-read-only": true, "discard": "unmap"}' -blockdev '{"node-name": "drive_ovmf_vars", "driver": "raw", "read-only": false, "file": "file_ovmf_vars"}' -machine q35,memory-backend=mem-machine_mem,pflash0=drive_ovmf_code,pflash1=drive_ovmf_vars -device '{"id": "pcie-root-port-0", "driver": "pcie-root-port", "multifunction": true, "bus": "pcie.0", "addr": "0x1", "chassis": 1}' -device '{"id": "pcie-pci-bridge-0", "driver": "pcie-pci-bridge", "addr": "0x0", "bus": "pcie-root-port-0"}' -nodefaults -device '{"driver": "VGA", "bus": "pcie.0", "addr": "0x2"}' -m 62464 -object '{"size": 65498251264, "id": "mem-machine_mem", "qom-type": "memory-backend-ram"}' -smp 28,maxcpus=28,cores=14,threads=1,dies=1,sockets=2 -cpu 'Icelake-Server',ds=on,ss=on,dtes64=on,vmx=on,pdcm=on,hypervisor=on,tsc-adjust=on,avx512ifma=on,sha-ni=on,rdpid=on,fsrm=on,md-clear=on,stibp=on,arch-capabilities=on,xsaves=on,ibpb=on,ibrs=on,amd-stibp=on,amd-ssbd=on,rdctl-no=on,ibrs-all=on,skip-l1dfl-vmentry=on,mds-no=on,pschange-mc-no=on,tsx-ctrl=on,hle=off,rtm=off,mpx=off,intel-pt=off,kvm_pv_unhalt=on  -device '{"id": "pcie-root-port-2", "port": 2, "driver": "pcie-root-port", "addr": "0x1.0x2", "bus": "pcie.0", "chassis": 3}' -device '{"id": "virtio_scsi_pci0", "driver": "virtio-scsi-pci", "bus": "pcie-root-port-2", "addr": "0x0"}' -blockdev '{"node-name": "file_image1", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/test/2.qcow2", "cache": {"direct": true, "no-flush": false}}' -blockdev '{"node-name": "drive_image1", "driver": "qcow2", "read-only": false, "cache": {"direct": true, "no-flush": false}, "file": "file_image1"}' -device '{"driver": "scsi-hd", "id": "image1", "drive": "drive_image1", "write-cache": "on"}' -device '{"id": "pcie-root-port-3", "port": 3, "driver": "pcie-root-port", "addr": "0x1.0x3", "bus": "pcie.0", "chassis": 4}' -device '{"driver": "virtio-net-pci", "id": "net0", "netdev": "hostnet0", "x-txburst": 16384, "bus": "pcie-root-port-3", "addr": "0x0"}' -netdev socket,fd=5,id=hostnet0 -boot menu=off,order=cdn,once=c,strict=off -vnc :1 -boot menu=off,order=cdn,once=c,strict=off -monitor stdio

2.Disable firewall in two guests and host.
# systemctl stop firewalld.service || service iptables stop || iptables -F || nft flush ruleset

3.Two guests communicating through TCP using the default gateway address sometimes fails
On guest 2:
# nc -l 10002

On guest1:
# echo "Hello from guest1" | nc 10.73.213.254 10002
Nact: TIMEOUT

Actual results:
Nact: TIMEOUT

Expected results:
Two guests can communicate with each other via TCP using the address of the default gateway

Additional info:
1. From the QE perspective, it should not a regression bug, since this scenario always test with seabios guest in the past,this issue maybe have always existed. And test passed with seabios guest when used the same host env (Tested 5 times).