From cf5affcff1f57124d6d2fa11a20f995a5c187226 Mon Sep 17 00:00:00 2001
From: Gunjan Vyas <vyasgun20@gmail.com>
Date: Tue, 21 Jan 2025 12:31:44 +0530
Subject: [PATCH] gvforwarder as a systemd service

- Create a tap device using nmcli with a hardcoded mac address
- Start gvforwarder systemd service which will use this device

Signed-off-by: vyasgun <vyasgun20@gmail.com>
---
 createdisk.sh | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/createdisk.sh b/createdisk.sh
index 054e516f..be0710df 100755
--- a/createdisk.sh
+++ b/createdisk.sh
@@ -97,12 +97,38 @@ if podman manifest inspect quay.io/crcont/routes-controller:${OPENSHIFT_VERSION}
     image_tag=${OPENSHIFT_VERSION}
 fi
 
+# create the tap device interface with specified mac address
+# this mac address is used to allocate a specific IP to the VM
+# when tap device is in use.
+${SSH} core@${VM_IP} 'sudo bash -x -s' <<EOF
+  nmcli connection add type tun ifname tap0 con-name tap0 mode tap autoconnect yes 802-3-ethernet.cloned-mac-address 5A:94:EF:E4:0C:EE
+EOF
+
+
 # Add gvisor-tap-vsock service
 ${SSH} core@${VM_IP} 'sudo bash -x -s' <<EOF
-  podman create --name=gvisor-tap-vsock --privileged --net=host -v /etc/resolv.conf:/etc/resolv.conf -it quay.io/crcont/gvisor-tap-vsock:latest
-  podman generate systemd --restart-policy=no gvisor-tap-vsock > /etc/systemd/system/gvisor-tap-vsock.service
+  podman create --name=gvisor-tap-vsock quay.io/crcont/gvisor-tap-vsock:latest
+  podman cp gvisor-tap-vsock:/vm /usr/local/bin/gvforwarder
+  podman rm gvisor-tap-vsock
+  tee /etc/systemd/system/gv-user-network@.service <<TEE
+[Unit]
+Description=gvisor-tap-vsock Network Traffic Forwarder
+After=NetworkManager.service
+BindsTo=sys-devices-virtual-net-%i.device
+After=sys-devices-virtual-net-%i.device
+
+[Service]
+Environment=GV_VSOCK_PORT="1024"
+EnvironmentFile=-/etc/sysconfig/gv-user-network
+ExecStart=/usr/local/bin/gvforwarder -preexisting -iface %i -url vsock://2:\\\${GV_VSOCK_PORT}/connect
+
+[Install]
+WantedBy=multi-user.target
+
+TEE
   systemctl daemon-reload
-  systemctl enable gvisor-tap-vsock.service
+  systemctl enable gv-user-network@tap0.service
+
 EOF
 
 # Add dummy crio-wipe service to instance