net/ovs.py: refactor module

Refactor the utils_net.py:
1. Split net_driver/ovs module from utils_net module.

Signed-off-by: Houqi (Nick) Zuo <[email protected]>

virttest/vt_utils/net_driver/ovs.py

@@ -0,0 +1,61 @@
+# Library for the openvswitch related functions.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; specifically version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See LICENSE for more details.
+#
+# Copyright: Red Hat (c) 2024 and Avocado contributors
+# Author: Houqi Zuo <[email protected]>
+from avocado.utils import process
+
+
+def ovs_br_exists(brname):
+    """
+    Check if bridge exists or not.
+
+    :param brname: Name of the bridge.
+    :type brname: String.
+
+    :return: True if found, otherwise, return False.
+    :rtype: Boolean.
+
+    :raise: RuntimeError if executing command fails.
+    """
+    cmd = "ovs-vsctl br-exists %s" % brname
+    cmd_obj = process.run(cmd, shell=True)
+    status = cmd_obj.exit_status
+    if status != 0:
+        return False
+    return True
+
+
+def add_ovs_bridge(brname):
+    """
+    Add a bridge.
+
+    :param brname: Name of the bridge.
+    :type brname: String.
+
+    :raise: RuntimeError if executing command fails.
+    """
+    cmd = "ovs-vsctl --may-exist add-br %s" % brname
+    process.run(cmd, shell=True)
+
+
+def del_ovs_bridge(brname):
+    """
+    Delete a bridge from ovs.
+
+    :param brname: Name of the bridge.
+    :type brname: String.
+
+    :raise: RuntimeError if executing command fails.
+    """
+    cmd = "ovs-vsctl --if-exists del-br %s" % brname
+    process.run(cmd, shell=True)