net/macvtap.py: refactor module

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

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

virttest/vt_utils/net_driver/macvtap.py

@@ -0,0 +1,126 @@
+# Library for the macvtap address 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]>
+import os
+
+from avocado.utils import process
+
+from virttest import arch, utils_misc
+from virttest.vt_utils.net import interface as iface
+
+
+def create_macvtap(iface=None, tapname=None, mode="vepa", mac_addr=None):
+    """
+    Create a Macvtap device.
+
+    :param iface: The physical interface.
+    :type iface: String.
+    :param tapname: The macvtap name.
+    :type tapname: String.
+    :param mode:  The macvtap type mode (vepa, bridge, private)
+    :type mode: String.
+    :param mac_addr: The macvtap mac address.
+    :type mac_addr: String.
+
+    :raise: A RuntimeError may be raised if running command fails.
+    """
+    if not iface:
+        iface = get_macvtap_base_iface(iface)
+    if not tapname:
+        tapname = "macvtap" + utils_misc.generate_random_id()
+    cmd = "ip link add link %s name %s type %s" % (iface, tapname, mode)
+    process.run(cmd, shell=True)
+    if mac_addr:
+        cmd = "ip link set %s address %s up" % (tapname, mac_addr)
+        process.run(cmd, shell=True)
+
+
+def show_macvtap(tapname):
+    """
+    Show the macvtap details.
+
+    :param tapname: The macvtap name.
+    :type tapname: String.
+
+    :return: The macvtap details.
+    :rtype: String.
+    """
+    cmd = "ip link show %s" % tapname
+    cmd_obj = process.run(cmd, shell=True)
+    return cmd_obj.stdout_text.strip()
+
+
+def delete_macvtap(tapname):
+    """
+    Delete the macvtap.
+
+    :param tapname: The macvtap name.
+    :type tapname: String.
+    """
+    cmd = "ip link delete %s" % tapname
+    process.run(cmd, shell=True)
+
+
+def get_macvtap_base_iface(base_interface=None):
+    """
+    Get physical interface to create macvtap, if you assigned base interface
+    is valid(not belong to any bridge and is up), will use it; else use the
+    first physical interface,  which is not a brport and up.
+    """
+    tap_base_device = None
+
+    (dev_int, _) = iface.get_sorted_net_if()
+
+    if base_interface and base_interface in dev_int:
+        if (not iface.net_if_is_brport(base_interface)) and (
+            iface.is_iface_flag_same(base_interface, arch.IFF_UP)
+        ):
+            tap_base_device = base_interface
+
+    if not tap_base_device:
+        for interface in dev_int:
+            if iface.net_if_is_brport(interface):
+                continue
+            if iface.is_iface_flag_same(interface, arch.IFF_UP):
+                tap_base_device = interface
+                break
+
+    return tap_base_device
+
+
+def open_macvtap(macvtap, queues=1):
+    """
+    Open a macvtap device and returns its file descriptors which are used by
+    fds=<fd1:fd2:..> parameter of qemu.
+
+    For single queue, only returns one file descriptor, it's used by
+    fd=<fd> legacy parameter of qemu.
+
+    If you not have a switch support vepa in you env, run this type case you
+    need at least two nic on you host [just workaround].
+
+    :param macvtap:  The macvtap name.
+    :type macvtap: String.
+    :param queues: Queue number.
+    :type queues: Integer.
+
+    :return: The file descriptors which are used
+             by fds=<fd1:fd2:..> parameter of qemu.
+    :rtype: String.
+    """
+    tapfds = []
+    macvtap = "/dev/%s" % macvtap
+    for queue in range(int(queues)):
+        tapfds.append(str(os.open(macvtap, os.O_RDWR)))
+    return ":".join(tapfds)