Merge "framework: Add reworked framework to repo"

6 files changed, 902 insertions, 0 deletions

diff --git a/src/__init__.py b/src/__init__.py
new file mode 100644
index 00000000..9293b4f8
--- /dev/null
+++ b/src/__init__.py
@@ -0,0 +1,21 @@
+# Copyright 2015 Intel Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""High level package for VSPERF dependencies
+
+No functionality is expected for this package and its purpose is just to
+keep Python package structure intact without extra requirements for
+PYTHONPATH.
+"""
+
diff --git a/src/dpdk/__init__.py b/src/dpdk/__init__.py
new file mode 100644
index 00000000..4be1e215
--- /dev/null
+++ b/src/dpdk/__init__.py
@@ -0,0 +1,21 @@
+# Copyright 2015 Intel Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""A collection of functions for automating the DPDK setup and teardown.
+
+These automation tasks include mounting/unmounting hugepages, inserting
+and removing drivers and binding/unbinding NICs.
+"""
+
+from src.dpdk.dpdk import *
diff --git a/src/dpdk/dpdk.py b/src/dpdk/dpdk.py
new file mode 100644
index 00000000..9b3d1385
--- /dev/null
+++ b/src/dpdk/dpdk.py
@@ -0,0 +1,377 @@
+# Copyright 2015 Intel Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Automation of system configuration for DPDK use.
+
+Parts of this based on ``tools/pci_unbind.py`` script from Intel(R) DPDK.
+"""
+
+from sys import platform as _platform
+
+import os
+import re
+import subprocess
+import logging
+import locale
+
+from tools import tasks
+from conf import settings
+
+_LOGGER = logging.getLogger(__name__)
+RTE_PCI_TOOL = os.path.join(
+    settings.getValue('RTE_SDK'), 'tools', 'dpdk_nic_bind.py')
+
+#
+# system management
+#
+
+
+def init():
+    """Setup system for DPDK.
+    """
+    if not _is_linux():
+        _LOGGER.error('Not running on a compatible Linux version. Exiting...')
+        return
+
+    _mount_hugepages()
+    _insert_modules()
+    _remove_vhost_net()
+    _bind_nics()
+    _copy_dpdk_for_guest()
+
+
+def cleanup():
+    """Setup system for DPDK.
+    """
+    if not _is_linux():
+        _LOGGER.error('Not running on a compatible Linux version. Exiting...')
+        return
+
+    _unbind_nics()
+    _remove_modules()
+    _umount_hugepages()
+    _vhost_user_cleanup()
+
+
+#
+# vhost specific modules management
+#
+
+
+def insert_vhost_modules():
+    """Inserts VHOST related kernel modules
+    """
+    mod_path_prefix = os.path.join(settings.getValue('RTE_SDK'),
+                                   'lib',
+                                   'librte_vhost')
+    _insert_module_group('VHOST_MODULE', mod_path_prefix)
+
+
+def remove_vhost_modules():
+    """Removes all VHOST related kernel modules
+    """
+    _remove_module_group('VHOST_MODULE')
+
+#
+# basic compatibility test
+#
+
+
+def _is_linux():
+    """Check if running on Linux.
+
+    Many of the functions in this file rely on features commonly found
+    only on Linux (i.e. ``/proc`` is not present on FreeBSD). Hence, this
+    check is important to ensure someone doesn't run this on an incompatible
+    OS or distro.
+    """
+    return _platform.startswith('linux') and os.path.isdir('/proc')
+
+#
+# hugepage management
+#
+
+
+def _is_hugepage_available():
+    """Check if hugepages are available on the system.
+    """
+    hugepage_re = re.compile(r'^HugePages_Free:\s+(?P<num_hp>\d+)$')
+
+    # read in meminfo
+    with open('/proc/meminfo') as mem_file:
+        mem_info = mem_file.readlines()
+
+    # first check if module is loaded
+    for line in mem_info:
+        result = hugepage_re.match(line)
+        if not result:
+            continue
+
+        num_huge = result.group('num_hp')
+        if not num_huge:
+            _LOGGER.info('No free hugepages.')
+        else:
+            _LOGGER.info('Found \'%s\' free hugepage(s).', num_huge)
+        return True
+
+    return False
+
+
+def _is_hugepage_mounted():
+    """Check if hugepages are mounted.
+    """
+    output = subprocess.check_output(['mount'], shell=True)
+    my_encoding = locale.getdefaultlocale()[1]
+    for line in output.decode(my_encoding).split('\n'):
+        if 'hugetlbfs' in line:
+            return True
+
+    return False
+
+
+def _mount_hugepages():
+    """Ensure hugepages are mounted.
+    """
+    if not _is_hugepage_available():
+        return
+
+    if _is_hugepage_mounted():
+        return
+
+    if not os.path.exists(settings.getValue('HUGEPAGE_DIR')):
+        os.makedirs(settings.getValue('HUGEPAGE_DIR'))
+    try:
+        tasks.run_task(['sudo', 'mount', '-t', 'hugetlbfs', 'nodev',
+                        settings.getValue('HUGEPAGE_DIR')],
+                       _LOGGER, 'Mounting hugepages...', True)
+    except subprocess.CalledProcessError:
+        _LOGGER.error('Unable to mount hugepages.')
+
+
+def _umount_hugepages():
+    """Ensure hugepages are unmounted.
+    """
+    if not _is_hugepage_mounted():
+        return
+
+    try:
+        tasks.run_task(['sudo', 'umount', settings.getValue('HUGEPAGE_DIR')],
+                       _LOGGER, 'Unmounting hugepages...', True)
+    except subprocess.CalledProcessError:
+        _LOGGER.error('Unable to umount hugepages.')
+
+#
+# module management
+#
+
+
+def _is_module_inserted(module):
+    """Check if a module is inserted on system.
+    """
+    with open('/proc/modules') as mod_file:
+        loaded_mods = mod_file.readlines()
+
+    # first check if module is loaded
+    for line in loaded_mods:
+        if line.startswith(module):
+            return True
+    return False
+
+
+def _insert_modules():
+    """Ensure required modules are inserted on system.
+    """
+    for module in settings.getValue('SYS_MODULES'):
+        if _is_module_inserted(module):
+            continue
+
+        try:
+            tasks.run_task(['sudo', 'modprobe', module], _LOGGER,
+                           'Inserting module \'%s\'...' % module, True)
+        except subprocess.CalledProcessError:
+            _LOGGER.error('Unable to insert module \'%s\'.', module)
+            raise  # fail catastrophically
+
+    mod_path_prefix = settings.getValue('OVS_DIR')
+    _insert_module_group('OVS_MODULES', mod_path_prefix)
+    mod_path_prefix = os.path.join(settings.getValue('RTE_SDK'),
+                                   settings.getValue('RTE_TARGET'))
+    _insert_module_group('DPDK_MODULES', mod_path_prefix)
+
+
+def _insert_module_group(module_group, group_path_prefix):
+    """Ensure all modules in a group are inserted into the system.
+
+    :param module_group: A name of configuration item containing a list
+    of module names
+    """
+    for module in settings.getValue(module_group):
+        # first check if module is loaded
+        if _is_module_inserted(module[1]):
+            continue
+
+        try:
+            mod_path = os.path.join(group_path_prefix, module[0],
+                                    '%s.ko' % module[1])
+            tasks.run_task(['sudo', 'insmod', mod_path], _LOGGER,
+                           'Inserting module \'%s\'...' % module[1], True)
+        except subprocess.CalledProcessError:
+            _LOGGER.error('Unable to insert module \'%s\'.', module[1])
+            raise  # fail catastrophically
+
+
+def _remove_modules():
+    """Ensure required modules are removed from system.
+    """
+    _remove_module_group('OVS_MODULES')
+    _remove_module_group('DPDK_MODULES')
+
+    for module in settings.getValue('SYS_MODULES'):
+        # first check if module is loaded
+        if not _is_module_inserted(module):
+            continue
+
+        try:
+            tasks.run_task(['sudo', 'rmmod', module], _LOGGER,
+                           'Removing module \'%s\'...' % module, True)
+        except subprocess.CalledProcessError:
+            _LOGGER.error('Unable to remove module \'%s\'.', module)
+            continue
+
+
+def _remove_module_group(module_group):
+    """Ensure all modules in a group are removed from the system.
+
+    :param module_group: A name of configuration item containing a list
+    of module names
+    """
+    for module in settings.getValue(module_group):
+        # first check if module is loaded
+        if not _is_module_inserted(module[1]):
+            continue
+
+        try:
+            tasks.run_task(['sudo', 'rmmod', module[1]], _LOGGER,
+                           'Removing module \'%s\'...' % module[1], True)
+        except subprocess.CalledProcessError:
+            _LOGGER.error('Unable to remove module \'%s\'.', module[1])
+            continue
+
+
+#
+# 'vhost-net' module management
+#
+
+def _remove_vhost_net():
+    """Remove vhost-net driver and file.
+    """
+    if _is_module_inserted('vhost_net'):
+        try:
+            tasks.run_task(['sudo', 'rmmod', 'vhost_net'], _LOGGER,
+                           'Removing \'/dev/vhost-net\' directory...', True)
+        except subprocess.CalledProcessError:
+            _LOGGER.error('Unable to remove module \'vhost_net\'.')
+
+    try:
+        tasks.run_task(['sudo', 'rm', '-f', '/dev/vhost-net'], _LOGGER,
+                       'Removing \'/dev/vhost-net\' directory...', True)
+    except subprocess.CalledProcessError:
+        _LOGGER.error('Unable to remove directory \'/dev/vhost-net\'.')
+
+#
+# NIC management
+#
+
+
+def _bind_nics():
+    """Bind NICs using the Intel DPDK ``pci_unbind.py`` tool.
+    """
+    try:
+        tasks.run_task(['sudo', RTE_PCI_TOOL, '--bind', 'igb_uio'] +
+                       settings.getValue('WHITELIST_NICS'), _LOGGER,
+                       'Binding NICs %s...' %
+                       settings.getValue('WHITELIST_NICS'),
+                       True)
+    except subprocess.CalledProcessError:
+        _LOGGER.error('Unable to bind NICs %s',
+                      str(settings.getValue('WHITELIST_NICS')))
+
+
+def _unbind_nics():
+    """Unbind NICs using the Intel DPDK ``pci_unbind.py`` tool.
+    """
+    try:
+        tasks.run_task(['sudo', RTE_PCI_TOOL, '--unbind'] +
+                       settings.getValue('WHITELIST_NICS'), _LOGGER,
+                       'Unbinding NICs %s...' %
+                       str(settings.getValue('WHITELIST_NICS')),
+                       True)
+    except subprocess.CalledProcessError:
+        _LOGGER.error('Unable to unbind NICs %s',
+                      str(settings.getValue('WHITELIST_NICS')))
+
+
+def _copy_dpdk_for_guest():
+    """Copy dpdk code to GUEST_SHARE_DIR for use by guests.
+    """
+    guest_share_dir = os.path.join(
+        settings.getValue('GUEST_SHARE_DIR'), 'DPDK')
+
+    if not os.path.exists(guest_share_dir):
+        os.makedirs(guest_share_dir)
+
+    try:
+        tasks.run_task(['rsync', '-a', '-r', '-l', r'--exclude="\.git"',
+                        os.path.join(settings.getValue('RTE_SDK'), ''),
+                        guest_share_dir],
+                       _LOGGER,
+                       'Copying DPDK to shared directory...',
+                       True)
+    except subprocess.CalledProcessError:
+        _LOGGER.error('Unable to copy DPDK to shared directory')
+
+
+#
+# Vhost-user cleanup
+#
+
+def _vhost_user_cleanup():
+    """Remove files created by vhost-user tests.
+    """
+    for sock in settings.getValue('VHOST_USER_SOCKS'):
+        if os.path.exists(sock):
+            try:
+                tasks.run_task(['sudo', 'rm', sock],
+                               _LOGGER,
+                               'Deleting vhost-user socket \'%s\'...' %
+                               sock,
+                               True)
+
+            except subprocess.CalledProcessError:
+                _LOGGER.error('Unable to delete vhost-user socket \'%s\'.',
+                              sock)
+                continue
+
+
+class Dpdk(object):
+    """A context manager for the system init/cleanup.
+    """
+    def __enter__(self):
+        _LOGGER.info('Setting up DPDK')
+        init()
+        return self
+
+    def __exit__(self, type_, value, traceback):
+        _LOGGER.info('Cleaning up DPDK')
+        cleanup()
diff --git a/src/ovs/__init__.py b/src/ovs/__init__.py
new file mode 100644
index 00000000..1a31ea2e
--- /dev/null
+++ b/src/ovs/__init__.py
@@ -0,0 +1,25 @@
+# Copyright 2015 Intel Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+A package for controlling Open vSwitch
+
+This package is intended to stay gneneric enough to support using any data
+path of OVS (linux kernel, DPDK userspace, etc.) by different parameterization
+and external setup of vswitchd-external process, kernel modules etc.
+
+"""
+
+from src.ovs.daemon import *
+from src.ovs.ofctl import *
diff --git a/src/ovs/daemon.py b/src/ovs/daemon.py
new file mode 100644
index 00000000..ee3446d5
--- /dev/null
+++ b/src/ovs/daemon.py
@@ -0,0 +1,142 @@
+# Copyright 2015 Intel Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Class wrapper for controlling an OVS instance.
+
+Wraps a pair of ``ovs-vswitchd`` and ``ovsdb-server`` processes.
+"""
+
+import os
+import logging
+import pexpect
+
+from conf import settings
+from tools import tasks
+
+_OVS_VSWITCHD_BIN = os.path.join(
+    settings.getValue('OVS_DIR'), 'vswitchd', 'ovs-vswitchd')
+_OVSDB_TOOL_BIN = os.path.join(
+    settings.getValue('OVS_DIR'), 'ovsdb', 'ovsdb-tool')
+_OVSDB_SERVER_BIN = os.path.join(
+    settings.getValue('OVS_DIR'), 'ovsdb', 'ovsdb-server')
+
+_OVS_VAR_DIR = '/usr/local/var/run/openvswitch/'
+_OVS_ETC_DIR = '/usr/local/etc/openvswitch/'
+
+_LOG_FILE_VSWITCHD = os.path.join(
+    settings.getValue('LOG_DIR'), settings.getValue('LOG_FILE_VSWITCHD'))
+
+class VSwitchd(tasks.Process):
+    """Class wrapper for controlling an OVS instance.
+
+    Wraps a pair of ``ovs-vswitchd`` and ``ovsdb-server`` processes.
+    """
+    _ovsdb_pid = None
+    _logfile = _LOG_FILE_VSWITCHD
+
+
+    _expect = r'EAL: Master l*core \d+ is ready'
+    _proc_name = 'ovs-vswitchd'
+
+    def __init__(self, timeout=30, vswitchd_args=None):
+        """Initialise the wrapper with a specific start timeout and extra
+        parameters.
+
+        :param timeout: Timeout to wait for application to start.
+        :param vswitchd_args: Command line parameters for vswitchd.
+
+        :returns: None
+        """
+        self._logger = logging.getLogger(__name__)
+        self._timeout = timeout
+        vswitchd_args = vswitchd_args or []
+
+        self._cmd = ['sudo', '-E', _OVS_VSWITCHD_BIN] + vswitchd_args
+
+    # startup/shutdown
+
+    def start(self):
+        """ Start ``ovsdb-server`` and ``ovs-vswitchd`` instance.
+
+        :returns: None
+        :raises: pexpect.EOF, pexpect.TIMEOUT
+        """
+        self._reset_ovsdb()
+        self._start_ovsdb()  # this has to be started first
+
+        try:
+            super(VSwitchd, self).start()
+            self.relinquish()
+        except (pexpect.EOF, pexpect.TIMEOUT) as exc:
+            self._kill_ovsdb()
+            raise exc
+
+    def kill(self):
+        """Kill ``ovs-vswitchd`` instance if it is alive.
+
+        :returns: None
+        """
+        self._logger.info('Killing ovs-vswitchd...')
+
+        self._kill_ovsdb()
+
+        super(VSwitchd, self).kill()
+
+    # helper functions
+
+    def _reset_ovsdb(self):
+        """Reset system for 'ovsdb'.
+
+        :returns: None
+        """
+        self._logger.info('Resetting system after last run...')
+
+        tasks.run_task(['sudo', 'rm', '-rf', _OVS_VAR_DIR], self._logger)
+        tasks.run_task(['sudo', 'mkdir', '-p', _OVS_VAR_DIR], self._logger)
+        tasks.run_task(['sudo', 'rm', '-rf', _OVS_ETC_DIR], self._logger)
+        tasks.run_task(['sudo', 'mkdir', '-p', _OVS_ETC_DIR], self._logger)
+
+        tasks.run_task(['sudo', 'rm', '-f',
+                        os.path.join(_OVS_ETC_DIR, 'conf.db')],
+                       self._logger)
+
+        self._logger.info('System reset after last run.')
+
+    def _start_ovsdb(self):
+        """Start ``ovsdb-server`` instance.
+
+        :returns: None
+        """
+        tasks.run_task(['sudo', _OVSDB_TOOL_BIN, 'create',
+                        os.path.join(_OVS_ETC_DIR, 'conf.db'),
+                        os.path.join(settings.getValue('OVS_DIR'), 'vswitchd',
+                                     'vswitch.ovsschema')],
+                       self._logger,
+                       'Creating ovsdb configuration database...')
+
+        self._ovsdb_pid = tasks.run_background_task(
+            ['sudo', _OVSDB_SERVER_BIN,
+             '--remote=punix:%s' % os.path.join(_OVS_VAR_DIR, 'db.sock'),
+             '--remote=db:Open_vSwitch,Open_vSwitch,manager_options'],
+            self._logger,
+            'Starting ovsdb-server...')
+
+    def _kill_ovsdb(self):
+        """Kill ``ovsdb-server`` instance.
+
+        :returns: None
+        """
+        if self._ovsdb_pid:
+            tasks.run_task(['sudo', 'kill', '-2', str(self._ovsdb_pid)],
+                           self._logger, 'Killing ovsdb-server...')
diff --git a/src/ovs/ofctl.py b/src/ovs/ofctl.py
new file mode 100644
index 00000000..c6aaddc9
--- /dev/null
+++ b/src/ovs/ofctl.py
@@ -0,0 +1,316 @@
+# Copyright 2015 Intel Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Wrapper for an OVS bridge for convenient use of ``ovs-vsctl`` and
+``ovs-ofctl`` on it.
+
+Much of this code is based on ``ovs-lib.py`` from Open Stack:
+
+https://github.com/openstack/neutron/blob/6eac1dc99124ca024d6a69b3abfa3bc69c735667/neutron/agent/linux/ovs_lib.py
+"""
+
+import os
+import logging
+import string
+
+from tools import tasks
+from conf import settings
+
+_OVS_VSCTL_BIN = os.path.join(settings.getValue('OVS_DIR'), 'utilities',
+                              'ovs-vsctl')
+_OVS_OFCTL_BIN = os.path.join(settings.getValue('OVS_DIR'), 'utilities',
+                              'ovs-ofctl')
+
+class OFBase(object):
+    """Add/remove/show datapaths using ``ovs-ofctl``.
+    """
+    def __init__(self, timeout=10):
+        """Initialise logger.
+
+        :param timeout: Timeout to be used for each command
+
+        :returns: None
+        """
+        self.logger = logging.getLogger(__name__)
+        self.timeout = timeout
+
+    # helpers
+
+    def run_vsctl(self, args, check_error=False):
+        """Run ``ovs-vsctl`` with supplied arguments.
+
+        :param args: Arguments to pass to ``ovs-vsctl``
+        :param check_error: Throw exception on error
+
+        :return: None
+        """
+        cmd = ['sudo', _OVS_VSCTL_BIN, '--timeout', str(self.timeout)] + args
+        return tasks.run_task(
+            cmd, self.logger, 'Running ovs-vsctl...', check_error)
+
+    # datapath management
+
+    def add_br(self, br_name='br0'):
+        """Add datapath.
+
+        :param br_name: Name of bridge
+
+        :return: Instance of :class OFBridge:
+        """
+        self.logger.debug('add bridge')
+        self.run_vsctl(['add-br', br_name])
+
+        return OFBridge(br_name, self.timeout)
+
+    def del_br(self, br_name='br0'):
+        """Delete datapath.
+
+        :param br_name: Name of bridge
+
+        :return: None
+        """
+        self.logger.debug('delete bridge')
+        self.run_vsctl(['del-br', br_name])
+
+
+class OFBridge(OFBase):
+    """Control a bridge instance using ``ovs-vsctl`` and ``ovs-ofctl``.
+    """
+    def __init__(self, br_name='br0', timeout=10):
+        """Initialise bridge.
+
+        :param br_name: Bridge name
+        :param timeout: Timeout to be used for each command
+
+        :returns: None
+        """
+        super(OFBridge, self).__init__(timeout)
+        self.br_name = br_name
+        self._ports = {}
+
+    # context manager
+
+    def __enter__(self):
+        """Create datapath
+
+        :returns: self
+        """
+        return self
+
+    def __exit__(self, type_, value, traceback):
+        """Remove datapath.
+        """
+        if not traceback:
+            self.destroy()
+
+    # helpers
+
+    def run_ofctl(self, args, check_error=False):
+        """Run ``ovs-ofctl`` with supplied arguments.
+
+        :param args: Arguments to pass to ``ovs-ofctl``
+        :param check_error: Throw exception on error
+
+        :return: None
+        """
+        cmd = ['sudo', _OVS_OFCTL_BIN, '--timeout', str(self.timeout)] + args
+        return tasks.run_task(
+            cmd, self.logger, 'Running ovs-ofctl...', check_error)
+
+    def create(self):
+        """Create bridge.
+        """
+        self.logger.debug('create bridge')
+        self.add_br(self.br_name)
+
+    def destroy(self):
+        """Destroy bridge.
+        """
+        self.logger.debug('destroy bridge')
+        self.del_br(self.br_name)
+
+    def reset(self):
+        """Reset bridge.
+        """
+        self.logger.debug('reset bridge')
+        self.destroy()
+        self.create()
+
+    # port management
+
+    def add_port(self, port_name, params):
+        """Add port to bridge.
+
+        :param port_name: Name of port
+        :param params: Additional list of parameters to add-port
+
+        :return: OpenFlow port number for the port
+        """
+        self.logger.debug('add port')
+        self.run_vsctl(['add-port', self.br_name, port_name]+params)
+
+        # This is how port number allocation works currently
+        # This possibly will not work correctly if there are port deletions
+        # in between
+        of_port = len(self._ports) + 1
+        self._ports[port_name] = (of_port, params)
+        return of_port
+
+    def del_port(self, port_name):
+        """Remove port from bridge.
+
+        :param port_name: Name of port
+
+        :return: None
+        """
+        self.logger.debug('delete port')
+        self.run_vsctl(['del-port', self.br_name, port_name])
+        self._ports.pop(port_name)
+
+    def set_db_attribute(self, table_name, record, column, value):
+        """Set database attribute.
+
+        :param table_name: Name of table
+        :param record: Name of record
+        :param column: Name of column
+        :param value: Value to set
+
+        :return: None
+        """
+        self.logger.debug('set attribute')
+        self.run_vsctl(['set', table_name, record, '%s=%s' % (column, value)])
+
+    def get_ports(self):
+        """Get the ports of this bridge
+
+        Structure of the returned ports dictionary is
+        'portname': (openflow_port_number, extra_parameters)
+
+        Example:
+        ports = {
+            'dpdkport0':
+                (1, ['--', 'set', 'Interface', 'dpdkport0', 'type=dpdk']),
+            'dpdkvhostport0':
+                (2, ['--', 'set', 'Interface', 'dpdkvhostport0',
+                     'type=dpdkvhost'])
+        }
+
+        :return: Dictionary of ports
+        """
+        return self._ports
+
+    def clear_db_attribute(self, table_name, record, column):
+        """Clear database attribute.
+
+        :param table_name: Name of table
+        :param record: Name of record
+        :param column: Name of column
+
+        :return: None
+        """
+        self.logger.debug('clear attribute')
+        self.run_vsctl(['clear', table_name, record, column])
+
+    # flow mangement
+
+    def add_flow(self, flow):
+        """Add flow to bridge.
+
+        :param flow: Flow description as a dictionary
+        For flow dictionary structure, see function flow_key
+
+        :return: None
+        """
+        if not flow.get('actions'):
+            self.logger.error('add flow requires actions')
+            return
+
+        self.logger.debug('add flow')
+        _flow_key = flow_key(flow)
+        self.logger.debug('key : %s', _flow_key)
+        self.run_ofctl(['add-flow', self.br_name, _flow_key])
+
+    def del_flow(self, flow):
+        """Delete flow from bridge.
+
+        :param flow: Flow description as a dictionary
+        For flow dictionary structure, see function flow_key
+        flow=None will delete all flows
+
+        :return: None
+        """
+        self.logger.debug('delete flow')
+        _flow_key = flow_key(flow)
+        self.logger.debug('key : %s', _flow_key)
+        self.run_ofctl(['del-flows', self.br_name, _flow_key])
+
+    def del_flows(self):
+        """Delete all flows from bridge.
+        """
+        self.logger.debug('delete flows')
+        self.run_ofctl(['del-flows', self.br_name])
+
+    def dump_flows(self):
+        """Dump all flows from bridge.
+        """
+        self.logger.debug('dump flows')
+        self.run_ofctl(['dump-flows', self.br_name])
+
+#
+# helper functions
+#
+
+def flow_key(flow):
+    """Model a flow key string for ``ovs-ofctl``.
+
+    Syntax taken from ``ovs-ofctl`` manpages:
+        http://openvswitch.org/cgi-bin/ovsman.cgi?page=utilities%2Fovs-ofctl.8
+
+    Example flow dictionary:
+    flow = {
+        'in_port': '1',
+        'idle_timeout': '0',
+        'actions': ['output:3']
+    }
+
+    :param flow: Flow description as a dictionary
+
+    :return: String
+    :rtype: str
+    """
+    _flow_add_key = string.Template('${fields},action=${actions}')
+    _flow_del_key = string.Template('${fields}')
+
+    field_params = []
+
+    user_params = (x for x in list(flow.items()) if x[0] != 'actions')
+    for (key, default) in user_params:
+        field_params.append('%(field)s=%(value)s' %
+                            {'field': key, 'value': default})
+
+    field_params = ','.join(field_params)
+
+    _flow_key_param = {
+        'fields': field_params,
+    }
+
+    # no actions == delete key
+    if 'actions' in flow:
+        _flow_key_param['actions'] = ','.join(flow['actions'])
+
+        flow_str = _flow_add_key.substitute(_flow_key_param)
+    else:
+        flow_str = _flow_del_key.substitute(_flow_key_param)
+
+    return flow_str