236 lines
8.7 KiB
Python
236 lines
8.7 KiB
Python
# Copyright 2016 OVH SAS
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import re
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from neutron_lib import exceptions
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from neutron._i18n import _
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from neutron.agent.linux import ip_lib
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INGRESS_QDISC_ID = "ffff:"
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MAX_MTU_VALUE = 65535
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SI_BASE = 1000
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IEC_BASE = 1024
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LATENCY_UNIT = "ms"
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BW_LIMIT_UNIT = "kbit" # kilobits per second in tc's notation
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BURST_UNIT = "kbit" # kilobits in tc's notation
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# Those are RATES (bits per second) and SIZE (bytes) unit names from tc manual
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UNITS = {
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"k": 1,
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"m": 2,
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"g": 3,
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"t": 4
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}
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filters_pattern = re.compile(r"police \w+ rate (\w+) burst (\w+)")
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tbf_pattern = re.compile(
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r"qdisc (\w+) \w+: \w+ refcnt \d rate (\w+) burst (\w+) \w*")
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class InvalidKernelHzValue(exceptions.NeutronException):
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message = _("Kernel HZ value %(value)s is not valid. This value must be "
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"greater than 0.")
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class InvalidUnit(exceptions.NeutronException):
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message = _("Unit name '%(unit)s' is not valid.")
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def convert_to_kilobits(value, base):
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value = value.lower()
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if "bit" in value:
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input_in_bits = True
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value = value.replace("bit", "")
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else:
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input_in_bits = False
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value = value.replace("b", "")
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# if it is now bare number then it is in bits, so we return it simply
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if value.isdigit():
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value = int(value)
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if input_in_bits:
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return bits_to_kilobits(value, base)
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else:
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bits_value = bytes_to_bits(value)
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return bits_to_kilobits(bits_value, base)
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unit = value[-1:]
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if unit not in UNITS.keys():
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raise InvalidUnit(unit=unit)
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val = int(value[:-1])
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if input_in_bits:
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bits_value = val * (base ** UNITS[unit])
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else:
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bits_value = bytes_to_bits(val * (base ** UNITS[unit]))
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return bits_to_kilobits(bits_value, base)
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def bytes_to_bits(value):
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return value * 8
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def bits_to_kilobits(value, base):
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#NOTE(slaweq): round up that even 1 bit will give 1 kbit as a result
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return int((value + (base - 1)) / base)
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class TcCommand(ip_lib.IPDevice):
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def __init__(self, name, kernel_hz, namespace=None):
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if kernel_hz <= 0:
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raise InvalidKernelHzValue(value=kernel_hz)
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super(TcCommand, self).__init__(name, namespace=namespace)
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self.kernel_hz = kernel_hz
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def _execute_tc_cmd(self, cmd, **kwargs):
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cmd = ['tc'] + cmd
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ip_wrapper = ip_lib.IPWrapper(self.namespace)
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return ip_wrapper.netns.execute(cmd, run_as_root=True, **kwargs)
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def get_filters_bw_limits(self, qdisc_id=INGRESS_QDISC_ID):
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cmd = ['filter', 'show', 'dev', self.name, 'parent', qdisc_id]
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cmd_result = self._execute_tc_cmd(cmd)
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if not cmd_result:
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return None, None
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for line in cmd_result.split("\n"):
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m = filters_pattern.match(line.strip())
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if m:
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#NOTE(slaweq): because tc is giving bw limit in SI units
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# we need to calculate it as 1000bit = 1kbit:
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bw_limit = convert_to_kilobits(m.group(1), SI_BASE)
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#NOTE(slaweq): because tc is giving burst limit in IEC units
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# we need to calculate it as 1024bit = 1kbit:
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burst_limit = convert_to_kilobits(m.group(2), IEC_BASE)
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return bw_limit, burst_limit
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return None, None
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def get_tbf_bw_limits(self):
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cmd = ['qdisc', 'show', 'dev', self.name]
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cmd_result = self._execute_tc_cmd(cmd)
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if not cmd_result:
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return None, None
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m = tbf_pattern.match(cmd_result)
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if not m:
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return None, None
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qdisc_name = m.group(1)
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if qdisc_name != "tbf":
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return None, None
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#NOTE(slaweq): because tc is giving bw limit in SI units
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# we need to calculate it as 1000bit = 1kbit:
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bw_limit = convert_to_kilobits(m.group(2), SI_BASE)
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#NOTE(slaweq): because tc is giving burst limit in IEC units
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# we need to calculate it as 1024bit = 1kbit:
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burst_limit = convert_to_kilobits(m.group(3), IEC_BASE)
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return bw_limit, burst_limit
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def set_filters_bw_limit(self, bw_limit, burst_limit):
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"""Set ingress qdisc and filter for police ingress traffic on device
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This will allow to police traffic incoming to interface. It
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means that it is fine to limit egress traffic from instance point of
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view.
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"""
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#because replace of tc filters is not working properly and it's adding
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# new filters each time instead of replacing existing one first old
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# ingress qdisc should be deleted and then added new one so update will
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# be called to do that:
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return self.update_filters_bw_limit(bw_limit, burst_limit)
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def set_tbf_bw_limit(self, bw_limit, burst_limit, latency_value):
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"""Set token bucket filter qdisc on device
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This will allow to limit speed of packets going out from interface. It
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means that it is fine to limit ingress traffic from instance point of
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view.
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"""
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return self._replace_tbf_qdisc(bw_limit, burst_limit, latency_value)
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def update_filters_bw_limit(self, bw_limit, burst_limit,
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qdisc_id=INGRESS_QDISC_ID):
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self.delete_filters_bw_limit()
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return self._set_filters_bw_limit(bw_limit, burst_limit, qdisc_id)
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def update_tbf_bw_limit(self, bw_limit, burst_limit, latency_value):
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return self._replace_tbf_qdisc(bw_limit, burst_limit, latency_value)
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def delete_filters_bw_limit(self):
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#NOTE(slaweq): For limit traffic egress from instance we need to use
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# qdisc "ingress" because it is ingress traffic from interface POV:
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self._delete_qdisc("ingress")
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def delete_tbf_bw_limit(self):
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self._delete_qdisc("root")
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def _set_filters_bw_limit(self, bw_limit, burst_limit,
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qdisc_id=INGRESS_QDISC_ID):
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cmd = ['qdisc', 'add', 'dev', self.name, 'ingress',
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'handle', qdisc_id]
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self._execute_tc_cmd(cmd)
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return self._add_policy_filter(bw_limit, burst_limit)
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def _delete_qdisc(self, qdisc_name):
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cmd = ['qdisc', 'del', 'dev', self.name, qdisc_name]
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# Return_code=2 is fine because it means
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# "RTNETLINK answers: No such file or directory" what is fine when we
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# are trying to delete qdisc
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return self._execute_tc_cmd(cmd, extra_ok_codes=[2])
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def _get_filters_burst_value(self, bw_limit, burst_limit):
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if not burst_limit:
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# NOTE(slaweq): If burst value was not specified by user than it
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# will be set as 80% of bw_limit to ensure that limit for TCP
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# traffic will work well:
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return float(bw_limit) * 0.8
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return burst_limit
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def _get_tbf_burst_value(self, bw_limit, burst_limit):
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min_burst_value = float(bw_limit) / float(self.kernel_hz)
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return max(min_burst_value, burst_limit)
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def _replace_tbf_qdisc(self, bw_limit, burst_limit, latency_value):
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burst = "%s%s" % (
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self._get_tbf_burst_value(bw_limit, burst_limit), BURST_UNIT)
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latency = "%s%s" % (latency_value, LATENCY_UNIT)
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rate_limit = "%s%s" % (bw_limit, BW_LIMIT_UNIT)
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cmd = [
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'qdisc', 'replace', 'dev', self.name,
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'root', 'tbf',
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'rate', rate_limit,
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'latency', latency,
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'burst', burst
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]
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return self._execute_tc_cmd(cmd)
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def _add_policy_filter(self, bw_limit, burst_limit,
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qdisc_id=INGRESS_QDISC_ID):
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rate_limit = "%s%s" % (bw_limit, BW_LIMIT_UNIT)
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burst = "%s%s" % (
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self._get_filters_burst_value(bw_limit, burst_limit), BURST_UNIT)
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#NOTE(slaweq): it is made in exactly same way how openvswitch is doing
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# it when configuing ingress traffic limit on port. It can be found in
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# lib/netdev-linux.c#L4698 in openvswitch sources:
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cmd = [
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'filter', 'add', 'dev', self.name,
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'parent', qdisc_id, 'protocol', 'all',
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'prio', '49', 'basic', 'police',
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'rate', rate_limit,
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'burst', burst,
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'mtu', MAX_MTU_VALUE,
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'drop']
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return self._execute_tc_cmd(cmd)
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