Source code for ironic_python_agent.netutils

# Copyright 2014 Rackspace, Inc.
# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

import ctypes
import fcntl
import select
import socket
import struct
import sys

import netifaces
from oslo_config import cfg
from oslo_log import log as logging
from oslo_utils import netutils

from ironic_python_agent import utils

LOG = logging.getLogger(__name__)


# LLDP definitions needed to extract vlan information
# 802.1Q defines from, Annex D
LLDP_802dot1_OUI = "0080c2"
# subtypes
dot1_VLAN_NAME = "03"
VLAN_ID_LEN = len(LLDP_802dot1_OUI + dot1_VLAN_NAME)

[docs]class ifreq(ctypes.Structure): """Class for setting flags on a socket.""" _fields_ = [("ifr_ifrn", ctypes.c_char * 16), ("ifr_flags", ctypes.c_short)]
[docs]class RawPromiscuousSockets(object): def __init__(self, interface_names, protocol): """Initialize context manager. :param interface_names: a list of interface names to bind to :param protocol: the protocol to listen for :returns: A list of tuple of (interface_name, bound_socket), or [] if there is an exception binding or putting the sockets in promiscuous mode """ if not interface_names: raise ValueError('interface_names must be a non-empty list of ' 'network interface names to bind to.') self.protocol = protocol # A 3-tuple of (interface_name, socket, ifreq object) self.interfaces = [(name, self._get_socket(), ifreq()) for name in interface_names] def __enter__(self): for interface_name, sock, ifr in self.interfaces:'Interface %s entering promiscuous mode to capture ', interface_name) try: ifr.ifr_ifrn = interface_name.encode() # Get current flags fcntl.ioctl(sock.fileno(), SIOCGIFFLAGS, ifr) # G for Get # bitwise or the flags with promiscuous mode, set the new flags ifr.ifr_flags |= IFF_PROMISC fcntl.ioctl(sock.fileno(), SIOCSIFFLAGS, ifr) # S for Set # Bind the socket so it can be used LOG.debug('Binding interface %(interface)s for protocol ' '%(proto)s', {'interface': interface_name, 'proto': self.protocol}) sock.bind((interface_name, self.protocol)) except Exception: LOG.error('Failed to open all RawPromiscuousSockets, ' 'attempting to close any opened sockets.') self.__exit__(*sys.exc_info()) raise # No need to return each interfaces ifreq. return [(sock[0], sock[1]) for sock in self.interfaces] def __exit__(self, exception_type, exception_val, trace): for name, sock, ifr in self.interfaces: # bitwise or with the opposite of promiscuous mode to remove ifr.ifr_flags &= ~IFF_PROMISC try: fcntl.ioctl(sock.fileno(), SIOCSIFFLAGS, ifr) sock.close() except Exception: LOG.exception('Failed to close raw socket for interface %s', name) def _get_socket(self): return socket.socket(socket.AF_PACKET, socket.SOCK_RAW, self.protocol)
[docs]def get_lldp_info(interface_names): """Get LLDP info from the switch(es) the agent is connected to. Listens on either a single or all interfaces for LLDP packets, then parses them. If no LLDP packets are received before lldp_timeout, returns a dictionary in the form {'interface': [],...}. :param interface_names: The interface to listen for packets on. If None, will listen on each interface. :return: A dictionary in the form {'interface': [(lldp_type, lldp_data)],...} """ with RawPromiscuousSockets(interface_names, LLDP_ETHERTYPE) as interfaces: try: return _get_lldp_info(interfaces) except Exception as e: LOG.exception('Error while getting LLDP info: %s', str(e)) raise
def _parse_tlv(buff): """Iterate over a buffer and generate structured TLV data. :param buff: An ethernet packet with the header trimmed off (first 14 bytes) """ lldp_info = [] while len(buff) >= 2: # TLV structure: type (7 bits), length (9 bits), val (0-511 bytes) tlvhdr = struct.unpack('!H', buff[:2])[0] tlvtype = (tlvhdr & 0xfe00) >> 9 tlvlen = (tlvhdr & 0x01ff) tlvdata = buff[2:tlvlen + 2] buff = buff[tlvlen + 2:] lldp_info.append((tlvtype, tlvdata)) if buff: LOG.warning("Trailing byte received in an LLDP package: %r", buff) return lldp_info def _receive_lldp_packets(sock): """Receive LLDP packets and process them. :param sock: A bound socket :return: A list of tuples in the form (lldp_type, lldp_data) """ pkt = sock.recv(1600) # Filter invalid packets if not pkt or len(pkt) < 14: return [] # Skip header (dst MAC, src MAC, ethertype) pkt = pkt[14:] return _parse_tlv(pkt) def _get_lldp_info(interfaces): """Wait for packets on each socket, parse the received LLDP packets.""" LOG.debug('Getting LLDP info for interfaces %s', interfaces) lldp_info = {} if not interfaces: return {} while interfaces:'Waiting on LLDP info for interfaces: %(interfaces)s, ' 'timeout: %(timeout)s', {'interfaces': interfaces, 'timeout': CONF.lldp_timeout}) socks = [interface[1] for interface in interfaces] # rlist is a list of sockets ready for reading rlist, _, _ =, [], [], CONF.lldp_timeout) if not rlist: # Empty read list means timeout on all interfaces LOG.warning('LLDP timed out, remaining interfaces: %s', interfaces) break for s in rlist: # Find interface name matching socket ready for read # Create a copy of interfaces to avoid deleting while iterating. for index, interface in enumerate(list(interfaces)): if s == interface[1]: try: lldp_info[interface[0]] = _receive_lldp_packets(s) except socket.error: LOG.exception('Socket for network interface %s said ' 'that it was ready to read we were ' 'unable to read from the socket while ' 'trying to get LLDP packet. Skipping ' 'this network interface.', interface[0]) else:'Found LLDP info for interface: %s', interface[0]) # Remove interface from the list, only need one packet del interfaces[index] # Add any interfaces that didn't get a packet as empty lists for name, _sock in interfaces: lldp_info[name] = [] return lldp_info
[docs]def get_default_ip_addr(type, interface_id): """Retrieve default IPv4 or IPv6 address.""" try: addrs = netifaces.ifaddresses(interface_id) return addrs[type][0]['addr'] except (ValueError, IndexError, KeyError): # No default IP address found return None
[docs]def get_ipv4_addr(interface_id): return get_default_ip_addr(netifaces.AF_INET, interface_id)
[docs]def get_ipv6_addr(interface_id): return get_default_ip_addr(netifaces.AF_INET6, interface_id)
[docs]def get_mac_addr(interface_id): try: addrs = netifaces.ifaddresses(interface_id) return addrs[netifaces.AF_LINK][0]['addr'] except (ValueError, IndexError, KeyError): # No mac address found return None
# Other options... # 1. import os; os.uname()[1] # 2. import platform; platform.node()
[docs]def get_hostname(): return socket.gethostname()
[docs]def interface_has_carrier(interface_name): path = '/sys/class/net/{}/carrier'.format(interface_name) try: with open(path, 'rt') as fp: return == '1' except EnvironmentError: LOG.debug('No carrier information for interface %s', interface_name) return False
[docs]def wrap_ipv6(ip): if netutils.is_valid_ipv6(ip): return "[%s]" % ip return ip
[docs]def get_wildcard_address(): if netutils.is_ipv6_enabled(): return "::" return ""
def _get_configured_vlans(): return [x.strip() for x in CONF.enable_vlan_interfaces.split(',') if x.strip()] def _add_vlan_interface(interface, vlan, interfaces_list): vlan_name = interface + '.' + vlan # if any(x for x in interfaces_list if == vlan_name): if any( == vlan_name for x in interfaces_list):"VLAN interface %s has already been added", vlan_name) return '' try:'Adding VLAN interface %s', vlan_name) # Add the interface utils.execute('ip', 'link', 'add', 'link', interface, 'name', vlan_name, 'type', 'vlan', 'id', vlan, check_exit_code=[0, 2]) # Bring up interface utils.execute('ip', 'link', 'set', 'dev', vlan_name, 'up') except Exception as exc: LOG.warning('Exception when running ip commands to add VLAN ' 'interface: %s', exc) return '' return vlan_name def _add_vlans_from_lldp(lldp, interface, interfaces_list): interfaces = [] # Get the lldp packets received on this interface if lldp: for type, value in lldp: if (type == LLDP_TLV_ORG_SPECIFIC and value.startswith(LLDP_802dot1_OUI + dot1_VLAN_NAME)): vlan = str(int(value[VLAN_ID_LEN: VLAN_ID_LEN + 4], 16)) name = _add_vlan_interface(interface, vlan, interfaces_list) if name: interfaces.append(name) else: LOG.debug('VLAN interface %s does not have lldp info', interface) return interfaces
[docs]def bring_up_vlan_interfaces(interfaces_list): """Bring up vlan interfaces based on kernel params Use the configured value of ``enable_vlan_interfaces`` to determine if VLAN interfaces should be brought up using ``ip`` commands. If ``enable_vlan_interfaces`` defines a particular vlan then bring up that vlan. If it defines an interface or ``all`` then use LLDP info to figure out which VLANs should be brought up. :param interfaces_list: List of current interfaces :return: List of vlan interface names that have been added """ interfaces = [] vlan_interfaces = _get_configured_vlans() for vlan_int in vlan_interfaces: # TODO(bfournie) skip if pxe boot interface if '.' in vlan_int: # interface and vlan are provided interface, vlan = vlan_int.split('.', 1) if any( == interface for x in interfaces_list): name = _add_vlan_interface(interface, vlan, interfaces_list) if name: interfaces.append(name) else: LOG.warning('Provided VLAN interface %s does not exist', interface) elif CONF.collect_lldp: # Get the vlans from lldp info if vlan_int == 'all': # Use all interfaces for iface in interfaces_list: names = _add_vlans_from_lldp( iface.lldp,, interfaces_list) if names: interfaces.extend(names) else: # Use provided interface lldp = next((x.lldp for x in interfaces_list if == vlan_int), None) if lldp: names = _add_vlans_from_lldp(lldp, vlan_int, interfaces_list) if names: interfaces.extend(names) else: LOG.warning('Provided interface name %s was not found', vlan_int) else: LOG.warning('Attempting to add VLAN interfaces but specific ' 'interface not provided and LLDP not enabled') return interfaces