diff options
| -rw-r--r-- | cloudinit/net/__init__.py | 82 |
1 files changed, 80 insertions, 2 deletions
diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py index 799cb97e..b45153f4 100644 --- a/cloudinit/net/__init__.py +++ b/cloudinit/net/__init__.py @@ -20,6 +20,7 @@ import errno import glob import os import re +import string from cloudinit import log as logging from cloudinit import util @@ -46,6 +47,8 @@ NET_CONFIG_BRIDGE_OPTIONS = [ "bridge_hello", "bridge_maxage", "bridge_maxwait", "bridge_stp", ] +DEFAULT_PRIMARY_INTERFACE = 'eth0' + def sys_dev_path(devname, path=""): return SYS_CLASS_NET + devname + "/" + path @@ -442,8 +445,83 @@ def is_disabled_cfg(cfg): def generate_fallback_config(): - # FIXME: add implementation here - return None + """Determine which attached net dev is most likely to have a connection and + generate network state to run dhcp on that interface""" + # by default use eth0 as primary interface + nconf = {'config': {'interfaces': {}, + 'dns': {'search': [], 'nameservers': []}, 'routes': [] + }, + 'version': 1 + } + + # get list of interfaces that could have connections + invalid_interfaces = set(['lo']) + potential_interfaces = set(os.listdir(SYS_CLASS_NET)) + potential_interfaces = potential_interfaces.difference(invalid_interfaces) + # sort into interfaces with carrier, interfaces which could have carrier, + # and ignore interfaces that are definitely disconnected + connected = [] + possibly_connected = [] + for interface in potential_interfaces: + try: + sysfs_carrier = os.path.join(SYS_CLASS_NET, interface, 'carrier') + carrier = int(util.load_file(sysfs_carrier).strip()) + if carrier: + connected.append(interface) + continue + except OSError: + pass + # check if nic is dormant or down, as this may make a nick appear to + # not have a carrier even though it could acquire one when brought + # online by dhclient + try: + sysfs_dormant = os.path.join(SYS_CLASS_NET, interface, 'dormant') + dormant = int(util.load_file(sysfs_dormant).strip()) + if dormant: + possibly_connected.append(interface) + continue + except OSError: + pass + try: + sysfs_operstate = os.path.join(SYS_CLASS_NET, interface, + 'operstate') + operstate = util.load_file(sysfs_operstate).strip() + if operstate in ['dormant', 'down', 'lowerlayerdown', 'unknown']: + possibly_connected.append(interface) + continue + except OSError: + pass + + # don't bother with interfaces that might not be connected if there are + # some that definitely are + if connected: + potential_interfaces = connected + else: + potential_interfaces = possibly_connected + # if there are no interfaces, give up + if not potential_interfaces: + return + # if eth0 exists use it above anything else, otherwise get the interface + # that looks 'first' + if DEFAULT_PRIMARY_INTERFACE in potential_interfaces: + name = DEFAULT_PRIMARY_INTERFACE + else: + potential_interfaces.sort( + key=lambda x: int(''.join(i for i in x if i in string.digits))) + name = potential_interfaces[0] + + sysfs_mac = os.path.join(SYS_CLASS_NET, name, 'address') + mac = util.load_file(sysfs_mac).strip() + target_name = name + + # generate net config for interface + nconf['config']['interfaces'][target_name] = { + 'mac_address': mac, 'name': target_name, 'type': 'physical', + 'mode': 'manual', 'inet': 'inet', + 'subnets': [{'type': 'dhcp4'}, {'type': 'dhcp6'}] + } + + return nconf def read_kernel_cmdline_config(): |