# Author: Ben Howard  <bh@digitalocean.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

import json
import random

from cloudinit import log as logging
from cloudinit import net as cloudnet
from cloudinit import url_helper
from cloudinit import util

NIC_MAP = {'public': 'eth0', 'private': 'eth1'}

LOG = logging.getLogger(__name__)


def assign_ipv4_link_local(nic=None):
    """Bring up NIC using an address using link-local (ip4LL) IPs. On
       DigitalOcean, the link-local domain is per-droplet routed, so there
       is no risk of collisions. However, to be more safe, the ip4LL
       address is random.
    """

    if not nic:
        for cdev in sorted(cloudnet.get_devicelist()):
            if cloudnet.is_physical(cdev):
                nic = cdev
                LOG.debug("assigned nic '%s' for link-local discovery", nic)
                break

    if not nic:
        raise RuntimeError("unable to find interfaces to access the"
                           "meta-data server. This droplet is broken.")

    addr = "169.254.{0}.{1}/16".format(random.randint(1, 168),
                                       random.randint(0, 255))

    ip_addr_cmd = ['ip', 'addr', 'add', addr, 'dev', nic]
    ip_link_cmd = ['ip', 'link', 'set', 'dev', nic, 'up']

    if not util.which('ip'):
        raise RuntimeError("No 'ip' command available to configure ip4LL "
                           "address")

    try:
        (result, _err) = util.subp(ip_addr_cmd)
        LOG.debug("assigned ip4LL address '%s' to '%s'", addr, nic)

        (result, _err) = util.subp(ip_link_cmd)
        LOG.debug("brought device '%s' up", nic)
    except Exception:
        util.logexc(LOG, "ip4LL address assignment of '%s' to '%s' failed."
                         " Droplet networking will be broken", addr, nic)
        raise

    return nic


def del_ipv4_link_local(nic=None):
    """Remove the ip4LL address. While this is not necessary, the ip4LL
       address is extraneous and confusing to users.
    """
    if not nic:
        LOG.debug("no link_local address interface defined, skipping link "
                  "local address cleanup")
        return

    LOG.debug("cleaning up ipv4LL address")

    ip_addr_cmd = ['ip', 'addr', 'flush', 'dev', nic]

    try:
        (result, _err) = util.subp(ip_addr_cmd)
        LOG.debug("removed ip4LL addresses from %s", nic)

    except Exception as e:
        util.logexc(LOG, "failed to remove ip4LL address from '%s'.", nic, e)


def convert_network_configuration(config, dns_servers):
    """Convert the DigitalOcean Network description into Cloud-init's netconfig
       format.

       Example JSON:
        {'public': [
              {'mac': '04:01:58:27:7f:01',
               'ipv4': {'gateway': '45.55.32.1',
                        'netmask': '255.255.224.0',
                        'ip_address': '45.55.50.93'},
               'anchor_ipv4': {
                        'gateway': '10.17.0.1',
                        'netmask': '255.255.0.0',
                        'ip_address': '10.17.0.9'},
               'type': 'public',
               'ipv6': {'gateway': '....',
                        'ip_address': '....',
                        'cidr': 64}}
           ],
          'private': [
              {'mac': '04:01:58:27:7f:02',
               'ipv4': {'gateway': '10.132.0.1',
                        'netmask': '255.255.0.0',
                        'ip_address': '10.132.75.35'},
               'type': 'private'}
           ]
        }
    """

    def _get_subnet_part(pcfg, nameservers=None):
        subpart = {'type': 'static',
                   'control': 'auto',
                   'address': pcfg.get('ip_address'),
                   'gateway': pcfg.get('gateway')}

        if nameservers:
            subpart['dns_nameservers'] = nameservers

        if ":" in pcfg.get('ip_address'):
            subpart['address'] = "{0}/{1}".format(pcfg.get('ip_address'),
                                                  pcfg.get('cidr'))
        else:
            subpart['netmask'] = pcfg.get('netmask')

        return subpart

    all_nics = []
    for k in ('public', 'private'):
        if k in config:
            all_nics.extend(config[k])

    macs_to_nics = cloudnet.get_interfaces_by_mac()
    nic_configs = []

    for nic in all_nics:

        mac_address = nic.get('mac')
        sysfs_name = macs_to_nics.get(mac_address)
        nic_type = nic.get('type', 'unknown')
        # Note: the entry 'public' above contains a list, but
        # the list will only ever have one nic inside it per digital ocean.
        # If it ever had more than one nic, then this code would
        # assign all 'public' the same name.
        if_name = NIC_MAP.get(nic_type, sysfs_name)

        LOG.debug("mapped %s interface to %s, assigning name of %s",
                  mac_address, sysfs_name, if_name)

        ncfg = {'type': 'physical',
                'mac_address': mac_address,
                'name': if_name}

        subnets = []
        for netdef in ('ipv4', 'ipv6', 'anchor_ipv4', 'anchor_ipv6'):
            raw_subnet = nic.get(netdef, None)
            if not raw_subnet:
                continue

            sub_part = _get_subnet_part(raw_subnet)
            if nic_type == 'public' and 'anchor' not in netdef:
                # add DNS resolvers to the public interfaces only
                sub_part = _get_subnet_part(raw_subnet, dns_servers)
            else:
                # remove the gateway any non-public interfaces
                if 'gateway' in sub_part:
                    del sub_part['gateway']

            subnets.append(sub_part)

        ncfg['subnets'] = subnets
        nic_configs.append(ncfg)
        LOG.debug("nic '%s' configuration: %s", if_name, ncfg)

    return {'version': 1, 'config': nic_configs}


def read_metadata(url, timeout=2, sec_between=2, retries=30):
    response = url_helper.readurl(url, timeout=timeout,
                                  sec_between=sec_between, retries=retries)
    if not response.ok():
        raise RuntimeError("unable to read metadata at %s" % url)
    return json.loads(response.contents.decode())


def read_sysinfo():
    # DigitalOcean embeds vendor ID and instance/droplet_id in the
    # SMBIOS information

    # Detect if we are on DigitalOcean and return the Droplet's ID
    vendor_name = util.read_dmi_data("system-manufacturer")
    if vendor_name != "DigitalOcean":
        return (False, None)

    droplet_id = util.read_dmi_data("system-serial-number")
    if droplet_id:
        LOG.debug("system identified via SMBIOS as DigitalOcean Droplet: %s",
                  droplet_id)
    else:
        msg = ("system identified via SMBIOS as a DigitalOcean "
               "Droplet, but did not provide an ID. Please file a "
               "support ticket at: "
               "https://cloud.digitalocean.com/support/tickets/new")
        LOG.critical(msg)
        raise RuntimeError(msg)

    return (True, droplet_id)

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