Source code for oioioi.ipdnsauth.backends

import logging
import socket

from django.contrib.auth.backends import ModelBackend
from django.contrib.auth.models import User
from django.utils.translation import gettext_lazy as _

logger = logging.getLogger(__name__)


class IpDnsBackend(ModelBackend):
    """Authenticates users by their ip or dns hostname.

    This backend checks given arguments against models
    :class:'IpToUser' and :class:'DnsToUser' (in this order).
    When dns_name is not given, then it tries to call
    reverse-dns service on ip_addr.
    """

    description = _("IP/DNS based authentication")
    supports_authentication = True

    def authenticate(self, request, dns_name=None, ip_addr=None, **kwargs):
        if ip_addr:
            try:
                return User.objects.get(iptouser__ip_addr=ip_addr)
            except User.DoesNotExist:
                pass

        hostname = dns_name or self._resolve_hostname(ip_addr)
        if hostname:
            try:
                return User.objects.get(dnstouser__dns_name=hostname)
            except User.DoesNotExist:
                pass

        return None

    def _resolve_hostname(self, ip):
        if ip:
            try:
                logger.info("DNS Q %s", ip)
                name = socket.gethostbyaddr(ip)[0]
                logger.info("DNS + %s -> %s.", ip, name)
                return name
            except socket.herror:
                logger.info("DNS - %s", ip)
                pass

        return None