def configure_dns(self):
"""Generates BIND configuration files for DNS
Can check configs eg:
Forward::
bash-3.2$ named-checkzone -d AS3 ank_lab/netkit_lab/AS3_l3_3_dns_1/etc/bind/db.AS3
loading "AS3" from "ank_lab/netkit_lab/AS3_l3_3_dns_1/etc/bind/db.AS3" class "IN"
zone AS3/IN: loaded serial 2008080101
OK
Reverse::
bash-3.2$ named-checkzone -d 0.10.in-addr.arpa ank_lab/netkit_lab/AS3_l3_3_dns_1/etc/bind/db.0.10.in-addr.arpa.
loading "0.10.in-addr.arpa" from "ank_lab/netkit_lab/AS3_l3_3_dns_1/etc/bind/db.0.10.in-addr.arpa." class "IN"
zone 0.10.in-addr.arpa/IN: loaded serial 2008080101
OK
named::
bash-3.2$ named-checkconf ank_lab/netkit_lab/AS3_l3_3_dns_1/etc/bind/named.conf
"""
import netaddr
ip_localhost = netaddr.IPAddress("127.0.0.1")
linux_bind_dir = "/etc/bind"
resolve_template = lookup.get_template("linux/resolv.mako")
forward_template = lookup.get_template("bind/forward.mako")
named_template = lookup.get_template("bind/named.mako")
reverse_template = lookup.get_template("bind/reverse.mako")
root_template = lookup.get_template("bind/root.mako")
root_dns_template = lookup.get_template("bind/root_dns.mako")
root_dns_named_template = lookup.get_template("bind/root_dns_named.mako")
ip_as_allocs = ank.get_ip_as_allocs(self.network)
dns_servers = ank.dns_servers(self.network)
root_servers = list(ank.root_dns_servers(self.network))
auth_servers = ank.dns.dns_auth_servers(self.network)
caching_servers = ank.dns.dns_cache_servers(self.network)
clients = ank.dns.dns_clients(self.network)
routers = set(self.network.routers())
#TODO: use with for opening files
for server in root_servers:
children = ank.dns.dns_hiearchy_children(server)
child_servers = []
for child in children:
advertise_block = ip_as_allocs[child.asn]
reverse_identifier = ank.rev_dns_identifier(advertise_block)
child_servers.append( (child.domain, reverse_identifier, ank.server_ip(child)))
f_root_db = open(os.path.join(bind_dir(self.network, server), "db.root"), 'wb')
f_root_db.write( root_dns_template.render(
dns_servers = child_servers,
server = server,
))
f_named = open( os.path.join(bind_dir(self.network, server), "named.conf"), 'wb')
f_named.write(root_dns_named_template.render(
logging = False,
))
for server in caching_servers:
#root_db_hint = ( ("ns.AS%s" % n.asn, ank.server_ip(n)) for n in ank.dns_hiearchy_parents(server))
root_db_hint = ( ("ROOT-SERVER", ank.server_ip(n)) for n in root_servers)
root_db_hint = list(root_db_hint)
#TODO: make caching use parent rather than global root
f_root = open( os.path.join(bind_dir(self.network, server), "db.root"), 'wb')
f_root.write( root_template.render( root_servers = root_db_hint))
f_named = open( os.path.join(bind_dir(self.network, server), "named.conf"), 'wb')
f_named.write(named_template.render(
entry_list = [],
bind_dir = linux_bind_dir,
logging = False,
))
f_named.close()
for server in auth_servers:
named_list = []
advertise_links = list(ank.advertise_links(server))
advertise_hosts = list(ank.dns_auth_children(server))
LOG.debug("DNS server %s advertises %s" % (server, advertise_links))
#TODO: make reverse dns handle domains other than /8 /16 /24
advertise_block = ip_as_allocs[server.asn]
# remove trailing fullstop
reverse_identifier = ank.rev_dns_identifier(advertise_block).rstrip(".")
#TODO: look at using advertise_block.network.reverse_dns - check what Bind needs
named_list.append(reverse_identifier)
f_named = open( os.path.join(bind_dir(self.network, server), "named.conf"), 'wb')
f_named.write(named_template.render(
domain = server.domain,
entry_list = named_list,
bind_dir = linux_bind_dir,
logging = False,
))
f_named.close()
for_entry_list = list( (self.interface_id(link.id), link.local_host.dns_host_portion_only, link.ip)
for link in advertise_links)
# Add loopbacks for routers
for_entry_list += ( (self.lo_interface(0), host.dns_host_portion_only, host.lo_ip.ip)
#TODO: make thise check l3 group rather than asn (generalise)
for host in advertise_hosts if host.is_router and host.asn == server.asn)
rev_entry_list = list(
(ank.reverse_subnet(link.ip, advertise_block.prefixlen), self.interface_id(link.id), link.local_host.dns_hostname)
for link in advertise_links)
# Add loopbacks for routers
rev_entry_list += ( (ank.reverse_subnet(host.lo_ip.ip, advertise_block.prefixlen), self.lo_interface(0), host.dns_host_portion_only)
#TODO: make thise check l3 group rather than asn (generalise)
for host in advertise_hosts if host.is_router and host.asn == server.asn)
#TODO: provide better way to get eg eth0.host than string concat inside the template
host_cname_list = []
for host in advertise_hosts:
if host.asn != server.asn:
# host is from another asn, skip.
#TODO: extend this to make sure matches same asn, l3group and l2group
continue
if host.is_router:
# has lo_ip
cname = "%s.%s" % (self.lo_interface(), host.dns_host_portion_only)
else:
# choose an interface - arbitrary choice, choose first host link
interface = self.interface_id(ank.server_interface_id(host))
cname = "%s.%s" % (interface, host.dns_host_portion_only)
host_cname_list.append( (host.dns_host_portion_only, cname))
#Sort to make format nicer
host_cname_list = sorted(host_cname_list, key = lambda x: x[1])
for_entry_list = sorted(for_entry_list)
for_entry_list = sorted(for_entry_list, key = lambda x: x[1])
f_forward = open ( os.path.join(bind_dir(self.network, server), "db.%s" % server.domain), 'wb')
f_forward.write(forward_template.render(
domain = server.domain,
entry_list = for_entry_list,
host_cname_list = host_cname_list,
dns_server = server.dns_hostname,
dns_server_ip = ank.server_ip(server),
))
f_reverse = open(os.path.join(bind_dir(self.network, server), "db.%s" % reverse_identifier), 'wb')
f_reverse.write(reverse_template.render(
domain = server.domain,
identifier = reverse_identifier,
entry_list = rev_entry_list,
dns_server= server.dns_hostname,
))
#TODO: make l2 use l3 for caching
#TODO: ROOT-SERVER can't be part of a domain... - need to correctly handle case of multiple root servers
# and also need to handle this for case of single root server (ie no hiearchy) probably ok as /etc/resolv.conf points to server itself, not through dns hints
root_db_hint = ( ("ROOT-SERVER", ank.server_ip(n)) for n in ank.dns_hiearchy_parents(server))
f_root = open( os.path.join(bind_dir(self.network, server), "db.root"), 'wb')
f_root.write( root_template.render( root_servers = root_db_hint))
for server in dns_servers:
f_resolv = open( os.path.join(etc_dir(self.network, server), "resolv.conf"), 'wb')
f_resolv.write ( resolve_template.render(
nameservers = [ank.server_ip(server)],
domain = server.domain))
# Configure clients
for client in clients:
server_ips = (ank.server_ip(server) for server in ank.dns_hiearchy_parents(client))
server_ips = list(server_ips)
f_resolv = open( os.path.join(etc_dir(self.network, client), "resolv.conf"), 'wb')
f_resolv.write ( resolve_template.render(
nameservers = server_ips,
domain = client.domain))
return
