diff options
| -rwxr-xr-x | source4/scripting/bin/samba_dnsupdate | 224 |
1 files changed, 223 insertions, 1 deletions
diff --git a/source4/scripting/bin/samba_dnsupdate b/source4/scripting/bin/samba_dnsupdate index 249f11f7a4..c5af17a759 100755 --- a/source4/scripting/bin/samba_dnsupdate +++ b/source4/scripting/bin/samba_dnsupdate @@ -34,5 +34,227 @@ from ldb import SCOPE_SUBTREE, SCOPE_BASE, LdbError import ldb from samba import glue from samba.auth import system_session +from samba.samdb import SamDB + +default_ttl = 900 + +parser = optparse.OptionParser("samba_dnsupdate") +sambaopts = options.SambaOptions(parser) +parser.add_option_group(sambaopts) +parser.add_option_group(options.VersionOptions(parser)) +parser.add_option("--verbose", action="store_true") + +creds = None +ccachename = None + +opts, args = parser.parse_args() + +if len(args) != 0: + parser.print_usage() + sys.exit(1) + +lp = sambaopts.get_loadparm() + +domain = lp.get("realm") +host = lp.get("netbios name") +IPs = glue.interface_ips(lp) +nsupdate_cmd = lp.get('nsupdate command') + +if len(IPs) == 0: + print "No IP interfaces - skipping DNS updates" + sys.exit(0) + + + +######################################################## +# get credentials if we haven't got them already +def get_credentials(lp): + from samba.credentials import Credentials + global ccachename, creds + if creds is not None: + return + creds = Credentials() + creds.guess(lp) + try: + creds.set_machine_account(lp) + except: + print "Failed to set machine account" + raise + + (tmp_fd, ccachename) = tempfile.mkstemp() + creds.get_named_ccache(lp, ccachename) + + +############################################# +# an object to hold a parsed DNS line +class dnsobj(object): + def __init__(self): + self.type = None + self.name = None + self.dest = None + self.port = None + self.ip = None + def __str__(self): + if d.type == "A": return "%s:%s:%s" % (self.type, self.name, self.ip) + if d.type == "SRV": return "%s:%s:%s:%s" % (self.type, self.name, self.dest, self.port) + if d.type == "CNAME": return "%s:%s:%s" % (self.type, self.name, self.dest) + + +################################################ +# parse a DNS line from +def parse_dns_line(line, sub_vars): + d = dnsobj() + subline = samba.substitute_var(line, sub_vars) + list = subline.split() + d.type = list[0] + d.name = list[1] + if d.type == 'SRV': + d.dest = list[2] + d.port = list[3] + elif d.type == 'A': + d.ip = list[2] # usually $IP, which gets replaced + elif d.type == 'CNAME': + d.dest = list[2] + else: + print "Received unexpected DNS reply of type %s" % d.type + raise + return d + +############################################ +# see if two hostnames match +def hostname_match(h1, h2): + h1 = str(h1) + h2 = str(h2) + return h1.lower().rstrip('.') == h2.lower().rstrip('.') + + +############################################ +# check that a DNS entry exists +def check_dns_name(d): + if opts.verbose: + print "Looking for DNS entry %s" % d + try: + ans = dns.resolver.query(d.name, d.type) + except dns.resolver.NXDOMAIN: + return False + if d.type == 'A': + # we need to be sure that our IP is there + for rdata in ans: + if str(rdata) == str(d.ip): + return True + if d.type == 'CNAME': + for i in range(len(ans)): + if hostname_match(ans[i].target, d.dest): + return True + if d.type == 'SRV': + if opts.verbose: + print "Got %u replies in SRV lookup for %s" % (len(ans), d.name) + for i in range(len(ans)): + rdata = ans[i] + if opts.verbose: + print "Checking %s against %s" % (rdata, d) + if str(rdata.port) == str(d.port) and hostname_match(rdata.target, d.dest): + return True + if opts.verbose: + print "Failed to find DNS entry %s" % d + return False + + +########################################### +# get the list of substitution vars +def get_subst_vars(): + global lp + vars = {} + + samdb = SamDB(url=lp.get("sam database"), session_info=system_session(), lp=lp) + + vars['DNSDOMAIN'] = lp.get('realm').lower() + vars['HOSTNAME'] = lp.get('netbios name').lower() + "." + vars['DNSDOMAIN'] + vars['NTDSGUID'] = samdb.get_ntds_GUID() + vars['SITE'] = samdb.server_site_name() + res = samdb.search(base=None, scope=SCOPE_BASE, attrs=["objectGUID"]) + guid = samdb.schema_format_value("objectGUID", res[0]['objectGUID'][0]) + vars['DOMAINGUID'] = guid + return vars + + +############################################ +# call nsupdate for an entry +def call_nsupdate(d): + global ccachename, nsupdate_cmd + + if opts.verbose: + print "Calling nsupdate for %s" % d + (tmp_fd, tmpfile) = tempfile.mkstemp() + f = os.fdopen(tmp_fd, 'w') + if d.type == "A": + f.write("update add %s %u A %s\n" % (d.name, default_ttl, d.ip)) + if d.type == "SRV": + f.write("update add %s %u SRV 0 100 %s %s\n" % (d.name, default_ttl, d.port, d.dest)) + if d.type == "CNAME": + f.write("update add %s %u SRV %s\n" % (d.name, default_ttl, d.dest)) + if opts.verbose: + f.write("show\n") + f.write("send\n") + f.close() + + os.putenv("KRB5CCNAME", ccachename) + os.system("%s %s" % (nsupdate_cmd, tmpfile)) + os.unlink(tmpfile) + + +# get the list of DNS entries we should have +dns_update_list = lp.private_path('dns_update_list') + +file = open(dns_update_list, "r") + +# get the substitution dictionary +sub_vars = get_subst_vars() + +# build up a list of update commands to pass to nsupdate +update_list = [] +dns_list = [] + +# read each line, and check that the DNS name exists +line = file.readline() +while line: + line = line.rstrip().lstrip() + if line[0] == "#": + line = file.readline() + continue + d = parse_dns_line(line, sub_vars) + dns_list.append(d) + line = file.readline() + +# now expand the entries, if any are A record with ip set to $IP +# then replace with multiple entries, one for each interface IP +for d in dns_list: + if d.type == 'A' and d.ip == "$IP": + d.ip = IPs[0] + for i in range(len(IPs)-1): + d2 = d + d2.ip = IPs[i+1] + dns_list.append(d2) + +# now check if the entries already exist on the DNS server +for d in dns_list: + if not check_dns_name(d): + update_list.append(d) + +if len(update_list) == 0: + if opts.verbose: + print "No DNS updates needed" + sys.exit(0) + +# get our krb5 creds +get_credentials(lp) + +# ask nsupdate to add entries as needed +for d in update_list: + call_nsupdate(d) + +# delete the ccache if we created it +if ccachename is not None: + os.unlink(ccachename) + -print "Updating Samba DNS entries - work in progress" |