#!/opt/python/bin/python

import DNS
DNS.ParseResolvConf()

def Error(mesg):
    import sys
    print sys.argv[0],"ERROR:"
    print mesg
    sys.exit(1)

def main():
    import sys
    if len(sys.argv) != 2:
	Error("usage: %s somedomain.com"%sys.argv[0])
    domain = sys.argv[1]
    nslist = GetNS(domain)
    print "According to the primary, the following are nameservers for this domain"
    for ns in nslist:
	print "  ",ns
	CheckNS(ns,domain)


def GetNS(domain):
    import DNS
    r = DNS.Request(domain,qtype='SOA').req()
    if r.header['status'] != 'NOERROR':
	Error("received status of %s when attempting to look up SOA for domain"%
		(r.header['status']))
    primary,email,serial,refresh,retry,expire,minimum = r.answers[0]['data']
    print "Primary nameserver for domain %s is: %s"%(domain,primary)
    r = DNS.Request(domain,qtype='NS',server=primary,aa=1).req()
    if r.header['status'] != 'NOERROR':
	Error("received status of %s when attempting to query %s for NSs"%
		(r.header['status']))
    if r.header['aa'] != 1:
	Error("primary NS %s doesn't believe that it's authoritative!"% primary)
    nslist = map(lambda x:x['data'], r.answers)
    return nslist

def CheckNS(nameserver,domain):
    r = DNS.Request(domain,qtype='SOA',server=nameserver,aa=1).req()
    if r.header['status'] != 'NOERROR':
	Error("received status of %s when attempting to query %s for NS"%
		(r.header['status']))
    if r.header['aa'] != 1:
	Error("NS %s doesn't believe that it's authoritative!"% nameserver)
    primary,email,serial,refresh,retry,expire,minimum = r.answers[0]['data']
    print "      NS has serial",serial[1]

if __name__ == "__main__":
    main()