http://www.cnblogs.com/xiaowuyi/p/3333276.html
一、进行dns访问
参数参考rfc http://www.ietf.org/rfc/rfc1035.txt
>>> default_dstIp="10.235.160.73"
>>> default_dstPort=5333
>>> default_srcProt=10000
>>> default_url="img01.xxxxcdn.com.danuoyi.com"
>>> ans=sr1(IP(dst=default_dstIp)/UDP(dport=default_dstPort)/DNS(qd=DNSQR(qname=default_url, qtype=1)), verbose=0)
>>> result = ans[DNS].show()
###[ DNS ]###
id = 0
qr = 0L
opcode = QUERY
aa = 0L
tc = 0L
rd = 0L
ra = 0L
z = 0L
rcode = ok
qdcount = 1
ancount = 0
nscount = 0
arcount = 0
\qd \
|###[ DNS Question Record ]###
| qname = 'img01.taobaocdn.com.danuoyi.tbcache.com.'
| qtype = A
| qclass = IN
an = None
ns = None
ar = None
>>> ans[DNS].command()
"DNS(aa=0L, qr=0L, an=None, nscount=0, qdcount=1, ns=None, tc=0L, rd=0L, arcount=0, ar=None, opcode=0L, ra=0L, z=0L, rcode=0L, id=0, ancount=0, qd=DNSQR(qclass=1, qtype=1, qname='img01.taobaocdn.com.danuoyi.tbcache.com.'))"
二、对相应结果的解析：
对于command返回的元素，本打算逐个元素解析，但因为格式是raw的，对ns对象解析的时候出现乱码；
一开始可能会解析出乱码的执行函数
| def exec_test(func): #print "Start %s case..."%func #print "Start to query DNS.....\n---Pharos address:%s\n---Client address:%s"%(dst,qname) resp = eval(func) # try: # an = eval(resp).an # qd = eval(resp).qd # rtjson = "" # anjson = "" # qdjson = "" # dnsjson = "" # if an<>None: # for key in vars(an)['fields']: # anjson = ",".join([anjson,"%s:%s"%(key,getattr(an, str(key)))]) # # if qd<>None: # for key in vars(qd)['fields']: # qdjson = ",".join([qdjson,"%s:%s"%(key,getattr(qd, str(key)))]) # # dns = eval(resp) # for key in vars(dns)['fields']: # if key not in ('an','qd'): # dnsjson = ",".join([dnsjson,"%s:%s"%(key,getattr(dns, str(key)))]) # # rtjson ='{"DNSRR":{%s},"DNSQR":{%s}%s}'%(anjson.lstrip(","),qdjson.lstrip(","), dnsjson) # print rtjson # # except: # print sys.exc_info() |
后改称通过索引得到key对应的value
| def getvaluebyName(org, name): index=org.index(name) index2=org.index(',', index) result = org[(index+len(name)+1):index2] if result[0] == "\'": result=result[1:len(result)-1] return result result = ans[DNS].command() |
