python - 运行本地 python DNS 服务器时出现 Keyerror

Question

我正在尝试使用包含的 .zone 文件运行此脚本： https ://github.com/howCodeORG/howDNS

我在 / 中有 DNS.py，在 /zones 中有 .zone。

当我dig howcode.org @127.0.0.1

我得到：

Traceback (most recent call last):
  File "/dns.py", line 171, in <module>
    r = buildresponse(data)
  File "/dns.py", line 145, in buildresponse
    ANCOUNT = len(getrecs(data[12:])[0]).to_bytes(2, byteorder='big')
  File "/dns.py", line 96, in getrecs
    zone = getzone(domain)
  File "/dns.py", line 88, in getzone
    return zonedata[zone_name]
KeyError: 'howcode.org.'

将文件移动到 ~/desktop/DNS 文件夹以再次运行，并对代码进行一些调整以尝试获得更直接的 DNS 路由

import socket, glob, json

port = 53
ip = '127.0.0.1'

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind((ip, port))

def load_zones():

    jsonzone = {}
    zonefiles = glob.glob('zones/*.zone')

    for zone in zonefiles:
        with open(zone) as zonedata:
            data = json.load(zonedata)
            zonename = data["$origin"]
            jsonzone[zonename] = data
    return jsonzone

zonedata = load_zones()

def getflags(flags):

    byte1 = bytes(flags[:1])
    byte2 = bytes(flags[1:2])

    rflags = ''

    QR = '1'

    OPCODE = ''
    for bit in range(1,5):
        OPCODE += str(ord(byte1)&(1<<bit))

    AA = '1'

    TC = '0'

    RD = '0'

    # Byte 2

    RA = '0'

    Z = '000'

    RCODE = '0000'

    return int(QR+OPCODE+AA+TC+RD, 2).to_bytes(1, byteorder='big')+int(RA+Z+RCODE, 2).to_bytes(1, byteorder='big')

def getquestiondomain(data):

    state = 0
    expectedlength = 0
    domainstring = ''
    domainparts = []
    x = 0
    y = 0
    for byte in data:
        if state == 1:
            if byte != 0:
                domainstring += chr(byte)
            x += 1
            if x == expectedlength:
                domainparts.append(domainstring)
                domainstring = ''
                state = 0
                x = 0
            if byte == 0:
                domainparts.append(domainstring)
                break
        else:
            state = 1
            expectedlength = byte
        y += 1

    questiontype = data[y:y+2]

    return (domainparts, questiontype)

def getzone(domain):
    global zonedata

    zone_name = '.'.join(domain)
    return zonedata[zone_name]

def getrecs(data):
    domain, questiontype = getquestiondomain(data)
    qt = ''
    if questiontype == b'\x00\x01':
        qt = 'a'

    zone = getzone(domain)

    return (zone[qt], qt, domain)

def buildquestion(domainname, rectype):
    qbytes = b''

    for part in domainname:
        length = len(part)
        qbytes += bytes([length])

        for char in part:
            qbytes += ord(char).to_bytes(1, byteorder='big')

    if rectype == 'a':
        qbytes += (1).to_bytes(2, byteorder='big')

    qbytes += (1).to_bytes(2, byteorder='big')

    return qbytes

def rectobytes(domainname, rectype, recttl, recval):

    rbytes = b'\xc0\x0c'

    if rectype == 'a':
        rbytes = rbytes + bytes([0]) + bytes([1])

    rbytes = rbytes + bytes([0]) + bytes([1])

    rbytes += int(recttl).to_bytes(4, byteorder='big')

    if rectype == 'a':
        rbytes = rbytes + bytes([0]) + bytes([4])

        for part in recval.split('.'):
            rbytes += bytes([int(part)])
    return rbytes

def buildresponse(data):

    # Transaction ID
    TransactionID = data[:2]

    # Get the flags
    Flags = getflags(data[2:4])

    # Question Count
    QDCOUNT = b'\x00\x01'

    # Answer Count
    ANCOUNT = len(getrecs(data[12:])[0]).to_bytes(2, byteorder='big')

    # Nameserver Count
    NSCOUNT = (0).to_bytes(2, byteorder='big')

    # Additonal Count
    ARCOUNT = (0).to_bytes(2, byteorder='big')

    dnsheader = TransactionID+Flags+QDCOUNT+ANCOUNT+NSCOUNT+ARCOUNT

    # Create DNS body
    dnsbody = b''

    # Get answer for query
    records, rectype, domainname = getrecs(data[12:])

    dnsquestion = buildquestion(domainname, rectype)

    for record in records:
        dnsbody += rectobytes(domainname, rectype, record["ttl"], record["value"])

    return dnsheader + dnsquestion + dnsbody


while 1:
    data, addr = sock.recvfrom(512)
    r = buildresponse(data)
    sock.sendto(r, addr)

预期结果：

dig howcode.org @127.0.0.1

; <<>> DiG 9.8.3-P1 <<>> howcode.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45939
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;howcode.org.           IN  A

;; ANSWER SECTION:
howcode.org.        300 IN  A   255.255.255.255
howcode.org.        300 IN  A   127.0.0.1
howcode.org.        300 IN  A   127.0.0.1
howcode.org.        300 IN  A   127.0.0.1
howcode.org.        300 IN  A   10.10.10.10

;; Query time: 54 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Aug 21 22:59:04 2019
;; MSG SIZE  rcvd: 61

标签： pythonjsonserverdns