mirror of
https://github.com/Hopiu/linkchecker.git
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5d50f430d4
git-svn-id: https://linkchecker.svn.sourceforge.net/svnroot/linkchecker/trunk/linkchecker@356 e7d03fd6-7b0d-0410-9947-9c21f3af8025
591 lines
16 KiB
Python
591 lines
16 KiB
Python
# Domain Name Server (DNS) interface
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#
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# See RFC 1035:
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# ------------------------------------------------------------------------
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# Network Working Group P. Mockapetris
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# Request for Comments: 1035 ISI
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# November 1987
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# Obsoletes: RFCs 882, 883, 973
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#
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# DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION
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# ------------------------------------------------------------------------
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import DNS.Type
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import DNS.Class
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import DNS.Opcode
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import DNS.Status
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from DNS import Error
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# Low-level 16 and 32 bit integer packing and unpacking
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def pack16bit(n):
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return chr((n>>8)&0xFF) + chr(n&0xFF)
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def pack32bit(n):
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return chr((n>>24)&0xFF) + chr((n>>16)&0xFF) \
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+ chr((n>>8)&0xFF) + chr(n&0xFF)
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def unpack16bit(s):
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return (ord(s[0])<<8) | ord(s[1])
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def unpack32bit(s):
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return (ord(s[0])<<24) | (ord(s[1])<<16) \
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| (ord(s[2])<<8) | ord(s[3])
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def addr2bin(addr):
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if type(addr) == type(0):
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return addr
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bytes = addr.split('.')
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if len(bytes) != 4: raise ValueError, 'bad IP address'
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n = 0
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for byte in bytes: n = n<<8 | int(byte)
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return n
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def bin2addr(n):
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return '%d.%d.%d.%d' % ((n>>24)&0xFF, (n>>16)&0xFF,
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(n>>8)&0xFF, n&0xFF)
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# Packing class
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class PackError(Error):
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pass
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class Packer:
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def __init__(self):
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self.buf = ''
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self.index = {}
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def getbuf(self):
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return self.buf
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def addbyte(self, c):
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if len(c) != 1: raise TypeError, 'one character expected'
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self.buf = self.buf + c
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def addbytes(self, bytes):
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self.buf = self.buf + bytes
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def add16bit(self, n):
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self.buf = self.buf + pack16bit(n)
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def add32bit(self, n):
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self.buf = self.buf + pack32bit(n)
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def addaddr(self, addr):
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n = addr2bin(addr)
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self.buf = self.buf + pack32bit(n)
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def addstring(self, s):
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self.addbyte(chr(len(s)))
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self.addbytes(s)
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def addname(self, name):
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# Domain name packing (section 4.1.4)
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# Add a domain name to the buffer, possibly using pointers.
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# The case of the first occurrence of a name is preserved.
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# Redundant dots are ignored.
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lst = []
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for label in name.split('.'):
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if label:
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if len(label) > 63:
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raise PackError, 'label too long'
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lst.append(label)
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keys = []
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for i in range(len(lst)):
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key = '.'.join(lst[i:]).upper()
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keys.append(key)
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if self.index.has_key(key):
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pointer = self.index[key]
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break
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else:
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i = len(lst)
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pointer = None
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# Do it into temporaries first so exceptions don't
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# mess up self.index and self.buf
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buf = ''
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offset = len(self.buf)
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index = []
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for j in range(i):
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label = lst[j]
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n = len(label)
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if offset + len(buf) < 0x3FFF:
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index.append((keys[j], offset + len(buf)))
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else:
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print 'DNS.Lib.Packer.addname:',
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print 'warning: pointer too big'
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buf += chr(n) + label
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if pointer:
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buf += pack16bit(pointer | 0xC000)
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else:
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buf += '\0'
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self.buf = self.buf + buf
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for key, value in index:
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self.index[key] = value
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def dump(self):
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keys = self.index.keys()
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keys.sort()
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print '-'*40
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for key in keys:
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print '%20s %3d' % (key, self.index[key])
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print '-'*40
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space = 1
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for i in range(0, len(self.buf)+1, 2):
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if self.buf[i:i+2] == '**':
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if not space: print
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space = 1
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continue
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space = 0
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print '%4d' % i,
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for c in self.buf[i:i+2]:
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if ' ' < c < '\177':
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print ' %c' % c,
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else:
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print '%2d' % ord(c),
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print
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print '-'*40
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# Unpacking class
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class UnpackError(Error):
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pass
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class Unpacker:
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def __init__(self, buf):
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self.buf = buf
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self.offset = 0
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def getbyte(self):
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c = self.buf[self.offset]
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self.offset = self.offset + 1
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return c
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def getbytes(self, n):
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s = self.buf[self.offset : self.offset + n]
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if len(s) != n: raise UnpackError, 'not enough data left'
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self.offset = self.offset + n
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return s
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def get16bit(self):
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return unpack16bit(self.getbytes(2))
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def get32bit(self):
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return unpack32bit(self.getbytes(4))
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def getaddr(self):
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return bin2addr(self.get32bit())
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def getstring(self):
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return self.getbytes(ord(self.getbyte()))
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def getname(self):
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# Domain name unpacking (section 4.1.4)
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c = self.getbyte()
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i = ord(c)
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if i & 0xC0 == 0xC0:
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d = self.getbyte()
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j = ord(d)
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pointer = ((i<<8) | j) & ~0xC000
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save_offset = self.offset
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try:
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self.offset = pointer
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domain = self.getname()
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finally:
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self.offset = save_offset
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return domain
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if i == 0:
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return ''
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domain = self.getbytes(i)
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remains = self.getname()
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if not remains:
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return domain
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else:
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return domain + '.' + remains
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# Test program for packin/unpacking (section 4.1.4)
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def testpacker():
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N = 25
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R = range(N)
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import timing
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# See section 4.1.4 of RFC 1035
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timing.start()
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for i in R:
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p = Packer()
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p.addbytes('*' * 20)
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p.addname('f.ISI.ARPA')
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p.addbytes('*' * 8)
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p.addname('Foo.F.isi.arpa')
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p.addbytes('*' * 18)
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p.addname('arpa')
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p.addbytes('*' * 26)
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p.addname('')
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timing.finish()
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print round(timing.milli() * 0.001 / N, 3), 'seconds per packing'
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p.dump()
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u = Unpacker(p.buf)
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u.getbytes(20)
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u.getname()
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u.getbytes(8)
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u.getname()
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u.getbytes(18)
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u.getname()
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u.getbytes(26)
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u.getname()
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timing.start()
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for i in R:
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u = Unpacker(p.buf)
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res = (u.getbytes(20),
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u.getname(),
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u.getbytes(8),
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u.getname(),
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u.getbytes(18),
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u.getname(),
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u.getbytes(26),
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u.getname())
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timing.finish()
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print round(timing.milli() * 0.001 / N, 3), 'seconds per unpacking'
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for item in res: print item
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# Pack/unpack RR toplevel format (section 3.2.1)
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class RRpacker(Packer):
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def __init__(self):
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Packer.__init__(self)
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self.rdstart = None
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def addRRheader(self, name, type, klass, ttl, *rest):
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self.addname(name)
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self.add16bit(type)
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self.add16bit(klass)
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self.add32bit(ttl)
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if rest:
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if res[1:]: raise TypeError, 'too many args'
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rdlength = rest[0]
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else:
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rdlength = 0
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self.add16bit(rdlength)
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self.rdstart = len(self.buf)
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def patchrdlength(self):
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rdlength = unpack16bit(self.buf[self.rdstart-2:self.rdstart])
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if rdlength == len(self.buf) - self.rdstart:
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return
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rdata = self.buf[self.rdstart:]
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save_buf = self.buf
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ok = 0
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try:
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self.buf = self.buf[:self.rdstart-2]
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self.add16bit(len(rdata))
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self.buf = self.buf + rdata
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ok = 1
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finally:
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if not ok: self.buf = save_buf
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def endRR(self):
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if self.rdstart is not None:
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self.patchrdlength()
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self.rdstart = None
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def getbuf(self):
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if self.rdstart is not None: self.patchrdlenth()
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return Packer.getbuf(self)
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# Standard RRs (section 3.3)
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def addCNAME(self, name, klass, ttl, cname):
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self.addRRheader(name, DNS.Type.CNAME, klass, ttl)
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self.addname(cname)
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self.endRR()
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def addHINFO(self, name, klass, ttl, cpu, os):
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self.addRRheader(name, DNS.Type.HINFO, klass, ttl)
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self.addstring(cpu)
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self.addstring(os)
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self.endRR()
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def addMX(self, name, klass, ttl, preference, exchange):
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self.addRRheader(name, DNS.Type.MX, klass, ttl)
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self.add16bit(preference)
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self.addname(exchange)
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self.endRR()
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def addNS(self, name, klass, ttl, nsdname):
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self.addRRheader(name, DNS.Type.NS, klass, ttl)
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self.addname(nsdname)
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self.endRR()
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def addPTR(self, name, klass, ttl, ptrdname):
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self.addRRheader(name, DNS.Type.PTR, klass, ttl)
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self.addname(ptrdname)
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self.endRR()
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def addSOA(self, name, klass, ttl,
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mname, rname, serial, refresh, retry, expire, minimum):
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self.addRRheader(name, DNS.Type.SOA, klass, ttl)
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self.addname(mname)
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self.addname(rname)
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self.add32bit(serial)
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self.add32bit(refresh)
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self.add32bit(retry)
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self.add32bit(expire)
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self.add32bit(minimum)
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self.endRR()
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def addTXT(self, name, klass, ttl, list):
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self.addRRheader(name, DNS.Type.TXT, klass, ttl)
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for txtdata in list:
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self.addstring(txtdata)
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self.endRR()
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# Internet specific RRs (section 3.4) -- class = IN
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def addA(self, name, ttl, address):
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self.addRRheader(name, DNS.Type.A, DNS.Class.IN, ttl)
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self.addaddr(address)
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self.endRR()
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def addWKS(self, name, ttl, address, protocol, bitmap):
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self.addRRheader(name, DNS.Type.WKS, DNS.Class.IN, ttl)
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self.addaddr(address)
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self.addbyte(chr(protocol))
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self.addbytes(bitmap)
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self.endRR()
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def prettyTime(seconds):
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if seconds<60:
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return seconds,"%d seconds"%(seconds)
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if seconds<3600:
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return seconds,"%d minutes"%(seconds/60)
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if seconds<86400:
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return seconds,"%d hours"%(seconds/3600)
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if seconds<604800:
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return seconds,"%d days"%(seconds/86400)
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else:
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return seconds,"%d weeks"%(seconds/604800)
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class RRunpacker(Unpacker):
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def __init__(self, buf):
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Unpacker.__init__(self, buf)
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self.rdend = None
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def getRRheader(self):
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name = self.getname()
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type = self.get16bit()
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klass = self.get16bit()
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ttl = self.get32bit()
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rdlength = self.get16bit()
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self.rdend = self.offset + rdlength
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return (name, type, klass, ttl, rdlength)
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def endRR(self):
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if self.offset != self.rdend:
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raise UnpackError, 'end of RR not reached'
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def getCNAMEdata(self):
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return self.getname()
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def getHINFOdata(self):
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return self.getstring(), self.getstring()
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def getMXdata(self):
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return self.get16bit(), self.getname()
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def getNSdata(self):
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return self.getname()
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def getPTRdata(self):
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return self.getname()
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def getSOAdata(self):
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return self.getname(), \
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self.getname(), \
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('serial',)+(self.get32bit(),), \
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('refresh ',)+prettyTime(self.get32bit()), \
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('retry',)+prettyTime(self.get32bit()), \
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('expire',)+prettyTime(self.get32bit()), \
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('minimum',)+prettyTime(self.get32bit())
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def getTXTdata(self):
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list = []
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while self.offset != self.rdend:
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list.append(self.getstring())
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return list
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def getAdata(self):
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return self.getaddr()
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def getWKSdata(self):
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address = self.getaddr()
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protocol = ord(self.getbyte())
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bitmap = self.getbytes(self.rdend - self.offset)
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return address, protocol, bitmap
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# Pack/unpack Message Header (section 4.1)
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class Hpacker(Packer):
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def addHeader(self, id, qr, opcode, aa, tc, rd, ra, z, rcode,
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qdcount, ancount, nscount, arcount):
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self.add16bit(id)
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self.add16bit((qr&1)<<15 | (opcode*0xF)<<11 | (aa&1)<<10
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| (tc&1)<<9 | (rd&1)<<8 | (ra&1)<<7
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| (z&7)<<4 | (rcode&0xF))
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self.add16bit(qdcount)
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self.add16bit(ancount)
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self.add16bit(nscount)
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self.add16bit(arcount)
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class Hunpacker(Unpacker):
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def getHeader(self):
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id = self.get16bit()
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flags = self.get16bit()
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qr, opcode, aa, tc, rd, ra, z, rcode = (
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(flags>>15)&1,
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(flags>>11)&0xF,
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(flags>>10)&1,
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(flags>>9)&1,
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(flags>>8)&1,
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(flags>>7)&1,
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(flags>>4)&7,
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(flags>>0)&0xF)
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qdcount = self.get16bit()
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ancount = self.get16bit()
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nscount = self.get16bit()
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arcount = self.get16bit()
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return (id, qr, opcode, aa, tc, rd, ra, z, rcode,
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qdcount, ancount, nscount, arcount)
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# Pack/unpack Question (section 4.1.2)
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class Qpacker(Packer):
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def addQuestion(self, qname, qtype, qclass):
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self.addname(qname)
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self.add16bit(qtype)
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self.add16bit(qclass)
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class Qunpacker(Unpacker):
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def getQuestion(self):
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return self.getname(), self.get16bit(), self.get16bit()
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# Pack/unpack Message(section 4)
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# NB the order of the base classes is important for __init__()!
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class Mpacker(RRpacker, Qpacker, Hpacker):
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pass
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class Munpacker(RRunpacker, Qunpacker, Hunpacker):
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pass
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# Routines to print an unpacker to stdout, for debugging.
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# These affect the unpacker's current position!
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def dumpM(u):
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print 'HEADER:',
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(id, qr, opcode, aa, tc, rd, ra, z, rcode,
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qdcount, ancount, nscount, arcount) = u.getHeader()
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print 'id=%d,' % id,
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print 'qr=%d, opcode=%d, aa=%d, tc=%d, rd=%d, ra=%d, z=%d, rcode=%d,' \
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% (qr, opcode, aa, tc, rd, ra, z, rcode)
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if tc: print '*** response truncated! ***'
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if rcode: print '*** nonzero error code! (%d) ***' % rcode
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print ' qdcount=%d, ancount=%d, nscount=%d, arcount=%d' \
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% (qdcount, ancount, nscount, arcount)
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for i in range(qdcount):
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print 'QUESTION %d:' % i,
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dumpQ(u)
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for i in range(ancount):
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print 'ANSWER %d:' % i,
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dumpRR(u)
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for i in range(nscount):
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print 'AUTHORITY RECORD %d:' % i,
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dumpRR(u)
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for i in range(arcount):
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print 'ADDITIONAL RECORD %d:' % i,
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dumpRR(u)
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class DnsResult:
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def __init__(self,u,args):
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self.header={}
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self.questions=[]
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self.answers=[]
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self.authority=[]
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self.additional=[]
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self.args=args
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self.storeM(u)
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def show(self):
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import time
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print '; <<>> PDG.py 1.0 <<>> %s %s'%(self.args['name'],
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self.args['qtype'])
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opt=""
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if self.args['rd']:
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opt=opt+'recurs '
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h=self.header
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print ';; options: '+opt
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print ';; got answer:'
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print ';; ->>HEADER<<- opcode %s, status %s, id %d'%(
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h['opcode'],h['status'],h['id'])
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flags=filter(lambda x,h=h:h[x],('qr','aa','rd','ra','tc'))
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print ';; flags: %s; Ques: %d, Ans: %d, Auth: %d, Addit: %d'%(
|
|
' '.join(flags),h['qdcount'],h['ancount'],h['nscount'],
|
|
h['arcount'])
|
|
print ';; QUESTIONS:'
|
|
for q in self.questions:
|
|
print ';; %s, type = %s, class = %s'%(q['qname'],q['qtypestr'],
|
|
q['qclassstr'])
|
|
print
|
|
print ';; ANSWERS:'
|
|
for a in self.answers:
|
|
print '%-20s %-6s %-6s %s'%(a['name'],`a['ttl']`,a['typename'],
|
|
a['data'])
|
|
print
|
|
print ';; AUTHORITY RECORDS:'
|
|
for a in self.authority:
|
|
print '%-20s %-6s %-6s %s'%(a['name'],`a['ttl']`,a['typename'],
|
|
a['data'])
|
|
print
|
|
print ';; ADDITIONAL RECORDS:'
|
|
for a in self.additional:
|
|
print '%-20s %-6s %-6s %s'%(a['name'],`a['ttl']`,a['typename'],
|
|
a['data'])
|
|
print
|
|
if self.args.has_key('elapsed'):
|
|
print ';; Total query time: %d msec'%self.args['elapsed']
|
|
print ';; To SERVER: %s'%(self.args['server'])
|
|
print ';; WHEN: %s'%time.ctime(time.time())
|
|
|
|
def storeM(self,u):
|
|
(self.header['id'], self.header['qr'], self.header['opcode'],
|
|
self.header['aa'], self.header['tc'], self.header['rd'],
|
|
self.header['ra'], self.header['z'], self.header['rcode'],
|
|
self.header['qdcount'], self.header['ancount'],
|
|
self.header['nscount'], self.header['arcount']) = u.getHeader()
|
|
self.header['opcodestr']=DNS.Opcode.opcodestr(self.header['opcode'])
|
|
self.header['status']=DNS.Status.statusstr(self.header['rcode'])
|
|
for i in range(self.header['qdcount']):
|
|
#print 'QUESTION %d:' % i,
|
|
self.questions.append(self.storeQ(u))
|
|
for i in range(self.header['ancount']):
|
|
#print 'ANSWER %d:' % i,
|
|
self.answers.append(self.storeRR(u))
|
|
for i in range(self.header['nscount']):
|
|
#print 'AUTHORITY RECORD %d:' % i,
|
|
self.authority.append(self.storeRR(u))
|
|
for i in range(self.header['arcount']):
|
|
#print 'ADDITIONAL RECORD %d:' % i,
|
|
self.additional.append(self.storeRR(u))
|
|
|
|
def storeQ(self,u):
|
|
q={}
|
|
q['qname'], q['qtype'], q['qclass'] = u.getQuestion()
|
|
q['qtypestr']=DNS.Type.typestr(q['qtype'])
|
|
q['qclassstr']=DNS.Class.classstr(q['qclass'])
|
|
return q
|
|
|
|
def storeRR(self,u):
|
|
r={}
|
|
r['name'],r['type'],r['class'],r['ttl'],r['rdlength'] = u.getRRheader()
|
|
r['typename'] = DNS.Type.typestr(r['type'])
|
|
r['classstr'] = DNS.Class.classstr(r['class'])
|
|
#print 'name=%s, type=%d(%s), class=%d(%s), ttl=%d' \
|
|
# % (name,
|
|
# type, typename,
|
|
# klass, DNS.Class.classstr(class),
|
|
# ttl)
|
|
mname = 'get%sdata' % r['typename']
|
|
if hasattr(u, mname):
|
|
r['data']=getattr(u, mname)()
|
|
else:
|
|
r['data']=u.getbytes(r['rdlength'])
|
|
return r
|
|
|
|
def dumpQ(u):
|
|
qname, qtype, qclass = u.getQuestion()
|
|
print 'qname=%s, qtype=%d(%s), qclass=%d(%s)' \
|
|
% (qname,
|
|
qtype, DNS.Type.typestr(qtype),
|
|
qclass, DNS.Class.classstr(qclass))
|
|
|
|
def dumpRR(u):
|
|
name, type, klass, ttl, rdlength = u.getRRheader()
|
|
typename = DNS.Type.typestr(type)
|
|
print 'name=%s, type=%d(%s), class=%d(%s), ttl=%d' \
|
|
% (name,
|
|
type, typename,
|
|
klass, DNS.Class.classstr(klass),
|
|
ttl)
|
|
mname = 'get%sdata' % typename
|
|
if hasattr(u, mname):
|
|
print ' formatted rdata:', getattr(u, mname)()
|
|
else:
|
|
print ' binary rdata:', u.getbytes(rdlength)
|
|
|