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-rwxr-xr-xDemo/dns/dnslib.py588
1 files changed, 588 insertions, 0 deletions
diff --git a/Demo/dns/dnslib.py b/Demo/dns/dnslib.py
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+++ b/Demo/dns/dnslib.py
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+# Domain Name Server (DNS) interface
+#
+# See RFC 1035:
+# ------------------------------------------------------------------------
+# Network Working Group P. Mockapetris
+# Request for Comments: 1035 ISI
+# November 1987
+# Obsoletes: RFCs 882, 883, 973
+#
+# DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION
+# ------------------------------------------------------------------------
+
+
+import string
+
+import dnstype
+import dnsclass
+import dnsopcode
+
+
+# Low-level 16 and 32 bit integer packing and unpacking
+
+def pack16bit(n):
+ return chr((n>>8)&0xFF) + chr(n&0xFF)
+
+def pack32bit(n):
+ return chr((n>>24)&0xFF) + chr((n>>16)&0xFF) \
+ + chr((n>>8)&0xFF) + chr(n&0xFF)
+
+def unpack16bit(s):
+ return (ord(s[0])<<8) | ord(s[1])
+
+def unpack32bit(s):
+ return (ord(s[0])<<24) | (ord(s[1])<<16) \
+ | (ord(s[2])<<8) | ord(s[3])
+
+def addr2bin(addr):
+ if type(addr) == type(0):
+ return addr
+ bytes = string.splitfields(addr, '.')
+ if len(bytes) != 4: raise ValueError, 'bad IP address'
+ n = 0
+ for byte in bytes: n = n<<8 | string.atoi(byte)
+ return n
+
+def bin2addr(n):
+ return '%d.%d.%d.%d' % ((n>>24)&0xFF, (n>>16)&0xFF,
+ (n>>8)&0xFF, n&0xFF)
+
+
+# Packing class
+
+class Packer:
+ def __init__(self):
+ self.buf = ''
+ self.index = {}
+ def getbuf(self):
+ return self.buf
+ def addbyte(self, c):
+ if len(c) != 1: raise TypeError, 'one character expected'
+ self.buf = self.buf + c
+ def addbytes(self, bytes):
+ self.buf = self.buf + bytes
+ def add16bit(self, n):
+ self.buf = self.buf + pack16bit(n)
+ def add32bit(self, n):
+ self.buf = self.buf + pack32bit(n)
+ def addaddr(self, addr):
+ n = addr2bin(addr)
+ self.buf = self.buf + pack32bit(n)
+ def addstring(self, s):
+ self.addbyte(chr(len(s)))
+ self.addbytes(s)
+ def addname(self, name):
+ # Domain name packing (section 4.1.4)
+ # Add a domain name to the buffer, possibly using pointers.
+ # The case of the first occurrence of a name is preserved.
+ # Redundant dots are ignored.
+ list = []
+ for label in string.splitfields(name, '.'):
+ if label:
+ if len(label) > 63:
+ raise PackError, 'label too long'
+ list.append(label)
+ keys = []
+ for i in range(len(list)):
+ key = string.upper(string.joinfields(list[i:], '.'))
+ keys.append(key)
+ if self.index.has_key(key):
+ pointer = self.index[key]
+ break
+ else:
+ i = len(list)
+ pointer = None
+ # Do it into temporaries first so exceptions don't
+ # mess up self.index and self.buf
+ buf = ''
+ offset = len(self.buf)
+ index = []
+ for j in range(i):
+ label = list[j]
+ n = len(label)
+ if offset + len(buf) < 0x3FFF:
+ index.append(keys[j], offset + len(buf))
+ else:
+ print 'dnslib.Packer.addname:',
+ print 'warning: pointer too big'
+ buf = buf + (chr(n) + label)
+ if pointer:
+ buf = buf + pack16bit(pointer | 0xC000)
+ else:
+ buf = buf + '\0'
+ self.buf = self.buf + buf
+ for key, value in index:
+ self.index[key] = value
+ def dump(self):
+ keys = self.index.keys()
+ keys.sort()
+ print '-'*40
+ for key in keys:
+ print '%20s %3d' % (key, self.index[key])
+ print '-'*40
+ space = 1
+ for i in range(0, len(self.buf)+1, 2):
+ if self.buf[i:i+2] == '**':
+ if not space: print
+ space = 1
+ continue
+ space = 0
+ print '%4d' % i,
+ for c in self.buf[i:i+2]:
+ if ' ' < c < '\177':
+ print ' %c' % c,
+ else:
+ print '%2d' % ord(c),
+ print
+ print '-'*40
+
+
+# Unpacking class
+
+UnpackError = 'dnslib.UnpackError' # Exception
+
+class Unpacker:
+ def __init__(self, buf):
+ self.buf = buf
+ self.offset = 0
+ def getbyte(self):
+ c = self.buf[self.offset]
+ self.offset = self.offset + 1
+ return c
+ def getbytes(self, n):
+ s = self.buf[self.offset : self.offset + n]
+ if len(s) != n: raise UnpackError, 'not enough data left'
+ self.offset = self.offset + n
+ return s
+ def get16bit(self):
+ return unpack16bit(self.getbytes(2))
+ def get32bit(self):
+ return unpack32bit(self.getbytes(4))
+ def getaddr(self):
+ return bin2addr(self.get32bit())
+ def getstring(self):
+ return self.getbytes(ord(self.getbyte()))
+ def getname(self):
+ # Domain name unpacking (section 4.1.4)
+ c = self.getbyte()
+ i = ord(c)
+ if i & 0xC0 == 0xC0:
+ d = self.getbyte()
+ j = ord(d)
+ pointer = ((i<<8) | j) & ~0xC000
+ save_offset = self.offset
+ try:
+ self.offset = pointer
+ domain = self.getname()
+ finally:
+ self.offset = save_offset
+ return domain
+ if i == 0:
+ return ''
+ domain = self.getbytes(i)
+ remains = self.getname()
+ if not remains:
+ return domain
+ else:
+ return domain + '.' + remains
+
+
+# Test program for packin/unpacking (section 4.1.4)
+
+def testpacker():
+ N = 25
+ R = range(N)
+ import timing
+ # See section 4.1.4 of RFC 1035
+ timing.start()
+ for i in R:
+ p = Packer()
+ p.addbytes('*' * 20)
+ p.addname('f.ISI.ARPA')
+ p.addbytes('*' * 8)
+ p.addname('Foo.F.isi.arpa')
+ p.addbytes('*' * 18)
+ p.addname('arpa')
+ p.addbytes('*' * 26)
+ p.addname('')
+ timing.finish()
+ print round(timing.milli() * 0.001 / N, 3), 'seconds per packing'
+ p.dump()
+ u = Unpacker(p.buf)
+ u.getbytes(20)
+ u.getname()
+ u.getbytes(8)
+ u.getname()
+ u.getbytes(18)
+ u.getname()
+ u.getbytes(26)
+ u.getname()
+ timing.start()
+ for i in R:
+ u = Unpacker(p.buf)
+ res = (u.getbytes(20),
+ u.getname(),
+ u.getbytes(8),
+ u.getname(),
+ u.getbytes(18),
+ u.getname(),
+ u.getbytes(26),
+ u.getname())
+ timing.finish()
+ print round(timing.milli() * 0.001 / N, 3), 'seconds per unpacking'
+ for item in res: print item
+
+
+# Pack/unpack RR toplevel format (section 3.2.1)
+
+class RRpacker(Packer):
+ def __init__(self):
+ Packer.__init__(self)
+ self.rdstart = None
+ def addRRheader(self, name, type, klass, ttl, *rest):
+ self.addname(name)
+ self.add16bit(type)
+ self.add16bit(klass)
+ self.add32bit(ttl)
+ if rest:
+ if res[1:]: raise TypeError, 'too many args'
+ rdlength = rest[0]
+ else:
+ rdlength = 0
+ self.add16bit(rdlength)
+ self.rdstart = len(self.buf)
+ def patchrdlength(self):
+ rdlength = unpack16bit(self.buf[self.rdstart-2:self.rdstart])
+ if rdlength == len(self.buf) - self.rdstart:
+ return
+ rdata = self.buf[self.rdstart:]
+ save_buf = self.buf
+ ok = 0
+ try:
+ self.buf = self.buf[:self.rdstart-2]
+ self.add16bit(len(rdata))
+ self.buf = self.buf + rdata
+ ok = 1
+ finally:
+ if not ok: self.buf = save_buf
+ def endRR(self):
+ if self.rdstart is not None:
+ self.patchrdlength()
+ self.rdstart = None
+ def getbuf(self):
+ if self.rdstart is not None: self.patchrdlenth()
+ return Packer.getbuf(self)
+ # Standard RRs (section 3.3)
+ def addCNAME(self, name, klass, ttl, cname):
+ self.addRRheader(name, dnstype.CNAME, klass, ttl)
+ self.addname(cname)
+ self.endRR()
+ def addHINFO(self, name, klass, ttl, cpu, os):
+ self.addRRheader(name, dnstype.HINFO, klass, ttl)
+ self.addstring(cpu)
+ self.addstring(os)
+ self.endRR()
+ def addMX(self, name, klass, ttl, preference, exchange):
+ self.addRRheader(name, dnstype.MX, klass, ttl)
+ self.add16bit(preference)
+ self.addname(exchange)
+ self.endRR()
+ def addNS(self, name, klass, ttl, nsdname):
+ self.addRRheader(name, dnstype.NS, klass, ttl)
+ self.addname(nsdname)
+ self.endRR()
+ def addPTR(self, name, klass, ttl, ptrdname):
+ self.addRRheader(name, dnstype.PTR, klass, ttl)
+ self.addname(ptrdname)
+ self.endRR()
+ def addSOA(self, name, klass, ttl,
+ mname, rname, serial, refresh, retry, expire, minimum):
+ self.addRRheader(name, dnstype.SOA, klass, ttl)
+ self.addname(mname)
+ self.addname(rname)
+ self.add32bit(serial)
+ self.add32bit(refresh)
+ self.add32bit(retry)
+ self.add32bit(expire)
+ self.add32bit(minimum)
+ self.endRR()
+ def addTXT(self, name, klass, ttl, list):
+ self.addRRheader(name, dnstype.TXT, klass, ttl)
+ for txtdata in list:
+ self.addstring(txtdata)
+ self.endRR()
+ # Internet specific RRs (section 3.4) -- class = IN
+ def addA(self, name, ttl, address):
+ self.addRRheader(name, dnstype.A, dnsclass.IN, ttl)
+ self.addaddr(address)
+ self.endRR()
+ def addWKS(self, name, ttl, address, protocol, bitmap):
+ self.addRRheader(name, dnstype.WKS, dnsclass.IN, ttl)
+ self.addaddr(address)
+ self.addbyte(chr(protocol))
+ self.addbytes(bitmap)
+ self.endRR()
+
+
+class RRunpacker(Unpacker):
+ def __init__(self, buf):
+ Unpacker.__init__(self, buf)
+ self.rdend = None
+ def getRRheader(self):
+ name = self.getname()
+ type = self.get16bit()
+ klass = self.get16bit()
+ ttl = self.get32bit()
+ rdlength = self.get16bit()
+ self.rdend = self.offset + rdlength
+ return (name, type, klass, ttl, rdlength)
+ def endRR(self):
+ if self.offset != self.rdend:
+ raise UnpackError, 'end of RR not reached'
+ def getCNAMEdata(self):
+ return self.getname()
+ def getHINFOdata(self):
+ return self.getstring(), self.getstring()
+ def getMXdata(self):
+ return self.get16bit(), self.getname()
+ def getNSdata(self):
+ return self.getname()
+ def getPTRdata(self):
+ return self.getname()
+ def getSOAdata(self):
+ return self.getname(), \
+ self.getname(), \
+ self.get32bit(), \
+ self.get32bit(), \
+ self.get32bit(), \
+ self.get32bit(), \
+ self.get32bit()
+ def getTXTdata(self):
+ list = []
+ while self.offset != self.rdend:
+ list.append(self.getstring())
+ return list
+ def getAdata(self):
+ return self.getaddr()
+ def getWKSdata(self):
+ address = self.getaddr()
+ protocol = ord(self.getbyte())
+ bitmap = self.getbytes(self.rdend - self.offset)
+ return address, protocol, bitmap
+
+
+# Pack/unpack Message Header (section 4.1)
+
+class Hpacker(Packer):
+ def addHeader(self, id, qr, opcode, aa, tc, rd, ra, z, rcode,
+ qdcount, ancount, nscount, arcount):
+ self.add16bit(id)
+ self.add16bit((qr&1)<<15 | (opcode*0xF)<<11 | (aa&1)<<10
+ | (tc&1)<<9 | (rd&1)<<8 | (ra&1)<<7
+ | (z&7)<<4 | (rcode&0xF))
+ self.add16bit(qdcount)
+ self.add16bit(ancount)
+ self.add16bit(nscount)
+ self.add16bit(arcount)
+
+class Hunpacker(Unpacker):
+ def getHeader(self):
+ id = self.get16bit()
+ flags = self.get16bit()
+ qr, opcode, aa, tc, rd, ra, z, rcode = (
+ (flags>>15)&1,
+ (flags>>11)&0xF,
+ (flags>>10)&1,
+ (flags>>9)&1,
+ (flags>>8)&1,
+ (flags>>7)&1,
+ (flags>>4)&7,
+ (flags>>0)&0xF)
+ qdcount = self.get16bit()
+ ancount = self.get16bit()
+ nscount = self.get16bit()
+ arcount = self.get16bit()
+ return (id, qr, opcode, aa, tc, rd, ra, z, rcode,
+ qdcount, ancount, nscount, arcount)
+
+
+# Pack/unpack Question (section 4.1.2)
+
+class Qpacker(Packer):
+ def addQuestion(self, qname, qtype, qclass):
+ self.addname(qname)
+ self.add16bit(qtype)
+ self.add16bit(qclass)
+
+class Qunpacker(Unpacker):
+ def getQuestion(self):
+ return self.getname(), self.get16bit(), self.get16bit()
+
+
+# Pack/unpack Message(section 4)
+# NB the order of the base classes is important for __init__()!
+
+class Mpacker(RRpacker, Qpacker, Hpacker):
+ pass
+
+class Munpacker(RRunpacker, Qunpacker, Hunpacker):
+ pass
+
+
+# Routines to print an unpacker to stdout, for debugging.
+# These affect the unpacker's current position!
+
+def dumpM(u):
+ print 'HEADER:',
+ (id, qr, opcode, aa, tc, rd, ra, z, rcode,
+ qdcount, ancount, nscount, arcount) = u.getHeader()
+ print 'id=%d,' % id,
+ print 'qr=%d, opcode=%d, aa=%d, tc=%d, rd=%d, ra=%d, z=%d, rcode=%d,' \
+ % (qr, opcode, aa, tc, rd, ra, z, rcode)
+ if tc: print '*** response truncated! ***'
+ if rcode: print '*** nonzero error code! (%d) ***' % rcode
+ print ' qdcount=%d, ancount=%d, nscount=%d, arcount=%d' \
+ % (qdcount, ancount, nscount, arcount)
+ for i in range(qdcount):
+ print 'QUESTION %d:' % i,
+ dumpQ(u)
+ for i in range(ancount):
+ print 'ANSWER %d:' % i,
+ dumpRR(u)
+ for i in range(nscount):
+ print 'AUTHORITY RECORD %d:' % i,
+ dumpRR(u)
+ for i in range(arcount):
+ print 'ADDITIONAL RECORD %d:' % i,
+ dumpRR(u)
+
+def dumpQ(u):
+ qname, qtype, qclass = u.getQuestion()
+ print 'qname=%s, qtype=%d(%s), qclass=%d(%s)' \
+ % (qname,
+ qtype, dnstype.typestr(qtype),
+ qclass, dnsclass.classstr(qclass))
+
+def dumpRR(u):
+ name, type, klass, ttl, rdlength = u.getRRheader()
+ typename = dnstype.typestr(type)
+ print 'name=%s, type=%d(%s), class=%d(%s), ttl=%d' \
+ % (name,
+ type, typename,
+ klass, dnsclass.classstr(klass),
+ ttl)
+ mname = 'get%sdata' % typename
+ if hasattr(u, mname):
+ print ' formatted rdata:', getattr(u, mname)()
+ else:
+ print ' binary rdata:', u.getbytes(rdlength)
+
+
+# Test program
+
+def test():
+ import sys
+ import getopt
+ import socket
+ protocol = 'udp'
+ server = 'meermin.cwi.nl' # XXX adapt this to your local
+ port = 53
+ opcode = dnsopcode.QUERY
+ rd = 0
+ qtype = dnstype.MX
+ qname = 'cwi.nl'
+ try:
+ opts, args = getopt.getopt(sys.argv[1:], 'Trs:tu')
+ if len(args) > 2: raise getopt.error, 'too many arguments'
+ except getopt.error, msg:
+ print msg
+ print 'Usage: python dnslib.py',
+ print '[-T] [-r] [-s server] [-t] [-u]',
+ print '[qtype [qname]]'
+ print '-T: run testpacker() and exit'
+ print '-r: recursion desired (default not)'
+ print '-s server: use server (default %s)' % server
+ print '-t: use TCP protocol'
+ print '-u: use UDP protocol (default)'
+ print 'qtype: query type (default %s)' % \
+ dnstype.typestr(qtype)
+ print 'qname: query name (default %s)' % qname
+ print 'Recognized qtype values:'
+ qtypes = dnstype.typemap.keys()
+ qtypes.sort()
+ n = 0
+ for qtype in qtypes:
+ n = n+1
+ if n >= 8: n = 1; print
+ print '%s = %d' % (dnstype.typemap[qtype], qtype),
+ print
+ sys.exit(2)
+ for o, a in opts:
+ if o == '-T': testpacker(); return
+ if o == '-t': protocol = 'tcp'
+ if o == '-u': protocol = 'udp'
+ if o == '-s': server = a
+ if o == '-r': rd = 1
+ if args[0:]:
+ try:
+ qtype = eval(string.upper(args[0]), dnstype.__dict__)
+ except (NameError, SyntaxError):
+ print 'bad query type:', `args[0]`
+ sys.exit(2)
+ if args[1:]:
+ qname = args[1]
+ if qtype == dnstype.AXFR:
+ print 'Query type AXFR, protocol forced to TCP'
+ protocol = 'tcp'
+ print 'QTYPE %d(%s)' % (qtype, dnstype.typestr(qtype))
+ m = Mpacker()
+ m.addHeader(0,
+ 0, opcode, 0, 0, rd, 0, 0, 0,
+ 1, 0, 0, 0)
+ m.addQuestion(qname, qtype, dnsclass.IN)
+ request = m.getbuf()
+ if protocol == 'udp':
+ s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+ s.connect((server, port))
+ s.send(request)
+ reply = s.recv(1024)
+ else:
+ s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+ s.connect((server, port))
+ s.send(pack16bit(len(request)) + request)
+ s.shutdown(1)
+ f = s.makefile('r')
+ header = f.read(2)
+ if len(header) < 2:
+ print '*** EOF ***'
+ return
+ count = unpack16bit(header)
+ reply = f.read(count)
+ if len(reply) != count:
+ print '*** Incomplete reply ***'
+ return
+ u = Munpacker(reply)
+ dumpM(u)
+ if protocol == 'tcp' and qtype == dnstype.AXFR:
+ while 1:
+ header = f.read(2)
+ if len(header) < 2:
+ print '========== EOF =========='
+ break
+ count = unpack16bit(header)
+ if not count:
+ print '========== ZERO COUNT =========='
+ break
+ print '========== NEXT =========='
+ reply = f.read(count)
+ if len(reply) != count:
+ print '*** Incomplete reply ***'
+ break
+ u = Munpacker(reply)
+ dumpM(u)
+
+
+# Run test program when called as a script
+
+if __name__ == '__main__':
+ test()
generated by cgit v0.12 at 2024-12-29 11:25:48 (GMT)