/usr/lib/python2.7/dist-packages/scapy/layers/dns.py is in python-scapy 2.3.3-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 | ## This file is part of Scapy
## See http://www.secdev.org/projects/scapy for more informations
## Copyright (C) Philippe Biondi <phil@secdev.org>
## This program is published under a GPLv2 license
"""
DNS: Domain Name System.
"""
import socket,struct
from scapy.config import conf
from scapy.packet import *
from scapy.fields import *
from scapy.ansmachine import *
from scapy.sendrecv import sr1
from scapy.layers.inet import IP, DestIPField, UDP
from scapy.layers.inet6 import DestIP6Field
class DNSStrField(StrField):
def h2i(self, pkt, x):
if x == "":
return "."
return x
def i2m(self, pkt, x):
if x == ".":
return "\x00"
x = [k[:63] for k in x.split(".")] # Truncate chunks that cannot be encoded (more than 63 bytes..)
x = map(lambda y: chr(len(y))+y, x)
x = "".join(x)
if x[-1] != "\x00":
x += "\x00"
return x
def getfield(self, pkt, s):
n = ""
if ord(s[0]) == 0:
return s[1:], "."
while 1:
l = ord(s[0])
s = s[1:]
if not l:
break
if l & 0xc0:
raise Scapy_Exception("DNS message can't be compressed at this point!")
else:
n += s[:l]+"."
s = s[l:]
return s, n
class DNSRRCountField(ShortField):
__slots__ = ["rr"]
def __init__(self, name, default, rr):
ShortField.__init__(self, name, default)
self.rr = rr
def _countRR(self, pkt):
x = getattr(pkt,self.rr)
i = 0
while isinstance(x, DNSRR) or isinstance(x, DNSQR) or isdnssecRR(x):
x = x.payload
i += 1
return i
def i2m(self, pkt, x):
if x is None:
x = self._countRR(pkt)
return x
def i2h(self, pkt, x):
if x is None:
x = self._countRR(pkt)
return x
def DNSgetstr(s,p):
name = ""
q = 0
jpath = [p]
while 1:
if p >= len(s):
warning("DNS RR prematured end (ofs=%i, len=%i)"%(p,len(s)))
break
l = ord(s[p])
p += 1
if l & 0xc0:
if not q:
q = p+1
if p >= len(s):
warning("DNS incomplete jump token at (ofs=%i)" % p)
break
p = ((l & 0x3f) << 8) + ord(s[p]) - 12
if p in jpath:
warning("DNS decompression loop detected")
break
jpath.append(p)
continue
elif l > 0:
name += s[p:p+l]+"."
p += l
continue
break
if q:
p = q
return name,p
class DNSRRField(StrField):
__slots__ = ["countfld", "passon"]
holds_packets = 1
def __init__(self, name, countfld, passon=1):
StrField.__init__(self, name, None)
self.countfld = countfld
self.passon = passon
def i2m(self, pkt, x):
if x is None:
return ""
return str(x)
def decodeRR(self, name, s, p):
ret = s[p:p+10]
type,cls,ttl,rdlen = struct.unpack("!HHIH", ret)
p += 10
rr = DNSRR("\x00"+ret+s[p:p+rdlen])
if type in [2, 3, 4, 5]:
rr.rdata = DNSgetstr(s,p)[0]
del(rr.rdlen)
elif type in DNSRR_DISPATCHER:
rr = DNSRR_DISPATCHER[type]("\x00"+ret+s[p:p+rdlen])
else:
del(rr.rdlen)
p += rdlen
rr.rrname = name
return rr,p
def getfield(self, pkt, s):
if type(s) is tuple :
s,p = s
else:
p = 0
ret = None
c = getattr(pkt, self.countfld)
if c > len(s):
warning("wrong value: DNS.%s=%i" % (self.countfld,c))
return s,""
while c:
c -= 1
name,p = DNSgetstr(s,p)
rr,p = self.decodeRR(name, s, p)
if ret is None:
ret = rr
else:
ret.add_payload(rr)
if self.passon:
return (s,p),ret
else:
return s[p:],ret
class DNSQRField(DNSRRField):
def decodeRR(self, name, s, p):
ret = s[p:p+4]
p += 4
rr = DNSQR("\x00"+ret)
rr.qname = name
return rr,p
class RDataField(StrLenField):
def m2i(self, pkt, s):
family = None
if pkt.type == 1: # A
family = socket.AF_INET
elif pkt.type == 12: # PTR
s = DNSgetstr(s, 0)[0]
elif pkt.type == 16: # TXT
ret_s = ""
tmp_s = s
# RDATA contains a list of strings, each are prepended with
# a byte containing the size of the following string.
while tmp_s:
tmp_len = struct.unpack("!B", tmp_s[0])[0] + 1
if tmp_len > len(tmp_s):
warning("DNS RR TXT prematured end of character-string (size=%i, remaining bytes=%i)" % (tmp_len, len(tmp_s)))
ret_s += tmp_s[1:tmp_len]
tmp_s = tmp_s[tmp_len:]
s = ret_s
elif pkt.type == 28: # AAAA
family = socket.AF_INET6
if family is not None:
s = inet_ntop(family, s)
return s
def i2m(self, pkt, s):
if pkt.type == 1: # A
if s:
s = inet_aton(s)
elif pkt.type in [2, 3, 4, 5, 12]: # NS, MD, MF, CNAME, PTR
s = "".join(map(lambda x: chr(len(x))+x, s.split(".")))
if ord(s[-1]):
s += "\x00"
elif pkt.type == 16: # TXT
if s:
ret_s = ""
# The initial string must be splitted into a list of strings
# prepended with theirs sizes.
while len(s) >= 255:
ret_s += "\xff" + s[:255]
s = s[255:]
# The remaining string is less than 255 bytes long
if len(s):
ret_s += struct.pack("!B", len(s)) + s
s = ret_s
elif pkt.type == 28: # AAAA
if s:
s = inet_pton(socket.AF_INET6, s)
return s
class RDLenField(Field):
def __init__(self, name):
Field.__init__(self, name, None, "H")
def i2m(self, pkt, x):
if x is None:
rdataf = pkt.get_field("rdata")
x = len(rdataf.i2m(pkt, pkt.rdata))
return x
def i2h(self, pkt, x):
if x is None:
rdataf = pkt.get_field("rdata")
x = len(rdataf.i2m(pkt, pkt.rdata))
return x
class DNS(Packet):
name = "DNS"
fields_desc = [ ShortField("id", 0),
BitField("qr", 0, 1),
BitEnumField("opcode", 0, 4, {0:"QUERY",1:"IQUERY",2:"STATUS"}),
BitField("aa", 0, 1),
BitField("tc", 0, 1),
BitField("rd", 1, 1),
BitField("ra", 0, 1),
BitField("z", 0, 1),
# AD and CD bits are defined in RFC 2535
BitField("ad", 0, 1), # Authentic Data
BitField("cd", 0, 1), # Checking Disabled
BitEnumField("rcode", 0, 4, {0:"ok", 1:"format-error", 2:"server-failure", 3:"name-error", 4:"not-implemented", 5:"refused"}),
DNSRRCountField("qdcount", None, "qd"),
DNSRRCountField("ancount", None, "an"),
DNSRRCountField("nscount", None, "ns"),
DNSRRCountField("arcount", None, "ar"),
DNSQRField("qd", "qdcount"),
DNSRRField("an", "ancount"),
DNSRRField("ns", "nscount"),
DNSRRField("ar", "arcount",0) ]
def answers(self, other):
return (isinstance(other, DNS)
and self.id == other.id
and self.qr == 1
and other.qr == 0)
def mysummary(self):
type = ["Qry","Ans"][self.qr]
name = ""
if self.qr:
type = "Ans"
if self.ancount > 0 and isinstance(self.an, DNSRR):
name = ' "%s"' % self.an.rdata
else:
type = "Qry"
if self.qdcount > 0 and isinstance(self.qd, DNSQR):
name = ' "%s"' % self.qd.qname
return 'DNS %s%s ' % (type, name)
dnstypes = { 0:"ANY", 255:"ALL",
1:"A", 2:"NS", 3:"MD", 4:"MF", 5:"CNAME", 6:"SOA", 7: "MB", 8:"MG",
9:"MR",10:"NULL",11:"WKS",12:"PTR",13:"HINFO",14:"MINFO",15:"MX",16:"TXT",
17:"RP",18:"AFSDB",28:"AAAA", 33:"SRV",38:"A6",39:"DNAME",
41:"OPT", 43:"DS", 46:"RRSIG", 47:"NSEC", 48:"DNSKEY",
50: "NSEC3", 51: "NSEC3PARAM", 32769:"DLV" }
dnsqtypes = {251:"IXFR",252:"AXFR",253:"MAILB",254:"MAILA",255:"ALL"}
dnsqtypes.update(dnstypes)
dnsclasses = {1: 'IN', 2: 'CS', 3: 'CH', 4: 'HS', 255: 'ANY'}
class DNSQR(Packet):
name = "DNS Question Record"
show_indent=0
fields_desc = [DNSStrField("qname", "www.example.com"),
ShortEnumField("qtype", 1, dnsqtypes),
ShortEnumField("qclass", 1, dnsclasses)]
# RFC 2671 - Extension Mechanisms for DNS (EDNS0)
class EDNS0TLV(Packet):
name = "DNS EDNS0 TLV"
fields_desc = [ ShortEnumField("optcode", 0, { 0: "Reserved", 1: "LLQ", 2: "UL", 3: "NSID", 4: "Reserved", 5: "PING" }),
FieldLenField("optlen", None, "optdata", fmt="H"),
StrLenField("optdata", "", length_from=lambda pkt: pkt.optlen) ]
def extract_padding(self, p):
return "", p
class DNSRROPT(Packet):
name = "DNS OPT Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 41, dnstypes),
ShortField("rclass", 4096),
ByteField("extrcode", 0),
ByteField("version", 0),
# version 0 means EDNS0
BitEnumField("z", 32768, 16, { 32768: "D0" }),
# D0 means DNSSEC OK from RFC 3225
FieldLenField("rdlen", None, length_of="rdata", fmt="H"),
PacketListField("rdata", [], EDNS0TLV, length_from=lambda pkt: pkt.rdlen) ]
# RFC 4034 - Resource Records for the DNS Security Extensions
# 09/2013 from http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml
dnssecalgotypes = { 0:"Reserved", 1:"RSA/MD5", 2:"Diffie-Hellman", 3:"DSA/SHA-1",
4:"Reserved", 5:"RSA/SHA-1", 6:"DSA-NSEC3-SHA1",
7:"RSASHA1-NSEC3-SHA1", 8:"RSA/SHA-256", 9:"Reserved",
10:"RSA/SHA-512", 11:"Reserved", 12:"GOST R 34.10-2001",
13:"ECDSA Curve P-256 with SHA-256", 14: "ECDSA Curve P-384 with SHA-384",
252:"Reserved for Indirect Keys", 253:"Private algorithms - domain name",
254:"Private algorithms - OID", 255:"Reserved" }
# 09/2013 from http://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml
dnssecdigesttypes = { 0:"Reserved", 1:"SHA-1", 2:"SHA-256", 3:"GOST R 34.11-94", 4:"SHA-384" }
class TimeField(IntField):
def any2i(self, pkt, x):
if type(x) == str:
import time, calendar
t = time.strptime(x, "%Y%m%d%H%M%S")
return int(calendar.timegm(t))
return x
def i2repr(self, pkt, x):
import time
x = self.i2h(pkt, x)
t = time.strftime("%Y%m%d%H%M%S", time.gmtime(x))
return "%s (%d)" % (t ,x)
def bitmap2RRlist(bitmap):
"""
Decode the 'Type Bit Maps' field of the NSEC Resource Record into an
integer list.
"""
# RFC 4034, 4.1.2. The Type Bit Maps Field
RRlist = []
while bitmap:
if len(bitmap) < 2:
warning("bitmap too short (%i)" % len(bitmap))
return
window_block = ord(bitmap[0]) # window number
offset = 256*window_block # offset of the Ressource Record
bitmap_len = ord(bitmap[1]) # length of the bitmap in bytes
if bitmap_len <= 0 or bitmap_len > 32:
warning("bitmap length is no valid (%i)" % bitmap_len)
return
tmp_bitmap = bitmap[2:2+bitmap_len]
# Let's compare each bit of tmp_bitmap and compute the real RR value
for b in xrange(len(tmp_bitmap)):
v = 128
for i in xrange(8):
if ord(tmp_bitmap[b]) & v:
# each of the RR is encoded as a bit
RRlist += [ offset + b*8 + i ]
v = v >> 1
# Next block if any
bitmap = bitmap[2+bitmap_len:]
return RRlist
def RRlist2bitmap(lst):
"""
Encode a list of integers representing Resource Records to a bitmap field
used in the NSEC Resource Record.
"""
# RFC 4034, 4.1.2. The Type Bit Maps Field
import math
bitmap = ""
lst = list(set(lst))
lst.sort()
lst = filter(lambda x: x <= 65535, lst)
lst = map(lambda x: abs(x), lst)
# number of window blocks
max_window_blocks = int(math.ceil(lst[-1] / 256.))
min_window_blocks = int(math.floor(lst[0] / 256.))
if min_window_blocks == max_window_blocks:
max_window_blocks += 1
for wb in xrange(min_window_blocks, max_window_blocks+1):
# First, filter out RR not encoded in the current window block
# i.e. keep everything between 256*wb <= 256*(wb+1)
rrlist = filter(lambda x: 256 * wb <= x < 256 * (wb + 1), lst)
rrlist.sort()
if rrlist == []:
continue
# Compute the number of bytes used to store the bitmap
if rrlist[-1] == 0: # only one element in the list
bytes = 1
else:
max = rrlist[-1] - 256*wb
bytes = int(math.ceil(max / 8)) + 1 # use at least 1 byte
if bytes > 32: # Don't encode more than 256 bits / values
bytes = 32
bitmap += struct.pack("B", wb)
bitmap += struct.pack("B", bytes)
# Generate the bitmap
for tmp in xrange(bytes):
v = 0
# Remove out of range Ressource Records
tmp_rrlist = filter(lambda x: 256 * wb + 8 * tmp <= x < 256 * wb + 8 * tmp + 8, rrlist)
if not tmp_rrlist == []:
# 1. rescale to fit into 8 bits
tmp_rrlist = map(lambda x: (x-256*wb)-(tmp*8), tmp_rrlist)
# 2. x gives the bit position ; compute the corresponding value
tmp_rrlist = map(lambda x: 2**(7-x) , tmp_rrlist)
# 3. sum everything
v = reduce(lambda x,y: x+y, tmp_rrlist)
bitmap += struct.pack("B", v)
return bitmap
class RRlistField(StrField):
def h2i(self, pkt, x):
if type(x) == list:
return RRlist2bitmap(x)
return x
def i2repr(self, pkt, x):
x = self.i2h(pkt, x)
rrlist = bitmap2RRlist(x)
return [ dnstypes.get(rr, rr) for rr in rrlist ]
class _DNSRRdummy(Packet):
name = "Dummy class that implements post_build() for Ressource Records"
def post_build(self, pkt, pay):
if not self.rdlen == None:
return pkt
lrrname = len(self.fields_desc[0].i2m("", self.getfieldval("rrname")))
l = len(pkt) - lrrname - 10
pkt = pkt[:lrrname+8] + struct.pack("!H", l) + pkt[lrrname+8+2:]
return pkt
class DNSRRSOA(_DNSRRdummy):
name = "DNS SOA Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 6, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
DNSStrField("mname", ""),
DNSStrField("rname", ""),
IntField("serial", 0),
IntField("refresh", 0),
IntField("retry", 0),
IntField("expire", 0),
IntField("minimum", 0)
]
class DNSRRRSIG(_DNSRRdummy):
name = "DNS RRSIG Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 46, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
ShortEnumField("typecovered", 1, dnstypes),
ByteEnumField("algorithm", 5, dnssecalgotypes),
ByteField("labels", 0),
IntField("originalttl", 0),
TimeField("expiration", 0),
TimeField("inception", 0),
ShortField("keytag", 0),
DNSStrField("signersname", ""),
StrField("signature", "")
]
class DNSRRNSEC(_DNSRRdummy):
name = "DNS NSEC Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 47, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
DNSStrField("nextname", ""),
RRlistField("typebitmaps", "")
]
class DNSRRDNSKEY(_DNSRRdummy):
name = "DNS DNSKEY Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 48, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
FlagsField("flags", 256, 16, "S???????Z???????"),
# S: Secure Entry Point
# Z: Zone Key
ByteField("protocol", 3),
ByteEnumField("algorithm", 5, dnssecalgotypes),
StrField("publickey", "")
]
class DNSRRDS(_DNSRRdummy):
name = "DNS DS Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 43, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
ShortField("keytag", 0),
ByteEnumField("algorithm", 5, dnssecalgotypes),
ByteEnumField("digesttype", 5, dnssecdigesttypes),
StrField("digest", "")
]
# RFC 5074 - DNSSEC Lookaside Validation (DLV)
class DNSRRDLV(DNSRRDS):
name = "DNS DLV Resource Record"
def __init__(self, *args, **kargs):
DNSRRDS.__init__(self, *args, **kargs)
if not kargs.get('type', 0):
self.type = 32769
# RFC 5155 - DNS Security (DNSSEC) Hashed Authenticated Denial of Existence
class DNSRRNSEC3(_DNSRRdummy):
name = "DNS NSEC3 Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 50, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
ByteField("hashalg", 0),
BitEnumField("flags", 0, 8, {1:"Opt-Out"}),
ShortField("iterations", 0),
FieldLenField("saltlength", 0, fmt="!B", length_of="salt"),
StrLenField("salt", "", length_from=lambda x: x.saltlength),
FieldLenField("hashlength", 0, fmt="!B", length_of="nexthashedownername"),
StrLenField("nexthashedownername", "", length_from=lambda x: x.hashlength),
RRlistField("typebitmaps", "")
]
class DNSRRNSEC3PARAM(_DNSRRdummy):
name = "DNS NSEC3PARAM Resource Record"
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 51, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
ShortField("rdlen", None),
ByteField("hashalg", 0),
ByteField("flags", 0),
ShortField("iterations", 0),
FieldLenField("saltlength", 0, fmt="!B", length_of="salt"),
StrLenField("salt", "", length_from=lambda pkt: pkt.saltlength)
]
DNSRR_DISPATCHER = {
41: DNSRROPT, # RFC 1671
43: DNSRRDS, # RFC 4034
46: DNSRRRSIG, # RFC 4034
47: DNSRRNSEC, # RFC 4034
48: DNSRRDNSKEY, # RFC 4034
50: DNSRRNSEC3, # RFC 5155
51: DNSRRNSEC3PARAM, # RFC 5155
32769: DNSRRDLV, # RFC 4431
}
DNSSEC_CLASSES = tuple(DNSRR_DISPATCHER.itervalues())
def isdnssecRR(obj):
return isinstance(obj, DNSSEC_CLASSES)
class DNSRR(Packet):
name = "DNS Resource Record"
show_indent=0
fields_desc = [ DNSStrField("rrname",""),
ShortEnumField("type", 1, dnstypes),
ShortEnumField("rclass", 1, dnsclasses),
IntField("ttl", 0),
RDLenField("rdlen"),
RDataField("rdata", "", length_from=lambda pkt:pkt.rdlen) ]
bind_layers(UDP, DNS, dport=5353)
bind_layers(UDP, DNS, sport=5353)
bind_layers(UDP, DNS, dport=53)
bind_layers(UDP, DNS, sport=53)
DestIPField.bind_addr(UDP, "224.0.0.251", dport=5353)
DestIP6Field.bind_addr(UDP, "ff02::fb", dport=5353)
@conf.commands.register
def dyndns_add(nameserver, name, rdata, type="A", ttl=10):
"""Send a DNS add message to a nameserver for "name" to have a new "rdata"
dyndns_add(nameserver, name, rdata, type="A", ttl=10) -> result code (0=ok)
example: dyndns_add("ns1.toto.com", "dyn.toto.com", "127.0.0.1")
RFC2136
"""
zone = name[name.find(".")+1:]
r=sr1(IP(dst=nameserver)/UDP()/DNS(opcode=5,
qd=[DNSQR(qname=zone, qtype="SOA")],
ns=[DNSRR(rrname=name, type="A",
ttl=ttl, rdata=rdata)]),
verbose=0, timeout=5)
if r and r.haslayer(DNS):
return r.getlayer(DNS).rcode
else:
return -1
@conf.commands.register
def dyndns_del(nameserver, name, type="ALL", ttl=10):
"""Send a DNS delete message to a nameserver for "name"
dyndns_del(nameserver, name, type="ANY", ttl=10) -> result code (0=ok)
example: dyndns_del("ns1.toto.com", "dyn.toto.com")
RFC2136
"""
zone = name[name.find(".")+1:]
r=sr1(IP(dst=nameserver)/UDP()/DNS(opcode=5,
qd=[DNSQR(qname=zone, qtype="SOA")],
ns=[DNSRR(rrname=name, type=type,
rclass="ANY", ttl=0, rdata="")]),
verbose=0, timeout=5)
if r and r.haslayer(DNS):
return r.getlayer(DNS).rcode
else:
return -1
class DNS_am(AnsweringMachine):
function_name="dns_spoof"
filter = "udp port 53"
def parse_options(self, joker="192.168.1.1", match=None):
if match is None:
self.match = {}
else:
self.match = match
self.joker=joker
def is_request(self, req):
return req.haslayer(DNS) and req.getlayer(DNS).qr == 0
def make_reply(self, req):
ip = req.getlayer(IP)
dns = req.getlayer(DNS)
resp = IP(dst=ip.src, src=ip.dst)/UDP(dport=ip.sport,sport=ip.dport)
rdata = self.match.get(dns.qd.qname, self.joker)
resp /= DNS(id=dns.id, qr=1, qd=dns.qd,
an=DNSRR(rrname=dns.qd.qname, ttl=10, rdata=rdata))
return resp
|