/usr/lib/python2.7/dist-packages/ripe/atlas/sagan/helpers/abuf.py is in python-ripe-atlas-sagan 1.1.8-1.
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 | # Copyright (c) 2015 RIPE NCC
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from __future__ import absolute_import
import base64
import codecs
import struct
def base64_encodebytes(data):
if hasattr(base64, "encodebytes"):
return base64.encodebytes(data)
return base64.encodestring(data)
class AbufParser(object):
DNS_CTYPE = "ASCII"
@classmethod
def parse(cls, buf, options=None):
"""
According to Philip, an abuf is like a TARDIS: it's bigger on the inside
"""
error = []
do_header = True
do_question = True
do_answer = True
do_authority = True
do_additional = True
do_options = True
if options and isinstance(options, dict):
if 'DO_Header' in options and not options['DO_Header']:
do_header = options['DO_Header']
if 'DO_Question' in options and not options['DO_Question']:
do_question = options['DO_Question']
if 'DO_Answer' in options and not options['DO_Answer']:
do_answer = options['DO_Answer']
if 'DO_Authority' in options and not options['DO_Authority']:
do_authority = options['DO_Authority']
if 'DO_Additional' in options and not options['DO_Additional']:
do_additional = options['DO_Additional']
if 'DO_Options' in options and not options['DO_Options']:
do_options = options['DO_Options']
dnsres = {}
offset = 0
offset, hdr = cls._parse_header(buf, offset, error)
if do_header:
dnsres['HEADER'] = hdr
for i in range(hdr['QDCOUNT']):
res = cls._do_query(buf, offset, error)
if res is None:
e = ('additional', offset, ('_do_query failed, additional record %d' % i))
error.append(e)
dnsres['ERROR'] = error
return dnsres
offset, qry = res
if do_question:
if i == 0:
dnsres['QuestionSection'] = [qry]
else:
dnsres['QuestionSection'].append(qry)
for i in range(hdr['ANCOUNT']):
res = cls._do_rr(buf, offset, error)
if res is None:
e = ('additional', offset, ('_do_rr failed, additional record %d' % i))
error.append(e)
dnsres['ERROR'] = error
return dnsres
offset, rr = res
if do_answer:
if i == 0:
dnsres['AnswerSection'] = [rr]
else:
dnsres['AnswerSection'].append(rr)
for i in range(hdr['NSCOUNT']):
res = cls._do_rr(buf, offset, error)
if res is None:
e = ('additional', offset, ('_do_rr failed, additional record %d' % i))
error.append(e)
dnsres['ERROR'] = error
return dnsres
offset, rr = res
if do_authority:
if i == 0:
dnsres['AuthoritySection'] = [rr]
else:
dnsres['AuthoritySection'].append(rr)
for i in range(hdr['ARCOUNT']):
res = cls._do_rr(buf, offset, error)
if res is None:
e = ('additional', offset, ('_do_rr failed, additional record %d' % i))
error.append(e)
dnsres['ERROR'] = error
return dnsres
offset, rr = res
if do_options:
if "EDNS0" in rr:
dnsres['EDNS0'] = rr['EDNS0']
continue
if do_additional:
if 'AdditionalSection' in dnsres:
dnsres['AdditionalSection'].append(rr)
else:
dnsres['AdditionalSection'] = [rr]
if offset < len(buf):
e = ('end', offset, 'trailing garbage, buf size = %d' % len(buf))
error.append(e)
#result['decodedabufs_with_ERROR'] += 1
dnsres['ERROR'] = error
return dnsres
@staticmethod
def _opcode_to_text(opcode):
return { 0: 'QUERY', 1: 'IQUERY', 2: 'STATUS',
4: 'NOTIFY', 5: 'UPDATE'}.get(opcode, opcode)
@staticmethod
def _class_to_text(rdataclass):
return {0: 'RESERVED0', 1: 'IN', 3: 'CH', 4: 'HS',
254: 'NONE', 255: 'ANY'}.get(rdataclass, rdataclass)
@staticmethod
def _rcode_to_text(rcode):
return {0: 'NOERROR', 1: 'FORMERR', 2: 'SERVFAIL', 3: 'NXDOMAIN',
4: 'NOTIMP', 5: 'REFUSED', 6: 'YXDOMAIN', 7: 'YXRRSET',
8: 'NXRRSET', 9: 'NOTAUTH', 10: 'NOTZONE',
16: 'BADVERS'}.get(rcode, rcode)
@staticmethod
def _type_to_text(rdatatype):
return {0: 'NONE', 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', 19: 'X25',
20: 'ISDN', 21: 'RT', 22: 'NSAP', 23: 'NSAP_PTR', 24: 'SIG', 25: 'KEY',
26: 'PX', 27: 'GPOS', 28: 'AAAA', 29: 'LOC', 30: 'NXT', 33: 'SRV',
35: 'NAPTR', 36: 'KX', 37: 'CERT', 38: 'A6', 39: 'DNAME', 41: 'OPT',
42: 'APL', 43: 'DS', 44: 'SSHFP', 45: 'IPSECKEY', 46: 'RRSIG', 47: 'NSEC',
48: 'DNSKEY', 49: 'DHCID', 50: 'NSEC3', 51: 'NSEC3PARAM', 52: 'TLSA',
55: 'HIP', 99: 'SPF', 103: 'UNSPEC', 249: 'TKEY', 250: 'TSIG', 251: 'IXFR',
252: 'AXFR', 253: 'MAILB', 254: 'MAILA', 255: 'ANY', 32768: 'TA',
32769: 'DLV'}.get(rdatatype, rdatatype)
@classmethod
def _bytes_as_hex_str(cls, b):
b_as_hex = codecs.getencoder('hex_codec')(b)[0]
b_as_hex_str = b_as_hex.decode(cls.DNS_CTYPE)
return b_as_hex_str
@classmethod
def _types_bitmap(cls, data, error):
bits = []
o = 0
while o < len(data):
fmt = "!BB"
fmtsz = struct.calcsize(fmt)
dat = data[o:o+fmtsz]
if len(dat) != fmtsz:
e = ("_types_bitmap", o, 'offset out of range: data size = %d' % len(data))
error.append(e)
return None
block, bytes = struct.unpack(fmt, dat)
o += fmtsz
for i in range(bytes):
b = struct.unpack("!B", data[o+i:o+i+1])[0]
for j in range(8):
if b & (1 << (7-j)):
bits.append((block*32+i)*8+j)
o += bytes
return bits
@classmethod
def _parse_header(cls, buf, offset, error):
fmt = "!HHHHHH"
reqlen = struct.calcsize(fmt)
strng = buf[offset:offset + reqlen]
if len(strng) != reqlen:
e = ("_parse_header", offset, 'offset out of range: buf size = %d' % len(buf))
error.append(e)
return None
res = struct.unpack(fmt, strng)
hdr = {
"ID": res[0]
}
qr = 0x8000
opcode_mask = 0x7800
opcode_shift = 11
aa = 0x0400
tc = 0x0200
rd = 0x0100
ra = 0x0080
z_mask = 0x0040
z_shift = 6
ad = 0x0020
cd = 0x0010
rcode_mask = 0x000F
rcode_shift = 0
hdr['QR'] = bool(res[1] & qr)
hdr['OpCode'] = cls._opcode_to_text((res[1] & opcode_mask) >> opcode_shift)
hdr['AA'] = bool(res[1] & aa)
hdr['TC'] = bool(res[1] & tc)
hdr['RD'] = bool(res[1] & rd)
hdr['RA'] = bool(res[1] & ra)
hdr['Z'] = (res[1] & z_mask) >> z_shift
hdr['AD'] = bool(res[1] & ad)
hdr['CD'] = bool(res[1] & cd)
hdr['ReturnCode'] = cls._rcode_to_text((res[1] & rcode_mask) >> rcode_shift)
hdr['QDCOUNT'] = res[2]
hdr['ANCOUNT'] = res[3]
hdr['NSCOUNT'] = res[4]
hdr['ARCOUNT'] = res[5]
return offset + reqlen, hdr
@classmethod
def _do_query(cls, buf, offset, error):
qry = {}
res = cls._do_name(buf, offset, 0, error)
if res is None:
e = ("_do_query", offset, "_do_name failed")
error.append(e)
return None
offset, name = res
qry['Qname'] = name
fmt = "!HH"
reqlen = struct.calcsize(fmt)
strng = buf[offset:offset + reqlen]
if len(strng) != reqlen:
e = ("_do_query", offset, 'offset out of range: buf size = %d' % len(buf))
error.append(e)
return None
res = struct.unpack(fmt, strng)
qry['Qtype'] = cls._type_to_text(res[0])
qry['Qclass'] = cls._class_to_text(res[1])
return offset + reqlen, qry
@classmethod
def _clean_up_string(cls, strng):
result = ''
strng = bytearray(strng)
for o in strng:
if o < ord(' ') or o > ord('~'):
result += ("\\%03d" % o)
elif o == ord('"') or o == ord('\\'):
result += "\\" + chr(o)
else:
result += chr(o)
return result
@classmethod
def _do_rr(cls, buf, offset, error):
edns0_opt_nsid = 3 # this is also hardcoded in dns.edns.py
rr = {}
res = cls._do_name(buf, offset, 0, error)
if res is None:
e = ("_do_rr", offset, "_do_name failed")
error.append(e)
return None
offset, name = res
rr['Name'] = name
fmt = "!HHIH"
reqlen = struct.calcsize(fmt)
dat = buf[offset:offset + reqlen]
if len(dat) != reqlen:
e = ("_do_rr", offset, 'offset out of range: buf size = %d' % len(buf))
error.append(e)
return None
res = struct.unpack(fmt, dat)
rr['Type'] = cls._type_to_text(res[0])
rr['Class'] = cls._class_to_text(res[1])
rr['TTL'] = res[2]
rr['RDlength'] = res[3]
offset += reqlen
rdata = buf[offset:offset + rr['RDlength']]
rdata_offset = offset
offset = offset + rr['RDlength']
if rr['Type'] == 'OPT': # this is per cls._type_to_text function
edns0 = {
'UDPsize': res[1],
'ExtendedReturnCode': res[2] >> 24,
'Version': (res[2] & 0x00ff0000) >> 16,
'Z': (res[2] & 0x007fff),
'Type': 'OPT',
'Option': [],
'Name': name,
}
if res[2] & 0x8000:
edns0['DO']= True
o = 0
while o < len(rdata):
fmt = "!HH"
reqlen = struct.calcsize(fmt)
dat = rdata[o:o + reqlen]
if len(dat) != reqlen:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
res = struct.unpack(fmt, dat)
opt = {
'OptionCode': res[0],
'OptionLength': res[1],
}
o += reqlen
if opt['OptionCode'] == edns0_opt_nsid:
opt['OptionName'] = 'NSID'
nsid = rdata[o:o + opt['OptionLength']]
nsid_as_str = nsid.decode(cls.DNS_CTYPE)
opt[opt['OptionName']] = nsid_as_str
o = o + opt['OptionLength']
edns0['Option'].append(opt)
del rr['Class']
del rr['RDlength']
del rr['TTL']
del rr['Name']
del rr['Type']
rr['EDNS0'] = edns0
return offset, rr
if rr['Class'] == "IN":
# this is per cls._type_to_text function
if rr['Type'] == 'A':
fmt = "!BBBB"
reqlen = struct.calcsize(fmt)
if reqlen > len(rdata):
e = ("_do_rr", rdata_offset, 'rdata too small: size = %d' % len(rdata))
error.append(e)
return None
rr['Address'] = '.'.join(str(byte) for byte in struct.unpack(fmt, rdata))
elif rr['Type'] == 'AAAA':
fmt = "!HHHHHHHH"
reqlen = struct.calcsize(fmt)
if reqlen > len(rdata):
e = ("_do_rr", rdata_offset, 'rdata too small: size = %d' % len(rdata))
error.append(e)
return None
addr = ':'.join(("%x" % quad) for quad in struct.unpack(fmt, rdata))
rr['Address'] = addr
elif rr['Type'] == 'CNAME':
doffset, name = cls._do_name(buf, rdata_offset, 0, error)
rr['Target'] = name
elif rr['Type'] == 'DNSKEY':
fmt = '!HBB'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['Flags'], rr['Protocol'], rr['Algorithm'] =\
struct.unpack(fmt, dat)
key = rdata[struct.calcsize(fmt):]
key_as_base64 = base64_encodebytes(key)
key_as_base64_str = key_as_base64.decode(cls.DNS_CTYPE)
rr['Key'] = ''.join(key_as_base64_str.split())
elif rr['Type'] == 'DS':
fmt = '!HBB'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['Tag'], rr['Algorithm'], rr['DigestType'] = \
struct.unpack(fmt, dat)
key = rdata[struct.calcsize(fmt):]
rr['DelegationKey'] = cls._bytes_as_hex_str(key)
elif rr['Type'] == 'HINFO':
fmt = "!B"
fmtsz = struct.calcsize(fmt)
o = 0
for tag in ('Cpu', 'Os'):
dat = rdata[o:o+fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset,
'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
o += fmtsz
slen = struct.unpack(fmt, dat)[0]
strng = rdata[o:o+slen]
if len(strng) < slen:
e = ("_do_rr", rdata_offset,
'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr[tag] = cls._clean_up_string(strng)
o += slen
elif rr['Type'] == 'MX':
fmt = '!H'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['Preference'] = struct.unpack(fmt, dat)[0]
rr_offset, rr['MailExchanger'] = cls._do_name(buf, rdata_offset + fmtsz, 0, error)
elif rr['Type'] == 'NS':
doffset, name = cls._do_name(buf, rdata_offset, 0, error)
rr['Target'] = name
elif rr['Type'] == 'NSEC':
doffset, name = cls._do_name(buf, rdata_offset, 0, error)
rr['NextDomainName'] = name
o = doffset-rdata_offset
bits = cls._types_bitmap(rdata[o:rr['RDlength']], error)
if bits is None:
e = ("_do_rr", 'failed to parse types bitmap')
error.append(e)
return None
rr['Types'] = bits
elif rr['Type'] == 'NSEC3':
fmt = '!BBHB'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['HashAlg'], rr['Flags'], rr['Iterations'], SaltLength = struct.unpack(fmt, dat)
o = fmtsz
salt = rdata[o:o+SaltLength]
rr['Salt']= cls._bytes_as_hex_str(salt)
o += SaltLength
fmt = '!B'
fmtsz = struct.calcsize(fmt)
dat = rdata[o:o+fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
HashLength = struct.unpack(fmt, dat)[0]
o += fmtsz
hash = rdata[o:o+HashLength]
b32str = base64.b32encode(hash)
while b32str[-1] == '=':
b32str = b32str[:-1]
# Note that we need extended hexadecimal instead of actual base32
# Just remap the input
hexmap = {
'A': '0', 'B': '1', 'C': '2', 'D': '3',
'E': '4', 'F': '5', 'G': '6', 'H': '7',
'I': '8', 'J': '9', 'K': 'a', 'L': 'b',
'M': 'c', 'N': 'd', 'O': 'e', 'P': 'f',
'Q': 'g', 'R': 'h', 'S': 'i', 'T': 'j',
'U': 'k', 'V': 'l', 'W': 'm', 'X': 'n',
'Y': 'o', 'Z': 'p', '2': 'q', '3': 'r',
'4': 's', '5': 't', '6': 'u', '7': 'v'
}
b32str = ''.join([hexmap[l] for l in b32str.decode(cls.DNS_CTYPE) ])
rr['Hash'] = b32str
o += HashLength
bits = cls._types_bitmap(rdata[o:rr['RDlength']], error)
if bits is None:
e = ("_do_rr", 'failed to parse types bitmap')
error.append(e)
return None
rr['Types'] = bits
elif rr['Type'] == 'NSEC3PARAM':
fmt = '!BBHB'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['Algorithm'], rr['Flags'], rr['Iterations'], SaltLength = struct.unpack(fmt, dat)
o = fmtsz
salt = rdata[o:o+SaltLength]
rr['Salt'] = cls._bytes_as_hex_str(salt)
o += SaltLength
elif rr['Type'] == 'PTR':
doffset, name = cls._do_name(buf, rdata_offset, 0, error)
rr['Target'] = name
elif rr['Type'] == 'RRSIG':
# https://tools.ietf.org/html/rfc4034#section-3.1
""" The RDATA for an RRSIG RR consists of a 2 octet Type
Covered field, a 1 octet Algorithm field, a 1 octet Labels
field, a 4 octet Original TTL field, a 4 octet Signature
Expiration field, a 4 octet Signature Inception field, a 2
octet Key tag, the Signer's Name field, and the Signature
field. """
fmt = "!HBBIIIH"
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['TypeCovered'], rr['Algorithm'], rr['Labels'], rr['OriginalTTL'], rr['SignatureExpiration'], rr['SignatureInception'], rr['KeyTag'] = struct.unpack(fmt, dat)
rr['TypeCovered'] = cls._type_to_text( rr['TypeCovered'] )
res = cls._do_name(rdata, fmtsz, 0, error)
if res is None:
e = ("_do_rr", offset, "_do_name failed")
error.append(e)
return None
signature_offset, rr['SignerName'] = res
sig = rdata[signature_offset:]
#sig_as_base64 = base64.encodebytes(sig)
sig_as_base64 = base64_encodebytes(sig)
sig_as_base64_str = sig_as_base64.decode(cls.DNS_CTYPE)
rr['Signature'] = ''.join(sig_as_base64_str.split())
elif rr['Type'] == 'SOA':
offset_name = cls._do_name(buf, rdata_offset, 0, error)
if offset_name is None:
e = ("do_rr", rdata_offset, '_do_name failed')
error.append(e)
return None
rr_offset, rr['MasterServerName'] = offset_name
offset_name = cls._do_name(buf, rr_offset, 0, error)
if offset_name is None:
e = ("do_rr", rr_offset, '_do_name failed')
error.append(e)
return None
rr_offset, rr['MaintainerName'] = offset_name
fmt = '!IIIII'
fmtsz = struct.calcsize(fmt)
dat = buf[rr_offset:rr_offset + fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rr_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['Serial'], rr['Refresh'], rr['Retry'], rr['Expire'], rr['NegativeTtl'] = struct.unpack(fmt, dat)
elif rr['Type'] == 'SRV':
fmt = '!HHH'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
(rr['Priority'], rr['Weight'], rr['Port']) = struct.unpack(fmt, dat)
rr_offset, rr['Target'] = cls._do_name(buf, rdata_offset+fmtsz, 0, error)
elif rr['Type'] == 'SSHFP':
fmt = '!BB'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
(rr['Algorithm'], rr['DigestType']) = struct.unpack(fmt, dat)
rr['Fingerprint'] = cls._bytes_as_hex_str(rdata[fmtsz:])
elif rr['Type'] == 'TLSA':
fmt = '!BBB'
fmtsz = struct.calcsize(fmt)
dat = rdata[:fmtsz]
if len(dat) != fmtsz:
e = ("_do_rr", rdata_offset, 'offset out of range: rdata size = %d' % len(rdata))
error.append(e)
return None
rr['CertUsage'], rr['Selector'], rr['MatchingType']= \
struct.unpack(fmt, dat)
rr['CertAssData'] = cls._bytes_as_hex_str(rdata[fmtsz:])
if rr['Type'] == 'TXT':
if rr['Class'] == "IN" or rr['Class'] == "CH":
fmt = "!B"
reqlen = struct.calcsize(fmt)
o = 0
rr['Data'] = []
while o < len(rdata):
strng = rdata[o:o+reqlen]
if len(strng) != reqlen:
e = ("_do_rr", rdata_offset,
'offset out of range: rdata size = %d' %
len(rdata))
error.append(e)
return None
res = struct.unpack(fmt, strng)
llen = res[0]
o += reqlen
strng = rdata[o:o+llen]
if len(strng) < llen:
e = ("_do_rr", rdata_offset,
'offset out of range: rdata size = %d' %
len(rdata))
error.append(e)
return None
strng = cls._clean_up_string(strng)
rr['Data'].append(strng)
o += llen
if isinstance(rr["Class"], int) or isinstance(rr["Type"], int):
# Unknown class or type. Just add a RDATA field with hex data
rr['Rdata'] = cls._bytes_as_hex_str(rdata)
return offset, rr
@classmethod
def _do_name(cls, buf, offset, recurs, error):
if recurs >= 256:
e = ("_do_name", offset, 'too much recursion')
error.append(e)
return None
name = ''
while True:
fmt = "!B"
reqlen = struct.calcsize(fmt)
strng = buf[offset:offset + reqlen]
if len(strng) != reqlen:
e = ("_do_name", offset, 'offset out of range: buf size = %d' % len(buf))
error.append(e)
return None
res = struct.unpack(fmt, strng)
llen = res[0]
if llen <= 63:
# Label
offset += 1
label = buf[offset:offset + llen]
offset = offset + llen
label_as_str = cls._clean_up_string(label)
if name == '' or label_as_str != '':
name = name + label_as_str + '.'
if llen == 0:
break
elif llen >= 0xC0:
fmt = "!H"
reqlen = struct.calcsize(fmt)
strng = buf[offset:offset + reqlen]
if len(strng) != reqlen:
e = ("_do_name", offset, 'offset out of range: buf size = %d' % len(buf))
error.append(e)
return None
res = struct.unpack(fmt, strng)
poffset = res[0] & ~0xC000
n = cls._do_name(buf, poffset, recurs+1, error)
if n is None:
e = ("_do_name", poffset,
'bad offset %d at offset %d' % (poffset, offset))
error.append(e)
return None
poffset, pname = n
offset += reqlen
name = name + pname
break
else:
e = ("_do_name", offset, 'bad len 0x%x' % llen)
error.append(e)
return None
return offset, name
__all__ = (
"DnsResult",
)
|