def invalid_over2k(request):
"""Sends a reply > 2048 bytes with invalid ID"""
flags = DNSFlags(request.header.flags.flags_int())
flags.set(["QR", "AA"])
question = request.questions[0]
header = DNSHeader(0x0000, flags, 1, 0, 0, 0)
return header.bytes() + question.bytes() + b"\x42" * 2048
def valid_over2k(request):
"""Sends a reply > 2048 bytes with valid header/question"""
flags = DNSFlags(request.header.flags.flags_int())
flags.set(["QR", "AA"])
question = request.questions[0]
header = DNSHeader(request.header.ID, flags, 1, 0, 0, 0)
return header.bytes() + question.bytes() + b"\x42" * 32768
def truncated_over1k(request):
"""Sends a reply > 1024 bytes (but less than 2048 bytes) with valid header/question and TC flag set"""
flags = DNSFlags(request.header.flags.flags_int())
flags.set(["QR", "AA", "TC"])
question = request.questions[0]
header = DNSHeader(request.header.ID, flags, 1, 0, 0, 0)
return header.bytes() + question.bytes() + b"\x42" * 1024
def valid_exact1k(request):
"""Sends a reply exactly 1024 bytes long with valid header/question"""
flags = DNSFlags(request.header.flags.flags_int())
flags.set(["QR", "AA"])
question = request.questions[0]
header = DNSHeader(request.header.ID, flags, 1, 0, 0, 0)
padlen = 1024 - len(header.bytes()) - len(question.bytes())
return header.bytes() + question.bytes() + b"\x42" * padlen
def payload_size(request, size):
"""Send a reply with a valid payload of specified length"""
flags = DNSFlags(request.header.flags.flags_int())
flags.set(["QR", "AA"])
question = request.questions[0]
rtype = question.qtype
if rtype == 28:
answer = dw(0xc00c) + dw(rtype) + dw(1) + dd(0) + dw(16) + b"\x42" * 16
elif rtype == 1:
answer = dw(0xc00c) + dw(rtype) + dw(1) + dd(0) + dw(4) + b"\x42" * 4
ancount = 1 + size // len(answer)
header = DNSHeader(request.header.ID, flags, 1, ancount, 0, 0)
return header.bytes() + question.bytes() + b"".join([answer[:-2] + dw(i) for i in range(ancount)])