def __init__(self, profile, header):
rule_id = header.RULE_ID
dtag = header.DTAG
w = header.W
header = Header(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=w,
fcn='',
c='1')
self.header = header
padding = ''
self.padding = padding
# if the Header does not end at an L2 Word boundary,
# append bits set to 1 as needed to reach the next L2 Word boundary.
while len(header.string + padding) % profile.L2_WORD_SIZE != 0:
padding += '1'
# append exactly one more L2 Word with bits all set to ones.
padding += '1' * profile.L2_WORD_SIZE
#must check this method
# sigfox ACK must be of downlink MTU size
while len(header.string + padding) < profile.DOWNLINK_MTU:
padding += '1'
super().__init__(profile,
rule_id,
dtag,
w,
c='1',
bitmap='',
padding=padding)
def __init__(self, profile, fragment):
self.profile = profile
self.header_length = profile.HEADER_LENGTH
self.rule_id_size = profile.RULE_ID_SIZE
self.t = profile.T
self.n = profile.N
self.m = profile.M
header = zfill(
str(bin(int.from_bytes(fragment[0], 'big')))[2:],
self.header_length)
payload = fragment[1]
rule_id = str(header[:self.rule_id_size])
dtag = str(header[self.rule_id_size:self.rule_id_size + self.t])
window = str(header[self.rule_id_size + self.t:self.rule_id_size +
self.t + self.m])
fcn = str(header[self.rule_id_size + self.t +
self.m:self.rule_id_size + self.t + self.m + self.n])
c = ""
self.header = Header(self.profile, rule_id, dtag, window, fcn, c)
self.payload = payload
def fragment(self):
payload_max_length = int(
(self.profile.MTU - self.profile.HEADER_LENGTH) / 8)
message = self.schc_packet
fragment_list = []
n = self.profile.N
m = self.profile.M
number_of_fragments = int(
ceil(float(len(message)) / payload_max_length))
print("[FRGM] Fragmenting message into " + str(number_of_fragments) +
" pieces...")
for i in range(number_of_fragments):
w = zfill(bin(int(floor((i / (2**n - 1) % (2**m)))))[2:], 2)
fcn = zfill(bin((2**n - 2) - (i % (2**n - 1)))[2:], 3)
fragment_payload = message[i * payload_max_length:(i + 1) *
payload_max_length]
if len(fragment_payload) < payload_max_length:
header = Header(self.profile,
rule_id="00",
dtag="0",
w=w,
fcn="111",
c=0)
else:
header = Header(self.profile,
rule_id="00",
dtag="0",
w=w,
fcn=fcn,
c=0)
fragment = [header.bytes, fragment_payload]
# print("[" + header.string + "]" + str(fragment_payload))
fragment_list.append(fragment)
print("[FRGM] Fragmentation complete.")
return fragment_list
def __init__(self, profile, header):
self.profile = profile
rule_id = header.RULE_ID
dtag = header.DTAG
w = header.W
fcn = "1" * profile.N
self.header = Header(profile, rule_id, dtag, w, fcn)
while len(self.header.string + self.padding) < profile.UPLINK_MTU:
self.padding += '0'
super().__init__(profile, [bitstring_to_bytes(rule_id + dtag + w + fcn), self.padding.encode()])
def __init__(self, profile, rule_id, dtag, w):
self.profile = profile
self.header = Header(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=w,
fcn="1" * profile.N,
c="")
while len(self.header.string + self.padding) < profile.MTU:
self.padding += '0'
print(self.header.string + self.padding)
def __init__(self, profile, rule_id, dtag, w):
self.profile = profile
self.header = Header(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=w,
fcn='',
c='1')
# if the Header does not end at an L2 Word boundary, append bits set to 1 as needed to reach the next L2 Word boundary.
while len(self.header.string +
self.padding) % profile.L2_WORD_SIZE != 0:
self.padding += '1'
# append exactly one more L2 Word with bits all set to ones.
self.padding += '1' * profile.L2_WORD_SIZE
def fragment(self):
payload_max_length = int(
(self.profile.MTU - self.profile.HEADER_LENGTH) / 8)
message = self.schc_packet
fragment_list = []
n = self.profile.N
m = self.profile.M
number_of_fragments = int(
ceil(float(len(message)) / payload_max_length))
if len(message) == 0:
number_of_fragments = 1 #This is used to send 0-Payload SCHC Packets
print("[FRGM] Fragmenting message into " + str(number_of_fragments) +
" pieces...")
#check if the packet size can be transmitted or not
if len(fragment_list) > (2**self.profile.M) * self.profile.WINDOW_SIZE:
print(len(fragment_list))
print((2**self.profile.M) * self.profile.WINDOW_SIZE)
print(
"The SCHC packet cannot be fragmented in 2 ** M * WINDOW_SIZE fragments or less. A Rule ID cannot be selected."
)
# What does this mean?
# Sending packet does not fit (should be tested in fragmentation)
for i in range(number_of_fragments):
w = zfill(
bin(int(floor((i / (2**n - 1) % (2**m)))))[2:], self.profile.M)
fcn = zfill(bin((2**n - 2) - (i % (2**n - 1)))[2:], self.profile.N)
fragment_payload = message[i * payload_max_length:(i + 1) *
payload_max_length]
if len(self.schc_packet) <= 300:
if len(fragment_payload) < payload_max_length or i == (
len(range(number_of_fragments)) - 1):
header = Header(self.profile,
rule_id="000",
dtag="",
w=w,
fcn="111",
c=0)
else:
header = Header(self.profile,
rule_id="000",
dtag="",
w=w,
fcn=fcn,
c=0)
else:
if len(fragment_payload) < payload_max_length or i == (
len(range(number_of_fragments)) - 1):
header = Header(self.profile,
rule_id="00100000",
dtag="",
w=w,
fcn="11111",
c=0)
else:
header = Header(self.profile,
rule_id="00100000",
dtag="",
w=w,
fcn=fcn,
c=0)
fragment = [header.bytes, fragment_payload]
# print("[" + header.string + "]" + str(fragment_payload))
fragment_list.append(fragment)
print("[FRGM] Fragmentation complete.")
return fragment_list
# direction = input("DIRECTION: ")
# mode = input("MODE: ")
# mtu = input("MTU: ")
# if protocol_name == "SIGFOX":
# protocol = Sigfox(direction, mode)
profile = Sigfox("UPLINK", "ACK ON ERROR")
MTU = profile.MTU
with open("pollito_14x14.png", "rb") as data:
f = data.read()
payload = bytearray(f)
print("The payload to be transmitted is: " + str(payload))
test_header = Header(profile, rule_id="RR", dtag="D", w="WW", fcn="000", c=0)
test_header.test()
fragmenter = Fragmenter(profile, payload)
fragment_list = fragmenter.fragment()
print("Fragments:")
for fragment in fragment_list:
print(fragment)
if Fragment(profile, fragment_list[-1]).is_all_1() is True:
print("All-1 condition satisfied")
else:
print("All-1 condition NOT satisfied")
# print("Rebuilding message...")