def hello_get(request):
"""HTTP Cloud Function.
Args:
request (flask.Request): The request object.
<http://flask.pocoo.org/docs/1.0/api/#flask.Request>
Returns:
The response text, or any set of values that can be turned into a
Response object using `make_response`
<http://flask.pocoo.org/docs/1.0/api/#flask.Flask.make_response>.
"""
# Wait for an HTTP POST request.
if request.method == 'POST':
# Get request JSON.
print("POST RECEIVED")
request_dict = request.get_json()
print('Received Sigfox message: {}'.format(request_dict))
# Get data and Sigfox Sequence Number.
fragment = request_dict["data"]
sigfox_sequence_number = request_dict["seqNumber"]
# Initialize Cloud Storage variables.
BUCKET_NAME = config.BUCKET_NAME
# Parse fragment into "fragment = [header, payload]
header_first_hex = fragment[0]
if header_first_hex == '0' or header_first_hex == '1':
header = bytes.fromhex(fragment[:2])
payload = bytearray.fromhex(fragment[2:])
header_bytes = 1
elif header_first_hex == 'f' or header_first_hex == '2':
header = bytearray.fromhex(fragment[:4])
payload = bytearray.fromhex(fragment[4:])
header_bytes = 2
else:
print("Wrong header in fragment")
return 'wrong header', 204
if bytearray.fromhex(fragment[2:]).decode() == "CLEAN":
try:
_ = requests.post(url=config.CLEAN_URL,
json={
"header_bytes": header_bytes,
"not_delete_dl_losses": "True"
},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
return '', 204
elif bytearray.fromhex(fragment[2:]).decode() == "CLEAN_ALL":
try:
_ = requests.post(url=config.CLEAN_URL,
json={
"header_bytes": header_bytes,
"not_delete_dl_losses": "False"
},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
return '', 204
data = [header, payload]
# Initialize SCHC variables.
profile = Sigfox("UPLINK", "ACK ON ERROR", header_bytes)
buffer_size = profile.UPLINK_MTU
n = profile.N
m = profile.M
# If fragment size is greater than buffer size, ignore it and end function.
if len(fragment
) / 2 * 8 > buffer_size: # Fragment is hex, 1 hex = 1/2 byte
return json.dumps(
{"message":
"Fragment size is greater than buffer size D:"}), 200
# If the folder named "all windows" does not exist, create it along with all subdirectories.
if not exists_blob("all_windows/"):
print("INITIALIZING... (be patient)")
create_folder("all_windows/")
# For each window in the SCHC Profile, create its blob.
for i in range(2**m):
create_folder("all_windows/window_%d/" % i)
# For each fragment in the SCHC Profile, create its blob.
for j in range(2**n - 1):
upload_blob(
"", "all_windows/window_%d/fragment_%d_%d" % (i, i, j))
# Create the blob for each bitmap.
if not exists_blob(
"all_windows/window_%d/bitmap_%d" %
(i, i) or size_blob("all_windows/window_%d/bitmap_%d" %
(i, i)) == 0):
bitmap = ""
for b in range(profile.BITMAP_SIZE):
bitmap += "0"
upload_blob(bitmap,
"all_windows/window_%d/bitmap_%d" % (i, i))
print("BLOBs created")
# Find current experiment number
current_experiment = 0
for blob in blob_list():
if blob.startswith("DL_LOSSES_"):
current_experiment += 1
print(f"This is the {current_experiment}th experiment.")
# Initialize empty window
window = []
for i in range(2**n - 1):
window.append([b"", b""])
# Compute the fragment compressed number (FCN) from the Profile
fcn_dict = {}
for j in range(2**n - 1):
fcn_dict[zfill(bin((2**n - 2) - (j % (2**n - 1)))[2:], n)] = j
# Convert to a Fragment class for easier manipulation.
fragment_message = Fragment(profile, data)
if 'enable_losses' in request_dict and not (
fragment_message.is_all_0() or fragment_message.is_all_1()):
if request_dict['enable_losses']:
loss_rate = request_dict["loss_rate"]
# loss_rate = 10
coin = random.random()
print(f'loss rate: {loss_rate}, random toss:{coin * 100}')
if coin * 100 < loss_rate:
print("[LOSS] The fragment was lost.")
if fragment_message.is_all_1():
last_sequence_number = read_blob("SSN")
print("SSN is {} and last SSN is {}".format(
sigfox_sequence_number, last_sequence_number))
if int(sigfox_sequence_number) - int(
last_sequence_number) == 1:
# We do that to save the last SSN value for future use (when the next All-1 Arrives)
# In a Real Loss Scenario we will not know the SSN...
upload_blob(sigfox_sequence_number, "SSN")
return 'fragment lost', 204
# Get current window for this fragment.
current_window = int(fragment_message.HEADER.W, 2)
# Get the current bitmap.
bitmap = read_blob("all_windows/window_%d/bitmap_%d" %
(current_window, current_window))
if fragment_message.is_sender_abort():
print("Sender-Abort received")
return 'Sender-Abort received', 204
# Try getting the fragment number from the FCN dictionary.
try:
fragment_number = fcn_dict[fragment_message.HEADER.FCN]
upload_blob(fragment_number, "fragment_number")
time_received = int(request_dict["time"])
if exists_blob("timestamp"):
# Check time validation.
last_time_received = int(read_blob("timestamp"))
# If this is not the very first fragment and the inactivity timer has been reached, ignore the message.
if str(fragment_number) != "0" and str(
current_window
) != "0" and time_received - last_time_received > profile.INACTIVITY_TIMER_VALUE:
print("[RECV] Inactivity timer reached. Ending session.")
receiver_abort = ReceiverAbort(profile,
fragment_message.HEADER)
print("Sending Receiver Abort")
response_json = send_ack(request_dict, receiver_abort)
print(f"Response content -> {response_json}")
return response_json, 200
# Upload current timestamp.
upload_blob(time_received, "timestamp")
# Print some data for the user.
print("[RECV] This corresponds to the " + str(fragment_number) +
"th fragment of the " + str(current_window) + "th window.")
print("[RECV] Sigfox sequence number: " +
str(sigfox_sequence_number))
# Controlled Errors check
# losses_mask = read_blob(BUCKET_NAME, "all_windows/window_%d/losses_mask_%d" % (current_window, current_window))
# if (losses_mask[fragment_number]) != '0':
# losses_mask = replace_bit(losses_mask, fragment_number, str(int(losses_mask[fragment_number])-1))
# upload_blob(BUCKET_NAME, losses_mask, "all_windows/window_%d/losses_mask_%d" % (current_window, current_window))
# print("[LOSS] The fragment was lost.")
# return 'fragment lost', 204
# Update bitmap and upload it.
bitmap = replace_bit(bitmap, fragment_number, '1')
upload_blob(
bitmap, "all_windows/window_%d/bitmap_%d" %
(current_window, current_window))
# Upload the fragment data.
upload_blob(
data[0].decode("ISO-8859-1") + data[1].decode("utf-8"),
"all_windows/window_%d/fragment_%d_%d" %
(current_window, current_window, fragment_number))
# If the FCN could not been found, it almost certainly is the final fragment.
except KeyError:
print("[RECV] This seems to be the final fragment.")
# Upload current timestamp.
time_received = int(request_dict["time"])
upload_blob(time_received, "timestamp")
print("is All-1:{}, is All-0:{}".format(
fragment_message.is_all_1(), fragment_message.is_all_0()))
# print("RULE_ID: {}, W:{}, FCN:{}".format(fragment.header.RULE_ID, fragment.header.W, fragment.header.FCN))
# Update bitmap and upload it.
bitmap = replace_bit(bitmap, len(bitmap) - 1, '1')
upload_blob(
bitmap, "all_windows/window_%d/bitmap_%d" %
(current_window, current_window))
# Get some SCHC values from the fragment.
rule_id = fragment_message.HEADER.RULE_ID
dtag = fragment_message.HEADER.DTAG
w = fragment_message.HEADER.W
# Get last and current Sigfox sequence number (SSN)
last_sequence_number = 0
if exists_blob("SSN"):
last_sequence_number = read_blob("SSN")
upload_blob(sigfox_sequence_number, "SSN")
# If the fragment is at the end of a window (ALL-0 or ALL-1)
if fragment_message.is_all_0() or fragment_message.is_all_1():
# Prepare the ACK bitmap. Find the first bitmap with a 0 in it.
for i in range(current_window + 1):
bitmap_ack = read_blob("all_windows/window_%d/bitmap_%d" %
(i, i))
print(bitmap_ack)
window_ack = i
if '0' in bitmap_ack:
break
# If the ACK bitmap has a 0 at the end of a non-final window, a fragment has been lost.
if fragment_message.is_all_0() and '0' in bitmap_ack:
if 'enable_dl_losses' in request_dict:
if request_dict['enable_dl_losses'] == "True":
loss_rate = request_dict["loss_rate"]
coin = random.random()
print('loss rate: {}, random toss:{}'.format(
loss_rate, coin * 100))
if coin * 100 < loss_rate:
print("[LOSS-ALL0] The Downlink NACK was lost.")
upload_blob(
read_blob(f"DL_LOSSES_{current_experiment}") +
"\n Lost DL message in window {}".format(
current_window),
f"DL_LOSSES_{current_experiment}")
return 'Downlink lost', 204
print("[ALL0] Sending ACK for lost fragments...")
print("bitmap with errors -> {}".format(bitmap_ack))
# Create an ACK message and send it.
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
print("Response content -> {}".format(response_json))
return response_json, 200
# If the ACK bitmap is complete and the fragment is an ALL-0, don't send an ACK
if fragment_message.is_all_0() and bitmap[0] == '1' and all(
bitmap):
print("[ALL0] All Fragments of current window received")
print("[ALL0] No need to send an ACK")
# print("[ALLX] Sending ACK after window...")
# Create an ACK message and send it.
# ack = ACK(profile_downlink, rule_id, dtag, w, bitmap, '0')
# response_json = send_ack(request_dict, ack)
# print("200, Response content -> {}".format(response_json))
# Response to continue, no ACK is sent Back.
return '', 204
# return response_json, 200
# If the fragment is an ALL-1
if fragment_message.is_all_1():
# response = {request_dict['device']: {'downlinkData': '080fffffffffffff'}}
# print("response -> {}".format(json.dumps(response)))
# return json.dumps(response), 200
# The bitmap in the last window follows the following regular expression: "1*0*1*"
# Since the ALL-1, if received, changes the least significant bit of the bitmap.
# For a "complete" bitmap in the last window, there shouldn't be non-consecutive zeroes:
# 1110001 is a valid bitmap, 1101001 is not.
pattern2 = re.compile("0*1")
if pattern2.fullmatch(bitmap_ack):
if 'enable_dl_losses' in request_dict:
if request_dict['enable_dl_losses'] == "True":
loss_rate = request_dict["loss_rate"]
coin = random.random()
print('loss rate: {}, random toss:{}'.format(
loss_rate, coin * 100))
if coin * 100 < loss_rate:
print("[LOSS-ALL1] The Downlink ACK was lost.")
upload_blob(
read_blob(
f"DL_LOSSES_{current_experiment}") +
"\n Lost DL message in window {}".format(
current_window),
f"DL_LOSSES_{current_experiment}")
return 'Downlink lost', 204
print("SSN is {} and last SSN is {}".format(
sigfox_sequence_number, last_sequence_number))
# Downlink Controlled Errors
dl_errors = int(read_blob("dl_errors"))
if dl_errors == 0:
last_index = 0
upload_blob(
data[0].decode("ISO-8859-1") +
data[1].decode("utf-8"),
"all_windows/window_%d/fragment_%d_%d" %
(current_window, current_window, last_index))
print(
"Info for reassemble: last_index:{}, current_window:{}"
.format(last_index, current_window))
try:
print('Activating reassembly process...')
_ = requests.post(url=config.REASSEMBLE_URL,
json={
"last_index": last_index,
"current_window":
current_window,
"header_bytes": header_bytes
},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
# Send last ACK to end communication.
print("[ALL1] Reassembled: Sending last ACK")
bitmap = ''
for k in range(profile.BITMAP_SIZE):
bitmap += '0'
last_ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='1',
bitmap=bitmap)
response_json = send_ack(request_dict, last_ack)
# return response_json, 200
# response_json = send_ack(request_dict, last_ack)
print("200, Response content -> {}".format(
response_json))
return response_json, 200
else:
dl_errors -= 1
upload_blob(dl_errors, "dl_errors")
print(
"[DL-ERROR] We simulate a downlink error. We don't send an ACK"
)
return '', 204
pattern = re.compile("1*0*1")
# If the bitmap matches the regex, check if the last two received fragments are consecutive.
if pattern.fullmatch(bitmap_ack):
print("SSN is {} and last SSN is {}".format(
sigfox_sequence_number, last_sequence_number))
# If the last two received fragments are consecutive, accept the ALL-1 and start reassembling
if 'enable_dl_losses' in request_dict:
if request_dict['enable_dl_losses'] == "True":
loss_rate = request_dict["loss_rate"]
coin = random.random()
print('loss rate: {}, random toss:{}'.format(
loss_rate, coin * 100))
if coin * 100 < loss_rate:
print("[LOSS-ALL1] The Downlink ACK was lost.")
upload_blob(
read_blob(
f"DL_LOSSES_{current_experiment}") +
"\n Lost DL message in window {}".format(
current_window),
f"DL_LOSSES_{current_experiment}")
return 'Downlink lost', 204
if int(sigfox_sequence_number) - int(
last_sequence_number) == 1:
# Downlink Controlled Errors
dl_errors = int(read_blob("dl_errors"))
if dl_errors == 0:
last_index = int(read_blob("fragment_number")) + 1
upload_blob(
data[0].decode("ISO-8859-1") +
data[1].decode("utf-8"),
"all_windows/window_%d/fragment_%d_%d" %
(current_window, current_window, last_index))
print(
"Info for reassemble: last_index:{}, current_window:{}"
.format(last_index, current_window))
try:
print('Activating reassembly process...')
_ = requests.post(url=config.REASSEMBLE_URL,
json={
"last_index": last_index,
"current_window":
current_window,
"header_bytes":
header_bytes
},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
# Send last ACK to end communication.
print("[ALL1] Reassembled: Sending last ACK")
bitmap = ''
for k in range(profile.BITMAP_SIZE):
bitmap += '0'
last_ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='1',
bitmap=bitmap)
response_json = send_ack(request_dict, last_ack)
# return response_json, 200
# response_json = send_ack(request_dict, last_ack)
print("200, Response content -> {}".format(
response_json))
return response_json, 200
else:
dl_errors -= 1
upload_blob(dl_errors, "dl_errors")
print(
"[DL-ERROR] We simulate a downlink error. We don't send an ACK"
)
return '', 204
else:
# Send NACK at the end of the window.
if 'enable_dl_losses' in request_dict:
if request_dict['enable_dl_losses'] == "True":
loss_rate = request_dict["loss_rate"]
coin = random.random()
print('loss rate: {}, random toss:{}'.format(
loss_rate, coin * 100))
if coin * 100 < loss_rate:
print(
"[LOSS-ALL1] The Downlink NACK was lost."
)
upload_blob(
read_blob(
f"DL_LOSSES_{current_experiment}")
+ "\n Lost DL message in window {}".
format(current_window),
f"DL_LOSSES_{current_experiment}")
return 'Downlink lost', 204
print(
"[ALLX] Sending NACK for lost fragments because of SSN..."
)
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
return response_json, 200
# If they are not, there is a gap between two fragments: a fragment has been lost.
# The same happens if the bitmap doesn't match the regex.
else:
# Send NACK at the end of the window.
if 'enable_dl_losses' in request_dict:
if request_dict['enable_dl_losses'] == "True":
loss_rate = request_dict["loss_rate"]
coin = random.random()
print('loss rate: {}, random toss:{}'.format(
loss_rate, coin * 100))
if coin * 100 < loss_rate:
print(
"[LOSS-ALL1] The Downlink NACK was lost.")
upload_blob(
read_blob(
f"DL_LOSSES_{current_experiment}") +
"\n Lost DL message in window {}".format(
current_window),
f"DL_LOSSES_{current_experiment}")
return 'Downlink lost', 204
print("[ALLX] Sending NACK for lost fragments...")
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
return response_json, 200
return '', 204
else:
print(
'Invalid HTTP Method to invoke Cloud Function. Only POST supported'
)
return abort(405)
# current_fragment['data'] = data
if verbose:
print("--------------------------")
print(str(i) + "th fragment:")
print("RuleID:{}, DTAG:{}, WINDOW:{}, FCN:{}".format(fragment.header.RULE_ID,fragment.header.DTAG,fragment.header.W,fragment.header.FCN))
print("SCHC Fragment: {}".format(data))
print("SCHC Fragment Payload: {}".format(fragment_list[i][1]))
current_size += len(fragment_list[i][1])
if (total_size!= 0): percent = round(float(current_size) / float(total_size) * 100, 2)
wait_receive = False
# Send the data.
# If a fragment is an All-0 or an All-1:
if fragment.is_all_0() or fragment.is_all_1():
#clearing ack variable
ack = None
print('Preparing for sending All-0 or All-1')
try:
ack = send_sigfox(the_socket, fragment, data, profile_uplink.RETRANSMISSION_TIMER_VALUE, profile_uplink, True, profile_downlink.MTU)
except SCHCReceiverAbortReceived:
print('SCHC Receiver Abort Message Received')
break
else:
send_sigfox(the_socket, fragment, data, profile_uplink.RETRANSMISSION_TIMER_VALUE, False)
# print("current_fragment:{}".format(current_fragment))
# fragments_info_array.append(current_fragment)
# the_socket.sendto(data, address)
pycom.rgbled(0x7f7f00) # yellow
the_socket.settimeout(profile_uplink.INACTIVITY_TIMER_VALUE)
# Receive fragment
try:
print(bitmap)
fragment, address = the_socket.recvfrom(buffer_size)
# A fragment has the format "fragment = [header, payload]".
data = [bytes([fragment[0]]), bytearray(fragment[1:])]
# Convert to a Fragment class for easier manipulation.
fragment_message = Fragment(profile_uplink, data)
# This avoids All-0 and All-1 fragments being lost for testing purposes.
# TODO: What happens when All-0 or All-1 get lost?
if not fragment_message.is_all_0() and not fragment_message.is_all_1():
# Lose packet with certain probability and go to the start of the loop.
coin = random.random()
if coin * 100 < loss_rate:
print("[LOSS] The packet was lost.")
continue
# Try finding the fragment number from the FCN of the fragment.
try:
fragment_number = fcn_dict[fragment_message.header.FCN]
current_window = int(fragment_message.header.W, 2)
print("[RECV] This corresponds to the " + str(fragment_number) +
"th fragment of the " + str(current_window) + "th window.")
if verbose:
print(str(i) + "th fragment:")
print(data)
current_size += len(fragment_list[i][1])
percent = round(float(current_size) / float(total_size) * 100, 2)
# Send the data.
print("Sending...")
# Convert to a Fragment class for easier manipulation.
fragment = Fragment(profile_uplink, fragment_list[i])
# If a fragment is an All-0 or an All-1:
if fragment.is_all_0() or fragment.is_all_1():
# Configure for downlink reception
the_socket.setsockopt(socket.SOL_SIGFOX, socket.SO_RX, True)
# Set the timeout for RETRANSMISSION_TIMER_VALUE.
the_socket.settimeout(profile_uplink.RETRANSMISSION_TIMER_VALUE)
the_socket.send(data)
print(
str(current_size) + " / " + str(total_size) + ", " + str(percent) +
"%")
# Try receiving an ACK from the receiver.
try:
current_size += len(fragment_list[i][1])
percent = round(float(current_size) / float(total_size) * 100, 2)
# Send the data.
print("Sending...")
# response = send_request(data, profile_uplink.RETRANSMISSION_TIMER_VALUE)
the_socket.sendto(data, address)
print(
str(current_size) + " / " + str(total_size) + ", " + str(percent) +
"%")
# Convert to a Fragment class for easier manipulation.
fragment = Fragment(profile_uplink, fragment_list[i])
# If a fragment is an All-0 or an All-1:
if retransmitting or fragment.is_all_0() or fragment.is_all_1():
# Juan Carlos dijo que al enviar un ACKREQ el contador se reinicia.
attempts = 0
# Set the timeout for RETRANSMISSION_TIMER_VALUE.
# the_socket.settimeout(profile_uplink.RETRANSMISSION_TIMER_VALUE)
while attempts < profile_uplink.MAX_ACK_REQUESTS:
# Try receiving an ACK from the receiver.
try:
# ack = response
ack, address = the_socket.recvfrom(profile_downlink.MTU)
print('ACK -> {}'.format(ack))
print("ACK received. - {}".format(ack.decode()))
def receiver():
"""HTTP Cloud Function.
Args:
request (flask.Request): The request object.
<http://flask.pocoo.org/docs/1.0/api/#flask.Request>
Returns:
The response text, or any set of values that can be turned into a
Response object using `make_response`
<http://flask.pocoo.org/docs/1.0/api/#flask.Flask.make_response>.
"""
# File where we will store authentication credentials after acquiring them.
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = config.CLIENT_SECRETS_FILE
# Wait for an HTTP POST request.
if request.method == 'POST':
# Get request JSON.
print("POST RECEIVED")
request_dict = request.get_json()
print('Received Sigfox message: {}'.format(request_dict))
# Get data and Sigfox Sequence Number.
fragment = request_dict["data"]
sigfox_sequence_number = request_dict["seqNumber"]
header_first_hex = fragment[0]
if header_first_hex == '0' or header_first_hex == '1':
header = bytes.fromhex(fragment[:2])
payload = bytearray.fromhex(fragment[2:])
header_bytes = 1
elif header_first_hex == 'f' or header_first_hex == '2':
header = bytearray.fromhex(fragment[:4])
payload = bytearray.fromhex(fragment[4:])
header_bytes = 2
else:
print("Wrong header in fragment")
return 'wrong header', 204
data = [header, payload]
# Initialize SCHC variables.
profile = SigfoxProfile("UPLINK", "ACK ON ERROR", header_bytes)
buffer_size = profile.UPLINK_MTU
n = profile.N
m = profile.M
# If fragment size is greater than buffer size, ignore it and end function.
if len(fragment
) / 2 * 8 > buffer_size: # Fragment is hex, 1 hex = 1/2 byte
return json.dumps(
{"message":
"Fragment size is greater than buffer size D:"}), 200
# Initialize empty window
window = []
for i in range(2**n - 1):
window.append([b"", b""])
# Compute the fragment compressed number (FCN) from the Profile
fcn_dict = {}
for j in range(2**n - 1):
fcn_dict[zfill(bin((2**n - 2) - (j % (2**n - 1)))[2:], n)] = j
# Convert to a Fragment class for easier manipulation.
fragment_message = Fragment(profile, data)
# Get current window for this fragment.
current_window = int(fragment_message.HEADER.W, 2)
# Get the current bitmap.
bitmap = read_blob("all_windows/window_%d/bitmap_%d" %
(current_window, current_window))
if fragment_message.is_sender_abort():
print("Sender-Abort received")
return 'Sender-Abort received', 204
try:
fragment_number = fcn_dict[fragment_message.HEADER.FCN]
upload_blob(fragment_number, "fragment_number")
time_received = int(request_dict["time"])
if exists_blob("timestamp"):
# Check time validation.
last_time_received = int(read_blob("timestamp"))
# If this is not the very first fragment and the inactivity timer has been reached, ignore the message.
if str(fragment_number) != "0" and str(
current_window
) != "0" and time_received - last_time_received > profile.INACTIVITY_TIMER_VALUE:
print("[RECV] Inactivity timer reached. Ending session.")
receiver_abort = ReceiverAbort(profile,
fragment_message.HEADER)
print("Sending Receiver Abort")
response_json = send_ack(request_dict, receiver_abort)
print(f"Response content -> {response_json}")
return response_json, 200
# Upload current timestamp.
upload_blob(time_received, "timestamp")
# Print some data for the user.
print(
f"[RECV] This corresponds to the {ordinal(fragment_number)} fragment "
f"of the {ordinal(current_window)} window.")
print(f"[RECV] Sigfox sequence number: {sigfox_sequence_number}")
# Update bitmap and upload it.
bitmap = replace_bit(bitmap, fragment_number, '1')
# If the FCN could not been found, it almost certainly is the final fragment.
except KeyError:
print("[RECV] This seems to be the final fragment.")
fragment_number = profile.WINDOW_SIZE - 1
# Upload current timestamp.
time_received = int(request_dict["time"])
upload_blob(time_received, "timestamp")
print(
f"is All-1:{fragment_message.is_all_1()}, is All-0:{fragment_message.is_all_0()}"
)
# Update bitmap and upload it.
bitmap = replace_bit(bitmap, len(bitmap) - 1, '1')
# Upload the fragment data.
upload_blob(
bitmap,
f"all_windows/window_{current_window}/bitmap_{current_window}")
upload_blob(
data[0].decode("ISO-8859-1") + data[1].decode("utf-8"),
f"all_windows/window_{current_window}/fragment_{current_window}_{fragment_number}"
)
# Get some SCHC values from the fragment.
rule_id = fragment_message.HEADER.RULE_ID
dtag = fragment_message.HEADER.DTAG
# Get last and current Sigfox sequence number (SSN)
last_sequence_number = 0
if exists_blob("SSN"):
last_sequence_number = read_blob("SSN")
upload_blob(sigfox_sequence_number, "SSN")
# # Controlling deterministic losses. This loads the file "loss_mask.txt" which states when should a fragment be
# # lost, separated by windows.
# fd = None
# try:
# fd = open(config.LOSS_MASK_MODIFIED, "r")
# except FileNotFoundError:
# fd = open(config.LOSS_MASK, "r")
# finally:
# loss_mask = []
# for line in fd:
# if not line.startswith("#"):
# for char in line:
# try:
# loss_mask.append(int(char))
# except ValueError:
# pass
# fd.close()
#
# print(f"Loss mask: {loss_mask}")
# If the fragment is at the end of a window (ALL-0 or ALL-1)
if fragment_message.is_all_0() or fragment_message.is_all_1():
# Prepare the ACK bitmap. Find the first bitmap with a 0 in it.
for i in range(current_window + 1):
bitmap_ack = read_blob("all_windows/window_%d/bitmap_%d" %
(i, i))
print(bitmap_ack)
window_ack = i
if '0' in bitmap_ack:
break
# If the ACK bitmap has a 0 at the end of a non-final window, a fragment has been lost.
if fragment_message.is_all_0() and '0' in bitmap_ack:
print("[ALL0] Sending ACK for lost fragments...")
print("bitmap with errors -> {}".format(bitmap_ack))
# Create an ACK message and send it.
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
print("Response content -> {}".format(response_json))
return response_json, 200
# If the ACK bitmap is complete and the fragment is an ALL-0, don't send an ACK
if fragment_message.is_all_0() and bitmap[0] == '1' and all(
bitmap):
print("[ALL0] All Fragments of current window received")
print("[ALL0] No need to send an ACK")
return '', 204
# If the fragment is an ALL-1
if fragment_message.is_all_1():
# The bitmap in the last window follows the following regular expression: "1*0*1*"
# Since the ALL-1, if received, changes the least significant bit of the bitmap.
# For a "complete" bitmap in the last window, there shouldn't be non-consecutive zeroes:
# 1110001 is a valid bitmap, 1101001 is not.
pattern = re.compile("1*0*1")
# If the bitmap matches the regex, check if the last two received fragments are consecutive.
if pattern.fullmatch(bitmap_ack):
print("SSN is {} and last SSN is {}".format(
sigfox_sequence_number, last_sequence_number))
# If the last two received fragments are consecutive, accept the ALL-1 and start reassembling
if int(sigfox_sequence_number) - int(
last_sequence_number) == 1:
last_index = profile.WINDOW_SIZE - 1
print(
"Info for reassemble: last_index:{}, current_window:{}"
.format(last_index, current_window))
print('Activating reassembly process...')
start_request(url=config.LOCAL_REASSEMBLE_URL,
body={
"current_window": current_window,
"header_bytes": header_bytes
})
# Send last ACK to end communication.
print("[ALL1] Reassembled: Sending last ACK")
bitmap = ''
for k in range(profile.BITMAP_SIZE):
bitmap += '0'
last_ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='1',
bitmap=bitmap)
response_json = send_ack(request_dict, last_ack)
# return response_json, 200
# response_json = send_ack(request_dict, last_ack)
print("200, Response content -> {}".format(
response_json))
return response_json, 200
else:
# Send NACK at the end of the window.
print(
"[ALLX] Sending NACK for lost fragments because of SSN..."
)
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
return response_json, 200
# If they are not, there is a gap between two fragments: a fragment has been lost.
# The same happens if the bitmap doesn't match the regex.
else:
# Send NACK at the end of the window.
print("[ALLX] Sending NACK for lost fragments...")
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
return response_json, 200
return '', 204
else:
print(
'Invalid HTTP Method to invoke Cloud Function. Only POST supported'
)
return abort(405)
def schc_receiver():
"""HTTP Cloud Function.
Args:
request (flask.Request): The request object.
<http://flask.pocoo.org/docs/1.0/api/#flask.Request>
Returns:
The response text, or any set of values that can be turned into a
Response object using `make_response`
<http://flask.pocoo.org/docs/1.0/api/#flask.Flask.make_response>.
"""
REASSEMBLER_URL = "http://localhost:5000/reassemble"
CLEANUP_URL = "http://localhost:5000/cleanup"
# File where we will store authentication credentials after acquiring them.
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = config.CLIENT_SECRETS_FILE
# Wait for an HTTP POST request.
if request.method == 'POST':
# Get request JSON.
print("POST RECEIVED")
request_dict = request.get_json()
print('Received Sigfox message: {}'.format(request_dict))
# Get data and Sigfox Sequence Number.
raw_data = request_dict["data"]
sigfox_sequence_number = request_dict["seqNumber"]
ack_req = request_dict["ack"]
# Initialize Cloud Storage variables.
BUCKET_NAME = config.BUCKET_NAME
header_first_hex = raw_data[:1]
if header_first_hex == '0' or header_first_hex == '1':
header = bytes.fromhex(raw_data[:2])
payload = bytearray.fromhex(raw_data[2:])
header_bytes = 1
elif header_first_hex == '2':
header = bytearray.fromhex(raw_data[:4])
payload = bytearray.fromhex(raw_data[4:])
header_bytes = 2
else:
print("Wrong header in raw_data")
return 'wrong header', 204
# Initialize SCHC variables.
profile = Sigfox("UPLINK", "ACK ON ERROR", header_bytes)
n = profile.N
m = profile.M
# If fragment size is greater than buffer size, ignore it and end function.
if len(
raw_data
) / 2 * 8 > profile.UPLINK_MTU: # Fragment is hex, 1 hex = 1/2 byte
return json.dumps(
{"message": "Fragment size is greater than buffer size"}), 200
# If the folder named "all windows" does not exist, create it along with all subdirectories.
initialize_blobs(BUCKET_NAME, profile)
# Compute the fragment compressed number (FCN) from the Profile
fcn_dict = {}
for j in range(2**n - 1):
fcn_dict[zfill(bin((2**n - 2) - (j % (2**n - 1)))[2:], 3)] = j
# Parse raw_data into "data = [header, payload]
# Convert to a Fragment class for easier manipulation.
header = bytes.fromhex(raw_data[:2])
payload = bytearray.fromhex(raw_data[2:])
data = [header, payload]
fragment_message = Fragment(profile, data)
if fragment_message.is_sender_abort():
print("Sender-Abort received")
try:
print("Cleaning")
_ = requests.post(url=CLEANUP_URL,
json={"header_bytes": header_bytes},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
return 'Sender-Abort received', 204
# Get data from this fragment.
fcn = fragment_message.HEADER.FCN
rule_id = fragment_message.HEADER.RULE_ID
dtag = fragment_message.HEADER.DTAG
current_window = int(fragment_message.HEADER.W, 2)
# Get the current bitmap.
bitmap = read_blob(
BUCKET_NAME,
f"all_windows/window_{current_window}/bitmap_{current_window}")
# Controlling deterministic losses. This loads the file "loss_mask.txt" which states when should a fragment be
# lost, separated by windows.
fd = None
try:
fd = open(config.LOSS_MASK_MODIFIED, "r")
except FileNotFoundError:
fd = open(config.LOSS_MASK, "r")
finally:
loss_mask = []
for line in fd:
if not line.startswith("#"):
for char in line:
try:
loss_mask.append(int(char))
except ValueError:
pass
fd.close()
print(f"Loss mask: {loss_mask}")
# Controlling random losses.
if 'enable_losses' in request_dict and not (
fragment_message.is_all_0() or fragment_message.is_all_1()):
if request_dict['enable_losses']:
loss_rate = request_dict["loss_rate"]
# loss_rate = 10
coin = random.random()
print(f'loss rate: {loss_rate}, random toss:{coin * 100}')
if coin * 100 < loss_rate:
print("[LOSS] The fragment was lost.")
return 'fragment lost', 204
# Check if the fragment is an All-1
if is_monochar(fcn) and fcn[0] == '1':
print("[RECV] This is an All-1.")
# Check if fragment is to be lost (All-1 is the very last fragment)
if loss_mask[-1] != 0:
loss_mask[-1] -= 1
with open("loss_mask_modified.txt", "w") as fd:
for i in loss_mask:
fd.write(str(i))
print(f"[RECV] Fragment lost.")
return 'fragment lost', 204
# Inactivity timer validation
time_received = int(request_dict["time"])
if exists_blob(BUCKET_NAME, "timestamp"):
# Check time validation.
last_time_received = int(read_blob(BUCKET_NAME, "timestamp"))
print(f"[RECV] Previous timestamp: {last_time_received}")
print(f"[RECV] This timestamp: {time_received}")
# If the inactivity timer has been reached, abort communication.
if time_received - last_time_received > profile.INACTIVITY_TIMER_VALUE:
print("[RECV] Inactivity timer reached. Ending session.")
receiver_abort = ReceiverAbort(profile,
fragment_message.HEADER)
print("Sending Receiver Abort")
response_json = send_ack(request_dict, receiver_abort)
print(f"Response content -> {response_json}")
try:
print("Cleaning... Inactivity timer reached")
_ = requests.post(url=CLEANUP_URL,
json={"header_bytes": header_bytes},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
return response_json, 200
# Update timestamp
upload_blob(BUCKET_NAME, time_received, "timestamp")
# Update bitmap and upload it.
bitmap = replace_bit(bitmap, len(bitmap) - 1, '1')
print(f"Bitmap is now {bitmap}")
upload_blob(
BUCKET_NAME, bitmap,
f"all_windows/window_{current_window}/bitmap_{current_window}")
# Upload the fragment data.
upload_blob(
BUCKET_NAME, data[0].decode("utf-8") + data[1].decode("utf-8"),
f"all_windows/window_{current_window}/fragment_{current_window}_{profile.WINDOW_SIZE - 1}"
)
# Else, it is a normal fragment.
else:
fragment_number = fcn_dict[fragment_message.HEADER.FCN]
# Check if fragment is to be lost
position = current_window * profile.WINDOW_SIZE + fragment_number
if loss_mask[position] != 0:
loss_mask[position] -= 1
with open(config.LOSS_MASK_MODIFIED, "w") as fd:
for i in loss_mask:
fd.write(str(i))
print(f"[RECV] Fragment lost.")
return 'fragment lost', 204
# Inactivity timer validation
time_received = int(request_dict["time"])
if exists_blob(BUCKET_NAME, "timestamp"):
# Check time validation.
last_time_received = int(read_blob(BUCKET_NAME, "timestamp"))
print(f"[RECV] Previous timestamp: {last_time_received}")
print(f"[RECV] This timestamp: {time_received}")
# If the inactivity timer has been reached, abort communication.
if time_received - last_time_received > profile.INACTIVITY_TIMER_VALUE:
print("[RECV] Inactivity timer reached. Ending session.")
receiver_abort = ReceiverAbort(profile,
fragment_message.HEADER)
print("Sending Receiver Abort")
response_json = send_ack(request_dict, receiver_abort)
print(f"Response content -> {response_json}")
try:
_ = requests.post(url=CLEANUP_URL,
json={"header_bytes": header_bytes},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
return response_json, 200
# Update timestamp
upload_blob(BUCKET_NAME, time_received, "timestamp")
# Update Sigfox sequence number JSON
sequence_numbers = json.loads(read_blob(BUCKET_NAME, "SSN"))
sequence_numbers[position] = request_dict["seqNumber"]
print(sequence_numbers)
upload_blob(BUCKET_NAME, json.dumps(sequence_numbers), "SSN")
upload_blob(BUCKET_NAME, fragment_number, "fragment_number")
# Print some data for the user.
print(
f"[RECV] This corresponds to the {str(fragment_number)}th fragment "
f"of the {str(current_window)}th window.")
print(
f"[RECV] Sigfox sequence number: {str(sigfox_sequence_number)}"
)
# Update bitmap and upload it.
bitmap = replace_bit(bitmap, fragment_number, '1')
print(f"Bitmap is now {bitmap}")
upload_blob(
BUCKET_NAME, bitmap,
f"all_windows/window_{current_window}/bitmap_{current_window}")
# Upload the fragment data.
upload_blob(
BUCKET_NAME, data[0].decode("utf-8") + data[1].decode("utf-8"),
f"all_windows/window_{current_window}/fragment_{current_window}_{fragment_number}"
)
# If the fragment requests an ACK...
if ack_req == "true":
# Prepare the ACK bitmap. Find the first bitmap with a 0 in it.
# This bitmap corresponds to the lowest-numered window with losses.
bitmap_ack = None
window_ack = None
for i in range(current_window + 1):
bitmap_ack = read_blob(BUCKET_NAME,
f"all_windows/window_{i}/bitmap_{i}")
print(bitmap_ack)
window_ack = i
if '0' in bitmap_ack:
break
# The final window is only accessible through All-1.
# If All-0, check non-final windows
if fragment_message.is_all_0():
# If the ACK bitmap has a 0 at a non-final window, a fragment has been lost.
if '0' in bitmap_ack:
print(
"[ALL0] Lost fragments have been detected. Preparing ACK."
)
print(f"[ALL0] Bitmap with errors -> {bitmap_ack}")
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
print(f"Response content -> {response_json}")
print("[ALL0] ACK sent.")
return response_json, 200
# If all bitmaps are complete up to this point, no losses are detected.
else:
print("[ALL0] No losses have been detected.")
print("Response content -> ''")
return '', 204
# If the fragment is All-1, the last window should be considered.
if fragment_message.is_all_1():
# First check for 0s in the bitmap. If the bitmap is of a non-final window, send corresponding ACK.
if current_window != window_ack and '0' in bitmap_ack:
print(
"[ALL1] Lost fragments have been detected. Preparing ACK."
)
print(f"[ALL1] Bitmap with errors -> {bitmap_ack}")
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
print(f"Response content -> {response_json}")
print("[ALL1] ACK sent.")
return response_json, 200
# If the bitmap is of the final window, check the following regex.
else:
# The bitmap in the last window follows the following regular expression: "1*0*1*"
# Since the ALL-1, if received, changes the least significant bit of the bitmap.
# For a "complete" bitmap in the last window, there shouldn't be non-consecutive zeroes:
# 1110001 is a valid bitmap, 1101001 is not.
# The bitmap may or may not contain the 0s.
pattern = re.compile("1*0*1")
# If the bitmap matches the regex, check if there are still lost fragments.
if pattern.fullmatch(bitmap_ack) is not None:
# The idea is the following:
# Assume a fragment has been lost, but the regex has been matched.
# For example, we want a bitmap 1111111 but due to a loss we have 1111101.
# This incomplete bitmap matches the regex.
# We should note that here the SSN of the All-1 and the penultimate fragment received
# are not consecutive.
# Retransmitting the lost fragment and resending the All-1 solves that problem.
# There is another problematic case: we want a bitmap 1111111 but due to losses we have 1111001.
# If the second of those two lost fragments is retransmitted, the new bitmap, 1111011, does not
# match the regex. If, instead, the first of those fragments is retransmitted, the new bitmap
# 1111101 does match the regex. As the sender should retransmit these messages sequentially,
# the SSN of the resent All-1 and the penultimate fragment are still not consecutive.
# The only way for these two SSNs to be consecutive in these cases
# is that the penultimate fragment fills the bitmap in the 6th bit,
# and the last fragment is the All-1.
# This reasoning is still valid when the last window does not contain WINDOW_SIZE fragments.
# These particular cases validate the use for this regex matching.
# Remember that 1111011 is NOT a valid bitmap.
# In conclusion, AFTER the regex matching,
# we should check if the SSNs of the two last received fragments are consecutive.
# The second to last fragment has the highest SSN registered in the JSON.
# TODO: What happens when the All-0 prior to the last window is lost and is retransmitted with the All-1?
# We should consider only the SSNs of the last window. If there is a retransmission in a window
# prior to the last, the reasoning fails since the All-1 is always consecutive to a
# retransmitted fragment of a non-final window.
# If the All-1 is the only fragment of the last window (bitmap 0000001), and bitmap check of
# prior windows has passed, check the consecutiveness of the last All-0 and the All-1.
sequence_numbers = json.loads(
read_blob(BUCKET_NAME, "SSN"))
# This array has the SSNs of the last window.
# last_window_ssn = list(sequence_numbers.values())[current_window * profile.WINDOW_SIZE + 1:]
# If this array is empty, no messages have been received in the last window. Check if the
# last All-0 and the All-1 are consecutive. If they are not, there are lost fragments. If they
# are, the All-0 may have been retransmitted.
# print(last_window_ssn)
# The last sequence number should be the highest of these values.
last_sequence_number = max(
list(map(int, list(sequence_numbers.values()))))
# TODO: If the All-0 has the highest of these values, it may have been retransmitted using the All-1
print(
f"All-1 sequence number {sigfox_sequence_number}")
print(f"Last sequence number {last_sequence_number}")
if int(sigfox_sequence_number) - int(
last_sequence_number) == 1:
# All-1 does not define a fragment number, so its fragment number must be the next
# of the higest registered fragment number.
last_index = (max(
list(map(int, list(sequence_numbers.keys()))))
+ 1) % profile.WINDOW_SIZE
upload_blob(
BUCKET_NAME, data[0].decode("ISO-8859-1") +
data[1].decode("utf-8"),
f"all_windows/window_{current_window}/"
f"fragment_{current_window}_{last_index}")
print(
"[ALL1] Integrity checking complete, launching reassembler."
)
try:
_ = requests.post(url=REASSEMBLER_URL,
json={
"last_index": last_index,
"current_window":
current_window,
"header_bytes":
header_bytes
},
timeout=0.1)
except requests.exceptions.ReadTimeout:
pass
# Send last ACK to end communication (on receiving an All-1, if no fragments are lost,
# if it has received at least one tile, return an ACK for the highest numbered window we
# currently have tiles for).
print("[ALL1] Preparing last ACK")
bitmap = ''
for k in range(profile.BITMAP_SIZE):
bitmap += '0'
last_ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='1',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, last_ack)
print(f"200, Response content -> {response_json}")
print("[ALL1] Last ACK has been sent.")
return response_json, 200
# If the last two fragments are not consecutive, or the bitmap didn't match the regex,
# send an ACK reporting losses.
else:
# Send NACK at the end of the window.
print("[ALLX] Sending NACK for lost fragments...")
ack = ACK(profile=profile,
rule_id=rule_id,
dtag=dtag,
w=zfill(format(window_ack, 'b'), m),
c='0',
bitmap=bitmap_ack)
response_json = send_ack(request_dict, ack)
return response_json, 200
return '', 204
else:
print(
'Invalid HTTP Method to invoke Cloud Function. Only POST supported'
)
return abort(405)