def tlsn_msg_receiver(my_nick,counterparty_nick,ack_queue,recv_queue,message_headers,pk,seq_init=100000):
'''Intended to be run as a thread; puts msgs sent to my_nick from counterparty_nick
onto the Queue recv_queue, and sends acknowledgements onto ack_queue, filtering out
messages whose headers/topics are not in message_headers, and using sequence numbering
starting from seq_init (or 0 if seq_init is undef).
Messages are received in chunks and decrypted using private key pk and base64 decoded, then
reassembled according to line endings CRLF and EOL, as per tlsnotary's
messaging protocol.
'''
if not initialized:
raise Exception("TLSN Messaging not yet instantiated")
if not hasattr(tlsn_msg_receiver, 'last_seq_which_i_acked'):
if not seq_init: seq_init=0
tlsn_msg_receiver.last_seq_which_i_acked = seq_init #static variable. Initialized only on first function's run
chunks = []
while True:
eemsg = mi.msg_receiver(my_nick,counterparty_nick)
if not eemsg: continue #note that the timeout is in the implementation layer
#acknowledgements are not our business here; put them on the queue
if eemsg[0].startswith('ack'):
#acks are not encrypted
ack_queue.put(eemsg[0][len('ack:'):])
continue
if len(eemsg) !=3: continue
if not eemsg[0].startswith('seq'): continue #wrong format; old server hellos will do this
msg_decrypted = dd(eemsg[1],pk)
#print ("decrypted message is: ",msg_decrypted)
if len(chunks) == 0:
msg = [msg_decrypted.split(':')[0]] + [':'.join(msg_decrypted.split(':')[1:])]+[eemsg[2]]
else:
msg = [None,msg_decrypted,eemsg[2]]
his_seq = int(eemsg[0][len('seq:'):])
if his_seq <= tlsn_msg_receiver.last_seq_which_i_acked:
#the other side is out of sync, send an ack again
mi.send_raw(' :' + counterparty_nick + ' ack:' + str(his_seq))
continue
#we did not receive the next seq in order
if not his_seq == tlsn_msg_receiver.last_seq_which_i_acked +1: continue
#else we got a new seq
if len(chunks)==0: #a new message is starting
if not msg[0].startswith(message_headers) : continue
hdr = msg[0]
#'CRLF' is used at the end of the first chunk, 'EOL' is used to show that there are no more chunks
chunks.append(msg[1])
mi.send_raw(' :' + counterparty_nick + ' ack:' + str(his_seq))
tlsn_msg_receiver.last_seq_which_i_acked = his_seq
if msg[-1]=='EOL':
assembled_message = ''.join(chunks)
recv_queue.put(hdr+':'+assembled_message)
chunks = []
def tlsn_send_raw(data):
if not initialized:
raise Exception("TLSN Messaging not yet instantiated")
return mi.send_raw(data)
def tlsn_msg_receiver(my_nick,
counterparty_nick,
ack_queue,
recv_queue,
message_headers,
pk,
seq_init=100000):
'''Intended to be run as a thread; puts msgs sent to my_nick from counterparty_nick
onto the Queue recv_queue, and sends acknowledgements onto ack_queue, filtering out
messages whose headers/topics are not in message_headers, and using sequence numbering
starting from seq_init (or 0 if seq_init is undef).
Messages are received in chunks and decrypted using private key pk and base64 decoded, then
reassembled according to line endings CRLF and EOL, as per tlsnotary's
messaging protocol.
'''
if not initialized:
raise Exception("TLSN Messaging not yet instantiated")
if not hasattr(tlsn_msg_receiver, 'last_seq_which_i_acked'):
if not seq_init: seq_init = 0
tlsn_msg_receiver.last_seq_which_i_acked = seq_init #static variable. Initialized only on first function's run
chunks = []
while True:
eemsg = mi.msg_receiver(my_nick, counterparty_nick)
if not eemsg:
continue #note that the timeout is in the implementation layer
#acknowledgements are not our business here; put them on the queue
if eemsg[0].startswith('ack'):
#acks are not encrypted
ack_queue.put(eemsg[0][len('ack:'):])
continue
if len(eemsg) != 3: continue
if not eemsg[0].startswith('seq'):
continue #wrong format; old server hellos will do this
msg_decrypted = dd(eemsg[1], pk)
#print ("decrypted message is: ",msg_decrypted)
if len(chunks) == 0:
msg = [msg_decrypted.split(':')[0]
] + [':'.join(msg_decrypted.split(':')[1:])] + [eemsg[2]]
else:
msg = [None, msg_decrypted, eemsg[2]]
his_seq = int(eemsg[0][len('seq:'):])
if his_seq <= tlsn_msg_receiver.last_seq_which_i_acked:
#the other side is out of sync, send an ack again
mi.send_raw(' :' + counterparty_nick + ' ack:' + str(his_seq))
continue
#we did not receive the next seq in order
if not his_seq == tlsn_msg_receiver.last_seq_which_i_acked + 1:
continue
#else we got a new seq
if len(chunks) == 0: #a new message is starting
if not msg[0].startswith(message_headers): continue
hdr = msg[0]
#'CRLF' is used at the end of the first chunk, 'EOL' is used to show that there are no more chunks
chunks.append(msg[1])
mi.send_raw(' :' + counterparty_nick + ' ack:' + str(his_seq))
tlsn_msg_receiver.last_seq_which_i_acked = his_seq
if msg[-1] == 'EOL':
assembled_message = ''.join(chunks)
recv_queue.put(hdr + ':' + assembled_message)
chunks = []
def tlsn_send_raw(data):
if not initialized:
raise Exception("TLSN Messaging not yet instantiated")
return mi.send_raw(data)
