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Reworked serial interface with HDLC framing instead of timeouts

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This commit is contained in:
Mark Qvist 2020-05-06 14:34:03 +02:00
parent 4c3a874b21
commit 67fc7685ec
1 changed files with 39 additions and 11 deletions
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50
RNS/Interfaces/SerialInterface.py
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@ -1,9 +1,3 @@
# TODO: This should be reworked for Python3 support,
# and maybe framing should be introduced to improve
# performance. The current 100ms wait is a bit stupid.
# Probably also need to add queue support like the
# other interfaces.
from .Interface import Interface
from time import sleep
import sys
@ -12,6 +6,17 @@ import threading
import time
import RNS
class HDLC():
FLAG = 0x7E
ESC = 0x7D
ESC_MASK = 0x20
@staticmethod
def escape(data):
data = data.replace(bytes([HDLC.ESC]), bytes([HDLC.ESC, HDLC.ESC^HDLC.ESC_MASK]))
data = data.replace(bytes([HDLC.FLAG]), bytes([HDLC.ESC, HDLC.FLAG^HDLC.ESC_MASK]))
return data
class SerialInterface(Interface):
MAX_CHUNK = 32768
@ -77,6 +82,7 @@ class SerialInterface(Interface):
def processOutgoing(self,data):
if self.online:
data = bytes([HDLC.FLAG])+HDLC.escape(data)+bytes([HDLC.FLAG])
written = self.serial.write(data)
if written != len(data):
raise IOError("Serial interface only wrote "+str(written)+" bytes of "+str(len(data)))
@ -84,18 +90,40 @@ class SerialInterface(Interface):
def readLoop(self):
try:
data_buffer = ""
in_frame = False
escape = False
data_buffer = b""
last_read_ms = int(time.time()*1000)
while self.serial.is_open:
if self.serial.in_waiting:
data = self.serial.read(size=self.serial.in_waiting)
data_buffer += data
byte = ord(self.serial.read(1))
last_read_ms = int(time.time()*1000)
if (in_frame and byte == HDLC.FLAG):
in_frame = False
self.processIncoming(data_buffer)
elif (byte == HDLC.FLAG):
in_frame = True
data_buffer = b""
elif (in_frame and len(data_buffer) < RNS.Reticulum.MTU):
if (byte == HDLC.ESC):
escape = True
else:
if (escape):
if (byte == HDLC.FLAG ^ HDLC.ESC_MASK):
byte = HDLC.FLAG
if (byte == HDLC.ESC ^ HDLC.ESC_MASK):
byte = HDLC.ESC
escape = False
data_buffer = data_buffer+bytes([byte])
else:
time_since_last = int(time.time()*1000) - last_read_ms
if len(data_buffer) > 0 and time_since_last > self.timeout:
self.processIncoming(data_buffer)
data_buffer = ""
data_buffer = b""
in_frame = False
escape = False
sleep(0.08)
except Exception as e:
self.online = False