Refactor global vars into appropriate classes
This commit is contained in:
Dan Williams
parent
6d7e1dcb4c
commit
093667d253
@ -10,15 +10,6 @@ pygtk.require('2.0')
|
||||
import gtk, gobject
|
||||
|
||||
|
||||
_MTU = 481
|
||||
_HEADER_LEN = 31
|
||||
_MAGIC = 0xbaea4304
|
||||
_TTL = 120 # 2 minutes
|
||||
|
||||
# Message segment packet types
|
||||
_SEGMENT_TYPE_DATA = 0
|
||||
_SEGMENT_TYPE_RETRANSMIT = 1
|
||||
|
||||
def _stringify_sha(sha):
|
||||
print_sha = ""
|
||||
for char in sha:
|
||||
@ -31,6 +22,8 @@ def _sha_data(data):
|
||||
return sha_hash.digest()
|
||||
|
||||
class MessageSegment(object):
|
||||
_MAGIC = 0xbaea4304
|
||||
|
||||
# 4: magic (0xbaea4304)
|
||||
# 1: type
|
||||
# 2: segment number
|
||||
@ -38,6 +31,38 @@ class MessageSegment(object):
|
||||
# 2: message sequence number
|
||||
#20: total data sha1
|
||||
_HEADER_TEMPLATE = "! IbHHH20s"
|
||||
_HEADER_LEN = struct.calcsize(_HEADER_TEMPLATE)
|
||||
_MTU = 512 - _HEADER_LEN
|
||||
|
||||
# Message segment packet types
|
||||
_SEGMENT_TYPE_DATA = 0
|
||||
_SEGMENT_TYPE_RETRANSMIT = 1
|
||||
|
||||
def is_data_type(stype):
|
||||
if stype == MessageSegment._SEGMENT_TYPE_DATA:
|
||||
return True
|
||||
return False
|
||||
is_data_type = staticmethod(is_data_type)
|
||||
|
||||
def is_retransmit_type(stype):
|
||||
if stype == MessageSegment._SEGMENT_TYPE_RETRANSMIT:
|
||||
return True
|
||||
return False
|
||||
is_retransmit_type = staticmethod(is_retransmit_type)
|
||||
|
||||
def header_len():
|
||||
return MessageSegment._HEADER_LEN
|
||||
header_len = staticmethod(header_len)
|
||||
|
||||
def mtu():
|
||||
return MessageSegment._MTU
|
||||
mtu = staticmethod(mtu)
|
||||
|
||||
def is_type_valid(stype):
|
||||
if MessageSegment.is_data_type(stype) or MessageSegment.is_retransmit_type(stype):
|
||||
return True
|
||||
return False
|
||||
is_type_valid = staticmethod(is_type_valid)
|
||||
|
||||
def _new_from_parts(self, msg_seq_num, segno, total_segs, data, master_sha):
|
||||
"""Construct a new message segment from individual attributes."""
|
||||
@ -61,15 +86,15 @@ class MessageSegment(object):
|
||||
self._total_segs = total_segs
|
||||
self._msg_seq_num = msg_seq_num
|
||||
self._addr = None
|
||||
self._type = _SEGMENT_TYPE_DATA
|
||||
self._type = MessageSegment._SEGMENT_TYPE_DATA
|
||||
|
||||
# Make the header
|
||||
self._header = struct.pack(self._HEADER_TEMPLATE, _MAGIC, self._type,
|
||||
self._header = struct.pack(self._HEADER_TEMPLATE, self._MAGIC, self._type,
|
||||
self._segno, self._total_segs, self._msg_seq_num, self._master_sha)
|
||||
|
||||
def _new_from_data(self, addr, data):
|
||||
"""Verify and construct a new message segment from network data."""
|
||||
if len(data) < _HEADER_LEN + 1:
|
||||
if len(data) < self._HEADER_LEN + 1:
|
||||
raise ValueError("Segment is less then minimum required length")
|
||||
stream = StringIO.StringIO(data)
|
||||
self._stime = None
|
||||
@ -86,17 +111,17 @@ class MessageSegment(object):
|
||||
stream.read(header_size))
|
||||
|
||||
# Sanity checks on the message attributes
|
||||
if seg_type != _SEGMENT_TYPE_DATA and seg_type != _SEGMENT_TYPE_RETRANSMIT:
|
||||
if not MessageSegment.is_type_valid(seg_type):
|
||||
raise ValueError("Segment has invalid type.")
|
||||
if seg_type == _SEGMENT_TYPE_RETRANSMIT:
|
||||
if MessageSegment.is_data_type(seg_type):
|
||||
if segno != 1 or total_segs != 1:
|
||||
raise ValueError("Retransmission request messages must have only one segment.")
|
||||
if magic != _MAGIC:
|
||||
if magic != self._MAGIC:
|
||||
raise ValueError("Segment does not have the correct magic.")
|
||||
if self._data_len < 1:
|
||||
raise ValueError("Segment must have some data.")
|
||||
if self._data_len > _MTU:
|
||||
raise ValueError("Data length must not be larger than the MTU (%s)." % _MTU)
|
||||
if self._data_len > self._MTU:
|
||||
raise ValueError("Data length must not be larger than the MTU (%s)." % self._MTU)
|
||||
if segno < 1:
|
||||
raise ValueError("Segment number must be greater than 0.")
|
||||
if segno > total_segs:
|
||||
@ -161,6 +186,9 @@ class MostlyReliablePipe(object):
|
||||
"""Implement Mostly-Reliable UDP. We don't actually care about guaranteeing
|
||||
delivery or receipt, just a better effort than no effort at all."""
|
||||
|
||||
_UDP_MSG_SIZE = MessageSegment.mtu() + MessageSegment.header_len()
|
||||
_SEGMENT_TTL = 120 # 2 minutes
|
||||
|
||||
def __init__(self, local_addr, remote_addr, port, data_cb, user_data=None):
|
||||
self._local_addr = local_addr
|
||||
self._remote_addr = remote_addr
|
||||
@ -208,7 +236,7 @@ class MostlyReliablePipe(object):
|
||||
|
||||
# Watch the listener socket for data
|
||||
gobject.io_add_watch(self._listen_sock, gobject.IO_IN, self._handle_incoming_data)
|
||||
gobject.timeout_add(120000, self._segment_ttl_worker)
|
||||
gobject.timeout_add(self._SEGMENT_TTL * 1000, self._segment_ttl_worker)
|
||||
|
||||
self._started = True
|
||||
|
||||
@ -216,7 +244,7 @@ class MostlyReliablePipe(object):
|
||||
"""Cull already-sent message segments that are past their TTL."""
|
||||
now = time.time()
|
||||
for segment in self._sent[:]:
|
||||
if segment.stime() < now - _MSG_TTL:
|
||||
if segment.stime() < now - self._SEGMENT_TTL:
|
||||
self._sent.remove(segment)
|
||||
return True
|
||||
|
||||
@ -271,10 +299,10 @@ class MostlyReliablePipe(object):
|
||||
# 20: total data sha1
|
||||
# 2: segment number
|
||||
data = segment.data()
|
||||
if len(data) != 22:
|
||||
template = "@ H20sH"
|
||||
if len(data) != struct.calcsize(template):
|
||||
print "Bad retransmission request message format."
|
||||
# Native byte-order since the receive bits already unpacked it for us
|
||||
template = "@ H20sH"
|
||||
(msg_seq_num, master_sha, segno) = struct.unpack(template, data)
|
||||
|
||||
def _handle_incoming_data(self, source, condition):
|
||||
@ -283,12 +311,13 @@ class MostlyReliablePipe(object):
|
||||
if not (condition & gobject.IO_IN):
|
||||
return True
|
||||
msg = {}
|
||||
data, addr = source.recvfrom(_MTU + _HEADER_LEN)
|
||||
data, addr = source.recvfrom(self._UDP_MSG_SIZE)
|
||||
try:
|
||||
segment = MessageSegment.new_from_data(addr, data)
|
||||
if segment.segment_type() == _SEGMENT_TYPE_DATA:
|
||||
stype = segment.segment_type()
|
||||
if MessageSegment.is_data_type(stype):
|
||||
self._process_incoming_data(segment)
|
||||
elif segment.segment_type() == _SEGMENT_TYPE_RETRANSMIT:
|
||||
elif MessageSegment.is_retransmit_type(stype):
|
||||
self._process_retransmit_request(segment)
|
||||
except ValueError, exc:
|
||||
print "Bad segment: %s" % exc
|
||||
@ -310,17 +339,18 @@ class MostlyReliablePipe(object):
|
||||
|
||||
# Split up the data into segments
|
||||
left = length = len(data)
|
||||
nmessages = length / _MTU
|
||||
if length % _MTU > 0:
|
||||
mtu = MessageSegment.mtu()
|
||||
nmessages = length / mtu
|
||||
if length % mtu > 0:
|
||||
nmessages = nmessages + 1
|
||||
msg_num = 1
|
||||
while left > 0:
|
||||
msg = MessageSegment.new_from_parts(self._seq_counter, msg_num,
|
||||
nmessages, data[:_MTU], master_sha)
|
||||
nmessages, data[:mtu], master_sha)
|
||||
self._outgoing.append(msg)
|
||||
msg_num = msg_num + 1
|
||||
data = data[_MTU:]
|
||||
left = left - _MTU
|
||||
data = data[mtu:]
|
||||
left = left - mtu
|
||||
if len(self._outgoing) > 0 and self._worker == 0:
|
||||
self._worker = gobject.idle_add(self._send_worker)
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user