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netarch
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Simpler logic handles out-of-order packets better

This commit is contained in:
Neale Pickett 2009-04-06 15:17:59 -06:00
parent 90d3a08a36
commit 71787f6b56
1 changed files with 10 additions and 17 deletions
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25
ip.py
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@ -231,12 +231,13 @@ class TCP_Resequence:
self.handle(pkt) self.handle(pkt)
def handle_packet(self, pkt): def handle_packet(self, pkt):
ret = None
# Which way is this going? 0 == from client # Which way is this going? 0 == from client
idx = int(pkt.src == self.srv) idx = int(pkt.src == self.srv)
xdi = 1 - idx xdi = 1 - idx
# Stick it into pending
self.pending[idx][pkt.seq] = pkt
# Does this ACK after the last output sequence number? # Does this ACK after the last output sequence number?
seq = self.lastack[idx] seq = self.lastack[idx]
if pkt.ack > seq: if pkt.ack > seq:
@ -258,7 +259,12 @@ class TCP_Resequence:
if key >= pkt.ack: if key >= pkt.ack:
# In the future # In the future
break break
elif key == seq: if pkt.flags & (FIN | RST):
seq += 1
self.closed[idx] = True
if self.closed == [True, True]:
self.handle = self.handle_drop
if key == seq:
# Default # Default
frame = pending[key] frame = pending[key]
gs.append(frame.payload) gs.append(frame.payload)
@ -282,19 +288,6 @@ class TCP_Resequence:
gs.append(pkt.ack - seq) gs.append(pkt.ack - seq)
self.lastack[idx] = pkt.ack self.lastack[idx] = pkt.ack
# If it has a payload, stick it into pending
if pkt.payload:
self.pending[idx][pkt.seq] = pkt
# Is it a FIN or RST?
if pkt.flags & (FIN | RST):
self.closed[idx] = True
if self.closed == [True, True]:
# Warn about any unhandled packets
if self.pending[0] or self.pending[1]:
warnings.warn('Dropping unhandled frames after shutdown' % pkt)
self.handle = self.handle_drop
return ret return ret
def handle_drop(self, pkt): def handle_drop(self, pkt):