mirror of https://github.com/dirtbags/netarch.git
Major resequencing bugfix + minor fixes
* The resequencer was dropping any data frames after the first FIN/RST. * Make things more Pythony by not changing type checks to try/except * Add an 8-bit-clean caesar implementation to crypto module
This commit is contained in:
Neale Pickett
parent
237fe5910d
commit
e4c37a3a24
20
__init__.py
20
__init__.py
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@ -115,16 +115,7 @@ def assert_in(a, *b):
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class BitVector:
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def __init__(self, i=0, length=None):
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if type(i) == type(1):
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self._val = i
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if length is not None:
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self._len = length
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else:
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self._len = 0
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while i > 0:
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i >>= 1
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self._len += 1
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else:
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try:
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self._val = 0
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for c in i:
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self._val <<= 8
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@ -133,6 +124,15 @@ class BitVector:
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self._len = length
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else:
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self._len = len(i) * 8
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except TypeError:
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self._val = i
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if length is not None:
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self._len = length
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else:
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self._len = 0
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while i > 0:
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i >>= 1
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self._len += 1
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def __len__(self):
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return self._len
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@ -163,7 +163,7 @@ def neighbors(txt):
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##
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def rot(n, txt):
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"""Caesar cipher"""
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"""Caesar cipher only across letters"""
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out = ""
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for c in txt:
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@ -178,8 +178,11 @@ def rot(n, txt):
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return out
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def caesar(n, txt):
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return [chr((ord(c) + n) % 256) for c in txt]
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def caesars(txt):
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return [rot(i, txt) for i in range(26)]
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return [caesar(i, txt) for i in range(256)]
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# Tabula recta
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tabula_recta = caesars('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
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45
gapstr.py
45
gapstr.py
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@ -30,26 +30,29 @@ class GapString:
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self.length += len(i)
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self.contents.append(i)
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except TypeError:
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self.length += int(i)
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self.contents.append(int(i))
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self.length += i
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self.contents.append(long(i))
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def __str__(self):
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ret = []
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for i in self.contents:
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if isinstance(i, int):
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try:
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ret.append(self.drop * i)
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else:
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except TypeError:
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ret.append(i)
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return ''.join(ret)
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def __iter__(self):
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for i in self.contents:
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if isinstance(i, int):
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for j in range(i):
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yield self.drop
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else:
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try:
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for c in i:
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yield c
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except TypeError:
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for j in range(i):
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yield self.drop
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def __nonzero__(self):
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return self.length > 0
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def hasgaps(self):
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for i in self.contents:
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@ -62,10 +65,10 @@ class GapString:
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d = __init__.HexDumper(fd)
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for i in self.contents:
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if isinstance(i, int):
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try:
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for j in range(i):
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d.dump_drop()
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else:
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except TypeError:
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for c in i:
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d.dump_chr(c)
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d.finish()
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@ -90,11 +93,11 @@ class GapString:
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# Trim off the beginning
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while start >= 0:
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i = new.contents.pop(0)
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if isinstance(i, int):
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try:
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start -= i
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if start < 0:
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new.contents.insert(0, -start)
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else:
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except TypeError:
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start -= len(i)
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if start < 0:
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new.contents.insert(0, i[start:])
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@ -102,11 +105,11 @@ class GapString:
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# Trim off the end
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while l >= 0:
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i = new.contents.pop()
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if isinstance(i, int):
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try:
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l -= i
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if l < 0:
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new.contents.append(-l)
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else:
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except TypeError:
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l -= len(i)
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if l < 0:
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new.contents.append(i[:-l])
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@ -127,17 +130,15 @@ class GapString:
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return new
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def __xor__(self, mask):
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if isinstance(mask, int):
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mask = [mask]
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if isinstance(mask, str) or isinstance(mask, GapString):
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try:
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mask = [ord(c) for c in mask]
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except TypeError:
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mask = [mask]
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masklen = len(mask)
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new = self.__class__(drop=self.drop)
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for i in self.contents:
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if isinstance(i, int):
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new.append(i)
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else:
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try:
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r = []
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offset = len(new) % masklen
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for c in i:
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@ -145,8 +146,12 @@ class GapString:
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r.append(chr(o ^ mask[offset]))
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offset = (offset + 1) % masklen
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new.append(''.join(r))
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except TypeError:
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new.append(i)
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return new
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def startswith(self, what):
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return (what == str(self[:len(what)]))
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if __name__ == '__main__':
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24
ip.py
24
ip.py
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@ -23,6 +23,7 @@ def unpack_nybbles(byte):
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IP = 0x0800
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ARP = 0x0806
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VLAN = 0x8100
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ICMP = 1
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TCP = 6
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@ -42,6 +43,8 @@ class Frame:
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self.eth_shost,
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self.eth_type,
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p) = unpack('!6s6sH', frame)
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if self.eth_type == VLAN:
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_, self.eth_type, p = unpack('!HH', p)
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if self.eth_type == ARP:
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# ARP
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self.name, self.protocol = ('ARP', ARP)
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@ -184,7 +187,7 @@ class TCP_Resequence:
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self.lastack = [None, None]
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self.first = None
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self.pending = [{}, {}]
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self.closed = 0
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self.closed = [False, False]
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self.midstream = False
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self.hash = 0
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@ -198,7 +201,7 @@ class TCP_Resequence:
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by __init__. The current value of this function is the state.
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"""
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pass
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raise NotImplementedError()
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def handle_handshake(self, pkt):
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if not self.first:
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@ -237,8 +240,12 @@ class TCP_Resequence:
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# Does this ACK after the last output sequence number?
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seq = self.lastack[idx]
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if pkt.ack > seq:
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if self.closed[idx]:
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# XXX: If the next thing happens, that means you need to
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# return a gapstring to deal with dropped frames
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assert (pkt.ack == seq + 1)
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return
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pending = self.pending[xdi]
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# Get a sorted list of sequence numbers
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keys = pending.keys()
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keys.sort()
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@ -259,7 +266,11 @@ class TCP_Resequence:
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# Hopefully just a retransmit...
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del pending[key]
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continue
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elif key == seq:
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# Default
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pass
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elif key > seq:
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# Dropped frame(s)
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gs.append(key - seq)
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seq = key
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frame = pending[key]
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@ -267,6 +278,7 @@ class TCP_Resequence:
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seq += len(frame.payload)
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del pending[key]
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if seq != pkt.ack:
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# Drop at the end
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gs.append(pkt.ack - seq)
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self.lastack[idx] = pkt.ack
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@ -276,14 +288,12 @@ class TCP_Resequence:
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# Is it a FIN or RST?
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if pkt.flags & (FIN | RST):
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self.lastack[xdi] = pkt.seq + 1
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self.closed += 1
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if self.closed == 2:
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self.closed[idx] = True
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if self.closed == 3:
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# Warn about any unhandled packets
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if self.pending[0] or self.pending[1]:
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warnings.warn('Dropping unhandled frames after shutdown' % pkt)
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self.handle = self.handle_drop
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ret = None
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return ret
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