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Patch 2 #35

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901637a
Update dhcpserver.py
Apr 15, 2021
5a6b482
Update dhcpserver.py
Apr 15, 2021
aae2b8d
Update dhcpserver.py
Apr 21, 2021
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16 changes: 11 additions & 5 deletions ptftplib/dhcpserver.py
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Original file line number Diff line number Diff line change
Expand Up @@ -111,7 +111,7 @@ def _dhcp_options(options):
"""Generate a sequence of DHCP options from a raw byte stream."""
i = 0
while i < len(options):
code = ord(options[i])
code = _ord(options[i])

# Handle pad and end options.
if code == 0:
Expand All @@ -121,7 +121,7 @@ def _dhcp_options(options):
return

# Extract and yield the option number and option value.
data_len = ord(options[i+1])
data_len = _ord(options[i+1])
data = options[i + 2:i + 2 + data_len]
i += 2 + data_len
yield (code, data)
Expand Down Expand Up @@ -161,6 +161,11 @@ class NotDhcpPacketError(Exception):
class UninterestingDhcpPacket(Exception):
"""Packet is DHCP, but not of interest to us."""

def _ord(e):
if type(e) == int:
return e
else:
return ord(e)

class DhcpPacket(object):
def __init__(self, pkt):
Expand All @@ -171,14 +176,15 @@ def __init__(self, pkt):

# Strip off the ethernet frame and check the IP packet type. It should
# be UDP (0x11)
# for python3 it's bytes, need to decode to str first
pkt = pkt[14:]
if ord(pkt[9]) != IP_UDP_PROTO:
if _ord(pkt[9]) != IP_UDP_PROTO:
raise NotDhcpPacketError()

# Strip off the IP header and check the source/destination ports in the
# UDP datagram. The packet should be from port 68 to port 67 to
# tentatively be DHCP.
header_len = (ord(pkt[0]) & 0xF) * 4
header_len = (_ord(pkt[0]) & 0xF) * 4
pkt = pkt[header_len:]
(src, dst) = struct.unpack('!2H', pkt[:4])
if not (src == 68 and dst == 67):
Expand Down Expand Up @@ -206,7 +212,7 @@ def _parse_dhcp_options(self, options):

for option, value in _dhcp_options(options):
if option == DHCP_OPTION_OP:
self.op = ord(value)
self.op = _ord(value)
# We only care about interesting "incoming" DHCP ops.
if self.op not in (DHCP_OP_DHCPDISCOVER, DHCP_OP_DHCPREQUEST):
raise UninterestingDhcpPacket()
Expand Down