marvin.weiler/python-netfilterqueue
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work on new packet

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dowright 2021-08-23 21:14:42 -07:00 committed by DOWRIGHT
parent 027547be72
commit 3674db7a90
1 changed files with 21 additions and 11 deletions
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32
new_packet.pyx
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@ -42,7 +42,7 @@ cdef class CPacket:
# return "%s packet, %s bytes" % (protocol, self.payload_len)
@staticmethod
cdef nf_callback(self, nfq_q_handle *qh, nfgenmsg *nfmsg, nfq_data *nfa, void *data):
cdef int nf_callback(self, nfq_q_handle *qh, nfgenmsg *nfmsg, nfq_data *nfa, void *data):
# cdef NetfilterQueue nfqueue = <NetfilterQueue > data
# cdef object user_callback = <object > nfqueue.user_callback
@ -50,12 +50,16 @@ cdef class CPacket:
packet = CPacket()
packet.parse(qh, nfa)
return 1
# NOTE: this will be callback target for nfqueue
cdef parse(self, nfq_q_handle *qh, nfq_data *nfa) nogil:
'''Alternate constructor. Used to start listener/proxy instances using nfqueue bindings.'''
'''Assign a packet from NFQ to this object. Parse the header and load local values.'''
cdef readonly unsigned char *data
self._qh = qh
self._nfa = nfa
self._hdr = nfq_get_msg_packet_hdr(nfa)
@ -64,18 +68,18 @@ cdef class CPacket:
# self.hw_protocol = ntohs(self._hdr.hw_protocol)
# self.hook = self._hdr.hook
self.payload_len = nfq_get_payload(self._nfa, & self.data)
self.payload_len = nfq_get_payload(self._nfa, &data)
# TODO: figure this out. cant use no gil if its here.
# if self.payload_len < 0:
# raise OSError("Failed to get payload of packet.")
# timestamp gets assigned via pointer/struct -> time_val: (t_sec, t_usec).
nfq_get_timestamp(self._nfa, & self.timestamp)
nfq_get_timestamp(self._nfa, &self.timestamp)
self._mark = nfq_get_nfmark(nfa)
# splitting packet by tcp/ip layers
cdef int error = self._parse()
self._parse(data)
# if (self.continue_condition):
# self._before_exit()
@ -84,14 +88,12 @@ cdef class CPacket:
# with gil:
# callback(self)
return 0
cdef _parse(self):
cdef _parse(self, readonly unsigned char *data):
'''Index tcp/ip packet layers 3 & 4 for use as instance objects.
the before_exit method will be called before returning, which can be used to create
subclass specific objects like namedtuples or application layer data.'''
cdef iphdr *ip_header = <iphdr*>self.data
cdef iphdr *ip_header = <iphdr*>data
cdef u_int8_t iphdr_len = ip_header.tos & 15 * 4
@ -101,13 +103,21 @@ cdef class CPacket:
if (ip_header.protocol == IPPROTO_TCP):
self.tcp_header = <tcphdr*>self.data[iphdr_len:]
*tcp_header = <tcphdr*>data[iphdr_len:]
self.tcp_header = tcp_header
if (ip_header.protocol == IPPROTO_UDP):
self.udp_header = <udphdr*>self.data[iphdr_len:]
*udp_header = <udphdr*>data[iphdr_len:]
self.udp_header = udp_header
if (ip_header.protocol == IPPROTO_ICMP):
self.icmp_header = <icmphdr*>self.data[iphdr_len:]
*icmp_header = <icmphdr*>data[iphdr_len:]
self.icmp_header = icmp_header
cdef void verdict(self, u_int32_t verdict):
'''Call appropriate set_verdict... function on packet.'''