new_contents: import ctypes
  import threading
  import sys
  import os
  import errno
  
  
  OSX_PCAP_DYLIB = '/usr/lib/libpcap.A.dylib'
  OSX_LIBC_DYLIB = '/usr/lib/libSystem.B.dylib'
  PCAP_ERRBUF_SIZE = 256
  packet_count_limit = ctypes.c_int(1)
  timeout_limit = ctypes.c_int(1000) # In milliseconds 
  err_buf = ctypes.create_string_buffer(PCAP_ERRBUF_SIZE)
  
  class bpf_program(ctypes.Structure):
      _fields_ = [("bf_len", ctypes.c_int),("bf_insns", ctypes.c_void_p)]
  
  class pcap_pkthdr(ctypes.Structure):
      _fields_ = [("tv_sec", ctypes.c_long), ("tv_usec", ctypes.c_long), ("caplen", ctypes.c_uint), ("len", ctypes.c_uint)]
  
  class pcap_stat(ctypes.Structure):
      _fields_ = [("ps_recv",ctypes.c_uint), ("ps_drop",ctypes.c_uint), ("ps_ifdrop", ctypes.c_int)]
  
  def pkthandler(pkthdr,packet):
      print("In callback:")
      print("pkthdr[0:7]:",pkthdr.contents.len)
      print(pkthdr.contents.tv_sec,pkthdr.contents.caplen,pkthdr.contents.len)
      print(packet.contents[:10])
      print()
  
  print "-------------------------------------------"
  libc = ctypes.CDLL(OSX_LIBC_DYLIB, use_errno=True)
  if not libc:
      print "Error loading C libary: %s" % errno.errorcode[ctypes.get_errno()]
  print "* C runtime libary loaded: %s" % OSX_LIBC_DYLIB
  pcap = ctypes.CDLL(OSX_PCAP_DYLIB, use_errno=True)
  if not pcap:
      print "Error loading C libary: %s" % errno.errorcode[ctypes.get_errno()]
  print "* C runtime libary loaded: %s" % OSX_PCAP_DYLIB
  print "* C runtime handle at: %s" % pcap
  
  print "-------------------------------------------"
  pcap_lookupdev = pcap.pcap_lookupdev
  pcap_lookupdev.restype = ctypes.c_char_p
  dev = pcap.pcap_lookupdev()
  print "* Device handle at: %s" % dev
  
  net = ctypes.c_uint()
  mask = ctypes.c_uint()
  pcap.pcap_lookupnet(dev,ctypes.byref(net),ctypes.byref(mask),err_buf)
  print "* Device IP to bind: %s" % net
  print "* Device net mask: %s" % mask
  
  #pcap_t *pcap_open_live(const char *device, int snaplen,int promisc, int to_ms, char *errbuf)
  pcap_open_live = pcap.pcap_open_live
  pcap_open_live.restype = ctypes.POINTER(ctypes.c_void_p)
  pcap_create = pcap.pcap_create
  pcap_create.restype = ctypes.c_void_p
  #pcap_handle = pcap.pcap_create(dev, err_buf)
  pcap_handle = pcap.pcap_open_live(dev, 1024, packet_count_limit, timeout_limit, err_buf)
  print "* Live capture device handle at: %s" % pcap_handle 
  
  pcap_can_set_rfmon = pcap.pcap_can_set_rfmon
  pcap_can_set_rfmon.argtypes = [ctypes.c_void_p]
  if (pcap_can_set_rfmon(pcap_handle) == 1):
      print "* Can set interface in monitor mode"
  
  pcap_pkthdr_p = ctypes.POINTER(pcap_pkthdr)()
  packetdata = ctypes.POINTER(ctypes.c_ubyte*65536)()
  #print pcap.pcap_next(pcap_handle,ctypes.byref(pcap_pkthdr_p))
  
  if (pcap.pcap_next_ex(pcap_handle, ctypes.byref(pcap_pkthdr_p), ctypes.byref(packetdata)) == 1):
      print "* Packet captured!"
      pkthandler(pcap_pkthdr_p,packetdata)
  
subject: Create osx-libpcap-test.py