listen.c, bpf.c, bpf.h:
  On the BSD's the actual writing of packets captured by bpf to a file
  is done in the kernel; see our bpf modifications in sys/net.  However,
  listen.c oversees this process, initializing the bpf interface,
  monitoring the file as it is created and moving it when it gets too
  large, etc. The low-level routines that manage the bpf interface,
  including opening it, associating a network interface with it, giving
  it a file to write packets to, etc., are in bpf.c.

lin_listen.c, lin_packet.c, lin_packet.h, segnames.c, segnames.h:
  This is the code for the linux version of listen. lin_packet.c
  contains the low-level code that opens the interface, reads packets
  from it, and keeps statistics.  segnames.c contains code that
  generates the names of segment files.

listen.sh:
  wrapper for listen, to capture output and return value in a log file.
