====== read packets ======

<code python>rdpcap(filename, count=-1 )</code>
reads a pcap file and returns the list of read packets. If count is positive, only the first count packets are read.
 <code python>rdpcap("ike.cap")
<ike.cap: UDP:45 TCP:0 ICMP:0 Other:0>
rdpcap("ike.cap", count=10)
<ike.cap: UDP:10 TCP:0 ICMP:0 Other:0></code>

====== write packets ======

<code python>wrpcap(filename, pkt, linktype=None)</code>
Write a packet or list of packets to a pcap file. linktype can be used to
force the link type value written into the file.
<code python>wrpcap("my.pcap", packet-list)</code>

====== Quelle ======

  * www.secdev.org/projects/scapy/files/scapydoc.pdf - S. 32
  * https://stackoverflow.com/questions/33740583/writing-to-a-pcap-with-scapy
  * https://stackoverflow.com/questions/7574092/python-scapy-wrpcap-how-do-you-append-packets-to-a-pcap-file