trafgen: Allow to generate packets to output pcap file
Add trafgen_dev.c module which provides generic way of
reading and writing packets to/from networking device or a pcap file.
Also allow to handle output pcap file via '-o, --out, --dev' option.
It might be useful in future for testing some link protocols which is
not easy to capture (e.g. wlan packets) w/o having some special setup.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
[tklauser: fix whitespace issues]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>