make: force to overwrite symlink

When doing to successive ``make install'' ln will throw an error
that the symlink already exist, so simply force it to overwrite.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
pcap: let netsniff-ng also record pkt timestamp source

With commit [1] in the kernel, we can also store the timestamp
source in the pcap packet header for later analysis. We do this
by splitting the netsniff-ng's u32 ifindex into u16 tsource and
u16 ifindex. Older kernel do not support the timestamp source in
PF_PACKET, so it will stay 0 and is compatible with older
netsniff-ng binaries.

  [1] http://thread.gmane.org/gmane.linux.network/266878/

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
man: add description about different pcap formats

Add a more detailled description of netsniff-ng's -D option into
the man-page.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
pcap_io: minor: fix some quirks

We can just replace int with uin32_t, that's no problem. Also
fix one case where we moved to uint16_t.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
trafgen: lexer: also allow short forms for hex and binary

Also allow for ...

 - hex:		0xff, xff
 - binary:	0b11110000, b11110000

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
man: trafgen: update documentation for hex, bin forms

Also update examples for the man-page.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
docs: minor: fix mentioning of Documentation/

The Documentation/ folder no longer exists. Either everything important
can be found in the man pages or other documentation files. Fix the
mentioning of Documentation/.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
make: allow to overwrite CFLAGS, CCACHE

Allow to define custom compile flags, e.g. ...

  make CFLAGS="-O2 -Wall"

... and also allow to overwrite ccache variable:

  make CCACHE= all

Also do some minor fixes when built with -O2 -Wall.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>