Nosuid TCP/IP ping 1.6
----------------------
(c) 1998, 2003 Michal Zalewski <lcamtuf@coredump.cx> 

Newest version always at:
http://lcamtuf.coredump.cx/soft/poink.zip

--
The Nosuid TCP/IP ping and related utilities are free software; you 
can redistribute it and/or modify it under the terms of the GNU Library
General Public License as published by the Free Software Foundation;
either version 2 of the License, or (at your option) any later version.
--

Not much to say... This is a nosuid, so quite secure, version of ping utility
for IPv4. It uses dirty trick - TCP linear SYN/RST challenge instead of 
ICMP echo/echo reply. It won't allow any flood-pings (others than connect
flood you could achieve anyway), security compromises etc.

Currently, basic ping parameters are implemented (compatible with
original ping):

ping [ -i delay ] [ -c count ] [ -t timeout ] hostname

  -i delay	- delay between pings in seconds (default 1, min. 1)
  -c count	- number of packets to send (default: 0 - until break)
  -t timeout	- packet timeout in seconds (default: 4, min. 1)
 
                  NOTE: longer timeouts might result in slightly inaccurate
                  results because of TCP/IP retransmits.
 
When finished or stopped with Ctrl+C (SIGINT), poink prints some statistics 
about round-trip times, jest like the original ping does. Round-trip times 
are displayed in miliseconds (1/1000 of second, ms), but unlike its setuid
counterpart, nosuid ping additionally displays time in microseconds 
(1/1000000 of second, usec) if trip time is really low (well, I think that
more recent versions of ping are doing it now, too).

Currently, Linux is the only supported platform, but BSD port should
be really easy to develop.

Aah, if during pinging you'll see '(skew!)' at the end of line, ping
result is (slightly) unrealible. It means that the port used for the
connection turned out to be open, and the RTT time is for a full TCP
handshake, not reset. If skew has been detected, poink tries to fix it 
while sending next packet, and you shouldn't see that message too often.

-- Aug 08 1998
