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Bug in ping? ICMP Sequence Number octets are reversed
- From: Gary Johnson <garyjohn at spk dot agilent dot com>
- To: cygwin at cygwin dot com
- Date: Thu, 12 Jun 2008 22:39:09 -0700
- Subject: Bug in ping? ICMP Sequence Number octets are reversed
I've been using Cygwin's ping (/usr/bin/ping, ping-1.0-1) to do some
testing of IP over a wireless modem. In the process, I was trying
to correlate the icmp_seq values in ping's output with the ICMP
Sequence Number field values in a log of the IP messages. What I
discovered is that the Sequence Number field values increment like
this:
0x0000
0x0100
0x0200
0x0300
...
0xfe00
0xff00
0x0001
0x0101
0x0201
...
It looks like someone just wrote a short integer to the sequence
number field without calling htons() to perform the possible
little-endian to big-endian conversion.
Granted, RFC 792 doesn't specify how this number is to be
incremented, and the current behavior is consistent with Windows'
ping, but this behavior just doesn't seem right. It also makes is
slightly more of a pain to correlate my IP log to ping's display. I
would compare it to ping on other systems, but I don't have a
convenient way to sniff those packets.
Regards,
Gary
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