Wireshark mailing list archives

Re: dissect_ip() and check for header length

From: Guy Harris <guy () alum mit edu>
Date: Thu, 9 Sep 2010 18:31:54 -0700


On Sep 8, 2010, at 8:47 AM, Petr Sumbera wrote:

But the problem is that stored packets for *outgoing* traffic doesn't 
contain "Header length" (it's zero as at layer where it was captured it 
wasn't filled,


...which means, of course, that no outgoing IPv4 traffic *ever* has IP options.

Otherwise, outgoing IPv4 packets would be undissectable unless the IPv4 header length is available elsewhere; you 
cannot dissect an IPv4 header unless you know how big it is, as it's not fixed-length (it's a fixed-length 20-byte 
portion followed by 0 or more bytes of options).
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Current thread:

dissect_ip() and check for header length Petr Sumbera (Sep 09)
- Re: dissect_ip() and check for header length Guy Harris (Sep 09)
- <Possible follow-ups>
- dissect_ip() and check for header length Petr Sumbera (Sep 16)
  - Re: dissect_ip() and check for header length Petr Sumbera (Sep 16)
    - Re: dissect_ip() and check for header length Guy Harris (Sep 16)
    - Re: dissect_ip() and check for header length Petr Sumbera (Sep 17)