Re: Wireshark may get ISN wrong

[ronnie sahlberg <ronniesahlberg () gmail com>]

You can just disable relative sequence numbers in the preferences for tcp.


On Mon, Nov 17, 2014 at 9:38 AM, Matt <mattator () gmail com> wrote:
> Hi,
>
> I use wireshark to examinate some traces generated by a network
> simulator (ns3 www.nsnam.org) which set the ISN to 0 (no randomization
> yet).
> As wireshark assumes base_seq == 0 to be an unitialized value, it
> triggers some error as wireshark tries to set again and again the base
> seq. Here is the output of a single 3WHS (custom printf), in peculiar
> in the 4th line, which is the ACK of the 3WHS, wiresharks sets
> base_seq =seq-1, ie 0-1 and it wraps the seq number (ugly).
>
> Setting base seq to : 0
> Setting base seq to : 0
> Setting rev base seq to : 0
> Setting base seq to : 4294967295
> Setting rev base seq to : 0
> Setting rev base seq to : 0
> Setting base seq to : 0
> Setting base seq to : 0
> Setting rev base seq to : 0
> Setting base seq to : 0
> Setting rev base seq to : 0
> Setting base seq to : 1
>
> I understand it seems a corner case but I don't believe have an ISN
> equal to 0 is forbidden by the RFC ?!
> I was wondering if I could add some boolean such as "base_seq_set" in
> mptcp_info_t to prevent such a behavior.
>
> Regards
> Matt
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