Re: RFC1323. No timestamping if SYN timestamp = 0. Bug or Feature?

[Casey Carter <Casey@xxxxxxxxxx>]

David S. Miller wrote:

> It is impossible to comply to RFC1323 if we allow TSval in the
> initial SYN packet to be zero, from RFC1323:
>
>         When TSecr is not valid, its value must be zero.
>
> It is therefore impossible to accept TSval as zero, because
> our TSecr echo of that timestamp would be also zero and thus
> invalid.
>
> That is why we reject zero timestamps in the initial SYN packet.
>  
Note that the text does not say "When TSecr is zero, it is invalid."  
You are reversing the conditional statement "not valid implies zero" to 
"zero implies not valid." I don't think that the intent of this text in 
the RFC is to forbid the use of zero as a timestamp, but only to assert 
that the value should be set to zero by default.

--
Casey Carter
Casey@xxxxxxxxxx
ccarter@xxxxxxxxxxx
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