[e2e] Data + FIN

[Bob Braden]

  *> the original.  I did a quick perusal of a few RFCs (but definitely not all of
  *> the relevant RFCs) and didn't find anything which makes me think it is
  *> illegal.  Illegal or not, since it is happening in the real world, we need to
  *> handle it.)

It was certainly the intent that it be legal.  Indeed, piggybacking
FINs on the last data packet was worth a bonus point in the
"Pillsburys" (avoiding the forbidden b-word) during initial TCP
imkplementation phase in the late 1970s.

I interpret the last paragraph of page 26 of RFC 793 as saying it IS
legal.  The seq space occupied by the FIN is defined as part of the
SEG.LEN, so it will generally fit into the window.  The detailed rules
beginning on p. 65 clearly are meant to handle FIN bits on the last
data segment.

Bob Braden


  *> 
  *> 
  *> John
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