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Date:      Thu, 23 Dec 1999 12:32:34 -0800 (PST)
From:      Matthew Dillon <dillon@apollo.backplane.com>
To:        Bill Paul <wpaul@skynet.ctr.columbia.edu>
Cc:        julian@whistle.com, scottm@CS.UCLA.EDU, jlemon@americantv.com, brad@shub-internet.org, jabley@patho.gen.nz, phk@critter.freebsd.dk, wollman@khavrinen.lcs.mit.edu, current@freebsd.org
Subject:   Re: Woa!  May have found something - 'rl' driver and small packets (was Re: Odd TCP glitches in new currents)
Message-ID:  <199912232032.MAA07521@apollo.backplane.com>
References:   <199912231930.OAA11526@skynet.ctr.columbia.edu>

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:Okay, I patched if_rl.c in -current to fixe the problem demonstrated by 
:Matt's linktest program. The bug was actually on the receive side of the 
:rl driver, not the transmit side. A packet can wrap from the end of the 
:RX buffer back to the beginning, and in some cases these packets would 
:get lost due to botched use of m_pullup(). I can run the linktest 
:program now without losing any frames.
:
:There's another way around this which is to allocate a whole mbuf
:cluster when you know the packet is wrapped and bcopy the data manually
:instead of using m_devget(), but I'm not sure I want to waste a whole
:cluster just for that case.
:
:-Bill
:
:-- 
:=============================================================================
:-Bill Paul            (212) 854-6020 | System Manager, Master of Unix-Fu

    Great!  Thanks for your help, Bill!

						-Matt



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