From owner-freebsd-current Thu Dec 23 11:27:35 1999 Delivered-To: freebsd-current@freebsd.org Received: from skynet.ctr.columbia.edu (skynet.ctr.columbia.edu [128.59.64.70]) by hub.freebsd.org (Postfix) with SMTP id 5A9AF15032 for ; Thu, 23 Dec 1999 11:27:31 -0800 (PST) (envelope-from wpaul@skynet.ctr.columbia.edu) Received: (from wpaul@localhost) by skynet.ctr.columbia.edu (8.6.12/8.6.9) id OAA11526; Thu, 23 Dec 1999 14:30:48 -0500 From: Bill Paul Message-Id: <199912231930.OAA11526@skynet.ctr.columbia.edu> Subject: Re: Woa! May have found something - 'rl' driver and small packets (was Re: Odd TCP glitches in new currents) To: dillon@apollo.backplane.com (Matthew Dillon) Date: Thu, 23 Dec 1999 14:30:47 -0500 (EST) 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 In-Reply-To: <199912230641.WAA16876@apollo.backplane.com> from "Matthew Dillon" at Dec 22, 99 10:41:13 pm X-Mailer: ELM [version 2.4 PL24] Content-Type: text Content-Length: 1183 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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 Work: wpaul@ctr.columbia.edu | Center for Telecommunications Research Home: wpaul@skynet.ctr.columbia.edu | Columbia University, New York City ============================================================================= "It is not I who am crazy; it is I who am mad!" - Ren Hoek, "Space Madness" ============================================================================= To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message