From owner-freebsd-hackers Mon Jan 17 9:28:53 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from whizzo.transsys.com (whizzo.TransSys.COM [144.202.42.10]) by hub.freebsd.org (Postfix) with ESMTP id E06AD14D5E for ; Mon, 17 Jan 2000 09:28:49 -0800 (PST) (envelope-from louie@whizzo.transsys.com) Received: from whizzo.transsys.com (localhost.transsys.com [127.0.0.1]) by whizzo.transsys.com (8.9.3/8.9.1) with ESMTP id MAA19299; Mon, 17 Jan 2000 12:28:42 -0500 (EST) (envelope-from louie@whizzo.transsys.com) Message-Id: <200001171728.MAA19299@whizzo.transsys.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: Charles Youse Cc: freebsd-hackers@FreeBSD.ORG From: "Louis A. Mamakos" Subject: Re: PR kern/15656 References: In-reply-to: Your message of "Mon, 17 Jan 2000 11:55:37 EST." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 17 Jan 2000 12:28:42 -0500 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Agreed; however, the PR states that should the checksum be 0xFFFF, the > complement of which is 0x0000, the checksum should still be sent as > 0xFFFF. Ok, I looked at the PR, which seems to refer to the TCP header checksum, rather than the checksum in the IP header. So please disregard the specific pointer to RFC-791. > Can anyone verify this? I can verify that BSD sends 0-checksums; I can't > on Solaris. For other than the intentional UDP-checksum is zero case (which shouldn't really occur), the stack shouldn't be sending checksums in the protocol headers valued 0x0000. Looking at the in_cksum code, it would appear that a test at the very final step might be necessary (if you presume that the intermediate computations might produce a -0). But that code is highly tuned, and more than a cursory examination is called for. louie To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message