From patchwork Mon Oct 17 21:34:47 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerrit Renker X-Patchwork-Id: 120302 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 22A28B70B2 for ; Tue, 18 Oct 2011 08:35:11 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754242Ab1JQVfE (ORCPT ); Mon, 17 Oct 2011 17:35:04 -0400 Received: from dee.erg.abdn.ac.uk ([139.133.204.82]:36621 "EHLO erg.abdn.ac.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754147Ab1JQVfD (ORCPT ); Mon, 17 Oct 2011 17:35:03 -0400 Received: from laptev.erg.abdn.ac.uk (Debian-exim@ra-gerrit.erg.abdn.ac.uk [139.133.204.38]) by erg.abdn.ac.uk (8.13.4/8.13.4) with ESMTP id p9HLYmEN001469 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT); Mon, 17 Oct 2011 22:34:49 +0100 (BST) Received: from gerrit by laptev.erg.abdn.ac.uk with local (Exim 4.72) (envelope-from ) id 1RFupb-000146-Q5; Mon, 17 Oct 2011 15:34:47 -0600 Date: Mon, 17 Oct 2011 15:34:47 -0600 From: Gerrit Renker To: "David S. Miller" , netdev@vger.kernel.org Subject: net [BUG-FIX][PATCH 1/1] udplite: fast-path computation of checksum coverage Message-ID: <20111017213447.GA4061@gerrit.erg.abdn.ac.uk> Mail-Followup-To: Gerrit Renker , "David S. Miller" , netdev@vger.kernel.org MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) X-ERG-MailScanner: Found to be clean X-ERG-MailScanner-From: gerrit@erg.abdn.ac.uk X-Spam-Status: No Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Dave, can you please consider the fix below -- the checksum coverage in UDP-Lite had been broken for over half a year; then reported by Thomas. I have tested the patch below in various scenarios with IPv4 and IPv6, on localhost, and between multiple hosts. Gerrit >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Patch <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< udplite: fast-path computation of checksum coverage Commit 903ab86d195cca295379699299c5fc10beba31c7 of 1 March this year ("udp: Add lockless transmit path") introduced a new fast TX path that broke the checksum coverage computation of UDP-lite, which so far depended on up->len (only set if the socket is locked and 0 in the fast path). Fixed by providing both fast- and slow-path computation of checksum coverage. The latter can be removed when UDP(-lite)v6 also uses a lockless transmit path. Reported-by: Thomas Volkert Signed-off-by: Gerrit Renker --- include/net/udplite.h | 63 ++++++++++++++++++++++++-------------------------- 1 file changed, 31 insertions(+), 32 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/include/net/udplite.h +++ b/include/net/udplite.h @@ -66,40 +66,34 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) return 0; } -static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh) +/* Slow-path computation of checksum. Socket is locked. */ +static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) { + const struct udp_sock *up = udp_sk(skb->sk); int cscov = up->len; + __wsum csum = 0; - /* - * Sender has set `partial coverage' option on UDP-Lite socket - */ - if (up->pcflag & UDPLITE_SEND_CC) { + if (up->pcflag & UDPLITE_SEND_CC) { + /* + * Sender has set `partial coverage' option on UDP-Lite socket. + * The special case "up->pcslen == 0" signifies full coverage. + */ if (up->pcslen < up->len) { - /* up->pcslen == 0 means that full coverage is required, - * partial coverage only if 0 < up->pcslen < up->len */ - if (0 < up->pcslen) { - cscov = up->pcslen; - } - uh->len = htons(up->pcslen); + if (0 < up->pcslen) + cscov = up->pcslen; + udp_hdr(skb)->len = htons(up->pcslen); } - /* - * NOTE: Causes for the error case `up->pcslen > up->len': - * (i) Application error (will not be penalized). - * (ii) Payload too big for send buffer: data is split - * into several packets, each with its own header. - * In this case (e.g. last segment), coverage may - * exceed packet length. - * Since packets with coverage length > packet length are - * illegal, we fall back to the defaults here. - */ + /* + * NOTE: Causes for the error case `up->pcslen > up->len': + * (i) Application error (will not be penalized). + * (ii) Payload too big for send buffer: data is split + * into several packets, each with its own header. + * In this case (e.g. last segment), coverage may + * exceed packet length. + * Since packets with coverage length > packet length are + * illegal, we fall back to the defaults here. + */ } - return cscov; -} - -static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) -{ - int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb)); - __wsum csum = 0; skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ @@ -115,16 +109,21 @@ static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) return csum; } +/* Fast-path computation of checksum. Socket may not be locked. */ static inline __wsum udplite_csum(struct sk_buff *skb) { - struct sock *sk = skb->sk; - int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb)); + const struct udp_sock *up = udp_sk(skb->sk); const int off = skb_transport_offset(skb); - const int len = skb->len - off; + int len = skb->len - off; + if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { + if (0 < up->pcslen) + len = up->pcslen; + udp_hdr(skb)->len = htons(up->pcslen); + } skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ - return skb_checksum(skb, off, min(cscov, len), 0); + return skb_checksum(skb, off, len, 0); } extern void udplite4_register(void);