From patchwork Mon Nov 9 21:15:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Lobakin X-Patchwork-Id: 322027 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED01EC56201 for ; Mon, 9 Nov 2020 21:15:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A894206ED for ; Mon, 9 Nov 2020 21:15:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=pm.me header.i=@pm.me header.b="h62fmhbf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730490AbgKIVPe (ORCPT ); Mon, 9 Nov 2020 16:15:34 -0500 Received: from mail-03.mail-europe.com ([91.134.188.129]:46506 "EHLO mail-03.mail-europe.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729697AbgKIVPd (ORCPT ); Mon, 9 Nov 2020 16:15:33 -0500 Date: Mon, 09 Nov 2020 21:15:19 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail; t=1604956528; bh=zTOBwWAH6JdA/Q03nXi6Nv+Ot9+RM1svymVRReyFZ/8=; h=Date:To:From:Cc:Reply-To:Subject:From; b=h62fmhbfhOQh29yjgA3Xy2EV/wnNK+6x2cCmxLhCpZOYToq+Wxq/DKNc4C3L7qly+ fhI8MT7TLwEmLfVel4vhk+bByJHsNON9hYijHc0KcPPqXATGQSLf9YoRmliXcx9YRR oivPpGExOwk4+cP7XL0CqUsb79xq3JJWVNPjSh1QfpUw3VYwjGs1xHCq+yzm29xXUp oYbgnAQfcN6pBO1CWZepGdKrAQLQXTBlhGAkzpNr315v/KjAOdyQHoNE2kUQ+wE2pw ADlyQrF79KqzyPbtnlc7pwp+RjhGVit/JxSOSux+tEWPbD2z7QxbtkmP+kd/l6SJcw Q2JPLlNI3x9og== To: "David S. Miller" , Jakub Kicinski From: Alexander Lobakin Cc: Alexey Kuznetsov , Hideaki YOSHIFUJI , Paolo Abeni , Willem de Bruijn , Steffen Klassert , Alexander Lobakin , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Reply-To: Alexander Lobakin Subject: [PATCH v3 net] net: udp: fix Fast/frag0 UDP GRO Message-ID: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org While testing UDP GSO fraglists forwarding through driver that uses Fast GRO (via napi_gro_frags()), I was observing lots of out-of-order iperf packets: [ ID] Interval Transfer Bitrate Jitter [SUM] 0.0-40.0 sec 12106 datagrams received out-of-order Simple switch to napi_gro_receive() any other method without frag0 shortcut completely resolved them. I've found that UDP GRO uses udp_hdr(skb) in its .gro_receive() callback. While it's probably OK for non-frag0 paths (when all headers or even the entire frame are already in skb->data), this inline points to junk when using Fast GRO (napi_gro_frags() or napi_gro_receive() with only Ethernet header in skb->data and all the rest in shinfo->frags) and breaks GRO packet compilation and the packet flow itself. To support both modes, skb_gro_header_fast() + skb_gro_header_slow() are typically used. UDP even has an inline helper that makes use of them, udp_gro_udphdr(). Use that instead of troublemaking udp_hdr() to get rid of the out-of-order delivers. Present since the introduction of plain UDP GRO in 5.0-rc1. Since v2 [1]: - dropped redundant check introduced in v2 as it's performed right before (thanks to Eric); - udp_hdr() switched to data + off for skbs from list (also Eric); - fixed possible malfunction of {,__}udp{4,6}_lib_lookup_skb() with Fast/frag0 due to ip{,v6}_hdr() usage (Willem). Since v1 [2]: - added a NULL pointer check for "uh" as suggested by Willem. [1] https://lore.kernel.org/netdev/0eaG8xtbtKY1dEKCTKUBubGiC9QawGgB3tVZtNqVdY@cp4-web-030.plabs.ch [2] https://lore.kernel.org/netdev/YazU6GEzBdpyZMDMwJirxDX7B4sualpDG68ADZYvJI@cp4-web-034.plabs.ch Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.") Signed-off-by: Alexander Lobakin --- net/ipv4/udp.c | 4 ++-- net/ipv4/udp_offload.c | 9 ++++++--- net/ipv6/udp.c | 4 ++-- 3 files changed, 10 insertions(+), 7 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 09f0a23d1a01..948ddc9a0212 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -534,7 +534,7 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport, struct udp_table *udptable) { - const struct iphdr *iph = ip_hdr(skb); + const struct iphdr *iph = skb_gro_network_header(skb); return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport, iph->daddr, dport, inet_iif(skb), @@ -544,7 +544,7 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb, struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport) { - const struct iphdr *iph = ip_hdr(skb); + const struct iphdr *iph = skb_gro_network_header(skb); return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport, iph->daddr, dport, inet_iif(skb), diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index e67a66fbf27b..dbc4d17c55e9 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -366,11 +366,11 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, static struct sk_buff *udp_gro_receive_segment(struct list_head *head, struct sk_buff *skb) { - struct udphdr *uh = udp_hdr(skb); + struct udphdr *uh = udp_gro_udphdr(skb); struct sk_buff *pp = NULL; struct udphdr *uh2; struct sk_buff *p; - unsigned int ulen; + u32 ulen, off; int ret = 0; /* requires non zero csum, for symmetry with GSO */ @@ -385,6 +385,9 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head, NAPI_GRO_CB(skb)->flush = 1; return NULL; } + + off = skb_gro_offset(skb); + /* pull encapsulating udp header */ skb_gro_pull(skb, sizeof(struct udphdr)); @@ -392,7 +395,7 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head, if (!NAPI_GRO_CB(p)->same_flow) continue; - uh2 = udp_hdr(p); + uh2 = (void *)p->data + off; /* Match ports only, as csum is always non zero */ if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 29d9691359b9..a256ecce76b2 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -269,7 +269,7 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport, struct udp_table *udptable) { - const struct ipv6hdr *iph = ipv6_hdr(skb); + const struct ipv6hdr *iph = skb_gro_network_header(skb); return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport, &iph->daddr, dport, inet6_iif(skb), @@ -279,7 +279,7 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb, struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport) { - const struct ipv6hdr *iph = ipv6_hdr(skb); + const struct ipv6hdr *iph = skb_gro_network_header(skb); return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport, &iph->daddr, dport, inet6_iif(skb),