From patchwork Thu Aug 20 19:00:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin KaFai Lau X-Patchwork-Id: 262181 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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, USER_AGENT_GIT 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 66BF4C433DF for ; Thu, 20 Aug 2020 19:00:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40E1D2075E for ; Thu, 20 Aug 2020 19:00:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="nScexD/S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726772AbgHTTAZ (ORCPT ); Thu, 20 Aug 2020 15:00:25 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:42994 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726664AbgHTTAY (ORCPT ); Thu, 20 Aug 2020 15:00:24 -0400 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 07KJ0GM1023497 for ; Thu, 20 Aug 2020 12:00:23 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=mnRS1F2/4wDAyRY/Q0BMRrCZ5j5BdoxTmEqDe3JRrM0=; b=nScexD/S54xYFrqdZjO8h2IGTBdgOjnWHyxxo4sC+/TarghjhwwzFjDa5dVhHDaaWD0U KCoQ0VNlCPloXk2zd7yumEKvBoSAjO3bz70Nqy9WN5B+I+uuWiJKhEiSKwtMHHhYOC98 3BM36y4TJBxNXogz00jyeCEy5UrPG1+HtpU= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 3304ny00h9-16 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 20 Aug 2020 12:00:23 -0700 Received: from intmgw004.08.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 20 Aug 2020 12:00:18 -0700 Received: by devbig005.ftw2.facebook.com (Postfix, from userid 6611) id CED842945825; Thu, 20 Aug 2020 12:00:14 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Martin KaFai Lau Smtp-Origin-Hostname: devbig005.ftw2.facebook.com To: CC: Alexei Starovoitov , Daniel Borkmann , Eric Dumazet , , Lawrence Brakmo , Neal Cardwell , , Yuchung Cheng , John Fastabend Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v5 bpf-next 01/12] tcp: Use a struct to represent a saved_syn Date: Thu, 20 Aug 2020 12:00:14 -0700 Message-ID: <20200820190014.2883694-1-kafai@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200820190008.2883500-1-kafai@fb.com> References: <20200820190008.2883500-1-kafai@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-08-20_03:2020-08-19,2020-08-20 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 impostorscore=0 spamscore=0 bulkscore=0 mlxlogscore=754 clxscore=1015 priorityscore=1501 malwarescore=0 lowpriorityscore=0 suspectscore=38 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008200151 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The TCP_SAVE_SYN has both the network header and tcp header. The total length of the saved syn packet is currently stored in the first 4 bytes (u32) of an array and the actual packet data is stored after that. A later patch will add a bpf helper that allows to get the tcp header alone from the saved syn without the network header. It will be more convenient to have a direct offset to a specific header instead of re-parsing it. This requires to separately store the network hdrlen. The total header length (i.e. network + tcp) is still needed for the current usage in getsockopt. Although this total length can be obtained by looking into the tcphdr and then get the (th->doff << 2), this patch chooses to directly store the tcp hdrlen in the second four bytes of this newly created "struct saved_syn". By using a new struct, it can give a readable name to each individual header length. Acked-by: John Fastabend Reviewed-by: Eric Dumazet Signed-off-by: Martin KaFai Lau --- include/linux/tcp.h | 7 ++++++- include/net/request_sock.h | 8 +++++++- net/core/filter.c | 4 ++-- net/ipv4/tcp.c | 9 +++++---- net/ipv4/tcp_input.c | 16 +++++++++------- 5 files changed, 29 insertions(+), 15 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 14b62d7df942..2088d5a079af 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -406,7 +406,7 @@ struct tcp_sock { * socket. Used to retransmit SYNACKs etc. */ struct request_sock __rcu *fastopen_rsk; - u32 *saved_syn; + struct saved_syn *saved_syn; }; enum tsq_enum { @@ -484,6 +484,11 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp) tp->saved_syn = NULL; } +static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn) +{ + return saved_syn->network_hdrlen + saved_syn->tcp_hdrlen; +} + struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, const struct sk_buff *orig_skb); diff --git a/include/net/request_sock.h b/include/net/request_sock.h index b2eb8b4ba697..7d9ed99a77bd 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -41,6 +41,12 @@ struct request_sock_ops { int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req); +struct saved_syn { + u32 network_hdrlen; + u32 tcp_hdrlen; + u8 data[]; +}; + /* struct request_sock - mini sock to represent a connection request */ struct request_sock { @@ -60,7 +66,7 @@ struct request_sock { struct timer_list rsk_timer; const struct request_sock_ops *rsk_ops; struct sock *sk; - u32 *saved_syn; + struct saved_syn *saved_syn; u32 secid; u32 peer_secid; }; diff --git a/net/core/filter.c b/net/core/filter.c index b2df52086445..c847b1285acd 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4550,9 +4550,9 @@ static int _bpf_getsockopt(struct sock *sk, int level, int optname, tp = tcp_sk(sk); if (optlen <= 0 || !tp->saved_syn || - optlen > tp->saved_syn[0]) + optlen > tcp_saved_syn_len(tp->saved_syn)) goto err_clear; - memcpy(optval, tp->saved_syn + 1, optlen); + memcpy(optval, tp->saved_syn->data, optlen); break; default: goto err_clear; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 31f3b858db81..87d3036d8bd8 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3788,20 +3788,21 @@ static int do_tcp_getsockopt(struct sock *sk, int level, lock_sock(sk); if (tp->saved_syn) { - if (len < tp->saved_syn[0]) { - if (put_user(tp->saved_syn[0], optlen)) { + if (len < tcp_saved_syn_len(tp->saved_syn)) { + if (put_user(tcp_saved_syn_len(tp->saved_syn), + optlen)) { release_sock(sk); return -EFAULT; } release_sock(sk); return -EINVAL; } - len = tp->saved_syn[0]; + len = tcp_saved_syn_len(tp->saved_syn); if (put_user(len, optlen)) { release_sock(sk); return -EFAULT; } - if (copy_to_user(optval, tp->saved_syn + 1, len)) { + if (copy_to_user(optval, tp->saved_syn->data, len)) { release_sock(sk); return -EFAULT; } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 184ea556f50e..4aaedcf71973 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6599,13 +6599,15 @@ static void tcp_reqsk_record_syn(const struct sock *sk, { if (tcp_sk(sk)->save_syn) { u32 len = skb_network_header_len(skb) + tcp_hdrlen(skb); - u32 *copy; - - copy = kmalloc(len + sizeof(u32), GFP_ATOMIC); - if (copy) { - copy[0] = len; - memcpy(©[1], skb_network_header(skb), len); - req->saved_syn = copy; + struct saved_syn *saved_syn; + + saved_syn = kmalloc(struct_size(saved_syn, data, len), + GFP_ATOMIC); + if (saved_syn) { + saved_syn->network_hdrlen = skb_network_header_len(skb); + saved_syn->tcp_hdrlen = tcp_hdrlen(skb); + memcpy(saved_syn->data, skb_network_header(skb), len); + req->saved_syn = saved_syn; } } }