From patchwork Sat May 22 19:14:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cong Wang X-Patchwork-Id: 12274659 X-Patchwork-Delegate: bpf@iogearbox.net 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 992C7C4707E for ; Sat, 22 May 2021 19:14:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D92B611AD for ; Sat, 22 May 2021 19:14:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231361AbhEVTPy (ORCPT ); Sat, 22 May 2021 15:15:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231316AbhEVTPy (ORCPT ); Sat, 22 May 2021 15:15:54 -0400 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E719DC06174A; Sat, 22 May 2021 12:14:27 -0700 (PDT) Received: by mail-pj1-x102c.google.com with SMTP id b9-20020a17090a9909b029015cf9effaeaso9045809pjp.5; Sat, 22 May 2021 12:14:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=utSDi74JoxgeFkn6+VzF9KRMzUGip+skVUxRXuPWjX0=; b=O3Jb4RA9S0GMCsd4shWuiFkOxy9/nxrhDF27HPPnJ+uhndrD9sCZq9nvcDVnWy9OlF PvSblcJrheeTGOi2T2tSlmsLvlDLzYlyZrY6Jq4ogkCYLehrbVHdVPY/Jnr+LZKbjfdu RQNEzPg3DpPIPoSmB9DmbWUxvou8DqIivH0yN5biEPgb17f0j8PXXwY1p8uiPOQkcDle dly3nMKnligCnzktPvrcg/UcPuHswuO1kIJWHwvldWIYT/vbJlfwNP2aQMl/vVV9q2xf eXXeiDNSsOHlXT4a7ekpqKSfHOZbKNV7zok2RB8gzcda71sPXc1ll71bclx1Iqjakrcx 9hXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=utSDi74JoxgeFkn6+VzF9KRMzUGip+skVUxRXuPWjX0=; b=NbT1L7Ot5kPmi6Ftwss8vbR933fkqtgMypG1OuvlFHTBxbOR/RNnH+g+5FYfahiB1I 2JFBR5gYGQh007GzwgBFcrnwUYRrrUodvGo0flRG289wVRn54E2OA9XC31h8Yl2jl1nx eeWpVOUilWA8beqUO/1O0q5zjQHZWUVHVPTnDbncyn3PO0ngbesw3DqesIArY/1FjZWr jt9PXj/7DM6l9l3+X8ZFbzmU6EiJonD98Mghp+Ds9uYl/xB9DX9GZJIzAoU1FLhyIsE2 JPqMSMekg8hz9y6k4HGmqRwXsRGBmMrieIuxcsx2dB6seZ9gJhjZEwhhc0modb5sUAEc IvCg== X-Gm-Message-State: AOAM530pfN0tMBe3PkPOVqbTBq3+nCSln/zN0JTIghHL9i8GhLl7WDcn EJAZXirHIl0bAYTco4ENjqknVlF3931fxQ== X-Google-Smtp-Source: ABdhPJzOEq+IGq4SaVUSWZyo+VF/FOKwBPkfnUWcIV22wqZeLeMlvNzY0x4Dg2d5DZyUcHFFX1mlzA== X-Received: by 2002:a17:90a:94ca:: with SMTP id j10mr16638908pjw.59.1621710867325; Sat, 22 May 2021 12:14:27 -0700 (PDT) Received: from unknown.attlocal.net ([2600:1700:65a0:ab60:14cd:343f:4e27:51d7]) by smtp.gmail.com with ESMTPSA id 5sm6677531pfe.32.2021.05.22.12.14.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 May 2021 12:14:27 -0700 (PDT) From: Cong Wang To: netdev@vger.kernel.org Cc: bpf@vger.kernel.org, Cong Wang , John Fastabend , Daniel Borkmann , Jakub Sitnicki , Lorenz Bauer Subject: [Patch bpf v2 1/7] skmsg: improve udp_bpf_recvmsg() accuracy Date: Sat, 22 May 2021 12:14:05 -0700 Message-Id: <20210522191411.21446-2-xiyou.wangcong@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210522191411.21446-1-xiyou.wangcong@gmail.com> References: <20210522191411.21446-1-xiyou.wangcong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Cong Wang I tried to reuse sk_msg_wait_data() for different protocols, but it turns out it can not be simply reused. For example, UDP actually uses two queues to receive skb: udp_sk(sk)->reader_queue and sk->sk_receive_queue. So we have to check both of them to know whether we have received any packet. Also, UDP does not lock the sock during BH Rx path, it makes no sense for its ->recvmsg() to lock the sock. It is always possible for ->recvmsg() to be called before packets actually arrive in the receive queue, we just use best effort to make it accurate here. Fixes: 1f5be6b3b063 ("udp: Implement udp_bpf_recvmsg() for sockmap") Cc: John Fastabend Cc: Daniel Borkmann Cc: Jakub Sitnicki Cc: Lorenz Bauer Signed-off-by: Cong Wang --- include/linux/skmsg.h | 2 -- net/core/skmsg.c | 23 --------------------- net/ipv4/tcp_bpf.c | 24 +++++++++++++++++++++- net/ipv4/udp_bpf.c | 47 ++++++++++++++++++++++++++++++++++++++----- 4 files changed, 65 insertions(+), 31 deletions(-) diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index aba0f0f429be..e3d080c299f6 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -126,8 +126,6 @@ int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, struct sk_msg *msg, u32 bytes); int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, struct sk_msg *msg, u32 bytes); -int sk_msg_wait_data(struct sock *sk, struct sk_psock *psock, int flags, - long timeo, int *err); int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, int len, int flags); diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 43ce17a6a585..f9a81b314e4c 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -399,29 +399,6 @@ int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, } EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter); -int sk_msg_wait_data(struct sock *sk, struct sk_psock *psock, int flags, - long timeo, int *err) -{ - DEFINE_WAIT_FUNC(wait, woken_wake_function); - int ret = 0; - - if (sk->sk_shutdown & RCV_SHUTDOWN) - return 1; - - if (!timeo) - return ret; - - add_wait_queue(sk_sleep(sk), &wait); - sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); - ret = sk_wait_event(sk, &timeo, - !list_empty(&psock->ingress_msg) || - !skb_queue_empty(&sk->sk_receive_queue), &wait); - sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); - remove_wait_queue(sk_sleep(sk), &wait); - return ret; -} -EXPORT_SYMBOL_GPL(sk_msg_wait_data); - /* Receive sk_msg from psock->ingress_msg to @msg. */ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, int len, int flags) diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index ad9d17923fc5..bb49b52d7be8 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -163,6 +163,28 @@ static bool tcp_bpf_stream_read(const struct sock *sk) return !empty; } +static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock, int flags, + long timeo, int *err) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + int ret = 0; + + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + + if (!timeo) + return ret; + + add_wait_queue(sk_sleep(sk), &wait); + sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); + ret = sk_wait_event(sk, &timeo, + !list_empty(&psock->ingress_msg) || + !skb_queue_empty(&sk->sk_receive_queue), &wait); + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); + remove_wait_queue(sk_sleep(sk), &wait); + return ret; +} + static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, int flags, int *addr_len) { @@ -188,7 +210,7 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, long timeo; timeo = sock_rcvtimeo(sk, nonblock); - data = sk_msg_wait_data(sk, psock, flags, timeo, &err); + data = tcp_msg_wait_data(sk, psock, flags, timeo, &err); if (data) { if (!sk_psock_queue_empty(psock)) goto msg_bytes_ready; diff --git a/net/ipv4/udp_bpf.c b/net/ipv4/udp_bpf.c index 954c4591a6fd..565a70040c57 100644 --- a/net/ipv4/udp_bpf.c +++ b/net/ipv4/udp_bpf.c @@ -21,6 +21,45 @@ static int sk_udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, return udp_prot.recvmsg(sk, msg, len, noblock, flags, addr_len); } +static bool udp_sk_has_data(struct sock *sk) +{ + return !skb_queue_empty(&udp_sk(sk)->reader_queue) || + !skb_queue_empty(&sk->sk_receive_queue); +} + +static bool psock_has_data(struct sk_psock *psock) +{ + return !skb_queue_empty(&psock->ingress_skb) || + !sk_psock_queue_empty(psock); +} + +#define udp_msg_has_data(__sk, __psock) \ + ({ udp_sk_has_data(__sk) || psock_has_data(__psock); }) + +static int udp_msg_wait_data(struct sock *sk, struct sk_psock *psock, int flags, + long timeo, int *err) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + int ret = 0; + + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + + if (!timeo) + return ret; + + add_wait_queue(sk_sleep(sk), &wait); + sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); + ret = udp_msg_has_data(sk, psock); + if (!ret) { + wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); + ret = udp_msg_has_data(sk, psock); + } + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); + remove_wait_queue(sk_sleep(sk), &wait); + return ret; +} + static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, int flags, int *addr_len) { @@ -34,8 +73,7 @@ static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, if (unlikely(!psock)) return sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len); - lock_sock(sk); - if (sk_psock_queue_empty(psock)) { + if (!psock_has_data(psock)) { ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len); goto out; } @@ -47,9 +85,9 @@ static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, long timeo; timeo = sock_rcvtimeo(sk, nonblock); - data = sk_msg_wait_data(sk, psock, flags, timeo, &err); + data = udp_msg_wait_data(sk, psock, flags, timeo, &err); if (data) { - if (!sk_psock_queue_empty(psock)) + if (psock_has_data(psock)) goto msg_bytes_ready; ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len); goto out; @@ -62,7 +100,6 @@ static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, } ret = copied; out: - release_sock(sk); sk_psock_put(sk, psock); return ret; }