From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7FFACC433E0 for ; Fri, 12 Jun 2020 22:13:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A03D20663 for ; Fri, 12 Jun 2020 22:13:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Re2zPzqZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726307AbgFLWN2 (ORCPT ); Fri, 12 Jun 2020 18:13:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726268AbgFLWN2 (ORCPT ); Fri, 12 Jun 2020 18:13:28 -0400 Received: from mail-lj1-x241.google.com (mail-lj1-x241.google.com [IPv6:2a00:1450:4864:20::241]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1891DC03E96F; Fri, 12 Jun 2020 15:13:27 -0700 (PDT) Received: by mail-lj1-x241.google.com with SMTP id i27so12747171ljb.12; Fri, 12 Jun 2020 15:13:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=2iDyXafqhLsVrluQiOl3buIl3fneuyWH/g+kH0A8cpg=; b=Re2zPzqZ0NC9n29JrL34B6vTkNv3x+UjFVfDX1ep8IaUIqUteHjVmX1GqtfyXPAjDG rTZc30M8pW9LpaVpwoUK9z9Icphvb3iQNTMCUtV/aQAySYs4SEp2fKaenN0l3DGAg9K5 ft5raUj+mzh62iWewNTVQmM/wRmG/N9jSOaIPz8ajUtTHWzxZlAQISQrE9FZCTs4LCgJ asN/yU8P2EX1j6uOAYSd2eyzEARO5KGlCnzR+IwaQSfecUnErYWEnx13FmzoxHuR6Ijv LL9naANrOJ+86Npz4tUr0RLByedFhX+fyNWMFuZK8pn6jmYAa3am4+FjIipWzPDq9Kzb sgkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=2iDyXafqhLsVrluQiOl3buIl3fneuyWH/g+kH0A8cpg=; b=iqL4+CTwcFncNbJdi+QGf+s51W3QqfTvDJmeKhLq8gicUARLn8KnPEtw5QXvwVP/ee pLuS9n3nQJV7FWsdzVUfNm8b0WnBOQ78RfFn6wnSMh5Y0qzOecXw9bdVcc5rv3gFOuOv 6DnXXRFINQBZ0iZwa1gTZfzWfhGkzqcJPdDZut6CyhzrPoU//n/n9bP8YZz8prOsABIj oEA5cyhnaCfP7M2Ea98dX0kIfU2CVp1LnSHTMAjWL2sQkuEQ5JAt7PUyxYxPxINVfYya LdPirMGKjc/7ySR5q6alZSpoRiNqzUf4F/05UIg2eqAMx+RYkFl8g9UCVsmEyFhapmPf jfHw== X-Gm-Message-State: AOAM531fTsNd1ho5017iOYLq4o0lMSAUh0olvccMchc2J5QYcXdDflLX p2pQbba720wGlbbpMKp9oQkf55huZ9bB5WSC9Zg= X-Google-Smtp-Source: ABdhPJx9HOcnxrVGiA8RTLC4empHsMB9raNegqTbHMNn9Eyxh7C3RJPlYAvQSEbdOhQd029oKp4gRiiKwUYHk4nYi2c= X-Received: by 2002:a2e:9187:: with SMTP id f7mr8094978ljg.450.1592000005526; Fri, 12 Jun 2020 15:13:25 -0700 (PDT) MIME-Version: 1.0 References: <26038a28c21fea5d04d4bd4744c5686d3f2e5504.1591784177.git.sd@queasysnail.net> <20200612121526.4810a073@toad> In-Reply-To: <20200612121526.4810a073@toad> From: Alexei Starovoitov Date: Fri, 12 Jun 2020 15:13:14 -0700 Message-ID: Subject: Re: [PATCH bpf] bpf: tcp: recv() should return 0 when the peer socket is closed To: Jakub Sitnicki Cc: Sabrina Dubroca , Network Development , John Fastabend , Daniel Borkmann , bpf Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Jun 12, 2020 at 3:18 AM Jakub Sitnicki wrote: > > On Wed, 10 Jun 2020 12:19:43 +0200 > Sabrina Dubroca wrote: > > > If the peer is closed, we will never get more data, so > > tcp_bpf_wait_data will get stuck forever. In case we passed > > MSG_DONTWAIT to recv(), we get EAGAIN but we should actually get > > 0. > > > > From man 2 recv: > > > > RETURN VALUE > > > > When a stream socket peer has performed an orderly shutdown, the > > return value will be 0 (the traditional "end-of-file" return). > > > > This patch makes tcp_bpf_wait_data always return 1 when the peer > > socket has been shutdown. Either we have data available, and it would > > have returned 1 anyway, or there isn't, in which case we'll call > > tcp_recvmsg which does the right thing in this situation. > > > > Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") > > Signed-off-by: Sabrina Dubroca > > --- > > net/ipv4/tcp_bpf.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c > > index 2b915aafda42..7aa68f4aae6c 100644 > > --- a/net/ipv4/tcp_bpf.c > > +++ b/net/ipv4/tcp_bpf.c > > @@ -245,6 +245,9 @@ static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, > > DEFINE_WAIT_FUNC(wait, woken_wake_function); > > int ret = 0; > > > > + if (sk->sk_shutdown & RCV_SHUTDOWN) > > + return 1; > > + > > if (!timeo) > > return ret; > > > > Acked-by: Jakub Sitnicki Applied. Thanks