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 76883C433E0 for ; Fri, 12 Jun 2020 22:53:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D7A12078A for ; Fri, 12 Jun 2020 22:53:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NvMCchhC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726417AbgFLWxI (ORCPT ); Fri, 12 Jun 2020 18:53:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726371AbgFLWxH (ORCPT ); Fri, 12 Jun 2020 18:53:07 -0400 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15667C03E96F; Fri, 12 Jun 2020 15:53:07 -0700 (PDT) Received: by mail-pg1-x543.google.com with SMTP id e18so4790411pgn.7; Fri, 12 Jun 2020 15:53:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-transfer-encoding; bh=asGwvdUrTjw8DorufZbYD6ASVjYTNUZUj3WddLs7tLc=; b=NvMCchhChQweyJ/aUDC5d9dd8HfY71ySLHinqAoVnwRXavWngxHk5aGPik8xhVRy3t wzTsxAD/OJ2SOQvOaLg4Go7U7oWrYBSaHWCpy8qxQU1U/SrQApMSWBIMMWEiWBTC+kcs bQsnmyf9+sA/2KRmzOy9zuXwWbRWnJw6m5L2JoSbdblSHeKYYpgAgXErYaL0g8/B5Ehz KAGPQeOAmzs/Smr21NfODwEVZGjnuB0dCU2FH0pY/adp0BMB7buOeAEIKmAbTVx5LrXb DKff9HTjqRRZcmx1YIwjaOV9pFNgq2ohFREwL/fxMfyh9vRj81qm1sbjY0Oy2ZoP7kRG O9lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-transfer-encoding; bh=asGwvdUrTjw8DorufZbYD6ASVjYTNUZUj3WddLs7tLc=; b=auvoaRweom07VRHY2id9Dzz+vDQCLf8JNijVFcGnfZw8PW9iM52BLTsI0LCI5/Y8BT gZsID5Rqx2FDn7BpdfhENQ4Rl5z4gE+gRPmegntAtzqhsXuyv6f1tyj0P9vPhiqSRgRf TIoJxEY1H4QnlvvDZMdgVRXzW3EFcMK1FAECoVS1geSOJHNTKvVcztwdvTc+812q0jEZ kyA9DalBN7IIYBxNuNMVR+gUI6GR4zxX+KtqKwDukNTyu3+1hBHzZRCJUGTlDOxXB9Tv 4IPLlTlcGxJ9RCOzlqwXkpIOXWN9lAPc63z+KwukGBuUeu24XRk3vlewCTtGU7cA6v35 HlHg== X-Gm-Message-State: AOAM533Izbrj+oLXPdjj2koCMBiyznlom2s6VMG28oD4Sq047YDU2k0a yqTBts9X/ipbRJBqXZlPv34= X-Google-Smtp-Source: ABdhPJxJ7ubKRu/WrypYHAj4tnKQ75B3qrAd109dQzRW2f/ksASjEsw1ln6yDUTY0jPlWYKM1Dh/bA== X-Received: by 2002:a65:4c8a:: with SMTP id m10mr12451873pgt.138.1592002386574; Fri, 12 Jun 2020 15:53:06 -0700 (PDT) Received: from localhost ([184.63.162.180]) by smtp.gmail.com with ESMTPSA id nl5sm6912704pjb.36.2020.06.12.15.53.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2020 15:53:05 -0700 (PDT) Date: Fri, 12 Jun 2020 15:52:55 -0700 From: John Fastabend To: Alexei Starovoitov , Jakub Sitnicki Cc: Sabrina Dubroca , Network Development , John Fastabend , Daniel Borkmann , bpf Message-ID: <5ee40747b71ee_489d2af902f845b45d@john-XPS-13-9370.notmuch> In-Reply-To: References: <26038a28c21fea5d04d4bd4744c5686d3f2e5504.1591784177.git.sd@queasysnail.net> <20200612121526.4810a073@toad> Subject: Re: [PATCH bpf] bpf: tcp: recv() should return 0 when the peer socket is closed Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Alexei Starovoitov wrote: > 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 Thanks for the patch. LGTM, I guess we should also break the copy loop in __tcp_bpf_recvmsg if RCV_SHUTDOWN is set it looks like TCP stack does. I'll send a follow up thanks!