From patchwork Mon Aug 7 13:45:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 132075 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:c44e:0:b0:3f2:4152:657d with SMTP id w14csp1490514vqr; Mon, 7 Aug 2023 07:28:54 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGfr543eEXaa/b2x7bzrRf8izy5zu7WSPoQX+h3lSJTXB9REoZgKjWLh1zbDwey4FKfJWRe X-Received: by 2002:a05:6a00:23c5:b0:687:83c8:1425 with SMTP id g5-20020a056a0023c500b0068783c81425mr11806501pfc.0.1691418534583; Mon, 07 Aug 2023 07:28:54 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1691418534; cv=none; d=google.com; s=arc-20160816; b=KuZLIfp41cTorwBeYfgbIbTW1/eTb4i5WDL0YujQAW+t1XuJ99LsrL/+WjVztDdXaX kgtyXC3B9ljpda+Ar9qyCetaFY6iLzsIGK6tZs3aWk1JC3WO91cdJdIheYWr6bC6S7+n RZY8Y7O4175Si1Qp8ZTdq6NCew+nQ/bGaLm+SbgNnGW7WVlDYrQXza6FJJtlvEfjPXnt 4YmkGcISzVQbUPoq2E4Oc/C+YLpZ9qzFcUyBmH8T20dJLwLPLsLqonVn7qZThnWivkKg BRISlOXiRarW1DsW+xkryKwJmKc1KOhYy6GDSweDm2McIbXz2A2gXSPdVe/WpBDY+XVO BJ2Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=VvRHs0oQl+CF4CqoniuHI9S6BlLWdP4X6ChmtvgMCww=; fh=gMFH2stvrvmy061Sc0HEKF4vM70SocLRgs9YiwvSocI=; b=AMrBqOc5zsBXTUaPVsIgui8S3MI04UZTtOFstHnq7eoTpQyr6BxL3SiXNC00xykmNt PdoLDTYQ8qojEvOUbN5w0iEy853cMq2miRmiKv3w2eX/cqw0EhF76NUceAl59KFQA9I6 BcYAN/wAOmW9UVdQN6Y8nWBWEMHKUSdrTYhcg2P8NrNZs0EGbrSjlGHn7lZ7Ya+fQ8bP eEj8u5GZBYkzvFw8kP0IOPVxXBT1Syz7qprwLBRTMWEKjORC2rl0CsI41Uzj35bxYivn IAhxB3UoLRbQ03g7CgUmEZ0m1EYhboxOqAbWXCILAN4XoGAI3ZjQ1ytVmEhuYJ9agfL1 N2gQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b=svAlTn21; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id v10-20020a63610a000000b00563571a8d0esi5542570pgb.858.2023.08.07.07.28.41; Mon, 07 Aug 2023 07:28:54 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b=svAlTn21; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232879AbjHGNrR (ORCPT + 99 others); Mon, 7 Aug 2023 09:47:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232570AbjHGNrQ (ORCPT ); Mon, 7 Aug 2023 09:47:16 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C4A3E53; Mon, 7 Aug 2023 06:47:15 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id d9443c01a7336-1bb84194bf3so29411185ad.3; Mon, 07 Aug 2023 06:47:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1691416035; x=1692020835; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=VvRHs0oQl+CF4CqoniuHI9S6BlLWdP4X6ChmtvgMCww=; b=svAlTn21dkZIGdxfF3T2QxXCXmc4WyXl8RIkqygcuSnC+LWDaDtj5+lXcwzYrEMEVA TjcfsQtcUoyoH0Yx83G1N1pPqw3sEW6J0gqgra+qTz+9Fs/eDNxJziSJrpU8ilu4Qt6c zQqL0qsxmQrSViZcqrm2cioAYMopw9fJV5SFavpRrPgDVrhhYKDP1HlN2+o1Q0yUChzQ QE9DZwTzbX6rbKwhyGePQc2vFOBlXmSaTg03zZbHGpeKbU4Qr2ThpQWXvS19hgXIhKDR mAEg+7cGyHMO+Wtq5OcgWM5x2prFAUEy4jasQvNr22gUZZ67B9ksOHbusDEfwWzKW2aW cRoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691416035; x=1692020835; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=VvRHs0oQl+CF4CqoniuHI9S6BlLWdP4X6ChmtvgMCww=; b=VyDwwfJsd2S5eYApTF3h5ZhOFZX8rVHWsKJvv2NdJJliy0B7CAjX3gz7WzEdegAL2u rfxM7U111RNZmW3au5jhRSBk18Wwzjz0nSrogE+61lc2FCiFYKdLVj4Xi0qmZWMzUE0l vRZzQq60v82hartPyZMxv4MWoDRn4xEoNfQc8VjRGNFypZN1bYJzLisSgyMGOrTqs84j 37WwfwrQr9b9nTHWk8UFNN4eDXC49EUix1r2ZcXZb3DV/uabnM3q/kTL16Nb3N2AppSO w0JTlxmO5wWpeWSb10gfQeXegYRs7rjJhdTOt9GEGoclZmPosvmDDHR5QW1X8yARD8Er RMUw== X-Gm-Message-State: AOJu0YxwKh5vEx4IU3r3S4QRFfaFgREYLfeto2UHaeh8RMGJUcjumR3t /B3p7YL1OI2dRx8cjZn1lKg= X-Received: by 2002:a17:902:b20e:b0:1bb:6eeb:7a08 with SMTP id t14-20020a170902b20e00b001bb6eeb7a08mr8812654plr.10.1691416034543; Mon, 07 Aug 2023 06:47:14 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.23]) by smtp.gmail.com with ESMTPSA id h2-20020a170902704200b001b54a88e4a6sm6912097plt.51.2023.08.07.06.47.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Aug 2023 06:47:14 -0700 (PDT) From: menglong8.dong@gmail.com X-Google-Original-From: imagedong@tencent.com To: edumazet@google.com, ncardwell@google.com Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Menglong Dong Subject: [PATCH net-next v2 1/3] net: tcp: send zero-window ACK when no memory Date: Mon, 7 Aug 2023 21:45:45 +0800 Message-Id: <20230807134547.2782227-2-imagedong@tencent.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230807134547.2782227-1-imagedong@tencent.com> References: <20230807134547.2782227-1-imagedong@tencent.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1773580881494942699 X-GMAIL-MSGID: 1773580881494942699 From: Menglong Dong For now, skb will be dropped when no memory, which makes client keep retrans util timeout and it's not friendly to the users. In this patch, we reply an ACK with zero-window in this case to update the snd_wnd of the sender to 0. Therefore, the sender won't timeout the connection and will probe the zero-window with the retransmits. Signed-off-by: Menglong Dong --- v2: - send 0 rwin ACK for the receive queue empty case when necessary - send the ACK immediately by using the ICSK_ACK_NOW flag --- include/net/inet_connection_sock.h | 3 ++- net/ipv4/tcp_input.c | 14 +++++++++++--- net/ipv4/tcp_output.c | 14 +++++++++++--- 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index c2b15f7e5516..be3c858a2ebb 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -164,7 +164,8 @@ enum inet_csk_ack_state_t { ICSK_ACK_TIMER = 2, ICSK_ACK_PUSHED = 4, ICSK_ACK_PUSHED2 = 8, - ICSK_ACK_NOW = 16 /* Send the next ACK immediately (once) */ + ICSK_ACK_NOW = 16, /* Send the next ACK immediately (once) */ + ICSK_ACK_NOMEM = 32, }; void inet_csk_init_xmit_timers(struct sock *sk, diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8e96ebe373d7..aae485d0a3b6 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5059,12 +5059,20 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) /* Ok. In sequence. In window. */ queue_and_out: - if (skb_queue_len(&sk->sk_receive_queue) == 0) - sk_forced_mem_schedule(sk, skb->truesize); - else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) { + if (skb_queue_len(&sk->sk_receive_queue) == 0) { + if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) { + sk_forced_mem_schedule(sk, skb->truesize); + inet_csk(sk)->icsk_ack.pending |= + (ICSK_ACK_NOMEM | ICSK_ACK_NOW); + inet_csk_schedule_ack(sk); + } + } else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) { reason = SKB_DROP_REASON_PROTO_MEM; NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP); sk->sk_data_ready(sk); + inet_csk(sk)->icsk_ack.pending |= + (ICSK_ACK_NOMEM | ICSK_ACK_NOW); + inet_csk_schedule_ack(sk); goto drop; } diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index c5412ee77fc8..769a558159ee 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -257,11 +257,19 @@ EXPORT_SYMBOL(tcp_select_initial_window); static u16 tcp_select_window(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); - u32 old_win = tp->rcv_wnd; - u32 cur_win = tcp_receive_window(tp); - u32 new_win = __tcp_select_window(sk); struct net *net = sock_net(sk); + u32 old_win = tp->rcv_wnd; + u32 cur_win, new_win; + + /* Make the window 0 if we failed to queue the data because we + * are out of memory. The window is temporary, so we don't store + * it on the socket. + */ + if (unlikely(inet_csk(sk)->icsk_ack.pending & ICSK_ACK_NOMEM)) + return 0; + cur_win = tcp_receive_window(tp); + new_win = __tcp_select_window(sk); if (new_win < cur_win) { /* Danger Will Robinson! * Don't update rcv_wup/rcv_wnd here or else From patchwork Mon Aug 7 13:45:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 132069 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:c44e:0:b0:3f2:4152:657d with SMTP id w14csp1486949vqr; Mon, 7 Aug 2023 07:23:24 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE/7Pd1iDq0jMvVsbYuA2tRs3/eaFNJMUxNTEuFhrSOQCidwN55mx/7NCRRN+yMOQb46ybt X-Received: by 2002:a17:906:7490:b0:993:f744:d230 with SMTP id e16-20020a170906749000b00993f744d230mr8312030ejl.16.1691418204163; Mon, 07 Aug 2023 07:23:24 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1691418204; cv=none; d=google.com; s=arc-20160816; b=ZtH07HU9HgFKEFqtBkl19BjPW+nzyJUVLOZs7Y8rHAw/0aWFobU6YvqVSqZZXyKlZ6 T/0M3HJvNh6+wdqM1Q6fnC3oglDULSj+m0mo3wHMKUNGTMq2A5WmWRY5k8LICfqOp4l4 z1kx4zq4DXBXCe45sahjmRODQ2idbUMNS6fhCkyaNSZ2uqHPbb1JQFSrGTh1RwbGNSI0 GJWbn2F+NBNbpzf/Y8gYJe6JVinits1nn4P/MauOu/tFbqXp/cHeGsXDdTZx4tzQNYXf hGAAlmKKBmcObVeEEUWnF3HDqHCyRZSTB76C2rY03oHVW9xqkYsd6dD4BPUm21xCA2iU VPEQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=ujZiVs9WYzU9nGaUspRh3pJHwz3VwVmUv7LZdW5BRhE=; fh=gMFH2stvrvmy061Sc0HEKF4vM70SocLRgs9YiwvSocI=; b=pjrpcN8PQwEaKO+Dra3xieM9s3k0sXDYSCD0FgbxUZXpf43PhOcSVKKyiw7V8GyitX /YMkixa0F4Qwwp3Cni0P9PUk8K+ddV8JOc8XIsx8WfLq80wQOBaFDBx51DpmKuEOSPsM YcOA3muwjO5kyO9T2ri5twJwjvu5/ubuRa4YiQUk3osW++Xeb4brXMGJdbcJbWgi+Uwt ZS9LLsjDfvzokl2jfr1yCfNOClATIBj9jq0t+exaA3e5Trw3RV1yq+3zuQnYPphpXN1G 2sQJ3eS9gRinYLxmwB3QCCc0digkniyhEiE0cQK600Ex+E8TQtTZHToyiu2rcotq4cAz 1Kzg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b="QiU/70y8"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. 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This is for the case that the receiver replies an zero-window ACK when it is under memory stress and can't queue the new data. Signed-off-by: Menglong Dong --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index aae485d0a3b6..f17cca362086 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3525,7 +3525,7 @@ static inline bool tcp_may_update_window(const struct tcp_sock *tp, { return after(ack, tp->snd_una) || after(ack_seq, tp->snd_wl1) || - (ack_seq == tp->snd_wl1 && nwin > tp->snd_wnd); + (ack_seq == tp->snd_wl1 && (nwin > tp->snd_wnd || !nwin)); } /* If we update tp->snd_una, also update tp->bytes_acked */ From patchwork Mon Aug 7 13:45:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 132170 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:c44e:0:b0:3f2:4152:657d with SMTP id w14csp1528488vqr; Mon, 7 Aug 2023 08:29:40 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFUag9z6w7AOJpVpkSNCSFtKVM8iy0L2BDecIMLpNO+IDdg3xwZv9VN2RctwdLYD7hFtv6V X-Received: by 2002:a17:906:319b:b0:966:17b2:5b0b with SMTP id 27-20020a170906319b00b0096617b25b0bmr7862768ejy.49.1691422180383; Mon, 07 Aug 2023 08:29:40 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1691422180; cv=none; d=google.com; s=arc-20160816; b=mc1Npbga616br8w26WaXMfuPU8tGEKGHDAZt2HbUG1HBWx8vGsVFxo2y/Fh+pL4MWs Ov20FDKL4UxWJ5WX1PiAI5Ez4sX7YneZSIq4zImJplhMuCEZrNR4WAy2clndCQvLh0tY CKGdDUqn7mVphdw2mgIjoPKJ4NaqFE9EGwESx+V/kWSJKS6ypx+XdNo9c69Efu49kvOF 7hF4BefmPTL05Y0V8qjdIKo908xFYSuTm1c9mPeNN3lWKaVAFcPWcDPKVvezoHS5unQn +BWhkUnkWqyUzKDQsRt27Budfdhs7URBAD9uvQDExi6dBMXChlZr1SDm9UTN2Y9Ov/0L H0DA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=hO5ffsMV1x2LeSF6TZmYSUDXcFSKo+pDvUEfomBe2w0=; fh=gMFH2stvrvmy061Sc0HEKF4vM70SocLRgs9YiwvSocI=; b=ZhWygFmwHBUkeR/Kgk5Tfbb9wrnF50C/ZpzAs+scib9Z1x8+J1EUR5LJmzLLn6N9OL DeByMmlRYFDoluxkk/bq6KG1hbYLr2X00oOqJPTilx58TDr3zjsimChDcHY09gGV0OTW LCswQ721mWjiwhm0vNdo06h1+h7TMab5eHAcsMsN9YVtOvVMlvSUTHmOQthc0ioyWxON VPtuerM5JPDtsqyW2dBGzmetKJeXPmcVOsNtPPT6VNv/+Sh3hgOgGXqYCsRW41iQUd2r CpCWr18Nahq9P/nNaFmCW0FuiPyZu8vLNZ6p0O/s6j0ChHV4aljX/bbYLFrhKKBveKiL fN3g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b=m8bkI8TH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. 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This is not right all the time. The retransmits will become zero-window probes in tcp_retransmit_timer() if the 'snd_wnd==0'. Therefore, the icsk->icsk_rto will come up to TCP_RTO_MAX sooner or later. However, the timer is not precise enough, as it base on timer wheel. Sorry that I am not good at timer, but I know the concept of time-wheel. The longer of the timer, the rougher it will be. So the timeout is not triggered after TCP_RTO_MAX, but 122877ms as I tested. Therefore, 'tcp_jiffies32 - tp->rcv_tstamp > TCP_RTO_MAX' is always true once the RTO come up to TCP_RTO_MAX, and the socket will die. Fix this by replacing the 'tcp_jiffies32' with '(u32)icsk->icsk_timeout', which is exact the timestamp of the timeout. Meanwhile, using "max(tp->retrans_stamp, tp->rcv_tstamp)" as the last updated timestamp in the receiving path, as "tp->rcv_tstamp" can restart from idle, then tp->rcv_tstamp could already be a long time (minutes or hours) in the past even on the first RTO. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/netdev/CADxym3YyMiO+zMD4zj03YPM3FBi-1LHi6gSD2XT8pyAMM096pg@mail.gmail.com/ Signed-off-by: Menglong Dong --- v2: - consider the case of the connection restart from idle, as Neal comment --- net/ipv4/tcp_timer.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index d45c96c7f5a4..e4b2d8706cae 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -454,6 +454,14 @@ static void tcp_fastopen_synack_timer(struct sock *sk, struct request_sock *req) req->timeout << req->num_timeout, TCP_RTO_MAX); } +static bool tcp_rtx_probe0_timed_out(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + u32 last_ts; + + last_ts = max(tp->retrans_stamp, tp->rcv_tstamp); + return inet_csk(sk)->icsk_timeout - last_ts > TCP_RTO_MAX; +} /** * tcp_retransmit_timer() - The TCP retransmit timeout handler @@ -519,7 +527,7 @@ void tcp_retransmit_timer(struct sock *sk) tp->snd_una, tp->snd_nxt); } #endif - if (tcp_jiffies32 - tp->rcv_tstamp > TCP_RTO_MAX) { + if (tcp_rtx_probe0_timed_out(sk)) { tcp_write_err(sk); goto out; }