From nobody Sat Jun 13 11:22:20 2026 Received: from mail-dl1-f97.google.com (mail-dl1-f97.google.com [74.125.82.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C56683B583E for ; Thu, 7 May 2026 15:51:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.97 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778169109; cv=none; b=dFf/O5ERbnf2blc50q8s7iVGm+6LKy5zl27+nA2/Xz695mDp2nUOt9NflDu1D5RFSNmxzJPk7QvIOTZYBETKqxSz1AVOWqm+ln8yyB+9/xzDXzdY/+TtvtKPS1ufTbh/u3QF707nzSCzOvHZ/fP6EFBl3gQi7IpFLFZOEcO1HHk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778169109; c=relaxed/simple; bh=M15uTKwN3yvrhy6+C4e1xest8u1tFHkbzRM6zHTj0ow=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YOz97G+MupPEi0p1wa3WpFzxz7+FclfZRLx1IPhUpRkgfPBJ6WpKOFnZdDE8cBval45Vu9tnbX5s10lDl6v2ddGPY0DZwSvWe07l+9cEI1OV83OcAIXDmWcf07q95BWrBTuYqFljRyLGUnqTjzOd/Z0tiFx3NCrg0SJqvrLrWT8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com; spf=fail smtp.mailfrom=broadcom.com; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b=Gdxekxqm; arc=none smtp.client-ip=74.125.82.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=broadcom.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="Gdxekxqm" Received: by mail-dl1-f97.google.com with SMTP id a92af1059eb24-12dc9b6beceso38637c88.1 for ; Thu, 07 May 2026 08:51:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778169107; x=1778773907; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BtLl8kOWvPMx0S+t/a7Mz9vgLX46fqlMMw8qeaNu9sU=; b=UsnzuMgQ4E8qTuttfKaA5MaVurKwYzQ+6Q72OdCzVMOwkJxbw1RyV0CA0CtJ5XXfuU XY/w1FQUo3l+lNsnfyRgLTnsAdsTWCP+RgaEAr1XB3d1BS3SLR94Ewf//cGAZ2CFEHW3 aBDoBDCmIqWAorm/wDf9z2k51pahTJLwYellsiQldOCiGYB8dTzjMscx5HMU/5DaCA0R pS24A/3QuvKhJPPLHoIXTMTiTzUdkHwnxAUM+SyWYMuVQVQ4CJg+V/TttjTDB8rsrEXd iWBi7+ZiNHlZU1Y1fDHf2UjbUWBxOgmo9tMAoivu+Q3Qc90qWqzY9foxV6oSFDLIeWfW If3w== X-Forwarded-Encrypted: i=1; AFNElJ9yuwgr1LyubiEp7ErF6iwOKsT9UYoalRfcPyeD6vZl+ok/ABWTFAbStBzFDLGM1P6+7Kcmi2QxME3IJmQ=@vger.kernel.org X-Gm-Message-State: AOJu0YyzBMn6XS1Lr8ghYqJcoIutcfIcFcRLBVZxwqwaXjhUeZjCkVLm 6BWJLmE5zKTJJI5MeVXaZD4Z25mlP0ovnGtBmBrErtWtVbbASbjdVr0H9PVEkF8Dek72UcOve9K MGavD1ubijuh7KZBUa/4fHMcAlWH5O0KRnB/btlHX3ql11/K0ZsRF1EuoZgepOh0Mt+hToHYBoM C6krFhq3tsF9IcDUXC3XNAkIj9Fo4GExNMCvEXW7DHKMkUvpm67HJjizbo2nXa+4IqHQyyWJ74e injnfq5l6hMCW8vZPmxg7g= X-Gm-Gg: AeBDietj4NFgDYMIrOLk4NOiPPP8SSkn4uL/Dac21NLPThx297aog2OqhheK4jYYi4K Uj5D6o+z4CDgcU1ebeN0ryoh59HOPhFOmfOmD9yZhZvH0KFRadGaDrsGW/iMX1xvweawcxN3v9F kxghSSRQgF1STDoxXTUs4xKwb06Kl0nsSrd2Fjk5UJgcAiL7cD1oUnPe7t4Aw9BleBPeihzYurm wJvNgsVsVha0OonfvFi/cixMpQG3nTBQUv8n6qgApVYArAVNBcCu4jmw1bEeGyLRhC/LCC8qdr4 Fkl6ZiUd882lCVT6pjnNcMG5e9p3jgtzd80tkdZVmQewrmUmQxbBXwvENNBRFRT/cAVDKe36cN7 LiniLdsYyfmH1pw+iNtQzhiHYQIl7a6NfpvkpCRa2k+9cft8nFFdZSlRFsUOAn046+DIN8ggxX3 cT13E3zFsaMPrBWNdXDIZQEhU3yo5CzP7j/i/90J3k+giVYE9tjXlYsGVJvQ== X-Received: by 2002:a05:7022:2212:b0:130:8ed9:203e with SMTP id a92af1059eb24-1320ab4df9fmr1852325c88.0.1778169106518; Thu, 07 May 2026 08:51:46 -0700 (PDT) Received: from smtp-us-east1-p01-i01-si01.dlp.protect.broadcom.com (address-144-49-247-21.dlp.protect.broadcom.com. [144.49.247.21]) by smtp-relay.gmail.com with ESMTPS id a92af1059eb24-131f99a5b1esm443089c88.3.2026.05.07.08.51.46 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 May 2026 08:51:46 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-qk1-f198.google.com with SMTP id af79cd13be357-8d59968444aso27795285a.3 for ; Thu, 07 May 2026 08:51:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1778169105; x=1778773905; darn=vger.kernel.org; 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=BtLl8kOWvPMx0S+t/a7Mz9vgLX46fqlMMw8qeaNu9sU=; b=GdxekxqmEJ3Rx7hl0zllmscamtHQJ4J7UOFpKkbkp8NKpIqdhNX+OiXH8X/Hzzob18 TOwtRgpjTi54fGeYUicnI7/N8nW+9bJkSWnn5Mq9B0SwpwsuqYoe/1R0HSqV2tb8ALB8 RePp0S+PgS1JWMB0e6eANZfN4feGMDtfAbuV8= X-Forwarded-Encrypted: i=1; AFNElJ8Q5u+FqYx0XlapnvyhxvTg7pqMg9VfZtwCdYjNVSo0SJsCLzhS4RjktrSzqCissbjYUCtIJ2fbVLkSaUU=@vger.kernel.org X-Received: by 2002:a05:620a:4406:b0:8cf:d953:b4ec with SMTP id af79cd13be357-9051dafefc0mr754137685a.3.1778169105095; Thu, 07 May 2026 08:51:45 -0700 (PDT) X-Received: by 2002:a05:620a:4406:b0:8cf:d953:b4ec with SMTP id af79cd13be357-9051dafefc0mr754133685a.3.1778169104463; Thu, 07 May 2026 08:51:44 -0700 (PDT) Received: from photon-d7fac424c0d3 ([192.19.161.250]) by smtp.gmail.com with ESMTPSA id af79cd13be357-90642b76d39sm240711885a.2.2026.05.07.08.51.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 May 2026 08:51:44 -0700 (PDT) From: Ankit Jain To: edumazet@google.com, netdev@vger.kernel.org Cc: kuba@kernel.org, davem@davemloft.net, pabeni@redhat.com, ncardwell@google.com, kuniyu@google.com, horms@kernel.org, shuah@kernel.org, quic_subashab@quicinc.com, quic_stranche@quicinc.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, karen.badiryan@broadcom.com, ajay.kaher@broadcom.com, alexey.makhalov@broadcom.com, vamsi-krishna.brahmajosyula@broadcom.com, yin.ding@broadcom.com, tapas.kundu@broadcom.com, Ankit Jain Subject: [PATCH net v3 1/2] tcp: protect locked SO_RCVBUF from Silly Window Syndrome Date: Thu, 7 May 2026 15:48:05 +0000 Message-ID: <20260507154806.18635-2-ankit-aj.jain@broadcom.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260507154806.18635-1-ankit-aj.jain@broadcom.com> References: <20260507154806.18635-1-ankit-aj.jain@broadcom.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e Content-Type: text/plain; charset="utf-8" When an application locks SO_RCVBUF, it disables TCP window auto-tuning. However, the kernel still applies dynamic truesize penalties to the scaling_ratio. For small packets, this penalty drops the scaling_ratio to 1. This reduces the advertised window and causes Silly Window Syndrome (SWS) along with 504 Gateway Timeouts in applications like Tomcat. This patch bypasses the truesize penalty if SOCK_RCVBUF_LOCK is set. To prevent memory exhaustion from large aggregate payloads, the penalty is still applied for GRO packets (skb->len > len). Fixes: a2cbb1603943 ("tcp: Update window clamping condition") Reported-by: Karen Badiryan Signed-off-by: Ankit Jain --- net/ipv4/tcp_input.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index d5c9e65d9760..4b1832b3face 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -240,8 +240,13 @@ static void tcp_measure_rcv_mss(struct sock *sk, const= struct sk_buff *skb) /* Note: divides are still a bit expensive. * For the moment, only adjust scaling_ratio * when we update icsk_ack.rcv_mss. + * + * Bypass truesize penalty for locked SO_RCVBUF to prevent + * window collapse. Still apply it to GRO packets. */ - if (unlikely(len !=3D icsk->icsk_ack.rcv_mss)) { + if (unlikely(len !=3D icsk->icsk_ack.rcv_mss && + (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK) || + skb->len > len))) { u64 val =3D (u64)skb->len << TCP_RMEM_TO_WIN_SCALE; u8 old_ratio =3D tcp_sk(sk)->scaling_ratio; =20 --=20 2.53.0 From nobody Sat Jun 13 11:22:20 2026 Received: from mail-oo1-f98.google.com (mail-oo1-f98.google.com [209.85.161.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E4EE244B67A for ; Thu, 7 May 2026 15:51:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.98 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778169117; cv=none; b=kTKXFvYdeytJuWuR5PPBdSilHxdIRFuionKsVEkpHYXpFTT9vRR+itx7H0of3rNzSnTNxwPt8GqB1aayuOhbqZ9JPbmN40l/fw4lmjj3fwv8c8DQxDUq0Hx+P3UbvDaebeXxyv7fA8IfcEXo/ghHkYXh+xEEnDyxmGTFmrDMAoo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778169117; c=relaxed/simple; bh=N/c5QH2LpQTCnVMZjv55xEfP1S6t/HG0AX5pqSkBqBE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D9vLjtIlnMtScr/f/yRXxfhA70rfGEhXsIYTJRbjwBKf0p9d4wZNzFSF0rbK4qMxY8r9GX6YtdmzmYMtp0C+bIMwjLj2jb6empbNYej3mMvWjlAlkPaGh9hIIQuERAKJsG49MZECvZHTLyt/63AKUuppJ/IojosalFv/7oW4ADg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com; spf=fail smtp.mailfrom=broadcom.com; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b=FVziDCaZ; arc=none smtp.client-ip=209.85.161.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=broadcom.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="FVziDCaZ" Received: by mail-oo1-f98.google.com with SMTP id 006d021491bc7-6981f0b9b30so33341eaf.1 for ; Thu, 07 May 2026 08:51:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778169114; x=1778773914; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=3Gej9rC0V5wj21YK/OT0tP6dMq4zLV0oZtuZHtg6JDU=; b=mOj/oG9ya5f5NxQMTsg24q6k9hl3VkmyUMPHMKjSfpdz8SvwKu3RvzWpJHSAIT4UPR 35eoYvx/KM4+KfpweovAC/qT8Xmutmq1fqNzxEoZ9OGyP7TFiguxqtNomyiocsEKDssB amVT1Dat4/hAikDB4kTBmTrZFShUQzc2fbLCkEyv6wUl9z01C0Vcq1KSYvwppAVe2/8l rObDOLXyf6u32y/QFv4BJiMCmhBFMA1RQYhR1gi4er++b/phqLUkW+NVsMtmWZ0fmjuf zBLqSiAr4OFF+s0d8Dn63X1LScG5RPr2dV8TVP8LVOCQqarMGLkffBRdJRv/RiwQrf38 zXpA== X-Forwarded-Encrypted: i=1; AFNElJ/Sa82N21cgJ7hofVvrdv/HqUhfzlhAgrv2dryPyzKQKo9KcY71EtTyy6qNf4gLaRdG2oOdeOBaOoTSTpo=@vger.kernel.org X-Gm-Message-State: AOJu0YygXEd/oAdVwREpTHS1bjRGu60Ik+/MSyjzOT6kDscxd5B+STb0 7wcOPosb/Ywa99U1+zYzzBS/MvfLkdnray3Mf0ps9gnY9+znRSiwAi5F84TYOORLU722AMpAeAJ 4EwK9Wu5fpMfbnN/yXw1pfDQp/z0U/f1f0mQeOPyvoNEytmvRbygIxEg6LiuEN8oGb/ygg9FOmq J9Bneckr/36zimjlKHcB33XvMsvAiwQnotvecfzFuUjWxTGyBPm5axGUFhWu5kNglLIqfiIxoXC w873afR5/25NIb+PfJiK6Q= X-Gm-Gg: AeBDies9ni1nojE1pyqjd7/S+Zy/nRVLdzQRtKPNjAOmdI3IAs3TwzsEXuqt5XCJ/0e J0aFOvjPAoAlj581QsFRxYsZG3BSamlVQJ5Tlv80aBjc/D49RrnIirpmIEo7zvhLFMQOv5JqfJF DszG4Pey1PrJHXA2RslQyBDKWezZAcOxrJeYMHI8nUqgd5zWIWsepcTIJF2+yfRw2Y5KUKscPqd kgIAQnI66/nMrUe4vMwwecztKPJb+A6Mp1mQtQHm8GXdW6r31Yz9q+kDeep15yawNVOUDRbxtz0 sJneXDSS4obRHll6Mo32BmhJVo9BzrKlChcfS7XjlQCs1ES9Zqo5tlzOm6jrq08fSJz2zMPBYIg FHPlz07qrOgZ89kRS8jYTh4lGvi55SFNX4Qap/1JKdO0IMGRmZ0BzDG98t3+NVeZlCzeg3ljxZE QyVdjwEpeHvdrwlXtOU6wRcbCOnYPE73/oZmaMLvzRhD8Hbygk4iJl+G9eK7VVnJQSR0b8 X-Received: by 2002:a05:6820:201b:b0:694:9c8c:d2a9 with SMTP id 006d021491bc7-69998d27d29mr2787905eaf.2.1778169113795; Thu, 07 May 2026 08:51:53 -0700 (PDT) Received: from smtp-us-east1-p01-i01-si01.dlp.protect.broadcom.com (address-144-49-247-21.dlp.protect.broadcom.com. [144.49.247.21]) by smtp-relay.gmail.com with ESMTPS id 006d021491bc7-696894ce108sm1159405eaf.16.2026.05.07.08.51.53 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 May 2026 08:51:53 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-qk1-f198.google.com with SMTP id af79cd13be357-8eab57f0e8bso27614085a.0 for ; Thu, 07 May 2026 08:51:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1778169113; x=1778773913; darn=vger.kernel.org; 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=3Gej9rC0V5wj21YK/OT0tP6dMq4zLV0oZtuZHtg6JDU=; b=FVziDCaZt9A7Icol0tsQQITtIfwOK/o7xP5yLgiX2GJVx+0cqGOBw+GuDXuJGQJiPx yLRqm5IoYHFUSl/29gYTFci8pnlywIs463JIHfdb5x2n6OI313D+T26Qcy/Kt5XeCm1W XI+SffGrUPe3r470jHOz0HeKFKa+dRG0IgMTw= X-Forwarded-Encrypted: i=1; AFNElJ9roRGT5GVaHKZVnFBpNkKinods3ypi9dMf1rOvPJke2aQeK1BmjfJucfEVIUW7gKKvCBHNUdiHJBqNYw0=@vger.kernel.org X-Received: by 2002:a05:620a:3195:b0:8ea:c7a8:5065 with SMTP id af79cd13be357-904d4392205mr887325385a.2.1778169112802; Thu, 07 May 2026 08:51:52 -0700 (PDT) X-Received: by 2002:a05:620a:3195:b0:8ea:c7a8:5065 with SMTP id af79cd13be357-904d4392205mr887320985a.2.1778169112144; Thu, 07 May 2026 08:51:52 -0700 (PDT) Received: from photon-d7fac424c0d3 ([192.19.161.250]) by smtp.gmail.com with ESMTPSA id af79cd13be357-90642b76d39sm240711885a.2.2026.05.07.08.51.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 May 2026 08:51:51 -0700 (PDT) From: Ankit Jain To: edumazet@google.com, netdev@vger.kernel.org Cc: kuba@kernel.org, davem@davemloft.net, pabeni@redhat.com, ncardwell@google.com, kuniyu@google.com, horms@kernel.org, shuah@kernel.org, quic_subashab@quicinc.com, quic_stranche@quicinc.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, karen.badiryan@broadcom.com, ajay.kaher@broadcom.com, alexey.makhalov@broadcom.com, vamsi-krishna.brahmajosyula@broadcom.com, yin.ding@broadcom.com, tapas.kundu@broadcom.com, Ankit Jain Subject: [PATCH net v3 2/2] selftests/net: add packetdrill test for locked SO_RCVBUF SWS Date: Thu, 7 May 2026 15:48:06 +0000 Message-ID: <20260507154806.18635-3-ankit-aj.jain@broadcom.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260507154806.18635-1-ankit-aj.jain@broadcom.com> References: <20260507154806.18635-1-ankit-aj.jain@broadcom.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e Content-Type: text/plain; charset="utf-8" Add a packetdrill test to verify that locked SO_RCVBUF sockets do not suffer from scaling_ratio truesize penalties. The test uses a standard 1460 MSS and sends medium-sized packets (600, 700, 800 bytes) to trigger the recalculation logic. It checks that the internal window clamp (tcpi_rcv_ssthresh) does not drop unexpectedly. Signed-off-by: Ankit Jain --- .../net/packetdrill/tcp_locked_rcvbuf_sws.pkt | 29 +++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 tools/testing/selftests/net/packetdrill/tcp_locked_rcvb= uf_sws.pkt diff --git a/tools/testing/selftests/net/packetdrill/tcp_locked_rcvbuf_sws.= pkt b/tools/testing/selftests/net/packetdrill/tcp_locked_rcvbuf_sws.pkt new file mode 100644 index 000000000000..43e1d00d5f26 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_locked_rcvbuf_sws.pkt @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test that TCP does not reduce scaling_ratio for locked SO_RCVBUF. + +0 socket(..., SOCK_STREAM, IPPROTO_TCP) =3D 3 ++0 setsockopt(3, SOL_SOCKET, SO_RCVBUF, [32768], 4) =3D 0 ++0 bind(3, ..., ...) =3D 0 ++0 listen(3, 1) =3D 0 + +// Establish connection with standard MSS. ++0 < S 0:0(0) win 65535 ++0 > S. 0:0(0) ack 1 <...> ++0 < . 1:1(0) ack 1 win 65535 ++0 accept(3, ..., ...) =3D 4 + +// Inject varying payload sizes to force scaling_ratio recalculation. ++0.1 < P. 1:601(600) ack 1 win 65535 ++0 > . 1:1(0) ack 601 <...> + ++0.1 < P. 601:1301(700) ack 1 win 65535 ++0 > . 1:1(0) ack 1301 <...> + ++0.1 < P. 1301:2101(800) ack 1 win 65535 ++0 > . 1:1(0) ack 2101 <...> + +// Check that truesize penalty did not reduce the window clamp. +// On unpatched kernels, rcv_ssthresh drops to ~22K. ++0.1 %{ +assert tcpi_rcv_ssthresh > 28000, f"rcv_ssthresh dropped unexpectedly: {tc= pi_rcv_ssthresh}" +}% --=20 2.53.0