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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 080AEC4167E for ; Mon, 15 Nov 2021 23:47:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDC1E61BE2 for ; Mon, 15 Nov 2021 23:47:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356257AbhKOXte (ORCPT ); Mon, 15 Nov 2021 18:49:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:45222 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344161AbhKOTXz (ORCPT ); Mon, 15 Nov 2021 14:23:55 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A40AB632A6; Mon, 15 Nov 2021 18:52:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637002380; bh=ZthVkNfp1aBMaQGDLnuqGuaUv33dpWzeRJ1vmLT2fes=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bmRYk8+Cy736aMRVa7d/bc5y5PrKfD+6qD8/uTnQfPTpbVzdj+ISvKY0nHecvXiI5 7tU9ncbRmaWaZp6yifc6QEQGcindeIdlBnefFybBSEte3/pRw/EzEQlb73zVsjM4cM JIWtqQzr/mWiy5YXiwurONXwA6egA0zx4EFwRiE8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xin Long , "David S. Miller" , Sasha Levin Subject: [PATCH 5.15 544/917] sctp: subtract sctphdr len in sctp_transport_pl_hlen Date: Mon, 15 Nov 2021 18:00:39 +0100 Message-Id: <20211115165447.204080560@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165428.722074685@linuxfoundation.org> References: <20211115165428.722074685@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xin Long [ Upstream commit cc4665ca646c96181a7c00198aa72c59e0c576e8 ] sctp_transport_pl_hlen() is called to calculate the outer header length for PL. However, as the Figure in rfc8899#section-4.4: Any additional headers .--- MPS -----. | | | v v v +------------------------------+ | IP | ** | PL | protocol data | +------------------------------+ <----- PLPMTU -----> <---------- PMTU --------------> Outer header are IP + Any additional headers, which doesn't include Packetization Layer itself header, namely sctphdr, whereas sctphdr is counted by __sctp_mtu_payload(). The incorrect calculation caused the link pathmtu to be set larger than expected by t->pl.pmtu + sctp_transport_pl_hlen(). This patch is to fix it by subtracting sctphdr len in sctp_transport_pl_hlen(). Fixes: d9e2e410ae30 ("sctp: add the constants/variables and states and some APIs for transport") Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/sctp/sctp.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index bc00410223b03..189fdb9db1622 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -626,7 +626,8 @@ static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize) static inline int sctp_transport_pl_hlen(struct sctp_transport *t) { - return __sctp_mtu_payload(sctp_sk(t->asoc->base.sk), t, 0, 0); + return __sctp_mtu_payload(sctp_sk(t->asoc->base.sk), t, 0, 0) - + sizeof(struct sctphdr); } static inline void sctp_transport_pl_reset(struct sctp_transport *t) -- 2.33.0