From patchwork Tue May 12 14:08:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 219424 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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS 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 9FDCCC54E8D for ; Tue, 12 May 2020 14:11:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7DF8220722 for ; Tue, 12 May 2020 14:11:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Tq5uKEl6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730209AbgELOLT (ORCPT ); Tue, 12 May 2020 10:11:19 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:52648 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728085AbgELOLT (ORCPT ); Tue, 12 May 2020 10:11:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589292677; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=t6r+aWF2mByE1BEe/eFrEtGteU5NwcU6UeHrM2x9QnA=; b=Tq5uKEl6bSw/EMSZ1T4pVg98TLAL/lrxXcLm6irPABQvwcRXqpp9O68VeDH4I4Zv+kSP00 u5Qvc0Jf4xy2HMEzZC8c3MRdWZOk4x/V4g/ueNgQ1mRqUI8+ozE6Sxj13Mc51saXpw95mu Jp5ZzX4RdaJ7YAVOGwrq1wHJa8m9Eeg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-178-i0RdEZBFOo2iAA5P6Yn-SQ-1; Tue, 12 May 2020 10:11:15 -0400 X-MC-Unique: i0RdEZBFOo2iAA5P6Yn-SQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0AC791083E8B; Tue, 12 May 2020 14:11:14 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-115-10.ams2.redhat.com [10.36.115.10]) by smtp.corp.redhat.com (Postfix) with ESMTP id D7D2E5D9DD; Tue, 12 May 2020 14:11:12 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: Eric Dumazet , "David S. Miller" , Christoph Paasch Subject: [RFC PATCH 1/3] mptcp: add new sock flag to deal with join subflows Date: Tue, 12 May 2020 16:08:08 +0200 Message-Id: <81c3f2f857c2e68e22f8e8b077410ffd2960a29f.1589280857.git.pabeni@redhat.com> In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org MP_JOIN subflows must not land into the accept queue. Currently tcp_check_req() calls an mptcp specific helper to detect such scenario. Such helper leverages the subflow context to check for MP_JOIN subflows. We need to deal also with MP JOIN failures, even when the subflow context is not available due to allocation failure. A possible solution would be changing the syn_recv_sock() signature to allow returning a more descriptive action/ error code and deal with that in tcp_check_req(). Since the above need is MPTCP specific, this patch instead uses a TCP socket hole to add an MPTCP specific flag. Such flag is used by the MPTCP syn_recv_sock() to tell tcp_check_req() how to deal with the request socket. This change is a no-op for !MPTCP build, and makes the MPTCP code simpler. It allows also the next patch to deal correctly with MP JOIN failure. Signed-off-by: Paolo Abeni --- include/linux/tcp.h | 1 + include/net/mptcp.h | 17 ++++++++++------- net/ipv4/tcp_minisocks.c | 2 +- net/mptcp/protocol.c | 7 ------- net/mptcp/subflow.c | 2 ++ 5 files changed, 14 insertions(+), 15 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index e60db06ec28d..dc12c59db41e 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -385,6 +385,7 @@ struct tcp_sock { */ #if IS_ENABLED(CONFIG_MPTCP) bool is_mptcp; + bool drop_req; #endif #ifdef CONFIG_TCP_MD5SIG diff --git a/include/net/mptcp.h b/include/net/mptcp.h index e60275659de6..c4809c24a185 100644 --- a/include/net/mptcp.h +++ b/include/net/mptcp.h @@ -68,6 +68,11 @@ static inline bool rsk_is_mptcp(const struct request_sock *req) return tcp_rsk(req)->is_mptcp; } +static inline bool sk_drop_req(const struct sock *sk) +{ + return tcp_sk(sk)->is_mptcp && tcp_sk(sk)->drop_req; +} + void mptcp_space(const struct sock *ssk, int *space, int *full_space); bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, unsigned int *size, struct mptcp_out_options *opts); @@ -121,8 +126,6 @@ static inline bool mptcp_skb_can_collapse(const struct sk_buff *to, skb_ext_find(from, SKB_EXT_MPTCP)); } -bool mptcp_sk_is_subflow(const struct sock *sk); - void mptcp_seq_show(struct seq_file *seq); #else @@ -140,6 +143,11 @@ static inline bool rsk_is_mptcp(const struct request_sock *req) return false; } +static inline bool sk_drop_req(const struct sock *sk) +{ + return false; +} + static inline void mptcp_parse_option(const struct sk_buff *skb, const unsigned char *ptr, int opsize, struct tcp_options_received *opt_rx) @@ -190,11 +198,6 @@ static inline bool mptcp_skb_can_collapse(const struct sk_buff *to, return true; } -static inline bool mptcp_sk_is_subflow(const struct sock *sk) -{ - return false; -} - static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { } static inline void mptcp_seq_show(struct seq_file *seq) { } #endif /* CONFIG_MPTCP */ diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 7e40322cc5ec..ba7cfb22dc79 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -774,7 +774,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, if (!child) goto listen_overflow; - if (own_req && sk_is_mptcp(child) && mptcp_sk_is_subflow(child)) { + if (own_req && sk_drop_req(child)) { reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req); inet_csk_reqsk_queue_drop_and_put(sk, req); return child; diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index e1f23016ed3f..a61e60e94137 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1638,13 +1638,6 @@ bool mptcp_finish_join(struct sock *sk) return ret; } -bool mptcp_sk_is_subflow(const struct sock *sk) -{ - struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); - - return subflow->mp_join == 1; -} - static bool mptcp_memory_free(const struct sock *sk, int wake) { struct mptcp_sock *msk = mptcp_sk(sk); diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 009d5c478062..b39a66ffac7a 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -500,6 +500,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, ctx->remote_key = mp_opt.sndr_key; ctx->fully_established = mp_opt.mp_capable; ctx->can_ack = mp_opt.mp_capable; + tcp_sk(child)->drop_req = false; } else if (ctx->mp_join) { struct mptcp_sock *owner; @@ -512,6 +513,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, goto close_child; SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX); + tcp_sk(child)->drop_req = true; } }