From nobody Thu Apr 2 14:43:02 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B962C07E9D for ; Fri, 23 Sep 2022 20:17:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232855AbiIWURy (ORCPT ); Fri, 23 Sep 2022 16:17:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232827AbiIWUPp (ORCPT ); Fri, 23 Sep 2022 16:15:45 -0400 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA85D124752 for ; Fri, 23 Sep 2022 13:14:14 -0700 (PDT) Received: by mail-wr1-x42f.google.com with SMTP id n10so1511204wrw.12 for ; Fri, 23 Sep 2022 13:14:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=QSlxelZmZQkauh748b/7aNwlVR4EaKtqFDpMBsT7q2s=; b=U6NipO/WIQWxS/+Jj3d/rVPxFAUKikH5/3i+w/aOIgkOpIBtgKhtkrV3ClKF7MyDGa MxEWLc2NhU4QPjlJxtZO4qziF0EFHJLKqGcuAzHAfyYYazgxLCJIm1oq3ee9oLKqcM1E 1d1fBFIMAtmLQYGJwlus2jofkrfEGouUvI0g8hAWL4ojN1v6JxLErDYCoHPX030i48FA B3pgPR6DYKK4dkwNqmAhsrFnrGQY5jsR+LVEwwDiCD3CS7JEZ/DoXuk8Y1L24RspQR1e +HTd+azien7FwppHeI+V/vzKOt7oV8kZHmVgHSaqqbFPSnLx6+XfWG/fBXnF4Wn1rkIy FDFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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; bh=QSlxelZmZQkauh748b/7aNwlVR4EaKtqFDpMBsT7q2s=; b=7AiEl236Dd9NJqC8pFTYZxsat82577CLj/VGAQaVewDPHOVT+Jud0t+kl5lCoPNhDq ueTTFcfnYnmN3wQ546hRQQKE4n35GRMh0as/ggWkg5mNZIhUkT2mBANTa4owLRtl/79l 21YUNiYQl7z4iF/I5FP+CHhQNOnM3/+1+Yip+qdV1wGDsIdPCKuwRzuCcP3MOpJBiAr+ J98Qn0cC5n7TAwsTIjSqdOgUcBtI+A7JtcikfhbZ4eBlOfYUw0ZRz6eo224L1h6AZpRz aDlDJNr1Rzgyw2ESheew5IaLFjqLLWYMPqb2WSdxY47fRdm4ccNO39eegHJCacI7Q1Jo N43A== X-Gm-Message-State: ACrzQf3/gExP+RhNaPGKusYPBk71bXSC3s/P1jXOn9mLbcUt15YZhymn 6TnuZv9lphsWxnmEmdIAF4jGQCNt7c0rgQ== X-Google-Smtp-Source: AMsMyM4Mco6j50zScn0pA1uSr0W0RCMLK0MagZMF94m1Efp9WHSd2cOmkVjbX1l1RMC/fTgjGZzsJw== X-Received: by 2002:a5d:6808:0:b0:22a:c437:5b36 with SMTP id w8-20020a5d6808000000b0022ac4375b36mr6285460wru.459.1663964044375; Fri, 23 Sep 2022 13:14:04 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id k11-20020a05600c0b4b00b003b492753826sm3281056wmr.43.2022.09.23.13.14.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Sep 2022 13:14:03 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet Cc: Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , Dan Carpenter , "David S. Miller" , Dmitry Safonov <0x7f454c46@gmail.com>, Eric Biggers , "Eric W. Biederman" , Francesco Ruggeri , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Jakub Kicinski , Leonard Crestez , Paolo Abeni , Salam Noureddine , Shuah Khan , netdev@vger.kernel.org, linux-crypto@vger.kernel.org Subject: [PATCH v2 24/35] net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs) Date: Fri, 23 Sep 2022 21:13:08 +0100 Message-Id: <20220923201319.493208-25-dima@arista.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220923201319.493208-1-dima@arista.com> References: <20220923201319.493208-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Delete becomes very, very fast - almost free, but after setsockopt() syscall returns, the key is still alive until next RCU grace period. Which is fine for listen sockets as userspace needs to be aware of setsockopt(TCP_AO) and accept() race and resolve it with verification by getsockopt() after TCP connection was accepted. The benchmark results (on non-loaded box, worse with more RCU work pending): > ok 33 Worst case delete 16384 keys: min=3D5ms max=3D10ms mean=3D6.9= 3904ms stddev=3D0.263421 > ok 34 Add a new key 16384 keys: min=3D1ms max=3D4ms mean=3D2.17= 751ms stddev=3D0.147564 > ok 35 Remove random-search 16384 keys: min=3D5ms max=3D10ms mean=3D6.5= 0243ms stddev=3D0.254999 > ok 36 Remove async 16384 keys: min=3D0ms max=3D0ms mean=3D0.02= 96107ms stddev=3D0.0172078 Co-developed-by: Francesco Ruggeri Signed-off-by: Francesco Ruggeri Co-developed-by: Salam Noureddine Signed-off-by: Salam Noureddine Signed-off-by: Dmitry Safonov --- include/uapi/linux/tcp.h | 3 +++ net/ipv4/tcp_ao.c | 17 ++++++++++++++++- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 453187d21da8..42850ae6e99d 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -353,6 +353,9 @@ struct tcp_diag_md5sig { #define TCP_AO_CMDF_CURR (1 << 0) /* Only checks field sndid */ #define TCP_AO_CMDF_NEXT (1 << 1) /* Only checks field rcvid */ #define TCP_AO_CMDF_ACCEPT_ICMP (1 << 2) /* Accept incoming ICMPs */ +#define TCP_AO_CMDF_DEL_ASYNC (1 << 3) /* Asynchronious delete, valid + * only for listen sockets + */ =20 #define TCP_AO_GET_CURR TCP_AO_CMDF_CURR #define TCP_AO_GET_NEXT TCP_AO_CMDF_NEXT diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 8f569f43e9c2..ed8cacb61694 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -1461,7 +1461,7 @@ static inline bool tcp_ao_mkt_overlap_v6(struct tcp_a= o *cmd, #define TCP_AO_CMDF_ADDMOD_VALID \ (TCP_AO_CMDF_CURR | TCP_AO_CMDF_NEXT | TCP_AO_CMDF_ACCEPT_ICMP) #define TCP_AO_CMDF_DEL_VALID \ - (TCP_AO_CMDF_CURR | TCP_AO_CMDF_NEXT) + (TCP_AO_CMDF_CURR | TCP_AO_CMDF_NEXT | TCP_AO_CMDF_DEL_ASYNC) #define TCP_AO_GETF_VALID \ (TCP_AO_GET_ALL | TCP_AO_GET_CURR | TCP_AO_GET_NEXT) =20 @@ -1586,11 +1586,26 @@ static int tcp_ao_delete_key(struct sock *sk, struc= t tcp_ao_key *key, =20 hlist_del_rcu(&key->node); =20 + /* Support for async delete on listening sockets: as they don't + * need current_key/rnext_key maintaining, we don't need to check + * them and we can just free all resources in RCU fashion. + */ + if (cmd->tcpa_flags & TCP_AO_CMDF_DEL_ASYNC) { + if (sk->sk_state !=3D TCP_LISTEN) + return -EINVAL; + atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); + call_rcu(&key->rcu, tcp_ao_key_free_rcu); + return 0; + } + /* At this moment another CPU could have looked this key up * while it was unlinked from the list. Wait for RCU grace period, * after which the key is off-list and can't be looked up again; * the rx path [just before RCU came] might have used it and set it * as current_key (very unlikely). + * Free the key with next RCU grace period (in case it was + * current_key before tcp_ao_current_rnext() might have + * changed it in forced-delete). */ synchronize_rcu(); err =3D tcp_ao_current_rnext(sk, cmd->tcpa_flags, --=20 2.37.2