From patchwork Tue Apr 27 03:46:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Iwashima, Kuniyuki" X-Patchwork-Id: 12225301 X-Patchwork-Delegate: bpf@iogearbox.net 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 2BFF1C433ED for ; Tue, 27 Apr 2021 03:48:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE07A613B0 for ; Tue, 27 Apr 2021 03:48:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232618AbhD0Dsx (ORCPT ); Mon, 26 Apr 2021 23:48:53 -0400 Received: from smtp-fw-9103.amazon.com ([207.171.188.200]:33951 "EHLO smtp-fw-9103.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234406AbhD0Dsw (ORCPT ); Mon, 26 Apr 2021 23:48:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.co.jp; i=@amazon.co.jp; q=dns/txt; s=amazon201209; t=1619495290; x=1651031290; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=riz39euh9VJ0Ml0wQ4FZVlkKZ1mau/Z7qyONSzLLBF4=; b=qdX30aDurr6ECjFPPhN8Ega037iuJDzh5WIfhO3c9JSmpEDRYuTYZvVs SEbsss6sqxqcJcJsUPnGQcsW+iYILi0ZT5v0NOsEKkPtcuxq8xIuzDhai 3r0E8OPQkd7+R12+T/xypRv2gzUDh7sDUlWVMTqQI1F4U/tDFFg1edvWz Q=; X-IronPort-AV: E=Sophos;i="5.82,254,1613433600"; d="scan'208";a="929262106" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-2a-41350382.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-9103.sea19.amazon.com with ESMTP; 27 Apr 2021 03:48:10 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-2a-41350382.us-west-2.amazon.com (Postfix) with ESMTPS id 7A778C7643; Tue, 27 Apr 2021 03:48:09 +0000 (UTC) Received: from EX13D04ANC001.ant.amazon.com (10.43.157.89) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 27 Apr 2021 03:48:08 +0000 Received: from 88665a182662.ant.amazon.com (10.43.162.93) by EX13D04ANC001.ant.amazon.com (10.43.157.89) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 27 Apr 2021 03:47:57 +0000 From: Kuniyuki Iwashima To: "David S . Miller" , Jakub Kicinski , Eric Dumazet , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau CC: Benjamin Herrenschmidt , Kuniyuki Iwashima , Kuniyuki Iwashima , , , Subject: [PATCH v4 bpf-next 04/11] tcp: Add reuseport_migrate_sock() to select a new listener. Date: Tue, 27 Apr 2021 12:46:16 +0900 Message-ID: <20210427034623.46528-5-kuniyu@amazon.co.jp> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210427034623.46528-1-kuniyu@amazon.co.jp> References: <20210427034623.46528-1-kuniyu@amazon.co.jp> MIME-Version: 1.0 X-Originating-IP: [10.43.162.93] X-ClientProxiedBy: EX13D18UWC002.ant.amazon.com (10.43.162.88) To EX13D04ANC001.ant.amazon.com (10.43.157.89) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net reuseport_migrate_sock() does the same check done in reuseport_listen_stop_sock(). If the reuseport group is capable of migration, reuseport_migrate_sock() selects a new listener by the child socket hash and increments the listener's sk_refcnt beforehand. Thus, if we fail in the migration, we have to decrement it later. We will support migration by eBPF in the later commits. Signed-off-by: Kuniyuki Iwashima Signed-off-by: Martin KaFai Lau --- include/net/sock_reuseport.h | 3 ++ net/core/sock_reuseport.c | 78 +++++++++++++++++++++++++++++------- 2 files changed, 67 insertions(+), 14 deletions(-) diff --git a/include/net/sock_reuseport.h b/include/net/sock_reuseport.h index 1333d0cddfbc..473b0b0fa4ab 100644 --- a/include/net/sock_reuseport.h +++ b/include/net/sock_reuseport.h @@ -37,6 +37,9 @@ extern struct sock *reuseport_select_sock(struct sock *sk, u32 hash, struct sk_buff *skb, int hdr_len); +struct sock *reuseport_migrate_sock(struct sock *sk, + struct sock *migrating_sk, + struct sk_buff *skb); extern int reuseport_attach_prog(struct sock *sk, struct bpf_prog *prog); extern int reuseport_detach_prog(struct sock *sk); diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c index d5fb0ad12e87..a2bca39ec0e3 100644 --- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -44,7 +44,7 @@ static void __reuseport_add_sock(struct sock *sk, struct sock_reuseport *reuse) { reuse->socks[reuse->num_socks] = sk; - /* paired with smp_rmb() in reuseport_select_sock() */ + /* paired with smp_rmb() in reuseport_(select|migrate)_sock() */ smp_wmb(); reuse->num_socks++; } @@ -435,6 +435,23 @@ static struct sock *run_bpf_filter(struct sock_reuseport *reuse, u16 socks, return reuse->socks[index]; } +static struct sock *reuseport_select_sock_by_hash(struct sock_reuseport *reuse, + u32 hash, u16 num_socks) +{ + int i, j; + + i = j = reciprocal_scale(hash, num_socks); + while (reuse->socks[i]->sk_state == TCP_ESTABLISHED) { + i++; + if (i >= num_socks) + i = 0; + if (i == j) + return NULL; + } + + return reuse->socks[i]; +} + /** * reuseport_select_sock - Select a socket from an SO_REUSEPORT group. * @sk: First socket in the group. @@ -478,19 +495,8 @@ struct sock *reuseport_select_sock(struct sock *sk, select_by_hash: /* no bpf or invalid bpf result: fall back to hash usage */ - if (!sk2) { - int i, j; - - i = j = reciprocal_scale(hash, socks); - while (reuse->socks[i]->sk_state == TCP_ESTABLISHED) { - i++; - if (i >= socks) - i = 0; - if (i == j) - goto out; - } - sk2 = reuse->socks[i]; - } + if (!sk2) + sk2 = reuseport_select_sock_by_hash(reuse, hash, socks); } out: @@ -499,6 +505,50 @@ struct sock *reuseport_select_sock(struct sock *sk, } EXPORT_SYMBOL(reuseport_select_sock); +/** + * reuseport_migrate_sock - Select a socket from an SO_REUSEPORT group. + * @sk: close()ed or shutdown()ed socket in the group. + * @migrating_sk: ESTABLISHED/SYN_RECV full socket in the accept queue or + * NEW_SYN_RECV request socket during 3WHS. + * @skb: skb to run through BPF filter. + * Returns a socket (with sk_refcnt +1) that should accept the child socket + * (or NULL on error). + */ +struct sock *reuseport_migrate_sock(struct sock *sk, + struct sock *migrating_sk, + struct sk_buff *skb) +{ + struct sock_reuseport *reuse; + struct sock *nsk = NULL; + u16 socks; + u32 hash; + + rcu_read_lock(); + + reuse = rcu_dereference(sk->sk_reuseport_cb); + if (!reuse) + goto out; + + socks = READ_ONCE(reuse->num_socks); + if (unlikely(!socks)) + goto out; + + /* paired with smp_wmb() in __reuseport_add_sock() */ + smp_rmb(); + + hash = migrating_sk->sk_hash; + if (sock_net(sk)->ipv4.sysctl_tcp_migrate_req) + nsk = reuseport_select_sock_by_hash(reuse, hash, socks); + + if (nsk && unlikely(!refcount_inc_not_zero(&nsk->sk_refcnt))) + nsk = NULL; + +out: + rcu_read_unlock(); + return nsk; +} +EXPORT_SYMBOL(reuseport_migrate_sock); + int reuseport_attach_prog(struct sock *sk, struct bpf_prog *prog) { struct sock_reuseport *reuse;