From patchwork Tue Dec 19 21:31:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthieu Baerts X-Patchwork-Id: 756272 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B6A343C6A6; Tue, 19 Dec 2023 21:38:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HuDvY7y+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4271EC433CB; Tue, 19 Dec 2023 21:38:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1703021901; bh=8Zn/iQVfoK4WIL45SvwHhkDsI7IJQsZYNrWnNX4iYfk=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=HuDvY7y+npE2BYFAUTGUmPTqoqv1kQMFubqpoOMTHEw94/UgqfarMZzqIiU292UCR oTwpXDOt1LH+RBBpPCu1RGziPoGXjlBTH3BCDP1Jhxst0EE58gKfPwljzajMSC7eV0 MjM3FCS8WxleAUTw3W/ttmaeCDWe5lXkWt9B70wbCscQ/c34zvHC+Gv9ZV4a5uH3Qp esBH+U6iYGdlWkdNPrxus/UvWPjqL6R+3kRgYoyxc9/mM3LKsNl/cn2FG6S++8yqSA 7m2TAmhODtgAxL3wJ4yyeRV2YpPbzi87RKfd7sV7nqpLCyhhVZBedXlmUEsSaOMo7X Z6Hzp7bdMGGGA== From: Matthieu Baerts Date: Tue, 19 Dec 2023 22:31:04 +0100 Subject: [PATCH net-next 1/4] mptcp: don't overwrite sock_ops in mptcp_is_tcpsk() Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231219-upstream-net-next-20231219-mptcp-sockopts-ephemeral-ports-v1-1-2b13bedfcaf8@kernel.org> References: <20231219-upstream-net-next-20231219-mptcp-sockopts-ephemeral-ports-v1-0-2b13bedfcaf8@kernel.org> In-Reply-To: <20231219-upstream-net-next-20231219-mptcp-sockopts-ephemeral-ports-v1-0-2b13bedfcaf8@kernel.org> To: mptcp@lists.linux.dev, Mat Martineau , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Shuah Khan Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Matthieu Baerts , Davide Caratti X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=openpgp-sha256; l=5762; i=matttbe@kernel.org; h=from:subject:message-id; bh=v4M3WEJtEY7LyvLuXHxK426HlsZ0UnL0hBK4mmkBBmM=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBlgg1GSxhyd+Jy3SU8214jmetGhy6hxnoL0WzJj F0ZIO/6uleJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZYINRgAKCRD2t4JPQmmg c4eqEAC5G8QY+40kuyodpRXOK2hthefXhY9PWnUYLMK3OWk0kSxOo6+Yq1WiEOGKFgBmNKzjX/m a214ydCa+XPU8Gb61k6UoJdNUQzjxdMIB4NJVHgQuvHxK5IM1wSqdlegxfel+6zyKN5yKjiUjs8 AT8uijfxfKekhF5OoM0qoZ2ddLh3sWw4EyEiqvVReBcpdlZlzSLIXXcm4fsnkTaBj7paPujid39 RgmZ+9R1189GME94H4E8rLb/HFkLBVc9N7X7EMXPC59TAG03psJi0biEuXhMwtbfBagMPyS9t2k GfvkFccygiuR4V3DOVXsyEMyQW5No/VFVEsGvnz0vuUrhawUxzx8vSiI7dLv0K2gqC2GKtct0mC 8wqeKYt6Sih7PhM+FhFYwDnpzDekAjVYuOjsF4qfFcYeY4K3k96J4xB8BKvNessUljRKfwA16zD kNGdRMvAjhFj+9amHHHrqujggIRFUhTiKD//xBqZ4/VUIQ4uiBs7XSA5NnUqPA36q85NmQjIWGA aDbXAdIxhj5BXSQAKtbIBEk0OGqMwyJNV4pp8HrixqJbmx6QObj4xBrg3BwohjiKMyyn+ZwT5A1 cw4BCHZlTBBHj2WG95mXgxdy8S1bhjjJm7SbriqRVn4jdVBk31YFa9OCy9d/wFF6usHpvvwvjaN uAXWkYP9KQEU4lg== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Davide Caratti Eric Dumazet suggests: > The fact that mptcp_is_tcpsk() was able to write over sock->ops was a > bit strange to me. > mptcp_is_tcpsk() should answer a question, with a read-only argument. re-factor code to avoid overwriting sock_ops inside that function. Also, change the helper name to reflect the semantics and to disambiguate from its dual, sk_is_mptcp(). While at it, collapse mptcp_stream_accept() and mptcp_accept() into a single function, where fallback / non-fallback are separated into a single sk_is_mptcp() conditional. Link: https://github.com/multipath-tcp/mptcp_net-next/issues/432 Suggested-by: Eric Dumazet Signed-off-by: Davide Caratti Acked-by: Paolo Abeni Signed-off-by: Matthieu Baerts --- net/mptcp/protocol.c | 108 +++++++++++++++++++++------------------------------ 1 file changed, 44 insertions(+), 64 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index bc81ea53a049..5cbbd1221030 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -55,28 +55,14 @@ static u64 mptcp_wnd_end(const struct mptcp_sock *msk) return READ_ONCE(msk->wnd_end); } -static bool mptcp_is_tcpsk(struct sock *sk) +static const struct proto_ops *mptcp_fallback_tcp_ops(const struct sock *sk) { - struct socket *sock = sk->sk_socket; - - if (unlikely(sk->sk_prot == &tcp_prot)) { - /* we are being invoked after mptcp_accept() has - * accepted a non-mp-capable flow: sk is a tcp_sk, - * not an mptcp one. - * - * Hand the socket over to tcp so all further socket ops - * bypass mptcp. - */ - WRITE_ONCE(sock->ops, &inet_stream_ops); - return true; #if IS_ENABLED(CONFIG_MPTCP_IPV6) - } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { - WRITE_ONCE(sock->ops, &inet6_stream_ops); - return true; + if (sk->sk_prot == &tcpv6_prot) + return &inet6_stream_ops; #endif - } - - return false; + WARN_ON_ONCE(sk->sk_prot != &tcp_prot); + return &inet_stream_ops; } static int __mptcp_socket_create(struct mptcp_sock *msk) @@ -3258,44 +3244,6 @@ void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); } -static struct sock *mptcp_accept(struct sock *ssk, int flags, int *err, - bool kern) -{ - struct sock *newsk; - - pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk)); - newsk = inet_csk_accept(ssk, flags, err, kern); - if (!newsk) - return NULL; - - pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk)); - if (sk_is_mptcp(newsk)) { - struct mptcp_subflow_context *subflow; - struct sock *new_mptcp_sock; - - subflow = mptcp_subflow_ctx(newsk); - new_mptcp_sock = subflow->conn; - - /* is_mptcp should be false if subflow->conn is missing, see - * subflow_syn_recv_sock() - */ - if (WARN_ON_ONCE(!new_mptcp_sock)) { - tcp_sk(newsk)->is_mptcp = 0; - goto out; - } - - newsk = new_mptcp_sock; - MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK); - } else { - MPTCP_INC_STATS(sock_net(ssk), - MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); - } - -out: - newsk->sk_kern_sock = kern; - return newsk; -} - void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) { struct mptcp_subflow_context *subflow, *tmp; @@ -3739,7 +3687,6 @@ static struct proto mptcp_prot = { .connect = mptcp_connect, .disconnect = mptcp_disconnect, .close = mptcp_close, - .accept = mptcp_accept, .setsockopt = mptcp_setsockopt, .getsockopt = mptcp_getsockopt, .shutdown = mptcp_shutdown, @@ -3849,18 +3796,36 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, if (!ssk) return -EINVAL; - newsk = mptcp_accept(ssk, flags, &err, kern); + pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk)); + newsk = inet_csk_accept(ssk, flags, &err, kern); if (!newsk) return err; - lock_sock(newsk); - - __inet_accept(sock, newsock, newsk); - if (!mptcp_is_tcpsk(newsock->sk)) { - struct mptcp_sock *msk = mptcp_sk(newsk); + pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk)); + if (sk_is_mptcp(newsk)) { struct mptcp_subflow_context *subflow; + struct sock *new_mptcp_sock; + + subflow = mptcp_subflow_ctx(newsk); + new_mptcp_sock = subflow->conn; + + /* is_mptcp should be false if subflow->conn is missing, see + * subflow_syn_recv_sock() + */ + if (WARN_ON_ONCE(!new_mptcp_sock)) { + tcp_sk(newsk)->is_mptcp = 0; + goto tcpfallback; + } + + newsk = new_mptcp_sock; + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK); + + newsk->sk_kern_sock = kern; + lock_sock(newsk); + __inet_accept(sock, newsock, newsk); set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags); + msk = mptcp_sk(newsk); msk->in_accept_queue = 0; /* set ssk->sk_socket of accept()ed flows to mptcp socket. @@ -3882,6 +3847,21 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, if (unlikely(list_is_singular(&msk->conn_list))) inet_sk_state_store(newsk, TCP_CLOSE); } + } else { + MPTCP_INC_STATS(sock_net(ssk), + MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); +tcpfallback: + newsk->sk_kern_sock = kern; + lock_sock(newsk); + __inet_accept(sock, newsock, newsk); + /* we are being invoked after accepting a non-mp-capable + * flow: sk is a tcp_sk, not an mptcp one. + * + * Hand the socket over to tcp so all further socket ops + * bypass mptcp. + */ + WRITE_ONCE(newsock->sk->sk_socket->ops, + mptcp_fallback_tcp_ops(newsock->sk)); } release_sock(newsk);