From patchwork Thu Feb 17 14:25:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 12750268 X-Patchwork-Delegate: mat@martineau.name Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [193.142.43.52]) (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 C368A291C for ; Thu, 17 Feb 2022 14:25:57 +0000 (UTC) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1nKhjI-0004Ds-3j; Thu, 17 Feb 2022 15:25:56 +0100 From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH mptcp-next v2 3/5] tcp: add mptcp join demultiplex hooks Date: Thu, 17 Feb 2022 15:25:36 +0100 Message-Id: <20220217142538.7849-4-fw@strlen.de> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220217142538.7849-1-fw@strlen.de> References: <20220217142538.7849-1-fw@strlen.de> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Split from the next patch to make core tcp changes more obvious: add a dummy function that gets called after tcp socket demux came up empty. This will be used by mptcp to check if a tcp syn contains an mptcp join option with a valid token (connection id). If so, a hidden pernet mptcp listener socket is returned and packet resumes normally. This patch series does not cover timewait sockets so far. Signed-off-by: Florian Westphal --- include/net/mptcp.h | 5 +++++ net/ipv4/tcp_ipv4.c | 4 ++++ net/ipv6/tcp_ipv6.c | 4 ++++ 3 files changed, 13 insertions(+) diff --git a/include/net/mptcp.h b/include/net/mptcp.h index 8b1afd6f5cc4..5ee422b56902 100644 --- a/include/net/mptcp.h +++ b/include/net/mptcp.h @@ -197,6 +197,10 @@ static inline __be32 mptcp_reset_option(const struct sk_buff *skb) return htonl(0u); } +static inline struct sock *mptcp_handle_join(int af, struct sk_buff *skb) +{ + return NULL; +} #else static inline void mptcp_init(void) @@ -274,6 +278,7 @@ static inline int mptcp_subflow_init_cookie_req(struct request_sock *req, } static inline __be32 mptcp_reset_option(const struct sk_buff *skb) { return htonl(0u); } +static inline struct sock *mptcp_handle_join(int af, struct sk_buff *skb) { return NULL; } #endif /* CONFIG_MPTCP */ #if IS_ENABLED(CONFIG_MPTCP_IPV6) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6873f46fc8ba..6e6675a09443 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2140,6 +2140,10 @@ int tcp_v4_rcv(struct sk_buff *skb) if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) goto discard_it; + sk = mptcp_handle_join(AF_INET, skb); + if (sk) + goto process; + tcp_v4_fill_cb(skb, iph, th); if (tcp_checksum_complete(skb)) { diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 0c648bf07f39..788040db8e9e 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1782,6 +1782,10 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) goto discard_it; + sk = mptcp_handle_join(AF_INET6, skb); + if (sk) + goto process; + tcp_v6_fill_cb(skb, hdr, th); if (tcp_checksum_complete(skb)) {