From patchwork Wed Feb 23 11:08:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 12756761 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 61B22A57 for ; Wed, 23 Feb 2022 11:08:49 +0000 (UTC) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1nMpVn-0005hz-9S; Wed, 23 Feb 2022 12:08:47 +0100 From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH 2/4] tcp: add mptcp join demultiplex hooks Date: Wed, 23 Feb 2022 12:08:30 +0100 Message-Id: <20220223110832.29357-3-fw@strlen.de> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220223110832.29357-1-fw@strlen.de> References: <20220223110832.29357-1-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. Signed-off-by: Florian Westphal --- include/net/mptcp.h | 5 +++++ net/ipv4/tcp_ipv4.c | 7 +++++++ net/ipv6/tcp_ipv6.c | 7 +++++++ 3 files changed, 19 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 d42824aedc36..06e5bdf53278 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2155,6 +2155,10 @@ 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)) { @@ -2201,6 +2205,9 @@ int tcp_v4_rcv(struct sk_buff *skb) iph->daddr, th->dest, inet_iif(skb), sdif); + if (!sk2) + sk2 = mptcp_handle_join(AF_INET, skb); + if (sk2) { inet_twsk_deschedule_put(inet_twsk(sk)); sk = sk2; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 749de8529c83..8ae0db599f56 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1800,6 +1800,10 @@ 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)) { @@ -1849,6 +1853,9 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) ntohs(th->dest), tcp_v6_iif_l3_slave(skb), sdif); + if (!sk2) + sk2 = mptcp_handle_join(AF_INET6, skb); + if (sk2) { struct inet_timewait_sock *tw = inet_twsk(sk); inet_twsk_deschedule_put(tw);