Commit 263e1201 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: consolidate synack processing. 



Currently the MPTCP code uses 2 hooks to process syn-ack
packets, mptcp_rcv_synsent() and the sk_rx_dst_set()
callback.

We can drop the first, moving the relevant code into the
latter, reducing the hooking into the TCP code. This is
also needed by the next patch.

v1 -> v2:
 - use local tcp sock ptr instead of casting the sk variable
   several times - DaveM

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 30724ccb

include/net/mptcp.h

+0 −1
Original line number Diff line number Diff line
@@ -72,7 +72,6 @@ void mptcp_parse_option(const struct sk_buff *skb, const unsigned char *ptr, 
			int opsize, struct tcp_options_received *opt_rx);

bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,

		       unsigned int *size, struct mptcp_out_options *opts);

void mptcp_rcv_synsent(struct sock *sk);

bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,

			  struct mptcp_out_options *opts);

bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,

net/ipv4/tcp_input.c

+0 −3
Original line number Diff line number Diff line
@@ -5990,9 +5990,6 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, 
		tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);

		tcp_initialize_rcv_mss(sk);



		if (sk_is_mptcp(sk))

			mptcp_rcv_synsent(sk);



		/* Remember, tcp_poll() does not lock socket!

		 * Change state from SYN-SENT only after copied_seq

		 * is initialized. */

net/mptcp/options.c

+0 −22
Original line number Diff line number Diff line
@@ -344,28 +344,6 @@ bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, 
	return false;

}



void mptcp_rcv_synsent(struct sock *sk)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);

	struct tcp_sock *tp = tcp_sk(sk);



	if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) {

		subflow->mp_capable = 1;

		subflow->can_ack = 1;

		subflow->remote_key = tp->rx_opt.mptcp.sndr_key;

		pr_debug("subflow=%p, remote_key=%llu", subflow,

			 subflow->remote_key);

	} else if (subflow->request_join && tp->rx_opt.mptcp.mp_join) {

		subflow->mp_join = 1;

		subflow->thmac = tp->rx_opt.mptcp.thmac;

		subflow->remote_nonce = tp->rx_opt.mptcp.nonce;

		pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,

			 subflow->thmac, subflow->remote_nonce);

	} else if (subflow->request_mptcp) {

		tcp_sk(sk)->is_mptcp = 0;

	}

}



/* MP_JOIN client subflow must wait for 4th ack before sending any data:

 * TCP can't schedule delack timer before the subflow is fully established.

 * MPTCP uses the delack timer to do 3rd ack retransmissions

net/mptcp/subflow.c

+24 −3
Original line number Diff line number Diff line
@@ -222,6 +222,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) 
{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);

	struct sock *parent = subflow->conn;

	struct tcp_sock *tp = tcp_sk(sk);



	subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
@@ -230,14 +231,35 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) 
		parent->sk_state_change(parent);

	}



	if (subflow->conn_finished || !tcp_sk(sk)->is_mptcp)

	/* be sure no special action on any packet other than syn-ack */

	if (subflow->conn_finished)

		return;



	subflow->conn_finished = 1;



	if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) {

		subflow->mp_capable = 1;

		subflow->can_ack = 1;

		subflow->remote_key = tp->rx_opt.mptcp.sndr_key;

		pr_debug("subflow=%p, remote_key=%llu", subflow,

			 subflow->remote_key);

	} else if (subflow->request_join && tp->rx_opt.mptcp.mp_join) {

		subflow->mp_join = 1;

		subflow->thmac = tp->rx_opt.mptcp.thmac;

		subflow->remote_nonce = tp->rx_opt.mptcp.nonce;

		pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,

			 subflow->thmac, subflow->remote_nonce);

	} else if (subflow->request_mptcp) {

		tp->is_mptcp = 0;

	}



	if (!tp->is_mptcp)

		return;



	if (subflow->mp_capable) {

		pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),

			 subflow->remote_key);

		mptcp_finish_connect(sk);

		subflow->conn_finished = 1;



		if (skb) {

			pr_debug("synack seq=%u", TCP_SKB_CB(skb)->seq);
@@ -264,7 +286,6 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) 
		if (!mptcp_finish_join(sk))

			goto do_reset;



		subflow->conn_finished = 1;

		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);

	} else {

do_reset:

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