Commit a88d0092 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: simplify subflow_syn_recv_sock() 

Postpone the msk cloning to the child process creation
so that we can avoid a bunch of conditionals.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/61


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2bb9a37f

net/mptcp/subflow.c

+13 −28
Original line number Diff line number Diff line
@@ -696,14 +696,6 @@ static bool subflow_hmac_valid(const struct request_sock *req, 
	return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);

}



static void mptcp_force_close(struct sock *sk)

{

	/* the msk is not yet exposed to user-space, and refcount is 2 */

	inet_sk_state_store(sk, TCP_CLOSE);

	sk_common_release(sk);

	sock_put(sk);

}



static void subflow_ulp_fallback(struct sock *sk,

				 struct mptcp_subflow_context *old_ctx)

{
@@ -755,7 +747,6 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
	struct mptcp_subflow_request_sock *subflow_req;

	struct mptcp_options_received mp_opt;

	bool fallback, fallback_is_fatal;

	struct sock *new_msk = NULL;

	struct mptcp_sock *owner;

	struct sock *child;
@@ -784,14 +775,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
		 * options.

		 */

		mptcp_get_options(skb, &mp_opt);

		if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) {

		if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC))

			fallback = true;

			goto create_child;

		}



		new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);

		if (!new_msk)

			fallback = true;

	} else if (subflow_req->mp_join) {

		mptcp_get_options(skb, &mp_opt);

		if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) ||
@@ -820,21 +806,23 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
				subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);

				goto dispose_child;

			}



			mptcp_subflow_drop_ctx(child);

			goto out;

			goto fallback;

		}



		/* ssk inherits options of listener sk */

		ctx->setsockopt_seq = listener->setsockopt_seq;



		if (ctx->mp_capable) {

			owner = mptcp_sk(new_msk);

			ctx->conn = mptcp_sk_clone(listener->conn, &mp_opt, req);

			if (!ctx->conn)

				goto fallback;



			owner = mptcp_sk(ctx->conn);



			/* this can't race with mptcp_close(), as the msk is

			 * not yet exposted to user-space

			 */

			inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);

			inet_sk_state_store(ctx->conn, TCP_ESTABLISHED);



			/* record the newly created socket as the first msk

			 * subflow, but don't link it yet into conn_list
@@ -844,11 +832,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
			/* new mpc subflow takes ownership of the newly

			 * created mptcp socket

			 */

			mptcp_sk(new_msk)->setsockopt_seq = ctx->setsockopt_seq;

			owner->setsockopt_seq = ctx->setsockopt_seq;

			mptcp_pm_new_connection(owner, child, 1);

			mptcp_token_accept(subflow_req, owner);

			ctx->conn = new_msk;

			new_msk = NULL;



			/* set msk addresses early to ensure mptcp_pm_get_local_id()

			 * uses the correct data
@@ -898,11 +884,6 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
		}

	}



out:

	/* dispose of the left over mptcp master, if any */

	if (unlikely(new_msk))

		mptcp_force_close(new_msk);



	/* check for expected invariant - should never trigger, just help

	 * catching eariler subtle bugs

	 */
@@ -920,6 +901,10 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 


	/* The last child reference will be released by the caller */

	return child;



fallback:

	mptcp_subflow_drop_ctx(child);

	return child;

}



static struct inet_connection_sock_af_ops subflow_specific __ro_after_init;