Commit 6f06b4d4 authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: add subflow unique id 

The user-space need to properly account the data received/sent by
individual subflows. When additional subflows are created and/or
closed during the MPTCP socket lifetime, the information currently
exposed via MPTCP_TCPINFO are not enough: subflows are identified only
by the sequential position inside the info dumps, and that will change
with the above mentioned events.

To solve the above problem, this patch introduces a new subflow
identifier that is unique inside the given MPTCP socket scope.

The initial subflow get the id 1 and the other subflows get incremental
values at join time.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/388


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 avatarJakub Kicinski <kuba@kernel.org>
parent 5dcff89e

net/mptcp/protocol.c

+6 −0
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ static int __mptcp_socket_create(struct mptcp_sock *msk) 
	list_add(&subflow->node, &msk->conn_list);

	sock_hold(ssock->sk);

	subflow->request_mptcp = 1;

	subflow->subflow_id = msk->subflow_id++;



	/* This is the first subflow, always with id 0 */

	subflow->local_id_valid = 1;
@@ -847,6 +848,7 @@ static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) 
	if (sk->sk_socket && !ssk->sk_socket)

		mptcp_sock_graft(ssk, sk->sk_socket);



	mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;

	mptcp_sockopt_sync_locked(msk, ssk);

	mptcp_subflow_joined(msk, ssk);

	return true;
@@ -2732,6 +2734,7 @@ static int __mptcp_init_sock(struct sock *sk) 
	WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));

	WRITE_ONCE(msk->allow_infinite_fallback, true);

	msk->recovery = false;

	msk->subflow_id = 1;



	mptcp_pm_data_init(msk);
@@ -3160,6 +3163,9 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk, 
	msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;

	msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;



	/* passive msk is created after the first/MPC subflow */

	msk->subflow_id = 2;



	sock_reset_flag(nsk, SOCK_RCU_FREE);

	security_inet_csk_clone(nsk, req);

net/mptcp/protocol.h

+4 −1
Original line number Diff line number Diff line
@@ -323,6 +323,7 @@ struct mptcp_sock { 
		u64	rtt_us; /* last maximum rtt of subflows */

	} rcvq_space;



	u32		subflow_id;

	u32		setsockopt_seq;

	char		ca_name[TCP_CA_NAME_MAX];

	struct mptcp_sock	*dl_next;
@@ -504,6 +505,8 @@ struct mptcp_subflow_context { 
	u8	reset_reason:4;

	u8	stale_count;



	u32	subflow_id;



	long	delegated_status;

	unsigned long	fail_tout;

net/mptcp/subflow.c

+2 −0
Original line number Diff line number Diff line
@@ -819,6 +819,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
			if (!ctx->conn)

				goto fallback;



			ctx->subflow_id = 1;

			owner = mptcp_sk(ctx->conn);

			mptcp_pm_new_connection(owner, child, 1);
@@ -1574,6 +1575,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, 
	subflow->remote_id = remote_id;

	subflow->request_join = 1;

	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);

	subflow->subflow_id = msk->subflow_id++;

	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);



	sock_hold(ssk);