Commit 4cf86ae8 authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: strict local address ID selection 



The address ID selection for MPJ subflows created in response
to incoming ADD_ADDR option is currently unreliable: it happens
at MPJ socket creation time, when the local address could be
unknown.

Additionally, if the no local endpoint is available for the local
address, a new dummy endpoint is created, confusing the user-land.

This change refactor the code to move the address ID selection inside
the rebuild_header() helper, when the local address eventually
selected by the route lookup is finally known. If the address used
is not mapped by any endpoint - and thus can't be advertised/removed
pick the id 0 instead of allocate a new endpoint.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d045b9eb

net/mptcp/pm_netlink.c

+0 −13
Original line number Diff line number Diff line
@@ -83,16 +83,6 @@ static bool addresses_equal(const struct mptcp_addr_info *a, 
	return a->port == b->port;

}



static bool address_zero(const struct mptcp_addr_info *addr)

{

	struct mptcp_addr_info zero;



	memset(&zero, 0, sizeof(zero));

	zero.family = addr->family;



	return addresses_equal(addr, &zero, true);

}



static void local_address(const struct sock_common *skc,

			  struct mptcp_addr_info *addr)

{
@@ -1039,9 +1029,6 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) 
	if (addresses_equal(&msk_local, &skc_local, false))

		return 0;



	if (address_zero(&skc_local))

		return 0;



	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);



	rcu_read_lock();

net/mptcp/protocol.c

+3 −0
Original line number Diff line number Diff line
@@ -117,6 +117,9 @@ static int __mptcp_socket_create(struct mptcp_sock *msk) 
	list_add(&subflow->node, &msk->conn_list);

	sock_hold(ssock->sk);

	subflow->request_mptcp = 1;



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

	subflow->local_id_valid = 1;

	mptcp_sock_graft(msk->first, sk->sk_socket);



	return 0;

net/mptcp/protocol.h

+2 −1
Original line number Diff line number Diff line
@@ -442,7 +442,8 @@ struct mptcp_subflow_context { 
		rx_eof : 1,

		can_ack : 1,        /* only after processing the remote a key */

		disposable : 1,	    /* ctx can be free at ulp release time */

		stale : 1;	    /* unable to snd/rcv data, do not use for xmit */

		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */

		local_id_valid : 1; /* local_id is correctly initialized */

	enum mptcp_data_avail data_avail;

	u32	remote_nonce;

	u64	thmac;

net/mptcp/subflow.c

+58 −9
Original line number Diff line number Diff line
@@ -481,6 +481,51 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) 
	mptcp_subflow_reset(sk);

}



static void subflow_set_local_id(struct mptcp_subflow_context *subflow, int local_id)

{

	subflow->local_id = local_id;

	subflow->local_id_valid = 1;

}



static int subflow_chk_local_id(struct sock *sk)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);

	struct mptcp_sock *msk = mptcp_sk(subflow->conn);

	int err;



	if (likely(subflow->local_id_valid))

		return 0;



	err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk);

	if (err < 0)

		return err;



	subflow_set_local_id(subflow, err);

	return 0;

}



static int subflow_rebuild_header(struct sock *sk)

{

	int err = subflow_chk_local_id(sk);



	if (unlikely(err < 0))

		return err;



	return inet_sk_rebuild_header(sk);

}



#if IS_ENABLED(CONFIG_MPTCP_IPV6)

static int subflow_v6_rebuild_header(struct sock *sk)

{

	int err = subflow_chk_local_id(sk);



	if (unlikely(err < 0))

		return err;



	return inet6_sk_rebuild_header(sk);

}

#endif



struct request_sock_ops mptcp_subflow_request_sock_ops;

static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init;
@@ -1398,13 +1443,8 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, 
		get_random_bytes(&subflow->local_nonce, sizeof(u32));

	} while (!subflow->local_nonce);



	if (!local_id) {

		err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk);

		if (err < 0)

			goto failed;



		local_id = err;

	}

	if (local_id)

		subflow_set_local_id(subflow, local_id);



	mptcp_pm_get_flags_and_ifindex_by_id(sock_net(sk), local_id,

					     &flags, &ifindex);
@@ -1429,7 +1469,6 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, 
	pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk,

		 remote_token, local_id, remote_id);

	subflow->remote_token = remote_token;

	subflow->local_id = local_id;

	subflow->remote_id = remote_id;

	subflow->request_join = 1;

	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
@@ -1728,15 +1767,22 @@ static void subflow_ulp_clone(const struct request_sock *req, 
		new_ctx->token = subflow_req->token;

		new_ctx->ssn_offset = subflow_req->ssn_offset;

		new_ctx->idsn = subflow_req->idsn;



		/* this is the first subflow, id is always 0 */

		new_ctx->local_id_valid = 1;

	} else if (subflow_req->mp_join) {

		new_ctx->ssn_offset = subflow_req->ssn_offset;

		new_ctx->mp_join = 1;

		new_ctx->fully_established = 1;

		new_ctx->backup = subflow_req->backup;

		new_ctx->local_id = subflow_req->local_id;

		new_ctx->remote_id = subflow_req->remote_id;

		new_ctx->token = subflow_req->token;

		new_ctx->thmac = subflow_req->thmac;



		/* the subflow req id is valid, fetched via subflow_check_req()

		 * and subflow_token_join_request()

		 */

		subflow_set_local_id(new_ctx, subflow_req->local_id);

	}

}
@@ -1789,6 +1835,7 @@ void __init mptcp_subflow_init(void) 
	subflow_specific.conn_request = subflow_v4_conn_request;

	subflow_specific.syn_recv_sock = subflow_syn_recv_sock;

	subflow_specific.sk_rx_dst_set = subflow_finish_connect;

	subflow_specific.rebuild_header = subflow_rebuild_header;



	tcp_prot_override = tcp_prot;

	tcp_prot_override.release_cb = tcp_release_cb_override;
@@ -1801,6 +1848,7 @@ void __init mptcp_subflow_init(void) 
	subflow_v6_specific.conn_request = subflow_v6_conn_request;

	subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock;

	subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect;

	subflow_v6_specific.rebuild_header = subflow_v6_rebuild_header;



	subflow_v6m_specific = subflow_v6_specific;

	subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit;
@@ -1808,6 +1856,7 @@ void __init mptcp_subflow_init(void) 
	subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len;

	subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced;

	subflow_v6m_specific.net_frag_header_len = 0;

	subflow_v6m_specific.rebuild_header = subflow_rebuild_header;



	tcpv6_prot_override = tcpv6_prot;

	tcpv6_prot_override.release_cb = tcp_release_cb_override;