Commit 86e39e04 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: keep track of local endpoint still available for each msk 



Include into the path manager status a bitmap tracking the list
of local endpoints still available - not yet used - for the
relevant mptcp socket.

Keep such map updated at endpoint creation/deletion time, so
that we can easily skip already used endpoint at local address
selection time.

The endpoint used by the initial subflow is lazyly accounted at
subflow creation time: the usage bitmap is be up2date before
endpoint selection and we avoid such unneeded task in some relevant
scenarios - e.g. busy servers accepting incoming subflows but
not creating any additional ones nor annuncing additional addresses.

Overall this allows for fair local endpoints usage in case of
subflow failure.

As a side effect, this patch also enforces that each endpoint
is used at most once for each mptcp connection.

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 avatarDavid S. Miller <davem@davemloft.net>
parent 71b077e4

net/mptcp/pm.c

+1 −0
Original line number Diff line number Diff line
@@ -370,6 +370,7 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk) 
	WRITE_ONCE(msk->pm.accept_subflow, false);

	WRITE_ONCE(msk->pm.remote_deny_join_id0, false);

	msk->pm.status = 0;

	bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);



	mptcp_pm_nl_data_init(msk);

}

net/mptcp/pm_netlink.c

+74 −51
Original line number Diff line number Diff line
@@ -38,10 +38,6 @@ struct mptcp_pm_add_entry { 
	u8			retrans_times;

};



/* max value of mptcp_addr_info.id */

#define MAX_ADDR_ID		U8_MAX

#define BITMAP_SZ DIV_ROUND_UP(MAX_ADDR_ID + 1, BITS_PER_LONG)



struct pm_nl_pernet {

	/* protects pernet updates */

	spinlock_t		lock;
@@ -53,14 +49,14 @@ struct pm_nl_pernet { 
	unsigned int		local_addr_max;

	unsigned int		subflows_max;

	unsigned int		next_id;

	unsigned long		id_bitmap[BITMAP_SZ];

	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);

};



#define MPTCP_PM_ADDR_MAX	8

#define ADD_ADDR_RETRANS_MAX	3



static bool addresses_equal(const struct mptcp_addr_info *a,

			    struct mptcp_addr_info *b, bool use_port)

			    const struct mptcp_addr_info *b, bool use_port)

{

	bool addr_equals = false;
@@ -174,6 +170,9 @@ select_local_address(const struct pm_nl_pernet *pernet, 
		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))

			continue;



		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))

			continue;



		if (entry->addr.family != sk->sk_family) {

#if IS_ENABLED(CONFIG_MPTCP_IPV6)

			if ((entry->addr.family == AF_INET &&
@@ -184,23 +183,17 @@ select_local_address(const struct pm_nl_pernet *pernet, 
				continue;

		}



		/* avoid any address already in use by subflows and

		 * pending join

		 */

		if (!lookup_subflow_by_saddr(&msk->conn_list, &entry->addr)) {

		ret = entry;

		break;

	}

	}

	rcu_read_unlock();

	return ret;

}



static struct mptcp_pm_addr_entry *

select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos)

select_signal_address(struct pm_nl_pernet *pernet, struct mptcp_sock *msk)

{

	struct mptcp_pm_addr_entry *entry, *ret = NULL;

	int i = 0;



	rcu_read_lock();

	/* do not keep any additional per socket state, just signal
@@ -209,13 +202,15 @@ select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos) 
	 * can lead to additional addresses not being announced.

	 */

	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {

		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))

			continue;



		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))

			continue;

		if (i++ == pos) {



		ret = entry;

		break;

	}

	}

	rcu_read_unlock();

	return ret;

}
@@ -258,9 +253,11 @@ EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max); 


static void check_work_pending(struct mptcp_sock *msk)

{

	if (msk->pm.add_addr_signaled == mptcp_pm_get_add_addr_signal_max(msk) &&

	    (msk->pm.local_addr_used == mptcp_pm_get_local_addr_max(msk) ||

	     msk->pm.subflows == mptcp_pm_get_subflows_max(msk)))

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



	if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||

	    (find_next_and_bit(pernet->id_bitmap, msk->pm.id_avail_bitmap,

			       MPTCP_PM_MAX_ADDR_ID + 1, 0) == MPTCP_PM_MAX_ADDR_ID + 1))

		WRITE_ONCE(msk->pm.work_pending, false);

}
@@ -460,6 +457,35 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullm 
	return i;

}



static struct mptcp_pm_addr_entry *

__lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)

{

	struct mptcp_pm_addr_entry *entry;



	list_for_each_entry(entry, &pernet->local_addr_list, list) {

		if (entry->addr.id == id)

			return entry;

	}

	return NULL;

}



static int

lookup_id_by_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr)

{

	struct mptcp_pm_addr_entry *entry;

	int ret = -1;



	rcu_read_lock();

	list_for_each_entry(entry, &pernet->local_addr_list, list) {

		if (addresses_equal(&entry->addr, addr, entry->addr.port)) {

			ret = entry->addr.id;

			break;

		}

	}

	rcu_read_unlock();

	return ret;

}



static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)

{

	struct sock *sk = (struct sock *)msk;
@@ -475,6 +501,19 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) 
	local_addr_max = mptcp_pm_get_local_addr_max(msk);

	subflows_max = mptcp_pm_get_subflows_max(msk);



	/* do lazy endpoint usage accounting for the MPC subflows */

	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {

		struct mptcp_addr_info local;

		int mpc_id;



		local_address((struct sock_common *)msk->first, &local);

		mpc_id = lookup_id_by_addr(pernet, &local);

		if (mpc_id < 0)

			__clear_bit(mpc_id, msk->pm.id_avail_bitmap);



		msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);

	}



	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",

		 msk->pm.local_addr_used, local_addr_max,

		 msk->pm.add_addr_signaled, add_addr_signal_max,
@@ -482,21 +521,16 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) 


	/* check first for announce */

	if (msk->pm.add_addr_signaled < add_addr_signal_max) {

		local = select_signal_address(pernet,

					      msk->pm.add_addr_signaled);

		local = select_signal_address(pernet, msk);



		if (local) {

			if (mptcp_pm_alloc_anno_list(msk, local)) {

				__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);

				msk->pm.add_addr_signaled++;

				mptcp_pm_announce_addr(msk, &local->addr, false);

				mptcp_pm_nl_addr_send_ack(msk);

			}

		} else {

			/* pick failed, avoid fourther attempts later */

			msk->pm.local_addr_used = add_addr_signal_max;

		}



		check_work_pending(msk);

	}



	/* check if should create a new subflow */
@@ -510,19 +544,16 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) 
			int i, nr;



			msk->pm.local_addr_used++;

			check_work_pending(msk);

			nr = fill_remote_addresses_vec(msk, fullmesh, addrs);

			if (nr)

				__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);

			spin_unlock_bh(&msk->pm.lock);

			for (i = 0; i < nr; i++)

				__mptcp_subflow_connect(sk, &local->addr, &addrs[i]);

			spin_lock_bh(&msk->pm.lock);

			return;

		}



		/* lookup failed, avoid fourther attempts later */

		msk->pm.local_addr_used = local_addr_max;

		check_work_pending(msk);

	}

	check_work_pending(msk);

}



static void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
@@ -736,6 +767,7 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk, 
			msk->pm.subflows--;

			__MPTCP_INC_STATS(sock_net(sk), rm_type);

		}

		__set_bit(rm_list->ids[1], msk->pm.id_avail_bitmap);

		if (!removed)

			continue;
@@ -765,6 +797,9 @@ void mptcp_pm_nl_work(struct mptcp_sock *msk) 


	msk_owned_by_me(msk);



	if (!(pm->status & MPTCP_PM_WORK_MASK))

		return;



	spin_lock_bh(&msk->pm.lock);



	pr_debug("msk=%p status=%x", msk, pm->status);
@@ -810,7 +845,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, 
	/* to keep the code simple, don't do IDR-like allocation for address ID,

	 * just bail when we exceed limits

	 */

	if (pernet->next_id == MAX_ADDR_ID)

	if (pernet->next_id == MPTCP_PM_MAX_ADDR_ID)

		pernet->next_id = 1;

	if (pernet->addrs >= MPTCP_PM_ADDR_MAX)

		goto out;
@@ -830,7 +865,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, 
	if (!entry->addr.id) {

find_next:

		entry->addr.id = find_next_zero_bit(pernet->id_bitmap,

						    MAX_ADDR_ID + 1,

						    MPTCP_PM_MAX_ADDR_ID + 1,

						    pernet->next_id);

		if (!entry->addr.id && pernet->next_id != 1) {

			pernet->next_id = 1;
@@ -1197,18 +1232,6 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info) 
	return 0;

}



static struct mptcp_pm_addr_entry *

__lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)

{

	struct mptcp_pm_addr_entry *entry;



	list_for_each_entry(entry, &pernet->local_addr_list, list) {

		if (entry->addr.id == id)

			return entry;

	}

	return NULL;

}



int mptcp_pm_get_flags_and_ifindex_by_id(struct net *net, unsigned int id,

					 u8 *flags, int *ifindex)

{
@@ -1467,7 +1490,7 @@ static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info) 
	list_splice_init(&pernet->local_addr_list, &free_list);

	__reset_counters(pernet);

	pernet->next_id = 1;

	bitmap_zero(pernet->id_bitmap, MAX_ADDR_ID + 1);

	bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);

	spin_unlock_bh(&pernet->lock);

	mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list);

	synchronize_rcu();
@@ -1577,7 +1600,7 @@ static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg, 
	pernet = net_generic(net, pm_nl_pernet_id);



	spin_lock_bh(&pernet->lock);

	for (i = id; i < MAX_ADDR_ID + 1; i++) {

	for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {

		if (test_bit(i, pernet->id_bitmap)) {

			entry = __lookup_addr_by_id(pernet, i);

			if (!entry)

net/mptcp/protocol.c

+1 −2
Original line number Diff line number Diff line
@@ -2488,7 +2488,6 @@ static void mptcp_worker(struct work_struct *work) 


	mptcp_check_fastclose(msk);



	if (msk->pm.status)

	mptcp_pm_nl_work(msk);



	if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))

net/mptcp/protocol.h

+11 −1
Original line number Diff line number Diff line
@@ -173,16 +173,25 @@ enum mptcp_pm_status { 
	MPTCP_PM_ADD_ADDR_SEND_ACK,

	MPTCP_PM_RM_ADDR_RECEIVED,

	MPTCP_PM_ESTABLISHED,

	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */

	MPTCP_PM_SUBFLOW_ESTABLISHED,

	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */

	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is

					 * accounted int id_avail_bitmap

					 */

};



/* Status bits below MPTCP_PM_ALREADY_ESTABLISHED need pm worker actions */

#define MPTCP_PM_WORK_MASK ((1 << MPTCP_PM_ALREADY_ESTABLISHED) - 1)



enum mptcp_addr_signal_status {

	MPTCP_ADD_ADDR_SIGNAL,

	MPTCP_ADD_ADDR_ECHO,

	MPTCP_RM_ADDR_SIGNAL,

};



/* max value of mptcp_addr_info.id */

#define MPTCP_PM_MAX_ADDR_ID		U8_MAX



struct mptcp_pm_data {

	struct mptcp_addr_info local;

	struct mptcp_addr_info remote;
@@ -201,6 +210,7 @@ struct mptcp_pm_data { 
	u8		local_addr_used;

	u8		subflows;

	u8		status;

	DECLARE_BITMAP(id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);

	struct mptcp_rm_list rm_list_tx;

	struct mptcp_rm_list rm_list_rx;

};

tools/testing/selftests/net/mptcp/mptcp_join.sh

+4 −1
Original line number Diff line number Diff line
@@ -1071,7 +1071,10 @@ signal_address_tests() 
	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags signal

	ip netns exec $ns2 ./pm_nl_ctl add 10.0.4.2 flags signal

	run_tests $ns1 $ns2 10.0.1.1

	chk_add_nr 4 4



	# the server will not signal the address terminating

	# the MPC subflow

	chk_add_nr 3 3

}



link_failure_tests()