Commit d045b9eb authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: introduce implicit endpoints 



In some edge scenarios, an MPTCP subflows can use a local address
mapped by a "implicit" endpoint created by the in-kernel path manager.

Such endpoints presence can be confusing, as it's creation is hard
to track and will prevent the later endpoint creation from the user-space
using the same address.

Define a new endpoint flag to mark implicit endpoints and allow the
user-space to replace implicit them with user-provided data at endpoint
creation time.

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 6fa0174a

include/uapi/linux/mptcp.h

+1 −0
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ enum { 
#define MPTCP_PM_ADDR_FLAG_SUBFLOW			(1 << 1)

#define MPTCP_PM_ADDR_FLAG_BACKUP			(1 << 2)

#define MPTCP_PM_ADDR_FLAG_FULLMESH			(1 << 3)

#define MPTCP_PM_ADDR_FLAG_IMPLICIT			(1 << 4)



enum {

	MPTCP_PM_CMD_UNSPEC,

net/mptcp/pm_netlink.c

+44 −17
Original line number Diff line number Diff line
@@ -877,10 +877,18 @@ static bool address_use_port(struct mptcp_pm_addr_entry *entry) 
		MPTCP_PM_ADDR_FLAG_SIGNAL;

}



/* caller must ensure the RCU grace period is already elapsed */

static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)

{

	if (entry->lsk)

		sock_release(entry->lsk);

	kfree(entry);

}



static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,

					     struct mptcp_pm_addr_entry *entry)

{

	struct mptcp_pm_addr_entry *cur;

	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;

	unsigned int addr_max;

	int ret = -EINVAL;
@@ -901,8 +909,22 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, 
	list_for_each_entry(cur, &pernet->local_addr_list, list) {

		if (addresses_equal(&cur->addr, &entry->addr,

				    address_use_port(entry) &&

				    address_use_port(cur)))

				    address_use_port(cur))) {

			/* allow replacing the exiting endpoint only if such

			 * endpoint is an implicit one and the user-space

			 * did not provide an endpoint id

			 */

			if (!(cur->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT))

				goto out;

			if (entry->addr.id)

				goto out;



			pernet->addrs--;

			entry->addr.id = cur->addr.id;

			list_del_rcu(&cur->list);

			del_entry = cur;

			break;

		}

	}



	if (!entry->addr.id) {
@@ -938,6 +960,12 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, 


out:

	spin_unlock_bh(&pernet->lock);



	/* just replaced an existing entry, free it */

	if (del_entry) {

		synchronize_rcu();

		__mptcp_pm_release_addr_entry(del_entry);

	}

	return ret;

}
@@ -1036,7 +1064,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) 
	entry->addr.id = 0;

	entry->addr.port = 0;

	entry->ifindex = 0;

	entry->flags = 0;

	entry->flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;

	entry->lsk = NULL;

	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);

	if (ret < 0)
@@ -1249,6 +1277,11 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info) 
		return -EINVAL;

	}



	if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {

		GENL_SET_ERR_MSG(info, "can't create IMPLICIT endpoint");

		return -EINVAL;

	}



	entry = kmalloc(sizeof(*entry), GFP_KERNEL);

	if (!entry) {

		GENL_SET_ERR_MSG(info, "can't allocate addr");
@@ -1333,11 +1366,12 @@ static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk, 
}



static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,

						   struct mptcp_addr_info *addr)

						   const struct mptcp_pm_addr_entry *entry)

{

	struct mptcp_sock *msk;

	long s_slot = 0, s_num = 0;

	const struct mptcp_addr_info *addr = &entry->addr;

	struct mptcp_rm_list list = { .nr = 0 };

	long s_slot = 0, s_num = 0;

	struct mptcp_sock *msk;



	pr_debug("remove_id=%d", addr->id);
@@ -1354,7 +1388,8 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net, 


		lock_sock(sk);

		remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);

		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow);

		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&

					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));

		if (remove_subflow)

			mptcp_pm_remove_subflow(msk, &list);

		release_sock(sk);
@@ -1367,14 +1402,6 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net, 
	return 0;

}



/* caller must ensure the RCU grace period is already elapsed */

static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)

{

	if (entry->lsk)

		sock_release(entry->lsk);

	kfree(entry);

}



static int mptcp_nl_remove_id_zero_address(struct net *net,

					   struct mptcp_addr_info *addr)

{
@@ -1451,7 +1478,7 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info) 
	__clear_bit(entry->addr.id, pernet->id_bitmap);

	spin_unlock_bh(&pernet->lock);



	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);

	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), entry);

	synchronize_rcu();

	__mptcp_pm_release_addr_entry(entry);

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

+2 −2
Original line number Diff line number Diff line
@@ -1938,7 +1938,7 @@ backup_tests() 
	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow backup

	chk_join_nr "single address, backup" 1 1 1

	chk_add_nr 1 1

	chk_prio_nr 1 0

	chk_prio_nr 1 1



	# single address with port, backup

	reset
@@ -1948,7 +1948,7 @@ backup_tests() 
	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow backup

	chk_join_nr "single address with port, backup" 1 1 1

	chk_add_nr 1 1

	chk_prio_nr 1 0

	chk_prio_nr 1 1

}



add_addr_ports_tests()