[PATCH net-next 00/15] mptcp: pm: special case for c-flag + luminar endp

[PATCH net-next 00/15] mptcp: pm: special case for c-flag + luminar endp

[Matthieu Baerts (NGI0)]

Here are some patches for the MPTCP PM, including some refactoring that
I thought it would be best to send at the end of a cycle to avoid
conflicts between net and net-next that could last a few weeks.

The most interesting changes are in the first and last patch, the rest
are patches refactoring the code & tests to validate the modifications.

- Patches 1 & 2: When servers set the C-flag in their MP_CAPABLE to tell
  clients not to create subflows to the initial address and port -- e.g.
  a deployment behind a L4 load balancer like a typical CDN deployment
  -- clients will not use their other endpoints when default settings
  are used. That's because the in-kernel path-manager uses the 'subflow'
  endpoints to create subflows only to the initial address and port. The
  first patch fixes that (for >=v5.14), and the second one validates it.

- Patches 3-14: various patches refactoring the code around the
  in-kernel PM (mainly): split too long functions, rename variables and
  functions to avoid confusions, reduce structure size, and compare IDs
  instead of IP addresses. Note that one patch modifies one internal
  variable used in one BPF selftest.

- Patch 15: ability to control endpoints that are used in reaction to a
  new address announced by the other peer. With that, endpoints can be
  used only once.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Notes:
 - Patches 1 & 2 are sent to net-next on purpose: to delay a bit the
   backports, just in case. Plus we are at the end of a cycle, and not
   to delay the other refactoring patches.
 - Sorry, I wanted to send this series earlier on, but due to some
   unrelated issues (and holiday), it got delayed. Most patches are
   pure refactoring ones.

---
Matthieu Baerts (NGI0) (15):
      mptcp: pm: in-kernel: usable client side with C-flag
      selftests: mptcp: join: validate C-flag + def limit
      mptcp: pm: in-kernel: refactor fill_local_addresses_vec
      mptcp: pm: in-kernel: refactor fill_remote_addresses_vec
      mptcp: pm: rename 'subflows' to 'extra_subflows'
      mptcp: pm: in-kernel: rename 'subflows_max' to 'limit_extra_subflows'
      mptcp: pm: in-kernel: rename 'add_addr_signal_max' to 'endp_signal_max'
      mptcp: pm: in-kernel: rename 'add_addr_accept_max' to 'limit_add_addr_accepted'
      mptcp: pm: in-kernel: rename 'local_addr_max' to 'endp_subflow_max'
      mptcp: pm: in-kernel: rename 'local_addr_list' to 'endp_list'
      mptcp: pm: in-kernel: rename 'addrs' to 'endpoints'
      mptcp: pm: in-kernel: remove stale_loss_cnt
      mptcp: pm: in-kernel: reduce pernet struct size
      mptcp: pm: in-kernel: compare IDs instead of addresses
      mptcp: pm: in-kernel: add laminar endpoints

 include/uapi/linux/mptcp.h                        |  11 +-
 net/mptcp/pm.c                                    |  32 +-
 net/mptcp/pm_kernel.c                             | 569 ++++++++++++++--------
 net/mptcp/pm_userspace.c                          |   2 +-
 net/mptcp/protocol.h                              |  21 +-
 net/mptcp/sockopt.c                               |  22 +-
 tools/testing/selftests/bpf/progs/mptcp_subflow.c |   2 +-
 tools/testing/selftests/net/mptcp/mptcp_join.sh   |  11 +
 8 files changed, 441 insertions(+), 229 deletions(-)
---
base-commit: a1f1f2422e098485b09e55a492de05cf97f9954d
change-id: 20250925-net-next-mptcp-c-flag-laminar-f8442e4d4bd9

Best regards,
-- 
Matthieu Baerts (NGI0) <matttbe@kernel.org>

[PATCH net-next 01/15] mptcp: pm: in-kernel: usable client side with C-flag

[Matthieu Baerts (NGI0)]

When servers set the C-flag in their MP_CAPABLE to tell clients not to
create subflows to the initial address and port, clients will likely not
use their other endpoints. That's because the in-kernel path-manager
uses the 'subflow' endpoints to create subflows only to the initial
address and port.

If the limits have not been modified to accept ADD_ADDR, the client
doesn't try to establish new subflows. If the limits accept ADD_ADDR,
the routing routes will be used to select the source IP.

The C-flag is typically set when the server is operating behind a legacy
Layer 4 load balancer, or using anycast IP address. Clients having their
different 'subflow' endpoints setup, don't end up creating multiple
subflows as expected, and causing some deployment issues.

A special case is then added here: when servers set the C-flag in the
MPC and directly sends an ADD_ADDR, this single ADD_ADDR is accepted.
The 'subflows' endpoints will then be used with this new remote IP and
port. This exception is only allowed when the ADD_ADDR is sent
immediately after the 3WHS, and makes the client switching to the 'fully
established' mode. After that, 'select_local_address()' will not be able
to find any subflows, because 'id_avail_bitmap' will be filled in
mptcp_pm_create_subflow_or_signal_addr(), when switching to 'fully
established' mode.

Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/536
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm.c        |  7 +++++--
 net/mptcp/pm_kernel.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
 net/mptcp/protocol.h  |  8 ++++++++
 3 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 204e1f61212e2be77a8476f024b59be67d04b80a..584cab90aa6eff4c01cdf4ca4d3dce8894829920 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -637,9 +637,12 @@ void mptcp_pm_add_addr_received(const struct sock *ssk,
 		} else {
 			__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
 		}
-	/* id0 should not have a different address */
+	/* - id0 should not have a different address
+	 * - special case for C-flag: linked to fill_local_addresses_vec()
+	 */
 	} else if ((addr->id == 0 && !mptcp_pm_is_init_remote_addr(msk, addr)) ||
-		   (addr->id > 0 && !READ_ONCE(pm->accept_addr))) {
+		   (addr->id > 0 && !READ_ONCE(pm->accept_addr) &&
+		    !mptcp_pm_add_addr_c_flag_case(msk))) {
 		mptcp_pm_announce_addr(msk, addr, true);
 		mptcp_pm_add_addr_send_ack(msk);
 	} else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) {
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 667803d72b643a0bb98365003b136c53f2a9a975..8c46493a0835b0e2d5e70950662ae6e845393777 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -389,10 +389,12 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	struct mptcp_addr_info mpc_addr;
 	struct pm_nl_pernet *pernet;
 	unsigned int subflows_max;
+	bool c_flag_case;
 	int i = 0;
 
 	pernet = pm_nl_get_pernet_from_msk(msk);
 	subflows_max = mptcp_pm_get_subflows_max(msk);
+	c_flag_case = remote->id && mptcp_pm_add_addr_c_flag_case(msk);
 
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
 
@@ -405,12 +407,27 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 			continue;
 
 		if (msk->pm.subflows < subflows_max) {
+			bool is_id0;
+
 			locals[i].addr = entry->addr;
 			locals[i].flags = entry->flags;
 			locals[i].ifindex = entry->ifindex;
 
+			is_id0 = mptcp_addresses_equal(&locals[i].addr,
+						       &mpc_addr,
+						       locals[i].addr.port);
+
+			if (c_flag_case &&
+			    (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)) {
+				__clear_bit(locals[i].addr.id,
+					    msk->pm.id_avail_bitmap);
+
+				if (!is_id0)
+					msk->pm.local_addr_used++;
+			}
+
 			/* Special case for ID0: set the correct ID */
-			if (mptcp_addresses_equal(&locals[i].addr, &mpc_addr, locals[i].addr.port))
+			if (is_id0)
 				locals[i].addr.id = 0;
 
 			msk->pm.subflows++;
@@ -419,6 +436,37 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	}
 	rcu_read_unlock();
 
+	/* Special case: peer sets the C flag, accept one ADD_ADDR if default
+	 * limits are used -- accepting no ADD_ADDR -- and use subflow endpoints
+	 */
+	if (!i && c_flag_case) {
+		unsigned int local_addr_max = mptcp_pm_get_local_addr_max(msk);
+
+		while (msk->pm.local_addr_used < local_addr_max &&
+		       msk->pm.subflows < subflows_max) {
+			struct mptcp_pm_local *local = &locals[i];
+
+			if (!select_local_address(pernet, msk, local))
+				break;
+
+			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+
+			if (!mptcp_pm_addr_families_match(sk, &local->addr,
+							  remote))
+				continue;
+
+			if (mptcp_addresses_equal(&local->addr, &mpc_addr,
+						  local->addr.port))
+				continue;
+
+			msk->pm.local_addr_used++;
+			msk->pm.subflows++;
+			i++;
+		}
+
+		return i;
+	}
+
 	/* If the array is empty, fill in the single
 	 * 'IPADDRANY' local address
 	 */
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index a1787a1344ac1bbeefdb4548740d6aef980b79e7..cbe54331e5c745989af50409d9cb79c6d90a8201 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1199,6 +1199,14 @@ static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
 	spin_unlock_bh(&msk->pm.lock);
 }
 
+static inline bool mptcp_pm_add_addr_c_flag_case(struct mptcp_sock *msk)
+{
+	return READ_ONCE(msk->pm.remote_deny_join_id0) &&
+	       msk->pm.local_addr_used == 0 &&
+	       mptcp_pm_get_add_addr_accept_max(msk) == 0 &&
+	       msk->pm.subflows < mptcp_pm_get_subflows_max(msk);
+}
+
 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
 
 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)

-- 
2.51.0

[PATCH net-next 02/15] selftests: mptcp: join: validate C-flag + def limit

[Matthieu Baerts (NGI0)]

The previous commit adds an exception for the C-flag case. The
'mptcp_join.sh' selftest is extended to validate this case.

In this subtest, there is a typical CDN deployment with a client where
MPTCP endpoints have been 'automatically' configured:

- the server set net.mptcp.allow_join_initial_addr_port=0

- the client has multiple 'subflow' endpoints, and the default limits:
  not accepting ADD_ADDRs.

Without the parent patch, the client is not able to establish new
subflows using its 'subflow' endpoints. The parent commit fixes that.

The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.

Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 6055ee5762e13108e5e2924a0e77d58da584d008..a94b3960ad5e009dbead66b6ff2aa01f70aa3e1f 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -3306,6 +3306,17 @@ deny_join_id0_tests()
 		run_tests $ns1 $ns2 10.0.1.1
 		chk_join_nr 1 1 1
 	fi
+
+	# default limits, server deny join id 0 + signal
+	if reset_with_allow_join_id0 "default limits, server deny join id 0" 0 1; then
+		pm_nl_set_limits $ns1 0 2
+		pm_nl_set_limits $ns2 0 2
+		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
+		pm_nl_add_endpoint $ns2 10.0.3.2 flags subflow
+		pm_nl_add_endpoint $ns2 10.0.4.2 flags subflow
+		run_tests $ns1 $ns2 10.0.1.1
+		chk_join_nr 2 2 2
+	fi
 }
 
 fullmesh_tests()

-- 
2.51.0

[PATCH net-next 03/15] mptcp: pm: in-kernel: refactor fill_local_addresses_vec

[Matthieu Baerts (NGI0)]

Before this modification, this function was quite long with many levels
of indentations.

Each case can be split in a dedicated function: fullmesh, C flag, any.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 199 +++++++++++++++++++++++++++++---------------------
 1 file changed, 116 insertions(+), 83 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 8c46493a0835b0e2d5e70950662ae6e845393777..c8f2af2277c2c28bc7ad393bc4ef8507ddd3a875 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -377,116 +377,149 @@ static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
 	mptcp_pm_create_subflow_or_signal_addr(msk);
 }
 
-/* Fill all the local addresses into the array addrs[],
- * and return the array size.
- */
-static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
-					     struct mptcp_addr_info *remote,
-					     struct mptcp_pm_local *locals)
+static unsigned int
+fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
+				  struct mptcp_addr_info *remote,
+				  struct mptcp_pm_local *locals,
+				  bool c_flag_case)
 {
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	unsigned int subflows_max = mptcp_pm_get_subflows_max(msk);
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
 	struct mptcp_addr_info mpc_addr;
-	struct pm_nl_pernet *pernet;
-	unsigned int subflows_max;
-	bool c_flag_case;
+	struct mptcp_pm_local *local;
 	int i = 0;
 
-	pernet = pm_nl_get_pernet_from_msk(msk);
-	subflows_max = mptcp_pm_get_subflows_max(msk);
-	c_flag_case = remote->id && mptcp_pm_add_addr_c_flag_case(msk);
-
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		bool is_id0;
+
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
 			continue;
 
 		if (!mptcp_pm_addr_families_match(sk, &entry->addr, remote))
 			continue;
 
-		if (msk->pm.subflows < subflows_max) {
-			bool is_id0;
+		local = &locals[i];
+		local->addr = entry->addr;
+		local->flags = entry->flags;
+		local->ifindex = entry->ifindex;
 
-			locals[i].addr = entry->addr;
-			locals[i].flags = entry->flags;
-			locals[i].ifindex = entry->ifindex;
+		is_id0 = mptcp_addresses_equal(&local->addr, &mpc_addr,
+					       local->addr.port);
 
-			is_id0 = mptcp_addresses_equal(&locals[i].addr,
-						       &mpc_addr,
-						       locals[i].addr.port);
+		if (c_flag_case &&
+		    (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)) {
+			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
 
-			if (c_flag_case &&
-			    (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)) {
-				__clear_bit(locals[i].addr.id,
-					    msk->pm.id_avail_bitmap);
-
-				if (!is_id0)
-					msk->pm.local_addr_used++;
-			}
-
-			/* Special case for ID0: set the correct ID */
-			if (is_id0)
-				locals[i].addr.id = 0;
-
-			msk->pm.subflows++;
-			i++;
+			if (!is_id0)
+				msk->pm.local_addr_used++;
 		}
+
+		/* Special case for ID0: set the correct ID */
+		if (is_id0)
+			local->addr.id = 0;
+
+		msk->pm.subflows++;
+		i++;
+
+		if (msk->pm.subflows >= subflows_max)
+			break;
 	}
 	rcu_read_unlock();
 
+	return i;
+}
+
+static unsigned int
+fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
+				struct mptcp_addr_info *remote,
+				struct mptcp_pm_local *locals)
+{
+	unsigned int local_addr_max = mptcp_pm_get_local_addr_max(msk);
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	unsigned int subflows_max = mptcp_pm_get_subflows_max(msk);
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_addr_info mpc_addr;
+	struct mptcp_pm_local *local;
+	int i = 0;
+
+	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+
+	while (msk->pm.local_addr_used < local_addr_max) {
+		local = &locals[i];
+
+		if (!select_local_address(pernet, msk, local))
+			break;
+
+		__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+
+		if (!mptcp_pm_addr_families_match(sk, &local->addr, remote))
+			continue;
+
+		if (mptcp_addresses_equal(&local->addr, &mpc_addr,
+					  local->addr.port))
+			continue;
+
+		msk->pm.local_addr_used++;
+		msk->pm.subflows++;
+		i++;
+
+		if (msk->pm.subflows >= subflows_max)
+			break;
+	}
+
+	return i;
+}
+
+static unsigned int
+fill_local_address_any(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
+		       struct mptcp_pm_local *local)
+{
+	struct sock *sk = (struct sock *)msk;
+
+	memset(local, 0, sizeof(*local));
+	local->addr.family =
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+			remote->family == AF_INET6 &&
+			ipv6_addr_v4mapped(&remote->addr6) ? AF_INET :
+#endif
+			remote->family;
+
+	if (!mptcp_pm_addr_families_match(sk, &local->addr, remote))
+		return 0;
+
+	msk->pm.subflows++;
+
+	return 1;
+}
+
+/* Fill all the local addresses into the array addrs[],
+ * and return the array size.
+ */
+static unsigned int
+fill_local_addresses_vec(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
+			 struct mptcp_pm_local *locals)
+{
+	bool c_flag_case = remote->id && mptcp_pm_add_addr_c_flag_case(msk);
+	int i;
+
+	/* If there is at least one MPTCP endpoint with a fullmesh flag */
+	i = fill_local_addresses_vec_fullmesh(msk, remote, locals, c_flag_case);
+	if (i)
+		return i;
+
 	/* Special case: peer sets the C flag, accept one ADD_ADDR if default
 	 * limits are used -- accepting no ADD_ADDR -- and use subflow endpoints
 	 */
-	if (!i && c_flag_case) {
-		unsigned int local_addr_max = mptcp_pm_get_local_addr_max(msk);
+	if (c_flag_case)
+		return fill_local_addresses_vec_c_flag(msk, remote, locals);
 
-		while (msk->pm.local_addr_used < local_addr_max &&
-		       msk->pm.subflows < subflows_max) {
-			struct mptcp_pm_local *local = &locals[i];
-
-			if (!select_local_address(pernet, msk, local))
-				break;
-
-			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
-
-			if (!mptcp_pm_addr_families_match(sk, &local->addr,
-							  remote))
-				continue;
-
-			if (mptcp_addresses_equal(&local->addr, &mpc_addr,
-						  local->addr.port))
-				continue;
-
-			msk->pm.local_addr_used++;
-			msk->pm.subflows++;
-			i++;
-		}
-
-		return i;
-	}
-
-	/* If the array is empty, fill in the single
-	 * 'IPADDRANY' local address
-	 */
-	if (!i) {
-		memset(&locals[i], 0, sizeof(locals[i]));
-		locals[i].addr.family =
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-			       remote->family == AF_INET6 &&
-			       ipv6_addr_v4mapped(&remote->addr6) ? AF_INET :
-#endif
-			       remote->family;
-
-		if (!mptcp_pm_addr_families_match(sk, &locals[i].addr, remote))
-			return 0;
-
-		msk->pm.subflows++;
-		i++;
-	}
-
-	return i;
+	/* No special case: fill in the single 'IPADDRANY' local address */
+	return fill_local_address_any(msk, remote, &locals[0]);
 }
 
 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)

-- 
2.51.0

[PATCH net-next 04/15] mptcp: pm: in-kernel: refactor fill_remote_addresses_vec

[Matthieu Baerts (NGI0)]

Before this modification, this function was quite long with many levels
of indentations.

Each case can be split in a dedicated function: fullmesh, non-fullmesh.

To remove one level of indentation, msk->pm.subflows >= subflows_max is
now checked after having added one subflow, and stops the loop if it is
no longer possible to add new subflows. This is fine to do this because
this function should only be called if msk->pm.subflows < subflows_max.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 116 +++++++++++++++++++++++++++++---------------------
 1 file changed, 67 insertions(+), 49 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index c8f2af2277c2c28bc7ad393bc4ef8507ddd3a875..a82c077b8a20ccda2b4fc3cf7a55141bd01760f2 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -159,74 +159,92 @@ select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
 	return found;
 }
 
-/* Fill all the remote addresses into the array addrs[],
- * and return the array size.
- */
-static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk,
-					      struct mptcp_addr_info *local,
-					      bool fullmesh,
-					      struct mptcp_addr_info *addrs)
+static unsigned int
+fill_remote_addr(struct mptcp_sock *msk, struct mptcp_addr_info *local,
+		 struct mptcp_addr_info *addrs)
 {
 	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
+	struct mptcp_addr_info remote = { 0 };
+	struct sock *sk = (struct sock *)msk;
+
+	if (deny_id0)
+		return 0;
+
+	mptcp_remote_address((struct sock_common *)sk, &remote);
+
+	if (!mptcp_pm_addr_families_match(sk, local, &remote))
+		return 0;
+
+	msk->pm.subflows++;
+	*addrs = remote;
+
+	return 1;
+}
+
+static unsigned int
+fill_remote_addresses_fullmesh(struct mptcp_sock *msk,
+			       struct mptcp_addr_info *local,
+			       struct mptcp_addr_info *addrs)
+{
+	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
+	DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
 	struct sock *sk = (struct sock *)msk, *ssk;
 	struct mptcp_subflow_context *subflow;
-	struct mptcp_addr_info remote = { 0 };
 	unsigned int subflows_max;
 	int i = 0;
 
 	subflows_max = mptcp_pm_get_subflows_max(msk);
-	mptcp_remote_address((struct sock_common *)sk, &remote);
 
-	/* Non-fullmesh endpoint, fill in the single entry
-	 * corresponding to the primary MPC subflow remote address
+	/* Forbid creation of new subflows matching existing ones, possibly
+	 * already created by incoming ADD_ADDR
 	 */
-	if (!fullmesh) {
-		if (deny_id0)
-			return 0;
+	bitmap_zero(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+	mptcp_for_each_subflow(msk, subflow)
+		if (READ_ONCE(subflow->local_id) == local->id)
+			__set_bit(subflow->remote_id, unavail_id);
 
-		if (!mptcp_pm_addr_families_match(sk, local, &remote))
-			return 0;
+	mptcp_for_each_subflow(msk, subflow) {
+		ssk = mptcp_subflow_tcp_sock(subflow);
+		mptcp_remote_address((struct sock_common *)ssk, &addrs[i]);
+		addrs[i].id = READ_ONCE(subflow->remote_id);
+		if (deny_id0 && !addrs[i].id)
+			continue;
 
+		if (test_bit(addrs[i].id, unavail_id))
+			continue;
+
+		if (!mptcp_pm_addr_families_match(sk, local, &addrs[i]))
+			continue;
+
+		/* forbid creating multiple address towards this id */
+		__set_bit(addrs[i].id, unavail_id);
 		msk->pm.subflows++;
-		addrs[i++] = remote;
-	} else {
-		DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+		i++;
 
-		/* Forbid creation of new subflows matching existing
-		 * ones, possibly already created by incoming ADD_ADDR
-		 */
-		bitmap_zero(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
-		mptcp_for_each_subflow(msk, subflow)
-			if (READ_ONCE(subflow->local_id) == local->id)
-				__set_bit(subflow->remote_id, unavail_id);
-
-		mptcp_for_each_subflow(msk, subflow) {
-			ssk = mptcp_subflow_tcp_sock(subflow);
-			mptcp_remote_address((struct sock_common *)ssk, &addrs[i]);
-			addrs[i].id = READ_ONCE(subflow->remote_id);
-			if (deny_id0 && !addrs[i].id)
-				continue;
-
-			if (test_bit(addrs[i].id, unavail_id))
-				continue;
-
-			if (!mptcp_pm_addr_families_match(sk, local, &addrs[i]))
-				continue;
-
-			if (msk->pm.subflows < subflows_max) {
-				/* forbid creating multiple address towards
-				 * this id
-				 */
-				__set_bit(addrs[i].id, unavail_id);
-				msk->pm.subflows++;
-				i++;
-			}
-		}
+		if (msk->pm.subflows >= subflows_max)
+			break;
 	}
 
 	return i;
 }
 
+/* Fill all the remote addresses into the array addrs[],
+ * and return the array size.
+ */
+static unsigned int
+fill_remote_addresses_vec(struct mptcp_sock *msk, struct mptcp_addr_info *local,
+			  bool fullmesh, struct mptcp_addr_info *addrs)
+{
+	/* Non-fullmesh: fill in the single entry corresponding to the primary
+	 * MPC subflow remote address, and return 1, corresponding to 1 entry.
+	 */
+	if (!fullmesh)
+		return fill_remote_addr(msk, local, addrs);
+
+	/* Fullmesh endpoint: fill all possible remote addresses */
+	return fill_remote_addresses_fullmesh(msk, local, addrs);
+}
+
 static struct mptcp_pm_addr_entry *
 __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 {

-- 
2.51.0

[PATCH net-next 05/15] mptcp: pm: rename 'subflows' to 'extra_subflows'

[Matthieu Baerts (NGI0)]

A few variables linked to the Path-Managers are confusing, and it would
help current and future developers, to clarify them.

One of them is 'subflows', which in fact represents the number of extra
subflows: all the additional subflows created after the initial one, and
not the total number of subflows.

While at it, add an additional name for the corresponding variable in
MPTCP INFO: mptcpi_extra_subflows. Not to break the current uAPI, the
new name is added as a 'define' pointing to the former name. This will
then also help userspace devs.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 include/uapi/linux/mptcp.h                        |  1 +
 net/mptcp/pm.c                                    | 13 ++++++------
 net/mptcp/pm_kernel.c                             | 24 +++++++++++------------
 net/mptcp/pm_userspace.c                          |  2 +-
 net/mptcp/protocol.h                              |  6 +++---
 net/mptcp/sockopt.c                               |  4 ++--
 tools/testing/selftests/bpf/progs/mptcp_subflow.c |  2 +-
 7 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 15eef878690b8556af21be8d959b6a2c9fe617d3..f807c8dba56e7eb278fce0ad3184de3d0e24399b 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -42,6 +42,7 @@
 
 struct mptcp_info {
 	__u8	mptcpi_subflows;
+	#define mptcpi_extra_subflows mptcpi_subflows
 	__u8	mptcpi_add_addr_signal;
 	__u8	mptcpi_add_addr_accepted;
 	__u8	mptcpi_subflows_max;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 584cab90aa6eff4c01cdf4ca4d3dce8894829920..332e96bdadc0b936704188e5c9666cba97817b16 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -489,7 +489,7 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 	if (mptcp_pm_is_userspace(msk)) {
 		if (mptcp_userspace_pm_active(msk)) {
 			spin_lock_bh(&pm->lock);
-			pm->subflows++;
+			pm->extra_subflows++;
 			spin_unlock_bh(&pm->lock);
 			return true;
 		}
@@ -498,8 +498,9 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 
 	subflows_max = mptcp_pm_get_subflows_max(msk);
 
-	pr_debug("msk=%p subflows=%d max=%d allow=%d\n", msk, pm->subflows,
-		 subflows_max, READ_ONCE(pm->accept_subflow));
+	pr_debug("msk=%p subflows=%d max=%d allow=%d\n", msk,
+		 pm->extra_subflows, subflows_max,
+		 READ_ONCE(pm->accept_subflow));
 
 	/* try to avoid acquiring the lock below */
 	if (!READ_ONCE(pm->accept_subflow))
@@ -507,8 +508,8 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 
 	spin_lock_bh(&pm->lock);
 	if (READ_ONCE(pm->accept_subflow)) {
-		ret = pm->subflows < subflows_max;
-		if (ret && ++pm->subflows == subflows_max)
+		ret = pm->extra_subflows < subflows_max;
+		if (ret && ++pm->extra_subflows == subflows_max)
 			WRITE_ONCE(pm->accept_subflow, false);
 	}
 	spin_unlock_bh(&pm->lock);
@@ -594,7 +595,7 @@ void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
 	if (mptcp_pm_is_userspace(msk)) {
 		if (update_subflows) {
 			spin_lock_bh(&pm->lock);
-			pm->subflows--;
+			pm->extra_subflows--;
 			spin_unlock_bh(&pm->lock);
 		}
 		return;
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index a82c077b8a20ccda2b4fc3cf7a55141bd01760f2..20bee6fc06259a0211782c94c1693ffe79dae1b6 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -175,7 +175,7 @@ fill_remote_addr(struct mptcp_sock *msk, struct mptcp_addr_info *local,
 	if (!mptcp_pm_addr_families_match(sk, local, &remote))
 		return 0;
 
-	msk->pm.subflows++;
+	msk->pm.extra_subflows++;
 	*addrs = remote;
 
 	return 1;
@@ -218,10 +218,10 @@ fill_remote_addresses_fullmesh(struct mptcp_sock *msk,
 
 		/* forbid creating multiple address towards this id */
 		__set_bit(addrs[i].id, unavail_id);
-		msk->pm.subflows++;
+		msk->pm.extra_subflows++;
 		i++;
 
-		if (msk->pm.subflows >= subflows_max)
+		if (msk->pm.extra_subflows >= subflows_max)
 			break;
 	}
 
@@ -313,7 +313,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	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,
-		 msk->pm.subflows, subflows_max);
+		 msk->pm.extra_subflows, subflows_max);
 
 	/* check first for announce */
 	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
@@ -353,7 +353,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 subflow:
 	/* check if should create a new subflow */
 	while (msk->pm.local_addr_used < local_addr_max &&
-	       msk->pm.subflows < subflows_max) {
+	       msk->pm.extra_subflows < subflows_max) {
 		struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 		bool fullmesh;
 		int i, nr;
@@ -441,10 +441,10 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 		if (is_id0)
 			local->addr.id = 0;
 
-		msk->pm.subflows++;
+		msk->pm.extra_subflows++;
 		i++;
 
-		if (msk->pm.subflows >= subflows_max)
+		if (msk->pm.extra_subflows >= subflows_max)
 			break;
 	}
 	rcu_read_unlock();
@@ -483,10 +483,10 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 			continue;
 
 		msk->pm.local_addr_used++;
-		msk->pm.subflows++;
+		msk->pm.extra_subflows++;
 		i++;
 
-		if (msk->pm.subflows >= subflows_max)
+		if (msk->pm.extra_subflows >= subflows_max)
 			break;
 	}
 
@@ -510,7 +510,7 @@ fill_local_address_any(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
 	if (!mptcp_pm_addr_families_match(sk, &local->addr, remote))
 		return 0;
 
-	msk->pm.subflows++;
+	msk->pm.extra_subflows++;
 
 	return 1;
 }
@@ -586,7 +586,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 		if (remote.id)
 			msk->pm.add_addr_accepted++;
 		if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
-		    msk->pm.subflows >= subflows_max)
+		    msk->pm.extra_subflows >= subflows_max)
 			WRITE_ONCE(msk->pm.accept_addr, false);
 	}
 }
@@ -1427,7 +1427,7 @@ bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||
+	if (msk->pm.extra_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);
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index a715dcbe0146ed0c055d071c63257047a90a9afd..8cbc1920afb492a03eff84317b08684ee58c6bc9 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -419,7 +419,7 @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 	if (err)
 		mptcp_userspace_pm_delete_local_addr(msk, &entry);
 	else
-		msk->pm.subflows++;
+		msk->pm.extra_subflows++;
 	spin_unlock_bh(&msk->pm.lock);
 
  create_err:
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index cbe54331e5c745989af50409d9cb79c6d90a8201..ca68f9a7580149e43139ec6cc61a1e0b966e7a22 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -235,7 +235,7 @@ struct mptcp_pm_data {
 	u8		add_addr_accepted;
 	u8		local_addr_used;
 	u8		pm_type;
-	u8		subflows;
+	u8		extra_subflows;
 	u8		status;
 
 	);
@@ -1188,7 +1188,7 @@ unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
 /* called under PM lock */
 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
 {
-	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
+	if (--msk->pm.extra_subflows < mptcp_pm_get_subflows_max(msk))
 		WRITE_ONCE(msk->pm.accept_subflow, true);
 }
 
@@ -1204,7 +1204,7 @@ static inline bool mptcp_pm_add_addr_c_flag_case(struct mptcp_sock *msk)
 	return READ_ONCE(msk->pm.remote_deny_join_id0) &&
 	       msk->pm.local_addr_used == 0 &&
 	       mptcp_pm_get_add_addr_accept_max(msk) == 0 &&
-	       msk->pm.subflows < mptcp_pm_get_subflows_max(msk);
+	       msk->pm.extra_subflows < mptcp_pm_get_subflows_max(msk);
 }
 
 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 2abe6f1e99400498e915176c360be9281fd524f6..17966da80239d731de925f3e4211b3ee00f802e4 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -962,7 +962,7 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 
 	memset(info, 0, sizeof(*info));
 
-	info->mptcpi_subflows = READ_ONCE(msk->pm.subflows);
+	info->mptcpi_extra_subflows = READ_ONCE(msk->pm.extra_subflows);
 	info->mptcpi_add_addr_signal = READ_ONCE(msk->pm.add_addr_signaled);
 	info->mptcpi_add_addr_accepted = READ_ONCE(msk->pm.add_addr_accepted);
 	info->mptcpi_local_addr_used = READ_ONCE(msk->pm.local_addr_used);
@@ -996,7 +996,7 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	info->mptcpi_bytes_sent = msk->bytes_sent;
 	info->mptcpi_bytes_received = msk->bytes_received;
 	info->mptcpi_bytes_retrans = msk->bytes_retrans;
-	info->mptcpi_subflows_total = info->mptcpi_subflows +
+	info->mptcpi_subflows_total = info->mptcpi_extra_subflows +
 		__mptcp_has_initial_subflow(msk);
 	now = tcp_jiffies32;
 	info->mptcpi_last_data_sent = jiffies_to_msecs(now - msk->last_data_sent);
diff --git a/tools/testing/selftests/bpf/progs/mptcp_subflow.c b/tools/testing/selftests/bpf/progs/mptcp_subflow.c
index 70302477e326eecaef6aad4ecf899aa3d6606f23..41389e579578b7d6c0d9ffff520c9f3e930abb51 100644
--- a/tools/testing/selftests/bpf/progs/mptcp_subflow.c
+++ b/tools/testing/selftests/bpf/progs/mptcp_subflow.c
@@ -117,7 +117,7 @@ int _getsockopt_subflow(struct bpf_sockopt *ctx)
 		return 1;
 
 	msk = bpf_core_cast(sk, struct mptcp_sock);
-	if (msk->pm.subflows != 1) {
+	if (msk->pm.extra_subflows != 1) {
 		ctx->retval = -1;
 		return 1;
 	}

-- 
2.51.0

[PATCH net-next 06/15] mptcp: pm: in-kernel: rename 'subflows_max' to 'limit_extra_subflows'

[Matthieu Baerts (NGI0)]

A few variables linked to the in-kernel Path-Manager are confusing, and
it would help current and future developers, to clarify them.

One of them is 'subflows_max', which in fact represents the limit of
extra subflows: the limit set via 'ip mptcp limit subflows X' for
example. It is not linked to the maximum number of created / possible
subflows.

While at it, add an additional name for the corresponding variable in
MPTCP INFO: mptcpi_limit_extra_subflows. Not to break the current uAPI,
the new name is added as a 'define' pointing to the former name. This
will then also help userspace devs.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 include/uapi/linux/mptcp.h |  1 +
 net/mptcp/pm.c             | 12 ++++++------
 net/mptcp/pm_kernel.c      | 48 ++++++++++++++++++++++++----------------------
 net/mptcp/protocol.h       |  6 +++---
 net/mptcp/sockopt.c        |  4 ++--
 5 files changed, 37 insertions(+), 34 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index f807c8dba56e7eb278fce0ad3184de3d0e24399b..314200c61f150da445ff87debb154bfd98f324fc 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -46,6 +46,7 @@ struct mptcp_info {
 	__u8	mptcpi_add_addr_signal;
 	__u8	mptcpi_add_addr_accepted;
 	__u8	mptcpi_subflows_max;
+	#define mptcpi_limit_extra_subflows mptcpi_subflows_max
 	__u8	mptcpi_add_addr_signal_max;
 	__u8	mptcpi_add_addr_accepted_max;
 	__u32	mptcpi_flags;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 332e96bdadc0b936704188e5c9666cba97817b16..502f6c235e06c3f6fdca9dcf3a1d7b8e97fb9df6 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -483,7 +483,7 @@ void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int
 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_data *pm = &msk->pm;
-	unsigned int subflows_max;
+	unsigned int limit_extra_subflows;
 	int ret = 0;
 
 	if (mptcp_pm_is_userspace(msk)) {
@@ -496,10 +496,10 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 		return false;
 	}
 
-	subflows_max = mptcp_pm_get_subflows_max(msk);
+	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	pr_debug("msk=%p subflows=%d max=%d allow=%d\n", msk,
-		 pm->extra_subflows, subflows_max,
+		 pm->extra_subflows, limit_extra_subflows,
 		 READ_ONCE(pm->accept_subflow));
 
 	/* try to avoid acquiring the lock below */
@@ -508,8 +508,8 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 
 	spin_lock_bh(&pm->lock);
 	if (READ_ONCE(pm->accept_subflow)) {
-		ret = pm->extra_subflows < subflows_max;
-		if (ret && ++pm->extra_subflows == subflows_max)
+		ret = pm->extra_subflows < limit_extra_subflows;
+		if (ret && ++pm->extra_subflows == limit_extra_subflows)
 			WRITE_ONCE(pm->accept_subflow, false);
 	}
 	spin_unlock_bh(&pm->lock);
@@ -1029,7 +1029,7 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 	WRITE_ONCE(pm->pm_type, pm_type);
 
 	if (pm_type == MPTCP_PM_TYPE_KERNEL) {
-		bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
+		bool subflows_allowed = !!mptcp_pm_get_limit_extra_subflows(msk);
 
 		/* pm->work_pending must be only be set to 'true' when
 		 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 20bee6fc06259a0211782c94c1693ffe79dae1b6..db0d254d0e6b903fd8b920eb4cda628a811f7d58 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -23,7 +23,7 @@ struct pm_nl_pernet {
 	unsigned int		add_addr_signal_max;
 	unsigned int		add_addr_accept_max;
 	unsigned int		local_addr_max;
-	unsigned int		subflows_max;
+	unsigned int		limit_extra_subflows;
 	unsigned int		next_id;
 	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
 };
@@ -62,13 +62,13 @@ unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
 
-unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	return READ_ONCE(pernet->subflows_max);
+	return READ_ONCE(pernet->limit_extra_subflows);
 }
-EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
+EXPORT_SYMBOL_GPL(mptcp_pm_get_limit_extra_subflows);
 
 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
 {
@@ -190,10 +190,10 @@ fill_remote_addresses_fullmesh(struct mptcp_sock *msk,
 	DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
 	struct sock *sk = (struct sock *)msk, *ssk;
 	struct mptcp_subflow_context *subflow;
-	unsigned int subflows_max;
+	unsigned int limit_extra_subflows;
 	int i = 0;
 
-	subflows_max = mptcp_pm_get_subflows_max(msk);
+	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	/* Forbid creation of new subflows matching existing ones, possibly
 	 * already created by incoming ADD_ADDR
@@ -221,7 +221,7 @@ fill_remote_addresses_fullmesh(struct mptcp_sock *msk,
 		msk->pm.extra_subflows++;
 		i++;
 
-		if (msk->pm.extra_subflows >= subflows_max)
+		if (msk->pm.extra_subflows >= limit_extra_subflows)
 			break;
 	}
 
@@ -274,18 +274,18 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
 	struct sock *sk = (struct sock *)msk;
+	unsigned int limit_extra_subflows;
 	unsigned int add_addr_signal_max;
 	bool signal_and_subflow = false;
 	unsigned int local_addr_max;
 	struct pm_nl_pernet *pernet;
 	struct mptcp_pm_local local;
-	unsigned int subflows_max;
 
 	pernet = pm_nl_get_pernet(sock_net(sk));
 
 	add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
 	local_addr_max = mptcp_pm_get_local_addr_max(msk);
-	subflows_max = mptcp_pm_get_subflows_max(msk);
+	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	/* do lazy endpoint usage accounting for the MPC subflows */
 	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
@@ -313,7 +313,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	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,
-		 msk->pm.extra_subflows, subflows_max);
+		 msk->pm.extra_subflows, limit_extra_subflows);
 
 	/* check first for announce */
 	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
@@ -353,7 +353,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 subflow:
 	/* check if should create a new subflow */
 	while (msk->pm.local_addr_used < local_addr_max &&
-	       msk->pm.extra_subflows < subflows_max) {
+	       msk->pm.extra_subflows < limit_extra_subflows) {
 		struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 		bool fullmesh;
 		int i, nr;
@@ -402,14 +402,15 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 				  bool c_flag_case)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
-	unsigned int subflows_max = mptcp_pm_get_subflows_max(msk);
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
+	unsigned int limit_extra_subflows;
 	struct mptcp_addr_info mpc_addr;
 	struct mptcp_pm_local *local;
 	int i = 0;
 
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
@@ -444,7 +445,7 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 		msk->pm.extra_subflows++;
 		i++;
 
-		if (msk->pm.extra_subflows >= subflows_max)
+		if (msk->pm.extra_subflows >= limit_extra_subflows)
 			break;
 	}
 	rcu_read_unlock();
@@ -459,13 +460,14 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 {
 	unsigned int local_addr_max = mptcp_pm_get_local_addr_max(msk);
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
-	unsigned int subflows_max = mptcp_pm_get_subflows_max(msk);
 	struct sock *sk = (struct sock *)msk;
+	unsigned int limit_extra_subflows;
 	struct mptcp_addr_info mpc_addr;
 	struct mptcp_pm_local *local;
 	int i = 0;
 
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	while (msk->pm.local_addr_used < local_addr_max) {
 		local = &locals[i];
@@ -486,7 +488,7 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 		msk->pm.extra_subflows++;
 		i++;
 
-		if (msk->pm.extra_subflows >= subflows_max)
+		if (msk->pm.extra_subflows >= limit_extra_subflows)
 			break;
 	}
 
@@ -544,14 +546,14 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_local locals[MPTCP_PM_ADDR_MAX];
 	struct sock *sk = (struct sock *)msk;
+	unsigned int limit_extra_subflows;
 	unsigned int add_addr_accept_max;
 	struct mptcp_addr_info remote;
-	unsigned int subflows_max;
 	bool sf_created = false;
 	int i, nr;
 
 	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
-	subflows_max = mptcp_pm_get_subflows_max(msk);
+	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	pr_debug("accepted %d:%d remote family %d\n",
 		 msk->pm.add_addr_accepted, add_addr_accept_max,
@@ -586,7 +588,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 		if (remote.id)
 			msk->pm.add_addr_accepted++;
 		if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
-		    msk->pm.extra_subflows >= subflows_max)
+		    msk->pm.extra_subflows >= limit_extra_subflows)
 			WRITE_ONCE(msk->pm.accept_addr, false);
 	}
 }
@@ -1285,13 +1287,13 @@ int mptcp_pm_nl_set_limits_doit(struct sk_buff *skb, struct genl_info *info)
 	if (ret)
 		goto unlock;
 
-	subflows = pernet->subflows_max;
+	subflows = pernet->limit_extra_subflows;
 	ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
 	if (ret)
 		goto unlock;
 
 	WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
-	WRITE_ONCE(pernet->subflows_max, subflows);
+	WRITE_ONCE(pernet->limit_extra_subflows, subflows);
 
 unlock:
 	spin_unlock_bh(&pernet->lock);
@@ -1318,7 +1320,7 @@ int mptcp_pm_nl_get_limits_doit(struct sk_buff *skb, struct genl_info *info)
 		goto fail;
 
 	if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
-			READ_ONCE(pernet->subflows_max)))
+			READ_ONCE(pernet->limit_extra_subflows)))
 		goto fail;
 
 	genlmsg_end(msg, reply);
@@ -1427,7 +1429,7 @@ bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	if (msk->pm.extra_subflows == mptcp_pm_get_subflows_max(msk) ||
+	if (msk->pm.extra_subflows == mptcp_pm_get_limit_extra_subflows(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);
@@ -1462,7 +1464,7 @@ static int __net_init pm_nl_init_net(struct net *net)
 	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
 
 	/* Cit. 2 subflows ought to be enough for anybody. */
-	pernet->subflows_max = 2;
+	pernet->limit_extra_subflows = 2;
 	pernet->next_id = 1;
 	pernet->stale_loss_cnt = 4;
 	spin_lock_init(&pernet->lock);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index ca68f9a7580149e43139ec6cc61a1e0b966e7a22..4c777f87b0497ed623f0d51bf1f87cfa011cf0eb 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1182,13 +1182,13 @@ void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
+unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
 
 /* called under PM lock */
 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
 {
-	if (--msk->pm.extra_subflows < mptcp_pm_get_subflows_max(msk))
+	if (--msk->pm.extra_subflows < mptcp_pm_get_limit_extra_subflows(msk))
 		WRITE_ONCE(msk->pm.accept_subflow, true);
 }
 
@@ -1204,7 +1204,7 @@ static inline bool mptcp_pm_add_addr_c_flag_case(struct mptcp_sock *msk)
 	return READ_ONCE(msk->pm.remote_deny_join_id0) &&
 	       msk->pm.local_addr_used == 0 &&
 	       mptcp_pm_get_add_addr_accept_max(msk) == 0 &&
-	       msk->pm.extra_subflows < mptcp_pm_get_subflows_max(msk);
+	       msk->pm.extra_subflows < mptcp_pm_get_limit_extra_subflows(msk);
 }
 
 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 17966da80239d731de925f3e4211b3ee00f802e4..4e82bcfcd34e3a1dffb05799cf181ee2940e75d7 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -972,8 +972,8 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 
 	/* The following limits only make sense for the in-kernel PM */
 	if (mptcp_pm_is_kernel(msk)) {
-		info->mptcpi_subflows_max =
-			mptcp_pm_get_subflows_max(msk);
+		info->mptcpi_limit_extra_subflows =
+			mptcp_pm_get_limit_extra_subflows(msk);
 		info->mptcpi_add_addr_signal_max =
 			mptcp_pm_get_add_addr_signal_max(msk);
 		info->mptcpi_add_addr_accepted_max =

-- 
2.51.0

[PATCH net-next 07/15] mptcp: pm: in-kernel: rename 'add_addr_signal_max' to 'endp_signal_max'

[Matthieu Baerts (NGI0)]

A few variables linked to the in-kernel Path-Manager are confusing, and
it would help current and future developers, to clarify them.

One of them is 'add_addr_signal_max', which in fact represents the
maximum number of 'signal' endpoints that can be used to announced
addresses, and not the number of ADD_ADDR that can be signalled.

While at it, add an additional name for the corresponding variable in
MPTCP INFO: mptcpi_endp_signal_max. Not to break the current uAPI, the
new name is added as a 'define' pointing to the former name. This will
then also help userspace devs.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 include/uapi/linux/mptcp.h |  1 +
 net/mptcp/pm.c             |  2 +-
 net/mptcp/pm_kernel.c      | 26 +++++++++++++-------------
 net/mptcp/protocol.h       |  2 +-
 net/mptcp/sockopt.c        |  4 ++--
 5 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 314200c61f150da445ff87debb154bfd98f324fc..69fc20db1c2f731d5f93cfee4e58a23119ff7a97 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -48,6 +48,7 @@ struct mptcp_info {
 	__u8	mptcpi_subflows_max;
 	#define mptcpi_limit_extra_subflows mptcpi_subflows_max
 	__u8	mptcpi_add_addr_signal_max;
+	#define mptcpi_endp_signal_max mptcpi_add_addr_signal_max
 	__u8	mptcpi_add_addr_accepted_max;
 	__u32	mptcpi_flags;
 	__u32	mptcpi_token;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 502f6c235e06c3f6fdca9dcf3a1d7b8e97fb9df6..1100ba8b1ce8243de46b161fb27272c360559bc3 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -1037,7 +1037,7 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 		WRITE_ONCE(pm->work_pending,
 			   (!!mptcp_pm_get_local_addr_max(msk) &&
 			    subflows_allowed) ||
-			   !!mptcp_pm_get_add_addr_signal_max(msk));
+			   !!mptcp_pm_get_endp_signal_max(msk));
 		WRITE_ONCE(pm->accept_addr,
 			   !!mptcp_pm_get_add_addr_accept_max(msk) &&
 			   subflows_allowed);
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index db0d254d0e6b903fd8b920eb4cda628a811f7d58..740f0b20b941fc457831f3394c187159e9a244e8 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -20,7 +20,7 @@ struct pm_nl_pernet {
 	struct list_head	local_addr_list;
 	unsigned int		addrs;
 	unsigned int		stale_loss_cnt;
-	unsigned int		add_addr_signal_max;
+	unsigned int		endp_signal_max;
 	unsigned int		add_addr_accept_max;
 	unsigned int		local_addr_max;
 	unsigned int		limit_extra_subflows;
@@ -46,13 +46,13 @@ static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
 	return pm_nl_get_pernet(genl_info_net(info));
 }
 
-unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 {
 	const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	return READ_ONCE(pernet->add_addr_signal_max);
+	return READ_ONCE(pernet->endp_signal_max);
 }
-EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
+EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_signal_max);
 
 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
 {
@@ -275,15 +275,15 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
 	struct sock *sk = (struct sock *)msk;
 	unsigned int limit_extra_subflows;
-	unsigned int add_addr_signal_max;
 	bool signal_and_subflow = false;
+	unsigned int endp_signal_max;
 	unsigned int local_addr_max;
 	struct pm_nl_pernet *pernet;
 	struct mptcp_pm_local local;
 
 	pernet = pm_nl_get_pernet(sock_net(sk));
 
-	add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
+	endp_signal_max = mptcp_pm_get_endp_signal_max(msk);
 	local_addr_max = mptcp_pm_get_local_addr_max(msk);
 	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
@@ -312,11 +312,11 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 
 	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,
+		 msk->pm.add_addr_signaled, endp_signal_max,
 		 msk->pm.extra_subflows, limit_extra_subflows);
 
 	/* check first for announce */
-	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
+	if (msk->pm.add_addr_signaled < endp_signal_max) {
 		/* due to racing events on both ends we can reach here while
 		 * previous add address is still running: if we invoke now
 		 * mptcp_pm_announce_addr(), that will fail and the
@@ -699,8 +699,8 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		pernet->next_id = entry->addr.id;
 
 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
-		addr_max = pernet->add_addr_signal_max;
-		WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1);
+		addr_max = pernet->endp_signal_max;
+		WRITE_ONCE(pernet->endp_signal_max, addr_max + 1);
 	}
 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
 		addr_max = pernet->local_addr_max;
@@ -1098,8 +1098,8 @@ int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
 		return -EINVAL;
 	}
 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
-		addr_max = pernet->add_addr_signal_max;
-		WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1);
+		addr_max = pernet->endp_signal_max;
+		WRITE_ONCE(pernet->endp_signal_max, addr_max - 1);
 	}
 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
 		addr_max = pernet->local_addr_max;
@@ -1185,7 +1185,7 @@ static void __flush_addrs(struct list_head *list)
 
 static void __reset_counters(struct pm_nl_pernet *pernet)
 {
-	WRITE_ONCE(pernet->add_addr_signal_max, 0);
+	WRITE_ONCE(pernet->endp_signal_max, 0);
 	WRITE_ONCE(pernet->local_addr_max, 0);
 	pernet->addrs = 0;
 }
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 4c777f87b0497ed623f0d51bf1f87cfa011cf0eb..86c30cd6c1f2ceccba9d14ddac7e6334dd46e21b 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1180,7 +1180,7 @@ void __init mptcp_pm_userspace_register(void);
 void __init mptcp_pm_nl_init(void);
 void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
+unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 4e82bcfcd34e3a1dffb05799cf181ee2940e75d7..4688e0f25d15d9363b33bdcf3ad75c8295a810e3 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -974,8 +974,8 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	if (mptcp_pm_is_kernel(msk)) {
 		info->mptcpi_limit_extra_subflows =
 			mptcp_pm_get_limit_extra_subflows(msk);
-		info->mptcpi_add_addr_signal_max =
-			mptcp_pm_get_add_addr_signal_max(msk);
+		info->mptcpi_endp_signal_max =
+			mptcp_pm_get_endp_signal_max(msk);
 		info->mptcpi_add_addr_accepted_max =
 			mptcp_pm_get_add_addr_accept_max(msk);
 		info->mptcpi_local_addr_max =

-- 
2.51.0

[PATCH net-next 08/15] mptcp: pm: in-kernel: rename 'add_addr_accept_max' to 'limit_add_addr_accepted'

[Matthieu Baerts (NGI0)]

A few variables linked to the in-kernel Path-Manager are confusing, and
it would help current and future developers, to clarify them.

One of them is 'add_addr_accept_max', which in fact represents the limit
of ADD_ADDR that can be accepted:  the limit set via 'ip mptcp limit
add_addr_accepted X' for example. It is not linked to the maximum number
of accepted ADD_ADDR.

While at it, add an additional name for the corresponding variable in
MPTCP INFO: mptcpi_limit_add_addr_accepted. Not to break the current
uAPI, the new name is added as a 'define' pointing to the former name.
This will then also help userspace devs.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 include/uapi/linux/mptcp.h |  1 +
 net/mptcp/pm.c             |  2 +-
 net/mptcp/pm_kernel.c      | 27 +++++++++++++++------------
 net/mptcp/protocol.h       |  4 ++--
 net/mptcp/sockopt.c        |  4 ++--
 5 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 69fc20db1c2f731d5f93cfee4e58a23119ff7a97..1c275ce96b524cf1525b80967f28b57a59c24a0f 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -50,6 +50,7 @@ struct mptcp_info {
 	__u8	mptcpi_add_addr_signal_max;
 	#define mptcpi_endp_signal_max mptcpi_add_addr_signal_max
 	__u8	mptcpi_add_addr_accepted_max;
+	#define mptcpi_limit_add_addr_accepted mptcpi_add_addr_accepted_max
 	__u32	mptcpi_flags;
 	__u32	mptcpi_token;
 	__u64	mptcpi_write_seq;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 1100ba8b1ce8243de46b161fb27272c360559bc3..e13bfec50ef8403e7a446f5e008683a718c7176f 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -1039,7 +1039,7 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 			    subflows_allowed) ||
 			   !!mptcp_pm_get_endp_signal_max(msk));
 		WRITE_ONCE(pm->accept_addr,
-			   !!mptcp_pm_get_add_addr_accept_max(msk) &&
+			   !!mptcp_pm_get_limit_add_addr_accepted(msk) &&
 			   subflows_allowed);
 		WRITE_ONCE(pm->accept_subflow, subflows_allowed);
 
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 740f0b20b941fc457831f3394c187159e9a244e8..92f7419485a82908f55563716b9c6e57f49b716b 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -21,7 +21,7 @@ struct pm_nl_pernet {
 	unsigned int		addrs;
 	unsigned int		stale_loss_cnt;
 	unsigned int		endp_signal_max;
-	unsigned int		add_addr_accept_max;
+	unsigned int		limit_add_addr_accepted;
 	unsigned int		local_addr_max;
 	unsigned int		limit_extra_subflows;
 	unsigned int		next_id;
@@ -54,13 +54,13 @@ unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_signal_max);
 
-unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	return READ_ONCE(pernet->add_addr_accept_max);
+	return READ_ONCE(pernet->limit_add_addr_accepted);
 }
-EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
+EXPORT_SYMBOL_GPL(mptcp_pm_get_limit_add_addr_accepted);
 
 unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
 {
@@ -547,16 +547,16 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 	struct mptcp_pm_local locals[MPTCP_PM_ADDR_MAX];
 	struct sock *sk = (struct sock *)msk;
 	unsigned int limit_extra_subflows;
-	unsigned int add_addr_accept_max;
+	unsigned int limit_add_addr_accepted;
 	struct mptcp_addr_info remote;
 	bool sf_created = false;
 	int i, nr;
 
-	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
+	limit_add_addr_accepted = mptcp_pm_get_limit_add_addr_accepted(msk);
 	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	pr_debug("accepted %d:%d remote family %d\n",
-		 msk->pm.add_addr_accepted, add_addr_accept_max,
+		 msk->pm.add_addr_accepted, limit_add_addr_accepted,
 		 msk->pm.remote.family);
 
 	remote = msk->pm.remote;
@@ -587,7 +587,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 		/* add_addr_accepted is not decr for ID 0 */
 		if (remote.id)
 			msk->pm.add_addr_accepted++;
-		if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
+		if (msk->pm.add_addr_accepted >= limit_add_addr_accepted ||
 		    msk->pm.extra_subflows >= limit_extra_subflows)
 			WRITE_ONCE(msk->pm.accept_addr, false);
 	}
@@ -596,10 +596,13 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 void mptcp_pm_nl_rm_addr(struct mptcp_sock *msk, u8 rm_id)
 {
 	if (rm_id && WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
+		unsigned int limit_add_addr_accepted =
+			mptcp_pm_get_limit_add_addr_accepted(msk);
+
 		/* Note: if the subflow has been closed before, this
 		 * add_addr_accepted counter will not be decremented.
 		 */
-		if (--msk->pm.add_addr_accepted < mptcp_pm_get_add_addr_accept_max(msk))
+		if (--msk->pm.add_addr_accepted < limit_add_addr_accepted)
 			WRITE_ONCE(msk->pm.accept_addr, true);
 	}
 }
@@ -1282,7 +1285,7 @@ int mptcp_pm_nl_set_limits_doit(struct sk_buff *skb, struct genl_info *info)
 	int ret;
 
 	spin_lock_bh(&pernet->lock);
-	rcv_addrs = pernet->add_addr_accept_max;
+	rcv_addrs = pernet->limit_add_addr_accepted;
 	ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
 	if (ret)
 		goto unlock;
@@ -1292,7 +1295,7 @@ int mptcp_pm_nl_set_limits_doit(struct sk_buff *skb, struct genl_info *info)
 	if (ret)
 		goto unlock;
 
-	WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
+	WRITE_ONCE(pernet->limit_add_addr_accepted, rcv_addrs);
 	WRITE_ONCE(pernet->limit_extra_subflows, subflows);
 
 unlock:
@@ -1316,7 +1319,7 @@ int mptcp_pm_nl_get_limits_doit(struct sk_buff *skb, struct genl_info *info)
 		goto fail;
 
 	if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
-			READ_ONCE(pernet->add_addr_accept_max)))
+			READ_ONCE(pernet->limit_add_addr_accepted)))
 		goto fail;
 
 	if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 86c30cd6c1f2ceccba9d14ddac7e6334dd46e21b..114995e1352d02c3e0bcb29ccffcc1ac413be191 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1181,7 +1181,7 @@ void __init mptcp_pm_nl_init(void);
 void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
+unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
 
@@ -1203,7 +1203,7 @@ static inline bool mptcp_pm_add_addr_c_flag_case(struct mptcp_sock *msk)
 {
 	return READ_ONCE(msk->pm.remote_deny_join_id0) &&
 	       msk->pm.local_addr_used == 0 &&
-	       mptcp_pm_get_add_addr_accept_max(msk) == 0 &&
+	       mptcp_pm_get_limit_add_addr_accepted(msk) == 0 &&
 	       msk->pm.extra_subflows < mptcp_pm_get_limit_extra_subflows(msk);
 }
 
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 4688e0f25d15d9363b33bdcf3ad75c8295a810e3..5ab9909dbe799bed5c59d2b1b04cc0e88e960574 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -976,8 +976,8 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 			mptcp_pm_get_limit_extra_subflows(msk);
 		info->mptcpi_endp_signal_max =
 			mptcp_pm_get_endp_signal_max(msk);
-		info->mptcpi_add_addr_accepted_max =
-			mptcp_pm_get_add_addr_accept_max(msk);
+		info->mptcpi_limit_add_addr_accepted =
+			mptcp_pm_get_limit_add_addr_accepted(msk);
 		info->mptcpi_local_addr_max =
 			mptcp_pm_get_local_addr_max(msk);
 	}

-- 
2.51.0

[PATCH net-next 09/15] mptcp: pm: in-kernel: rename 'local_addr_max' to 'endp_subflow_max'

[Matthieu Baerts (NGI0)]

A few variables linked to the in-kernel Path-Manager are confusing, and
it would help current and future developers, to clarify them.

One of them is 'local_addr_max', which in fact represents the maximum
number of 'subflow' endpoints that can be used to create new subflows,
and not the number of local addresses that have been used to create
subflows.

While at it, add an additional name for the corresponding variable in
MPTCP INFO: mptcpi_endp_subflow_max. Not to break the current uAPI, the
new name is added as a 'define' pointing to the former name. This will
then also help userspace devs.

Also move the variable and function next to the other 'endp_X_max' ones.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 include/uapi/linux/mptcp.h |  1 +
 net/mptcp/pm.c             |  2 +-
 net/mptcp/pm_kernel.c      | 40 ++++++++++++++++++++--------------------
 net/mptcp/protocol.h       |  2 +-
 net/mptcp/sockopt.c        |  4 ++--
 5 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 1c275ce96b524cf1525b80967f28b57a59c24a0f..5ec996977b3fa2351222e6d01b814770b34348e9 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -58,6 +58,7 @@ struct mptcp_info {
 	__u64	mptcpi_rcv_nxt;
 	__u8	mptcpi_local_addr_used;
 	__u8	mptcpi_local_addr_max;
+	#define mptcpi_endp_subflow_max mptcpi_local_addr_max
 	__u8	mptcpi_csum_enabled;
 	__u32	mptcpi_retransmits;
 	__u64	mptcpi_bytes_retrans;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index e13bfec50ef8403e7a446f5e008683a718c7176f..2ff1b949956834aa5c78a1fcb40087aed43225ef 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -1035,7 +1035,7 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 		 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
 		 */
 		WRITE_ONCE(pm->work_pending,
-			   (!!mptcp_pm_get_local_addr_max(msk) &&
+			   (!!mptcp_pm_get_endp_subflow_max(msk) &&
 			    subflows_allowed) ||
 			   !!mptcp_pm_get_endp_signal_max(msk));
 		WRITE_ONCE(pm->accept_addr,
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 92f7419485a82908f55563716b9c6e57f49b716b..e62e21eb9da12a7b361049efce1ba193fcbdc572 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -21,8 +21,8 @@ struct pm_nl_pernet {
 	unsigned int		addrs;
 	unsigned int		stale_loss_cnt;
 	unsigned int		endp_signal_max;
+	unsigned int		endp_subflow_max;
 	unsigned int		limit_add_addr_accepted;
-	unsigned int		local_addr_max;
 	unsigned int		limit_extra_subflows;
 	unsigned int		next_id;
 	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
@@ -54,6 +54,14 @@ unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_signal_max);
 
+unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	return READ_ONCE(pernet->endp_subflow_max);
+}
+EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_subflow_max);
+
 unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
@@ -70,14 +78,6 @@ unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_limit_extra_subflows);
 
-unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
-{
-	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
-
-	return READ_ONCE(pernet->local_addr_max);
-}
-EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max);
-
 static bool lookup_subflow_by_daddr(const struct list_head *list,
 				    const struct mptcp_addr_info *daddr)
 {
@@ -276,15 +276,15 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	struct sock *sk = (struct sock *)msk;
 	unsigned int limit_extra_subflows;
 	bool signal_and_subflow = false;
+	unsigned int endp_subflow_max;
 	unsigned int endp_signal_max;
-	unsigned int local_addr_max;
 	struct pm_nl_pernet *pernet;
 	struct mptcp_pm_local local;
 
 	pernet = pm_nl_get_pernet(sock_net(sk));
 
 	endp_signal_max = mptcp_pm_get_endp_signal_max(msk);
-	local_addr_max = mptcp_pm_get_local_addr_max(msk);
+	endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
 	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	/* do lazy endpoint usage accounting for the MPC subflows */
@@ -311,7 +311,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	}
 
 	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
-		 msk->pm.local_addr_used, local_addr_max,
+		 msk->pm.local_addr_used, endp_subflow_max,
 		 msk->pm.add_addr_signaled, endp_signal_max,
 		 msk->pm.extra_subflows, limit_extra_subflows);
 
@@ -352,7 +352,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 
 subflow:
 	/* check if should create a new subflow */
-	while (msk->pm.local_addr_used < local_addr_max &&
+	while (msk->pm.local_addr_used < endp_subflow_max &&
 	       msk->pm.extra_subflows < limit_extra_subflows) {
 		struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 		bool fullmesh;
@@ -458,7 +458,7 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 				struct mptcp_addr_info *remote,
 				struct mptcp_pm_local *locals)
 {
-	unsigned int local_addr_max = mptcp_pm_get_local_addr_max(msk);
+	unsigned int endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 	struct sock *sk = (struct sock *)msk;
 	unsigned int limit_extra_subflows;
@@ -469,7 +469,7 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
 	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
-	while (msk->pm.local_addr_used < local_addr_max) {
+	while (msk->pm.local_addr_used < endp_subflow_max) {
 		local = &locals[i];
 
 		if (!select_local_address(pernet, msk, local))
@@ -706,8 +706,8 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		WRITE_ONCE(pernet->endp_signal_max, addr_max + 1);
 	}
 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
-		addr_max = pernet->local_addr_max;
-		WRITE_ONCE(pernet->local_addr_max, addr_max + 1);
+		addr_max = pernet->endp_subflow_max;
+		WRITE_ONCE(pernet->endp_subflow_max, addr_max + 1);
 	}
 
 	pernet->addrs++;
@@ -1105,8 +1105,8 @@ int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
 		WRITE_ONCE(pernet->endp_signal_max, addr_max - 1);
 	}
 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
-		addr_max = pernet->local_addr_max;
-		WRITE_ONCE(pernet->local_addr_max, addr_max - 1);
+		addr_max = pernet->endp_subflow_max;
+		WRITE_ONCE(pernet->endp_subflow_max, addr_max - 1);
 	}
 
 	pernet->addrs--;
@@ -1189,7 +1189,7 @@ static void __flush_addrs(struct list_head *list)
 static void __reset_counters(struct pm_nl_pernet *pernet)
 {
 	WRITE_ONCE(pernet->endp_signal_max, 0);
-	WRITE_ONCE(pernet->local_addr_max, 0);
+	WRITE_ONCE(pernet->endp_subflow_max, 0);
 	pernet->addrs = 0;
 }
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 114995e1352d02c3e0bcb29ccffcc1ac413be191..df8f977039d0a716e5792e3ada7eee9e075f1581 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1181,9 +1181,9 @@ void __init mptcp_pm_nl_init(void);
 void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
+unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
 
 /* called under PM lock */
 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 5ab9909dbe799bed5c59d2b1b04cc0e88e960574..92a2a274262732a345b9ab185efd7da1f0a5773a 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -978,8 +978,8 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 			mptcp_pm_get_endp_signal_max(msk);
 		info->mptcpi_limit_add_addr_accepted =
 			mptcp_pm_get_limit_add_addr_accepted(msk);
-		info->mptcpi_local_addr_max =
-			mptcp_pm_get_local_addr_max(msk);
+		info->mptcpi_endp_subflow_max =
+			mptcp_pm_get_endp_subflow_max(msk);
 	}
 
 	if (__mptcp_check_fallback(msk))

-- 
2.51.0

[PATCH net-next 10/15] mptcp: pm: in-kernel: rename 'local_addr_list' to 'endp_list'

[Matthieu Baerts (NGI0)]

A few variables linked to the in-kernel Path-Manager are confusing, and
it would help current and future developers, to clarify them.

One of them is 'local_addr_list', which in fact represents the list of
endpoints, and not only the 'subflow' endpoints.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index e62e21eb9da12a7b361049efce1ba193fcbdc572..056624965546dac7e087c82c9df8c496c8959f33 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -17,7 +17,7 @@ static int pm_nl_pernet_id;
 struct pm_nl_pernet {
 	/* protects pernet updates */
 	spinlock_t		lock;
-	struct list_head	local_addr_list;
+	struct list_head	endp_list;
 	unsigned int		addrs;
 	unsigned int		stale_loss_cnt;
 	unsigned int		endp_signal_max;
@@ -110,7 +110,7 @@ select_local_address(const struct pm_nl_pernet *pernet,
 	msk_owned_by_me(msk);
 
 	rcu_read_lock();
-	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+	list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 			continue;
 
@@ -141,7 +141,7 @@ select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
 	 * Note: removal from the local address list during the msk life-cycle
 	 * can lead to additional addresses not being announced.
 	 */
-	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+	list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
 		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 			continue;
 
@@ -250,7 +250,7 @@ __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 {
 	struct mptcp_pm_addr_entry *entry;
 
-	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,
+	list_for_each_entry_rcu(entry, &pernet->endp_list, list,
 				lockdep_is_held(&pernet->lock)) {
 		if (entry->addr.id == id)
 			return entry;
@@ -263,7 +263,7 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
 {
 	struct mptcp_pm_addr_entry *entry;
 
-	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,
+	list_for_each_entry_rcu(entry, &pernet->endp_list, list,
 				lockdep_is_held(&pernet->lock)) {
 		if (mptcp_addresses_equal(&entry->addr, info, entry->addr.port))
 			return entry;
@@ -413,7 +413,7 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	rcu_read_lock();
-	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+	list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
 		bool is_id0;
 
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
@@ -650,7 +650,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 	 */
 	if (!address_use_port(entry))
 		entry->addr.port = 0;
-	list_for_each_entry(cur, &pernet->local_addr_list, list) {
+	list_for_each_entry(cur, &pernet->endp_list, list) {
 		if (mptcp_addresses_equal(&cur->addr, &entry->addr,
 					  cur->addr.port || entry->addr.port)) {
 			/* allow replacing the exiting endpoint only if such
@@ -712,9 +712,9 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 
 	pernet->addrs++;
 	if (!entry->addr.port)
-		list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
+		list_add_tail_rcu(&entry->list, &pernet->endp_list);
 	else
-		list_add_rcu(&entry->list, &pernet->local_addr_list);
+		list_add_rcu(&entry->list, &pernet->endp_list);
 	ret = entry->addr.id;
 
 out:
@@ -1199,7 +1199,7 @@ int mptcp_pm_nl_flush_addrs_doit(struct sk_buff *skb, struct genl_info *info)
 	LIST_HEAD(free_list);
 
 	spin_lock_bh(&pernet->lock);
-	list_splice_init(&pernet->local_addr_list, &free_list);
+	list_splice_init(&pernet->endp_list, &free_list);
 	__reset_counters(pernet);
 	pernet->next_id = 1;
 	bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
@@ -1464,7 +1464,7 @@ static int __net_init pm_nl_init_net(struct net *net)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
 
-	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
+	INIT_LIST_HEAD_RCU(&pernet->endp_list);
 
 	/* Cit. 2 subflows ought to be enough for anybody. */
 	pernet->limit_extra_subflows = 2;
@@ -1490,7 +1490,7 @@ static void __net_exit pm_nl_exit_net(struct list_head *net_list)
 		 * other modifiers, also netns core already waited for a
 		 * RCU grace period.
 		 */
-		__flush_addrs(&pernet->local_addr_list);
+		__flush_addrs(&pernet->endp_list);
 	}
 }
 

-- 
2.51.0

[PATCH net-next 11/15] mptcp: pm: in-kernel: rename 'addrs' to 'endpoints'

[Matthieu Baerts (NGI0)]

A few variables linked to the in-kernel Path-Manager are confusing, and
it would help current and future developers, to clarify them.

One of them is 'addrs', which in fact represents the number of declared
endpoints, and not only the 'signal' endpoints.

No functional changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 056624965546dac7e087c82c9df8c496c8959f33..d30b06605f623aaaf38152ab6750841c5deeb0b5 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -18,7 +18,7 @@ struct pm_nl_pernet {
 	/* protects pernet updates */
 	spinlock_t		lock;
 	struct list_head	endp_list;
-	unsigned int		addrs;
+	unsigned int		endpoints;
 	unsigned int		stale_loss_cnt;
 	unsigned int		endp_signal_max;
 	unsigned int		endp_subflow_max;
@@ -636,7 +636,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 	 */
 	if (pernet->next_id == MPTCP_PM_MAX_ADDR_ID)
 		pernet->next_id = 1;
-	if (pernet->addrs >= MPTCP_PM_ADDR_MAX) {
+	if (pernet->endpoints >= MPTCP_PM_ADDR_MAX) {
 		ret = -ERANGE;
 		goto out;
 	}
@@ -675,7 +675,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 				goto out;
 			}
 
-			pernet->addrs--;
+			pernet->endpoints--;
 			entry->addr.id = cur->addr.id;
 			list_del_rcu(&cur->list);
 			del_entry = cur;
@@ -710,7 +710,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		WRITE_ONCE(pernet->endp_subflow_max, addr_max + 1);
 	}
 
-	pernet->addrs++;
+	pernet->endpoints++;
 	if (!entry->addr.port)
 		list_add_tail_rcu(&entry->list, &pernet->endp_list);
 	else
@@ -1109,7 +1109,7 @@ int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
 		WRITE_ONCE(pernet->endp_subflow_max, addr_max - 1);
 	}
 
-	pernet->addrs--;
+	pernet->endpoints--;
 	list_del_rcu(&entry->list);
 	__clear_bit(entry->addr.id, pernet->id_bitmap);
 	spin_unlock_bh(&pernet->lock);
@@ -1190,7 +1190,7 @@ static void __reset_counters(struct pm_nl_pernet *pernet)
 {
 	WRITE_ONCE(pernet->endp_signal_max, 0);
 	WRITE_ONCE(pernet->endp_subflow_max, 0);
-	pernet->addrs = 0;
+	pernet->endpoints = 0;
 }
 
 int mptcp_pm_nl_flush_addrs_doit(struct sk_buff *skb, struct genl_info *info)

-- 
2.51.0

[PATCH net-next 12/15] mptcp: pm: in-kernel: remove stale_loss_cnt

[Matthieu Baerts (NGI0)]

It is currently not used.

It was in fact never used since its introduction in commit ff5a0b421cb2
("mptcp: faster active backup recovery"). It was probably initially
added to struct pm_nl_pernet during the development of this commit,
before being added to struct mptcp_pernet in ctrl.c, but not removed
from the first place.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index d30b06605f623aaaf38152ab6750841c5deeb0b5..0e1e99e72950f2432b33610047bc4aa68c5e75af 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -19,7 +19,6 @@ struct pm_nl_pernet {
 	spinlock_t		lock;
 	struct list_head	endp_list;
 	unsigned int		endpoints;
-	unsigned int		stale_loss_cnt;
 	unsigned int		endp_signal_max;
 	unsigned int		endp_subflow_max;
 	unsigned int		limit_add_addr_accepted;
@@ -1469,7 +1468,6 @@ static int __net_init pm_nl_init_net(struct net *net)
 	/* Cit. 2 subflows ought to be enough for anybody. */
 	pernet->limit_extra_subflows = 2;
 	pernet->next_id = 1;
-	pernet->stale_loss_cnt = 4;
 	spin_lock_init(&pernet->lock);
 
 	/* No need to initialize other pernet fields, the struct is zeroed at

-- 
2.51.0

[PATCH net-next 13/15] mptcp: pm: in-kernel: reduce pernet struct size

[Matthieu Baerts (NGI0)]

All the 'unsigned int' variables from the 'pm_nl_pernet' structure are
bounded to MPTCP_PM_ADDR_MAX, currently set to 8. The endpoint ID is
also bounded by the protocol to 8-bit. MPTCP_PM_ADDR_MAX, if extended
later, will never over 8-bit.

So no need to use 'unsigned int' variables, 'u8' is enough.

Note that the exposed counters in MPTCP_INFO are already limited to
8-bit, same for pm->extra_subflows, and others. So it seems even better
to limit them to 8-bit.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 59 ++++++++++++++++++++-------------------------------
 net/mptcp/protocol.h  |  8 +++----
 2 files changed, 27 insertions(+), 40 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 0e1e99e72950f2432b33610047bc4aa68c5e75af..117f842fe18e44f6e887d9044c7b0bb55cbb9084 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -18,12 +18,12 @@ struct pm_nl_pernet {
 	/* protects pernet updates */
 	spinlock_t		lock;
 	struct list_head	endp_list;
-	unsigned int		endpoints;
-	unsigned int		endp_signal_max;
-	unsigned int		endp_subflow_max;
-	unsigned int		limit_add_addr_accepted;
-	unsigned int		limit_extra_subflows;
-	unsigned int		next_id;
+	u8			endpoints;
+	u8			endp_signal_max;
+	u8			endp_subflow_max;
+	u8			limit_add_addr_accepted;
+	u8			limit_extra_subflows;
+	u8			next_id;
 	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
 };
 
@@ -45,7 +45,7 @@ static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
 	return pm_nl_get_pernet(genl_info_net(info));
 }
 
-unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 {
 	const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -53,7 +53,7 @@ unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_signal_max);
 
-unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -61,7 +61,7 @@ unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_subflow_max);
 
-unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -69,7 +69,7 @@ unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_limit_add_addr_accepted);
 
-unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -185,15 +185,13 @@ fill_remote_addresses_fullmesh(struct mptcp_sock *msk,
 			       struct mptcp_addr_info *local,
 			       struct mptcp_addr_info *addrs)
 {
+	u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
 	DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
 	struct sock *sk = (struct sock *)msk, *ssk;
 	struct mptcp_subflow_context *subflow;
-	unsigned int limit_extra_subflows;
 	int i = 0;
 
-	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
-
 	/* Forbid creation of new subflows matching existing ones, possibly
 	 * already created by incoming ADD_ADDR
 	 */
@@ -272,20 +270,14 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
 
 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
+	u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	u8 endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
+	u8 endp_signal_max = mptcp_pm_get_endp_signal_max(msk);
 	struct sock *sk = (struct sock *)msk;
-	unsigned int limit_extra_subflows;
 	bool signal_and_subflow = false;
-	unsigned int endp_subflow_max;
-	unsigned int endp_signal_max;
-	struct pm_nl_pernet *pernet;
 	struct mptcp_pm_local local;
 
-	pernet = pm_nl_get_pernet(sock_net(sk));
-
-	endp_signal_max = mptcp_pm_get_endp_signal_max(msk);
-	endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
-	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(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_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
@@ -400,16 +392,15 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 				  struct mptcp_pm_local *locals,
 				  bool c_flag_case)
 {
+	u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
-	unsigned int limit_extra_subflows;
 	struct mptcp_addr_info mpc_addr;
 	struct mptcp_pm_local *local;
 	int i = 0;
 
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
-	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
@@ -457,16 +448,15 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 				struct mptcp_addr_info *remote,
 				struct mptcp_pm_local *locals)
 {
-	unsigned int endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
+	u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	u8 endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
 	struct sock *sk = (struct sock *)msk;
-	unsigned int limit_extra_subflows;
 	struct mptcp_addr_info mpc_addr;
 	struct mptcp_pm_local *local;
 	int i = 0;
 
 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
-	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
 	while (msk->pm.local_addr_used < endp_subflow_max) {
 		local = &locals[i];
@@ -543,17 +533,14 @@ fill_local_addresses_vec(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
 
 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 {
+	u8 limit_add_addr_accepted = mptcp_pm_get_limit_add_addr_accepted(msk);
+	u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 	struct mptcp_pm_local locals[MPTCP_PM_ADDR_MAX];
 	struct sock *sk = (struct sock *)msk;
-	unsigned int limit_extra_subflows;
-	unsigned int limit_add_addr_accepted;
 	struct mptcp_addr_info remote;
 	bool sf_created = false;
 	int i, nr;
 
-	limit_add_addr_accepted = mptcp_pm_get_limit_add_addr_accepted(msk);
-	limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
-
 	pr_debug("accepted %d:%d remote family %d\n",
 		 msk->pm.add_addr_accepted, limit_add_addr_accepted,
 		 msk->pm.remote.family);
@@ -595,7 +582,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 void mptcp_pm_nl_rm_addr(struct mptcp_sock *msk, u8 rm_id)
 {
 	if (rm_id && WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
-		unsigned int limit_add_addr_accepted =
+		u8 limit_add_addr_accepted =
 			mptcp_pm_get_limit_add_addr_accepted(msk);
 
 		/* Note: if the subflow has been closed before, this
@@ -626,8 +613,8 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 					     bool needs_id, bool replace)
 {
 	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
-	unsigned int addr_max;
 	int ret = -EINVAL;
+	u8 addr_max;
 
 	spin_lock_bh(&pernet->lock);
 	/* to keep the code simple, don't do IDR-like allocation for address ID,
@@ -1072,8 +1059,8 @@ int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 	struct mptcp_pm_addr_entry addr, *entry;
-	unsigned int addr_max;
 	struct nlattr *attr;
+	u8 addr_max;
 	int ret;
 
 	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index df8f977039d0a716e5792e3ada7eee9e075f1581..0cd3333cafafad19a8c2c8ea302265af9f27a8bf 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1180,10 +1180,10 @@ void __init mptcp_pm_userspace_register(void);
 void __init mptcp_pm_nl_init(void);
 void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
 
 /* called under PM lock */
 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)

-- 
2.51.0

[PATCH net-next 14/15] mptcp: pm: in-kernel: compare IDs instead of addresses

[Matthieu Baerts (NGI0)]

When receiving an ADD_ADDR right after the 3WHS, the connection will
switch to 'fully established'. It means the MPTCP worker will be called
to treat two events, in this order: ADD_ADDR_RECEIVED, PM_ESTABLISHED.

The MPTCP endpoints cannot have the ID 0, because it is reserved to the
address and port used by the initial subflow. To be able to deal with
this case in different places, msk->mpc_endpoint_id contains the
endpoint ID linked to the initial subflow. This variable was only set
when treating the first PM_ESTABLISHED event, after ADD_ADDR_RECEIVED.
That's why in fill_local_addresses_vec(), the endpoint addresses were
compared with the one of the initial subflow, instead of only comparing
the IDs.

Instead, msk->mpc_endpoint_id is now set when treating ADD_ADDR_RECEIVED
as well, if needed, then the IDs can be compared.

To be able to do so, the code doing that is now in a dedicated helper,
and called from the functions linked to the two actions.

While at it, mptcp_endp_get_local_id() has also been moved up, next to
this new helper, because they are linked, and to be able to use it in
fill_local_addresses_vec() in the next commit.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_kernel.c | 82 +++++++++++++++++++++++++++------------------------
 1 file changed, 44 insertions(+), 38 deletions(-)

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 117f842fe18e44f6e887d9044c7b0bb55cbb9084..55dbf89d19b8afeb879f5307c035c855601c6b04 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -268,6 +268,46 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
 	return NULL;
 }
 
+static u8 mptcp_endp_get_local_id(struct mptcp_sock *msk,
+				  const struct mptcp_addr_info *addr)
+{
+	return msk->mpc_endpoint_id == addr->id ? 0 : addr->id;
+}
+
+/* Set mpc_endpoint_id, and send MP_PRIO for ID0 if needed */
+static void mptcp_mpc_endpoint_setup(struct mptcp_sock *msk)
+{
+	struct mptcp_subflow_context *subflow;
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_addr_info mpc_addr;
+	struct pm_nl_pernet *pernet;
+	bool backup = false;
+
+	/* do lazy endpoint usage accounting for the MPC subflows */
+	if (likely(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED)) ||
+	    !msk->first)
+		return;
+
+	subflow = mptcp_subflow_ctx(msk->first);
+	pernet = pm_nl_get_pernet_from_msk(msk);
+
+	mptcp_local_address((struct sock_common *)msk->first, &mpc_addr);
+	rcu_read_lock();
+	entry = __lookup_addr(pernet, &mpc_addr);
+	if (entry) {
+		__clear_bit(entry->addr.id, msk->pm.id_avail_bitmap);
+		msk->mpc_endpoint_id = entry->addr.id;
+		backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	}
+	rcu_read_unlock();
+
+	/* Send MP_PRIO */
+	if (backup)
+		mptcp_pm_send_ack(msk, subflow, true, backup);
+
+	msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
+}
+
 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
 	u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
@@ -278,28 +318,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	bool signal_and_subflow = false;
 	struct mptcp_pm_local local;
 
-	/* do lazy endpoint usage accounting for the MPC subflows */
-	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
-		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
-		struct mptcp_pm_addr_entry *entry;
-		struct mptcp_addr_info mpc_addr;
-		bool backup = false;
-
-		mptcp_local_address((struct sock_common *)msk->first, &mpc_addr);
-		rcu_read_lock();
-		entry = __lookup_addr(pernet, &mpc_addr);
-		if (entry) {
-			__clear_bit(entry->addr.id, msk->pm.id_avail_bitmap);
-			msk->mpc_endpoint_id = entry->addr.id;
-			backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
-		}
-		rcu_read_unlock();
-
-		if (backup)
-			mptcp_pm_send_ack(msk, subflow, true, backup);
-
-		msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
-	}
+	mptcp_mpc_endpoint_setup(msk);
 
 	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
 		 msk->pm.local_addr_used, endp_subflow_max,
@@ -396,12 +415,9 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
-	struct mptcp_addr_info mpc_addr;
 	struct mptcp_pm_local *local;
 	int i = 0;
 
-	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
-
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
 		bool is_id0;
@@ -417,8 +433,7 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 		local->flags = entry->flags;
 		local->ifindex = entry->ifindex;
 
-		is_id0 = mptcp_addresses_equal(&local->addr, &mpc_addr,
-					       local->addr.port);
+		is_id0 = local->addr.id == msk->mpc_endpoint_id;
 
 		if (c_flag_case &&
 		    (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)) {
@@ -452,12 +467,9 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 	u8 endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
 	struct sock *sk = (struct sock *)msk;
-	struct mptcp_addr_info mpc_addr;
 	struct mptcp_pm_local *local;
 	int i = 0;
 
-	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
-
 	while (msk->pm.local_addr_used < endp_subflow_max) {
 		local = &locals[i];
 
@@ -469,8 +481,7 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 		if (!mptcp_pm_addr_families_match(sk, &local->addr, remote))
 			continue;
 
-		if (mptcp_addresses_equal(&local->addr, &mpc_addr,
-					  local->addr.port))
+		if (local->addr.id == msk->mpc_endpoint_id)
 			continue;
 
 		msk->pm.local_addr_used++;
@@ -548,6 +559,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 	remote = msk->pm.remote;
 	mptcp_pm_announce_addr(msk, &remote, true);
 	mptcp_pm_addr_send_ack(msk);
+	mptcp_mpc_endpoint_setup(msk);
 
 	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
 		return;
@@ -935,12 +947,6 @@ int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
 	return ret;
 }
 
-static u8 mptcp_endp_get_local_id(struct mptcp_sock *msk,
-				  const struct mptcp_addr_info *addr)
-{
-	return msk->mpc_endpoint_id == addr->id ? 0 : addr->id;
-}
-
 static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 				      const struct mptcp_addr_info *addr,
 				      bool force)

-- 
2.51.0

[PATCH net-next 15/15] mptcp: pm: in-kernel: add laminar endpoints

[Matthieu Baerts (NGI0)]

Currently, upon the reception of an ADD_ADDR (and when the fullmesh flag
is not used), the in-kernel PM will create new subflows using the local
address the routing configuration will pick.

It would be easier to pick local addresses from a selected list of
endpoints, and use it only once, than relying on routing rules.

Use case: both the client (C) and the server (S) have two addresses (a
and b). The client establishes the connection between C(a) and S(a).
Once established, the server announces its additional address S(b). Once
received, the client connects to it using its second address C(b).
Compared to a situation without the 'laminar' endpoint for C(b), the
client didn't use this address C(b) to establish a subflow to the
server's primary address S(a). So at the end, we have:

   C        S
  C(a) --- S(a)
  C(b) --- S(b)

In case of a 3rd address on each side (C(c) and S(c)), upon the
reception of an ADD_ADDR with S(c), the client should not pick C(b)
because it has already been used. C(c) should then be used.

Note that this situation is currently possible if C doesn't add any
endpoint, but configure the routing in order to pick C(b) for the route
to S(b), and pick C(c) for the route to S(c). That doesn't sound very
practical because it means knowing in advance the IP addresses that
will be used and announced by the server.

'laminar', like the idea of laminar flows: the different subflows don't
mix with each other on an endpoint, unlike the "turbulent" way traffic
is mixed by 'fullmesh'.

In the code, the new endpoint type is added. Similar to the other
subflow types, an MPTCP_INFO counter is added. While at it, hole are now
commented in struct mptcp_info, to remember next time that these holes
can no longer be used.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/503
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 include/uapi/linux/mptcp.h |  6 +++-
 net/mptcp/pm_kernel.c      | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.h       |  1 +
 net/mptcp/sockopt.c        |  2 ++
 4 files changed, 90 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 5ec996977b3fa2351222e6d01b814770b34348e9..87cfab874e2415d88c98f17e5562b0440feafaab 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -39,6 +39,7 @@
 #define MPTCP_PM_ADDR_FLAG_BACKUP		_BITUL(2)
 #define MPTCP_PM_ADDR_FLAG_FULLMESH		_BITUL(3)
 #define MPTCP_PM_ADDR_FLAG_IMPLICIT		_BITUL(4)
+#define MPTCP_PM_ADDR_FLAG_LAMINAR		_BITUL(5)
 
 struct mptcp_info {
 	__u8	mptcpi_subflows;
@@ -51,6 +52,7 @@ struct mptcp_info {
 	#define mptcpi_endp_signal_max mptcpi_add_addr_signal_max
 	__u8	mptcpi_add_addr_accepted_max;
 	#define mptcpi_limit_add_addr_accepted mptcpi_add_addr_accepted_max
+	/* 16-bit hole that can no longer be filled */
 	__u32	mptcpi_flags;
 	__u32	mptcpi_token;
 	__u64	mptcpi_write_seq;
@@ -60,13 +62,15 @@ struct mptcp_info {
 	__u8	mptcpi_local_addr_max;
 	#define mptcpi_endp_subflow_max mptcpi_local_addr_max
 	__u8	mptcpi_csum_enabled;
+	/* 8-bit hole that can no longer be filled */
 	__u32	mptcpi_retransmits;
 	__u64	mptcpi_bytes_retrans;
 	__u64	mptcpi_bytes_sent;
 	__u64	mptcpi_bytes_received;
 	__u64	mptcpi_bytes_acked;
 	__u8	mptcpi_subflows_total;
-	__u8	reserved[3];
+	__u8	mptcpi_endp_laminar_max;
+	__u8	reserved[2];
 	__u32	mptcpi_last_data_sent;
 	__u32	mptcpi_last_data_recv;
 	__u32	mptcpi_last_ack_recv;
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 55dbf89d19b8afeb879f5307c035c855601c6b04..e0f44dc232aa54103ba7a0a685efb2fed0f43aa4 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -21,6 +21,7 @@ struct pm_nl_pernet {
 	u8			endpoints;
 	u8			endp_signal_max;
 	u8			endp_subflow_max;
+	u8			endp_laminar_max;
 	u8			limit_add_addr_accepted;
 	u8			limit_extra_subflows;
 	u8			next_id;
@@ -61,6 +62,14 @@ u8 mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_subflow_max);
 
+u8 mptcp_pm_get_endp_laminar_max(const struct mptcp_sock *msk)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	return READ_ONCE(pernet->endp_laminar_max);
+}
+EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_laminar_max);
+
 u8 mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
@@ -458,6 +467,66 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
 	return i;
 }
 
+static unsigned int
+fill_local_laminar_endp(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
+			struct mptcp_pm_local *locals)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+	struct mptcp_subflow_context *subflow;
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_pm_local *local;
+	int found = 0;
+
+	/* Forbid creation of new subflows matching existing ones, possibly
+	 * already created by 'subflow' endpoints
+	 */
+	bitmap_zero(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+	mptcp_for_each_subflow(msk, subflow) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+		if ((1 << inet_sk_state_load(ssk)) &
+		    (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING |
+		     TCPF_CLOSE))
+			continue;
+
+		__set_bit(subflow_get_local_id(subflow), unavail_id);
+	}
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_LAMINAR))
+			continue;
+
+		if (!mptcp_pm_addr_families_match(sk, &entry->addr, remote))
+			continue;
+
+		if (test_bit(mptcp_endp_get_local_id(msk, &entry->addr),
+			     unavail_id))
+			continue;
+
+		local = &locals[0];
+		local->addr = entry->addr;
+		local->flags = entry->flags;
+		local->ifindex = entry->ifindex;
+
+		if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
+			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+
+			if (local->addr.id != msk->mpc_endpoint_id)
+				msk->pm.local_addr_used++;
+		}
+
+		msk->pm.extra_subflows++;
+		found = 1;
+		break;
+	}
+	rcu_read_unlock();
+
+	return found;
+}
+
 static unsigned int
 fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
 				struct mptcp_addr_info *remote,
@@ -532,6 +601,10 @@ fill_local_addresses_vec(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
 	if (i)
 		return i;
 
+	/* If there is at least one MPTCP endpoint with a laminar flag */
+	if (mptcp_pm_get_endp_laminar_max(msk))
+		return fill_local_laminar_endp(msk, remote, locals);
+
 	/* Special case: peer sets the C flag, accept one ADD_ADDR if default
 	 * limits are used -- accepting no ADD_ADDR -- and use subflow endpoints
 	 */
@@ -707,6 +780,10 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		addr_max = pernet->endp_subflow_max;
 		WRITE_ONCE(pernet->endp_subflow_max, addr_max + 1);
 	}
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_LAMINAR) {
+		addr_max = pernet->endp_laminar_max;
+		WRITE_ONCE(pernet->endp_laminar_max, addr_max + 1);
+	}
 
 	pernet->endpoints++;
 	if (!entry->addr.port)
@@ -1100,6 +1177,10 @@ int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
 		addr_max = pernet->endp_subflow_max;
 		WRITE_ONCE(pernet->endp_subflow_max, addr_max - 1);
 	}
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_LAMINAR) {
+		addr_max = pernet->endp_laminar_max;
+		WRITE_ONCE(pernet->endp_laminar_max, addr_max - 1);
+	}
 
 	pernet->endpoints--;
 	list_del_rcu(&entry->list);
@@ -1182,6 +1263,7 @@ static void __reset_counters(struct pm_nl_pernet *pernet)
 {
 	WRITE_ONCE(pernet->endp_signal_max, 0);
 	WRITE_ONCE(pernet->endp_subflow_max, 0);
+	WRITE_ONCE(pernet->endp_laminar_max, 0);
 	pernet->endpoints = 0;
 }
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 0cd3333cafafad19a8c2c8ea302265af9f27a8bf..371084a3fc225391fe98ad42a2e2f63465119989 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1182,6 +1182,7 @@ void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
 u8 mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
 u8 mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_endp_laminar_max(const struct mptcp_sock *msk);
 u8 mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
 u8 mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
 
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 92a2a274262732a345b9ab185efd7da1f0a5773a..a28a483858852b49966b904a2f0dd44d8d118b5e 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -980,6 +980,8 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 			mptcp_pm_get_limit_add_addr_accepted(msk);
 		info->mptcpi_endp_subflow_max =
 			mptcp_pm_get_endp_subflow_max(msk);
+		info->mptcpi_endp_laminar_max =
+			mptcp_pm_get_endp_laminar_max(msk);
 	}
 
 	if (__mptcp_check_fallback(msk))

-- 
2.51.0

Re: [PATCH net-next 00/15] mptcp: pm: special case for c-flag + luminar endp

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 25 Sep 2025 12:32:35 +0200 you wrote:
> Here are some patches for the MPTCP PM, including some refactoring that
> I thought it would be best to send at the end of a cycle to avoid
> conflicts between net and net-next that could last a few weeks.
> 
> The most interesting changes are in the first and last patch, the rest
> are patches refactoring the code & tests to validate the modifications.
> 
> [...]

Here is the summary with links:
  - [net-next,01/15] mptcp: pm: in-kernel: usable client side with C-flag
    https://git.kernel.org/netdev/net-next/c/4b1ff850e0c1
  - [net-next,02/15] selftests: mptcp: join: validate C-flag + def limit
    https://git.kernel.org/netdev/net-next/c/008385efd05e
  - [net-next,03/15] mptcp: pm: in-kernel: refactor fill_local_addresses_vec
    https://git.kernel.org/netdev/net-next/c/8dc63ade451d
  - [net-next,04/15] mptcp: pm: in-kernel: refactor fill_remote_addresses_vec
    https://git.kernel.org/netdev/net-next/c/a845b2bbf26e
  - [net-next,05/15] mptcp: pm: rename 'subflows' to 'extra_subflows'
    https://git.kernel.org/netdev/net-next/c/c5273f6ca166
  - [net-next,06/15] mptcp: pm: in-kernel: rename 'subflows_max' to 'limit_extra_subflows'
    https://git.kernel.org/netdev/net-next/c/3eb3c9a9596a
  - [net-next,07/15] mptcp: pm: in-kernel: rename 'add_addr_signal_max' to 'endp_signal_max'
    https://git.kernel.org/netdev/net-next/c/45cae570664d
  - [net-next,08/15] mptcp: pm: in-kernel: rename 'add_addr_accept_max' to 'limit_add_addr_accepted'
    https://git.kernel.org/netdev/net-next/c/37712d84dfc2
  - [net-next,09/15] mptcp: pm: in-kernel: rename 'local_addr_max' to 'endp_subflow_max'
    https://git.kernel.org/netdev/net-next/c/e7757b6d3a62
  - [net-next,10/15] mptcp: pm: in-kernel: rename 'local_addr_list' to 'endp_list'
    https://git.kernel.org/netdev/net-next/c/35e71e43a56d
  - [net-next,11/15] mptcp: pm: in-kernel: rename 'addrs' to 'endpoints'
    https://git.kernel.org/netdev/net-next/c/e9aa044f4a1f
  - [net-next,12/15] mptcp: pm: in-kernel: remove stale_loss_cnt
    https://git.kernel.org/netdev/net-next/c/db9a0e3858ba
  - [net-next,13/15] mptcp: pm: in-kernel: reduce pernet struct size
    https://git.kernel.org/netdev/net-next/c/4984fe6254f8
  - [net-next,14/15] mptcp: pm: in-kernel: compare IDs instead of addresses
    https://git.kernel.org/netdev/net-next/c/f596293314b2
  - [net-next,15/15] mptcp: pm: in-kernel: add laminar endpoints
    https://git.kernel.org/netdev/net-next/c/539f6b9de39e

You are awesome, thank you!
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