diff mbox series

[net,1/2] mptcp: fix subflow accounting on close

Message ID 20220512232642.541301-2-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Commit 95d686517884a403412b000361cee2b08b2ed1e6
Delegated to: Netdev Maintainers
Headers show
Series mptcp: Subflow accounting fix | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 11 this patch: 11
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 5 this patch: 5
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 71 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mat Martineau May 12, 2022, 11:26 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

If the PM closes a fully established MPJ subflow or the subflow
creation errors out in it's early stage the subflows counter is
not bumped accordingly.

This change adds the missing accounting, additionally taking care
of updating accordingly the 'accept_subflow' flag.

Fixes: a88c9e496937 ("mptcp: do not block subflows creation on errors")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm.c       |  5 ++---
 net/mptcp/protocol.h | 14 ++++++++++++++
 net/mptcp/subflow.c  | 12 +++++++++---
 3 files changed, 25 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 01809eef29b4..aa51b100e033 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -178,14 +178,13 @@  void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk,
 	struct mptcp_pm_data *pm = &msk->pm;
 	bool update_subflows;
 
-	update_subflows = (ssk->sk_state == TCP_CLOSE) &&
-			  (subflow->request_join || subflow->mp_join);
+	update_subflows = subflow->request_join || subflow->mp_join;
 	if (!READ_ONCE(pm->work_pending) && !update_subflows)
 		return;
 
 	spin_lock_bh(&pm->lock);
 	if (update_subflows)
-		pm->subflows--;
+		__mptcp_pm_close_subflow(msk);
 
 	/* Even if this subflow is not really established, tell the PM to try
 	 * to pick the next ones, if possible.
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 3c1a3036550f..f4ce28bb0fdc 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -833,6 +833,20 @@  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_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))
+		WRITE_ONCE(msk->pm.accept_subflow, true);
+}
+
+static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
+{
+	spin_lock_bh(&msk->pm.lock);
+	__mptcp_pm_close_subflow(msk);
+	spin_unlock_bh(&msk->pm.lock);
+}
+
 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
 
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index aba260f547da..8c37087f0d84 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1422,20 +1422,20 @@  int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	struct sockaddr_storage addr;
 	int remote_id = remote->id;
 	int local_id = loc->id;
+	int err = -ENOTCONN;
 	struct socket *sf;
 	struct sock *ssk;
 	u32 remote_token;
 	int addrlen;
 	int ifindex;
 	u8 flags;
-	int err;
 
 	if (!mptcp_is_fully_established(sk))
-		return -ENOTCONN;
+		goto err_out;
 
 	err = mptcp_subflow_create_socket(sk, &sf);
 	if (err)
-		return err;
+		goto err_out;
 
 	ssk = sf->sk;
 	subflow = mptcp_subflow_ctx(ssk);
@@ -1492,6 +1492,12 @@  int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 failed:
 	subflow->disposable = 1;
 	sock_release(sf);
+
+err_out:
+	/* we account subflows before the creation, and this failures will not
+	 * be caught by sk_state_change()
+	 */
+	mptcp_pm_close_subflow(msk);
 	return err;
 }