[PATCH net 0/4] mptcp: a bunch of assorted fixes

This series pulls a few fixes for the MPTCP datapath.
Most issues addressed here has been recently introduced
with the recent reworks, with the notable exception of
the first patch, which addresses an issue present since
the early days

Paolo Abeni (4):
  mptcp: fix security context on server socket
  mptcp: properly annotate nested lock
  mptcp: push pending frames when subflow has free space
  mptcp: fix pending data accounting

 net/mptcp/options.c                               | 13 ++++++++-----
 net/mptcp/protocol.c                              | 11 ++++++-----
 net/mptcp/protocol.h                              |  2 +-
 tools/testing/selftests/net/mptcp/simult_flows.sh |  6 +++---
 4 files changed, 18 insertions(+), 14 deletions(-)

-- 
2.26.2

Currently MPTCP is not propagating the security context
from the ingress request socket to newly created msk
at clone time.

Address the issue invoking the missing security helper.

Fixes: cf7da0d66cc1 ("mptcp: Create SUBFLOW socket for incoming connections")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/protocol.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index b812aaae8044..d24243a28fce 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c

@@ -2699,6 +2699,8 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 	sock_reset_flag(nsk, SOCK_RCU_FREE);
 	/* will be fully established after successful MPC subflow creation */
 	inet_sk_state_store(nsk, TCP_SYN_RECV);
+
+	security_inet_csk_clone(nsk, req);
 	bh_unlock_sock(nsk);
 
 	/* keep a single reference */

-- 
2.26.2

When multiple subflows are active, we can receive a
window update on subflow with no write space available.
MPTCP will try to push frames on such subflow and will
fail. Pending frames will be pushed only after receiving
a window update on a subflow with some wspace available.

Overall the above could lead to suboptimal aggregate
bandwidth usage.

Instead, we should try to push pending frames as soon as
the subflow reaches both conditions mentioned above.

We can finally enable self-tests with asymmetric links,
as the above makes them finally pass.

Fixes: 6f8a612a33e4 ("mptcp: keep track of advertised windows right edge")
Reviewed-by: Mat Martineau <redacted>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/options.c                               | 13 ++++++++-----
 net/mptcp/protocol.c                              |  2 +-
 net/mptcp/protocol.h                              |  2 +-
 tools/testing/selftests/net/mptcp/simult_flows.sh |  6 +++---
 4 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index c5328f407aab..1fbd305ebd92 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c

@@ -873,10 +873,13 @@ static void ack_update_msk(struct mptcp_sock *msk,
 
 	new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
 
-	if (after64(new_wnd_end, msk->wnd_end)) {
+	if (after64(new_wnd_end, msk->wnd_end))
 		msk->wnd_end = new_wnd_end;
-		__mptcp_wnd_updated(sk, ssk);
-	}
+
+	/* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
+	if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)) &&
+	    sk_stream_memory_free(ssk))
+		__mptcp_check_push(sk, ssk);
 
 	if (after64(new_snd_una, old_snd_una)) {
 		msk->snd_una = new_snd_una;

@@ -942,8 +945,8 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 		 * helpers are cheap.
 		 */
 		mptcp_data_lock(subflow->conn);
-		if (mptcp_send_head(subflow->conn))
-			__mptcp_wnd_updated(subflow->conn, sk);
+		if (sk_stream_memory_free(sk))
+			__mptcp_check_push(subflow->conn, sk);
 		__mptcp_data_acked(subflow->conn);
 		mptcp_data_unlock(subflow->conn);
 		return;

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 64c0c54c80e8..b53a91801a6c 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c

@@ -2915,7 +2915,7 @@ void __mptcp_data_acked(struct sock *sk)
 		mptcp_schedule_work(sk);
 }
 
-void __mptcp_wnd_updated(struct sock *sk, struct sock *ssk)
+void __mptcp_check_push(struct sock *sk, struct sock *ssk)
 {
 	if (!mptcp_send_head(sk))
 		return;

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 7cf9d110b85f..d67de793d363 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h

@@ -503,7 +503,7 @@ void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
 bool mptcp_finish_join(struct sock *sk);
 bool mptcp_schedule_work(struct sock *sk);
-void __mptcp_wnd_updated(struct sock *sk, struct sock *ssk);
+void __mptcp_check_push(struct sock *sk, struct sock *ssk);
 void __mptcp_data_acked(struct sock *sk);
 void mptcp_subflow_eof(struct sock *sk);
 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);

diff --git a/tools/testing/selftests/net/mptcp/simult_flows.sh b/tools/testing/selftests/net/mptcp/simult_flows.sh
index 2f649b431456..f039ee57eb3c 100755
--- a/tools/testing/selftests/net/mptcp/simult_flows.sh
+++ b/tools/testing/selftests/net/mptcp/simult_flows.sh

@@ -287,7 +287,7 @@ run_test 10 10 0 0 "balanced bwidth"
 run_test 10 10 1 50 "balanced bwidth with unbalanced delay"
 
 # we still need some additional infrastructure to pass the following test-cases
-# run_test 30 10 0 0 "unbalanced bwidth"
-# run_test 30 10 1 50 "unbalanced bwidth with unbalanced delay"
-# run_test 30 10 50 1 "unbalanced bwidth with opposed, unbalanced delay"
+run_test 30 10 0 0 "unbalanced bwidth"
+run_test 30 10 1 50 "unbalanced bwidth with unbalanced delay"
+run_test 30 10 50 1 "unbalanced bwidth with opposed, unbalanced delay"
 exit $ret

-- 
2.26.2

When sendmsg() needs to wait for memory, the pending data
is not updated. That causes a drift in forward memory allocation,
leading to stall and/or warnings at socket close time.

This change addresses the above issue moving the pending data
counter update inside the sendmsg() main loop.

Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks")
Reviewed-by: Mat Martineau <redacted>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/protocol.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index b53a91801a6c..09b19aa2f205 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c

@@ -1658,6 +1658,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		frag_truesize += psize;
 		pfrag->offset += frag_truesize;
 		WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
+		msk->tx_pending_data += psize;
 
 		/* charge data on mptcp pending queue to the msk socket
 		 * Note: we charge such data both to sk and ssk

@@ -1683,10 +1684,8 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 			goto out;
 	}
 
-	if (copied) {
-		msk->tx_pending_data += copied;
+	if (copied)
 		mptcp_push_pending(sk, msg->msg_flags);
-	}
 
 out:
 	release_sock(sk);

-- 
2.26.2

MPTCP closes the subflows while holding the msk-level lock.
While acquiring the subflow socket lock we need to use the
correct nested annotation, or we can hit a lockdep splat
at runtime.

Reported-and-tested-by: Geliang Tang <redacted>
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/protocol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d24243a28fce..64c0c54c80e8 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c

@@ -2119,7 +2119,7 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 
 	list_del(&subflow->node);
 
-	lock_sock(ssk);
+	lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
 
 	/* if we are invoked by the msk cleanup code, the subflow is
 	 * already orphaned

-- 
2.26.2

On Wed, 16 Dec 2020, Paolo Abeni wrote:

Currently MPTCP is not propagating the security context
from the ingress request socket to newly created msk
at clone time.

Address the issue invoking the missing security helper.

Fixes: cf7da0d66cc1 ("mptcp: Create SUBFLOW socket for incoming connections")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/mptcp/protocol.c | 2 ++
1 file changed, 2 insertions(+)

Reviewed-by: Mat Martineau <redacted>

--
Mat Martineau
Intel

On Wed, 16 Dec 2020, Paolo Abeni wrote:

MPTCP closes the subflows while holding the msk-level lock.
While acquiring the subflow socket lock we need to use the
correct nested annotation, or we can hit a lockdep splat
at runtime.

Reported-and-tested-by: Geliang Tang <redacted>
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/mptcp/protocol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Mat Martineau <redacted>

--
Mat Martineau
Intel

Hello:

This series was applied to netdev/net.git (refs/heads/master):

On Wed, 16 Dec 2020 12:48:31 +0100 you wrote:

This series pulls a few fixes for the MPTCP datapath.
Most issues addressed here has been recently introduced
with the recent reworks, with the notable exception of
the first patch, which addresses an issue present since
the early days

Paolo Abeni (4):
  mptcp: fix security context on server socket
  mptcp: properly annotate nested lock
  mptcp: push pending frames when subflow has free space
  mptcp: fix pending data accounting

[...]

Here is the summary with links:
  - [net,1/4] mptcp: fix security context on server socket
    https://git.kernel.org/netdev/net/c/0c14846032f2
  - [net,2/4] mptcp: properly annotate nested lock
    https://git.kernel.org/netdev/net/c/3f8b2667f257
  - [net,3/4] mptcp: push pending frames when subflow has free space
    https://git.kernel.org/netdev/net/c/219d04992b68
  - [net,4/4] mptcp: fix pending data accounting
    https://git.kernel.org/netdev/net/c/13e1603739e5

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html