[PATCH mptcp-next v2 0/4] mptcp: improve subflow creation on errors

[PATCH mptcp-next v2 0/4] mptcp: improve subflow creation on errors

[Paolo Abeni]

Currently when a subflow connection fails - either the TCP
connection is reset by the peer, or the MPJ handshake never
completes - the in kernel PM don't perform any further action.
Notably no additional subflow creation is attempted.

This series is aimed at improving the in-kernel path manager
behavior in the above scenario:
- each endpoint is used only once per connection (patch 2/4)
- on failure we try to move to the next subflow, if any
  (patch 3/4)

The first patch is minor cleanup, and the last patch adds
specific self-tests.

This should address/close:
https://github.com/multipath-tcp/mptcp_net-next/issues/235
https://github.com/multipath-tcp/mptcp_net-next/issues/242

@Phil: could you please have a spin in your testbed? this
should really cover your use case for good - modulo bugs

Paolo Abeni (4):
  mptcp: clean-up MPJ option writing.
  mptcp: keep track of used local endpoint
  mptcp: do not block subflows creation on errors
  selftests: mptcp: add tests for subflow creation failure

 net/mptcp/options.c                           | 65 ++++++++++++-------
 net/mptcp/pm.c                                | 29 +++++++++
 net/mptcp/pm_netlink.c                        |  8 ++-
 net/mptcp/protocol.c                          |  6 ++
 net/mptcp/protocol.h                          |  5 +-
 net/mptcp/subflow.c                           |  5 +-
 tools/testing/selftests/net/mptcp/config      |  1 +
 .../testing/selftests/net/mptcp/mptcp_join.sh | 65 ++++++++++++++++++-
 8 files changed, 156 insertions(+), 28 deletions(-)

-- 
2.33.1

[PATCH mptcp-next v2 1/4] mptcp: clean-up MPJ option writing.

[Paolo Abeni]

Check for all MPJ variant at once, this reduces the number
of conditionals traversed on average and will simplify the
next patch.

No functional change intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/options.c | 44 +++++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 8a1020e4285c..7a6a39b71633 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1381,27 +1381,29 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 
 		/* MPC is additionally mutually exclusive with MP_PRIO */
 		goto mp_capable_done;
-	} else if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
-		*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
-				      TCPOLEN_MPTCP_MPJ_SYN,
-				      opts->backup, opts->join_id);
-		put_unaligned_be32(opts->token, ptr);
-		ptr += 1;
-		put_unaligned_be32(opts->nonce, ptr);
-		ptr += 1;
-	} else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
-		*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
-				      TCPOLEN_MPTCP_MPJ_SYNACK,
-				      opts->backup, opts->join_id);
-		put_unaligned_be64(opts->thmac, ptr);
-		ptr += 2;
-		put_unaligned_be32(opts->nonce, ptr);
-		ptr += 1;
-	} else if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) {
-		*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
-				      TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
-		memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
-		ptr += 5;
+	} else if (OPTIONS_MPTCP_MPJ & opts->suboptions) {
+		if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
+			*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+					      TCPOLEN_MPTCP_MPJ_SYN,
+					      opts->backup, opts->join_id);
+			put_unaligned_be32(opts->token, ptr);
+			ptr += 1;
+			put_unaligned_be32(opts->nonce, ptr);
+			ptr += 1;
+		} else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
+			*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+					      TCPOLEN_MPTCP_MPJ_SYNACK,
+					      opts->backup, opts->join_id);
+			put_unaligned_be64(opts->thmac, ptr);
+			ptr += 2;
+			put_unaligned_be32(opts->nonce, ptr);
+			ptr += 1;
+		} else {
+			*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+					      TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
+			memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
+			ptr += 5;
+		}
 	} else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
 		u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
 		u8 echo = MPTCP_ADDR_ECHO;
-- 
2.33.1

[PATCH mptcp-next v2 2/4] mptcp: keep track of used local endpoint

[Paolo Abeni]

So that we can skip already used endpoint at local address
selection time.
This allows for fair local endpoints usage in case of subflow
failure.

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

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/pm.c         | 1 +
 net/mptcp/pm_netlink.c | 8 +++++++-
 net/mptcp/protocol.h   | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 761995a34124..1ff856dd92c4 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -376,6 +376,7 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 	WRITE_ONCE(msk->pm.accept_subflow, false);
 	WRITE_ONCE(msk->pm.remote_deny_join_id0, false);
 	msk->pm.status = 0;
+	bitmap_zero(msk->pm.endpoint_usage_mask, 256);
 
 	mptcp_pm_nl_data_init(msk);
 }
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 3186d33b5208..78b68a8216b6 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -173,6 +173,9 @@ select_local_address(const struct pm_nl_pernet *pernet,
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 			continue;
 
+		if (test_bit(entry->addr.id, msk->pm.endpoint_usage_mask))
+			continue;
+
 		if (entry->addr.family != sk->sk_family) {
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 			if ((entry->addr.family == AF_INET &&
@@ -512,8 +515,10 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 			check_work_pending(msk);
 			nr = fill_remote_addresses_vec(msk, fullmesh, addrs);
 			spin_unlock_bh(&msk->pm.lock);
-			for (i = 0; i < nr; i++)
+			for (i = 0; i < nr; i++) {
+				set_bit(local->addr.id, msk->pm.endpoint_usage_mask);
 				__mptcp_subflow_connect(sk, &local->addr, &addrs[i]);
+			}
 			spin_lock_bh(&msk->pm.lock);
 			return;
 		}
@@ -1282,6 +1287,7 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
 		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow);
 		if (remove_subflow)
 			mptcp_pm_remove_subflow(msk, &list);
+		clear_bit(addr->id, msk->pm.endpoint_usage_mask);
 		release_sock(sk);
 
 next:
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index a6a4bd7de5b4..d384f285b6c1 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -190,6 +190,7 @@ struct mptcp_pm_data {
 
 	spinlock_t	lock;		/*protects the whole PM data */
 
+	DECLARE_BITMAP(endpoint_usage_mask, 256);
 	u8		addr_signal;
 	bool		server_side;
 	bool		work_pending;
-- 
2.33.1

[PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[Paolo Abeni]

If the MPTCP configuration allows for multiple subflows
creation, and the first additional subflows never reach
the fully established status - e.g. due to packets drop or
reset - the in kernel path manager do not move to the
next subflow.

This patch introduces a new PM helper to cope with MPJ
subflow creation failure and delay and hook it where appropriate.

Such helper triggers additional subflow creation, as needed
and updates the PM subflow counter, if the current one is
closing.

Note that we don't need an additional timer to catch timeout
and/or long delay in connection completion: we just need to
measure the time elapsed since the subflow creation every
time we emit an MPJ sub-option.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
v1 -> v2:
 - explicitly hook on subflow close instead of error notification
 - fix checkpatch issue (Mat)
 - introduce and use a new pm helper to cope with subflow close
 - update pm subflow counters on close
---
 net/mptcp/options.c  | 21 ++++++++++++++++++---
 net/mptcp/pm.c       | 28 ++++++++++++++++++++++++++++
 net/mptcp/protocol.c |  6 ++++++
 net/mptcp/protocol.h |  4 +++-
 net/mptcp/subflow.c  |  5 ++++-
 5 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 7a6a39b71633..00a8697addcd 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1257,10 +1257,10 @@ static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 			 struct mptcp_out_options *opts)
 {
-	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
-		const struct sock *ssk = (const struct sock *)tp;
-		struct mptcp_subflow_context *subflow;
+	const struct sock *ssk = (const struct sock *)tp;
+	struct mptcp_subflow_context *subflow;
 
+	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
 		subflow = mptcp_subflow_ctx(ssk);
 		subflow->send_mp_fail = 0;
 
@@ -1382,6 +1382,21 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 		/* MPC is additionally mutually exclusive with MP_PRIO */
 		goto mp_capable_done;
 	} else if (OPTIONS_MPTCP_MPJ & opts->suboptions) {
+		if (ssk) {
+			/* we are still in the MPJ handshake and "a lot" of time passed
+			 * e.g. due to syn retranmissions. We can attempt next
+			 * subflow creation
+			 */
+			subflow = mptcp_subflow_ctx(ssk);
+			if (subflow->start_stamp &&
+			    unlikely(after(tcp_jiffies32, subflow->start_stamp + HZ / 10))) {
+				mptcp_pm_subflow_check_next(mptcp_sk(subflow->conn), ssk, subflow);
+
+				/* avoid triggering the PM multiple times due to timeout */
+				subflow->start_stamp = 0;
+			}
+		}
+
 		if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
 			*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
 					      TCPOLEN_MPTCP_MPJ_SYN,
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 1ff856dd92c4..8948e639d213 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -172,6 +172,34 @@ void mptcp_pm_subflow_established(struct mptcp_sock *msk)
 	spin_unlock_bh(&pm->lock);
 }
 
+void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk,
+				 const struct mptcp_subflow_context *subflow)
+{
+	struct mptcp_pm_data *pm = &msk->pm;
+	bool closed;
+
+	closed = ssk->sk_state == TCP_CLOSE;
+	if (subflow->fully_established && !closed)
+		return;
+
+	spin_lock_bh(&pm->lock);
+	if (closed) {
+		pm->local_addr_used--;
+		pm->subflows--;
+		/* do not enable the pm worker: we don't want to pick again
+		 * the just closed subflow
+		 */
+	}
+
+	/* Even if this subflow is not really established, tell the PM to try
+	 * to pick the next one, if possible.
+	 */
+	if (pm->work_pending)
+		mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
+
+	spin_unlock_bh(&pm->lock);
+}
+
 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
 {
 	pr_debug("msk=%p", msk);
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index ef2125798e64..2ee2fe97c553 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2351,6 +2351,12 @@ void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 {
 	if (sk->sk_state == TCP_ESTABLISHED)
 		mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
+
+	/* subflow aborted before reaching the fully_established status
+	 * attempt the creation of the next subflow
+	 */
+	mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow);
+
 	__mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
 }
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d384f285b6c1..4da1ef964b88 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -433,6 +433,7 @@ struct mptcp_subflow_context {
 		stale : 1;	    /* unable to snd/rcv data, do not use for xmit */
 	enum mptcp_data_avail data_avail;
 	u32	remote_nonce;
+	u32	start_stamp;
 	u64	thmac;
 	u32	local_nonce;
 	u32	remote_token;
@@ -733,7 +734,8 @@ void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk,
 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
-void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
+void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk,
+				 const struct mptcp_subflow_context *subflow);
 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
 				const struct mptcp_addr_info *addr);
 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 0f90bd61de01..76556743e952 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1273,7 +1273,8 @@ void __mptcp_error_report(struct sock *sk)
 
 static void subflow_error_report(struct sock *ssk)
 {
-	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+	struct sock *sk = subflow->conn;
 
 	mptcp_data_lock(sk);
 	if (!sock_owned_by_user(sk))
@@ -1444,6 +1445,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	subflow->remote_id = remote_id;
 	subflow->request_join = 1;
 	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	subflow->start_stamp = tcp_jiffies32;
 	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
 
 	mptcp_add_pending_subflow(msk, subflow);
@@ -1461,6 +1463,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	spin_lock_bh(&msk->join_list_lock);
 	list_del(&subflow->node);
 	spin_unlock_bh(&msk->join_list_lock);
+	mptcp_pm_subflow_check_next(msk, ssk, subflow);
 	sock_put(mptcp_subflow_tcp_sock(subflow));
 
 failed:
-- 
2.33.1

Re: [PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[kernel test robot]

Hi Paolo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mptcp/export]
[cannot apply to shuah-kselftest/next linus/master v5.16-rc2 next-20211124]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
base:   https://github.com/multipath-tcp/mptcp_net-next.git export
config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20211125/202111250633.wEMz7JQe-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/6af8e28040c093866aa60ede3f980b53ab3594a5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
        git checkout 6af8e28040c093866aa60ede3f980b53ab3594a5
        # save the config file to linux build tree
        make W=1 ARCH=um SUBARCH=i386

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> net/mptcp/pm.c:203:6: warning: no previous prototype for 'mptcp_pm_subflow_closed' [-Wmissing-prototypes]
     203 | void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
         |      ^~~~~~~~~~~~~~~~~~~~~~~


vim +/mptcp_pm_subflow_closed +203 net/mptcp/pm.c

6af8e28040c093 Paolo Abeni   2021-11-24  202  
1b1c7a0ef7f323 Peter Krystad 2020-03-27 @203  void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
1b1c7a0ef7f323 Peter Krystad 2020-03-27  204  {
1b1c7a0ef7f323 Peter Krystad 2020-03-27  205  	pr_debug("msk=%p", msk);
1b1c7a0ef7f323 Peter Krystad 2020-03-27  206  }
1b1c7a0ef7f323 Peter Krystad 2020-03-27  207  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2124 bytes --]

Hi Paolo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mptcp/export]
[cannot apply to shuah-kselftest/next linus/master v5.16-rc2 next-20211124]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
base:   https://github.com/multipath-tcp/mptcp_net-next.git export
config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20211125/202111250633.wEMz7JQe-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/6af8e28040c093866aa60ede3f980b53ab3594a5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
        git checkout 6af8e28040c093866aa60ede3f980b53ab3594a5
        # save the config file to linux build tree
        make W=1 ARCH=um SUBARCH=i386

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> net/mptcp/pm.c:203:6: warning: no previous prototype for 'mptcp_pm_subflow_closed' [-Wmissing-prototypes]
     203 | void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
         |      ^~~~~~~~~~~~~~~~~~~~~~~


vim +/mptcp_pm_subflow_closed +203 net/mptcp/pm.c

6af8e28040c093 Paolo Abeni   2021-11-24  202  
1b1c7a0ef7f323 Peter Krystad 2020-03-27 @203  void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
1b1c7a0ef7f323 Peter Krystad 2020-03-27  204  {
1b1c7a0ef7f323 Peter Krystad 2020-03-27  205  	pr_debug("msk=%p", msk);
1b1c7a0ef7f323 Peter Krystad 2020-03-27  206  }
1b1c7a0ef7f323 Peter Krystad 2020-03-27  207  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

Re: [PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[Paolo Abeni]

On Thu, 2021-11-25 at 06:52 +0800, kernel test robot wrote:
> Hi Paolo,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on mptcp/export]
> [cannot apply to shuah-kselftest/next linus/master v5.16-rc2 next-20211124]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
> base:   https://github.com/multipath-tcp/mptcp_net-next.git export
> config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20211125/202111250633.wEMz7JQe-lkp@intel.com/config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
>         # https://github.com/0day-ci/linux/commit/6af8e28040c093866aa60ede3f980b53ab3594a5
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
>         git checkout 6af8e28040c093866aa60ede3f980b53ab3594a5
>         # save the config file to linux build tree
>         make W=1 ARCH=um SUBARCH=i386
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
> > > net/mptcp/pm.c:203:6: warning: no previous prototype for 'mptcp_pm_subflow_closed' [-Wmissing-prototypes]
>      203 | void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
>          |      ^~~~~~~~~~~~~~~~~~~~~~~
> 
> 
> vim +/mptcp_pm_subflow_closed +203 net/mptcp/pm.c
> 
> 6af8e28040c093 Paolo Abeni   2021-11-24  202  
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27 @203  void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  204  {
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  205  	pr_debug("msk=%p", msk);
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  206  }
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  207  

All the CI warning are caused by this function lacking a declaration.
The solution would be just dropping 'mptcp_pm_subflow_closed()', as
mptcp_pm_subflow_check_next() is already doing the real work.

@Mat: assuming there are no other issues, could you please do that in
patchwork or do you prefer me to post a v3?

Thanks!

Paolo

Re: [PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[Paolo Abeni]

[-- Attachment #1: Type: text/plain, Size: 2491 bytes --]

On Thu, 2021-11-25 at 06:52 +0800, kernel test robot wrote:
> Hi Paolo,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on mptcp/export]
> [cannot apply to shuah-kselftest/next linus/master v5.16-rc2 next-20211124]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
> base:   https://github.com/multipath-tcp/mptcp_net-next.git export
> config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20211125/202111250633.wEMz7JQe-lkp(a)intel.com/config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
>         # https://github.com/0day-ci/linux/commit/6af8e28040c093866aa60ede3f980b53ab3594a5
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
>         git checkout 6af8e28040c093866aa60ede3f980b53ab3594a5
>         # save the config file to linux build tree
>         make W=1 ARCH=um SUBARCH=i386
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
> > > net/mptcp/pm.c:203:6: warning: no previous prototype for 'mptcp_pm_subflow_closed' [-Wmissing-prototypes]
>      203 | void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
>          |      ^~~~~~~~~~~~~~~~~~~~~~~
> 
> 
> vim +/mptcp_pm_subflow_closed +203 net/mptcp/pm.c
> 
> 6af8e28040c093 Paolo Abeni   2021-11-24  202  
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27 @203  void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  204  {
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  205  	pr_debug("msk=%p", msk);
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  206  }
> 1b1c7a0ef7f323 Peter Krystad 2020-03-27  207  

All the CI warning are caused by this function lacking a declaration.
The solution would be just dropping 'mptcp_pm_subflow_closed()', as
mptcp_pm_subflow_check_next() is already doing the real work.

@Mat: assuming there are no other issues, could you please do that in
patchwork or do you prefer me to post a v3?

Thanks!

Paolo

Re: [PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[kernel test robot]

Hi Paolo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mptcp/export]
[cannot apply to shuah-kselftest/next linus/master v5.16-rc2 next-20211124]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
base:   https://github.com/multipath-tcp/mptcp_net-next.git export
config: i386-randconfig-a002-20211124 (https://download.01.org/0day-ci/archive/20211125/202111251042.JLoJ33k0-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 67a1c45def8a75061203461ab0060c75c864df1c)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/6af8e28040c093866aa60ede3f980b53ab3594a5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
        git checkout 6af8e28040c093866aa60ede3f980b53ab3594a5
        # save the config file to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> net/mptcp/pm.c:203:6: warning: no previous prototype for function 'mptcp_pm_subflow_closed' [-Wmissing-prototypes]
   void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
        ^
   net/mptcp/pm.c:203:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
   ^
   static 
   1 warning generated.


vim +/mptcp_pm_subflow_closed +203 net/mptcp/pm.c

6af8e28040c0938 Paolo Abeni   2021-11-24  202  
1b1c7a0ef7f323f Peter Krystad 2020-03-27 @203  void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
1b1c7a0ef7f323f Peter Krystad 2020-03-27  204  {
1b1c7a0ef7f323f Peter Krystad 2020-03-27  205  	pr_debug("msk=%p", msk);
1b1c7a0ef7f323f Peter Krystad 2020-03-27  206  }
1b1c7a0ef7f323f Peter Krystad 2020-03-27  207  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH mptcp-next v2 3/4] mptcp: do not block subflows creation on errors

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2602 bytes --]

Hi Paolo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mptcp/export]
[cannot apply to shuah-kselftest/next linus/master v5.16-rc2 next-20211124]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
base:   https://github.com/multipath-tcp/mptcp_net-next.git export
config: i386-randconfig-a002-20211124 (https://download.01.org/0day-ci/archive/20211125/202111251042.JLoJ33k0-lkp(a)intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 67a1c45def8a75061203461ab0060c75c864df1c)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/6af8e28040c093866aa60ede3f980b53ab3594a5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Paolo-Abeni/mptcp-improve-subflow-creation-on-errors/20211125-005137
        git checkout 6af8e28040c093866aa60ede3f980b53ab3594a5
        # save the config file to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> net/mptcp/pm.c:203:6: warning: no previous prototype for function 'mptcp_pm_subflow_closed' [-Wmissing-prototypes]
   void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
        ^
   net/mptcp/pm.c:203:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
   ^
   static 
   1 warning generated.


vim +/mptcp_pm_subflow_closed +203 net/mptcp/pm.c

6af8e28040c0938 Paolo Abeni   2021-11-24  202  
1b1c7a0ef7f323f Peter Krystad 2020-03-27 @203  void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
1b1c7a0ef7f323f Peter Krystad 2020-03-27  204  {
1b1c7a0ef7f323f Peter Krystad 2020-03-27  205  	pr_debug("msk=%p", msk);
1b1c7a0ef7f323f Peter Krystad 2020-03-27  206  }
1b1c7a0ef7f323f Peter Krystad 2020-03-27  207  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[PATCH mptcp-next v2 4/4] selftests: mptcp: add tests for subflow creation failure

[Paolo Abeni]

Verify that, when multiple endpoints are available, subflows
creation proceed even when the first additional subflow creation
fails - due to packet drop on the relevant link

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
v1 -> v2:
 - add missing NF kconfig
 - add more test-cases (drop, later subflow creation)
---
 tools/testing/selftests/net/mptcp/config      |  1 +
 .../testing/selftests/net/mptcp/mptcp_join.sh | 65 ++++++++++++++++++-
 2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/mptcp/config b/tools/testing/selftests/net/mptcp/config
index 419e71560fd1..41e94e004bdc 100644
--- a/tools/testing/selftests/net/mptcp/config
+++ b/tools/testing/selftests/net/mptcp/config
@@ -18,4 +18,5 @@ CONFIG_NFT_TPROXY=m
 CONFIG_NFT_SOCKET=m
 CONFIG_IP_ADVANCED_ROUTER=y
 CONFIG_IP_MULTIPLE_TABLES=y
+CONFIG_IP_NF_TARGET_REJECT=m
 CONFIG_IPV6_MULTIPLE_TABLES=y
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 2684ef9c0d42..6d342f9985b8 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -975,6 +975,22 @@ chk_link_usage()
 	fi
 }
 
+wait_for_tw()
+{
+	local timeout_ms=$((timeout_poll * 1000))
+	local time=0
+	local ns=$1
+
+	while [ $time -lt $timeout_ms ]; do
+		local cnt=`ip netns exec $ns ss -t state time-wait |wc -l`
+
+		[ "$cnt" = 1 ] && return 1
+		time=$((time + 100))
+		sleep 0.1
+	done
+	return 1
+}
+
 subflows_tests()
 {
 	reset
@@ -1032,6 +1048,48 @@ subflows_tests()
 	chk_join_nr "single subflow, dev" 1 1 1
 }
 
+subflows_error_tests()
+{
+	# multiple subflows, with subflow creation error
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags subflow
+	ip netns exec $ns1 iptables -A INPUT -s 10.0.3.2 -p tcp -j REJECT
+	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow
+	chk_join_nr "multiple subflows, with failing subflow" 1 1 1
+
+	# multiple subflows, with subflow timeout on MPJ
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags subflow
+	ip netns exec $ns1 iptables -A INPUT -s 10.0.3.2 -p tcp -j DROP
+	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow
+	chk_join_nr "multiple subflows, with subflow timeout" 1 1 1
+
+	# multiple subflows, check that the endpoint corresponding to
+	# closed subflow (due to reset) is not reused if additional
+	# subflows are added later
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 1
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 1
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	ip netns exec $ns1 iptables -A INPUT -s 10.0.3.2 -p tcp -j REJECT
+	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow &
+
+	# mpj subflow will be in TW after the reset
+	wait_for_tw $ns2
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags subflow
+	wait
+
+	# additional subflow could be created only if the PM select
+	# the later endpoint, skipping the already used one
+	chk_join_nr "multiple subflows, fair usage on close" 1 1 1
+}
+
 signal_address_tests()
 {
 	# add_address, unused
@@ -1840,6 +1898,7 @@ fullmesh_tests()
 all_tests()
 {
 	subflows_tests
+	subflows_error_tests
 	signal_address_tests
 	link_failure_tests
 	add_addr_timeout_tests
@@ -1859,6 +1918,7 @@ usage()
 {
 	echo "mptcp_join usage:"
 	echo "  -f subflows_tests"
+	echo "  -f subflows_error_tests"
 	echo "  -s signal_address_tests"
 	echo "  -l link_failure_tests"
 	echo "  -t add_addr_timeout_tests"
@@ -1907,11 +1967,14 @@ if [ $do_all_tests -eq 1 ]; then
 	exit $ret
 fi
 
-while getopts 'fsltra64bpkdmchCS' opt; do
+while getopts 'fesltra64bpkdmchCS' opt; do
 	case $opt in
 		f)
 			subflows_tests
 			;;
+		e)
+			subflows_error_tests
+			;;
 		s)
 			signal_address_tests
 			;;
-- 
2.33.1

Re: selftests: mptcp: add tests for subflow creation failure: Build Failure

[MPTCP CI]

Hi Paolo,

Thank you for your modifications, that's great!

But sadly, our CI spotted some issues with it when trying to build it.

You can find more details there:

  https://patchwork.kernel.org/project/mptcp/patch/44593f9acfe286b9d18973e13877c1e48a15706c.1637770883.git.pabeni@redhat.com/
  https://github.com/multipath-tcp/mptcp_net-next/actions/runs/1501022122

Status: failure
Initiator: MPTCPimporter
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/37cb636d6d72

Feel free to reply to this email if you cannot access logs, if you need
some support to fix the error, if this doesn't seem to be caused by your
modifications or if the error is a false positive one.

Cheers,
MPTCP GH Action bot

Re: selftests: mptcp: add tests for subflow creation failure: Build Failure

[MPTCP CI]

Hi Paolo,

Thank you for your modifications, that's great!

But sadly, our CI spotted some issues with it when trying to build it.

You can find more details there:

  https://patchwork.kernel.org/project/mptcp/patch/44593f9acfe286b9d18973e13877c1e48a15706c.1637770883.git.pabeni@redhat.com/
  https://github.com/multipath-tcp/mptcp_net-next/actions/runs/1501462418

Status: failure
Initiator: MPTCPimporter
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/e6316e20ae3b

Feel free to reply to this email if you cannot access logs, if you need
some support to fix the error, if this doesn't seem to be caused by your
modifications or if the error is a false positive one.

Cheers,
MPTCP GH Action bot