Merge branch 'mptcp-mib-counters-for-mpj-tx-misc-improvements'

Matthieu Baerts says:

====================
mptcp: MIB counters for MPJ TX + misc improvements

Recently, a few issues have been discovered around the creation of
additional subflows. Without these counters, it was difficult to point
out the reason why some subflows were not created as expected.

In patch 3, all error paths from __mptcp_subflow_connect() are covered,
except the one related to the 'fully established mode', because it can
only happen with the userspace PM, which will propagate the error to the
userspace in this case (ENOTCONN).

These new counters are also verified in the MPTCP Join selftest in patch
6.

While at it, a few other patches are improving the MPTCP path-manager
code ...

 - Patch 1: 'flush' related helpers are renamed to avoid confusions
 - Patch 2: directly pass known ID and flags to create a new subflow,
            i/o getting them later by iterating over all endpoints again

... and the MPJoin selftests:

 - Patch 4: reduce the number of positional parameters
 - Patch 5: only one line for the 'join' checks, instead of 3
 - Patch 7: more explicit check names, instead of sometimes too cryptic
            ones: rtx, ptx, ftx, ctx, fclzrx, sum
 - Patch 8: specify client/server instead of 'invert' for some checks
            not suggesting one specific direction
 - Patch 9: mute errors of mptcp_connect when ran in the background
 - Patch 10: simplify checksum_tests by using a for-loop
 - Patch 11: remove 'define' re-definitions
====================

Link: https://patch.msgid.link/20240902-net-next-mptcp-mib-mpjtx-misc-v1-0-d3e0f3773b90@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/mptcp/mib.c

@@ -25,6 +25,10 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("MPJoinSynAckHMacFailure", MPTCP_MIB_JOINSYNACKMAC),
 	SNMP_MIB_ITEM("MPJoinAckRx", MPTCP_MIB_JOINACKRX),
 	SNMP_MIB_ITEM("MPJoinAckHMacFailure", MPTCP_MIB_JOINACKMAC),
+	SNMP_MIB_ITEM("MPJoinSynTx", MPTCP_MIB_JOINSYNTX),
+	SNMP_MIB_ITEM("MPJoinSynTxCreatSkErr", MPTCP_MIB_JOINSYNTXCREATSKERR),
+	SNMP_MIB_ITEM("MPJoinSynTxBindErr", MPTCP_MIB_JOINSYNTXBINDERR),
+	SNMP_MIB_ITEM("MPJoinSynTxConnectErr", MPTCP_MIB_JOINSYNTXCONNECTERR),
 	SNMP_MIB_ITEM("DSSNotMatching", MPTCP_MIB_DSSNOMATCH),
 	SNMP_MIB_ITEM("InfiniteMapTx", MPTCP_MIB_INFINITEMAPTX),
 	SNMP_MIB_ITEM("InfiniteMapRx", MPTCP_MIB_INFINITEMAPRX),

net/mptcp/mib.h

@@ -20,6 +20,10 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_JOINSYNACKMAC,	/* HMAC was wrong on SYN/ACK + MP_JOIN */
 	MPTCP_MIB_JOINACKRX,		/* Received an ACK + MP_JOIN */
 	MPTCP_MIB_JOINACKMAC,		/* HMAC was wrong on ACK + MP_JOIN */
+	MPTCP_MIB_JOINSYNTX,		/* Sending a SYN + MP_JOIN */
+	MPTCP_MIB_JOINSYNTXCREATSKERR,	/* Not able to create a socket when sending a SYN + MP_JOIN */
+	MPTCP_MIB_JOINSYNTXBINDERR,	/* Not able to bind() the address when sending a SYN + MP_JOIN */
+	MPTCP_MIB_JOINSYNTXCONNECTERR,	/* Not able to connect() when sending a SYN + MP_JOIN */
 	MPTCP_MIB_DSSNOMATCH,		/* Received a new mapping that did not match the previous one */
 	MPTCP_MIB_INFINITEMAPTX,	/* Sent an infinite mapping */
 	MPTCP_MIB_INFINITEMAPRX,	/* Received an infinite mapping */

net/mptcp/pm.c

@@ -430,17 +430,6 @@ bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc)
 	return mptcp_pm_nl_is_backup(msk, &skc_local);
 }
 
-int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
-					 u8 *flags, int *ifindex)
-{
-	*flags = 0;
-	*ifindex = 0;
-
-	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk, id, flags, ifindex);
-	return mptcp_pm_nl_get_flags_and_ifindex_by_id(msk, id, flags, ifindex);
-}
-
 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info)
 {
 	if (info->attrs[MPTCP_PM_ATTR_TOKEN])

net/mptcp/pm_netlink.c

@@ -149,7 +149,7 @@ static bool lookup_subflow_by_daddr(const struct list_head *list,
 static bool
 select_local_address(const struct pm_nl_pernet *pernet,
 		     const struct mptcp_sock *msk,
-		     struct mptcp_pm_addr_entry *new_entry)
+		     struct mptcp_pm_local *new_local)
 {
 	struct mptcp_pm_addr_entry *entry;
 	bool found = false;
@@ -164,7 +164,9 @@ select_local_address(const struct pm_nl_pernet *pernet,
 		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 			continue;
 
-		*new_entry = *entry;
+		new_local->addr = entry->addr;
+		new_local->flags = entry->flags;
+		new_local->ifindex = entry->ifindex;
 		found = true;
 		break;
 	}
@@ -175,7 +177,7 @@ select_local_address(const struct pm_nl_pernet *pernet,
 
 static bool
 select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
-		      struct mptcp_pm_addr_entry *new_entry)
+		     struct mptcp_pm_local *new_local)
 {
 	struct mptcp_pm_addr_entry *entry;
 	bool found = false;
@@ -193,7 +195,9 @@ select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
 			continue;
 
-		*new_entry = *entry;
+		new_local->addr = entry->addr;
+		new_local->flags = entry->flags;
+		new_local->ifindex = entry->ifindex;
 		found = true;
 		break;
 	}
@@ -524,11 +528,11 @@ __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;
-	struct mptcp_pm_addr_entry local;
 	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));
@@ -629,7 +633,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 
 		spin_unlock_bh(&msk->pm.lock);
 		for (i = 0; i < nr; i++)
-			__mptcp_subflow_connect(sk, &local.addr, &addrs[i]);
+			__mptcp_subflow_connect(sk, &local, &addrs[i]);
 		spin_lock_bh(&msk->pm.lock);
 	}
 	mptcp_pm_nl_check_work_pending(msk);
@@ -650,7 +654,7 @@ static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
  */
 static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 					     struct mptcp_addr_info *remote,
-					     struct mptcp_addr_info *addrs)
+					     struct mptcp_pm_local *locals)
 {
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
@@ -673,13 +677,15 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 			continue;
 
 		if (msk->pm.subflows < subflows_max) {
-			msk->pm.subflows++;
-			addrs[i] = entry->addr;
+			locals[i].addr = entry->addr;
+			locals[i].flags = entry->flags;
+			locals[i].ifindex = entry->ifindex;
 
 			/* Special case for ID0: set the correct ID */
-			if (mptcp_addresses_equal(&entry->addr, &mpc_addr, entry->addr.port))
-				addrs[i].id = 0;
+			if (mptcp_addresses_equal(&locals[i].addr, &mpc_addr, locals[i].addr.port))
+				locals[i].addr.id = 0;
 
+			msk->pm.subflows++;
 			i++;
 		}
 	}
@@ -689,21 +695,19 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	 * 'IPADDRANY' local address
 	 */
 	if (!i) {
-		struct mptcp_addr_info local;
-
-		memset(&local, 0, sizeof(local));
-		local.family =
+		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, &local, remote))
+		if (!mptcp_pm_addr_families_match(sk, &locals[i].addr, remote))
 			return 0;
 
 		msk->pm.subflows++;
-		addrs[i++] = local;
+		i++;
 	}
 
 	return i;
@@ -711,7 +715,7 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 
 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 {
-	struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
+	struct mptcp_pm_local locals[MPTCP_PM_ADDR_MAX];
 	struct sock *sk = (struct sock *)msk;
 	unsigned int add_addr_accept_max;
 	struct mptcp_addr_info remote;
@@ -740,13 +744,13 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 	/* connect to the specified remote address, using whatever
 	 * local address the routing configuration will pick.
 	 */
-	nr = fill_local_addresses_vec(msk, &remote, addrs);
+	nr = fill_local_addresses_vec(msk, &remote, locals);
 	if (nr == 0)
 		return;
 
 	spin_unlock_bh(&msk->pm.lock);
 	for (i = 0; i < nr; i++)
-		if (__mptcp_subflow_connect(sk, &addrs[i], &remote) == 0)
+		if (__mptcp_subflow_connect(sk, &locals[i], &remote) == 0)
 			sf_created = true;
 	spin_lock_bh(&msk->pm.lock);
 
@@ -1433,28 +1437,6 @@ int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
 	return ret;
 }
 
-int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
-					    u8 *flags, int *ifindex)
-{
-	struct mptcp_pm_addr_entry *entry;
-	struct sock *sk = (struct sock *)msk;
-	struct net *net = sock_net(sk);
-
-	/* No entries with ID 0 */
-	if (id == 0)
-		return 0;
-
-	rcu_read_lock();
-	entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
-	if (entry) {
-		*flags = entry->flags;
-		*ifindex = entry->ifindex;
-	}
-	rcu_read_unlock();
-
-	return 0;
-}
-
 static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
 				      const struct mptcp_addr_info *addr)
 {
@@ -1672,7 +1654,7 @@ void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list)
 }
 
 /* Called from the in-kernel PM only */
-static void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
+static void mptcp_pm_flush_addrs_and_subflows(struct mptcp_sock *msk,
 					      struct list_head *rm_list)
 {
 	struct mptcp_rm_list alist = { .nr = 0 }, slist = { .nr = 0 };
@@ -1701,7 +1683,7 @@ static void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
 	spin_unlock_bh(&msk->pm.lock);
 }
 
-static void mptcp_nl_remove_addrs_list(struct net *net,
+static void mptcp_nl_flush_addrs_list(struct net *net,
 				      struct list_head *rm_list)
 {
 	long s_slot = 0, s_num = 0;
@@ -1715,7 +1697,7 @@ static void mptcp_nl_remove_addrs_list(struct net *net,
 
 		if (!mptcp_pm_is_userspace(msk)) {
 			lock_sock(sk);
-			mptcp_pm_remove_addrs_and_subflows(msk, rm_list);
+			mptcp_pm_flush_addrs_and_subflows(msk, rm_list);
 			release_sock(sk);
 		}
 
@@ -1756,7 +1738,7 @@ int mptcp_pm_nl_flush_addrs_doit(struct sk_buff *skb, struct genl_info *info)
 	pernet->next_id = 1;
 	bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
 	spin_unlock_bh(&pernet->lock);
-	mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list);
+	mptcp_nl_flush_addrs_list(sock_net(skb->sk), &free_list);
 	synchronize_rcu();
 	__flush_addrs(&free_list);
 	return 0;

net/mptcp/pm_userspace.c

@@ -119,23 +119,6 @@ mptcp_userspace_pm_lookup_addr_by_id(struct mptcp_sock *msk, unsigned int id)
 	return NULL;
 }
 
-int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
-						   unsigned int id,
-						   u8 *flags, int *ifindex)
-{
-	struct mptcp_pm_addr_entry *match;
-
-	spin_lock_bh(&msk->pm.lock);
-	match = mptcp_userspace_pm_lookup_addr_by_id(msk, id);
-	spin_unlock_bh(&msk->pm.lock);
-	if (match) {
-		*flags = match->flags;
-		*ifindex = match->ifindex;
-	}
-
-	return 0;
-}
-
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
 				    struct mptcp_addr_info *skc)
 {
@@ -352,8 +335,9 @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
-	struct mptcp_pm_addr_entry local = { 0 };
+	struct mptcp_pm_addr_entry entry = { 0 };
 	struct mptcp_addr_info addr_r;
+	struct mptcp_pm_local local;
 	struct mptcp_sock *msk;
 	int err = -EINVAL;
 	struct sock *sk;
@@ -379,18 +363,18 @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 		goto create_err;
 	}
 
-	err = mptcp_pm_parse_entry(laddr, info, true, &local);
+	err = mptcp_pm_parse_entry(laddr, info, true, &entry);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
 		goto create_err;
 	}
 
-	if (local.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
+	if (entry.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
 		GENL_SET_ERR_MSG(info, "invalid addr flags");
 		err = -EINVAL;
 		goto create_err;
 	}
-	local.flags |= MPTCP_PM_ADDR_FLAG_SUBFLOW;
+	entry.flags |= MPTCP_PM_ADDR_FLAG_SUBFLOW;
 
 	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
 	if (err < 0) {
@@ -398,27 +382,29 @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 		goto create_err;
 	}
 
-	if (!mptcp_pm_addr_families_match(sk, &local.addr, &addr_r)) {
+	if (!mptcp_pm_addr_families_match(sk, &entry.addr, &addr_r)) {
 		GENL_SET_ERR_MSG(info, "families mismatch");
 		err = -EINVAL;
 		goto create_err;
 	}
 
-	err = mptcp_userspace_pm_append_new_local_addr(msk, &local, false);
+	err = mptcp_userspace_pm_append_new_local_addr(msk, &entry, false);
 	if (err < 0) {
 		GENL_SET_ERR_MSG(info, "did not match address and id");
 		goto create_err;
 	}
 
-	lock_sock(sk);
-
-	err = __mptcp_subflow_connect(sk, &local.addr, &addr_r);
+	local.addr = entry.addr;
+	local.flags = entry.flags;
+	local.ifindex = entry.ifindex;
 
+	lock_sock(sk);
+	err = __mptcp_subflow_connect(sk, &local, &addr_r);
 	release_sock(sk);
 
 	spin_lock_bh(&msk->pm.lock);
 	if (err)
-		mptcp_userspace_pm_delete_local_addr(msk, &local);
+		mptcp_userspace_pm_delete_local_addr(msk, &entry);
 	else
 		msk->pm.subflows++;
 	spin_unlock_bh(&msk->pm.lock);

net/mptcp/protocol.h

@@ -236,6 +236,12 @@ struct mptcp_pm_data {
 	struct mptcp_rm_list rm_list_rx;
 };
 
+struct mptcp_pm_local {
+	struct mptcp_addr_info	addr;
+	u8			flags;
+	int			ifindex;
+};
+
 struct mptcp_pm_addr_entry {
 	struct list_head	list;
 	struct mptcp_addr_info	addr;
@@ -719,7 +725,7 @@ bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
 
 /* called with sk socket lock held */
-int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
+int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_pm_local *local,
 			    const struct mptcp_addr_info *remote);
 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
 				struct socket **new_sock);
@@ -1014,14 +1020,6 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 struct mptcp_pm_add_entry *
 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
 				const struct mptcp_addr_info *addr);
-int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
-					 unsigned int id,
-					 u8 *flags, int *ifindex);
-int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
-					    u8 *flags, int *ifindex);
-int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
-						   unsigned int id,
-						   u8 *flags, int *ifindex);
 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
 int mptcp_pm_nl_set_flags(struct sk_buff *skb, struct genl_info *info);
 int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info);

net/mptcp/subflow.c

@@ -1565,28 +1565,31 @@ void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
 #endif
 }
 
-int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
+int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_pm_local *local,
 			    const struct mptcp_addr_info *remote)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_subflow_context *subflow;
+	int local_id = local->addr.id;
 	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;
 
+	/* The userspace PM sent the request too early? */
 	if (!mptcp_is_fully_established(sk))
 		goto err_out;
 
-	err = mptcp_subflow_create_socket(sk, loc->family, &sf);
-	if (err)
+	err = mptcp_subflow_create_socket(sk, local->addr.family, &sf);
+	if (err) {
+		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNTXCREATSKERR);
+		pr_debug("msk=%p local=%d remote=%d create sock error: %d\n",
+			 msk, local_id, remote_id, err);
 		goto err_out;
+	}
 
 	ssk = sf->sk;
 	subflow = mptcp_subflow_ctx(ssk);
@@ -1594,26 +1597,39 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 		get_random_bytes(&subflow->local_nonce, sizeof(u32));
 	} while (!subflow->local_nonce);
 
-	if (local_id)
+	/* if 'IPADDRANY', the ID will be set later, after the routing */
+	if (local->addr.family == AF_INET) {
+		if (!local->addr.addr.s_addr)
+			local_id = -1;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	} else if (sk->sk_family == AF_INET6) {
+		if (ipv6_addr_any(&local->addr.addr6))
+			local_id = -1;
+#endif
+	}
+
+	if (local_id >= 0)
 		subflow_set_local_id(subflow, local_id);
 
-	mptcp_pm_get_flags_and_ifindex_by_id(msk, local_id,
-					     &flags, &ifindex);
 	subflow->remote_key_valid = 1;
 	subflow->remote_key = READ_ONCE(msk->remote_key);
 	subflow->local_key = READ_ONCE(msk->local_key);
 	subflow->token = msk->token;
-	mptcp_info2sockaddr(loc, &addr, ssk->sk_family);
+	mptcp_info2sockaddr(&local->addr, &addr, ssk->sk_family);
 
 	addrlen = sizeof(struct sockaddr_in);
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 	if (addr.ss_family == AF_INET6)
 		addrlen = sizeof(struct sockaddr_in6);
 #endif
-	ssk->sk_bound_dev_if = ifindex;
+	ssk->sk_bound_dev_if = local->ifindex;
 	err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
-	if (err)
+	if (err) {
+		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNTXBINDERR);
+		pr_debug("msk=%p local=%d remote=%d bind error: %d\n",
+			 msk, local_id, remote_id, err);
 		goto failed;
+	}
 
 	mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL);
 	pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d\n", msk,
@@ -1621,15 +1637,21 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	subflow->remote_token = remote_token;
 	WRITE_ONCE(subflow->remote_id, remote_id);
 	subflow->request_join = 1;
-	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	subflow->request_bkup = !!(local->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
 	subflow->subflow_id = msk->subflow_id++;
 	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
 
 	sock_hold(ssk);
 	list_add_tail(&subflow->node, &msk->conn_list);
 	err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
-	if (err && err != -EINPROGRESS)
+	if (err && err != -EINPROGRESS) {
+		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNTXCONNECTERR);
+		pr_debug("msk=%p local=%d remote=%d connect error: %d\n",
+			 msk, local_id, remote_id, err);
 		goto failed_unlink;
+	}
+
+	MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNTX);
 
 	/* discard the subflow socket */
 	mptcp_sock_graft(ssk, sk->sk_socket);

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

@@ -61,6 +61,16 @@ unset sflags
 unset fastclose
 unset fullmesh
 unset speed
+unset join_csum_ns1
+unset join_csum_ns2
+unset join_fail_nr
+unset join_rst_nr
+unset join_infi_nr
+unset join_corrupted_pkts
+unset join_syn_tx
+unset join_create_err
+unset join_bind_err
+unset join_connect_err
 
 # generated using "nfbpf_compile '(ip && (ip[54] & 0xf0) == 0x30) ||
 #				  (ip6 && (ip6[74] & 0xf0) == 0x30)'"
@@ -196,6 +206,22 @@ print_skip()
 	mptcp_lib_pr_skip "${@}"
 }
 
+# $1: check name; $2: rc
+print_results()
+{
+	local check="${1}"
+	local rc=${2}
+
+	print_check "${check}"
+	if [ ${rc} = ${KSFT_PASS} ]; then
+		print_ok
+	elif [ ${rc} = ${KSFT_SKIP} ]; then
+		print_skip
+	else
+		fail_test "see above"
+	fi
+}
+
 # [ $1: fail msg ]
 mark_as_skipped()
 {
@@ -337,7 +363,7 @@ reset_with_checksum()
 	local ns1_enable=$1
 	local ns2_enable=$2
 
-	reset "checksum test ${1} ${2}" || return 1
+	reset "checksum test ${ns1_enable} ${ns2_enable}" || return 1
 
 	ip netns exec $ns1 sysctl -q net.mptcp.checksum_enabled=$ns1_enable
 	ip netns exec $ns2 sysctl -q net.mptcp.checksum_enabled=$ns2_enable
@@ -839,7 +865,7 @@ chk_cestab_nr()
 	local cestab=$2
 	local count
 
-	print_check "cestab $cestab"
+	print_check "currently established: $cestab"
 	count=$(mptcp_lib_get_counter ${ns} "MPTcpExtMPCurrEstab")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1115,7 +1141,7 @@ chk_csum_nr()
 		csum_ns2=${csum_ns2:1}
 	fi
 
-	print_check "sum"
+	print_check "checksum server"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtDataCsumErr")
 	if [ -n "$count" ] && [ "$count" != "$csum_ns1" ]; then
 		extra_msg+=" ns1=$count"
@@ -1128,7 +1154,8 @@ chk_csum_nr()
 	else
 		print_ok
 	fi
-	print_check "csum"
+
+	print_check "checksum client"
 	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtDataCsumErr")
 	if [ -n "$count" ] && [ "$count" != "$csum_ns2" ]; then
 		extra_msg+=" ns2=$count"
@@ -1153,6 +1180,8 @@ chk_fail_nr()
 	local count
 	local ns_tx=$ns1
 	local ns_rx=$ns2
+	local tx="server"
+	local rx="client"
 	local extra_msg=""
 	local allow_tx_lost=0
 	local allow_rx_lost=0
@@ -1160,7 +1189,8 @@ chk_fail_nr()
 	if [[ $ns_invert = "invert" ]]; then
 		ns_tx=$ns2
 		ns_rx=$ns1
-		extra_msg="invert"
+		tx="client"
+		rx="server"
 	fi
 
 	if [[ "${fail_tx}" = "-"* ]]; then
@@ -1172,10 +1202,10 @@ chk_fail_nr()
 		fail_rx=${fail_rx:1}
 	fi
 
-	print_check "ftx"
+	print_check "fail tx ${tx}"
 	count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMPFailTx")
 	if [ -n "$count" ] && [ "$count" != "$fail_tx" ]; then
-		extra_msg+=",tx=$count"
+		extra_msg+=" tx=$count"
 	fi
 	if [ -z "$count" ]; then
 		print_skip
@@ -1186,10 +1216,10 @@ chk_fail_nr()
 		print_ok
 	fi
 
-	print_check "failrx"
+	print_check "fail rx ${rx}"
 	count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtMPFailRx")
 	if [ -n "$count" ] && [ "$count" != "$fail_rx" ]; then
-		extra_msg+=",rx=$count"
+		extra_msg+=" rx=$count"
 	fi
 	if [ -z "$count" ]; then
 		print_skip
@@ -1211,37 +1241,35 @@ chk_fclose_nr()
 	local count
 	local ns_tx=$ns2
 	local ns_rx=$ns1
-	local extra_msg=""
+	local tx="client"
+	local rx="server"
 
 	if [[ $ns_invert = "invert" ]]; then
 		ns_tx=$ns1
 		ns_rx=$ns2
-		extra_msg="invert"
+		tx="server"
+		rx="client"
 	fi
 
-	print_check "ctx"
+	print_check "fast close tx ${tx}"
 	count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMPFastcloseTx")
 	if [ -z "$count" ]; then
 		print_skip
 	elif [ "$count" != "$fclose_tx" ]; then
-		extra_msg+=",tx=$count"
 		fail_test "got $count MP_FASTCLOSE[s] TX expected $fclose_tx"
 	else
 		print_ok
 	fi
 
-	print_check "fclzrx"
+	print_check "fast close rx ${rx}"
 	count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtMPFastcloseRx")
 	if [ -z "$count" ]; then
 		print_skip
 	elif [ "$count" != "$fclose_rx" ]; then
-		extra_msg+=",rx=$count"
 		fail_test "got $count MP_FASTCLOSE[s] RX expected $fclose_rx"
 	else
 		print_ok
 	fi
-
-	print_info "$extra_msg"
 }
 
 chk_rst_nr()
@@ -1252,15 +1280,17 @@ chk_rst_nr()
 	local count
 	local ns_tx=$ns1
 	local ns_rx=$ns2
-	local extra_msg=""
+	local tx="server"
+	local rx="client"
 
 	if [[ $ns_invert = "invert" ]]; then
 		ns_tx=$ns2
 		ns_rx=$ns1
-		extra_msg="invert"
+		tx="client"
+		rx="server"
 	fi
 
-	print_check "rtx"
+	print_check "reset tx ${tx}"
 	count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMPRstTx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1272,7 +1302,7 @@ chk_rst_nr()
 		print_ok
 	fi
 
-	print_check "rstrx"
+	print_check "reset rx ${rx}"
 	count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtMPRstRx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1283,8 +1313,6 @@ chk_rst_nr()
 	else
 		print_ok
 	fi
-
-	print_info "$extra_msg"
 }
 
 chk_infi_nr()
@@ -1293,7 +1321,7 @@ chk_infi_nr()
 	local infi_rx=$2
 	local count
 
-	print_check "itx"
+	print_check "infi tx client"
 	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtInfiniteMapTx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1303,7 +1331,7 @@ chk_infi_nr()
 		print_ok
 	fi
 
-	print_check "infirx"
+	print_check "infi rx server"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtInfiniteMapRx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1314,17 +1342,66 @@ chk_infi_nr()
 	fi
 }
 
+chk_join_tx_nr()
+{
+	local syn_tx=${join_syn_tx:-0}
+	local create=${join_create_err:-0}
+	local bind=${join_bind_err:-0}
+	local connect=${join_connect_err:-0}
+	local rc=${KSFT_PASS}
+	local count
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTx")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$syn_tx" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx"
+		fail_test "got $count JOIN[s] syn tx expected $syn_tx"
+	fi
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTxCreatSkErr")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$create" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx create socket error"
+		fail_test "got $count JOIN[s] syn tx create socket error expected $create"
+	fi
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTxBindErr")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$bind" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx bind error"
+		fail_test "got $count JOIN[s] syn tx bind error expected $bind"
+	fi
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTxConnectErr")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$connect" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx connect error"
+		fail_test "got $count JOIN[s] syn tx connect error expected $connect"
+	fi
+
+	print_results "join Tx" ${rc}
+}
+
 chk_join_nr()
 {
 	local syn_nr=$1
 	local syn_ack_nr=$2
 	local ack_nr=$3
-	local csum_ns1=${4:-0}
-	local csum_ns2=${5:-0}
-	local fail_nr=${6:-0}
-	local rst_nr=${7:-0}
-	local infi_nr=${8:-0}
-	local corrupted_pkts=${9:-0}
+	local csum_ns1=${join_csum_ns1:-0}
+	local csum_ns2=${join_csum_ns2:-0}
+	local fail_nr=${join_fail_nr:-0}
+	local rst_nr=${join_rst_nr:-0}
+	local infi_nr=${join_infi_nr:-0}
+	local corrupted_pkts=${join_corrupted_pkts:-0}
+	local rc=${KSFT_PASS}
 	local count
 	local with_cookie
 
@@ -1332,43 +1409,44 @@ chk_join_nr()
 		print_info "${corrupted_pkts} corrupted pkts"
 	fi
 
-	print_check "syn"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtMPJoinSynRx")
 	if [ -z "$count" ]; then
-		print_skip
+		rc=${KSFT_SKIP}
 	elif [ "$count" != "$syn_nr" ]; then
-		fail_test "got $count JOIN[s] syn expected $syn_nr"
-	else
-		print_ok
+		rc=${KSFT_FAIL}
+		print_check "syn rx"
+		fail_test "got $count JOIN[s] syn rx expected $syn_nr"
 	fi
 
-	print_check "synack"
 	with_cookie=$(ip netns exec $ns2 sysctl -n net.ipv4.tcp_syncookies)
 	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynAckRx")
 	if [ -z "$count" ]; then
-		print_skip
+		rc=${KSFT_SKIP}
 	elif [ "$count" != "$syn_ack_nr" ]; then
 		# simult connections exceeding the limit with cookie enabled could go up to
 		# synack validation as the conn limit can be enforced reliably only after
 		# the subflow creation
-		if [ "$with_cookie" = 2 ] && [ "$count" -gt "$syn_ack_nr" ] && [ "$count" -le "$syn_nr" ]; then
-			print_ok
-		else
-			fail_test "got $count JOIN[s] synack expected $syn_ack_nr"
+		if [ "$with_cookie" != 2 ] || [ "$count" -le "$syn_ack_nr" ] || [ "$count" -gt "$syn_nr" ]; then
+			rc=${KSFT_FAIL}
+			print_check "synack rx"
+			fail_test "got $count JOIN[s] synack rx expected $syn_ack_nr"
 		fi
-	else
-		print_ok
 	fi
 
-	print_check "ack"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtMPJoinAckRx")
 	if [ -z "$count" ]; then
-		print_skip
+		rc=${KSFT_SKIP}
 	elif [ "$count" != "$ack_nr" ]; then
-		fail_test "got $count JOIN[s] ack expected $ack_nr"
-	else
-		print_ok
+		rc=${KSFT_FAIL}
+		print_check "ack rx"
+		fail_test "got $count JOIN[s] ack rx expected $ack_nr"
 	fi
+
+	print_results "join Rx" ${rc}
+
+	join_syn_tx="${join_syn_tx:-${syn_nr}}" \
+		chk_join_tx_nr
+
 	if $validate_checksum; then
 		chk_csum_nr $csum_ns1 $csum_ns2
 		chk_fail_nr $fail_nr $fail_nr
@@ -1429,19 +1507,21 @@ chk_add_nr()
 	local mis_ack_nr=0
 	local ns_tx=$ns1
 	local ns_rx=$ns2
-	local extra_msg=""
+	local tx=""
+	local rx=""
 	local count
 	local timeout
 
 	if [[ $ns_invert = "invert" ]]; then
 		ns_tx=$ns2
 		ns_rx=$ns1
-		extra_msg="invert"
+		tx=" client"
+		rx=" server"
 	fi
 
 	timeout=$(ip netns exec ${ns_tx} sysctl -n net.mptcp.add_addr_timeout)
 
-	print_check "add"
+	print_check "add addr rx${rx}"
 	count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtAddAddr")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1453,7 +1533,7 @@ chk_add_nr()
 		print_ok
 	fi
 
-	print_check "echo"
+	print_check "add addr echo rx${tx}"
 	count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtEchoAdd")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1464,7 +1544,7 @@ chk_add_nr()
 	fi
 
 	if [ $port_nr -gt 0 ]; then
-		print_check "pt"
+		print_check "add addr rx with port${rx}"
 		count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtPortAdd")
 		if [ -z "$count" ]; then
 			print_skip
@@ -1474,7 +1554,7 @@ chk_add_nr()
 			print_ok
 		fi
 
-		print_check "syn"
+		print_check "syn rx port${tx}"
 		count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMPJoinPortSynRx")
 		if [ -z "$count" ]; then
 			print_skip
@@ -1485,7 +1565,7 @@ chk_add_nr()
 			print_ok
 		fi
 
-		print_check "synack"
+		print_check "synack rx port${rx}"
 		count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtMPJoinPortSynAckRx")
 		if [ -z "$count" ]; then
 			print_skip
@@ -1496,7 +1576,7 @@ chk_add_nr()
 			print_ok
 		fi
 
-		print_check "ack"
+		print_check "ack rx port${tx}"
 		count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMPJoinPortAckRx")
 		if [ -z "$count" ]; then
 			print_skip
@@ -1507,7 +1587,7 @@ chk_add_nr()
 			print_ok
 		fi
 
-		print_check "syn"
+		print_check "syn rx port mismatch${tx}"
 		count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMismatchPortSynRx")
 		if [ -z "$count" ]; then
 			print_skip
@@ -1518,7 +1598,7 @@ chk_add_nr()
 			print_ok
 		fi
 
-		print_check "ack"
+		print_check "ack rx port mismatch${tx}"
 		count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMismatchPortAckRx")
 		if [ -z "$count" ]; then
 			print_skip
@@ -1529,8 +1609,6 @@ chk_add_nr()
 			print_ok
 		fi
 	fi
-
-	print_info "$extra_msg"
 }
 
 chk_add_tx_nr()
@@ -1542,7 +1620,7 @@ chk_add_tx_nr()
 
 	timeout=$(ip netns exec $ns1 sysctl -n net.mptcp.add_addr_timeout)
 
-	print_check "add TX"
+	print_check "add addr tx"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtAddAddrTx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1554,7 +1632,7 @@ chk_add_tx_nr()
 		print_ok
 	fi
 
-	print_check "echo TX"
+	print_check "add addr echo tx"
 	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtEchoAddTx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1574,6 +1652,8 @@ chk_rm_nr()
 	local count
 	local addr_ns=$ns1
 	local subflow_ns=$ns2
+	local addr="server"
+	local subflow="client"
 	local extra_msg=""
 
 	shift 2
@@ -1583,16 +1663,14 @@ chk_rm_nr()
 		shift
 	done
 
-	if [ -z $invert ]; then
-		addr_ns=$ns1
-		subflow_ns=$ns2
-	elif [ $invert = "true" ]; then
+	if [ "$invert" = "true" ]; then
 		addr_ns=$ns2
 		subflow_ns=$ns1
-		extra_msg="invert"
+		addr="client"
+		subflow="server"
 	fi
 
-	print_check "rm"
+	print_check "rm addr rx ${addr}"
 	count=$(mptcp_lib_get_counter ${addr_ns} "MPTcpExtRmAddr")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1602,7 +1680,7 @@ chk_rm_nr()
 		print_ok
 	fi
 
-	print_check "rmsf"
+	print_check "rm subflow ${subflow}"
 	count=$(mptcp_lib_get_counter ${subflow_ns} "MPTcpExtRmSubflow")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1616,7 +1694,7 @@ chk_rm_nr()
 		count=$((count + cnt))
 		if [ "$count" != "$rm_subflow_nr" ]; then
 			suffix="$count in [$rm_subflow_nr:$((rm_subflow_nr*2))]"
-			extra_msg+=" simult"
+			extra_msg="simult"
 		fi
 		if [ $count -ge "$rm_subflow_nr" ] && \
 		   [ "$count" -le "$((rm_subflow_nr *2 ))" ]; then
@@ -1637,7 +1715,7 @@ chk_rm_tx_nr()
 {
 	local rm_addr_tx_nr=$1
 
-	print_check "rm TX"
+	print_check "rm addr tx client"
 	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtRmAddrTx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1656,7 +1734,7 @@ chk_prio_nr()
 	local mpj_syn_ack=$4
 	local count
 
-	print_check "ptx"
+	print_check "mp_prio tx server"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtMPPrioTx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1666,7 +1744,7 @@ chk_prio_nr()
 		print_ok
 	fi
 
-	print_check "prx"
+	print_check "mp_prio rx client"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtMPPrioRx")
 	if [ -z "$count" ]; then
 		print_skip
@@ -1909,8 +1987,10 @@ subflows_error_tests()
 		pm_nl_set_limits $ns1 0 1
 		pm_nl_set_limits $ns2 0 1
 		pm_nl_add_endpoint $ns2 10.0.1.2 flags subflow
+		pm_nl_add_endpoint $ns2 10.0.12.2 flags subflow
 		speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_bind_err=1 \
 			chk_join_nr 0 0 0
 	fi
 
@@ -1923,6 +2003,7 @@ subflows_error_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 flags subflow
 		speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 	fi
 
@@ -1935,6 +2016,7 @@ subflows_error_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 flags subflow
 		speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 	fi
 
@@ -1956,6 +2038,7 @@ subflows_error_tests()
 
 		# additional subflow could be created only if the PM select
 		# the later endpoint, skipping the already used one
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 	fi
 }
@@ -2042,6 +2125,7 @@ signal_address_tests()
 		pm_nl_add_endpoint $ns1 10.0.14.1 flags signal
 		pm_nl_set_limits $ns2 3 3
 		run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=3 \
 			chk_join_nr 1 1 1
 		chk_add_nr 3 3
 	fi
@@ -2210,6 +2294,7 @@ add_addr_timeout_tests()
 		pm_nl_set_limits $ns2 2 2
 		speed=10 \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 		chk_add_nr 8 0
 	fi
@@ -2310,6 +2395,7 @@ remove_tests()
 		pm_nl_set_limits $ns2 2 2
 		addr_nr_ns1=-3 speed=10 \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 join_connect_err=1 \
 			chk_join_nr 1 1 1
 		chk_add_nr 3 3
 		chk_rm_nr 3 1 invert
@@ -2375,6 +2461,7 @@ remove_tests()
 		pm_nl_set_limits $ns2 3 3
 		addr_nr_ns1=-8 speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=3 \
 			chk_join_nr 1 1 1
 		chk_add_nr 3 3
 		chk_rm_nr 3 1 invert
@@ -2945,37 +3032,16 @@ syncookies_tests()
 
 checksum_tests()
 {
-	# checksum test 0 0
-	if reset_with_checksum 0 0; then
-		pm_nl_set_limits $ns1 0 1
-		pm_nl_set_limits $ns2 0 1
-		run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 0 0 0
-	fi
-
-	# checksum test 1 1
-	if reset_with_checksum 1 1; then
-		pm_nl_set_limits $ns1 0 1
-		pm_nl_set_limits $ns2 0 1
-		run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 0 0 0
-	fi
-
-	# checksum test 0 1
-	if reset_with_checksum 0 1; then
-		pm_nl_set_limits $ns1 0 1
-		pm_nl_set_limits $ns2 0 1
-		run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 0 0 0
-	fi
-
-	# checksum test 1 0
-	if reset_with_checksum 1 0; then
+	local checksum_enable
+	for checksum_enable in "0 0" "1 1" "0 1" "1 0"; do
+		# checksum test 0 0, 1 1, 0 1, 1 0
+		if reset_with_checksum ${checksum_enable}; then
 			pm_nl_set_limits $ns1 0 1
 			pm_nl_set_limits $ns2 0 1
 			run_tests $ns1 $ns2 10.0.1.1
 			chk_join_nr 0 0 0
 		fi
+	done
 }
 
 deny_join_id0_tests()
@@ -3164,7 +3230,8 @@ fastclose_tests()
 		MPTCP_LIB_SUBTEST_FLAKY=1
 		test_linkfail=1024 fastclose=server \
 			run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 0 0 0 0 0 0 1
+		join_rst_nr=1 \
+			chk_join_nr 0 0 0
 		chk_fclose_nr 1 1 invert
 		chk_rst_nr 1 1
 	fi
@@ -3183,7 +3250,10 @@ fail_tests()
 		MPTCP_LIB_SUBTEST_FLAKY=1
 		test_linkfail=128 \
 			run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 0 0 0 +1 +0 1 0 1 "$(pedit_action_pkts)"
+		join_csum_ns1=+1 join_csum_ns2=+0 \
+			join_fail_nr=1 join_rst_nr=0 join_infi_nr=1 \
+			join_corrupted_pkts="$(pedit_action_pkts)" \
+			chk_join_nr 0 0 0
 		chk_fail_nr 1 -1 invert
 	fi
 
@@ -3196,7 +3266,10 @@ fail_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 dev ns2eth2 flags subflow
 		test_linkfail=1024 \
 			run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 1 1 1 1 0 1 1 0 "$(pedit_action_pkts)"
+		join_csum_ns1=1 join_csum_ns2=0 \
+			join_fail_nr=1 join_rst_nr=1 join_infi_nr=0 \
+			join_corrupted_pkts="$(pedit_action_pkts)" \
+			chk_join_nr 1 1 1
 	fi
 }
 
@@ -3448,8 +3521,8 @@ userspace_tests()
 	   continue_if mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 		set_userspace_pm $ns1
 		pm_nl_set_limits $ns2 2 2
-		speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 		wait_mpj $ns1
 		userspace_pm_add_addr $ns1 10.0.2.1 10
@@ -3481,8 +3554,8 @@ userspace_tests()
 	   continue_if mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 		set_userspace_pm $ns2
 		pm_nl_set_limits $ns1 0 1
-		speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 		wait_mpj $ns2
 		userspace_pm_add_sf $ns2 10.0.3.2 20
@@ -3509,8 +3582,8 @@ userspace_tests()
 	   continue_if mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 		set_userspace_pm $ns2
 		pm_nl_set_limits $ns1 0 1
-		speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 		wait_mpj $ns2
 		chk_mptcp_info subflows 0 subflows 0
@@ -3530,8 +3603,8 @@ userspace_tests()
 	   continue_if mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 		set_userspace_pm $ns2
 		pm_nl_set_limits $ns1 0 1
-		speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 		wait_mpj $ns2
 		userspace_pm_add_sf $ns2 10.0.3.2 20
@@ -3554,8 +3627,8 @@ userspace_tests()
 	   continue_if mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 		set_userspace_pm $ns1
 		pm_nl_set_limits $ns2 1 1
-		speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 		wait_mpj $ns1
 		userspace_pm_add_addr $ns1 10.0.2.1 10
@@ -3585,8 +3658,8 @@ endpoint_tests()
 		pm_nl_set_limits $ns1 2 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
-		speed=slow \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ speed=slow \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 
 		wait_mpj $ns1
@@ -3612,8 +3685,8 @@ endpoint_tests()
 		pm_nl_set_limits $ns2 0 3
 		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow
 		pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow
-		test_linkfail=4 speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ test_linkfail=4 speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 
 		wait_mpj $ns2
@@ -3675,6 +3748,7 @@ endpoint_tests()
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_ESTABLISHED 6
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_CLOSED 5 # one has been closed before estab
 
+		join_syn_tx=7 \
 			chk_join_nr 6 6 6
 		chk_rm_nr 4 4
 	fi
@@ -3688,8 +3762,8 @@ endpoint_tests()
 		# broadcast IP: no packet for this address will be received on ns1
 		pm_nl_add_endpoint $ns1 224.0.0.1 id 2 flags signal
 		pm_nl_add_endpoint $ns1 10.0.1.1 id 42 flags signal
-		test_linkfail=4 speed=5 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ test_linkfail=4 speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 
 		wait_mpj $ns2
@@ -3747,6 +3821,7 @@ endpoint_tests()
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_ESTABLISHED 5
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_CLOSED 3
 
+		join_connect_err=1 \
 			chk_join_nr 5 5 5
 		chk_add_nr 6 6
 		chk_rm_nr 4 3 invert
@@ -3760,8 +3835,8 @@ endpoint_tests()
 		# broadcast IP: no packet for this address will be received on ns1
 		pm_nl_add_endpoint $ns1 224.0.0.1 id 2 flags signal
 		pm_nl_add_endpoint $ns2 10.0.3.2 id 3 flags subflow
-		test_linkfail=4 speed=20 \
-			run_tests $ns1 $ns2 10.0.1.1 &
+		{ test_linkfail=4 speed=20 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
 		local tests_pid=$!
 
 		wait_attempt_fail $ns2
@@ -3778,6 +3853,7 @@ endpoint_tests()
 		wait_mpj $ns2
 		mptcp_lib_kill_wait $tests_pid
 
+		join_syn_tx=3 join_connect_err=1 \
 			chk_join_nr 2 2 2
 		chk_add_nr 2 2
 		chk_rm_nr 1 0 invert

tools/testing/selftests/net/mptcp/pm_nl_ctl.c

@@ -19,12 +19,6 @@
 
 #include "linux/mptcp.h"
 
-#ifndef MPTCP_PM_NAME
-#define MPTCP_PM_NAME		"mptcp_pm"
-#endif
-#ifndef MPTCP_PM_EVENTS
-#define MPTCP_PM_EVENTS		"mptcp_pm_events"
-#endif
 #ifndef IPPROTO_MPTCP
 #define IPPROTO_MPTCP 262
 #endif
@@ -116,7 +110,7 @@ static int capture_events(int fd, int event_group)
 
 	if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
 		       &event_group, sizeof(event_group)) < 0)
-		error(1, errno, "could not join the " MPTCP_PM_EVENTS " mcast group");
+		error(1, errno, "could not join the " MPTCP_PM_EV_GRP_NAME " mcast group");
 
 	do {
 		FD_ZERO(&rfds);
@@ -288,7 +282,7 @@ static int genl_parse_getfamily(struct nlmsghdr *nlh, int *pm_family,
 					if (grp->rta_type == CTRL_ATTR_MCAST_GRP_ID)
 						*events_mcast_grp = *(__u32 *)RTA_DATA(grp);
 					else if (grp->rta_type == CTRL_ATTR_MCAST_GRP_NAME &&
-						 !strcmp(RTA_DATA(grp), MPTCP_PM_EVENTS))
+						 !strcmp(RTA_DATA(grp), MPTCP_PM_EV_GRP_NAME))
 						got_events_grp = 1;
 
 					grp = RTA_NEXT(grp, grp_len);