Merge branch 'mptcp-add-mixed-v4-v6-support-for-the-in-kernel-pm'

Matthieu Baerts says:

====================
mptcp: add mixed v4/v6 support for the in-kernel PM

Before these patches, the in-kernel Path-Manager would not allow, for
the same MPTCP connection, having a mix of subflows in v4 and v6.

MPTCP's RFC 8684 doesn't forbid that and it is even recommended to do so
as the path in v4 and v6 are likely different. Some networks are also
v4 or v6 only, we cannot assume they all have both v4 and v6 support.

Patch 1 then removes this artificial constraint in the in-kernel PM
currently enforcing there are no mixed subflows in place, either in
address announcement or in subflow creation areas.

Patch 2 makes sure the sk_ipv6only attribute is also propagated to
subflows, just in case a new PM wouldn't respect it.

Some selftests have also been added for the in-kernel PM (patch 3).

Patches 4 to 8 are just some cleanups and small improvements in the
printed messages in the userspace PM. It is not linked to the rest but
identified when working on a related patch modifying this selftest,
already in -net:

  commit 4656d72c1efa ("selftests: mptcp: userspace: validate v4-v6 subflows mix")
---
====================

Link: https://lore.kernel.org/r/20230123-upstream-net-next-pm-v4-v6-v1-0-43fac502bfbf@tessares.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

5 files changed, 171 insertions, 99 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index b5505b8167f9..db07cc5b4fcb 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -152,7 +152,6 @@ static struct mptcp_pm_addr_entry *
 select_local_address(const struct pm_nl_pernet *pernet,
 		     const struct mptcp_sock *msk)
 {
-	const struct sock *sk = (const struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry, *ret = NULL;
 
 	msk_owned_by_me(msk);
@@ -165,16 +164,6 @@ select_local_address(const struct pm_nl_pernet *pernet,
 		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 			continue;
 
-		if (entry->addr.family != sk->sk_family) {
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-			if ((entry->addr.family == AF_INET &&
-			     !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
-			    (sk->sk_family == AF_INET &&
-			     !ipv6_addr_v4mapped(&entry->addr.addr6)))
-#endif
-				continue;
-		}
-
 		ret = entry;
 		break;
 	}
@@ -423,7 +412,9 @@ static bool lookup_address_in_vec(const struct mptcp_addr_info *addrs, unsigned
 /* 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, bool fullmesh,
+static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk,
+					      struct mptcp_addr_info *local,
+					      bool fullmesh,
 					      struct mptcp_addr_info *addrs)
 {
 	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
@@ -443,6 +434,9 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullm
 		if (deny_id0)
 			return 0;
 
+		if (!mptcp_pm_addr_families_match(sk, local, &remote))
+			return 0;
+
 		msk->pm.subflows++;
 		addrs[i++] = remote;
 	} else {
@@ -453,6 +447,9 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullm
 			if (deny_id0 && !addrs[i].id)
 				continue;
 
+			if (!mptcp_pm_addr_families_match(sk, local, &addrs[i]))
+				continue;
+
 			if (!lookup_address_in_vec(addrs, i, &addrs[i]) &&
 			    msk->pm.subflows < subflows_max) {
 				msk->pm.subflows++;
@@ -603,9 +600,11 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 		fullmesh = !!(local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
 
 		msk->pm.local_addr_used++;
-		nr = fill_remote_addresses_vec(msk, fullmesh, addrs);
-		if (nr)
-			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+		__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+		nr = fill_remote_addresses_vec(msk, &local->addr, fullmesh, addrs);
+		if (nr == 0)
+			continue;
+
 		spin_unlock_bh(&msk->pm.lock);
 		for (i = 0; i < nr; i++)
 			__mptcp_subflow_connect(sk, &local->addr, &addrs[i]);
@@ -628,11 +627,11 @@ static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
  * and return the array size.
  */
 static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
+					     struct mptcp_addr_info *remote,
 					     struct mptcp_addr_info *addrs)
 {
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
-	struct mptcp_addr_info local;
 	struct pm_nl_pernet *pernet;
 	unsigned int subflows_max;
 	int i = 0;
@@ -645,15 +644,8 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
 			continue;
 
-		if (entry->addr.family != sk->sk_family) {
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-			if ((entry->addr.family == AF_INET &&
-			     !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
-			    (sk->sk_family == AF_INET &&
-			     !ipv6_addr_v4mapped(&entry->addr.addr6)))
-#endif
-				continue;
-		}
+		if (!mptcp_pm_addr_families_match(sk, &entry->addr, remote))
+			continue;
 
 		if (msk->pm.subflows < subflows_max) {
 			msk->pm.subflows++;
@@ -666,8 +658,18 @@ 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 = msk->pm.remote.family;
+		local.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))
+			return 0;
 
 		msk->pm.subflows++;
 		addrs[i++] = local;
@@ -706,7 +708,9 @@ 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, addrs);
+	nr = fill_local_addresses_vec(msk, &remote, addrs);
+	if (nr == 0)
+		return;
 
 	msk->pm.add_addr_accepted++;
 	if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index ea6ad9da7493..a02d3cbf2a1b 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -59,8 +59,8 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 		 */
 		e = sock_kmalloc(sk, sizeof(*e), GFP_ATOMIC);
 		if (!e) {
-			spin_unlock_bh(&msk->pm.lock);
-			return -ENOMEM;
+			ret = -ENOMEM;
+			goto append_err;
 		}
 
 		*e = *entry;
@@ -74,6 +74,7 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 		ret = entry->addr.id;
 	}
 
+append_err:
 	spin_unlock_bh(&msk->pm.lock);
 	return ret;
 }
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 582ed93bcc8a..9986681aaf40 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -1255,6 +1255,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 	ssk->sk_priority = sk->sk_priority;
 	ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
 	ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
+	ssk->sk_ipv6only = sk->sk_ipv6only;
 	__ip_sock_set_tos(ssk, inet_sk(sk)->tos);
 
 	if (sk->sk_userlocks & tx_rx_locks) {
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index d11d3d566608..387abdcec011 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -774,24 +774,17 @@ do_transfer()
 		addr_nr_ns2=${addr_nr_ns2:9}
 	fi
 
-	local local_addr
-	if is_v6 "${connect_addr}"; then
-		local_addr="::"
-	else
-		local_addr="0.0.0.0"
-	fi
-
 	extra_srv_args="$extra_args $extra_srv_args"
 	if [ "$test_link_fail" -gt 1 ];then
 		timeout ${timeout_test} \
 			ip netns exec ${listener_ns} \
 				./mptcp_connect -t ${timeout_poll} -l -p $port -s ${srv_proto} \
-					$extra_srv_args ${local_addr} < "$sinfail" > "$sout" &
+					$extra_srv_args "::" < "$sinfail" > "$sout" &
 	else
 		timeout ${timeout_test} \
 			ip netns exec ${listener_ns} \
 				./mptcp_connect -t ${timeout_poll} -l -p $port -s ${srv_proto} \
-					$extra_srv_args ${local_addr} < "$sin" > "$sout" &
+					$extra_srv_args "::" < "$sin" > "$sout" &
 	fi
 	local spid=$!
 
@@ -2448,6 +2441,47 @@ v4mapped_tests()
 	fi
 }
 
+mixed_tests()
+{
+	if reset "IPv4 sockets do not use IPv6 addresses"; then
+		pm_nl_set_limits $ns1 0 1
+		pm_nl_set_limits $ns2 1 1
+		pm_nl_add_endpoint $ns1 dead:beef:2::1 flags signal
+		run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow
+		chk_join_nr 0 0 0
+	fi
+
+	# Need an IPv6 mptcp socket to allow subflows of both families
+	if reset "simult IPv4 and IPv6 subflows"; then
+		pm_nl_set_limits $ns1 0 1
+		pm_nl_set_limits $ns2 1 1
+		pm_nl_add_endpoint $ns1 10.0.1.1 flags signal
+		run_tests $ns1 $ns2 dead:beef:2::1 0 0 0 slow
+		chk_join_nr 1 1 1
+	fi
+
+	# cross families subflows will not be created even in fullmesh mode
+	if reset "simult IPv4 and IPv6 subflows, fullmesh 1x1"; then
+		pm_nl_set_limits $ns1 0 4
+		pm_nl_set_limits $ns2 1 4
+		pm_nl_add_endpoint $ns2 dead:beef:2::2 flags subflow,fullmesh
+		pm_nl_add_endpoint $ns1 10.0.1.1 flags signal
+		run_tests $ns1 $ns2 dead:beef:2::1 0 0 0 slow
+		chk_join_nr 1 1 1
+	fi
+
+	# fullmesh still tries to create all the possibly subflows with
+	# matching family
+	if reset "simult IPv4 and IPv6 subflows, fullmesh 2x2"; then
+		pm_nl_set_limits $ns1 0 4
+		pm_nl_set_limits $ns2 2 4
+		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
+		pm_nl_add_endpoint $ns1 dead:beef:2::1 flags signal
+		run_tests $ns1 $ns2 dead:beef:1::1 0 0 fullmesh_1 slow
+		chk_join_nr 4 4 4
+	fi
+}
+
 backup_tests()
 {
 	# single subflow, backup
@@ -3120,6 +3154,7 @@ all_tests_sorted=(
 	a@add_tests
 	6@ipv6_tests
 	4@v4mapped_tests
+	M@mixed_tests
 	b@backup_tests
 	p@add_addr_ports_tests
 	k@syncookies_tests
diff --git a/tools/testing/selftests/net/mptcp/userspace_pm.sh b/tools/testing/selftests/net/mptcp/userspace_pm.sh
index ab2d581f28a1..66c5be25c13d 100755
--- a/tools/testing/selftests/net/mptcp/userspace_pm.sh
+++ b/tools/testing/selftests/net/mptcp/userspace_pm.sh
@@ -43,41 +43,40 @@ rndh=$(printf %x "$sec")-$(mktemp -u XXXXXX)
 ns1="ns1-$rndh"
 ns2="ns2-$rndh"
 
+print_title()
+{
+	stdbuf -o0 -e0 printf "INFO: %s\n" "${1}"
+}
+
 kill_wait()
 {
+	[ $1 -eq 0 ] && return 0
+
+	kill -SIGUSR1 $1 > /dev/null 2>&1
 	kill $1 > /dev/null 2>&1
 	wait $1 2>/dev/null
 }
 
 cleanup()
 {
-	echo "cleanup"
-
-	rm -rf $file $client_evts $server_evts
+	print_title "Cleanup"
 
 	# Terminate the MPTCP connection and related processes
-	if [ $client4_pid -ne 0 ]; then
-		kill -SIGUSR1 $client4_pid > /dev/null 2>&1
-	fi
-	if [ $server4_pid -ne 0 ]; then
-		kill_wait $server4_pid
-	fi
-	if [ $client6_pid -ne 0 ]; then
-		kill -SIGUSR1 $client6_pid > /dev/null 2>&1
-	fi
-	if [ $server6_pid -ne 0 ]; then
-		kill_wait $server6_pid
-	fi
-	if [ $server_evts_pid -ne 0 ]; then
-		kill_wait $server_evts_pid
-	fi
-	if [ $client_evts_pid -ne 0 ]; then
-		kill_wait $client_evts_pid
-	fi
+	local pid
+	for pid in $client4_pid $server4_pid $client6_pid $server6_pid\
+		   $server_evts_pid $client_evts_pid
+	do
+		kill_wait $pid
+	done
+
 	local netns
 	for netns in "$ns1" "$ns2" ;do
 		ip netns del "$netns"
 	done
+
+	rm -rf $file $client_evts $server_evts
+
+	stdbuf -o0 -e0 printf "Done\n"
 }
 
 trap cleanup EXIT
@@ -108,6 +107,7 @@ ip -net "$ns2" addr add dead:beef:1::2/64 dev ns2eth1 nodad
 ip -net "$ns2" addr add dead:beef:2::2/64 dev ns2eth1 nodad
 ip -net "$ns2" link set ns2eth1 up
 
+print_title "Init"
 stdbuf -o0 -e0 printf "Created network namespaces ns1, ns2         \t\t\t[OK]\n"
 
 make_file()
@@ -193,11 +193,16 @@ make_connection()
 	server_serverside=$(grep "type:1," "$server_evts" |
 			    sed --unbuffered -n 's/.*\(server_side:\)\([[:digit:]]*\).*$/\2/p;q')
 
+	stdbuf -o0 -e0 printf "Established IP%s MPTCP Connection ns2 => ns1    \t\t" $is_v6
 	if [ "$client_token" != "" ] && [ "$server_token" != "" ] && [ "$client_serverside" = 0 ] &&
 		   [ "$server_serverside" = 1 ]
 	then
-		stdbuf -o0 -e0 printf "Established IP%s MPTCP Connection ns2 => ns1    \t\t[OK]\n" $is_v6
+		stdbuf -o0 -e0 printf "[OK]\n"
 	else
+		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "\tExpected tokens (c:%s - s:%s) and server (c:%d - s:%d)\n" \
+			"${client_token}" "${server_token}" \
+			"${client_serverside}" "${server_serverside}"
 		exit 1
 	fi
 
@@ -217,6 +222,48 @@ make_connection()
 	fi
 }
 
+# $1: var name ; $2: prev ret
+check_expected_one()
+{
+	local var="${1}"
+	local exp="e_${var}"
+	local prev_ret="${2}"
+
+	if [ "${!var}" = "${!exp}" ]
+	then
+		return 0
+	fi
+
+	if [ "${prev_ret}" = "0" ]
+	then
+		stdbuf -o0 -e0 printf "[FAIL]\n"
+	fi
+
+	stdbuf -o0 -e0 printf "\tExpected value for '%s': '%s', got '%s'.\n" \
+		"${var}" "${!var}" "${!exp}"
+	return 1
+}
+
+# $@: all var names to check
+check_expected()
+{
+	local ret=0
+	local var
+
+	for var in "${@}"
+	do
+		check_expected_one "${var}" "${ret}" || ret=1
+	done
+
+	if [ ${ret} -eq 0 ]
+	then
+		stdbuf -o0 -e0 printf "[OK]\n"
+		return 0
+	fi
+
+	exit 1
+}
+
 verify_announce_event()
 {
 	local evt=$1
@@ -242,19 +289,14 @@ verify_announce_event()
 	fi
 	dport=$(sed --unbuffered -n 's/.*\(dport:\)\([[:digit:]]*\).*$/\2/p;q' "$evt")
 	id=$(sed --unbuffered -n 's/.*\(rem_id:\)\([[:digit:]]*\).*$/\2/p;q' "$evt")
-	if [ "$type" = "$e_type" ] && [ "$token" = "$e_token" ] &&
-		   [ "$addr" = "$e_addr" ] && [ "$dport" = "$e_dport" ] &&
-		   [ "$id" = "$e_id" ]
-	then
-		stdbuf -o0 -e0 printf "[OK]\n"
-		return 0
-	fi
-	stdbuf -o0 -e0 printf "[FAIL]\n"
-	exit 1
+
+	check_expected "type" "token" "addr" "dport" "id"
 }
 
 test_announce()
 {
+	print_title "Announce tests"
+
 	# Capture events on the network namespace running the server
 	:>"$server_evts"
 
@@ -270,7 +312,7 @@ test_announce()
 	then
 		stdbuf -o0 -e0 printf "[OK]\n"
 	else
-		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "[FAIL]\n\ttype defined: %s\n" "${type}"
 		exit 1
 	fi
 
@@ -347,18 +389,14 @@ verify_remove_event()
 	type=$(sed --unbuffered -n 's/.*\(type:\)\([[:digit:]]*\).*$/\2/p;q' "$evt")
 	token=$(sed --unbuffered -n 's/.*\(token:\)\([[:digit:]]*\).*$/\2/p;q' "$evt")
 	id=$(sed --unbuffered -n 's/.*\(rem_id:\)\([[:digit:]]*\).*$/\2/p;q' "$evt")
-	if [ "$type" = "$e_type" ] && [ "$token" = "$e_token" ] &&
-		   [ "$id" = "$e_id" ]
-	then
-		stdbuf -o0 -e0 printf "[OK]\n"
-		return 0
-	fi
-	stdbuf -o0 -e0 printf "[FAIL]\n"
-	exit 1
+
+	check_expected "type" "token" "id"
 }
 
 test_remove()
 {
+	print_title "Remove tests"
+
 	# Capture events on the network namespace running the server
 	:>"$server_evts"
 
@@ -507,20 +545,13 @@ verify_subflow_events()
 		daddr=$(sed --unbuffered -n 's/.*\(daddr4:\)\([0-9.]*\).*$/\2/p;q' "$evt")
 	fi
 
-	if [ "$type" = "$e_type" ] && [ "$token" = "$e_token" ] &&
-		   [ "$daddr" = "$e_daddr" ] && [ "$e_dport" = "$dport" ] &&
-		   [ "$family" = "$e_family" ] && [ "$saddr" = "$e_saddr" ] &&
-		   [ "$e_locid" = "$locid" ] && [ "$e_remid" = "$remid" ]
-	then
-		stdbuf -o0 -e0 printf "[OK]\n"
-		return 0
-	fi
-	stdbuf -o0 -e0 printf "[FAIL]\n"
-	exit 1
+	check_expected "type" "token" "daddr" "dport" "family" "saddr" "locid" "remid"
 }
 
 test_subflows()
 {
+	print_title "Subflows v4 or v6 only tests"
+
 	# Capture events on the network namespace running the server
 	:>"$server_evts"
 
@@ -754,6 +785,8 @@ test_subflows()
 
 test_subflows_v4_v6_mix()
 {
+	print_title "Subflows v4 and v6 mix tests"
+
 	# Attempt to add a listener at 10.0.2.1:<subflow-port>
 	ip netns exec "$ns1" ./pm_nl_ctl listen 10.0.2.1\
 	   $app6_port > /dev/null 2>&1 &
@@ -800,6 +833,8 @@ test_subflows_v4_v6_mix()
 
 test_prio()
 {
+	print_title "Prio tests"
+
 	local count
 
 	# Send MP_PRIO signal from client to server machine
@@ -811,7 +846,7 @@ test_prio()
 	count=$(ip netns exec "$ns2" nstat -as | grep MPTcpExtMPPrioTx | awk '{print $2}')
 	[ -z "$count" ] && count=0
 	if [ $count != 1 ]; then
-		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "[FAIL]\n\tCount != 1: %d\n" "${count}"
 		exit 1
 	else
 		stdbuf -o0 -e0 printf "[OK]\n"
@@ -822,7 +857,7 @@ test_prio()
 	count=$(ip netns exec "$ns1" nstat -as | grep MPTcpExtMPPrioRx | awk '{print $2}')
 	[ -z "$count" ] && count=0
 	if [ $count != 1 ]; then
-		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "[FAIL]\n\tCount != 1: %d\n" "${count}"
 		exit 1
 	else
 		stdbuf -o0 -e0 printf "[OK]\n"
@@ -863,19 +898,13 @@ verify_listener_events()
 			sed --unbuffered -n 's/.*\(saddr4:\)\([0-9.]*\).*$/\2/p;q')
 	fi
 
-	if [ $type ] && [ $type = $e_type ] &&
-	   [ $family ] && [ $family = $e_family ] &&
-	   [ $saddr ] && [ $saddr = $e_saddr ] &&
-	   [ $sport ] && [ $sport = $e_sport ]; then
-		stdbuf -o0 -e0 printf "[OK]\n"
-		return 0
-	fi
-	stdbuf -o0 -e0 printf "[FAIL]\n"
-	exit 1
+	check_expected "type" "family" "saddr" "sport"
 }
 
 test_listener()
 {
+	print_title "Listener tests"
+
 	# Capture events on the network namespace running the client
 	:>$client_evts
 
@@ -902,8 +931,10 @@ test_listener()
 	verify_listener_events $client_evts $LISTENER_CLOSED $AF_INET 10.0.2.2 $client4_port
 }
 
+print_title "Make connections"
 make_connection
 make_connection "v6"
+
 test_announce
 test_remove
 test_subflows