Merge branch 'mptcp-ipv4-mapped-ipv6-addressing-for-subflows'

Mat Martineau says:

====================
MPTCP: IPv4-mapped IPv6 addressing for subflows

This patch series from the MPTCP tree adds support for IPv4-mapped IPv6
addressing that was missing when multiple subflows were first
implemented.

Patches 1 and 2 handle the conversion and comparison of the mapped
addresses.

Patch 3 contains a minor refactor in the path manager's handling of
addresses.

Patches 4 and 5 add selftests for the new functionality and adjust the
selftest timeout.
====================

Link: https://lore.kernel.org/r/20210125185904.6997-1-mathew.j.martineau@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 120 insertions, 20 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 9b1f6298bbdba..83976b9ee99bc 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -60,15 +60,20 @@ static bool addresses_equal(const struct mptcp_addr_info *a,
 {
 	bool addr_equals = false;
 
-	if (a->family != b->family)
-		return false;
-
-	if (a->family == AF_INET)
-		addr_equals = a->addr.s_addr == b->addr.s_addr;
+	if (a->family == b->family) {
+		if (a->family == AF_INET)
+			addr_equals = a->addr.s_addr == b->addr.s_addr;
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
-	else
-		addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
+		else
+			addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
+	} else if (a->family == AF_INET) {
+		if (ipv6_addr_v4mapped(&b->addr6))
+			addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3];
+	} else if (b->family == AF_INET) {
+		if (ipv6_addr_v4mapped(&a->addr6))
+			addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr;
 #endif
+	}
 
 	if (!addr_equals)
 		return false;
@@ -137,6 +142,7 @@ select_local_address(const struct pm_nl_pernet *pernet,
 		     struct mptcp_sock *msk)
 {
 	struct mptcp_pm_addr_entry *entry, *ret = NULL;
+	struct sock *sk = (struct sock *)msk;
 
 	rcu_read_lock();
 	__mptcp_flush_join_list(msk);
@@ -144,11 +150,20 @@ select_local_address(const struct pm_nl_pernet *pernet,
 		if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 			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;
+		}
+
 		/* avoid any address already in use by subflows and
 		 * pending join
 		 */
-		if (entry->addr.family == ((struct sock *)msk)->sk_family &&
-		    !lookup_subflow_by_saddr(&msk->conn_list, &entry->addr)) {
+		if (!lookup_subflow_by_saddr(&msk->conn_list, &entry->addr)) {
 			ret = entry;
 			break;
 		}
@@ -310,7 +325,6 @@ void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 
 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
-	struct mptcp_addr_info remote = { 0 };
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *local;
 	struct pm_nl_pernet *pernet;
@@ -344,13 +358,14 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	/* check if should create a new subflow */
 	if (msk->pm.local_addr_used < msk->pm.local_addr_max &&
 	    msk->pm.subflows < msk->pm.subflows_max) {
-		remote_address((struct sock_common *)sk, &remote);
-
 		local = select_local_address(pernet, msk);
 		if (local) {
+			struct mptcp_addr_info remote = { 0 };
+
 			msk->pm.local_addr_used++;
 			msk->pm.subflows++;
 			check_work_pending(msk);
+			remote_address((struct sock_common *)sk, &remote);
 			spin_unlock_bh(&msk->pm.lock);
 			__mptcp_subflow_connect(sk, &local->addr, &remote);
 			spin_lock_bh(&msk->pm.lock);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 721059916c968..586156281e5a0 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1085,21 +1085,31 @@ void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
 #endif
 
 static void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
-				struct sockaddr_storage *addr)
+				struct sockaddr_storage *addr,
+				unsigned short family)
 {
 	memset(addr, 0, sizeof(*addr));
-	addr->ss_family = info->family;
+	addr->ss_family = family;
 	if (addr->ss_family == AF_INET) {
 		struct sockaddr_in *in_addr = (struct sockaddr_in *)addr;
 
-		in_addr->sin_addr = info->addr;
+		if (info->family == AF_INET)
+			in_addr->sin_addr = info->addr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+		else if (ipv6_addr_v4mapped(&info->addr6))
+			in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3];
+#endif
 		in_addr->sin_port = info->port;
 	}
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 	else if (addr->ss_family == AF_INET6) {
 		struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr;
 
-		in6_addr->sin6_addr = info->addr6;
+		if (info->family == AF_INET)
+			ipv6_addr_set_v4mapped(info->addr.s_addr,
+					       &in6_addr->sin6_addr);
+		else
+			in6_addr->sin6_addr = info->addr6;
 		in6_addr->sin6_port = info->port;
 	}
 #endif
@@ -1143,11 +1153,11 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	subflow->remote_key = msk->remote_key;
 	subflow->local_key = msk->local_key;
 	subflow->token = msk->token;
-	mptcp_info2sockaddr(loc, &addr);
+	mptcp_info2sockaddr(loc, &addr, ssk->sk_family);
 
 	addrlen = sizeof(struct sockaddr_in);
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
-	if (loc->family == AF_INET6)
+	if (addr.ss_family == AF_INET6)
 		addrlen = sizeof(struct sockaddr_in6);
 #endif
 	ssk->sk_bound_dev_if = loc->ifindex;
@@ -1163,7 +1173,7 @@ 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 = !!(loc->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
-	mptcp_info2sockaddr(remote, &addr);
+	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
 
 	mptcp_add_pending_subflow(msk, subflow);
 	err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index f74cd993b168e..be34b9ccbd202 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -790,6 +790,81 @@ chk_join_nr "remove subflow and signal IPv6" 2 2 2
 chk_add_nr 1 1
 chk_rm_nr 1 1
 
+# subflow IPv4-mapped to IPv4-mapped
+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 "::ffff:10.0.3.2" flags subflow
+run_tests $ns1 $ns2 "::ffff:10.0.1.1"
+chk_join_nr "single subflow IPv4-mapped" 1 1 1
+
+# signal address IPv4-mapped with IPv4-mapped sk
+reset
+ip netns exec $ns1 ./pm_nl_ctl limits 0 1
+ip netns exec $ns2 ./pm_nl_ctl limits 1 1
+ip netns exec $ns1 ./pm_nl_ctl add "::ffff:10.0.2.1" flags signal
+run_tests $ns1 $ns2 "::ffff:10.0.1.1"
+chk_join_nr "signal address IPv4-mapped" 1 1 1
+chk_add_nr 1 1
+
+# subflow v4-map-v6
+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
+run_tests $ns1 $ns2 "::ffff:10.0.1.1"
+chk_join_nr "single subflow v4-map-v6" 1 1 1
+
+# signal address v4-map-v6
+reset
+ip netns exec $ns1 ./pm_nl_ctl limits 0 1
+ip netns exec $ns2 ./pm_nl_ctl limits 1 1
+ip netns exec $ns1 ./pm_nl_ctl add 10.0.2.1 flags signal
+run_tests $ns1 $ns2 "::ffff:10.0.1.1"
+chk_join_nr "signal address v4-map-v6" 1 1 1
+chk_add_nr 1 1
+
+# subflow v6-map-v4
+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 "::ffff:10.0.3.2" flags subflow
+run_tests $ns1 $ns2 10.0.1.1
+chk_join_nr "single subflow v6-map-v4" 1 1 1
+
+# signal address v6-map-v4
+reset
+ip netns exec $ns1 ./pm_nl_ctl limits 0 1
+ip netns exec $ns2 ./pm_nl_ctl limits 1 1
+ip netns exec $ns1 ./pm_nl_ctl add "::ffff:10.0.2.1" flags signal
+run_tests $ns1 $ns2 10.0.1.1
+chk_join_nr "signal address v6-map-v4" 1 1 1
+chk_add_nr 1 1
+
+# no subflow IPv6 to v4 address
+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 dead:beef:2::2 flags subflow
+run_tests $ns1 $ns2 10.0.1.1
+chk_join_nr "no JOIN with diff families v4-v6" 0 0 0
+
+# no subflow IPv6 to v4 address even if v6 has a valid v4 at the end
+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 dead:beef:2::10.0.3.2 flags subflow
+run_tests $ns1 $ns2 10.0.1.1
+chk_join_nr "no JOIN with diff families v4-v6-2" 0 0 0
+
+# no subflow IPv4 to v6 address, no need to slow down too then
+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
+run_tests $ns1 $ns2 dead:beef:1::1
+chk_join_nr "no JOIN with diff families v6-v4" 0 0 0
+
 # single subflow, backup
 reset
 ip netns exec $ns1 ./pm_nl_ctl limits 0 1
diff --git a/tools/testing/selftests/net/mptcp/settings b/tools/testing/selftests/net/mptcp/settings
index 026384c189c91..a62d2fa1275c6 100644
--- a/tools/testing/selftests/net/mptcp/settings
+++ b/tools/testing/selftests/net/mptcp/settings
@@ -1 +1 @@
-timeout=450
+timeout=600