Merge branch 'mptcp-fixes'

Mat Martineau says:

====================
mptcp: A few fixes

This set has three separate changes for the net-next tree:

Patch 1 guarantees safe handling and a warning if a NULL value is
encountered when gathering subflow data for the MPTCP_SUBFLOW_ADDRS
socket option.

Patch 2 increases the default number of subflows allowed per MPTCP
connection.

Patch 3 makes an existing function 'static'.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 16 insertions, 10 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 050eea231528..7b96be1e9f14 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -654,9 +654,9 @@ void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
 	}
 }
 
-int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
-				 struct mptcp_addr_info *addr,
-				 u8 bkup)
+static int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
+					struct mptcp_addr_info *addr,
+					u8 bkup)
 {
 	struct mptcp_subflow_context *subflow;
 
@@ -2052,6 +2052,9 @@ static int __net_init pm_nl_init_net(struct net *net)
 	struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
 
 	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
+
+	/* Cit. 2 subflows ought to be enough for anybody. */
+	pernet->subflows_max = 2;
 	pernet->next_id = 1;
 	pernet->stale_loss_cnt = 4;
 	spin_lock_init(&pernet->lock);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 7379ab580a7e..284fdcec067e 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -736,9 +736,6 @@ void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
 			       const struct mptcp_rm_list *rm_list);
 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
-int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
-				 struct mptcp_addr_info *addr,
-				 u8 bkup);
 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 8137cc3a4296..0f1e661c2032 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -861,6 +861,9 @@ static void mptcp_get_sub_addrs(const struct sock *sk, struct mptcp_subflow_addr
 	} else if (sk->sk_family == AF_INET6) {
 		const struct ipv6_pinfo *np = inet6_sk(sk);
 
+		if (WARN_ON_ONCE(!np))
+			return;
+
 		a->sin6_local.sin6_family = AF_INET6;
 		a->sin6_local.sin6_port = inet->inet_sport;
 
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 255793c5ac4f..293d349e21fe 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -945,12 +945,15 @@ subflows_tests()
 
 	# subflow limited by client
 	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 0
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 0
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
 	run_tests $ns1 $ns2 10.0.1.1
 	chk_join_nr "single subflow, limited by client" 0 0 0
 
 	# subflow limited by server
 	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 0
 	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 10.0.1.1
@@ -973,7 +976,7 @@ subflows_tests()
 	run_tests $ns1 $ns2 10.0.1.1
 	chk_join_nr "multiple subflows" 2 2 2
 
-	# multiple subflows limited by serverf
+	# multiple subflows limited by server
 	reset
 	ip netns exec $ns1 ./pm_nl_ctl limits 0 1
 	ip netns exec $ns2 ./pm_nl_ctl limits 0 2
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index 3c741abe034e..cbacf9f6538b 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -70,7 +70,7 @@ check()
 
 check "ip netns exec $ns1 ./pm_nl_ctl dump" "" "defaults addr list"
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 0
-subflows 0" "defaults limits"
+subflows 2" "defaults limits"
 
 ip netns exec $ns1 ./pm_nl_ctl add 10.0.1.1
 ip netns exec $ns1 ./pm_nl_ctl add 10.0.1.2 flags subflow dev lo
@@ -118,11 +118,11 @@ check "ip netns exec $ns1 ./pm_nl_ctl dump" "" "flush addrs"
 
 ip netns exec $ns1 ./pm_nl_ctl limits 9 1
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 0
-subflows 0" "rcv addrs above hard limit"
+subflows 2" "rcv addrs above hard limit"
 
 ip netns exec $ns1 ./pm_nl_ctl limits 1 9
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 0
-subflows 0" "subflows above hard limit"
+subflows 2" "subflows above hard limit"
 
 ip netns exec $ns1 ./pm_nl_ctl limits 8 8
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 8