[PATCH 5.11 047/152] mptcp: provide subflow aware release function

Greg Kroah-Hartman
2021-04-05T09:16:55Z

From: Florian Westphal <fw@strlen.de>

[ Upstream commit ad98dd37051e14fa8c785609430d907fcfd518ba ]

mptcp re-used inet(6)_release, so the subflow sockets are ignored.
Need to invoke ip(v6)_mc_drop_socket function to ensure mcast join
resources get free'd.

Fixes: 717e79c867ca5 ("mptcp: Add setsockopt()/getsockopt() socket operations")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/110
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mptcp/protocol.c | 55 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 53 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 88f2d900a347..c3299a4568a0 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -11,6 +11,7 @@
#include <linux/netdevice.h>
#include <linux/sched/signal.h>
#include <linux/atomic.h>
+#include <linux/igmp.h>
#include <net/sock.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
@@ -19,6 +20,7 @@
#include <net/tcp_states.h>
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
#include <net/transp_v6.h>
+#include <net/addrconf.h>
#endif
#include <net/mptcp.h>
#include <net/xfrm.h>
@@ -3368,10 +3370,34 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock,
return mask;
}

+static int mptcp_release(struct socket *sock)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = sock->sk;
+ struct mptcp_sock *msk;
+
+ if (!sk)
+ return 0;
+
+ lock_sock(sk);
+
+ msk = mptcp_sk(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ ip_mc_drop_socket(ssk);
+ }
+
+ release_sock(sk);
+
+ return inet_release(sock);
+}
+
static const struct proto_ops mptcp_stream_ops = {
.family = PF_INET,
.owner = THIS_MODULE,
- .release = inet_release,
+ .release = mptcp_release,
.bind = mptcp_bind,
.connect = mptcp_stream_connect,
.socketpair = sock_no_socketpair,
@@ -3418,10 +3444,35 @@ void __init mptcp_proto_init(void)
}

#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static int mptcp6_release(struct socket *sock)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk;
+ struct sock *sk = sock->sk;
+
+ if (!sk)
+ return 0;
+
+ lock_sock(sk);
+
+ msk = mptcp_sk(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ ip_mc_drop_socket(ssk);
+ ipv6_sock_mc_close(ssk);
+ ipv6_sock_ac_close(ssk);
+ }
+
+ release_sock(sk);
+ return inet6_release(sock);
+}
+
static const struct proto_ops mptcp_v6_stream_ops = {
.family = PF_INET6,
.owner = THIS_MODULE,
- .release = inet6_release,
+ .release = mptcp6_release,
.bind = mptcp_bind,
.connect = mptcp_stream_connect,
.socketpair = sock_no_socketpair,
--
2.30.1