[PATCH RFC net-next v4 01/12] vsock: a per-net vsock NS mode state

[Bobby Eshleman <bobbyeshleman@gmail.com>]

From: Bobby Eshleman <bobbyeshleman@meta.com>

Add the per-net vsock NS mode state. This only adds the structure for
holding the mode necessary and some of the definitions, but does not
integrate the functionality yet.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
 MAINTAINERS                 |  1 +
 include/net/af_vsock.h      | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/net/net_namespace.h |  4 ++++
 include/net/netns/vsock.h   | 18 ++++++++++++++++++
 4 files changed, 65 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 1bc1698bc5ae..76905fc1c1d3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26208,6 +26208,7 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/vhost/vsock.c
 F:	include/linux/virtio_vsock.h
+F:	include/net/netns/vsock.h
 F:	include/uapi/linux/virtio_vsock.h
 F:	net/vmw_vsock/virtio_transport.c
 F:	net/vmw_vsock/virtio_transport_common.c
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index d40e978126e3..d34bf7dbc69a 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -10,6 +10,7 @@
 
 #include <linux/kernel.h>
 #include <linux/workqueue.h>
+#include <net/netns/vsock.h>
 #include <net/sock.h>
 #include <uapi/linux/vm_sockets.h>
 
@@ -256,4 +257,45 @@ static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)
 {
 	return t->msgzerocopy_allow && t->msgzerocopy_allow();
 }
+
+static inline u8 vsock_net_mode(struct net *net)
+{
+	u8 ret;
+
+	spin_lock_bh(&net->vsock.lock);
+	ret = net->vsock.ns_mode;
+	spin_unlock_bh(&net->vsock.lock);
+	return ret;
+}
+
+static inline void vsock_net_set_mode(struct net *net, u8 mode)
+{
+	spin_lock_bh(&net->vsock.lock);
+	net->vsock.ns_mode = mode;
+	net->vsock.written = true;
+	spin_unlock_bh(&net->vsock.lock);
+}
+
+/* Return true if mode has already been written once. Otherwise, return false. */
+static inline bool vsock_net_mode_can_set(struct net *net)
+{
+	bool ret;
+
+	spin_lock_bh(&net->vsock.lock);
+	ret = !net->vsock.written;
+	spin_unlock_bh(&net->vsock.lock);
+
+	return ret;
+}
+
+/* Return true if vsock net mode check passes. Otherwise, return false.
+ *
+ * Read more about modes in comment header of net/vmw_vsock/af_vsock.c.
+ */
+static inline bool vsock_net_check_mode(struct net *n1, struct net *n2)
+{
+	return net_eq(n1, n2) ||
+	       (vsock_net_mode(n1) == VSOCK_NET_MODE_GLOBAL &&
+		vsock_net_mode(n2) == VSOCK_NET_MODE_GLOBAL);
+}
 #endif /* __AF_VSOCK_H__ */
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 025a7574b275..005c0da4fb62 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -37,6 +37,7 @@
 #include <net/netns/smc.h>
 #include <net/netns/bpf.h>
 #include <net/netns/mctp.h>
+#include <net/netns/vsock.h>
 #include <net/net_trackers.h>
 #include <linux/ns_common.h>
 #include <linux/idr.h>
@@ -196,6 +197,9 @@ struct net {
 	/* Move to a better place when the config guard is removed. */
 	struct mutex		rtnl_mutex;
 #endif
+#if IS_ENABLED(CONFIG_VSOCKETS)
+	struct netns_vsock	vsock;
+#endif
 } __randomize_layout;
 
 #include <linux/seq_file_net.h>
diff --git a/include/net/netns/vsock.h b/include/net/netns/vsock.h
new file mode 100644
index 000000000000..0bad4652815c
--- /dev/null
+++ b/include/net/netns/vsock.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __NET_NET_NAMESPACE_VSOCK_H
+#define __NET_NET_NAMESPACE_VSOCK_H
+
+#include <linux/types.h>
+
+#define VSOCK_NET_MODE_GLOBAL	1
+#define VSOCK_NET_MODE_LOCAL	(1 << 1)
+
+struct netns_vsock {
+	struct ctl_table_header *vsock_hdr;
+	spinlock_t lock;
+
+	/* protected by lock */
+	u8 ns_mode;
+	bool written;
+};
+#endif /* __NET_NET_NAMESPACE_VSOCK_H */

-- 
2.47.3