netlink: Diag core and basic socket info dumping (v2)

The netlink_diag can be built as a module, just like it's done in
unix sockets.

The core dumping message carries the basic info about netlink sockets:
family, type and protocol, portis, dst_group, dst_portid, state.

Groups can be received as an optional parameter NETLINK_DIAG_GROUPS.

Netlink sockets cab be filtered by protocols.

The socket inode number and cookie is reserved for future per-socket info
retrieving. The per-protocol filtering is also reserved for future by
requiring the sdiag_protocol to be zero.

The file /proc/net/netlink doesn't provide enough information for
dumping netlink sockets. It doesn't provide dst_group, dst_portid,
groups above 32.

v2: fix NETLINK_DIAG_MAX. Now it's equal to the last constant.

Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 0 deletions

diff --git a/include/uapi/linux/netlink_diag.h b/include/uapi/linux/netlink_diag.h
new file mode 100644
index 000000000000..88009a31cd06
--- /dev/null
+++ b/include/uapi/linux/netlink_diag.h
@@ -0,0 +1,42 @@
+#ifndef __NETLINK_DIAG_H__
+#define __NETLINK_DIAG_H__
+
+#include <linux/types.h>
+
+struct netlink_diag_req {
+	__u8	sdiag_family;
+	__u8	sdiag_protocol;
+	__u16	pad;
+	__u32	ndiag_ino;
+	__u32	ndiag_show;
+	__u32	ndiag_cookie[2];
+};
+
+struct netlink_diag_msg {
+	__u8	ndiag_family;
+	__u8	ndiag_type;
+	__u8	ndiag_protocol;
+	__u8	ndiag_state;
+
+	__u32	ndiag_portid;
+	__u32	ndiag_dst_portid;
+	__u32	ndiag_dst_group;
+	__u32	ndiag_ino;
+	__u32	ndiag_cookie[2];
+};
+
+enum {
+	NETLINK_DIAG_MEMINFO,
+	NETLINK_DIAG_GROUPS,
+
+	__NETLINK_DIAG_MAX,
+};
+
+#define NETLINK_DIAG_MAX (__NETLINK_DIAG_MAX - 1)
+
+#define NDIAG_PROTO_ALL		((__u8) ~0)
+
+#define NDIAG_SHOW_MEMINFO	0x00000001 /* show memory info of a socket */
+#define NDIAG_SHOW_GROUPS	0x00000002 /* show groups of a netlink socket */
+
+#endif