Merge branch 'mptcp-next'

Mat Martineau says:

====================
mptcp: Add SOL_MPTCP getsockopt support

Here's the first new MPTCP feature for the v5.16 cycle, and I'll defer
to Florian's helpful description of the series implementing some new
MPTCP socket options:

========

This adds the MPTCP_INFO, MPTCP_TCPINFO and MPTCP_SUBFLOW_ADDRS
mptcp getsockopt optnames.

MPTCP_INFO exposes the mptcp_info struct as an alternative to the
existing netlink diag interface.

MPTCP_TCPINFO exposes the tcp_info struct.
Unlike SOL_TCP/TCP_INFO, this returns one struct for each active
subflow.

MPTCP_SUBFLOW_ADDRS allows userspace to discover the ip addresses/ports
used by the local and remote endpoints, one for each active tcp subflow.

MPTCP_TCPINFO and MPTCP_SUBFLOW_ADDRS share the same meta-header that
needs to be pre-filled by userspace with the size of the data structures
it expects.  This is done to allow extension of the involved structs
later on, without breaking backwards compatibility.

The meta-structure can also be used to discover the required space
to obtain all information, as kernel will fill in the number of
active subflows even if there is not enough room for the requested info
itself.

More information is available in the individual patches.
Last patch adds test cases for the three optnames.

========
====================

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

3 files changed, 40 insertions, 0 deletions

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 041d6032a348..7612d760b6a9 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -364,6 +364,7 @@ struct ucred {
 #define SOL_KCM		281
 #define SOL_TLS		282
 #define SOL_XDP		283
+#define SOL_MPTCP	284
 
 /* IPX options */
 #define IPX_TYPE	1
diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 6026bbefbffd..f83fa48408b3 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -12,6 +12,8 @@
 #include <linux/tcp.h>
 #include <linux/types.h>
 
+struct mptcp_info;
+struct mptcp_sock;
 struct seq_file;
 
 /* MPTCP sk_buff extension data */
@@ -121,6 +123,8 @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 			 struct mptcp_out_options *opts);
 
+void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
+
 /* move the skb extension owership, with the assumption that 'to' is
  * newly allocated
  */
diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index f66038b9551f..c8cc46f80a16 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -4,6 +4,13 @@
 
 #include <linux/const.h>
 #include <linux/types.h>
+#include <linux/in.h>		/* for sockaddr_in			*/
+#include <linux/in6.h>		/* for sockaddr_in6			*/
+#include <linux/socket.h>	/* for sockaddr_storage and sa_family	*/
+
+#ifndef __KERNEL__
+#include <sys/socket.h>		/* for struct sockaddr			*/
+#endif
 
 #define MPTCP_SUBFLOW_FLAG_MCAP_REM		_BITUL(0)
 #define MPTCP_SUBFLOW_FLAG_MCAP_LOC		_BITUL(1)
@@ -193,4 +200,32 @@ enum mptcp_event_attr {
 #define MPTCP_RST_EBADPERF	5
 #define MPTCP_RST_EMIDDLEBOX	6
 
+struct mptcp_subflow_data {
+	__u32		size_subflow_data;		/* size of this structure in userspace */
+	__u32		num_subflows;			/* must be 0, set by kernel */
+	__u32		size_kernel;			/* must be 0, set by kernel */
+	__u32		size_user;			/* size of one element in data[] */
+} __attribute__((aligned(8)));
+
+struct mptcp_subflow_addrs {
+	union {
+		__kernel_sa_family_t sa_family;
+		struct sockaddr sa_local;
+		struct sockaddr_in sin_local;
+		struct sockaddr_in6 sin6_local;
+		struct __kernel_sockaddr_storage ss_local;
+	};
+	union {
+		struct sockaddr sa_remote;
+		struct sockaddr_in sin_remote;
+		struct sockaddr_in6 sin6_remote;
+		struct __kernel_sockaddr_storage ss_remote;
+	};
+};
+
+/* MPTCP socket options */
+#define MPTCP_INFO		1
+#define MPTCP_TCPINFO		2
+#define MPTCP_SUBFLOW_ADDRS	3
+
 #endif /* _UAPI_MPTCP_H */