Merge branch 'mptcp-expose-more-info-and-small-improvements'

Matthieu Baerts says:

====================
mptcp: expose more info and small improvements

Patch 1-3/9 track and expose some aggregated data counters at the MPTCP
level: the number of retransmissions and the bytes that have been
transferred. The first patch prepares the work by moving where snd_una
is updated for fallback sockets while the last patch adds some tests to
cover the new code.

Patch 4-6/9 introduce a new getsockopt for SOL_MPTCP: MPTCP_FULL_INFO.
This new socket option allows to combine info from MPTCP_INFO,
MPTCP_TCPINFO and MPTCP_SUBFLOW_ADDRS socket options into one. It can be
needed to have all info in one because the path-manager can close and
re-create subflows between getsockopt() and fooling the accounting. The
first patch introduces a unique subflow ID to easily detect when
subflows are being re-created with the same 5-tuple while the last patch
adds some tests to cover the new code.

Please note that patch 5/9 ("mptcp: introduce MPTCP_FULL_INFO getsockopt")
can reveal a bug that were there for a bit of time, see [1]. A fix has
recently been fixed to netdev for the -net tree: "mptcp: ensure listener
is unhashed before updating the sk status", see [2]. There is no
conflicts between the two patches but it might be better to apply this
series after the one for -net and after having merged "net" into
"net-next".

Patch 7/9 is similar to commit 47867f0a7e83 ("selftests: mptcp: join:
skip check if MIB counter not supported") recently applied in the -net
tree but here it adapts the new code that is only in net-next (and it
fixes a merge conflict resolution which didn't have any impact).

Patch 8 and 9/9 are two simple refactoring. One to consolidate the
transition to TCP_CLOSE in mptcp_do_fastclose() and avoid duplicated
code. The other one reduces the scope of an argument passed to
mptcp_pm_alloc_anno_list() function.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/407 [1]
Link: https://lore.kernel.org/netdev/20230620-upstream-net-20230620-misc-fixes-for-v6-4-v1-0-f36aa5eae8b9@tessares.net/ [2]
====================

Link: https://lore.kernel.org/r/20230620-upstream-net-next-20230620-mptcp-expose-more-info-and-misc-v1-0-62b9444bfd48@tessares.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 32af2d278cb4..ee9c49f949a2 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -123,6 +123,11 @@ struct mptcp_info {
 	__u8	mptcpi_local_addr_used;
 	__u8	mptcpi_local_addr_max;
 	__u8	mptcpi_csum_enabled;
+	__u32	mptcpi_retransmits;
+	__u64	mptcpi_bytes_retrans;
+	__u64	mptcpi_bytes_sent;
+	__u64	mptcpi_bytes_received;
+	__u64	mptcpi_bytes_acked;
 };
 
 /*
@@ -244,9 +249,33 @@ struct mptcp_subflow_addrs {
 	};
 };
 
+struct mptcp_subflow_info {
+	__u32				id;
+	struct mptcp_subflow_addrs	addrs;
+};
+
+struct mptcp_full_info {
+	__u32		size_tcpinfo_kernel;	/* must be 0, set by kernel */
+	__u32		size_tcpinfo_user;
+	__u32		size_sfinfo_kernel;	/* must be 0, set by kernel */
+	__u32		size_sfinfo_user;
+	__u32		num_subflows;		/* must be 0, set by kernel (real subflow count) */
+	__u32		size_arrays_user;	/* max subflows that userspace is interested in;
+						 * the buffers at subflow_info/tcp_info
+						 * are respectively at least:
+						 *  size_arrays * size_sfinfo_user
+						 *  size_arrays * size_tcpinfo_user
+						 * bytes wide
+						 */
+	__aligned_u64		subflow_info;
+	__aligned_u64		tcp_info;
+	struct mptcp_info	mptcp_info;
+};
+
 /* MPTCP socket options */
 #define MPTCP_INFO		1
 #define MPTCP_TCPINFO		2
 #define MPTCP_SUBFLOW_ADDRS	3
+#define MPTCP_FULL_INFO		4
 
 #endif /* _UAPI_MPTCP_H */