Series comparison

This is a follow up to the topic discussed in recent pubblic mtg.

Introduces unique id for accurate subflow stats tracking and
aggregate mptcp counters, plus some minimal self-tests.

The tests themself do not take in account support for running on
older kernel.

This is on top of "mptcp: a bunch of data race fixes".

There should be non trivial conflicts with:

"mptcp: use get_retrans wrapper".

v3 -> v4:
 - change binary layout for MPTCP_FULL_INFO structs (Florian)

v2 -> v3:
 - address Matttbe comments on patch 1, 2 and 5, see the indivdual
   patches changelog for the details

v1 -> v2:
 - introduce MPTCP_FULL_INFO instead of overloading a tcp_info field
 - add related self-tests
 - fix a couple of subflow_id initialization bugs

Paolo Abeni (6):
  mptcp: add subflow unique id
  mptcp: introduce MPTCP_FULL_INFO getsockopt
  mptcp: move snd_una update earlier for fallback socket.
  mptcp: track some aggregate data counters.
  selftests: mptcp: explicitly tests aggregate counters
  selftests: mptcp: add MPTCP_FULL_INFO testcase

-- 
2.40.1

The user-space need to preperly account the data received/sent by
individual subflows. When additional subflows are created and/or
closed during the MPTCP socket lifetime, the information currently
exposed via MPTCP_TCPINFO are not enough: subflows are identifed only
by the sequential position inside the info dumps, and that will change
with the above mentioned events.

To solve the above problem, this patch introduces a new subflow identifier
that is unique inside the given mptcp socket scope.

The initial subflow get the id 1 and the other subflows get incremental
values at join time.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
v2 -> v3:
 - fix msk subflow_id init (Matttbe)

v1 -> v2:
 - properly set subflow_id for the first passive subflow and active subflows, too
 - drop the tcpi_fackets overload
---
 net/mptcp/protocol.c | 6 ++++++
 net/mptcp/protocol.h | 5 ++++-
 net/mptcp/subflow.c  | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -XXX,XX +XXX,XX @@ static int __mptcp_socket_create(struct mptcp_sock *msk)
 	list_add(&subflow->node, &msk->conn_list);
 	sock_hold(ssock->sk);
 	subflow->request_mptcp = 1;
+	subflow->subflow_id = msk->subflow_id++;
 
 	/* This is the first subflow, always with id 0 */
 	subflow->local_id_valid = 1;
@@ -XXX,XX +XXX,XX @@ static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
 	if (sk->sk_socket && !ssk->sk_socket)
 		mptcp_sock_graft(ssk, sk->sk_socket);
 
+	mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;
 	mptcp_sockopt_sync_locked(msk, ssk);
 	mptcp_subflow_joined(msk, ssk);
 	return true;
@@ -XXX,XX +XXX,XX @@ static int __mptcp_init_sock(struct sock *sk)
 	WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
 	WRITE_ONCE(msk->allow_infinite_fallback, true);
 	msk->recovery = false;
+	msk->subflow_id = 1;
 
 	mptcp_pm_data_init(msk);
 
@@ -XXX,XX +XXX,XX @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 	msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
 	mptcp_init_sched(msk, mptcp_sk(sk)->sched);
 
+	/* passive msk is created after the first/MPC subflow */
+	msk->subflow_id = 2;
+
 	sock_reset_flag(nsk, SOCK_RCU_FREE);
 	security_inet_csk_clone(nsk, req);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_sock {
 		u64	rtt_us; /* last maximum rtt of subflows */
 	} rcvq_space;
 
-	u32 setsockopt_seq;
+	u32		subflow_id;
+	u32		setsockopt_seq;
 	char		ca_name[TCP_CA_NAME_MAX];
 	struct mptcp_sock	*dl_next;
 };
@@ -XXX,XX +XXX,XX @@ struct mptcp_subflow_context {
 	u8	reset_reason:4;
 	u8	stale_count;
 
+	u32	subflow_id;
+
 	long	delegated_status;
 	unsigned long	fail_tout;
 
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -XXX,XX +XXX,XX @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 			if (!ctx->conn)
 				goto fallback;
 
+			ctx->subflow_id = 1;
 			owner = mptcp_sk(ctx->conn);
 			mptcp_pm_new_connection(owner, child, 1);
 
@@ -XXX,XX +XXX,XX @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	subflow->remote_id = remote_id;
 	subflow->request_join = 1;
 	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	subflow->subflow_id = msk->subflow_id++;
 	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
 
 	sock_hold(ssk);
-- 
2.40.1

Some user-space applications want to monitor the subflows utilization.

Dumping the per subflow tcp_info is not enough, as the PM could close
and re-create the subflows under-the-hood, fooling the accounting.
Even checking the src/dst addresses used by each subflow could not
be enough, because new subflows could re-use the same address/port of
the just closed one.

This patch introduces a new socket option, allow dumping all the relevant
information all-at-once (everything, everywhere...), in a consistent manner.

To reuse the existing helper to manipulate the new struct, keep the binary
layout of the initial few fields the same as mptcp_subflow_data.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
v3 -> v4:
 - full_info struct re-design (Florian)

v2 -> v3:
 - added missing changelog (oops)
---
 include/uapi/linux/mptcp.h |  25 ++++++
 net/mptcp/sockopt.c        | 165 +++++++++++++++++++++++++++++++++----
 2 files changed, 174 insertions(+), 16 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index XXXXXXX..XXXXXXX 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -XXX,XX +XXX,XX @@
 #include <linux/in.h>		/* for sockaddr_in			*/
 #include <linux/in6.h>		/* for sockaddr_in6			*/
 #include <linux/socket.h>	/* for sockaddr_storage and sa_family	*/
+#include <linux/tcp.h>		/* for tcp_info				*/
 
 #define MPTCP_SUBFLOW_FLAG_MCAP_REM		_BITUL(0)
 #define MPTCP_SUBFLOW_FLAG_MCAP_LOC		_BITUL(1)
@@ -XXX,XX +XXX,XX @@ struct mptcp_subflow_addrs {
 	};
 };
 
+struct mptcp_subflow_info {
+	__u32				id;
+	struct mptcp_subflow_addrs	addrs;
+};
+
+struct mptcp_subflow_full_info {
+	__u32		size_subflow_full_info;	/* size of this structure in userspace */
+	__u32		num_subflows_kern;	/* must be 0, set by kernel (real subflow count) */
+	__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_user;	/* max subflows that userspace is interested in;
+						 * the buffers at subflow_info_addr/tcp_info_addr
+						 * are respectively at least:
+						 *  num_subflows_user * size_sfinfo_user
+						 *  num_subflows_user * size_tcpinfo_user
+						 * bytes wide
+						 */
+	__aligned_u64	subflow_info_addr;
+	__aligned_u64	tcp_info_addr;
+} __attribute__((aligned(8)));
+
 /* 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 */
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -XXX,XX +XXX,XX @@
 #include <net/mptcp.h>
 #include "protocol.h"
 
-#define MIN_INFO_OPTLEN_SIZE	16
+#define MIN_INFO_OPTLEN_SIZE		16
+#define MIN_FULL_INFO_OPTLEN_SIZE	48
 
 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
 {
@@ -XXX,XX +XXX,XX @@ static int mptcp_getsockopt_info(struct mptcp_sock *msk, char __user *optval, in
 	return 0;
 }
 
-static int mptcp_put_subflow_data(struct mptcp_subflow_data *sfd,
-				  char __user *optval,
-				  u32 copied,
-				  int __user *optlen)
+static int __mptcp_put_subflow_data(struct mptcp_subflow_data *sfd,
+				    int size_subflow_data_kern,
+				    char __user *optval,
+				    u32 copied,
+				    int __user *optlen)
 {
-	u32 copylen = min_t(u32, sfd->size_subflow_data, sizeof(*sfd));
+	u32 copylen = min_t(u32, sfd->size_subflow_data, size_subflow_data_kern);
 
 	if (copied)
 		copied += sfd->size_subflow_data;
@@ -XXX,XX +XXX,XX @@ static int mptcp_put_subflow_data(struct mptcp_subflow_data *sfd,
 	return 0;
 }
 
-static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
-				  char __user *optval, int __user *optlen)
+static int mptcp_put_subflow_data(struct mptcp_subflow_data *sfd,
+				  char __user *optval,
+				  u32 copied,
+				  int __user *optlen)
+{
+	return __mptcp_put_subflow_data(sfd, sizeof(*sfd), optval, copied, optlen);
+}
+
+static int __mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
+				    int min_info_optlen_size,
+				    char __user *optval,
+				    int __user *optlen)
 {
 	int len, copylen;
 
 	if (get_user(len, optlen))
 		return -EFAULT;
 
-	/* if mptcp_subflow_data size is changed, need to adjust
-	 * this function to deal with programs using old version.
-	 */
-	BUILD_BUG_ON(sizeof(*sfd) != MIN_INFO_OPTLEN_SIZE);
-
-	if (len < MIN_INFO_OPTLEN_SIZE)
+	if (len < min_info_optlen_size)
 		return -EINVAL;
 
 	memset(sfd, 0, sizeof(*sfd));
 
-	copylen = min_t(unsigned int, len, sizeof(*sfd));
+	copylen = min_t(unsigned int, len, min_info_optlen_size);
 	if (copy_from_user(sfd, optval, copylen))
 		return -EFAULT;
 
@@ -XXX,XX +XXX,XX @@ static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
 	    sfd->size_user > INT_MAX)
 		return -EINVAL;
 
-	if (sfd->size_subflow_data < MIN_INFO_OPTLEN_SIZE ||
+	if (sfd->size_subflow_data < min_info_optlen_size ||
 	    sfd->size_subflow_data > len)
 		return -EINVAL;
 
@@ -XXX,XX +XXX,XX @@ static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
 	return len - sfd->size_subflow_data;
 }
 
+static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
+				  char __user *optval,
+				  int __user *optlen)
+{
+	/* if mptcp_subflow_data size is changed, need to adjust
+	 * this function to deal with programs using old version.
+	 */
+	BUILD_BUG_ON(sizeof(*sfd) != MIN_INFO_OPTLEN_SIZE);
+
+	return __mptcp_get_subflow_data(sfd, MIN_INFO_OPTLEN_SIZE,
+					optval, optlen);
+}
+
 static int mptcp_getsockopt_tcpinfo(struct mptcp_sock *msk, char __user *optval,
 				    int __user *optlen)
 {
@@ -XXX,XX +XXX,XX @@ static int mptcp_getsockopt_subflow_addrs(struct mptcp_sock *msk, char __user *o
 	return 0;
 }
 
+static int mptcp_get_full_subflow_info(struct mptcp_subflow_full_info *sffi,
+				       char __user *optval,
+				       int __user *optlen)
+{
+	struct mptcp_subflow_data *sfd = (struct mptcp_subflow_data *)sffi;
+	int len;
+
+	BUILD_BUG_ON(sizeof(*sffi) != MIN_FULL_INFO_OPTLEN_SIZE);
+
+	len = __mptcp_get_subflow_data(sfd, MIN_FULL_INFO_OPTLEN_SIZE,
+				       optval, optlen);
+	if (len < 0)
+		return len;
+
+	if (sffi->size_tcpinfo_kernel)
+		return -EINVAL;
+
+	if (sffi->size_sfinfo_user > INT_MAX)
+		return -EINVAL;
+
+	return len;
+}
+
+static int mptcp_put_subflow_full_info(struct mptcp_subflow_full_info *sffi,
+				       char __user *optval,
+				       u32 copied,
+				       int __user *optlen)
+{
+	struct mptcp_subflow_data *sfd = (struct mptcp_subflow_data *)sffi;
+
+	return __mptcp_put_subflow_data(sfd, sizeof(*sffi), optval, copied, optlen);
+}
+
+static int mptcp_getsockopt_full_info(struct mptcp_sock *msk, char __user *optval,
+				      int __user *optlen)
+{
+	struct mptcp_subflow_context *subflow;
+	struct sock *sk = (struct sock *)msk;
+	unsigned int sfcount = 0, copied = 0;
+	struct mptcp_subflow_full_info sffi;
+	void __user *tcpinfoptr, *sfinfoptr;
+	int len;
+
+	len = mptcp_get_full_subflow_info(&sffi, optval, optlen);
+	if (len < 0)
+		return len;
+
+	/* don't bother filling the mptcp info if there is not enough
+	 * user-space-provided storage
+	 */
+	if (len > 0) {
+		struct mptcp_info mptcp_info;
+		char __user *infoptr;
+		int mptcp_info_len;
+
+		infoptr = optval + sffi.size_subflow_full_info;
+		memset(&mptcp_info, 0, sizeof(mptcp_info));
+		mptcp_info_len = min_t(unsigned int, len, sizeof(struct mptcp_info));
+
+		mptcp_diag_fill_info(msk, &mptcp_info);
+
+		if (copy_to_user(infoptr, &mptcp_info, mptcp_info_len))
+			return -EFAULT;
+
+		copied += mptcp_info_len;
+	}
+
+	sffi.size_tcpinfo_kernel = sizeof(struct tcp_info);
+	sffi.size_tcpinfo_user = min_t(unsigned int, sffi.size_tcpinfo_user,
+				       sizeof(struct tcp_info));
+	sfinfoptr = (void __force __user *)sffi.subflow_info_addr;
+	sffi.size_sfinfo_kernel = sizeof(struct mptcp_subflow_info);
+	sffi.size_sfinfo_user = min_t(unsigned int, sffi.size_sfinfo_user,
+				      sizeof(struct mptcp_subflow_info));
+	tcpinfoptr = (void __force __user *)sffi.tcp_info_addr;
+
+	lock_sock(sk);
+	mptcp_for_each_subflow(msk, subflow) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+		if (sfcount++ < sffi.num_subflows_user) {
+			struct mptcp_subflow_info sfinfo;
+			struct tcp_info tcp_info;
+
+			memset(&sfinfo, 0, sizeof(sfinfo));
+			sfinfo.id = subflow->subflow_id;
+			mptcp_get_sub_addrs(ssk, &sfinfo.addrs);
+			if (copy_to_user(sfinfoptr, &sfinfo, sffi.size_sfinfo_user))
+				goto fail_release;
+
+			tcp_get_info(ssk, &tcp_info);
+			if (copy_to_user(tcpinfoptr, &tcp_info, sffi.size_tcpinfo_user))
+				goto fail_release;
+
+			tcpinfoptr += sffi.size_tcpinfo_user;
+			sfinfoptr += sffi.size_sfinfo_user;
+		}
+	}
+	release_sock(sk);
+
+	sffi.num_subflows_kern = sfcount;
+	if (mptcp_put_subflow_full_info(&sffi, optval, copied, optlen))
+		return -EFAULT;
+
+	return 0;
+
+fail_release:
+	release_sock(sk);
+	return -EFAULT;
+}
+
 static int mptcp_put_int_option(struct mptcp_sock *msk, char __user *optval,
 				int __user *optlen, int val)
 {
@@ -XXX,XX +XXX,XX @@ static int mptcp_getsockopt_sol_mptcp(struct mptcp_sock *msk, int optname,
 	switch (optname) {
 	case MPTCP_INFO:
 		return mptcp_getsockopt_info(msk, optval, optlen);
+	case MPTCP_FULL_INFO:
+		return mptcp_getsockopt_full_info(msk, optval, optlen);
 	case MPTCP_TCPINFO:
 		return mptcp_getsockopt_tcpinfo(msk, optval, optlen);
 	case MPTCP_SUBFLOW_ADDRS:
-- 
2.40.1

That will avoid an unneeded conditional in both the fast-path
and in the fallback case and will simplify a bit the next
patch.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/options.c  | 6 ++++++
 net/mptcp/protocol.c | 6 ------
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -XXX,XX +XXX,XX @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 		mptcp_data_lock(subflow->conn);
 		if (sk_stream_memory_free(sk))
 			__mptcp_check_push(subflow->conn, sk);
+
+		/* on fallback we just need to ignore the msk-level snd_una, as
+		 * this is really plain TCP
+		 */
+		msk->snd_una = READ_ONCE(msk->snd_nxt);
+
 		__mptcp_data_acked(subflow->conn);
 		mptcp_data_unlock(subflow->conn);
 		return true;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -XXX,XX +XXX,XX @@ static void __mptcp_clean_una(struct sock *sk)
 	struct mptcp_data_frag *dtmp, *dfrag;
 	u64 snd_una;
 
-	/* on fallback we just need to ignore snd_una, as this is really
-	 * plain TCP
-	 */
-	if (__mptcp_check_fallback(msk))
-		msk->snd_una = READ_ONCE(msk->snd_nxt);
-
 	snd_una = msk->snd_una;
 	list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
 		if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
-- 
2.40.1

Currently there are no data transfer counters accounting for all
the subflows used by a given MPTCP socket. The user-space can compute
such figures aggregating the subflow info, but that is inaccurate
if any subflow is closed before the MPTCP socket itself.

Add the new counters in the MPTCP socket itself and expose them
via the existing diag and sockopt. While touching mptcp_diag_fill_info(),
acquire the relevant locks before fetching the msk data, to ensure
better data consistency

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 include/uapi/linux/mptcp.h |  5 +++++
 net/mptcp/options.c        | 10 ++++++++--
 net/mptcp/protocol.c       | 12 +++++++++++-
 net/mptcp/protocol.h       |  4 ++++
 net/mptcp/sockopt.c        | 22 +++++++++++++++++-----
 5 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index XXXXXXX..XXXXXXX 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -XXX,XX +XXX,XX @@ 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;
 };
 
 /*
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -XXX,XX +XXX,XX @@ u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq)
 	return cur_seq;
 }
 
+static void __mptcp_snd_una_update(struct mptcp_sock *msk, u64 new_snd_una)
+{
+	msk->bytes_acked += new_snd_una - msk->snd_una;
+	msk->snd_una = new_snd_una;
+}
+
 static void ack_update_msk(struct mptcp_sock *msk,
 			   struct sock *ssk,
 			   struct mptcp_options_received *mp_opt)
@@ -XXX,XX +XXX,XX @@ static void ack_update_msk(struct mptcp_sock *msk,
 		__mptcp_check_push(sk, ssk);
 
 	if (after64(new_snd_una, old_snd_una)) {
-		msk->snd_una = new_snd_una;
+		__mptcp_snd_una_update(msk, new_snd_una);
 		__mptcp_data_acked(sk);
 	}
 	mptcp_data_unlock(sk);
@@ -XXX,XX +XXX,XX @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 		/* on fallback we just need to ignore the msk-level snd_una, as
 		 * this is really plain TCP
 		 */
-		msk->snd_una = READ_ONCE(msk->snd_nxt);
+		__mptcp_snd_una_update(msk, READ_ONCE(msk->snd_nxt));
 
 		__mptcp_data_acked(subflow->conn);
 		mptcp_data_unlock(subflow->conn);
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -XXX,XX +XXX,XX @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
 
 	if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
 		/* in sequence */
+		msk->bytes_received += copy_len;
 		WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
 		tail = skb_peek_tail(&sk->sk_receive_queue);
 		if (tail && mptcp_try_coalesce(sk, tail, skb))
@@ -XXX,XX +XXX,XX @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
 			MPTCP_SKB_CB(skb)->map_seq += delta;
 			__skb_queue_tail(&sk->sk_receive_queue, skb);
 		}
+		msk->bytes_received += end_seq - msk->ack_seq;
 		msk->ack_seq = end_seq;
 		moved = true;
 	}
@@ -XXX,XX +XXX,XX @@ static void mptcp_update_post_push(struct mptcp_sock *msk,
 	 * that has been handed to the subflow for transmission
 	 * and skip update in case it was old dfrag.
 	 */
-	if (likely(after64(snd_nxt_new, msk->snd_nxt)))
+	if (likely(after64(snd_nxt_new, msk->snd_nxt))) {
+		msk->bytes_sent += snd_nxt_new - msk->snd_nxt;
 		msk->snd_nxt = snd_nxt_new;
+	}
 }
 
 void mptcp_check_and_set_pending(struct sock *sk)
@@ -XXX,XX +XXX,XX @@ static void __mptcp_retrans(struct sock *sk)
 			msk->last_snd = ssk;
 		}
 	}
+
+	msk->bytes_retrans += len;
 	dfrag->already_sent = max(dfrag->already_sent, len);
 
 reset_timer:
@@ -XXX,XX +XXX,XX @@ static int mptcp_disconnect(struct sock *sk, int flags)
 	WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
 	mptcp_pm_data_reset(msk);
 	mptcp_ca_reset(sk);
+	msk->bytes_acked = 0;
+	msk->bytes_received = 0;
+	msk->bytes_sent = 0;
+	msk->bytes_retrans = 0;
 
 	WRITE_ONCE(sk->sk_shutdown, 0);
 	sk_error_report(sk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_sock {
 	u64		local_key;
 	u64		remote_key;
 	u64		write_seq;
+	u64		bytes_sent;
 	u64		snd_nxt;
+	u64		bytes_received;
 	u64		ack_seq;
 	atomic64_t	rcv_wnd_sent;
 	u64		rcv_data_fin_seq;
+	u64		bytes_retrans;
 	int		rmem_fwd_alloc;
 	struct sock	*last_snd;
 	int		snd_burst;
@@ -XXX,XX +XXX,XX @@ struct mptcp_sock {
 						 * recovery related fields are under data_lock
 						 * protection
 						 */
+	u64		bytes_acked;
 	u64		snd_una;
 	u64		wnd_end;
 	unsigned long	timer_ival;
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -XXX,XX +XXX,XX @@ static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int
 
 void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 {
+	struct sock *sk = (struct sock *)msk;
 	u32 flags = 0;
+	bool slow;
 
 	memset(info, 0, sizeof(*info));
 
@@ -XXX,XX +XXX,XX @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	if (READ_ONCE(msk->can_ack))
 		flags |= MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED;
 	info->mptcpi_flags = flags;
-	info->mptcpi_token = READ_ONCE(msk->token);
-	info->mptcpi_write_seq = READ_ONCE(msk->write_seq);
-	info->mptcpi_snd_una = READ_ONCE(msk->snd_una);
-	info->mptcpi_rcv_nxt = READ_ONCE(msk->ack_seq);
-	info->mptcpi_csum_enabled = READ_ONCE(msk->csum_enabled);
+	mptcp_data_lock(sk);
+	info->mptcpi_snd_una = msk->snd_una;
+	info->mptcpi_rcv_nxt = msk->ack_seq;
+	info->mptcpi_bytes_acked = msk->bytes_acked;
+	mptcp_data_unlock(sk);
+
+	slow = lock_sock_fast(sk);
+	info->mptcpi_csum_enabled = msk->csum_enabled;
+	info->mptcpi_token = msk->token;
+	info->mptcpi_write_seq = msk->write_seq;
+	info->mptcpi_retransmits = inet_csk(sk)->icsk_retransmits;
+	info->mptcpi_bytes_sent = msk->bytes_sent;
+	info->mptcpi_bytes_received = msk->bytes_received;
+	info->mptcpi_bytes_retrans = msk->bytes_retrans;
+	unlock_sock_fast(sk, slow);
 }
 EXPORT_SYMBOL_GPL(mptcp_diag_fill_info);
 
-- 
2.40.1

Update the existing sockopt test-case to do some basic checks
on the newly added counters.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
v2 -> v3:
 - be more kind with older kernel (Matttbe)
---
 .../selftests/net/mptcp/mptcp_sockopt.c       | 27 ++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

Add a testcase explicitly triggering the newly introduce
MPTCP_FULL_INFO getsockopt.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 .../selftests/net/mptcp/mptcp_sockopt.c       | 96 ++++++++++++++++++-
 1 file changed, 94 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
index XXXXXXX..XXXXXXX 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
@@ -XXX,XX +XXX,XX @@ struct mptcp_subflow_addrs {
 #define MPTCP_SUBFLOW_ADDRS	3
 #endif
 
+#ifndef MPTCP_FULL_INFO
+struct mptcp_subflow_info {
+	__u32				id;
+	struct mptcp_subflow_addrs	addrs;
+};
+
+struct mptcp_subflow_full_info {
+	__u32		size_subflow_full_info;	/* size of this structure in userspace */
+	__u32		num_subflows_kern;	/* must be 0, set by kernel (real subflow count) */
+	__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_user;	/* max subflows that userspace is interested in;
+						 * the buffers at subflow_info_addr/tcp_info_addr
+						 * are respectively at least:
+						 *  num_subflows_user * size_sfinfo_user
+						 *  num_subflows_user * size_tcpinfo_user
+						 * bytes wide
+						 */
+	__aligned_u64	subflow_info_addr;
+	__aligned_u64	tcp_info_addr;
+};
+
+#define MPTCP_FULL_INFO		4
+#endif
+
 struct so_state {
 	struct mptcp_info mi;
 	struct mptcp_info last_sample;
+	struct tcp_info tcp_info;
+	struct mptcp_subflow_addrs addrs;
 	uint64_t mptcpi_rcv_delta;
 	uint64_t tcpi_rcv_delta;
 	bool pkt_stats_avail;
@@ -XXX,XX +XXX,XX @@ static void do_getsockopt_tcp_info(struct so_state *s, int fd, size_t r, size_t
 		olen -= sizeof(struct mptcp_subflow_data);
 		assert(olen == sizeof(struct tcp_info));
 
+		s->tcp_info = ti.ti[0];
+
 		if (ti.ti[0].tcpi_bytes_sent == w &&
 		    ti.ti[0].tcpi_bytes_received == r)
 			goto done;
@@ -XXX,XX +XXX,XX @@ static void do_getsockopt_tcp_info(struct so_state *s, int fd, size_t r, size_t
 	do_getsockopt_bogus_sf_data(fd, MPTCP_TCPINFO);
 }
 
-static void do_getsockopt_subflow_addrs(int fd)
+static void do_getsockopt_subflow_addrs(struct so_state *s, int fd)
 {
 	struct sockaddr_storage remote, local;
 	socklen_t olen, rlen, llen;
@@ -XXX,XX +XXX,XX @@ static void do_getsockopt_subflow_addrs(int fd)
 
 	assert(memcmp(&local, &addrs.addr[0].ss_local, sizeof(local)) == 0);
 	assert(memcmp(&remote, &addrs.addr[0].ss_remote, sizeof(remote)) == 0);
+	s->addrs = addrs.addr[0];
 
 	memset(&addrs, 0, sizeof(addrs));
 
@@ -XXX,XX +XXX,XX @@ static void do_getsockopt_subflow_addrs(int fd)
 	do_getsockopt_bogus_sf_data(fd, MPTCP_SUBFLOW_ADDRS);
 }
 
+struct my_mptcp_full_info {
+	struct mptcp_subflow_full_info i;
+	struct mptcp_info mi;
+};
+static void do_getsockopt_mptcp_full_info(struct so_state *s, int fd)
+{
+	size_t data_size = sizeof(struct my_mptcp_full_info);
+	struct mptcp_subflow_info sfinfo[2];
+	struct my_mptcp_full_info mmfi;
+	struct tcp_info tcp_info[2];
+	socklen_t olen;
+	int ret;
+
+	memset(&mmfi, 0, data_size);
+	memset(tcp_info, 0, sizeof(tcp_info));
+	memset(sfinfo, 0, sizeof(sfinfo));
+
+	mmfi.i.size_subflow_full_info = sizeof(struct mptcp_subflow_full_info);
+	mmfi.i.size_tcpinfo_user = sizeof(struct tcp_info);
+	mmfi.i.size_sfinfo_user = sizeof(struct mptcp_subflow_info);
+	mmfi.i.num_subflows_user = 2;
+	mmfi.i.subflow_info_addr = (unsigned long) &sfinfo[0];
+	mmfi.i.tcp_info_addr = (unsigned long) &tcp_info[0];
+	olen = data_size;
+
+	ret = getsockopt(fd, SOL_MPTCP, MPTCP_FULL_INFO, &mmfi, &olen);
+	if (ret < 0) {
+		if (errno == EOPNOTSUPP) {
+			fprintf(stderr, "\tMPTCP_FULL_INFO test skipped due to lack of kernel support\n");
+			return;
+		}
+		xerror("getsockopt MPTCP_FULL_INFO");
+	}
+
+	assert(olen <= data_size);
+	assert(mmfi.i.size_tcpinfo_user == mmfi.i.size_tcpinfo_kernel);
+	assert(mmfi.i.size_tcpinfo_user == sizeof(struct tcp_info));
+	assert(mmfi.i.size_sfinfo_user == mmfi.i.size_sfinfo_kernel);
+	assert(mmfi.i.size_sfinfo_user == sizeof(struct mptcp_subflow_info));
+	assert(mmfi.i.num_subflows_kern == 1);
+
+	/* Tolerate future extension to mptcp_info struct and running newer
+	 * test on top of older kernel.
+	 * Anyway any kernel supporting MPTCP_FULL_INFO must at least include
+	 * the following in mptcp_info.
+	 */
+	assert(olen > (socklen_t)sizeof(struct mptcp_subflow_full_info));
+	assert(mmfi.mi.mptcpi_subflows == 0);
+	assert(mmfi.mi.mptcpi_bytes_sent == s->last_sample.mptcpi_bytes_sent);
+	assert(mmfi.mi.mptcpi_bytes_received == s->last_sample.mptcpi_bytes_received);
+
+	assert(sfinfo[0].id == 1);
+	assert(tcp_info[0].tcpi_bytes_sent == s->tcp_info.tcpi_bytes_sent);
+	assert(tcp_info[0].tcpi_bytes_received == s->tcp_info.tcpi_bytes_received);
+	assert(!memcmp(&sfinfo->addrs, &s->addrs, sizeof(struct mptcp_subflow_addrs)));
+}
+
 static void do_getsockopts(struct so_state *s, int fd, size_t r, size_t w)
 {
 	do_getsockopt_mptcp_info(s, fd, w);
 
 	do_getsockopt_tcp_info(s, fd, r, w);
 
-	do_getsockopt_subflow_addrs(fd);
+	do_getsockopt_subflow_addrs(s, fd);
+
+	if (r)
+		do_getsockopt_mptcp_full_info(s, fd);
 }
 
 static void connect_one_server(int fd, int pipefd)
-- 
2.40.1

Sorry for the high-freq spamming. I really want to close this topic
and move forward.