mptcp: add last time fields in mptcp_info

This patch adds "last time" fields last_data_sent, last_data_recv and
last_ack_recv in struct mptcp_sock to record the last time data_sent,
data_recv and ack_recv happened. They all are initialized as
tcp_jiffies32 in __mptcp_init_sock(), and updated as tcp_jiffies32 too
when data is sent in __subflow_push_pending(), data is received in
__mptcp_move_skbs_from_subflow(), and ack is received in ack_update_msk().

Similar to tcpi_last_data_sent, tcpi_last_data_recv and tcpi_last_ack_recv
exposed with TCP, this patch exposes the last time "an action happened" for
MPTCP in mptcp_info, named mptcpi_last_data_sent, mptcpi_last_data_recv and
mptcpi_last_ack_recv, calculated in mptcp_diag_fill_info() as the time
deltas between now and the newly added last time fields in mptcp_sock.

Since msk->last_ack_recv needs to be protected by mptcp_data_lock/unlock,
and lock_sock_fast can sleep and be quite slow, move the entire
mptcp_data_lock/unlock block after the lock/unlock_sock_fast block.
Then mptcpi_last_data_sent and mptcpi_last_data_recv are set in
lock/unlock_sock_fast block, while mptcpi_last_ack_recv is set in
mptcp_data_lock/unlock block, which is protected by a spinlock and
should not block for too long.

Also add three reserved bytes in struct mptcp_info not to have holes in
this structure exposed to userspace.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/446
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240410-upstream-net-next-20240405-mptcp-last-time-info-v2-1-f95bd6b33e51@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 74cfe496891e03098808680f00287a9336e6ed9c..67d015df8893cc1390a483bda034191525b8fef0 100644 (file)
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -58,6 +58,10 @@ struct mptcp_info {
        __u64   mptcpi_bytes_received;
        __u64   mptcpi_bytes_acked;
        __u8    mptcpi_subflows_total;
+       __u8    reserved[3];
+       __u32   mptcpi_last_data_sent;
+       __u32   mptcpi_last_data_recv;
+       __u32   mptcpi_last_ack_recv;
 };
 
 /* MPTCP Reset reason codes, rfc8684 */

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 27ca42c77b02a52fa52171922eb66fb5268d8cfc..8e8dcfbc299382454cf715a917c0f876ad5c35d4 100644 (file)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1068,6 +1068,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
                __mptcp_snd_una_update(msk, new_snd_una);
                __mptcp_data_acked(sk);
        }
+       msk->last_ack_recv = tcp_jiffies32;
        mptcp_data_unlock(sk);
 
        trace_ack_update_msk(mp_opt->data_ack,

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 995b53cd021c84e821f242ce0a679e2bff9c1937..f8bc34f0d973ebb31a63492d95be737257969d6c 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -706,6 +706,8 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
                }
        } while (more_data_avail);
 
+       if (moved > 0)
+               msk->last_data_recv = tcp_jiffies32;
        *bytes += moved;
        return done;
 }
@@ -1556,6 +1558,8 @@ static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
        err = copied;
 
 out:
+       if (err > 0)
+               msk->last_data_sent = tcp_jiffies32;
        return err;
 }
 
@@ -2793,6 +2797,9 @@ static void __mptcp_init_sock(struct sock *sk)
        WRITE_ONCE(msk->allow_infinite_fallback, true);
        msk->recovery = false;
        msk->subflow_id = 1;
+       msk->last_data_sent = tcp_jiffies32;
+       msk->last_data_recv = tcp_jiffies32;
+       msk->last_ack_recv = tcp_jiffies32;
 
        mptcp_pm_data_init(msk);
 

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 46f4655b712369ba0e4c0fa07d91d8b9741ab534..fdfa843e2d88f3e16c39772a0392d46982061693 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -282,6 +282,9 @@ struct mptcp_sock {
        u64             bytes_acked;
        u64             snd_una;
        u64             wnd_end;
+       u32             last_data_sent;
+       u32             last_data_recv;
+       u32             last_ack_recv;
        unsigned long   timer_ival;
        u32             token;
        int             rmem_released;

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 9d5d42a77bcc355468b79fd7492c92a3d7968304..1fea43f5b6f3de5f8ad54df2b791ba3649c51502 100644 (file)
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -898,6 +898,7 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
        struct sock *sk = (struct sock *)msk;
        u32 flags = 0;
        bool slow;
+       u32 now;
 
        memset(info, 0, sizeof(*info));
 
@@ -926,11 +927,6 @@ 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;
-       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 = READ_ONCE(msk->csum_enabled);
@@ -942,7 +938,17 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
        info->mptcpi_bytes_retrans = msk->bytes_retrans;
        info->mptcpi_subflows_total = info->mptcpi_subflows +
                __mptcp_has_initial_subflow(msk);
+       now = tcp_jiffies32;
+       info->mptcpi_last_data_sent = jiffies_to_msecs(now - msk->last_data_sent);
+       info->mptcpi_last_data_recv = jiffies_to_msecs(now - msk->last_data_recv);
        unlock_sock_fast(sk, slow);
+
+       mptcp_data_lock(sk);
+       info->mptcpi_last_ack_recv = jiffies_to_msecs(now - msk->last_ack_recv);
+       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);
 }
 EXPORT_SYMBOL_GPL(mptcp_diag_fill_info);