mptcp: receive path cmsg support

This adds support for SO_TIMESTAMP(NS).  Timestamps are passed to
userspace in the same way as for plain tcp sockets.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 2bc1995..3897d35 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -39,10 +39,15 @@ struct mptcp_skb_cb {
        u64 map_seq;
        u64 end_seq;
        u32 offset;
+       u8  has_rxtstamp:1;
 };
 
 #define MPTCP_SKB_CB(__skb)    ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
 
+enum {
+       MPTCP_CMSG_TS = BIT(0),
+};
+
 static struct percpu_counter mptcp_sockets_allocated;
 
 static void __mptcp_destroy_sock(struct sock *sk);
@@ -272,6 +277,7 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
        struct sock *sk = (struct sock *)msk;
        struct sk_buff *tail;
+       bool has_rxtstamp;
 
        __skb_unlink(skb, &ssk->sk_receive_queue);
 
@@ -287,6 +293,8 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
                        goto drop;
        }
 
+       has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
+
        /* the skb map_seq accounts for the skb offset:
         * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
         * value
@@ -294,6 +302,7 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
        MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
        MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
        MPTCP_SKB_CB(skb)->offset = offset;
+       MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
 
        if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
                /* in sequence */
@@ -1757,7 +1766,9 @@ static void mptcp_wait_data(struct sock *sk, long *timeo)
 
 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
                                struct msghdr *msg,
-                               size_t len, int flags)
+                               size_t len, int flags,
+                               struct scm_timestamping_internal *tss,
+                               int *cmsg_flags)
 {
        struct sk_buff *skb, *tmp;
        int copied = 0;
@@ -1777,6 +1788,11 @@ static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
                        }
                }
 
+               if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
+                       tcp_update_recv_tstamps(skb, tss);
+                       *cmsg_flags |= MPTCP_CMSG_TS;
+               }
+
                copied += count;
 
                if (count < data_len) {
@@ -1964,7 +1980,8 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
                         int nonblock, int flags, int *addr_len)
 {
        struct mptcp_sock *msk = mptcp_sk(sk);
-       int copied = 0;
+       struct scm_timestamping_internal tss;
+       int copied = 0, cmsg_flags = 0;
        int target;
        long timeo;
 
@@ -1986,7 +2003,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
        while (copied < len) {
                int bytes_read;
 
-               bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags);
+               bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
                if (unlikely(bytes_read < 0)) {
                        if (!copied)
                                copied = bytes_read;
@@ -2067,6 +2084,11 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
                set_bit(MPTCP_DATA_READY, &msk->flags);
        }
 out_err:
+       if (cmsg_flags && copied >= 0) {
+               if (cmsg_flags & MPTCP_CMSG_TS)
+                       tcp_recv_timestamp(msg, sk, &tss);
+       }
+
        pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",
                 msk, test_bit(MPTCP_DATA_READY, &msk->flags),
                 skb_queue_empty_lockless(&sk->sk_receive_queue), copied);