20 files changed, 90 insertions, 5 deletions

diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 671cccf0dcd2..96f50694a748 100644
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -182,6 +182,16 @@ SOF_TIMESTAMPING_OPT_TSONLY:
   the timestamp even if sysctl net.core.tstamp_allow_data is 0.
   This option disables SOF_TIMESTAMPING_OPT_CMSG.
 
+SOF_TIMESTAMPING_OPT_STATS:
+
+  Optional stats that are obtained along with the transmit timestamps.
+  It must be used together with SOF_TIMESTAMPING_OPT_TSONLY. When the
+  transmit timestamp is available, the stats are available in a
+  separate control message of type SCM_TIMESTAMPING_OPT_STATS, as a
+  list of TLVs (struct nlattr) of types. These stats allow the
+  application to associate various transport layer stats with
+  the transmit timestamps, such as how long a certain block of
+  data was limited by peer's receiver window.
 
 New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to
 disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate
diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 9e46d6e656d9..afc901b7a6f6 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -97,4 +97,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index afbc98f02d27..81e03530ed39 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -90,5 +90,7 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index 0018fad9039f..57feb0c1f7d7 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -99,4 +99,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 5fe42fc7b6c5..5853f8e92c20 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -90,4 +90,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 2027240aafbb..566ecdcb5b4b 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -108,4 +108,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index 5129f23a9ee1..0e12527c4b0e 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -90,4 +90,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index 9c935d717df9..7a109b73ddf7 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -89,4 +89,6 @@
 
 #define SO_CNX_ADVICE           0x402E
 
+#define SCM_TIMESTAMPING_OPT_STATS      0x402F
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index 1672e3398270..44583a52f882 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -97,4 +97,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif  /* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index 41b51c2f4f1b..b24a64cbfeb1 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -96,4 +96,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 31aede3af088..a25dc32f5d6a 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -86,6 +86,8 @@
 
 #define SO_CNX_ADVICE           0x0037
 
+#define SCM_TIMESTAMPING_OPT_STATS      0x0038
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION              0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT        0x5002
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 81435d995e11..9fdbe1fe0473 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -101,4 +101,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif  /* _XTENSA_SOCKET_H */
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index d5d3bd814338..00e0ee8f001f 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -428,4 +428,6 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp)
         tp->saved_syn = NULL;
 }
 
+struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk);
+
 #endif  /* _LINUX_TCP_H */
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 67d632f1743d..2c748ddad5f8 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -92,4 +92,6 @@
 
 #define SO_CNX_ADVICE           53
 
+#define SCM_TIMESTAMPING_OPT_STATS      54
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
index 264e515de16f..464dcca5ed68 100644
--- a/include/uapi/linux/net_tstamp.h
+++ b/include/uapi/linux/net_tstamp.h
@@ -25,8 +25,9 @@ enum {
         SOF_TIMESTAMPING_TX_ACK = (1<<9),
         SOF_TIMESTAMPING_OPT_CMSG = (1<<10),
         SOF_TIMESTAMPING_OPT_TSONLY = (1<<11),
+        SOF_TIMESTAMPING_OPT_STATS = (1<<12),
 
-        SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_TSONLY,
+        SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_STATS,
         SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |
                                  SOF_TIMESTAMPING_LAST
 };
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 2863b661d6e1..c53de2691cec 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -220,6 +220,14 @@ struct tcp_info {
         __u64   tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
 };
 
+/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
+enum {
+        TCP_NLA_PAD,
+        TCP_NLA_BUSY,           /* Time (usec) busy sending data */
+        TCP_NLA_RWND_LIMITED,   /* Time (usec) limited by receive window */
+        TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
+};
+
 /* for TCP_MD5SIG socket option */
 #define TCP_MD5SIG_MAXKEYLEN    80
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d1d1a5a5ad24..ea6fa954c7a0 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3839,10 +3839,18 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
         if (!skb_may_tx_timestamp(sk, tsonly))
                 return;
 
-        if (tsonly)
-                skb = alloc_skb(0, GFP_ATOMIC);
-        else
+        if (tsonly) {
+#ifdef CONFIG_INET
+                if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
+                    sk->sk_protocol == IPPROTO_TCP &&
+                    sk->sk_type == SOCK_STREAM)
+                        skb = tcp_get_timestamping_opt_stats(sk);
+                else
+#endif
+                        skb = alloc_skb(0, GFP_ATOMIC);
+        } else {
                 skb = skb_clone(orig_skb, GFP_ATOMIC);
+        }
         if (!skb)
                 return;
 
diff --git a/net/core/sock.c b/net/core/sock.c
index 14e6145be33b..d8c7f8c877ca 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -854,6 +854,13 @@ set_rcvbuf:
                                 sk->sk_tskey = 0;
                         }
                 }
+
+                if (val & SOF_TIMESTAMPING_OPT_STATS &&
+                    !(val & SOF_TIMESTAMPING_OPT_TSONLY)) {
+                        ret = -EINVAL;
+                        break;
+                }
+
                 sk->sk_tsflags = val;
                 if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
                         sock_enable_timestamp(sk,
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index cdde20f49999..1149b48700a1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2841,6 +2841,26 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
 }
 EXPORT_SYMBOL_GPL(tcp_get_info);
 
+struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
+{
+        const struct tcp_sock *tp = tcp_sk(sk);
+        struct sk_buff *stats;
+        struct tcp_info info;
+
+        stats = alloc_skb(3 * nla_total_size_64bit(sizeof(u64)), GFP_ATOMIC);
+        if (!stats)
+                return NULL;
+
+        tcp_get_info_chrono_stats(tp, &info);
+        nla_put_u64_64bit(stats, TCP_NLA_BUSY,
+                          info.tcpi_busy_time, TCP_NLA_PAD);
+        nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED,
+                          info.tcpi_rwnd_limited, TCP_NLA_PAD);
+        nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED,
+                          info.tcpi_sndbuf_limited, TCP_NLA_PAD);
+        return stats;
+}
+
 static int do_tcp_getsockopt(struct sock *sk, int level,
                 int optname, char __user *optval, int __user *optlen)
 {
diff --git a/net/socket.c b/net/socket.c
index e2584c51aa1f..e6318943ad07 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -693,9 +693,14 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
             (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
             ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2))
                 empty = 0;
-        if (!empty)
+        if (!empty) {
                 put_cmsg(msg, SOL_SOCKET,
                          SCM_TIMESTAMPING, sizeof(tss), &tss);
+
+                if (skb->len && (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS))
+                        put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS,
+                                 skb->len, skb->data);
+        }
 }
 EXPORT_SYMBOL_GPL(__sock_recv_timestamp);