Merge branch 'cmsg_timestamp'

Soheil Hassas Yeganeh says:

====================
add TX timestamping via cmsg

This patch series aim at enabling TX timestamping via cmsg.

Currently, to occasionally sample TX timestamping on a socket,
applications need to call setsockopt twice: first for enabling
timestamps and then for disabling them. This is an unnecessary
overhead. With cmsg, in contrast, applications can sample TX
timestamps per sendmsg().

This patch series adds the code for processing SO_TIMESTAMPING
for cmsg's of the SOL_SOCKET level, and adds the glue code for
TCP, UDP, and RAW for both IPv4 and IPv6. This implementation
supports overriding timestamp generation flags (i.e.,
SOF_TIMESTAMPING_TX_*) but not timestamp reporting flags.
Applications must still enable timestamp reporting via
setsockopt to receive timestamps.

This series does not change existing timestamping behavior for
applications that are using socket options.

I will follow up with another patch to enable timestamping for
active TFO (client-side TCP Fast Open) and also setting packet
mark via cmsgs.

Thanks!

Changes in v2:
        - Replace u32 with __u32 in the documentation.

Changes in v3:
	- Fix the broken build for L2TP (due to changes
	  in IPv6).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 19 insertions, 9 deletions

diff --git a/include/net/ip.h b/include/net/ip.h
index fad74d323bd6..93725e546758 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -56,6 +56,7 @@ static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
 }
 
 struct ipcm_cookie {
+	struct sockcm_cookie	sockc;
 	__be32			addr;
 	int			oif;
 	struct ip_options_rcu	*opt;
@@ -550,7 +551,7 @@ int ip_options_rcv_srr(struct sk_buff *skb);
 
 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb, int offset);
-int ip_cmsg_send(struct net *net, struct msghdr *msg,
+int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 		 struct ipcm_cookie *ipc, bool allow_ipv6);
 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 		  unsigned int optlen);
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index d0aeb97aec5d..55ee1eb7d026 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -867,7 +867,8 @@ int ip6_append_data(struct sock *sk,
 				int odd, struct sk_buff *skb),
 		    void *from, int length, int transhdrlen, int hlimit,
 		    int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
-		    struct rt6_info *rt, unsigned int flags, int dontfrag);
+		    struct rt6_info *rt, unsigned int flags, int dontfrag,
+		    const struct sockcm_cookie *sockc);
 
 int ip6_push_pending_frames(struct sock *sk);
 
@@ -884,7 +885,8 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 			     void *from, int length, int transhdrlen,
 			     int hlimit, int tclass, struct ipv6_txoptions *opt,
 			     struct flowi6 *fl6, struct rt6_info *rt,
-			     unsigned int flags, int dontfrag);
+			     unsigned int flags, int dontfrag,
+			     const struct sockcm_cookie *sockc);
 
 static inline struct sk_buff *ip6_finish_skb(struct sock *sk)
 {
diff --git a/include/net/sock.h b/include/net/sock.h
index 255d3e03727b..e91b87f54f99 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1418,8 +1418,11 @@ void sk_send_sigurg(struct sock *sk);
 
 struct sockcm_cookie {
 	u32 mark;
+	u16 tsflags;
 };
 
+int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
+		     struct sockcm_cookie *sockc);
 int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
 		   struct sockcm_cookie *sockc);
 
@@ -2054,19 +2057,21 @@ static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
 		sk->sk_stamp = skb->tstamp;
 }
 
-void __sock_tx_timestamp(const struct sock *sk, __u8 *tx_flags);
+void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags);
 
 /**
  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
  * @sk:		socket sending this packet
+ * @tsflags:	timestamping flags to use
  * @tx_flags:	completed with instructions for time stamping
  *
  * Note : callers should take care of initial *tx_flags value (usually 0)
  */
-static inline void sock_tx_timestamp(const struct sock *sk, __u8 *tx_flags)
+static inline void sock_tx_timestamp(const struct sock *sk, __u16 tsflags,
+				     __u8 *tx_flags)
 {
-	if (unlikely(sk->sk_tsflags))
-		__sock_tx_timestamp(sk, tx_flags);
+	if (unlikely(tsflags))
+		__sock_tx_timestamp(tsflags, tx_flags);
 	if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
 		*tx_flags |= SKBTX_WIFI_STATUS;
 }
diff --git a/include/net/tcp.h b/include/net/tcp.h
index f8bb4a4ed3d1..a23282996ca9 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -754,7 +754,8 @@ struct tcp_skb_cb {
 				TCPCB_REPAIRED)
 
 	__u8		ip_dsfield;	/* IPv4 tos or IPv6 dsfield	*/
-	/* 1 byte hole */
+	__u8		txstamp_ack:1,	/* Record TX timestamp for ack? */
+			unused:7;
 	__u32		ack_seq;	/* Sequence number ACK'd	*/
 	union {
 		struct inet_skb_parm	h4;
diff --git a/include/net/transp_v6.h b/include/net/transp_v6.h
index b927413dde86..2b1c3450ab20 100644
--- a/include/net/transp_v6.h
+++ b/include/net/transp_v6.h
@@ -42,7 +42,8 @@ void ip6_datagram_recv_specific_ctl(struct sock *sk, struct msghdr *msg,
 
 int ip6_datagram_send_ctl(struct net *net, struct sock *sk, struct msghdr *msg,
 			  struct flowi6 *fl6, struct ipv6_txoptions *opt,
-			  int *hlimit, int *tclass, int *dontfrag);
+			  int *hlimit, int *tclass, int *dontfrag,
+			  struct sockcm_cookie *sockc);
 
 void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
 			     __u16 srcp, __u16 destp, int bucket);