[NET]: Adding SO_TIMESTAMPNS / SCM_TIMESTAMPNS support

Now that network timestamps use ktime_t infrastructure, we can add a new
SOL_SOCKET sockopt  SO_TIMESTAMPNS.

This command is similar to SO_TIMESTAMP, but permits transmission of
a 'timespec struct' instead of a 'timeval struct' control message.
(nanosecond resolution instead of microsecond)

Control message is labelled SCM_TIMESTAMPNS instead of SCM_TIMESTAMP

A socket cannot mix SO_TIMESTAMP and SO_TIMESTAMPNS : the two modes are
mutually exclusive.

sock_recv_timestamp() became too big to be fully inlined so I added a
__sock_recv_timestamp() helper function.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
CC: linux-arch@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 1 deletions

diff --git a/net/compat.c b/net/compat.c
index 0e407563ae85..9a0f5f2b90c8 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -215,6 +215,7 @@ Efault:
 int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *data)
 {
         struct compat_timeval ctv;
+        struct compat_timespec cts;
         struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control;
         struct compat_cmsghdr cmhdr;
         int cmlen;
@@ -229,7 +230,14 @@ int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *dat
                 ctv.tv_sec = tv->tv_sec;
                 ctv.tv_usec = tv->tv_usec;
                 data = &ctv;
-                len = sizeof(struct compat_timeval);
+                len = sizeof(ctv);
+        }
+        if (level == SOL_SOCKET && type == SO_TIMESTAMPNS) {
+                struct timespec *ts = (struct timespec *)data;
+                cts.tv_sec = ts->tv_sec;
+                cts.tv_nsec = ts->tv_nsec;
+                data = &cts;
+                len = sizeof(cts);
         }
 
         cmlen = CMSG_COMPAT_LEN(len);