missing: add onestep sync to missing.h

this patch uses grep to test whether the net_tstamp.h header has
HWTSTAMP_TX_ONESTEP_SYNC flag defined. If it doesn't then we can simply define
it with the correct value. This works because proper drivers should just report
that the value is not allowed if they don't support onestep mode. This is the
cleanest way to ensure that linuxptp will still work on kernels which have not
defined the one step flag, and also works for any distributions which backport
the feature.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>

makefile

@@ -21,6 +21,9 @@ FEAT_CFLAGS :=
 ifneq ($(shell grep --no-messages clock_adjtime /usr/include/bits/time.h),)
 FEAT_CFLAGS += -D_GNU_SOURCE -DHAVE_CLOCK_ADJTIME
 endif
+ifneq ($(shell grep --no-messages HWTSTAMP_TX_ONESTEP_SYNC $(KBUILD_OUTPUT)/usr/include/linux/net_tstamp.h),)
+FEAT_CFLAGS += -DHAVE_ONESTEP_SYNC
+endif
 
 DEBUG	=
 CC	= $(CROSS_COMPILE)gcc

missing.h

@@ -44,6 +44,12 @@
 #define FD_TO_CLOCKID(fd)	((~(clockid_t) (fd) << 3) | CLOCKFD)
 #define CLOCKID_TO_FD(clk)	((unsigned int) ~((clk) >> 3))
 
+#ifndef HAVE_ONESTEP_SYNC
+enum _missing_hwtstamp_tx_types {
+	HWTSTAMP_TX_ONESTEP_SYNC = 2,
+}
+#endif
+
 #ifndef HAVE_CLOCK_ADJTIME
 static inline int clock_adjtime(clockid_t id, struct timex *tx)
 {