Revert "changed timer source (#522)" (#536)

This reverts commit 0298efa36e.

Makefile.in

@@ -48,8 +48,8 @@ N2N_LIB=libn2n.a
 N2N_OBJS=$(patsubst src/%.c, src/%.o, $(wildcard src/*.c))
 N2N_DEPS=$(wildcard include/*.h) $(wildcard src/*.c) Makefile $(N2N_LIB)
 
-LIBS_EDGE+=-lrt $(LIBS_EDGE_OPT)
-LIBS_SN=-lrt
+LIBS_EDGE+=$(LIBS_EDGE_OPT)
+LIBS_SN=
 
 #For OpenSolaris (Solaris too?)
 ifeq ($(shell uname), SunOS)

include/n2n.h

@@ -54,6 +54,7 @@
 
 #define PACKAGE_BUILDDATE (__DATE__ " " __TIME__)
 
+#include <time.h>
 #include <ctype.h>
 #include <stdlib.h>
 
@@ -120,7 +121,6 @@
 #define closesocket(a) close(a)
 #endif /* #ifndef WIN32 */
 
-#include <time.h> /* should be included after eventually including unistd.h for _POSIX_TIMERS macro gets correctly defined */
 #include "minilzo.h"
 #include <signal.h>
 #include <string.h>

src/n2n.c

@@ -546,31 +546,19 @@ int gettimeofday(struct timeval *tp, void *tzp) {
 // returns a time stamp for use with replay protection
 uint64_t time_stamp (void) {
 
+  struct timeval tod;
   uint64_t micro_seconds;
-#if defined (_POSIX_TIMERS)
-  struct timespec t;
-  clock_gettime(CLOCK_REALTIME, &t);
-#else
-  struct timeval t;
-  gettimeofday (&t, NULL);
-#endif
 
+  gettimeofday (&tod, NULL);
   /* We will (roughly) calculate the microseconds since 1970 leftbound into the return value.
      The leading 32 bits are used for tv_sec. The following 20 bits (sufficent as microseconds
-     fraction never exceeds 1,000,000,) encode the value tv_nsec/1024 ( ~ usec) or tv_usec
-     respectively. The remaining lowest 12 bits are kept random for use in IV */
-  micro_seconds  = (uint64_t)(t.tv_sec) << 32;
-#if defined (_POSIX_TIMERS)
-  micro_seconds += (t.tv_nsec >> 10) << 12;
-#else
-  micro_seconds += t.tv_usec << 12;
-#endif
-  micro_seconds |= (uint64_t)n2n_rand() >> 52;
-
-  // to do the following would be more exact but also
-  // more costly due to the multiplication and divison:
-  // micro_seconds = (t.tv_sec * 1000000 + t.tv_nsec / 1000) << 12) | ... or
-  // micro_seconds = (t.tv_sec * 1000000 + t.tv_usec)        << 12) | ...
+     fraction never exceeds 1,000,000,) encode the value tv_usec. The remaining lowest 12 bits
+     are kept random for use in IV */
+  micro_seconds = n2n_rand();
+  micro_seconds = ( (((uint64_t)(tod.tv_sec) << 32) + (tod.tv_usec << 12))
+                  |  (micro_seconds >> 52) );
+  // more exact but more costly due to the multiplication:
+  // micro_seconds = (tod.tv_sec * 1000000 + tod.tv_usec) << 12) | ...
 
   return (micro_seconds);
 }