Improve printing of refid using functions from new module mbgntp.c1.8

10 files changed, 568 insertions, 128 deletions

diff --git a/mbglib/common/mbg_ntp_test_util.c b/mbglib/common/mbg_ntp_test_util.c
index ba19d77..52c04ee 100755
--- a/mbglib/common/mbg_ntp_test_util.c
+++ b/mbglib/common/mbg_ntp_test_util.c
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: mbg_ntp_test_util.c 1.8 2017/09/06 14:04:26 martin REL_M $
+ *  $Id: mbg_ntp_test_util.c 1.9 2018/03/09 09:55:16 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,6 +10,9 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: mbg_ntp_test_util.c $
+ *  Revision 1.9  2018/03/09 09:55:16  martin
+ *  Improved printing of refid using functions from new module mbgntp.c.
+ *  Moved snprint_ntp_prec() to mbgntp.c.
  *  Revision 1.8  2017/09/06 14:04:26  martin
  *  Root delay and root dispersion are now printed
  *  with 6 instead of only 4 fractional digits.
@@ -192,61 +195,6 @@ void print_ntp_time( const char *msg, const NTP_TSTAMP *t, const char *tail, int
 
 
 /*HDR*/
-int snprint_ntp_prec( char *s, size_t max_len, int8_t prec_exp )
-{
-  typedef struct
-  {
-    double limit;
-    double scale;
-    int frac_digits;
-    const char *units;
-  } SC_INFO;
-
-  const SC_INFO *p;
-
-  int shift_cnt = abs( prec_exp );
-  double d = (double) ( (uint64_t) 1UL << shift_cnt );
-
-  if ( prec_exp < 0 )
-  {
-    int i;
-
-    #define N_SC_INFO_NEG  7
-
-    static const SC_INFO sc_info_neg[N_SC_INFO_NEG] =
-    {
-      { 1., 1e3, 0, "ms" },         // 2^^0
-      { 8., 1e3, 2, "ms" },         // 2^^3
-      { 1024., 1e6, 0, "us" },      // 2^^10
-      { 8192., 1e6, 2, "us" },      // 2^^12
-      { 524288., 1e9, 0, "ns" },    // 2^^19
-      { 8388608., 1e9, 2, "ns" },   // 2^^23
-      { 134217728., 1e9, 3, "ns" }  // 2^^27
-    };
-
-    for ( i = N_SC_INFO_NEG; i > 0; )
-    {
-      i--;
-      p = &sc_info_neg[i];
-      if ( d > p->limit )
-        break;
-    }
-
-    d = p->scale / d;
-  }
-  else
-  {
-    static const SC_INFO sc_info_pos = { 0, 0, 0, "s" };
-    p = &sc_info_pos;
-  }
-
-  return snprintf_safe( s, max_len, "%.*f %s", p->frac_digits, d, p->units );
-
-}  // snprint_ntp_prec
-
-
-
-/*HDR*/
 /**
  * @brief Print contents of an NTP packet on several lines
  *
@@ -254,21 +202,22 @@ int snprint_ntp_prec( char *s, size_t max_len, int8_t prec_exp )
  * @param[in] p    An ::NTP_PACKET_INFO structure containing the NTP packet plus some additional information.
  * @param[in] print_date_time  If not 0, print also the date and time derived from the NTP time stamps.
  */
-void print_ntp_packet( const char *msg, const NTP_PACKET_INFO *p, int print_date_time )
+void print_ntp_packet( const char *msg, const NTP_PACKET_INFO *p, int print_date_time, int verbose )
 {
   const NTP_BASE_PACKET *pbp = &p->packet.base;
   size_t i;
-  char ref_id_str[80];
-  char *cp = ref_id_str;
+  char ref_id_str_txt[5];
+  char ref_id_str_bin[16];
   int8_t pkt_precision = pbp->flags.precision;
   char prec_str[40];
+  bool refid_should_be_text = ntp_refid_should_be_text( pbp->flags.stratum, &pbp->refid );
 
   snprint_ntp_prec( prec_str, sizeof( prec_str ), pkt_precision );
 
   printf( "%s\n", msg );
 
   printf( INDENT
-    "mode %u, version %u, leap_ind %u, "
+    "mode %u, version %u, leap %u, "
     "stratum %u, poll %u, prec %i (%s)\n"
     ,
     pbp->flags.mode,
@@ -280,42 +229,36 @@ void print_ntp_packet( const char *msg, const NTP_PACKET_INFO *p, int print_date
     prec_str
   );
 
-
-  for ( i = 0; ; )
-  {
-    unsigned char uc = BYTE_OF( pbp->refid.as_u32, i );
-
-    if ( !isdigit( uc ) )
-    {
-      sprintf( ref_id_str, "%.*s",   // TODO FIXME
-               (int) sizeof( pbp->refid ),
-               pbp->refid.as_chars
-              );
-      break;
-    }
-
-    cp += sprintf( cp, "%u", uc );
-
-    if ( ++i >= sizeof( pbp->refid ) )
-    {
-      *cp = 0;
-      break;
-    }
-
-    *cp++ = '.';
-  }
+  snprintf_ntp_refid_as_text( ref_id_str_txt, sizeof( ref_id_str_txt ), &pbp->refid );
+  snprintf_ntp_refid_as_dotted_quad( ref_id_str_bin, sizeof( ref_id_str_bin ), &pbp->refid );
 
   printf(
     INDENT "root delay:      %08lX (%.6f s)\n"
     INDENT "root dispersion: %08lX (%.6f s/s)\n"
-    INDENT "reference id:    %08lX (%s)\n"
+    INDENT "reference id:    %08lX "
     ,
     (long) pbp->root_delay, _u_fp_to_d( pbp->root_delay ),
     (long) pbp->root_dispersion, _u_fp_to_d( pbp->root_dispersion ),
-    (long) pbp->refid.as_u32,
-    ref_id_str
+    (long) pbp->refid.as_u32
   );
 
+  if ( refid_should_be_text )
+  {
+    printf( "(\"%s\"", ref_id_str_txt );
+
+    if ( verbose )
+      printf( ", %s", ref_id_str_bin );
+  }
+  else  // refid is an IPv4 address or IPv6 address hash
+  {
+    printf( "(%s", ref_id_str_bin );
+
+    if ( verbose )
+      printf( ", \"%s\"", ref_id_str_txt );
+  }
+  printf( ")\n" );
+
+
   print_ntp_time( INDENT "Ref time:       ", &pbp->reference_time, newline, print_date_time );
   print_ntp_time( INDENT "Org time (T1):  ", &pbp->originate_time, newline, print_date_time );
   print_ntp_time( INDENT "Rcv time (T2):  ", &pbp->receive_time, newline, print_date_time );
@@ -546,13 +489,13 @@ void print_ntp_results( const NTP_RESULTS *p_rslt, const NTP_PACKET_INFO *p_req,
                         int print_date_time, int verbose )
 {
   if ( p_req )
-    print_ntp_packet( "Request packet:", p_req, print_date_time );
+    print_ntp_packet( "Request packet:", p_req, print_date_time, verbose );
 
   if ( p_rcv )
   {
     double d;
     bool smearing_active;
-    print_ntp_packet( "Response packet:", p_rcv, print_date_time );
+    print_ntp_packet( "Response packet:", p_rcv, print_date_time, verbose );
     smearing_active = leap_smearing_active( &p_rcv->packet.base.refid, &d );
     if ( verbose || smearing_active )
     {
diff --git a/mbglib/common/mbg_ntp_test_util.h b/mbglib/common/mbg_ntp_test_util.h
index fb2a5d4..5f303d1 100755
--- a/mbglib/common/mbg_ntp_test_util.h
+++ b/mbglib/common/mbg_ntp_test_util.h
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: mbg_ntp_test_util.h 1.5 2016/11/21 17:22:50 martin REL_M $
+ *  $Id: mbg_ntp_test_util.h 1.6 2018/03/09 09:55:33 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,6 +10,8 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: mbg_ntp_test_util.h $
+ *  Revision 1.6  2018/03/09 09:55:33  martin
+ *  Updated function prototypes.
  *  Revision 1.5  2016/11/21 17:22:50  martin
  *  Adjustable client poll value sent to server, defaults to 6.
  *  Revision 1.4  2016/08/05 12:37:31  martin
@@ -313,7 +315,6 @@ int check_bounds( int opt_val, int min_val, int max_val, int default_val )
  */
  void print_ntp_time( const char *msg, const NTP_TSTAMP *t, const char *tail, int print_date_time ) ;
 
- int snprint_ntp_prec( char *s, size_t max_len, int8_t prec_exp ) ;
  /**
  * @brief Print contents of an NTP packet on several lines
  *
@@ -321,7 +322,7 @@ int check_bounds( int opt_val, int min_val, int max_val, int default_val )
  * @param[in] p    An ::NTP_PACKET_INFO structure containing the NTP packet plus some additional information.
  * @param[in] print_date_time  If not 0, print also the date and time derived from the NTP time stamps.
  */
- void print_ntp_packet( const char *msg, const NTP_PACKET_INFO *p, int print_date_time ) ;
+ void print_ntp_packet( const char *msg, const NTP_PACKET_INFO *p, int print_date_time, int verbose ) ;
 
  /**
  * @brief Initialize a basic NTP packet
diff --git a/mbglib/common/mbgntp.c b/mbglib/common/mbgntp.c
new file mode 100755
index 0000000..007a048
--- /dev/null
+++ b/mbglib/common/mbgntp.c
@@ -0,0 +1,170 @@
+
+/**************************************************************************
+ *
+ *  $Id: mbgntp.c 1.1 2018/03/09 09:56:35 martin REL_M $
+ *
+ *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
+ *
+ *  Description:
+ *    Functions useful for NTP implementations.
+ *
+ * -----------------------------------------------------------------------
+ *  $Log: mbgntp.c $
+ *  Revision 1.1  2018/03/09 09:56:35  martin
+ *  Initial revision.
+ *
+ **************************************************************************/
+
+#define _MBGNTP
+  #include <mbgntp.h>
+#undef _MBGNTP
+
+#include <str_util.h>
+
+
+
+/*HDR*/
+/**
+ * @brief Print the value of the 'precision' field from an NTP packet to a string buffer
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in] prec_exp    The precision value from the NTP packet.
+ */
+int snprint_ntp_prec( char *s, size_t max_len, int8_t prec_exp )
+{
+  typedef struct
+  {
+    double limit;
+    double scale;
+    int frac_digits;
+    const char *units;
+  } SC_INFO;
+
+  const SC_INFO *p;
+
+  int shift_cnt = abs( prec_exp );
+  double d = (double) ( (uint64_t) 1UL << shift_cnt );
+
+  if ( prec_exp < 0 )
+  {
+    int i;
+
+    #define N_SC_INFO_NEG  7
+
+    static const SC_INFO sc_info_neg[N_SC_INFO_NEG] =
+    {
+      { 1., 1e3, 0, "ms" },         // 2^^0
+      { 8., 1e3, 2, "ms" },         // 2^^3
+      { 1024., 1e6, 0, "us" },      // 2^^10
+      { 8192., 1e6, 2, "us" },      // 2^^12
+      { 524288., 1e9, 0, "ns" },    // 2^^19
+      { 8388608., 1e9, 2, "ns" },   // 2^^23
+      { 134217728., 1e9, 3, "ns" }  // 2^^27
+    };
+
+    for ( i = N_SC_INFO_NEG; i > 0; )
+    {
+      i--;
+      p = &sc_info_neg[i];
+      if ( d > p->limit )
+        break;
+    }
+
+    d = p->scale / d;
+  }
+  else
+  {
+    static const SC_INFO sc_info_pos = { 0, 0, 0, "s" };
+    p = &sc_info_pos;
+  }
+
+  return snprintf_safe( s, max_len, "%.*f %s", p->frac_digits, d, p->units );
+
+}  // snprint_ntp_prec
+
+
+
+/*HDR*/
+/**
+ * @brief Print an NTP refid as text to a string buffer
+ *
+ * The function ::ntp_refid_should_be_text can be called to determine
+ * if the refid is to be interpreted as printable text, so this function
+ * can be used to print it into a string buffer.
+ *
+ * Please note the 4 char refid may not be 0-terminated, so you can't
+ * simply cast the original refid to a string, and then print it.
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in]   p         Pointer to a ::NTP_REFID.
+ *
+ * @return Number of characters copied to the destination buffer, without the terminating 0
+ *
+ * @see ::ntp_refid_should_be_text
+ * @see ::snprintf_ntp_refid_as_dotted_quad
+ */
+int snprintf_ntp_refid_as_text( char *s, size_t max_len, const NTP_REFID *p )
+{
+  char *cp = s;
+  int i;
+
+  for ( i = 0; i < sizeof( *p ) && i < max_len; i++ )
+  {
+    char c = p->as_chars[i];
+    *cp++ = ( c > 0x1f && c < 0x7F ) ? c : '.';
+  }
+
+  *cp = 0;  // force terminating 0
+
+  return cp - s;
+
+}  // snprintf_ntp_refid_as_text
+
+
+
+/*HDR*/
+/**
+ * @brief Print an NTP refid as dotted quad to a string buffer
+ *
+ * The function ::ntp_refid_should_be_text can be called to determine
+ * if the refid is to be interpreted as printable text, in which case
+ * ::snprintf_ntp_refid_as_text should be used to print it, or as binary
+ * number, in which case this function should be called to print it.
+ *
+ * Historically, a binary refid was always the IPv4 address of the upstream
+ * time source, so it is usually displayed as dotted quad string.
+ * Actually the upstream IP address can also be an IPv6 address which
+ * doesn't fit into the 4 byte refid field, so in case of an IPv6 address
+ * the binary refid are the 4 LSBs of the MD5 hash of the IPv6 address.
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in]   p         Pointer to a ::NTP_REFID.
+ *
+ * @return Number of characters copied to the destination buffer, without the terminating 0
+ *
+ * @see ::ntp_refid_should_be_text
+ * @see ::snprintf_ntp_refid_as_dotted_quad
+ */
+int snprintf_ntp_refid_as_dotted_quad( char *s, size_t max_len, const NTP_REFID *p )
+{
+  int n = 0;
+  int i;
+
+  for ( i = 0; ; )
+  {
+    n += snprintf_safe( &s[n], max_len - n, "%u", p->as_u8s[i] );
+
+    if ( ++i >= sizeof( *p ) )
+      break;
+
+    n += sn_cpy_str_safe( &s[n], max_len - n, "." );
+  }
+
+  return n;
+
+}  // snprintf_ntp_refid_as_dotted_quad
+
+
diff --git a/mbglib/common/mbgntp.h b/mbglib/common/mbgntp.h
index 1b00f7f..d01b90d 100755
--- a/mbglib/common/mbgntp.h
+++ b/mbglib/common/mbgntp.h
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: mbgntp.h 1.10 2017/08/15 15:45:02 martin REL_M $
+ *  $Id: mbgntp.h 1.13 2018/03/09 09:57:33 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,6 +10,14 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: mbgntp.h $
+ *  Revision 1.13  2018/03/09 09:57:33  martin
+ *  New inline function ntp_refid_should_be_text().
+ *  Updated function prototypes.
+ *  Revision 1.12  2017/12/14 16:25:19  martin
+ *  Fixed some clang compiler warnings.
+ *  Revision 1.11  2017/09/07 08:11:37  martin
+ *  Renamed NTP_FLAGS to NTP_FLAG_FIELD to avoid
+ *  a naming collision.
  *  Revision 1.10  2017/08/15 15:45:02  martin
  *  Define NSECS_PER_SEC only if it hasn't been defined before.
  *  Revision 1.9  2016/12/01 17:05:24  martin
@@ -201,7 +209,7 @@ typedef struct
   unsigned int poll      : 8;
   unsigned int precision : 8;
 
-} NTP_FLAGS;
+} NTP_FLAG_FIELD;
 
 
 
@@ -247,7 +255,7 @@ typedef union
  */
 typedef struct
 {
-  NTP_FLAGS flags;
+  NTP_FLAG_FIELD flags;
   NTP_U_FP root_delay;
   NTP_U_FP root_dispersion;
   NTP_REFID refid;
@@ -329,7 +337,7 @@ typedef struct
 static __mbg_inline /*HDR*/
 size_t get_mac_len( const NTP_PACKET_INFO *p )
 {
-  size_t mac_len = p->len - NTP_BASE_PACKET_SIZE;
+  ssize_t mac_len = p->len - NTP_BASE_PACKET_SIZE;
 
   // don't return negative values
   return ( mac_len < 0 ) ? 0 : mac_len;
@@ -348,7 +356,7 @@ size_t get_mac_len( const NTP_PACKET_INFO *p )
 static __mbg_inline /*HDR*/
 size_t get_digest_len( const NTP_PACKET_INFO *p )
 {
-  size_t digest_len = get_mac_len( p ) - sizeof( NTP_KEY_ID );
+  ssize_t digest_len = get_mac_len( p ) - sizeof( NTP_KEY_ID );
 
   // don't return negative values
   return ( digest_len < 0 ) ? 0 : digest_len;
@@ -486,6 +494,30 @@ bool leap_smearing_active( const NTP_REFID *p, double *p_offs )
 
 
 
+static __mbg_inline /*HDR*/
+/**
+ * @brief Check if the refid in an NTP packet should be ASCII text or binary
+ *
+ * Depending on the stratum number, the refid can be interpreted
+ * as ASCII string up to 4 characters, or as a binary number representing
+ * an IPv4 address or the 4 LSBs of the MD5 hash of an IPv6 address.
+ *
+ * @param[out]  p   Pointer to an ::NTP_BASE_PACKET
+ *
+ * @return true if the refid should be ASCII, else false.
+ *
+ * @see ::snprintf_ntp_refid_as_text
+ * @see ::snprintf_ntp_refid_as_dotted_quad
+ */
+bool ntp_refid_should_be_text( int stratum, const NTP_REFID *p )
+{
+  return ( stratum <= 1 || stratum >= 16 )
+         && !leap_smearing_active( p, NULL );
+
+}  // ntp_refid_should_be_text
+
+
+
 /* function prototypes: */
 
 #ifdef __cplusplus
@@ -497,7 +529,61 @@ extern "C" {
 /* This section was generated automatically */
 /* by MAKEHDR, do not remove the comments. */
 
-/* (no header definitions found) */
+ /**
+ * @brief Print the value of the 'precision' field from an NTP packet to a string buffer
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in] prec_exp    The precision value from the NTP packet.
+ */
+ int snprint_ntp_prec( char *s, size_t max_len, int8_t prec_exp ) ;
+
+ /**
+ * @brief Print an NTP refid as text to a string buffer
+ *
+ * The function ::ntp_refid_should_be_text can be called to determine
+ * if the refid is to be interpreted as printable text, so this function
+ * can be used to print it into a string buffer.
+ *
+ * Please note the 4 char refid may not be 0-terminated, so you can't
+ * simply cast the original refid to a string, and then print it.
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in]   p         Pointer to a ::NTP_REFID.
+ *
+ * @return Number of characters copied to the destination buffer, without the terminating 0
+ *
+ * @see ::ntp_refid_should_be_text
+ * @see ::snprintf_ntp_refid_as_dotted_quad
+ */
+ int snprintf_ntp_refid_as_text( char *s, size_t max_len, const NTP_REFID *p ) ;
+
+ /**
+ * @brief Print an NTP refid as dotted quad to a string buffer
+ *
+ * The function ::ntp_refid_should_be_text can be called to determine
+ * if the refid is to be interpreted as printable text, in which case
+ * ::snprintf_ntp_refid_as_text should be used to print it, or as binary
+ * number, in which case this function should be called to print it.
+ *
+ * Historically, a binary refid was always the IPv4 address of the upstream
+ * time source, so it is usually displayed as dotted quad string.
+ * Actually the upstream IP address can also be an IPv6 address which
+ * doesn't fit into the 4 byte refid field, so in case of an IPv6 address
+ * the binary refid are the 4 LSBs of the MD5 hash of the IPv6 address.
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in]   p         Pointer to a ::NTP_REFID.
+ *
+ * @return Number of characters copied to the destination buffer, without the terminating 0
+ *
+ * @see ::ntp_refid_should_be_text
+ * @see ::snprintf_ntp_refid_as_dotted_quad
+ */
+ int snprintf_ntp_refid_as_dotted_quad( char *s, size_t max_len, const NTP_REFID *p ) ;
+
 
 /* ----- function prototypes end ----- */
 
diff --git a/mbglib/common/mbgtime.h b/mbglib/common/mbgtime.h
index 02f5fd9..6ca8fd5 100755
--- a/mbglib/common/mbgtime.h
+++ b/mbglib/common/mbgtime.h
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: mbgtime.h 1.25 2017/08/15 15:48:59 martin REL_M $
+ *  $Id: mbgtime.h 1.29 2018/02/28 16:58:10 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,6 +10,15 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: mbgtime.h $
+ *  Revision 1.29  2018/02/28 16:58:10  martin
+ *  Removed reference to frac_sec_from_bin().
+ *  Revision 1.28  2018/01/15 18:18:49  martin
+ *  Renamed symbol NSECS_PER_SEC  to NSEC_PER_SEC
+ *  according to namings of similar symbols.
+ *  Revision 1.27  2017/11/29 11:14:57  gregoire
+ *  Added Multiplier MSEC_TO_NSEC_MULTIPLIER, MSEC_TO_USEC_MULTIPLIER
+ *  Revision 1.26  2017/11/16 13:33:46  philipp
+ *  Added USEC_PER_SEC define
  *  Revision 1.25  2017/08/15 15:48:59  martin
  *  Define NSECS_PER_SEC only if it hasn't been defined before.
  *  Revision 1.24  2017/07/04 14:02:25  martin
@@ -239,8 +248,12 @@ typedef struct
 #define MSEC_PER_HOUR     ( MSEC_PER_SEC * SECS_PER_HOUR )
 #define MSEC_PER_DAY      ( MSEC_PER_SEC * SECS_PER_DAY )
 
-#if !defined( NSECS_PER_SEC )
-  #define NSECS_PER_SEC   1000000000L
+#if !defined( USEC_PER_SEC )
+  #define USEC_PER_SEC    1000000L
+#endif
+
+#if !defined( NSEC_PER_SEC )
+  #define NSEC_PER_SEC   1000000000L
 #endif
 
 #if !defined( HNS_PER_SEC )
@@ -252,6 +265,10 @@ typedef struct
 #endif
 
 
+#define MSEC_TO_NSEC_MULTIPLIER    ( NSEC_PER_SEC / MSEC_PER_SEC )
+#define MSEC_TO_USEC_MULTIPLIER    ( USEC_PER_SEC / MSEC_PER_SEC )
+
+
 /**
  * @brief A table with the days of month
  *
@@ -384,7 +401,6 @@ _ext DAYS_OF_MONTH_TABLE days_of_month
  * @see ::dec_frac_to_bin_frac_16
  * @see ::dec_frac_to_bin_frac_32
  * @see ::bin_frac_32_to_dec_frac
- * @see ::frac_sec_from_bin
  */
 static __mbg_inline
 uint32_t bin_frac_16_to_dec_frac( uint16_t bin, uint32_t scale )
diff --git a/mbglib/common/timeutil.c b/mbglib/common/timeutil.c
index a239f04..ec42d02 100755
--- a/mbglib/common/timeutil.c
+++ b/mbglib/common/timeutil.c
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: timeutil.c 1.3 2017/08/24 13:51:48 martin REL_M $
+ *  $Id: timeutil.c 1.7 2018/01/30 09:51:35 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,6 +10,17 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: timeutil.c $
+ *  Revision 1.7  2018/01/30 09:51:35  martin
+ *  Let snprint_gmtime_error() return an int instead of size_t.
+ *  Updated mbg_clock_gettime():
+ *  Revision 1.6  2018/01/15 18:31:08Z  martin
+ *  Account for renamed library symbol NSEC_PER_SEC.
+ *  Moved function snprint_utc_offs() here.
+ *  Changed return type of some printing functions to int.
+ *  Revision 1.5  2017/11/16 13:34:09  philipp
+ *  Extended ISO printing helper functions
+ *  Revision 1.4  2017/11/16 11:33:28  philipp
+ *  Added functions to print a time_t to ISO format
  *  Revision 1.3  2017/08/24 13:51:48  martin
  *  Fixed a xcompiler warning under Windows (x64).
  *  Revision 1.2  2017/07/05 07:10:48Z  martin
@@ -28,30 +39,29 @@
 #include <str_util.h>
 
 #if defined( MBG_TGT_WIN32 )
-  #include <mbgerror.h>  // NSECS_PER_SEC
   #include <stdio.h>
 #endif
 
 
 
 /*HDR*/
-size_t snprint_gmtime_error( char *s, size_t max_len, int mbg_errno, time_t t, const char *calling_fnc )
+int snprint_gmtime_error( char *s, size_t max_len, int mbg_errno, time_t t, const char *calling_fnc )
 {
   size_t n = snprintf_safe( s, max_len, "gmtime() call failed" );
 
   if ( calling_fnc )
     n += snprintf_safe( &s[n], max_len - n, " in %s", calling_fnc );
 
-  #if defined( _MSC_VER ) && ( _MSC_VER < 1500 )
+  #if defined( MBG_TGT_MISSING_64_BIT_TYPES )
     //### TODO E.g. in VC6 time_t is only 32 bit anyway.
     n += snprintf_safe( &s[n], max_len - n, " for time_t %lu: %s",
                         (unsigned long) t, mbg_strerror( mbg_errno ) );
   #else
-    n += snprintf_safe( &s[n], max_len - n, " for time_t %llu: %s",
-                        (unsigned long long) t, mbg_strerror( mbg_errno ) );
+    n += snprintf_safe( &s[n], max_len - n, " for time_t %" PRIu64 ": %s",
+                        (uint64_t) t, mbg_strerror( mbg_errno ) );
   #endif
 
-  return n;
+  return _int_from_size_t( n );
 
 }  // snprint_gmtime_error
 
@@ -67,11 +77,30 @@ typedef int clockid_t;
 /*HDR*/
 int mbg_clock_gettime( clockid_t clock_id, struct timespec *tp )
 {
+  // FIXME TODO Should we return a POSIX-compatible return code
+  // with 0 for success and -1 indicating an error?
+  //
+  // If we'd do we had to set "errno" or the value returned
+  // by Windows' GetLastError() to some specific error code
+  // that can be retrieved by the application. However, there's
+  // a problem when timespec_get() is used to implement this.
+
+  // On success, timespec_get() returns the value of the "base"
+  // parameter that has been passed to timespec_get(), e.g.
+  // TIME_UTC. On error, it returns 0, but the usual docs for
+  // timespec_get() don't mention if there's a way to determine
+  // the reason for the failure, e.g. by retrieving a value
+  // from"errno" or so.
+  //
+  // So for now we return 0 on success as usual, and -1
+  // on error, but the caller is unable to determine the
+  // reason for the fauilure.
+
   if ( clock_id == CLOCK_REALTIME )
   {
     #if defined( TIME_UTC )  // C11 / VS2015+
-      int rc = timespec_get( tp, TIME_UTC );  // TODO Check this code
-      return ( rc == 0 ) ? -1 : 0   // rc == 0 means error
+      int rc = timespec_get( tp, TIME_UTC );
+      return ( rc == 0 ) ? -1 : 0;
     #else
       #define EPOCH_HNS     116444736000000000i64
       FILETIME ft;
@@ -80,13 +109,13 @@ int mbg_clock_gettime( clockid_t clock_id, struct timespec *tp )
       tmp = ( (__int64) ft.dwHighDateTime << 32 ) | ft.dwLowDateTime;
       tmp -= EPOCH_HNS;   // convert to Unix epoch
       tmp *= 100;         // convert to nanoseconds
-      tp->tv_sec = ( tmp / NSECS_PER_SEC );
-      tp->tv_nsec = (long) ( tmp % NSECS_PER_SEC );
+      tp->tv_sec = ( tmp / NSEC_PER_SEC );
+      tp->tv_nsec = (long) ( tmp % NSEC_PER_SEC );
       return 0;
     #endif
   }
   else
-    return -1;    // TODO this is e.g. in case of CLOCK_MONOTONIC, we could use QPC then.
+    return -1;  // TODO this is e.g. in case of CLOCK_MONOTONIC, we could use QPC then.
 
 }  // mbg_clock_gettime
 
@@ -109,8 +138,8 @@ int mbg_clock_settime( clockid_t clock_id, const struct timespec *tp )
       tmp = ( (__int64) ft.dwHighDateTime << 32 ) | ft.dwLowDateTime;
       tmp -= EPOCH_HNS;   // convert to Unix epoch
       tmp *= 100;         // convert to nanoseconds
-      res->tv_sec = ( tmp / NSECS_PER_SEC );
-      res->tv_nsec = ( tmp % NSECS_PER_SEC );
+      res->tv_sec = ( tmp / NSEC_PER_SEC );
+      res->tv_nsec = ( tmp % NSEC_PER_SEC );
       return 0;
     #endif
 #endif
@@ -164,3 +193,162 @@ out:
 
 #endif
 
+
+
+/*HDR*/
+/**
+ * @brief Print a UTC offset into a string
+ *
+ * Format of the string is "[info]+hh[:mm[:ss]]h"
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in]   info      An optional info string to be prepended, may be NULL.
+ * @param[in]   utc_offs  The UTC offset to be printed, in [s].
+ *
+ * @return The number of characters written to the output buffer, except the terminating 0.
+ */
+int snprint_utc_offs( char *s, size_t max_len, const char *info, long utc_offs )
+{
+  size_t n = 0;
+
+  // utc_offs is in [s]
+  char utc_offs_sign = ( utc_offs < 0 ) ? '-' : '+';
+  ulong abs_utc_offs = labs( utc_offs );
+  ulong utc_offs_hours = abs_utc_offs / SECS_PER_HOUR;
+  ulong tmp = abs_utc_offs % SECS_PER_HOUR;
+  ulong utc_offs_mins = tmp / MINS_PER_HOUR;
+  ulong utc_offs_secs = tmp % MINS_PER_HOUR;
+
+  if ( info )
+    n += snprintf_safe( &s[n], max_len - n, "%s", info );
+
+  n += snprintf_safe( &s[n], max_len - n, "%c%lu", utc_offs_sign, utc_offs_hours );
+
+  if ( utc_offs_mins || utc_offs_secs )
+    n += snprintf_safe( &s[n], max_len - n, ":%02lu", utc_offs_mins );
+
+  if ( utc_offs_secs )
+    n += snprintf_safe( &s[n], max_len - n, ":%02lu", utc_offs_secs );
+
+  n += sn_cpy_str_safe( &s[n], max_len - n, "h" );
+
+  return _int_from_size_t( n );
+
+}  // snprint_utc_offs
+
+
+
+/*HDR*/
+int snprint_time_t_to_iso( time_t tstamp, int offs_hours, char *buf, size_t len )
+{
+  struct tm tm = { 0 };
+  size_t n;
+  int rc;
+
+  if ( offs_hours )
+    tstamp += offs_hours * SECS_PER_HOUR;
+
+  rc = mbg_gmtime( &tm, &tstamp );
+
+  if ( mbg_rc_is_error( rc ) )
+  {
+    // TODO Error: conversion failed.
+  }
+
+  n = snprintf_safe( buf, len, "%04d-%02d-%02d, %02d:%02d:%02d",
+                     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+                     tm.tm_hour, tm.tm_min, tm.tm_sec );
+
+  return _int_from_size_t( n );
+
+}  // snprint_time_t_to_iso
+
+
+
+static __mbg_inline /*HDR*/
+int __to_iso_frac( time_t tstamp, int offset, time_t frac,
+                   const char* fmt, char *buf, size_t max_len )
+{
+  size_t n = snprint_time_t_to_iso( tstamp, offset, buf, max_len );
+  n += snprintf_safe( &buf[n], max_len - n, fmt, frac );
+
+  return _int_from_size_t( n );
+
+}  // __to_iso_frac
+
+
+
+/*HDR*/
+int snprint_time_t_to_iso_ms( time_t tstamp, int offs_hours, time_t frac,
+                              char *buf, size_t len )
+{
+  tstamp += frac / MSEC_PER_SEC;
+  frac %= MSEC_PER_SEC;
+
+  return __to_iso_frac( tstamp, offs_hours, frac, ".%03lu", buf, len );
+
+}  // snprint_time_t_to_iso_ms
+
+
+
+/*HDR*/
+int snprint_time_t_to_iso_us( time_t tstamp, int offs_hours, time_t frac,
+                                char *buf, size_t len )
+{
+  tstamp += frac / USEC_PER_SEC;
+  frac %= USEC_PER_SEC;
+
+  return __to_iso_frac( tstamp, offs_hours, frac, ".%06lu", buf, len );
+
+}  // snprint_time_t_to_iso_us
+
+
+
+/*HDR*/
+int snprint_time_t_to_iso_ns( time_t tstamp, int offs_hours, time_t frac,
+                              char *buf, size_t len )
+{
+  tstamp += frac / NSEC_PER_SEC;
+  frac %= NSEC_PER_SEC;
+
+  return __to_iso_frac( tstamp, offs_hours, frac, ".%09lu", buf, len );
+
+}  // snprint_time_t_to_iso_ns
+
+
+
+/*HDR*/
+int snprint_ntp_tstamp_to_iso_ms( const NTP_TSTAMP *ts, char *buf, size_t len )
+{
+  time_t secs = cvt_to_time_t( ts->seconds ) - NTP_SEC_BIAS;
+  time_t fracs = bin_frac_32_to_msec( ts->fractions );
+
+  return snprint_time_t_to_iso_ms( secs, 0, fracs, buf, len );
+
+}  // snprint_ntp_tstamp_to_iso_ms
+
+
+
+/*HDR*/
+int snprint_ntp_tstamp_to_iso_us( const NTP_TSTAMP *ts, char *buf, size_t len )
+{
+  time_t secs = cvt_to_time_t( ts->seconds ) - NTP_SEC_BIAS;
+  time_t fracs = bin_frac_32_to_usec( ts->fractions );
+
+  return snprint_time_t_to_iso_us( secs, 0, fracs, buf, len );
+
+}  // snprint_ntp_tstamp_to_iso_us
+
+
+
+/*HDR*/
+int snprint_ntp_tstamp_to_iso_ns( const NTP_TSTAMP *ts, char *buf, size_t len )
+{
+  time_t secs = cvt_to_time_t( ts->seconds ) - NTP_SEC_BIAS;
+  time_t fracs = bin_frac_32_to_nsec( ts->fractions );
+
+  return snprint_time_t_to_iso_ns( secs, 0, fracs, buf, len );
+
+}  // snprint_ntp_tstamp_to_iso_ns
+
diff --git a/mbglib/common/timeutil.h b/mbglib/common/timeutil.h
index 233c174..517a725 100755
--- a/mbglib/common/timeutil.h
+++ b/mbglib/common/timeutil.h
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: timeutil.h 1.3 2017/07/05 07:15:00 martin REL_M $
+ *  $Id: timeutil.h 1.7 2018/01/30 09:54:12 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,6 +10,14 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: timeutil.h $
+ *  Revision 1.7  2018/01/30 09:54:12  martin
+ *  Updated function prototypes.
+ *  Revision 1.6  2018/01/15 18:31:21Z  martin
+ *  Updated function prototypes.
+ *  Revision 1.5  2017/11/16 13:34:09  philipp
+ *  Extended ISO printing helper functions
+ *  Revision 1.4  2017/11/16 11:33:28  philipp
+ *  Added functions to print a time_t to ISO format
  *  Revision 1.3  2017/07/05 07:15:00  martin
  *  Provide basic support for clock_gettime()/clock_settime()
  *  compatible functions for Windows.
@@ -24,7 +32,7 @@
 
 /* Other headers to be included */
 
-#include <words.h>  // implicitly includes mbg_tgt.h for non-firmware projects
+#include <gpsdefs.h>
 #include <mbgerror.h>
 
 #include <time.h>
@@ -109,10 +117,31 @@ int mbg_gmtime( struct tm *p_tm, const time_t *p_time )
 /* This section was generated automatically */
 /* by MAKEHDR, do not remove the comments. */
 
- size_t snprint_gmtime_error( char *s, size_t max_len, int mbg_errno, time_t t, const char *calling_fnc ) ;
+ int snprint_gmtime_error( char *s, size_t max_len, int mbg_errno, time_t t, const char *calling_fnc ) ;
  int mbg_clock_gettime( clockid_t clock_id, struct timespec *tp ) ;
  int mbg_clock_settime( clockid_t clock_id, const struct timespec *tp ) ;
  void check_precise_time_api( void ) ;
+ /**
+ * @brief Print a UTC offset into a string
+ *
+ * Format of the string is "[info]+hh[:mm[:ss]]h"
+ *
+ * @param[out]  s         Address of a string buffer to be filled.
+ * @param[in]   max_len   Size of the string buffer.
+ * @param[in]   info      An optional info string to be prepended, may be NULL.
+ * @param[in]   utc_offs  The UTC offset to be printed, in [s].
+ *
+ * @return The number of characters written to the output buffer, except the terminating 0.
+ */
+ int snprint_utc_offs( char *s, size_t max_len, const char *info, long utc_offs ) ;
+
+ int snprint_time_t_to_iso( time_t tstamp, int offs_hours, char *buf, size_t len ) ;
+ int snprint_time_t_to_iso_ms( time_t tstamp, int offs_hours, time_t frac, char *buf, size_t len ) ;
+ int snprint_time_t_to_iso_us( time_t tstamp, int offs_hours, time_t frac, char *buf, size_t len ) ;
+ int snprint_time_t_to_iso_ns( time_t tstamp, int offs_hours, time_t frac, char *buf, size_t len ) ;
+ int snprint_ntp_tstamp_to_iso_ms( const NTP_TSTAMP *ts, char *buf, size_t len ) ;
+ int snprint_ntp_tstamp_to_iso_us( const NTP_TSTAMP *ts, char *buf, size_t len ) ;
+ int snprint_ntp_tstamp_to_iso_ns( const NTP_TSTAMP *ts, char *buf, size_t len ) ;
 
 /* ----- function prototypes end ----- */
 
diff --git a/mbglib/common/words.h b/mbglib/common/words.h
index 9cbc841..3d4f2d5 100755
--- a/mbglib/common/words.h
+++ b/mbglib/common/words.h
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: words.h 1.42 2017/07/26 14:28:50 martin REL_M $
+ *  $Id: words.h 1.43 2018/01/29 10:30:23 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -10,7 +10,9 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: words.h $
- *  Revision 1.42  2017/07/26 14:28:50  martin
+ *  Revision 1.43  2018/01/29 10:30:23  martin
+ *  Modified some comments.
+ *  Revision 1.42  2017/07/26 14:28:50Z  martin
  *  Fixed build for NetBSD.
  *  Revision 1.41  2017/07/05 12:06:35  martin
  *  Moved macro _int_from_size_t() here.
@@ -223,7 +225,7 @@
   #if defined( MBG_TGT_MISSING_64_BIT_TYPES )
 
     // The build environment does not support 64 bit types. However,
-    // 64 bit types need to be defined to avoid build errors
+    // 64 bit types need to be defined to avoid build errors e.g.
     // if these types are formally used in function prototypes.
     // We explicitly use abnormal data types to hopefully
     // cause compiler errors in case these types are
@@ -235,8 +237,8 @@
   #else
 
     // Define C99 types using non-standard exact-size types
-    // which are usually supported by build envonronments
-    // supporting 64 bit types but no C99 types.
+    // which are usually supported by build environments that
+    // support 64 bit types but don't support C99 types.
     typedef __int64 int64_t;
     typedef unsigned __int64 uint64_t;
 
diff --git a/ntptest.c b/ntptest.c
index f9be4f0..dbc0581 100755
--- a/ntptest.c
+++ b/ntptest.c
@@ -1,7 +1,7 @@
 
 /**************************************************************************
  *
- *  $Id: ntptest.c 1.11 2017/09/06 14:26:59 martin REL_M $
+ *  $Id: ntptest.c 1.12 2018/03/09 09:59:29 martin REL_M $
  *
  *  Copyright (c) Meinberg Funkuhren, Bad Pyrmont, Germany
  *
@@ -12,6 +12,8 @@
  *
  * -----------------------------------------------------------------------
  *  $Log: ntptest.c $
+ *  Revision 1.12  2018/03/09 09:59:29  martin
+ *  Updated version number to 1.8 and copyright year to 2018.
  *  Revision 1.11  2017/09/06 14:26:59  martin
  *  Support build under Windows.
  *  Revision 1.10  2017/09/06 14:14:40Z  martin
@@ -70,8 +72,8 @@
 
 static const char program_name[] = "ntptest";
 
-static const char program_version[] = "v1.7";
-static const char program_copyright[] = "(c) Meinberg 2014-2017";
+static const char program_version[] = "v1.8";
+static const char program_copyright[] = "(c) Meinberg 2014-2018";
 static const char program_contact[] = "contact: <martin.burnicki@meinberg.de>";
 
 
diff --git a/unix/Makefile b/unix/Makefile
index cc0cdb2..9ad5b1d 100755
--- a/unix/Makefile
+++ b/unix/Makefile
@@ -1,13 +1,15 @@
 
 #########################################################################
 #
-#  $Id: Makefile 1.2 2016/08/05 12:40:28 martin REL_M $
+#  $Id: Makefile 1.4 2018/03/09 09:58:03 martin REL_M $
 #
 #  Description:
 #    Makefile for ntptest.
 #
 # -----------------------------------------------------------------------
 #  $Log: Makefile $
+#  Revision 1.4  2018/03/09 09:58:03  martin
+#  Added new module mbgntp.o.
 #  Revision 1.2  2016/08/05 12:40:28  martin
 #  Account for modified directory structure.
 #  Makefile has been moved to subdirectory unix/.
@@ -23,6 +25,7 @@ MBGLIB = ../mbglib
 MBGLIB_DIRS = common
 
 OBJS = $(TARGET).o
+OBJS += mbgntp.o
 OBJS += mbg_ntp_test_util.o
 OBJS += timeutil.o
 OBJS += str_util.o