Add shortcuts for setting time stamp precision

Add two shortcuts (as long-options) for setting the time stamp
precision: --micro and --nano.  While adding these options, reshuffle
the usage message to group up the options related to time stamp, and
removing the macro TIME_STAMP_PRECISION_USAGE.

If setting the time stamp precision is not supported by the available
libpcap, the usage won't mention these options (including
--time-stamp-precision), but they will still be presented in the
manpage.

1 files changed, 19 insertions, 9 deletions

diff --git a/tcpdump.c b/tcpdump.c
index 9790a4e3..c4b2c9c4 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -670,6 +670,8 @@ show_remote_devices_and_exit(void)
 #define OPTION_IMMEDIATE_MODE		130
 #define OPTION_PRINT			131
 #define OPTION_LIST_REMOTE_INTERFACES	132
+#define OPTION_TSTAMP_MICRO		133
+#define OPTION_TSTAMP_NANO		134
 
 static const struct option longopts[] = {
 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
@@ -689,6 +691,8 @@ static const struct option longopts[] = {
 	{ "list-time-stamp-types", no_argument, NULL, 'J' },
 #endif
 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
+	{ "micro", no_argument, NULL, OPTION_TSTAMP_MICRO},
+	{ "nano", no_argument, NULL, OPTION_TSTAMP_NANO},
 	{ "time-stamp-precision", required_argument, NULL, OPTION_TSTAMP_PRECISION},
 #endif
 	{ "dont-verify-checksums", no_argument, NULL, 'K' },
@@ -729,12 +733,6 @@ static const struct option longopts[] = {
 #define IMMEDIATE_MODE_USAGE ""
 #endif
 
-#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
-#define TIME_STAMP_PRECISION_USAGE " [ --time-stamp-precision precision ]"
-#else
-#define TIME_STAMP_PRECISION_USAGE
-#endif
-
 #ifndef _WIN32
 /* Drop root privileges and chroot if necessary */
 static void
@@ -1860,6 +1858,16 @@ main(int argc, char **argv)
 			print = 1;
 			break;
 
+#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
+		case OPTION_TSTAMP_MICRO:
+			ndo->ndo_tstamp_precision = PCAP_TSTAMP_PRECISION_MICRO;
+			break;
+
+		case OPTION_TSTAMP_NANO:
+			ndo->ndo_tstamp_precision = PCAP_TSTAMP_PRECISION_NANO;
+			break;
+#endif
+
 		default:
 			print_usage();
 			exit_tcpdump(S_ERR_HOST_PROGRAM);
@@ -3074,11 +3082,13 @@ print_usage(void)
 	(void)fprintf(stderr,
 "\t\t[ -M secret ] [ --number ] [ --print ]" Q_FLAG_USAGE "\n");
 	(void)fprintf(stderr,
-"\t\t[ -r file ] [ -s snaplen ]" TIME_STAMP_PRECISION_USAGE "\n");
+"\t\t[ -r file ] [ -s snaplen ] [ -T type ] [ --version ]\n");
 	(void)fprintf(stderr,
-"\t\t[ -T type ] [ --version ] [ -V file ] [ -w file ]\n");
+"\t\t[ -V file ] [ -w file ] [ -W filecount ] [ -y datalinktype ]\n");
+#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
 	(void)fprintf(stderr,
-"\t\t[ -W filecount ] [ -y datalinktype ]\n");
+"\t\t[ --time-stamp-precision precision ] [ --micro ] [ --nano ]\n");
+#endif
 	(void)fprintf(stderr,
 "\t\t[ -z postrotate-command ] [ -Z user ] [ expression ]\n");
 }