[PATCH 1/4] monitor: add --time-format,-t option

[James Prestwood <prestwoj@gmail.com>]

For syncing iwmon captures with other logging its useful to
timestamp in some absolute format like UTC. This adds an
option which allows the user to specify what time format to
show. For now support:

delta - (default) The time delta between the first packet
        and the current packet.
utc   - The packet time in UTC
---
 monitor/main.c  | 56 ++++++++++++++++++++++++++++++-------------------
 monitor/nlmon.c | 40 +++++++++++++++++++++++++++++------
 monitor/nlmon.h |  6 ++++++
 3 files changed, 75 insertions(+), 27 deletions(-)

diff --git a/monitor/main.c b/monitor/main.c
index fc22c777..fe40e301 100644
--- a/monitor/main.c
+++ b/monitor/main.c
@@ -718,29 +718,32 @@ static void usage(void)
 		"Usage:\n");
 	printf("\tiwmon [options]\n");
 	printf("Options:\n"
-		"\t-r, --read <file>      Read netlink PCAP trace file\n"
-		"\t-w, --write <file>     Write netlink PCAP trace file\n"
-		"\t-a, --analyze <file>   Analyze netlink PCAP trace file\n"
-		"\t-i, --interface <dev>  Use specified netlink monitor\n"
-		"\t-n, --nortnl           Don't show RTNL output\n"
-		"\t-y, --nowiphy          Don't show 'New Wiphy' output\n"
-		"\t-s, --noscan           Don't show scan result output\n"
-		"\t-e, --noies            Don't show IEs except SSID\n"
-		"\t-h, --help             Show help options\n");
+		"\t-r, --read <file>          Read netlink PCAP trace file\n"
+		"\t-w, --write <file>         Write netlink PCAP trace file\n"
+		"\t-a, --analyze <file>       Analyze netlink PCAP trace file\n"
+		"\t-i, --interface <dev>      Use specified netlink monitor\n"
+		"\t-n, --nortnl               Don't show RTNL output\n"
+		"\t-y, --nowiphy              Don't show 'New Wiphy' output\n"
+		"\t-s, --noscan               Don't show scan result output\n"
+		"\t-e, --noies                Don't show IEs except SSID\n"
+		"\t-t, --time-format <format> Time format to display. Either\n"
+						"\t\t\t\t   'delta' or 'utc'.\n"
+		"\t-h, --help                 Show help options\n");
 }
 
 static const struct option main_options[] = {
-	{ "read",      required_argument, NULL, 'r' },
-	{ "write",     required_argument, NULL, 'w' },
-	{ "analyze",   required_argument, NULL, 'a' },
-	{ "nl80211",   required_argument, NULL, 'F' },
-	{ "interface", required_argument, NULL, 'i' },
-	{ "nortnl",    no_argument,       NULL, 'n' },
-	{ "nowiphy",   no_argument,       NULL, 'y' },
-	{ "noscan",    no_argument,       NULL, 's' },
-	{ "noies",     no_argument,       NULL, 'e' },
-	{ "version",   no_argument,       NULL, 'v' },
-	{ "help",      no_argument,       NULL, 'h' },
+	{ "read",        required_argument, NULL, 'r' },
+	{ "write",       required_argument, NULL, 'w' },
+	{ "analyze",     required_argument, NULL, 'a' },
+	{ "nl80211",     required_argument, NULL, 'F' },
+	{ "interface",   required_argument, NULL, 'i' },
+	{ "nortnl",      no_argument,       NULL, 'n' },
+	{ "nowiphy",     no_argument,       NULL, 'y' },
+	{ "noscan",      no_argument,       NULL, 's' },
+	{ "noies",       no_argument,       NULL, 'e' },
+	{ "time-format", required_argument, NULL, 't' },
+	{ "version",     no_argument,       NULL, 'v' },
+	{ "help",        no_argument,       NULL, 'h' },
 	{ }
 };
 
@@ -754,7 +757,7 @@ int main(int argc, char *argv[])
 	for (;;) {
 		int opt;
 
-		opt = getopt_long(argc, argv, "r:w:a:i:nvhyse",
+		opt = getopt_long(argc, argv, "r:w:a:i:t:nvhyse",
 						main_options, NULL);
 		if (opt < 0)
 			break;
@@ -784,6 +787,17 @@ int main(int argc, char *argv[])
 			break;
 		case 'e':
 			config.noies = true;
+			break;
+		case 't':
+			if (!strcmp(optarg, "delta"))
+				config.time_format = TIME_FORMAT_DELTA;
+			else if (!strcmp(optarg, "utc"))
+				config.time_format = TIME_FORMAT_UTC;
+			else {
+				printf("Invalid time format '%s'", optarg);
+				return EXIT_FAILURE;
+			}
+
 			break;
 		case 'v':
 			printf("%s\n", VERSION);
diff --git a/monitor/nlmon.c b/monitor/nlmon.c
index 60adddc5..4ecbc5f0 100644
--- a/monitor/nlmon.c
+++ b/monitor/nlmon.c
@@ -29,6 +29,7 @@
 #include <errno.h>
 #include <ctype.h>
 #include <unistd.h>
+#include <time.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>
@@ -113,6 +114,7 @@ struct nlmon {
 	bool noscan;
 	bool noies;
 	bool read;
+	enum time_format time_format;
 };
 
 struct nlmon_req {
@@ -185,11 +187,15 @@ static void nlmon_req_free(void *data)
 }
 
 static time_t time_offset = ((time_t) -1);
+static enum time_format time_format;
 
-static inline void update_time_offset(const struct timeval *tv)
+static inline void update_time_offset(const struct timeval *tv,
+					enum time_format tf)
 {
-	if (tv && time_offset == ((time_t) -1))
+	if (tv && time_offset == ((time_t) -1)) {
 		time_offset = tv->tv_sec;
+		time_format = tf;
+	}
 }
 
 #define print_indent(indent, color1, prefix, title, color2, fmt, args...) \
@@ -225,15 +231,33 @@ static void print_packet(const struct timeval *tv, char ident,
 	int n, ts_len = 0, ts_pos = 0, len = 0, pos = 0;
 
 	if (tv) {
+		struct tm *tm;
+
 		if (use_color()) {
 			n = sprintf(ts_str + ts_pos, "%s", COLOR_TIMESTAMP);
 			if (n > 0)
 				ts_pos += n;
 		}
 
-		n = sprintf(ts_str + ts_pos, " %" PRId64 ".%06" PRId64,
+		switch (time_format) {
+		case TIME_FORMAT_DELTA:
+			n = sprintf(ts_str + ts_pos, " %" PRId64 ".%06" PRId64,
 					(int64_t)tv->tv_sec - time_offset,
 					(int64_t)tv->tv_usec);
+			break;
+		case TIME_FORMAT_UTC:
+			tm = gmtime(&tv->tv_sec);
+			if (!tm) {
+				n = sprintf(ts_str + ts_pos, "%s",
+						"Time error");
+				break;
+			}
+
+			n = strftime(ts_str + ts_pos, sizeof(ts_str) - ts_pos,
+					"%b %d %H:%M:%S", tm);
+			break;
+		}
+
 		if (n > 0) {
 			ts_pos += n;
 			ts_len += n;
@@ -7497,6 +7521,7 @@ struct nlmon *nlmon_create(uint16_t id, const struct nlmon_config *config)
 	nlmon->noscan = config->noscan;
 	nlmon->noies = config->noies;
 	nlmon->read = config->read_only;
+	nlmon->time_format = config->time_format;
 
 	return nlmon;
 }
@@ -8333,7 +8358,10 @@ void nlmon_print_rtnl(struct nlmon *nlmon, const struct timeval *tv,
 	int64_t aligned_size = NLMSG_ALIGN(size);
 	const struct nlmsghdr *nlmsg;
 
-	update_time_offset(tv);
+	if (nlmon->nortnl)
+		return;
+
+	update_time_offset(tv, nlmon->time_format);
 
 	for (nlmsg = data; NLMSG_OK(nlmsg, aligned_size);
 				nlmsg = NLMSG_NEXT(nlmsg, aligned_size)) {
@@ -8371,7 +8399,7 @@ void nlmon_print_genl(struct nlmon *nlmon, const struct timeval *tv,
 {
 	const struct nlmsghdr *nlmsg;
 
-	update_time_offset(tv);
+	update_time_offset(tv, nlmon->time_format);
 
 	for (nlmsg = data; NLMSG_OK(nlmsg, size);
 				nlmsg = NLMSG_NEXT(nlmsg, size)) {
@@ -8394,7 +8422,7 @@ void nlmon_print_pae(struct nlmon *nlmon, const struct timeval *tv,
 {
 	char extra_str[16];
 
-	update_time_offset(tv);
+	update_time_offset(tv, nlmon->time_format);
 
 	sprintf(extra_str, "len %u", size);
 
diff --git a/monitor/nlmon.h b/monitor/nlmon.h
index bb1a7c58..bbc5d250 100644
--- a/monitor/nlmon.h
+++ b/monitor/nlmon.h
@@ -25,12 +25,18 @@
 
 struct nlmon;
 
+enum time_format {
+	TIME_FORMAT_DELTA,
+	TIME_FORMAT_UTC,
+};
+
 struct nlmon_config {
 	bool nortnl;
 	bool nowiphy;
 	bool noscan;
 	bool noies;
 	bool read_only;
+	enum time_format time_format;
 };
 
 struct nlmon *nlmon_open(uint16_t id, const char *pathname,
-- 
2.34.1