dnssec, ISO time stamps writing and parsing

src/dnssec/Makefile.am

@@ -38,6 +38,8 @@ libshared_la_SOURCES = \
 	shared/pem.h \
 	shared/shared.h \
 	shared/strtonum.h \
+	shared/timestamp.c \
+	shared/timestamp.h \
 	shared/wire.h
 
 libdnssec_la_CPPFLAGS = \

src/dnssec/shared/timestamp.c

+/*  Copyright (C) 2015 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <stdbool.h>
+#include <time.h>
+
+#include "shared.h"
+
+/*
+ * POSIX strftime supports '%z', strptime doesn't.
+ */
+#define TIME_FORMAT_BASE "%Y-%m-%dT%H:%M:%S"
+#define TIME_FORMAT_WRITE TIME_FORMAT_BASE "%z"
+#define TIME_FORMAT_READ  TIME_FORMAT_BASE
+
+/*!
+ * Read time zone offset in +hhmm or -hhmm format.
+ *
+ * Format written by '%z' specifier in \ref strftime.
+ */
+static bool read_timezone(const char *buffer, int *offset)
+{
+	assert(buffer);
+
+	if (strlen(buffer) != 5) {
+		return false;
+	}
+
+	char sign;
+	unsigned hours, mins;
+	if (sscanf(buffer, "%c%2u%2u", &sign, &hours, &mins) != 3) {
+		return false;
+	}
+
+	if (sign != '+' && sign != '-') {
+		return false;
+	}
+
+	if (hours > 23 || mins > 59) {
+		return false;
+	}
+
+	*offset = (sign == '+' ? 1 : -1) * (hours * 3600 + mins * 60);
+
+	return true;
+}
+
+_public_
+bool timestamp_write(char *buffer, size_t size, time_t timestamp)
+{
+	if (!buffer) {
+		return false;
+	}
+
+	struct tm tm = { 0 };
+	if (!gmtime_r(&timestamp, &tm)) {
+		return false;
+	}
+
+	return strftime(buffer, size, TIME_FORMAT_WRITE, &tm) != 0;
+}
+
+_public_
+bool timestamp_read(const char *buffer, time_t *timestamp_ptr)
+{
+	if (!buffer || !timestamp_ptr) {
+		return false;
+	}
+
+	struct tm tm = { 0 };
+	const char *timezone = strptime(buffer, TIME_FORMAT_READ, &tm);
+	if (timezone == NULL) {
+		return false;
+	}
+
+	int gmtoff = 0;
+	if (!read_timezone(timezone, &gmtoff)) {
+		return false;
+	}
+
+	*timestamp_ptr = timegm(&tm) - gmtoff;
+
+	return true;
+}

src/dnssec/shared/timestamp.h

+/*  Copyright (C) 2015 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stdbool.h>
+#include <time.h>
+
+/*
+ * The ISO 8610 'YYYY-MM-DDThh:mm:ss+zzzz' format is used.
+ */
+
+/*!
+ * Write time stamp into a string buffer.
+ *
+ * \param buffer     Buffer to write time stamp into.
+ * \param size       Size of the output buffer.
+ * \param timestamp  Time stamp value to be written.
+ *
+ * \return Time stamp was written successfully.
+ *
+ */
+bool timestamp_write(char *buffer, size_t size, time_t timestamp);
+
+/*!
+ * Read a time stamp from a string buffer.
+ *
+ * \param[in]  buffer     Buffer to read time stamp from.
+ * \param[out] timestamp  Read time stamp value.
+ *
+ * \return Time stamp was read successfully.
+ */
+bool timestamp_read(const char *buffer, time_t *timestamp);

src/dnssec/tests/.gitignore

@@ -24,6 +24,7 @@
 /shared_bignum
 /shared_dname
 /shared_strtonum
+/shared_timestamp
 /shared_wire
 /sign
 /sign_der

src/dnssec/tests/Makefile.am

@@ -43,6 +43,7 @@ check_PROGRAMS = \
 	shared_bignum	\
 	shared_dname	\
 	shared_strtonum	\
+	shared_timestamp \
 	shared_wire	\
 	tsig
 

src/dnssec/tests/shared_timestamp.c

+/*  Copyright (C) 2015 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <string.h>
+#include <tap/basic.h>
+
+#include "timestamp.h"
+
+int main(int argc, char *argv[])
+{
+	plan_lazy();
+
+	char buffer[128] = { 0 };
+
+	ok(timestamp_write(NULL, 0, 0) == false,
+	   "timestamp_write: no buffer");
+	ok(timestamp_write(buffer, 10, 0) == false,
+	   "timestamp_write: small buffer");
+	ok(timestamp_write(buffer, sizeof(buffer), 0) &&
+	   strcmp(buffer, "1970-01-01T00:00:00+0000") == 0,
+	   "timestamp_write: epoch begin");
+	ok(timestamp_write(buffer, sizeof(buffer), 1439554225) &&
+	   strcmp(buffer, "2015-08-14T12:10:25+0000") == 0,
+	   "timestamp_write: date in past");
+	ok(timestamp_write(buffer, sizeof(buffer), 2147483646) &&
+	   strcmp(buffer, "2038-01-19T03:14:06+0000") == 0,
+	   "timestamp_write: date in future (likely)");
+
+	time_t ts = 0;
+
+	ok(timestamp_read(NULL, &ts) == false,
+	   "timestamp_read: no buffer");
+	ok(timestamp_read("", NULL) == false,
+	   "timestamp_read: no output");
+	ok(timestamp_read("", &ts) == false,
+	   "timestamp_read: empty input");
+	ok(timestamp_read("1970-01-01T00:00:00", &ts) == false,
+	   "timestamp_read: missing time zone");
+	ok(timestamp_read("1970-01-01T00:00:00+000", &ts) == false,
+	   "timestamp_read: malformed time zone");
+	ok(timestamp_read("1970-01-01T00:00:00+2400", &ts) == false,
+	   "timestamp_read: malformed time zone hours");
+	ok(timestamp_read("1970-01-01T00:00:00+0090", &ts) == false,
+	   "timestamp_read: malformed time zone minuts");
+	ok(timestamp_read("1970-01-01T00:00:01+0000", &ts) && ts == 1,
+	   "timestamp_read: first second since epoch");
+	ok(timestamp_read("2009-02-13T23:31:31+0000", &ts) && ts == 1234567891,
+	   "timestamp_read: date in past");
+	ok(timestamp_read("2034-05-05T01:24:20+0000", &ts) && ts == 2030405060,
+	   "timestamp_read: date in future (likely)");
+
+	ok(timestamp_read("2015-08-14T14:25:46+0200", &ts) &&
+	   timestamp_write(buffer, sizeof(buffer), ts) &&
+	   strcmp(buffer, "2015-08-14T12:25:46+0000") == 0,
+	   "timestamp convert time zone (east)");
+	ok(timestamp_read("2015-08-14T10:19:17-0230", &ts) &&
+	   timestamp_write(buffer, sizeof(buffer), ts) &&
+	   strcmp(buffer, "2015-08-14T12:49:17+0000") == 0,
+	   "timestamp convert time zone (west)");
+
+	return 0;
+}