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+/*
+ * This file is free software: you may copy, redistribute and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This file 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/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+
+Copyright 2007, 2008 by Grégoire Henry, Julien Cristau and Juliusz Chroboczek
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+#include <sys/time.h>
+#include <sys/param.h>
+#include <time.h>
+
+#include "babeld.h"
+
+#include "kernel_zebra.c"
+
+/* Like gettimeofday, but returns monotonic time. If POSIX clocks are not
+ available, falls back to gettimeofday but enforces monotonicity. */
+int
+gettime(struct timeval *tv)
+{
+ int rc;
+ static time_t offset = 0, previous = 0;
+
+#if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0 && defined(CLOCK_MONOTONIC)
+ static int have_posix_clocks = -1;
+
+ if(UNLIKELY(have_posix_clocks < 0)) {
+ struct timespec ts;
+ rc = clock_gettime(CLOCK_MONOTONIC, &ts);
+ if(rc < 0) {
+ have_posix_clocks = 0;
+ } else {
+ have_posix_clocks = 1;
+ }
+ }
+
+ if(have_posix_clocks) {
+ struct timespec ts;
+ int rc;
+ rc = clock_gettime(CLOCK_MONOTONIC, &ts);
+ if(rc < 0)
+ return rc;
+ tv->tv_sec = ts.tv_sec;
+ tv->tv_usec = ts.tv_nsec / 1000;
+ return rc;
+ }
+#endif
+
+ rc = gettimeofday(tv, NULL);
+ if(rc < 0)
+ return rc;
+ tv->tv_sec += offset;
+ if(UNLIKELY(previous > tv->tv_sec)) {
+ offset += previous - tv->tv_sec;
+ tv->tv_sec = previous;
+ }
+ previous = tv->tv_sec;
+ return rc;
+}
+
+/* If /dev/urandom doesn't exist, this will fail with ENOENT, which the
+ caller will deal with gracefully. */
+
+int
+read_random_bytes(void *buf, size_t len)
+{
+ int fd;
+ int rc;
+
+ fd = open("/dev/urandom", O_RDONLY);
+ if(fd < 0) {
+ rc = -1;
+ } else {
+ rc = read(fd, buf, len);
+ if(rc < 0 || (unsigned) rc < len)
+ rc = -1;
+ close(fd);
+ }
+ return rc;
+}
+