1 files changed, 63 insertions, 0 deletions
diff --git a/src/network/tc/tc-util.c b/src/network/tc/tc-util.c
new file mode 100644
index 0000000000..7e1cf53e11
--- /dev/null
+++ b/src/network/tc/tc-util.c
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: LGPL-2.1+
+ * Copyright © 2019 VMware, Inc. */
+
+#include "alloc-util.h"
+#include "fileio.h"
+#include "parse-util.h"
+#include "tc-util.h"
+#include "time-util.h"
+
+static int tc_init(double *ticks_in_usec) {
+        uint32_t clock_resolution, ticks_to_usec, usec_to_ticks;
+        _cleanup_free_ char *line = NULL;
+        double clock_factor;
+        int r;
+
+        r = read_one_line_file("/proc/net/psched", &line);
+        if (r < 0)
+                return r;
+
+        r = sscanf(line, "%08x%08x%08x", &ticks_to_usec, &usec_to_ticks, &clock_resolution);
+        if (r < 3)
+                return -EIO;
+
+        clock_factor =  (double) clock_resolution / USEC_PER_SEC;
+        *ticks_in_usec = (double) ticks_to_usec / usec_to_ticks * clock_factor;
+
+        return 0;
+}
+
+int tc_time_to_tick(usec_t t, uint32_t *ret) {
+        static double ticks_in_usec = -1;
+        usec_t a;
+        int r;
+
+        assert(ret);
+
+        if (ticks_in_usec < 0) {
+                r = tc_init(&ticks_in_usec);
+                if (r < 0)
+                        return r;
+        }
+
+        a = t * ticks_in_usec;
+        if (a > UINT32_MAX)
+                return -ERANGE;
+
+        *ret = a;
+        return 0;
+}
+
+int parse_tc_percent(const char *s, uint32_t *percent)  {
+        int r;
+
+        assert(s);
+        assert(percent);
+
+        r = parse_permille(s);
+        if (r < 0)
+                return r;
+
+        *percent = (double) r / 1000 * UINT32_MAX;
+        return 0;
+}