+
+#if NETWORKING
+/*
+ * ratecheck(): simple time-based rate-limit checking.
+ */
+int
+ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
+{
+ struct timeval tv, delta;
+ int rv = 0;
+
+ net_uptime2timeval(&tv);
+ delta = tv;
+ timevalsub(&delta, lasttime);
+
+ /*
+ * check for 0,0 is so that the message will be seen at least once,
+ * even if interval is huge.
+ */
+ if (timevalcmp(&delta, mininterval, >=) ||
+ (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
+ *lasttime = tv;
+ rv = 1;
+ }
+
+ return (rv);
+}
+
+/*
+ * ppsratecheck(): packets (or events) per second limitation.
+ */
+int
+ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
+{
+ struct timeval tv, delta;
+ int rv;
+
+ net_uptime2timeval(&tv);
+
+ timersub(&tv, lasttime, &delta);
+
+ /*
+ * Check for 0,0 so that the message will be seen at least once.
+ * If more than one second has passed since the last update of
+ * lasttime, reset the counter.
+ *
+ * we do increment *curpps even in *curpps < maxpps case, as some may
+ * try to use *curpps for stat purposes as well.
+ */
+ if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
+ delta.tv_sec >= 1) {
+ *lasttime = tv;
+ *curpps = 0;
+ rv = 1;
+ } else if (maxpps < 0)
+ rv = 1;
+ else if (*curpps < maxpps)
+ rv = 1;
+ else
+ rv = 0;
+
+#if 1 /* DIAGNOSTIC? */
+ /* be careful about wrap-around */
+ if (*curpps + 1 > 0)
+ *curpps = *curpps + 1;
+#else
+ /*
+ * assume that there's not too many calls to this function.
+ * not sure if the assumption holds, as it depends on *caller's*
+ * behavior, not the behavior of this function.
+ * IMHO it is wrong to make assumption on the caller's behavior,
+ * so the above #if is #if 1, not #ifdef DIAGNOSTIC.
+ */
+ *curpps = *curpps + 1;
+#endif
+
+ return (rv);
+}
+#endif /* NETWORKING */
+
projects / apple / xnu.git / blobdiff