red: make burst optional

Documentation advises to set burst to (min+min+max)/(3*avpkt)

Let tc do this automatically if user doesnt provide burst himself.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

tc/q_choke.c

@@ -133,7 +133,7 @@ static int choke_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 		return -1;
 	}
 	if (wlog >= 10)
-		fprintf(stderr, "CHOKE: WARNING. Burst %d seems to be to large.\n", burst);
+		fprintf(stderr, "CHOKE: WARNING. Burst %d seems to be too large.\n", burst);
 	opt.Wlog = wlog;
 
 	wlog = tc_red_eval_P(opt.qth_min*avpkt, opt.qth_max*avpkt, probability);

tc/q_gred.c

@@ -215,19 +215,23 @@ static int gred_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct n
 	if (rate == 0)
 		get_rate(&rate, "10Mbit");
 
-	if (!opt.qth_min || !opt.qth_max || !burst || !opt.limit || !avpkt ||
+	if (!opt.qth_min || !opt.qth_max || !opt.limit || !avpkt ||
 	    (opt.DP<0)) {
-		fprintf(stderr, "Required parameter (min, max, burst, limit, "
+		fprintf(stderr, "Required parameter (min, max, limit, "
 		    "avpkt, DP) is missing\n");
 		return -1;
 	}
+	if (!burst) {
+		burst = (2 * opt.qth_min + opt.qth_max) / (3 * avpkt);
+		fprintf(stderr, "GRED: set burst to %u\n", burst);
+	}
 
 	if ((wlog = tc_red_eval_ewma(opt.qth_min, burst, avpkt)) < 0) {
 		fprintf(stderr, "GRED: failed to calculate EWMA constant.\n");
 		return -1;
 	}
 	if (wlog >= 10)
-		fprintf(stderr, "GRED: WARNING. Burst %d seems to be to "
+		fprintf(stderr, "GRED: WARNING. Burst %d seems to be too "
 		    "large.\n", burst);
 	opt.Wlog = wlog;
 	if ((wlog = tc_red_eval_P(opt.qth_min, opt.qth_max, probability)) < 0) {

tc/q_red.c

@@ -104,17 +104,20 @@ static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 	if (rate == 0)
 		get_rate(&rate, "10Mbit");
 
-	if (!opt.qth_min || !opt.qth_max || !burst || !opt.limit || !avpkt) {
-		fprintf(stderr, "Required parameter (min, max, burst, limit, avpkt) is missing\n");
+	if (!opt.qth_min || !opt.qth_max || !opt.limit || !avpkt) {
+		fprintf(stderr, "RED: Required parameter (min, max, limit, avpkt) is missing\n");
 		return -1;
 	}
-
+	if (!burst) {
+		burst = (2 * opt.qth_min + opt.qth_max) / (3 * avpkt);
+		fprintf(stderr, "RED: set burst to %u\n", burst);
+	}
 	if ((wlog = tc_red_eval_ewma(opt.qth_min, burst, avpkt)) < 0) {
 		fprintf(stderr, "RED: failed to calculate EWMA constant.\n");
 		return -1;
 	}
 	if (wlog >= 10)
-		fprintf(stderr, "RED: WARNING. Burst %d seems to be to large.\n", burst);
+		fprintf(stderr, "RED: WARNING. Burst %d seems to be too large.\n", burst);
 	opt.Wlog = wlog;
 	if ((wlog = tc_red_eval_P(opt.qth_min, opt.qth_max, probability)) < 0) {
 		fprintf(stderr, "RED: failed to calculate probability.\n");