[IPROUTE2 0/2] Add ECN support to tc-netem

@@ -30,8 +30,8 @@ NetEm \- Network Emulator
 .IR p13 " [ " p31 " [ " p32 " [ " p23 " [ " p14 "]]]] |"
 .br
 .RB "               " gemodel
-.IR p " [ " r " [ " 1-h " [ " 1-k " ]]]"
-.BR " }"
+.IR p " [ " r " [ " 1-h " [ " 1-k " ]]] } "
+.RB  " [ " ecn " ] "
 
 .IR CORRUPT " := "
 .B corrupt

@@ -102,6 +102,10 @@ model. As known, p and r are the transition probabilities between the bad and
 the good states, 1-h is the loss probability in the bad state and 1-k is the
 loss probability in the good state.
 
+.SS ecn
+can be used optionally to mark packets instead of dropping them. A loss model
+has to be used for this to be enabled.
+
 .SS corrupt
 allows the emulation of random noise introducing an error in a random position
 for a chosen percent of packets. It is also possible to add a correlation

@@ -509,6 +509,7 @@ enum {
 	TCA_NETEM_CORRUPT,
 	TCA_NETEM_LOSS,
 	TCA_NETEM_RATE,
+	TCA_NETEM_ECN,
 	__TCA_NETEM_MAX,
 };
 

@@ -38,6 +38,7 @@ static void explain(void)
 "                 [ loss random PERCENT [CORRELATION]]\n" \
 "                 [ loss state P13 [P31 [P32 [P23 P14]]]\n" \
 "                 [ loss gemodel PERCENT [R [1-H [1-K]]]\n" \
+"                 [ ecn ]\n" \
 "                 [ reorder PRECENT [CORRELATION] [ gap DISTANCE ]]\n" \
 "                 [ rate RATE [PACKETOVERHEAD] [CELLSIZE] [CELLOVERHEAD]]\n");
 }

@@ -326,6 +327,8 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 					*argv);
 				return -1;
 			}
+		} else if (matches(*argv, "ecn") == 0) {
+				present[TCA_NETEM_ECN] = 1;
 		} else if (matches(*argv, "reorder") == 0) {
 			NEXT_ARG();
 			present[TCA_NETEM_REORDER] = 1;

@@ -437,6 +440,14 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 		return -1;
 	}
 
+	if (present[TCA_NETEM_ECN]) {
+		if (opt.loss <= 0 && loss_type == NETEM_LOSS_UNSPEC) {
+			fprintf(stderr, "ecn requested without loss model\n");
+			explain();
+			return -1;
+		}
+	}
+
 	if (dist_data && (opt.latency == 0 || opt.jitter == 0)) {
 		fprintf(stderr, "distribution specified but no latency and jitter values\n");
 		explain();

@@ -454,6 +465,11 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 	    addattr_l(n, 1024, TCA_NETEM_REORDER, &reorder, sizeof(reorder)) < 0)
 		return -1;
 
+	if (present[TCA_NETEM_ECN] &&
+	    addattr_l(n, 1024, TCA_NETEM_ECN, &present[TCA_NETEM_ECN],
+		      sizeof(present[TCA_NETEM_ECN])) < 0)
+			return -1;
+
 	if (present[TCA_NETEM_CORRUPT] &&
 	    addattr_l(n, 1024, TCA_NETEM_CORRUPT, &corrupt, sizeof(corrupt)) < 0)
 		return -1;

@@ -500,6 +516,7 @@ static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 	const struct tc_netem_corrupt *corrupt = NULL;
 	const struct tc_netem_gimodel *gimodel = NULL;
 	const struct tc_netem_gemodel *gemodel = NULL;
+	int *ecn = NULL;
 	struct tc_netem_qopt qopt;
 	const struct tc_netem_rate *rate = NULL;
 	int len = RTA_PAYLOAD(opt) - sizeof(qopt);

@@ -548,6 +565,11 @@ static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 				return -1;
 			rate = RTA_DATA(tb[TCA_NETEM_RATE]);
 		}
+		if (tb[TCA_NETEM_ECN]) {
+			if (RTA_PAYLOAD(tb[TCA_NETEM_ECN]) < sizeof(*ecn))
+				return -1;
+			ecn = RTA_DATA(tb[TCA_NETEM_ECN]);
+		}
 	}
 
 	fprintf(f, "limit %d", qopt.limit);

@@ -617,9 +639,13 @@ static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 			fprintf(f, " celloverhead %d", rate->cell_overhead);
 	}
 
+	if (ecn)
+		fprintf(f, " ecn ");
+
 	if (qopt.gap)
 		fprintf(f, " gap %lu", (unsigned long)qopt.gap);
 
+
 	return 0;
 }