commit 1070205dc042825dddcc30b478173f85c6b6a509
author Vijay Subramanian <subramanian.vijay@gmail.com> Wed May 16 13:51:58 2012 +0000
committer Stephen Hemminger <shemminger@vyatta.com> Tue May 22 14:10:21 2012 -0700
tree c44cbd2df6bc34f490ae287fb70c6525b43d6521
parent 82613f9252b19041c38024f3910552c3fe411188

tc-netem: Add support for ECN packet marking

This patch provides support for marking packets with ECN instead of
dropping them with netem. This makes it possible to make use of the
netem ECN marking feature that was added recently to the kernel.

Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>

tc/q_netem.c

diff --git a/tc/q_netem.c b/tc/q_netem.c
index 360080c..f8489e9 100644
--- a/tc/q_netem.c
+++ b/tc/q_netem.c
@@ -38,6 +38,7 @@
 "                 [ 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 @@
 					*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 @@
 		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 @@
 	    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 @@
 	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 @@
 				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 @@
 			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;
 }