CBQ, implement overhead parameter parsing.

For CBQ, implement overhead parameter parsing.

The change is ABI (Application Binary Interface) backward compatible
with older kernels, but will first have effect from kernel 2.6.24.
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Stephen Hemminger <stephen.hemminger@vyatta.com>

tc/q_cbq.c

@@ -53,6 +53,7 @@ static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 	struct tc_cbq_lssopt lss;
 	__u32 rtab[256];
 	unsigned mpu=0, avpkt=0, allot=0;
+	unsigned short overhead=0;
 	int cell_log=-1;
 	int ewma_log=-1;
 	struct rtattr *tail;
@@ -113,6 +114,11 @@ static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 				explain1("allot");
 				return -1;
 			}
+		} else if (matches(*argv, "overhead") == 0) {
+			NEXT_ARG();
+			if (get_u16(&overhead, *argv, 10)) {
+				explain1("overhead"); return -1;
+			}
 		} else if (matches(*argv, "help") == 0) {
 			explain();
 			return -1;
@@ -138,6 +144,7 @@ static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 		allot = (avpkt*3)/2;
 
 	r.mpu = mpu;
+	r.overhead = overhead;
 	if (tc_calc_rtable(&r, rtab, cell_log, allot) < 0) {
 		fprintf(stderr, "CBQ: failed to calculate rate table.\n");
 		return -1;
@@ -179,6 +186,7 @@ static int cbq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, str
 	int ewma_log=-1;
 	unsigned bndw = 0;
 	unsigned minburst=0, maxburst=0;
+	unsigned short overhead=0;
 	struct rtattr *tail;
 
 	memset(&r, 0, sizeof(r));
@@ -317,6 +325,11 @@ static int cbq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, str
 			if (err == 1)
 				fopt.defchange = ~0;
 			fopt_ok++;
+		} else if (matches(*argv, "overhead") == 0) {
+			NEXT_ARG();
+			if (get_u16(&overhead, *argv, 10)) {
+				explain1("overhead"); return -1;
+			}
 		} else if (matches(*argv, "help") == 0) {
 			explain_class();
 			return -1;
@@ -336,6 +349,7 @@ static int cbq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, str
 		if (wrr.allot < (lss.avpkt*3)/2)
 			wrr.allot = (lss.avpkt*3)/2;
 		r.mpu = mpu;
+		r.overhead = overhead;
 		if (tc_calc_rtable(&r, rtab, cell_log, pktsize) < 0) {
 			fprintf(stderr, "CBQ: failed to calculate rate table.\n");
 			return -1;
@@ -464,6 +478,8 @@ static int cbq_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 			fprintf(f, "cell %ub ", 1<<r->cell_log);
 			if (r->mpu)
 				fprintf(f, "mpu %ub ", r->mpu);
+			if (r->overhead)
+				fprintf(f, "overhead %ub ", r->overhead);
 		}
 	}
 	if (lss && lss->flags) {