tc: gred: Add support for TCA_GRED_LIMIT attribute

Allow the qdisc limit to be set, which is particularly useful when
the default VQ is not configured with RED parameters.

Signed-off-by: David Ward <david.ward@ll.mit.edu>

diff --git a/tc/q_gred.c b/tc/q_gred.c
index 463d725ff0278c5df0107875b49282dd430ee2f0..f31daa37ddc975d93c7d945f6914fb33e073f308 100644 (file)
--- a/tc/q_gred.c
+++ b/tc/q_gred.c
@@ -38,7 +38,7 @@
 static void explain(void)
 {
        fprintf(stderr, "Usage: tc qdisc { add | replace | change } ... gred setup vqs NUMBER\n");
-       fprintf(stderr, "           default DEFAULT_VQ [ grio ]\n");
+       fprintf(stderr, "           default DEFAULT_VQ [ grio ] [ limit BYTES ]\n");
        fprintf(stderr, "       tc qdisc change ... gred vq VQ [ prio VALUE ] limit BYTES\n");
        fprintf(stderr, "           min BYTES max BYTES avpkt BYTES [ burst PACKETS ]\n");
        fprintf(stderr, "           [ probability PROBABILITY ] [ bandwidth KBPS ]\n");
@@ -50,6 +50,7 @@ static int init_gred(struct qdisc_util *qu, int argc, char **argv,
 
        struct rtattr *tail;
        struct tc_gred_sopt opt = { 0 };
+       __u32 limit = 0;
 
        opt.def_DP = MAX_DPs;
 
@@ -83,6 +84,12 @@ static int init_gred(struct qdisc_util *qu, int argc, char **argv,
                        }
                } else if (strcmp(*argv, "grio") == 0) {
                        opt.grio = 1;
+               } else if (strcmp(*argv, "limit") == 0) {
+                       NEXT_ARG();
+                       if (get_size(&limit, *argv)) {
+                               fprintf(stderr, "Illegal \"limit\"\n");
+                               return -1;
+                       }
                } else if (strcmp(*argv, "help") == 0) {
                        explain();
                        return -1;
@@ -104,6 +111,8 @@ static int init_gred(struct qdisc_util *qu, int argc, char **argv,
        tail = NLMSG_TAIL(n);
        addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
        addattr_l(n, 1024, TCA_GRED_DPS, &opt, sizeof(struct tc_gred_sopt));
+       if (limit)
+               addattr32(n, 1024, TCA_GRED_LIMIT, limit);
        tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
        return 0;
 }
@@ -264,6 +273,7 @@ static int gred_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
        struct tc_gred_sopt *sopt;
        struct tc_gred_qopt *qopt;
        __u32 *max_p = NULL;
+       __u32 *limit = NULL;
        unsigned i;
        SPRINT_BUF(b1);
        SPRINT_BUF(b2);
@@ -281,6 +291,10 @@ static int gred_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
            RTA_PAYLOAD(tb[TCA_GRED_MAX_P]) >= sizeof(__u32) * MAX_DPs)
                max_p = RTA_DATA(tb[TCA_GRED_MAX_P]);
 
+       if (tb[TCA_GRED_LIMIT] &&
+           RTA_PAYLOAD(tb[TCA_GRED_LIMIT]) == sizeof(__u32))
+               limit = RTA_DATA(tb[TCA_GRED_LIMIT]);
+
        sopt = RTA_DATA(tb[TCA_GRED_DPS]);
        qopt = RTA_DATA(tb[TCA_GRED_PARMS]);
        if (RTA_PAYLOAD(tb[TCA_GRED_DPS]) < sizeof(*sopt) ||
@@ -296,6 +310,10 @@ static int gred_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
                sopt->def_DP,
                sopt->grio ? "grio " : "");
 
+       if (limit)
+               fprintf(f, "limit %s ",
+                       sprint_size(*limit, b1));
+
        for (i=0;i<MAX_DPs;i++, qopt++) {
                if (qopt->DP >= MAX_DPs) continue;
                fprintf(f, "\n vq %u prio %hhu limit %s min %s max %s ",