[PKT_SCHED]: GRED: Use a central table definition change procedure
Introduces a function gred_change_table_def() acting as a central
point to change the table definition.
Adds missing validations for table definition: MAX_DPs > DPs > 0
and def_DP < DPs thus fixing possible invalid memory reference
oopses. Only root could do it but having a typo crashing the
machine is a bit hard.
Adds missing locking while changing the table definition, the
operation of changing the number of DPs and removing shadowed VQs
may not be interrupted by a dequeue.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index a136955..fdc20ce 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -378,43 +378,72 @@
}
}
+static inline void gred_destroy_vq(struct gred_sched_data *q)
+{
+ kfree(q);
+}
+
+static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ struct tc_gred_sopt *sopt;
+ int i;
+
+ if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
+ return -EINVAL;
+
+ sopt = RTA_DATA(dps);
+
+ if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
+ return -EINVAL;
+
+ sch_tree_lock(sch);
+ table->DPs = sopt->DPs;
+ table->def = sopt->def_DP;
+
+ /*
+ * Every entry point to GRED is synchronized with the above code
+ * and the DP is checked against DPs, i.e. shadowed VQs can no
+ * longer be found so we can unlock right here.
+ */
+ sch_tree_unlock(sch);
+
+ if (sopt->grio) {
+ gred_enable_rio_mode(table);
+ gred_disable_wred_mode(table);
+ if (gred_wred_mode_check(sch))
+ gred_enable_wred_mode(table);
+ } else {
+ gred_disable_rio_mode(table);
+ gred_disable_wred_mode(table);
+ }
+
+ for (i = table->DPs; i < MAX_DPs; i++) {
+ if (table->tab[i]) {
+ printk(KERN_WARNING "GRED: Warning: Destroying "
+ "shadowed VQ 0x%x\n", i);
+ gred_destroy_vq(table->tab[i]);
+ table->tab[i] = NULL;
+ }
+ }
+
+ table->initd = 0;
+
+ return 0;
+}
+
static int gred_change(struct Qdisc *sch, struct rtattr *opt)
{
struct gred_sched *table = qdisc_priv(sch);
struct gred_sched_data *q;
struct tc_gred_qopt *ctl;
- struct tc_gred_sopt *sopt;
struct rtattr *tb[TCA_GRED_STAB];
- struct rtattr *tb2[TCA_GRED_DPS];
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_STAB, opt))
return -EINVAL;
- if (tb[TCA_GRED_PARMS-1] == 0 && tb[TCA_GRED_STAB-1] == 0) {
- rtattr_parse_nested(tb2, TCA_GRED_DPS, opt);
-
- if (tb2[TCA_GRED_DPS-1] == 0)
- return -EINVAL;
-
- sopt = RTA_DATA(tb2[TCA_GRED_DPS-1]);
- table->DPs=sopt->DPs;
- table->def=sopt->def_DP;
-
- if (sopt->grio) {
- gred_enable_rio_mode(table);
- gred_disable_wred_mode(table);
- if (gred_wred_mode_check(sch))
- gred_enable_wred_mode(table);
- } else {
- gred_disable_rio_mode(table);
- gred_disable_wred_mode(table);
- }
-
- table->initd=0;
- /* probably need to clear all the table DP entries as well */
- return 0;
- }
-
+ if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
+ return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
if (!table->DPs || tb[TCA_GRED_PARMS-1] == 0 || tb[TCA_GRED_STAB-1] == 0 ||
RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
@@ -526,35 +555,15 @@
static int gred_init(struct Qdisc *sch, struct rtattr *opt)
{
- struct gred_sched *table = qdisc_priv(sch);
- struct tc_gred_sopt *sopt;
- struct rtattr *tb[TCA_GRED_STAB];
- struct rtattr *tb2[TCA_GRED_DPS];
+ struct rtattr *tb[TCA_GRED_MAX];
- if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_STAB, opt))
+ if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
return -EINVAL;
- if (tb[TCA_GRED_PARMS-1] == 0 && tb[TCA_GRED_STAB-1] == 0) {
- rtattr_parse_nested(tb2, TCA_GRED_DPS, opt);
+ if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
+ return -EINVAL;
- if (tb2[TCA_GRED_DPS-1] == 0)
- return -EINVAL;
-
- sopt = RTA_DATA(tb2[TCA_GRED_DPS-1]);
- table->DPs=sopt->DPs;
- table->def=sopt->def_DP;
-
- if (sopt->grio)
- gred_enable_rio_mode(table);
- else
- gred_disable_rio_mode(table);
-
- table->initd=0;
- return 0;
- }
-
- DPRINTK("\n GRED_INIT error!\n");
- return -EINVAL;
+ return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
}
static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
@@ -641,7 +650,7 @@
for (i = 0;i < table->DPs; i++) {
if (table->tab[i])
- kfree(table->tab[i]);
+ gred_destroy_vq(table->tab[i]);
}
}
