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[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>
This commit is contained in:
Thomas Graf 2005-11-05 21:14:13 +01:00 committed by Thomas Graf
parent e06368221c
commit 6639607ed9
1 changed files with 62 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

115
net/sched/sch_gred.c
View File

@ -378,43 +378,72 @@ static void gred_reset(struct Qdisc* sch)
}
}
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_change(struct Qdisc *sch, struct rtattr *opt)
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 @@ static void gred_destroy(struct Qdisc *sch)
for (i = 0;i < table->DPs; i++) {
if (table->tab[i])
kfree(table->tab[i]);
gred_destroy_vq(table->tab[i]);
}
}