Patrick McHardy wrote:
Corey Hickey wrote:
perturb_period is currently a signed integer, but I can't see any good
reason why this is so--a negative perturbation period will add a timer
that expires in the past, causing constant perturbation, which makes
hashing useless.
if (q->perturb_period) {
q->perturb_timer.expires = jiffies + q->perturb_period;
add_timer(&q->perturb_timer);
}
Strictly speaking, this will break binary compatibility with older
versions of tc, but that ought not to be a problem because (a) there's
no valid use for a negative perturb_period, and (b) negative values
will be seen as high values (> INT_MAX), which don't work anyway.
If perturb_period is too large, (perturb_period * HZ) will overflow the
size of an unsigned int and wrap around. So, check for thet and reject
values that are too high.
Sounds reasonable.
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -74,6 +74,9 @@
typedef unsigned int sfq_index;
#define SFQ_MAX_DEPTH (UINT_MAX / 2 - 1)
+/* We don't want perturb_period * HZ to overflow an unsigned int. */
+#define SFQ_MAX_PERTURB (UINT_MAX / HZ)
jiffies are unsigned long.
Hmm. You're right. It looks like my previous patch obviated the need for
this part. I'll remove it.
-Corey
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