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Date: Mon, 29 Oct 2007 00:23:07 -0700
From: Corey Hickey <bugfood-ml@...ooh.org>
To: netdev@...r.kernel.org
Cc: Corey Hickey <bugfood-ml@...ooh.org>
Subject: [PATCH 8/8] Use nested compat attributes to pass parameters.
This fixes the ambiguity between, for example:
tc qdisc change ... perturb 0
tc qdisc change ...
Without this patch, there is no way for SFQ to differentiate between
a parameter specified to be 0 and a parameter that was omitted.
Signed-off-by: Corey Hickey <bugfood-ml@...ooh.org>
---
include/linux/pkt_sched.h | 13 ++++++++
net/sched/sch_sfq.c | 69 ++++++++++++++++++++++++++++++++++----------
2 files changed, 66 insertions(+), 16 deletions(-)
diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index 14a08ad..b1a1a52 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -148,6 +148,19 @@ struct tc_sfq_qopt
unsigned flows; /* Maximal number of flows */
};
+enum
+{
+ TCA_SFQ_UNSPEC,
+ TCA_SFQ_COMPAT,
+ TCA_SFQ_QUANTUM,
+ TCA_SFQ_PERTURB,
+ TCA_SFQ_LIMIT,
+ TCA_SFQ_DIVISOR,
+ TCA_SFQ_FLOWS,
+ __TCA_SFQ_MAX,
+};
+
+#define TCA_SFQ_MAX (__TCA_SFQ_MAX - 1)
/* RED section */
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 2764a54..5c25b05 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -456,6 +456,29 @@ sfq_copy_parameters(struct sfq_sched_data *dst, struct sfq_sched_data *src)
dst->depth = src->depth;
}
+/* SFQ parameters exist as individual rtattr attributes, with a nested
+ * "struct tc_sfq_qopt" for compatibility with older userspace tools. If an
+ * individual attribute is set, we want to use it; otherwise, fall back to the
+ * nested struct.
+ * There is one caveat: if a member of the nested struct is 0, we cannot
+ * determine if that parameter is supposed to be 0 or if it is merely unset.
+ * So, only set a parameter if the corresponding struct member (u32 compat) is
+ * nonzero. When setting a parameter to 0, it is necessary to use the
+ * individual attribute. */
+static inline int
+sfq_get_parameter(u32 *dst, struct rtattr *tb[TCA_SFQ_MAX], int attr,
+ u32 compat)
+{
+ struct rtattr *rta = tb[(attr - 1)];
+ if (rta)
+ *dst = RTA_GET_U32(rta);
+ else if (compat)
+ *dst = compat;
+
+ rtattr_failure:
+ return -EINVAL;
+}
+
static int
sfq_q_init(struct sfq_sched_data *q, struct rtattr *opt)
{
@@ -465,21 +488,24 @@ sfq_q_init(struct sfq_sched_data *q, struct rtattr *opt)
* the previous values (sfq_change). So, overwrite the parameters as
* specified. */
if (opt) {
- struct tc_sfq_qopt *ctl = RTA_DATA(opt);
-
- if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
- return -EINVAL;
-
- if (ctl->quantum)
- q->quantum = ctl->quantum;
- if (ctl->perturb_period)
- q->perturb_period = ctl->perturb_period;
- if (ctl->divisor)
- q->hash_divisor = ctl->divisor;
- if (ctl->flows)
- q->depth = ctl->flows;
- if (ctl->limit)
- q->limit = ctl->limit;
+ struct tc_sfq_qopt *ctl;
+ struct rtattr *tb[TCA_SFQ_MAX];
+
+ if (rtattr_parse_nested_compat(tb, TCA_SFQ_MAX, opt, ctl,
+ sizeof(*ctl)))
+ goto rtattr_failure;
+
+ if (sfq_get_parameter(&(q->quantum), tb, TCA_SFQ_QUANTUM,
+ ctl->quantum) ||
+ sfq_get_parameter(&(q->perturb_period), tb, TCA_SFQ_PERTURB,
+ ctl->perturb_period) ||
+ sfq_get_parameter(&(q->hash_divisor), tb, TCA_SFQ_DIVISOR,
+ ctl->divisor) ||
+ sfq_get_parameter(&(q->depth), tb, TCA_SFQ_FLOWS,
+ ctl->flows) ||
+ sfq_get_parameter(&(q->limit), tb, TCA_SFQ_LIMIT,
+ ctl->limit))
+ goto rtattr_failure;
if (q->depth > SFQ_MAX_DEPTH ||
q->hash_divisor > SFQ_MAX_DIVISOR)
@@ -519,6 +545,8 @@ sfq_q_init(struct sfq_sched_data *q, struct rtattr *opt)
for (i=0; i < q->depth; i++)
sfq_link(q, i);
return 0;
+rtattr_failure:
+ return -EINVAL;
err_case:
sfq_q_destroy(q);
return -ENOBUFS;
@@ -602,17 +630,26 @@ static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct sfq_sched_data *q = qdisc_priv(sch);
unsigned char *b = skb_tail_pointer(skb);
+ struct rtattr *nest;
struct tc_sfq_qopt opt;
opt.quantum = q->quantum;
opt.perturb_period = q->perturb_period;
-
opt.limit = q->limit;
opt.divisor = q->hash_divisor;
opt.flows = q->depth;
+ nest = RTA_NEST_COMPAT(skb, TCA_OPTIONS, sizeof(opt), &opt);
+
+ RTA_PUT_U32(skb, TCA_SFQ_QUANTUM, q->quantum);
+ RTA_PUT_U32(skb, TCA_SFQ_PERTURB, q->perturb_period);
+ RTA_PUT_U32(skb, TCA_SFQ_LIMIT, q->limit);
+ RTA_PUT_U32(skb, TCA_SFQ_DIVISOR, q->hash_divisor);
+ RTA_PUT_U32(skb, TCA_SFQ_FLOWS, q->depth);
RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
+ RTA_NEST_COMPAT_END(skb, nest);
+
return skb->len;
rtattr_failure:
--
1.5.3.4
-
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