On 12/13/24 3:29 PM, Amery Hung wrote:
Add a watchdog timer to bpf qdisc. The watchdog can be used to schedule
the execution of qdisc through kfunc, bpf_qdisc_schedule(). It can be
useful for building traffic shaping scheduling algorithm, where the time
the next packet will be dequeued is known.
Signed-off-by: Amery Hung <amery.hung@xxxxxxxxxxxxx>
---
include/net/sch_generic.h | 4 +++
net/sched/bpf_qdisc.c | 51 ++++++++++++++++++++++++++++++++++++++-
net/sched/sch_api.c | 11 +++++++++
net/sched/sch_generic.c | 8 ++++++
4 files changed, 73 insertions(+), 1 deletion(-)
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 5d74fa7e694c..6a252b1b0680 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -1357,4 +1357,8 @@ static inline void qdisc_synchronize(const struct Qdisc *q)
msleep(1);
}
+int bpf_qdisc_init_pre_op(struct Qdisc *sch, struct nlattr *opt, struct netlink_ext_ack *extack);
+void bpf_qdisc_destroy_post_op(struct Qdisc *sch);
+void bpf_qdisc_reset_post_op(struct Qdisc *sch);
+
#endif
diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c
index 28959424eab0..7c155207fe1e 100644
--- a/net/sched/bpf_qdisc.c
+++ b/net/sched/bpf_qdisc.c
@@ -8,6 +8,10 @@
static struct bpf_struct_ops bpf_Qdisc_ops;
+struct bpf_sched_data {
+ struct qdisc_watchdog watchdog;
+};
+
struct bpf_sk_buff_ptr {
struct sk_buff *skb;
};
@@ -17,6 +21,32 @@ static int bpf_qdisc_init(struct btf *btf)
return 0;
}
+int bpf_qdisc_init_pre_op(struct Qdisc *sch, struct nlattr *opt,
+ struct netlink_ext_ack *extack)
+{
+ struct bpf_sched_data *q = qdisc_priv(sch);
+
+ qdisc_watchdog_init(&q->watchdog, sch);
+ return 0;
+}
+EXPORT_SYMBOL(bpf_qdisc_init_pre_op);
+
+void bpf_qdisc_reset_post_op(struct Qdisc *sch)
+{
+ struct bpf_sched_data *q = qdisc_priv(sch);
+
+ qdisc_watchdog_cancel(&q->watchdog);
+}
+EXPORT_SYMBOL(bpf_qdisc_reset_post_op);
+
+void bpf_qdisc_destroy_post_op(struct Qdisc *sch)
+{
+ struct bpf_sched_data *q = qdisc_priv(sch);
+
+ qdisc_watchdog_cancel(&q->watchdog);
+}
+EXPORT_SYMBOL(bpf_qdisc_destroy_post_op);
These feel like the candidates for the ".gen_prologue" and ".gen_epilogue". Then
the changes to sch_api.c is not needed.
+
static const struct bpf_func_proto *
bpf_qdisc_get_func_proto(enum bpf_func_id func_id,
const struct bpf_prog *prog)
@@ -134,12 +164,25 @@ __bpf_kfunc void bpf_qdisc_skb_drop(struct sk_buff *skb,
__qdisc_drop(skb, (struct sk_buff **)to_free_list);
}
+/* bpf_qdisc_watchdog_schedule - Schedule a qdisc to a later time using a timer.
+ * @sch: The qdisc to be scheduled.
+ * @expire: The expiry time of the timer.
+ * @delta_ns: The slack range of the timer.
+ */
+__bpf_kfunc void bpf_qdisc_watchdog_schedule(struct Qdisc *sch, u64 expire, u64 delta_ns)
+{
+ struct bpf_sched_data *q = qdisc_priv(sch);
+
+ qdisc_watchdog_schedule_range_ns(&q->watchdog, expire, delta_ns);
+}
+
__bpf_kfunc_end_defs();
#define BPF_QDISC_KFUNC_xxx \
BPF_QDISC_KFUNC(bpf_skb_get_hash, KF_TRUSTED_ARGS) \
BPF_QDISC_KFUNC(bpf_kfree_skb, KF_RELEASE) \
BPF_QDISC_KFUNC(bpf_qdisc_skb_drop, KF_RELEASE) \
+ BPF_QDISC_KFUNC(bpf_qdisc_watchdog_schedule, KF_TRUSTED_ARGS) \
BTF_KFUNCS_START(bpf_qdisc_kfunc_ids)
#define BPF_QDISC_KFUNC(name, flag) BTF_ID_FLAGS(func, name, flag)
@@ -154,9 +197,14 @@ BPF_QDISC_KFUNC_xxx
static int bpf_qdisc_kfunc_filter(const struct bpf_prog *prog, u32 kfunc_id)
{
- if (kfunc_id == bpf_qdisc_skb_drop_ids[0])
+ if (kfunc_id == bpf_qdisc_skb_drop_ids[0]) {
if (strcmp(prog->aux->attach_func_name, "enqueue"))
return -EACCES;
+ } else if (kfunc_id == bpf_qdisc_watchdog_schedule_ids[0]) {
+ if (strcmp(prog->aux->attach_func_name, "enqueue") &&
+ strcmp(prog->aux->attach_func_name, "dequeue"))
+ return -EACCES;
+ }
return 0;
}
@@ -189,6 +237,7 @@ static int bpf_qdisc_init_member(const struct btf_type *t,
case offsetof(struct Qdisc_ops, priv_size):
if (uqdisc_ops->priv_size)
return -EINVAL;
+ qdisc_ops->priv_size = sizeof(struct bpf_sched_data);
ah. ok. The priv_size case is still needed.
