bpf: net_sched: Make some Qdisc_ops ops mandatory

The patch makes all currently supported Qdisc_ops (i.e., .enqueue,
.dequeue, .init, .reset, and .destroy) mandatory.

Make .init, .reset and .destroy mandatory as bpf qdisc relies on prologue
and epilogue to check attach points and correctly initialize/cleanup
resources. The prologue/epilogue will only be generated for an struct_ops
operator only if users implement the operator.

Make .enqueue and .dequeue mandatory as bpf qdisc infra does not provide
a default data path.

Fixes: c8240344956e ("bpf: net_sched: Support implementation of Qdisc_ops in bpf")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c
index a8efc3ff2b7e469a71827993981bf2c803d03e44..7ea8b54b2ab1f7f2efb59ea850f3a246e79bd946 100644 (file)
--- a/net/sched/bpf_qdisc.c
+++ b/net/sched/bpf_qdisc.c
@@ -395,6 +395,17 @@ static void bpf_qdisc_unreg(void *kdata, struct bpf_link *link)
        return unregister_qdisc(kdata);
 }
 
+static int bpf_qdisc_validate(void *kdata)
+{
+       struct Qdisc_ops *ops = (struct Qdisc_ops *)kdata;
+
+       if (!ops->enqueue || !ops->dequeue || !ops->init ||
+           !ops->reset || !ops->destroy)
+               return -EINVAL;
+
+       return 0;
+}
+
 static int Qdisc_ops__enqueue(struct sk_buff *skb__ref, struct Qdisc *sch,
                              struct sk_buff **to_free)
 {
@@ -432,6 +443,7 @@ static struct bpf_struct_ops bpf_Qdisc_ops = {
        .verifier_ops = &bpf_qdisc_verifier_ops,
        .reg = bpf_qdisc_reg,
        .unreg = bpf_qdisc_unreg,
+       .validate = bpf_qdisc_validate,
        .init_member = bpf_qdisc_init_member,
        .init = bpf_qdisc_init,
        .name = "Qdisc_ops",