You are right. I will add const to the hook argument and bpf_tc_hook->qdisc.
Thanks,
Amery
On Tue, Dec 17, 2024 at 10:32 AM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Fri, Dec 13, 2024 at 3:30 PM Amery Hung <amery.hung@xxxxxxxxxxxxx> wrote:
> >
> > Extend struct bpf_tc_hook with handle, qdisc name and a new attach type,
> > BPF_TC_QDISC, to allow users to add or remove any qdisc specified in
> > addition to clsact.
> >
> > Signed-off-by: Amery Hung <amery.hung@xxxxxxxxxxxxx>
> > ---
> > tools/lib/bpf/libbpf.h | 5 ++++-
> > tools/lib/bpf/netlink.c | 20 +++++++++++++++++---
> > 2 files changed, 21 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> > index b2ce3a72b11d..b05d95814776 100644
> > --- a/tools/lib/bpf/libbpf.h
> > +++ b/tools/lib/bpf/libbpf.h
> > @@ -1268,6 +1268,7 @@ enum bpf_tc_attach_point {
> > BPF_TC_INGRESS = 1 << 0,
> > BPF_TC_EGRESS = 1 << 1,
> > BPF_TC_CUSTOM = 1 << 2,
> > + BPF_TC_QDISC = 1 << 3,
> > };
> >
> > #define BPF_TC_PARENT(a, b) \
> > @@ -1282,9 +1283,11 @@ struct bpf_tc_hook {
> > int ifindex;
> > enum bpf_tc_attach_point attach_point;
> > __u32 parent;
> > + __u32 handle;
> > + char *qdisc;
>
> const char *?
>
> > size_t :0;
> > };
> > -#define bpf_tc_hook__last_field parent
> > +#define bpf_tc_hook__last_field qdisc
> >
> > struct bpf_tc_opts {
> > size_t sz;
> > diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
> > index 68a2def17175..72db8c0add21 100644
> > --- a/tools/lib/bpf/netlink.c
> > +++ b/tools/lib/bpf/netlink.c
> > @@ -529,9 +529,9 @@ int bpf_xdp_query_id(int ifindex, int flags, __u32 *prog_id)
> > }
> >
> >
> > -typedef int (*qdisc_config_t)(struct libbpf_nla_req *req);
> > +typedef int (*qdisc_config_t)(struct libbpf_nla_req *req, struct bpf_tc_hook *hook);
>
> should hook pointer be const?
>
> >
> > -static int clsact_config(struct libbpf_nla_req *req)
> > +static int clsact_config(struct libbpf_nla_req *req, struct bpf_tc_hook *hook)
>
> const?
>
> > {
> > req->tc.tcm_parent = TC_H_CLSACT;
> > req->tc.tcm_handle = TC_H_MAKE(TC_H_CLSACT, 0);
> > @@ -539,6 +539,16 @@ static int clsact_config(struct libbpf_nla_req *req)
> > return nlattr_add(req, TCA_KIND, "clsact", sizeof("clsact"));
> > }
> >
> > +static int qdisc_config(struct libbpf_nla_req *req, struct bpf_tc_hook *hook)
>
> same, const, it's not written into, right?
>
> > +{
> > + char *qdisc = OPTS_GET(hook, qdisc, NULL);
> > +
> > + req->tc.tcm_parent = OPTS_GET(hook, parent, TC_H_ROOT);
> > + req->tc.tcm_handle = OPTS_GET(hook, handle, 0);
> > +
> > + return nlattr_add(req, TCA_KIND, qdisc, strlen(qdisc) + 1);
> > +}
> > +
> > static int attach_point_to_config(struct bpf_tc_hook *hook,
> > qdisc_config_t *config)
> > {
> > @@ -552,6 +562,9 @@ static int attach_point_to_config(struct bpf_tc_hook *hook,
> > return 0;
> > case BPF_TC_CUSTOM:
> > return -EOPNOTSUPP;
> > + case BPF_TC_QDISC:
> > + *config = &qdisc_config;
> > + return 0;
> > default:
> > return -EINVAL;
> > }
> > @@ -596,7 +609,7 @@ static int tc_qdisc_modify(struct bpf_tc_hook *hook, int cmd, int flags)
> > req.tc.tcm_family = AF_UNSPEC;
> > req.tc.tcm_ifindex = OPTS_GET(hook, ifindex, 0);
> >
> > - ret = config(&req);
> > + ret = config(&req, hook);
> > if (ret < 0)
> > return ret;
> >
> > @@ -639,6 +652,7 @@ int bpf_tc_hook_destroy(struct bpf_tc_hook *hook)
> > case BPF_TC_INGRESS:
> > case BPF_TC_EGRESS:
> > return libbpf_err(__bpf_tc_detach(hook, NULL, true));
> > + case BPF_TC_QDISC:
> > case BPF_TC_INGRESS | BPF_TC_EGRESS:
> > return libbpf_err(tc_qdisc_delete(hook));
> > case BPF_TC_CUSTOM:
> > --
> > 2.20.1
> >
