libbpf: Support creating and destroying qdisc

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@bytedance.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409214606.2000194-8-ameryhung@gmail.com

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index e0605403f9773f868b16c7af626fa4ed5f1bab16..fdcee6a71e0fa15d701a892928f72f58e1dbdd80 100644 (file)
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1283,6 +1283,7 @@ 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)    \
@@ -1297,9 +1298,11 @@ struct bpf_tc_hook {
        int ifindex;
        enum bpf_tc_attach_point attach_point;
        __u32 parent;
+       __u32 handle;
+       const char *qdisc;
        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 68a2def171751c430054df9e0ef20e297b18ba6e..c997e69d507fef66cdc7f2c9243039a67db06a27 100644 (file)
--- 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, const struct bpf_tc_hook *hook);
 
-static int clsact_config(struct libbpf_nla_req *req)
+static int clsact_config(struct libbpf_nla_req *req, const struct bpf_tc_hook *hook)
 {
        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, const struct bpf_tc_hook *hook)
+{
+       const 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: