--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/bpf_verifier.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
+
+static struct bpf_struct_ops bpf_Qdisc_ops;
+
+struct bpf_sk_buff_ptr {
+ struct sk_buff *skb;
+};
+
+static int bpf_qdisc_init(struct btf *btf)
+{
+ return 0;
+}
+
+BTF_ID_LIST_SINGLE(bpf_qdisc_ids, struct, Qdisc)
+BTF_ID_LIST_SINGLE(bpf_sk_buff_ids, struct, sk_buff)
+BTF_ID_LIST_SINGLE(bpf_sk_buff_ptr_ids, struct, bpf_sk_buff_ptr)
+
+static bool bpf_qdisc_is_valid_access(int off, int size,
+ enum bpf_access_type type,
+ const struct bpf_prog *prog,
+ struct bpf_insn_access_aux *info)
+{
+ struct btf *btf = prog->aux->attach_btf;
+ u32 arg;
+
+ arg = btf_ctx_arg_idx(btf, prog->aux->attach_func_proto, off);
+ if (prog->aux->attach_st_ops_member_off == offsetof(struct Qdisc_ops, enqueue)) {
+ if (arg == 2 && type == BPF_READ) {
+ info->reg_type = PTR_TO_BTF_ID | PTR_TRUSTED;
+ info->btf = btf;
+ info->btf_id = bpf_sk_buff_ptr_ids[0];
+ return true;
+ }
+ }
+
+ return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
+}
+
+static int bpf_qdisc_qdisc_access(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, size_t *end)
+{
+ switch (off) {
+ case offsetof(struct Qdisc, limit):
+ *end = offsetofend(struct Qdisc, limit);
+ break;
+ case offsetof(struct Qdisc, q) + offsetof(struct qdisc_skb_head, qlen):
+ *end = offsetof(struct Qdisc, q) + offsetofend(struct qdisc_skb_head, qlen);
+ break;
+ case offsetof(struct Qdisc, qstats) ... offsetofend(struct Qdisc, qstats) - 1:
+ *end = offsetofend(struct Qdisc, qstats);
+ break;
+ default:
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int bpf_qdisc_sk_buff_access(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, size_t *end)
+{
+ switch (off) {
+ case offsetof(struct sk_buff, tstamp):
+ *end = offsetofend(struct sk_buff, tstamp);
+ break;
+ case offsetof(struct sk_buff, cb) + offsetof(struct qdisc_skb_cb, data[0]) ...
+ offsetof(struct sk_buff, cb) + offsetof(struct qdisc_skb_cb,
+ data[QDISC_CB_PRIV_LEN - 1]):
+ *end = offsetof(struct sk_buff, cb) +
+ offsetofend(struct qdisc_skb_cb, data[QDISC_CB_PRIV_LEN - 1]);
+ break;
+ default:
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int bpf_qdisc_btf_struct_access(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, int size)
+{
+ const struct btf_type *t, *skbt, *qdisct;
+ size_t end;
+ int err;
+
+ skbt = btf_type_by_id(reg->btf, bpf_sk_buff_ids[0]);
+ qdisct = btf_type_by_id(reg->btf, bpf_qdisc_ids[0]);
+ t = btf_type_by_id(reg->btf, reg->btf_id);
+
+ if (t == skbt) {
+ err = bpf_qdisc_sk_buff_access(log, reg, off, &end);
+ } else if (t == qdisct) {
+ err = bpf_qdisc_qdisc_access(log, reg, off, &end);
+ } else {
+ bpf_log(log, "only read is supported\n");
+ return -EACCES;
+ }
+
+ if (err) {
+ bpf_log(log, "no write support to %s at off %d\n",
+ btf_name_by_offset(reg->btf, t->name_off), off);
+ return -EACCES;
+ }
+
+ if (off + size > end) {
+ bpf_log(log,
+ "write access at off %d with size %d beyond the member of %s ended at %zu\n",
+ off, size, btf_name_by_offset(reg->btf, t->name_off), end);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static const struct bpf_verifier_ops bpf_qdisc_verifier_ops = {
+ .get_func_proto = bpf_base_func_proto,
+ .is_valid_access = bpf_qdisc_is_valid_access,
+ .btf_struct_access = bpf_qdisc_btf_struct_access,
+};
+
+static int bpf_qdisc_init_member(const struct btf_type *t,
+ const struct btf_member *member,
+ void *kdata, const void *udata)
+{
+ const struct Qdisc_ops *uqdisc_ops;
+ struct Qdisc_ops *qdisc_ops;
+ u32 moff;
+
+ uqdisc_ops = (const struct Qdisc_ops *)udata;
+ qdisc_ops = (struct Qdisc_ops *)kdata;
+
+ moff = __btf_member_bit_offset(t, member) / 8;
+ switch (moff) {
+ case offsetof(struct Qdisc_ops, peek):
+ qdisc_ops->peek = qdisc_peek_dequeued;
+ return 0;
+ case offsetof(struct Qdisc_ops, id):
+ if (bpf_obj_name_cpy(qdisc_ops->id, uqdisc_ops->id,
+ sizeof(qdisc_ops->id)) <= 0)
+ return -EINVAL;
+ return 1;
+ }
+
+ return 0;
+}
+
+static int bpf_qdisc_reg(void *kdata, struct bpf_link *link)
+{
+ return register_qdisc(kdata);
+}
+
+static void bpf_qdisc_unreg(void *kdata, struct bpf_link *link)
+{
+ return unregister_qdisc(kdata);
+}
+
+static int Qdisc_ops__enqueue(struct sk_buff *skb__ref, struct Qdisc *sch,
+ struct sk_buff **to_free)
+{
+ return 0;
+}
+
+static struct sk_buff *Qdisc_ops__dequeue(struct Qdisc *sch)
+{
+ return NULL;
+}
+
+static int Qdisc_ops__init(struct Qdisc *sch, struct nlattr *arg,
+ struct netlink_ext_ack *extack)
+{
+ return 0;
+}
+
+static void Qdisc_ops__reset(struct Qdisc *sch)
+{
+}
+
+static void Qdisc_ops__destroy(struct Qdisc *sch)
+{
+}
+
+static struct Qdisc_ops __bpf_ops_qdisc_ops = {
+ .enqueue = Qdisc_ops__enqueue,
+ .dequeue = Qdisc_ops__dequeue,
+ .init = Qdisc_ops__init,
+ .reset = Qdisc_ops__reset,
+ .destroy = Qdisc_ops__destroy,
+};
+
+static struct bpf_struct_ops bpf_Qdisc_ops = {
+ .verifier_ops = &bpf_qdisc_verifier_ops,
+ .reg = bpf_qdisc_reg,
+ .unreg = bpf_qdisc_unreg,
+ .init_member = bpf_qdisc_init_member,
+ .init = bpf_qdisc_init,
+ .name = "Qdisc_ops",
+ .cfi_stubs = &__bpf_ops_qdisc_ops,
+ .owner = THIS_MODULE,
+};
+
+static int __init bpf_qdisc_kfunc_init(void)
+{
+ return register_bpf_struct_ops(&bpf_Qdisc_ops, Qdisc_ops);
+}
+late_initcall(bpf_qdisc_kfunc_init);
projects / thirdparty / linux.git / commitdiff
