1 files changed, 83 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/type_cast.c b/tools/testing/selftests/bpf/progs/type_cast.c
new file mode 100644
index 000000000000..eb78e6f03129
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/type_cast.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} enter_id SEC(".maps");
+
+#define	IFNAMSIZ 16
+
+int ifindex, ingress_ifindex;
+char name[IFNAMSIZ];
+unsigned int inum;
+unsigned int meta_len, frag0_len, kskb_len, kskb2_len;
+
+void *bpf_cast_to_kern_ctx(void *) __ksym;
+void *bpf_rdonly_cast(void *, __u32) __ksym;
+
+SEC("?xdp")
+int md_xdp(struct xdp_md *ctx)
+{
+	struct xdp_buff *kctx = bpf_cast_to_kern_ctx(ctx);
+	struct net_device *dev;
+
+	dev = kctx->rxq->dev;
+	ifindex = dev->ifindex;
+	inum = dev->nd_net.net->ns.inum;
+	__builtin_memcpy(name, dev->name, IFNAMSIZ);
+	ingress_ifindex = ctx->ingress_ifindex;
+	return XDP_PASS;
+}
+
+SEC("?tc")
+int md_skb(struct __sk_buff *skb)
+{
+	struct sk_buff *kskb = bpf_cast_to_kern_ctx(skb);
+	struct skb_shared_info *shared_info;
+	struct sk_buff *kskb2;
+
+	kskb_len = kskb->len;
+
+	/* Simulate the following kernel macro:
+	 *   #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
+	 */
+	shared_info = bpf_rdonly_cast(kskb->head + kskb->end,
+		bpf_core_type_id_kernel(struct skb_shared_info));
+	meta_len = shared_info->meta_len;
+	frag0_len = shared_info->frag_list->len;
+
+	/* kskb2 should be equal to kskb */
+	kskb2 = bpf_rdonly_cast(kskb, bpf_core_type_id_kernel(struct sk_buff));
+	kskb2_len = kskb2->len;
+	return 0;
+}
+
+SEC("?tp_btf/sys_enter")
+int BPF_PROG(untrusted_ptr, struct pt_regs *regs, long id)
+{
+	struct task_struct *task, *task_dup;
+	long *ptr;
+
+	task = bpf_get_current_task_btf();
+	task_dup = bpf_rdonly_cast(task, bpf_core_type_id_kernel(struct task_struct));
+	(void)bpf_task_storage_get(&enter_id, task_dup, 0, 0);
+	return 0;
+}
+
+SEC("?tracepoint/syscalls/sys_enter_nanosleep")
+int kctx_u64(void *ctx)
+{
+	u64 *kctx = bpf_rdonly_cast(ctx, bpf_core_type_id_kernel(u64));
+
+	(void)kctx;
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";