1 files changed, 100 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/bpf_arena_htab.h b/tools/testing/selftests/bpf/bpf_arena_htab.h
new file mode 100644
index 000000000000..acc01a876668
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_arena_htab.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#pragma once
+#include <errno.h>
+#include "bpf_arena_alloc.h"
+#include "bpf_arena_list.h"
+
+struct htab_bucket {
+	struct arena_list_head head;
+};
+typedef struct htab_bucket __arena htab_bucket_t;
+
+struct htab {
+	htab_bucket_t *buckets;
+	int n_buckets;
+};
+typedef struct htab __arena htab_t;
+
+static inline htab_bucket_t *__select_bucket(htab_t *htab, __u32 hash)
+{
+	htab_bucket_t *b = htab->buckets;
+
+	cast_kern(b);
+	return &b[hash & (htab->n_buckets - 1)];
+}
+
+static inline arena_list_head_t *select_bucket(htab_t *htab, __u32 hash)
+{
+	return &__select_bucket(htab, hash)->head;
+}
+
+struct hashtab_elem {
+	int hash;
+	int key;
+	int value;
+	struct arena_list_node hash_node;
+};
+typedef struct hashtab_elem __arena hashtab_elem_t;
+
+static hashtab_elem_t *lookup_elem_raw(arena_list_head_t *head, __u32 hash, int key)
+{
+	hashtab_elem_t *l;
+
+	list_for_each_entry(l, head, hash_node)
+		if (l->hash == hash && l->key == key)
+			return l;
+
+	return NULL;
+}
+
+static int htab_hash(int key)
+{
+	return key;
+}
+
+__weak int htab_lookup_elem(htab_t *htab __arg_arena, int key)
+{
+	hashtab_elem_t *l_old;
+	arena_list_head_t *head;
+
+	cast_kern(htab);
+	head = select_bucket(htab, key);
+	l_old = lookup_elem_raw(head, htab_hash(key), key);
+	if (l_old)
+		return l_old->value;
+	return 0;
+}
+
+__weak int htab_update_elem(htab_t *htab __arg_arena, int key, int value)
+{
+	hashtab_elem_t *l_new = NULL, *l_old;
+	arena_list_head_t *head;
+
+	cast_kern(htab);
+	head = select_bucket(htab, key);
+	l_old = lookup_elem_raw(head, htab_hash(key), key);
+
+	l_new = bpf_alloc(sizeof(*l_new));
+	if (!l_new)
+		return -ENOMEM;
+	l_new->key = key;
+	l_new->hash = htab_hash(key);
+	l_new->value = value;
+
+	list_add_head(&l_new->hash_node, head);
+	if (l_old) {
+		list_del(&l_old->hash_node);
+		bpf_free(l_old);
+	}
+	return 0;
+}
+
+void htab_init(htab_t *htab)
+{
+	void __arena *buckets = bpf_arena_alloc_pages(&arena, NULL, 2, NUMA_NO_NODE, 0);
+
+	cast_user(buckets);
+	htab->buckets = buckets;
+	htab->n_buckets = 2 * PAGE_SIZE / sizeof(struct htab_bucket);
+}