[Patch bpf-next v4 0/3] bpf: introduce timeout hash map

[Patch bpf-next v4 0/3] bpf: introduce timeout hash map

[Cong Wang]

From: Cong Wang <cong.wang@bytedance.com>

This patchset introduces a new eBPF hash map whose elements have
timeouts. Patch 1 is the implementation of timeout map, patch 2 adds
some test cases for timeout map in test_maps, and patch 3 adds a test
case in map ptr test.

Please check each patch description for more details.

---
v4: merge gc_work into gc_idle_work to avoid a nasty race condition
    fix a potential use-after-free
    add one more test case
    improve comments and update changelog

v3: move gc list from bucket to elem
    reuse lru_node in struct htab_elem
    drop patches which are no longer necessary
    fix delete path
    add a test case for delete path
    add parallel test cases
    change timeout to ms
    drop batch ops

v2: fix hashmap ptr test
    add a test case in map ptr test
    factor out htab_timeout_map_alloc()

Cong Wang (3):
  bpf: introduce timeout hash map
  selftests/bpf: add test cases for bpf timeout map
  selftests/bpf: add timeout map check in map_ptr tests

 include/linux/bpf_types.h                     |   1 +
 include/uapi/linux/bpf.h                      |   5 +-
 kernel/bpf/hashtab.c                          | 239 +++++++++++++++++-
 kernel/bpf/syscall.c                          |   3 +-
 tools/include/uapi/linux/bpf.h                |   1 +
 .../selftests/bpf/progs/map_ptr_kern.c        |  20 ++
 tools/testing/selftests/bpf/test_maps.c       |  47 ++++
 7 files changed, 307 insertions(+), 9 deletions(-)

-- 
2.25.1

[Patch bpf-next v4 1/3] bpf: introduce timeout hash map

[Cong Wang]

From: Cong Wang <cong.wang@bytedance.com>

This borrows the idea from conntrack and will be used for conntrack in
ebpf too. Each element in a timeout map has a user-specified timeout
in msecs, after it expires it will be automatically removed from the
map. Cilium already does the same thing, it uses a regular map or LRU
map to track connections and has its own GC in user-space. This does
not scale well when we have millions of connections, as each removal
needs a syscall. Even if we could batch the operations, it still needs
to copy a lot of data between kernel and user space.

There are two cases to consider here:

1. When the timeout map is idle, i.e. no one updates or accesses it,
   we rely on the delayed work to scan the whole hash table and remove
   these expired. The delayed work is scheduled every 1 sec when idle,
   which is also what conntrack uses. It is fine to scan the whole
   table as we do not actually remove elements during this scan,
   instead we simply queue them to the lockless list and defer all the
   removals to the next schedule.

2. When the timeout map is actively accessed, we could reach expired
   elements before the idle work automatically scans them, we can
   simply skip them and schedule the delayed work immediately to do
   the actual removals. We have to avoid taking locks on fast path.

The timeout of an element can be set or updated via bpf_map_update_elem()
and we reuse the upper 32-bit of the 64-bit flag for the timeout value,
as there are only a few bits are used currently. Note, a zero timeout
means to expire immediately.

To avoid adding memory overhead to regular map, we have to reuse some
field in struct htab_elem, that is, lru_node. Otherwise we would have
to rewrite a lot of code.

For now, batch ops is not supported, we can add it later if needed.

Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dongdong Wang <wangdongdong.6@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 include/linux/bpf_types.h      |   1 +
 include/uapi/linux/bpf.h       |   5 +-
 kernel/bpf/hashtab.c           | 239 ++++++++++++++++++++++++++++++++-
 kernel/bpf/syscall.c           |   3 +-
 tools/include/uapi/linux/bpf.h |   1 +
 5 files changed, 240 insertions(+), 9 deletions(-)

diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 99f7fd657d87..00a3b17b6af2 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -125,6 +125,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops)
 #endif
 BPF_MAP_TYPE(BPF_MAP_TYPE_RINGBUF, ringbuf_map_ops)
+BPF_MAP_TYPE(BPF_MAP_TYPE_TIMEOUT_HASH, htab_timeout_map_ops)
 
 BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint)
 BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c001766adcbc..9c9d8c194b39 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -164,6 +164,7 @@ enum bpf_map_type {
 	BPF_MAP_TYPE_RINGBUF,
 	BPF_MAP_TYPE_INODE_STORAGE,
 	BPF_MAP_TYPE_TASK_STORAGE,
+	BPF_MAP_TYPE_TIMEOUT_HASH,
 };
 
 /* Note that tracing related programs such as
@@ -399,7 +400,9 @@ enum bpf_link_type {
  */
 #define BPF_PSEUDO_CALL		1
 
-/* flags for BPF_MAP_UPDATE_ELEM command */
+/* flags for BPF_MAP_UPDATE_ELEM command, upper 32 bits are timeout for
+ * BPF_MAP_TYPE_TIMEOUT_HASH (in milliseconds).
+ */
 enum {
 	BPF_ANY		= 0, /* create new element or update existing */
 	BPF_NOEXIST	= 1, /* create new element if it didn't exist */
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index c1ac7f964bc9..1347d782eb1d 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -8,6 +8,8 @@
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
 #include <linux/random.h>
+#include <linux/llist.h>
+#include <linux/workqueue.h>
 #include <uapi/linux/btf.h>
 #include <linux/rcupdate_trace.h>
 #include "percpu_freelist.h"
@@ -104,6 +106,8 @@ struct bpf_htab {
 	u32 hashrnd;
 	struct lock_class_key lockdep_key;
 	int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
+	struct llist_head gc_list;
+	struct delayed_work gc_work;
 };
 
 /* each htab element is struct htab_elem + key + value */
@@ -122,6 +126,11 @@ struct htab_elem {
 	union {
 		struct rcu_head rcu;
 		struct bpf_lru_node lru_node;
+		struct {
+			u64 expires; /* in jiffies64 */
+			struct llist_node gc_node;
+			atomic_t pending;
+		};
 	};
 	u32 hash;
 	char key[] __aligned(8);
@@ -429,6 +438,31 @@ static int htab_map_alloc_check(union bpf_attr *attr)
 	return 0;
 }
 
+static bool htab_elem_expired(struct htab_elem *e)
+{
+	return time_after_eq64(get_jiffies_64(), e->expires);
+}
+
+/* Schedule GC to remove an expired element, unless it is already pending. */
+static void htab_gc_elem(struct bpf_htab *htab, struct htab_elem *e)
+{
+	if (atomic_xchg(&e->pending, 1))
+		return;
+	llist_add(&e->gc_node, &htab->gc_list);
+	queue_delayed_work(system_unbound_wq, &htab->gc_work, 0);
+}
+
+/* GC an element if it has been expired, return whether the element is expired
+ * or not.
+ */
+static bool htab_expire_elem(struct bpf_htab *htab, struct htab_elem *e)
+{
+	if (!htab_elem_expired(e))
+		return false;
+	htab_gc_elem(htab, e);
+	return true;
+}
+
 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 {
 	bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
@@ -730,6 +764,7 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
 {
 	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	bool is_timeout = map->map_type == BPF_MAP_TYPE_TIMEOUT_HASH;
 	struct hlist_nulls_head *head;
 	struct htab_elem *l, *next_l;
 	u32 hash, key_size;
@@ -757,6 +792,8 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
 				  struct htab_elem, hash_node);
 
 	if (next_l) {
+		if (is_timeout && htab_expire_elem(htab, next_l))
+			goto find_first_elem;
 		/* if next elem in this hash list is non-zero, just return it */
 		memcpy(next_key, next_l->key, key_size);
 		return 0;
@@ -775,6 +812,8 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
 		next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
 					  struct htab_elem, hash_node);
 		if (next_l) {
+			if (is_timeout && htab_expire_elem(htab, next_l))
+				continue;
 			/* if it's not empty, just return it */
 			memcpy(next_key, next_l->key, key_size);
 			return 0;
@@ -877,6 +916,7 @@ static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 					 void *value, u32 key_size, u32 hash,
 					 bool percpu, bool onallcpus,
+					 bool timeout_map,
 					 struct htab_elem *old_elem)
 {
 	u32 size = htab->map.value_size;
@@ -952,6 +992,8 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 			       value);
 	}
 
+	if (timeout_map)
+		atomic_set(&l_new->pending, 0);
 	l_new->hash = hash;
 	return l_new;
 dec_count:
@@ -973,18 +1015,37 @@ static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
 	return 0;
 }
 
+static u64 msecs_to_expire(u32 ms)
+{
+	u64 tmp = ms * NSEC_PER_MSEC;
+
+	return nsecs_to_jiffies64(tmp) + get_jiffies_64();
+}
+
+static u32 fetch_timeout(u64 *map_flags)
+{
+	u32 timeout = (*map_flags) >> 32;
+
+	*map_flags = (*map_flags) & 0xffffffff;
+	return timeout;
+}
+
 /* Called from syscall or from eBPF program */
 static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
 				u64 map_flags)
 {
 	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	bool timeout_map = map->map_type == BPF_MAP_TYPE_TIMEOUT_HASH;
 	struct htab_elem *l_new = NULL, *l_old;
 	struct hlist_nulls_head *head;
 	unsigned long flags;
 	struct bucket *b;
 	u32 key_size, hash;
+	u32 timeout;
 	int ret;
 
+	timeout = fetch_timeout(&map_flags);
+
 	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
 		/* unknown flags */
 		return -EINVAL;
@@ -1012,6 +1073,8 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
 			copy_map_value_locked(map,
 					      l_old->key + round_up(key_size, 8),
 					      value, false);
+			if (timeout_map)
+				l_old->expires = msecs_to_expire(timeout);
 			return 0;
 		}
 		/* fall through, grab the bucket lock and lookup again.
@@ -1040,26 +1103,35 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
 		copy_map_value_locked(map,
 				      l_old->key + round_up(key_size, 8),
 				      value, false);
+		if (timeout_map)
+			l_old->expires = msecs_to_expire(timeout);
 		ret = 0;
 		goto err;
 	}
 
 	l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
-				l_old);
+				timeout_map, l_old);
 	if (IS_ERR(l_new)) {
 		/* all pre-allocated elements are in use or memory exhausted */
 		ret = PTR_ERR(l_new);
 		goto err;
 	}
 
+	if (timeout_map)
+		l_new->expires = msecs_to_expire(timeout);
+
 	/* add new element to the head of the list, so that
 	 * concurrent search will find it before old elem
 	 */
 	hlist_nulls_add_head_rcu(&l_new->hash_node, head);
 	if (l_old) {
-		hlist_nulls_del_rcu(&l_old->hash_node);
-		if (!htab_is_prealloc(htab))
-			free_htab_elem(htab, l_old);
+		if (timeout_map) {
+			htab_gc_elem(htab, l_old);
+		} else {
+			hlist_nulls_del_rcu(&l_old->hash_node);
+			if (!htab_is_prealloc(htab))
+				free_htab_elem(htab, l_old);
+		}
 	}
 	ret = 0;
 err:
@@ -1173,7 +1245,7 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
 				value, onallcpus);
 	} else {
 		l_new = alloc_htab_elem(htab, key, value, key_size,
-					hash, true, onallcpus, NULL);
+					hash, true, onallcpus, false, NULL);
 		if (IS_ERR(l_new)) {
 			ret = PTR_ERR(l_new);
 			goto err;
@@ -1269,6 +1341,7 @@ static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
 static int htab_map_delete_elem(struct bpf_map *map, void *key)
 {
 	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	bool is_timeout = map->map_type == BPF_MAP_TYPE_TIMEOUT_HASH;
 	struct hlist_nulls_head *head;
 	struct bucket *b;
 	struct htab_elem *l;
@@ -1291,8 +1364,14 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
 	l = lookup_elem_raw(head, hash, key, key_size);
 
 	if (l) {
-		hlist_nulls_del_rcu(&l->hash_node);
-		free_htab_elem(htab, l);
+		if (is_timeout) {
+			if (htab_elem_expired(l))
+				ret = -ENOENT;
+			htab_gc_elem(htab, l);
+		} else {
+			hlist_nulls_del_rcu(&l->hash_node);
+			free_htab_elem(htab, l);
+		}
 	} else {
 		ret = -ENOENT;
 	}
@@ -2178,3 +2257,149 @@ const struct bpf_map_ops htab_of_maps_map_ops = {
 	.map_btf_name = "bpf_htab",
 	.map_btf_id = &htab_of_maps_map_btf_id,
 };
+
+#define HTAB_GC_INTERVAL HZ
+
+static void htab_gc(struct work_struct *work)
+{
+	struct htab_elem *e, *tmp;
+	struct llist_node *lhead;
+	struct bpf_htab *htab;
+	int i, count;
+
+	htab = container_of(work, struct bpf_htab, gc_work.work);
+	lhead = llist_del_all(&htab->gc_list);
+
+	llist_for_each_entry_safe(e, tmp, lhead, gc_node) {
+		unsigned long flags;
+		struct bucket *b;
+		u32 hash;
+
+		hash = e->hash;
+		b = __select_bucket(htab, hash);
+		if (htab_lock_bucket(htab, b, hash, &flags))
+			continue;
+		hlist_nulls_del_rcu(&e->hash_node);
+		atomic_set(&e->pending, 0);
+		free_htab_elem(htab, e);
+		htab_unlock_bucket(htab, b, hash, flags);
+
+		cond_resched();
+	}
+
+	for (count = 0, i = 0; i < htab->n_buckets; i++) {
+		struct hlist_nulls_head *head;
+		struct hlist_nulls_node *n;
+		struct htab_elem *l;
+
+		rcu_read_lock();
+		head = select_bucket(htab, i);
+		hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+			if (htab_expire_elem(htab, l))
+				count++;
+		rcu_read_unlock();
+
+		cond_resched();
+	}
+
+	queue_delayed_work(system_unbound_wq, &htab->gc_work,
+			   count ? 0 : HTAB_GC_INTERVAL);
+}
+
+static void *__htab_timeout_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct htab_elem *l;
+
+	l = __htab_map_lookup_elem(map, key);
+	if (l && htab_expire_elem(htab, l))
+		l = NULL;
+
+	return l;
+}
+
+static void *htab_timeout_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct htab_elem *l = __htab_timeout_map_lookup_elem(map, key);
+
+	if (l)
+		return l->key + round_up(map->key_size, 8);
+	return NULL;
+}
+
+static int htab_timeout_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+{
+	struct bpf_insn *insn = insn_buf;
+	const int ret = BPF_REG_0;
+
+	BUILD_BUG_ON(!__same_type(&__htab_timeout_map_lookup_elem,
+		     (void *(*)(struct bpf_map *map, void *key))NULL));
+	*insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_timeout_map_lookup_elem));
+	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
+	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+				offsetof(struct htab_elem, key) +
+				round_up(map->key_size, 8));
+	return insn - insn_buf;
+}
+
+static void htab_timeout_map_seq_show_elem(struct bpf_map *map, void *key,
+					   struct seq_file *m)
+{
+	void *value;
+
+	rcu_read_lock();
+
+	value = htab_timeout_map_lookup_elem(map, key);
+	if (!value) {
+		rcu_read_unlock();
+		return;
+	}
+
+	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+	seq_puts(m, ": ");
+	btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
+	seq_puts(m, "\n");
+
+	rcu_read_unlock();
+}
+
+static struct bpf_map *htab_timeout_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_map *map = htab_map_alloc(attr);
+	struct bpf_htab *htab;
+
+	if (!IS_ERR(map)) {
+		htab = container_of(map, struct bpf_htab, map);
+		init_llist_head(&htab->gc_list);
+		INIT_DEFERRABLE_WORK(&htab->gc_work, htab_gc);
+		queue_delayed_work(system_unbound_wq, &htab->gc_work,
+				   HTAB_GC_INTERVAL);
+	}
+
+	return map;
+}
+
+static void htab_timeout_map_free(struct bpf_map *map)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+
+	cancel_delayed_work_sync(&htab->gc_work);
+	htab_map_free(map);
+}
+
+static int htab_timeout_map_btf_id;
+const struct bpf_map_ops htab_timeout_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = htab_map_alloc_check,
+	.map_alloc = htab_timeout_map_alloc,
+	.map_free = htab_timeout_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_lookup_elem = htab_timeout_map_lookup_elem,
+	.map_update_elem = htab_map_update_elem,
+	.map_delete_elem = htab_map_delete_elem,
+	.map_gen_lookup = htab_timeout_map_gen_lookup,
+	.map_seq_show_elem = htab_timeout_map_seq_show_elem,
+	.map_btf_name = "bpf_htab",
+	.map_btf_id = &htab_timeout_map_btf_id,
+	.iter_seq_info = &iter_seq_info,
+};
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c3bb03c8371f..2df15535895a 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -777,7 +777,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
 		    map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
 		    map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
 		    map->map_type != BPF_MAP_TYPE_INODE_STORAGE &&
-		    map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
+		    map->map_type != BPF_MAP_TYPE_TASK_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_TIMEOUT_HASH)
 			return -ENOTSUPP;
 		if (map->spin_lock_off + sizeof(struct bpf_spin_lock) >
 		    map->value_size) {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c001766adcbc..ac6ddfd7bddc 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -164,6 +164,7 @@ enum bpf_map_type {
 	BPF_MAP_TYPE_RINGBUF,
 	BPF_MAP_TYPE_INODE_STORAGE,
 	BPF_MAP_TYPE_TASK_STORAGE,
+	BPF_MAP_TYPE_TIMEOUT_HASH,
 };
 
 /* Note that tracing related programs such as
-- 
2.25.1

Re: [Patch bpf-next v4 1/3] bpf: introduce timeout hash map

[Cong Wang]

On Sat, Jan 16, 2021 at 8:22 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
> +static void htab_gc(struct work_struct *work)
> +{
> +       struct htab_elem *e, *tmp;
> +       struct llist_node *lhead;
> +       struct bpf_htab *htab;
> +       int i, count;
> +
> +       htab = container_of(work, struct bpf_htab, gc_work.work);
> +       lhead = llist_del_all(&htab->gc_list);
> +
> +       llist_for_each_entry_safe(e, tmp, lhead, gc_node) {
> +               unsigned long flags;
> +               struct bucket *b;
> +               u32 hash;
> +
> +               hash = e->hash;
> +               b = __select_bucket(htab, hash);
> +               if (htab_lock_bucket(htab, b, hash, &flags))
> +                       continue;
> +               hlist_nulls_del_rcu(&e->hash_node);
> +               atomic_set(&e->pending, 0);
> +               free_htab_elem(htab, e);
> +               htab_unlock_bucket(htab, b, hash, flags);
> +
> +               cond_resched();
> +       }
> +
> +       for (count = 0, i = 0; i < htab->n_buckets; i++) {

I just realized a followup fix is not folded into this patch, I
actually added a timestamp check here to avoid scanning the whole
table more frequently than once per second. It is clearly my mistake
to miss it when formatting this patchset.

I will send v5 after waiting for other feedback.

Thanks!

[Patch bpf-next v4 2/3] selftests/bpf: add test cases for bpf timeout map

[Cong Wang]

From: Cong Wang <cong.wang@bytedance.com>

Add some test cases in test_maps.c for timeout map, which focus
on testing timeout.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dongdong Wang <wangdongdong.6@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 tools/testing/selftests/bpf/test_maps.c | 47 +++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
index 51adc42b2b40..5e443d76512b 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -639,6 +639,52 @@ static void test_stackmap(unsigned int task, void *data)
 	close(fd);
 }
 
+static void test_timeout_map(unsigned int task, void *data)
+{
+	int val1 = 1, val2 = 2, val3 = 3;
+	int key1 = 1, key2 = 2, key3 = 3;
+	int fd;
+
+	fd = bpf_create_map(BPF_MAP_TYPE_TIMEOUT_HASH, sizeof(int), sizeof(int),
+			    3, map_flags);
+	if (fd < 0) {
+		printf("Failed to create timeout map '%s'!\n", strerror(errno));
+		exit(1);
+	}
+
+	/* Timeout after 1 secs */
+	assert(bpf_map_update_elem(fd, &key1, &val1, (u64)1000<<32) == 0);
+	/* Timeout after 2 secs */
+	assert(bpf_map_update_elem(fd, &key2, &val2, (u64)2000<<32) == 0);
+	/* Timeout after 10 secs */
+	assert(bpf_map_update_elem(fd, &key3, &val3, (u64)10000<<32) == 0);
+
+	sleep(1);
+	assert(bpf_map_lookup_elem(fd, &key1, &val1) != 0);
+	val2 = 0;
+	assert(bpf_map_lookup_elem(fd, &key2, &val2) == 0 && val2 == 2);
+
+	sleep(1);
+	assert(bpf_map_lookup_elem(fd, &key1, &val1) != 0);
+	assert(bpf_map_lookup_elem(fd, &key2, &val2) != 0);
+
+	/* Modify timeout to expire it earlier */
+	val3 = 0;
+	assert(bpf_map_lookup_elem(fd, &key3, &val3) == 0 && val3 == 3);
+	assert(bpf_map_update_elem(fd, &key3, &val3, (u64)1000<<32) == 0);
+	sleep(1);
+	assert(bpf_map_lookup_elem(fd, &key3, &val3) != 0);
+
+	/* Add one elem expired immediately and try to delete this expired */
+	assert(bpf_map_update_elem(fd, &key3, &val3, 0) == 0);
+	assert(bpf_map_delete_elem(fd, &key3) == -1 && errno == ENOENT);
+
+	/* Add one elem and let the map removal clean up */
+	assert(bpf_map_update_elem(fd, &key3, &val3, (u64)10000<<32) == 0);
+
+	close(fd);
+}
+
 #include <sys/ioctl.h>
 #include <arpa/inet.h>
 #include <sys/select.h>
@@ -1305,6 +1351,7 @@ static void test_map_stress(void)
 
 	run_parallel(100, test_arraymap, NULL);
 	run_parallel(100, test_arraymap_percpu, NULL);
+	run_parallel(100, test_timeout_map, NULL);
 }
 
 #define TASKS 1024
-- 
2.25.1

[Patch bpf-next v4 3/3] selftests/bpf: add timeout map check in map_ptr tests

[Cong Wang]

From: Cong Wang <cong.wang@bytedance.com>

Similar to regular hashmap test.

Acked-by: Andrey Ignatov <rdna@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dongdong Wang <wangdongdong.6@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 .../selftests/bpf/progs/map_ptr_kern.c        | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/map_ptr_kern.c b/tools/testing/selftests/bpf/progs/map_ptr_kern.c
index d8850bc6a9f1..424a9e76c93f 100644
--- a/tools/testing/selftests/bpf/progs/map_ptr_kern.c
+++ b/tools/testing/selftests/bpf/progs/map_ptr_kern.c
@@ -648,6 +648,25 @@ static inline int check_ringbuf(void)
 	return 1;
 }
 
+struct {
+	__uint(type, BPF_MAP_TYPE_TIMEOUT_HASH);
+	__uint(max_entries, MAX_ENTRIES);
+	__type(key, __u32);
+	__type(value, __u32);
+} m_timeout SEC(".maps");
+
+static inline int check_timeout_hash(void)
+{
+	struct bpf_htab *timeout_hash = (struct bpf_htab *)&m_timeout;
+	struct bpf_map *map = (struct bpf_map *)&m_timeout;
+
+	VERIFY(check_default(&timeout_hash->map, map));
+	VERIFY(timeout_hash->n_buckets == MAX_ENTRIES);
+	VERIFY(timeout_hash->elem_size == 64);
+
+	return 1;
+}
+
 SEC("cgroup_skb/egress")
 int cg_skb(void *ctx)
 {
@@ -679,6 +698,7 @@ int cg_skb(void *ctx)
 	VERIFY_TYPE(BPF_MAP_TYPE_SK_STORAGE, check_sk_storage);
 	VERIFY_TYPE(BPF_MAP_TYPE_DEVMAP_HASH, check_devmap_hash);
 	VERIFY_TYPE(BPF_MAP_TYPE_RINGBUF, check_ringbuf);
+	VERIFY_TYPE(BPF_MAP_TYPE_TIMEOUT_HASH, check_timeout_hash);
 
 	return 1;
 }
-- 
2.25.1