From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 16 Jul 2026 18:25:50 +0000 (+0200)
Subject: ucode-mod-bpf: add support for keyless maps
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ec06937a5ab4b45128d58d2e0d5cfb5c93df3ea3;p=thirdparty%2Fopenwrt.git

ucode-mod-bpf: add support for keyless maps

Queue and stack maps have zero-sized keys and require a NULL key
pointer; the kernel rejects any non-NULL key with EINVAL, making
these maps unusable. Accept a null key argument on maps without a
key, mapping get() to peek, set() to push and delete() with return
to pop.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/package/utils/ucode-mod-bpf/src/bpf.c b/package/utils/ucode-mod-bpf/src/bpf.c
index c34772bff5d..d32c7ec45eb 100644
--- a/package/utils/ucode-mod-bpf/src/bpf.c
+++ b/package/utils/ucode-mod-bpf/src/bpf.c
@@ -369,6 +369,26 @@ uc_bpf_map_arg(uc_value_t *val, const char *kind, unsigned int size,
 	err_return(EINVAL, "%s size mismatch (expected: %d)", kind, size);
 }
 
+static bool
+uc_bpf_map_key_arg(struct uc_bpf_map *map, uc_value_t *a_key, uint64_t *buf,
+		   void **key)
+{
+	if (!map->key_size) {
+		if (a_key) {
+			set_error(EINVAL, "map has no key");
+			return false;
+		}
+
+		*key = NULL;
+
+		return true;
+	}
+
+	*key = uc_bpf_map_arg(a_key, "key", map->key_size, buf);
+
+	return *key != NULL;
+}
+
 static bool
 uc_bpf_map_is_percpu(struct uc_bpf_map *map)
 {
@@ -488,8 +508,7 @@ uc_bpf_map_get(uc_vm_t *vm, size_t nargs)
 	if (!map)
 		err_return(EINVAL, NULL);
 
-	key = uc_bpf_map_arg(a_key, "key", map->key_size, &key_int);
-	if (!key)
+	if (!uc_bpf_map_key_arg(map, a_key, &key_int, &key))
 		return NULL;
 
 	if (!uc_bpf_map_val_len(map, &val_len, &num_cpus))
@@ -518,8 +537,7 @@ uc_bpf_map_set(uc_vm_t *vm, size_t nargs)
 	if (!map)
 		err_return(EINVAL, NULL);
 
-	key = uc_bpf_map_arg(a_key, "key", map->key_size, &key_int);
-	if (!key)
+	if (!uc_bpf_map_key_arg(map, a_key, &key_int, &key))
 		return NULL;
 
 	if (!uc_bpf_map_val_len(map, &val_len, &num_cpus))
@@ -558,8 +576,7 @@ uc_bpf_map_delete(uc_vm_t *vm, size_t nargs)
 	if (!map)
 		err_return(EINVAL, NULL);
 
-	key = uc_bpf_map_arg(a_key, "key", map->key_size, &key_int);
-	if (!key)
+	if (!uc_bpf_map_key_arg(map, a_key, &key_int, &key))
 		return NULL;
 
 	if (!ucv_is_truish(a_return)) {