bpf, xdp: Make bpf_redirect_map() a map operation
Currently the bpf_redirect_map() implementation dispatches to the
correct map-lookup function via a switch-statement. To avoid the
dispatching, this change adds bpf_redirect_map() as a map
operation. Each map provides its bpf_redirect_map() version, and
correct function is automatically selected by the BPF verifier.
A nice side-effect of the code movement is that the map lookup
functions are now local to the map implementation files, which removes
one additional function call.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210308112907.559576-2-bjorn.topel@gmail.com
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 5d1469d..7352d41 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -563,7 +563,7 @@ static void cpu_map_free(struct bpf_map *map)
kfree(cmap);
}
-struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
+static void *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
struct bpf_cpu_map_entry *rcpu;
@@ -600,6 +600,11 @@ static int cpu_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
return 0;
}
+static int cpu_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __cpu_map_lookup_elem);
+}
+
static int cpu_map_btf_id;
const struct bpf_map_ops cpu_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
@@ -612,6 +617,7 @@ const struct bpf_map_ops cpu_map_ops = {
.map_check_btf = map_check_no_btf,
.map_btf_name = "bpf_cpu_map",
.map_btf_id = &cpu_map_btf_id,
+ .map_redirect = cpu_map_redirect,
};
static void bq_flush_to_queue(struct xdp_bulk_queue *bq)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 85d9d1b..f7f4244 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -258,7 +258,7 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
return 0;
}
-struct bpf_dtab_netdev *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
+static void *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
struct hlist_head *head = dev_map_index_hash(dtab, key);
@@ -392,7 +392,7 @@ void __dev_flush(void)
* update happens in parallel here a dev_put wont happen until after reading the
* ifindex.
*/
-struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
+static void *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
struct bpf_dtab_netdev *obj;
@@ -735,6 +735,16 @@ static int dev_map_hash_update_elem(struct bpf_map *map, void *key, void *value,
map, key, value, map_flags);
}
+static int dev_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __dev_map_lookup_elem);
+}
+
+static int dev_hash_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __dev_map_hash_lookup_elem);
+}
+
static int dev_map_btf_id;
const struct bpf_map_ops dev_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
@@ -747,6 +757,7 @@ const struct bpf_map_ops dev_map_ops = {
.map_check_btf = map_check_no_btf,
.map_btf_name = "bpf_dtab",
.map_btf_id = &dev_map_btf_id,
+ .map_redirect = dev_map_redirect,
};
static int dev_map_hash_map_btf_id;
@@ -761,6 +772,7 @@ const struct bpf_map_ops dev_map_hash_ops = {
.map_check_btf = map_check_no_btf,
.map_btf_name = "bpf_dtab",
.map_btf_id = &dev_map_hash_map_btf_id,
+ .map_redirect = dev_hash_map_redirect,
};
static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9fe90ce5..97eb0b2 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5582,7 +5582,8 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
func_id != BPF_FUNC_map_push_elem &&
func_id != BPF_FUNC_map_pop_elem &&
func_id != BPF_FUNC_map_peek_elem &&
- func_id != BPF_FUNC_for_each_map_elem)
+ func_id != BPF_FUNC_for_each_map_elem &&
+ func_id != BPF_FUNC_redirect_map)
return 0;
if (map == NULL) {
@@ -12017,7 +12018,8 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
insn->imm == BPF_FUNC_map_delete_elem ||
insn->imm == BPF_FUNC_map_push_elem ||
insn->imm == BPF_FUNC_map_pop_elem ||
- insn->imm == BPF_FUNC_map_peek_elem)) {
+ insn->imm == BPF_FUNC_map_peek_elem ||
+ insn->imm == BPF_FUNC_redirect_map)) {
aux = &env->insn_aux_data[i + delta];
if (bpf_map_ptr_poisoned(aux))
goto patch_call_imm;
@@ -12059,6 +12061,9 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
(int (*)(struct bpf_map *map, void *value))NULL));
BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
(int (*)(struct bpf_map *map, void *value))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_redirect,
+ (int (*)(struct bpf_map *map, u32 ifindex, u64 flags))NULL));
+
patch_map_ops_generic:
switch (insn->imm) {
case BPF_FUNC_map_lookup_elem:
@@ -12085,6 +12090,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
insn->imm = BPF_CAST_CALL(ops->map_peek_elem) -
__bpf_call_base;
continue;
+ case BPF_FUNC_redirect_map:
+ insn->imm = BPF_CAST_CALL(ops->map_redirect) -
+ __bpf_call_base;
+ continue;
}
goto patch_call_imm;
