On 2/26/21 12:23 PM, Björn Töpel wrote:
From: Björn Töpel <bjorn.topel@xxxxxxxxx>
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@xxxxxxxxx>
---
include/linux/bpf.h | 26 ++++++--------------------
include/linux/filter.h | 27 +++++++++++++++++++++++++++
include/net/xdp_sock.h | 19 -------------------
kernel/bpf/cpumap.c | 8 +++++++-
kernel/bpf/devmap.c | 16 ++++++++++++++--
kernel/bpf/verifier.c | 11 +++++++++--
net/core/filter.c | 39 +--------------------------------------
net/xdp/xskmap.c | 18 ++++++++++++++++++
8 files changed, 82 insertions(+), 82 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cccaef1088ea..a44ba904ca37 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -117,6 +117,9 @@ struct bpf_map_ops {
void *owner, u32 size);
struct bpf_local_storage __rcu ** (*map_owner_storage_ptr)(void *owner);
+ /* XDP helpers.*/
+ int (*xdp_redirect_map)(struct bpf_map *map, u32 ifindex, u64 flags);
+
/* map_meta_equal must be implemented for maps that can be
* used as an inner map. It is a runtime check to ensure
* an inner map can be inserted to an outer map.
[...]
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1dda9d81f12c..96705a49225e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5409,7 +5409,8 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
func_id != BPF_FUNC_map_delete_elem &&
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_map_peek_elem &&
+ func_id != BPF_FUNC_redirect_map)
return 0;
if (map == NULL) {
@@ -11762,7 +11763,8 @@ static int fixup_bpf_calls(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;
@@ -11804,6 +11806,8 @@ static int fixup_bpf_calls(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->xdp_redirect_map,
+ (int (*)(struct bpf_map *map, u32 ifindex, u64 flags))NULL));
patch_map_ops_generic:
switch (insn->imm) {
case BPF_FUNC_map_lookup_elem:
@@ -11830,6 +11834,9 @@ static int fixup_bpf_calls(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->xdp_redirect_map) - __bpf_call_base;
Small nit: I would name the generic callback ops->map_redirect so that this is in line with
the general naming convention for the map ops. Otherwise this looks much better, thx!
+ continue;
}
goto patch_call_imm;
