On 2/27/21 1:21 PM, Björn Töpel wrote:
[...]
Look good. Small nits inline I had originally fixed up locally before glancing
at 2/2:
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 4c730863fa77..3d3e89a37e62 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -118,6 +118,9 @@ struct bpf_map_ops {
void *owner, u32 size);
struct bpf_local_storage __rcu ** (*map_owner_storage_ptr)(void *owner);
+ /* XDP helpers.*/
If this really needs a comment, I'd say 'Misc helpers' since we might later also
add implementations for tc and everything can be inferred from the code anyway.
+ int (*map_redirect)(struct bpf_map *map, u32 ifindex, u64 flags);
+
[...]
static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9fe90ce52a65..b6c44b85e960 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 +12061,8 @@ 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));
I added a linebreak here.
patch_map_ops_generic:
switch (insn->imm) {
case BPF_FUNC_map_lookup_elem:
@@ -12085,6 +12089,9 @@ 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;
Ditto so it matches the rest.
+ continue;
}
goto patch_call_imm;
diff --git a/net/core/filter.c b/net/core/filter.c
index 13bcf248ee7b..960299a3744f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3934,22 +3934,6 @@ void xdp_do_flush(void)
}
EXPORT_SYMBOL_GPL(xdp_do_flush);
-static inline void *__xdp_map_lookup_elem(struct bpf_map *map, u32 index)
-{
- switch (map->map_type) {
- case BPF_MAP_TYPE_DEVMAP:
- return __dev_map_lookup_elem(map, index);
- case BPF_MAP_TYPE_DEVMAP_HASH:
- return __dev_map_hash_lookup_elem(map, index);
- case BPF_MAP_TYPE_CPUMAP:
- return __cpu_map_lookup_elem(map, index);
- case BPF_MAP_TYPE_XSKMAP:
- return __xsk_map_lookup_elem(map, index);
- default:
- return NULL;
- }
-}
-
void bpf_clear_redirect_map(struct bpf_map *map)
{
struct bpf_redirect_info *ri;
@@ -4103,28 +4087,7 @@ static const struct bpf_func_proto
bpf_xdp_redirect_proto = {
BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u32, ifindex,
u64, flags)
{
- struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
-
- /* Lower bits of the flags are used as return code on lookup failure */
- if (unlikely(flags > XDP_TX))
- return XDP_ABORTED;
-
- ri->tgt_value = __xdp_map_lookup_elem(map, ifindex);
- if (unlikely(!ri->tgt_value)) {
- /* If the lookup fails we want to clear out the state in the
- * redirect_info struct completely, so that if an eBPF program
- * performs multiple lookups, the last one always takes
- * precedence.
- */
- WRITE_ONCE(ri->map, NULL);
- return flags;
- }
-
- ri->flags = flags;
- ri->tgt_index = ifindex;
- WRITE_ONCE(ri->map, map);
-
- return XDP_REDIRECT;
+ return map->ops->map_redirect(map, ifindex, flags);
}
static const struct bpf_func_proto bpf_xdp_redirect_map_proto = {
diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c
index 113fd9017203..711acb3636b3 100644
--- a/net/xdp/xskmap.c
+++ b/net/xdp/xskmap.c
@@ -125,6 +125,18 @@ static int xsk_map_gen_lookup(struct bpf_map *map, struct
bpf_insn *insn_buf)
return insn - insn_buf;
}
+static void *__xsk_map_lookup_elem(struct bpf_map *map, u32 key)
+{
+ struct xsk_map *m = container_of(map, struct xsk_map, map);
+ struct xdp_sock *xs;
+
+ if (key >= map->max_entries)
+ return NULL;
+
+ xs = READ_ONCE(m->xsk_map[key]);
Just 'return READ_ONCE(m->xsk_map[key]);'
+ return xs;
+}
+
static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
{
WARN_ON_ONCE(!rcu_read_lock_held());
@@ -215,6 +227,11 @@ static int xsk_map_delete_elem(struct bpf_map *map, void
*key)
return 0;
}
+static int xsk_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags,
__xsk_map_lookup_elem);
+}
+
void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
struct xdp_sock **map_entry)
{
@@ -247,4 +264,5 @@ const struct bpf_map_ops xsk_map_ops = {
.map_check_btf = map_check_no_btf,
.map_btf_name = "xsk_map",
.map_btf_id = &xsk_map_btf_id,
+ .map_redirect = xsk_map_redirect,
};
