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Message-Id: <20210220153056.111968-2-bjorn.topel@gmail.com>
Date: Sat, 20 Feb 2021 16:30:55 +0100
From: Björn Töpel <bjorn.topel@...il.com>
To: ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org,
bpf@...r.kernel.org
Cc: Björn Töpel <bjorn.topel@...el.com>,
maciej.fijalkowski@...el.com, hawk@...nel.org, toke@...hat.com,
magnus.karlsson@...el.com, john.fastabend@...il.com,
kuba@...nel.org, davem@...emloft.net
Subject: [PATCH bpf-next v2 1/2] bpf, xdp: per-map bpf_redirect_map functions for XDP
From: Björn Töpel <bjorn.topel@...el.com>
Currently the bpf_redirect_map() implementation dispatches to the
correct map-lookup function via a switch-statement. To avoid the
dispatching, this change adds one bpf_redirect_map() implementation per
map. Correct function is automatically selected by the BPF verifier.
v1->v2 : Re-added comment. (Toke)
rfc->v1: Get rid of the macro and use __always_inline. (Jesper)
Acked-by: Toke Høiland-Jørgensen <toke@...hat.com>
Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
---
include/linux/bpf.h | 20 ++++++++------
include/linux/filter.h | 2 ++
include/net/xdp_sock.h | 6 ++--
kernel/bpf/cpumap.c | 2 +-
kernel/bpf/devmap.c | 4 +--
kernel/bpf/verifier.c | 28 +++++++++++--------
net/core/filter.c | 62 ++++++++++++++++++++++++++++--------------
7 files changed, 76 insertions(+), 48 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cccaef1088ea..3dd186eeaf98 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -314,12 +314,14 @@ enum bpf_return_type {
RET_PTR_TO_BTF_ID, /* returns a pointer to a btf_id */
};
+typedef u64 (*bpf_func_proto_func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
+
/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
* to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
* instructions after verifying
*/
struct bpf_func_proto {
- u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
+ bpf_func_proto_func func;
bool gpl_only;
bool pkt_access;
enum bpf_return_type ret_type;
@@ -1429,9 +1431,11 @@ struct btf *bpf_get_btf_vmlinux(void);
/* Map specifics */
struct xdp_buff;
struct sk_buff;
+struct bpf_dtab_netdev;
+struct bpf_cpu_map_entry;
-struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
-struct bpf_dtab_netdev *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key);
+void *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
+void *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key);
void __dev_flush(void);
int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
struct net_device *dev_rx);
@@ -1441,7 +1445,7 @@ int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
struct bpf_prog *xdp_prog);
bool dev_map_can_have_prog(struct bpf_map *map);
-struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key);
+void *__cpu_map_lookup_elem(struct bpf_map *map, u32 key);
void __cpu_map_flush(void);
int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,
struct net_device *dev_rx);
@@ -1568,14 +1572,12 @@ static inline int bpf_obj_get_user(const char __user *pathname, int flags)
return -EOPNOTSUPP;
}
-static inline struct net_device *__dev_map_lookup_elem(struct bpf_map *map,
- u32 key)
+static inline void *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
{
return NULL;
}
-static inline struct net_device *__dev_map_hash_lookup_elem(struct bpf_map *map,
- u32 key)
+static inline void *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
{
return NULL;
}
@@ -1615,7 +1617,7 @@ static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst,
}
static inline
-struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
+void *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
{
return NULL;
}
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 3b00fc906ccd..1dedcf66b694 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1472,4 +1472,6 @@ static inline bool bpf_sk_lookup_run_v6(struct net *net, int protocol,
}
#endif /* IS_ENABLED(CONFIG_IPV6) */
+bpf_func_proto_func get_xdp_redirect_func(enum bpf_map_type map_type);
+
#endif /* __LINUX_FILTER_H__ */
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index cc17bc957548..da4139a58630 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -80,8 +80,7 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp);
int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp);
void __xsk_map_flush(void);
-static inline struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map,
- u32 key)
+static inline 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;
@@ -109,8 +108,7 @@ static inline void __xsk_map_flush(void)
{
}
-static inline struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map,
- u32 key)
+static inline void *__xsk_map_lookup_elem(struct bpf_map *map, u32 key)
{
return NULL;
}
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 5d1469de6921..a4d2cb93cd69 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)
+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;
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 85d9d1b72a33..37ac4cde9713 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)
+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)
+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;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 3d34ba492d46..b5fb0c4e911a 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) {
@@ -11860,17 +11861,22 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
}
patch_call_imm:
- fn = env->ops->get_func_proto(insn->imm, env->prog);
- /* all functions that have prototype and verifier allowed
- * programs to call them, must be real in-kernel functions
- */
- if (!fn->func) {
- verbose(env,
- "kernel subsystem misconfigured func %s#%d\n",
- func_id_name(insn->imm), insn->imm);
- return -EFAULT;
+ if (insn->imm == BPF_FUNC_redirect_map) {
+ aux = &env->insn_aux_data[i];
+ map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+ insn->imm = get_xdp_redirect_func(map_ptr->map_type) - __bpf_call_base;
+ } else {
+ fn = env->ops->get_func_proto(insn->imm, env->prog);
+ /* all functions that have prototype and verifier allowed
+ * programs to call them, must be real in-kernel functions
+ */
+ if (!fn->func) {
+ verbose(env, "kernel subsystem misconfigured func %s#%d\n",
+ func_id_name(insn->imm), insn->imm);
+ return -EFAULT;
+ }
+ insn->imm = fn->func - __bpf_call_base;
}
- insn->imm = fn->func - __bpf_call_base;
}
/* Since poke tab is now finalized, publish aux to tracker. */
diff --git a/net/core/filter.c b/net/core/filter.c
index adfdad234674..eeecd95aa38f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3944,22 +3944,6 @@ 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;
@@ -4110,16 +4094,16 @@ static const struct bpf_func_proto bpf_xdp_redirect_proto = {
.arg2_type = ARG_ANYTHING,
};
-BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u32, ifindex,
- u64, flags)
+static __always_inline s64 __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifindex, u64 flags,
+ void *lookup_elem(struct bpf_map *map,
+ u32 key))
{
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);
+ ri->tgt_value = 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
@@ -4137,8 +4121,44 @@ BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u32, ifindex,
return XDP_REDIRECT;
}
+BPF_CALL_3(bpf_xdp_redirect_devmap, struct bpf_map *, map, u32, ifindex, u64, flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __dev_map_lookup_elem);
+}
+
+BPF_CALL_3(bpf_xdp_redirect_devmap_hash, struct bpf_map *, map, u32, ifindex, u64, flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __dev_map_hash_lookup_elem);
+}
+
+BPF_CALL_3(bpf_xdp_redirect_cpumap, struct bpf_map *, map, u32, ifindex, u64, flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __cpu_map_lookup_elem);
+}
+
+BPF_CALL_3(bpf_xdp_redirect_xskmap, struct bpf_map *, map, u32, ifindex, u64, flags)
+{
+ return __bpf_xdp_redirect_map(map, ifindex, flags, __xsk_map_lookup_elem);
+}
+
+bpf_func_proto_func get_xdp_redirect_func(enum bpf_map_type map_type)
+{
+ switch (map_type) {
+ case BPF_MAP_TYPE_DEVMAP:
+ return bpf_xdp_redirect_devmap;
+ case BPF_MAP_TYPE_DEVMAP_HASH:
+ return bpf_xdp_redirect_devmap_hash;
+ case BPF_MAP_TYPE_CPUMAP:
+ return bpf_xdp_redirect_cpumap;
+ case BPF_MAP_TYPE_XSKMAP:
+ return bpf_xdp_redirect_xskmap;
+ default:
+ return NULL;
+ }
+}
+
+/* NB! .func is NULL! get_xdp_redirect_func() is used instead! */
static const struct bpf_func_proto bpf_xdp_redirect_map_proto = {
- .func = bpf_xdp_redirect_map,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
--
2.27.0
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