bpf: Expand map key argument of bpf_redirect_map to u64

For queueing packets in XDP we want to add a new redirect map type with
support for 64-bit indexes. To prepare fore this, expand the width of the
'key' argument to the bpf_redirect_map() helper. Since BPF registers are
always 64-bit, this should be safe to do after the fact.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20221108140601.149971-3-toke@redhat.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

include/linux/bpf.h

@@ -135,7 +135,7 @@ struct bpf_map_ops {
 	struct bpf_local_storage __rcu ** (*map_owner_storage_ptr)(void *owner);
 
 	/* Misc helpers.*/
-	int (*map_redirect)(struct bpf_map *map, u32 ifindex, u64 flags);
+	int (*map_redirect)(struct bpf_map *map, u64 key, 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

include/linux/filter.h

@@ -643,13 +643,13 @@ struct bpf_nh_params {
 };
 
 struct bpf_redirect_info {
-	u32 flags;
-	u32 tgt_index;
+	u64 tgt_index;
 	void *tgt_value;
 	struct bpf_map *map;
+	u32 flags;
+	u32 kern_flags;
 	u32 map_id;
 	enum bpf_map_type map_type;
-	u32 kern_flags;
 	struct bpf_nh_params nh;
 };
 
@@ -1504,7 +1504,7 @@ static inline bool bpf_sk_lookup_run_v6(struct net *net, int protocol,
 }
 #endif /* IS_ENABLED(CONFIG_IPV6) */
 
-static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifindex,
+static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u64 index,
 						  u64 flags, const u64 flag_mask,
 						  void *lookup_elem(struct bpf_map *map, u32 key))
 {
@@ -1515,7 +1515,7 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind
 	if (unlikely(flags & ~(action_mask | flag_mask)))
 		return XDP_ABORTED;
 
-	ri->tgt_value = lookup_elem(map, ifindex);
+	ri->tgt_value = lookup_elem(map, index);
 	if (unlikely(!ri->tgt_value) && !(flags & BPF_F_BROADCAST)) {
 		/* If the lookup fails we want to clear out the state in the
 		 * redirect_info struct completely, so that if an eBPF program
@@ -1527,7 +1527,7 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind
 		return flags & action_mask;
 	}
 
-	ri->tgt_index = ifindex;
+	ri->tgt_index = index;
 	ri->map_id = map->id;
 	ri->map_type = map->map_type;
 

include/uapi/linux/bpf.h

@@ -2647,7 +2647,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
+ * long bpf_redirect_map(struct bpf_map *map, u64 key, u64 flags)
  * 	Description
  * 		Redirect the packet to the endpoint referenced by *map* at
  * 		index *key*. Depending on its type, this *map* can contain

kernel/bpf/cpumap.c

@@ -667,9 +667,9 @@ 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)
+static int cpu_map_redirect(struct bpf_map *map, u64 index, u64 flags)
 {
-	return __bpf_xdp_redirect_map(map, ifindex, flags, 0,
+	return __bpf_xdp_redirect_map(map, index, flags, 0,
 				      __cpu_map_lookup_elem);
 }
 

kernel/bpf/devmap.c

@@ -992,14 +992,14 @@ 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)
+static int dev_map_redirect(struct bpf_map *map, u64 ifindex, u64 flags)
 {
 	return __bpf_xdp_redirect_map(map, ifindex, flags,
 				      BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS,
 				      __dev_map_lookup_elem);
 }
 
-static int dev_hash_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+static int dev_hash_map_redirect(struct bpf_map *map, u64 ifindex, u64 flags)
 {
 	return __bpf_xdp_redirect_map(map, ifindex, flags,
 				      BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS,

kernel/bpf/verifier.c

@@ -14384,7 +14384,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
 			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));
+				     (int (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
 			BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
 				     (int (*)(struct bpf_map *map,
 					      bpf_callback_t callback_fn,

net/core/filter.c

@@ -4414,10 +4414,10 @@ 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,
+BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u64, key,
 	   u64, flags)
 {
-	return map->ops->map_redirect(map, ifindex, flags);
+	return map->ops->map_redirect(map, key, flags);
 }
 
 static const struct bpf_func_proto bpf_xdp_redirect_map_proto = {

net/xdp/xskmap.c

@@ -231,9 +231,9 @@ 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)
+static int xsk_map_redirect(struct bpf_map *map, u64 index, u64 flags)
 {
-	return __bpf_xdp_redirect_map(map, ifindex, flags, 0,
+	return __bpf_xdp_redirect_map(map, index, flags, 0,
 				      __xsk_map_lookup_elem);
 }