Add bpf_lua_type function

Author: VictorNogueiraRio

include/uapi/linux/bpf.h

@@ -2241,7 +2241,8 @@ union bpf_attr {
 	FN(lua_pushstring),		\
 	FN(lua_toboolean),		\
 	FN(lua_tointeger),		\
-	FN(lua_newpacket),
+	FN(lua_newpacket),		\
+	FN(lua_type),
 	/* #endif CONFIG_XDP_LUA */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper

net/core/filter.c

@@ -5048,6 +5048,19 @@ static const struct bpf_func_proto bpf_lua_newpacket_proto = {
 	.arg1_type	= ARG_PTR_TO_CTX,
 	.arg2_type	= ARG_ANYTHING,
 };
+
+BPF_CALL_2(bpf_lua_type, struct xdp_buff *, ctx, int, index) {
+       return lua_type(ctx->L, index);
+}
+
+static const struct bpf_func_proto bpf_lua_type_proto = {
+       .func           = bpf_lua_type,
+       .gpl_only       = false,
+       .pkt_access     = false,
+       .ret_type       = RET_INTEGER,
+       .arg1_type      = ARG_PTR_TO_CTX,
+       .arg2_type      = ARG_ANYTHING,
+};
 #endif /* CONFIG_XDP_LUA */
 
 bool bpf_helper_changes_pkt_data(void *func)
@@ -5134,6 +5147,8 @@ bpf_base_func_proto(enum bpf_func_id func_id)
 		return &bpf_lua_tointeger_proto;
 	case BPF_FUNC_lua_newpacket:
 		return &bpf_lua_newpacket_proto;
+	case BPF_FUNC_lua_type:
+		return &bpf_lua_type_proto;
 #endif /* CONFIG_XDP_LUA */
 	default:
 		return NULL;

tools/include/uapi/linux/bpf.h

@@ -2241,7 +2241,8 @@ union bpf_attr {
 	FN(lua_pushstring),		\
 	FN(lua_toboolean),		\
 	FN(lua_tointeger),		\
-	FN(lua_newpacket),
+	FN(lua_newpacket),		\
+	FN(lua_type),
 	/* #endif CONFIG_XDP_LUA */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper

tools/testing/selftests/bpf/bpf_helpers.h

@@ -175,6 +175,8 @@ static int (*bpf_lua_tointeger)(void *ctx, int index) =
     (void *)BPF_FUNC_lua_tointeger;
 static int (*bpf_lua_newpacket)(void *ctx, int offset) =
     (void *)BPF_FUNC_lua_newpacket;
+static int (*bpf_lua_type)(void *ctx, int index) =
+    (void *)BPF_FUNC_lua_type;
 /* #endif CONFIG_XDP_LUA */
 
 /* llvm builtin functions that eBPF C program may use to