Define a proper maximum Lua script length

Author: VictorNogueiraRio

include/uapi/linux/if_link.h

@@ -926,6 +926,7 @@ enum {
 					 XDP_FLAGS_HW_MODE)
 #define XDP_FLAGS_MASK			(XDP_FLAGS_UPDATE_IF_NOEXIST | \
 					 XDP_FLAGS_MODES)
+#define LUA_MAX_SCRIPT_LEN			8192
 
 /* These are stored into IFLA_XDP_ATTACHED on dump. */
 enum {

net/core/rtnetlink.c

@@ -1791,7 +1791,7 @@ static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = {
 	[IFLA_XDP_FLAGS]	= { .type = NLA_U32 },
 	[IFLA_XDP_PROG_ID]	= { .type = NLA_U32 },
 #ifdef CONFIG_XDP_LUA
-	[IFLA_XDP_LUA_PROG]	= { .type = NLA_STRING, .len = 8192 },
+	[IFLA_XDP_LUA_PROG]	= { .type = NLA_STRING, .len = LUA_MAX_SCRIPT_LEN },
 #endif  /* CONFIG_XDP_LUA */
 };
 

tools/include/uapi/linux/if_link.h

@@ -927,6 +927,7 @@ enum {
 #define XDP_FLAGS_MASK			(XDP_FLAGS_UPDATE_IF_NOEXIST | \
 					 XDP_FLAGS_MODES)
 
+#define LUA_MAX_SCRIPT_LEN			8192
 /* These are stored into IFLA_XDP_ATTACHED on dump. */
 enum {
 	XDP_ATTACHED_NONE = 0,

tools/lib/bpf/bpf.c

@@ -630,7 +630,7 @@ int bpf_set_link_xdp_lua_prog(char *lua_prog)
 	struct {
 		struct nlmsghdr  nh;
 		struct ifinfomsg ifinfo;
-		char             attrbuf[64];
+		char             attrbuf[LUA_MAX_SCRIPT_LEN + 64];
 	} req;
 	struct nlmsghdr *nh;
 	struct nlmsgerr *err;