add XDPLua

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "lib/lunatik"]
+	path = lib/lunatik
+	url = https://github.com/luainkernel/lunatik.git

include/linux/filter.h

@@ -1268,4 +1268,14 @@ struct bpf_sockopt_kern {
 	s32		retval;
 };
 
+#ifdef CONFIG_XDP_LUA
+extern struct list_head lua_state_cpu_list;
+
+struct lua_state_cpu {
+	struct lua_State 	*L;
+	int			cpu;
+	struct list_head	list;
+};
+#endif /* CONFIG_XDP_LUA */
+
 #endif /* __LINUX_FILTER_H__ */

include/linux/netdevice.h

@@ -3772,6 +3772,10 @@ u32 __dev_xdp_query(struct net_device *dev, bpf_op_t xdp_op,
 		    enum bpf_netdev_command cmd);
 int xdp_umem_query(struct net_device *dev, u16 queue_id);
 
+#ifdef CONFIG_XDP_LUA
+int generic_xdp_lua_install_prog(char *lua_prog);
+#endif /* CONFIG_XDP_LUA */
+
 int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
 int dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
 bool is_skb_forwardable(const struct net_device *dev,

include/net/xdp.h

@@ -70,6 +70,10 @@ struct xdp_buff {
 	void *data_hard_start;
 	unsigned long handle;
 	struct xdp_rxq_info *rxq;
+#ifdef CONFIG_XDP_LUA
+	struct sk_buff *skb;
+	struct lua_State *L;
+#endif /* CONFIG_XDP_LUA */
 };
 
 struct xdp_frame {

include/uapi/linux/bpf.h

@@ -2890,6 +2890,73 @@ union bpf_attr {
  *		Obtain the 64bit jiffies
  *	Return
  *		The 64 bit jiffies
+ *
+ * void bpf_lua_pcall(void *ctx, char *funcname, int num_args, int num_rets)
+ *	Description
+ *		Calls Lua function funcname with the given nargs arguments in protected mode
+ *
+ * void bpf_lua_pop(void *ctx, int n)
+ *	Description
+ *		Pops n elements from the Lua stack
+ *
+ * void bpf_lua_pushinteger(void *ctx, int num)
+ *	Description
+ *		Pushes an integer with value n onto the Lua stack.
+ *
+ * void bpf_lua_pushlightuserdata(void *ctx, void *ptr)
+ *	Description
+ *		Pushes a light userdata onto the Lua stack.
+ *		Userdata represent C values in Lua.
+ *		A light userdata represents a pointer, a void*.
+ *		It is a value (like a number): you do not create it,
+ *		it has no individual metatable, and it is not collected
+ *		(as it was never created).
+ *		A light userdata is equal to "any" light userdata with
+ *		the same C address.
+ *
+ * void bpf_lua_pushlstring(void *ctx, const char *s, size_t len)
+ *	Description
+ *		Pushes the string pointed to by s with size len onto the stack.
+ *		Lua makes (or reuses) an internal copy of the given string,
+ *		so the memory at s can be freed or reused immediately after the
+ *		function returns.
+ *		The string can contain any binary data, including embedded zeros.
+ *
+ * void bpf_lua_pushmap(void *ctx, void *map)
+ *	Description
+ *		Pushes a BPF map onto the Lua stack
+ *
+ * void bpf_lua_pushskb(void *ctx)
+ *	Description
+ *		Pushes an SKB structure onto the Lua stack
+ *
+ * void bpf_lua_pushstring(void *ctx, const char *s)
+ *	Description
+ *		Pushes the zero-terminated string pointed to by s onto the stack.
+ *		Lua makes (or reuses) an internal copy of the given string,
+ *		so the memory at s can be freed or reused immediately after the
+ *		function returns.
+ *
+ * void bpf_lua_setstate(void *ctx)
+ *	Description
+ *		Sets the Lua state pointer in the context struct
+ *
+ * int bpf_lua_toboolean(void *ctx, int index)
+ *	Description
+ *		Converts the Lua value at the given index to a C
+ *		boolean value (0 or 1)
+ *	Return
+ *		1 if the value in the given index of the Lua stack is
+ *		different from from false or null, otherwise returns 0
+ *
+ * int bpf_lua_tointeger(void *ctx, int index)
+ *	Description
+ *		Converts the Lua value at the given index of the Lua stack
+ *		to the signed integral type lua_Integer.
+ *	Return
+ *		The converted Lua value at the given index, if the value is
+ *		convertible to an integer(see the Lua manual for more details
+ *		on type conversion); otherwise returns 0
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3010,7 +3077,20 @@ union bpf_attr {
 	FN(probe_read_kernel_str),	\
 	FN(tcp_send_ack),		\
 	FN(send_signal_thread),		\
-	FN(jiffies64),
+	FN(jiffies64),	\
+	/* #ifdef CONFIG_XDP_LUA */	\
+	FN(lua_pcall),			\
+	FN(lua_pop),			\
+	FN(lua_pushinteger),		\
+	FN(lua_pushlightuserdata),	\
+	FN(lua_pushlstring),		\
+	FN(lua_pushmap),		\
+	FN(lua_pushskb),		\
+	FN(lua_pushstring),		\
+	FN(lua_setstate),		\
+	FN(lua_toboolean),		\
+	FN(lua_tointeger),
+	/* #endif CONFIG_XDP_LUA */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call

include/uapi/linux/if_link.h

@@ -984,6 +984,9 @@ enum {
 	IFLA_XDP_DRV_PROG_ID,
 	IFLA_XDP_SKB_PROG_ID,
 	IFLA_XDP_HW_PROG_ID,
+#ifdef CONFIG_XDP_LUA
+	IFLA_XDP_LUA_PROG,
+#endif /* CONFIG_XDP_LUA */
 	__IFLA_XDP_MAX,
 };
 

init/Kconfig

@@ -1307,6 +1307,12 @@ config HAVE_PCSPKR_PLATFORM
 config BPF
 	bool
 
+config LUNATIK
+	bool "Lunatik"
+	default n
+	help
+	  Support for the Lua interpreter
+
 menuconfig EXPERT
 	bool "Configure standard kernel features (expert users)"
 	# Unhide debug options, to make the on-by-default options visible

lib/Makefile

@@ -300,3 +300,6 @@ obj-$(CONFIG_OBJAGG) += objagg.o
 
 # KUnit tests
 obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
+subdir-ccflags-y += -I$(srctree)/lib/lunatik/lua \
+	            -D_KERNEL
+obj-$(CONFIG_LUNATIK) += lunatik/

net/core/Makefile

@@ -8,6 +8,8 @@ obj-y := sock.o request_sock.o skbuff.o datagram.o stream.o scm.o \
 
 obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
 
+CFLAGS_dev.o = -Ilib/lunatik/lua/ -D_KERNEL
+CFLAGS_filter.o = -Ilib/lunatik/lua/ -D_KERNEL
 obj-y		     += dev.o dev_addr_lists.o dst.o netevent.o \
 			neighbour.o rtnetlink.o utils.o link_watch.o filter.o \
 			sock_diag.o dev_ioctl.o tso.o sock_reuseport.o \

net/core/dev.c

@@ -68,6 +68,12 @@
  *				        - netif_rx() feedback
  */
 
+#ifdef CONFIG_XDP_LUA
+#include <lua.h>
+#include <lauxlib.h>
+#include <lualib.h>
+#endif /* CONFIG_XDP_LUA */
+
 #include <linux/uaccess.h>
 #include <linux/bitops.h>
 #include <linux/capability.h>
@@ -164,6 +170,10 @@ static int call_netdevice_notifiers_extack(unsigned long val,
 					   struct netlink_ext_ack *extack);
 static struct napi_struct *napi_by_id(unsigned int napi_id);
 
+#ifdef CONFIG_XDP_LUA
+struct list_head lua_state_cpu_list;
+#endif /* CONFIG_XDP_LUA */
+
 /*
  * The @dev_base_head list is protected by @dev_base_lock and the rtnl
  * semaphore.
@@ -4556,6 +4566,9 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb,
 
 	rxqueue = netif_get_rxqueue(skb);
 	xdp->rxq = &rxqueue->xdp_rxq;
+#ifdef CONFIG_XDP_LUA
+	xdp->skb = skb;
+#endif /* CONFIG_XDP_LUA */
 
 	act = bpf_prog_run_xdp(xdp_prog, xdp);
 
@@ -5366,6 +5379,22 @@ static int generic_xdp_install(struct net_device *dev, struct netdev_bpf *xdp)
 	return ret;
 }
 
+#ifdef CONFIG_XDP_LUA
+int generic_xdp_lua_install_prog(char *lua_prog)
+{
+	struct lua_state_cpu *sc;
+
+	list_for_each_entry(sc, &lua_state_cpu_list, list) {
+		if (luaL_dostring(sc->L, lua_prog)) {
+			pr_err(KERN_INFO "error: %s\nOn cpu: %d\n",
+				lua_tostring(sc->L, -1), sc->cpu);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+#endif /* CONFIG_XDP_LUA */
+
 static int netif_receive_skb_internal(struct sk_buff *skb)
 {
 	int ret;
@@ -10462,6 +10491,9 @@ static struct pernet_operations __net_initdata default_device_ops = {
 static int __init net_dev_init(void)
 {
 	int i, rc = -ENOMEM;
+#ifdef CONFIG_XDP_LUA
+	struct lua_state_cpu *new_state_cpu;
+#endif /* CONFIG_XDP_LUA */
 
 	BUG_ON(!dev_boot_phase);
 
@@ -10476,6 +10508,9 @@ static int __init net_dev_init(void)
 		INIT_LIST_HEAD(&ptype_base[i]);
 
 	INIT_LIST_HEAD(&offload_base);
+#ifdef CONFIG_XDP_LUA
+	INIT_LIST_HEAD(&lua_state_cpu_list);
+#endif /* CONFIG_XDP_LUA */
 
 	if (register_pernet_subsys(&netdev_net_ops))
 		goto out;
@@ -10506,6 +10541,25 @@ static int __init net_dev_init(void)
 		init_gro_hash(&sd->backlog);
 		sd->backlog.poll = process_backlog;
 		sd->backlog.weight = weight_p;
+
+#ifdef CONFIG_XDP_LUA
+		new_state_cpu = (struct lua_state_cpu *)
+			kmalloc(sizeof(struct lua_state_cpu), GFP_ATOMIC);
+		if (!new_state_cpu)
+			continue;
+
+		new_state_cpu->L = luaL_newstate();
+		if  (!new_state_cpu->L) {
+			kfree(new_state_cpu);
+			continue;
+		}
+
+		luaL_openlibs(new_state_cpu->L);
+		lua_pop(new_state_cpu->L, 1);
+		new_state_cpu->cpu = i;
+
+		list_add(&new_state_cpu->list, &lua_state_cpu_list);
+#endif /* CONFIG_XDP_LUA */
 	}
 
 	dev_boot_phase = 0;