add XDPLua #7

VictorNogueiraRio · 2020-08-11T16:32:49Z

No description provided.

VictorNogueiraRio · 2020-08-11T16:33:20Z

include/net/xdp.h

+	struct lua_State	*L;
+	struct work_struct	work;
+	spinlock_t		lock;
+	bool			init;


s/init/inuse/

I was about to add this comment ;-)

VictorNogueiraRio · 2020-08-11T16:33:51Z

net/core/filter.c

@@ -5849,6 +5855,278 @@ static const struct bpf_func_proto bpf_tcp_gen_syncookie_proto = {

 #endif /* CONFIG_INET */

+#ifdef CONFIG_XDP_LUA
+
+static inline void verify_and_lock(void) {


Suggested change, by @lneto

static inline lua_State *xdplua_lock(void) { struct xdplua_create_work *lw; lw = this_cpu_ptr(&luaworks); if (!lw->inuse) { lw->inuse = true; spin_lock(&lw->lock); } return lw->L; }

please, take care about {.. please review the whole patch..

VictorNogueiraRio · 2020-08-11T16:34:22Z

net/core/filter.c

+	}
+}
+
+BPF_CALL_2(bpf_lua_dataref, struct xdp_buff *, ctx, int, offset) {


Suggested change, by @lneto

BPF_CALL_2(bpf_lua_dataref, struct xdp_buff *, ctx, int, offset) { lua_State *L; if (ctx->data_end <= offset + ctx->data) return -1; L = xdplua_lock(); return ldata_newref(L, ctx->data + offset, ctx->data_end - ctx->data - offset); }

btw, I got your concern about moving such declarations to another file.. but we can solve this using some macro sorcery.. however, we can leave it as a TODO.. let's merge this PR first..

VictorNogueiraRio · 2020-08-11T16:44:57Z

include/net/xdp.h

@@ -63,13 +63,30 @@ struct xdp_rxq_info {
 	struct xdp_mem_info mem;
 } ____cacheline_aligned; /* perf critical, avoid false-sharing */

+#ifdef CONFIG_XDP_LUA
+struct xdplua_create_work {
+	char				lua_script[8192];


s/8192/MAXSCRIPTLEN/

XDPLUA_MAX_SCRIPT_LEN or XDPLUA_MAXSCRIPTLEN? any variation looks good for me.. 👍

VictorNogueiraRio · 2020-08-11T17:00:41Z

include/net/xdp.h

 struct xdp_buff {
 	void *data;
 	void *data_end;
 	void *data_meta;
 	void *data_hard_start;
 	unsigned long handle;
 	struct xdp_rxq_info *rxq;
+#ifdef CONFIG_XDP_LUA


With the creation of struct xdplua_create_work there probably is no reason to modify struct xdp_buff

VictorNogueiraRio · 2020-08-11T17:09:32Z

include/net/xdp.h

@@ -63,13 +63,30 @@ struct xdp_rxq_info {
 	struct xdp_mem_info mem;
 } ____cacheline_aligned; /* perf critical, avoid false-sharing */

+#ifdef CONFIG_XDP_LUA
+struct xdplua_create_work {


Maybe we should add a field of luadata's datarefs into this struct to automate the reference control of these objects

@VictorNogueiraRio it makes sense to me.. also, we should rename this struct.. perhaps, xdplua_work.. create_work sounds like a function..

VictorNogueiraRio · 2020-08-11T17:11:12Z

net/core/dev.c

+		lw->L = luaL_newstate();
+		WARN_ON(!lw->L);
+
+		if (!lw->L)


We need to improve this, @lneto any suggestions?

IMHO, we should fail XDPLua initiation completely and destroy all states we have created so far.. and, of course, disable XDPLua execution in runtime putting a guard..

btw, another example of what I was arguing on slack is to move all this code to a xdplua_init() function

VictorNogueiraRio · 2020-08-11T17:20:07Z

net/core/dev.c

+
+	for_each_possible_cpu(cpu) {
+		lw = per_cpu_ptr(&luaworks, cpu);
+		strcpy(lw->lua_script, lua_script);


strncpy(lw->lua_script, lua_script, MAXSCRIPTLEN);

VictorNogueiraRio · 2020-08-11T17:22:35Z

net/core/rtnetlink.c

@@ -1876,6 +1876,9 @@ static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = {
 	[IFLA_XDP_ATTACHED]	= { .type = NLA_U8 },
 	[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 },


s/8192/MAXSCRIPTLEN

VictorNogueiraRio · 2020-08-12T00:50:18Z

include/uapi/linux/bpf.h

+ *		1 if the value at the given index of the Lua stack is a
+ *		string; otherwise it returns 0
+ *
+ * void bpf_lua_type(void *ctx, int index)


s/void/int/

VictorNogueiraRio · 2020-08-12T00:50:57Z

tools/include/uapi/linux/bpf.h

+ *		1 if the value at the given index of the Lua stack is a
+ *		string; otherwise it returns 0
+ *
+ * void bpf_lua_type(void *ctx, int index)


s/void/int/

lneto · 2020-09-01T18:40:08Z

net/core/dev.c

+int generic_xdp_lua_install_prog(char *lua_script)
+{
+	int cpu;
+	struct xdplua_create_work *lw;


this variable can be moved to the for_each scope, right?

lneto · 2020-09-01T18:44:27Z

net/core/filter.c

+#ifdef CONFIG_XDP_LUA
+#include <lua.h>
+#include <luadata.h>
+#include <luaunpack.h>


one example of what I was arguing on slack is to have one single header to xdplua, e.g., xdplua.h

lneto · 2020-09-01T18:58:59Z

net/core/filter.c

+	if (lua_isstring(ctx->L, index)) {
+		strncpy(str, lua_tostring(ctx->L, index), size);
+		return 1;
+	}


let's handle the exception case first.. suggestion:

if (!lua_isstring(ctx->L, index)) return 0; strncpy(str, lua_tostring(ctx->L, index), size); return 1;

@VictorNogueiraRio what's the use case, if we have none, I would simply remove this helper. At least, I would rename it to something like bpf_lua_copystring. Also, I believe you should pop the string out of the stack, right?

lneto · 2020-09-01T19:18:53Z

net/core/filter.c

@@ -5925,6 +6203,38 @@ bpf_base_func_proto(enum bpf_func_id func_id)
 		return bpf_get_trace_printk_proto();
 	case BPF_FUNC_jiffies64:
 		return &bpf_jiffies64_proto;
+#ifdef CONFIG_XDP_LUA
+	case BPF_FUNC_lua_dataref:


we could automate it using a macro.. e.g., XDP_LUA_BPF_FUNC(lua_dataref);

lneto · 2020-09-01T19:20:08Z

net/core/rtnetlink.c

@@ -2806,6 +2809,21 @@ static int do_setlink(const struct sk_buff *skb,
 				goto errout;
 			status |= DO_SETLINK_NOTIFY;
 		}
+


lneto · 2020-09-01T19:20:11Z

net/core/rtnetlink.c

+				goto errout;
+		}
+#endif  /* CONFIG_XDP_LUA */
+


lneto · 2020-09-01T19:25:49Z

samples/bpf/map.lua

+
+function update(map)
+	xdp.map_update(map, 1, 3)
+end


we should move this file out of this PR

lneto · 2020-09-01T19:26:10Z

samples/bpf/xdplua_map_kern.c

+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";


we should move this file out of this PR

lneto · 2020-09-01T19:26:19Z

samples/bpf/checkcookie.lua

+	end
+
+	return cookies[ip] == cookiepkt and true or false
+end


we should move this file out of this PR

lneto · 2020-09-01T19:27:23Z

samples/bpf/xdplua_cookie_kern.c

+	return parse_tcp(ctx, data, ip_off, data_end, saddr);
+}
+
+char _license[] SEC("license") = "GPL";


we should move this file out of this PR

lneto · 2020-09-01T19:33:46Z

samples/bpf/xdplua_user.c

+
+	if (monitor) {
+		rx_cnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rx_cnt");
+


lneto · 2020-09-01T19:35:19Z

samples/bpf/xdplua_user.c

+		}
+	}
+
+


lneto · 2020-09-01T19:54:37Z

tools/include/uapi/linux/bpf.h

+ *
+ * int bpf_lua_dataref(void *ctx, int offset)
+ *	Description
+ *		Create a new lua data buffer object pointing to the captured


Suggested change

* Create a new lua data buffer object pointing to the captured

* Creates a new lua data object pointing to the captured

lneto · 2020-09-01T19:56:17Z

tools/include/uapi/linux/bpf.h

+ *		packet at the specified offset. The function leaves the new 
+ *		object on top of the Lua stack.
+ *	Return
+ *		Data object reference number on success, or -1 in case


Suggested change

* Data object reference number on success, or -1 in case

* Data object reference number on success, or LUA_NOREF in case

lneto · 2020-09-01T20:56:34Z

net/core/filter.c

+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_lua_pcall, struct xdp_buff *, ctx, char *, funcname,


@VictorNogueiraRio I believed we have already discussed that we should just wrap lua_pcall and allow the caller to handle the errors..

lneto · 2020-09-01T20:56:50Z

net/core/filter.c

+
+	base += num_rets;
+
+clean_state:


lneto · 2020-09-01T20:57:47Z

net/core/filter.c

+BPF_CALL_2(bpf_lua_pushmap, struct xdp_buff *, ctx, struct bpf_map *, map) {
+	verify_and_lock();
+	lua_pushlightuserdata(ctx->L, map);
+	return 0;


do we always need to return int even if we want a void?

lneto · 2020-09-01T21:02:50Z

net/core/filter.c

+	return 0;
+}
+
+static const struct bpf_func_proto bpf_lua_pushlstring_proto = {


I really believe we can have a macro to generate the wrapper.. including such struct..

P.S.: we can leave it as a TODO, of course..

lneto · 2020-09-01T21:04:36Z

net/core/filter.c

+};
+
+BPF_CALL_2(bpf_lua_type, struct xdp_buff *, ctx, int, index) {
+       return lua_type(ctx->L, index);


are you sure we don't need to lock here?

lneto · 2020-09-01T21:06:50Z

tools/include/uapi/linux/bpf.h

+ *		Converts the Lua value at the given index of the Lua
+ *		stack to a C string and copies size bytes of it to
+ *		value pointed by str
+ *	Return


you said it's void above..

lneto · 2020-09-01T21:07:52Z

tools/include/uapi/linux/bpf.h

+ *		following constants defined in lua.h: LUA_TNIL (0),
+ *		LUA_TNUMBER, LUA_TBOOLEAN, LUA_TSTRING, LUA_TTABLE,
+ *		LUA_TFUNCTION, LUA_TUSERDATA, LUA_TTHREAD, and
+ *		LUA_TLIGHTUSERDATA.


we don't need this long description.. you can just refer to the manual or lua.h itself as you're doing already..

lneto · 2020-09-01T21:08:19Z

tools/include/uapi/linux/bpf.h

+ *		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.


we don't need to replicate Lua's manual here.. just refer to it..

this comment refers to all wrappers.. please, review all..

lneto · 2020-09-01T21:08:33Z

tools/include/uapi/linux/bpf.h

+ *
+ * void bpf_lua_pushskb(void *ctx)
+ *	Description
+ *		Pushes an SKB structure onto the Lua stack


we are going to get rid of this, right?

lneto · 2020-09-01T21:12:16Z

net/core/rtnetlink.c

+
+#ifdef CONFIG_XDP_LUA
+		if (xdp[IFLA_XDP_LUA_PROG]) {
+			char *lua_prog = nla_data(xdp[IFLA_XDP_LUA_PROG]);


script? I think we should uniformize it.. we are using both lua_prog and lua_script in the code.. I would rename them all to script

lneto

I think moving the code from dev.c, filter.c and rtnetlink.c to a xdplua.c would cleanup the patch considerably.

marcelstanley

Just adding a minor request. I still need to do a thorough review.

marcelstanley · 2020-09-01T20:30:39Z

samples/bpf/xdplua_user.c

+
+	lua_prog = (char *) malloc(prog_size + 1);
+	memset(lua_prog, 0, prog_size + 1);
+	if (fread(lua_prog, 1, prog_size, f) < 0) {


From #3

Suggested change

if (fread(lua_prog, 1, prog_size, f) < 0) {

size_t read = fread(lua_prog, 1, prog_size, f);

if (read < 0) {

VictorNogueiraRio and others added 12 commits May 28, 2020 19:01

add Lunatik submodule

4d82fa2

add XDPLua

ff7c9b9

add LuaData submodule

f278687

add LuaXDP submodule

7d184d9

add LuaRCU submodule

7e405cf

add XDPLua map sample

13a42eb

Fix script loading synchronization issue

5eb463c

add LuaUnpack submodule

e20f358

Add bpf_lua_tostring function

36ceb19

Add bpf_lua_type function

040b06b

Add javascript challenge sample

50e056a

Improve xdplua_user's packet counting

b6ca132

VictorNogueiraRio requested review from mizvekov and lneto August 11, 2020 16:32

VictorNogueiraRio commented Aug 11, 2020

View reviewed changes

fixup! Add javascript challenge sample

2eebe24

VictorNogueiraRio force-pushed the vnogueira-5.6_nolimit branch from bdd9779 to 2eebe24 Compare August 11, 2020 16:39

VictorNogueiraRio commented Aug 11, 2020

View reviewed changes

VictorNogueiraRio commented Aug 12, 2020

View reviewed changes

VictorNogueiraRio added 3 commits August 14, 2020 01:11

fixup! add XDPLua

a768499

fixup! add Lunatik submodule

5e89868

fixup! add XDPLua

deac020