-
Notifications
You must be signed in to change notification settings - Fork 3.3k
/
proxy_ratelim.c
165 lines (138 loc) · 5.17 KB
/
proxy_ratelim.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
#include "proxy.h"
// No GC necessary.
struct mcp_ratelim_tbf {
uint32_t bucket;
uint32_t limit;
uint32_t fill_rate; // tokens to add per tick rate
uint32_t tick_rate; // in milliseconds
int64_t last_update; // time in milliseconds
};
struct mcp_ratelim_global_tbf {
struct mcp_globalobj_s g;
struct mcp_ratelim_tbf tbf;
};
#define TIMEVAL_TO_MILLIS(n) (n.tv_usec / 1000 + n.tv_sec * (uint64_t)1000)
// global config VM object GC
int mcplib_ratelim_global_tbf_gc(lua_State *L) {
struct mcp_ratelim_global_tbf *lim = luaL_checkudata(L, 1, "mcp.ratelim_global_tbf");
assert(lim->g.refcount == 0);
mcp_gobj_finalize(&lim->g);
// no other memory to directly free, just kill the mutex.
return 0;
}
// worker thread proxy object GC
int mcplib_ratelim_proxy_tbf_gc(lua_State *L) {
struct mcp_ratelim_global_tbf **lim_p = luaL_checkudata(L, 1, "mcp.ratelim_proxy_tbf");
struct mcp_ratelim_global_tbf *lim = *lim_p;
proxy_ctx_t *ctx = PROXY_GET_THR_CTX(L);
mcp_gobj_unref(ctx, &lim->g);
return 0;
}
int mcp_ratelim_proxy_tbf(lua_State *from, lua_State *to) {
// from, -3 should have the userdata.
struct mcp_ratelim_global_tbf *lim = luaL_checkudata(from, -3, "mcp.ratelim_global_tbf");
struct mcp_ratelim_global_tbf **lim_p = lua_newuserdatauv(to, sizeof(struct mcp_ratelim_global_tbf *), 0);
luaL_setmetatable(to, "mcp.ratelim_proxy_tbf");
*lim_p = lim;
lua_pushvalue(from, -3); // copy ratelim obj to ref below
mcp_gobj_ref(from, &lim->g); // pops obj copy
return 0;
}
static lua_Integer _tbf_check(lua_State *L, char *key) {
lua_Integer n = 0;
if (lua_getfield(L, 1, key) != LUA_TNIL) {
n = lua_tointeger(L, -1);
if (n < 0 || n > UINT_MAX-1) {
proxy_lua_error(L, "mcp.ratelim_tbf: arguments must be unsigned 32 bit integer");
}
}
lua_pop(L, 1); // pops value or nil.
return n;
}
static void _setup_tbf(lua_State *L, struct mcp_ratelim_tbf *lim) {
struct timeval now;
luaL_checktype(L, 1, LUA_TTABLE);
lim->limit = _tbf_check(L, "limit");
lim->fill_rate = _tbf_check(L, "fillrate");
lim->tick_rate = _tbf_check(L, "tickrate");
// seed the token bucket filter.
lim->bucket = lim->limit;
gettimeofday(&now, NULL);
lim->last_update = TIMEVAL_TO_MILLIS(now);
}
int mcplib_ratelim_tbf(lua_State *L) {
struct mcp_ratelim_tbf *lim = lua_newuserdatauv(L, sizeof(*lim), 0);
memset(lim, 0, sizeof(*lim));
luaL_setmetatable(L, "mcp.ratelim_tbf");
_setup_tbf(L, lim);
return 1;
}
int mcplib_ratelim_global_tbf(lua_State *L) {
struct mcp_ratelim_global_tbf *lim = lua_newuserdatauv(L, sizeof(*lim), 0);
memset(lim, 0, sizeof(*lim));
// TODO: during next refactor, add "globalobj init" phase, which probably
// just does this.
pthread_mutex_init(&lim->g.lock, NULL);
luaL_setmetatable(L, "mcp.ratelim_global_tbf");
_setup_tbf(L, &lim->tbf);
return 1;
}
static int _update_tbf(struct mcp_ratelim_tbf *lim, int take, uint64_t now) {
uint64_t delta = 0;
delta = now - lim->last_update;
if (delta > lim->tick_rate) {
// find how many ticks to add to the bucket.
uint32_t toadd = delta / lim->tick_rate;
// advance time up to the most recent tick.
lim->last_update += toadd * lim->tick_rate;
// add tokens to the bucket
lim->bucket += toadd * lim->fill_rate;
if (lim->bucket > lim->limit) {
lim->bucket = lim->limit;
}
}
if (lim->bucket > take) {
lim->bucket -= take;
return 1;
} else {
return 0;
}
}
int mcplib_ratelim_tbf_call(lua_State *L) {
struct mcp_ratelim_tbf *lim = luaL_checkudata(L, 1, "mcp.ratelim_tbf");
luaL_checktype(L, 2, LUA_TNUMBER);
int take = lua_tointeger(L, 2);
struct timeval now;
uint64_t now_millis = 0;
gettimeofday(&now, NULL);
now_millis = TIMEVAL_TO_MILLIS(now);
lua_pushboolean(L, _update_tbf(lim, take, now_millis));
return 1;
}
// NOTE: it should be possible to run a TBF using atomics, in the future when
// we start to support C11 atomics.
// Flip the concept of checking the time, updating, then subtracting the take
// to:
// - how much "time elapsed" is necessary for the take requested
// - atomically load the old time
// - if not enough time delta between old time and now, return false
// - else atomically swap the update time with the new time
// - compare and update the oldtime to newtime
// - not sure how much perf this buys you. would have to test.
int mcplib_ratelim_proxy_tbf_call(lua_State *L) {
struct mcp_ratelim_global_tbf **lim_p = luaL_checkudata(L, 1, "mcp.ratelim_proxy_tbf");
// line was kinda long / hard to read.
struct mcp_ratelim_global_tbf *lim = *lim_p;
struct timeval now;
luaL_checktype(L, 2, LUA_TNUMBER);
int take = lua_tointeger(L, 2);
gettimeofday(&now, NULL);
uint64_t now_millis = 0;
now_millis = TIMEVAL_TO_MILLIS(now);
pthread_mutex_lock(&lim->g.lock);
int res = _update_tbf(&lim->tbf, take, now_millis);
pthread_mutex_unlock(&lim->g.lock);
lua_pushboolean(L, res);
return 1;
}