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12#include <linux/ktime.h>
13#include <linux/module.h>
14#include <linux/skbuff.h>
15#include <linux/types.h>
16#include <linux/netfilter/x_tables.h>
17#include <linux/netfilter/xt_time.h>
18
19struct xtm {
20 u_int8_t month;
21 u_int8_t monthday;
22 u_int8_t weekday;
23 u_int8_t hour;
24 u_int8_t minute;
25 u_int8_t second;
26 unsigned int dse;
27};
28
29extern struct timezone sys_tz;
30
31static const u_int16_t days_since_year[] = {
32 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334,
33};
34
35static const u_int16_t days_since_leapyear[] = {
36 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335,
37};
38
39
40
41
42
43enum {
44 DSE_FIRST = 2039,
45 SECONDS_PER_DAY = 86400,
46};
47static const u_int16_t days_since_epoch[] = {
48
49 25202, 24837, 24472, 24106, 23741, 23376, 23011, 22645, 22280, 21915,
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51 21550, 21184, 20819, 20454, 20089, 19723, 19358, 18993, 18628, 18262,
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53 17897, 17532, 17167, 16801, 16436, 16071, 15706, 15340, 14975, 14610,
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55 14245, 13879, 13514, 13149, 12784, 12418, 12053, 11688, 11323, 10957,
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57 10592, 10227, 9862, 9496, 9131, 8766, 8401, 8035, 7670, 7305,
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59 6940, 6574, 6209, 5844, 5479, 5113, 4748, 4383, 4018, 3652,
60
61 3287, 2922, 2557, 2191, 1826, 1461, 1096, 730, 365, 0,
62};
63
64static inline bool is_leap(unsigned int y)
65{
66 return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
67}
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76
77static inline unsigned int localtime_1(struct xtm *r, time_t time)
78{
79 unsigned int v, w;
80
81
82 v = time % SECONDS_PER_DAY;
83 r->second = v % 60;
84 w = v / 60;
85 r->minute = w % 60;
86 r->hour = w / 60;
87 return v;
88}
89
90static inline void localtime_2(struct xtm *r, time_t time)
91{
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96 r->dse = time / 86400;
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102 r->weekday = (4 + r->dse - 1) % 7 + 1;
103}
104
105static void localtime_3(struct xtm *r, time_t time)
106{
107 unsigned int year, i, w = r->dse;
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117 for (i = 0, year = DSE_FIRST; days_since_epoch[i] > w;
118 ++i, --year)
119 ;
120
121 w -= days_since_epoch[i];
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138 if (is_leap(year)) {
139
140 for (i = ARRAY_SIZE(days_since_leapyear) - 1;
141 i > 0 && days_since_leapyear[i] > w; --i)
142 ;
143 r->monthday = w - days_since_leapyear[i] + 1;
144 } else {
145 for (i = ARRAY_SIZE(days_since_year) - 1;
146 i > 0 && days_since_year[i] > w; --i)
147 ;
148 r->monthday = w - days_since_year[i] + 1;
149 }
150
151 r->month = i + 1;
152}
153
154static bool
155time_mt(const struct sk_buff *skb, struct xt_action_param *par)
156{
157 const struct xt_time_info *info = par->matchinfo;
158 unsigned int packet_time;
159 struct xtm current_time;
160 s64 stamp;
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171 if (skb->tstamp.tv64 == 0)
172 __net_timestamp((struct sk_buff *)skb);
173
174 stamp = ktime_to_ns(skb->tstamp);
175 stamp = div_s64(stamp, NSEC_PER_SEC);
176
177 if (info->flags & XT_TIME_LOCAL_TZ)
178
179 stamp -= 60 * sys_tz.tz_minuteswest;
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190 if (stamp < info->date_start || stamp > info->date_stop)
191 return false;
192
193 packet_time = localtime_1(¤t_time, stamp);
194
195 if (info->daytime_start < info->daytime_stop) {
196 if (packet_time < info->daytime_start ||
197 packet_time > info->daytime_stop)
198 return false;
199 } else {
200 if (packet_time < info->daytime_start &&
201 packet_time > info->daytime_stop)
202 return false;
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211
212 if ((info->flags & XT_TIME_CONTIGUOUS) &&
213 packet_time <= info->daytime_stop)
214 stamp -= SECONDS_PER_DAY;
215 }
216
217 localtime_2(¤t_time, stamp);
218
219 if (!(info->weekdays_match & (1 << current_time.weekday)))
220 return false;
221
222
223 if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
224 localtime_3(¤t_time, stamp);
225 if (!(info->monthdays_match & (1 << current_time.monthday)))
226 return false;
227 }
228
229 return true;
230}
231
232static int time_mt_check(const struct xt_mtchk_param *par)
233{
234 const struct xt_time_info *info = par->matchinfo;
235
236 if (info->daytime_start > XT_TIME_MAX_DAYTIME ||
237 info->daytime_stop > XT_TIME_MAX_DAYTIME) {
238 pr_info("invalid argument - start or "
239 "stop time greater than 23:59:59\n");
240 return -EDOM;
241 }
242
243 if (info->flags & ~XT_TIME_ALL_FLAGS) {
244 pr_info("unknown flags 0x%x\n", info->flags & ~XT_TIME_ALL_FLAGS);
245 return -EINVAL;
246 }
247
248 if ((info->flags & XT_TIME_CONTIGUOUS) &&
249 info->daytime_start < info->daytime_stop)
250 return -EINVAL;
251
252 return 0;
253}
254
255static struct xt_match xt_time_mt_reg __read_mostly = {
256 .name = "time",
257 .family = NFPROTO_UNSPEC,
258 .match = time_mt,
259 .checkentry = time_mt_check,
260 .matchsize = sizeof(struct xt_time_info),
261 .me = THIS_MODULE,
262};
263
264static int __init time_mt_init(void)
265{
266 int minutes = sys_tz.tz_minuteswest;
267
268 if (minutes < 0)
269 printk(KERN_INFO KBUILD_MODNAME
270 ": kernel timezone is +%02d%02d\n",
271 -minutes / 60, -minutes % 60);
272 else
273 printk(KERN_INFO KBUILD_MODNAME
274 ": kernel timezone is -%02d%02d\n",
275 minutes / 60, minutes % 60);
276
277 return xt_register_match(&xt_time_mt_reg);
278}
279
280static void __exit time_mt_exit(void)
281{
282 xt_unregister_match(&xt_time_mt_reg);
283}
284
285module_init(time_mt_init);
286module_exit(time_mt_exit);
287MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
288MODULE_DESCRIPTION("Xtables: time-based matching");
289MODULE_LICENSE("GPL");
290MODULE_ALIAS("ipt_time");
291MODULE_ALIAS("ip6t_time");
292