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13#include <linux/ktime.h>
14#include <linux/module.h>
15#include <linux/skbuff.h>
16#include <linux/types.h>
17#include <linux/netfilter/x_tables.h>
18#include <linux/netfilter/xt_time.h>
19
20struct xtm {
21 u_int8_t month;
22 u_int8_t monthday;
23 u_int8_t weekday;
24 u_int8_t hour;
25 u_int8_t minute;
26 u_int8_t second;
27 unsigned int dse;
28};
29
30extern struct timezone sys_tz;
31
32static const u_int16_t days_since_year[] = {
33 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334,
34};
35
36static const u_int16_t days_since_leapyear[] = {
37 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335,
38};
39
40
41
42
43
44enum {
45 DSE_FIRST = 2039,
46};
47static const u_int16_t days_since_epoch[] = {
48
49 25202, 24837, 24472, 24106, 23741, 23376, 23011, 22645, 22280, 21915,
50
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 % 86400;
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 return;
153}
154
155static bool
156time_mt(const struct sk_buff *skb, const struct xt_match_param *par)
157{
158 const struct xt_time_info *info = par->matchinfo;
159 unsigned int packet_time;
160 struct xtm current_time;
161 s64 stamp;
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171
172 if (skb->tstamp.tv64 == 0)
173 __net_timestamp((struct sk_buff *)skb);
174
175 stamp = ktime_to_ns(skb->tstamp);
176 stamp = div_s64(stamp, NSEC_PER_SEC);
177
178 if (info->flags & XT_TIME_LOCAL_TZ)
179
180 stamp -= 60 * sys_tz.tz_minuteswest;
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191 if (stamp < info->date_start || stamp > info->date_stop)
192 return false;
193
194 packet_time = localtime_1(¤t_time, stamp);
195
196 if (info->daytime_start < info->daytime_stop) {
197 if (packet_time < info->daytime_start ||
198 packet_time > info->daytime_stop)
199 return false;
200 } else {
201 if (packet_time < info->daytime_start &&
202 packet_time > info->daytime_stop)
203 return false;
204 }
205
206 localtime_2(¤t_time, stamp);
207
208 if (!(info->weekdays_match & (1 << current_time.weekday)))
209 return false;
210
211
212 if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
213 localtime_3(¤t_time, stamp);
214 if (!(info->monthdays_match & (1 << current_time.monthday)))
215 return false;
216 }
217
218 return true;
219}
220
221static bool time_mt_check(const struct xt_mtchk_param *par)
222{
223 const struct xt_time_info *info = par->matchinfo;
224
225 if (info->daytime_start > XT_TIME_MAX_DAYTIME ||
226 info->daytime_stop > XT_TIME_MAX_DAYTIME) {
227 printk(KERN_WARNING "xt_time: invalid argument - start or "
228 "stop time greater than 23:59:59\n");
229 return false;
230 }
231
232 return true;
233}
234
235static struct xt_match xt_time_mt_reg __read_mostly = {
236 .name = "time",
237 .family = NFPROTO_UNSPEC,
238 .match = time_mt,
239 .checkentry = time_mt_check,
240 .matchsize = sizeof(struct xt_time_info),
241 .me = THIS_MODULE,
242};
243
244static int __init time_mt_init(void)
245{
246 int minutes = sys_tz.tz_minuteswest;
247
248 if (minutes < 0)
249 printk(KERN_INFO KBUILD_MODNAME
250 ": kernel timezone is +%02d%02d\n",
251 -minutes / 60, -minutes % 60);
252 else
253 printk(KERN_INFO KBUILD_MODNAME
254 ": kernel timezone is -%02d%02d\n",
255 minutes / 60, minutes % 60);
256
257 return xt_register_match(&xt_time_mt_reg);
258}
259
260static void __exit time_mt_exit(void)
261{
262 xt_unregister_match(&xt_time_mt_reg);
263}
264
265module_init(time_mt_init);
266module_exit(time_mt_exit);
267MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
268MODULE_DESCRIPTION("Xtables: time-based matching");
269MODULE_LICENSE("GPL");
270MODULE_ALIAS("ipt_time");
271MODULE_ALIAS("ip6t_time");
272